Sample records for radio frequency identification

  1. SECURING RADIO FREQUENCY IDENTIFICATION (RFID)

    E-Print Network [OSTI]

    business process for an organization; as a result, the security risks for RFID systems and the controls for an organization; as a result, the security risks for RFID systems and the controls available to address themMay 2007 SECURING RADIO FREQUENCY IDENTIFICATION (RFID) SYSTEMS SECURING RADIO FREQUENCY

  2. Security approaches for Radio Frequency Identification systems

    E-Print Network [OSTI]

    Foley, Joseph Timothy, 1976-

    2007-01-01T23:59:59.000Z

    In this thesis, I explore the challenges related to the security of the Electronic Product Code (EPC) class of Radio Frequency Identification (RFID) tags and associated data. RFID systems can be used to improve supply chain ...

  3. Radio-frequency identification could help reduce the spread of plant pathogens

    E-Print Network [OSTI]

    Luvisi, Andrea; Panattoni, Alessandra; Triolo, Enrico

    2012-01-01T23:59:59.000Z

    ReVIEW Article Radio-frequency identification could helpcertified nursery stock. Radio- frequency identification (Panattoni and Enrico Triolo Radio-frequency identification (

  4. Radio frequency identification (RFID) applications in semiconductor manufacturing

    E-Print Network [OSTI]

    Cassett, David Ian, 1971-

    2004-01-01T23:59:59.000Z

    Radio frequency identification (RFID) has an enormous potential impact within the semiconductor supply chain, especially within semiconductor manufacturing. The end benefit of RFID will be in the mass serialization, and ...

  5. Radio frequency detection assembly and method for detecting radio frequencies

    DOE Patents [OSTI]

    Cown, Steven H. (Rigby, ID); Derr, Kurt Warren (Idaho Falls, ID)

    2010-03-16T23:59:59.000Z

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  6. In-Born Radio Frequency Identification Devices for Safeguards Use at Gas-Centrifuge Enrichment Plants

    SciTech Connect (OSTI)

    Ward,R.; Rosenthal,M.

    2009-07-12T23:59:59.000Z

    Global expansion of nuclear power has made the need for improved safeguards measures at Gas Centrifuge Enrichment Plants (GCEPs) imperative. One technology under consideration for safeguards applications is Radio Frequency Identification Devices (RFIDs). RFIDs have the potential to increase IAEA inspector"s efficiency and effectiveness either by reducing the number of inspection visits necessary or by reducing inspection effort at those visits. This study assesses the use of RFIDs as an integral component of the "Option 4" safeguards approach developed by Bruce Moran, U.S. Nuclear Regulatory Commission (NRC), for a model GCEP [1]. A previous analysis of RFIDs was conducted by Jae Jo, Brookhaven National Laboratory (BNL), which evaluated the effectiveness of an RFID tag applied by the facility operator [2]. This paper presents a similar evaluation carried out in the framework of Jo’s paper, but it is predicated on the assumption that the RFID tag is applied by the manufacturer at the birth of the cylinder, rather than by the operator. Relevant diversion scenarios are examined to determine if RFIDs increase the effectiveness and/ or efficiency of safeguards in these scenarios. Conclusions on the benefits offered to inspectors by using in-born RFID tagging are presented.

  7. RADIO FREQUENCY IDENTIFICATION DEVICES: EFFECTIVENESS IN IMPROVING SAFEGUARDS AT GAS-CENTRIFUGE URANIUM-ENRICHMENT PLANTS.

    SciTech Connect (OSTI)

    JOE,J.

    2007-07-08T23:59:59.000Z

    Recent advances in radio frequency identification devices (RFIDs) have engendered a growing interest among international safeguards experts. Potentially, RFIDs could reduce inspection work, viz. the number of inspections, number of samples, and duration of the visits, and thus improve the efficiency and effectiveness of international safeguards. This study systematically examined the applications of RFIDs for IAEA safeguards at large gas-centrifuge enrichment plants (GCEPs). These analyses are expected to help identify the requirements and desirable properties for RFIDs, to provide insights into which vulnerabilities matter most, and help formulate the required assurance tests. This work, specifically assesses the application of RFIDs for the ''Option 4'' safeguards approach, proposed by Bruce Moran, U. S. Nuclear Regulatory Commission (NRC), for large gas-centrifuge uranium-enrichment plants. The features of ''Option 4'' safeguards include placing RFIDs on all feed, product and tails (F/P/T) cylinders, along with WID readers in all FP/T stations and accountability scales. Other features of Moran's ''Option 4'' are Mailbox declarations, monitoring of load-cell-based weighing systems at the F/P/T stations and accountability scales, and continuous enrichment monitors. Relevant diversion paths were explored to evaluate how RFIDs improve the efficiency and effectiveness of safeguards. Additionally, the analysis addresses the use of RFIDs in conjunction with video monitoring and neutron detectors in a perimeter-monitoring approach to show that RFIDs can help to detect unidentified cylinders.

  8. Stabilized radio frequency quadrupole

    DOE Patents [OSTI]

    Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

    1984-01-01T23:59:59.000Z

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  9. Demonstration (DEMO) of Radio Frequency Identification (RFID) system for tracking and monitoring of nuclear materials.

    SciTech Connect (OSTI)

    Tsai, H. C.; Chen, K.; Liu, Y. Y.; Shuler, J. (Decision and Information Sciences); (USDOE)

    2010-01-01T23:59:59.000Z

    The US Department of Energy (DOE) [Environmental Management (EM), Office of Packaging and Transportation (EM-45)] Packaging Certification Program (PCP) has developed a radiofrequency identification (RFID) tracking and monitoring system for the management of nuclear materials packages during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, involves hardware modification, application software development, secured database and web server development, and irradiation experiments. In April 2008, Argonne tested key features of the RFID tracking and monitoring system in a weeklong, 1700 mile (2736 km) demonstration employing 14 empty type B fissile material drums of three designs (models 9975, 9977 and ES-3100) that have been certified for shipment by the DOE and the US Nuclear Regulatory Commission. The demonstration successfully integrated global positioning system (GPS) technology for vehicle tracking, satellite/cellular (general packet radio service, or GPRS) technologies for wireless communication, and active RFID tags with multiple sensors (seal integrity, shock, temperature, humidity and battery status) on drums. In addition, the demonstration integrated geographic information system (GIS) technology with automatic alarm notifications of incidents and generated buffer zone reports for emergency response and management of staged incidents. The demonstration was sponsored by EM and the US National Nuclear Security Administration, with the participation of Argonne, Savannah River and Oak Ridge National Laboratories. Over 50 authorised stakeholders across the country observed the demonstration via secured Internet access. The DOE PCP and national laboratories are working on several RFID system implementation projects at selected DOE sites, as well as continuing device and systems development and widening applications beyond DOE sites and possibly beyond nuclear materials to include other radioactive materials.

  10. "To appear in Bureau, S., Prabhu, B. S., & Gadh, R. 2008. Radio Frequency Identification: Beyond the Myths. A case for Health Care. Paper presented at the Academy of Management, 8-13 aot, Anaheim, Ca, USA"

    E-Print Network [OSTI]

    California at Los Angeles, University of

    15923 1 "To appear in Bureau, S., Prabhu, B. S., & Gadh, R. 2008. Radio Frequency Identification, School of Engineering University of California, Los Angeles & R. Gadh Professor, School of Engineering

  11. Rajit Gadh and B.S. Prabhu, Radio Frequency Identification (RFID) for the assistance of Katrina related disaster mortuary operations, IEEE Signal Processing, expected to appear March 2006, based on invitation to write short article.

    E-Print Network [OSTI]

    California at Los Angeles, University of

    Rajit Gadh and B.S. Prabhu, Radio Frequency Identification (RFID) for the assistance of Katrina of Katrina Hurricane Victims Rajit Gadh and B.S. Prabhu Recently news.com reported that the U.S. Disaster

  12. Stabilized radio-frequency quadrupole

    DOE Patents [OSTI]

    Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

    1982-09-29T23:59:59.000Z

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  13. Report on a 2009 mini-demonstration of the ARG-US Radio Frequency Identification (RFID) system in transportation.

    SciTech Connect (OSTI)

    Tsai, H.; Chen, K.; Jusko, M.; Craig, B.; Liu, Y.; Decision and Information Sciences

    2009-11-23T23:59:59.000Z

    The Packaging Certification Program (PCP) of the U.S. Department of Energy (DOE) Environmental Management (EM), Office of Packaging and Transportation (EM-14), has developed a radio frequency identification (RFID) tracking and monitoring system for the management of nuclear materials during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, consists of hardware (Mk-series sensor tags, fixed and handheld readers, form factor for multiple drum types, seal integrity sensors, and enhanced battery management), software (application programming interface, ARG-US software for local and remote/web applications, secure server and database management), and cellular/satellite communication interfaces for vehicle tracking and item monitoring during transport. The ability of the above system to provide accurate, real-time tracking and monitoring of the status of multiple, certified containers of nuclear materials has been successfully demonstrated in a week-long, 1,700-mile DEMO performed in April 2008. While the feedback from the approximately fifty (50) stakeholders who participated in and/or observed the DEMO progression were very positive and encouraging, two major areas of further improvements - system integration and web application enhancement - were identified in the post-DEMO evaluation. The principal purpose of the MiniDemo described in this report was to verify these two specific improvements. The MiniDemo was conducted on August 28, 2009. In terms of system integration, a hybrid communication interface - combining the RFID item-monitoring features and a commercial vehicle tracking system by Qualcomm - was developed and implemented. In the MiniDemo, the new integrated system worked well in reporting tag status and vehicle location accurately and promptly. There was no incompatibility of components. The robust commercial communication gear, as expected, helped improve system reliability. The MiniDemo confirmed that system integration is technically feasible and reliable with the existing RFID and Qualcomm satellite equipment. In terms of web application, improvements in mapping, tracking, data presentation, and post-incident spatial query reporting were implemented in ARG-US, the application software that manages the dataflow among the RFID tags, readers, and servers. These features were tested in the MiniDemo and found to be satisfactory. The resulting web application is both informative and user-friendly. A joint developmental project is being planned between the PCP and the DOE TRANSCOM that uses the Qualcomm gear in vehicles for tracking and communication of radioactive material shipments across the country. Adding an RFID interface to TRANSCOM is a significant enhancement to the DOE infrastructure for tracking and monitoring shipments of radioactive materials.

  14. Microwave and Radio Frequency Workshop

    Broader source: Energy.gov [DOE]

    At the Microwave and Radio Frequency Workshop (held in Long Beach, CA, on July 25, 2012), academic and industry experts discussed the existing and emerging electrotechnologies – such as microwave ...

  15. Medium-Sized Mammals around a Radioactive Liquid Waste Lagoon at Los Alamos National Laboratory: Uptake of Contaminants and Evaluation of Radio-Frequency Identification Technology

    SciTech Connect (OSTI)

    Leslie A. Hansen; Phil R. Fresquez; Rhonda J. Robinson; John D. Huchton; Teralene S. Foxx

    1999-11-01T23:59:59.000Z

    Use of a radioactive liquid waste lagoon by medium-sized mammals and levels of tritium, other selected radionuclides, and metals in biological tissues of the animals were documented at Technical Area 53 (TA-53) of Los Alamos National Laboratory during 1997 and 1998. Rock squirrel (Spermophilus variegates), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and bobcat (Lynx rufus) were captured at TA-53 and at a control site on the Santa Fe National Forest. Captured animals were anesthetized and marked with radio-frequency identification (RFD) tags and/or ear tags. We collected urine and hair samples for tritium and metals (aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and thallium) analyses, respectively. In addition, muscle and bone samples from two rock squirrels collected from each of TA-53, perimeter, and regional background sites were tested for tritium, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, and total uranium. Animals at TA-53 were monitored entering and leaving the lagoon area using a RFID monitor to read identification numbers from the RFID tags of marked animals and a separate camera system to photograph all animals passing through the monitor. Cottontail rabbit (Sylvilagus spp.), rock squirrel, and raccoon were the species most frequently photographed going through the RFID monitor. Less than half of all marked animals in the lagoon area were detected using the lagoon. Male and female rock squirrels from the lagoon area had significantly higher tritium concentrations compared to rock squirrels from the control area. Metals tested were not significantly higher in rock squirrels from TA-53, although there was a trend toward increased levels of lead in some individuals at TA-53. Muscle and bone samples from squirrels in the lagoon area appeared to have higher levels of tritium, total uranium, and {sup 137}Cs than samples collected from perimeter and background locations. However, the committed effective dose equivalent estimated from the potential human consumption of the muscle and bone tissue from these rock squirrels did not suggest any human health risk. Indirect routes of tritium uptake, possibly through consumption of vegetation, are important for animals in the lagoon area.

  16. RADIO FREQUENCY PHASE IN THE FEL SECTION OF A TBA

    E-Print Network [OSTI]

    Kuenning, R.W.

    2008-01-01T23:59:59.000Z

    Amplitude Control of the Radio Frequency Wave in the Two-Madison, WI, August 21-27, 1986 RADIO FREQUENCY PHASE IN THEAC03-76SF00098 LBL- 223Pl RADIO FREQUENCY PHASE IN THE FEL

  17. Multi-mode radio frequency device

    DOE Patents [OSTI]

    Gilbert, Ronald W. (Morgan Hill, CA); Carrender, Curtis Lee (Morgan Hill, CA); Anderson, Gordon A. (Benton City, WA); Steele, Kerry D. (Kennewick, WA)

    2007-02-13T23:59:59.000Z

    A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

  18. High power radio frequency attenuation device

    DOE Patents [OSTI]

    Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)

    1984-01-01T23:59:59.000Z

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  19. Microwave (MW) and Radio Frequency (RF) as Enabling Technologies...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for Advanced Manufacturing Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for Advanced...

  20. Advanced Radio Frequency-Based Sensors for Monitoring Diesel...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Radio Frequency-Based Sensors for Monitoring Diesel Particulate Filter Loading and Regeneration Advanced Radio Frequency-Based Sensors for Monitoring Diesel Particulate Filter...

  1. Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel...

    Office of Environmental Management (EM)

    Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel Consumption, Wins R&D 100 Award Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel Consumption, Wins R&D...

  2. Radio frequency (RF) heated supersonic flow laboratory

    SciTech Connect (OSTI)

    Wantuck, P.; Watanabe, H.

    1990-01-01T23:59:59.000Z

    A unique supersonic flow apparatus which employs an inductively-coupled, radio frequency (RF) torch to supply high enthalpy source gas to the nozzle inlet is described. The main features of this system are the plasma tube, a cooled nozzle assembly, and a combustion/expansion chamber with a heat exchanger. A description of these components with current test data is presented. In addition, a discussion of anticipated experiments utilizing this system is included.

  3. Radio Science, Volume ???, Number , Pages 15, Radio Frequency Interference Mitigation for Detection

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Radio Science, Volume ???, Number , Pages 1­5, Radio Frequency Interference Mitigation for Detection of Extended Sources with an Interferometer Geoffrey C. Bower Radio Astronomy Laboratory, UC Berkeley, Berkeley, CA 94720, USA Radio frequency interference (RFI) is a significant problem for current

  4. Radio-frequency scanning tunnelling microscopy U. Kemiktarak1

    E-Print Network [OSTI]

    LETTERS Radio-frequency scanning tunnelling microscopy U. Kemiktarak1 , T. Ndukum3 , K. C. Schwab3 measurementsinmesoscopicelectronicsandmechanics. Broadband noise measurements across the tunnel junction using this radio-frequency STM available from nanoscale optical and electrical displacement detection tech- niques, and the radio

  5. High efficiency, oxidation resistant radio frequency susceptor

    DOE Patents [OSTI]

    Besmann, Theodore M.; Klett, James W.

    2004-10-26T23:59:59.000Z

    An article and method of producing an article for converting energy from one form to another having a pitch-derived graphitic foam carbon foam substrate and a single layer coating applied to all exposed surfaces wherein the coating is either silicon carbide or carbides formed from a Group IVA metal. The article is used as fully coated carbon foam susceptors that more effectively absorb radio frequency (RF) band energy and more effectively convert the RF energy into thermal band energy or sensible heat. The essentially non-permeable coatings also serve as corrosion or oxidation resistant barriers.

  6. Radio-Frequency Rectification on Membrane Bound Pores

    E-Print Network [OSTI]

    Sujatha Ramachandran; Robert H. Blick; Daniel W. van der Weide

    2007-09-12T23:59:59.000Z

    We present measurements on direct radio-frequency pumping of ion channels and pores bound in bilipid membranes. We make use of newly developed microcoaxes, which allow delivering the high frequency signal in close proximity to the membrane bound proteins and ion channels. We find rectification of the radio-frequency signal, which is used to pump ions through the channels and pores.

  7. E4.18 Radio Frequency Electronics Copyright 2006 Dr Stepan Lucyszyn Frequency Spectrum

    E-Print Network [OSTI]

    Papavassiliou, Christos

    Applications Phased-array radar Electronic warfare (e.g. Electronic Surveillance Measures, ECM, ECCM, decoysE4.18 Radio Frequency Electronics Copyright © 2006 Dr Stepan Lucyszyn Frequency Spectrum and Applications #12;E4.18 Radio Frequency Electronics Copyright © 2006 Dr Stepan Lucyszyn #12;E4.18 Radio

  8. Radio frequency analog electronics based on carbon nanotube transistors

    E-Print Network [OSTI]

    Rogers, John A.

    Radio frequency analog electronics based on carbon nanotube transistors Coskun Kocabas*, Hoon properties of individ- ual tubes. We have implemented solutions to some of these challenges to yield radio band with power gains as high as 14 dB. As a demon- stration, we fabricated nanotube transistor radios

  9. An improved integrally formed radio frequency quadrupole

    DOE Patents [OSTI]

    Abbott, S.R.

    1987-10-05T23:59:59.000Z

    An improved radio frequency quadrupole is provided having an elongate housing with an elongate central axis and top, bottom and two side walls symmetrically disposed about the axis, and vanes formed integrally with the walls, the vanes each having a cross-section at right angles to the central axis which tapers inwardly toward the axis to form electrode tips spaced from each other by predetermined distances. Each of the four walls, and the vanes integral therewith, is a separate structural element having a central lengthwise plane passing through the tip of the vane, the walls having flat mounting surfaces at right angles to and parallel to the control plane, respectively, which are butted together to position the walls and vane tips relative to each other. 4 figs.

  10. Circuits and passive components for radio-frequency power conversion

    E-Print Network [OSTI]

    Han, Yehui, Ph. D. Massachusetts Institute of Technology

    2010-01-01T23:59:59.000Z

    This thesis focuses on developing technology for high efficiency power converters operating at very high frequencies. The work in the thesis involves two aspects of such converters: rf (radio-frequency) power circuit design ...

  11. CITY OF PRINCE GEORGE: RADIO FREQUENCY TREATMENT OF PARTIALLY

    E-Print Network [OSTI]

    #12;CITY OF PRINCE GEORGE: RADIO FREQUENCY TREATMENT OF PARTIALLY DIGESTED/DEWATERED BIOSOLIDS/DEWATERED BIOSOLIDS FINAL REPORT SUMMARY The City of Prince George recently proposed to investigate the possibility of applying radio frequency (RF) technology to partially digested/dewatered biosolids from domestic wastewater

  12. Trirotron: triode rotating beam radio frequency amplifier

    DOE Patents [OSTI]

    Lebacqz, Jean V. (Stanford, CA)

    1980-01-01T23:59:59.000Z

    High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.

  13. Method and apparatus for radio frequency ceramic sintering

    DOE Patents [OSTI]

    Hoffman, D.J.; Kimrey, H.D. Jr.

    1993-11-30T23:59:59.000Z

    Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents. 6 figures.

  14. Method and apparatus for radio frequency ceramic sintering

    DOE Patents [OSTI]

    Hoffman, Daniel J. (Oak Ridge, TN); Kimrey, Jr., Harold D. (Knoxville, TN)

    1993-01-01T23:59:59.000Z

    Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents.

  15. Radio-Frequency Beam Conditioner for Fast-Wave Free-Electron Generators of Coherent Radiation

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2008-01-01T23:59:59.000Z

    to Physical Review Letters Radio-Frequency Beam ConditionerDE-AC03-76SF00098 LBL-31006 RADIO-FREQUENCY BEAM CONDITIONERIbaraki, 305, Japan. RADIO-FREQUENCY BEAM CONDITIONER FOR

  16. High-power radio-frequency attenuation device

    DOE Patents [OSTI]

    Kerns, Q.A.; Miller, H.W.

    1981-12-30T23:59:59.000Z

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  17. argon radio-frequency glow: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Institute of Standards and Technology RFID is a form of automatic 6 Radio frequency ion source CERN Preprints Summary: The study on Radio Frequency Ion Source is mainly...

  18. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    SciTech Connect (OSTI)

    Dowla, F

    2007-03-14T23:59:59.000Z

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  19. Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator

    SciTech Connect (OSTI)

    Peng, Shixiang, E-mail: sxpeng@pku.edu.cn; Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China)] [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); Zhang, Ailing; Chen, Jia'er [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China) [SKLNPT and IHIP, School of Physics, Peking University, Beijing 100871 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2014-02-15T23:59:59.000Z

    A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 ??mm?mrad and the fraction of He+ is about 99%.

  20. Radio-frequency spectroscopy of ultracold atomic Fermi gases

    E-Print Network [OSTI]

    Schirotzek, Andre

    2010-01-01T23:59:59.000Z

    This thesis presents experiments investigating the phase diagram of ultracold atomic Fermi gases using radio-frequency spectroscopy. The tunability of many experimental parameters including the temperature, the interparticle ...

  1. Numerical modelling of a radio-frequency micro ion thruster

    E-Print Network [OSTI]

    Tsay, Michael Meng-Tsuan

    2006-01-01T23:59:59.000Z

    A simple performance model is developed for an inductively-coupled radio-frequency micro ion thruster. Methods of particle and energy balance are utilized for modeling the chamber plasma discharge. A transformer model is ...

  2. Predicting low-frequency radio fluxes of known extrasolar planets

    E-Print Network [OSTI]

    Grießmeier, J -M; Spreeuw, H

    2008-01-01T23:59:59.000Z

    Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does ...

  3. Radio frequency overview of the high explosive radio telemetry project

    SciTech Connect (OSTI)

    Bracht, R. [Los Alamos National Lab., NM (United States); Dimsdle, J.; Rich, D.; Smith, F. [AlliedSignal Federal Manufacturing and Technologies, Kansas City, MO (United States)

    1998-12-31T23:59:59.000Z

    High explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal Federal Manufacturing and Technologies. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data with the limited time interval available.

  4. Suppression of radio frequency knock out in stacked beams by phase shifting the betatron oscillations

    E-Print Network [OSTI]

    Terwilliger, K M

    1957-01-01T23:59:59.000Z

    Suppression of radio frequency knock out in stacked beams by phase shifting the betatron oscillations

  5. Predicting low-frequency radio fluxes of known extrasolar planets

    E-Print Network [OSTI]

    J. -M. Grießmeier; P. Zarka; H. Spreeuw

    2008-06-02T23:59:59.000Z

    Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does not predict any observable emission for the present exoplanet census. We also give estimates for the planetary magnetic dipole moment of all currently known extrasolar planets, which will be useful for other studies. Conclusions. Our results show that observations of exoplanetary radio emission are feasible, but that the number of promising targets is not very high. The catalog of targets will be particularly useful for current and future radio observation campaigns (e.g. with the VLA, GMRT, UTR-2 and with LOFAR).

  6. Radio frequency dc-dc power conversion

    E-Print Network [OSTI]

    Rivas, Juan, 1976-

    2007-01-01T23:59:59.000Z

    THIS THESIS addresses the development of system architectures and circuit topologies for dc-dc power conversion at very high frequencies. The systems architectures that are developed are structured to overcome limitations ...

  7. Frequency Dependence of Radio Images of Supernova Remnants

    E-Print Network [OSTI]

    A. V. Karnaushenko; E. Yu. Bannikova; V. M. Kontorovich

    2007-12-10T23:59:59.000Z

    Radio images of supernova remnants in the framework of diffusion model are discussed. The distribution profiles of synchrotron radiation intensity for spherical injection source of relativistic electrons are reduced at different frequencies. An explanation of the observational data obtained on UTR-2, according to which the size of the supernova remnant at decametric waves is larger than the remnant size at high frequencies, is given.

  8. Power Supplies and Radio Frequency Department at Culham

    E-Print Network [OSTI]

    Power Supplies and Radio Frequency Department at Culham Culham Centre for Fusion Energy #12;We employ over 70 power electrical and power electronic engineers and technicians. The department supplies power to the JET and MAST nuclear fusion experiments at Culham. Culham is fed from the grid at 400k

  9. Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

    E-Print Network [OSTI]

    Choueiri, Edgar

    rights reserved. #12;Abstract A new electrodeless accelerator concept, called Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD), that relies on an RF-assisted discharge to produce a plasma, an applied magnetic field to guide the plasma into the acceleration region, and an induced current sheet

  10. Localized radio frequency communication using asynchronous transfer mode protocol

    DOE Patents [OSTI]

    Witzke, Edward L. (Edgewood, NM); Robertson, Perry J. (Albuquerque, NM); Pierson, Lyndon G. (Albuquerque, NM)

    2007-08-14T23:59:59.000Z

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  11. Surface Studies on Niobium for Superconductivity Radio Frequency (SRF) Accelerator

    E-Print Network [OSTI]

    Shaw, Leah B.

    Surface Studies on Niobium for Superconductivity Radio Frequency (SRF) Accelerator Hui Tian College Kelley, Professor of Applied Science Abstract Niobium rf superconductivity is a nanoscale, near employed treatment-BCP on polycrystalline niobium sheet over a range of realistic solution flow rates has

  12. K-BAND RADIO FREQUENCY INTERFERENCE SURVEY OF SOUTHEASTERN MICHIGAN

    E-Print Network [OSTI]

    Ruf, Christopher

    K-BAND RADIO FREQUENCY INTERFERENCE SURVEY OF SOUTHEASTERN MICHIGAN Shannon Curry1 , Michael Ahlers University of Michigan 2455 Hayward St. Ann Arbor, MI 48109-2143 USA cruf@umich.edu 2 DTU Space Technical resolution. A K-Band airborne version has been built and flown across southeast Michigan. A kurtosis detector

  13. Exploring the magnetized cosmic web through low frequency radio emission

    E-Print Network [OSTI]

    N. Battaglia; C. Pfrommer; J. L. Sievers; J. R. Bond; T. A. Ensslin

    2009-08-07T23:59:59.000Z

    Recent improvements in the capabilities of low frequency radio telescopes provide a unique opportunity to study thermal and non-thermal properties of the cosmic web. We argue that the diffuse, polarized emission from giant radio relics traces structure formation shock waves and illuminates the large-scale magnetic field. To show this, we model the population of shock-accelerated relativistic electrons in high-resolution cosmological simulations of galaxy clusters and calculate the resulting radio synchrotron emission. We find that individual shock waves correspond to localized peaks in the radio surface brightness map which enables us to measure Mach numbers for these shocks. We show that the luminosities and number counts of the relics strongly depend on the magnetic field properties, the cluster mass and dynamical state. By suitably combining different cluster data, including Faraday rotation measures, we are able to constrain some macroscopic parameters of the plasma at the structure formation shocks, such as models of turbulence. We also predict upper limits for the properties of the warm-hot intergalactic medium, such as its temperature and density. We predict that the current generation of radio telescopes (LOFAR, GMRT, MWA, LWA) have the potential to discover a substantially larger sample of radio relics, with multiple relics expected for each violently merging cluster. Future experiments (SKA) should enable us to further probe the macroscopic parameters of plasma physics in clusters.

  14. A Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

    E-Print Network [OSTI]

    Economou, Demetre J.

    either in a conven- tional microwave oven or by using a radio frequency (RF) induction coil-consistently the power absorbed by the preform from a radio frequency induction coil. The model equations were solved

  15. Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins

    E-Print Network [OSTI]

    Griffin, Robert G.

    Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins Marc Baldus quadrupolar spins in the presence of an appropriate radio-frequency field. Experimental and theoretical in close spatial proximity. Unfortunately, most spin-1/2 methods involving radio frequency rf irradiation

  16. Radio frequency induced ionized collisional flow model for application at atmospheric pressures

    E-Print Network [OSTI]

    Roy, Subrata

    Radio frequency induced ionized collisional flow model for application at atmospheric pressures and radio frequency (rf) induced plasma-sheath dynamics, using multifluid equations. For the former, argon inherent in nonequilibrium discharges such as obtained through radio frequency (rf) or microwave excitation

  17. Radio frequency communication system utilizing radiating transmission lines

    DOE Patents [OSTI]

    Struven, Warren C. (San Carlos, CA)

    1984-01-01T23:59:59.000Z

    A radio communication system for use in tunnels, mines, buildings or other shielded locations in which a pair of radiating transmission lines (30), (31) extend through such location in spaced coextensive relation to each other. Each transmission line (30), (31) has at least one unidirectional amplifier (32), (33) interposed therein with the sense of the unidirectional amplifier (32) of one transmission line (30) being opposite to the sense of the unidirectional amplifier (33) of the other transmission line (31). Each of the amplifiers (32), (33) has a gain which is less than the coupling loss between the transmission lines (30), (31). Two or more mobile transceivers (35) in the location served by the system are coupled to the transmission lines (30), (31) by electromagnetic wave propagation in space in order to communicate directly with each other at a given radio frequency within the frequency range of the system.

  18. Final report: In situ radio frequency heating demonstration

    SciTech Connect (OSTI)

    Jarosch, T.R.; Beleski, R.J.; Faust, D.

    1994-01-05T23:59:59.000Z

    A field demonstration of in situ radio frequency heating was performed at the Savannah River Site (SRS) as part of the US Department of Energy-Office of Technology Development`s Integrated Demonstration. The objective of the demonstration was to investigate the effectiveness of in situ radio frequency (RF) heating as an enhancement to vacuum extraction of residual solvents (primarily trichloroethylene and perchloroethylene) held in vadose zone clay deposits. Conventional soil vacuum extraction techniques are mass transfer limited because of the low permeabilities of the clays. By selectively heating the clays to temperatures at or above 100{degrees}C, the release or transport of the solvent vapors will be enhanced as a result of several factors including an increase in the contaminant vapor pressure and diffusivity and an increase in the effective permeability of the formation with the release of water vapor.

  19. Frequency-based structural damage identification and dynamic system characterisation 

    E-Print Network [OSTI]

    Mao, Lei

    2012-11-29T23:59:59.000Z

    This thesis studies structural dynamic system identification in a frequency-based framework. The basic consideration stems from the fact that frequencies may generally be measured with higher accuracy than other pertinent ...

  20. Background radio-frequency radiation and its impact on radio astronomy Michelle C. Storey, Bruce MacA Thomas and John M. Sarkissian

    E-Print Network [OSTI]

    Sarkissian, John M.

    1 Background radio-frequency radiation and its impact on radio astronomy Michelle C. Storey, Bruce 1710 Email:mstorey@atnf.csiro.au Abstract: The use of radio-frequency telecommunications equipment is dramatically increasing, and one consequence is that background levels of radio-frequency radiation

  1. Ross Ice Shelf in situ radio-frequency ice attenuation

    E-Print Network [OSTI]

    Taylor Barrella; Steven Barwick; David Saltzberg

    2012-05-01T23:59:59.000Z

    We have measured the in situ average electric field attenuation length for radio-frequency signals broadcast vertically through the Ross Ice Shelf. We chose a location, Moore Embayment, south of Minna Bluff, known for its high reflectivity at the ice-sea interface. We confirmed specular reflection and used the return pulses to measure the average attenuation length from 75-1250 MHz over the round-trip distance of 1155 m. We find the average electric field attenuation length to vary from 500 m at 75 MHz to 300 m at 1250 MHz, with an experimental uncertainty of 55 to 15 m. We discuss the implications for neutrino telescopes that use the radio technique and include the Ross Ice Shelf as part of their sensitive volume.

  2. Flux pinning characteristics in cylindrical niobium samples used for superconducting radio frequency cavity fabrication

    E-Print Network [OSTI]

    Flux pinning characteristics in cylindrical niobium samples used for superconducting radio.1088/0953-2048/25/6/065014 Flux pinning characteristics in cylindrical niobium samples used for superconducting radio frequency-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency

  3. CENSORS: A Combined EIS-NVSS Survey Of Radio Sources. I. Sample definition, radio data and optical identifications

    E-Print Network [OSTI]

    P. N. Best; J. N. Arts; H. J. A. Rottgering; R. Rengelink; M. H. Brookes; J. Wall

    2003-08-22T23:59:59.000Z

    A new sample of radio sources, with the designated name CENSORS (A Combined EIS-NVSS Survey Of Radio Sources), has been defined by combining the NRAO VLA Sky Survey (NVSS) at 1.4 GHz with the ESO Imaging Survey (EIS) Patch D, a 3 by 2 degree region of sky centred at 09 51 36.0, -21 00 00 (J2000). New radio observations of 199 NVSS radio sources with NVSS flux densities S(1.4GHz) > 7.8mJy are presented, and compared with the EIS I-band imaging observations which reach a depth of I~23; optical identifications are obtained for over two-thirds of the ~150 confirmed radio sources within the EIS field. The radio sources have a median linear size of 6 arcseconds, consistent with the trend for lower flux density radio sources to be less extended. Other radio source properties, such as the lobe flux density ratios, are consistent with those of brighter radio source samples. From the optical information, 30-40% of the sources are expected to lie at redshifts z >~ 1.5. One of the key goals of this survey is to accurately determine the high redshift evolution of the radio luminosity function. These radio sources are at the ideal flux density level to achieve this goal; at redshifts z~2 they have luminosities which are around the break of the luminosity function and so provide a much more accurate census of the radio source population at those redshifts than the existing studies of extreme, high radio power sources. Other survey goals include investigating the dual--population unification schemes for radio sources, studying the radio luminosity dependence of the evolution of radio source environments, and understanding the radio power dependence of the K-z relation for radio galaxies.

  4. Hermetic aluminum radio frequency interconnection and method for making

    DOE Patents [OSTI]

    Kilgo, Riley D. (Albuquerque, NM); Kovacic, Larry (Albuquerque, NM); Brow, Richard K. (Rolla, MO)

    2000-01-01T23:59:59.000Z

    The present invention provides a light-weight, hermetic coaxial radio-frequency (RF) interconnection having an electrically conductive outer housing made of aluminum or an aluminum alloy, a central electrical conductor made of ferrous or non-ferrous material, and a cylinder of dielectric material comprising a low-melting-temperature, high-thermal-expansion aluminophosphate glass composition for hermetically sealing between the aluminum-alloy outer housing and the ferrous or non-ferrous center conductor. The entire RF interconnection assembly is made permanently hermetic by thermally fusing the center conductor, glass, and housing concurrently by bringing the glass to the melt point by way of exposure to an atmospheric temperature sufficient to melt the glass, less than 540.degree. C., but that does not melt the center conductor or the outer aluminum or aluminum alloy housing. The composition of the glass used is controlled to provide a suitable low dielectric constant so that an appropriate electrical characteristic impedance, for example 50 ohms, can be achieved for an electrical interconnection that performs well at high radio frequencies and also provides an interconnection maintaining a relatively small physical size.

  5. Design, development, and acceleration trials of radio-frequency quadrupole

    SciTech Connect (OSTI)

    Rao, S. V. L. S., E-mail: svlsrao@gmail.com; Jain, Piyush; Pande, Rajni; Roy, Shweta; Mathew, Jose V.; Kumar, Rajesh; Pande, Manjiri; Krishnagopal, S.; Gupta, S. K.; Singh, P. [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)] [Ion Accelerator Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-04-15T23:59:59.000Z

    A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 ?m leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (?±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D{sup +}) beam, we tested it by accelerating both the proton (H{sup +}) and D{sup +} beams. The RFQ was operated in pulsed mode and accelerated both H{sup +} and D{sup +} beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.

  6. Radio frequency sheaths in an oblique magnetic field

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Myra, James R.; D'Ippolito, Daniel A.

    2015-06-01T23:59:59.000Z

    The physics of radio-frequency (rf) sheaths near a conducting surface is studied for plasmas immersed in a magnetic field that makes an oblique angle ? with the surface. A set of one-dimensional equations is developed that describe the dynamics of the time-dependent magnetic presheath and non-neutral Debye sheath. The model employs Maxwell-Boltzmann electrons, and the magnetization and mobility of the ions is determined by the magnetic field strength, and wave frequency, respectively. The angle, ? assumed to be large enough to insure an electron-poor sheath, is otherwise arbitrary. Concentrating on the ion-cyclotron range of frequencies, the equations are solved numericallymore »to obtain the rectified (dc) voltage, the rf voltage across the sheath and the rf current flowing through the sheath. As an application of this model, the sheath voltage-current relation is used to obtain the rf sheath impedance, which in turn gives an rf sheath boundary condition for the electric field at the sheath-plasma interface that can be used in rf wave codes. In general the impedance has both resistive and capacitive contributions, and generalizes previous sheath boundary condition models. The resistive part contributes to parasitic power dissipation at the wall.« less

  7. Ultrafast electron diffraction with radio-frequency compressed electron pulses

    SciTech Connect (OSTI)

    Chatelain, Robert P.; Morrison, Vance R.; Godbout, Chris; Siwick, Bradley J. [Departments of Physics and Chemistry, Center for the Physics of Materials, McGill University, Montreal (Canada)

    2012-08-20T23:59:59.000Z

    We report on the complete characterization of time resolution in an ultrafast electron diffraction (UED) instrument based on radio-frequency electron pulse compression. The temporal impulse response function of the instrument was determined directly in pump-probe geometry by performing electron-laser pulse cross-correlation measurements using the ponderomotive interaction. With optimal settings, a stable impulse response of 334{+-}10 fs was measured at a bunch charge of 0.1 pC (6.24 Multiplication-Sign 10{sup 5} electrons/pulse); a dramatic improvement compared to performance without pulse compression. Phase stability currently limits the impulse response of the UED diffractometer to the range of 334-500 fs, for bunch charges ranging between 0.1 and 0.6 pC.

  8. Superconducting radio-frequency modules test faciilty operating experience

    SciTech Connect (OSTI)

    Soyars, W.; Bossert, R.; Darve, C.; Degraff, B.; Klebaner, A.; Martinez, A.; Pei, L.; Theilacker, J.; /Fermilab

    2007-07-01T23:59:59.000Z

    Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R&D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service Fermilab SRF R&D needs. The first stage of the project has been successfully completed, which allows for distribution of cryogens for a single cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at MDB results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project.

  9. Large area radio frequency plasma for microelectronics processing Z. Yu and D. Shaw

    E-Print Network [OSTI]

    Collins, George J.

    focus on wide area plasma uniformity and undesired antenna window erosion caused by the plasma. OurLarge area radio frequency plasma for microelectronics processing Z. Yu and D. Shaw Colorado State November 1994 Radio-frequency rf inductively coupled planar plasma ICP provides a better way to generate

  10. Resonant-frequency discharge in a multi-cell radio frequency cavity

    SciTech Connect (OSTI)

    Popovic, S; Upadhyay, J.; Mammosser, J.; Nikolic, M; Vuskovic, L

    2014-11-07T23:59:59.000Z

    We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problems related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.

  11. Phase Noise of the Radio Frequency (RF) Beatnote Generated by a Dual-Frequency VECSEL

    E-Print Network [OSTI]

    Syamsundar De; Abdelkrim El Amili; Ihsan Fsaifes; Grégoire Pillet; Ghaya Baili; Fabienne Goldfarb; Mehdi Alouini; Isabelle Sagnes; Fabien Bretenaker

    2013-11-13T23:59:59.000Z

    We analyze, both theoretically and experimentally, the phase noise of the radio frequency (RF) beatnote generated by optical mixing of two orthogonally polarized modes in an optically pumped dual-frequency Vertical External Cavity Surface Emitting Laser (VECSEL). The characteristics of the RF phase noise within the frequency range of 10 kHz - 50 MHz are investigated for three different nonlinear coupling strengths between the two lasing modes. In the theoretical model, we consider two different physical mechanisms responsible for the RF phase noise. In the low frequency domain (typically below 500 kHz), the dominant contribution to the RF phase noise is shown to come from the thermal fluctuations of the semicondutor active medium induced by pump intensity fluctuations. However, in the higher frequency domain (typically above 500 kHz), the main source of RF phase noise is shown to be the pump intensity fluctuations which are transfered to the intensity noises of the two lasing modes and then to the phase noise via the large Henry factor of the semiconductor gain medium. For this latter mechanism, the nonlinear coupling strength between the two lasing modes is shown to play an important role in the value of the RF phase noise. All experimental results are shown to be in good agreement with theory.

  12. Report on the development of a radio-frequency photo electron source with superconducting niobium cavity (SRF gun realization)

    E-Print Network [OSTI]

    Teichert, J; Büttig, H; Hempel, R; Janssen, D; Lehnert, U; Michel, P; Möller, K; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Lipka, D; Stephan, J; Lehmann, W D; Klemz, G; Will, I

    2007-01-01T23:59:59.000Z

    Report on the development of a radio-frequency photo electron source with superconducting niobium cavity (SRF gun realization)

  13. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    SciTech Connect (OSTI)

    Shawn M. Allan; Patricia M. Strickland; Holly S. Shulman

    2009-11-11T23:59:59.000Z

    Ceralink Inc. developed FastFuse™, a rapid, new, energy saving process for lamination of glass and composites using radio frequency (RF) heating technology. The Inventions and Innovations program supported the technical and commercial research and development needed to elevate the innovation from bench scale to a self-supporting technology with significant potential for growth. The attached report provides an overview of the technical and commerical progress achieved for FastFuse™ during the course of the project. FastFuse™ has the potential to revolutionize the laminate manufacturing industries by replacing energy intensive, multi-step processes with an energy efficient, single-step process that allows higher throughput. FastFuse™ transmits RF energy directly into the interlayer to generate heat, eliminating the need to directly heat glass layers and the surrounding enclosures, such as autoclaves or vacuum systems. FastFuse™ offers lower start-up and energy costs (up to 90% or more reduction in energy costs), and faster cycles times (less than 5 minutes). FastFuse™ is compatible with EVA, TPU, and PVB interlayers, and has been demonstrated for glass, plastics, and multi-material structures such as photovoltaics and transparent armor.

  14. Rapid prototyping for radio-frequency geolocation applications

    SciTech Connect (OSTI)

    Briles, S. C. (Scott C.); Arrowood, J. L. (Joseph L.); Braun, T. R. (Thomas R.); Turcotte, D. (Dakx); Fiset, E. (Etienne)

    2004-01-01T23:59:59.000Z

    Previous space-to-ground, single-platform geolocation experiments exploiting time-difference-of arrival (TDOA) via interferometry were successful at separating and quantitatively characterizing interfering radio frequency (RF) signals from expected RF transmissions. Much of the success of these experiments rested on the use of embedded processors to perform the required signal processing. The experiments handled data in a 'snapshot' fashion: digitized data was collected, the data was processed via a digital signal processing (DSP) microprocessor to yield differential phase measurements, and these measurements were transmitted to the Earth for geolocation processing. With the utilization of FPGAs (field programmable gate arrays) for the intensive number-crunching algorithms, the processing of streaming real-time data is feasible for bandwidths on the order of 20 MHz. By partitioning the signal processing algorithm so there is a significant reduction in the data rate as data flows through the FPGA, a DSP microprocessor can now be employed to perform further decision-oriented processing on the FPGA output. This hybrid architecture, employing both FPGAs and DSPs, typically requires an expensive and lengthy development cycle. However, the use of graphical development environments with auto-code generation and hardware-in-the-loop testing can result in rapid prototyping for geolocation experiments, which enables adaptation to emerging signals of interest in a cost and time effective manner.

  15. Radio-frequency dressed state potentials for neutral atoms

    E-Print Network [OSTI]

    S. Hofferberth; I. Lesanovsky; B. Fischer; J. Verdu; J. Schmiedmayer

    2006-08-29T23:59:59.000Z

    Potentials for atoms can be created by external fields acting on properties like magnetic moment, charge, polarizability, or by oscillating fields which couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here we present an experimental investigation of the remarkable properties of potentials derived from radio-frequency (RF) coupling between electronic ground states. The coupling is magnetic and the vector character allows to design state dependent potential landscapes. On atom chips this enables robust coherent atom manipulation on much smaller spatial scales than possible with static fields alone. We find no additional heating or collisional loss up to densities approaching $10^{15}$ atoms / cm$^3$ compared to static magnetic traps. We demonstrate the creation of Bose-Einstein condensates in RF potentials and investigate the difference in the interference between two independently created and two coherently split condensates in identical traps. All together this makes RF dressing a powerful new tool for micro manipulation of atomic and molecular systems.

  16. Method of making radio frequency ion source antenna

    DOE Patents [OSTI]

    Ehlers, Kenneth W. (Alamo, CA); Leung, Ka-Ngo (Hercules, CA)

    1988-01-01T23:59:59.000Z

    In the method, the radio frequency (RF) antenna is made by providing a clean coil made of copper tubing or other metal conductor, which is coated with a tacky organic binder, and then with a powdered glass frit, as by sprinkling the frit uniformly over the binder. The coil is then heated internally in an inert gas atmosphere, preferably by passing an electrical heating current along the coil. Initially, the coil is internally heated to about 200.degree. C. to boil off the water from the binder, and then to about 750.degree. C.-850.degree. C. to melt the glass frit, while also burning off the organic binder. The melted frit forms a molten glass coating on the metal coil, which is then cooled to solidify the glass, so that the metal coil is covered with a thin continuous homogeneous impervious glass coating of substantially uniform thickness. The glass coating affords complete electrical insulation and complete dielectric protection for the metal coil of the RF antenna, to withstand voltage breakdown and to prevent sputtering, while also doubling the plasma generating efficiency of the RF antenna, when energized with RF power in the vacuum chamber of an ion source for a particle accelerator or the like. The glass frit preferably contains apprxoimately 45% lead oxide.

  17. Fast radio-frequency amplitude modulation in multiple-quantum magic-angle-spinning nuclear magnetic resonance: Theory and experiments

    E-Print Network [OSTI]

    Frydman, Lucio

    Fast radio-frequency amplitude modulation in multiple-quantum magic-angle-spinning nuclear magnetic of this experiment has been the poor efficiency of the radio-frequency pulses used in converting multiple-modulated radio-frequency pulses, and which can yield substantial signal and even resolution enhancements over

  18. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    E-Print Network [OSTI]

    J. Avva; J. M. Kovac; C. Miki; D. Saltzberg; A. G. Vieregg

    2014-09-30T23:59:59.000Z

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. The measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as the most promising northern site for UHE neutrino detection.

  19. Energy Saving Glass Lamination via Selective Radio-Frequency Heating

    SciTech Connect (OSTI)

    Shulman, Holly S.; Allan, Shawn M.

    2009-11-11T23:59:59.000Z

    This Inventions and Innovations program supported the technical and commercial research and development needed to elevate Ceralink's energy saving process for flat glass lamination from bench scale to a self-supporting technology with significant potential for growth. Radio-frequency heating was any un-explored option for laminating glass prior to this program. With significant commercial success through time and energy savings in the wood, paper, and plastics industries, RF heating was found to have significant promise for the energy intensive glass lamination industry. A major technical goal of the program was to demonstrate RF lamination across a wide range of laminate sizes and materials. This was successfully accomplished, dispelling many skeptics' concerns about the abilities of the technology. Ceralink laminated panels up to 2 ft x 3 ft, with four sets processed simultaneously, in a 3 minute cycle. All major categories of interlayer materials were found to work with RF lamination. In addition to laminating glass, other materials including photovoltaic silicon solar cells, light emitting diodes, metallized glass, plastics (acrylic and polycarbonate), and ceramics (alumina) were found compatible with the RF process. This opens up a wide range of commercial opportunities beyond the initially targeted automotive industry. The dramatic energy savings reported for RF lamination at the bench scale were found to be maintained through the scale up of the process. Even at 2 ft x 3 ft panel sizes, energy savings are estimated to be at least 90% compared to autoclaving or vacuum lamination. With targeted promotion through conference presentations, press releases and internet presence, RF lamination has gained significant attention, drawing large audiences at American Ceramic Society meetings. The commercialization success of the project includes the establishment of a revenue-generating business model for providing process development and demonstrations for potential RF lamination users. A path to industrial energy benefits and revenue through industrial equipment sales was established in a partnership with Thermex Thermatron, a manufacturer of RF equipment.

  20. Scattering of radio frequency waves by blobs in tokamak plasmas

    SciTech Connect (OSTI)

    Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hizanidis, Kyriakos; Kominis, Yannis [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)] [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)

    2013-05-15T23:59:59.000Z

    The density fluctuations and blobs present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction, reflection, diffraction, and coupling to other plasma waves. This, in turn, affects the spectrum of the RF waves and the electromagnetic power that reaches the core of the plasma. The usual geometric optics analysis of RF scattering by density blobs accounts for only refractive effects. It is valid when the amplitude of the fluctuations is small, of the order of 10%, compared to the background density. In experiments, density fluctuations with much larger amplitudes are routinely observed, so that a more general treatment of the scattering process is needed. In this paper, a full-wave model for the scattering of RF waves by a blob is developed. The full-wave approach extends the range of validity well beyond that of geometric optics; however, it is theoretically and computationally much more challenging. The theoretical procedure, although similar to that followed for the Mie solution of Maxwell's equations, is generalized to plasmas in a magnetic field. Besides diffraction and reflection, the model includes coupling to a different plasma wave than the one imposed by the external antenna structure. In the model, it is assumed that the RF waves interact with a spherical blob. The plasma inside and around the blob is cold, homogeneous, and imbedded in a uniform magnetic field. After formulating the complete analytical theory, the effect of the blob on short wavelength electron cyclotron waves and longer wavelength lower hybrid waves is studied numerically.

  1. A Dedicated Search for Low Frequency Radio Transient Astrophysical Events using ETA

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Frequency Radio Transients, Eight-meter-wavelength Transient Array, Crab Giant Pulses, Gamma Ray Bursts-annihilation of primordial black holes (PBHs), gamma ray bursts (GRBs), and supernovae are expected to produce single

  2. Impedance matching and DC-DC converter designs for tunable radio frequency based mobile telecommunication systems 

    E-Print Network [OSTI]

    Wong, Yan Chiew

    2014-06-30T23:59:59.000Z

    Tunability and adaptability for radio frequency (RF) front-ends are highly desirable because they not only enhance functionality and performance but also reduce the circuit size and cost. This thesis presents a number ...

  3. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    E-Print Network [OSTI]

    Liekhus-Schmaltz, C E

    2011-01-01T23:59:59.000Z

    A senior undergraduate experiment has been developed for learning about frequency stabilization techniques using radio-frequency electronics. The primary objective is to frequency stabilize a voltage controlled oscillator to a cavity resonance at 800 MHz using the Pound-Drever-Hall scheme. This technique is commonly applied to stabilize lasers at optical frequencies, but by using radio-frequency equipment exclusively it is possible to systematically study various aspects of the technique more thoroughly, inexpensively, and free from eye hazards. Students also learn about modular radio-frequency electronics and basic feedback control loops. By varying the temperature of the resonator, the students may determine the thermal expansion coefficients of copper, aluminum, and super invar.

  4. Unprecedentedly Strong and Narrow Electromagnetic Emissions Stimulated by High-Frequency Radio Waves in the Ionosphere

    SciTech Connect (OSTI)

    Norin, L.; Leyser, T. B.; Nordblad, E.; Thide, B.; McCarrick, M. [Swedish Institute of Space Physics, Uppsala (Sweden); BAE Systems Advanced Technologies, Washington, D.C. (United States)

    2009-02-13T23:59:59.000Z

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

  5. Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

    SciTech Connect (OSTI)

    Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC

    2011-03-01T23:59:59.000Z

    The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC. Simulations studies and measurements were conducted that clearly show the correlation between RF noise and longitudinal bunch emittance, identify the major LLRF noise contributions, and determine the RF component dominating this effect. With these results, LHC upgrades and alternative algorithms are evaluated to reduce longitudinal emittance growth during operations. The applications of this work are described with regard to future machines and analysis of new technical implementations, as well as to possible future work which would continue the directions of this dissertation.

  6. Multi-Tag Radio Frequency Identification Systems Leonid Bolotnyy

    E-Print Network [OSTI]

    Robins, Gabriel

    numerous useful applications (e.g., supply chain management, inventory tracking, ac- cess control-active. Active tags can initi- ate transmission on their own. Passive and semi-active tags rely on power from: inductive coupling and electromagnetic backscattering, or far-field propagation. In inductive cou- pling

  7. Radio Frequency Identification (RFID) Stakeholder Meeting Dallas, Texas

    E-Print Network [OSTI]

    in U.S. disposal facilities. · Discussion of limiting pilot to trucks, or whether other modes with wastes brought from Mexico and abandoned in warehouses in Texas. Warehousing of hazardous waste in the U

  8. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    E-Print Network [OSTI]

    Le Roy, Robert J.

    Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators. The three main pieces of equipment are a commercial voltage controlled oscillator, a resonating cavity of the voltage controlled oscillator. The cavity resonance is then observed by scanning the frequency

  9. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    SciTech Connect (OSTI)

    Allan, Shawn M.; Baranova, Inessa; Poley, Joseph; Reis, Henrique

    2012-02-27T23:59:59.000Z

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 ���°C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination id

  10. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    SciTech Connect (OSTI)

    Allan, Shawn M.

    2012-02-27T23:59:59.000Z

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination identifying castable molds for

  11. Small Satellite Applications of Commercial off the Shelf Radio Frequency Integrated Circuits

    E-Print Network [OSTI]

    Graves, John

    2012-02-14T23:59:59.000Z

    from scratch. This opposite extreme requires an extensive set of tools and Radio Frequency (RF) expertise beyond that of most undergraduate 7 engineers. If a program is not careful the resulting cost of test equipment and resources to perform... available from manufacturers today. These chips are compact integrated circuits (IC) that feature combined data interface, RF oscillator, mixing, and amplification circuits. RFIC radio hardware is typically used in cell phone and wireless device...

  12. Single shot time stamping of ultrabright radio frequency compressed electron pulses

    SciTech Connect (OSTI)

    Gao, M.; Dwayne Miller, R. J. [Department of Chemistry and Physics, University of Toronto, Toronto, ON. M5S 3H6 (Canada); Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany); Jiang, Y.; Kassier, G. H. [Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany)

    2013-07-15T23:59:59.000Z

    We demonstrate a method of time-stamping Radio Frequency compressed electron bunches for Ultrafast Electron Diffraction experiments in the sub-pC regime. We use an in-situ ultra-stable photo-triggered streak camera to directly track the time of arrival of each electron pulse and correct for the timing jitter in the radio frequency synchronization. We show that we can correct for timing jitter down to 30 fs root-mean-square with minimal distortion to the diffraction patterns, and performed a proof-of-principle experiment by measuring the ultrafast electron-phonon coupling dynamics of silicon.

  13. Radio-Frequency Inverters With Transmission-Line Input Networks

    E-Print Network [OSTI]

    Phinney, Joshua W.

    A soft-switching inverter topology (the Class Phi ) is presented which draws dc source current through a transmission line or a lumped-network approximation of a distributed line. By aligning the inverter switching frequency ...

  14. Graphene for radio frequency electronics and infrared thermal imaging

    E-Print Network [OSTI]

    Hsu, Allen Long

    2015-01-01T23:59:59.000Z

    The aim of this thesis is two-fold: The first is to develop a reliable processing technology for CVD graphene devices for applications in graphene circuits, i.e. mixers, frequency multipliers and phase key shifters. The ...

  15. Resistance Compression Networks for Radio-Frequency Power Conversion

    E-Print Network [OSTI]

    Han, Yehui

    A limitation of many high-frequency resonant inverter topologies is their high sensitivity to loading conditions. This paper introduces a new class of matching networks that greatly reduces the load sensitivity of resonant ...

  16. Radio-nuclide mixture identification using medium energy resolution detectors

    DOE Patents [OSTI]

    Nelson, Karl Einar

    2013-09-17T23:59:59.000Z

    According to one embodiment, a method for identifying radio-nuclides includes receiving spectral data, extracting a feature set from the spectral data comparable to a plurality of templates in a template library, and using a branch and bound method to determine a probable template match based on the feature set and templates in the template library. In another embodiment, a device for identifying unknown radio-nuclides includes a processor, a multi-channel analyzer, and a memory operatively coupled to the processor, the memory having computer readable code stored thereon. The computer readable code is configured, when executed by the processor, to receive spectral data, to extract a feature set from the spectral data comparable to a plurality of templates in a template library, and to use a branch and bound method to determine a probable template match based on the feature set and templates in the template library.

  17. Self-excited nonlinear plasma series resonance oscillations in geometrically symmetric capacitively coupled radio frequency discharges

    SciTech Connect (OSTI)

    Donko, Z. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D. [Institute for Plasma and Atomic Physics, Ruhr-University Bochum, Bochum 44780 (Germany)

    2009-03-30T23:59:59.000Z

    At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies.

  18. LowFrequency Solar Radio Bursts from Green Bank

    E-Print Network [OSTI]

    White, Stephen

    waves at the plasma frequency that are converted into fundamental and har- monic electromagnetic waves of emission during the decline of the soft X­rays. The Type III bursts are attributed to beams of keV­energy (UT) 20040716 GBSRBS GOES FIGURE 4: Short­wave fadeout followed by a Type II burst. In this figure

  19. High latitude geomagnetically induced current events observed on very low frequency radio wave receiver systems

    E-Print Network [OSTI]

    Otago, University of

    High latitude geomagnetically induced current events observed on very low frequency radio wave induced current (GIC) in the Scottish power system in southern Scotland, during a storm event, and exhibit significantly different amplitude characteristics. Finally, we compared in detail the geomagnetic

  20. Controller design issues in the feedback control of radio frequency plasma processing reactors

    E-Print Network [OSTI]

    Kushner, Mark

    Controller design issues in the feedback control of radio frequency plasma processing reactors feedback control of inductively coupled plasma processing reactors for polysilicon etching and be successfully used for feedback control of plasma processing reactors.4 There are many control strate- gies

  1. Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting

    E-Print Network [OSTI]

    Sanyal, Sugata

    1 Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting Antonio Organization, Tata Consultancy Services, India. Abstract--Wireless energy harvesting sensor networks consti battery resource, but are able to re-charge themselves through directed electromagnetic energy transfer

  2. Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL

    E-Print Network [OSTI]

    Rubinstein, Benjamin

    Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL SENSOR technologies that may be combined into a cost effective soil redox sensor network, discuss the merits of each as a component of said network, describe a prototype soil redox sensor network and perform basic laboratory

  3. Cut-off Rate based Outage Probability Analysis of Frequency Hopping Mobile Radio under Jamming

    E-Print Network [OSTI]

    Yýlmaz, Özgür

    Cut-off Rate based Outage Probability Analysis of Frequency Hopping Mobile Radio under Jamming Conditions G¨okhan M. G¨uvensen Electrical and Electronics Eng. Dept. Middle East Technical University Ankara, Turkey Email: guvensen@metu.edu.tr Yalc¸in Tanik Electrical and Electronics Eng. Dept. Middle East

  4. Focused excimer laser initiated, radio frequency sustained high pressure air plasmas

    E-Print Network [OSTI]

    Scharer, John E.

    . One variant of the ICP reactor is the solenoidal type, having a helical coil wound around the side diameter helical radio frequency (RF) coil are presented. Quantum resonant multi-photon ionization (REMPI measurement of the gas pressure the electron temperature is obtained. Experiments show that the laser-formed

  5. Ultrasound radio-frequency time series for finding malignant breast lesions

    E-Print Network [OSTI]

    de Freitas, Nando

    -based solutions for breast lesion characterization to reduce the patient recall rate after mammography screening. In this work, ultrasound radio frequency time series analysis is performed for sepa- rating benign framework can help in differentiating malignant from benign breast lesions. 1 Introduction In the United

  6. Cathodoluminescence Study of GadoliniumDoped Yttrium Oxide Thin Films Deposited By RadioFrequency Magnetron Sputtering

    E-Print Network [OSTI]

    Fitz-Gerald, James M.

    Cathodoluminescence Study of Gadolinium­Doped Yttrium Oxide Thin Films Deposited By Radio­Frequency (001) substrate using radio­frequency magnetron sputtering. Alternating layers of Y2O3 and Gd wereA/cm2 . Non- radiative decay via thermal pathways is suspected for the observed activator saturation

  7. The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation

    E-Print Network [OSTI]

    Offringa, A R; Hurley-Walker, N; Kaplan, D L; Barry, N; Beardsley, A P; Bell, M E; Bernardi, G; Bowman, J D; Briggs, F; Callingham, J R; Cappallo, R J; Carroll, P; Deshpande, A A; Dillon, J S; Dwarakanath, K S; Ewall-Wice, A; Feng, L; For, B -Q; Gaensler, B M; Greenhill, L J; Hancock, P; Hazelton, B J; Hewitt, J N; Hindson, L; Jacobs, D C; Johnston-Hollitt, M; Kapi?ska, A D; Kim, H -S; Kittiwisit, P; Lenc, E; Line, J; Loeb, A; Lonsdale, C J; McKinley, B; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Morgan, J; Neben, A R; Oberoi, D; Ord, S M; Paul, S; Pindor, B; Pober, J C; Prabu, T; Procopio, P; Riding, J; Shankar, N Udaya; Sethi, S; Srivani, K S; Staveley-Smith, L; Subrahmanyan, R; Sullivan, I S; Tegmark, M; Thyagarajan, N; Tingay, S J; Trott, C M; Webster, R L; Williams, A; Williams, C L; Wu, C; Wyithe, J S; Zheng, Q

    2015-01-01T23:59:59.000Z

    The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array (SKA). We describe the automated radio-frequency interference (RFI) detection strategy implemented for the MWA, which is based on the AOFlagger platform, and present 72-231-MHz RFI statistics from 10 observing nights. RFI detection removes 1.1% of the data. RFI from digital TV (DTV) is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After RFI detection and excision, almost all data can be calibrated and imaged without further RFI mitigation efforts, including observations within the FM and DTV bands. The results are compared to a previously published Low-Frequency Array (LOFAR) RFI survey. The remote location of the MWA results in a substantially cleaner RFI environment compared to LOFAR's radio environment, but adequate detection of RFI is still required before data can be analysed. We include speci...

  8. Superconducting Radio Frequency Cavities as Axion Dark Matter Detectors

    E-Print Network [OSTI]

    P. Sikivie

    2013-01-20T23:59:59.000Z

    A modification of the cavity technique for axion dark matter detection is described in which the cavity is driven with input power instead of being permeated by a static magnetic field. A small fraction of the input power is pumped by the axion field to a receiving mode of frequency $\\omega_1$ when the resonance condition $\\omega_1 = \\omega_0 \\pm m_a$ is satisfied, where $\\omega_0$ is the frequency of the input mode and $m_a$ the axion mass. The relevant form factor is calculated for any pair of input and output modes in a cylindrical cavity. The overall search strategy is discussed and the technical challenges to be overcome by an actual experiment are listed.

  9. Radio-frequency probes of Antarctic ice at South Pole

    E-Print Network [OSTI]

    Besson, David Zeke; Kravchenko, I.

    2013-05-16T23:59:59.000Z

    the 1 1.5 2 2.5 3 3.5 4 0 200 400 600 800 1000 1200 1400 VS WR Frequency (MHz) Horn VSWR Tx SWRRx SWR Fig. 1. Voltage Standing Wave Ratio (VSWR) for both transmitter (Tx) and receiver (Rx) horn used for data taken at South Pole. signal... produce an azimuthal variation in echo strength. The Fresnel zone has a radial extent R roughly given by R ? ? 2?dTxdRx/(dTx + dRx)/2; using ??1 m and dTx ? dRx ?1000 m, we find R ?30 m. Nanosecond scale in- terference effects (the maximum allowed by Fig...

  10. Coupling effects in inductive discharges with radio frequency substrate biasing

    SciTech Connect (OSTI)

    Schulze, J.; Schuengel, E.; Czarnetzki, U.

    2012-01-09T23:59:59.000Z

    Low pressure inductively coupled plasmas (ICP) operated in neon at 27.12 MHz with capacitive substrate biasing (CCP) at 13.56 MHz are investigated by phase resolved optical emission spectroscopy, voltage, and current measurements. Three coupling mechanisms are found potentially limiting the separate control of ion energy and flux: (i) Sheath heating due to the substrate biasing affects the electron dynamics even at high ratios of ICP to CCP power. At fixed CCP power, (ii) the substrate sheath voltage and (iii) the amplitude as well as frequency of plasma series resonance oscillations of the RF current are affected by the ICP power.

  11. Multi-level RF identification system

    DOE Patents [OSTI]

    Steele, Kerry D.; Anderson, Gordon A.; Gilbert, Ronald W.

    2004-07-20T23:59:59.000Z

    A radio frequency identification system having a radio frequency transceiver for generating a continuous wave RF interrogation signal that impinges upon an RF identification tag. An oscillation circuit in the RF identification tag modulates the interrogation signal with a subcarrier of a predetermined frequency and modulates the frequency-modulated signal back to the transmitting interrogator. The interrogator recovers and analyzes the subcarrier signal and determines its frequency. The interrogator generates an output indicative of the frequency of the subcarrier frequency, thereby identifying the responding RFID tag as one of a "class" of RFID tags configured to respond with a subcarrier signal of a predetermined frequency.

  12. Identifications of FIRST radio sources in the NOAO Deep-Wide Field Survey

    E-Print Network [OSTI]

    K. EL Bouchefry; C. M. Cress

    2007-02-05T23:59:59.000Z

    In this paper we present the results of an optical and near infrared identification of 514 radio sources from the FIRST survey (Faint Images of the Radio Sky Survey at Twenty centimeters) with a flux-density limit of 1 mJy in the NOAO Deep-Wide Field Survey (NDWFS) Bootes field. Using optical (Bw, R, I) and K band data with approximate limits of Bw ~ 25.5mag, R ~ 25.8 mag, I ~25.5 mag and K~19.4 mag, optical counterparts have been identified for 378 of 514 FIRST radio sources. This corresponds to an identification rate of 34% in four bands (BwRIK), 60% in optical bands (BwRI) and 74% in I band. Photometric redshifts for these sources have been computed using the hyperz code. The inclusion of quasar template spectra in hyperz is investigated. We note that the photometric data are, in many cases, best matched to templates with very short star-formation timescales and the inferred ages of identified galaxies depend strongly on the assumptions about the star-formation timescale. The redshifts obtained are fairly consistent with those expected from the K-z relation for brighter radio sources but there is more scatter in the K-z diagram at z<1.

  13. FIRST SPECTROSCOPIC IMAGING OBSERVATIONS OF THE SUN AT LOW RADIO FREQUENCIES WITH THE MURCHISON WIDEFIELD ARRAY PROTOTYPE

    SciTech Connect (OSTI)

    Oberoi, Divya; Matthews, Lynn D.; Lonsdale, Colin J.; Benkevitch, Leonid [MIT Haystack Observatory, Westford, MA (United States); Cairns, Iver H.; Lobzin, Vasili [School of Physics, University of Sydney, Sydney (Australia); Emrich, David; Wayth, Randall B.; Arcus, Wayne [Curtin Institute for Radio Astronomy, Curtin University, Perth (Australia); Morgan, Edward H.; Williams, Christopher [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); Prabu, T.; Vedantham, Harish [Raman Research Institute, Bangalore (India); Williams, Andrew [Perth Observatory, The University of Western Australia, Perth (Australia); White, Stephen M. [Air Force Research Laboratory, Kirtland, NM (United States); Allen, G. [CSIRO Astronomy and Space Science, Epping, NSW (Australia); Barnes, David [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bernardi, Gianni [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, Judd D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Briggs, Frank H. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra (Australia)

    2011-02-20T23:59:59.000Z

    We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9- 201.6 MHz. Though our observing period is characterized as a period of 'low' to 'medium' activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal emission features are evident. Our data represent a significant advance in low radio frequency solar imaging, enabling us to follow the spatial, spectral, and temporal evolution of events simultaneously and in unprecedented detail. The rich variety of features seen here reaffirms the coronal diagnostic capability of low radio frequency emission and provides an early glimpse of the nature of radio observations that will become available as the next generation of low-frequency radio interferometers come online over the next few years.

  14. Characteristics of radio-frequency atmospheric pressure dielectric-barrier discharge with dielectric electrodes

    SciTech Connect (OSTI)

    Hussain, S., E-mail: shussain@uos.edu.pk, E-mail: shussainuos@yahoo.com; Qazi, H. I. A.; Badar, M. A. [Department of Physics, University of Sargodha, 40100 Sargodha (Pakistan)] [Department of Physics, University of Sargodha, 40100 Sargodha (Pakistan)

    2014-03-15T23:59:59.000Z

    An experimental investigation to characterize the properties and highlight the benefits of atmospheric pressure radio-frequency dielectric-barrier discharge (rf DBD) with dielectric electrodes fabricated by anodizing aluminium substrate is presented. The current-voltage characteristics and millisecond images are used to distinguish the ? and ? modes. This atmospheric rf DBD is observed to retain the discharge volume without constriction in ? mode. Optical emission spectroscopy demonstrates that the large discharge current leads to more abundant reactive species in this plasma source.

  15. Evolution of low-frequency contribution in emission of steep-spectrum radio sources

    E-Print Network [OSTI]

    Miroshnichenko, Alla

    2015-01-01T23:59:59.000Z

    We consider evolution properties of galaxies and quasars with steep radio spectrum at the decametre band from the UTR-2 catalogue. The ratios of source's monochromatic luminosities at the decametre and high-frequency bands display the dependence on the redshift, linear size, characteristic age of examined objects. At that, the mean values of corresponding ratios for considered galaxies and quasars have enough close quantities, testifying on the unified model of sources. We analyse obtained relations for two types of steep-spectrum sources (with linear steep spectrum (S) and low-frequency steepness after a break (C+)) from the UTR-2 catalogue.

  16. Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge

    SciTech Connect (OSTI)

    Shi, J. J.; Zhang, J.; Qiu, G. [College of Science, Donghua University, Shanghai 201620 (China); Walsh, J. L.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

    2008-07-28T23:59:59.000Z

    This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz, the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode, the discrete mode, and the transition mode. By investigating plasma ignition, residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density, gas temperature, optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

  17. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ciovati, Gianluigi; Baldwin, Charles; Cheng, Guangfeng; Flood, Roger; Jordan, Kevin; Kneisel, Peter; Morrone, Michael; Nemes, George; Turlington, Larry; Wang, Haipeng; Wilson, Katherine

    2012-03-16T23:59:59.000Z

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about one order of magnitude better than with earlier methods. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in details in this contribution.

  18. First Spectroscopic Imaging Observations of the Sun at Low Radio Frequencies with the Murchison Widefield Array Prototype

    E-Print Network [OSTI]

    Oberoi, Divya

    We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9–201.6 MHz. ...

  19. On the Carrier Frequency Offset Estimation for Frequency Hopping Burst Mode Mobile Radio

    E-Print Network [OSTI]

    Yýlmaz, �zgür

    for the transmission of one packet. Joint blind channel and CFO estimation over multiple frequency bursts is considered, achieves the joint CRB over multiple bursts. In the second part of the paper, some practical blind at each RFB and changes independently from block to block (block fading model [1]). Knowing

  20. Investigation of effect of excitation frequency on electron energy distribution functions in low pressure radio frequency bounded plasmas

    SciTech Connect (OSTI)

    Bhattacharjee, Sudeep [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India); Lafleur, Trevor; Charles, Christine; Boswell, Rod [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2011-07-15T23:59:59.000Z

    Particle in cell (PIC) simulations are employed to investigate the effect of excitation frequency {omega} on electron energy distribution functions (EEDFs) in a low pressure radio frequency (rf) discharge. The discharge is maintained over a length of 0.10 m, bounded by two infinite parallel plates, with the coherent heating field localized at the center of the discharge over a distance of 0.05 m and applied perpendicularly along the y and z directions. On varying the excitation frequency f (={omega}/2{pi}) in the range 0.01-50 MHz, it is observed that for f {<=} 5 MHz the EEDF shows a trend toward a convex (Druyvesteyn-like) distribution. For f > 5 MHz, the distribution resembles more like a Maxwellian with the familiar break energy visible in most of the distributions. A prominent ''hot tail'' is observed at f{>=} 20 MHz and the temperature of the tail is seen to decrease with further increase in frequency (e.g., at 30 MHz and 50 MHz). The mechanism for the generation of the ''hot tail'' is considered to be due to preferential transit time heating of energetic electrons as a function of {omega}, in the antenna heating field. There exists an optimum frequency for which high energy electrons are maximally heated. The occurrence of the Druyvesteyn-like distributions at lower {omega} may be explained by a balance between the heating of the electrons in the effective electric field and elastic cooling due to electron neutral collision frequency {nu}{sub en}; the transition being dictated by {omega} {approx} 2{pi}{nu}{sub en}.

  1. Augmenting real data with synthetic data: an application in assessing radio-isotope identification algorithms

    SciTech Connect (OSTI)

    Burr, Tom L [Los Alamos National Laboratory; Hamada, Michael [Los Alamos National Laboratory; Graves, Todd [Los Alamos National Laboratory; Myers, Steve [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    The performance of Radio-Isotope Identification (RIID) algorithms using gamma spectroscopy is increasingly important. For example, sensors at locations that screen for illicit nuclear material rely on isotope identification to resolve innocent nuisance alarms arising from naturally occurring radioactive material. Recent data collections for RIID testing consist of repeat measurements for each of several scenarios to test RIID algorithms. Efficient allocation of measurement resources requires an appropriate number of repeats for each scenario. To help allocate measurement resources in such data collections for RIID algorithm testing, we consider using only a few real repeats per scenario. In order to reduce uncertainty in the estimated RIID algorithm performance for each scenario, the potential merit of augmenting these real repeats with realistic synthetic repeats is also considered. Our results suggest that for the scenarios and algorithms considered, approximately 10 real repeats augmented with simulated repeats will result in an estimate having comparable uncertainty to the estimate based on using 60 real repeats.

  2. Radio-frequency induced ground state degeneracy in a Chromium Bose-Einstein condensate

    E-Print Network [OSTI]

    Q. Beaufils; T. Zanon; R. Chicireanu; B. Laburthe-Tolra; E. Marechal; L. Vernac; J. -C. Keller; O. Gorceix

    2008-09-29T23:59:59.000Z

    We study the effect of strong radio-frequency (rf) fields on a chromium Bose-Einstein condensate (BEC), in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\\'{e} factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to 100 mG. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong field regime. We investigate the problem of adiabaticity of the rf dressing process, and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs, and identify a new rf-assisted two-body loss process induced by dipole-dipole interactions.

  3. On the application of radio frequency voltages to ion traps via helical resonators

    E-Print Network [OSTI]

    J. D. Siverns; L. R. Simkins; S. Weidt; W. K. Hensinger

    2011-10-18T23:59:59.000Z

    Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.

  4. MULTI-FREQUENCY STUDIES OF RADIO RELICS IN THE GALAXY CLUSTERS A4038, A1664, AND A786

    SciTech Connect (OSTI)

    Kale, Ruta; Dwarakanath, K. S., E-mail: ruta@iucaa.ernet.in [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080 (India)

    2012-01-01T23:59:59.000Z

    We present a multi-frequency study of radio relics associated with the galaxy clusters A4038, A1664, and A786. Radio images, integrated spectra, spectral index maps, and fits to the integrated spectra in the framework of the adiabatic compression model are presented. Images of the relic in A4038 at 150, 240, and 606 MHz with the Giant Meterwave Radio Telescope have revealed extended ultra-steep spectrum ({alpha} {approx} -1.8 to -2.7) emission of extent 210 Multiplication-Sign 80 kpc{sup 2}. The model of passively evolving radio lobes compressed by a shock fits the integrated spectrum best. The relic with a circular morphology at the outskirts of the cluster A1664 has an integrated spectral index of {approx} - 1.10 {+-} 0.06 and is best fit by the model of radio lobes lurking for {approx}4 Multiplication-Sign 10{sup 7} yr. The relic near A786 has a curved spectrum and is best fit by a model of radio lobes lurking for {approx}3 Multiplication-Sign 10{sup 7} yr. At 4.7 GHz, a compact radio source, possibly the progenitor of the A786 relic, is detected near the center of the radio relic. The A786 radio relic is thus likely a lurking radio galaxy rather than a site of cosmological shock as has been considered in earlier studies.

  5. Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials

    DOE Patents [OSTI]

    Johnston, Steven W. (Golden, CO); Ahrenkiel, Richard K. (Lakewood, CO)

    2002-01-01T23:59:59.000Z

    An apparatus for measuring the minority carrier lifetime of a semiconductor sample using radio-frequency coupling. The measuring apparatus includes an antenna that is positioned a coupling distance from a semiconductor sample which is exposed to light pulses from a laser during sampling operations. A signal generator is included to generate high frequency, such as 900 MHz or higher, sinusoidal waveform signals that are split into a reference signal and a sample signal. The sample signal is transmitted into a sample branch circuit where it passes through a tuning capacitor and a coaxial cable prior to reaching the antenna. The antenna is radio-frequency coupled with the adjacent sample and transmits the sample signal, or electromagnetic radiation corresponding to the sample signal, to the sample and receives reflected power or a sample-coupled-photoconductivity signal back. To lower impedance and speed system response, the impedance is controlled by limiting impedance in the coaxial cable and the antenna reactance. In one embodiment, the antenna is a waveguide/aperture hybrid antenna having a central transmission line and an adjacent ground flange. The sample-coupled-photoconductivity signal is then transmitted to a mixer which also receives the reference signal. To enhance the sensitivity of the measuring apparatus, the mixer is operated to phase match the reference signal and the sample-coupled-photoconductivity signal.

  6. Radio Frequency Surface Impedance Characterization System for Superconducting Samples at 7.5 GHz

    SciTech Connect (OSTI)

    Binping Xiao, Charles Reece, Michael Kelley, Larry Phillips, Rongli Geng, Haipeng Wang, Frank Marhauser

    2011-05-01T23:59:59.000Z

    A radio frequency (RF) surface impedance characterization (SIC) system that uses a sapphire-loaded Nb cavity operating at 7.5 GHz has been fabricated to measure the RF surface impedance of flat superconducting samples. Currently, the SIC system can make direct calorimetric surface impedance measurements in the central 0.8 cm2 area of 5 cm diameter disk samples in a temperature range from 2 to 20 K, exposed to a magnetic flux density of up to 14 mT. As an application, we present the measurement results for a bulk Nb sample.

  7. Tuning the work function of graphene by nitrogen plasma treatment with different radio-frequency powers

    SciTech Connect (OSTI)

    Zeng, Jian-Jhou; Lin, Yow-Jon, E-mail: rzr2390@yahoo.com.tw [Institute of Photonics, National Changhua University of Education, Changhua 500, Taiwan (China)

    2014-06-09T23:59:59.000Z

    Graphene prepared by the chemical vapor deposition method was treated with nitrogen plasma under different radio-frequency (rf) power conditions in order to experimentally study the change in the work function. Control of the rf power could change the work function of graphene from 4.91?eV to 4.37?eV. It is shown that the increased rf power may lead to the increased number of graphitic nitrogen, increasing the electron concentration, and shifting the Fermi level to higher energy. The ability to controllably tune the work function of graphene is essential for optimizing the efficiency of optoelectronic and electronic devices.

  8. Radio Frequency Phototube, Optical Clock and Precise Measurements in Nuclear Physics

    E-Print Network [OSTI]

    Amur Margaryan

    2009-10-24T23:59:59.000Z

    Recently a new experimental program of novel systematic studies of light hypernuclei using pionic decay was established at JLab (Study of Light Hypernuclei by Pionic Decay at JLab, JLab Experiment PR-08-012). The highlights of the proposed program include high precision measurements of binding energies of hypernuclei by using a high resolution pion spectrometer, HpiS. The average values of binding energies will be determined within an accuracy of ~10 keV or better. Therefore, the crucial point of this program is an absolute calibration of the HpiS with accuracy 10E-4 or better. The merging of continuous wave laser-based precision optical-frequency metrology with mode-locked ultrafast lasers has led to precision control of the visible frequency spectrum produced by mode-locked lasers. Such a phase-controlled mode-locked laser forms the foundation of an optical clock or femtosecond optical frequency comb (OFC) generator, with a regular comb of sharp lines with well defined frequencies. Combination of this technique with a recently developed radio frequency (RF) phototube results in a new tool for precision time measurement. We are proposing a new time-of-flight (TOF) system based on an RF phototube and OFC technique. The proposed TOF system achieves 10 fs instability level and opens new possibilities for precise measurements in nuclear physics such as an absolute calibration of magnetic spectrometers within accuracy 10E-4 - 10E-5.

  9. Spin-torque diode radio-frequency detector with voltage tuned resonance

    SciTech Connect (OSTI)

    Skowro?ski, Witold, E-mail: skowron@agh.edu.pl; Frankowski, Marek; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Wrona, Jerzy [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Singulus Technologies, Kahl am Main 63796 (Germany); Ogrodnik, Piotr [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Barna?, Józef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Pozna? (Poland); Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Pozna? (Poland)

    2014-08-18T23:59:59.000Z

    We report on a voltage-tunable radio-frequency (RF) detector based on a magnetic tunnel junction (MTJ). The spin-torque diode effect is used to excite and/or detect RF oscillations in the magnetic free layer of the MTJ. In order to reduce the overall in-plane magnetic anisotropy of the free layer, we take advantage of the perpendicular magnetic anisotropy at the interface between ferromagnetic and insulating layers. The applied bias voltage is shown to have a significant influence on the magnetic anisotropy, and thus on the resonance frequency of the device. This influence also depends on the voltage polarity. The obtained results are accounted for in terms of the interplay of spin-transfer-torque and voltage-controlled magnetic anisotropy effects.

  10. Nitrogen heat treatments of superconducting niobium radio frequency cavities: a pathway to highly efficient accelerating structures

    E-Print Network [OSTI]

    Grassellino, A; Melnychuk, O; Trenikhina, Y; Crawford, A; Rowe, A; Wong, M; Sergatskov, D; Khabiboulline, T; Barkov, F

    2013-01-01T23:59:59.000Z

    We report the experimental finding of a new surface treatment that systematically improves the quality factor of niobium radio frequency cavities for particle acceleration. A combination of annealing in a partial pressure of nitrogen and subsequent electropolishing of the niobium cavity surface leads to extremely low values of the cavities microwave surface resistance, and an improvement in the efficiency of these accelerating structures up to a factor of 3 compared to standard surface treatments, significantly reducing the cryogenic load of SRF cavities for both pulsed and continuous duty cycles. The field dependence of the Mattis-Bardeen/BCS surface resistance RBCS is reversed compared to that of standard chemically polished niobium with dRBCS/dB < 0 in the full range of investigated fields. This treatment can lead to even larger efficiency gains at increasing operating frequencies, and potentially to even larger cost savings by reducing the size of the accelerating structures.

  11. Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls

    SciTech Connect (OSTI)

    Inada, Y., E-mail: inada@hvg.t.u-tokyo.ac.jp; Abe, K.; Kumada, A.; Hidaka, K. [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Amano, K.; Itoh, K.; Oono, T. [R and D Center, Tokyo Electric Power Company, 4-1 Egasaki-cho, Tsurumi-ku, Yokohama 230-8510 (Japan)

    2014-10-27T23:59:59.000Z

    It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H{sup +}, while those produced in the other solutions were mainly H.

  12. Damage mechanisms identification of polymer based composite materials: time-frequency investigation of

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Damage mechanisms identification of polymer based composite materials: time-frequency investigation 2012, Nantes, France 2045 #12;Presented in this paper, a time-frequency damage characterization Emission (AE) signals by the Hilbert-Huang transform (HHT). It is to be noted that the study of damage

  13. Survey of ambient electromagnetic and radio-frequency interference levels in nuclear power plants

    SciTech Connect (OSTI)

    Kercel, S.W.; Moore, M.R.; Blakeman, E.D.; Ewing, P.D.; Wood, R.T.

    1996-11-01T23:59:59.000Z

    This document reports the results of a survey of ambient electromagnetic conditions in representative nuclear power plants. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research engaged the Oak Ridge National Laboratory (ORNL) to perform these measurements to characterize the electromagnetic interference (EMI) and radio-frequency interference (RFI) levels that can be expected in nuclear power plant environments. This survey is the first of its kind, being based on long-term unattended observations. The data presented in this report were measured at eight different nuclear units and required 14 months to collect. A representative sampling of power plant conditions (reactor type, operating mode, site location) monitored over extended observation periods (up to 5 weeks) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. Radiated electric fields were measured over the frequency range of 5 MHz to 8 GHz. Radiated magnetic fields and conducted EMI events were measured over the frequency range of 305 Hz to 5 MHz. Highest strength observations of the electromagnetic ambient environment across all measurement conditions at each site provide frequency-dependent profiles for EMI/RFI levels in nuclear power plants.

  14. Noninvasive identification of fluids by swept-frequency acoustic interferometry

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM)

    1998-01-01T23:59:59.000Z

    A method for rapid, noninvasive identification and monitoring of chemicals in sealed containers or containers where direct access to the chemical is not possible is described. Multiple ultrasonic acoustic properties (up to four) of a fluid are simultaneously determined. The present invention can be used for chemical identification and for determining changes in known chemicals from a variety of sources. It is not possible to identify all known chemicals based on the measured parameters, but known classes of chemicals in suspected containers, such as in chemical munitions, can be characterized. In addition, a large number of industrial chemicals can be identified.

  15. The Standing Wave Phenomenon in Radio Telescopes; Frequency Modulation of the WSRT Primary Beam

    E-Print Network [OSTI]

    Attila Popping; Robert Braun

    2007-12-14T23:59:59.000Z

    Inadequacies in the knowledge of the primary beam response of current interferometric arrays often form a limitation to the image fidelity. We hope to overcome these limitations by constructing a frequency-resolved, full-polarization empirical model for the primary beam of the Westerbork Synthesis Radio Telescope (WSRT). Holographic observations, sampling angular scales between about 5 arcmin and 11 degrees, were obtained of a bright compact source (3C147). These permitted measurement of voltage response patterns for seven of the fourteen telescopes in the array and allowed calculation of the mean cross-correlated power beam. Good sampling of the main-lobe, near-in, and far-side-lobes out to a radius of more than 5 degrees was obtained. A robust empirical beam model was detemined in all polarization products and at frequencies between 1322 and 1457 MHz with 1 MHz resolution. Substantial departures from axi-symmetry are apparent in the main-lobe as well as systematic differences between the polarization properties. Surprisingly, many beam properties are modulated at the 5 to 10% level with changing frequency. These include: (1) the main beam area, (2) the side-lobe to main-lobe power ratio, and (3) the effective telescope aperture. These semi-sinusoidsal modulations have a basic period of about 17 MHz, consistent with the natural 'standing wave' period of a 8.75 m focal distance. The deduced frequency modulations of the beam pattern were verified in an independent long duration observation using compact continuum sources at very large off-axis distances. Application of our frequency-resolved beam model should enable higher dynamic range and improved image fidelity for interferometric observations in complex fields. (abridged)

  16. Influence of finite geometrical asymmetry of the electrodes in capacitively coupled radio frequency plasma

    SciTech Connect (OSTI)

    Bora, B., E-mail: bbora@cchen.cl; Soto, L. [Comisión Chilena de Energía Nuclear, Santiago, Chile and Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile)

    2014-08-15T23:59:59.000Z

    Capacitively coupled radio frequency (CCRF) plasmas are widely studied in last decades due to the versatile applicability of energetic ions, chemically active species, radicals, and also energetic neutral species in many material processing fields including microelectronics, aerospace, and biology. A dc self-bias is known to generate naturally in geometrically asymmetric CCRF plasma because of the difference in electrode sizes known as geometrical asymmetry of the electrodes in order to compensate electron and ion flux to each electrode within one rf period. The plasma series resonance effect is also come into play due to the geometrical asymmetry and excited several harmonics of the fundamental in low pressure CCRF plasma. In this work, a 13.56?MHz CCRF plasma is studied on the based on the nonlinear global model of asymmetric CCRF discharge to understand the influences of finite geometrical asymmetry of the electrodes in terms of generation of dc self-bias and plasma heating. The nonlinear global model on asymmetric discharge has been modified by considering the sheath at the grounded electrode to taking account the finite geometrical asymmetry of the electrodes. The ion density inside both the sheaths has been taken into account by incorporating the steady-state fluid equations for ions considering that the applied rf frequency is higher than the typical ion plasma frequency. Details results on the influences of geometrical asymmetry on the generation of dc self-bias and plasma heating are discussed.

  17. High power water load for microwave and millimeter-wave radio frequency sources

    DOE Patents [OSTI]

    Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

    1999-01-01T23:59:59.000Z

    A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

  18. Coupled microwave ECR and radio-frequency plasma source for plasma processing

    DOE Patents [OSTI]

    Tsai, C.C.; Haselton, H.H.

    1994-03-08T23:59:59.000Z

    In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm[sup 2] at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance. 4 figures.

  19. Coupled microwave ECR and radio-frequency plasma source for plasma processing

    DOE Patents [OSTI]

    Tsai, Chin-Chi (Oak Ridge, TN); Haselton, Halsey H. (Knoxville, TN)

    1994-01-01T23:59:59.000Z

    In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm.sup.2 at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance.

  20. Feasibility study of a decelerating radio frequency quadrupole system for the antiproton decelerator AD

    E-Print Network [OSTI]

    Bosser, Jacques; Brouet, M; Couturier, B; Gelato, G; Giovannozzi, Massimo; Grandclaude, F; Hémery, J Y; Lombardi, A M; Mikkelsen, U; Maury, S; Möhl, D; Pedersen, F; Pirkl, Werner; Raich, U; Umstätter, H H; Vretenar, Maurizio

    1998-01-01T23:59:59.000Z

    This feasibility study reports on a decelerating Radio-Frequency Quadrupole (RFQ) system for post-deceleration of the 100 MeV/c antiproton beam of the AD machine. The corresponding kinetic energy of 5.314 MeV is reduced to values which can be chosen between 10 to 100 keV with minimal blow-up of the normalised beam emittances. This wide range of output energy is required for the second phase of the ASACUSA experiment; it is achieved by electrostatic means. The study gives details of the overall performance of the system, the proposed implementation of the RFQ, the associated rf equipment, the beam lines, the diagnostics as well as estimations for the cost and the manpower requirements of the project.

  1. Supersonic combustion of a transverse injected H sub 2 jet in a radio frequency heated flow

    SciTech Connect (OSTI)

    Wantuck, P.J.; Tennant, R.A.; Watanabe, H.H.

    1991-01-01T23:59:59.000Z

    The combustion of a single hydrogen jet, normally injected into a radio frequency (RF) heated, oxidant-containing, supersonic flow, has been established to characterize the chemical and fluid dynamic phenomena associated with the reaction process and ultimately validate the predictive capability of computational computer dynamic (CFD) codes. The experimental system employed for this study is unique in that it uses an electrodeless, inductively coupled plasma tube to generate the high temperature oxidant-containing gas for subsequent nozzle expansion. Advantages of an RF heated flow system include reduced free-stream chemical contamination, continuous operation, and relative ease of integration into a typical flow laboratory environment. A description of the system utilized for this study is presented including preliminary results of the reactive flow characterization. In addition, the use of the laser-based diagnostic techniques, such as planar laser-induced fluorescence (PLIF), for measuring flow properties is also discussed. 8 refs., 7 figs.

  2. Surface Science Laboratory for Studying the Surfaces of Superconducting Radio Frequency Cavities

    SciTech Connect (OSTI)

    Andy Wu

    2003-09-01T23:59:59.000Z

    A Surface Science Laboratory (SSL) has been established at JLab to study surfaces relevant to superconducting radio frequency (SRF) cavities. Current operational facilities include a scanning electron microscope equipped with energy dispersive x-ray analysis, a secondary ion mass spectrometry, a metallographic optical microscope, a transmission electron microscope, a high precision and large scan area 3-D profilometer, a scanning field emission microscope, and a fully equipped sample preparation room. A scanning Auger microscope is being commissioned, and will be available for routine usage soon. Results from typical examples of the R&D projects on SRF cavities that were supported in the past through the use of the facilities in the SSL will be briefly reported.

  3. Motion of free spins and NMR imaging without a radio-frequency magnetic field

    E-Print Network [OSTI]

    Kees van Schenk Brill; Jassem Lahfadi; Tarek Khalil; Daniel Grucker

    2015-04-19T23:59:59.000Z

    NMR imaging without any radio-frequency magnetic field is explained by a quantum treatment of independent spin~$\\tfrac 12$. The total magnetization is determined by means of their individual wave function. The theoretical treatment, based on fundamental axioms of quantum mechanics and solving explicitly the Schr\\"{o}dinger equation with the kinetic energy part which gives the motion of free spins, is recalled. It explains the phase shift of the spin noise spectrum with its amplitude compared to the conventional NMR spectrum. Moreover it explains also the relatively good signal to noise ratio of NMR images obtained without a RF pulse. This derivation should be helpful for new magnetic resonance imaging sequences or for developing quantum computing by NMR.

  4. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    SciTech Connect (OSTI)

    W. M. Roach, D. B. Beringer, J. R. Skuza, W. A. Oliver, C. Clavero, C. E. Reece, R. A. Lukaszew

    2012-06-01T23:59:59.000Z

    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

  5. Laser polishing of niobium for superconducting radio-frequency accelerator applications

    SciTech Connect (OSTI)

    Zhao, Liang [William and Mary College; Klopf, John M. [William and Mary College; Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB

    2014-08-01T23:59:59.000Z

    Interior surfaces of niobium cavities used in superconducting radio frequency accelerators are now obtained by buffered chemical polish and/or electropolish. Laser polishing is a potential alternative, having advantages of speed, freedom from noxious chemistry and availability of in-process inspection. We studied the influence of the laser power density and laser beam raster rate on the surface topography. These two factors need to be combined carefully to smooth the surface without damage. Computational modeling was used to estimate the surface temperature and gain insight into the mechanism of laser polishing. Power spectral density analysis of surface topography measurements shows that laser polishing can produce smooth topography similar to that obtained by electropolish. This is a necessary first step toward introducing laser polishing as an alternative to the currently practiced chemical polishing.

  6. Verification of particle simulation of radio frequency waves in fusion plasmas

    SciTech Connect (OSTI)

    Kuley, Animesh; Lin, Z. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States) [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Fusion Simulation Center, Peking University, Beijing 100871 (China); Wang, Z. X. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)] [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Wessel, F. [Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States)] [Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2013-10-15T23:59:59.000Z

    Radio frequency (RF) waves can provide heating, current and flow drive, as well as instability control for steady state operations of fusion experiments. A particle simulation model has been developed in this work to provide a first-principles tool for studying the RF nonlinear interactions with plasmas. In this model, ions are considered as fully kinetic particles using the Vlasov equation and electrons are treated as guiding centers using the drift kinetic equation. This model has been implemented in a global gyrokinetic toroidal code using real electron-to-ion mass ratio. To verify the model, linear simulations of ion plasma oscillation, ion Bernstein wave, and lower hybrid wave are carried out in cylindrical geometry and found to agree well with analytic predictions.

  7. Flux pinning characteristics in cylindrical ingot niobium used in superconducting radio frequency cavity fabrication

    SciTech Connect (OSTI)

    Dhavale Ashavai, Pashupati Dhakal, Anatolii A Polyanskii, Gianluigi Ciovati

    2012-04-01T23:59:59.000Z

    We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples which implies a lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.

  8. Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole

    SciTech Connect (OSTI)

    Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Sha, Sh.; Zhang, Zh. L.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-07-15T23:59:59.000Z

    The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

  9. Push-pull radio frequency circuit with integral transistion to waveguide output

    DOE Patents [OSTI]

    Bennett, Wilfred P. (21 Catskill Ct., Belle Mead, NJ 08502)

    1987-01-01T23:59:59.000Z

    A radio frequency circuit for ICRF heating includes a resonant push-pull circuit, a double ridged rectangular waveguide, and a coupling transition which joins the waveguide to the resonant circuit. The resonant circuit includes two cylindrical conductors mounted side by side and two power vacuum tubes attached to respective ends of a cylindrical conductor. A conductive yoke is located at the other end of the cylindrical conductors to short circuit the two cylindrical conductors. The coupling transition includes two relatively flat rectangular conductors extending perpendicular to the longitudinal axes of a respective cylindrical conductor to which the flat conductor is attached intermediate the ends thereof. Conductive side covers and end covers are also provided for forming pockets in the waveguide into which the flat conductors extend when the waveguide is attached to a shielding enclosure surrounding the resonant circuit.

  10. Nanostructural features affecting superconducting radio frequency niobium cavities revealed using TEM and EELS

    E-Print Network [OSTI]

    Trenikhina, Y; Kwon, J; Zuo, J -M; Zasadzinski, J F

    2015-01-01T23:59:59.000Z

    Nanoscale defect structure within the magnetic penetration depth of ~100nm is key to the performance limitations of niobium superconducting radio frequency (SRF) cavities. Using a unique combination of advanced thermometry during cavity RF measurements, and TEM structural and compositional characterization of the samples extracted from cavity walls, we discover the existence of nanoscale hydrides in electropolished cavities limited by the high field Q slope, and show the decreased hydride formation in the electropolished cavity after 120C baking. Furthermore, we demonstrate that adding 800C hydrogen degassing followed by light buffered chemical polishing restores the hydride formation to the pre-120C bake level. We also show absence of niobium oxides along the grain boundaries and the modifications of the surface oxide upon 120C bake.

  11. DERIVATION OF THE MAGNETIC FIELD IN A CORONAL MASS EJECTION CORE VIA MULTI-FREQUENCY RADIO IMAGING

    SciTech Connect (OSTI)

    Tun, Samuel D. [The Naval Research Laboratory, Washington, DC 20375 (United States)] [The Naval Research Laboratory, Washington, DC 20375 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2013-04-01T23:59:59.000Z

    The magnetic field within the core of a coronal mass ejection (CME) on 2010 August 14 is derived from analysis of multi-wavelength radio imaging data. This CME's core was found to be the source of a moving type IV radio burst, whose emission is here determined to arise from the gyrosynchrotron process. The CME core's true trajectory, electron density, and line-of-sight depth are derived from stereoscopic observations, constraining these parameters in the radio emission models. We find that the CME carries a substantial amount of mildly relativistic electrons (E < 100 keV) in a strong magnetic field (B < 15 G), and that the spectra at lower heights are preferentially suppressed at lower frequencies through absorption from thermal electrons. We discuss the results in light of previous moving type IV burst studies, and outline a plan for the eventual use of radio methods for CME magnetic field diagnostics.

  12. Self-consistent modeling of radio-frequency plasma generation in stellarators

    SciTech Connect (OSTI)

    Moiseenko, V. E., E-mail: moiseenk@ipp.kharkov.ua; Stadnik, Yu. S., E-mail: stadnikys@kipt.kharkov.ua [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine); Lysoivan, A. I., E-mail: a.lyssoivan@fz-juelich.de [Royal Military Academy, EURATOM-Belgian State Association, Laboratory for Plasma Physics (Belgium); Korovin, V. B. [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)] [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)

    2013-11-15T23:59:59.000Z

    A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell’s equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell’s equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell’s equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell’s equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

  13. Radial electric field generated by resonant trapped electron pinch with radio frequency injection in a tokamak plasma

    E-Print Network [OSTI]

    Radial electric field generated by resonant trapped electron pinch with radio frequency injection of Modern Physics, University of Science and Technology of China, Hefei 230026, China (Received 10 May 2011 by charge accumulation due to a resonant trapped electron pinch effect. The radial field can then drive

  14. I. Standard Configuration The Radio Frequency Fragment Separator (RFFS) is a filtering device intended to enhance the

    E-Print Network [OSTI]

    to stop the ions in the last detector, so that gamma-rays emitted shortly after implantation canI. Standard Configuration A. General The Radio Frequency Fragment Separator (RFFS) is a filtering device intended to enhance the purity of radioactive beams produced via projectile fragmentation

  15. 3742 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 47, NO. 11, NOVEMBER 2009 Microwave Radiometer Radio-Frequency

    E-Print Network [OSTI]

    Ruf, Christopher

    Radiometer Radio-Frequency Interference Detection Algorithms: A Comparative Study Sidharth Misra, Priscilla N is with Halliburton Energy Services, Houston, TX 77032 USA. J. R. Piepmeier is with the Microwave Instrument growth recently in satellite telecommunica- tion, in high-bandwidth point-to-point terrestrial wireless

  16. Design of multi-channel radio-frequency front-end for 200mhz parallel magnetic resonance imaging

    E-Print Network [OSTI]

    Liu, Xiaoqun

    2009-05-15T23:59:59.000Z

    increases to 64 or even 128, the traditional method of stacking the same number of radio-frequency (RF) receivers with very low level of integration becomes expensive and cumbersome. However, the cost, size, power consumption of the Parallel MRI receivers...

  17. Simulation of a two-dimensional sheath over a flat insulatorconductor interface on a radio-frequency biased electrode in a high-density plasma

    E-Print Network [OSTI]

    Economou, Demetre J.

    Simulation of a two-dimensional sheath over a flat insulator­conductor interface on a radio-frequency the two-dimensional 2D sheath over a flat insulator/conductor interface on a radio-frequency rf biased is no longer one dimen- sional. The extent of sheath ``disturbance'' depends on the thickness of the sheath

  18. System efficiency analysis for high power solid state radio frequency transmitter

    SciTech Connect (OSTI)

    Jain, Akhilesh, E-mail: ajain@rrcat.gov.in; Sharma, D. K.; Gupta, A. K.; Lad, M. R.; Hannurkar, P. R. [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Pathak, S. K. [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)] [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)

    2014-02-15T23:59:59.000Z

    This paper examines some important relationships, related with the system efficiency, for very high power, radio frequency solid-state transmitter; incorporating multiple solid-state power amplifier modules, power combiners, dividers, couplers, and control/interlock hardware. In particular, the characterization of such transmitters, at the component as well as the system level, is discussed. The analysis for studying the influence of the amplitude and phase imbalance, on useful performance parameters like system efficiency and power distribution is performed. This analysis is based on a scattering parameter model. This model serves as a template for fine-tuning the results, with the help of a system level simulator. For experimental study, this approach is applied to a recently designed modular and scalable solid-state transmitter, operating at the centre frequency of 505.8?MHz and capable of delivering a continuous power of 75 kW. Such first time presented, system level study and experimental characterization for the real time operation will be useful for the high power solid-state amplifier designs, deployed in particle accelerators.

  19. Radio-frequency driven dipole-dipole interactions in spatially separated volumes

    E-Print Network [OSTI]

    Atreju Tauschinsky; C. S. E. van Ditzhuijzen; L. D. Noordam; H. B. van Linden van den Heuvell

    2008-10-14T23:59:59.000Z

    Radio-frequency (rf) fields in the MHz range are used to induce resonant energy transfer between cold Rydberg atoms in spatially separated volumes. After laser preparation of the Rydberg atoms, dipole-dipole coupling excites the 49s atoms in one cylinder to the 49p state while the 41d atoms in the second cylinder are transferred down to the 42p state. The energy exchanged between the atoms in this process is 33 GHz. An external rf-field brings this energy transfer into resonance. The strength of the interaction has been investigated as a function of amplitude (0-1 V/cm) and frequency (1-30 MHz) of the rf-field and as a function of a static field offset. Multi-photon transitions up to fifth order as well as selection rules prohibiting the process at certain fields have been observed. The width of the resonances has been reduced compared to earlier results by switching off external magnetic fields of the magneto-optical trap, making sub-MHz spectroscopy possible. All features are well reproduced by theoretical calculations taking the strong ac-Stark shift due to the rf-field into account.

  20. Electromagnetic and mechanical design of gridded radio-frequency cavity windows

    SciTech Connect (OSTI)

    Alsharo'a, Mohammad M.

    2004-12-01T23:59:59.000Z

    Electromagnetic, thermal and structural analyses of radio-frequency (RF) cavities were performed as part of a developmental RF cavity program for muon cooling. RF cavities are necessary to provide longitudinal focusing of the muons and to compensate for their energy loss. Closing the cavity ends by electrically conducting windows reduces the power requirement and increases the on-axis electric field for a given maximum surface electric field. Many factors must be considered in the design of RF cavity windows. RF heating can cause the windows to deform in the axial direction of the cavity. The resulting thermal stresses in the window must be maintained below the yield stress of the window material. The out-of-plane deflection must be small enough so that the consequent frequency shift is tolerable. For example, for an 805 MHz cavity, the out-of-plane deflection must be kept below 25 microns to prevent the frequency of the cavity from shifting more than 10 kHz. In addition, the window design should yield smooth electric and magnetic fields, terminate field leakage beyond the window, and minimize beam scattering. In the present thesis, gridded-tube window designs were considered because of their high structural integrity. As a starting point in the analysis, a cylindrical pillbox cavity was considered as a benchmark problem. Analytical and finite element solutions were obtained for the electric and magnetic fields, power loss density, and temperature profile. Excellent agreement was obtained between the analytical and finite element results. The finite element method was then used to study a variety of gridded-tube windows. It was found that cooling of the gridded-tube windows by passing helium gas inside the tubes significantly reduces the out-of-plane deflection and the thermal stresses. Certain tube geometries and grid patterns were found to satisfy all of the design requirements.

  1. Damage Identification for Bridges Using Frequency and Time Domain Data Amir Ardalan Mosavi1

    E-Print Network [OSTI]

    Damage Identification for Bridges Using Frequency and Time Domain Data Amir Ardalan Mosavi1 Error predictions of the ARX model x , y Standard deviations of the prediction errors DF,H , DF,D Damage Features calculated for healthy and damaged conditions of the structure f(DF,H) , g(DF,D) Probability

  2. DAMAGE IDENTIFICATION IN A STEEL FRAME USING HIGH-FREQUENCY ELECTRO-MECHANICAL IMPEDANCE

    E-Print Network [OSTI]

    Wang, Ji

    411 DAMAGE IDENTIFICATION IN A STEEL FRAME USING HIGH-FREQUENCY ELECTRO-MECHANICAL IMPEDANCE presents an experimental investigation of damage detection of a steel frame using electro damage in structures. Damages are introduced by completely loosening bolts over several locations

  3. THE SUB-mJy RADIO POPULATION OF THE E-CDFS: OPTICAL AND INFRARED COUNTERPART IDENTIFICATION

    SciTech Connect (OSTI)

    Bonzini, M.; Mainieri, V.; Padovani, P.; Rosati, P. [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Kellermann, K. I. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Miller, N. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Tozzi, P.; Balestra, I. [INAF Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, I-34131, Trieste (Italy); Vattakunnel, S. [Dipartimento di Fisica Universit di Trieste, piazzale Europa 1, I-34127 Trieste (Italy); Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Xue, Y. Q., E-mail: mbonzini@eso.org [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)

    2012-11-15T23:59:59.000Z

    We study a sample of 883 sources detected in a deep Very Large Array survey at 1.4 GHz in the Extended Chandra Deep Field South. This paper focuses on the identification of their optical and infrared (IR) counterparts. We use a likelihood-ratio technique that is particularly useful when dealing with deep optical images to minimize the number of spurious associations. We find a reliable counterpart for 95% of our radio sources. Most of the counterparts (74%) are detected at optical wavelengths, but there is a significant fraction (21%) that are only detectable in the IR. Combining newly acquired optical spectra with data from the literature, we are able to assign a redshift to 81% of the identified radio sources (37% spectroscopic). We also investigate the X-ray properties of the radio sources using the Chandra 4 Ms and 250 ks observations. In particular, we use a stacking technique to derive the average properties of radio objects undetected in the Chandra images. The results of our analysis are collected in a new catalog containing the position of the optical/IR counterpart, the redshift information, and the X-ray fluxes. It is the deepest multi-wavelength catalog of radio sources, which will be used for future study of this galaxy population.

  4. Charging and discharging in ion implanted dielectric films used for capacitive radio frequency microelectromechanical systems switch

    SciTech Connect (OSTI)

    Li Gang; Chen Xuyuan [Pen-Tung Sah Micro-Electro-Mechanical Systems Research Center, Xiamen University, Xiamen, Fujian 361005 (China); Faculty of Science and Engineering, Vestfold University College, P.O. Box 2243, N-3103 Toensberg (Norway); San Haisheng [Pen-Tung Sah Micro-Electro-Mechanical Systems Research Center, Xiamen University, Xiamen, Fujian 361005 (China)

    2009-06-15T23:59:59.000Z

    In this work, metal-insulator-semiconductor (MIS) capacitor structure was used to investigate the dielectric charging and discharging in the capacitive radio frequency microelectromechanical switches. The insulator in MIS structure is silicon nitride films (SiN), which were deposited by either low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) processes. Phosphorus or boron ions were implanted into dielectric layer in order to introduce impurity energy levels into the band gap of SiN. The relaxation processes of the injected charges in SiN were changed due to the ion implantation, which led to the change in relaxation time of the trapped charges. In our experiments, the space charges were introduced by stressing the sample electrically with dc biasing. The effects of implantation process on charge accumulation and dissipation in the dielectric are studied by capacitance-voltage (C-V) measurement qualitatively and quantitatively. The experimental results show that the charging and discharging behavior of the ion implanted silicon nitride films deposited by LPCVD is quite different from the one deposited by PECVD. The charge accumulation in the dielectric film can be reduced by ion implantation with proper dielectric deposition method.

  5. A close-coupling multi-antenna type radio frequency driven ion source

    SciTech Connect (OSTI)

    Oka, Y. [National Institute for Fusion Science, Oroshi, Toki, 509-5292 Gifu (Japan); Shoji, T. [Nagoya University, Chikusa, Nagoya 464-8603 (Japan)

    2012-02-15T23:59:59.000Z

    A newly close coupling multi-antenna type radio frequency driven ion source is tested for the purpose of essentially improving plasma coupling on the basis of our old type ion source, which reuses a NNBI (negative ion source for neutral beam injection) ion source used in 1/5th scale of the Large Helical Device NNBI. The ion source and the antenna structure are described, and the efficient plasma production in terms of the positive ion saturation current (the current density) is studied. The source is made of a metal-walled plasma chamber which is desirable from the point of view of the structural toughness for fusion and industrial application, etc. At around 160 kW of rf input power, the ion saturation current density successfully reaches the 5 A/cm{sup 2} level with a gas pressure of 0.6-2 Pa in hydrogen for 10 ms pulse duration. The rf power efficiency of the plasma production with a close coupling configuration of the antenna is improved substantially compared to that with the previous antenna unit in the old type ion source. The power efficiency is assessed as competing with that of other types of sources.

  6. Results from sudden loss of vacuum on scaled superconducting radio frequency cryomodule experiment

    SciTech Connect (OSTI)

    Dalesandro, Andrew A.; Theilacker, Jay C. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Dhuley, Ram C.; Van Sciver, Steven W. [National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States)

    2014-01-29T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities for particle accelerators are at risk of failure due to sudden loss of vacuum (SLV) adjacent to liquid helium (LHe) spaces. To better understand this failure mode and its associated risks an experiment is designed to test the longitudinal effects of SLV within the beam tube of a scaled SRF cryomodule that has considerable length relative to beam tube cross section. The scaled cryomodule consists of six individual SRF cavities each roughly 350 mm long, initially cooled to 2 K by a superfluid helium bath and a beam tube pumped to vacuum. A fast-acting solenoid valve is used to simulate SLV on the beam tube, from which point it takes over 3 s for the beam tube pressure to equalize with atmosphere, and 30 s for the helium space to reach the relief pressure of 4 bara. A SLV longitudinal effect in the beam tube is evident in both pressure and temperature data, but interestingly the temperatures responds more quickly to SLV than do the pressures. It takes 500 ms (roughly 100 ms per cavity) for the far end of the 2 m long beam tube to respond to a pressure increase compared to 300 ms for temperature (approximately 50 ms per cavity). The paper expands upon these and other results to better understand the longitudinal effect for SRF cryomodules due to SLV.

  7. Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities

    SciTech Connect (OSTI)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)

    2013-06-01T23:59:59.000Z

    We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2?10{sup 10} at 2K.

  8. Matching an H{sup –} beam into a radio frequency quadrupole at Rutherford Appleton Laboratory

    SciTech Connect (OSTI)

    Gabor, C., E-mail: christoph.gabor@stfc.ac.uk; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P. [STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX (United Kingdom)] [STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX (United Kingdom); Back, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)] [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2014-02-15T23:59:59.000Z

    A major component of work being carried out to upgrade the ISIS spallation neutron source at Rutherford Appleton Laboratory (RAL) is the Front End Test Stand (FETS). FETS is aimed at improving the luminosity of the linac, and consists of a Penning ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), and Medium Energy Beam Transport (MEBT). It may serve as a first part of the accelerator chain providing a 60 mA, 3 MeV H{sup –} beam up to a 10% duty cycle. The current output of the source and the transmission of the LEBT are reasonable, but there are issues with the alignment to provide a centred beam matched into the acceptance of the RFQ. Improvements have been made to the post acceleration to address this problem. Measurements with a collimated beam have been performed to understand the behaviour of the solenoids and steerer magnets. Comparing these results with simulations proved that, besides possible mechanical imperfections of the ion source and post acceleration assembly, agreement can only be achieved if the magnetic fields are distorted.

  9. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    SciTech Connect (OSTI)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01T23:59:59.000Z

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  10. Method of making radio frequency ion source antenna and such antenna

    DOE Patents [OSTI]

    Ehlers, K.W.; Leung, K.N.

    1985-05-22T23:59:59.000Z

    In the method, the radio frequency (rf) antenna is made by providing a clean coil made of copper tubing or other metal conductor, which is coated with a tacky organic binder, and then with a powdered glass frit, as by sprinkling the frit uniformly over the binder. The coil is then heated internally in an inert gas atmosphere, preferably by passing an electrical heating current along the coil. Initially, the coil is internally heated to about 200/sup 0/C to boil off the water from the binder, and then to about 750 to 850/sup 0/C to melt the glass frit, while also burning off the organic binder. The melted frit forms a molten glass coating on the metal coil, which is then cooled to solidify the glass, so that the metal coil is covered with a thin continuous homogeneous impervious glass coating of substantially uniform thickness. The glass coating affords complete electrical insulation and complete dielectric protection for the metal coil of the rf antenna, to withstand voltage breakdown and to prevent sputtering, while also doubling the plasma generating efficiency of the rf antenna, when energized with RF power in the vacuum chamber of an ion source for a particle accelerator or the like. The glass frit preferably contains approximately 45% lead oxide.

  11. Loading and Regeneration Analysis of a Diesel Particulate Filter with a Radio Frequency-Based Sensor

    SciTech Connect (OSTI)

    Sappok, Alex [Filter Sensing Technologies] [Filter Sensing Technologies; Prikhodko, Vitaly Y [ORNL] [ORNL; Parks, II, James E [ORNL

    2010-01-01T23:59:59.000Z

    Accurate knowledge of diesel particulate filter (DPF) loading is critical for robust and efficient operation of the combined engine-exhaust aftertreatment system. Furthermore, upcoming on-board diagnostics regulations require on-board technologies to evaluate the status of the DPF. This work describes the application of radio frequency (RF) based sensing techniques to accurately measure DPF soot levels and the spatial distribution of the accumulated material. A 1.9L GM turbo diesel engine and a DPF with an RF-sensor were studied. Direct comparisons between the RF measurement and conventional pressure-based methods were made. Further analysis of the particulate matter loading rates was obtained with a mass-based soot emission measurement instrument (TEOM). Comparison with pressure drop measurements show the RF technique is unaffected by exhaust flow variations and exhibits a high degree of sensitivity to DPF soot loading and good dynamic response. Additional computational and experimental work further illustrates the spatial resolution of the RF measurements. Based on the experimental results, the RF technique shows significant promise for improving DPF control enabling optimization of the combined engine-aftertreatment system for improved fuel economy and extended DPF service life.

  12. Radio-frequency sheaths physics: Experimental characterization on Tore Supra and related self-consistent modeling

    SciTech Connect (OSTI)

    Jacquot, Jonathan; Colas, Laurent, E-mail: laurent.colas@cea.fr; Corre, Yann; Goniche, Marc; Gunn, Jamie; Kubi?, Martin [CEA, IRFM, F-13108 saint-Paul-Lez-Durance (France); Milanesio, Daniele [Department of Electronics Politecnico di Torino, Torino (Italy); Heuraux, Stéphane [IJL UMR 7198, U. de Lorraine P2M, Fac. Des Sciences, BP 70239, F-54506 Vandoeuvre Cedex (France)

    2014-06-15T23:59:59.000Z

    During the 2011 experimental campaign, one of the three ion cyclotron resonance heating (ICRH) antennas in the Tore Supra tokamak was equipped with a new type of Faraday screen (FS). The new design aimed at minimizing the integrated parallel electric field over long field lines as well as increasing the heat exhaust capability of the actively cooled screen. It proved to be inefficient for attenuating the radio-frequency (RF)-sheaths on the screen itself on the contrary to the heat exhaust concept that allowed operation despite higher heat fluxes on the antenna. In parallel, a new approach has been proposed to model self-consistently RF sheaths: the SSWICH (Self-consistent Sheaths and Waves for IC Heating) code. Simulations results from SSWICH coupled with the TOPICA antenna code were able to reproduce the difference between the two FS designs and part of the spatial pattern of heat loads and Langmuir probe floating potential. The poloidal pattern is a reliable result that mainly depends on the electrical design of the antenna while the radial pattern is on the contrary highly sensitive to loosely constrained parameters such as perpendicular conductivity that generates a DC current circulation from the private region inside the antenna limiters to the free scrape off layer outside these limiters. Moreover, the cantilevered bars seem to be the element in the screen design that enhanced the plasma potential.

  13. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.

    2012-04-01T23:59:59.000Z

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  14. Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas

    SciTech Connect (OSTI)

    Tuccillo, Angelo A.; Ceccuzzi, Silvio [Unità Tecnica Fusione ENEA, C. R. Frascati, 00044 RM (Italy); Phillips, Cynthia K. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-06-15T23:59:59.000Z

    It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion “burn” may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to “demo” and “fusion power plant.” A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of power to the plasma while minimizing the interaction between the plasma and launching structures. These potentially harmful interactions between the plasma and the vessel and launching structures are challenging: (i) significant and variable loss of power in the edge regions of confined plasmas and surrounding vessel structures adversely affect the core plasma performance and lifetime of a device; (ii) the launcher design is partly “trial and error,” with the consequence that launchers may have to be reconfigured after initial tests in a given device, at an additional cost. Over the broader frequency range, another serious gap is a quantitative lack of understanding of the combined effects of nonlinear wave-plasma processes, energetic particle interactions and non-axisymmetric equilibrium effects on determining the overall efficiency of plasma equilibrium and stability profile control techniques using RF waves. This is complicated by a corresponding lack of predictive understanding of the time evolution of transport and stability processes in fusion plasmas.

  15. H{sup -} beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source

    SciTech Connect (OSTI)

    Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N. [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2012-02-15T23:59:59.000Z

    H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.

  16. Three-dimensional self-consistent simulations of multipacting in superconducting radio frequency cavities

    SciTech Connect (OSTI)

    Chet Nieter

    2010-12-01T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities are a popular choice among researchers designing new accelerators because of the reduced power losses due to surface resistance. However, SRF cavities still have unresolved problems, including the loss of power to stray electrons. Sources of these electrons are field emission from the walls and ionization of background gas, but the predominant source is secondary emission yield (SEY) from electron impact. When the electron motion is in resonance with the cavity fields the electrons strike the cavity surface repeatedly creating a resonant build up of electrons referred to as multipacting. Cavity shaping has successfully reduced multipacting for cavities used in very high energy accelerators. However, multipacting is still a concern for the cavity power couplers, where shaping is not possible, and for cavities used to accelerate particles at moderate velocities. This Phase II project built upon existing models in the VORPAL simulation framework to allow for simulations of multipacting behavior in SRF cavities and their associated structures. The technical work involved allowed existing models of secondary electron generation to work with the complex boundary conditions needed to model the cavity structures. The types of data produced by VORPAL were also expanded to include data common used by cavity designers to evaluate cavity performance. Post-processing tools were also modified to provide information directly related to the conditions that produce multipacting. These new methods were demonstrated by running simulations of a cavity design being developed by researchers at Jefferson National Laboratory to attempt to identify the multipacting that would be an issue for the cavity design being considered. These simulations demonstrate that VORPAL now has the capabilities to assist researchers working with SRF cavities to understand and identify possible multipacting issues with their cavity designs.

  17. HEATING THE HOT ATMOSPHERES OF GALAXY GROUPS AND CLUSTERS WITH CAVITIES: THE RELATIONSHIP BETWEEN JET POWER AND LOW-FREQUENCY RADIO EMISSION

    SciTech Connect (OSTI)

    O'Sullivan, E.; Raychaudhury, S.; Ponman, T. J. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Giacintucci, S.; David, L. P.; Gitti, M.; Vrtilek, J. M., E-mail: ejos@star.sr.bham.ac.uk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2011-07-01T23:59:59.000Z

    We present scaling relations between jet power and radio power measured using the Giant Metrewave Radio Telescope (GMRT), Chandra, and XMM-Newton, for a sample of nine galaxy groups combined with the BIrzan et al. sample of clusters. Cavity power is used as a proxy for mechanical jet power. Radio power is measured at 235 MHz and 1.4 GHz, and the integrated 10 MHz-10 GHz radio luminosity is estimated from the GMRT 610-235 MHz spectral index. The use of consistently analyzed, high-resolution low-frequency radio data from a single observatory makes the radio powers for the groups more reliable than those used by previous studies, and the combined sample covers 6-7 decades in radio power and 5 decades in cavity power. We find a relation of the form P{sub jet}{proportional_to} L{approx}0.7{sub radio} for integrated radio luminosity, with a total scatter of {sigma}{sub Lrad} = 0.63 and an intrinsic scatter of {sigma}{sub i,Lrad} = 0.59. A similar relation is found for 235 MHz power, but a slightly flatter relation with greater scatter is found for 1.4 GHz power, suggesting that low-frequency or broadband radio measurements are superior jet power indicators. We find our low-frequency relations to be in good agreement with previous observational results. Comparison with jet models shows reasonable agreement, which may be improved if radio sources have a significant low-energy electron population. We consider possible factors that could bias our results or render them more uncertain, and find that correcting for such factors in those groups we are able to study in detail leads to a flattening of the P{sub jet}:L{sub radio} relation.

  18. The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies

    E-Print Network [OSTI]

    Goeke, Robert F.

    The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a ...

  19. Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-Like Shale Oil

    SciTech Connect (OSTI)

    Burnham, A K

    2003-08-20T23:59:59.000Z

    A process is proposed to convert oil shale by radio frequency heating over a period of months to years to create a product similar to natural petroleum. Electrodes would be placed in drill holes, either vertical or horizontal, and a radio frequency chosen so that the penetration depth of the radio waves is of the order of tens to hundreds of meters. A combination of excess volume production and overburden compaction drives the oil and gas from the shale into the drill holes, where it is pumped to the surface. Electrical energy for the process could be provided initially by excess regional capacity, especially off-peak power, which would generate {approx}3 x 10{sup 5} bbl/day of synthetic crude oil, depending on shale grade. The electricity cost, using conservative efficiency assumptions, is $4.70 to $6.30/bbl, depending on grade and heating rate. At steady state, co-produced gas can generate more than half the electric power needed for the process, with the fraction depending on oil shale grade. This would increase production to 7.3 x 10{sup 5} bbl/day for 104 l/Mg shale and 1.6 x 10{sup 6} bbl/day for 146 l/Mg shale using a combination of off-peak power and power from co-produced gas.

  20. Calibrating High-Precision Faraday Rotation Measurements for LOFAR and the Next Generation of Low-Frequency Radio Telescopes

    E-Print Network [OSTI]

    Sotomayor-Beltran, C; Hessels, J W T; de Bruyn, G; Noutsos, A; Alexov, A; Anderson, J; Asgekar, A; Avruch, I M; Beck, R; Bell, M E; Bell, M R; Bentum, M J; Bernardi, G; Best, P; Birzan, L; Bonafede, A; Breitling, F; Broderick, J; Brouw, W N; Brueggen, M; Ciardi, B; de Gasperin, F; Dettmar, R -J; van Duin, A; Duscha, S; Eisloeffel, J; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Griessmeier, J; Grit, T; Gunst, A W; Hassall, T E; Heald, G; Hoeft, M; Horneffer, A; Iacobelli, M; Juette, E; Karastergiou, A; Keane, E; Kohler, J; Kramer, M; Kondratiev, V I; Koopmans, L V E; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Maat, P; Macario, G; Markoff, S; McKean, J P; Mulcahy, D D; Munk, H; Orru, E; Paas, H; Pandey-Pommier, M; Pilia, M; Pizzo, R; Polatidis, A G; Reich, W; Roettgering, H; Serylak, M; Sluman, J; Stappers, B W; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Vermeulen, R; van Weeren, R J; Wijers, R A M J; Wijnholds, S J; Wise, M W; Wucknitz, O; Yatawatta, S; Zarka, P; 10.1051/0004-6361/201220728

    2013-01-01T23:59:59.000Z

    Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation contribution. We present ionFR, a code that calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. ionFR uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. We describe applications of this code for the calibration of radio polarimetric observations, and demonstrate the high accuracy of its modeled ionospheric Faraday rotations using LOFAR pulsar observations. These show that we can accurately determine some of the highest-precision pulsar rotation measures ever achieved. Precision rotation measures can be used to monitor rotation measure variations - e...

  1. VERY LONG BASELINE ARRAY MULTI-FREQUENCY POLARIMETRIC IMAGING OF RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    SciTech Connect (OSTI)

    Hayashi, Takayuki J.; Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Doi, Akihiro, E-mail: t.hayashi@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa, 252-5210 (Japan)

    2013-07-20T23:59:59.000Z

    We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using the Very Long Baseline Array at milliarcsecond resolutions to investigate the inclination of the nonthermal jet and test the hypothesis that radio sources in BAL quasars are still young. Among these four sources, J0928+446, J1018+0530, and J1405+4056 show one-sided structures in parsec scales and polarized emission detected in the core. These characteristics are consistent with those of blazars. We set constraints on viewing angles to <66 Degree-Sign for these jets in the framework of a Doppler beaming effect. J1159+0112 exhibits an unpolarized gigahertz-peaked spectrum component and several discrete blobs with steep spectra on both sides of the central component across {approx}1 kpc. These properties are consistent with those of young radio sources. We discuss the structures of jets and active galactic nucleus wind.

  2. LOW-FREQUENCY RADIO-FIR CORRELATION IN NORMAL GALAXIES AT {approx}1 kpc SCALES

    SciTech Connect (OSTI)

    Basu, Aritra; Roy, Subhashis; Mitra, Dipanjan, E-mail: aritra@ncra.tifr.res.in, E-mail: roy@ncra.tifr.res.in, E-mail: dmitra@ncra.tifr.res.in [National Center for Radio Astrophysics, TIFR, Pune University Campus, Ganeshkhind Road, Pune-411007 (India)

    2012-09-10T23:59:59.000Z

    We study the radio-FIR correlation between the nonthermal (synchrotron) radio continuum emission at {lambda}90 cm (333 MHz) and the far-infrared emission due to cool ({approx}20 K) dust at {lambda}70 {mu}m in spatially resolved normal galaxies at scales of {approx}1 kpc. The slope of the radio-FIR correlation significantly differs between the arm and interarm regions. However, this change is not evident at a lower wavelength of {lambda}20 cm (1.4 GHz). We find the slope of the correlation in the arm to be 0.8 {+-} 0.12 and we use this to determine the coupling between equipartition magnetic field (B{sub eq}) and gas density ({rho}{sub gas}) as B{sub eq}{proportional_to}{rho}{sup 0.51{+-}0.12}{sub gas}. This is close to what is predicted by magnetohydrodynamic simulations of turbulent interstellar medium, provided the same region produces both the radio and far-infrared emission. We argue that at 1 kpc scales this condition is satisfied for radio emission at 1.4 GHz and may not be satisfied at 333 MHz. The change of slope observed in the interarm region could be caused by propagation of low energy ({approx}1.5 GeV) and long-lived ({approx}10{sup 8} yr) cosmic-ray electrons at 333 MHz.

  3. assessing radio-isotope identification: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    will be provided by a combination of Cherenkov counters: a ring-imaging detector Physics Requirement 27 Collaboration Identification Physics Websites Summary: S , ,...

  4. Laser measurement of H{sup -} ions in a field-effect-transistor based radio frequency ion source

    SciTech Connect (OSTI)

    Tanaka, N.; Matsuno, T.; Funaoi, T.; Ando, A. [Tohoku University, Aramaki 6-6-05, Aoba, Sendai, Miyagi 980-8579 (Japan); Tauchi, Y. [Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi 755-8611 (Japan); Nakano, H.; Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Oroshi-Cho 322-6, Toki, Gifu 509-5292 (Japan)

    2012-02-15T23:59:59.000Z

    Hydrogen negative ion density measurements are required to clarify the characteristics of negative ion production and ion source performance. Both of laser photodetachment and cavity ring down (CRD) measurements have been implemented to a field-effect-transistor based radio-frequency ion source. The density ratio of negative hydrogen ions to electrons was successfully measured by laser photodetachment and effect of magnetic filter field on negative ion density was confirmed. The calculated CRD signal showed that CRD mirrors with >99.990% reflectivity are required and loss of reflectivity due to cesium contamination should be minimized.

  5. Physical properties of the gamma-ray binary LS 5039 through low and high frequency radio observations

    E-Print Network [OSTI]

    Marcote, B; Paredes, J M; Ishwara-Chandra, C H

    2015-01-01T23:59:59.000Z

    We have studied in detail the 0.15-15 GHz radio spectrum of the gamma-ray binary LS 5039 to look for a possible turnover and absorption mechanisms at low frequencies, and to constrain the physical properties of its emission. We have analysed two archival VLA monitorings, all the available archival GMRT data and a coordinated quasi-simultaneous observational campaign conducted in 2013 with GMRT and WSRT. The data show that the radio emission of LS 5039 is persistent on day, week and year timescales, with a variability $\\lesssim 25~\\%$ at all frequencies, and no signature of orbital modulation. The obtained spectra reveal a power-law shape with a curvature below 5 GHz and a turnover at $\\sim0.5$ GHz, which can be reproduced by a one-zone model with synchrotron self-absorption plus Razin effect. We obtain a coherent picture for a size of the emitting region of $\\sim0.85~\\mathrm{mas}$, setting a magnetic field of $B\\sim20~\\mathrm{mG}$, an electron density of $n_{\\rm e}\\sim4\\times10^5~{\\rm cm^{-3}}$ and a mass-los...

  6. Radio-frequency identification could help reduce the spread of plant pathogens

    E-Print Network [OSTI]

    Luvisi, Andrea; Panattoni, Alessandra; Triolo, Enrico

    2012-01-01T23:59:59.000Z

    identifying and verifying agrochemicals in food traceabilitytreatment specifics (agrochemicals and dates of treatment),ing and application of agrochemicals and Database links

  7. Mitigating container security risk using real-time monitoring with active Radio Frequency Identification and sensors

    E-Print Network [OSTI]

    Schlesinger, Adam Ian

    2005-01-01T23:59:59.000Z

    The global village in which we live enables increased trade and commerce across regions but also brings a complicated new set of challenges such as terrorist activity, human and drug smuggling and theft in foreign or ...

  8. Radio-frequency identification could help reduce the spread of plant pathogens

    E-Print Network [OSTI]

    Luvisi, Andrea; Panattoni, Alessandra; Triolo, Enrico

    2012-01-01T23:59:59.000Z

    Agricultural Information Management Standards (AIMS) system provides a platform to dis- seminate standards and good practices

  9. Analyzing the use of radio frequency identification (RFID) on the container industry

    E-Print Network [OSTI]

    Panagopoulos, Nikolaos-Stavros

    2007-01-01T23:59:59.000Z

    After the terrorist attacks of 9/11 US realized the importance of building and maintaining a secure environment that would protect US borders. The significance of having a secure supply chain in the US is apparent, since ...

  10. ARG-US RADIO FREQUENCY IDENTIFICATION (RFID) Technology (IN-08-046) -

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032)8Li (59AJ76) (See theDoctoral20ALSNewstt^APPLIANCE STANDARDS

  11. Modeling and identification of continuous-time system for RF amplifiers

    E-Print Network [OSTI]

    Boyer, Edmond

    Modeling and identification of continuous-time system for RF amplifiers Mourad Djamai 1 , Smail present a new identification proce- dure for radio frequency Power Amplifier (PA) in the presence signals in time domain. I. INTRODUCTION Numerous approaches in Power Amplifier identification area have

  12. New Architectures for Radio-Frequency DC-DC Power Conversion

    E-Print Network [OSTI]

    Rivas, Juan M.

    This document proposes two new architectures for switched-mode dc–dc power conversion. The proposed architectures enable dramatic increases in switching frequency to be realized while preserving features critical in practice, ...

  13. Lossless multi-way power combining and outphasing for radio frequency power amplifiers

    E-Print Network [OSTI]

    Jurkov, Alexander S

    2013-01-01T23:59:59.000Z

    For applications requiring the use of power amplifiers (PAs) operating at high frequencies and power levels, it is often preferable to construct multiple low power PAs and combine their output powers to form a high-power ...

  14. Growth optimization and structural analysis for ferromagnetic Mn-doped ZnO layers deposited by radio frequency magnetron sputtering

    SciTech Connect (OSTI)

    Abouzaid, M.; Ruterana, P.; Liu, C.; Morkoc, H. [SIFCOM UMR 6176 CNRS-ENSICAEN, 6 Boulevard du Marechal Juin, 14050 Caen Cedex (France); Department of Electrical Engineering, Virginia Commonwealth University, Richmond Virginia 23284 (United States)

    2006-06-01T23:59:59.000Z

    The effect of the deposition temperature on the crystalline quality of (Zn,Mn)O is investigated in thin films prepared by radio frequency magnetron sputtering on c-plane sapphire and GaN substrates. The layers are made of a 0.5 {mu}m Mn-doped layer towards the surface on top of a 150 nm pure ZnO buffer. Depending on the deposition temperature, the layers can exhibit a columnar structure; the adjacent domains are rotated from one another by 90 deg. , putting [1010] and [1120] directions face to face. At high Mn concentration the columnar structure is blurred by the formation of Mn rich precipitates. Only one variety of domains is observed at an optimal deposition temperature of 500 deg. C: they are slightly rotated around the [0001] axis (mosaic growth) and bounded by threading dislocations.

  15. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun

    SciTech Connect (OSTI)

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-08-15T23:59:59.000Z

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5?MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  16. Reduced leakage in epitaxial BiFeO{sub 3} films following oxygen radio frequency plasma treatment

    SciTech Connect (OSTI)

    Kothari, Deepti [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India) [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Upadhyay, Sanjay K.; Raghavendra Reddy, V. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India)] [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Jariwala, C.; Raole, P. M. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2013-06-07T23:59:59.000Z

    Epitaxial BiFeO{sub 3} (BFO) films were deposited using pulsed laser deposition method. The prepared films were characterized using x-ray diffraction, x-ray reflectivity, ferroelectric loop tracer, and leakage current measurements before and after oxygen plasma treatment. The leakage current of the films, a crucial parameter in device applications, is observed to be reduced by two orders of magnitude with oxygen plasma treatment at room temperature. P-E hysteresis loops were observed in oxygen plasma treated BFO films. The observed results indicate the usefulness of oxygen radio frequency plasma treatment (RF 13.56 MHz), which is an effective and low temperature processing technique, in such lossy ferroelectric thin films.

  17. Extracted ion current density in close-coupling multi-antenna type radio frequency driven ion source: CC-MATIS

    SciTech Connect (OSTI)

    Oka, Y., E-mail: oka@sc.starcat.ne.jp, E-mail: oka@LHD.nifs.ac.jp [National Institute for Fusion Science, Oroshi, Toki 509-5292 (Japan); Shoji, T. [Nagoya University, Chikusa, Nagoya 464-8603 (Japan)] [Nagoya University, Chikusa, Nagoya 464-8603 (Japan)

    2014-02-15T23:59:59.000Z

    Positive ions are extracted by using a small extractor from the Close-Coupling Multi-Antenna Type radio frequency driven Ion Source. Two types of RF antenna are used. The maximum extracted ion current density reaches 0.106 A/cm{sup 2}. The RF net power efficiency of the extracted ion current density under standard condition is 11.6 mA/cm{sup 2}/kW. The efficiency corresponds to the level of previous beam experiments on elementary designs of multi-antenna sources, and also to the efficiency level of a plasma driven by a filament in the same chamber. The multi-antenna type RF plasma source is promising for all metal high density ion sources in a large volume chamber.

  18. Experimental measurements in a radio frequency discharge heated supersonic flow: Evaluation of a potential electric propulsion thruster

    SciTech Connect (OSTI)

    Wantuck, P.J.; Hull, D.E.

    1991-01-01T23:59:59.000Z

    An operational radio frequency discharge-driven supersonic flow system, which utilizes an inductively and capacitively coupled plasma (ICCP) tube to produce high enthalpy source gas, is described. The ICCP coupled to a properly designed nozzle represents a potential electric propulsion device. The high gas temperatures achieved in the plasma discharge (> 5000 K) and the electrodeless nature of the tube's operation offers potentially high thruster performance coupled and long operational lifetime. A preliminary characterization of the current system was established using emission and probe-based measurements. A nominal peak specific impulse of 155 s was estimated for operation with argon. The calculated thrust based upon the peak velocity and mass flow through the device is 1.1 N. 14 refs., 10 figs.

  19. Implementation of a Dual Containment/Surveillance System utilizing scene-change detection and radio frequency technology

    SciTech Connect (OSTI)

    FITZGERALD, ERIC; KOENIG, RICHARD

    2005-06-27T23:59:59.000Z

    This paper will examine the implementation of scene-change detection and radio frequency technology within a Dual Containment/Surveillance (C/S) System. Additionally, this paper will examine the human performance factors in the operation of these systems. Currently, Westinghouse Savannah River Company utilizes the Continuous Item Monitoring and Surveillance System (CIMS) in the performance of Dual C/S to monitor special nuclear materials within International Atomic Energy Agency (IAEA) Safeguards and Domestic Safeguards. CIMS is comprised of the Material Monitoring System (MMS) (R), a multi-media electronic surveillance system developed by Sandia National Laboratory which incorporates the use of active seals commonly called Radio Frequency Tamper Indicating Devices (RFTIDs), NT Vision (R) as developed by Los Alamos National Laboratory, a Microsoft Windows NT (R) based operating system providing for domestic scene-change detection and the Digital Multi-Camera Optical Surveillance System (DMOS) (R) which provides scene-change detection for IAEA. Although this paper will focus on the implementation of Dual C/S utilizing the Continuous Item Monitoring and Surveillance System, the necessity for a thorough review of Safeguards and Security requirements with organizations and personnel having minimal to no prior MPC&A training will also be covered. Successful Dual C/S implementation plans must consider not only system design and failure modes, but must also be accompanied with the appropriate ''mind shift'' within operations and technical personnel. This is required to ensure completion of both physical and electronic activities, and system design changes are performed conscientiously and with full awareness of MPC&A requirements.

  20. Radio frequency accelerating cavity having slotted irises for damping certain electromagnetic modes

    DOE Patents [OSTI]

    Palmer, R.B.

    1991-05-21T23:59:59.000Z

    An accelerating cavity is disclosed having one or more iris structures mounted therein for strongly damping unwanted frequencies that are generated in the cavity by bunches of particles in a particle beam that is accelerated through the cavity during its operation. Each of the iris structures is characterized by containing a plurality of radial slots therein that extend from the central aperture through the iris member to the perimeter thereof. The outer end of each of the radial slots includes an enlarged portion that is effective to prevent undesired frequencies from being reflected back into the center aperture of the iris member. Waveguide means connect the outer ends of the radial slots to frequency damping means or to a dump or dumps. 17 figures.

  1. Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference

    DOE Patents [OSTI]

    Simpson, James E. (Gaithersburg, MD)

    1999-01-01T23:59:59.000Z

    An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp.

  2. Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference

    DOE Patents [OSTI]

    Simpson, J.E.

    1999-06-08T23:59:59.000Z

    An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp. 18 figs.

  3. Noise Macromodel for Radio Frequency Integrated Circuits Noise performance is a critical analog and RF

    E-Print Network [OSTI]

    Li, Xin

    translation. Moreover, low Noise Amplifiers (LNA) are usually treated as LTI systems, but when the design process. In this paper we propose a noise macromodel for analog circuits and demonstrate it by way designers for back-of-the-envelope calculations, it only specifies noise performance at a given frequency

  4. Radio frequency (RF) microwave components and subsystems using loaded ridge waveguide

    DOE Patents [OSTI]

    Kang, Yoon W.

    2013-08-20T23:59:59.000Z

    A waveguide having a non-conductive material with a high permeability (.mu., .mu..sub.r for relative permeability) and/or a high permittivity (.di-elect cons., .di-elect cons..sub.r for relative permittivity) positioned within a housing. When compared to a hollow waveguide, the waveguide of this invention, reduces waveguide dimensions by .varies..mu. ##EQU00001## The waveguide of this invention further includes ridges which further reduce the size and increases the usable frequency bandwidth.

  5. Implementation guidance for industrial-level security systems using radio frequency alarm links

    SciTech Connect (OSTI)

    Swank, R.G.

    1996-07-12T23:59:59.000Z

    Spread spectrum (SS) RF transmission technologies have properties that make the transmitted signal difficult to intercept, interpret, and jam. The digital code used in the modulation process results in a signal that has high reception reliability and supports multiple use of frequency bands and selective addressing. These attributes and the relatively low installation cost of RF systems make SSRF technologies candidate for communications links in security systems used for industrial sites, remote locations, and where trenching or other disturbances of soil or structures may not be desirable or may be costly. This guide provides a description of such a system and presents implementation methods that may be of engineering benefit.

  6. Investigation of inherent radio frequency oscillation and minor switching in amorphous chalcogenide semiconductors

    E-Print Network [OSTI]

    Gill, Robert Wayne

    1971-01-01T23:59:59.000Z

    of mismatch. The selection of a detector was the next problem which had to be solved. The first unit tried was a Hewlett Packard 310A harmonic wave analyzer. Figure 7 shows the block diagram for using 18 12 10 1 2 3 4 5 6 7 8 TIME (HOURS) Figure 6.../division. Circuit configuration used for direct counting of r-f oscillation. 14 Circuit configuration and voltage waveforms used for eliminating system transients. 16 Frequency drift of the Hewlett Packard 608F signal generator with a stabilization period of 48...

  7. Field limit and nano-scale surface topography of superconducting radio-frequency cavity made of extreme type II superconductor

    E-Print Network [OSTI]

    Kubo, Takayuki

    2014-01-01T23:59:59.000Z

    The field limit of superconducting radio-frequency cavity made of type II superconductor with a large Ginzburg-Landau parameter is studied with taking effects of nano-scale surface topography into account. If the surface is ideally flat, the field limit is imposed by the superheating field. On the surface of cavity, however, nano-defects almost continuously distribute and suppress the superheating field everywhere. The field limit is imposed by an effective superheating field given by the product of the superheating field for ideal flat surface and a suppression factor that contains effects of nano-defects. A nano-defect is modeled by a triangular groove with a depth smaller than the penetration depth. An analytical formula for the suppression factor of bulk and multilayer superconductors are derived in the framework of the London theory. As an immediate application, the suppression factor of the dirty Nb processed by the electropolishing is evaluated by using results of surface topographic study. The estimat...

  8. Assessment of Radio-Frequency Radiation Exposure Level from Selected Mobile Base Stations (MBS) in Lokoja, Kogi State, Nigeria

    E-Print Network [OSTI]

    Victor, U J Nwankwo; Dada, S S; Onugba, A A; Ushie, P

    2012-01-01T23:59:59.000Z

    The acquisition and use of mobile phone is tremendously increasing especially in developing countries, but not without a concern. The greater concern among the public is principally over the proximity of mobile base stations (MBS) to residential areas rather than the use of handsets. In this paper, we present an assessment of Radio-Frequency (RF) radiation exposure level measurements and analysis of radiation power density (in \\mu W/sq m) from mobile base stations relative to radial distance (in metre). The minimum average power density from individual base station in the town was about 47\\mu W/sq m while the average maximum was about 1.5mW/sq m. Our result showed that average power density of a base station decreases with increase in distance (from base station) and that radiation intensity varies from one base station to another even at the same distance away. Our result (obtained signature of power density variation) was also compared with the 'expected' signature. It was found that radiation from external...

  9. Roughness analysis applied to niobium thin films grown on MgO(001) surfaces for superconducting radio frequency cavity applications

    SciTech Connect (OSTI)

    D. B. Beringer, W. M. Roach, C. Clavero, C. E. Reece, R. A. Lukaszew

    2013-02-01T23:59:59.000Z

    This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF) cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of ?50??MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [ Appl. Phys. Lett. 88 012511 (2006)] was proposed to overcome this limit that involves coating superconducting layers separated by insulating ones onto the inner walls of the cavities. Thus, we have undertaken a systematic effort to understand the dynamic evolution of the Nb surface under specific deposition thin film conditions onto an insulating surface in order to explore the feasibility of the proposed model. We examine and compare the morphology from two distinct Nb/MgO series, each with its own epitaxial registry, at very low growth rates and closely examine the dynamical scaling of the surface features during growth. Further, we apply analysis techniques such as power spectral density to the specific problem of thin film growth and roughness evolution to qualify the set of deposition conditions that lead to successful SRF coatings.

  10. Record Q0 value in a heat treated large-grain superconducting radio-frequency niobium cavity

    E-Print Network [OSTI]

    Dhakal, P; Myneni, G R; Gray, K E; Groll, N; Maheshwari, P; McRae, D M; Pike, R; Proslier, T; Stevie, F; Walsh, R P; Yang, Q; Zasadzinzki, J

    2012-01-01T23:59:59.000Z

    Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of "medium purity" Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800 - 1400 \\degree C was done in a newly designed vacuum induction furnace. $Q_0$ values of the order of $2\\times10^{10}$ at 2.0 K and peak surface magnetic field ($B_p$) of 90 mT were achieved reproducibly. A record $Q_0$-value of $4.67\\times10^{10}$ at 2.0 K and $B_p$ = 90 mT was obtained after heat treatment at 1400 \\degree C. Samples heat treated with the cavity at 1400 \\degree C were analyzed by secondary ion mass spectrometry, secondary electron microscopy, energy dispersive X-ray, point contact tunneling and X-ray diffraction and revealed a complex surface composition which includes titanium oxide,...

  11. Growth of amorphous TeO{sub x} (2{<=}x{<=}3) thin film by radio frequency sputtering

    SciTech Connect (OSTI)

    Dewan, Namrata; Gupta, Vinay; Sreenivas, K.; Katiyar, R. S. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Department of Physics, University of Puerto Rico, P.O. Box 23343, San Juan, Puerto Rico 00931-3343 (Puerto Rico)

    2007-04-15T23:59:59.000Z

    Thin films of Tellurium oxide TeO{sub x} over a wide range of x (2 to 3) were prepared by radio frequency diode sputtering at room temperature on corning glass and quartz substrate. The deposited films are amorphous in nature and IR spectroscopy reveals the formation of Te-O bond. X-ray photoelectron spectroscopy shows the variation in the stoichiometry of TeO{sub x} film from x=2 to 3 with an increase in oxygen percentage (25 to 100%) in processing sputtering gas composition. Raman spectroscopy depicts the formation of TeO{sub 3} trigonal pyramid besides TeO{sub 4} disphenoid in the amorphous TeO{sub x} film with increase in the value of x. The varying stoichiometry of TeO{sub x} thin film (x=2 to 3) was found to influence the optical, electrical, and elastic properties. The optical band gap of film increases from 3.8 to 4.2 eV with increasing x and is attributed to the decrease in density. The elastic constants (C{sub 11} and C{sub 44}) of the deposited films are lower than the corresponding value reported for TeO{sub 2} single crystal.

  12. Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices

    SciTech Connect (OSTI)

    Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Hensley, Walter K.; Kouzes, Richard T.; Schweppe, John E.

    2006-07-31T23:59:59.000Z

    Lanthanum halide (LaBr3:Ce) scintillators offer significantly better resolution (<3 percent at 662 kilo-electron volt [keV]) relative to sodium iodide (NaI(Tl)) and have recently become commercially available in sizes large enough for the hand-held radio-isotope identification device (RIID) market. There are drawbacks to lanthanum halide detectors, however. These include internal radioactivity that contributes to spectral counts and a low-energy response that can cause detector resolution to be lower than that of NaI(Tl) below 100 keV. To study the potential of this new material for RIIDs, we performed a series of measurements comparing a 1.5?1.5 inch LaBr?3:Ce detector with an Exploranium GR 135 RIID, which contains a 1.5-2.2 inch NaI(Tl) detector. Measurements were taken for short time frames, as typifies RIID usage. Measurements included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. Some measurements were noncontact, involving short distances or cargo shielding scenarios. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision TM). In general, the LaBr3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr3:Ce detector was usually two to three times faster. The notable exception was for 40K containing NORM where interfering internal contamination in the LaBr3:Ce detector exist. NaI(Tl) consistently outperformed LaBr3:Ce for this important isotope. LaBr3:Ce currently costs much more than NaI(Tl), though this cost-difference is expected to diminish (but not completely) with time. As is true of all detectors, LaBr3:Ce will need to be gain-stabilized for RIID applications. This could possibly be done using the internal contaminants themselves. It is the experience of the authors that peak finding software in RIIDs needs to be improved, regardless of the detector material.

  13. Technical basis for evaluating electromagnetic and radio-frequency interference in safety-related I&C systems

    SciTech Connect (OSTI)

    Ewing, P.D.; Korsah, K. [Oak Ridge National Lab., TN (United States)

    1994-04-01T23:59:59.000Z

    This report discusses the development of the technical basis for the control of upsets and malfunctions in safety-related instrumentation and control (I&C) systems caused by electromagnetic and radio-frequency interference (EMI/RFI) and power surges. The research was performed at the Oak Ridge National Laboratory (ORNL) and was sponsored by the USNRC Office of Nuclear Regulatory Research (RES). The motivation for research stems from the safety-related issues that need to be addressed with the application of advanced I&C systems to nuclear power plants. Development of the technical basis centered around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant`s electronic and electromechanical systems known to be the source(s) of EMI/RFI and power surges. First, good EMC design and installation practices need to be established to control the impact of interference sources on nearby circuits and systems. These EMC good practices include circuit layouts, terminations, filtering, grounding, bonding, shielding, and adequate physical separation. Second, an EMI/RFI test and evaluation program needs to be established to outline the tests to be performed, the associated test methods to be followed, and carefully formulated acceptance criteria based on the intended environment to ensure that the circuit or system under test meets the recommended guidelines. Third, a program needs to be developed to perform confirmatory tests and evaluate the surge withstand capability (SWC) and of I&C equipment connected to or installed in the vicinity of power circuits within the nuclear power plant. By following these three steps, the design and operability of safety-related I&C systems against EMI/RFI and power surges can be evaluated, acceptance criteria can be developed, and appropriate regulatory guidance can be provided.

  14. A frequency scanning method for the identification of harmonic instabilities in HVDC systems

    SciTech Connect (OSTI)

    Jiang, X.; Gole, A.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Electrical and Computer Engineering] [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Electrical and Computer Engineering

    1995-10-01T23:59:59.000Z

    A Frequency Scanning Method is introduced in the paper to obtain a more accurate frequency characteristic for identifying harmonic instability in HVdc systems. An example of the application is used to identify the resonance frequencies in the CIGRE benchmark model. The paper shows that the Benchmark model is not tuned to the resonance frequency that it was designed for. Using the scanning method, the resonance frequency of the benchmark model may be shifted to demonstrate a simulation of core-saturation type instability.

  15. Radio frequency phototube

    DOE Patents [OSTI]

    Margaryan, Amur (Yerevan, AM); Gynashyan, Karlen (Yerevan, AM); Hashimoto, Osamu (Sendai, JP); Majewski, Stanislaw (Morgantown, WV); Tang, Linguang (Yorktown, VA); Marikyan, Gagik (Yerevan, AM); Marikyan, legal representative, Lia (Yerevan, AM)

    2012-03-20T23:59:59.000Z

    A method and apparatus of obtaining a record of repetitive optical or other phenomena having durations in the picosecond range, comprising a circular scan electron tube to receive light pulses and convert them to electron images consisting with fast nanosecond electronic signals, a continuous wave light or other particle pulses, e.g. electron picosecond pulses, and a synchronizing mechanism arranged to synchronize the deflection of the electron image (images) in the tube (tubes) with the repetition rate of the incident pulse train. There is also provided a method and apparatus for digitization of a repetitive and random optical waveform with a bandwidth higher than 10 GHz.

  16. A CMOS Fractional Frequency Synthesizer for a Fully Integrated S-Band Extravehicular Activity (EVA) Radio Transceiver

    E-Print Network [OSTI]

    Foli, Eugene B

    2014-04-28T23:59:59.000Z

    Extravehicular activity (EVA) is an important aspect of space explorations. It enables astronauts carry out tasks outside the protective environment of the spacecraft cabin. The crew requires EVA radio transceivers to transmit and receive...

  17. Radio-loud Narrow-Line Type 1 Quasars

    E-Print Network [OSTI]

    S. Komossa; W. Voges; D. Xu; S. Mathur; H. -M. Adorf; G. Lemson; W. Duschl; D. Grupe

    2006-03-24T23:59:59.000Z

    We present the first systematic study of (non-radio-selected) radio-loud narrow-line Seyfert 1 (NLS1) galaxies. Cross-correlation of the `Catalogue of Quasars and Active Nuclei' with several radio and optical catalogues led to the identification of 11 radio-loud NLS1 candidates including 4 previously known ones. Most of the radio-loud NLS1s are compact, steep spectrum sources accreting close to, or above, the Eddington limit. The radio-loud NLS1s of our sample are remarkable in that they occupy a previously rarely populated regime in NLS1 multi-wavelength parameter space. While their [OIII]/H_beta and FeII/H_beta intensity ratios almost cover the whole range observed in NLS1 galaxies, their radio properties extend the range of radio-loud objects to those with small widths of the broad Balmer lines. Among the radio-detected NLS1 galaxies, the radio index R distributes quite smoothly up to the critical value of R ~ 10 and covers about 4 orders of magnitude in total. Statistics show that ~7% of the NLS1 galaxies are formally radio-loud while only 2.5% exceed a radio index R > 100. Several mechanisms are considered as explanations for the radio loudness of the NLS1 galaxies and for the lower frequency of radio-louds among NLS1s than quasars. While properties of most sources (with 2-3 exceptions) generally do not favor relativistic beaming, the combination of accretion mode and spin may explain the observations. (abbreviated)

  18. Measurement and Analysis of Radio-frequency Radiation Exposure Level from Different Mobile Base Transceiver Stations in Ajaokuta and Environs, Nigeria

    E-Print Network [OSTI]

    Ushie, P O; Bolaji, Ayinmode; Osahun, O D

    2013-01-01T23:59:59.000Z

    We present the result of a preliminary assessment of radio-frequency radiation exposure from selected mobile base stations in Ajaokuta environs. The Power density of RF radiation within a radial distance of 125m was measured. Although values fluctuated due to the influence of other factors, including wave interference from other electromagnetic sources around reference base stations, we show from analysis that radiation exposure level is below the standard limit (4.5W/sqm for 900MHz and 9W/sqm for 18000MHz) set by the International Commission on Non-ionizing Radiation Protection (ICNIRP) and other regulatory agencies.

  19. LOWFREQUENCY RADIO OBSERVATIONS OF XRAY GHOST BUBBLES A2597: A HISTORY RADIO ACTIVITY THE CORE

    E-Print Network [OSTI]

    Sarazin, Craig

    LOW­FREQUENCY RADIO OBSERVATIONS OF X­RAY GHOST BUBBLES A2597: A HISTORY RADIO ACTIVITY THE CORE T showed ``ghost holes'' X­ray emission west northeast central radio galaxy PKS 2322#123. Previous radio observations detect radio emission coming from interior X­ray holes. present low­frequency observations A2597

  20. 2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency biased silicon wafer

    E-Print Network [OSTI]

    California at Los Angles, University of

    . Defining xrf ¼ 2p=srf and xion ¼ 2p=sion, the ratio of these two frequencies, xrf =xion, is an important parameter controlling ion dynamics in the sheath. For low frequency biases (xrf =xion ( 1), the transit of the bimodal distribution, DEi, decreases. At high fre- quencies (xrf =xion ) 1) DEi ! 0 and the IED converges

  1. Abstract--Radio-frequency identification has a great number of unfulfilled prospects. Part of the problem until now has been

    E-Print Network [OSTI]

    California at Los Angeles, University of

    , The University of Hong Kong; PR China. (email: gqhuang@hku.hk). Rajit Gadh is the Director of the Wireless

  2. Development of a radio frequency ion source with multi-helicon plasma injectors for neutral beam injection system of Versatile Experiment Spherical Torus

    SciTech Connect (OSTI)

    Choe, Kyumin; Jung, Bongki [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    Despite of high plasma density, helicon plasma has not yet been applied to a large area ion source such as a driver for neutral beam injection (NBI) system due to intrinsically poor plasma uniformity in the discharge region. In this study, a radio-frequency (RF) ion source with multi-helicon plasma injectors for high plasma density with good uniformity has been designed and constructed for the NBI system of Versatile Experiment Spherical Torus at Seoul National University. The ion source consists of a rectangular plasma expansion chamber (120 × 120 × 120 mm{sup 3}), four helicon plasma injectors with annular permanent magnets and RF power system. Main feature of the source is downstream plasma confinement in the cusp magnetic field configuration which is generated by arranging polarities of permanent magnets in the helicon plasma injectors. In this paper, detailed design of the multi-helicon plasma injector and plasma characteristics of the ion source are presented.

  3. Design, Construction and Operation of a Low-Power, Autonomous Radio-Frequency Data-Acquisition Station for the TARA Experiment

    E-Print Network [OSTI]

    Kunwar, S; Allen, C; Belz, J; Besson, D; Byrne, M; Farhang-Boroujeny, B; Gillman, W H; Hanlon, W; Hanson, J; Myers, I; Novikov, A; Prohira, S; Ratzlaff, K; Rezazadeh, A; Sanivarapu, V; Schurig, D; Shustov, A; Smirnova, M; Takai, H; Thomson, G B; Young, R

    2015-01-01T23:59:59.000Z

    Employing a 40-kW radio-frequency transmitter just west of Delta, UT, and operating at 54.1 MHz, the TARA (Telescope Array RAdar) experiment seeks radar detection of extensive air showers (EAS) initiated by ultra-high energy cosmic rays (UHECR). For UHECR with energies in excess of $10^{19}$ eV, the Doppler-shifted "chirps" resulting from EAS shower core radar reflections should be observable above background (dominantly galactic) at distances of tens of km from the TARA transmitter. In order to stereoscopically reconstruct cosmic ray chirps, two remote, autonomous self-powered receiver stations have been deployed. Each remote station (RS) combines both low power consumption as well as low cost. Triggering logic, the powering and communication systems, and some specific details of hardware components are discussed.

  4. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    SciTech Connect (OSTI)

    Niemi, K.; O'Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2013-07-15T23:59:59.000Z

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  5. Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

    SciTech Connect (OSTI)

    Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy); Schiesko, L. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-11-15T23:59:59.000Z

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors’ holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

  6. Impact of contact and access resistances in graphene field-effect transistors on quartz substrates for radio frequency applications

    SciTech Connect (OSTI)

    Ramón, Michael E., E-mail: michael.ramon@utexas.edu, E-mail: hemacp@utexas.edu; Movva, Hema C. P., E-mail: michael.ramon@utexas.edu, E-mail: hemacp@utexas.edu; Fahad Chowdhury, Sk.; Parrish, Kristen N.; Rai, Amritesh; Akinwande, Deji; Banerjee, Sanjay K. [Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758 (United States); Magnuson, Carl W.; Ruoff, Rodney S. [Department of Mechanical Engineering and the Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-02-17T23:59:59.000Z

    High-frequency performance of graphene field-effect transistors (GFETs) has been limited largely by parasitic resistances, including contact resistance (R{sub C}) and access resistance (R{sub A}). Measurement of short-channel (500?nm) GFETs with short (200?nm) spin-on-doped source/drain access regions reveals negligible change in transit frequency (f{sub T}) after doping, as compared to ?23% f{sub T} improvement for similarly sized undoped GFETs measured at low temperature, underscoring the impact of R{sub C} on high-frequency performance. DC measurements of undoped/doped short and long-channel GFETs highlight the increasing impact of R{sub A} for larger GFETs. Additionally, parasitic capacitances were minimized by device fabrication using graphene transferred onto low-capacitance quartz substrates.

  7. An oscillator circuit to produce a radio-frequency discharge and application to metastable helium saturated absorption spectroscopy

    SciTech Connect (OSTI)

    Moron, F.; Hoendervanger, A. L.; Bonneau, M.; Bouton, Q.; Aspect, A.; Boiron, D.; Clement, D.; Westbrook, C. I. [Laboratoire Charles Fabry, Institut d'Optique, CNRS, Univ Paris Sud, 2 Avenue Augustin Fresnel, 91127 Palaiseau Cedex (France)

    2012-04-15T23:59:59.000Z

    We present a rf gas discharge apparatus which provides an atomic frequency reference for laser manipulation of metastable helium. We discuss the biasing and operation of a Colpitts oscillator in which the discharge coil is part of the oscillator circuit. Radiofrequency radiation is reduced by placing the entire oscillator in a metal enclosure.

  8. An oscillator circuit to produce a radio-frequency discharge and application to metastable helium saturated absorption spectroscopy

    E-Print Network [OSTI]

    Moron, F; Bonneau, M; Bouton, Q; Aspect, A; Boiron, D; Clément, D; Westbrook, C I

    2012-01-01T23:59:59.000Z

    We present an rf gas discharge apparatus which provides an atomic frequency reference for laser manipulation of metastable helium. We discuss the biasing and operation of a Colpitts oscillator in which the discharge coil is part of the oscillator circuit. Radiofrequency radiation is reduced by placing the entire oscillator in a metal enclosure.

  9. Effect of high temperature heat treatments on the quality factor of a large-grain superconducting radio-frequency niobium cavity

    SciTech Connect (OSTI)

    Dhakal, P; Myneni, G R; Gray, K E; Groll, N; Maheshwari, P; McRae, D M; Pike, R; Proslier, T; Stevie, F; Walsh, R P; Yang, Q

    2013-04-01T23:59:59.000Z

    Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of “medium purity” Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800–1400°C was done in a newly designed vacuum induction furnace. Q{sub 0} values of the order of 2×10{sup 10} at 2.0 K and peak surface magnetic field (B{sub p}) of 90 mT were achieved reproducibly. A Q{sub 0} value of (5±1)×10{sup 10} at 2.0 K and B{sub p}=90??mT was obtained after heat treatment at 1400°C. This is the highest value ever reported at this temperature, frequency, and field. Samples heat treated with the cavity at 1400°C were analyzed by secondary ion mass spectrometry, x-ray photoelectron spectroscopy, energy dispersive x ray, point-contact tunneling, and x-ray diffraction, and revealed a complex surface composition which includes titanium oxide, increased carbon, and nitrogen content but reduced hydrogen concentration compared to a non-heat-treated sample.

  10. Captive Radio

    E-Print Network [OSTI]

    Rosenfeld, Lauren

    2012-01-01T23:59:59.000Z

    Captive Radio (working title) – Fine Cut Transcript,TRT: 23:20 Jungle aerials RADIO VOICE, It is 5:21 in theas the day breaks on Caracol Radio’s program, The Voices of

  11. Direct-current effects on magnetization reversal properties of submicron-size permalloy patterns for radio-frequency devices.

    SciTech Connect (OSTI)

    Zhang, H.; Hoffmann, A.; Divan, R.; Wang, P.; Clemson Univ.

    2009-01-01T23:59:59.000Z

    Ferromagnetic resonance (FMR) spectroscopy is used to measure direct-current (dc) effects on the magnetization reversal properties of submicron-sized lateral patterned magnetic material. The observed FMR frequency-field relationship shows that for both 240 and 550 nm wide Permalloy (Py) nanowires the coercivity is reduced by {approx}33% when a 50 mA dc passes through the transmission line where the nanowires are incorporated. The temperature dependence of the coercivity has a {radical}T relationship which suggests the coherent rotation mode tendency in such 100 nm thick Py nanowires.

  12. Size dependence of magnetization switching and its dispersion of Co/Pt nanodots under the assistance of radio frequency fields

    SciTech Connect (OSTI)

    Furuta, Masaki, E-mail: furutam@mail.tagen.tohoku.ac.jp; Okamoto, Satoshi; Kikuchi, Nobuaki; Kitakami, Osamu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Shimatsu, Takehito [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578 (Japan); Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan)

    2014-04-07T23:59:59.000Z

    We have studied the dot size dependence of microwave assisted magnetization switching (MAS) on perpendicular magnetic Co/Pt multilayer dot array. The significant microwave assistance effect has been observed over the entire dot size D ranging from 50?nm to 330?nm examined in the present study. The MAS behavior, however, critically depends on D. The excitation frequency dependence of the switching field is well consistent with the spin wave theory, indicating that the magnetization precession in MAS is in accordance with the well defined eigenmodes depending on the dot diameter. The lowest order spin wave is only excited for D???100?nm, and then the MAS effect is well consistent with that of the single macrospin prediction. On the other hand, higher order spin waves are excited for D?>?100?nm, giving rise to the significant enhancement of the MAS effect. The dispersion of MAS effect also depends on D and is significantly reduced for the region of D?>?100?nm. This significant reduction of the dispersion is attributed to the essential feature of the MAS effect which is insensitive to the local fluctuation of anisotropy field, such as defect, damaged layer, and so on.

  13. Effects of radio-frequency driving power, gas pressure, and nitrogen seeding on the transition dynamics in argon inductively coupled plasmas

    SciTech Connect (OSTI)

    Razzak, M. Abdur; Takamura, Shuichi; Uesugi, Yoshihiko [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Department of Electrical and Electronic Engineering, Kanazawa University 2-40-20 Kodatsuno, Ishikawa 920-8667 (Japan)

    2004-11-01T23:59:59.000Z

    The influences of rf driving power, neutral gas pressure, and nitrogen seeding on the electrostatic-to-electromagnetic (E-H) mode transition dynamics in radio-frequency argon inductively coupled plasmas (ICPs) in a pressure range of 50-100 kPa are investigated, both experimentally and theoretically. The E-H mode transition dynamics and its characteristic transition time scale are investigated by observing the high-speed imaging (13 500 fps) as well as the temporal change of plasma loading impedance. The experimental results reveal that the E-H mode transition time is not fixed at any operating conditions rather it depends on some important parameters such as the rf driving power, neutral gas pressure, gas type. It is found that the E-H mode transition time depends on the unique parameter E{sub {theta}}/p; the so-called effective induced electric field, rather than the independent parameter: the rf power or neutral gas pressure. It is also found that longer E-H mode transition time is required to ignite the high-pressure Ar-N{sub 2} plasmas with a 2.5%-10% N{sub 2} seeding than that of pure Ar plasmas with the same operating conditions. The experimental results are compared with that of the recently developed theoretical models, and a good agreement is found between them.

  14. Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering

    SciTech Connect (OSTI)

    Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K. [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)] [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

    2013-10-14T23:59:59.000Z

    We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (T{sub s}). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10{sup ?3} ? cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at T{sub s} of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein–Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ?110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

  15. Morphology and structure evolution of tin-doped indium oxide thin films deposited by radio-frequency magnetron sputtering: The role of the sputtering atmosphere

    SciTech Connect (OSTI)

    Nie, Man, E-mail: man.nie@helmholtz-berlin.de; Mete, Tayfun; Ellmer, Klaus [Department of Solar Fuels and Energy Storage Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D14109 Berlin (Germany)

    2014-04-21T23:59:59.000Z

    The microstructure and morphology evolution of tin-doped indium oxide (ITO) thin films deposited by radio-frequency magnetron sputtering in different sputtering atmospheres were investigated by X-ray diffraction, X-ray reflectivity, and atomic force microscopy. The surface roughness w increases with increasing film thickness d{sub f}, and exhibits a power law behavior w???d{sub f}{sup ?}. The roughness decreases with increasing O{sub 2} flow, while it increases with increasing H{sub 2} flow. The growth exponent ? is found to be 0.35, 0.75, and 0.98 for depositions in Ar/10%O{sub 2}, pure Ar, and Ar/10%H{sub 2} atmospheres, respectively. The correlation length ? increases with film thickness also with a power law according to ????d{sub f}{sup z} with exponents z?=?0.36, 0.44, and 0.57 for these three different gas atmospheres, respectively. A combination of local and non-local growth modes in 2?+?1 dimensions is discussed for the ITO growth in this work.

  16. Observation of radio frequency ring-shaped hollow cathode discharge plasma with MgO and Al electrodes for plasma processing

    SciTech Connect (OSTI)

    Ohtsu, Yasunori, E-mail: ohtsuy@cc.saga-u.ac.jp; Matsumoto, Naoki [Department of Electrical and Electronic Engineering, Graduate School of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

    2014-05-15T23:59:59.000Z

    Various high-density plasma sources have been proposed for plasma processing. Especially, the hollow cathode discharge is one of the powerful ones. In this work, radio-frequency (RF) driven ring-shaped hollow cathode discharges with high secondary-electron emission have been investigated, using an aluminum (Al) cathode, coated or not with magnesium oxide (MgO). The thickness of MgO thin film is approximately 200?nm. The RF discharge voltage for the coated cathode is almost the same as that for the uncoated one, in a wide range of Ar gas pressure, from 5.3 to 53.2?Pa. The results reveal that the plasma density has a peak at an Ar gas pressure of 10.6?Pa for both cathodes. The plasma density for the coated cathode is about 1.5–3 times higher than that for the uncoated one, at various gas pressures. To the contrary, the electron temperature for the coated cathode is lower than temperature obtained with the uncoated cathode, at various gas pressures. Radial profiles of electron saturation current, which is proportional to plasma flux, are also examined for a wide range of gas pressure. Radial profiles of electron temperature at various axial positions are almost uniform for both cathodes so that the diffusion process due to density gradient is dominant for plasma transport. The secondary electrons emitted from the coated cathode contribute to the improvement of the plasma flux radial profile obtained using the uncoated cathode.

  17. Chameleonic Radio Technical Memo No. 4

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Chameleonic Radio Technical Memo No. 4 A Comparison of Some Existing Radios with Implications 1 2 Methodology 1 3 Findings 2 4 Concluding Remarks 3 A Summary of Radio Specifications 5 B.S. consists of a dis- parate collection of radio technologies operating over a wide range of frequencies

  18. US researchers make tiny radio from 11:05AM Tuesday January 29, 2008

    E-Print Network [OSTI]

    Rogers, John A.

    the radios. They consist of two radio frequency amplifiers, a radio frequency mixer and an audio amplifier ©2008, APN Holdings NZ Limited Served by: Laurel Instance: static | 04 Feb 2008 05:36:27 | 1,877 Page 2

  19. Compact Low Frequency Radio Antenna

    DOE Patents [OSTI]

    Punnoose, Ratish J. (Hayward, CA)

    2008-11-11T23:59:59.000Z

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  20. Intelligent Radio Frequency (RF) Monitoring

    E-Print Network [OSTI]

    Kimbrough, B.

    enjoyable experiences!? David M. Armstrong Smart Wireless Gateway ? Connects WirelessHART? self- organizing networks with any host system ? Easy integration into control systems and data applications via serial and Ethernet connections ? Greater... than 99% reliability with industry proven security ? Seamless integration into automation control systems 12 ?Expect many enjoyable experiences!? David M. Armstrong Smart Wireless Gateway Interface 13 ?Expect many enjoyable experiences!? David M...

  1. Low reflectance radio frequency load

    DOE Patents [OSTI]

    Ives, R. Lawrence; Mizuhara, Yosuke M

    2014-04-01T23:59:59.000Z

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  2. Distributed Radio Interferometric Calibration

    E-Print Network [OSTI]

    Yatawatta, Sarod

    2015-01-01T23:59:59.000Z

    Increasing data volumes delivered by a new generation of radio interferometers require computationally efficient and robust calibration algorithms. In this paper, we propose distributed calibration as a way of improving both computational cost as well as robustness in calibration. We exploit the data parallelism across frequency that is inherent in radio astronomical observations that are recorded as multiple channels at different frequencies. Moreover, we also exploit the smoothness of the variation of calibration parameters across frequency. Data parallelism enables us to distribute the computing load across a network of compute agents. Smoothness in frequency enables us reformulate calibration as a consensus optimization problem. With this formulation, we enable flow of information between compute agents calibrating data at different frequencies, without actually passing the data, and thereby improving robustness. We present simulation results to show the feasibility as well as the advantages of distribute...

  3. Hybrid spread spectrum radio system

    DOE Patents [OSTI]

    Smith, Stephen F. (London, TN) [London, TN; Dress, William B. (Camas, WA) [Camas, WA

    2010-02-09T23:59:59.000Z

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  4. Fluidic patch antenna based on liquid metal alloy/single-wall carbon-nanotubes operating at the S-band frequency

    E-Print Network [OSTI]

    and scalable and can be adopted to other flexi- ble 2D and 3D devices; (ii) it allows the antenna to be inte Centre Energie, Materiaux et Telecommunications, INRS, 1650, Boulevard Lionel-Boulet Varennes, Quebec J3X, or wireless strain sensors using printed radio frequency identification (RFID) tags.3,11­13 Flexible antennas

  5. Unravelling lifecycles & physics of radio-loud AGN in the SKA era

    E-Print Network [OSTI]

    Kapi?ska, Anna D; Jackson, Carole A; An, Tao; Baan, Willem A; Jarvis, Matt J

    2014-01-01T23:59:59.000Z

    Radio-loud AGN (>10^{22} W/Hz at 1.4 GHz) will be the dominant bright source population detected with the SKA. The high resolution that the SKA will provide even in wide-area surveys will mean that, for the first time sensitive, multi-frequency total intensity and polarisation imaging of large samples of radio-loud active galactic nuclei (AGN) will become available. The unprecedented sensitivity of the SKA coupled with its wide field of view capabilities will allow identification of objects of the same morphological type (i.e. the entire FR I, low- and high-luminosity FR II, disturbed morphology as well as weak radio-emitting AGN populations) up to high redshifts (z~4 and beyond), and at the same stage of their lives, from the youngest CSS/GPS sources to giant and fading (dying) sources, through to those with restarted activity radio galaxies and quasars. Critically, the wide frequency coverage of the SKA will permit analysis of same-epoch rest-frame radio properties, and the sensitivity and resolution will a...

  6. International Workshop on Radio Frequency Identification (RFID) and Wireless Sensors 11-13 November 2005, Indian Institute of Technology, Kanpur, India

    E-Print Network [OSTI]

    California at Los Angeles, University of

    Infrastructure B.S. Prabhu, Xiaoyong Su, Charlie Qiu, Harish Ramamurthy, Peter Chu, Rajit Gadh Wireless Internet

  7. The Radio Frequency Identification enabled logistics process for supply chain event management from China to the United States via Hong Kong

    E-Print Network [OSTI]

    Han, Taehee

    2005-01-01T23:59:59.000Z

    This thesis reviews the current logistics processes and issues for container shipments in the supply chain. In particular, the problems associated with container shipments from China to the US, via the Hong Kong Port, ...

  8. Radio Broadcasts from Superconducting Strings

    E-Print Network [OSTI]

    Yi-Fu Cai; Eray Sabancilar; Daniele A. Steer; Tanmay Vachaspati

    2012-05-14T23:59:59.000Z

    Superconducting cosmic strings can give transient electromagnetic signatures that we argue are most evident at radio frequencies. We investigate the three different kinds of radio bursts from cusps, kinks, and kink-kink collisions on superconducting strings. We find that the event rate is dominated by kink bursts in a range of parameters that are of observational interest, and can be quite high (several a day at 1 Jy flux) for a canonical set of parameters. In the absence of events, the search for radio transients can place stringent constraints on superconducting cosmic strings.

  9. A newsletter for non-scientists (and scientists) interested in MAGIC Radars transmit pulses of radio waves of a given frequency and receive signals that are

    E-Print Network [OSTI]

    the Doppler effect, named after Christian Doppler, an Austrian physicist of the 19th century. Everyone sizes of raindrops. The Doppler effect pertains to the change in frequency of a wave emitted-- this is the Doppler effect in a nutshell. The amount by which the pitch is greater or lower, called the Doppler shift

  10. 27/10/2010 12:48AGU: Highlatitude geomagnetically induced current events observed on very low frequency radio wave receiver systems Page 1 of 2http://europa.agu.org/?view=article&uri=/journals/rs/rs1002/2009RS004215/2009RS004215.xml&t=

    E-Print Network [OSTI]

    Ulich, Thomas

    27/10/2010 12:48AGU: Highlatitude geomagnetically induced current events observed on very low Abstract Highlatitude geomagnetically induced current events observed on very low frequency radio wave characteristics. Finally, we compared in detail the geomagnetic induced current (GIC) in the Scottish power system

  11. Radio Pulsars

    E-Print Network [OSTI]

    Beskin, V S; Gwinn, C R; Tchekhovskoy, A

    2015-01-01T23:59:59.000Z

    Almost 50 years after radio pulsars were discovered in 1967, our understanding of these objects remains incomplete. On the one hand, within a few years it became clear that neutron star rotation gives rise to the extremely stable sequence of radio pulses, that the kinetic energy of rotation provides the reservoir of energy, and that electromagnetic fields are the braking mechanism. On the other hand, no consensus regarding the mechanism of coherent radio emission or the conversion of electromagnetic energy to particle energy yet exists. In this review, we report on three aspects of pulsar structure that have seen recent progress: the self-consistent theory of the magnetosphere of an oblique magnetic rotator; the location, geometry, and optics of radio emission; and evolution of the angle between spin and magnetic axes. These allow us to take the next step in understanding the physical nature of the pulsar activity.

  12. Underground radio technology saves miners and emergency response...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data...

  13. Synchronization and Characterization of an Ultra-Short Laser for Photoemission and Electron-Beam Diagnostics Studies at a Radio Frequency Photoinjector

    SciTech Connect (OSTI)

    Maxwell, Timothy; Ruan, Jinhao; Piot, Philippe; Lumpkin, Alex; ,

    2012-03-01T23:59:59.000Z

    A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.

  14. Synchronization and Characterization of an Ultra-Short Laser for Photoemission and Electron-Beam Diagnostics Studies at a Radio Frequency Photoinjector

    E-Print Network [OSTI]

    Maxwell, Timothy; Piot, Philippe; Lumpkin, Alex

    2012-01-01T23:59:59.000Z

    A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.

  15. Hybrid spread spectrum radio system

    DOE Patents [OSTI]

    Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

    2010-02-02T23:59:59.000Z

    Systems and methods are described for hybrid spread spectrum radio systems. A method includes modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control an amplification circuit that provides a gain to the signal. Another method includes: modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control a fast hopping frequency synthesizer; and fast frequency hopping the signal with the fast hopping frequency synthesizer, wherein multiple frequency hops occur within a single data-bit time.

  16. Commercial Mobile Radio Service (WRI CMRS)

    E-Print Network [OSTI]

    Commercial Mobile Radio Service (WRI ­ CMRS) Commercial Motor Vehicle Roadside Technology Corridor Safety Technology Showcase October 14, 2010 Commercial Motor Vehicle Roadside Technology Corridor #12 caused by higher frequency of roadside safety inspections using wireless technologies. · Benefits

  17. Gravitational Redshift Experiment with the Space Radio Telescope RadioAstron

    E-Print Network [OSTI]

    D. Litvinov; N. Bartel; K. Belousov; M. Bietenholz; A. Biriukov; A. Fionov; A. Gusev; V. Kauts; A. Kovalenko; V. Kulagin; N. Poraiko; V. Rudenko

    2015-03-12T23:59:59.000Z

    A unique test of general relativity is possible with the space radio telescope RadioAstron. The ultra-stable on-board hydrogen maser frequency standard and the highly eccentric orbit make RadioAstron an ideal instrument for probing the gravitational redshift effect. Large gravitational potential variation, occurring on the time scale of $\\sim$24 hr, causes large variation of the on-board H-maser clock rate, which can be detected via comparison with frequency standards installed at various ground radio astronomical observatories. The experiment requires specific on-board hardware operating modes and support from ground radio telescopes capable of tracking the spacecraft continuously and equipped with 8.4 or 15 GHz receivers. Our preliminary estimates show that $\\sim$30 hr of the space radio telescope's observational time are required to reach $\\sim 2\\times10^{-5}$ accuracy in the test, which would constitute a factor of 10 improvement over the currently achieved best result.

  18. Gravitational Redshift Experiment with the Space Radio Telescope RadioAstron

    E-Print Network [OSTI]

    Litvinov, D; Belousov, K; Bietenholz, M; Biriukov, A; Fionov, A; Gusev, A; Kauts, V; Kovalenko, A; Kulagin, V; Poraiko, N; Rudenko, V

    2015-01-01T23:59:59.000Z

    A unique test of general relativity is possible with the space radio telescope RadioAstron. The ultra-stable on-board hydrogen maser frequency standard and the highly eccentric orbit make RadioAstron an ideal instrument for probing the gravitational redshift effect. Large gravitational potential variation, occurring on the time scale of $\\sim$24 hr, causes large variation of the on-board H-maser clock rate, which can be detected via comparison with frequency standards installed at various ground radio astronomical observatories. The experiment requires specific on-board hardware operating modes and support from ground radio telescopes capable of tracking the spacecraft continuously and equipped with 8.4 or 15 GHz receivers. Our preliminary estimates show that $\\sim$30 hr of the space radio telescope's observational time are required to reach $\\sim 2\\times10^{-5}$ accuracy in the test, which would constitute a factor of 10 improvement over the currently achieved best result.

  19. Radio AGN evolution with low frequency radio surveys 

    E-Print Network [OSTI]

    Ker, Louise Moira

    2013-07-01T23:59:59.000Z

    Supermassive black holes are leading candidates for the regulation of galaxy growth and evolution over cosmic time, via ‘feedback’ processes, whereby outflows from the Active Galactic Nuclei (AGN) halt star formation ...

  20. Telecommunications Radio Lease

    E-Print Network [OSTI]

    Telecommunications Radio Lease 1. Fax completed form to 979.847.1111. 2. If you do not receive. Note: There is an air time charge for the use of the radios. Radio lease rates depend on the radio type to any of the radios, chargers and accessories until signed back over to the Telecommunications office

  1. Suppression of automotive radio frequency interference 

    E-Print Network [OSTI]

    McLaughlin, Cleon Crosby

    1969-01-01T23:59:59.000Z

    of the spark plug and dlstribijtor gap brcakdo'sns is r epr educed by sc'ri tchi ng from an equiva- lent capacj cor befo'. gap Lreakdo'sn to an equivalent gap res j stance aiel:i ndu'':!nce dur. , nrJ b i akdo~sn This capa- bil i tV i ' . &ne &of the major... into lumped clem!'. nts and by providing equiva. 'ent cir uits for the disirib!!tor and spark plug gapa in both co! ducting and non ? conducti. ng states. Unfor unatcly, the state variable rr. odel recuires a grea. i deal of computer time in order...

  2. Suppression of automotive radio frequency interference

    E-Print Network [OSTI]

    McLaughlin, Cleon Crosby

    1969-01-01T23:59:59.000Z

    . e manu fac i ur ers began putt: i ng re. ! '= t o '. '' o!& " . '1 s . ance &v'xi &'- i nto Lhe 1g?1 tao & sys tc. ", &'' they found I&ha L- suf F i ?i = . . . i& sup&!ze =, sion was ob tai ned Lo mc?t i&i!e sp&!&! i f i ?etio?s = nd r equi...

  3. Dielectric supported radio-frequency cavities

    DOE Patents [OSTI]

    Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)

    2000-01-01T23:59:59.000Z

    A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

  4. Phase manipulation for efficient radio frequency transmission

    E-Print Network [OSTI]

    Barton, Taylor Wallis

    2012-01-01T23:59:59.000Z

    Power amplifiers (PAs) for microwave communications are generally the most power-hungry element of a transmitter. High linearity is required for modern digital communications standards, and often is achieved at the expense ...

  5. Radio frequency quadrupole resonator for linear accelerator

    DOE Patents [OSTI]

    Moretti, Alfred (Downers Grove, IL)

    1985-01-01T23:59:59.000Z

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  6. Radio frequency focused interdigital linear accelerator

    DOE Patents [OSTI]

    Swenson, Donald A.; Starling, W. Joel

    2006-08-29T23:59:59.000Z

    An interdigital (Wideroe) linear accelerator employing drift tubes, and associated support stems that couple to both the longitudinal and support stem electromagnetic fields of the linac, creating rf quadrupole fields along the axis of the linac to provide transverse focusing for the particle beam. Each drift tube comprises two separate electrodes operating at different electrical potentials as determined by cavity rf fields. Each electrode supports two fingers, pointing towards the opposite end of the drift tube, forming a four-finger geometry that produces an rf quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to one half of the particle wavelength .beta..lamda., where .beta. is the particle velocity in units of the velocity of light and .lamda. is the free space wavelength of the rf. Particles are accelerated in the gaps between drift tubes. The particle beam is focused in regions inside the drift tubes.

  7. Wide band stepped frequency ground penetrating radar

    DOE Patents [OSTI]

    Bashforth, M.B.; Gardner, D.; Patrick, D.; Lewallen, T.A.; Nammath, S.R.; Painter, K.D.; Vadnais, K.G.

    1996-03-12T23:59:59.000Z

    A wide band ground penetrating radar system is described embodying a method wherein a series of radio frequency signals is produced by a single radio frequency source and provided to a transmit antenna for transmission to a target and reflection therefrom to a receive antenna. A phase modulator modulates those portions of the radio frequency signals to be transmitted and the reflected modulated signal is combined in a mixer with the original radio frequency signal to produce a resultant signal which is demodulated to produce a series of direct current voltage signals, the envelope of which forms a cosine wave shaped plot which is processed by a Fast Fourier Transform Unit 44 into frequency domain data wherein the position of a preponderant frequency is indicative of distance to the target and magnitude is indicative of the signature of the target. 6 figs.

  8. Wide band stepped frequency ground penetrating radar

    DOE Patents [OSTI]

    Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

    1996-01-01T23:59:59.000Z

    A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

  9. Modulate Internet Radio Into FM Using GNU Radio

    E-Print Network [OSTI]

    Yu, Chansu

    1 Modulate Internet Radio Into FM Using GNU Radio By: Elie Salameh Outline. · Fm in gnu radio · Audio Streams in Internet Radio · Gnu & Audio Files · Sox command · Playlist ".pls" · Recording internet radio #12;2 Project description · Using gnu radio to modulate internet radio into fm. · Using usrp

  10. Telecommunications Radio Rental

    E-Print Network [OSTI]

    Telecommunications Radio Rental 1. Fax completed form to 979.847.1111. 2. If you do not receive://telecom.tamu.edu/Accounts/Rate_Information.php). There is an air time charge for the use of the radios. Rental radios will be pro-rated per radio per daily usage of the radios, chargers and accessories until signed back over to the Telecommunications office. Amount

  11. > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 1 Abstract--In this letter, a novel linear frequency-domain

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    --In this letter, a novel linear frequency-domain compensation (FDC) of the resonant cavity light emitting diode emitting diodes (RC-LED) have been largely adopted in POF communications with on-off-keying modulation insensitivity, which are extremely suitable for optical home networking [2]. The low-cost resonant cavity light

  12. Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera

    SciTech Connect (OSTI)

    Kent Marlett, Bechtel Nevada; Ke-Xun Sun Bechtel Nevada

    2004-09-23T23:59:59.000Z

    This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output.

  13. Vital Alert's C1000 mine and tunnel radios use magnetic induction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data...

  14. The First Steps of Radio Astronomy in Czestochowa

    E-Print Network [OSTI]

    M. Jarosik; S. Starzynski; M. Szczesniak; R. Szczesniak; A. Ceglarek

    2007-12-10T23:59:59.000Z

    In the paper, technical documentation and the principle of operation is presented. "KLAUDIA" radio telescope was built in Rabka in 2007 and it is used to receive secondary radio waves, emitted by the Earth's ionosphere at frequency of 40 kHz.

  15. Automatic calibration of modulated fractional-N frequency synthesizers

    E-Print Network [OSTI]

    McMahill, Dan

    2001-01-01T23:59:59.000Z

    The focus of this research has been the development of a low power, radio frequency transmitter architecture. Specifically, a technique for in service automatic calibration of a modulated phase locked loop (PLL) frequency ...

  16. Energy Efficient Radio Resource

    E-Print Network [OSTI]

    Yanikomeroglu, Halim

    Energy Efficient Radio Resource Management in a Coordinated Multi-Cell Distributed Antenna System Omer HALILOGLU Introduction System Model Performance Evaluation Conclusion References Energy Efficient Hacettepe University 5 September 2014 Omer HALILOGLU (Hacettepe University) Energy Efficient Radio Resource

  17. THE FREQUENCY AGILE SOLAR RADIOTELESCOPE T. S. Bastian

    E-Print Network [OSTI]

    Edgemont Road, Charlottesville, VA 22903, USA ABSTRACT The Frequency Agile Solar Radiotelescope (FASR1 THE FREQUENCY AGILE SOLAR RADIOTELESCOPE T. S. Bastian National Radio Astronomy Observatory, 520), a telescope concept currently under study, will be a ground based solar-dedicated radio telescope designed

  18. Preparing a public database of radio sources

    E-Print Network [OSTI]

    H. Andernach; S. A. Trushkin; A. G. Gubanov; O. V. Verkhodanov; V. B. Titov; A. Micol

    1996-07-22T23:59:59.000Z

    We have collected the largest existing set of radio source lists in machine-readable form: 320 tables with 1.75 million records. Only a minor fraction of these is accessible via public databases. We describe our plans to make this huge amount of heterogeneous data accessible in a homogeneous way via the World Wide Web, with reliable cross-identifications, and searchable by various observables.

  19. NATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE, VIRGINIA

    E-Print Network [OSTI]

    Groppi, Christopher

    of operating 135 cryogenic receivers on the VIA. First, a review of recent progress in cryogenically-cooled have been developed for use in a new radio astronomy system [1]. This new system is called the Very other frequencies utilize HEMT amplifiers cooled to 13 K in separate dewars at the Cassegrain focus

  20. An accretion disk and radio spectra of pulsars

    E-Print Network [OSTI]

    F. V. Prigara

    2003-07-25T23:59:59.000Z

    On the basis of the unified model of compact radio sources, the dependence of a turnover frequency in the smoothed radio spectrum of a pulsar upon the ratio of the dispersion measure to the period of a pulsar is obtained. This relation is produced by the radial density wave in the accretion disk surrounding a pulsar. The unified model of compact radio sources gives also the smoothed spectral indices of radio emission from pulsars as $\\alpha=2$ for the gaseous disk with the temperature profile T=const and $\\alpha=3$ for the gaseous disk with the pressure profile P=const ($F_{\

  1. Radio Observations of the Hubble Deep Field South Region IV: Optical Properties of the Faint Radio Population

    E-Print Network [OSTI]

    M. T. Huynh; C. A. Jackson; R. P. Norris; A. Fernandez-Soto

    2008-03-31T23:59:59.000Z

    The Australia Telescope Hubble Deep Field-South (ATHDFS) survey of the Hubble Deep Field South reaches sensitivities of ~10 miceoJyJy at 1.4, 2.5, 5.2 and 8.7 GHz, making the ATHDFS one of the deepest surveys ever performed with the Australia Telescope Compact Array. Here we present the optical identifications of the ATHDFS radio sources using data from the literature. We find that ~66% of the radio sources have optical counterparts to I = 23.5 mag. Deep HST imaging of the area identifies a further 12% of radio sources. We present new spectroscopic observations for 98 of the radio sources, and supplement these spectroscopic redshifts with photometric ones calculated from 5-band optical imaging. The host galaxy colors and radio-to-optical ratios indicate that low luminosity (or "radio quiet") AGN make up a significant proportion of the sub-mJy radio population, a result which is in accordance with a number of other deep radio studies. The radio-to-optical ratios of the bright (S_1.4GHz > 1 mJy) sources is consistent with a bimodal distribution.

  2. Radio flares from gamma-ray bursts

    E-Print Network [OSTI]

    Kopac, D; Kobayashi, S; Virgili, F J; Harrison, R; Japelj, J; Guidorzi, C; Melandri, A; Gomboc, A

    2015-01-01T23:59:59.000Z

    We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parametrization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. (2007) and Melandri et al. (2010) in which the typical frequency of the reverse shock was suggested to lie at radio, rather than optical wavelengths at early times, we show that the brightest and most distinct reverse-shock radio signatures are detectable up to 0.1 -- 1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later opt...

  3. presents... CJSF Radio, SFU's Campus and Community radio

    E-Print Network [OSTI]

    presents... CJSF Radio, SFU's Campus and Community radio station is offering their Radio Kids Camp once again this year, for kids aged 8-12! CJSF 90.1fm is a radio station which promotes local around Storytelling. With radio as a way to express their voice, campers will learn innovative skills

  4. NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia

    E-Print Network [OSTI]

    Groppi, Christopher

    NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia Electronics Division Internal Report No. 109 BATTERY PACK FOR HEWLETT-PACKARD 5065A RUBIDIUM FREQUENCY STANDARD Michael Balister OCTOBER 1971 NUMBER OF COPIES: 150 #12;BATTERY PACK FOR HEWLETT-PACKARD 5065A RUBIDIUM FREQUENCY STANDARD

  5. TACTICAL RADIO OPERATIONS August 2009

    E-Print Network [OSTI]

    US Army Corps of Engineers

    FM 6-02.53 TACTICAL RADIO OPERATIONS August 2009 DISTRIBUTION RESTRICTION. Approved for public August 2009 TACTICAL RADIO OPERATIONS Contents Page PREFACE ...........................................................................................................viii Chapter 1 APPLICATIONS FOR TACTICAL RADIO DEPLOYMENT.............................. 1-1 Modularity

  6. Spectral indices of Galactic radio loops between 1420, 820 and 408 MHz

    E-Print Network [OSTI]

    V. Borka

    2007-02-10T23:59:59.000Z

    In this paper the average brightness temperatures and surface brightnesses at 1420, 820 and 408 MHz of the six main Galactic radio-continuum loops are derived, as are their radio spectral indices. The temperatures and surface brightnesses of the radio loops are computed using data taken from radio continuum surveys at 1420, 820 and 408 MHz. We have demonstrated the reality of Loops V and VI and present diagrams of their spectra for the first time. We derived the radio spectral indices of Galactic radio loops from radio surveys at three frequencies (1420, 820 and 408 MHz) and confirm them to be non-thermal sources. Diameters and distances of Loops I-VI were also calculated. The results obtained are in good agreement with current theories of supernova remnant (SNR) evolution and suggest that radio loops may have a SNR origin.

  7. Cognitive Radio will revolutionize American transportation

    ScienceCinema (OSTI)

    None

    2013-12-06T23:59:59.000Z

    Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

  8. Cognitive Radio will revolutionize American transportation

    SciTech Connect (OSTI)

    None

    2013-07-22T23:59:59.000Z

    Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

  9. MOS: A critical tool for current and future radio surveys

    E-Print Network [OSTI]

    Smith, Daniel J B

    2015-01-01T23:59:59.000Z

    Since radio continuum observations are not affected by dust obscuration, they are of immense potential diagnostic power as cosmological probes and for studying galaxy formation and evolution out to high redshifts. However, the power-law nature of radio frequency spectra ensures that ancillary spectroscopic information remains critical for studying the properties of the faint radio sources being detected in rapidly-increasing numbers on the pathway to the Square Kilometre Array. In this contribution, I present some of the key scientific motivations for exploiting the immense synergies between radio continuum observations and multi-object spectroscopic surveys. I review some of the ongoing efforts to obtain the spectra necessary to harness the huge numbers of star-forming galaxies and AGN that current and future radio surveys will detect. I also touch on the WEAVE-LOFAR survey, which will use the WEAVE spectrograph currently being built for the William Herschel Telescope to target hundreds of thousands of low f...

  10. The UCLA -Wireless Internet for the Mobile Enterprise Consortium (WINMEC) is pleased to announce its 2004 RFID FORUM (Radio Frequency Identification) (http://www.winmec.ucla.edu/rfid/2004/), to be held at UCLA, Los Angeles, California on

    E-Print Network [OSTI]

    California at Los Angeles, University of

    , Manager, Retail Solutions Group, Cisco Systems, Inc. - Rajit Gadh, Professor & Director, UCLA - WINMEC

  11. Studying the properties of the radio emitter in LS 5039

    E-Print Network [OSTI]

    V. Bosch-Ramon

    2008-11-06T23:59:59.000Z

    LS 5039 is an X-ray binary that presents non-thermal radio emission. The radiation at $\\sim 5$ GHz is quite steady and optically thin, consisting on a dominant core plus an extended jet-like structure. There is a spectral turnover around 1 GHz, and evidence of variability at timescales of 1 yr at 234 MHz. We investigate the radio emitter properties using the available broadband radio data, and assuming two possible scenarios to explain the turnover: free-free absorption in the stellar wind, or synchrotron self-absorption. We use the relationships between the turnover frequency, the stellar wind density, the emitter location, size and magnetic field, and the Lorentz factor of the emitting electrons, as well as a reasonable assumption on the energy budget, to infer the properties of the low-frequency radio emitter. Also, we put this information in context with the broadband radio data. The location and size of the low-frequency radio emitter can be restricted to $\\ga$ few AU from the primary star, its magnetic field to $\\sim 3\\times 10^{-3}-1$ G, and the electron Lorentz factors to $\\sim 10-100$. The observed variability of the extended structures seen with VLBA would point to electron bulk velocities $\\ga 3\\times 10^8$ cm s$^{-1}$, whereas much less variable radiation at 5 GHz would indicate velocities for the VLBA core $\\la 10^8$ cm s$^{-1}$. The emission at 234 MHz in the high state would mostly come from a region larger than the dominant broadband radio emitter. We suggest a scenario in which secondary pairs, created via gamma-ray absorption and moving in the stellar wind, are behind the steady broadband radio core, whereas the resolved jet-like radio emission would come from a collimated, faster, outflow.

  12. Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio

    E-Print Network [OSTI]

    Sandercock, Brett K.

    Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio Impacts the duration of transmitter attachment and minimizing the impacts of radios on the behavior and demography of the study animal. We tested 4 methods of radio attachment for a breeding population of upland sandpipers

  13. Satellite Radio: Its Global Impact

    E-Print Network [OSTI]

    Udgaonkar, Jayant B.

    Satellite Radio: Its Global Impact TIFR Alumni Lecture By S.Rangarajan #12;1 A wonder called RADIO "No wonder so many physicists started as radio tinkers, and no wonder, before physicist became on Richard Feynmann We will stick to the definition of Radio as · Wireless Audio Delivery ·Listener cannot

  14. Hop Reservation Multiple Access (HRMA) for Multichannel Packet Radio Networks Zhenyu Tang and J. J. Garcia-Luna-Aceves

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Hop Reservation Multiple Access (HRMA) for Multichannel Packet Radio Networks Zhenyu Tang and J. J Reservation Mul- tiple Access (HRMA) for packet-radio networks is introduced, specified and analyzed. HRMA necessary for frequency hopping. HRMA allows a pair of communicating nodes to reserve a frequency hop

  15. Radar network communication through sensing of frequency hopping

    DOE Patents [OSTI]

    Dowla, Farid; Nekoogar, Faranak

    2013-05-28T23:59:59.000Z

    In one embodiment, a radar communication system includes a plurality of radars having a communication range and being capable of operating at a sensing frequency and a reporting frequency, wherein the reporting frequency is different than the sensing frequency, each radar is adapted for operating at the sensing frequency until an event is detected, each radar in the plurality of radars has an identification/location frequency for reporting information different from the sensing frequency, a first radar of the radars which senses the event sends a reporting frequency corresponding to its identification/location frequency when the event is detected, and all other radars in the plurality of radars switch their reporting frequencies to match the reporting frequency of the first radar upon detecting the reporting frequency switch of a radar within the communication range. In another embodiment, a method is presented for communicating information in a radar system.

  16. Applications and noise properties of high repetition rate : TiSapphire frequency combs

    E-Print Network [OSTI]

    Benedick, Andrew John

    2011-01-01T23:59:59.000Z

    Femtosecond mode-locked lasers are a unique laser technology due to their broad optical bandwidth and potential for linking the optical and radio frequency domains when these lasers are configured as frequency combs. ...

  17. Design of frequency synthesizers for short range wireless transceivers

    E-Print Network [OSTI]

    Valero Lopez, Ari Yakov

    2004-09-30T23:59:59.000Z

    reduction while providing a high level of integration. The radio section of the devices designed to establish communications using these standards is the limiting factor for the power reduction efforts. A key building block in a transceiver is the frequency...

  18. Cognitive Radio Networks as Sensor Networks

    E-Print Network [OSTI]

    Bandari, Dorna; Yang, Seung R.; Zhao, Yue; Pottie, Gregory

    2007-01-01T23:59:59.000Z

    assuming the cognitive radios know their own coordinates.Networked Sensing Cognitive Radio Networks As SensorIntroduction: Cognitive Radio (CR) Networks The Need For

  19. Ion cyclotron range of frequencies heating of plasma with small impurity production

    DOE Patents [OSTI]

    Ohkawa, Tihiro (La Jolla, CA)

    1987-01-01T23:59:59.000Z

    Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.

  20. Angular clustering in the SUMSS radio survey

    E-Print Network [OSTI]

    Chris Blake; Tom Mauch; Elaine M. Sadler

    2003-10-05T23:59:59.000Z

    We measure the angular correlation function of radio galaxies selected by the 843 MHz Sydney University Molonglo Sky Survey (SUMSS). We find that the characteristic imprint of large-scale structure is clearly detectable, and that the survey is very uniform. Through comparison with similar analyses for other wide-area radio surveys - the 1400 MHz NRAO VLA Sky Survey (NVSS) and the 325 MHz Westerbork Northern Sky Survey (WENSS) - we are able to derive consistent angular clustering parameters, including a steep slope for the clustering function, $w(\\theta) \\propto \\theta^{-1.1}$. We revise upwards previous estimates of the NVSS clustering amplitude, and find no evidence for dependence of clustering properties on radio frequency. It is important to incorporate the full covariance matrix when fitting parameters to the measured correlation function. Once the redshift distribution for mJy radio galaxies has been determined, these projected clustering measurements will permit a robust description of large-scale structure at $z \\sim 0.8$, the median redshift of the sources.

  1. Detecting Radio Emission from Cosmic Ray Air Showers and Neutrinos with a Digital Radio Telescope

    E-Print Network [OSTI]

    Heino Falcke; Peter Gorham

    2002-07-10T23:59:59.000Z

    We discuss the possibilities of measuring ultra-high energy cosmic rays and neutrinos with radio techniques. We review a few of the properties of radio emission from cosmic ray air showers and show how these properties can be explained by coherent ``geosynchrotron'' emission from electron-positron pairs in the shower as they move through the geomagnetic field. This should allow one to use the radio emission as a useful diagnostic tool for cosmic ray research. A new generation of digital telescopes will make it possible to study this radio emission in greater detail. For example, the planned Low-Frequency Array (LOFAR), operating at 10-200 MHz, will be an instrument uniquely suited to study extensive air showers and even detect neutrino-induced showers on the moon. We discuss sensitivities, count rates and possible detection algorithms for LOFAR and a currently funded prototype station LOPES. This should also be applicable to other future digital radio telescopes such as the Square-Kilometer-Array (SKA). LOFAR will be capable of detecting air-shower radio emission from >2*10^14 eV to ~10^20 eV. The technique could be easily extended to include air shower arrays consisting of particle detectors (KASCADE, Auger), thus providing crucial additional information for obtaining energy and chemical composition of cosmic rays. It also has the potential to extend the cosmic ray search well beyond an energy of 10^21 eV if isotropic radio signatures can be found. Other issues that LOFAR can address are to determine the neutral component of the cosmic ray spectrum, possibly look for neutron bursts, and do actual cosmic ray astronomy.

  2. Detecting Radio Emission from Cosmic Ray Air Showers and Neutrinos with a Digital Radio Telescope

    E-Print Network [OSTI]

    Falcke, H; Falcke, Heino; Gorham, Peter

    2003-01-01T23:59:59.000Z

    We discuss the possibilities of measuring ultra-high energy cosmic rays and neutrinos with radio techniques. We review a few of the properties of radio emission from cosmic ray air showers and show how these properties can be explained by coherent ``geosynchrotron'' emission from electron-positron pairs in the shower as they move through the geomagnetic field. This should allow one to use the radio emission as a useful diagnostic tool for cosmic ray research. A new generation of digital telescopes will make it possible to study this radio emission in greater detail. For example, the planned Low-Frequency Array (LOFAR), operating at 10-200 MHz, will be an instrument uniquely suited to study extensive air showers and even detect neutrino-induced showers on the moon. We discuss sensitivities, count rates and possible detection algorithms for LOFAR and a currently funded prototype station LOPES. This should also be applicable to other future digital radio telescopes such as the Square-Kilometer-Array (SKA). LOFAR...

  3. Radio emissions from terrestrial gamma-ray flashes Joseph R. Dwyer1

    E-Print Network [OSTI]

    Cummer, Steven A.

    . Introduction 1.1. TGF Theory Overview [2] Terrestrial gamma-ray flashes (TGFs) are bright bursts of gamma raysRadio emissions from terrestrial gamma-ray flashes Joseph R. Dwyer1 and Steven A. Cummer2 Received frequency (RF) emissions by terrestrial gamma-ray flashes (TGFs) is developed. These radio emissions, which

  4. Green radio despite "Dirty RF" front-end Myriam Ariaudo*1

    E-Print Network [OSTI]

    Fijalkow, Inbar

    Green radio despite "Dirty RF" front-end Myriam Ariaudo*1 , Inbar Fijalkow1 , Jean-Luc Gautier1 in order to contribute in a Green radio development. In fact, the effects of typical RF imperfections, like algorithms are applied. Such algorithms enable Green applications (e.g., Orthogonal Frequency Division

  5. Z mode waves as the source of Saturn narrowband radio emissions

    E-Print Network [OSTI]

    Gurnett, Donald A.

    Z mode waves as the source of Saturn narrowband radio emissions ShengYi Ye,1 J. D. Menietti,1 G emissions observed by the Cassini Radio and Plasma Waves Science (RPWS) instrument during high latitude perikrone passes. The narrowband emissions observed below the local electron cyclotron frequency ( fce

  6. Radio Afterglows and Host Galaxies of Gamma-Ray Bursts

    E-Print Network [OSTI]

    Li, Long-Biao; Huang, Yong-Feng; Wu, Xue-Feng; Kong, Si-Wei; Li, Di; Chang, Heon-Young; Choi, Chul-Sung

    2015-01-01T23:59:59.000Z

    Considering the contribution of the emission from the host galaxies of gamma-ray bursts (GRBs) to the radio afterglows, we investigate the effect of host galaxies on observations statistically. For the three types of events, e.g. low-luminosity, standard and high-luminosity GRBs, it is found that a tight correlation exists between the ratio of the radio flux (RRF) of host galaxy to the total radio peak emission and the observational frequency. Especially, toward lower frequencies, the contribution from the host increases significantly. The correlation can be used to get a useful estimate for the radio brightness of those host galaxies which only have very limited radio afterglow data. Using this prediction, we re-considered the theoretical radio afterglow light curves for four kinds of events, i.e. high-luminosity, low-luminosity, standard and failed GRBs, taking into account the contribution from the host galaxies and aiming at exploring the detectability of these events by the Five-hundred-meter Aperture Sp...

  7. Deep ATLAS radio observations of the CDFS-SWIRE field

    E-Print Network [OSTI]

    Ray P. Norris; Jose Afonso; Phil N. Appleton; Brian J. Boyle; Paolo Ciliegi; Scott M. Croom; Minh T. Huynh; Carole A. Jackson; Anton M. Koekemoer; Carol J. Lonsdale; Enno Middelberg; Bahram Mobasher; Seb J. Oliver; Mari Polletta; Brian D. Siana; Ian Smail; Maxim A. Voronkov

    2006-10-18T23:59:59.000Z

    We present the first results from the Australia Telescope Large Area Survey (ATLAS), which consist of deep radio observations of a 3.7 square degree field surrounding the Chandra Deep Field South, largely coincident with the infrared Spitzer Wide-Area Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photometry data from SWIRE, and ground-based optical spectroscopy. A total of 784 radio components are identified, corresponding to 726 distinct radio sources, nearly all of which are identified with SWIRE sources. Of the radio sources with measured redshifts, most lie in the redshift range 0.5-2, and include both star-forming galaxies and active galactic nuclei (AGN). We identify a rare population of infrared-faint radio sources which are bright at radio wavelengths but are not seen in the available optical, infrared, or X-ray data. Such rare classes of sources can only be discovered in wide, deep surveys such as this.

  8. eRadio : empowerment through community Web radio

    E-Print Network [OSTI]

    Gomez-Monroy, Carla, 1977-

    2004-01-01T23:59:59.000Z

    The eRadio project proposes to be an effective aid to increase interaction and reduce alienation among the members of dispersed communities by using a holistic approach to participatory and interactive web radio-production, ...

  9. Antenna system characteristic and solar radio burst observation

    E-Print Network [OSTI]

    Li, Sha; Chen, Zhijun; Wang, Wei; Liu, Donghao

    2015-01-01T23:59:59.000Z

    Chinese Spectral Radio Heliograph (CSRH) is an advanced aperture synthesis solar radio heliograph, developed by National Astronomical Observatories, Chinese Academy of Sciences independently. It consists of 100 reflector antennas, which are grouped into two antenna arrays (CSRH-I and CSRH-II) for low and high frequency bands respectively. The frequency band of CSRH-I is 0.4-2GHz and for CSRH-II, the frequency band is 2-15GHz. In the antenna and feed system, CSRH uses an Eleven feed to receive signals coming from the Sun, the radiation pattern with lower side lobe and back lobe of the feed is well radiated. The characteristics of gain G and antenna noise temperature T effect the quality of solar radio imaging. For CSRH, measured G is larger than 60 dBi and $ T $ is less than 120K, after CSRH-I was established, we have successfully captured a solar radio burst between 1.2-1.6GHz on November 12, 2010 through this instrument and this event was confirmed through the observation of Solar Broadband Radio Spectromete...

  10. First `Winged' and `X'-shaped Radio Source Candidates

    SciTech Connect (OSTI)

    Cheung, C.C.

    2007-01-22T23:59:59.000Z

    A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic radio data are presented. From the limited resolution FIRST images ({approx} 5''), we can already confidently classify a sufficient number of these objects as having the characteristic wing lengths >80% of the active lobes to more than double the number of known X-shaped radio sources. We have also included as candidates, radio sources with shorter wings (<80% wing to lobe length ratios), or simply ''winged'' sources, as it is probable that projection effects are important. Finally, among the candidates are four quasars (z=0.37 to 0.84), and several have morphologies suggestive of Fanaroff-Riley type-I (low-power) radio galaxies. While followup observations are necessary to confirm these identifications, this stresses the importance of source orientation and imaging limitations in finding these enigmatic objects.

  11. The radio structure of radio-quiet quasars

    E-Print Network [OSTI]

    Christian Leipski; Heino Falcke; Nicola Bennert; Susanne Huettemeister; ;

    2006-06-21T23:59:59.000Z

    We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies. We present and analyse high-sensitivity VLA radio continuum images of 14 radio-quiet quasars and six Seyfert galaxies. Many of the low redshift radio-quiet quasars show radio structures that can be interpreted as jet-like outflows. However, the detection rate of extended radio structures on arcsecond scales among our sample decreases with increasing redshift and luminosity, most likely due to a lack of resolution. The morphologies of the detected radio emission indicate strong interactions of the jets with the surrounding medium. We also compare the radio data of seven quasars with corresponding HST images of the [OIII] emitting narrow-line region (NLR). We find that the scenario of interaction between the radio jet and the NLR gas is confirmed in two sources by structures in the NLR gas distribution as previously known for Seyfert galaxies. The extended radio structures of radio-quiet quasars at sub-arcsecond resolution are by no means different from that of Seyferts. Among the luminosities studied here, the morphological features found are similar in both types of objects while the overall size of the radio structures increases with luminosity. This supports the picture where radio-quiet quasars are the scaled-up versions of Seyfert galaxies. In addition to known luminosity relations we find a correlation of the NLR size and the radio size shared by quasars and Seyferts.

  12. Some Fundamental Limitations for Cognitive Radio

    E-Print Network [OSTI]

    Sahai, Anant

    ' & $ % Some Fundamental Limitations for Cognitive Radio Anant Sahai Wireless Foundations, UCB EECS program November 1 at BWRC Cognitive Radio Workshop #12;' & $ % Outline 1. Why cognitive radios? 2 November 1 at BWRC Cognitive Radio Workshop #12;' & $ % Apparent spectrum allocations · Traditional

  13. SPITZER OBSERVATIONS OF HOTSPOTS IN RADIO LOBES

    SciTech Connect (OSTI)

    Werner, Michael W.; Murphy, David W.; Livingston, John H.; Gorjian, Varoujan; Jones, Dayton L.; Meier, David L.; Lawrence, Charles R. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2012-11-10T23:59:59.000Z

    We have carried out a systematic search with Spitzer Warm Mission and archival data for infrared emission from the hotspots in radio lobes that have been described by Hardcastle et al. These hotspots have been detected with both radio and X-ray observations, but an observation at an intermediate frequency in the infrared can be critical to distinguish between competing models for particle acceleration and radiation processes in these objects. Between the archival and warm mission data, we report detections of 18 hotspots; the archival data generally include detections at all four IRAC bands, the Warm Mission data only at 3.6 {mu}m. Using a theoretical formalism adopted from Godfrey et al., we fit both archival and warm mission spectral energy distributions (SEDs)-including radio, X-ray, and optical data from Hardcastle as well as the Spitzer data-with a synchrotron self-Compton (SSC) model, in which the X-rays are produced by Compton scattering of the radio frequency photons by the energetic electrons which radiate them. With one exception, an SSC model requires that the magnetic field be less or much less than the equipartition value which minimizes total energy and has comparable amounts of energy in the magnetic field and in the energetic particles. This conclusion agrees with those of comparable recent studies of hotspots, and with the analysis presented by Hardcastle et al. We also show that the infrared data rule out the simplest synchrotron-only models for the SEDs. We briefly discuss the implications of these results and of alternate interpretations of the data.

  14. A Resonant-Mode Model of Pulsar Radio Emission

    E-Print Network [OSTI]

    Matthew D. T. Young

    2003-10-15T23:59:59.000Z

    It is argued that the polar gap and flux tube in the pulsar magnetosphere act as a resonant cavity/waveguide system which is excited by oscillations in the primary beam current and accelerating potential. The modes will be converted, probably scattered, to produce radio beams in the frequency range of those observed.

  15. KUAR: A Flexible Software-Defined Radio Development Platform

    E-Print Network [OSTI]

    Kansas, University of

    towards the possibility of opening certain frequency bands to unlicensed usage. The Federal Communications Commission (FCC) has already commenced work on the concept of unlicensed users "borrowing" spectrum from Communications Magazine Feature Topic on Cognitive Radios for Dynamic Spectrum Access. Advanced Research Projects

  16. Radio Interferometric Geolocation Miklos Maroti

    E-Print Network [OSTI]

    Maróti, Miklós

    Radio Interferometric Geolocation Mikl´os Mar´oti P´eter V¨olgyesi Sebesty´en D´ora Branislav.kusy, akos.ledeczi}@vanderbilt.edu ABSTRACT We present a novel radio interference based sensor local- ization method for wireless sensor networks. The technique relies on a pair of nodes emitting radio waves

  17. Cognitive Radio: Fundamentals and Opportunities

    E-Print Network [OSTI]

    Morelos-Zaragoza, Robert H.

    Cognitive Radio: Fundamentals and Opportunities Robert H. Morelos-Zaragoza Department of Electrical Engineering San Jose State University October 12, 2007 #12;Cognitive Radio - RHMZ - 2007 Slide 2 of 18 Outline 1. Software-defined radio (SDR) a) Black-box approach b) Components and attributes (Mitola) 2

  18. Language Issues for Cognitive Radio

    E-Print Network [OSTI]

    Kokar, Mieczyslaw M.

    INVITED P A P E R Language Issues for Cognitive Radio Computer languages that may be useful for expressing cognitive radio concepts are identified and evaluated in this tutorial paper. By Mieczyslaw M aspects of formal languages in the context of cognitive radio. A bottom up approach is taken in which

  19. On the connection between gamma and radio radiation spectra in pulsars

    E-Print Network [OSTI]

    V. M. Kontorovich; A. B. Flanchik

    2007-12-29T23:59:59.000Z

    The model of pulsar radio emission is discussed in which a coherent radio emis-sion is excited in a vacuum gap above polar cap of neutron star. Pulsar X and gamma radiation are considered as the result of low-frequency radio emission inverse Comp-ton scattering on ultra relativistic electrons accelerated in the gap. The influence of the pulsar magnetic field on Compton scattering is taken into account. The relation of radio and gamma radiation spectra has been found in the framework of the model.

  20. Width of Radio-Loud and Radio-Quiet CMEs

    E-Print Network [OSTI]

    G. Michalek; N. Gopalswamy; H. Xie

    2007-10-24T23:59:59.000Z

    In the present paper we report on the difference in angular sizes between radio-loud and radio-quiet CMEs. For this purpose we compiled these two samples of events using Wind/WAVES and SOHO/LASCO observations obtained during 1996-2005. It is shown that the radio-loud CMEs are almost two times wider than the radio-quiet CMEs (considering expanding parts of CMEs). Furthermore we show that the radio-quiet CMEs have a narrow expanding bright part with a large extended diffusive structure. These results were obtained by measuring the CME widths in three different ways.

  1. Radio Bubbles in Clusters

    E-Print Network [OSTI]

    R. J. H. Dunn; A. C. Fabian; G. B. Taylor

    2005-10-06T23:59:59.000Z

    We extend our earlier work on cluster cores with distinct radio bubbles, adding more active bubbles, i.e. those with Ghz radio emission, to our sample, and also investigating ``ghost bubbles,'' i.e. those without GHz radio emission. We have determined k, which is the ratio of the total particle energy to that of the electrons radiating between 10 MHz and 10 GHz. Constraints on the ages of the active bubbles confirm that the ratio of the energy factor, k, to the volume filling factor, f lies within the range 1 < k/f < 1000. In the assumption that there is pressure equilibrium between the radio-emitting plasma and the surrounding thermal X-ray gas, none of the radio lobes has equipartition between the relativistic particles and the magnetic field. A Monte-Carlo simulation of the data led to the conclusion that there are not enough bubbles present in the current sample to be able to determine the shape of the population. An analysis of the ghost bubbles in our sample showed that on the whole they have higher upper limits on k/f than the active bubbles, especially when compared to those in the same cluster. A study of the Brightest 55 cluster sample shows that 17, possibly 20, clusters required some form of heating as they have a short central cooling time, t_cool < 3 Gyr, and a large central temperature drop, T_centre/T_outer< 1/2. Of these between 12 (70 per cent) and 15 (75 per cent), contain bubbles. This indicates that the duty cycle of bubbles is large in such clusters and that they can play a major role in the heating process.

  2. DIFFUSE RADIO EMISSION IN ABELL 754

    SciTech Connect (OSTI)

    Kale, Ruta; Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India)], E-mail: ruta@rri.res.in, E-mail: dwaraka@rri.res.in

    2009-07-10T23:59:59.000Z

    We present a low-frequency study of the diffuse radio emission in the galaxy cluster A754. We present a new 150 MHz image of the galaxy cluster A754 made with the Giant Metrewave Radio Telescope and discuss the detection of four diffuse features. We compare the 150 MHz image with the images at 74, 330, and 1363 MHz; one new diffuse feature is detected. The flux density upper limits at 330 and 1363 MHz imply a synchrotron spectral index, {alpha}>2 (S {proportional_to} {nu}{sup -{alpha}}), for the new feature. The 'west relic' detected at 74 MHz is not detected at 150 MHz and is thus consistent with its nondetection at 1363 MHz and 330 MHz. Integrated spectra of all the diffuse features are presented. The fourth diffuse feature is located along the proposed merger axis in A754 and 0.7 Mpc away from the peak of X-ray emission; we refer to it as a relic. We have made use of the framework of the adiabatic compression model to obtain spectra. We show that the spectrum of the fourth diffuse feature is consistent with that of a cocoon of a radio galaxy lurking for about 9 x 10{sup 7} yr; no shock compression is required. The other three diffuse emission have spectra steeper than 1.5 and could be cocoons lurking for longer time. We discuss other possibilities such as shocks and turbulent reacceleration being responsible for the diffuse emission in A754.

  3. The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

    E-Print Network [OSTI]

    Perucho, Manel

    2015-01-01T23:59:59.000Z

    Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of helical radio-jets do not correspond to observational artifacts. This conclusion was reached by studying a number of VLBI observations of the radio jet in the quasar S5~0836+710 at different frequencies and epochs. The ridge-line of the emission in the jet coincides at all frequencies within the errors. Moreover, small differences between the ridge-lines as observed at different epochs reveal wave-like motion transversal to the jet propagation axis. I also discuss similar results, albeit with different interpretations, obta...

  4. Short range radio locator system

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1996-01-01T23:59:59.000Z

    A radio location system comprises a wireless transmitter that outputs two megahertz period bursts of two gigahertz radar carrier signals. A receiver system determines the position of the transmitter by the relative arrival of the radar bursts at several component receivers set up to have a favorable geometry and each one having a known location. One receiver provides a synchronizing gating pulse to itself and all the other receivers to sample the ether for the radar pulse. The rate of the synchronizing gating pulse is slightly offset from the rate of the radar bursts themselves, so that each sample collects one finely-detailed piece of information about the time-of-flight of the radar pulse to each receiver each pulse period. Thousands of sequential pulse periods provide corresponding thousand of pieces of information about the time-of-flight of the radar pulse to each receiver, in expanded, not real time. Therefore the signal processing can be done with relatively low-frequency, inexpensive components. A conventional microcomputer is then used to find the position of the transmitter by geometric triangulation based on the relative time-of-flight information.

  5. Radio and Collective Identity in the 2006 Oaxacan Uprising

    E-Print Network [OSTI]

    Rogers, Jennifer B.

    2011-01-01T23:59:59.000Z

    4): Buckley, Steve. 2000. “Radio’s New Horizons: DemocracyDiego. 2007. “Community Radio Stations Under Fire. ” InterWhat is Community Radio? A Resource Guide. Johannesburg:

  6. Surface Plasma Arc by Radio-Frequency Control Study (SPARCS)

    SciTech Connect (OSTI)

    Ruzic, David N. [University of Illinois at Urbana-Champaign, IL (United States)

    2013-04-29T23:59:59.000Z

    This paper is to summarize the work carried out between April 2012 and April 2013 for development of an experimental device to simulate interactions of o#11;-normal detrimental events in a tokamak and ICRF antenna. The work was mainly focused on development of a pulsed plasma source using theta pinch and coaxial plasma gun. This device, once completed, will have a possible application as a test stand for high voltage breakdown of an ICRF antenna in extreme events in a tokamak such as edge-localized modes or disruption. Currently, DEVeX does not produce plasma with high temperature enough to requirement for an ELM simulator. However, theta pinch is a good way to produce high temperature ions. The unique characteristic of plasma heating by a theta pinch is advantageous for an ELM simulator due to its effective ion heating. The objective of the proposed work, therefore, is to build a test facility using the existing theta pinch facility in addition to a coaxial plasma gun. It is expected to produce a similar pulsed-plasma heat load to the extreme events in tokamaks and to be applied for studying interactions of hot plasma and ICRF antennas.

  7. The modification of a radio frequency Cockcroft Walton generator

    E-Print Network [OSTI]

    Holt, Joseph Marion

    1954-01-01T23:59:59.000Z

    iepedanee of the line Ee ia /ja$C', linea the line ia open at the Nth loop~ ZM ia of~ by p, ) 28'4 ~(Alf) ' ' & &2 ~ ~ (6I N (~y) g bC ~ (6) 5N solviag %his emyrlsmfea ter aha ratio ( ? } @islay ( + ) ~ FF0% PifQ$% (2) y ib San bo assn tha, The en...

  8. Switchable and Tunable Ferroelectric Thin Film Radio Frequency

    E-Print Network [OSTI]

    Sarabandi, Kamal

    Beach, Terre Briggs, Timothy Brock, Russ Clifford, Phil Collica, Ning Gulari, Robert Hower, James Kulman

  9. Radio frequency sheath formation and excitation around a stepped electrode

    SciTech Connect (OSTI)

    Barnat, E.V.; Hebner, G.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1423 (United States)

    2005-03-15T23:59:59.000Z

    Plasma and sheath structure around a rf excited stepped electrode is investigated. Laser-induced fluorescence dip spectroscopy is used to spatially resolve sheath fields in an argon discharge while optical emission and laser-induced fluorescence are used to measure the spatial structure of the surrounding discharge for various discharge conditions and step-junction configurations. The presence of the step perturbs the spatial structure of the fields around the step as well as the excitation in the region above the step.

  10. Regenerative processes in a radio-frequency Josephson interferometer

    SciTech Connect (OSTI)

    Gusev, A.V.; Rudenko, V.N.

    1985-01-01T23:59:59.000Z

    Phase modulation of rf oscillations in a Josephson interferometer with hysteresis is described theoretically outside the plateau in the voltage-current characteristic. A generalized phenomenological model is developed for the magnetic flux quantum jumps in interferometers which treats the phase change produced by external perturbations and fluctuations. The forced oscillations become unstable when the coupling between the interferometer loop and the pumping channel reaches a certain value. The application of this instability to maximizing the sensitivity of quantum rf interferometers (so that the sensitivity is limited only by the constraints imposed by fluctuations in the Josephson contact) is discussed.

  11. Narrowband high temperature superconducting receiver for low frequency radio waves

    DOE Patents [OSTI]

    Reagor, David W. (Los Alamos, NM)

    2001-01-01T23:59:59.000Z

    An underground communicating device has a low-noise SQUID using high temperature superconductor components connected to detect a modulated external magnetic flux for outputting a voltage signal spectrum that is related to the varying magnetic flux. A narrow bandwidth filter may be used to select a portion of the voltage signal spectrum that is relatively free of power line noise to output a relatively low noise output signal when operating in a portion of the electromagnetic spectra where such power line noise exists. A demodulator outputs a communication signal, which may be an FM signal, indicative of a modulation on the modulated external magnetic flux.

  12. Grain Growth in Niobium for Superconducting Radio Frequency Cavities

    E-Print Network [OSTI]

    Vernon, Joshua A.

    2009-06-09T23:59:59.000Z

    .......................................................................................................9 3 Polishing Pads and Additives...............................................................................11 1 CHAPTER I INTRODUCTION All metals exhibit different behaviors according to their natural structure, chemical composition.... These scratches should not be seen at 40X magnification. Table 3 lists the pads and additives used in order to achieve such a finish. Table 3. Polishing Pads and Additives. Step Pad Additive Load (lb./specimen) Base Speed (rpm)/Direction Time (min) 1...

  13. FAILURE DATA ANALYSIS OF THE SUPERHILAC RADIO FREQUENCY SUBSYSTEM

    E-Print Network [OSTI]

    Chang, Mark K.

    2012-01-01T23:59:59.000Z

    Applications to Failure Data Analysis," in RELIABILITY ANDLBL-8631 FAILURE DATA ANALYSIS OF THE SUPERHILAC RADIOinterest in our failure data analysis. If the failure rate

  14. Radio frequency wave experiments on the MST reversed field pinch

    SciTech Connect (OSTI)

    Forest, C.B.; Chattopadhyay, P.K.; Nornberg, M.D.; Prager, S.C.; Thomas, M.A. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.; Uchimoto, E. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Smirnov, A.P. [Moscow State Univ. (Russian Federation); Harvey, R.W. [CompX, Del Mar, CA (United States); Ram, A.K. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

    1999-04-01T23:59:59.000Z

    Experiments, simulations, and theory all indicate that the magnetic fluctuations responsible for the poor confinement in the reversed field pinch (RFP) can be controlled by altering the radial profile of the current density. The magnetic fluctuations in the RFP are due to resistive MHD instabilities caused by current profile peaking; thus confinement in the RFP is ultimately the result of a misalignment between inductively driven current profiles and the stable current profiles characteristic of the Taylor state. If a technique such as rf current drive can be developed to non-inductively sustain a Taylor state (a current profile linearly stable to all tearing modes), the confinement of the RFP and its potential as a reactor concept are likely to increase. Whether there is a self-consistent path from poor confinement to greatly improved confinement through current profile modification is an issue for future experiments to address if and only if near term experiments can demonstrate: (1) coupling to and the propagation of rf waves in RFP plasmas, (2) efficient current drive, and (3) control of the power deposition which will make it possible to control the current profile. In this paper, modeling results and experimental plans are presented for two rf experiments which have the potential of satisfying these three goals: high-n{sub {parallel}} lower hybrid (LH) waves and electron Bernstein waves (EBWs).

  15. Radio frequency circuits for wireless receiver front-ends

    E-Print Network [OSTI]

    Xin, Chunyu

    2005-11-01T23:59:59.000Z

    . . . . . . . . 69 2. Implementation of the Down-Conversion Mixer . . . . 69 3. Layout Considerations and Simulation Results . . . . 74 4. Experimental Results of the Mixer Within the Receiver 77 IV BLUETOOTH/WI-FI DUAL-STANDARD RECEIVER RF FRONT...-END : : : : : : : : : : : : : : : : : : : : : : : : : : : : 80 A. Direct Conversion Bluetooth/Wi-Fi Dual-Standard Receiver 81 B. RF Front-End Design Considerations . . . . . . . . . . . . 83 C. Circuits Implementations . . . . . . . . . . . . . . . . . . . 86 1. LNA Implementation...

  16. Fabrication of chip-scale radio frequency inductors

    E-Print Network [OSTI]

    Nation, Joshua C. (Joshua Caleb)

    2014-01-01T23:59:59.000Z

    The purpose of this research was to learn the relationship between force and deformation in forming of micro-scale inductor coils. This was accomplished by applying large-deflection beam bending to the case of planar wire ...

  17. RFQ (radio-frequency quadrupole) accelerator tuning system

    DOE Patents [OSTI]

    Bolie, V.W.

    1988-04-12T23:59:59.000Z

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in responsive to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. 3 figs., 2 tabs.

  18. Radio-frequency quadrupole resonator for linear accelerator

    DOE Patents [OSTI]

    Moretti, A.

    1982-10-19T23:59:59.000Z

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  19. Radio Frequency & Microwave Energy for the Petro Chemical Industry

    E-Print Network [OSTI]

    Raburn, R.

    Electro-Magnetic Energy has finally made its way into the Petro-Chemical market twenty-five years after market acceptance in the Food Processing Industry. Major factors influencing this change are tighter environmental regulations, price competition...

  20. RADIO FREQUENCY PHASE IN THE FEL SECTION OF A TBA

    E-Print Network [OSTI]

    Kuenning, R.W.

    2008-01-01T23:59:59.000Z

    and A. M. Sessler. "A Steady-State FEL: Particle Dynamicsin the FEL Portion of a Two-Beam Accelerator," Proc. of 7thand Amplitude Studies of an FEL: Steady State. lD. Resonant

  1. A space-based radio frequency transient event classifier

    SciTech Connect (OSTI)

    Moore, K.R.; Blain, C.P.; Caffrey, M.P.; Franz, R.C.; Henneke, K.M.; Jones, R.G.

    1998-03-01T23:59:59.000Z

    The Department of Energy is currently investigating economical and reliable techniques for space-based nuclear weapon treaty verification. Nuclear weapon detonations produce RF transients that are signatures of illegal nuclear weapons tests. However, there are many other sources of RF signals, both natural and man-made. Direct digitization of RF signals requires rates of 300 MSamples per second and produces 10{sup 13} samples per day of data to analyze. it is impractical to store and downlink all digitized RF data from such a satellite without a prohibitively expensive increase in the number and capacities of ground stations. Reliable and robust data processing and information extraction must be performed onboard the spacecraft in order to reduce downlinked data to a reasonable volume. The FORTE (Fast On-Orbit Recording of Transient Events) satellite records RF transients in space. These transients will be classified onboard the spacecraft with an Event Classifier specialized hardware that performs signal preprocessing and neural network classification. The authors describe the Event Classifier requirements, scientific constraints, design and implementation.

  2. Synthesis of silicon nitride particles in pulsed radio frequency plasmas

    SciTech Connect (OSTI)

    Buss, R.J. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0367 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0367 (United States); Babu, S.V. [Department of Chemical Engineering, Clarkson University, Potsdam, New York 13699-5705 (United States)] [Department of Chemical Engineering, Clarkson University, Potsdam, New York 13699-5705 (United States)

    1996-03-01T23:59:59.000Z

    Silicon nitride (hydrogenated) particles are synthesized using a pulsed 13.56 MHz glow discharge. The plasma is modulated with a square-wave on/off cycle of varying period to study the growth kinetics. {ital In} {ital situ} laser light scattering and {ital ex} {ital situ} particle analysis are used to study the nucleation and growth. For SiH{sub 4}/Ar and SiH{sub 4}/NH{sub 3} plasmas, an initial very rapid growth phase is followed by slower growth, approaching the rate of thin film deposition on adjacent flat surfaces. The average particle size can be controlled in the 10{endash}100 nm range by adjusting the plasma-on time. The size dispersion of the particles is large and is consistent with a process of continuous nucleation during the plasma-on period. The large polydispersity is also reported for silicon particles from silane and differs from that reported in other laboratories. The silicon nitride particle morphology is compared to that of silicon and silicon carbide particles generated by the same technique. Whereas Si particles appear as rough clusters of smaller subunits, the SiC particles are smooth spheres, and the Si{sub 3}N{sub 4} particles are smooth but nonspherical. Postplasma oxidation kinetics of the particles are studied with Fourier transform infrared spectra and are consistent with a hydrolysis mechanism proposed in earlier work with continuous plasmas. Heat treatment of the powder in an ammonia atmosphere results in the elimination of hydrogen, rendering the silicon nitride resistant to atmospheric oxidation. {copyright} {ital 1996 American Vacuum Society}

  3. Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel Consumption,

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23, 2014, an OHASeptember 2010In addition to 1 |D IMEASUREMENT SENSITIVEWins

  4. Radio Frequency Engineering, MDE, Accelerator Operations and Technology,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection Radiation Protection Regulations: TheCompetition » RadiatorWinsAOT:

  5. Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment3311,Official File UnitedToOn4.docThe4 Conference,EvolutionAdvanced

  6. Microwave and Radio Frequency Workshop | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy ChinaofSchaeferApril 1,(EAC)TABLE OF CONTENTS 1of:Microsoft WordREMARKSMicrosoft Word

  7. Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighand Retrievals from aRodMIT-Harvard CenterHeating" Inventors..--..

  8. Advanced Radio Frequency-Based Sensors for Monitoring Diesel Particulate

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: The Future of1 AAcceleratedDepartment ofDepartment ofMachines

  9. Study of Calibration of Solar Radio Spectrometers and the quiet-Sun Radio Emission

    E-Print Network [OSTI]

    Tan, Chengming; Tan, Baolin; Fu, Qijun; Liu, Yuying; Xu, Guirong

    2015-01-01T23:59:59.000Z

    This work presents a systematic investigation of the influence of weather conditions on the calibration errors by using Gaussian fitness, least chi-square linear fitness and wavelet transform to analyze the calibration coefficients from observations of the Chinese Solar Broadband Radio Spectrometers (at frequency bands of 1.0-2.0 GHz, 2.6-3.8 GHz, and 5.2-7.6 GHz) during 1997-2007. We found that calibration coefficients are influenced by the local air temperature. Considering the temperature correction, the calibration error will reduce by about $10\\%-20\\%$ at 2800 MHz. Based on the above investigation and the calibration corrections, we further study the radio emission of the quiet-Sun by using an appropriate hybrid model of the quiet-Sun atmosphere. The results indicate that the numerical flux of the hybrid model is much closer to the observation flux than that of other ones.

  10. Chameleonic Radio Technical Memo No. 3

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Chameleonic Radio Technical Memo No. 3 Implementation Status of the SCA Based FM Radio P. Balister Institute & State University Blacksburg, VA 24061 #12;Implementation Status of the SCA Based FM Radio Philip description of the FM Radio architecture planned for the SCA radio and provides information about the current

  11. Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems

    E-Print Network [OSTI]

    Dong, Liang

    Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems Liang Dong on the performance of wireless communication systems, such that the prediction of the changing channel behaviors-frequency prediction scheme has superior performance over conducting the channel predic- tion on a single frequency. I

  12. Toward cognitive radio resource management based on multi-agent systems for improvement of

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Communications Commission (FCC) has shown that some frequency bands are overloaded at the rush hours. However spectrum bands while causing no interference to incumbent communications. In this paper, we propose a new, most available radio frequencies have already been allocated. A study carried out by the Federal

  13. RADIO DETECTION OF THE FERMI-LAT BLIND SEARCH MILLISECOND PULSAR J1311-3430

    SciTech Connect (OSTI)

    Ray, P. S.; Wood, K. S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903 (United States); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, I-40129 Bologna (Italy); Cognard, I. [Laboratoire de Physique et Chimie de l'Environnement, LPCE UMR 6115 CNRS, F-45071 Orleans Cedex 02 (France); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bhattacharyya, B. [Inter-University Centre for Astronomy and Astrophysics, Pune 411 007 (India); Roy, J. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India); Romani, R. W.; Kerr, M. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ferrara, E. C. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillemot, L.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Johnston, S.; Keith, M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping NSW 1710 (Australia); Pletsch, H. J. [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, D-30167 Hannover (Germany); Saz Parkinson, P. M., E-mail: Paul.Ray@nrl.navy.mil [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

    2013-01-20T23:59:59.000Z

    We report the detection of radio emission from PSR J1311-3430, the first millisecond pulsar (MSP) discovered in a blind search of Fermi Large Area Telescope (LAT) gamma-ray data. We detected radio pulsations at 2 GHz, visible for <10% of {approx}4.5 hr of observations using the Green Bank Telescope (GBT). Observations at 5 GHz with the GBT and at several lower frequencies with Parkes, Nancay, and the Giant Metrewave Radio Telescope resulted in non-detections. We also report the faint detection of a steep spectrum continuum radio source (0.1 mJy at 5 GHz) in interferometric imaging observations with the Jansky Very Large Array. These detections demonstrate that PSR J1311-3430 is not radio quiet and provide additional evidence that radio-quiet MSPs are rare. The radio dispersion measure of 37.8 pc cm{sup -3} provides a distance estimate of 1.4 kpc for the system, yielding a gamma-ray efficiency of 30%, typical of LAT-detected MSPs. We see apparent excess delay in the radio pulses as the pulsar appears from eclipse and we speculate on possible mechanisms for the non-detections of the pulse at other orbital phases and observing frequencies.

  14. Hop Reservation Multiple Access (HRMA) for Multichannel Packet Radio Networks \\Lambda Zhenyu Tang and J. J. GarciaLunaAceves

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Hop Reservation Multiple Access (HRMA) for Multichannel Packet Radio Networks \\Lambda Zhenyu Tang Hop Reservation Mul­ tiple Access (HRMA) for packet­radio networks is introduced, specified and analyzed. HRMA is based on very­slow frequency­ hopping spread spectrum (FHSS) and takes advantage

  15. 2010 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency

    E-Print Network [OSTI]

    Jain, Raj

    , Magnetic Ink Character Recognition (MICR) on Bank Checks #12;24-4 ©2010 Raj JainCSE574s: Powered by incoming RF. Smaller, cheaper, long-life. Approx range 5m. Active Tags: Battery powered. Can power. Battery for logic. Range like passive. Reliability like active. #12;24-8 ©2010 Raj JainCSE574s

  16. 2006 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency

    E-Print Network [OSTI]

    Jain, Raj

    , Magnetic Ink Character Recognition (MICR) on Bank Checks #12;18-4 ©2006 Raj JainCSE574s by incoming RF. Smaller, cheaper, long-life. Approx range 5m. " Active Tags: Battery powered. Can be read 100 power. Battery for logic. Range like passive. Reliability like active. #12;18-7 ©2006 Raj JainCSE574s

  17. GNU Radio & USRPGNU Radio & USRP File transfer through WirelessFile transfer through Wireless

    E-Print Network [OSTI]

    Yu, Chansu

    1 GNU Radio & USRPGNU Radio & USRP File transfer through WirelessFile transfer through WirelessSachin Hirve April 30, 2008April 30, 2008 Contents:Contents: What is Software Radio?What is Software Radio? USRPUSRP ­­ MultiMulti--functional hardwarefunctional hardware GNU RadioGNU Radio Previous Work

  18. Elements of Radio Waves

    E-Print Network [OSTI]

    Frank G. Borg; Ismo Hakala; Jukka Määttälä

    2007-12-24T23:59:59.000Z

    We present a summary of the basic properties of the radio wave generation, propagation and reception, with a special attention to the gigahertz bandwidth region which is of interest for wireless sensor networks. We also present some measurement results which use the so-called RSSI indicator in order to track how the field strength varies with position and distance of the transceivers. We hope the paper may be useful to anyone who looks for a quick review of the fundamentals of electromagnetic theory with application to antennas.

  19. Multiphase turbulent interstellar medium: some recent results from radio astronomy

    E-Print Network [OSTI]

    Roy, Nirupam

    2015-01-01T23:59:59.000Z

    The radio frequency 1.4 GHz transition of the atomic hydrogen is one of the important tracers of the diffuse neutral interstellar medium. Radio astronomical observations of this transition, using either a single dish telescope or an array interferometer, reveal different properties of the interstellar medium. Such observations are particularly useful to study the multiphase nature and turbulence in the interstellar gas. Observations with multiple radio telescopes have recently been used to study these two closely related aspects in greater detail. Using various observational techniques, the density and the velocity fluctuations in the Galactic interstellar medium was found to have a Kolmogorov-like power law power spectra. The observed power law scaling of the turbulent velocity dispersion with the length scale can be used to derive the true temperature distribution of the medium. Observations from a large ongoing atomic hydrogen absorption line survey have also been used to study the distribution of gas at d...

  20. Cluster Mergers and Diffuse Radio Emission in Abell 2256 and Abell 754

    E-Print Network [OSTI]

    T. E. Clarke; T. A. Ensslin

    2001-06-07T23:59:59.000Z

    We present deep VLA observations of the galaxy clusters Abell 2256 and Abell 754, both of which appear to be in the violent stage of major cluster merger events. The complex nature of Abell 2256 is revealed through radio images which, in addition to the head-tail galaxies, show two extended, irregular, and sharp-edged regions of diffuse radio emission at the cluster periphery (so called radio relics), and a large-scale diffuse radio halo located in the central regions of the cluster. Polarimetry of the A2256 cluster relics reveals large-scale ordered magnetic fields which appear to trace the bright filaments in the relics. The polarization fraction across the relics ranges from 20% - 40% with the majority of the relics polarized above the 30% level. At the sensitivity of our current observations we place an upper limit of 20% on the polarization of the radio halo. Low frequency VLA observations of Abell 754 reveal extended, diffuse radio (halo) emission in the cluster core region as well as steep spectrum emission in the cluster periphery. The location, morphology, and spectral index of the peripheral emission are consistent with the properties of radio relics. The X-ray evidence of the ongoing mergers in both clusters, together with the polarization properties of A2256's radio relics supports recent suggestions of a merger-induced origin of the relic emission. Deciphering the complex radio properties of these clusters may thus provide the key to understanding the dynamical history of the systems.

  1. Radio Remote Sensing of the Corona and the Solar Wind

    E-Print Network [OSTI]

    Steven R. Spangler; Catherine A. Whiting

    2008-09-26T23:59:59.000Z

    Modern radio telescopes are extremely sensitive to plasma on the line of sight from a radio source to the antenna. Plasmas in the corona and solar wind produce measurable changes in the radio wave amplitude and phase, and the phase difference between wave fields of opposite circular polarization. Such measurements can be made of radio waves from spacecraft transmitters and extragalactic radio sources, using radio telescopes and spacecraft tracking antennas. Data have been taken at frequencies from about 80 MHz to 8000 MHz. Lower frequencies probe plasma at greater heliocentric distances. Analysis of these data yields information on the plasma density, density fluctuations, and plasma flow speeds in the corona and solar wind, and on the magnetic field in the solar corona. This paper will concentrate on the information that can be obtained from measurements of Faraday rotation through the corona and inner solar wind. The magnitude of Faraday rotation is proportional to the line of sight integral of the plasma density and the line-of-sight component of the magnetic field. Faraday rotation provides an almost unique means of estimating the magnetic field in this part of space. This technique has contributed to measurement of the large scale coronal magnetic field, the properties of electromagnetic turbulence in the corona, possible detection of electrical currents in the corona, and probing of the internal structure of coronal mass ejections (CMEs). This paper concentrates on the search for small-scale coronal turbulence and remote sensing of the structure of CMEs. Future investigations with the Expanded Very Large Array (EVLA) or Murchison Widefield Array (MWA) could provide unique observational input on the astrophysics of CMEs.

  2. On the origin of radio emission in radio quiet quasars

    E-Print Network [OSTI]

    Ari Laor; Ehud Behar

    2008-08-05T23:59:59.000Z

    The radio emission in radio loud quasars originates in a jet carrying relativistic electrons. In radio quiet quasars (RQQs) the relative radio emission is ~10^3 times weaker, and its origin is not established yet. We show here that there is a strong correlation between the radio luminosity (L_R) and X-ray luminosity (L_X) with L_R~10^-5L_X, for the radio quiet Palomar-Green (PG) quasar sample. The sample is optically selected, with nearly complete radio and X-ray detections, and thus this correlation cannot be due to direct selection biases. The PG quasars lie on an extension of a similar correlation noted by Panessa et al., for a small sample of nearby low luminosity type 1 AGN. A remarkably similar correlation, known as the Guedel-Benz relation, where L_R/L_X~10^-5, holds for coronally active stars. The Guedel-Benz relation, together with correlated stellar X-ray and radio variability, implies that the coronae are magnetically heated. We therefore raise the possibility that AGN coronae are also magnetically heated, and that the radio emission in RQQ also originates in coronal activity. If correct, then RQQ should generally display compact flat cores at a few GHz due to synchrotron self-absorption, while at a few hundred GHz we should be able to see directly the X-ray emitting corona, and relatively rapid and large amplitude variability, correlated with the X-ray variability, is likely to be seen. We also discuss possible evidence that the radio and X-ray emission in ultra luminous X-ray sources and Galactic black holes may be of coronal origin as well.

  3. A procedure for oscillatory parameter identification

    SciTech Connect (OSTI)

    Trudnowski, D.J.; Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Hauer, J.F. [Bonneville Power Administration, Portland, OR (United States)

    1994-02-01T23:59:59.000Z

    A procedure is proposed where a power system is excited with a low-level pseduo-random probing signal and the frequency, damping, magnitude, and shape of oscillatory modes are identified using spectral density estimation and frequency-domain transfer-function identification. Attention is focussed on identifying system modes in the presence of noise. Two examples cases are studied: identification of electromechanical oscillation modes in a 16-machine power system; and turbine-generator shaft modes of a 3-machine power plant feeding a series-compensated 500-kV network.

  4. Resonant circuit which provides dual-frequency excitation for rapid cycling of an electromagnet

    DOE Patents [OSTI]

    Praeg, W.F.

    1982-03-09T23:59:59.000Z

    Disclosed is a novel ring-magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the sinusoidal guide field of the ring magnet during particle acceleration. The control circuit generates sinusoidal excitation currents of different frequencies in the half waves. During radio-frequency acceleration of the synchrotron, the control circuit operates with a lower frequency sine wave and, thereafter, the electromagnets are reset with a higher-frequency half sine wave.

  5. ISM band to U-NII band frequency transverter and method of frequency transversion

    DOE Patents [OSTI]

    Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

    2006-04-04T23:59:59.000Z

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  6. ISM band to U-NII band frequency transverter and method of frequency transversion

    SciTech Connect (OSTI)

    Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

    2006-09-12T23:59:59.000Z

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  7. Radio Emission from the Milky Way

    E-Print Network [OSTI]

    Bryan Gaensler

    2004-01-13T23:59:59.000Z

    In the last 5-10 years, wide-field imaging capabilities and effective mosaicing algorithms have made possible a variety of ambitious interferometric surveys of the Galaxy, resulting in images of unprecedented sensitivity and resolution. Here I discuss some of the highlights from these new surveys. Amongst the new results are the identification of many new supernova remnants in confused regions, spectacular low frequency images of the inner Galaxy with the VLA, and some remarkable new insights into the structure of the Galactic magnetic field from linear polarization.

  8. A Radio SETI Campaign for microsec-sec Periodic Signals

    E-Print Network [OSTI]

    Harp, G R; Astorga, Alfredo; Arbunich, Jack; Hightower, Kristin; Meitzner, Seth; Barott, W C; Nolan, Michael C; Messerschmitt, D G; Vakoch, Douglas A; Shostak, Seth; Tarter, J C

    2015-01-01T23:59:59.000Z

    We report a novel radio autocorrelation (AC) search for extraterrestrial intelligence (SETI). For selected frequencies across the terrestrial microwave window (1-10 GHz) observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 1 kHz, which are capable of carrying substantial messages with symbol-rates from 10-10e6 Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux greater than 1 Jy (quasars, pulsars, supernova remnants and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial, repetitive, phase or frequency modulation. The rest of the targets were mostly toward exoplanet stars and similarly interesting targets from the standpoint of SETI. This campaign rules out several previously untested hypotheses relating to the number of artificially modulated "natural" sources. Since we are using a phase sensitive detector, these obser...

  9. High precision difference astrometry applied to the triplet of S5 radio sources B1803+784/Q1928+738/B2007+777

    E-Print Network [OSTI]

    E. Ros; J. M. Marcaide; J. C. Guirado; M. I. Ratner; I. I. Shapiro; T. P. Krichbaum; A. Witzel; R. A. Preston

    1999-07-05T23:59:59.000Z

    We determined the separations of the radio sources in the triangle formed by the BL Lac objects 1803+784 and 2007+777, and the QSO 1928+738 from intercontinental interferometric observations carried out in November 1991 at the frequencies of 2.3 and 8.4 GHz simultaneously. We successfully connected differenced phase delays over 7^o on the sky at 8.4 GHz at an epoch of maximum solar activity. The effects of the ionosphere on these VLBI data were mostly removed by estimates of the total electron content from observations of GPS satellites. The comparison of the estimated separation of QSO 1928+738 and BL 2007+777 with previous such estimates obtained from data at different epochs leads us to a particular alignment of the maps of QSO 1928+738 at different epochs relative to those of BL 2007+777, although with significant uncertainty. For this alignment, the jet components of QSO 1928+738 show a mean proper motion of 0.32+/-0.10 mas/yr and also suggest an identification for the position of the core of this radio source.

  10. Storm in a "Teacup": a radio-quiet quasar with ~10kpc radio-emitting bubbles and extreme gas kinematics

    E-Print Network [OSTI]

    Harrison, C M; Alexander, D M; Bauer, F E; Edge, A C; Hogan, M T; Mullaney, J R; Swinbank, A M

    2014-01-01T23:59:59.000Z

    We present multi-frequency (1-8 GHz) VLA data, combined with VIMOS IFU data and HST imaging, of a z=0.085 radio-quiet type 2 quasar (with L(1.4GHz)~5e23 W/Hz and L(AGN)~2e45 erg/s). Due to the morphology of its emission-line region, the target (J1430+1339) has been referred to as the Teacup AGN in the literature. We identify "bubbles" of radio emission that are extended ~10-12 kpc to both the east and west of the nucleus. The edge of the brighter eastern bubble is co-spatial with an arc of luminous ionized gas. We also show that the Teacup AGN hosts a compact radio structure, located ~0.8 kpc from the core position, at the base of the eastern bubble. This radio structure is co-spatial with an ionized outflow with an observed velocity of v=-760 km/s. This is likely to correspond to a jet, or possibly a quasar wind, interacting with the interstellar medium at this position. The large-scale radio bubbles appear to be inflated by the central AGN, which indicates that the AGN can also interact with the gas on >~10...

  11. Magnetic Field Geometry of the Broad Line Radio Galaxy 3C111

    E-Print Network [OSTI]

    P. Kharb; D. Gabuzda; W. Alef; E. Preuss; P. Shastri

    2003-01-06T23:59:59.000Z

    Very Long Baseline Polarimetric observations of the Broad Line Radio galaxy 3C111 performed in July and September of 1996 at 8 and 43 GHz reveal rapidly evolving parsec-scale radio structure after a large millimetre outburst. The B-field geometry is not simple. We present a first analysis of possible Faraday and optical depth effects based on a comparison of the polarization images for the two frequencies.

  12. Attenuation of radio signals by the ionosphere of Mars: Theoretical

    E-Print Network [OSTI]

    Withers, Paul

    radio frequency and peak electron density Molina-Cuberos et al. (2002) #12;Power loss equation · Effects solution #12;Power loss at 1, 10, 100, 1000 MHz 1 MHz, 64 km 100 MHz, 29 km 1 GHz, 12 km 10 MHz, 47 km f · Thus P > 1 dB only for f power loss from main ionospheric layer if NXC > 2E10 m-3

  13. Radio Wave 'Messengers' of Periodic Gravitational Radiation and the Problem of Gravitationally Induced Nonlinearity in Electrodynamic Systems

    E-Print Network [OSTI]

    A. B. Balakin; Z. G. Murzakhanov; G. V. Kisun'ko

    2005-11-10T23:59:59.000Z

    We discuss a gravitationally induced nonlinearity in hierarchic systems. We consider the generation of extremely low-frequency radio waves with a frequency of the periodic gravitational radiation; the generation is due to an induced nonlinear self-action of electromagnetic radiation in the vicinity of the gravitational-radiation source. These radio waves are a fundamentally new type of response of an electrodynamic system to gravitational radiation. That is why we here use an unconventional term: radio-wave messengers of periodic gravitational radiation.

  14. ATLBS EXTENDED SOURCE SAMPLE: THE EVOLUTION IN RADIO SOURCE MORPHOLOGY WITH FLUX DENSITY

    SciTech Connect (OSTI)

    Saripalli, L.; Subrahmanyan, R.; Thorat, K.; Ekers, R. D. [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Hunstead, R. W.; Johnston, H. M.; Sadler, E. M., E-mail: lsaripal@rri.res.in [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

    2012-04-01T23:59:59.000Z

    Based on the Australia Telescope Low Brightness Survey (ATLBS) we present a sample of extended radio sources and derive morphological properties of faint radio sources. One hundred nineteen radio galaxies form the ATLBS Extended Source Sample (ATLBS-ESS) consisting of all sources exceeding 30'' in extent and integrated flux densities exceeding 1 mJy. We give structural details along with information on galaxy identifications and source classifications. The ATLBS-ESS, unlike samples with higher flux-density limits, has almost equal fractions of FR-I and FR-II radio galaxies, with a large fraction of the FR-I population exhibiting 3C31-type structures. Significant asymmetry in lobe extents appears to be a common occurrence in the ATLBS-ESS FR-I sources compared with FR-II sources. We present a sample of 22 FR-Is at z > 0.5 with good structural information. The detection of several giant radio sources, with size exceeding 0.7 Mpc, at z > 1 suggests that giant radio sources are not less common at high redshifts. The ESS also includes a sample of 28 restarted radio galaxies. The relative abundance of dying and restarting sources is indicative of a model where radio sources undergo episodic activity in which an active phase is followed by a brief dying phase that terminates with restarting of the central activity; in any massive elliptical a few such activity cycles wherein adjacent events blend may constitute the lifetime of a radio source and such bursts of blended activity cycles may be repeated over the age of the host. The ATLBS-ESS includes a 2 Mpc giant radio galaxy with the lowest surface brightness lobes known to date.

  15. The unusual radio afterglow of the ultra-long gamma-ray burst GRB 130925A

    E-Print Network [OSTI]

    Horesh, Assaf; Perley, Daniel A; Kulkarni, S R; Hallinan, Gregg; Bellm, Eric

    2015-01-01T23:59:59.000Z

    GRB 130925A is one of the recent additions to the growing family of ultra-long GRBs (T90$ \\gtrsim 1000$ s). While the X-ray emission of ultra-long GRBs have been studied extensively in the past, no comprehensive radio dataset has been obtained so far. We report here the early discovery of an unusual radio afterglow associated with the ultra-long GRB 130925A. The radio emission peaks at low-frequencies ($\\sim 7$ GHz) at early times, only $2.2$ days after the burst occurred. More notably, the radio spectrum at frequencies above $10$ GHz exhibits a rather steep cut-off, compared to other long GRB radio afterglows. This cut-off can be explained if the emitting electrons are either mono-energetic or originate from a rather steep, $dN/dE \\propto E^{-4}$, power-law energy distribution. An alternative electron acceleration mechanism may be required to produce such an electron energy distribution. Furthermore, the radio spectrum exhibits a secondary underlying and slowly varying component. This may hint that the radio...

  16. Radio bursts from superconducting strings

    E-Print Network [OSTI]

    Yi-Fu Cai; Eray Sabancilar; Tanmay Vachaspati

    2012-01-30T23:59:59.000Z

    We show that radio bursts from cusps on superconducting strings are linearly polarized, thus, providing a signature that can be used to distinguish them from astrophysical sources. We write the event rate of string-generated radio transients in terms of observational variables, namely, the event duration and flux. Assuming a canonical set of observational parameters, we find that the burst event rate can be quite reasonable, e.g., order ten a year for Grand Unified strings with 100 TeV currents, and a lack of observed radio bursts can potentially place strong constraints on particle physics models.

  17. Blind Identification of MIMO FIR Systems Driven by Quasi-Stationary Sources Using Second Order

    E-Print Network [OSTI]

    Reilly, James P.

    1 Blind Identification of MIMO FIR Systems Driven by Quasi-Stationary Sources Using Second Order This paper discusses a frequency domain method for blind identification of MIMO convolutive channels driven are presented to demonstrate the performance of the new algorithm1 . I. Introduction Blind identification

  18. Peptide identification

    DOE Patents [OSTI]

    Jarman, Kristin H [Richland, WA; Cannon, William R [Richland, WA; Jarman, Kenneth D [Richland, WA; Heredia-Langner, Alejandro [Richland, WA

    2011-07-12T23:59:59.000Z

    Peptides are identified from a list of candidates using collision-induced dissociation tandem mass spectrometry data. A probabilistic model for the occurrence of spectral peaks corresponding to frequently observed partial peptide fragment ions is applied. As part of the identification procedure, a probability score is produced that indicates the likelihood of any given candidate being the correct match. The statistical significance of the score is known without necessarily having reference to the actual identity of the peptide. In one form of the invention, a genetic algorithm is applied to candidate peptides using an objective function that takes into account the number of shifted peaks appearing in the candidate spectrum relative to the test spectrum.

  19. Quark Nova Model for Fast Radio Bursts

    E-Print Network [OSTI]

    Zachary Shand; Amir Ouyed; Nico Koning; Rachid Ouyed

    2015-05-29T23:59:59.000Z

    FRBs are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via $\\beta$-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm$^{-3}$ pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of $\\beta$-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies ($\\sim$ 10$^{41}$ ergs), spectra shapes and provide a theoretical framework for determining distances.

  20. Spectrum Sensing and Reconstruction for Cognitive Radio

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Spectrum Sensing and Reconstruction for Cognitive Radio Amanpreet S Saini, Zhen Hu, Robert Qiu with spectrum sensing and spectrum reconstruction under the umbrella of cognitive radio which is the smart radio to explore and exploit the free spectrum. Spectrum analyzer is used to emulate cognitive radio to do spectrum

  1. Royal Institute of Technology Cognitive Radio

    E-Print Network [OSTI]

    Maguire Jr., Gerald Q.

    Royal Institute of Technology Cognitive Radio Model-Based Competence for Software Radios Joseph Communication Systems Laboratory Royal Institute of Technology Stockholm, Sweden Cognitive Radio Model-Based Competence for Software Radios Joseph Mitola III August 1999 A thesis submitted to the Royal Institute

  2. Cognitive Radio Technology [from THE GUEST EDITORS

    E-Print Network [OSTI]

    Di Benedetto, Maria-Gabriella

    Cognitive Radio Technology [from THE GUEST EDITORS] Maria Gabriella di Benedetto, Yingbo Hua, Thomas Kaiser, and Xiaodong Wang C ognitive radio is an exciting and new way of thinking and researching of cognitive radio. Perhaps the most pressing of them is improved utilization of the electromagnetic radio

  3. Chameleonic Radio Technical Memo No. 17

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Chameleonic Radio Technical Memo No. 17 The Rise of All-Band All- Mode Radio S.W. Ellingson and S Institute & State University #12;The Rise of All-Band All-Mode Radio Steve Ellingson and S.M. Shajedul Hasan is based on network infrastructure. In this approach, disparate radio networks are integrated through

  4. Radio Astronomy Fundamentals I John Simonetti

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Radio Astronomy Fundamentals I John Simonetti Spring 2012 Radio astronomy provides a very different view of the universe than optical astronomy. Radio astronomers and optical astronomers use different terminology to describe their work. Here I present some basic concepts and terms of radio

  5. Chameleonic Radio Technical Memo No. 1

    E-Print Network [OSTI]

    Ellingson, Steven W.

    Chameleonic Radio Technical Memo No. 1 Prototyping a Software Defined Radio Receiver Based on USRP Defined Radio (SDR) is an emerging technology which supports multi- standard, multi-mode and future proof radio designs. There are several SDR software architectures have been developed during the last few

  6. Radio: Borderless and selective On the use codes in radio broadcast

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Radio: Borderless and selective On the use codes in radio broadcast Jacob Thøgersen The universal radio In the beginning of the 21st century, the Internet may be heralded as the great bringer of free invention, the radio. In Denmark, the earliest experiments with radio broadcasting started as private

  7. Axion Stars and Fast Radio Bursts

    E-Print Network [OSTI]

    A. Iwazaki

    2014-10-23T23:59:59.000Z

    We show that fast radio bursts arise from collisions between axion stars and neutron stars. The bursts are emitted in the atmosphere of the neutron stars. The observed frequencies of the bursts are given by the axion mass $m_a$ such as $m_a/2\\pi\\simeq 1.4\\,\\mbox{GHz}\\,\\big(m_a/(6\\times 10^{-6}\\mbox{eV})\\big)$. From the event rate $\\sim 10^{-3}$ per year in a galaxy, we can determine the mass $\\sim 10^{-11}M_{\\odot}$ of the axion stars. Using these values we can explain short durations ( $\\sim $ms ) and amount of radiation energies ( $\\sim 10^{43}$GeV ) of the bursts.

  8. Carrier-frequency synchronization system for improved amplitude modulation and television broadcast reception

    DOE Patents [OSTI]

    Smith, Stephen F.; Moore, James A.

    2003-05-13T23:59:59.000Z

    Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

  9. Synchronizing carrier frequencies of co-channel amplitude-modulated broadcast

    DOE Patents [OSTI]

    Smith, Stephen F. (London, TN); Moore, James A. (Powell, TN)

    2007-05-15T23:59:59.000Z

    Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

  10. Tradeoff between spoofing and jamming a cognitive radio

    E-Print Network [OSTI]

    Peng, Q; Cosman, P C; Milstein, L B

    2009-01-01T23:59:59.000Z

    tradeoff for cognitive radio networks,” IEEE Transactions onemulation attacks in cognitive radio networks,” IEEE Journaldeception for cognitive radio networks,” IEEE Globecom 2009,

  11. RADIO OBSERVATRIO DO ITAPETINGA, ATIBAIA, SP ZONA DE SILNCIO ELTRICO.

    E-Print Network [OSTI]

    RADIO OBSERVATÓRIO DO ITAPETINGA, ATIBAIA, SP ZONA DE SILÊNCIO ELÉTRICO. PROTEÇÃO DO RÁDIO uma Radio Conferência Mundial (World Adminstrative Radio Conference, WARC) patrocinada pela União

  12. A Method for Broadband Full-Duplex MIMO Radio

    E-Print Network [OSTI]

    Hua, Yingbo; Liang, Ping; Ma, Yiming; Cirik, Ali C; Gao, Qian

    2012-01-01T23:59:59.000Z

    canceller for collocated radios,” IEEE Trans. Microwaveusing off-the shelf radios: Feasibility and first results,”Broadband Full-Duplex MIMO Radio Yingbo Hua, Fellow, IEEE,

  13. The Isotropic Radio Background and Annihilating Dark Matter

    SciTech Connect (OSTI)

    Hooper, Dan [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Belikov, Alexander V. [Institut d'Astrophysique (France); Jeltema, Tesla E. [Univ. of California, Santa Cruz, CA (United States); Linden, Tim [Univ. of California, Santa Cruz, CA (United States); Profumo, Stefano [Univ. of California, Santa Cruz, CA (United States); Slatyer, Tracy R. [Princeton Univ., Princeton, NJ (United States)

    2012-11-01T23:59:59.000Z

    Observations by ARCADE-2 and other telescopes sensitive to low frequency radiation have revealed the presence of an isotropic radio background with a hard spectral index. The intensity of this observed background is found to exceed the flux predicted from astrophysical sources by a factor of approximately 5-6. In this article, we consider the possibility that annihilating dark matter particles provide the primary contribution to the observed isotropic radio background through the emission of synchrotron radiation from electron and positron annihilation products. For reasonable estimates of the magnetic fields present in clusters and galaxies, we find that dark matter could potentially account for the observed radio excess, but only if it annihilates mostly to electrons and/or muons, and only if it possesses a mass in the range of approximately 5-50 GeV. For such models, the annihilation cross section required to normalize the synchrotron signal to the observed excess is sigma v ~ (0.4-30) x 10^-26 cm^3/s, similar to the value predicted for a simple thermal relic (sigma v ~ 3 x 10^-26 cm^3/s). We find that in any scenario in which dark matter annihilations are responsible for the observed excess radio emission, a significant fraction of the isotropic gamma ray background observed by Fermi must result from dark matter as well.

  14. MODELING OF GYROSYNCHROTRON RADIO EMISSION PULSATIONS PRODUCED BY MAGNETOHYDRODYNAMIC LOOP OSCILLATIONS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2012-04-01T23:59:59.000Z

    A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

  15. A Combined EIS-NVSS Survey Of Radio Sources (CENSORS) III: Spectroscopic observations

    E-Print Network [OSTI]

    M. H. Brookes; P. N. Best; J. A. Peacock; H. J. A. Rottgering; J. S. Dunlop

    2008-02-08T23:59:59.000Z

    The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4GHz radio survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which is a 3 by 2 square degree field centred on 09 51 36.0, -21 00 00 (J2000). This paper presents the results of spectroscopic observations of 143 of the 150 CENSORS sources. The primary motivation for these observations is to achieve sufficient spectroscopic completeness so that the sample may be used to investigate the evolution of radio sources. The observations result in secure spectroscopic redshifts for 63% of the sample and likely redshifts (based on a single emission line, for example) for a further 8%. Following the identification of the quasars and star-forming galaxies in the CENSORS sample, estimated redshifts are calculated for the remainder of the sample via the K-z relation for radio galaxies. Comparison of the redshift distribution of the CENSORS radio sources to distributions predicted by the various radio luminosity function evolution models of Dunlop & Peacock 1990, results in no good match. This demonstrates that this sample can be used to expand upon previous work in that field.

  16. RADIO SEARCH FOR H{sub 2}CCC TOWARD HD 183143 AS A CANDIDATE FOR A DIFFUSE INTERSTELLAR BAND CARRIER

    SciTech Connect (OSTI)

    Araki, Mitsunori; Yamabe, Hiromichi; Tsukiyama, Koichi [Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku 162-8601, Tokyo (Japan); Takano, Shuro [Nobeyama Radio Observatory and Department of Astronomical Science, The Graduate University for Advanced Studies (Sokendai), 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Kuze, Nobuhiko, E-mail: araki@rs.kagu.tus.ac.jp [Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku 102-8554, Tokyo (Japan)

    2012-07-01T23:59:59.000Z

    To clarify the authenticity of a recently proposed identification of H{sub 2}CCC (linear-C{sub 3}H{sub 2}) as a diffuse interstellar band (DIB) carrier, we searched for the rotational transition of H{sub 2}CCC at a frequency of 103 GHz toward HD 183143 using the 45 m telescope at the Nobeyama Radio Observatory. Although rms noise levels of 32 mK in the antenna temperature were achieved, detection of H{sub 2}CCC was unsuccessful, producing a 3{sigma} upper limit corresponding to a column density of 2.0 Multiplication-Sign 10{sup 13} cm{sup -2}. The upper limit indicates that the contribution of H{sub 2}CCC to the DIB at 5450 Angstrom-Sign is less than 1/25; thus, it is unlikely that the laboratory bands of the B{sup 1} B{sub 1}-X{sup 1} A{sub 1} transition of H{sub 2}CCC and the DIBs at 5450 Angstrom-Sign (and also 4881 Angstrom-Sign ) toward HD 183143 are related.

  17. Cosmological Radio Emission induced by WIMP Dark Matter

    E-Print Network [OSTI]

    N. Fornengo; R. Lineros; M. Regis; M. Taoso

    2012-03-05T23:59:59.000Z

    We present a detailed analysis of the radio synchrotron emission induced by WIMP dark matter annihilations and decays in extragalactic halos. We compute intensity, angular correlation, and source counts and discuss the impact on the expected signals of dark matter clustering, as well as of other astrophysical uncertainties as magnetic fields and spatial diffusion. Bounds on dark matter microscopic properties are then derived, and, depending on the specific set of assumptions, they are competitive with constraints from other indirect dark matter searches. At GHz frequencies, dark matter sources can become a significant fraction of the total number of sources with brightness below the microJansky level. We show that, at this level of fluxes (which are within the reach of the next-generation radio surveys), properties of the faint edge of differential source counts, as well as angular correlation data, can become an important probe for WIMPs.

  18. Some Comments related to AGN Radio Loudness

    E-Print Network [OSTI]

    Ari Laor

    2003-12-24T23:59:59.000Z

    The bimodality of the AGN radio loudness distribution, and the relation of radio loudness and black hole mass were recently disputed. A closer look at the existing data suggests possible resolutions of these disputes, as further described below.

  19. Fast Radio Bursts from Axion Stars

    E-Print Network [OSTI]

    Aiichi Iwazaki

    2015-04-20T23:59:59.000Z

    Axions are one of the most promising candidates of dark matter. The axions have been shown to form miniclusters with masses $\\sim 10^{-12}M_{\\odot}$, some of which condense to form axion stars. We have recently shown a possible origin of fast radio bursts ( FRBs ) by assuming that the axion stars are main component of halos: FRBs arise from the collisions between the axion stars and neutron stars. It is remarkable that the masses of the axion stars obtained by the comparison of the theoretical and observational event rates are coincident with the mass $\\sim 10^{-12}M_{\\odot}$. In this paper, we describe our model of FRBs in detail. We derive the approximate solutions of the axion stars with large radii and constraint their masses for the approximation to be valid. The FRBs are emitted from the atmospheres of neutron stars in the collisions. By calculating the optical depth of the atmospheres, we show that they are transparent for the radiations with the frequency given by the axion mass $m_a$ such as $m_a/2\\pi\\simeq 2.4$GHz$(m_a/10^{-5}\\rm eV)$. Although the radiations are linearly polarized when they are emitted, they are shown to be circularly polarized after they pass magnetospheres of neutron stars. We also show that the frequencies of the FRBs have finite bandwidths owing to the Doppler effect when the neutron stars pass through the axion stars. The presence of the finite bandwidths is a distinctive feature of our model and can be tested observationally. Furthermore, we show that similar FRBs may arise when the axion stars collide with magnetic white dwarfs. The characteristic feature is that the durations of the bursts are of the order of $0.1$second and they are monochromatic contrary to the FRBs observed. We can determine the axion mass by the observating both of the their frequencies and red shifts $z$.

  20. Radio Science, Volume ???, Number , Pages 131, Radio tomography of the ionosphere: Analysis

    E-Print Network [OSTI]

    Garcia, Raphaël

    Radio Science, Volume ???, Number , Pages 1­31, Radio tomography of the ionosphere: Analysis AND CRESPON: 4D IONOSPHERE TOMOGRAPHY After analysing the forward and inverse problems of radio tomography, the development of Faraday rotation measurements on-board satellites opens the way to magnetospheric radio

  1. Final Project Report Modulate of Internet Radio Into FM Using GNU Radio

    E-Print Network [OSTI]

    Yu, Chansu

    Final Project Report Modulate of Internet Radio Into FM Using GNU Radio Department of Electrical-Introduction: Internet radio (also known as Webcasting) is becoming more and more popular. Especially that it covers for people traveling all the time or living away from there home country, internet radio helps them keep

  2. Radio Science, Volume ???, Number , Pages 110, Time Reversal of Electromagnetic Waves and

    E-Print Network [OSTI]

    Paris 7 - Denis Diderot, Université

    electromagnetic pulse at a central frequency of 2.45 GHz in a high-Q cavity. Another antenna records the stronglyRadio Science, Volume ???, Number , Pages 1­10, Time Reversal of Electromagnetic Waves demonstration of time-reversal focusing with electromagnetic waves in a SISO scheme. An antenna transmits a 1 µs

  3. A limit on the ultra-high-energy neutrino flux from lunar observations with the Parkes radio telescope

    E-Print Network [OSTI]

    Bray, J D; Roberts, P; Reynolds, J E; James, C W; Phillips, C J; Protheroe, R J; McFadden, R A; Aartsen, M G

    2015-01-01T23:59:59.000Z

    We report a limit on the ultra-high-energy neutrino flux based on a non-detection of radio pulses from neutrino-initiated particle cascades in the Moon, in observations with the Parkes radio telescope undertaken as part of the LUNASKA project. Due to the improved sensitivity of these observations, which had an effective duration of 127 hours and a frequency range of 1.2-1.5 GHz, this limit extends to lower neutrino energies than those from previous lunar radio experiments, with a detection threshold below 10^20 eV. The calculation of our limit allows for the possibility of lunar-origin pulses being misidentified as local radio interference, and includes the effect of small-scale lunar surface roughness. The targeting strategy of the observations also allows us to place a directional limit on the neutrino flux from the nearby radio galaxy Centaurus A.

  4. Cognitive Radio and Smart Grid Dr. Robert C. Qiu

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Cognitive Radio and Smart Grid Dr. Robert C. Qiu Professor Wireless Networking Systems Laboratory RadioCognitive Radio 2 2/23/2010 #12;Outline Cognitive Radio Cognitive Radio @ Tennessee Tech University Spectrum Sensing and Wideband Spectrum Sensing Cognitive Radio Networks and Testbeds Cognitive

  5. Telecommunications Emergency Alert System (EAS) Radio

    E-Print Network [OSTI]

    Telecommunications Emergency Alert System (EAS) Radio 1. Send completed form to Mail Stop of submitting this form, call 979.845.1020. In the event the radio is lost or broken, the department will be charged for a replacement. If the radio malfunctions, please contact Telecommunications. Texas A

  6. FAINT RADIO SOURCES AND STAR FORMATION HISTORY

    E-Print Network [OSTI]

    Waddington, Ian

    FAINT RADIO SOURCES AND STAR FORMATION HISTORY Deborah B. Haarsma 1 , R. Bruce Partridge 1 , Ian 85287­1504 USA Abstract. Faint extragalactic radio sources provide important information about the global history of star formation. Sensitive radio observations of the Hubble Deep Field and other fields

  7. > RADIO TUDIANTE CISM 89,3 FM

    E-Print Network [OSTI]

    Charette, André

    3 0 > RADIO ÉTUDIANTE ­ CISM 89,3 FM Pavillon J.-A.-DeSève 2332, boul. Édouard-Montpetit Local C@pol.umontreal.ca Revue du Département de science politique de l'UdeM. Radio > ATELIERS DE FORMATION EN RADIO (ACTIVITÉS

  8. Analysis of modulation scheme using GNU Radio

    E-Print Network [OSTI]

    Yu, Chansu

    1 Analysis of modulation scheme using GNU Radio By: Zeyu long Outline Introduce Project Goal QPSK CPFSK Resolute Project conclusion Project challenges Reference #12;2 Introduce (1) GNU radio: One of the most popular applications of Software Defined Radios Use C++ to write blocks Use python to connect

  9. Radio Network Planning with Combinatorial Optimisation Algorithms

    E-Print Network [OSTI]

    Boyer, Edmond

    Radio Network Planning with Combinatorial Optimisation Algorithms P. Calégari, F. Guidec, P. Kuonen@c2r.tdf.fr Group: Software tools Abstract: Future UMTS radio planning engineers will face difficult, a software for the optimisation of the radio network is under development. Two mathematical models

  10. Radio Linear and Circular Polarization from M81*

    E-Print Network [OSTI]

    Andreas Brunthaler; Geoffrey C. Bower; Heino Falcke

    2006-05-05T23:59:59.000Z

    We present results from archival Very Large Array (VLA) data and new VLA observations to investigate the long term behavior of the circular polarization of M81*, the nuclear radio source in the nearby galaxy M81. We also used the Berkeley-Illinois-Maryland Association (BIMA) array to observe M81* at 86 and 230 GHz. M81* is unpolarized in the linear sense at a frequency as high as 86 GHz and shows variable circular polarization at a frequency as high as 15 GHz. The spectrum of the fractional circular polarization is inverted in most of our observations. The sign of circular polarization is constant over frequency and time. The absence of linear polarization sets a lower limit to the accretion rate of $10^{-7} M_\\odot y^{-1}$. The polarization properties are strikingly similar to the properties of Sgr A*, the central radio source in the Milky Way. This supports the hypothesis that M81* is a scaled up version of Sgr A*. On the other hand, the broad band total intensity spectrum declines towards milimeter wavelengths which differs from previous observations of M81* and also from Sgr A*.

  11. Wave-wave interactions in solar type III radio bursts

    SciTech Connect (OSTI)

    Thejappa, G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); MacDowall, R. J. [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)

    2014-02-11T23:59:59.000Z

    The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.

  12. Detection of the thermal radio continuum emission from the G9.62+0.19-F Hot Core

    E-Print Network [OSTI]

    L. Testi; P. Hofner; S. Kurtz; M. Rupen

    2000-06-15T23:59:59.000Z

    We present new high resolution and high sensitivity multi-frequency VLA radio continuum observations of the G9.62+0.19-F hot molecular core. We detect for the first time faint centimetric radio continuum emission at the position of the core. The centimetric continuum spectrum of the source is consistent with thermal emission from ionised gas. This is the first direct evidence that a newly born massive star is powering the G9.62+0.19-F hot core.

  13. Radio Pumping of Ionospheric Plasma with Orbital Angular Momentum

    SciTech Connect (OSTI)

    Leyser, T. B. [Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala (Sweden); Norin, L. [Department of Physics and Astronomy, Uppsala University, Box 515, Uppsala SE-751 20 (Sweden); McCarrick, M. [BAE SYSTEMS Advanced Technologies, 1250 24th St, NW, Suite 850, Washington, D.C. (United States); Pedersen, T. R. [Air Force Research Laboratory, Hanscom Air Force Base, Massachusetts 01731 (United States); Gustavsson, B. [Department of Physics and Technology, University of Tromsoe, N-9037 Tromsoe (Norway)

    2009-02-13T23:59:59.000Z

    Experimental results are presented of pumping ionospheric plasma with a radio wave carrying orbital angular momentum (OAM), using the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Optical emissions from the pumped plasma turbulence exhibit the characteristic ring-shaped morphology when the pump beam carries OAM. Features of stimulated electromagnetic emissions (SEE) that are attributed to cascading Langmuir turbulence are well developed for a regular beam but are significantly weaker for a ring-shaped OAM beam in which case upper hybrid turbulence dominates the SEE.

  14. Frequency Measurement & Analysis Service

    E-Print Network [OSTI]

    Magee, Joseph W.

    NIST Frequency Measurement & Analysis Service #12;A Complete Solution To All Frequency Measurement & Calibration Problems The NIST Frequency Measurement and Analysis Service makes it easy to measure and calibrate any quartz, rubidium, or cesium frequency standard. All measurements are made automatically

  15. LOW-FREQUENCY OBSERVATIONS OF THE MOON WITH THE MURCHISON WIDEFIELD ARRAY

    SciTech Connect (OSTI)

    McKinley, B.; Briggs, F. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Greenhill, L. J.; Bernardi, G.; De Oliveira-Costa, A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Tingay, S. J.; Gaensler, B. M. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), School of Physics, The University of Sydney, Sydney, NSW (Australia); Oberoi, D. [National Centre for Radio Astrophysics, Tata Institute for Fundamental Research, Pune (India); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand); Arcus, W.; Emrich, D. [International Centre for Radio Astronomy Research, Curtin University, Perth (Australia); Barnes, D. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bunton, J. D. [CSIRO Astronomy and Space Science, Canberra (Australia); Cappallo, R. J.; Corey, B. E. [MIT Haystack Observatory, Westford, MA (United States); Deshpande, A. [Raman Research Institute, Bangalore (India); DeSouza, L. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney (Australia); Goeke, R. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); and others

    2013-01-01T23:59:59.000Z

    A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21 cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300 MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of the Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system.

  16. Damage Identification Study of a Seven-story Full-scale Building Slice Tested on the UCSD-NEES Shake Table

    E-Print Network [OSTI]

    Moaveni, Babak; He, Xianfei; Resterpo, Jose I; Conte, Joel P

    2010-01-01T23:59:59.000Z

    Restrepo JI, Elgamal A. Damage identification of a seven-review of vibration-based damage identifi- cation methods.Detection of structural damage through changes in frequency:

  17. The Nature of Radio-Intermediate Quasars: What is Radio-Loud and what is Radio-Quiet?

    E-Print Network [OSTI]

    Heino Falcke; William Sherwood; Alok Patnaik

    1996-05-27T23:59:59.000Z

    We have performed quasi-simultaneous radio flux density measurements at 2.7 and 10 GHz for all PG quasars with radio flux densities between 4-200 mJy. We find that a large fraction of these sources are variable, flat-spectrum quasars. This brings the total fraction of flat-spectrum quasars with a ratio between radio and optical flux of R>10 - a value previously used to define a radio-loud quasar - to 40% in the PG quasar sample. We also find that the median R-parameter of these flat-spectrum quasars is lower than those of steep-spectrum radio-loud quasars. This contradicts the predictions of the unified scheme and the idea that all flat-spectrum, core-dominated quasars are relativistically boosted lobe-dominated quasars. We show that this discrepancy is due to a population of flat-spectrum radio-intermediate quasars with 25radio-loud quasars nor as normal radio-weak quasars. We point out that a natural explanation for the flat-spectrum radio-intermediate quasars is relativistic boosting in radio-weak quasars. If the flat-spectrum radio-intermediate quasars are considered the boosted counterparts to usual radio-weak quasars, their fraction among radio-weak quasars is roughly 10%, similar to the fraction of boosted radio-loud quasars. This would point towards average Lorentz factors of gamma_jet=2-4 for radio-loud and radio-weak quasars. The presence of the flat-spectrum radio-intermediate quasars changes the definition of 'radio-loud' and can bias some conclusions drawn from optically selected quasar samples, where R ~ 1-10 is used as the dividing line for both, flat- and steep-spectrum quasars. Instead one should use separate R-parameters for the dividing line in steep- (R~25) and flat-spectrum (R~250) quasars.

  18. A Type II Radio Burst without a Coronal Mass Ejection

    E-Print Network [OSTI]

    Su, W; Ding, M D; Chen, P F; Sun, J Q

    2015-01-01T23:59:59.000Z

    Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II radio burst is not accompanied by a coronal mass ejection, only with a C2.4 class flare and narrow jet. However, in the extreme-ultraviolet (EUV) images provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), we find a wave-like structure that propagated at a speed of $\\sim$ 600 km s$^{-1}$ during the burst. The relationship between the type II radio burst and the wave-like structure is in particular explored. For this purpose, we first derive the density distribution under the wave by the differential emission measure (DEM) method, which is used to restrict the empirical density model. We then use the restricted density model to invert the speed of the shock that produces the observed frequency drift rate in the dynamic spectrum. The ...

  19. Progress in ultra high energy neutrino experiments using radio techniques

    SciTech Connect (OSTI)

    Liu Jiali [Physics department, Kunming University, Kunming, 650214 (China); Tiedt, Douglas [Physics department, South Dakota School of Mines and Technology, Rapid City, SD, 57701-3995 (United States)

    2013-05-23T23:59:59.000Z

    Studying the source of Ultra High Energy Cosmic Ray (UHECR) can provide important clues on the understanding of UHE particle physics, astrophysics, and other extremely energetic phenomena in the universe. However, charged CR particles are deflected by magnetic fields and can not point back to the source. Furthermore, UHECR charged particles above the Greisen-Zatsepin-Kuzmin (GZK) cutoff (about 5 Multiplication-Sign 10{sup 19} eV) suffer severe energy loss due to the interaction with the Cosmic Microwave Background Radiation (CMBR). Consequently almost all the information carried by CR particles about their origin is lost. Neutrinos, which are neutral particles and have extremely weak interactions with other materials can arrive at the earth without deflection and absorption. Therefore UHE neutrinos can be traced back to the place where they are produced. Due to their weak interaction and ultra high energies (thus extremely low flux) the detection of UHE neutrinos requires a large collecting area and massive amounts of material. Cherenkov detection at radio frequency, which has long attenuation lengths and can travel freely in natural dense medium (ice, rock and salt et al), can fulfill the detection requirement. Many UHE neutrino experiments are being performed by radio techniques using natural ice, lunar, and salt as detection mediums. These experiments have obtained much data about radio production, propagation and detection, and the upper limit of UHE neutrino flux.

  20. Coherent Radio Pulses From GEANT Generated Electromagnetic Showers In Ice

    E-Print Network [OSTI]

    Soebur Razzaque; Surujhdeo Seunarine; David Z. Besson; Douglas W. McKay; John P. Ralston; David Seckel

    2002-02-25T23:59:59.000Z

    Radio Cherenkov radiation is arguably the most efficient mechanism for detecting showers from ultra-high energy particles of 1 PeV and above. Showers occuring in Antarctic ice should be detectable at distances up to 1 km. We report on electromagnetic shower development in ice using a GEANT Monte Carlo simulation. We have studied energy deposition by shower particles and determined shower parameters for several different media, finding agreement with published results where available. We also report on radio pulse emission from the charged particles in the shower, focusing on coherent emission at the Cherenkov angle. Previous work has focused on frequencies in the 100 MHz to 1 GHz range. Surprisingly, we find that the coherence regime extends up to tens of Ghz. This may have substantial impact on future radio-based neutrino detection experiments as well as any test beam experiment which seeks to measure coherent Cherenkov radiation from an electromagnetic shower. Our study is particularly important for the RICE experiment at the South Pole.

  1. RADIO CONTROL ADC0 (RSSI)

    E-Print Network [OSTI]

    5 5 4 4 3 3 2 2 1 1 D D C C B B A A RADIO CONTROL PCLK PDATA PALE RADIO DATA SPI_SCK SPI_MOSI SPI_MISO[0..7] PALE RF_DETECT US_OUT_EN SPI_MISO I2C_CLK I2C_DATA US_DETECT AC+ US_OUT SCK RSTN UART_RXD0/SS PB1/SCK PB2/MOSI PB3/MISO PB4/OC0 PB5/OC1A PB6/OC1B PB7/OC1C PC0/A8 PC1/A9 PC2/A10 PC3/A11 PC4/A12

  2. Radio Observations of Supernova Remnants

    E-Print Network [OSTI]

    W. Reich

    2002-08-28T23:59:59.000Z

    Supernovae release an enormous amount of energy into the interstellar medium. Their remnants can observationally be traced up to several ten-thousand years. So far more than 230 Galactic supernova remnants (SNRs) have been identified in the radio range. Detailed studies of the different types of SNRs give insight into the interaction of the blast wave with the interstellar medium. Shock accelerated particles are observed, but also neutron stars left from the supernova explosion make their contribution. X-ray observations in conjunction with radio data constrain models of supernova evolution. A brief review of the origin and evolution of SNRs is given, which are compared with supernova statistics and observational limitations. In addition the morphology and characteristics of the different types of SNRs are described, including some recent results and illustrated by SNRs images mostly obtained with the Effelsberg 100-m telescope.

  3. The Host Galaxies of Radio-Loud and Radio-Quiet Quasars

    E-Print Network [OSTI]

    James S. Dunlop

    2001-03-15T23:59:59.000Z

    I review our knowledge of the properties of the host galaxies of radio-loud and radio-quiet quasars, both in comparison to each other and in the context of the general galaxy population. It is now clear that the hosts of radio-loud and radio-quiet quasars with M_V 10^9 solar masses appears to be a necessary (although perhaps not sufficient) condition for the production of radio jets of sufficient power to produce an FRII radio source within a massive galaxy halo.

  4. Antenna unit and radio base station therewith

    DOE Patents [OSTI]

    Kuwahara, Mikio; Doi, Nobukazu; Suzuki, Toshiro; Ishida, Yuji; Inoue, Takashi; Niida, Sumaru

    2007-04-10T23:59:59.000Z

    Phase and amplitude deviations, which are generated, for example, by cables connecting an array antenna of a CDMA base station and the base station, are calibrated in the baseband. The base station comprises: an antenna apparatus 1; couplers 2; an RF unit 3 that converts a receive signal to a baseband signal, converts a transmit signal to a radio frequency, and performs power control; an A/D converter 4 for converting a receive signal to a digital signal; a receive beam form unit 6 that multiplies the receive signal by semi-fixed weight; a despreader 7 for this signal input; a time-space demodulator 8 for demodulating user data; a despreader 9 for probe signal; a space modulator 14 for user data; a spreader 13 for user signal; a channel combiner 12; a Tx calibrater 11 for controlling calibration of a signal; a D/A converter 10; a unit 16 for calculation of correlation matrix for generating a probe signal used for controlling an Rx calibration system and a TX calibration system; a spreader 17 for probe signal; a power control unit 18; a D/A converter 19; an RF unit 20 for probe signal; an A/D converter 21 for signal from the couplers 2; and a despreader 22.

  5. Radio-transparent multi-layer insulation for radiowave receivers

    SciTech Connect (OSTI)

    Choi, J. [Korea University, Anam-dong Seongbuk-gu, Seoul 136-713 (Korea, Republic of)] [Korea University, Anam-dong Seongbuk-gu, Seoul 136-713 (Korea, Republic of); Ishitsuka, H. [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan)] [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Mima, S. [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Oguri, S., E-mail: shugo@post.kek.jp [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan); Takahashi, K. [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan) [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Tajima, O. [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan) [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2013-11-15T23:59:59.000Z

    In the field of radiowave detection, enlarging the receiver aperture to enhance the amount of light detected is essential for greater scientific achievements. One challenge in using radio transmittable apertures is keeping the detectors cool. This is because transparency to thermal radiation above the radio frequency range increases the thermal load. In shielding from thermal radiation, a general strategy is to install thermal filters in the light path between aperture and detectors. However, there is difficulty in fabricating metal mesh filters of large diameters. It is also difficult to maintain large diameter absorptive-type filters in cold because of their limited thermal conductance. A technology that maintains cold conditions while allowing larger apertures has been long-awaited. We propose radio-transparent multi-layer insulation (RT-MLI) composed from a set of stacked insulating layers. The insulator is transparent to radio frequencies, but not transparent to infrared radiation. The basic idea for cooling is similar to conventional multi-layer insulation. It leads to a reduction in thermal radiation while maintaining a uniform surface temperature. The advantage of this technique over other filter types is that no thermal links are required. As insulator material, we used foamed polystyrene; its low index of refraction makes an anti-reflection coating unnecessary. We measured the basic performance of RT-MLI to confirm that thermal loads are lowered with more layers. We also confirmed that our RT-MLI has high transmittance to radiowaves, but blocks infrared radiation. For example, RT-MLI with 12 layers has a transmittance greater than 95% (lower than 1%) below 200 GHz (above 4 THz). We demonstrated its effects in a system with absorptive-type filters, where aperture diameters were 200 mm. Low temperatures were successfully maintained for the filters. We conclude that this technology significantly enhances the cooling of radiowave receivers, and is particularly suitable for large-aperture systems. This technology is expected to be applicable to various fields, including radio astronomy, geo-environmental assessment, and radar systems.

  6. Sources of the Radio Background Considered

    SciTech Connect (OSTI)

    Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22T23:59:59.000Z

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  7. Processing of superconductive materials and high frequency

    SciTech Connect (OSTI)

    Smith, J.L.

    1987-01-01T23:59:59.000Z

    We do not know yet if superconductivity will become useful without refrigeration. Now, the superconductors are so different from copper that it is difficult to imagine replacing copper with such a brittle material. Superconductors conduct dc with no loss, ac with small losses, and microwaves in co-axial lines with almost no loss and with no dispersion from dc to the highest frequencies. They will probably allow us to close the gap between radio frequency and infrared optical transmission. Clearly your industry should know some things about where superconductivity may lead us and must consider whether the greater risk is to develop them or to let others try it. There are no easy answers yet.

  8. Measurement of the gravitational redshift effect with RadioAstron satellite

    E-Print Network [OSTI]

    Birukov, A V; Litvinov, D A; Porayko, N K; Rudenko, V N

    2015-01-01T23:59:59.000Z

    RadioAstron satellite admits in principle a testing the gravitational redshift effect with an accuracy of better than $10^{-5}$. It would surpass the result of Gravity Probe A mission at least an order of magnitude. However, RadioAstron's communications and frequency transfer systems are not adapted for a direct application of the non relativistic Doppler and troposphere compensation scheme used in the Gravity Probe A experiment. This leads to degradation of the redshift test accuracy approximately to the level 0.01. We discuss the way to overcome this difficulty and present preliminary results based on data obtained during special observing sessions scheduled for testing the new techniques.

  9. Measurement of the gravitational redshift effect with RadioAstron satellite

    E-Print Network [OSTI]

    A. V. Birukov; V. L. Kauts; D. A. Litvinov; N. K. Porayko; V. N. Rudenko

    2015-06-07T23:59:59.000Z

    RadioAstron satellite admits in principle a testing the gravitational redshift effect with an accuracy of better than $10^{-5}$. It would surpass the result of Gravity Probe A mission at least an order of magnitude. However, RadioAstron's communications and frequency transfer systems are not adapted for a direct application of the non relativistic Doppler and troposphere compensation scheme used in the Gravity Probe A experiment. This leads to degradation of the redshift test accuracy approximately to the level 0.01. We discuss the way to overcome this difficulty and present preliminary results based on data obtained during special observing sessions scheduled for testing the new techniques.

  10. EVN+MERLIN Observations of Radio-Intermediate Quasars: Evidence for Boosted Radio-Weak Quasars

    E-Print Network [OSTI]

    Heino Falcke; Alok Patnaik; William Sherwood

    1996-10-08T23:59:59.000Z

    We present VLBI (EVN+MERLIN) observations of a sample of three low-redshift radio-intermediate PG quasars (RIQ) with flat and variable radio spectrum (III Zw 2, PG 1309+355, PG 2209+184). Their radio-to-optical flux ratio (R) is slightly lower than the average R for steep-spectrum quasars, but their radio spectral properties are those of core-dominated quasars. It was proposed previously that these sources might be relativistically boosted jets in radio-weak quasars. Our VLBI observations now indeed confirm the presence of a high brightness temperature core in all three of these objects --- two of them have lower limits on T_B well in excess of 10^10 Kelvin. Moreover, we find no ``missing-flux'' which means that basically all the flux of these quasars is concentrated in the compact radio core. As the total radio flux is already at the low end for radio-loud quasars, we can place a strong limit on the presence of any extended emission. This limit is consistent with the extended emission in radio-weak quasars, but excludes that the flat-spectrum RIQ reside in typical radio-loud quasars. The observations therefore strongly support the idea that relativistic jets are present in radio-weak quasars and hence that radio-loud and radio-weak quasars have very similar central engines.

  11. Field Deployment of Prototype Antenna Tiles for the Mileura Widefield Array--Low Frequency Demonstrator

    E-Print Network [OSTI]

    Judd D. Bowman; David G. Barnes; Frank H. Briggs; Brian E. Corey; Merv J. Lynch; N. D. Ramesh Bhat; Roger J. Cappallo; Sheperd S. Doeleman; Brian J. Fanous; David Herne; Jacqueline N. Hewitt; Chris Johnston; Justin C. Kasper; Jonathon Kocz; Eric Kratzenberg; Colin J. Lonsdale; Miguel F. Morales; Divya Oberoi; Joseph E. Salah; Bruce Stansby; Jamie Stevens; Glen Torr; Randall Wayth; Rachel L. Webster; J. Stuart B. Wyithe

    2006-12-01T23:59:59.000Z

    Experiments were performed with prototype antenna tiles for the Mileura Widefield Array--Low Frequency Demonstrator (MWA-LFD) to better understand the widefield, wideband properties of their design and to characterize the radio frequency interference (RFI) between 80 and 300 MHz at the site in Western Australia. Observations acquired during the six month deployment confirmed the predicted sensitivity of the antennas, sky-noise dominated system temperatures, and phase-coherent interferometric measurements. The radio spectrum is remarkably free of strong terrestrial signals, with the exception of two narrow frequency bands allocated to satellite downlinks and rare bursts due to ground-based transmissions being scattered from aircraft and meteor trails. Results indicate the potential of the MWA-LFD to make significant achievements in its three key science objectives: epoch of reionziation science, heliospheric science, and radio transient detection.

  12. Radio-telemetry equipment and applications for carnivores

    E-Print Network [OSTI]

    Schweik, Charles M.

    7 Radio-telemetry equipment and applications for carnivores Mark R. Fuller and Todd K. Fuller Radio goals for this chapter are to provide basic information about radio-telemetry equipment and procedures's (2001) comprehensive book, A manual of wildlife radio tagging for persons who are unfamiliar with radio

  13. Unveiling the nature of the unidentified gamma-ray sources VI: gamma-ray blazar candidates in the WISH survey and their radio properties

    E-Print Network [OSTI]

    Nori, M; Massaro, F; D'Abrusco, R; Paggi, A; Tosti, G; Funk, S

    2015-01-01T23:59:59.000Z

    According to the second Fermi LAT Catalog (2FGL), about one third of the gamma-ray sources listed have no assigned counterparts at lower energies. Many statistical methods have been developed to find proper counterparts for these sources. We explore the sky area covered at low radio frequency by Westerbork in the Southern Hemisphere (WISH) survey to search for blazar-like associations among the unidentified gamma-ray sources listed in the 2FGL (UGSs). Searching the WISH and NRAO VLA Sky Survey (NVSS) radio surveys within the positional uncertainty regions of the 2FGL UGSs, we select as gamma-ray blazar candidates the radio sources characterized by flat radio spectra between 352 MHz and 1400 MHz. We propose new gamma-ray blazar associations for eight UGSs and we also discuss their spectral properties at low radio frequencies. We compare the radio flux density distribution of the low radio frequency gamma-ray blazar candidates with that of gamma-ray blazars associated with other methods. We find significant dif...

  14. Eastern Frequency Response Study

    SciTech Connect (OSTI)

    Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

    2013-05-01T23:59:59.000Z

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  15. Blind Equalization and Identification for Differential Space-time Modulated Communication Systems

    E-Print Network [OSTI]

    Schniter, Philip

    Blind Equalization and Identification for Differential Space-time Modulated Communication Systems A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science of blind identification and equalization for MIMO system with frequency- selective fading channels. We

  16. Identification in Prediction Theory

    E-Print Network [OSTI]

    Bielefeld, University of

    Identification in Prediction Theory Lars B¨aumer Bielefeld 2000 #12;Acknowledgment I wish to thank remarks. 1 #12;Contents 1 Introduction 3 2 Finite-State Predictability 7 2.1 A Universal Predictor Predictability and Identifiability . . . . . . 30 3.3 Markov Machines for Identification

  17. Frequency selective infrared sensors

    SciTech Connect (OSTI)

    Davids, Paul; Peters, David W

    2014-11-25T23:59:59.000Z

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  18. Frequency selective infrared sensors

    DOE Patents [OSTI]

    Davids, Paul; Peters, David W

    2013-05-28T23:59:59.000Z

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  19. Cognitive Radio Network {swjang, sbahk}@netlab.snu.ac.kr

    E-Print Network [OSTI]

    Bahk, Saewoong

    2010 Cognitive Radio Network , , {swjang, sbahk}@netlab.snu.ac.kr Analysis of Average Opportunities in Cognitive Radio Networks Seowoo Jang, Saewoong Bahk INMC, EECS, Seoul National University Cognitive Radio Network . Primary user

  20. Experimental methodology for non-thermal effects of electromagnetic radiation on biologics

    E-Print Network [OSTI]

    Cox, Felicia C. A. I

    2006-01-01T23:59:59.000Z

    Appropriate equipment is needed for research on the effects of radio-frequency radiation from radio-frequency identification (RF-ID) systems on biological materials. In the present study, a complete test system comprising ...

  1. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    SciTech Connect (OSTI)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01T23:59:59.000Z

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  2. NATIONAL RADIO ASTRONOMY OBSERVATORY GREEN BANK, WEST VIRGINIA

    E-Print Network [OSTI]

    Groppi, Christopher

    NATIONAL RADIO ASTRONOMY OBSERVATORY GREEN BANK, WEST VIRGINIA ELECTRONICS DIVISION TECHNICAL NOTE R. Lacasse #12;NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia 140-ft CASSEGRAIN BAa

  3. Using Radio Waves to Control Fusion Plasma Density

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Using Radio Waves to Control Fusion Plasma Density Using Radio Waves to Control Fusion Plasma Density Simulations Run at NERSC Support Fusion Experiments at MIT, General Atomics...

  4. WAVELET TRANSFORMS FOR SYSTEM IDENTIFICATION AND ASSOCIATED PROCESSING CONCERNS

    E-Print Network [OSTI]

    Kareem, Ahsan

    WAVELET TRANSFORMS FOR SYSTEM IDENTIFICATION AND ASSOCIATED PROCESSING CONCERNS Tracy L. Kijewski1 , Student Member ASCE and Ahsan Kareem2 , Member ASCE ABSTRACT The time-frequency character of wavelet-domain transform, particularly for the popular Morlet wavelet. Unfortunately, in prior applications of wavelet

  5. 1. Identification Number: 2. Program/Project Title: 3. Recipient

    E-Print Network [OSTI]

    Personal Property Report Forms Family Other(see special instructions) Frequency Addressees1 1. Identification Number: 2. Program/Project Title: 3. Recipient: 4. Reporting Requirements: A. MANAGEMENT REPORTING Research Performance Progress Report (RPPR) (RD&D Projects) Progress Report (Non

  6. LIMITS ON PROMPT, DISPERSED RADIO PULSES FROM GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Bannister, K. W.; Murphy, T.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics A29, University of Sydney, NSW 2006 (Australia); Reynolds, J. E., E-mail: keith.bannister@csiro.au [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

    2012-09-20T23:59:59.000Z

    We have searched for prompt radio emission from nine gamma-ray bursts (GRBs) with a 12 m telescope at 1.4 GHz, with a time resolution of 64 {mu}s to 1 s. We detected single dispersed radio pulses with significances >6{sigma} in the few minutes following two GRBs. The dispersion measures of both pulses are well in excess of the expected Galactic values, and the implied rate is incompatible with known sources of single dispersed pulses. The arrival times of both pulses also coincide with breaks in the GRB X-ray light curves. A null trial and statistical arguments rule out random fluctuations as the origin of these pulses with >95% and {approx}97% confidence, respectively, although a simple population argument supports a GRB origin with confidence of only 2%. We caution that we cannot rule out radio frequency interference (RFI) as the origin of these pulses. If the single pulses are not related to the GRBs, we set an upper limit on the flux density of radio pulses emitted between 200 and 1800 s after a GRB of 1.27w {sup -1/2} Jy, where 6.4 Multiplication-Sign 10{sup -5} s < w < 32 Multiplication-Sign 10{sup -3} s is the pulse width. We set a limit of less than 760 Jy for long timescale (>1 s) variations. These limits are some of the most constraining at high time resolution and GHz frequencies in the early stages of the GRB phenomenon.

  7. Limits on Fast Radio Bursts at 145 MHz with ARTEMIS, a real-time software backend

    E-Print Network [OSTI]

    Karastergiou, A; Armour, W; Williams, C; Mort, B; Dulwich, F; Salvini, S; Magro, A; Roberts, S; Serylak, M; Doo, A; Bilous, A V; Breton, R P; Falcke, H; Griessmeier, J -M; Hessels, J W T; Keane, E F; Kondratiev, V I; Kramer, M; van Leeuwen, J; Noutsos, A; Oslowski, S; Sobey, C; Stappers, B W; Weltevrede, P

    2015-01-01T23:59:59.000Z

    Fast Radio Bursts (FRBs), are millisecond radio signals that exhibit dispersion larger than what the Galactic electron density can account for. We have conducted a 1446 hour survey for Fast Radio Bursts (FRBs) at 145~MHz, covering a total of 4193 sq. deg on the sky. We used the UK station of the LOFAR radio telescope -- the Rawlings Array -- , accompanied for a majority of the time by the LOFAR station at Nan\\c{c}ay, observing the same fields at the same frequency. Our real-time search backend, ARTEMIS, utilizes graphics processing units to search for pulses with dispersion measures up to 320 cm$^{-3}$ pc. Previous derived FRB rates from surveys around 1.4~GHz, and favoured FRB interpretations, motivated this survey, despite all previous detections occurring at higher dispersion measures. We detected no new FRBs above a signal-to-noise threshold of 10, leading to the most stringent upper limit yet on the FRB event rate at these frequencies: 29 sky$^{-1}$ day$^{-1}$ for 5~ms-duration pulses above 62~Jy. The no...

  8. Radio to gamma-ray variability study of blazar S5 0716+714

    E-Print Network [OSTI]

    Rani, B; Fuhrmann, L; Boettcher, M; Lott, B; Aller, H D; Aller, M F; Angelakis, E; Bach, U; Bastieri, D; Falcone, A D; Fukazawa, Y; Gabanyi, K E; Gupta, A C; Gurwell, M; Itoh, R; Kawabata, K S; Krips, M; Lähteenmäki, A A; Liu, X; Marchili, N; Max-Moerbeck, W; Nestoras, I; Nieppola, E; Quintana-Lacaci, G; Readhead, A C S; Richards, J L; Sasada, M; Sievers, A; Sokolovsky, K; Stroh, M; Tammi, J; Tornikoski, M; Uemura, M; Ungerechts, H; Urano, T; Zensus, J A

    2013-01-01T23:59:59.000Z

    We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and space based facilities. The intense optical monitoring of the source reveals faster repetitive variations superimposed on a long-term variability trend at a time scale of ~350 days. Episodes of fast variability recur on time scales of ~ 60-70 days. The intense and simultaneous activity at optical and gamma-ray frequencies favors the SSC mechanism for the production of the high-energy emission. Two major low-peaking radio flares were observed during this high optical/gamma-ray activity period. The radio flares are characterized by a rising and a decaying stage and are in agreement with the formation of a shock and its evolution. We found that the evolution of the radio flares requires a geometrical variation in addition to intrinsic variations of the source. Different estima...

  9. High-Resolution Radio Imaging of Gravitational Lensing Candidates in the 1 Jansky BL Lac Sample

    E-Print Network [OSTI]

    T. A. Rector; J. T. Stocke

    2003-02-19T23:59:59.000Z

    While BL Lacertae objects are widely believed to be highly beamed, low-luminosity radio galaxies, many radio-selected BL Lacs have extended radio power levels and optical emission lines that are too luminous to be low-luminosity radio galaxies. Also, Stocke & Rector discovered an excess of MgII absorption systems along BL Lac sightlines compared to quasars, suggesting that gravitational lensing may be another means of creating the BL Lac phenomenon in some cases. We present a search for gravitationally-lensed BL Lacs with deep, high-resolution, two-frequency VLA radio maps of seven lensing candidates from the 1 Jansky BL Lac sample. We find that none of these objects are resolved into an Einstein ring like B 0218+357, nor do any show multiple images of the core. All of the lensing candidates that were resolved show a flat-spectrum core and very unusual, steep-spectrum extended morphology that is incompatible with a multiply lensed system. Thus, while these observations do not rule out microlensing, no macrolensing is observed.

  10. On the integrated continuum radio-spectrum of supernova remnant W44 (G34.7-0.4): new insights from Planck's data

    E-Print Network [OSTI]

    Oni?, D

    2015-01-01T23:59:59.000Z

    In this paper, the integrated continuum radio-spectrum of supernova remnant (SNR) W44 was analyzed up to 70 GHz, testing the different emission models that can be responsible for its particular shape. {\\it Planck's} observations made possible to analyze the high frequency part of radio-emission from SNRs. Although the quality of radio-continuum spectrum (a high scatter of data points at same frequencies) prevents us to make definite conclusions, we emphasize the possibility of spinning-dust emission detection towards this remnant. In addition, a concave-down feature, due to synchrotron losses, can not be definitely dismissed by the present knowledge of the integrated radio continuum spectrum of this SNR.

  11. A Probabilistic Model of Spectrum Occupancy, User Activity, and System Throughput for OFDMA based Cognitive Radio Systems 

    E-Print Network [OSTI]

    Rahimian, Nariman

    2013-05-07T23:59:59.000Z

    .2 Overview on Orthogonal Frequency Division Multiple Access . . . . . 3 1.3 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.4 Overview on IEEE Standards Supporting Cognitive Radio and Dy- namic Spectrum Access.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 APPENDIX E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 viii APPENDIX F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 ix LIST OF FIGURES FIGURE Page 1.1 The evolution of IEEE...

  12. On the continuum radio-spectrum of Cas A: possible evidence of the non-linear particle acceleration

    E-Print Network [OSTI]

    Oni?, D

    2015-01-01T23:59:59.000Z

    Integrated radio-spectrum of Cas A in continuum was analyzed with special emphasis on possible high frequency spectral curvature. We conclude that the most probable scenario is that Planck's new data reveal the imprint of non-linear particle acceleration in the case of this young Galactic supernova remnant (SNR).

  13. Frequency Response Analysis Tool

    SciTech Connect (OSTI)

    Etingov, Pavel V.; Kosterev, Dmitry; Dai, T.

    2014-12-31T23:59:59.000Z

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  14. Non-linear system identification in flow-induced vibration

    SciTech Connect (OSTI)

    Spanos, P.D.; Zeldin, B.A. [Rice Univ., Houston, TX (United States); Lu, R. [Hudson Engineering Corp., Houston, TX (United States)

    1996-12-31T23:59:59.000Z

    The paper introduces a method of identification of non-linear systems encountered in marine engineering applications. The non-linearity is accounted for by a combination of linear subsystems and known zero-memory non-linear transformations; an equivalent linear multi-input-single-output (MISO) system is developed for the identification problem. The unknown transfer functions of the MISO system are identified by assembling a system of linear equations in the frequency domain. This system is solved by performing the Cholesky decomposition of a related matrix. It is shown that the proposed identification method can be interpreted as a {open_quotes}Gram-Schmidt{close_quotes} type of orthogonal decomposition of the input-output quantities of the equivalent MISO system. A numerical example involving the identification of unknown parameters of flow (ocean wave) induced forces on offshore structures elucidates the applicability of the proposed method.

  15. New Measurements of the Radio Photosphere of Mira based on Data from the JVLA and ALMA

    E-Print Network [OSTI]

    Matthews, L D; Menten, K M

    2015-01-01T23:59:59.000Z

    We present new measurements of the millimeter wavelength continuum emission from the long period variable Mira ($o$ Ceti) at frequencies of 46 GHz, 96 GHz, and 229 GHz ($\\lambda$~7 mm, 3 mm, and 1 mm) based on observations obtained with the Jansky Very Large Array (JVLA) and the Atacama Large Millimeter/submillimeter Array (ALMA). The measured millimeter flux densities are consistent with a radio photosphere model derived from previous observations, where flux density, $S_{\

  16. IRAS F02044+0957 radio source in interacting system of galaxies

    E-Print Network [OSTI]

    Verkhodanov, O V; Mujica, R; Valdés, J R; Trushkin, S A

    2001-01-01T23:59:59.000Z

    The steep spectrum of IRAS F02044+0957 was obtained with the RATAN-600 radio telescope at four frequencies. Optical spectroscopy of the system components, was carried out with the 2.1m telescope of the Guillermo Haro Observatory. Observational data allow us to conclude that this object is a pair of interacting galaxies, a LINER and a HII galaxy, at $z=0.093$.

  17. IRAS F02044+0957: radio source in interacting system of galaxies

    E-Print Network [OSTI]

    O. V. Verkhodanov; V. H. Chavushyan; R. Mújica; J. R. Valdés; S. A. Trushkin

    2001-12-06T23:59:59.000Z

    The steep spectrum of IRAS F02044+0957 was obtained with the RATAN-600 radio telescope at four frequencies. Optical spectroscopy of the system components, was carried out with the 2.1m telescope of the Guillermo Haro Observatory. Observational data allow us to conclude that this object is a pair of interacting galaxies, a LINER and a HII galaxy, at $z=0.093$.

  18. Brightest Cluster Galaxies in the Extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    E-Print Network [OSTI]

    Kale, Ruta; Cassano, Rossella; Giacintucci, Simona; Bardelli, sandro; Dallacasa, Daniele; Zucca, Elena

    2015-01-01T23:59:59.000Z

    Brightest Cluster Galaxies (BCGs) show exceptional properties over the whole electromagnetic spectrum. Their special location at the centres of galaxy clusters raises the question of the role of the environment on their radio properties. To decouple the effect of the galaxy mass and of the environment in their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS). We obtained a statistical sample of 59 BCGs, which was divided into two classes, depending on the dynamical state of the host cluster, i.e. merging (M) and relaxed (R). Among the 59 BCGs, 28 are radio-loud, and 31 are radio--quiet. The radio-loud sources are located favourably located in relaxed clusters (71\\%), while the reverse is true for the radio-quiet BCGs, mostly located in merging systems (81\\%). The fraction...

  19. First detections of 610 MHz radio emission from hot magnetic stars

    E-Print Network [OSTI]

    Chandra, P; Sundqvist, J O; Oberoi, D; Grunhut, J H; ud-Doula, A; Petit, V; Cohen, D H; Oksala, M E; David-Uraz, A

    2015-01-01T23:59:59.000Z

    We have carried out a study of radio emission from a small sample of magnetic O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of investigating their magnetospheres at low frequencies. These are the lowest frequency radio measurements ever obtained of hot magnetic stars. The observations were taken at random rotational phases in the 1390 and the 610 MHz bands. Out of the 8 stars, we detect five B-type stars in both the 1390 and the 610 MHz bands. The O-type stars were observed only in the 1390 MHz band, and no detections were obtained. We explain this result as a consequence of free-free absorption by the free-flowing stellar wind exterior to the closed magnetosphere. We also study the variability of individual stars. One star - HD 133880 - exhibits remarkably strong and rapid variability of its low frequency flux density. We discuss the possibility of this emission being coherent emission as reported for CU Vir by Trigilio et al. (2000).

  20. Microfabricated ion frequency standard

    SciTech Connect (OSTI)

    Schwindt, Peter (Albuquerque, NM); Biedermann, Grant (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Stick, Daniel L. (Albuquerque, NM); Serkland, Darwin K. (Albuquerque, NM); Olsson, III, Roy H. (Albuquerque, NM)

    2010-12-28T23:59:59.000Z

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  1. Continuum Radio Emission and Diagnostics

    E-Print Network [OSTI]

    White, Stephen

    and inversely proportional to the square of frequency and to temperature to the power 1.5. It is therefore discusses incoher­ ent emission from thermal plasma in the non­flaring so­ lar atmosphere; other relevant. The opacity of this mecha­ nism is proportional to the product of the electron and ion charge densities

  2. Identifying the source of perytons at the Parkes radio telescope

    E-Print Network [OSTI]

    Petroff, E; Barr, E D; Reynolds, J E; Sarkissian, J; Edwards, P G; Stevens, J; Brem, C; Jameson, A; Burke-Spolaor, S; Johnston, S; Bhat, N D R; Chandra, P; Kudale, S; Bhandari, S

    2015-01-01T23:59:59.000Z

    "Perytons" are millisecond-duration transients of terrestrial origin, whose frequency-swept emission mimics the dispersion of an astrophysical pulse that has propagated through tenuous cold plasma. In fact, their similarity to FRB 010724 had previously cast a shadow over the interpretation of "fast radio bursts," which otherwise appear to be of extragalactic origin. Until now, the physical origin of the dispersion-mimicking perytons had remained a mystery. We have identified strong out-of-band emission at 2.3--2.5 GHz associated with several peryton events. Subsequent tests revealed that a peryton can be generated at 1.4 GHz when a microwave oven door is opened prematurely and the telescope is at an appropriate relative angle. Radio emission escaping from microwave ovens during the magnetron shut-down phase neatly explain all of the observed properties of the peryton signals. Now that the peryton source has been identified, we furthermore demonstrate that the microwaves on site could not have caused FRB 01072...

  3. Optimization of radio astronomical observations using Allan variance measurements

    E-Print Network [OSTI]

    R. Schieder; C. Kramer

    2001-05-04T23:59:59.000Z

    Stability tests based on the Allan variance method have become a standard procedure for the evaluation of the quality of radio-astronomical instrumentation. They are very simple and simulate the situation when detecting weak signals buried in large noise fluctuations. For the special conditions during observations an outline of the basic properties of the Allan variance is given, and some guidelines how to interpret the results of the measurements are presented. Based on a rather simple mathematical treatment clear rules for observations in ``Position-Switch'', ``Beam-'' or ``Frequency-Switch'', ``On-The-Fly-'' and ``Raster-Mapping'' mode are derived. Also, a simple ``rule of the thumb'' for an estimate of the optimum timing for the observations is found. The analysis leads to a conclusive strategy how to plan radio-astronomical observations. Particularly for air- and space-borne observatories it is very important to determine, how the extremely precious observing time can be used with maximum efficiency. The analysis should help to increase the scientific yield in such cases significantly.

  4. Energy Efficient Transmissions In MIMO Cognitive Radio Networks

    E-Print Network [OSTI]

    Huang, Jianwei

    Energy Efficient Transmissions In MIMO Cognitive Radio Networks Liqun Fu The Institute of Network@ie.cuhk.edu.hk Abstract-In this paper, we consider energy efficient transmis sions for MIMO cognitive radio networks. Index Terms-Cognitive radio networks, MIMO, Energy efficiency. I. INTRODUCTION Cognitive radio, which

  5. RADIO PROCEDURES DURING NORMAL OPERATING CONDITIONS CALLING AND COMMUNICATING TECHNIQUES

    E-Print Network [OSTI]

    Brody, James P.

    RADIO PROCEDURES DURING NORMAL OPERATING CONDITIONS CALLING AND COMMUNICATING TECHNIQUES The secret are going to say. Many people with radios have a tendency to talk and/or repeat too much. Say what you need until it is second nature. Practicing proper day-to-day radio procedures will make emergency radio

  6. Leveraging Multiple Heterogeneous Radios for Energy-efficient Routing

    E-Print Network [OSTI]

    Kravets, Robin

    /low- rate radio) and presented a dual-radio communication protocol that manages the transitions of the high-power/n. To calculate the anticipated delay, each node mon- Power Source Dual Power Dual Radio MonitorPower Meter Figure efficiency than these lower-power radios due to their higher bit rates, the larger idle costs make them less

  7. Radio Frequency and Microwave Hazards Radio frequency (rf) and microwaves occur within the range 10 kHz to 300,000 MHz and are

    E-Print Network [OSTI]

    Shull, Kenneth R.

    kHz to 300,000 MHz and are used in rf ovens and furnaces, induction heaters, and microwave ovens. Microwave ovens are increasingly being used in laboratories for organic synthesis and digestion of analytical samples. Only microwave ovens designed for laboratory or industrial use should be used

  8. LOOKING FOR A PULSE: A SEARCH FOR ROTATIONALLY MODULATED RADIO EMISSION FROM THE HOT JUPITER, {tau} BOOeTIS b

    SciTech Connect (OSTI)

    Hallinan, G.; Bourke, S. [Cahill Center for Astrophysics, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125 (United States)] [Cahill Center for Astrophysics, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125 (United States); Sirothia, S. K.; Ishwara-Chandra, C. H. [National Centre for Radio Astrophysics, TIFR, Post Bag 3, Pune University Campus, Pune 411007 (India)] [National Centre for Radio Astrophysics, TIFR, Post Bag 3, Pune University Campus, Pune 411007 (India); Antonova, A. [Department of Astronomy, St. Kliment Ohridski University of Sofia, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria)] [Department of Astronomy, St. Kliment Ohridski University of Sofia, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria); Doyle, J. G. [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom)] [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom); Hartman, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)] [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Golden, A. [Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461 (United States)] [Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461 (United States)

    2013-01-01T23:59:59.000Z

    Hot Jupiters have been proposed as a likely population of low-frequency radio sources due to electron cyclotron maser emission of similar nature to that detected from the auroral regions of magnetized solar system planets. Such emission will likely be confined to specific ranges of orbital/rotational phase due to a narrowly beamed radiation pattern. We report on GMRT 150 MHz radio observations of the hot Jupiter {tau} Booetis b, consisting of 40 hr carefully scheduled to maximize coverage of the planet's 79.5 hr orbital/rotational period in an effort to detect such rotationally modulated emission. The resulting image is the deepest yet published at these frequencies and leads to a 3{sigma} upper limit on the flux density from the planet of 1.2 mJy, two orders of magnitude lower than predictions derived from scaling laws based on solar system planetary radio emission. This represents the most stringent upper limits for both quiescent and rotationally modulated radio emission from a hot Jupiter yet achieved and suggests that either (1) the magnetic dipole moment of {tau} Booetis b is insufficient to generate the surface field strengths of >50 G required for detection at 150 MHz or (2) Earth lies outside the beaming pattern of the radio emission from the planet.

  9. The nature of the optical---radio correlations for powerful radio galaxies

    E-Print Network [OSTI]

    C. N. Tadhunter; R. Morganti; A. Robinson; R. Dickson; M. Villar-Martin; R. A. E. Fosbury

    1998-07-23T23:59:59.000Z

    The nature of the optical--radio correlations for powerful radio galaxies is investigated using spectroscopic observations of a complete sample of southern 2Jy radio sources. In line with previous work, we find that significant correlations exist between the luminosities of the [OIII]5007, [OII]3727 and Hbeta emission lines and the radio luminosity. However, our observations are not easily reconciled with the idea that these correlations are caused by the increase in the power of the photoionizing quasar as the jet power increases, with average ISM properties not changing appreciably with redshift or radio power: not only do we find that the scatter in the L_[OIII] vs. L_radio correlation is significantly larger than in L_[OII]} vs. L_radio and L_Hbeta vs. L_radio correlations, but the ionization state deduced from the emission lines does not increase with radio power as predicted by the simple, constant ISM, photionization model. We conclude that: (a) there exists a considerable range in the quasar ionizing luminosity at a given redshift; and (b) that the mean density of the emission line clouds is larger in the high redshift/high power radio sources. The latter density enhancement may either be a consequence of the increased importance of jet-cloud interactions or, alternatively, due to a higher pressure in the confining hot ISM, in the high redshift objects. Deep spectra show that many of the sources in our sample are broad line radio galaxies (BLRG). The fact that the BLRG are observed out the redshift limit of the survey, overlapping in redshift with the quasars, argues against the idea that BLRG are simply the low radio power counterparts of high power, high redshift quasars.

  10. Design and implementation of a frequency synthesizer for an IEEE 802.15.4/Zigbee transceiver 

    E-Print Network [OSTI]

    Srinivasan, Rangakrishnan

    2007-09-17T23:59:59.000Z

    The frequency synthesizer, which performs the main role of carrier generation for the down-conversion/up-conversion operations, is a key building block in radio transceiver front-ends. The design of a synthesizer for a 2.4 GHz IEEE 802.15.4/Zigbee...

  11. Progress on the Frequency Agile Solar Radiotelescope T.S. Bastian

    E-Print Network [OSTI]

    : coronal magnetography, solar ares and particle acceleration, drivers of space weather, and the thermal the thermal structure and dynamics of the solar chromosphere. In addition to its priority mission as a basicProgress on the Frequency Agile Solar Radiotelescope T.S. Bastian National Radio Astronomy

  12. Radio Spectrum and Distance of the SNR HB9

    E-Print Network [OSTI]

    D. A. Leahy; W. W. Tian

    2006-10-26T23:59:59.000Z

    New images are presented of the supernova remnant (SNR) HB9 based on 408 MHz and 1420 MHz continuum emission and HI-line emission data of the Canadian Galactic Plane Survey (CGPS) by the Dominion Radio Astrophysical Observatory (DRAO). Two methods of spectral index analysis for HB9 are presented and compared: one removes compact sources at both frequencies but is limited to the resolution of the 408 MHz image; the other removes compact sources only in the 1420 MHz image so is effective at higher spatial resolution. The second allows more detailed spectral index variation studies than the first. The two T-T plot methods and new integrated flux densities give spectral index (S_{\

  13. Radio Wavelength Observatories within the Exploration Architecture

    E-Print Network [OSTI]

    J. Lazio; R. J. Macdowall; J. Burns; L. Demaio; D. L. Jones; K. W. Weiler

    2007-01-26T23:59:59.000Z

    Observations at radio wavelengths address key problems in astrophysics, astrobiology, and lunar structure including the first light in the Universe (the Epoch of Reionization), the presence of magnetic fields around extrasolar planets, particle acceleration mechanisms, and the structure of the lunar ionosphere. Moreover, achieving the performance needed to address these scientific questions demands observations at wavelengths longer than those that penetrate the Earth's ionosphere, observations in extremely "radio quiet" locations such as the Moon's far side, or both. We describe a series of lunar-based radio wavelength interferometers of increasing capability. The Radio Observatory for Lunar Sortie Science (ROLSS) is an array designed to be deployed during the first lunar sorties (or even before via robotic rovers) and addressing particle acceleration and the lunar ionosphere. Future arrays would be larger, more capable, and deployed as experience is gained in working on the lunar surface.

  14. An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays

    E-Print Network [OSTI]

    Zbigniew Szadkowski for the Pierre Auger Collaboration

    2014-06-04T23:59:59.000Z

    Experiments that observe coherent radio emission from extensive air showers induced by ultra-high energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100% up time as e.g. surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g. the Pierre Auger Observatory) as another type of air shower detector in addition to the fluorescence detectors, which operate with only ~10% of duty in dark nights. The radio signals from air showers are caused by the coherent emission due to geomagnetic radiation and charge excess processes. Currently used self-triggers in radio detectors often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data requires a significant man-power for the off-line analysis. An improvement of the trigger efficiency becomes a relevant factor. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for an optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not origin from cosmic ray showers but can be human-made contaminations. The engine of the wavelet analysis can be implemented into the modern powerful FPGA and can remove suspicious events on-line to reduce the trigger rate.

  15. UC Irvine 800MHz Trunked Radio System Revised 08/16/96 UCI RADIO USE AND PROCEDURES

    E-Print Network [OSTI]

    Brody, James P.

    and/or sound effects over the radio. This activity violates UC and Federal Communications Commission communications are in progress on other talk groups and your unnecessary transmission may delay another radio radio identifier or radio call ]__ , reporting an emergency. " The Communications Center dispatcher

  16. A radio-map of the colliding winds in the very massive binary system HD 93129A

    E-Print Network [OSTI]

    Benaglia, Paula; Moldon, Javier; Nelan, Ed; De Becker, Michael; Dougherty, Sean M; Koribalski, Baerbel

    2015-01-01T23:59:59.000Z

    Radio observations are an effective tool to discover particle acceleration regions in colliding-wind binaries, through detection of synchrotron radiation; these regions are natural laboratories for the study of relativistic particles. Wind-collision region (WCR) models can reproduce the radio continuum spectra of massive binaries that contain both thermal and non-thermal radio emission; however, key constraints for models come from high-resolution imaging. Only five WCRs have been resolved to date at radio frequencies at milliarcsec (mas) angular scales. The source HD 93129A, prototype of the very few known O2 I stars, is a promising target for study: recently, a second massive, early-type star about 50 mas away was discovered, and a non-thermal radio source detected in the region. Preliminary long-baseline array data suggest that a significant fraction of the radio emission from the system comes from a putative WCR. We sought evidence that HD 93129A is a massive binary system with colliding stellar winds tha...

  17. Radio signals of particle dark matter

    E-Print Network [OSTI]

    Marco Regis

    2011-12-08T23:59:59.000Z

    In most of particle dark matter (DM) models, the DM candidate injects sizable fluxes of high-energy electrons and positrons through its annihilations or decays. Emitted in regions with magnetic field, they in turn give raise to a synchrotron radiation, which typically covers radio and infrared bands. We discuss the possibility of detecting signatures of Galactic and extra-galactic DM in the total intensity and small-scale anisotropies of the radio background.

  18. Low Luminosity Radio Loud Active Galactic Nuclei

    E-Print Network [OSTI]

    G. Giovannini; M. Giroletti

    2007-08-30T23:59:59.000Z

    I review observational properties of low power radio loud AGN. High resolution VLBI observations allow the estimate of the jet velocity and orientation with respect to the line of sight and the determination of the Doppler factor. These data reveal rich structures, including two-sided jets and secondary components. New results on 1144+35, a giant radio source with superluminal motion are shown in detail.

  19. Spectral Energy Distribution of Radio Sources in Nearby Clusters of Galaxies: Implications for Sunyaev-Zel'dovich Effect Surveys

    E-Print Network [OSTI]

    Yen-Ting Lin; Bruce Partridge; J. C. Pober; Khadija El Bouchefry; Sarah Burke; Jonathan Klein; Joseph Coish; Kevin Huffenberger

    2009-04-04T23:59:59.000Z

    To explore the high frequency radio spectra of galaxies in clusters, we used NRAO's Very Large Array at four frequencies, 4.9-43 GHz, to observe 139 galaxies in low redshift (z22 GHz, implying a higher flux than would be expected from an extrapolation of the lower frequency flux measurements. Our results quantify the need for careful source subtraction in increasingly sensitive measurements of the Sunyaev-Zel'dovich effect in clusters of galaxies (as currently being conducted by, for instance, the Atacama Cosmology Telescope and South Pole Telescope groups).

  20. Through-the-earth radio

    DOE Patents [OSTI]

    Reagor, David; Vasquez-Dominguez, Jose

    2006-12-12T23:59:59.000Z

    A through-the-earth communication system that includes a digital signal input device; a transmitter operating at a predetermined frequency sufficiently low to effectively penetrate useful distances through-the earth; a data compression circuit that is connected to an encoding processor; an amplifier that receives encoded output from the encoding processor for amplifying the output and transmitting the data to an antenna; and a receiver with an antenna, a band pass filter, a decoding processor, and a data decompressor.

  1. Graphene Frequency Multipliers

    E-Print Network [OSTI]

    Wang, Han

    In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...

  2. Variable Frequency Pump Drives

    E-Print Network [OSTI]

    Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

    . In a conventional pump and driver arrangement (for example, a centrifugal pump coupled to an AC induction motor'with no speed control provision), the motor runs at. a constant speed, which is determined by the incoming line frequency, and the pump... when it is needed. LONG RANGE DESIGN TRENDS The growing use of variable-frequency electric motor drives will permit the integration of 60 and 50 cycle pump lines. One important concern for future improvements is the growing possibility...

  3. THE DOUBLE PULSAR ECLIPSES. I. PHENOMENOLOGY AND MULTI-FREQUENCY ANALYSIS

    SciTech Connect (OSTI)

    Breton, R. P. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Kaspi, V. M. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Lyutikov, M. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Kramer, M. [Max Planck Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Ferdman, R. D. [University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester, M13 9PL (United Kingdom); Camilo, F. [Columbia University, New York, NY 10027 (United States); Possenti, A., E-mail: breton@astro.utoronto.ca [INAF-Osservatorio Astronomico di Cagliari, Poggio dei Pini, strada 54, I-09012 Capoterra (Italy)

    2012-03-10T23:59:59.000Z

    The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise around conjunction when the radio waves emitted by pulsar A are absorbed as they propagate through the magnetosphere of its companion pulsar B. These eclipses offer a unique opportunity to directly probe the magnetospheric structure and the plasma properties of pulsar B. We have performed a comprehensive analysis of the eclipse phenomenology using multi-frequency radio observations obtained with the Green Bank Telescope. We have characterized the periodic flux modulations previously discovered at 820 MHz by McLaughlin et al. and investigated the radio frequency dependence of the duration and depth of the eclipses. Based on their weak radio frequency evolution, we conclude that the plasma in pulsar B's magnetosphere requires a large multiplicity factor ({approx}10{sup 5}). We also found that, as expected, flux modulations are present at all radio frequencies in which eclipses can be detected. Their complex behavior is consistent with the confinement of the absorbing plasma in the dipolar magnetic field of pulsar B as suggested by Lyutikov and Thompson and such a geometric connection explains that the observed periodicity is harmonically related to pulsar B's spin frequency. We observe that the eclipses require a sharp transition region beyond which the plasma density drops off abruptly. Such a region defines a plasmasphere that would be well inside the magnetospheric boundary of an undisturbed pulsar. It is also two times smaller than the expected standoff radius calculated using the balance of the wind pressure from pulsar A and the nominally estimated magnetic pressure of pulsar B.

  4. Nanoparticles designed from low pressure plasmas as identification tool for astrophysical observations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    interstellar media. The particles were polymerised in a low pressure capacitively coupled radio-frequency molecule production and reprocesses UV and optical radiation. The C-H stretch vibration of aliphatic coupled the radiofrequency discharge in argon/acetylene mixtures [Kovacevic submitted]. The particles

  5. A Combined EIS-NVSS Survey Of Radio Sources II: Infrared imaging and the K-z relation

    E-Print Network [OSTI]

    M. H. Brookes; P. N. Best; R. Rengelink; H. J. A. Rottgering

    2006-03-27T23:59:59.000Z

    The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4 GHz radio survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which is a 3 by 2 square degree field centred on 09 51 36.0 -21 00 00 (J2000). This paper presents K-band imaging of 142 of the 150 CENSORS sources. The primary motivation for beginning infrared imaging of the sample was to identify the host galaxies of the ~30% of sources for which the EIS I-band imaging failed to produce a likely candidate. In addition, K-band magnitudes allow photometric redshift estimation and I - K colours aid the identification of host galaxies (which are typically old, red ellipticals). Of the sources observed in the I and K-bands, four remain undetected, possibly indicating high redshifts for the host galaxies, and eight involve complicated radio structures, or several candidate host galaxies, which have yet to be resolved. Thus, the host galaxy identifications are brought to 92% completeness. In conjunction with spectroscopic observations, the K-band magnitudes have been aperture corrected and used to establish a K-z relation for the CENSORS radio galaxies. This relation is of interest because of its variation, at z > 1, between radio surveys of different flux-density limit. Establishing this relation for CENSORS may shed light on the origin of this variation and will allow an appropriate K-z redshift estimator for any CENSORS source which remains without a spectroscopic redshift. It is shown that whilst the K-z relation for CENSORS is fainter than that of 3CRR at all redshifts, it agrees well with that of 7C over all redshifts studied.

  6. Radio broadcasting and the politics of mass culture in transwar Japan

    E-Print Network [OSTI]

    Jung, Ji Hee

    2010-01-01T23:59:59.000Z

    Press, Cox, Jim. The Great Radio Audience ParticipationSusan. Listening In: Radio and the American Imagination. NewCalling: Japanese Overseas Radio Broadcasting 1937- 1945.

  7. Fully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased-Array Receiver in CMOS

    E-Print Network [OSTI]

    Hajimiri, Ali

    control, phase locked loops, phase noise, phased arrays, radio receivers I. INTRODUCTION Very large-scale phased-arrays covering a wide range of frequencies can provide exciting new opportunities for increasedFully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased

  8. Radio-Excess IRAS Galaxies: IV. Optical Spectroscopy

    E-Print Network [OSTI]

    Catherine L. Buchanan; Peter J. McGregor; Geoffrey V. Bicknell; Michael A. Dopita

    2006-04-21T23:59:59.000Z

    This is the fourth in our series of papers investigating radio-excess galaxies, which have radio emission associated with an active nucleus but which do not fit into the traditional categories of either radio-loud or radio-quiet active galaxies. In this paper, we present optical spectra of our sample of FIR-luminous radio-excess galaxies. Optical emission line diagnostics are used to determine the dominant source of the ionizing radiation. We find that radio excess is an excellent indicator of the presence of an active nucleus: the radio-excess sample contains a much higher fraction of AGN than samples selected on FIR luminosity alone, or using other criteria such as warm FIR colors. Several objects have ambiguous classifications and are likely to be composite objects with mixed excitation. The type of optical spectrum appears to be associated with the radio-loudness: radio-loud objects may be more `pure' AGN than radio-intermediate objects. We find strong evidence for interaction between the radio plasma and the surrounding gas. The jet energy fluxes of the radio-excess objects, inferred from the [O III] luminosities, are lower than in powerful radio sources, consistent with our previous results. We conclude that the jets of radio-intermediate sources are intrinsically weaker than those in sources with more powerful radio emission. A significant fraction of the sample spectra show post-starburst stellar continuum, with A-star absorption lines, consistent with the large fraction of merging or disturbed host galaxies in the sample. The ages of the radio sources are significantly less than those of A stars indicating that, if the radio sources are associated with merging activity, there is a delay between the interaction and the initiation of the radio activity. (Abridged.)

  9. Portable Microwave Frequency Dissemination in Free Space and Implications on Ground-Satellite Synchronization

    E-Print Network [OSTI]

    Wang, Bo; Bai, Yu; Yuan, Yibo; Gao, Chao; Wang, Lijun

    2015-01-01T23:59:59.000Z

    Frequency dissemination and synchronization in free space plays an important role in global navigation satellite system (GNSS), radio astronomy and synthetic aperture radar (SAR). In this paper, we demonstrate a portable radio frequency (RF) dissemination scheme via free space using microwave antennas. The setup has a good environment adaptability and high dissemination stability. The frequency signal is disseminated at different distances ranging from 10 to 640 m with a fixed 10 Hz locking bandwidth, and the scaling law of dissemination stability on distance and averaging time is discussed. The preliminary extrapolation shows that the dissemination stability may reach $1\\times10^{-12}/s$ in ground-to-satellite synchronization, which far exceeds all present methods, and is worthy for further study.

  10. Seyfert galaxies: Nuclear Radio Structure and Unification

    E-Print Network [OSTI]

    Lal, Dharam V; Gabuzda, Denise

    2011-01-01T23:59:59.000Z

    A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nuclei (AGN) power and host galaxy properties is presented to test the predictions of the unified scheme hypothesis. Our sample sources have core flux densities greater than 8 mJy at 5 GHz on arcsec-scales due to the feasibility requirements. These simultaneous pc-scale and kpc-scale radio observations reveal (i) that Seyfert 1 and Seyfert 2 galaxies have equal tendency to show compact radio structures on mas-scales, (ii) the distributions of pc-scale and kpc-scale radio luminosities are similar for both Seyfert 1 and Seyfert 2 galaxies, (iii) no evidence for relativistic beaming in Seyfert galaxies, (iv) similar distributions of source spectral indices in spite of the fact that Seyferts show nuclear radio flux density variations, and (v) the distributions of projected linear size for Seyfert 1 and Seyfert 2 galaxies are not significantly d...

  11. Extended emission around GPS radio sources

    E-Print Network [OSTI]

    C. Stanghellini; C. P. O'Dea; D. Dallacasa; P. Cassaro; S. A. Baum; R. Fanti; C. Fanti

    2005-07-21T23:59:59.000Z

    Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS) radio sources is discussed. Evidence for extended emission which is related to the GPS source is found in 6 objects out of 33. Three objects are associated with quasars with core-jet pc-scale morphology, and three are identified with galaxies with symmetric (CSO) radio morphology. We conclude that the core-jet GPS quasars are likely to be beamed objects with a continuous supply of energy from the core to the kpc scale. It is also possible that low surface brightness extended radio emission is present in other GPS quasars but the emission is below our detection limit due to the high redshifts of the objects. On the other hand, the CSO/galaxies with extended large scale emission may be rejuvenated sources where the extended emission is the relic of previous activity. In general, the presence of large scale emission associated with GPS galaxies is uncommon, suggesting that in the context of the recurrent activity model, the time scale between subsequent bursts is in general longer than the radiative lifetime of the radio emission from the earlier activity.

  12. Solar Radio Bursts with Spectral Fine Structures in Preflares

    E-Print Network [OSTI]

    Zhang, Yin; Karlický, Marian; Mészárosová, Hana; Huang, Jing; Tan, Chengming; Simões, Paulo

    2014-01-01T23:59:59.000Z

    A good observation of preflare activities is important for us to understand the origin and triggering mechanism of solar flares, and to predict the occurrence of solar flares. This work presents the characteristics of microwave spectral fine structures as preflare activities of four solar flares observed by Ond\\v{r}ejov radio spectrograph in the frequency range of 0.8--2.0 GHz. We found that these microwave bursts which occurred 1--4 minutes before the onset of flares have spectral fine structures with relatively weak intensities and very short timescales. They include microwave quasi-periodic pulsations (QPP) with very short period of 0.1-0.3 s and dot bursts with millisecond timescales and narrow frequency bandwidths. Accompanying these microwave bursts, there are filament motions, plasma ejection or loop brightening on the EUV imaging observations and non-thermal hard X-ray emission enhancements observed by RHESSI. These facts may reveal certain independent non-thermal energy releasing processes and partic...

  13. Improved spacecraft radio science using an on-board atomic clock: Application to gravitational wave searches

    SciTech Connect (OSTI)

    Tinto, Massimo; Dick, George J.; Prestage, John D.; Armstrong, J. W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    2009-05-15T23:59:59.000Z

    Recent advances in space-qualified atomic clocks (low-mass, low power-consumption, frequency stability comparable to that of ground-based clocks) can enable interplanetary spacecraft radio science experiments at unprecedented Doppler sensitivities. The addition of an on-board digital receiver would allow the up- and down-link Doppler frequencies to be measured separately. Such separate, high-quality measurements allow optimal data combinations that suppress the currently leading noise sources: phase scintillation noise from the Earth's atmosphere and Doppler noise caused by mechanical vibrations of the ground antenna. Here we provide a general expression for the optimal combination of ground and on-board Doppler data and compute the sensitivity such a system would have to low-frequency gravitational waves (GWs). Assuming a plasma scintillation noise calibration comparable to that already demonstrated with the multilink CASSINI radio system, the space-clock/digital-receiver instrumentation enhancements would give GW strain sensitivity of 3.7x10{sup -14} Hz{sup -1/2} for randomly polarized, monochromatic GW signals isotropically distributed over the celestial sphere, over a two-decade ({approx}0.0001-0.01 Hz) region of the low-frequency band. This is about an order of magnitude better than currently achieved with traditional two-way coherent Doppler experiments. The utility of optimally combining simultaneous up- and down-link observations is not limited to GW searches. The Doppler tracking technique discussed here could be performed at minimal incremental cost to improve also other radio science experiments (i.e., tests of relativistic gravity, planetary and satellite gravity field measurements, atmospheric and ring occultations) on future interplanetary missions.

  14. Reconstruction of the energy and depth of maximum of cosmic-ray air-showers from LOPES radio measurements

    E-Print Network [OSTI]

    W. D. Apel; J. C. Arteaga-Velazquez; L. Bähren; K. Bekk; M. Bertaina; P. L. Biermann; J. Blümer; H. Bozdog; I. M. Brancus; E. Cantoni; A. Chiavassa; K. Daumiller; V. de Souza; F. Di Pierro; P. Doll; R. Engel; H. Falcke; B. Fuchs; D. Fuhrmann; H. Gemmeke; C. Grupen; A. Haungs; D. Heck; J. R. Hörandel; A. Horneffer; D. Huber; T. Huege; P. G. Isar; K. -H. Kampert; D. Kang; O. Krömer; J. Kuijpers; K. Link; P. ?uczak; M. Ludwig; H. J. Mathes; M. Melissas; C. Morello; J. Oehlschläger; N. Palmieri; T. Pierog; J. Rautenberg; H. Rebel; M. Roth; C. Rühle; A. Saftoiu; H. Schieler; A. Schmidt; F. G. Schröder; O. Sima; G. Toma; G. C. Trinchero; A. Weindl; J. Wochele; J. Zabierowski; J. A. Zensus

    2014-08-11T23:59:59.000Z

    LOPES is a digital radio interferometer located at Karlsruhe Institute of Technology (KIT), Germany, which measures radio emission from extensive air showers at MHz frequencies in coincidence with KASCADE-Grande. In this article, we explore a method (slope method) which leverages the slope of the measured radio lateral distribution to reconstruct crucial attributes of primary cosmic rays. First, we present an investigation of the method on the basis of pure simulations. Second, we directly apply the slope method to LOPES measurements. Applying the slope method to simulations, we obtain uncertainties on the reconstruction of energy and depth of shower maximum Xmax of 13% and 50 g/cm^2, respectively. Applying it to LOPES measurements, we are able to reconstruct energy and Xmax of individual events with upper limits on the precision of 20-25% for the primary energy and 95 g/cm^2 for Xmax, despite strong human-made noise at the LOPES site.

  15. Marine asset security and tracking (MAST) system

    DOE Patents [OSTI]

    Hanson, Gregory Richard (Clinton, TN); Smith, Stephen Fulton (Loudon, TN); Moore, Michael Roy (Corryton, TN); Dobson, Eric Lesley (Charleston, SC); Blair, Jeffrey Scott (Charleston, SC); Duncan, Christopher Allen (Marietta, GA); Lenarduzzi, Roberto (Knoxville, TN)

    2008-07-01T23:59:59.000Z

    Methods and apparatus are described for marine asset security and tracking (MAST). A method includes transmitting identification data, location data and environmental state sensor data from a radio frequency tag. An apparatus includes a radio frequency tag that transmits identification data, location data and environmental state sensor data. Another method includes transmitting identification data and location data from a radio frequency tag using hybrid spread-spectrum modulation. Another apparatus includes a radio frequency tag that transmits both identification data and location data using hybrid spread-spectrum modulation.

  16. Sounds energetic: the radio producer's energy minibook

    SciTech Connect (OSTI)

    Not Available

    1980-12-01T23:59:59.000Z

    The Minibook will be expanded into the final Radio Producer's Energy Sourcebook. Radio producers and broadcasters are asked to contribute ideas for presenting energy knowledge to the public and to be included in the Sourcebook. Chapter One presents a case study suggesting programming and promotion ideas and sample scripts for a radio campaign that revolves around no-cost or low-cost steps listeners can take to increase their home energy efficiency and save money. A variety of other energy topics and suggestions on ways to approach them are addressed in Chapter Two. Chapter Three contains energy directories for Baltimore, Philadelphia, Pittsburg, and Washington, DC. The directories will be expanded in the Sourcebook and will consist of a selection of local public and private sector energy-related organizations and list local experts and organizations and the best Federal, state, and local government programs that can provide consumers and citizens groups with information, technical assistance, and financial support. (MCW)

  17. Radio galaxies in the 2SLAQ Luminous Red Galaxy survey: II. The stellar populations of radio-loud and radio-quiet LRGs

    E-Print Network [OSTI]

    Helen M. Johnston; Elaine M. Sadler; Russell Cannon; Scott M. Croom; Nicholas P. Ross; Donald P. Schneider

    2007-11-21T23:59:59.000Z

    We present an analysis of the optical spectra of a volume-limited sample of 375 radio galaxies at redshift 0.4radio-quiet sources from the same survey, we also investigate the effect on the galaxy of the presence of an active nucleus. The composite spectra, binned by redshift and radio luminosity, all require two components to describe them, which we interpret as an old and a younger population. We found no evolution with redshift of the age of the younger population in radio galaxies, nor were they different from the radio-quiet comparison sample. Similarly, there is no correlation with radio power, with the exception that the most powerful radio sources (P(1.4) > 10^26 W/Hz) have younger stars and stronger emission lines than the less powerful sources. This suggests that we have located the threshold in radio power where strong emission lines "switch on", at radio powers of around 10^26 W/Hz. Except for the very powerful radio galaxies, the presence of a currently-active radio AGN does not appear to be correlated with any change in the observed stellar population of a luminous red galaxy at z~0.5.

  18. Radio-tracking reveals that lesser horseshoe bats (Rhinolophus hipposideros) forage in woodland

    E-Print Network [OSTI]

    Richner, Heinz

    Radio-tracking reveals that lesser horseshoe bats (Rhinolophus hipposideros) forage in woodland±8 g) precluded the use of radio-telemetry because commercially available radio-transmitters exceeded 10% of its body mass. In this study, radio- transmitters weighing

  19. GPS radio occultation with CHAMP Jens Wickert, Georg Beyerle, Torsten Schmidt, Christian Marquardt, Rolf

    E-Print Network [OSTI]

    GPS radio occultation with CHAMP Jens Wickert, Georg Beyerle, Torsten Schmidt, Christian Marquardt Positioning System) radio occultation experiment onboard the German CHAMP (CHAllenging Minisatellite Payload sensing of Earth's atmosphere, GPS radio occulta- tion 1 Introduction The CHAMP GPS radio occultation

  20. Coherent Transition Radiation in Askaryan radio detectors

    E-Print Network [OSTI]

    de Vries, Krijn D; van Eijndhoven, Nick; Meures, Thomas; O'Murchadha, Aongus; Scholten, Olaf

    2015-01-01T23:59:59.000Z

    We discuss the coherent transition radiation emitted by a macroscopic bunch of particles with a net charge traversing the boundary of two different media. The obtained expression is compared to the emission from a relativistically moving steady charge, as well the emission from a time-varying charge or current. As a first application, we discuss the transition radiation from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux.