Sample records for radio frequency rf

  1. 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...

  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. 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.

  4. Pulse-Density Modulation for RF Applications: The Radio-Frequency Power Amplifier (RF PA)

    E-Print Network [OSTI]

    Sanders, Seth

    . This enables complex digital processing and control of RF switching waveforms. Trends in processing speed demonstrates, techniques previously used for audio amplifiers, motor control, and power conversion may now generations of CMOS technology. We implement digital control of the carrier amplitude using pulse

  5. Parasitic Characterization of RadioFrequency (RF) Circuits Using MixedMode Simulation

    E-Print Network [OSTI]

    Dutton, Robert W.

    . Introduction For monolithic microwave and RF integrated cir­ cuit applications, accurate modeling of parasitic can vary depending upon the fitting method and the start­ ing guess. In the case of analytical parameter fit­ ting, additional test structures are usually required to consider de­embedding the S

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    DOE Patents [OSTI]

    Norem, James H.; Pellin, Michael J.

    2013-06-11T23:59:59.000Z

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  11. 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.

  12. 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 ...

  13. 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

  14. 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

  15. 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...

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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 ...

  3. Extremely high frequency RF effects on electronics.

    SciTech Connect (OSTI)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01T23:59:59.000Z

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  4. 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

  5. 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

  6. 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 ...

  7. 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

  8. 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

  9. Frequency and amplitude control for an experimental linac rf drive

    E-Print Network [OSTI]

    Atre, Mahesh Purushottam

    1992-01-01T23:59:59.000Z

    uses a RFQ accelerator/buncher to accelerate a beam of II ions. The 500 keV, 10 mA beam will require approximately 100 kW (peak) rf power at 473 MHz [2]. The basic layout of the linac system is illustrated in Fig. 1. The rf power source uses...-rod structure resonant at 473 MHz. ION SOURCE RF QUADRUPOLE BEAM HIGH POWER RF AMP AMPL CONTROL LOW POWER RF AMP OSC FREQ CONTROL SYSTEM Figure 1. The Experimental Linac System The oscillator uses a phase-locked loop for frequency control...

  10. 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...

  11. 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.

  12. Robust Diamond-Based RF Switch Yields Enhanced Communication...

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

    Robust Diamond-Based RF Switch Yields Enhanced Communication Capabilities Technology available for licesning: A radio frequency (RF) microelectromechanical system (MEMS) switch...

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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...

  20. 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.

  1. Introduction Final Cooling Channel -High Frequency RF

    E-Print Network [OSTI]

    McDonald, Kirk

    algorithms integration with G4BL on NERSC Integration of twiss calculations with G4BL & Optimization codes Calculation of twiss function inside absorber+RF 0 5 10 15 20 25 0 1 2 3 4 5 6 7 8 9 10 P[GeV/c] z [m] Bz P=0V/c P=0.127 GeV/c In order to match for the field flip one needs to be able to calculate twiss functions

  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 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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 (

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Low-frequency RF Coupling To Unconventional (Fat Unbalanced) Dipoles

    SciTech Connect (OSTI)

    Ong, M M; Brown, C G; Perkins, M P; Speer, R D; Javedani, J B

    2010-12-07T23:59:59.000Z

    The report explains radio frequency (RF) coupling to unconventional dipole antennas. Normal dipoles have thin equal length arms that operate at maximum efficiency around resonance frequencies. In some applications like high-explosive (HE) safety analysis, structures similar to dipoles with ''fat'' unequal length arms must be evaluated for indirect-lightning effects. An example is shown where a metal drum-shaped container with HE forms one arm and the detonator cable acts as the other. Even if the HE is in a facility converted into a ''Faraday cage'', a lightning strike to the facility could still produce electric fields inside. The detonator cable concentrates the electric field and carries the energy into the detonator, potentially creating a hazard. This electromagnetic (EM) field coupling of lightning energy is the indirect effect of a lightning strike. In practice, ''Faraday cages'' are formed by the rebar of the concrete facilities. The individual rebar rods in the roof, walls and floor are normally electrically connected because of the construction technique of using metal wire to tie the pieces together. There are two additional requirements for a good cage. (1) The roof-wall joint and the wall-floor joint must be electrically attached. (2) All metallic penetrations into the facility must also be electrically connected to the rebar. In this report, it is assumed that these conditions have been met, and there is no arcing in the facility structure. Many types of detonators have metal ''cups'' that contain the explosives and thin electrical initiating wires, called bridge wires mounted between two pins. The pins are connected to the detonator cable. The area of concern is between the pins supporting the bridge wire and the metal cup forming the outside of the detonator. Detonator cables usually have two wires, and in this example, both wires generated the same voltage at the detonator bridge wire. This is called the common-mode voltage. The explosive component inside a detonator is relatively sensitive, and any electrical arc is a concern. In a safety analysis, the pin-to-cup voltage, i.e., detonator voltage, must be calculated to decide if an arc will form. If the electric field is known, the voltage between any two points is simply the integral of the field along a line between the points. Eq. 1.1. For simplicity, it is assumed that the electric field and dipole elements are aligned. Calculating the induced detonator voltage is more complex because of the field concentration caused by metal components. If the detonator cup is not electrically connected to the metal HE container, the portion of the voltage generated by the dipole at the detonator will divide between the container-to-cup and cup-to-pin gaps. The gap voltages are determined by their capacitances. As a simplification, it will be assumed the cup is electrically attached, short circuited, to the HE container. The electrical field in the pin-to-cup area is determined by the field near the dipole, the length of the dipole, the shape of the arms, and the orientation of the arms. Given the characteristics of a lightning strike and the inductance of the facility, the electric fields in the ''Faraday cage'' can be calculated. The important parameters for determining the voltage in an empty facility are the inductance of the rebars and the rate of change of the current, Eq. 1.3. The internal electric fields are directly related to the facility voltages, however, the electric fields in the pin-to-cup space is much higher than the facility fields because the antenna will concentrate the fields covered by the arms. Because the lightning current rise-time is different for every strike, the maximum electric field and the induced detonator voltage should be described by probability distributions. For pedantic purposes, the peak field in the simulations will be simply set to 1 V/m. Lightning induced detonator voltages can be calculated by scaling up with the facility fields. Any metal object around the explosives, such as a work stand, will also distort the electric

  6. 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...

  7. 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

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. Novel rf mems tunable filters with adjustable spurious suppression 

    E-Print Network [OSTI]

    Sekar, Vikram

    2009-05-15T23:59:59.000Z

    This thesis presents the theory and design of fixed and Radio Frequency (RF) Microelectromechanical Systems (MEMS) -based tunable microwave filters for RF and microwave applications. The methodology for the design of coupled resonator filters...

  14. Novel rf mems tunable filters with adjustable spurious suppression

    E-Print Network [OSTI]

    Sekar, Vikram

    2009-05-15T23:59:59.000Z

    This thesis presents the theory and design of fixed and Radio Frequency (RF) Microelectromechanical Systems (MEMS) -based tunable microwave filters for RF and microwave applications. The methodology for the design of coupled resonator filters...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Ion source with external RF antenna

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Ji, Qing; Wilde, Stephen

    2005-12-13T23:59:59.000Z

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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...

  7. 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.

  8. 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%.

  9. 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 ...

  10. 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 ...

  11. 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 ...

  12. 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

  13. 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.

  14. 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 ...

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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).

  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. 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 ...

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Induction heating of FeCo nanoparticles for rapid rf curing of epoxy K. J. Miller,1,a

    E-Print Network [OSTI]

    McHenry, Michael E.

    , and cracking of the polymer. An alternative curing process involves remote, noncontact rf heating of MNP loadedInduction heating of FeCo nanoparticles for rapid rf curing of epoxy composites K. J. Miller,1,a K epoxy composites through radio-frequency rf heating. The rf response of functionalized FeCo MNPs

  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. Simulation results of an inductively-coupled rf plasma torch in two and three dimensions for producing a metal matrix composite for nuclear fuel cladding

    E-Print Network [OSTI]

    Holik III, Eddie Frank (Trey)

    2009-05-15T23:59:59.000Z

    I propose to develop a new method for the synthesis of metal matrix composites (MMC) using aerosol reactants in a radio frequency (RF) plasma torch. An inductivelycoupled RF plasma torch (ICPT) may potentially be designed to maintain laminar flow...

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Suppressed Superconductivity on the Surface of Superconducting RF Quality Niobium for

    E-Print Network [OSTI]

    Suppressed Superconductivity on the Surface of Superconducting RF Quality Niobium for Particle 32310, USA Abstract. Significant performance degradation of superconducting RF (radio frequency) niobium superconductivity at chemically treated RF-quality niobium. We found that pinning of vortices along GBs is weaker

  8. Negative ion source with external RF antenna

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

    2007-02-13T23:59:59.000Z

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  9. 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.

  10. 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.

  11. 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.

  12. COLLISIONLESS ELECTRON HEATING IN RF GAS DISCHARGES: I. QUASILINEAR THEORY

    E-Print Network [OSTI]

    Kaganovich, Igor

    COLLISIONLESS ELECTRON HEATING IN RF GAS DISCHARGES: I. QUASILINEAR THEORY Yu.M. Aliev1 , I an interest in mechanisms of electron heating and power deposition in the plasma main- tained by radio{frequency (rf) electric elds. A modern trend in plasma technology aims at decreasing the gas pressures down

  13. Detection technique and front-end RF tunable filter for cognitive radio systems

    E-Print Network [OSTI]

    Park, Sanghoon

    2010-01-01T23:59:59.000Z

    dual-mode WiMAX/WLAN direct- conversion receiver,” in Proc.Hamilton, “Aspects of direct conversion receiver design,” inand M. Ismail, “A direct conversion WiMAX RF receiver front-

  14. 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...

  15. 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)

  16. 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

  17. Design of a high quality factor spiral inductors in RF MCM-D

    E-Print Network [OSTI]

    Peters, Joshua, 1981-

    2004-01-01T23:59:59.000Z

    This thesis studies the design and fabrication of spiral inductors for use in Radio Frequency (RF) applications. A design methodology is developed to search an inductor design space efficiently using existing simulation ...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  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. 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.

  6. Matching network for RF plasma source

    DOE Patents [OSTI]

    Pickard, Daniel S. (Palo Alto, CA); Leung, Ka-Ngo (Hercules, CA)

    2007-11-20T23:59:59.000Z

    A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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).

  12. 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

  13. Design methodologies for built-in testing of integrated RF transceivers with the on-chip loopback technique

    E-Print Network [OSTI]

    Onabajo, Marvin Olufemi

    2009-05-15T23:59:59.000Z

    Advances toward increased integration and complexity of radio frequency (RF) andmixed-signal integrated circuits reduce the effectiveness of contemporary testmethodologies and result in a rising cost of testing. The focus in this research...

  14. 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.

  15. 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.

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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.

  20. RF-MEMS Switched Varactors for Medium Power Applications

    E-Print Network [OSTI]

    Maury, F; Crunteanu, A; Conseil, F; Blondy, P

    2008-01-01T23:59:59.000Z

    In RF (Radio Frequency) domain, one of the limitations of using MEMS (Micro Electromechanical Systems) switching devices for medium power applications is RF power. Failure phenomena appear even for 500 mW. A design of MEMS switched capacitors with an enhanced topology is presented in this paper to prevent it. This kind of device and its promising performances will serve to fabricate a MEMS based phase shifter able to work under several watts.

  1. 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

  2. A Parametric Study of Electron Extraction from a Low Frequency Inductively Coupled RF-Plasma Source

    E-Print Network [OSTI]

    -cathode is closed only by the ion current to the cathode chamber wall. The extraction of electrons from the rf through this opening is larger than the ion saturation current to the chamber wall, then the maximum by the plasma density in the cathode chamber, the ion Bohm velocity at the sheath edge and the surface area

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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...

  11. 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.

  12. 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.

  13. Development of a 1319 nm Laser Radar using Fiber-Optics and RF Pulse Compression: Receiver Characterization

    E-Print Network [OSTI]

    Kansas, University of

    Development of a 1319 nm Laser Radar using Fiber-Optics and RF Pulse Compression: Receiver and commercially available fiber-optic technologies. We use radio frequency (RF) pulse compression and digital commensurate with the desired range accuracy. With today's off-the-shelf fiber-optic components, multi

  14. Tubular Radio Frequency (RF) Cage Field Confinement Cavity (IN-05-107) -

    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'sis Taking Over OurThe Iron Spin Transition in2,EHSS A-Z SiteManhattanPacific: A YearResearchEnergy

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

    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

  16. 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...

  17. Si-based RF MEMS components.

    SciTech Connect (OSTI)

    Stevens, James E.; Nordquist, Christopher Daniel; Baker, Michael Sean; Fleming, James Grant; Stewart, Harold D.; Dyck, Christopher William

    2005-01-01T23:59:59.000Z

    Radio frequency microelectromechanical systems (RF MEMS) are an enabling technology for next-generation communications and radar systems in both military and commercial sectors. RF MEMS-based reconfigurable circuits outperform solid-state circuits in terms of insertion loss, linearity, and static power consumption and are advantageous in applications where high signal power and nanosecond switching speeds are not required. We have demonstrated a number of RF MEMS switches on high-resistivity silicon (high-R Si) that were fabricated by leveraging the volume manufacturing processes available in the Microelectronics Development Laboratory (MDL), a Class-1, radiation-hardened CMOS manufacturing facility. We describe novel tungsten and aluminum-based processes, and present results of switches developed in each of these processes. Series and shunt ohmic switches and shunt capacitive switches were successfully demonstrated. The implications of fabricating on high-R Si and suggested future directions for developing low-loss RF MEMS-based circuits are also discussed.

  18. A computer program for HVDC converter station RF noise calculations

    SciTech Connect (OSTI)

    Kasten, D.G.; Caldecott, R.; Sebo, S.A. (Ohio State Univ., Columbus, OH (United States). Dept. of Electrical Engineering); Liu, Y. (Virginia Polytechnic Inst. State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

    1994-04-01T23:59:59.000Z

    HVDC converter station operations generate radio frequency (RF) electromagnetic (EM) noise which could interfere with adjacent communication and computer equipment, and carrier system operations. A generic Radio Frequency Computer Analysis Program (RAFCAP) for calculating the EM noise generated by valve ignition of a converter station has been developed as part of a larger project. The program calculates RF voltages, currents, complex power, ground level electric field strength and magnetic flux density in and around an HVDC converter station. The program requires the converter station network to be represented by frequency dependent impedance functions. Comparisons of calculated and measured values are given for an actual HVDC station to illustrate the validity of the program. RAFCAP is designed to be used by engineers for the purpose of calculating the RF noise produced by the igniting of HVDC converter valves.

  19. 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...

  20. 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.

  1. 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.

  2. A Beat Frequency RF Modulator for Generation of Low Repetition Rate Electron Microbunches for the CEBAF Polarized Source

    SciTech Connect (OSTI)

    John Musson; Reza Kazimi; Benard Poelker; Joseph Grames; John Hansknecht

    2007-06-25T23:59:59.000Z

    Fiber-based drive lasers now produce all of the spin-polarized electron beams at CEBAF/Jefferson Lab. The flexibility of these drive lasers, combined with the existing three-beam CEBAF photoinjector Chopper, provides a means to implement a beat frequency technique to produce long time intervals between individual electron microbunches (tens of nanoseconds) by merely varying the nominal 499 MHz drive laser frequency by < 20%. This submission describes the RF Laser modulator that uses a divider and heterodyne scheme to maintain coherence with the accelerator Master Oscillator (MO), while providing delay resolution in increments of 2ns. Some possible uses for such a beam are discussed as well as intended future development.

  3. 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.

  4. Phase modulation in RF tag

    DOE Patents [OSTI]

    Carrender, Curtis Lee; Gilbert, Ronald W.

    2007-02-20T23:59:59.000Z

    A radio frequency (RF) communication system employs phase-modulated backscatter signals for RF communication from an RF tag to an interrogator. The interrogator transmits a continuous wave interrogation signal to the RF tag, which based on an information code stored in a memory, phase-modulates the interrogation signal to produce a backscatter response signal that is transmitted back to the interrogator. A phase modulator structure in the RF tag may include a switch coupled between an antenna and a quarter-wavelength stub; and a driver coupled between the memory and a control terminal of the switch. The driver is structured to produce a modulating signal corresponding to the information code, the modulating signal alternately opening and closing the switch to respectively decrease and increase the transmission path taken by the interrogation signal and thereby modulate the phase of the response signal. Alternatively, the phase modulator may include a diode coupled between the antenna and driver. The modulating signal from the driver modulates the capacitance of the diode, which modulates the phase of the response signal reflected by the diode and antenna.

  5. Communication methods, systems, apparatus, and devices involving RF tag registration

    DOE Patents [OSTI]

    Burghard, Brion J. (W. Richland, WA); Skorpik, James R. (Kennewick, WA)

    2008-04-22T23:59:59.000Z

    One technique of the present invention includes a number of Radio Frequency (RF) tags that each have a different identifier. Information is broadcast to the tags from an RF tag interrogator. This information corresponds to a maximum quantity of tag response time slots that are available. This maximum quantity may be less than the total number of tags. The tags each select one of the time slots as a function of the information and a random number provided by each respective tag. The different identifiers are transmitted to the interrogator from at least a subset of the RF tags.

  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. 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.

  8. 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.

  9. 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.

  10. 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. ...

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Phase stable RF transport system

    DOE Patents [OSTI]

    Curtin, Michael T. (Los Alamos, NM); Natter, Eckard F. (San Francisco, CA); Denney, Peter M. (Los Alamos, NM)

    1992-01-01T23:59:59.000Z

    An RF transport system delivers a phase-stable RF signal to a load, such as an RF cavity of a charged particle accelerator. A circuit generates a calibration signal at an odd multiple frequency of the RF signal where the calibration signal is superimposed with the RF signal on a common cable that connects the RF signal with the load. Signal isolating diplexers are located at both the RF signal source end and load end of the common cable to enable the calibration to be inserted and extracted from the cable signals without any affect on the RF signal. Any phase shift in the calibration signal during traverse of the common cable is then functionally related to the phase shift in the RF signal. The calibration phase shift is used to control a phase shifter for the RF signal to maintain a stable RF signal at the load.

  19. Verification of particle simulation of radio frequency waves in fusion Animesh Kuley,1,2,a)

    E-Print Network [OSTI]

    Lin, Zhihong

    recognized from the early days of magnetically confined plasma research.1,2 The RF waves provide one

  20. 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

  1. 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.

  2. JOURNAL DE PHYSIQUE CoZZoque C7, suppte'ment au n07, Tome 40, JuiZZet 1979, page C7-477 THE RF-ION SOURCE RIG 10FOR INTENSEHYDROGEN ION BEAMS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    - are accelerated,too, by the s w mechanism. We obtain an intense electrodeless, non-them1 rf-plasma. The ham- advantages of our rf-plasma source called RIG 10 (-Radio-Frequency- Ion-erator of 10 an in diameter): This type of ion- source has no discharge electrodes immersed in the discharge plasma

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  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. 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

  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. 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

  13. 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

  14. 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

  15. 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.

  16. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, Eiichi (Los Alamos, NM); Roeder, Stephen B. W. (La Mesa, CA); Assink, Roger A. (Albuquerque, NM); Gibson, Atholl A. V. (Bryan, TX)

    1986-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  17. Radio-frequency powered glow discharge device and method with high voltage interface

    DOE Patents [OSTI]

    Duckworth, Douglas C. (Knoxville, TN); Marcus, R. Kenneth (Clemson, SC); Donohue, David L. (Vienna, AT); Lewis, Trousdale A. (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components.

  18. Radio-frequency powered glow discharge device and method with high voltage interface

    DOE Patents [OSTI]

    Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.

    1994-06-28T23:59:59.000Z

    A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.

  19. RF Characterization of Niobium Films for Superconducting Cavities

    E-Print Network [OSTI]

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01T23:59:59.000Z

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  20. 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.

  1. 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.

  2. Ways to improve the efficiency and reliability of radio frequency driven negative ion sources for fusion

    SciTech Connect (OSTI)

    Kraus, W., E-mail: kraus@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); Briefi, S.; Fantz, U. [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany) [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany); Gutmann, P.; Doerfler, J. [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)] [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)

    2014-02-15T23:59:59.000Z

    Large RF driven negative hydrogen ion sources are being developed at IPP Garching for the future neutral beam injection system of ITER. The overall power efficiency of these sources is low, because for the RF power supply self-excited generators are utilized and the plasma is generated in small cylindrical sources (“drivers”) and expands into the source main volume. At IPP experiments to reduce the primary power and the RF power required for the plasma production are performed in two ways: The oscillator generator of the prototype source has been replaced by a transistorized RF transmitter and two alternative driver concepts, a spiral coil, in which the field is concentrated by ferrites, which omits the losses by plasma expansion and a helicon source are being tested.

  3. Faraday Acceleration with Radio-frequency Assisted Discharge (FARAD) Edgar Y. Choueiri

    E-Print Network [OSTI]

    Choueiri, Edgar

    . Polzin Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL) Mechanical and Aerospace Engineering electrodeless accelerator concept that relies on an RF-assisted discharge, an applied magnetic field efficient plasma production, magnetic field guided mass injection, and electromagnetic acceleration

  4. On the applicability of Sato's equation to capacitative radio frequency sheaths

    E-Print Network [OSTI]

    J. Balakrishnan; G. R. Nagabhushana

    2003-10-08T23:59:59.000Z

    We show that the time dependent version of Sato's equation, when applied to capacitative rf sheaths is no longer independent of the electric field of the space charge, and discuss the use of the equation for a specific sheath model.

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Intelligent Low-level RF System by Non-destructive Beam Monitoring Device for Cyclotrons

    E-Print Network [OSTI]

    Malafeh, M S Sharifi Asadi; Afarideh, H; Chai, J S

    2015-01-01T23:59:59.000Z

    The project of a10MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work Intelligent Low Level Radio Frequency Circuit or ILLRF suitable for Most of the AVF cyclotron accelerators was designed by the beam monitoring device and narrow band tunable band-pass filter. In this design, for the RF phase detection does not need to signal processing by microcontroller

  13. Design of HOM coupler prototype for the APT superconducting RF cavities

    SciTech Connect (OSTI)

    Kuzminski, J. (Jozef); Spalek, G. (George); Bourque, R. F. (Robert F.)

    2001-01-01T23:59:59.000Z

    Beam dynamics calculations for the Accelerator Production of Tritium (APT) proton linac suggest that wakefields, which are excited during beam operation, would not lead to beam-breakup instabilities. However, in the superconducting (SC) radio-frequency (RF) cavities of the APT linac, higher-order modes (HOMs), whose frequencies are below the beam tube cut-off fiequency, can be sufficiently excited by the beam to add significantly to the heat load removed by the helium refrigerator. In this paper, we present a design of an HOM coupler for the APT RF cavities that will remove this power to a resistive load at room temperature.

  14. Microphonics detuning compensation in 3.9 GHZ superconducting RF cavities

    SciTech Connect (OSTI)

    Ruben Carcagno et al.

    2003-10-20T23:59:59.000Z

    Mechanical vibrations can detune superconducting radio frequency (SCRF) cavities unless a tuning mechanism counteracting the vibrations is present. Due to their narrow operating bandwidth and demanding mechanical structure, the 13-cell 3.9GHz SCRF cavities for the Charged Kaons at Main Injector (CKM) experiment at Fermilab are especially susceptible to this microphonic phenomena. We present early results correlating RF frequency detuning with cavity vibration measurements for CKM cavities; initial detuning compensation results with piezoelectric actuators are also presented.

  15. 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.

  16. Towards a 3D time dependent Fokker-Planck solver for modelling RF heating in realistic tokamak geometry

    E-Print Network [OSTI]

    . Hedin, Ion Cyclotron Heating in Toroidal Plasmas, Ph.D. thesis, Royal Institute of Technology StockholmTowards a 3D time dependent Fokker-Planck solver for modelling RF heating in realistic tokamak supercomputers and the need for predictive tools to guide the experiments, modelling radio frequency heating

  17. 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.

  18. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect (OSTI)

    Qian, Di; Bottomley, Paul A. [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); El-Sharkawy, AbdEl-Monem M.; Edelstein, William A., E-mail: w.edelstein@gmail.com [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ?3%. With the torso landmarked at the xiphoid, human adult whole?body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.

  19. Structural properties of dusty plasma in direct current and radio frequency gas discharges

    SciTech Connect (OSTI)

    Ramazanov, T. S.; Dzhumagulova, K. N.; Jumabekov, A. N.; Dosbolayev, M. K. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty, 050012 (Kazakhstan)

    2008-05-15T23:59:59.000Z

    This paper presents radial distribution functions of dust particles obtained experimentally in dc and rf discharges. Pressure and interaction energy of dusty particles were calculated on the basis of these functions. The Langevin dynamics computer simulation for each experiment was performed. The comparisons with computer simulations are made.

  20. Faraday Acceleration with Radio-frequency Assisted Discharge Edgar Y. Choueiri and Kurt A. Polzin

    E-Print Network [OSTI]

    Choueiri, Edgar

    Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL) Princeton University, Mechanical and Aerospace Abstract A new electrodeless accelerator concept that relies on an RF-assisted discharge, an applied of a preionized plasma allows for current sheet formation at lower discharge voltages and energies than those

  1. Single Stage Faraday Accelerator with Radio-frequency Assisted Discharge (SS-FARAD)

    E-Print Network [OSTI]

    Choueiri, Edgar

    -assisted, pulsed, electrodeless accelerator concept that utilizes a single antenna coil for plasma generation be sufficiently isolated from the RF source without significant adverse affects on plasma generation. Nomenclature Pulsed inductive plasma accelerators are seen as a way to overcome major obstacles in other electric

  2. 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.

  3. 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 ...

  4. Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

    1984-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. 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.

  10. Method and apparatus for transferring and injecting rf energy from a generator to a resonant load

    DOE Patents [OSTI]

    Hoffert, William J. (Albuquerque, NM)

    1987-01-01T23:59:59.000Z

    Improved apparatus and method are provided for the coherent amplification and injection of radio-frequency (rf) energy into a load cavity using a plurality of amplifier tubes. A plurality of strip line cavities (30, 32, 34, 36, 40, 42, 44) are laterally joined to define a continuous closed cavity (48), with an amplifier tube (50, 52, 54, 56, 58, 60, 62, 64) mounted within each resonant strip cavity. Rf energy is injected into the continuous cavity (48) from a single input (70) for coherent coupling to all of the amplifier tubes for amplification and injection into the load cavity (76).

  11. About the conditions of suppression of turbulence effects on the poloidal fluxes in thoroidal plasmas in the presence of RF heating

    E-Print Network [OSTI]

    plasmas in the presence of RF heating N. Pometescu University of Craiova, Association EURATOM of the poloidal particle and heat fluxes in the thoroidal plasmas due to electrostatic turbulence in the presence of external Radio Frequency heating. The effects of the electrostatic turbulence contain two terms. One

  12. Monolithic RF frontends for ubiquitous wireless connectivity

    E-Print Network [OSTI]

    Goswami, Sushmit

    2014-01-01T23:59:59.000Z

    The desire for ubiquitous connectivity is pushing radios towards highly-integrated, multi-standard and multi-band implementations. This thesis explores architectures for next-generation RF frontends, which form the interface ...

  13. 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...

  14. Observation of ? mode electron heating in dusty argon radio frequency discharges

    SciTech Connect (OSTI)

    Killer, Carsten; Bandelow, Gunnar; Schneider, Ralf; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany); Matyash, Konstantin [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2013-08-15T23:59:59.000Z

    The time-resolved emission of argon atoms in a dusty plasma has been measured with phase-resolved optical emission spectroscopy using an intensified charge-coupled device camera. For that purpose, three-dimensional dust clouds have been confined in a capacitively coupled rf argon discharge with the help of thermophoretic levitation. While electrons are exclusively heated by the expanding sheath (? mode) in the dust-free case, electron heating takes place in the entire plasma bulk when the discharge volume is filled with dust particles. Such a behavior is known as ? mode, first observed in electronegative plasmas. Furthermore, particle-in-cell simulations have been carried out, which reproduce the trends of the experimental findings. These simulations support previous numerical models showing that the enhanced atomic emission in the plasma can be attributed to a bulk electric field, which is mainly caused by the reduced electrical conductivity due to electron depletion.

  15. High thermal expansion sealing glass for use in radio frequency applications

    DOE Patents [OSTI]

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

    1999-01-01T23:59:59.000Z

    The present invention provides a glass composition for hermetically sealing to high thermal expansion materials such as aluminum alloys, stainless steels, and copper alloys, which includes between about 10 and about 25 mole percent Na.sub.2 O, between about 10 and about 25 mole percent K.sub.2 O, between about 4 and about 15 mole percent Al.sub.2 O.sub.3, between about 35 and about 50 mole percent P.sub.2 O.sub.5, B.sub.2 O.sub.3 in a concentration not exceeding 10 mole percent, and MXO in a concentration not exceeding 12 mole percent, wherein MXO is a metal oxide selected from the group consisting of PbO, BaO, CaO and MgO or a mixture thereof. This composition is suitable to hermetically seal to components for use in RF-interconnection applications.

  16. Second-order radio frequency kinetic theory revisited: Resolving inconsistency with conventional fluid theory

    SciTech Connect (OSTI)

    Chen, Jiale [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei (China); Gao, Zhe [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China) [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei (China)

    2013-08-15T23:59:59.000Z

    The second-order velocity distribution function was calculated from the second-order rf kinetic theory [Jaeger et al., Phys. Plasmas 7, 641 (2000)]. However, the nonresonant ponderomotive force in the radial direction derived from the theory is inconsistent with that from the fluid theory. The inconsistency arises from that the multiple-timescale-separation assumption fails when the second-order Vlasov equation is directly integrated along unperturbed particle orbits. A slowly ramped wave field including an adiabatic turn-on process is applied in the modified kinetic theory in this paper. Since this modification leads only to additional reactive/nonresonant response relevant with the secular resonant response from the previous kinetic theory, the correct nonresonant ponderomotive force can be obtained while all the resonant moments remain unchanged.

  17. 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, ...

  18. 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 ...

  19. RF telemetry makes complex surveys quick, cost-effective

    SciTech Connect (OSTI)

    Rigdon, H.K. [Nemaha Resources, Inc., Tulsa, OK (United States)

    1996-05-01T23:59:59.000Z

    Field seismic crews can gather full-range or wide-azimuth seismic datasets for 3-D surveys at costs competitive with 2-D seismic acquisition through the use of Radio Frequency (RF) telemetry acquisition systems. By eliminating need for data cables, RF telemetry systems, such as the Opseis Eagle System, can record 3-D data volumes using proven 2-D recording geometries that are a natural extension of one-dimensional (split spread) design. Design advantages include: (1) uniform sampling in both X (in-line) and Y (lateral) directions; (2) excellent offset and azimuthal distribution common to each 3-D stacking bin, and (3) uniform fold across the survey area necessary for amplitude analysis.

  20. Design of a horizontal test cryostat for superconducting RF cavities for the FREIA facility at Uppsala University

    SciTech Connect (OSTI)

    Chevalier, N. R.; Thermeau, J.-P.; Bujard, P.; Junquera, T. [Accelerators and Cryogenic Systems (ACS), 86 rue de Paris, 91400 Orsay (France); Hermansson, L.; Kern, R. Santiago; Ruber, R. [Uppsala University, Department of Physics and Astronomy, 75120 Uppsala (Sweden)

    2014-01-29T23:59:59.000Z

    Uppsala University is constructing a large scale facility, called FREIA (Facility for Research Instrumentation and Accelerator Development). FREIA includes a helium liquefier and an accelerator test facility and has the capacity to test superconducting radio-frequency (RF) cavities with the same RF system and RF power level as in an accelerator. A central element of FREIA is a horizontal test cryostat connected in closed loop to a helium liquefier. This cryostat can house two fully equipped (tuners, piezo, power coupler, helium tank) superconducting cavities to perform full RF high power tests and operate at temperatures between 1.8 K and 4.2 K. The cryostat is designed to accommodate a large array of superconducting cavities and magnets, among which the European Spallation Source (ESS) type spoke and high-? elliptical cavities as well as TESLA/ILC type elliptical cavities. The present status of the project and the design of the cryostat are reported.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Muon spin rotation studies of niobium for superconducting RF applications

    E-Print Network [OSTI]

    Grassellino, A; Kolb, P; Laxdal, R; Lockyer, N S; Longuevergne, D; Sonier, J E

    2013-01-01T23:59:59.000Z

    In this work we investigate superconducting properties of niobium samples via application of the muon spin rotation/relaxation (muSR) technique. We employ for the first time the muSR technique to study samples that are cutout from large and small grain 1.5 GHz radio frequency (RF) single cell niobium cavities. The RF test of these cavities was accompanied by full temperature mapping to characterize the RF losses in each of the samples. Results of the muSR measurements show that standard cavity surface treatments like mild baking and buffered chemical polishing (BCP) performed on the studied samples affect their surface pinning strength. We find an interesting correlation between high field RF losses and field dependence of the sample magnetic volume fraction measured via muSR. The muSR line width observed in ZF-muSR measurements matches the behavior of Nb samples doped with minute amounts of Ta or N impurities. An upper bound for the upper critical field Hc2 of these cutouts is found.

  8. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron

    E-Print Network [OSTI]

    Brian Chase; Ralph Pasquinelli; Ed Cullerton; Philip Varghese

    2014-11-21T23:59:59.000Z

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  9. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron

    E-Print Network [OSTI]

    Chase, Brian; Cullerton, Ed; Varghese, Philip

    2015-01-01T23:59:59.000Z

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  10. Final Technical Report- Back-gate Field Emission-based Cathode RF Electron Gun

    SciTech Connect (OSTI)

    McGuire, Gary; Martin, Allen; Noonan, John

    2010-10-30T23:59:59.000Z

    The objective was to complete the design of an electron gun which utilizes a radio frequency (RF) power source to apply a voltage to a field emission (FE) cathode, a so called cold cathode, in order to produce an electron beam. The concept of the RF electron gun was originally conceived at Argonne National Laboratory but never reduced to practice. The research allowed the completion of the design based upon the integration of the FE electron source. Compared to other electron guns, the RF gun is very compact, less than one third the size of other comparable guns, and produces a high energy (to several MeV), high quality, high power electron beam with a long focal length with high repetition rates. The resultant electron gun may be used in welding, materials processing, analytical equipment and waste treatment.

  11. Phase-resolved optical emission of dusty rf discharges: Experiment and simulation

    SciTech Connect (OSTI)

    Melzer, Andre; Huebner, Simon; Lewerentz, Lars; Schneider, Ralf [Institut fuer Physik, Ernst-Moritz-Arndt-Universiaet, D-17489 Greifswald (Germany); Matyash, Konstantin [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Ikkurthi, Ramana [Institute for Plasma Research, Bhat, Ghandinagar, Gujarat (India)

    2011-03-15T23:59:59.000Z

    The spectral emission of atoms in a dusty radio frequence (rf) discharge plasma in argon and helium has been measured with a gated ICCD camera. The spatially and temporally resolved emission/excitation of the argon and helium atoms during the rf cycle in the dusty discharge was compared to the dust-free case. In the bulk plasma above the dust cloud, the emission is clearly enhanced in the dusty discharge with respect to the pure discharge, whereas in the sheath the emission is reduced. In addition, the emission of a dusty argon plasma is studied via particle-particle particle-mesh (P{sup 3}M) simulations. The rf dynamics with a single dust particle trapped in the sheath was calculated. Like in the experiment the dust modifies the atomic emission. The spatiotemporal excitation pattern of the experiment is reproduced and a detailed understanding of the difference in excitation of the discharge with and without dust is presented.

  12. 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.

  13. 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...

  14. 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.

  15. 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,...

  16. 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.

  17. Continued development of modeling tools and theory for RF heating

    SciTech Connect (OSTI)

    NONE

    1998-12-01T23:59:59.000Z

    Mission Research Corporation (MRC) is pleased to present the Department of Energy (DOE) with its renewal proposal to the Continued Development of Modeling Tools and Theory for RF Heating program. The objective of the program is to continue and extend the earlier work done by the proposed principal investigator in the field of modeling (Radio Frequency) RF heating experiments in the large tokamak fusion experiments, particularly the Tokamak Fusion Test Reactor (TFTR) device located at Princeton Plasma Physics Laboratory (PPPL). An integral part of this work is the investigation and, in some cases, resolution of theoretical issues which pertain to accurate modeling. MRC is nearing the successful completion of the specified tasks of the Continued Development of Modeling Tools and Theory for RF Heating project. The following tasks are either completed or nearing completion. (1) Anisotropic temperature and rotation upgrades; (2) Modeling for relativistic ECRH; (3) Further documentation of SHOOT and SPRUCE. As a result of the progress achieved under this project, MRC has been urged to continue this effort. Specifically, during the performance of this project two topics were identified by PPPL personnel as new applications of the existing RF modeling tools. These two topics concern (a) future fast-wave current drive experiments on the large tokamaks including TFTR and (c) the interpretation of existing and future RF probe data from TFTR. To address each of these topics requires some modification or enhancement of the existing modeling tools, and the first topic requires resolution of certain theoretical issues to produce self-consistent results. This work falls within the scope of the original project and is more suited to the project`s renewal than to the initiation of a new project.

  18. Charging and de-charging of dust particles in bulk region of a radio frequency discharge plasma

    SciTech Connect (OSTI)

    Mishra, S. K. [Institute for Plasma Research, Gandhinagar 382428 (India); Misra, Shikha; Sodha, M. S. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

    2013-03-15T23:59:59.000Z

    An analysis to investigate the effect of the dust particle size and density on the floating potential of the dust particles of uniform radius and other plasma parameters in the bulk region plasma of a RF-discharge in collisionless/collisional regime has been presented herein. For this purpose, the average charge theory based on charge balance on dust and number balance of plasma constituents has been utilized; a derivation for the accretion rate of electrons corresponding to a drifting Maxwellian energy distribution in the presence of an oscillatory RF field has been given and the resulting expression has been used to determine the floating potential of the dust grains. Further, the de-charging of the dust grains after switching off the RF field has also been discussed.

  19. 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.

  20. "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

  1. 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

  2. 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.

  3. Radio frequency-power and the ring-mode to red-mode transition in an inductively coupled plasma

    SciTech Connect (OSTI)

    Coffer, J. G.; Camparo, J. C. [Physical Sciences Laboratories, The Aerospace Corporation, P.O. Box 92957, Los Angeles, California 90009 (United States)

    2012-04-15T23:59:59.000Z

    The optical output of an alkali-metal inductively coupled plasma (alkali-ICP) plays an important role in both atomic magnetometers and atomic clocks, producing these devices' atomic signals through optical pumping. Unfortunately, though the alkali-ICP's optical pumping efficiency grows exponentially with temperature, at relatively high temperatures ({approx}140 deg. C) the discharge transitions from ''ring mode'' to ''red mode'', which is a spectral change in the plasma's output that corresponds broadly to a transition from ''good emission'' for optical pumping to ''poor emission.'' Recently, evidence has accumulated pointing to radiation trapping as the mechanism driving the ring-mode to red-mode transition, suggesting that the phenomenon is primarily linked to the alkali vapor's temperature. However, observations of the transition made in the 1960 s, demonstrating that the ICP temperature associated with the transition depended on rf-power, would appear to cast doubt on this mechanism. Here, we carefully investigate the influence of rf-power on the ring-mode to red-mode transition, finding that rf-power only affects the transition through discharge heating. Thus, the present work shows that the primary effect of rf-power on the ring-mode to red-mode transition can be understood in terms of the radiation trapping mechanism.

  4. RF power generation

    E-Print Network [OSTI]

    Carter, R G

    2011-01-01T23:59:59.000Z

    This paper reviews the main types of r.f. power amplifiers which are, or may be, used for particle accelerators. It covers solid-state devices, tetrodes, inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for the different technologies.

  5. 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...

  6. IBM Systems and Technology IBM 7RF SOI

    E-Print Network [OSTI]

    switches, antenna tuners, low noise amplifiers and power amplifiers found in the front end of today distortion device (LowD) option: Boosts performance of the 7RF SOI offering and enables designers to further smartphone radio com- plexity with a silicon offering optimized for RF front-end applications Reduce area

  7. Superconducting RF Injector T. Srinivasan-Rao

    E-Print Network [OSTI]

    current injector Heat LossRF Requirements Superconducting injector Photocathode Cesium Telluride Nb(degrees) Cooled to 4 K. Undercoupled Frequency: ~1301.5727 MHz, Loaded Q:~1x107-Contaminants effect? Freq. Vs

  8. Self-consistent electrodynamics of large-area high-frequency capacitive plasma discharge

    SciTech Connect (OSTI)

    Chen Zhigang; Rauf, Shahid; Collins, Ken [Applied Materials, Inc., 974 E. Arques Avenue, Sunnyvale, California 94085 (United States)

    2010-10-15T23:59:59.000Z

    Capacitively coupled plasmas (CCPs) generated using high frequency (3-30 MHz) and very high frequency (30-300 MHz) radio-frequency (rf) sources are used for many plasma processing applications including thin film etching and deposition. When chamber dimensions become commensurate with the effective rf wavelength in the plasma, electromagnetic wave effects impose a significant influence on plasma behavior. Because the effective rf wavelength in plasma depends upon both rf and plasma process conditions (e.g., rf power and gas pressure), a self-consistent model including both the rf power delivery system and the plasma discharge is highly desirable to capture a more complete physical picture of the plasma behavior. A three-dimensional model for self-consistently studying both electrodynamic and plasma dynamic behavior of large-area (Gen 10, >8 m{sup 2}) CCP is described in this paper. This model includes Maxwell's equations and transport equations for charged and neutral species, which are coupled and solved in the time domain. The complete rf plasma discharge chamber including the rf power delivery subsystem, rf feed, electrodes, and the plasma domain is modeled as an integrated system. Based on this full-wave solution model, important limitations for processing uniformity imposed by electromagnetic wave propagation effects in a large-area CCP (3.05x2.85 m{sup 2} electrode size) are studied. The behavior of H{sub 2} plasmas in such a reactor is examined from 13.56 to 200 MHz. It is shown that various rectangular harmonics of electromagnetic fields can be excited in a large-area rectangular reactor as the rf or power is increased. The rectangular harmonics can create not only center-high plasma distribution but also high plasma density at the corners and along the edges of the reactor.

  9. 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.

  10. Non-ambipolar radio-frequency plasma electron source and systems and methods for generating electron beams

    DOE Patents [OSTI]

    Hershkowitz, Noah (Madison, WI); Longmier, Benjamin (Madison, WI); Baalrud, Scott (Madison, WI)

    2009-03-03T23:59:59.000Z

    An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.

  11. Cs2Te normal conducting photocathodes in the superconducting rf gun

    E-Print Network [OSTI]

    Xiang, R; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schamlott, A; Schneider, Ch; Schurig, R; Staufenbiel, F; Teichert, J

    2010-01-01T23:59:59.000Z

    The superconducting radio frequency photoinjector (SRF gun) is one of the latest applications of superconducting rf technology in the accelerator field. Since superconducting photocathodes with high quantum efficiency are yet unavailable, normal conducting cathode material is the main choice for SRF photoinjectors. However, the compatibility between the photocathode and the cavity is one of the challenges for this concept. Recently, a SRF gun with Cs2Te cathode has been successfully operated in Forschungszentrum Dresden-Rossendorf. In this paper, we will present the physical properties of Cs2Te photocathodes in the SC cavity, such as the quantum efficiency, the lifetime, the rejuvenation, the charge saturation, and the dark current.

  12. Plasma processing of large curved surfaces for superconducting rf cavity modification

    SciTech Connect (OSTI)

    Upadhyay, J.; Im, Do; Popovi??, S.; Valente-Feliciano, A.-M.; Phillips, L.; Vuskovic, L

    2014-12-01T23:59:59.000Z

    Plasma based surface modification of niobium is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The development of the technology based on Cl2/Ar plasma etching has to address several crucial parameters which influence the etching rate and surface roughness, and eventually, determine cavity performance. This includes dependence of the process on the frequency of the RF generator, gas pressure, power level, the driven (inner) electrode configuration, and the chlorine concentration in the gas mixture during plasma processing. To demonstrate surface layer removal in the asymmetric non-planar geometry, we are using a simple cylindrical cavity with 8 ports symmetrically distributed over the cylinder. The ports are used for diagnosing the plasma parameters and as holders for the samples to be etched. The etching rate is highly correlated with the shape of the inner electrode, radio-frequency (RF) circuit elements, chlorine concentration in the Cl2/Ar gas mixtures, residence time of reactive species and temperature of the cavity. Using cylindrical electrodes with variable radius, large-surface ring-shaped samples and d.c. bias implementation in the external circuit we have demonstrated substantial average etching rates and outlined the possibility to optimize plasma properties with respect to maximum surface processing effect.

  13. The effect of proton irradiation on the RF performance of SiGe HBTs

    SciTech Connect (OSTI)

    Zhang, S.; Niu, G.; Cressler, J.D.; Clark, S.D.; Ahlgren, D.C.

    1999-12-01T23:59:59.000Z

    The effects of proton irradiation on the RF performance of SiGe Heterojunction Bipolar Transistors (HBTs) are reported in this paper. Frequency response and broadband noise properties are investigated in SiGe HBTs for proton fluences up to 5 x 10{sup 13} p/cm{sup 2}. The current gain in the radio frequency (RF) bias region and the cutoff frequency (f{sub T}) show little degradation at even extreme proton fluence (realistic space fluences are 1--5 x 10{sup 11} p/cm{sup 2}). The slight degradation of NF{sub min} is due to the irradiation-induced increase in the total emitter and base resistance. The associated available gain G{sub A,assoc} at noise matching is 20.2 dB at f = 2 GHz and I{sub C} = 2.6 mA for a proton fluence of 5 x 10{sup 13} p/cm{sup 2}. These results suggest that space-borne RF circuit applications of SiGe HBTs should be robust to proton irradiation.

  14. 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

  15. Low jitter RF distribution system

    DOE Patents [OSTI]

    Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

    2012-09-18T23:59:59.000Z

    A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

  16. 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

  17. Superconducting RF Cryomodule Demagnetization

    E-Print Network [OSTI]

    Crawford, Anthony C

    2015-01-01T23:59:59.000Z

    This note presents measurements that support the proposition that it is feasible to demagnetize a fully assembled superconducting RF cryomodule.

  18. 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.

  19. 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. %.

  20. High-Power Rf Load

    DOE Patents [OSTI]

    Tantawi, Sami G. (San Mateo, CA); Vlieks, Arnold E. (Livermore, CA)

    1998-09-01T23:59:59.000Z

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  1. Design and operation of a rotating drum radio frequency plasma reactor for the modification of free nanoparticles

    SciTech Connect (OSTI)

    Shearer, Jeffrey C.; Fisher, Ellen R. [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

    2013-06-15T23:59:59.000Z

    A rotating drum rf plasma reactor was designed to functionalize the surface of nanoparticles and other unusually shaped substrates through plasma polymerization and surface modification. This proof-of-concept reactor design utilizes plasma polymerized allyl alcohol to add OH functionality to Fe{sub 2}O{sub 3} nanoparticles. The reactor design is adaptable to current plasma hardware, eliminating the need for an independent reactor setup. Plasma polymerization performed on Si wafers, Fe{sub 2}O{sub 3} nanoparticles supported on Si wafers, and freely rotating Fe{sub 2}O{sub 3} nanoparticles demonstrated the utility of the reactor for a multitude of processes. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to characterize the surface of the substrates prior to and after plasma deposition, and scanning electron microscopy was used to verify that no extensive change in the size or shape of the nanoparticles occurred because of the rotating motion of the reactor. The reactor design was also extended to a non-depositing NH{sub 3} plasma modification system to demonstrate the reactor design is effective for multiple plasma processes.

  2. 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.

  3. RF Gun cavities cooling regime study. K. Floettmann1

    E-Print Network [OSTI]

    RF power of Pa 68kW corre- sponds to a heat load of 300kW m . To remove such a high heat value from of RF fields in the cavity at an operating frequency is calculated in the usual way. The temperature) with the boundary condition at the RF cavity surface: kc(ngradT) = Ps, (2) where kc = 391 W m·K is the heat

  4. 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.

  5. Rf Feedback free electron laser

    DOE Patents [OSTI]

    Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  6. RF properties of periodic accelerating structures for linear colliders

    SciTech Connect (OSTI)

    Wang, J.W.

    1989-07-01T23:59:59.000Z

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

  7. 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

  8. 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.

  9. RF cavity using liquid dielectric for tuning and cooling

    DOE Patents [OSTI]

    Popovic, Milorad (Warrenville, IL); Johnson, Rolland P. (Newport News, VA)

    2012-04-17T23:59:59.000Z

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  10. ENHANCING NETWORK SECURITY USING 'LEARNING-FROM-SIGNALS' AND FRACTIONAL FOURIER TRANSFORM BASED RF-DNA FINGERPRINTS

    SciTech Connect (OSTI)

    Buckner, Mark A [ORNL; Bobrek, Miljko [ORNL; Farquhar, Ethan [ORNL; Harmer, Paul K [Air Force Institute of Technology; Temple, Michael A [Air Force Institute of Technology

    2011-01-01T23:59:59.000Z

    Wireless Access Points (WAP) remain one of the top 10 network security threats. This research is part of an effort to develop a physical (PHY) layer aware Radio Frequency (RF) air monitoring system with multi-factor authentication to provide a first-line of defense for network security--stopping attackers before they can gain access to critical infrastructure networks through vulnerable WAPs. This paper presents early results on the identification of OFDM-based 802.11a WiFi devices using RF Distinct Native Attribute (RF-DNA) fingerprints produced by the Fractional Fourier Transform (FRFT). These fingerprints are input to a "Learning from Signals" (LFS) classifier which uses hybrid Differential Evolution/Conjugate Gradient (DECG) optimization to determine the optimal features for a low-rank model to be used for future predictions. Results are presented for devices under the most challenging conditions of intra-manufacturer classification, i.e., same-manufacturer, same-model, differing only in serial number. The results of Fractional Fourier Domain (FRFD) RF-DNA fingerprints demonstrate significant improvement over results based on Time Domain (TD), Spectral Domain (SD) and even Wavelet Domain (WD) fingerprints.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. PUBLISHED VERSION RF contact development for the ITER ICRH antenna

    E-Print Network [OSTI]

    Cyclotron (IC) antenna design, ITER Organization requested qualification tests on sliding Radio contacts in relevant conditions (2.25kA @ 62.5MHz, vacuum pressure detailed with RF power tests for long shot duration (1000s) under vacuum and extensive sliding tests

  18. RF signal inductors in iUHD for voltage controlled oscillators in configurable RF integrated circuits

    E-Print Network [OSTI]

    Karpe, Charvak (Charvak P.)

    2006-01-01T23:59:59.000Z

    The miniaturization of radio frequency wireless communications circuitry has resulted in a need for smaller inductors. This thesis presents designs of spiral inductors to be fabricated in Draper Laboratory's integrated ...

  19. Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation

    SciTech Connect (OSTI)

    Stratakis, D.; Gallardo, J.; Palmer, R.B.

    2011-03-28T23:59:59.000Z

    Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Our results agree with current experimental data. Two specific examples illustrate the implementation of magnetic insulation into prospective particle accelerator applications. The ultimate goal of several research efforts is to integrate high-gradient radio-frequency (rf) structures into next generation particle accelerators. For instance, the Muon Accelerator Program is looking at developing low-frequency cavities for muon cooling, and the International Linear Collider is optimizing the performance of 1.3 GHz rf structures aimed at designing a 1 TeV electron-positron collider. Furthermore, the High Gradient RF Collaboration is examining high frequency (f > 10 GHz) structures intended for an electron-positron collider operating at energies in the TeV range. In all this research, the accelerating gradient will be one of the crucial parameters affecting their design, construction, and cost. Limitations from rf breakdown strongly influence the development of accelerators since it limits the machine's maximum gradient. The emission of electrons from the cavity surfaces seemingly is a necessary stage in the breakdown process, acting either as a direct cause of breakdown or as precursor for other secondary effects. Typically, electron currents arise from sharp edges or cracks on the cavities surfaces, where the strength of the electric field is strongly enhanced compared to that of the nominal field when the surfaces of the cavity are perfect planes. Subsequently, a stream of emitted electrons can be accelerated by the rf electric field toward the opposing cavity walls. Upon impact, they heat a localized region, resulting in the eventual breakdown by a variety of secondary mechanisms. Therefore, it is advantageous to develop techniques that could suppress field emission within rf cavities. It has been proposed that high voltages up to about a gigavolt range may be sustained in voltage transformers, by adopting the principle of magnetic insulation in ultrahigh vacuum. The basic idea is to suppress field emission by applying a suitably directed magnetic field of sufficient strength to force the electrons orbits back on to the rf emitting surface. More recently, it was shown that magnetic insulation could be very effective in suppressing field emission and multipacting in rectangular coupler waveguides. Hence, the question arises whether the same principle is applicable to rf accelerating structures. In this Letter, we shall consider application of the concept to low-frequency (201-805 MHz) muon accelerator cavities.

  20. 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

  1. Investigation of Microscopic Materials Limitations of Superconducting RF Cavities

    SciTech Connect (OSTI)

    Anlage, Steven [University of Maryland

    2014-07-23T23:59:59.000Z

    The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.

  2. Evaluation of a RF-Based Approach for Tracking UF6 Cylinders at a Uranium Enrichment Plant

    SciTech Connect (OSTI)

    Pickett, Chris A [ORNL] [ORNL; Younkin, James R [ORNL] [ORNL; Kovacic, Donald N [ORNL] [ORNL; Laughter, Mark D [ORNL] [ORNL; Hines, Jairus B [ORNL] [ORNL; Boyer, Brian [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Martinez, B. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL)

    2008-01-01T23:59:59.000Z

    Approved industry-standard cylinders are used globally to handle and store uranium hexafluoride (UF{sub 6}) feed, product, tails, and samples at uranium enrichment plants. The International Atomic Energy Agency (IAEA) relies on time-consuming physical inspections to verify operator declarations and detect possible diversion of UF{sub 6}. Development of a reliable, automated, and tamper-resistant system for near real-time tracking and monitoring UF{sub 6} cylinders (as they move within an enrichment facility) would greatly improve the inspector function. This type of system can reduce the risk of false or misreported cylinder tare weights, diversion of nuclear material, concealment of excess production, utilization of undeclared cylinders, and misrepresentation of the cylinders contents. This paper will describe a proof-of-concept approach that was designed to evaluate the feasibility of using radio frequency (RF)-based technologies to track individual UF{sub 6} cylinders throughout a portion of their life cycle, and thus demonstrate the potential for improved domestic accountability of materials, and a more effective and efficient method for application of site-level IAEA safeguards. The evaluation system incorporates RF-based identification devices (RFID) which provide a foundation for establishing a reliable, automated, and near real-time tracking system that can be set up to utilize site-specific, rules-based detection algorithms. This paper will report results from a proof-of-concept demonstration at a real enrichment facility that is specifically designed to evaluate both the feasibility of using RF to track cylinders and the durability of the RF equipment to survive the rigors of operational processing and handling. The paper also discusses methods for securely attaching RF devices and describes how the technology can effectively be layered with other safeguard systems and approaches to build a robust system for detecting cylinder diversion. Additionally, concepts for off-site tracking of cylinders are described.

  3. Response of colliding beam-beam system to harmonic excitation due to crab-cavity rf phase modulation

    E-Print Network [OSTI]

    Ohmi, K; Funakoshi, Y; Calaga, R; Ieiri, T; Morita, Y; Nakanishi, K; Oide, K; Ohnishi, Y; Sun, Y; Tobiyama, M; Zimmermann, F; 10.1103/PhysRevSTAB.14.111003

    2011-01-01T23:59:59.000Z

    During 2008 and 2009 dedicated beam experiments with crab cavities were performed in the KEKB. The goal was to measure the impact of crab-cavity radio frequency (rf ) noise on the beam quality. These experiments were performed as a validation of the crab-cavity beam dynamics models in view of the possible use of crab cavities in the upgrade of the CERN Large Hadron Collider (LHC). An unexpected strong beam-beam instability was observed during the course of the experiments as a kind of frequency response. Understanding this finding required extensive multiparticle and single particle simulations plus an extra experimental session to consolidate the observations. Published in PRST-AB 14:111003 (2011)

  4. 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.

  5. RADIO CONTROL CRICKET V2.0

    E-Print Network [OSTI]

    5 5 4 4 3 3 2 2 1 1 D D C C B B A A PCLK PDATA PALE RADIO DATA SPI_SCK SPI_MOSI SPI_MISO CHP_SCK PCLK PDATA PALE ADC0 SPI_MISO CHP_OUT RF_DETECT AVCC AVCC VCC VCC AVCC VCC AVCC VCC VCC VCC J9 HDR 2 X AVCC AVCC AVCC AVCC RF_IN RF_OUT L1 L2 CHP_OUT R_BIAS XOSC1 XOSC2 DIO DCLK PCLK PDATA PALE RSSI C18 R13

  6. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    SciTech Connect (OSTI)

    Johnson, Rolland

    2014-09-21T23:59:59.000Z

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.

  7. 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...

  8. Design and RF measurements of a 5 GHz 500 kW window for the ITER LHCD system

    E-Print Network [OSTI]

    Hillairet, Julien; Dechambre, N; Delpech, L; Ekedahl, A; Faure, N; Goniche, M; Kim, J; Larroque, S; Magne, R; Marfisi, L; Namkung, W; Park, H; Park, S; Poli, S; Vulliez, K

    2015-01-01T23:59:59.000Z

    CEA/IRFM is conducting R\\&D efforts in order to validate the critical RF components of the 5 GHz ITER LHCD system, which is expected to transmit 20 MW of RF power to the plasma. Two 5 GHz 500 kW BeO pill-box type window prototypes have been manufactured in 2012 by the PMB Company, in close collaboration with CEA/IRFM. Both windows have been validated at low power, showing good agreement between measured and modeling, with a return loss better than 32 dB and an insertion loss below 0.05 dB. This paper reports on the window RF design and the low power measurements. The high power tests up to 500kW have been carried out in March 2013 in collaboration with NFRI. Results of these tests are also reported. In the current ITER LHCD design, 20 MW Continuous Wave (CW) of Radio-Frequency power at 5 GHz are expected to be generated and transmitted to the plasma. In order to separate the vacuum vessel pressure from the cryostat waveguide pressure, forty eight 5 GHz 500kW CW windows are to be assembled on the waveguide...

  9. Broadband RF Front-End Design for Multi-Standard Receiver with High-Linearity and Low-Noise Techniques

    E-Print Network [OSTI]

    Kim, Ju Sung

    2012-02-14T23:59:59.000Z

    Future wireless communication devices must support multiple standards and features on a single-chip. The trend towards software-defined radio requires flexible and efficient RF building blocks which justifies the adoption of broadband receiver front...

  10. 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.

  11. Rf System Requirements for JLab’s MEIC Collider Ring

    SciTech Connect (OSTI)

    Wang, Shaoheng [JLAB; Li, Rui [JLAB; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB; Zhang, Yuhong [JLAB

    2013-06-01T23:59:59.000Z

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. At the top energy are the electron and ion collider rings. For the ion ring, it accelerates five long ion bunches to colliding energy and rebunches ions into a train of very short bunches before colliding. A set of low frequency RF system is needed for the long ion bunch energy ramping. Another set of high frequency RF cavities is needed to rebunch ions. For the electron ring, superconducting RF (SRF) cavities are needed to compensate the synchrotron radiation energy loss. The impedance of the SRF cavities must be low enough to keep the high current electron beam stable. The preliminary design requirements of these RF cavities are presented.

  12. 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.

  13. A compact 10 kW, 476 MHz solid state radio frequency amplifier for pre-buncher cavity of free electron laser injector linear accelerator

    SciTech Connect (OSTI)

    Mohania, Praveen; Mahawar, Ashish; Shrivastava, Purushottam; Gupta, P. D. [Raja Rammana Centre for Advanced Technology (RRCAT), Indore 452013 (India)] [Raja Rammana Centre for Advanced Technology (RRCAT), Indore 452013 (India)

    2013-09-15T23:59:59.000Z

    A 10 kW, 476 MHz, 0.1% duty cycle solid state RF amplifier system for driving sub-harmonic, pre-buncher cavity of IR-FEL injector LINAC, has been developed at RRCAT. The 10 kW power is achieved by combining output of eight 1400 W amplifier modules using 8-way planar corporate combiner. The solid state amplifier modules have been developed using 50 V RF LDMOS transistors which although meant for push-pull operation are being used in single ended configuration with matching circuit developed on a thin (25 mils), high dielectric constant (9.7), low loss microwave laminate with an aim to have a compact structure. Ease of fabrication, modularity, small size, and low cost are the important features of this design which could be used as a template for low duty cycle medium to high pulsed power UHF amplifier system.

  14. Photonic RF oscillator based on monolithic DFB lasers with

    E-Print Network [OSTI]

    Boyer, Edmond

    Photonic RF oscillator based on monolithic DFB lasers with frequency-shifted feedback L. Wang, M by using monolithic dual-wavelength DFB semiconductor lasers submitted to a frequency-shifted optical. Dashed line: Lorentzian fit. (a) Free running, RBW: 30 kHz, span: 50 MHz. (b) With feedback, RBW: 1Hz

  15. RF test bench automation Description

    E-Print Network [OSTI]

    Dobigeon, Nicolas

    RF test bench automation Description: Callisto would like to implement automated RF test bench. Three RF test benches have to be studied and automated: LNA noise temperature test bench LNA gain phase of the test benches and an implementation of the automation phase. Tasks: Noise temperature

  16. A Survey of Pressure Vessel Code Compliance for Superconducting RF Cryomodules

    SciTech Connect (OSTI)

    Peterson, Thomas; Klebaner, Arkadiy; Nicol, Tom; Theilacker, Jay; /Fermilab; Hayano, Hitoshi; Kako, Eiji; Nakai, Hirotaka; Yamamoto, Akira; /KEK, Tsukuba; Jensch, Kay; Matheisen, Axel; /DESY; Mammosser, John; /Jefferson Lab

    2011-06-07T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities made from niobium and cooled with liquid helium are becoming key components of many particle accelerators. The helium vessels surrounding the RF cavities, portions of the niobium cavities themselves, and also possibly the vacuum vessels containing these assemblies, generally fall under the scope of local and national pressure vessel codes. In the U.S., Department of Energy rules require national laboratories to follow national consensus pressure vessel standards or to show ''a level of safety greater than or equal to'' that of the applicable standard. Thus, while used for its superconducting properties, niobium ends up being treated as a low-temperature pressure vessel material. Niobium material is not a code listed material and therefore requires the designer to understand the mechanical properties for material used in each pressure vessel fabrication; compliance with pressure vessel codes therefore becomes a problem. This report summarizes the approaches that various institutions have taken in order to bring superconducting RF cryomodules into compliance with pressure vessel codes. In Japan, Germany, and the U.S., institutions building superconducting RF cavities integrated in helium vessels or procuring them from vendors have had to deal with pressure vessel requirements being applied to SRF vessels, including the niobium and niobium-titanium components of the vessels. While niobium is not an approved pressure vessel material, data from tests of material samples provide information to set allowable stresses. By means of procedures which include adherence to code welding procedures, maintaining material and fabrication records, and detailed analyses of peak stresses in the vessels, or treatment of the vacuum vessel as the pressure boundary, research laboratories around the world have found methods to demonstrate and document a level of safety equivalent to the applicable pressure vessel codes.

  17. A "Proof-of-Concept" Demonstration of RF-Based Technologies for UF6 Cylinder Tracking at Centrifuge Enrichment Plant

    SciTech Connect (OSTI)

    Pickett, Chris A [ORNL] [ORNL; Younkin, James R [ORNL] [ORNL; Kovacic, Donald N [ORNL] [ORNL; Dixon, E. T. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Martinez, B. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL)

    2007-01-01T23:59:59.000Z

    This effort describes how radio-frequency (RF) technology can be integrated into a uranium enrichment facility's nuclear materials accounting and control program to enhance uranium hexafluoride (UF6) cylinder tracking and thus provide benefits to both domestic and international safeguards. Approved industry-standard cylinders are used to handle and store UF6 feed, product, tails, and samples at uranium enrichment plants. In the international arena, the International Atomic Energy Agency (IAEA) relies on time-consuming manual cylinder inventory and tracking techniques to verify operator declarations and to detect potential diversion of UF6. Development of a reliable, automated, and tamper-resistant process for tracking and monitoring UF6 cylinders would greatly reduce the risk of false or misreported cylinder tare weights, diversion of nuclear material, concealment of excess production, utilization of undeclared cylinders, and misrepresentation of the cylinders contents. This paper will describe a "proof-of concept" system that was designed show the feasibility of using RF based technologies to track individual UF6 cylinders throughout their entire life cycle, and thus ensure both increased domestic accountability of materials and a more effective and efficient method for application of IAEA international safeguards at the site level. The proposed system incorporates RF-based identification devices, which provide a mechanism for a reliable, automated, and tamper-resistant tracking network. We explore how securely attached RF tags can be integrated with other safeguards technologies to better detect diversion of cylinders. The tracking system could also provide a foundation for integration of other types of safeguards that would further enhance detection of undeclared activities.

  18. Modeling, simulation, and testing of the mechanical dynamics of and RF MEMS switch.

    SciTech Connect (OSTI)

    Sumali, Hartono; Epp, David S.; Massad, Jordan Elias; Dyck, Christopher William; Starr, Michael James

    2005-07-01T23:59:59.000Z

    Mechanical dynamics can be a determining factor for the switching speed of radio-frequency microelectromechanical systems (RF MEMS) switches. This paper presents the simulation of the mechanical motion of a microswitch under actuation. The switch has a plate suspended by springs. When an electrostatic actuation is applied, the plate moves toward the substrate and closes the switch. Simulations are calculated via a high-fidelity finite element model that couples solid dynamics with electrostatic actuation. It incorporates non-linear coupled dynamics and accommodates fabrication variations. Experimental modal analysis gives results in the frequency domain that verifies the natural frequencies and mode shapes predicted by the model. An effective 1D model is created and used to calculate an actuation voltage waveform that minimizes switch velocity at closure. In the experiment, the switch is actuated with this actuation voltage, and the displacements of the switch at various points are measured using a laser Doppler velocimeter through a microscope. The experiments are repeated on several switches from different batches. The experimental results verify the model.

  19. RF propagation in an HVAC duct system: impulse response characteristics of the channel

    E-Print Network [OSTI]

    Stancil, Daniel D.

    RF propagation in an HVAC duct system: impulse response characteristics of the channel Pavel V, the heating, ventilation, and air conditioning (HVAC) duct system in buildings is a complex network of hollow at RF and microwave frequencies of com- mon interest. HVAC ducts can be used as a wireless communication

  20. TRANSIENT NUMERICAL STUDY OF TEMPERATURE GRADIENTS DURING SUBLIMATION GROWTH OF SiC

    E-Print Network [OSTI]

    mathematical heat transfer model including heat conduction, radiation, and radio frequency (RF) induction

  1. The MUCOOL RF Program

    SciTech Connect (OSTI)

    Norem, J.; /Argonne; Bross, A.; Moretti, A.; Norris, B.; Qian, Z.; /Fermilab; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Li, D.; Virostek, S.; Zisman, M.; /LBL,; Sandstrom, R.; /Geneva U.

    2006-06-26T23:59:59.000Z

    Efficient muon cooling requires high RF gradients in the presence of high (3T) solenoidal fields. The Muon Ionization Cooling Experiment (MICE) also requires that the x-ray production from these cavities is low, in order to minimize backgrounds in the particle detectors that must be located near the cavities. These cavities require thin Be windows to ensure the highest fields on the beam axis. In order to develop these cavities, the MUCOOL RF Program was started about 6 years ago. Initial measurements were made on a six-cell cavity and a single-cell pillbox, both operating at 805 MHz. We have now begun measurements of a 201 MHz pillbox cavity. This program has led to new techniques to look at dark currents, a new model for breakdown and a general model of cavity performance based on surface damage. The experimental program includes studies of thin Be windows, conditioning, dark current production from different materials, magnetic-field effects and breakdown.

  2. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources 

    E-Print Network [OSTI]

    Kurpad, Krishna Nagaraj

    2005-11-01T23:59:59.000Z

    The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the ...

  3. High Power RF Test Facility at the SNS

    SciTech Connect (OSTI)

    Y.W. Kang; D.E. Anderson; I.E. Campisi; M. Champion; M.T. Crofford; R.E. Fuja; P.A. Gurd; S. Hasan; K.-U. Kasemir; M.P. McCarthy; D. Stout; J.Y. Tang; A.V. Vassioutchenko; M. Wezensky; G.K. Davis; M. A. Drury; T. Powers; M. Stirbet

    2005-05-16T23:59:59.000Z

    RF Test Facility has been completed in the SNS project at ORNL to support test and conditioning operation of RF subsystems and components. The system consists of two transmitters for two klystrons powered by a common high voltage pulsed converter modulator that can provide power to two independent RF systems. The waveguides are configured with WR2100 and WR1150 sizes for presently used frequencies: 402.5 MHz and 805 MHz. Both 402.5 MHz and 805 MHz systems have circulator protected klystrons that can be powered by the modulator capable of delivering 11 MW peak and 1 MW average power. The facility has been equipped with computer control for various RF processing and complete dual frequency operation. More than forty 805 MHz fundamental power couplers for the SNS superconducting linac (SCL) cavities have been RF conditioned in this facility. The facility provides more than 1000 ft2 floor area for various test setups. The facility also has a shielded cave area that can support high power tests of normal conducting and superconducting accelerating cavities and components.

  4. 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.

  5. High-Efficiency Resonant RF Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams

    E-Print Network [OSTI]

    P. -N. Seo; L. Barron-Palos; J. D. Bowman; T. E. Chupp; C. Crawford; M. Dabaghyan; M. Dawkins; S. J. Freedman; T. Gentile; M. T. Gericke; R. C. Gillis; G. L. Greene; F. W. Hersman; G. L. Jones; M. Kandes; S. Lamoreaux; B. Lauss; M. B. Leuschner; R. Mahurin; M. Mason; J. Mei; G. S. Mitchell; H. Nann; S. A. Page; S. I. Penttila; W. D. Ramsay; A. Salas Bacci; S. Santra; M. Sharma; T. B. Smith; W. M. Snow; W. S. Wilburn; H. Zhu

    2007-10-15T23:59:59.000Z

    We have developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to RF neutron spin flippers based on adiabatic fast passage. The spin rotator does not change the kinetic energy of the neutrons and leaves the neutron beam phase space unchanged to high precision. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically-polarized 3He neutron spin filters. The efficiency of the spin rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from 3.3 to 18.4 meV over the full phase space of the beam. As an example of the application of this device to an experiment we describe the integration of the RF spin rotator into an apparatus to search for the small parity-violating asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the NPDGamma collaboration at LANSCE.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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...

  11. 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.

  12. 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.

  13. RF-Plasma Source Commissioning in Indian Negative Ion Facility

    SciTech Connect (OSTI)

    Singh, M. J.; Bandyopadhyay, M.; Yadava, Ratnakar; Chakraborty, A. K. [ITER- India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujrat (India); Bansal, G.; Gahlaut, A.; Soni, J.; Kumar, Sunil; Pandya, K.; Parmar, K. G.; Sonara, J. [Institute for Plasma Research, Bhat Gandhinagar, Gujrat (India); Kraus, W.; Heinemann, B.; Riedl, R.; Obermayer, S.; Martens, C.; Franzen, P.; Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2011-09-26T23:59:59.000Z

    The Indian program of the RF based negative ion source has started off with the commissioning of ROBIN, the inductively coupled RF based negative ion source facility under establishment at Institute for Plasma research (IPR), India. The facility is being developed under a technology transfer agreement with IPP Garching. It consists of a single RF driver based beam source (BATMAN replica) coupled to a 100 kW, 1 MHz RF generator with a self excited oscillator, through a matching network, for plasma production and ion extraction and acceleration. The delivery of the RF generator and the RF plasma source without the accelerator, has enabled initiation of plasma production experiments. The recent experimental campaign has established the matching circuit parameters that result in plasma production with density in the range of 0.5-1x10{sup 18}/m{sup 3}, at operational gas pressures ranging between 0.4-1 Pa. Various configurations of the matching network have been experimented upon to obtain a stable operation of the set up for RF powers ranging between 25-85 kW and pulse lengths ranging between 4-20 s. It has been observed that the range of the parameters of the matching circuit, over which the frequency of the power supply is stable, is narrow and further experiments with increased number of turns in the coil are in the pipeline to see if the range can be widened. In this paper, the description of the experimental system and the commissioning data related to the optimisation of the various parameters of the matching network, to obtain stable plasma of required density, are presented and discussed.

  14. Unbalanced field RF electron gun

    DOE Patents [OSTI]

    Hofler, Alicia

    2013-11-12T23:59:59.000Z

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  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. Software-defined Radio Based Wireless Tomography: Experimental Demonstration and Verification

    SciTech Connect (OSTI)

    Bonior, Jason D [ORNL; Hu, Zhen [Tennessee Technological University; Guo, Terry N. [Tennessee Technological University; Qiu, Robert C. [Tennessee Technological University; Browning, James P. [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Wicks, Michael C. [University of Dayton Research Institute

    2015-01-01T23:59:59.000Z

    This letter presents an experimental demonstration of software-defined-radio-based wireless tomography using computer-hosted radio devices called Universal Software Radio Peripheral (USRP). This experimental brief follows our vision and previous theoretical study of wireless tomography that combines wireless communication and RF tomography to provide a novel approach to remote sensing. Automatic data acquisition is performed inside an RF anechoic chamber. Semidefinite relaxation is used for phase retrieval, and the Born iterative method is utilized for imaging the target. Experimental results are presented, validating our vision of wireless tomography.

  18. 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.

  19. 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.

  20. Cryogenic vacuumm RF feedthrough device

    DOE Patents [OSTI]

    Wu, Genfa (Yorktown, VA); Phillips, Harry Lawrence (Hayes, VA)

    2008-12-30T23:59:59.000Z

    A cryogenic vacuum rf feedthrough device comprising: 1) a probe for insertion into a particle beam; 2) a coaxial cable comprising an inner conductor and an outer conductor, a dielectric/insulating layer surrounding the inner conductor, the latter being connected to the probe for the transmission of higher mode rf energy from the probe; and 3) a high thermal conductivity stub attached to the coaxial dielectric about and in thermal contact with the inner conductor which high thermal conductivity stub transmits heat generated in the vicinity of the probe efficiently and radially from the area of the probe and inner conductor all while maintaining useful rf transmission line characteristics between the inner and outer coaxial conductors.

  1. New low-level rf system for the Fermilab Booster synchrotron

    SciTech Connect (OSTI)

    Kerns, C.; Crisp, J.; Kerns, Q.; Miller, H.

    1987-03-01T23:59:59.000Z

    This paper describes the Booster low-level rf system that was constructed to meet these recently added requirements: (1) synthesizer controlled capture frequency at injection, (2) very low-phase noise over the machine cycle, (3) smooth phase-lock of beam to an external reference frequency and (4) ability to accelerate either a full turn or partial turn of beam.

  2. Solid state RF power: The route to 1W per euro cent

    SciTech Connect (OSTI)

    Heid, Oliver [Siemens AG, Mozartstrasse 57, Erlangen (Germany)

    2013-04-19T23:59:59.000Z

    In most particle accelerators RF power is a decisive design constraint due to high costs and relative inflexibility of current electron beam based RF sources, i.e. Klystrons, Magnetrons, Tetrodes etc. At VHF/UHF frequencies the transition to solid state devices promises to fundamentally change the situation. Recent progress brings 1 Watt per Euro cent installed cost within reach. We present a Silicon Carbide semiconductor solution utilising the Solid State Direct Drive technology at unprecedented efficiency, power levels and power densities. The proposed solution allows retrofitting of existing RF accelerators and opens the route to novel particle accelerator concepts.

  3. 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 ...

  4. advanced rf gun: Topics by E-print Network

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

    attached to the RF gun is shown in Fig. 1. The RF gun is an L-band 1 12- cell RF gun 4 TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities Physics...

  5. 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

  6. 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...

  7. 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...

  8. 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 ...

  9. 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.

  10. 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.

  11. 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).

  12. Stepped frequency ground penetrating radar

    DOE Patents [OSTI]

    Vadnais, Kenneth G. (Ojai, CA); Bashforth, Michael B. (Buellton, CA); Lewallen, Tricia S. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA)

    1994-01-01T23:59:59.000Z

    A stepped frequency ground penetrating radar system is described comprising an RF signal generating section capable of producing stepped frequency signals in spaced and equal increments of time and frequency over a preselected bandwidth which serves as a common RF signal source for both a transmit portion and a receive portion of the system. In the transmit portion of the system the signal is processed into in-phase and quadrature signals which are then amplified and then transmitted toward a target. The reflected signals from the target are then received by a receive antenna and mixed with a reference signal from the common RF signal source in a mixer whose output is then fed through a low pass filter. The DC output, after amplification and demodulation, is digitized and converted into a frequency domain signal by a Fast Fourier Transform. A plot of the frequency domain signals from all of the stepped frequencies broadcast toward and received from the target yields information concerning the range (distance) and cross section (size) of the target.

  13. Constraining the radio-loud fraction of quasars at z>5.5

    E-Print Network [OSTI]

    Bañados, E; Morganson, E; Hodge, J; Decarli, R; Walter, F; Stern, D; Schlafly, E; Farina, E P; Greiner, J; Chambers, K C; Fan, X; Rix, H-W; Burgett, W S; Draper, P W; Flewelling, J; Kaiser, N; Metcalfe, N; Morgan, J S; Tonry, J L; Wainscoat, R J

    2015-01-01T23:59:59.000Z

    Radio-loud Active Galactic Nuclei at z~2-4 are typically located in dense environments and their host galaxies are among the most massive systems at those redshifts, providing key insights for galaxy evolution. Finding radio-loud quasars at the highest accessible redshifts (z~6) is important to study their properties and environments at even earlier cosmic time. They would also serve as background sources for radio surveys intended to study the intergalactic medium beyond the epoch of reionization in HI 21 cm absorption. Currently, only five radio-loud ($R=f_{\

  14. High-power rf-pulsed modulators for the Los Alamos free-electron laser

    SciTech Connect (OSTI)

    Johnson, W.J.D.; Lynch, M.T.; Tallerico, P.J.; Keffeler, D.R.; Hornkohl, J.O.

    1987-09-01T23:59:59.000Z

    In the rf-driven free-electron laser (FEL) at the Los Alamos National Laboratory, there are two pulsed-power rf modulators as sources for two tandem, side-coupled 20-MeV linear accelerators. The rf power used to control the cavity fields is supplied by two 5.5-MW modulating anode klystrons operating at a center frequency of 1300.2 MHz. The modulation of the 125 kV klystron is achieved by using a triode switch tube that provides a pulse width up to 300 ..mu..s and a pulse repetition rate up to 10 Hz. This paper describes the present configuration of these two duplicate systems and presents plans for meeting the requirements of future rf FEL experiments at Los Alamos. 12 refs., 5 figs.

  15. Loading a planar RF Paul Trap from a cold Yb? source

    E-Print Network [OSTI]

    Shields, Brendan John

    2006-01-01T23:59:59.000Z

    In this thesis, we demonstrate a functioning planar radio frequency, three-rod Paul Trap, loaded with Yb+ ions that have been photoionized from a source of neutral atoms, which were cooled in a magneto-optical trap. Planar ...

  16. Single electron beam rf feedback free electron laser

    DOE Patents [OSTI]

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11T23:59:59.000Z

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  17. 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

  18. 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

  19. RF Systems in a Neutrino Factory

    SciTech Connect (OSTI)

    Berg J. S.

    2012-09-07T23:59:59.000Z

    Based on existing sources, I compile parameters for the RF systems for a neutrino factory which accelerates to 10 GeV.

  20. RF/optical shared aperture for high availability wideband communication RF/FSO links

    DOE Patents [OSTI]

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2014-04-29T23:59:59.000Z

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  1. A new microphonics measurement method for superconducting RF cavities

    SciTech Connect (OSTI)

    Gao,Zheng; He,Yuan; Chang,Wei; Powers, Tom [JLAB; Yue,Wei-ming; Zhu,Zheng-long; Chen,Qi

    2014-09-01T23:59:59.000Z

    Mechanical vibrations of the superconducting cavity, also known as microphonics, cause shifts in the resonant frequency of the cavity. In addition to requiring additional RF power, these frequency shifts can contribute to errors in the closed loop phase and amplitude regulation. In order to better understand these effects, a new microphonics measurement method was developed, and the method was successfully used to measure microphonics on the half-wave superconducting cavity when it was operated in a production style cryostat. The test cryostat held a single ?=0.1 half-wave cavity which was operated at 162.5 MHz [1] and [2]. It's the first time that the National Instruments PXIe-5641R intermediate frequency transceiver has been used for microphonics measurements in superconducting cavities. The new microphonics measurement method and results will be shown and analyzed in this paper.

  2. National RF Test Facility as a multipurpose development tool

    SciTech Connect (OSTI)

    McManamy, T.J.; Becraft, W.R.; Berry, L.A.; Blue, C.W.; Gardner, W.L.; Haselton, H.H.; Hoffman, D.J.; Loring, C.M. Jr.; Moeller, F.A.; Ponte, N.S.

    1983-01-01T23:59:59.000Z

    Additions and modifications to the National RF Test Facility design have been made that (1) focus its use for technology development for future large systems in the ion cyclotron range of frequencies (ICRF), (2) expand its applicability to technology development in the electron cyclotron range of frequencies (ECRF) at 60 GHz, (3) provide a facility for ELMO Bumpy Torus (EBT) 60-GHz ring physics studies, and (4) permit engineering studies of steady-state plasma systems, including superconducting magnet performance, vacuum vessel heat flux removal, and microwave protection. The facility will continue to function as a test bed for generic technology developments for ICRF and the lower hybrid range of frequencies (LHRF). The upgraded facility is also suitable for mirror halo physics experiments.

  3. Kinetics of plasma electrons in static and rf fields

    SciTech Connect (OSTI)

    Ivanov, Y.A.; Lebedev, Y.A.; Polak, L.S.

    1980-01-01T23:59:59.000Z

    The effect of the frequency of the field producing a plasma on the isotropic part of the electron energy distribution is analyzed. Analytic solutions of the Boltzmann equation are derived for high-energy tail of the electron energy distribution for static and rf fields. The results show that the shape of the tail of the distribution can be effectively controlled by changing the ratio of the field frequency to the effective frequency with which electrons collide with heavy particles and by choosing the appropriate dependence of the cross section for elastic scattering of electrons by heavy particles on the electron energy (by appropriate choice of the gas from which the plasma is formed). These results agree with experimental results in the literature.

  4. Predictions of microwavePredictions of microwave breakdown in rf structuresbreakdown in rf structures

    E-Print Network [OSTI]

    Yu, Ming

    Predictions of microwave breakdownPredictions of microwave breakdown in rf structuresin rf structures #12;2 of the breakdown phenomenon). 2. Electron interaction with microwave field (rough estimates of parameters which in communication systems Predictions of microwave breakdown in rf structuresPredictions of microwave breakdown

  5. A brief history of high power RF proton linear accelerators

    SciTech Connect (OSTI)

    Browne, J.C.

    1996-12-31T23:59:59.000Z

    The first mention of linear acceleration was in a paper by G. Ising in 1924 in which he postulated the acceleration of positive ions induced by spark discharges which produced electric fields in gaps between a series of {open_quotes}drift tubes{close_quotes}. Ising apparently was not able to demonstrate his concept, most likely due to the limited state of electronic devices. Ising`s work was followed by a seminal paper by R. Wideroe in 1928 in which he demonstrated the first linear accelerator. Wideroe was able to accelerate sodium or potassium ions to 50 keV of energy using drift tubes connected alternately to high frequency waves and to ground. Nuclear physics during this period was interested in accelerating protons, deuterons, electrons and alpha particles and not heavy ions like sodium or potassium. To accelerate the light ions required much higher frequencies than available at that time. So linear accelerators were not pursued heavily at that time. Research continued during the 1930s but the development of high frequency RF tubes for radar applications in World War 2 opened the potential for RF linear accelerators after the war. The Berkeley laboratory of E. 0. Lawrence under the leadership of Luis Alvarez developed a new linear proton accelerator concept that utilized drift tubes that required a full RF period to pass through as compared to the earlier concepts. This development resulted in the historic Berkeley 32 MeV proton linear accelerator which incorporated the {open_quotes}Alvarez drift tube{close_quotes} as the basic acceleration scheme using surplus 200 MHz radar components.

  6. 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...

  7. CAD OF MICROWAVE OPTICAL SYSTEMS FOR TIME&FREQUENCY APPLICATIONS

    E-Print Network [OSTI]

    Boyer, Edmond

    or their impact on the phase noise. II- SIMULATION OF AN MZ BASED OPTICAL LINK: RF GAIN Microwave circuit designCAD OF MICROWAVE OPTICAL SYSTEMS FOR TIME&FREQUENCY APPLICATIONS Houda Brahimi, LAAS-CNRS, Toulouse are more and more involved in time and frequency applications. They may be used for frequency reference

  8. Synthesis and characterization of inorganic silicon oxycarbide glass thin films by reactive rf-magnetron sputtering

    SciTech Connect (OSTI)

    Ryan, Joseph V.; Pantano, C. G.

    2007-01-03T23:59:59.000Z

    Silicon oxycarbide glasses have been of interest because of the potential range of properties they might exhibit through a change in carbon-to-oxygen ratio. They are metastable materials and, as such, their structures and properties are very dependent upon the synthesis method. Silicon oxycarbide bonding has been seen in materials made by melting, oxidation, polycarbosilane or sol/gel pyrolysis, and chemical vapor deposition. In this work, the radio-frequency reactive sputtering of silicon carbide targets was explored for synthesis of amorphous silicon oxycarbide thin films. SiO (2?2x) Cx films, with a continuous range of compositions where 0rf sputtering method is much wider than that of other synthesis methods. It is shown here that for oxygen-to-carbon ratios between *0.10 and 10.0, silicon oxycarbide bonding comprises 55%-95% of the material structure. These sputter-deposited materials were also found to have significantly less free carbon as compared to those produced by other methods. Thus, the unique properties for these novel oxycarbide materials can now be established.

  9. Beam dynamics studies for transverse electromagnetic mode type rf deflectors

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

    Ahmed, Shahid; Krafft, Geoffrey A.; Deitrick, Kirsten; De Silva, Subashini U.; Delayen, Jean R.; Spata, Mike; Tiefenback, Michael; Hofler, Alicia; Beard, Kevin

    2012-02-01T23:59:59.000Z

    We have performed three-dimensional simulations of beam dynamics for transverse electromagnetic mode (TEM) type rf deflectors: normal and superconducting. The compact size of these cavities as compared to the conventional TM110 type structures is more attractive particularly at low frequency. Highly concentrated electromagnetic fields between the parallel bars provide strong electrical stability to the beam for any mechanical disturbance. An array of six 2-cell normal conducting cavities or a single cell superconducting structure is enough to produce the required vertical displacement at the target point. Both the normal and superconducting structures show very small emittance dilution due to the vertical kick of the beam.

  10. RF power recovery feedback circulator

    DOE Patents [OSTI]

    Sharamentov, Sergey I. (Bolingbrook, IL)

    2011-03-29T23:59:59.000Z

    A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

  11. Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method Smail Bachir #1, the nonlinear Internal Model Control (IMC) method is introduced and applied to linearize high frequency Power to be controlled [8]. If the model is a perfect representation of the non linear system, the controller can

  12. A low RF-band impedance spectroscopy based sensor for in-situ, wireless soil sensing

    E-Print Network [OSTI]

    Kumar, Ratnesh

    1 A low RF-band impedance spectroscopy based sensor for in-situ, wireless soil sensing Gunjan of impedance spectroscopy. Impedance measurement at multiple frequencies is done by comparing the amplitude impedance of the board in the measurements to minimize the errors. Measurements of both real and imaginary

  13. RF and Surface Properties of Bulk Niobium and Niobium Film Samples

    E-Print Network [OSTI]

    Junginger, Tobias; Weingarten, Wolfgang

    2012-01-01T23:59:59.000Z

    At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution measurements on bulk niobium and niobium ?lm on copper samples are presented. Surface resistance results are being correlated to surface analyses measurements carried out on the same samples.

  14. Ion transport in macroscopic RF linear traps Jofre Pedregosa-Gutierrez,

    E-Print Network [OSTI]

    Boyer, Edmond

    ´er^ome, 13397 Marseille Cedex 20, France (Dated: July 18, 2014) Abstract Efficient transport of cold atomsIon transport in macroscopic RF linear traps Jofre Pedregosa-Gutierrez, Caroline Champenois, Marius information processing to frequency metrology. Different transport schemes have been developed, which allow

  15. 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.

  16. 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 ...

  17. Bose-Einstein condensates in rf-dressed adiabatic potentials

    SciTech Connect (OSTI)

    White, M.; Gao, H.; Pasienski, M.; DeMarco, B. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2006-08-15T23:59:59.000Z

    Bose-Einstein condensates of {sup 87}Rb atoms are transferred into radio-frequency induced adiabatic potentials and the properties of the corresponding dressed states are explored. We report on measurements of the spin composition of dressed condensates. We also show that adiabatic potentials can be used to trap atom gases in novel geometries, including suspending a cigar-shaped cloud above a curved sheet of atoms.

  18. Linear Gain for the Microbunching Instability in an RF Compressor

    E-Print Network [OSTI]

    Venturini, M.

    2010-01-01T23:59:59.000Z

    Instability in an RF Compressor M. Venturini Lawrencefor investigating this instability in rf compressors. We useapplied to magnetic compressors [2, 3] and derive some

  19. 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

  20. 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

  1. 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

  2. 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_{\

  3. Some new methods of RF control

    SciTech Connect (OSTI)

    Jachim, S.P.

    1990-01-01T23:59:59.000Z

    This presentation will focus on several recent developments at Los Alamos in the area of RF control for accelerators. Included in the discussion will be in-phase/quadrature (I/Q) field control, the application of six-port reflectometers for cavity instrumentation and resonance control, a technique for phase stabilization of critical RF cables, an application of state-variable feedback for field control, and the direct integration of RF and computer-interface hardware using the VXIbus standard. 25 refs., 8 figs.

  4. Design of RF Conditioner Cavities

    E-Print Network [OSTI]

    Govil, R.

    2008-01-01T23:59:59.000Z

    For most designs, the power loss at the cavity surface atheld fixed, the frequency, power loss and a more systematicwhile the cavity power loss (normalized by a factor of four

  5. 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)

  6. Results from a "Proof-of-Concept" Demonstration of RF-Based Tracking of UF6 Cylinders during a Processing Operation at a Uranium Enrichment Plant

    SciTech Connect (OSTI)

    Pickett, Chris A [ORNL] [ORNL; Kovacic, Donald N [ORNL] [ORNL; Whitaker, J Michael [ORNL] [ORNL; Younkin, James R [ORNL] [ORNL; Hines, Jairus B [ORNL] [ORNL; Laughter, Mark D [ORNL] [ORNL; Morgan, Jim [Innovative Solutions] [Innovative Solutions; Carrick, Bernie [USEC] [USEC; Boyer, Brian [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Whittle, K. [USEC] [USEC

    2008-01-01T23:59:59.000Z

    Approved industry-standard cylinders are used globally for processing, storing, and transporting uranium hexafluoride (UF{sub 6}) at uranium enrichment plants. To ensure that cylinder movements at enrichment facilities occur as declared, the International Atomic Energy Agency (IAEA) must conduct time-consuming periodic physical inspections to validate facility records, cylinder identity, and containment. By using a robust system design that includes the capability for real-time unattended monitoring (of cylinder movements), site-specific rules-based event detection algorithms, and the capability to integrate with other types of monitoring technologies, one can build a system that will improve overall inspector effectiveness. This type of monitoring system can provide timely detection of safeguard events that could be used to ensure more timely and appropriate responses by the IAEA. It also could reduce reliance on facility records and have the additional benefit of enhancing domestic safeguards at the installed facilities. This paper will discuss the installation and evaluation of a radio-frequency- (RF-) based cylinder tracking system that was installed at a United States Enrichment Corporation Centrifuge Facility. This system was installed primarily to evaluate the feasibility of using RF technology at a site and the operational durability of the components under harsh processing conditions. The installation included a basic system that is designed to support layering with other safeguard system technologies and that applies fundamental rules-based event processing methodologies. This paper will discuss the fundamental elements of the system design, the results from this site installation, and future efforts needed to make this technology ready for IAEA consideration.

  7. Degreasing and cleaning superconducting RF Niobium cavities

    SciTech Connect (OSTI)

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01T23:59:59.000Z

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  8. Deeply scaled CMOS for RF power applications

    E-Print Network [OSTI]

    Scholvin, Jörg, 1976-

    2006-01-01T23:59:59.000Z

    The microelectronics industry is striving to reduce the cost, complexity, and form factor of wireless systems through single-chip integration of analog, RF and digital functions. Driven by the requirements of the digital ...

  9. Samsung: ENERGY STAR Referral (RF26VAB)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Samsung refrigerator-freezer model RF26VAB to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  10. EXPERIMENTAL STUDIES OF RF BREAKDOWNS IN THE COUPLER OF THE TTF RF GUN

    E-Print Network [OSTI]

    to han- dle 800 µs long RF pulses with 4.5 MW of peak power and at 10 Hz repetition rate. In this regime

  11. 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...

  12. Multipole and field uniformity tailoring of a 750 MHz rf dipole

    SciTech Connect (OSTI)

    Delayen, Jean R. [JLAB, Old Dominion University; Castillo, Alejandro [JLAB, Old Dominion University

    2014-12-01T23:59:59.000Z

    In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependency is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations.

  13. 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

  14. Multi-MW 22.8 GHz Harmonic Multiplier - RF Power Source for High-Gradient Accelerator R&D

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-07-26T23:59:59.000Z

    Electrodynamic and particle simulation studies have been carried out to optimize design of a two-cavity harmonic frequency multiplier, in which a linear electron beam is energized by rotating fields near cyclotron resonance in a TE111 cavity in a uniform magnetic field, and in which the beam then radiates coherently at the nth harmonic into a TEn11 output cavity. Examples are worked out in detail for 7th and 2nd harmonic converters, showing RF-to-RF conversion efficiencies of 45% and 88%, respectively at 19.992 GHz (K-band) and 5.712 GHz (C-band), for a drive frequency of 2.856 GHz. Details are shown of RF infrastructure (S-band klystron, modulator) and harmonic converter components (drive cavity, output cavities, electron beam source and modulator, beam collector) for the two harmonic converters to be tested. Details are also given for the two-frequency (S- and C-band) coherent multi-MW test stand for RF breakdown and RF gun studies.

  15. RF physics of ICWC discharge at high cyclotron harmonics

    SciTech Connect (OSTI)

    Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M. [Association Euratom-Belgian State, LPP-ERM-KMS, 1000 Brussels (Belgium); Bobkov, V.; Rohde, V.; Schneider, P. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Douai, D.; Kogut, D. [Association Euratom-CEA, CEA, IRFM, 13108 St Paul lez Durance (France); Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G. [Association Euratom-IEK-4, Forschungszentrum Jülich, 52425 Jülich (Germany); Moiseenko, V. [Institute of Plasma Physics NSC KIPT, 61108 Kharkiv (Ukraine); Noterdaeme, J.-M. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching, Germany and Ghent University, 9000 Ghent (Belgium); Collaboration: TEXTOR Team; ASDEX Upgrade Team

    2014-02-12T23:59:59.000Z

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,?=?{sub H+}, and with its high cyclotron harmonics (HCH), ?=10?{sub cH+}? HCH scenario: very high antenna coupling to low density RF plasmas (P{sub pl}?0.9P{sub RF-G}) and low energy Maxwellian distribution of CX hydrogen atoms with temperature T{sub H}?350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E{sub ?H} ?1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of B{sub T}-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low T{sub e} plasmas is studied at fundamental ICR and its high harmonics.

  16. Bandwidth scaling and spectral flatness enhancement of optical frequency combs from phase-modulated

    E-Print Network [OSTI]

    Purdue University

    linearly with the RF voltage driving the phase modulator. RF power handling limits the number of lines.g., 200 GHz band- width at 10 GHz drive). To reach the 100 line level, we would have to cascade five a 10 GHz frequency comb with over 100 lines in a 10 dB bandwidth in which a record 75 lines are within

  17. 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

  18. Self isolating high frequency saturable reactor

    DOE Patents [OSTI]

    Moore, James A. (Powell, TN)

    1998-06-23T23:59:59.000Z

    The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

  19. Wideband high efficiency CMOS envelope amplifiers for 4G LTE handset envelope tracking RF power amplifiers

    E-Print Network [OSTI]

    Hassan, Muhammad

    2012-01-01T23:59:59.000Z

    RF power amplifier applications," IEEE Journal of Solid-RF power amplifier applications," IEEE Journal of Solid-RF power amplifier applications," IEEE Journal of Solid-

  20. 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

  1. 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.

  2. Results of a preliminary, high power RF thruster test

    SciTech Connect (OSTI)

    Brewer, L.; Karras, T.; Frind, G.; Holmes, D.G.

    1989-01-01T23:59:59.000Z

    The objective of this program was to demonstrate a high power electrodeless, RF electric propulsion concept. This was successfully accomplished. No attempt was made to optimize the design of the thruster with regard to physical dimensions, mass flow, nozzle shape, operational frequency, or power level. Measurements made were chamber pressure, total and static pressures at the nozzle exit plane and exhaust tank pressure. Mass flows range from about 0.4 to 1 gm/sec and, assuming perfect gas relationships, specific impulses up to 580 sec were obtained. Typical chamber pressure was 300 torr exhausting to a tank pressure of about 10 torr. Working fluids used were argon, helium and mixtures of the two. No degration of the device was detected after 12 start/stop cycles, about three hours of total run time, and a maximum input power of 70 kW. 10 refs.

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. RF design of X-band RF deflector for femtosecond diagnostics of LCLS electron beam

    SciTech Connect (OSTI)

    Dolgashev, Valery A.; Wang Juwen [SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 (United States)

    2012-12-21T23:59:59.000Z

    We designed a successful constant impedance traveling wave X-band rf deflector for electron beam diagnostics at the 14 GeV SLAC Linac Coherent Light Source (LCLS). This is the first practical deflector built with a waveguide coupler. The 1-meter rf deflector produces 24 MeV peak transverse kick when powered with 20 MW of 11.424 GHz rf. The design is based on our experience with high gradient X-band accelerating structures. Several deflectors of this design have been built at SLAC and are currently in use. Here we describe the design and distinguishing features of this device.

  8. Design and fabrication of an RF power LDMOSFET on SOI

    E-Print Network [OSTI]

    Fiorenza, James G. (James George), 1972-

    2002-01-01T23:59:59.000Z

    This thesis studied thin-film Silicon-on-Insulator (SOI) LDMOSFET technology for RF power amplifier applications. To conduct this study, two generations of SOI RF power devices for portable wireless systems were designed ...

  9. analog rf gap: Topics by E-print Network

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

    LHC, particles not captured by the RF system at injection or leaking out of the RF bucket may quench the superconducting magnets during beam abort. The problem, common to other...

  10. 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

  11. Configurations for short period rf undulators

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

    Kuzikov, S. V.; Jiang, Y.; Marshall, T. C.; Sotnikov, G. V.; Hirshfield, J. L.

    2013-07-01T23:59:59.000Z

    Several configurations for rf undulators energized at millimeter wavelengths and designed to produce coherent nanometer radiation from sub-GeV electron beams are analyzed and compared with one another. These configurations include a traveling-wave resonant ring, a standing wave resonator, and a resonator operating close to cutoff.

  12. RF Breakdown of Metallic Surfaces in Hydrogen

    SciTech Connect (OSTI)

    BastaniNejad, M.; Elmustafa, A.A.; /Old Dominion U.; Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia

    2009-05-01T23:59:59.000Z

    In earlier reports, microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments were used to investigate the mechanism of RF breakdown of tungsten, molybdenum, and beryllium electrode surfaces. Plots of remnants were consistent with the breakdown events being due to field emission, due to the quantum mechanical tunnelling of electrons through a barrier as described by Fowler and Nordheim. In the work described here, these studies have been extended to include tin, aluminium, and copper. Contamination of the surfaces, discovered after the experiments concluded, have cast some doubt on the proper qualities to assign to the metallic surfaces. However, two significant results are noted. First, the maximum stable RF gradient of contaminated copper electrodes is higher than for a clean surface. Second, the addition of as little as 0.01% of SF6 to the hydrogen gas increased the maximum stable gradient, which implies that models of RF breakdown in hydrogen gas will be important to the study of metallic breakdown.

  13. RF Design of the LCLS Gun

    SciTech Connect (OSTI)

    Limborg-Deprey, C

    2010-12-13T23:59:59.000Z

    Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell, and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee [2]. Files and reference documents are compiled in Section IV.

  14. Emittance control in rf cavities and solenoids

    E-Print Network [OSTI]

    Eshraqi, Mohammad; Lombardi, Alessandra M

    2009-01-01T23:59:59.000Z

    We study emittance growth for transport of uniform and Gaussian beams of particles in rf cavities and solenoids and show analytically its dependence on initial beam parameters. Analytical results are confirmed with simulation studies over a broad range of different initial beams.

  15. Experimental Study of RF Pulsed Heating

    SciTech Connect (OSTI)

    Laurent, Lisa; Tantawi, Sami; Dolgashev, Valery; Nantista, Christopher; /SLAC; Higashi, Yasuo; /KEK, Tsukuba; Aicheler, Markus; Heikkinen, Samuli; Wuensch, Walter; /CERN

    2011-11-04T23:59:59.000Z

    Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop(reg. sign), copper silver, and silver plated copper. The samples were exposed to different machining and heat treatment processes prior to rf processing. Each sample was tested to a peak pulsed heating temperature of approximately 110 C and remained at this temperature for approximately 10 x 10{sup 6} rf pulses. In general, the results showed the possibility of pushing the gradient limits due to pulsed heating fatigue by the use of copper zirconium and copper chromium alloys.

  16. Commissioning of the MICE RF System

    E-Print Network [OSTI]

    Moss, A.; Stanley, T.; White, C.; Ronald, K.; Whyte, C.G.; Dick, A.J.; Speirs, D.C.; Alsari, S.

    2014-01-01T23:59:59.000Z

    The Muon Ionisation Cooling Experiment (MICE) is being constructed at Rutherford Appleton Laboratory in the UK. The muon beam will be cooled using multiple hydrogen absorbers then reaccelerated using an RF cavity system operating at 201MHz. This paper describes recent progress in commissioning the amplifier systems at their design operation conditions, installation and operation as part of the MICE project.

  17. Advanced RF power sources for linacs

    SciTech Connect (OSTI)

    Wilson, P.B.

    1996-10-01T23:59:59.000Z

    In order to maintain a reasonable over-all length at high center-of-mass energy, the main linac of an electron-positron linear collider must operate at a high accelerating gradient. For copper (non-superconducting) accelerator structures, this implies a high peak power per unit length and a high peak power per RF source, assuming a limited number of discrete sources are used. To provide this power, a number of devices are currently under active development or conceptual consideration: conventional klystrons with multi-cavity output structures, gyroklystrons, magnicons, sheet-beam klystrons, multiple-beam klystrons and amplifiers based on the FEL principle. To enhance the peak power produced by an rf source, the SLED rf pulse compression scheme is currently in use on existing linacs, and new compression methods that produce a flatter output pulse are being considered for future linear colliders. This paper covers the present status and future outlook for the more important rf power sources and pulse compression systems. It should be noted that high gradient electron linacs have applications in addition to high-energy linear colliders; they can, for example, serve as compact injectors for FEL`s and storage rings.

  18. Cw rf operation of the FMIT RFQ

    SciTech Connect (OSTI)

    Fazio, M.V.; Brandeberry, F.E.

    1985-01-01T23:59:59.000Z

    The 80-MHz RFQ for the Fusion Materials Irradiation Test Facility prototype accelerator has been rf conditioned for cw operation to the design field level of 17.5 MV/m (1.68 x Kilpatrick limit). Experimental results and operating experience will be discussed.

  19. 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

  20. Optimal control design of band-selective excitation pulses that accommodate relaxation and RF inhomogeneity

    E-Print Network [OSTI]

    Skinner, Thomas E; Nimbalkar, Manoj; Glaser, Steffen J

    2011-01-01T23:59:59.000Z

    Existing optimal control protocols for mitigating the effects of relaxation and/or RF inhomogeneity on broadband pulse performance are extended to the more difficult problem of designing robust, refocused, frequency selective excitation pulses. For the demanding case of T1 and T2 equal to the pulse length, anticipated signal losses can be significantly reduced while achieving nearly ideal frequency selectivity. Improvements in performance are the result of allowing residual unrefocused magnetization after applying relaxation-compensated selective excitation by optimized pulses (RC-SEBOP). We demonstrate simple pulse sequence elements for eliminating this unwanted residual signal.

  1. 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

  2. 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. ...

  3. 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...

  4. 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

  5. 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.

  6. 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.

  7. 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...

  8. ILC RF System R and D

    SciTech Connect (OSTI)

    Adolphsen, Chris; /SLAC

    2012-07-03T23:59:59.000Z

    The Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system proposed for the ILC linacs. Current activities include the long-term evaluation of a 120 kV Marx Modulator driving a 10 MW Multi-Beam Klystron, design of a second-generation Marx Modulator, testing of a sheet-beam gun and beam transport system for a klystron, construction of an rf distribution system with remotely-adjustable power tapoffs, and development of a system to combine the power from many klystrons in low-loss circular waveguide where it would be tapped-off periodically to power groups of cavities. This paper surveys progress during the past few years.

  9. An Efficient RF Source for Jlab

    SciTech Connect (OSTI)

    Neubauer, M. [Muons, Inc.; Dudas, A. [Muons, Inc.; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB

    2013-12-01T23:59:59.000Z

    We propose the development of a highly reliable high efficiency RF source for JLAB with a lower lifetime cost operating at 80% efficiency with system operating costs of about 0.7M$/year for the 6 GeV machine. The design of the RF source will be based upon two injection locked magnetrons in a novel combining architecture for amplitude modulation and a cross field amplifier (CFA) as an output tube for the 12 GeV upgrade. A cost analysis including efficiency and reliability will be performed to determine the optimum system architecture. Several different system architectures will be designed and evaluated for a dual injection locked magnetron source using novel combining techniques and possibly a CFA as the output tube. A paper design for the 1497 MHz magnetron system will be completed. The optimum system architecture with all relevant specifications will be completed so that a prototype can be built.

  10. RUGGED CERAMIC WINDOW FOR RF APPLICATIONS

    SciTech Connect (OSTI)

    MIKE NEUBAUER

    2012-11-01T23:59:59.000Z

    High-current RF cavities that are needed for many accelerator applications are often limited by the power transmission capability of the pressure barriers (windows) that separate the cavity from the power source. Most efforts to improve RF window design have focused on alumina ceramic, the most popular historical choice, and have not taken advantage of new materials. Alternative window materials have been investigated using a novel Merit Factor comparison and likely candidates have been tested for the material properties which will enable construction in the self-matched window configuration. Window assemblies have also been modeled and fabricated using compressed window techniques which have proven to increase the power handling capability of waveguide windows. Candidate materials have been chosen to be used in fabricating a window for high power testing at Thomas Jefferson National Accelerator Facility.

  11. 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

  12. 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...

  13. RF Gun Photocathode Research at SLAC

    SciTech Connect (OSTI)

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16T23:59:59.000Z

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  14. BROADBAND ANTENNA MATCHING NETWORK DESIGN AND APPLICATION FOR RF PLASMA ION SOURCE

    SciTech Connect (OSTI)

    Shin, Ki [ORNL; Kang, Yoon W [ORNL; Piller, Chip [ORNL; Fathy, Aly [University of Tennessee, Knoxville (UTK)

    2011-01-01T23:59:59.000Z

    The RF ion source at Spallation Neutron Source has been upgraded to meet higher beam power requirement. One important subsystem for efficient operation of the ion source is the 2MHz RF impedance matching network. The real part of the antenna impedance is very small and is affected by plasma density for 2MHz operating frequency. Previous impedance matching network for the antenna has limited tuning capability to cover this potential variation of the antenna impedance since it employed a single tuning element and an impedance transformer. A new matching network with two tunable capacitors has been built and tested. This network can allow precision matching and increase the tunable range without using a transformer. A 5-element broadband matching network also has been designed, built and tested. The 5-element network allows wide band matching up to 50 kHz bandwidth from the resonance center of 2 MHz. The design procedure, simulation and test results are presented.

  15. 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, ...

  16. 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...

  17. 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.

  18. 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

  19. Design and Manufacture of the RF Power Supply and RF Transmission Line for SANAEM Project Prometheus

    E-Print Network [OSTI]

    Turemen, G; Unel, G; Alacakir, A

    2015-01-01T23:59:59.000Z

    A 1-5 MeV proton beamline is being built by the Turkish Atomic Energy Authority in collaboration with a number of graduate students from different universities. The most important aspect of the project, is to acquire the design ability and manufacturing capability of all the components locally. SPP will be an accelerator and beam diagnostics test facility and it will also serve the detector development community with its low beam current. This paper discusses the design and construction of the RF power supply and the RF transmission line components such as its waveguide converters and its circulator.

  20. 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.

  1. 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.

  2. 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

  3. Synthesis of silicon nitride powders in pulsed RF plasmas

    SciTech Connect (OSTI)

    Buss, R.J.; Ho, P. [Sandia National Labs., Albuquerque, NM (United States); Babu, S.V. [Sandia National Labs., Albuquerque, NM (United States)]|[Clarkson Univ., Potsdam, NY (United States). Dept. of Chemical Engineering

    1995-05-01T23:59:59.000Z

    Nanometer size silicon nitride particles are synthesized using a pulsed radio frequency plasma technique. The plasma is modulated with a square-wave on/off cycle of varying period to control size and morphology and to deduce the growth kinetics. In situ laser light scattering and ex situ particle analysis are used to study the nucleation and growth. For SiH{sub 4}/Ar plasmas which nucleate silicon particles, an initial extremely rapid growth phase is followed by a slower growth rate, approaching the rate of thin film deposition on adjacent flat surfaces. In SiH{sub 4}/NH{sub 3} plasmas, silicon nitride particle size can be tightly controlled by adjusting the plasma-on time. The size dispersion of the particles is large and is consistent with a process of continual nucleation during the plasma-on period. The observed polydispersity differs dramatically from that reported from other laboratories.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Using antennas separated in flight direction to avoid effect of emitter clock drift in geolocation

    DOE Patents [OSTI]

    Ormesher, Richard C.; Bickel, Douglas L

    2012-10-23T23:59:59.000Z

    The location of a land-based radio frequency (RF) emitter is determined from an airborne platform. RF signaling is received from the RF emitter via first and second antennas. In response to the received RF signaling, signal samples for both antennas are produced and processed to determine the location of the RF emitter.

  10. argon rf plasma: Topics by E-print Network

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

    you for being so encouraging, for listening to and understanding the woes of RF plasma research, and for being so friendly at conferences and in the hallways. Professor...

  11. Multi-Physics Analysis of the Fermilab Booster RF Cavity

    SciTech Connect (OSTI)

    Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.; /Fermilab

    2012-05-14T23:59:59.000Z

    After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.

  12. atmospheric rf device: Topics by E-print Network

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

    Tuners with Computationally Efficient Time of Technology, Atlanta, GA 30332 2 Raytheon Company, Tucson AZ, 85734 Abstract -- Modern RF-MEMS device design methods in which...

  13. Active high-power RF switch and pulse compression system

    DOE Patents [OSTI]

    Tantawi, Sami G. (San Mateo, CA); Ruth, Ronald D. (Woodside, CA); Zolotorev, Max (Mountain View, CA)

    1998-01-01T23:59:59.000Z

    A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

  14. Locking Lasers to RF in an Ultra Fast FEL

    E-Print Network [OSTI]

    Wilcox, R.

    2011-01-01T23:59:59.000Z

    Lasers to RF in an Ultrafast FEL R. B . Wilcox, G . Huang,the X-ray pulses from the FEL. The phase-locked loop on the

  15. A new microphonics measurement method for superconducting RF...

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

    new microphonics measurement method for superconducting RF cavities Re-direct Destination: Mechanical vibrations of the superconducting cavity, also known as microphonics, cause...

  16. 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.

  17. Computer control of rf at SLAC

    SciTech Connect (OSTI)

    Schwarz, H.D.

    1985-03-01T23:59:59.000Z

    The Stanford Linear Accelerator is presently upgraded for the SLAC Linear Collider project. The energy is to be increased from approximately 31 GeV to 50 GeV. Two electron beams and one positron beam are to be accelerated with high demands on the quality of the beams. The beam specifications are shown. To meet these specifications, all parameters influencing the beams have to be under tight control and continuous surveillance. This task is accomplished by a new computer system implemented at SLAC which has, among many other functions, control over rf accelerating fields. 13 refs., 8 figs., 2 tabs.

  18. RF Micro Devices | Open Energy Information

    Open Energy Info (EERE)

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I GeothermalPotentialBiopowerSolidGenerationMethodInformationeNevada <REC SolarRFMD Jump to:RF Micro

  19. Sandia National Laboratories: RF & Photonics

    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 PossibleRadiationImplementingnpitche Home AboutMeeting: ProgramFebruaryJunePowerProjectsQuantumRF

  20. Comments on Landau damping due to synchrotron frequency spread

    SciTech Connect (OSTI)

    Ng, K.Y.; /Fermilab

    2005-01-01T23:59:59.000Z

    An inductive/space-charge impedance shifts the synchrotron frequency downwards above/below transition, but it is often said that the coherent synchrotron frequency of the bunch is not shifted in the rigid-dipole mode. On the other hand, the incoherent synchrotron frequency due to the sinusoidal rf always spreads in the downward direction. This spread will therefore not be able to cover the coherent synchrotron frequency, implying that there will not be any Landau damping no matter how large the frequency spread is. By studying the dispersion relation, it is shown that the above argument is incorrect, and there will be Landau damping if there is sufficient frequency spread. The main reason is that the coherent frequency of the rigid-dipole mode will no longer remain unshifted in the presence of a synchrotron frequency spread.

  1. Detection technique and front-end RF tunable filter for cognitive radio systems

    E-Print Network [OSTI]

    Park, Sanghoon

    2010-01-01T23:59:59.000Z

    Introduction to Microelectromechanical Systems Engineer-high reliability. 2. Microelectromechanical system filters [73–80]: Microelectromechanical systems (MEMS) is the

  2. Design of RF/IF analog to digital converters for software radio communication receivers

    E-Print Network [OSTI]

    Thandri, Bharath Kumar

    2007-09-17T23:59:59.000Z

    to analog converter pulses to mitigate problems associated with clock jitter. The architecture also has full control over tuning of the coefficients of the noise transfer function for obtaining the best signal to noise ratio (SNR) performance. The operation...

  3. Automated RF Testing of the KU Agile Radio 2.0 Using LabView

    E-Print Network [OSTI]

    Kansas, University of

    the command line in LabVIEW, writing it to an external command file, and then calling an external ssh client for the transmitter is set by issuing commands to an MC68HC08 microcontroller which in turn sets the control voltage in Figure 1, the micro controller inputs can be seen as blue lines entering the top of the diagram. The 6

  4. Detection technique and front-end RF tunable filter for cognitive radio systems

    E-Print Network [OSTI]

    Park, Sanghoon

    2010-01-01T23:59:59.000Z

    available for personal portable devices [31]. The availableits order allowing personal portable devices to operate onan order al- lowing personal portable devices to operate in

  5. Automatic Pole and Q-Value Extraction for RF Structures

    SciTech Connect (OSTI)

    C. Potratz, H.-W. Glock, U. van Rienen, F. Marhauser

    2011-09-01T23:59:59.000Z

    The experimental characterization of RF structures like accelerating cavities often demands for measuring resonant frequencies of Eigenmodes and corresponding (loaded) Q-values over a wide spectral range. A common procedure to determine the Q-values is the -3dB method, which works well for isolated poles, but may not be applicable directly in case of multiple poles residing in close proximity (e.g. for adjacent transverse modes differing by polarization). Although alternative methods may be used in such cases, this often comes at the expense of inherent systematic errors. We have developed an automation algorithm, which not only speeds up the measurement time significantly, but is also able to extract Eigenfrequencies and Q-values both for well isolated and overlapping poles. At the same time the measurement accuracy may be improved as a major benefit. To utilize this procedure merely complex scattering parameters have to be recorded for the spectral range of interest. In this paper we present the proposed algorithm applied to experimental data recorded for superconducting higher-order-mode damped multi-cell cavities as an application of high importance.

  6. Operation of the superconducting RF photo gun at ELBE

    E-Print Network [OSTI]

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, Ch; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2012-01-01T23:59:59.000Z

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 ?A average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  7. Operation of the superconducting RF photo gun at ELBE

    E-Print Network [OSTI]

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2011-01-01T23:59:59.000Z

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 µA average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  8. Improved manufacturing techniques for RF and laser hardening of missile domes. Phase I. Technical report

    SciTech Connect (OSTI)

    Pawlewicz, W.T.; Mann, I.B.; Martin, P.M.; Hays, D.D.; Graybeal, A.G.

    1982-07-01T23:59:59.000Z

    This report summarizes key results and accomplishements during the first year of a Manufacturing Methods and Technology project to adapt an existing Pacific Northwest Laboratory (PNL) optical coating capability developed for high-power fusion-laser applications to the case of rf and laser hardening of plastic missile domes used by the US Army (MICOM). The primary objective of the first year's work was to demonstrate rf hardening of Hellfire and Copperhead 1.06-micron missile domes by use of transparent conductive Indium Tin Oxide (ITO) coatings. The project thus involved adaptation of a coating material and process developed for flat glass components used in fusion lasers to the case of hemispherical or conical heat-sensitive plastic domes used on laser-guided missiles. Specific ITO coating property goals were an electrical sheet resistance of 10 Ohms/square, a coated-dome transmission of 80% or more at 1.06 micron wavelength (compared to 90% for a bare dome), and good adhesion. The sheet resistance goal of 10 Ohms/square was expected to result in an rf attenuation of 30 dB at the frequencies of importance.

  9. 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 ...

  10. Comparative studies of artificial intelligence techniques in the context of cognitive radio

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -utilization of valuable frequency resources. To address this critical problem, Federal Communications Commission (FCC) has communication system that is aware of its environment, can also learn from experience and can make changes to the incoming RF stimuli in real- time. The main objective of a CR is to have a highly reliable communications

  11. RF Power Degradation of GaN High Electron Mobility Transistors

    E-Print Network [OSTI]

    Joh, Jungwoo

    We have developed a versatile methodology to systematically investigate the RF reliability of GaN High-Electron Mobility Transistors. Our technique utilizes RF and DC figures of merit to diagnose the degradation of RF ...

  12. 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.

  13. 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...

  14. Cooling at the quantum limit and RF refrigeration

    E-Print Network [OSTI]

    Fominov, Yakov

    Cooling at the quantum limit and RF refrigeration Jukka Pekola Low Temperature Laboratory, Helsinki) Francesco Giazotto (SNS Pisa) Yuri Pashkin (NEC) #12;Outline Electronic refrigeration Classical vs quantum (electromagnetic) heat transport Cooling at the quantum limit: experiments RF refrigeration in a single

  15. RF-MEMS capacitive switches with high reliability

    DOE Patents [OSTI]

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03T23:59:59.000Z

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  16. 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.

  17. Bandwidth utilization maximization of scientific RF communication systems

    SciTech Connect (OSTI)

    Rey, D. [Sandia National Lab., Albuquerque, NM (United States); Ryan, W. [New Mexico State Univ., Las Cruces, NM (United States); Ross, M.

    1997-01-01T23:59:59.000Z

    A method for more efficiently utilizing the frequency bandwidth allocated for data transmission is presented. Current space and range communication systems use modulation and coding schemes that transmit 0.5 to 1.0 bits per second per Hertz of radio frequency bandwidth. The goal in this LDRD project is to increase the bandwidth utilization by employing advanced digital communications techniques. This is done with little or no increase in the transmit power which is usually very limited on airborne systems. Teaming with New Mexico State University, an implementation of trellis coded modulation (TCM), a coding and modulation scheme pioneered by Ungerboeck, was developed for this application and simulated on a computer. TCM provides a means for reliably transmitting data while simultaneously increasing bandwidth efficiency. The penalty is increased receiver complexity. In particular, the trellis decoder requires high-speed, application-specific digital signal processing (DSP) chips. A system solution based on the QualComm Viterbi decoder and the Graychip DSP receiver chips is presented.

  18. Void formation and dust cloud structure in (a)symmetric RF discharges

    SciTech Connect (OSTI)

    Goedheer, W.J.; Akdim, M.R.; Land, V. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2005-10-31T23:59:59.000Z

    The behaviour of dust particles in a discharge is the result of the concerted action of the charging process and forces like gravity, the ion and neutral drag force, and the thermophoretic force. Since the ion drag force plays a major role, the reactor geometry and the ion density profile are important parameters. In this paper we study the influence of the geometrical features of a radio-frequency discharge, such as asymmetry, ring electrodes, and a depression in the electrodes.

  19. Semianalytic model of electron pulse propagation: Magnetic lenses and rf pulse compression cavities

    SciTech Connect (OSTI)

    Berger, Joel A.; Schroeder, W. Andreas [Department of Physics, University of Illinois at Chicago, 845 W. Taylor (M/C 273), Chicago, Illinois 60607 (United States)

    2010-12-15T23:59:59.000Z

    The analytical Gaussian electron pulse propagation model of Michalik and Sipe [J. Appl. Phys. 99, 054908 (2006)] is extended to include the action of external forces on the pulse. The resultant ability to simulate efficiently the effect of electron optical elements (e.g., magnetic lenses and radio-frequency cavities) allows for the rapid assessment of electron pulse delivery systems in time-resolved ultrafast electron diffraction and microscopy experiments.

  20. Hydrogen-filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    CHARLES, Ankenbrandt

    2009-04-17T23:59:59.000Z

    Ionization cooling requires low-Z energy absorbers immersed in a strong magnetic field and high-gradient, large-aperture RF cavities to be able to cool a muon beam as quickly as the short muon lifetime requires. RF cavities that operate in vacuum are vulnerable to dark-current- generated breakdown, which is exacerbated by strong magnetic fields, and they require extra safety windows that degrade cooling, to separate RF regions from hydrogen energy absorbers. RF cavities pressurized with dense hydrogen gas will be developed that use the same gas volume to provide the energy absorber and the RF acceleration needed for ionization cooling. The breakdown suppression by the dense gas will allow the cavities to operate in strong magnetic fields. Measurements of the operation of such a cavity will be made as functions of external magnetic field and charged particle beam intensity and compared with models to understand the characteristics of this technology and to develop mitigating strategies if necessary.