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Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

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

Scientists at Argonne National Laboratory have created innovations in the design and fabrication of radio frequency (RF) cavities that improve ...

2

Radio-Frequency (RF) Devices for Safeguards: Where We Are and Where We Need to Go  

Science Conference Proceedings (OSTI)

Radio-Frequency (RF) devices have revolutionized many aspects of modern industrial processes. RF technology can enable wireless communication for tag identification, sensor communication, and asset tracking. Radio-frequency identification (RFID) is a technology that utilizes wireless communication to interrogate and identify an electronic tag attached to an item in order to identify the item. The technology can come in many forms: passive or active tags, low to ultra-wideband frequencies, small paper-thin tags to brick-sized units, and simple tags or highly integrated sensor packages. RF technology, and specifically RFID, has been applied widely in commercial markets for inventory, supply chain management, and asset tracking. Several recent studies have demonstrated the safeguards benefits of utilizing RFID versus conventional inventory tagging methods for tracking nuclear material. These studies have indicated that the RF requirements for safeguards functions are more stringent than the RF requirements for other inventory tracking and accounting applications. Additionally, other requirements must be addressed, including environmental and operating conditions, authentication, and tag location and attachment. Facility restrictions on radio spectrum, method of tag attachment, and sensitivity of the data collected impact the tag selection and system design. More important, the intended use of the system must be considered. The requirements for using RF to simply replace or supplement container identifiers such as bar codes that facilitate the inventory function will differ greatly from the requirements for deploying RF for unattended monitoring applications. Several studies have investigated these considerations to advance commercial RF devices for safeguards use, and a number of system concepts have been developed. This paper will provide an overview of past studies and current technologies, and will investigate the requirements, existing gaps, and several potential next steps for advancing RF techniques for safeguards use.

Rowe, Nathan C [ORNL; Younkin, James R [ORNL; Pickett, Chris A [ORNL; Whitaker, J Michael [ORNL

2011-01-01T23:59:59.000Z

3

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks  

Science Conference Proceedings (OSTI)

In this paper the per-node throughput and end-to-end delay of randomly deployed (i.e. ad-hoc) hybrid radio frequency - free space optics (RF/FSO) networks are studied. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, f(n) ... Keywords: Ad hoc networks, Delay, Free space optics, Hybrid networks, Throughput capacity

Di Wang; Alhussein A. Abouzeid

2011-05-01T23:59:59.000Z

4

Radio frequency coaxial feedthrough device  

DOE Patents (OSTI)

A radio frequency coaxial vacuum feedthrough is provided which utilizes a cylindrical ceramic vacuum break formed of an alumina ceramic. The cylinder is coaxially disposed and brazed between tapered coaxial conductors to form a vacuum sealed connection between a pressurized upstream coaxial transmission line and a utilization device located within a vacuum container. The feedthrough provides 50 ohm matched impedance RF feedthrough up to about 500 MHz at power levels in the multimegawatt range.

Owens, Thomas L. (Kingston, TN); Baity, Frederick W. (Oak Ridge, TN); Hoffman, Daniel J. (Oak Ridge, TN); Whealton, John H. (Oak Ridge, TN)

1987-01-01T23:59:59.000Z

5

Home monitoring using wearable radio frequency transmitters  

Science Conference Proceedings (OSTI)

Background: Location tracking of a wearable radio frequency (RF) transmitter in a wireless network is a potentially useful tool for the home monitoring of patients in clinical applications. However, the problem of converting RF signals into accurate ... Keywords: Gaussian mixture models, Home monitoring, Motion tracking, Wireless network

Anthony Almudevar; Adrian Leibovici; Aleksey Tentler

2008-02-01T23:59:59.000Z

6

A Power-efficient Radio Frequency Energy-harvesting Circuit .  

E-Print Network (OSTI)

??This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection.… (more)

Khoury, Philip

2013-01-01T23:59:59.000Z

7

Stabilized radio frequency quadrupole  

DOE Patents (OSTI)

Disclosed is 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. 5 figs.

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

1984-12-25T23:59:59.000Z

8

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

DOE Patents (OSTI)

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.

Norem, James H.; Pellin, Michael J.

2013-06-11T23:59:59.000Z

9

Radio frequency fingerprinting commercial communication devices to enhance electronic security  

Science Conference Proceedings (OSTI)

There is a current shift toward protecting against unauthorised network access at the open systems interconnection physical layer by exploiting radio frequency characteristics that are difficult to mimic. This work addresses the use of RF 'fingerprints' ... Keywords: Fisher linear discriminant, OSI, PHY layer authentication, RF fingerprinting, RF forensics, SEI, access authorisation, anti-spoofing, burst detection, commercial communication devices, electronic security, feature generation, multiple discriminant analysis, network access, physical layer authentication, radio frequency fingerprinting, signal features, specific emitter identification, transient detection

William C. Suski II; Michael A. Temple; Michael J. Mendenhall; Robert F. Mills

2008-10-01T23:59:59.000Z

10

Towards Optimization of Probe Placement for Radio-Frequency Ablation  

E-Print Network (OSTI)

's electric potential and of the steady state of the heat distribution during RF ablation. The optimization of the optimization to artificial data and a comparison to a real RF ablation are presented. 1 Introduction on Cartesian or tetrahedral grids. In this work we consider the radio-frequency (RF) ablation of liver tumors

Preusser, Tobias

11

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

NLE Websites -- All DOE Office Websites (Extended Search)

Home Teams Low-Level Radio Frequency Magnet Power Supplies, Pulsed Power Radio Frequency, High Voltage Technologies Radio Frequency Operations CONTACTS Group Leader Dan Rees Deputy...

12

Radio frequency sustained ion energy  

SciTech Connect

Electromagnetic (E.M.) energy injection method and apparatus for producing and sustaining suprathermal ordered ions in a neutral, two-ion-species, toroidal, bulk equilibrium plasma. More particularly, the ions are produced and sustained in an ordered suprathermal state of existence above the average energy and velocity of the bulk equilibrium plasma by resonant rf energy injection in resonance with the natural frequency of one of the ion species. In one embodiment, the electromagnetic energy is injected to clamp the energy and velocity of one of the ion species so that the ion energy is increased, sustained, prolonged and continued in a suprathermal ordered state of existence containing appreciable stored energy that counteracts the slowing down effects of the bulk equilibrium plasma drag. Thus, selective deuteron absorption may be used for ion-tail creation by radio-frequency excitation alone. Also, the rf can be used to increase the fusion output of a two-component neutral injected plasma by selective heating of the injected deuterons.

Jassby, Daniel L. (Princeton, NJ); Hooke, William M. (Princeton, NJ)

1977-01-01T23:59:59.000Z

13

Development of Radio Frequency Exposure Standards  

Science Conference Proceedings (OSTI)

While unconfirmed claims of adverse human health effects from electromagnetic radiation date to the 1930s, development of modern safety standards did not begin until the 1952 Hirsch study of eye damage at a microwave power density of 100 mW/cm2. Early work on standards focused on microwave frequencies due to rapid development of radar and microwave communications links. In the years since 1952, radio frequency (RF) exposure standards have kept pace with those technological advancements. While refinements...

2004-11-01T23:59:59.000Z

14

Overview of Personal Radio Frequency Communication Technologies  

Science Conference Proceedings (OSTI)

The growth of wireless electronic communication devices and their applications is creating an increasingly complex radio frequency (RF) environment in the workplace and home. Personal communication applications discussed in this report include cordless telephones, analog cellular telephones, digital cellular telephones, and a dozen more. Depending on the specific wireless device, different frequency ranges, modulation types, multiple access types, and power levels can be encountered. The significant grow...

2008-09-09T23:59:59.000Z

15

Radio frequency coaxial feedthrough  

DOE Patents (OSTI)

An improved radio frequency coaxial transmission line vacuum feed-through provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflections from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits voltage and power handling capabilities of a feedthrough.

Owens, Thomas L. (Kingston, TN)

1989-01-17T23:59:59.000Z

16

Stabilized radio-frequency quadrupole  

DOE Patents (OSTI)

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.

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

1982-09-29T23:59:59.000Z

17

Radio Frequency Identification Tags - Active Tags ...  

Selectable, license free, RF frequency bands; Ultra low power sleep mode; Miniaturized, encapsulated bendable packaging;

18

Design and characterization of a radio-frequency dc/dc power converter  

E-Print Network (OSTI)

The use of radio-frequency (RF) amplifier topologies in dc/dc power converters allows the operating frequency to be increased by more than two orders of magnitude over the frequency of conventional converters. This enables ...

Jackson, David A. (David Alexander)

2005-01-01T23:59:59.000Z

19

Software-Defined Ultra-wideband Radio Communications: A New RF Technology for Emergency Response Applications  

SciTech Connect

Reliable wireless communication links for local-area (short-range) and regional (long-range) reach capabilities are crucial for emergency response to disasters. Lack of a dependable communication system can result in disruptions in the situational awareness between the local responders in the field and the emergency command and control centers. To date, all wireless communications systems such as cell phones and walkie-talkies use narrowband radio frequency (RF) signaling for data communication. However, the hostile radio propagation environment caused by collapsed structures and rubble in various disaster sites results in significant degradation and attenuation of narrowband RF signals, which ends up in frequent communication breakdowns. To address the challenges of reliable radio communication in disaster fields, we propose an approach to use ultra-wideband (UWB) or wideband RF waveforms for implementation on Software Defined Radio (SDR) platforms. Ultra-wideband communications has been proven by many research groups to be effective in addressing many of the limitations faced by conventional narrowband radio technologies. In addition, LLNL's radio and wireless team have shown significant success in field deployment of various UWB communications system for harsh environments based on LLNL's patented UWB modulation and equalization techniques. Furthermore, using software defined radio platform for UWB communications offers a great deal of flexibility in operational parameters and helps the radio system to dynamically adapt itself to its environment for optimal performance.

Nekoogar, F; Dowla, F

2009-10-19T23:59:59.000Z

20

Extremely high frequency RF effects on electronics.  

SciTech Connect

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.

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

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

A radio frequency coaxial feedthrough  

DOE Patents (OSTI)

An improved radio frequency coaxial transmission line vacuum feedthrough is provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflection from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits the voltage and power handling capabilities of a feedthrough.

Owens, T.L.

1987-12-07T23:59:59.000Z

22

Integrally formed radio frequency quadrupole  

DOE Patents (OSTI)

An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.

Abbott, Steven R. (Concord, CA)

1989-01-01T23:59:59.000Z

23

High power radio frequency attenuation device  

DOE Patents (OSTI)

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.

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

1984-01-01T23:59:59.000Z

24

Security approaches for Radio Frequency Identification systems  

E-Print Network (OSTI)

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 ...

Foley, Joseph Timothy, 1976-

2007-01-01T23:59:59.000Z

25

Radio Frequency Identification : regulating information privacy protection  

E-Print Network (OSTI)

As applications of Radio Frequency Identification (RFID) become more profuse, the technology itself is stirring up some controversy. Due to its potential for amassing large amounts of information about both people and ...

Laufer, Deanna (Deanna Raquel)

2007-01-01T23:59:59.000Z

26

Energy Saving Glass Lamination via Selective Radio-Frequency Heating  

SciTech Connect

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.

Shulman, Holly S.; Allan, Shawn M.

2009-11-11T23:59:59.000Z

27

Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators  

Science Conference Proceedings (OSTI)

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.

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

2011-03-01T23:59:59.000Z

28

Method of making radio frequency ion source antenna  

DOE Patents (OSTI)

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.

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

1988-01-01T23:59:59.000Z

29

Characterization of Radio Frequency Emissions From Two Models of Wireless Smart Meters  

Science Conference Proceedings (OSTI)

Concomitant with the widespread deployment of Advanced Metering Infrastructure (AMI) is the need to characterize radio-frequency (RF) emissions from wireless smart meters. A previous EPRI Technical Report (1021126) provided a detailed characterization of RF emissions from one type of wireless smart meter deployed across several service territories in the U.S. This report describes emissions from wireless smart meters produced by two manufacturers that are currently in operation within a large service ter...

2011-12-08T23:59:59.000Z

30

Collisionless electron heating by radio frequency bias in low gas pressure inductive discharge  

SciTech Connect

We show experimental observations of collisionless electron heating by the combinations of the capacitive radio frequency (RF) bias power and the inductive power in low argon gas pressure RF biased inductively coupled plasma (ICP). With small RF bias powers in the ICP, the electron energy distribution (EED) evolved from bi-Maxwellian distribution to Maxwellian distribution by enhanced plasma bulk heating and the collisionless sheath heating was weak. In the capacitive RF bias dominant regime, however, high energy electrons by the RF bias were heated on the EEDs in the presence of the ICP. The collisionless heating mechanism of the high energy electrons transited from collisionless inductive heating to capacitive coupled collisionless heating by the electron bounce resonance in the RF biased ICP.

Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

2012-12-10T23:59:59.000Z

31

Program on Technology Innovation: Frequently Asked Questions (FAQ) on Radio-Frequency Electromagnetic Fields  

Science Conference Proceedings (OSTI)

The number of sources of radio-frequency (RF) electromagnetic fields in our midst has increased dramatically in the past three decades. From cordless phones, to cellular phones and their base stations, to pagers and walkie-talkies, to WiFi in public venues, such as coffee shops and airports, and to smart meters and other wireless components of the smart grid. Of course, since the advent of broadcast radio and TV during the 20th century, radio-frequency electromagnetic fields have been an ...

2012-11-05T23:59:59.000Z

32

High Frequency High Power RF Generation using a Relativistic...  

NLE Websites -- All DOE Office Websites (Extended Search)

FREQUENCY HIGH POWER RF GENERATION USING A RELATIVISTIC ELECTRON BEAM C. Jing , S. Antipov, P. Schoessow, and A. Kanareykin, Euclid Techlabs LLC, Solon, OH-44139 J.G. Power, M....

33

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

SciTech Connect

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

Allan, Shawn M.

2012-02-27T23:59:59.000Z

34

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

SciTech Connect

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

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

2012-02-27T23:59:59.000Z

35

Development of Equipment to Separate Nonthermal and Thermal Effects of Radio Frequency Energy on Microorganisms  

SciTech Connect

A radio frequency (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.

D.J. Geveke; M. Kozempel; C. Brunkhorst

1999-11-01T23:59:59.000Z

36

Radio Frequency Noise Effects on the CERN Large Hadron Collider Beam Diffusion  

SciTech Connect

Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.

Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; /CERN; Rivetta, C.; Fox, J.D.; /SLAC

2012-04-30T23:59:59.000Z

37

Economics of shale oil production by radio frequency heating  

DOE Green Energy (OSTI)

A conceptual facility for the production of shale oil by radio frequency(rf) heating has been designed to evaluate the economic feasibility of this technique. In the proposed procedure, the shale is processed in situ without being rubbed or explosively fractured. Metal electrodes inserted in a set of vertical drill holes are energized by a group of rf oscillators. The holes bound a block of shale that is to be retorted. The electric field is developed in such a way that heating within the block is almost uniform, and heating outside the block is very low. Retorting of the shale results in a pressure buildup of the hydrocarbon fluids. The oil and gas move horizontally (parallel to bedding planes), then down the electrode holes to a collection manifold. The facility schedule is planned so that off-peak electric power from existing generating stations can be used to operate the oscillators. Thus, the cost of power and the capital requirements for the facility are held to a minimum. Oil production costs and capital requirements indicate that the proposed procedure is economically attractive. The two principal costs are purchase of electric power and mining operations. The largest capital requirement is oscillators and associated electrical equipment.

Mallon, R.G.

1980-05-07T23:59:59.000Z

38

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

DOE Green Energy (OSTI)

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.

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

2009-11-11T23:59:59.000Z

39

H- radio frequency source development at the Spallation Neutron Source  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Welton, Robert F [ORNL; Pennisi, Terry R [ORNL; Roseberry, Ron T [ORNL; Stockli, Martin P [ORNL

2012-01-01T23:59:59.000Z

40

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

SciTech Connect

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.

Dowla, F

2007-03-14T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

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

SciTech Connect

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.

Dowla, F

2007-03-14T23:59:59.000Z

42

Macroscopic Diversity in Frequency Reuse Radio Systems  

Science Conference Proceedings (OSTI)

Macroscopic diversity is a technique that can facilitate high quality and ubiquitous communications between low-power portable radiotelephones and data terminals, and radio base stations (ports) that are connected to the local network. It uses radio ...

R. Bernhardt

2006-09-01T23:59:59.000Z

43

Radio Frequency Identification Tags - Semi Passive (Battery ...  

PNNL developed this semi-passive RF Tag for the Army to detect and locate nightvision goggles in a cluttered ... and boxes it is easier to track and ...

44

Radio Frequency Lamination for Photovoltaic Panels  

Science Conference Proceedings (OSTI)

Strategies for overcoming residual stress in interlayers surrounding embedded PV cells will be discussed. Working prototypes of RF laminated solar panels will ...

45

Trirotron: triode rotating beam radio frequency amplifier  

DOE Patents (OSTI)

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.

Lebacqz, Jean V. (Stanford, CA)

1980-01-01T23:59:59.000Z

46

Chips, tags and scanners: Ethical challenges for radio frequency identification  

Science Conference Proceedings (OSTI)

Radio Frequency Identification (RFID) systems identify and track objects, animals and, in principle, people. The ability to gather information obtained by tracking consumer goods, government documents, monetary transactions and human beings raises a ... Keywords: RFID, business ethics, ethics, privacy, radio frequency identification, surveillance

Dara J. Glasser; Kenneth W. Goodman; Norman G. Einspruch

2007-07-01T23:59:59.000Z

47

Method and apparatus for radio frequency ceramic sintering  

DOE Patents (OSTI)

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.

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

1993-11-30T23:59:59.000Z

48

Method and apparatus for radio frequency ceramic sintering  

DOE Patents (OSTI)

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.

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

1993-01-01T23:59:59.000Z

49

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

DOE Patents (OSTI)

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.

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

1994-01-01T23:59:59.000Z

50

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

DOE Patents (OSTI)

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.

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

1994-03-08T23:59:59.000Z

51

High-power radio-frequency attenuation device  

DOE Patents (OSTI)

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.

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

1981-12-30T23:59:59.000Z

52

RFIDSim : a discrete event simulator for Radio Frequency Identification systems  

E-Print Network (OSTI)

This thesis presents RFIDSim, a discrete event process-oriented simulator designed to model Radio Frequency Identification (RFID) communication. The simulator focuses on the discovery and identification process of passive ...

Yu, Kenneth Kwan-Wai, 1979-

2003-01-01T23:59:59.000Z

53

Radio-frequency spectroscopy of ultracold atomic Fermi gases  

E-Print Network (OSTI)

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 ...

Schirotzek, Andre

2010-01-01T23:59:59.000Z

54

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

SciTech Connect

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.

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

55

Multi-dimensional ultra-high frequency passive radio frequency identification tag antenna designs  

E-Print Network (OSTI)

In this thesis, we present the design, simulation, and empirical evaluation of two novel multi-dimensional ultra-high frequency (UHF) passive radio frequency identification (RFID) tag antennas, the Albano-Dipole antenna ...

Delichatsios, Stefanie Alkistis

2006-01-01T23:59:59.000Z

56

Collaborative spectrum sensing in cognitive radio networks.  

E-Print Network (OSTI)

??The radio frequency (RF) spectrum is a scarce natural resource, currently regulated by government agencies. With the explosive emergence of wireless applications, the demands for… (more)

Sun, Hongjian

2011-01-01T23:59:59.000Z

57

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

SciTech Connect

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

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

2010-12-07T23:59:59.000Z

58

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network (OSTI)

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Kevin Green; Jonathan L. Rosner; Denis A. Suprun; J. F. Wilkerson

2002-05-03T23:59:59.000Z

59

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

DOE Green Energy (OSTI)

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.

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

1991-01-01T23:59:59.000Z

60

Electromagnetic and mechanical design of gridded radio-frequency cavity windows  

SciTech Connect

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.

Alsharoa, Mohammad M.; /IIT, Chicago /Fermilab

2004-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Dielectric supported radio-frequency cavities  

DOE Patents (OSTI)

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.

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

2000-01-01T23:59:59.000Z

62

Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency  

NLE Websites -- All DOE Office Websites (Extended Search)

Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Heating" Inventors..--.. Christopher D. Brunkhorst, David J. Geveke, Andrew B. W. Bigley. This disclosure is directed to a system for pasteurizing shell eggs. The system includes an egg rotating assembly structured to rotate the egg, and electrodes that are in contact with the egg. The system is structured so that, as the rotating assembly rotates the egg, radio frequency energy is directed to the egg to pasteurize it. Nearly 200 million "shell eggs" are consumed in the United States (US) each day. "Shell eggs" are non-powdered conventional eggs that are naturally produced by hens. Shell eggs are among the most nutritious foods on earth and can be part of a healthy diet. However, some unbroken, clean, fresh

63

Test results of the AGS Booster low frequency RF system  

Science Conference Proceedings (OSTI)

The Band II RF system was originally built to support the Booster operations during the acceleration of heavy ions. Designed to sweep from 0.6 to 2.5 MHz, it was build and successfully tested over a much broader range reaching 4 MHz. Voltages up to more than 20 kV were reached over the design frequency range. The system consists of two stations, each of which is made of one single gap cavity directly driven by a grounded cathode push pull power amplifier. The low Q high permeability ferrites needed in the coaxial cavity in order to reach the lower end of the band make tuning extremely easy. Both systems were thoroughly tested both at single frequencies and on a sweep and are now installed in the ring, ready for operations. Static measurements showed no high-loss effects. The Band 11 system has been fully described in a previous paper; presented here are the results of the ``bench`` tests that lead to important performance improvements.

Sanders, R.T.; Cameron, P.; Damm, R.; Dunbar, A.; Goldman, M.; Kasha, D.; McNerney, A.; Meth, M.; Ratti, A.; Spitz, R.

1993-06-01T23:59:59.000Z

64

Radio frequency dc-dc power conversion  

E-Print Network (OSTI)

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 ...

Rivas, Juan, 1976-

2007-01-01T23:59:59.000Z

65

Plasma ignition schemes for the SNS radio-frequency driven H- source  

E-Print Network (OSTI)

on the Spallation Neutron Source (SNS) Project,” EPAC ‘98,ignition schemes for the SNS radio-frequency driven H -the Spallation Neutron Source (SNS) is a cesiated, radio-

2001-01-01T23:59:59.000Z

66

Method of making radio frequency ion source antenna and such antenna  

DOE Patents (OSTI)

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.

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

1985-05-22T23:59:59.000Z

67

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

E-Print Network (OSTI)

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.

Siverns, J D; Weidt, S; Hensinger, W K

2011-01-01T23:59:59.000Z

68

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

E-Print Network (OSTI)

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.

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

2011-06-24T23:59:59.000Z

69

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

E-Print Network (OSTI)

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.

Amur Margaryan

2009-10-16T23:59:59.000Z

70

Radio-Frequency Identification (RFID) applications: A brief introduction  

Science Conference Proceedings (OSTI)

This short paper introduces the key concepts behind RFID technology and presents a brief historical perspective. Examples of RFID applications are also given to highlight the developing popularity of the technology in many sectors. This paper will provide ... Keywords: Antenna, Radio-Frequency Identification, Reader, Tagging, Tracking, Transponder

Konstantinos Domdouzis; Bimal Kumar; Chimay Anumba

2007-10-01T23:59:59.000Z

71

Low-power/low-voltage RF microsystems for wireless sensors networks  

Science Conference Proceedings (OSTI)

This paper presents radio-frequency (RF) microsystems (MSTs) composed by low-power devices for use in wireless sensors networks (WSNs). The RF CMOS transceiver is the main electronic system and its power consumption is a critical issue. Two RF CMOS transceivers ... Keywords: RF CMOS transceiver, RF microsystems, Wireless sensors networks

J. P. Carmo; J. H. Correia

2009-12-01T23:59:59.000Z

72

Radio frequency pulse compression experiments at SLAC (Stanford Linear Accelerator Center)  

Science Conference Proceedings (OSTI)

Proposed future positron-electron linear colliders would be capable of investigating fundamental processes of interest in the 0.5--5 TeV beam-energy range. At the SLAC Linear Collider (SLC) gradient of about 20 MV/m this would imply prohibitive lengths of about 50--250 kilometers per linac. We can reduce the length by increasing the gradient but this implies high peak power, on the order of 400-- to 1000-MW at X-Band. One possible way to generate high peak power is to generate a relatively long pulse at a relatively low power and compress it into a short pulse with higher peak power. It is possible to compress before DC to RF conversion, as is done using magnetic switching for induction linacs, or after DC to RF conversion, as is done for the SLC. Using RF pulse compression it is possible to boost the 50-- to 100-MW output that has already been obtained from high-power X-Band klystrons the levels required by the linear colliders. In this note only radio frequency pulse compression (RFPC) is considered.

Farkas, Z.D.; Lavine, T.L.; Menegat, A.; Miller, R.H.; Nantista, C.; Spalek, G.; Wilson, P.B.

1991-01-01T23:59:59.000Z

73

Radio frequency communication system utilizing radiating transmission lines  

DOE Patents (OSTI)

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.

Struven, Warren C. (San Carlos, CA)

1984-01-01T23:59:59.000Z

74

Electronic Radio-Frequency (Electrodeless) Induction Lamps: A Fluorescent Technology  

Science Conference Proceedings (OSTI)

This EPRI Technical Update addresses an expanding energy efficient light source electronic radio-frequency (electrodeless) induction lamps. Business and technical market factors (Chapter 2) use the past and future growth of the CFL market to illustrate the potential for the induction lighting market while emphasizing future technical improvements. Discussion of the importance of utility involvement in helping their customers consider induction lamps for high-efficiency fluorescent applications with long-...

2007-12-20T23:59:59.000Z

75

Field Emission Cathode Gating for RF Electron Guns (IN-04-039)  

Scientists at Argonne National Laboratory have created an innovative way to enhance the performance of radio frequency (RF) electron guns: a method of ...

76

Current Challenges and Physics of Superconducting Radio-Frequency...  

NLE Websites -- All DOE Office Websites (Extended Search)

Recent performance advances in superconducting RF (SRF) cavities have made RF superconductivity a vital technology for accelerators which serve a variety of experimental...

77

Radio-frequency measurements of UNiX compounds (X= Al, Ga, Ge) in high magnetic fields  

SciTech Connect

We performed radio-frequency (RF) skin-depth measurements of antiferromagnetic UNiX compounds (X=Al, Ga, Ge) in magnetic fields up to 60 T and at temperatures between 1.4 to {approx}60 K. Magnetic fields are applied along different crystallographic directions and RF penetration-depth was measured using a tunnel-diode oscillator (TDO) circuit. The sample is coupled to the inductive element of a TDO resonant tank circuit, and the shift in the resonant frequency {Delta}f of the circuit is measured. The UNiX compounds exhibit field-induced magnetic transitions at low temperatures, and those transitions are accompanied by a drastic change in {Delta}f. The results of our skin-depth measurements were compared with previously published B-T phase diagrams for these three compounds.

Mielke, Charles H [Los Alamos National Laboratory; Mcdonald, David R [Los Alamos National Laboratory; Zapf, Vivien [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Lacerda, Alex H [Los Alamos National Laboratory; Adak, Sourav [Los Alamos National Laboratory; Karunakar, Kothapalli [Los Alamos National Laboratory; Nakotte, Heinrich [Los Alamos National Laboratory; Chang, S [NIST; Alsmadi, A M [HASHEMITE UNIV; Alyones, S [HASHEMIT UNIV

2009-01-01T23:59:59.000Z

78

Low-Level Radio Frequency System Development for the National Synchrotron Light Source II  

SciTech Connect

The National Synchrotron Light Source-II (NSLS-II) is a new ultra-bright 3GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. The position and timing specifications of the ultra-bright photon beam imposes a set of stringent requirements on the performance of radio frequency (RF) control. In addition, commissioning and staged installation of damping wigglers and insertion devices requires the flexibility of handling varying beam conditions. To meet these requirements, a digital implementation of the LLRF is chosen, and digital serial links are planned for the system integration. The first prototype of the controller front-end hardware has been built, and is currently being tested.

Ma,H.; Rose, J.

2009-05-04T23:59:59.000Z

79

Ross Ice Shelf in situ radio-frequency ice attenuation  

E-Print Network (OSTI)

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.

Taylor Barrella; Steven Barwick; David Saltzberg

2010-11-02T23:59:59.000Z

80

rf  

NLE Websites -- All DOE Office Websites (Extended Search)

RF RF It's what makes the protons go 'round. The latest in a series explaining particle physics in everyday language. Painless Physics Articles BEAM COOLING August 2, 1996 By Leila Belkora, Office of Public Affairs ACCELERATION August 16, 1996 By Dave Finley, Accelerator Division Head RF August 30, 1996 By Pat Colestock, Accelerator Division FIXED TARGET PHYSICS September 20, 1996 By Peter H. Garbincius, Physics Section FIXED TARGET PHYSICS PART DEUX October 16, 1996 By Peter H. Garbincius, Physics Section and Leila Belkora, Office of Public Affaris CROSS SECTION November 1, 1996 By Doreen Wackeroth, Theoretical Physics Edited by Leila Belkora, Office of Public Affaris MAGNETS PART I November 15, 1996 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Characterization of nonthermal Ne-N{sub 2} mixture radio frequency discharge  

Science Conference Proceedings (OSTI)

This paper deals with optical emission spectroscopic studies of low pressure (p=0.1{yields}0.5 mbar) Ne-N{sub 2} capacitively coupled radio frequency (rf) plasma that can be used for plasma nitriding, etc. It reports the methods to calculate the electron temperature (T{sub e}) in nonthermal plasmas. Since, the selected Ne I lines, used to calculate electron temperature, are found in corona balance; therefore, it allows us to use modified Boltzmann technique to calculate electron temperature. Langmuir probe is also used to calculate electron temperature and electron energy distribution functions (EEDFs). The measurements are worked out for different discharge parameters like neon percentage, filling pressure and RF power. It is found that electron temperature increases with the increase in neon percentage and decreases with the increase in pressure, whereas excitation temperature (T{sub exc}) increases with power, neon percentage, and decreases with pressure. It is also observed that electron temperature measured by Langmuir probe technique is slightly greater than the one measured via modified Boltzmann plot method. The tails of the EEDFs gain height and extend toward the higher energy with the increase in neon percentage in the mixture.

Rehman, N. U.; Zakaullah, M. [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Khan, F. U. [Department of Physics, Gomal University, 29050 D.I. Khan (Pakistan); Naseer, S. [Department of Physics, Peshawar University, 25120 Peshawar (Pakistan)

2008-12-15T23:59:59.000Z

82

H{sup -} radio frequency source development at the Spallation Neutron Source  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)

2012-02-15T23:59:59.000Z

83

Radio-Frequency Interference (RFI) From Extra-High- Voltage (EHV) Transmission Lines  

E-Print Network (OSTI)

The subject of radio-frequency interference (RFI) generated by high-voltage transmission lines has long been of both academic and commercial interest because of concerns about

Patrick C. Crane

2010-01-01T23:59:59.000Z

84

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

For years, radio frequency identification (RFID) technology has been used in a variety of applications, from passports to inventory tracking in retail ...

85

RFQ (radio-frequency quadrupole) acceleration section and its optimization  

SciTech Connect

The acceleration section is a crucial component of any radio- frequency quadrupole (RFQ). It is common a practice to design this section with a constant modulation factor equal to its value at the end of the gentle buncher. A new method of design is proposed in this paper. The algorithm is based on the fact that the transverse space-charge current limit (TCL) is approximately proportional to the instantaneous velocity of the accelerated particle and the longitudinal space-charge current limit (LCL) is nearly independent of the velocity in the acceleration section. The modulation factor is increased such that the TCL is slightly larger than the double of the design current. Simulation using this method shows that transmission efficiency and emittances are the same as the conventional design. The advantage gained is a 50-75% increase in accelerating rate. The optimization of the length of this section is also discussed. 3 refs., 4 figs., 1 tab.

Raparia, D.

1988-01-01T23:59:59.000Z

86

Superconducting radio-frequency modules test faciilty operating experience  

Science Conference Proceedings (OSTI)

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.

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

2007-07-01T23:59:59.000Z

87

Enhancement of electromagnetic propagation through complex media for Radio Frequency Identification  

E-Print Network (OSTI)

In this thesis, I present and examine the fundamental limitations involved in Radio Frequency Identification (RFID) as well as provide a means to improve reader-tag communication in ultra high frequency RFID systems. The ...

Marti, Uttara P

2005-01-01T23:59:59.000Z

88

Free-Free Emission at Low Radio Frequencies  

E-Print Network (OSTI)

We discuss free-free radio emission from ionized gas in the intergalactic medium. Because the emissivity is proportional to the square of the electron density, the mean background is strongly sensitive to the spatial clumping of free electrons. Using several existing models for the clumping of ionized gas, we find that the expected free-free distortion to the cosmic microwave background (CMB) blackbody spectrum is at a level detectable with upcoming experiments such as the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE). However, the dominant contribution to the distortion comes from clumpy gas at z free-free background and the extent to which these anisotropies confuse the search for fluctuations in 21 cm line emission from neutral hydrogen during and prior to reionization. This background is smooth in frequency space and hence can be removed through frequency differencing, but only so long as the 21 cm signal and the free-free emission are uncorrelated. We show that, because the free-free background is generated primarily at low redshifts, the cross-correlation between the two fields is smaller than a few percent. Thus, multifrequency cleaning should be an effective way to eliminate the free-free confusion.

Asantha Cooray; Steven Furlanetto

2004-02-10T23:59:59.000Z

89

Proposal for the Purchase, Without a Call for Tenders, of a Fourth Radio-Frequency Transmission Line for the SPS  

E-Print Network (OSTI)

Proposal for the Purchase, Without a Call for Tenders, of a Fourth Radio-Frequency Transmission Line for the SPS

1977-01-01T23:59:59.000Z

90

Radio frequency discharge with control of plasma potential distribution  

Science Conference Proceedings (OSTI)

A RF discharge plasma generator with additional electrodes for independent control of plasma potential distribution is proposed. With positive biasing of this ring electrode relative end flanges and longitudinal magnetic field a confinement of fast electrons in the discharge will be improved for reliable triggering of pulsed RF discharge at low gas density and rate of ion generation will be enhanced. In the proposed discharge combination, the electron energy is enhanced by RF field and the fast electron confinement is improved by enhanced positive plasma potential which improves the efficiency of plasma generation significantly. This combination creates a synergetic effect with a significantly improving the plasma generation performance at low gas density. The discharge parameters can be optimized for enhance plasma generation with acceptable electrode sputtering.

Dudnikov, Vadim [Muons, Inc., Batavia, Illinois 60510 (United States); Dudnikov, A. [BINP, Novosibirsk 63090 (Russian Federation)

2012-02-15T23:59:59.000Z

91

Surface plasma source with saddle antenna radio frequency plasma generator  

Science Conference Proceedings (OSTI)

A prototype RF H{sup -} surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA/kW. Control experiments with H{sup -} beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

Dudnikov, V.; Johnson, R. P. [Muons, Inc., Batavia, Illinios 60510 (United States); Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, Tennessee 37831 (United States)

2012-02-15T23:59:59.000Z

92

Bootstrap currents in radio-frequency-driven tokamak equilibria  

SciTech Connect

Interest in the bootstrap current arising from neoclassical transport in tokamaks has increased recently in view of certain experimental observations. In this study, the bootstrap current is calculated for a number of rf current-driven tokamaks. Two-dimensional, self-consistent, steady-state tokamak MHD equilibria are obtained by including both the transport-driven bootstrap current and the externally driven rf current. The self-consistency is acomplished by iterating between two-dimensional MHD equilibrium calculations and the current calculations (including bootstrap and rf ray-tracing). Calculations for other reactor parameters of interest are also carried out. It is found that for reactor-grade plasmas, the bootstrap current contribution to the toroidal current is, in general, important. An approxiamte scaling law for GAMMA, based on parametric survey performed, is also obtained. 16 refs., 8 figs., 1 tab.

Hsiao, Ming-Yuan; Ehst, D.A.; Evans, K. Jr.

1988-05-01T23:59:59.000Z

93

A superconducting bandpass delta-sigma modulator for direct analog-to-digital conversion of microwave radio  

E-Print Network (OSTI)

Direct analog-to-digital conversion of multi-GHz radio frequency (RF) signals is the ultimate goal in software radio receiver design but remains a daunting challenge for any technology. This thesis examines the potential ...

Bulzacchelli, John F. (John Francis)

2003-01-01T23:59:59.000Z

94

A Study of Microfluidic Reconfiguration Mechanisms Enabled by Functionalized Dispersions of Colloidal Material for Radio Frequency Applications  

E-Print Network (OSTI)

Communication and reconnaissance systems are requiring increasing flexibility concerning functionality and efficiency for multiband and broadband frequency applications. Circuit-based reconfiguration mechanisms continue to promote radio frequency (RF) application flexibility; however, increasing limitations have resulted in hindering performance. Therefore, the implementation of a "wireless" reconfiguration mechanism provides the required agility and amicability for microwave circuits and antennas without local overhead. The wireless reconfiguration mechanism in this thesis integrates dynamic, fluidic-based material systems to achieve electromagnetic agility and reduce the need for "wired" reconfiguration technologies. The dynamic material system component has become known as electromagnetically functionalized colloidal dispersions (EFCDs). In a microfluidic reconfiguration system, they provide electromagnetic agility by altering the colloidal volume fraction of EFCDs - their name highlights the special considerations we give to material systems in applied electromagnetics towards lowering loss and reducing system complexity. Utilizing EFCDs at the RF device-level produced the first circuit-type integration of this reconfiguration system; this is identified as the coaxial stub microfluidic impedance transformer (COSMIX). The COSMIX is a small hollowed segment of transmission line with results showing a full reactive loop (capacitive to inductive tuning) around the Smith chart over a 1.2 GHz bandwidth. A second microfluidic application demonstrates a novel antenna reconfiguration mechanism for a 3 GHz microstrip patch antenna. Results showed a 300 MHz downward frequency shift by dielectric colloidal dispersions. Magnetic material produced a 40 MHz frequency shift. The final application demonstrates the dynamically altering microfluidic system for a 3 GHz 1x2 array of linearly polarized microstrip patch antennas. The parallel microfluidic capillaries were imbedded in polydimethylsiloxane (PDMS). Both E- and H-plane designs showed a 250 MHz frequency shift by dielectric colloidal dispersions. Results showed a strong correlation between decreasing electrical length of the elements and an increase of the volume fraction, causing frequency to decrease and mutual coupling to increase. Measured, modeled, and analytical results for impedance, voltage standing wave ratio (VSWR), and radiation behavior (where applicable) are provided.

Goldberger, Sean A.

2009-05-01T23:59:59.000Z

95

Adaptive-rate techniques for frequency-hop multiple-access packet-radio networks  

E-Print Network (OSTI)

The effects of adaptive-rate transmissions and routing on the total throughput of a slow-frequency-hop packet-radio network are considered. Adaptive rates are achieved through the use of error-control coding with perfect ...

Block, Frederick J., IV

96

A Radio Frequency Identification (RFID) evaluation strategy for customer fulfillment centers  

E-Print Network (OSTI)

Radio Frequency Identification (RFID) is a wireless technology that can be used to track inventory labeled with microchip-embedded identifiers communicating passively with scanners without operator involvement. This ...

Shen, Howard H. (Howard Hao)

2006-01-01T23:59:59.000Z

97

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

SciTech Connect

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.

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

98

A Survey of the Urban RF Environment  

Science Conference Proceedings (OSTI)

The prevalence of sources of radio-frequency (RF) electromagnetic fields is expanding at a rapid pace.  As new wireless technologies are deployed (e.g., smart meters), questions are often raised as to what extent people are exposed to their RF emissions, and what if any effects on health and safety the RF could possibly cause. To obtain a frame of reference for the contributions of new sources to our environment, this study was designed to quantify the levels of RF fields that already exist in ...

2012-12-31T23:59:59.000Z

99

R.F. heating near the lower hybrid frequency in the FM-1 spherator  

SciTech Connect

Plasma heating experiments at frequencies near the lower hybrid frequency have been carried out at modest powers (.05 to 4kW). The antenna structure operating at 68 MHz was comprised of two plates driven out of phase on the exterior of the plasma. High electron heating efficiency (greater than 40 percent) in both helium and argon plasmas was observed with only a weak density dependence. At low densities (n/sub e/ less than or equal to 1 x 10$sup 11$ cm$sup -3$), the heating was uniform across the plasma while at higher densities the heating was preferentially on the exterior portion of the plasma. The heating of the exterior of the plasma was found not to correspond to absorption at the lower hybrid resonance layer. The electron heating efficiency was found to be a weak function of rf power when the incident rf power was varied from 1 to 15 times the experimentally observed threshold power for parametric instabilities. Ion temperatures were determined by measuring the Doppler broadening of an Argon ion line using a Fabry-Perot interferometer. Low efficiency main body ion heating (1 to 3 percent) was observed. (auth)

Hawryluk, R.J.; Davis, S.L.; Schmidt, J.A.

1975-12-01T23:59:59.000Z

100

Design of compact frequency synthesizer for self-calibration in RF circuits  

E-Print Network (OSTI)

A compact frequency synthesizer based on a phase locked loop (PLL) is designed for the self-calibration in RF circuits. The main advantage of the presented frequency synthesizer is that it can be built in a small silicon area using MOSFET interface trap charge pump (ITCP) current generators. The ITCP current generator makes it possible to use small currents at nano-ampere levels so that small capacitances can be used in the loop filter. A large resistance, which is required to compensate for the reduced capacitances, is implemented using an operational transconductance amplifier (OTA). An ITCP current generator is used as a tail current source for the OTA in order to realize a small transconductance. The presented frequency synthesizer has the output frequency range from 570 MHz to 600 MHz with a 100 KHz frequency step. Total silicon area is about 0.3 mm2 using AMIS 0.5 ??m CMOS technology, and the power consumption is 26.7 mW with 3 V single power supply.

Park, Sanghoon

2004-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

CMOS injection locked oscillators for quadrature generation at radio-frequency  

Science Conference Proceedings (OSTI)

The design of quadrature local oscillators for CMOS wireless transceivers is still one of the most challenging issues. This paper focuses the advantages of injection locking techniques to achieve high-performance quadrature generators. A synchronizing ... Keywords: CMOS RF integrated circuits, Frequency dividers, Injection locking, Phase noise, Quadrature local oscillators, VCO

Andrea Mazzanti; Francesco Svelto

2006-11-01T23:59:59.000Z

102

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

E-Print Network (OSTI)

TDD) only, but frequency-division duplexing (FDD) as wellas half-duplex FDD is also supported for the fixed WiMAX

Park, Sanghoon

2010-01-01T23:59:59.000Z

103

Measurements of time average series resonance effect in capacitively coupled radio frequency discharge plasma  

Science Conference Proceedings (OSTI)

Self-excited plasma series resonance is observed in low pressure capacitvely coupled radio frequency discharges as high-frequency oscillations superimposed on the normal radio frequency current. This high-frequency contribution to the radio frequency current is generated by a series resonance between the capacitive sheath and the inductive and resistive bulk plasma. In this report, we present an experimental method to measure the plasma series resonance in a capacitively coupled radio frequency argon plasma by modifying the homogeneous discharge model. The homogeneous discharge model is modified by introducing a correction factor to the plasma resistance. Plasma parameters are also calculated by considering the plasma series resonances effect. Experimental measurements show that the self-excitation of the plasma series resonance, which arises in capacitive discharge due to the nonlinear interaction of plasma bulk and sheath, significantly enhances both the Ohmic and stochastic heating. The experimentally measured total dissipation, which is the sum of the Ohmic and stochastic heating, is found to increase significantly with decreasing pressure.

Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H. [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Ave. Vicuna Mackenna 4860, Santiago 22 (Chile); Kakati, M. [Thermal Plasma Processed Materials Laboratory, Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402, Assam (India)

2011-10-15T23:59:59.000Z

104

A Perspective on Radio-Frequency Exposure Associated With Residential Automatic Meter Reading Technology  

Science Conference Proceedings (OSTI)

Advanced Metering Infrastructure (AMI) is rapidly expanding to improve the service quality and efficiency of our electrical power systems. This short paper focuses on questions that have arisen with regard to residential radio-frequency exposure from Automatic Meter Reading technology (or the use of so-called Smart Meters), a component of AMI, which over time is replacing conventional electrical meters.

2010-02-22T23:59:59.000Z

105

A new method for indoor location base on radio frequency identification  

Science Conference Proceedings (OSTI)

In recent years, there has dramatic proliferation of research concerned with Radio Frequency Identification (RFID). The RFID technologies are getting considerable attentions not only academic research but also the applications of enterprise. One of most ... Keywords: LANDMRC, RFID, RSS, indoor position location, location identification, powel level

Rung-Ching Chen; Sheng-Ling Huang

2009-07-01T23:59:59.000Z

106

The effect of radio frequency plasma processing reactor circuitry on plasma characteristics  

E-Print Network (OSTI)

, developed an equivalent circuit model of the plasma reactor using this data, and later devel- oped a sheath was supported by the National Institute of Standards and Technology, Air Force Office of Scientific ResearchThe effect of radio frequency plasma processing reactor circuitry on plasma characteristics Shahid

Kushner, Mark

107

Contributions to Radio Frequency Identification (RFID) research: An assessment of SCI-, SSCI-indexed papers from 2004 to 2008  

Science Conference Proceedings (OSTI)

The research literature on Radio Frequency Identification (RFID) has grown exponentially in recent years. In a domain where new concepts and techniques are constantly being introduced, it is of interest to analyze recent trends in this literature. Although ... Keywords: Citation analysis, Radio Frequency Identification (RFID), Science Citation Index (SCI), Social Science Citation Index (SSCI)

Wei-Pang Liao; Tom M. Y. Lin; Shu-Hsien Liao

2011-01-01T23:59:59.000Z

108

Radio frequency circuits for wireless receiver front-ends  

E-Print Network (OSTI)

The beginning of the 21st century sees great development and demands on wireless communication technologies. Wireless technologies, either based on a cable replacement or on a networked environment, penetrate our daily life more rapidly than ever. Low operational power, low cost, small form factor, and function diversity are the crucial requirements for a successful wireless product. The receiver??s front-end circuits play an important role in faithfully recovering the information transmitted through the wireless channel. Bluetooth is a short-range cable replacement wireless technology. A Bluetooth receiver architecture was proposed and designed using a pure CMOS process. The front-end of the receiver consists of a low noise ampli?er (LNA) and mixer. The intermediate frequency was chosen to be 2MHz to save battery power and alleviate the low frequency noise problem. A conventional LNA architecture was used for reliability. The mixer is a modi?ed Gilbert-cell using the current bleeding technique to further reduce the low frequency noise. The front-end draws 10 mA current from a 3 V power supply, has a 8.5 dB noise ?gure, and a voltage gain of 25 dB and -9 dBm IIP3. A front-end for dual-mode receiver is also designed to explore the capability of a multi-standard application. The two standards are IEEE 802.11b and Bluetooth. They work together making the wireless experience more exciting. The front-end is designed using BiCMOS technology and incorporating a direct conversion receiver architecture. A number of circuit techniques are used in the front-end design to achieve optimal results. It consumes 13.6 mA from a 2.5 V power supply with a 5.5 dB noise ?gure, 33 dB voltage gain and -13 dBm IIP3. Besides the system level contributions, intensive studies were carried out on the development of quality LNA circuits. Based on the multi-gated LNA structure, a CMOS LNA structure using bipolar transistors to provide linearization is proposed. This LNA con?guration can achieve comparable linearity to its CMOS multi-gated counterpart and work at a higher frequency with less power consumption. A LNA using an on-chip transformer source degeneration is proposed to realize input impedance matching. The possibility of a dual-band cellular application is studied. Finally, a study on ultra-wide band (UWB) LNA implementation is performed to explore the possibility and capability of CMOS technology on the latest UWB standard for multimedia applications.

Xin, Chunyu

2004-08-01T23:59:59.000Z

109

FREQUENCY DEPENDENCE OF THE POWER-LAW INDEX OF SOLAR RADIO BURSTS  

Science Conference Proceedings (OSTI)

We process solar flare observations of Nobeyama Radio Polarimeters with an improved maximum likelihood method developed recently by Clauset et al. The method accurately extracts power-law behaviors of the peak fluxes in 486 radio bursts at six frequencies (1-35 GHz) and shows an excellent performance in this study. The power-law indices on 1-35 GHz given by this study vary around 1.74-1.87, which is consistent with earlier statistics in different solar cycles and very close to the simulations of the avalanche model by Lu.

Song Qiwu; Huang Guangli [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tan Baolin, E-mail: songqw@pmo.ac.cn, E-mail: glhuang@pmo.ac.cn, E-mail: bltan@bao.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2012-05-10T23:59:59.000Z

110

Matching network for RF plasma source  

DOE Patents (OSTI)

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.

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

2007-11-20T23:59:59.000Z

111

Robust RF Switch Yields Enhanced Communication Capabilities (ANL-IN-09-053 and ANL-IN-09-070)  

Scientists at Argonne National Laboratory have created a special radio frequency (RF) microelectromechanical system (MEMS) switch based on ultra nanocrystalline diamond (UNCD) as a dielectric that promises a next generation of military and commercial ...

112

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

DOE Patents (OSTI)

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.

Simpson, James E. (Gaithersburg, MD)

1999-01-01T23:59:59.000Z

113

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

DOE Patents (OSTI)

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.

Simpson, J.E.

1999-06-08T23:59:59.000Z

114

Computer simulation model development and validation for radio frequency (RF) heating of dry food materials  

E-Print Network (OSTI)

·11 /2 Tbsp whole wheat flour · 1 /2 Tbsp whole wheat flour and 1 /2 Tbsp all-purpose flour Flour, 1 flour, result in a rye flour or whole wheat flour and reduced volume 1 /2 cup all-purpose flour and a · 3 /4 cup whole wheat flour or bran heavier product. flour and 1 /4 cup all-purpose flour ·1 cup rye

Tang, Juming

115

Radio frequency plasma heating in large tokamak systems near the lower hybrid resonance  

SciTech Connect

The frequency range, power, efficiency, and pulse length of a high power rf system are discussed as they might be applied to the TFTR Tokamak facility as well as on a full scale reactor. Comparisons are made of the size, power output, and costs to obtain microwave power sufficient to satisfy the physics requirements. A new microwave feed concept is discussed which will improve the coupling of the microwave energy into the plasma. The unique advantages of waveguide feed systems is apparent when one considers the practical problems associated with coupling supplementary heating energy into a reactor. (auth)

Deitz, A.; Hooke, W.M.

1975-01-01T23:59:59.000Z

116

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

E-Print Network (OSTI)

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. ...

Oberoi, Divya

117

THE FERRITE BIASING SYSTEM FOR THE RADIO FREQUENCY CAVITIES OF THE PRINCETON-PENNSYLVANIA 3 Bev PROTON SYNCHROTRON  

SciTech Connect

A description is given of the ferrite biasing system for the four tuned radio frequency cavities of the synchrotron. Each ferrite loaded double cavity has a single turn bias winding which is driven to a peak current of 13,500 amperes by a push-pull transformer arrangement. There is automatic tap changing of the transformer to accommodate the variable impedance load (for power considerations). The programming and frequency response of the system have to be such that each cavity can operate as the reso nant circuit of a self tracking radio frequency amplifier over the frequency range 6.5 to 30 Mc at the 20 cps repetition rate of the synchrotron. Between acceleration cycles it is necessary to program the ferrite to a given magnetic state, near that of maximum radio frequency permeability. (auth)

Rees, G.H.

1962-08-29T23:59:59.000Z

118

Simulation of an RFQ (radio-frequency quadruple) funnel for heavy-ion beams  

Science Conference Proceedings (OSTI)

Use of the magnetic force to focus and deflect heavy-ion beams is marginal at low ion velocities. Low-emittance-growth funnels using discrete magnetic elements are difficult to design for these beams. We show that a new type of radio-frequency quadruple (RFQ) funnel is especially suitable for this application. Simulation procedures, which include space-charge and image effects, have produced a high-quality funnel design for 20-MeV Bi/sup +1/ ions. 4 refs., 4 figs., 2 tabs.

Guy, F.W.; Stokes, R.H.

1989-01-01T23:59:59.000Z

119

A new Main Injector radio frequency system for 2.3 MW Project X operations  

SciTech Connect

For Project X Fermilab Main Injector will be required to provide up to 2.3 MW to a neutrino production target at energies between 60 and 120 GeV. To accomplish the above power levels 3 times the current beam intensity will need to be accelerated. In addition the injection energy of Main Injector will need to be as low as 6 GeV. The current 30 year old Main Injector radio frequency system will not be able to provide the required power and a new system will be required. The specifications of the new system will be described.

Dey, J.; Kourbanis, I.; /Fermilab

2011-03-01T23:59:59.000Z

120

Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator  

SciTech Connect

The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described.

Williams, S.W.; Potter, J.M.

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Realization and modeling of rf superconducting quantum interference device metamaterials  

E-Print Network (OSTI)

We have prepared meta-atoms based on radio frequency superconducting quantum interference devices (RF SQUIDs) and examined their tunability with dc magnetic field, rf current, and temperature. RF SQUIDs are superconducting split ring resonators in which the usual capacitance is supplemented with a Josephson junction, which introduces strong nonlinearity in the rf properties. We find excellent agreement between the data and a model which regards the Josephson junction as the resistively and capacitively-shunted junction. A magnetic field tunability of 80 THz/Gauss at 12 GHz is observed, a total tunability of 56$%$ is achieved, and a unique electromagnetically-induced transparency feature at intermediate excitation powers is demonstrated for the first time. An RF SQUID metamaterial is shown to have qualitatively the same behavior as a single RF SQUID with regards to DC flux and temperature tuning.

M. Trepanier; Daimeng Zhang; Oleg Mukhanov; Steven M. Anlage

2013-08-06T23:59:59.000Z

122

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

E-Print Network (OSTI)

Within the first decade of the 21st century, the aerospace community has seen many more opportunities to launch small spacecraft in the 10 to 100 kg mass class. Coupled with this has been consistent interest from the government in developing small-spacecraft platforms to expand civil and military mission possibilities. Small spacecraft have also given small organizations such as universities an increased access to space. Because small satellites are limited in size, power, and mass, new and often nontraditional capabilities must be explored and developed to make them viable and attractive when compared with larger and more proven spacecraft. Moreover, small organizations that wish to contribute technically are often limited by the small size of their teams and available resources, and need creative solutions for meeting mission requirements. A key need is in space-to-ground communications. Complex missions typically require large amounts of data transfer to the ground and in a timely fashion. Available options trade hardware cost, available ground stations or networks, available operating-frequency range, data-rate performance, and ease of use. A system for small spacecraft will be presented based upon Radio Frequency Integrated Circuits (RFIC) that minimizes development effort and maximizes interface control to meet typical small-spacecraft communications requirements. RFICs are low-cost components that feature pre-built radio hardware on a chip that can be expanded easily by developers with little or no radio experience. These devices are widespread in domestic applications for short-range connectivity. A preliminary design and prototype is presented that meets basic spaceflight requirements, offers data rates in the 55 to 85 kbps range, and has completed basic proof-of-concept testing. While there are higher-data-rate alternatives in existence, the solution presented here strikes a useful balance among data rate, parts cost, and ease of use for non experts, and gives the user operational control necessary to make air-to-ground communications time effective.

Graves, John

2011-12-01T23:59:59.000Z

123

A computer program for HVDC converter station RF noise calculations  

SciTech Connect

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.

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

124

RF Cherenkov picosecond timing technique for high energy physics applications  

Science Conference Proceedings (OSTI)

The Cherenkov time-of-propagation (TOP) detector and Cherenkov time-of-flight (TOF) detector in a ?head-on? geometry based on the recently proposed time measuring technique with radio frequency (RF) phototube are considered. Results of the Monte Carlo simulations are presented.

Margaryan, Amur; Hashimoto, Osamu; Majewski, Stanislaw; Tang, Liguang

2008-09-01T23:59:59.000Z

125

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

Science Conference Proceedings (OSTI)

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.

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

2012-04-01T23:59:59.000Z

126

Laser polishing of niobium for application to superconducting radio frequency cavities  

SciTech Connect

Superconducting radio frequency niobium cavities are at the heart of an increasing number of particle accelerators. Their performance is dominated by a several nanometer thick layer at the interior surface. Maximizing the smoothness of this surface is critical, and aggressive chemical treatments are now employed to this end. The authors describe laser-induced surface melting as an alternative “greener” approach. Selection of laser parameters guided by modeling achieved melting that reduced the surface roughness from the fabrication process. The resulting topography was examined by scanning electron microscope and atomic force microscope (AFM). Plots of power spectral density computed from the AFM data give further insight into the effect of laser melting on the topography of the mechanically polished (only) niobium.

Senthil Singaravelu ,John Klopf, Chen Xu, Geoffrey Krafft, Michael Kelley

2012-09-01T23:59:59.000Z

127

Temperature distributions of radio-frequency plasma in water by spectroscopic analysis  

Science Conference Proceedings (OSTI)

Distributions of emission intensity from radicals, electron temperature, and rotational temperature at a radio frequency of 27.12 MHz plasma in water are clarified by detailed spectroscopy measurement. Through this investigation, the following were observed. The points of maximum emission intensity of Halpha, Hbeta, O (777 nm), and O (845 nm) are almost the same, while that of OH shifts upward. The electron temperature decreases, while the rotational temperature increases with pressure. The distribution of the electron temperature changes at a threshold pressure, which is concerned with a change in the electron discharge mechanism. The self-bias of the electrode changes from a negative to positive at a threshold pressure. The point of the maximum rotational temperature of OH radicals shifts to approximately 1 mm above that for the maximum intensity of OH emission.

Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Maehara, Tsunehiro; Abe, Fumiaki [Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Kawashima, Ayato [Faculty of Agriculture, Ehime University, Matsuyama 790-8566 (Japan)

2009-12-01T23:59:59.000Z

128

Investigation of the State and Uses of Ultra-Wide-Band Radio-Frequency Identification Technology  

SciTech Connect

Radio-frequency identification (RFID) technology has revolutionized the concept of asset tracking. By affixing an RFID tag to a valued asset, one can track the item throughout any facility where RIFD readers are in place, thereby alerting inspectors to theft, misuse, and misplacement of the tracked item. While not yet implemented for tracking very high value assets, RFID technology is already widely used in many industries as the standard for asset tracking. A subset of RFID technology exists called Ultra-Wide-Band (UWB) RFID. While traditional (sometimes called narrow-band) RFID technology transmits a continuous sine-wave signal of a narrow frequency range, UWB technology works by transmitting signals as short pulses of a broad frequency range. This improves performance in several areas, namely, range, precision, and accuracy of motion detection. Because of the nature of the technology, it also performs well in close proximity to metal, which sets it apart from traditional RFID. The purpose of this paper is to investigate the current state of UWB RFID technology and research the areas where it already is being used. This is accomplished through study of publicly known uses of the technology as well as personal exploration of RFID hardware and software. This paper presents the findings in a general manner to facilitate their usefulness for diverse applications.

Hickerson, Jonathan W [ORNL; Younkin, James R [ORNL

2010-01-01T23:59:59.000Z

129

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

E-Print Network (OSTI)

. 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

Cummer, Steven A.

130

Dust removal in radio-frequency plasmas by a traveling potential modulation  

Science Conference Proceedings (OSTI)

The dust contamination in plasma deposition processes plays a crucial role in the quality and the yield of the products. To improve the quality and the yield of plasma processing, a favorable way is to remove the dust particles actively from the plasma reactors.Our recent experiments in the striped electrode device show that a traveling plasma modulation allows for a systematic particle removal independent of the reactor size. Besides the rf powered electrode, the striped electrode device includes a segmented electrode that consists of 100 electrically insulated narrow stripes. A traveling potential profile is produced by the modulation of the voltage signals applied on the stripes. The dust particles are trapped in the potential wells and transported with the traveling of the potential profile.The particle-in-cell (PIC) simulation on the potential above the segmented electrode indicates that the traveling potential profile can be realized either by applying low-frequency (0.1-10 Hz) voltage signals with a fixed phase shift between adjacent stripes or high-frequency (10 kHz a circumflex AS 100 MHz) signals with the amplitudes modulated by a low-frequency envelope. The transportation of the dust particles is simulated with a two-dimensional molecular dynamics (MD) code with the potential profile obtained from the PIC simulation. The MD results reproduce the experimental observations successfully.This technology allows for an active removal of the contaminating particles in processing plasmas and it is independent of the reactor size. The removal velocity is controllable by adjusting the parameters for the modulation.

Li Yangfang; Jiang Ke; Thomas, Hubertus M.; Morfill, Gregor E. [Max-Planck-Institute for Extraterrestrial Physics, 85748 Garching (Germany)

2010-06-16T23:59:59.000Z

131

High voltage RF feedthrough bushing  

DOE Patents (OSTI)

Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, Glenn F. (Huntington Station, NY)

1984-01-01T23:59:59.000Z

132

High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency thermal plasma  

E-Print Network (OSTI)

by liquid spray injection of disilanes into an argon­hydrogen RF plasma operat- ing at 20­40 kPa [4]. Here

Zachariah, Michael R.

133

Initial RF measurements of the CW normal-conducting RF injector  

Science Conference Proceedings (OSTI)

The LANL 2.5-cell, normal-conducting radio-frequency (NCRF) injector has been fabricated. We present initial results of low-power RF measurements (cavity Q, cavity field map, coupling beta, etc.) of the NCRF injector. The measured cavity Q and relative fields are found to be in good agreement with the design calculations and earlier measurements of Glidcop properties. However, the coupling beta of the ridge-loaded waveguides is found to be significantly higher than the design point. The impact of these low-power measurement results on the planned high-power RF and electron beam tests will be discussed.

Krawcyk, Frank L [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Martinez, Felix A [Los Alamos National Laboratory; Nguyen, Dinh C [Los Alamos National Laboratory; Bolme, Gerald [Los Alamos National Laboratory; Young, Karen [Los Alamos National Laboratory; Toung, Lloyd [AES

2008-01-01T23:59:59.000Z

134

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

SciTech Connect

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.

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

135

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

Science Conference Proceedings (OSTI)

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.

Ward,R.; Rosenthal,M.

2009-07-12T23:59:59.000Z

136

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

SciTech Connect

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.

JOE,J.

2007-07-08T23:59:59.000Z

137

Three dimensional complex plasma structures in a combined radio frequency and direct current discharge  

E-Print Network (OSTI)

We report on the first detailed analysis of large three dimensional (3D) complex plasma structures in experiments performed in pure rf and combined rf+dc discharge modes. Inductively coupled plasma (ICP) is generated by an rf coil wrapped around the vertically positioned cylindrical glass tube at a pressure of 0.3 mbar. In addition, dc plasma can be generated by applying voltage to the electrodes at the ends of the tube far from the rf coil. The injected monodisperse particles are levitated in the plasma below the coil. A scanning laser sheet and a high resolution camera are used to determine the 3D positions of about $10^5$ particles. The observed bowl-shaped particle clouds reveal coexistence of various structures, including well-distinguished solid-like, less ordered liquid-like, and pronounced string-like phases. New criteria to identify string-like structures are proposed.

S. Mitic; B. A. Klumov; S. A. Khrapak; G. E. Morfill

2013-04-03T23:59:59.000Z

138

Influence of the power on the particles generated in a low pressure radio frequency nitrogen-rich methane discharge  

SciTech Connect

Particles are generated in low pressure radio frequency (13.56 MHz) CH{sub 4}/N{sub 2} discharges containing 90% of nitrogen. The influence of the radio frequency power supply on the particle presence within the plasma is studied. Particles are evidenced by laser light scattering. The particle formation leads to modifications in the discharge electrical parameters such as the dc self-bias voltage and the phase angle third harmonic. The plasma is analyzed by optical emission spectroscopy by following the temporal evolution of excited species such as CN, N{sub 2}, N{sub 2}{sup +}, Ar, and He. Finally, the particle morphology and size are analyzed by scanning electron microscopy. The correlation between these results allows a better understanding of the power influence on the particle growth within the plasma.

Massereau-Guilbaud, Veronique; Pereira, Jeremy; Geraud-Grenier, Isabelle; Plain, Andre [GREMI, Groupe de Recherches sur l'Energetique des Milieux Ionises, UMR6606, CNRS/Universite d' Orleans, Site de Bourges, Rue G. Berger, BP 4043, 18028 Bourges Cedex (France)

2009-02-01T23:59:59.000Z

139

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

DOE Patents (OSTI)

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.

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

1994-06-28T23:59:59.000Z

140

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

DOE Patents (OSTI)

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.

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

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

RF system models for the CERN Large Hadron Collider with application to longitudinal dynamics  

Science Conference Proceedings (OSTI)

The LHC RF station-beam interaction strongly influences the longitudinal beam dynamics, both single bunch and collective effects. Non-linearities and noise generated within the Radio Frequency (RF) accelerating system interact with the beam and contribute to beam motion and longitudinal emittance blowup. Thus, the noise power spectrum of the RF accelerating voltage strongly affects the longitudinal beam distribution. Furthermore, the coupled-bunch instabilities are also directly affected by the RF components and the configuration of the Low Level RF (LLRF) feedback loops. In this work we present a formalism relating the longitudinal beam dynamics with the RF system configurations, an estimation of collective effects stability margins, and an evaluation of longitudinal sensitivity to various LLRF parameters and configurations.

Mastorides, T.; Rivetta, C.; Fox, J.D.; Winkle, D.Van; /SLAC; Baudrenghien, P.; /CERN

2011-03-03T23:59:59.000Z

142

Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas  

SciTech Connect

A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

O'Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

2012-10-08T23:59:59.000Z

143

Phase stable rf transport system  

DOE Patents (OSTI)

This invention is comprised of an RF transport system which 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.

Curtin, M.T.; Natter, E.F.; Denney, P.M.

1991-02-19T23:59:59.000Z

144

Phase stable RF transport system  

DOE Patents (OSTI)

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.

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

1992-01-01T23:59:59.000Z

145

ANALYZING SURFACE ROUGHNESS DEPENDENCE OF LINEAR RF LOSSES  

SciTech Connect

Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB, W& M College; Xu, Chen [JLAB, W& M College

2012-09-01T23:59:59.000Z

146

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

Science Conference Proceedings (OSTI)

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.

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

147

Radio-frequency emission from an explosive instability in an electron beam  

SciTech Connect

The explosive instability which occurs when an electron beam moves through a helical resonator is studied. This instability can be exploited to generate rf oscillations at high efficiency (20% in these experiments). The spectral width is narrower than the characteristic width for linear instabilities.

Buts, V.A.; Izmailov, A.N.

1978-07-01T23:59:59.000Z

148

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

Science Conference Proceedings (OSTI)

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.

Burnham, A K

2003-08-20T23:59:59.000Z

149

Acceleration of ordering transformation of a new Fe{sub 2}(Mn,Cr)Si Heusler-alloy film by very high frequency plasma irradiation process during radio frequency sputter deposition  

Science Conference Proceedings (OSTI)

A new Heusler alloy, Fe{sub 2}(Mn,Cr)Si, that is likely to have high spin polarization (P) and high damping constant ({alpha}) was proposed to obtain high magneto-resistance ratio and low spin torque noise in a magnetic read head with a current-perpendicular-to-plane (CPP) giant magneto-resistance (GMR) multilayer. A very high frequency (VHF) plasma irradiation process during radio frequency (RF) sputter deposition was investigated to form the highly ordered structure of the Heusler alloy film with low thermal treatment temperature. The main results are as follows: (1) P and magnetic moment of Fe{sub 2}(Mn{sub 0.5}Cr{sub 0.5})Si with an L2{sub 1} structure were estimated at 0.99 and 2.49 {mu}{sub B}/f.u., respectively, and {alpha} was also estimated to be larger compared with the case of Co{sub 2}MnSi, according to density of states (DOS) calculations. (2) The ordering (at least B2 structure) temperature of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film decreased from 500 to 300 deg. C by using the VHF plasma irradiation process with optimized condition. (3) The surface roughness of Fe{sub 2}(Mn{sub 0.6}Cr{sub 0.4})Si film also reduced from 1.7 to 0.5 nm by using the VHF plasma irradiation process. It is found that the Fe{sub 2}(Mn,Cr)Si Heusler alloy and the VHF plasma irradiation process with optimized condition seems to be applicable for fabrication of high-performance magnetic read head with CPP-GMR device.

Yoshimura, S.; Kobayashi, H.; Egawa, G.; Saito, H. [Center for Geo-environmental Science, Graduate School of Engineering and Resource Science, Akita University, Akita, 010-8502 (Japan); Ishida, S. [Department of Physics, Graduate School of Science and Engineering, Kagoshima University, Kagoshima, 890-8580 (Japan)

2011-04-01T23:59:59.000Z

150

Radio-frequency integrated-circuit design for CMOS single-chip UWB systems  

E-Print Network (OSTI)

Low cost, a high-integrated capability, and low-power consumption are the basic requirements for ultra wide band (UWB) system design in order for the system to be adopted in various commercial electronic devices in the near future. Thus, the highly integrated transceiver is trended to be manufactured by companies using the latest silicon based complimentary metal-oxide-silicon (CMOS) processes. In this dissertation, several new structural designs are proposed, which provide solutions for some crucial RF blocks in CMOS for UWB for commercial applications. In this dissertation, there is a discussion of the development, as well as an illustration, of a fully-integrated ultra-broadband transmit/receive (T/R) switch which uses nMOS transistors with deep n-well in a standard 0.18-?m CMOS process. The new CMOS T/R switch exploits patterned-ground-shield on-chip inductors together with MOSFET’s parasitic capacitances in order to synthesize artificial transmission lines which result in low insertion loss over an extremely wide bandwidth. Within DC-10 GHz, 10-18 GHz, and 18-20 GHz, the developed CMOS T/R switch exhibits insertion loss of less than 0.7, 1.0 and 2.5 dB and isolation between 32-60 dB, 25-32 dB, and 25-27 dB, respectively. The measured 1-dB power compression point and input third-order intercept point reach as high as 26.2 and 41 dBm, respectively. Further, there is a discussion and demonstration of a tunable Carrier-based Time-gated UWB transmitter in this dissertation which uses a broadband multiplier, a novel fully integrated single pole single throw (SPST) switch designed by the CMOS process, where a tunable instantaneous bandwidth from 500 MHz to 4 GHz is exhibited by adjusting the width of the base band impulses in time domain. The SPST switch utilizes the synthetic transmission line concept and multiple reflections technique in order to realize a flat insertion loss less than 1.5 dB from 3.1 GHz to 10.6 GHz and an extremely high isolation of more than 45 dB within this frequency range. A fully integrated complementary LC voltage control oscillator (VCO), designed with a tunable buffer, operates from 4.6 GHz to 5.9 GHz. The measurement results demonstrate that the integrated VCO has a very low phase noise of –117 dBc/ Hz at 1 MHz offset. The fully integrated VCO achieves a very high figure of merit (FOM) of 183.5 using standard CMOS process while consuming 4 mA DC current.

Jin, Yalin

2008-05-01T23:59:59.000Z

151

Overview and status of RF systems for the SSC Linac  

SciTech Connect

The Superconducting Super Collider (SSC) Linear Accelerator (Linac) produces a 600-MeV, 35-{mu}s, H-beam at a 10-Hz repetition rate. The beam is accelerated by a series of RF cavities. These consist of a Radio Frequency Quadrupole (RFQ), two bunchers, and four Drift Tube Linac (DTL) tanks at 427.617 MHz, and two bunchers, nine side-coupled Linac modules, and an energy compressor at 1282.851 MHz. The RFQ amplifier and the low-frequency buncher cavity amplifiers use gridded tubes, while the other cavities use klystron amplifier systems. The RF control system consists of a reference line and cavity feedback and feedforward loops for each amplifier. The RF amplifier system for each of these accelerator cavities is described, and the current status of each system is presented.

Mynk, J.; Grippe, J.; Cutler, R.I.; Rodriguez, R.

1993-05-01T23:59:59.000Z

152

Fluid modeling of radio frequency and direct currents in a biased magnetized plasma  

SciTech Connect

This model aims at simulating a magnetized plasma column connected on one side to a probe and on the other side to an ICRH (Ion Cyclotron Resonant Heating) antenna. This is a double probe modeling of a plasma flux tube exchanging perpendicular currents: rf polarization current and dc currents (inertia, viscous, and friction) perpendicular to the magnetic field. A self consistent solution for the rectified potential and the density is obtained under the assumptions of flute hypothesis, inertialess electrons, and no collision in parallel direction. The main effect of rf biasing on the antenna side is to shift the IV characteristic so that the floating potential can be increased up to ln(I{sub 0}(eV{sub rf}/(k{sub B}T{sub e}))), with I{sub 0} the modified Bessel function of the first kind. On the contrary, the effect of dc currents is to decrease the plasma potential and the sheath potential which can be lower than 3k{sub B}T{sub e}/e or even be negative. Experimental characteristics are well matched by the 1D fluid code and exhibit very high negative currents (more than 30 j{sub i} the ion saturation current) for high positive biasing of the probe and for long flux tube (10 m). The non-saturation of the electron current is here due to high transverse transport enhanced by convective fluxes and dc currents able to bring an amount of density around the biased flux tube. During comparisons with experiments, the floating potential measured by a reciprocating probe is recovered by the code revealing that for a 120 V measured peak potential on the probe, the rf potential on the ICRH antenna is twice this value. Finally, the density profile can be flattened or steepened as a function of the transverse dc current direction.

Faudot, E.; Heuraux, S. [IJL-P2M UMR 7198 CNRS, F-54506 Vandoeuvre les Nancy, IJL, P2M-Faculte des Sciences, Vandoeuvre les Nancy 54506 (France); Kubic, M.; Gunn, J.; Colas, L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

2013-04-15T23:59:59.000Z

153

Use of a Geographic Mapping Tool in Power Line Routing for RF Hazard Identification: A Feasibility Evaluation  

Science Conference Proceedings (OSTI)

Radiofrequency (RF) fields induce currents and voltages on conductive objects with the general finding that larger or longer or taller objects, such as power lines and tall cranes, can result in greater currents and voltages. Medium wave frequencies (MF) associated with operation of AM radio broadcast stations are particularly prone to induction of RF voltages on long and/or tall cables that present the potential for arcing to ground or personnel who may initiate contact with the conductor. MF includes t...

2011-11-16T23:59:59.000Z

154

The development of the radio frequency driven negative ion source for neutral beam injectors (invited)  

Science Conference Proceedings (OSTI)

Large and powerful negative hydrogen ion sources are required for the neutral beam injection (NBI) systems of future fusion devices. Simplicity and maintenance-free operation favors RF sources, which are developed intensively at the Max-Planck-Institut fuer Plasmaphysik (IPP) since many years. The negative hydrogen ions are generated by caesium-enhanced surface conversion of atoms and positive ions on the plasma grid surface. With a small scale prototype the required high ion current density and the low fraction of co-extracted electrons at low pressure as well as stable pulses up to 1 h could be demonstrated. The modular design allows extension to large source dimensions. This has led to the decision to choose RF sources for the NBI of the international fusion reactor, ITER. As an intermediate step towards the full size ITER source at IPP, the development will be continued with a half-size source on the new ELISE testbed. This will enable to gain experience for the first time with negative hydrogen ion beams from RF sources of these dimensions.

Kraus, W.; Fantz, U.; Franzen, P.; Froeschle, M.; Heinemann, B.; Riedl, R.; Wuenderlich, D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany)

2012-02-15T23:59:59.000Z

155

Radio frequency dc-dc converters : device characterization, topology evaluation, and design  

E-Print Network (OSTI)

High frequency power conversion is attractive for the opportunities it affords for improved performance. Dc-dc converters operating at high frequencies use smaller-valued energy storage elements, which tend to be physically ...

Leitermann, Olivia

2008-01-01T23:59:59.000Z

156

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

DOE Patents (OSTI)

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.

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

157

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

DOE Patents (OSTI)

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.

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

2006-09-12T23:59:59.000Z

158

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

DOE Patents (OSTI)

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.

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

2006-04-04T23:59:59.000Z

159

Radio frequency magnetron sputter deposition of CaF{sub 2} films  

Science Conference Proceedings (OSTI)

Calcium fluoride films have been deposited onto unheated ({lt}100{degree}C) substrates by low power rf magnetron sputtering of CaF{sub 2} targets using Ar and Ne process gases at pressures of 0.5{endash}2.7 Pa, biased and floating substrate potentials, and various geometries of the substrate with respect to the source. The thickness and composition of the films are very sensitive to resputtering of the growing film. Uniform and stoichiometric films were most readily obtained on off-axis substrates using two sputter sources oriented with the targets facing each other. The films were found to be crystalline, have a fine textured microstructure, and to be transparent and highly resistive. {copyright} {ital 1998 American Vacuum Society.}

Dudney, N.J. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6030 (United States)

1998-03-01T23:59:59.000Z

160

Localized electrical fine tuning of passive microwave and radio frequency devices  

DOE Patents (OSTI)

A method and apparatus for the localized electrical fine tuning of passive multiple element microwave or RF devices in which a nonlinear dielectric material is deposited onto predetermined areas of a substrate containing the device. An appropriate electrically conductive material is deposited over predetermined areas of the nonlinear dielectric and the signal line of the device for providing electrical contact with the nonlinear dielectric. Individual, adjustable bias voltages are applied to the electrically conductive material allowing localized electrical fine tuning of the devices. The method of the present invention can be applied to manufactured devices, or can be incorporated into the design of the devices so that it is applied at the time the devices are manufactured. The invention can be configured to provide localized fine tuning for devices including but not limited to coplanar waveguides, slotline devices, stripline devices, and microstrip devices.

Findikoglu, Alp T. (Los Alamos, NM)

2001-04-10T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The magnetic field along the jets of NGC 4258 as deduced from high frequency radio observations  

E-Print Network (OSTI)

We present 2.4" resolution, high sensitivity radio continuum observations of the nearby spiral galaxy NGC 4258 in total intensity and linear polarization obtained with the Very Large Array at 3.6 cm (8.44 GHz). The radio emission along the northern jet and the center of the galaxy is polarized and allows investigation of the magnetic field. Assuming energy-equipartition between the magnetic field and the relativistic particles and distinguishing between (1) a relativistic electron-proton jet and (2) a relativistic electron-positron jet, we obtain average magnetic field strengths of about (1) 310\\muG and (2) 90\\muG. The rotation measure is determined to range from -400 to -800 rad/m^2 in the northern jet. Correcting the observed E-vectors of polarized intensity for Faraday rotation, the magnetic field along the jet turns out to be orientated mainly along the jet axis. An observed tilt with respect to the jet axis may indicate also a toroidal magnetic field component or a slightly helical magnetic field around the northern jet.

M. Krause; A. L"ohr

2004-03-05T23:59:59.000Z

162

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

E-Print Network (OSTI)

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 ...

Jurkov, Alexander S

2013-01-01T23:59:59.000Z

163

Probing the Climatological Impact of a Cosmic Ray-Cloud Connection through Low-Frequency Radio Observations  

E-Print Network (OSTI)

It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...

Magee, Nathan

2011-01-01T23:59:59.000Z

164

Energetic electron avalanches and mode transitions in planar inductively coupled radio-frequency driven plasmas operated in oxygen  

Science Conference Proceedings (OSTI)

Space and phase resolved optical emission spectroscopic measurements reveal that in certain parameter regimes, inductively coupled radio-frequency driven plasmas exhibit three distinct operation modes. At low powers, the plasma operates as an alpha-mode capacitively coupled plasma driven through the dynamics of the plasma boundary sheath potential in front of the antenna. At high powers, the plasma operates in inductive mode sustained through induced electric fields due to the time varying currents and associated magnetic fields from the antenna. At intermediate powers, close to the often observed capacitive to inductive (E-H) transition regime, energetic electron avalanches are identified to play a significant role in plasma sustainment, similar to gamma-mode capacitively coupled plasmas. These energetic electrons traverse the whole plasma gap, potentially influencing plasma surface interactions as exploited in technological applications.

Zaka-ul-Islam, M.; Niemi, K. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland (United Kingdom); Gans, T.; O'Connell, D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland (United Kingdom); York Plasma Institute, Department of Physics, University of York, Innovation Way, Heslington York YO10 5DQ (United Kingdom)

2011-07-25T23:59:59.000Z

165

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

DOE Green Energy (OSTI)

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.

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

1991-01-01T23:59:59.000Z

166

Origin of stress in radio frequency magnetron sputtered zinc oxide thin films  

SciTech Connect

Highly c-axis oriented ZnO thin films have been deposited on silicon substrates by planar rf magnetron sputtering under varying pressure (10-50 mTorr) and oxygen percentage (50-100%) in the reactive gas (Ar + O{sub 2}) mixture. The as-grown films were found to be stressed over a wide range from -1 x 10{sup 11} to -2 x 10{sup 8} dyne/cm{sup 2} that in turn depends strongly on the processing conditions, and the film becomes stress free at a unique combination of sputtering pressure and reactive gas composition. Raman spectroscopy and photoluminescence (PL) analyses identified the origin of stress as lattice distortion due to defects introduced in the ZnO thin film. FTIR study reveals that Zn-O bond becomes stronger with the increase in oxygen fraction in the reactive gas mixture. The lattice distortion or stress depends on the type of defects introduced during deposition. PL spectra show the formation of a shoulder in band emission with an increase in the processing pressure and are related to the presence of stress. The ratio of band emission to defect emission decreases with the increase in oxygen percentage from 50 to 100%. The studies show a correlation of stress with the structural, vibrational, and photoluminescence properties of the ZnO thin film. The systematic study of the stress will help in the fabrication of efficient devices based on ZnO film.

Menon, Rashmi; Gupta, Vinay; Sreenivas, K. [Electronic Material and Devices Laboratory, Department of Physics and Astrophysics, University of Delhi, Delhi 11007 (India); Tan, H. H.; Jagadish, C. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

2011-03-15T23:59:59.000Z

167

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

SciTech Connect

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.

FITZGERALD, ERIC; KOENIG, RICHARD

2005-06-27T23:59:59.000Z

168

Booster Subharmonic RF Capture Design  

NLE Websites -- All DOE Office Websites (Extended Search)

require a < (1 40 ns) 25 MHz subharmonic frequency. Due to the difficulty of building high-voltage low-frequency rf cavities, this requirement can be relaxed so that at least...

169

PARMTEQ (Phase And Radial Motion in Transverse Electric Quadrupole linacs): A beam dynamics code for the RFQ (radio-frequency quadrupole)  

SciTech Connect

The PARMTEQ code is used for generating the complete cell design of a radio-frequency quadrupole linear accelerator and for multiparticle simulation of the beam dynamics. We present a review of the code, with an emphasis on the physics used to describe the particle motion and the cell generation. 9 refs., 1 fig.

Crandall, K.R.; Wangler, T.P.

1987-01-01T23:59:59.000Z

170

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

Science Conference Proceedings (OSTI)

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.

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

2010-01-01T23:59:59.000Z

171

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

DOE Patents (OSTI)

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.

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

1984-01-01T23:59:59.000Z

172

Experimental evaluation of 350 MHz RF accelerator windows for the low energy demonstration accelerator  

SciTech Connect

Radio frequency (RF) windows are historically a point where failure occurs in input power couplers for accelerators. To obtain a reliable, high-power, 350 MHz RF window for the Low Energy Demonstration Accelerator (LEDA) project of the Accelerator Production of Tritium program, RF windows prototypes from different vendors were tested. Experiments were performed to evaluate the RF windows by the vendors to select a window for the LEDA project. The Communications and Power, Inc. (CPI) windows were conditioned to 445 kW in roughly 15 hours. At 445 kW a window failed, and the cause of the failure will be presented. The English Electronic Valve, Inc. (EEV) windows were conditioned to 944 kW in 26 hours and then tested at 944 kW for 4 hours with no indication of problems.

Cummings, K.; Rees, D.; Roybal, W. [and others

1997-09-01T23:59:59.000Z

173

Study of high quality indium nitride films grown on Si(100) substrate by RF-MOMBE with GZO and AlN buffer layers  

Science Conference Proceedings (OSTI)

Wurtzite structure InN films were prepared on Si(100) substrates using radio-frequency metal-organic molecular beam epitaxy (RF-MOMBE) system. Ga-doped ZnO (GZO) and Amorphous AlN (a-AlN) film were used as buffer layers for InN films growth. Structural, ...

Wei-Chun Chen, Shou-Yi Kuo

2012-01-01T23:59:59.000Z

174

Special Presentation: Key Findings from the Barrier Immune Radio  

NLE Websites -- All DOE Office Websites (Extended Search)

Special Presentation: Key Findings from the Barrier Immune Radio Special Presentation: Key Findings from the Barrier Immune Radio Communications Project Speaker(s): Francis Rubinstein Girish Ghatikar Peter Haugen Date: November 29, 2007 - 12:00pm Location: 90-3122 The Barrier Immune Radio Communications (BIRC) Project was established in January 2007 by the Demand Response Emerging Technologies Program (DRETD) to identify radio frequency technologies that could enable the widespread deployment of Demand Response strategies in buildings. Researchers from Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory will present the key findings from this project in a one-hour presentation. Researchers found that several of the RF technologies tested at LBNL's Molecular Foundry building were able to provide sufficiently

175

TheSingleElectronTransistorAsaRadioFrequencyMixer http://www.iquest. ucsb. edu/sites/cleland  

E-Print Network (OSTI)

preamp 0 15 30 0.5 1.0 (pA) 0 CGVS/e (RF) w S=20 MHz Isd CG VG /e n n+1 VDC VRF VRF RF/e) for sinusoidal Ids(VG). Confirmsandcalibrates RFgateaction J0(qRF/e) VRF(S) HomodyneDetection VS(w S) Vsd SET IsdQuantum-limitedMotionDetection I(q)ds CGVG/e n n+1 VDC VRF Gate Charge n-1 VLO VLO VRF (LO) (S) Time I(t)dsI()ds if = |LO-S| LO

Knobel, Robert

176

Experiment for transient effects of sudden catastrophic loss of vacuum on a scaled superconducting radio frequency cryomodule  

SciTech Connect

Safe operation of superconducting radio frequency (SRF) cavities require design consideration of a sudden catastrophic loss of vacuum (SCLV) adjacent with liquid helium (LHe) vessels and subsequent dangers. An experiment is discussed to test the longitudinal effects of SCLV along the beam line of a string of scaled SRF cavities. Each scaled cavity includes one segment of beam tube within a LHe vessel containing 2 K saturated LHe, and a riser pipe connecting the LHe vessel to a common gas header. At the beam tube inlet is a fast acting solenoid valve to simulate SCLV and a high/low range orifice plate flow-meter to measure air influx to the cavity. The gas header exit also has an orifice plate flow-meter to measure helium venting the system at the relief pressure of 0.4 MPa. Each cavity is instrumented with Validyne pressure transducers and Cernox thermometers. The purpose of this experiment is to quantify the time required to spoil the beam vacuum and the effects of transient heat and mass transfer on the helium system. Heat transfer data is expected to reveal a longitudinal effect due to the geometry of the experiment. Details of the experimental design criteria and objectives are presented.

Dalesandro, A.; Theilacker, J.; /Fermilab; Van Sciver, S.W.; /Natl. High Mag. Field Lab.

2011-06-01T23:59:59.000Z

177

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

SciTech Connect

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.

Ohkawa, Tihiro (La Jolla, CA)

1987-01-01T23:59:59.000Z

178

Optical Emission of Dusty RF Discharges: Experiment and Simulation  

Science Conference Proceedings (OSTI)

The spectral emission of argon atoms in a dusty radio frequence (RF) discharge has been investigated experimentally and in simulations. It was observed that the spatially and temporally resolved emission of the argon atoms in the dusty discharge was increased compared to the dust-free case during sheath expansion. The corresponding simulations have revealed that the dust trapped in the sheath of the discharge leads to a small, but important, increase of the amount of high-energy electrons that in turn leads to an increased argon emission.

Melzer, A.; Lewerentz, L.; Schneider, R. [Institute of Physics, University Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Huebner, S. [Institute of Physics, University Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Department of Applied Physics, Technical University Eindhoven, NL-5600 MB Eindhoven (Netherlands); Matyash, K. [Max-Planck-Institute for Plasma Physics, EURATOM Association, D-17491 Greifswald (Germany); Ikkurthi, V. R. [Institute for Plasma Research, Bhat, Ghandinagar, Gujarat (India)

2011-11-29T23:59:59.000Z

179

Radio frequency phototube  

SciTech Connect

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.

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

180

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Modulation instability in RF MEMS devices  

Science Conference Proceedings (OSTI)

Modulation instability generated by mechanical frequencies in RF MEMS switches is predicted and its potential contribution to the RF signal degradation is discussed. In particular, evaluations have been performed for double clamped configurations in ... Keywords: Modulation instability, Nonlinear Schrodinger equation, Power handling, RF MEMS

Romolo Marcelli; Giancarlo Bartolucci; Giorgio Angelis; Andrea Lucibello; Emanuela Proietti

2012-04-01T23:59:59.000Z

182

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

SciTech Connect

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.

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

2009-11-23T23:59:59.000Z

183

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

SciTech Connect

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.

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

2009-03-03T23:59:59.000Z

184

Influence of the Particle Formation and Behavior on the Electrical Parameters in Low Pressure Radio-Frequency CH{sub 4}/N{sub 2} Discharges  

Science Conference Proceedings (OSTI)

The particle formation in low pressure radio-frequency (13.56 MHz) CH{sub 4}/N{sub 2} discharges results from the gas decomposition and from the sputtering of the powered electrode. The particle formation and behavior are strongly modified with the nitrogen amount increase in the mixture. The observation of the particles in the CH{sub 4}/N{sub 2} mixture containing 70% of N{sub 2} reveals a particular particle behavior. The particle behavior is correlated with the electrical parameters of the discharge.

Pereira, J.; Massereau-Guilbaud, V.; Geraud-Grenier, I.; Plain, A. [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G. Berger, BP 4043, 18028 BOURGES CEDEX (France)

2008-03-19T23:59:59.000Z

185

Nitrogen effect on the dust presence and behavior in a radio frequency CH{sub 4}/N{sub 2} discharge  

Science Conference Proceedings (OSTI)

In this paper, we have studied the effects of the nitrogen percentage on particles generated in low pressure radio frequency CH{sub 4}/N{sub 2} discharges. The particle behavior has been analyzed by laser beam extinction and scattering. The nitrogen percentage in the mixture influences the particle presence, behavior, and size in the discharge. For nitrogen percentages greater than 50%, we have evidenced a particle multigeneration and oscillations in particle clouds. These oscillations have been correlated with the discharge electrical parameters.

Pereira, Jeremy; Massereau-Guilbaud, Veronique; Geraud-Grenier, Isabelle; Plain, Andre [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G. Berger, BP 4043, 18028 Bourges Cedex (France)

2008-02-01T23:59:59.000Z

186

High power testing of the 402.5 MHZ and 805 MHZ RF windows for the spallation neutron source accelerator  

SciTech Connect

Hisorically, Radio Frequency (RF) windows have been a common point of failure in input power couplers; therefore, reliable RF windows are critical to the success of the Spallation Neutron Source (SNS) project. The normal conducting part of the SNS accelerator requires six RF windows at 402.5 MHz and eight RF windows at 805 MHz[l]. Each RF window will transmit up to 180 kW of average power and 2.5 MW peak power at 60 Hz with 1.2 millisecond pulses. The RF windows, designed and manufactured by Thales, were tested at the full average power for 4 hours to ensure no problems with the high average power and then tested to an effective forward power level of 10 MW by testing at 2.5 MW forward power into a short and varying the phase of the standing wave. The sliding short was moved from 0 to 180 degrees to ensure no arcing or breakdown problems occur in any part of the window. This paper discusses the results of the high power testing of both the 402.5 MHz and the 805 MHz RF windows. Problems encountered during testing and the solutions for these problems are discussed.

Cummings, K. A. (Karen Ann); De Baca, J. M. (John M.); Harrison, J. S. (John S.); Rodriguez, M. B. (Manuelita B.); Torrez, P. A. (Phillip A.); Warner, D. K. (David K.)

2003-01-01T23:59:59.000Z

187

Eccentric rf deflecting structure  

SciTech Connect

For superconducting rf separators, assembled by electron beam welding techniques, two types of mode stabilizers are discussed: the elliptical structure, and a new design called the eccentric structure''. For an operating pi /2 or pi mode in the lower pass band, it is shown that the various parameters of the eccentric structure can be adjusted to provide the required frequency spacing between the operating mode and the upper dispersion curve. (auth)

Aggus, J.R.; Giordano, S.; Halama, H.J.

1973-12-13T23:59:59.000Z

188

RASDR: Benchtop Demonstration of SDR for Radio Astronomy  

SciTech Connect

The Society of Amateur Radio Astronomers (SARA) members present the benchtop version of RASDR, a Software Defined Radio (SDR) that is optimized for Radio Astronomy. RASDR has the potential to be a common digital receiver interface useful to many SARA members. This document describes the RASDR 0.0 , which provides digitized radio data to a backend computer through a USB 2.0 interface. A primary component of RASDR is the Lime Microsystems Femtocell chip which tunes from a 0.4-4 GHz center frequency with several selectable bandwidths from 0.75 MHz to 14 MHz. A second component is a board with a Complex Programmable Logic Device (CPLD) chip that connects to the Femtocell and provides two USB connections to the backend computer. A third component is an analog balanced mixer up conversion section. Together these three components enable RASDR to tune from 0.015 MHz thru 3.8GHz of the radio frequency (RF) spectrum. We will demonstrate and discuss capabilities of the breadboard system and SARA members will be able to operate the unit hands-on throughout the workshop.

Vacaliuc, Bogdan [ORNL; Oxley, Paul [Retired; Fields, David [ORNL; Kurtz, Dr. Stan [Universidad Nacional Autonoma de Mexico (UNAM); Leech, Marcus [Shirleys Bay Radio Astronomy Consortium

2012-01-01T23:59:59.000Z

189

High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States); Bender, H. A.; Wilcox, N. S. [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

2010-01-15T23:59:59.000Z

190

High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

2010-01-01T23:59:59.000Z

191

RF transformer  

DOE Patents (OSTI)

There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

Smith, James L. (Naperville, IL); Helenberg, Harold W. (Calumet City, IL); Kilsdonk, Dennis J. (Joliet, IL)

1979-01-01T23:59:59.000Z

192

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

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. %.

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

193

Energy fluxes in a radio-frequency magnetron discharge for the deposition of superhard cubic boron nitride coatings  

Science Conference Proceedings (OSTI)

Energy flux measurements by a calorimetric probe in a rf-magnetron plasma used for the deposition of super-hard c-BN coatings are presented and discussed. Argon as working gas is used for sputtering a h-BN target. Adding a certain amount of N{sub 2} is essential for the formation of stoichiometric BN films, since a lack of nitrogen will lead to boron rich films. Subsequently, the contributions of different plasma species, surface reactions, and film growth to the resulting variation of the substrate temperature in dependence on nitrogen admixture are estimated and discussed. In addition, SRIM simulations are performed to estimate the energy influx by sputtered neutral atoms. The influence of magnetron target power and oxygen admixture (for comparison with nitrogen) to the process gas on the total energy flux is determined and discussed qualitatively, too. The results indicate that variation of the energy influx due to additional nitrogen flow, which causes a decrease of electron and ion densities, electron temperature and plasma potential, is negligible, while the admixture of oxygen leads to a drastic increase of the energy influx. The typical hysteresis effect which can be observed during magnetron sputtering in oxygen containing gas mixtures has also been confirmed in the energy influx measurements for the investigated system. However, the underlying mechanism is not understood yet, and will be addressed in further investigations.

Bornholdt, S.; Kersten, H. [Christian-Albrechts-University Kiel, Institute of Experimental and Applied Physics, D-24098 Kiel (Germany); Ye, J.; Ulrich, S. [Karlsruhe Institute of Technology, Institute for Applied Materials-Applied Materials Physics (IAM-AWP), D-76344 Eggenstein-Leopoldshafen (Germany)

2012-12-15T23:59:59.000Z

194

CMOS RF power amplifier design approaches for wireless communications  

E-Print Network (OSTI)

Radio Transmission and Reception (FDD),” Dec. [14] “Marketdivision duplexing (FDD). In TDD, the same frequency band istransmitting and receiving. In FDD, two different frequency

Pornpromlikit, Sataporn

2010-01-01T23:59:59.000Z

195

rf_shield.PDF  

NLE Websites -- All DOE Office Websites (Extended Search)

April 2001 Interaction Region RF Shield Issues G. Stupakov and T.O. Raubenheimer Stanford Linear Accelerator Center Stanford, California 102300 Interaction Region RF Shield...

196

Are Cluster Radio Relics Revived Fossil Radio Cocoons?  

E-Print Network (OSTI)

A new model for the, so called, `cluster radio relics' is presented (Ensslin & Gopal-Krishna 2000). Fossil radio cocoons, resulting from the former activity of radio galaxies, should contain a low energy relativistic electron population and magnetic fields. Electrons with an age of even up to 2 Gyr can be re-accelerated adiabatically to radio emitting energies, if the fossil radio plasma gets compressed in an environmental shock wave. Such a wave can be caused by a merging event of galaxy clusters, or by the accretion onto galaxy clusters. An implication of this model is the existence of a population of diffuse, ultra-steep spectrum, very low-frequency radio sources located inside and possibly outside of clusters of galaxies, tracing the revival of aged fossil radio plasma by the shock waves associated with large-scale structure formation.

Torsten A. Ensslin; Gopal-Krishna

2000-10-30T23:59:59.000Z

197

Low jitter RF distribution system  

SciTech Connect

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.

Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

2012-09-18T23:59:59.000Z

198

Plasma properties of RF magnetron sputtering system using Zn target  

Science Conference Proceedings (OSTI)

In the present work, we investigate the fundamental properties of magnetron sputtering plasma using Zn target and its deposited Zn thin film. The magnetron sputtering plasma was produced using radio frequency (RF) power supply and Argon (Ar) as ambient gas. A Langmuir probe was used to collect the current from the plasma and from the current intensity, we calculate the electron density and electron temperature. The properties of Zn sputtering plasma at various discharge conditions were studied. At the RF power ranging from 20 to 100 W and gas pressure 5 mTorr, we found that the electron temperature was almost unchanged between 2-2.5 eV. On the other hand, the electron temperature increased drastically from 6 Multiplication-Sign 10{sup 9} to 1 Multiplication-Sign 10{sup 10}cm{sup -3} when the discharge gas pressure increased from 5 to 10 mTorr. The electron microscope images show that the grain size of Zn thin film increase when the discharge power is increased. This may be due to the enhancement of plasma density and sputtered Zn density.

Nafarizal, N.; Andreas Albert, A. R.; Sharifah Amirah, A. S.; Salwa, O.; Riyaz Ahmad, M. A. [Microelectronic and Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

2012-06-29T23:59:59.000Z

199

High-Power Rf Load  

DOE Patents (OSTI)

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.

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

1998-09-01T23:59:59.000Z

200

RF/microwave non-destructive measurements of electrical properties of semiconductor wafers for thermophotovoltaic applications  

DOE Green Energy (OSTI)

A radio-frequency/microwave measurement system has been designed for non-contacting determination of sheet resistance and excess carrier lifetime of low-bandgap materials and junctions, specifically GaSb-based alloys for thermophotovoltaic (TPV) applications. The design incorporates RF circuitry in the 100--500 MHz frequency range and utilizes a Q-switched YAG laser at 1.32 microns to photo-generate electron-hole pairs and conductivity modulate the material and/or junction under test. Supplementary measurements with a GaAs pulsed diode laser at 904 nm provides a faster transient response with near-surface photogeneration. Initial measurements on GaSb substrates, Zn-diffused materials and epitaxially grown layers are presented and discussed.

Saroop, S.; Borrego, J.M.; Gutmann, R.J. [Rensselaer Polytechnic Inst., Troy, NY (United States)] [and others

1997-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Theoretical Predictions and Experimental Assessments of the Performance of Alumina RF Windows  

SciTech Connect

Radio frequency (RF) windows are the most likely place for catastrophic failure to occur in input power couplers for particle accelerators. Reliable RF windows are essential for the success of the Accelerator Production of Tritium (APT) program because there are over 1000 windows on the accelerator, and it takes more than one day to recover from a window failure. The goals of this research are to analytically predict the lifetime of the windows, to develop a conditioning procedure, and to evaluate the performance of the RF windows. The analytical goal is to predict the lifetime of the windows. The probability of failure is predicted by the combination of a finite element model of the window, Weibull probabilistic analysis, and fracture mechanics. The window assembly is modeled in a finite element electromagnetic code in order to calculate the electric fields in the window. The geometry (i.e. mesh) and electric fields are input into a translator program to generate the mesh and boundary conditions for a finite element thermal structural code. The temperatures and stresses are determined in the thermal/structural code. The geometry and thermal structural results are input into another translator program to generate an input file for the reliability code. Material, geometry and service data are also input into the reliability code. To obtain accurate Weibull and fatigue data for the analytical model, four point bend tests were done. The analytical model is validated by comparing the measurements to the calculations. The lifetime of the windows is then determined using the reliability code. The analytical model shows the window has a good thermal mechanical design and that fast fracture is unlikely to occur below a power level of 9 Mw. The experimental goal is to develop a conditioning procedure and evaluate the performance of RF windows. During the experimental evaluation, much was learned about processing of the windows to improve the RF performance. Methods of processing included grit blasting and using various coatings.

Karen Ann Cummings

1998-07-01T23:59:59.000Z

202

Rf Feedback free electron laser  

DOE Patents (OSTI)

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.

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

203

Rf feedback free electron laser  

DOE Patents (OSTI)

A free electron laser system and electron beam system for a free electron laser are provided 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.

Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-11-02T23:59:59.000Z

204

Low temperature rf sputtering deposition of (Ba, Sr) TiO{sub 3} thin film with crystallization enhancement by rf power supplied to the substrate  

SciTech Connect

The (Ba, Sr) TiO{sub 3} thin film deposited by radio frequency (rf) sputtering requires a high deposition temperature near 500 deg. C to realize a high relative dielectric constant over of 300. For example, the film deposited at 330 deg. C contains an amorphous phase and shows a low relative dielectric constant of less than 100. We found that rf power supplied not only to the (Ba, Sr) TiO{sub 3} sputtering target, but also to the substrate during the initial step of film deposition, enhanced the crystallization of the (Ba, Sr) TiO{sub 3} film drastically and realized a high dielectric constant of the film even at low deposition temperatures near 300 deg. C. The 50-nm-thick film with only a 10 nm initial layer deposited with the substrate rf biasing is crystallized completely and shows a high relative dielectric constant of 380 at the deposition temperature of 330 deg. C. The (Ba, Sr) TiO{sub 3} film deposited at higher temperatures (upwards of 400 deg. C) shows <110> preferred orientation, while the film deposited at 330 deg. C with the 10 nm initial layer shows a <111> preferred orientation on a <001>-oriented ruthenium electrode. The unit cell of (Ba, Sr) TiO{sub 3} (111) plane is similar to that of ruthenium (001) plane. We conclude that the rf power supplied to the substrate causes ion bombardments on the (Ba, Sr) TiO{sub 3} film surface, which assists the quasiepitaxial growth of (Ba, Sr) TiO{sub 3} film on the ruthenium electrode at low temperatures of less than 400 deg. C.

Yoshimaru, Masaki; Takehiro, Shinobu; Abe, Kazuhide; Onoda, Hiroshi [System LSI Research Division, Silicon Solution Company, Oki Electric Industry Co., Ltd., 550-1, Higashi-asakawa, Hachioji, Tokyo 193-8550 (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Strategic Planning Office, Silicon Manufacturing Company, Oki Electric Industry Co., Ltd., 550-1, Higashi-asakawa, Hachioji, Tokyo 193-8550 (Japan)

2005-05-01T23:59:59.000Z

205

Impulse Radio Ultra-Wideband Communication Over Free-Space Optical Links  

E-Print Network (OSTI)

A composite impulse radio ultra-wideband (IR-UWB) communication system is presented. The proposed system model aims to transmit UWB pulses over several kilometers through free-space optical (FSO) links and depending on the link design, the electrical estimates of the FSO system can be directly used or distributed to end-user through radio-frequency (RF) links over short ranges. However, inhomogeneities on the FSO transmission path cause random fluctuations in the received signal intensity and these effects induced by atmospheric turbulence closely effect the system performance. Several distinct probability distributions based on experimental measurements are used to characterize FSO channels and using these probabilistic models, detection error probability analysis of the proposed system for different link designs are carried out under weak, moderate and strong turbulence conditions. The results of the analysis show that depending on the atmospheric conditions, system performance of the composite link can hav...

Davaslioglu, Kemal

2013-01-01T23:59:59.000Z

206

Radiolysis with RF Photoinjectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiolysis with RF Photoinjectors: Supercritical Xenon Chemistry James F. Wishart in "Femtosecond Beam Science" Uesaka, M., Ed.; Imperial College Press, London, in press. (ISBN...

207

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

E-Print Network (OSTI)

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 ...

Karpe, Charvak (Charvak P.)

2006-01-01T23:59:59.000Z

208

RF cavity using liquid dielectric for tuning and cooling  

SciTech Connect

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.

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

2012-04-17T23:59:59.000Z

209

Prospects for Advanced RF Theory and Modeling  

SciTech Connect

This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed.

Batchelor, D.B.

1999-04-12T23:59:59.000Z

210

Dual-etalon, cavity-ring-down, frequency comb spectroscopy.  

Science Conference Proceedings (OSTI)

The 'dual etalon frequency comb spectrometer' is a novel low cost spectometer with limited moving parts. A broad band light source (pulsed laser, LED, lamp ...) is split into two beam paths. One travels through an etalon and a sample gas, while the second arm is just an etalon cavity, and the two beams are recombined onto a single detector. If the free spectral ranges (FSR) of the two cavities are not identical, the intensity pattern at the detector with consist of a series of heterodyne frequencies. Each mode out of the sample arm etalon with have a unique frequency in RF (radio-frequency) range, where modern electronics can easily record the signals. By monitoring these RF beat frequencies we can then determine when an optical frequencies is absorbed. The resolution is set by the FSR of the cavity, typically 10 MHz, with a bandwidth up to 100s of cm{sup -1}. In this report, the new spectrometer is described in detail and demonstration experiments on Iodine absorption are carried out. Further we discuss powerful potential next generation steps to developing this into a point sensor for monitoring combustion by-products, environmental pollutants, and warfare agents.

Strecker, Kevin E.; Chandler, David W.

2010-10-01T23:59:59.000Z

211

Computational strategy for modeling radio wave propagation in lossy circular waveguides  

SciTech Connect

The propagation of radio waves in lossy waveguides and tunnels has been researched extensively for many years as can be seen in the detailed book by Wait. The mathematics used to model waveguides for communications is essentially the same as that needed to model radio frequency (RF) propagation in simple tunnels. The presence or lack of conductors inside a waveguide or tunnel is a key driver in the nature of the solutions one will find for a particular application, Delogne. When there are conductors passing through a waveguide or tunnel, the simplest modes of propagation are surface-guided waves following the conductor and typically enabling long-range transmission. A tunnel containing a core conductor can act rather like a coaxial cable, propagating waves at a nearly constant speed, regardless of frequency. Conversely, a tunnel or waveguide without internal conductors is subject to very different wave patterns, resulting in a much more complex propagation analysis. Holloway et al. presented an exhaustive study of RF propagation in circular structures embedded in lossy surroundings. The work of Holloway et al. is the basis for this paper, where we discuss application of their computational techniques and present refinements gleaned from our work on similar problems.

Moses, Ronald [Los Alamos National Laboratory; Cai, D Michael [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

212

Production of higher silanes in radio frequency SiH{sub 4} and H{sub 2}-SiH{sub 4} plasmas  

SciTech Connect

Stable gases produced in SiH{sub 4} and H{sub 2}-SiH{sub 4}, capacitively coupled rf discharges operated at typical device-production conditions, were investigated by quadrupole mass spectrometry. The production of disilane and trisilane and the depletion of silane and pressure change were measured during consecutive short discharges. Dissociation rate constants and branching ratios for higher-silane production are obtained from the time-dependent densities. The influence of suspended Si particles on stable-gas production is found to be negligible, by changing the duration of individual discharges and thereby the particle densities and sizes. We have also observed pyrolitic decay of disilane and trisilane at 200 deg. C, although this is negligible under normal reactor conditions.

Horvath, P.; Rozsa, K.; Gallagher, A. [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309-0440 (United States)

2004-12-15T23:59:59.000Z

213

1814 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 44, NO. 6, JUNE 2009 A Bio-Inspired Active Radio-Frequency  

E-Print Network (OSTI)

: analysis time, power and hardware usage all scale linearly with , the number of output frequency bins cochlea designs with sharper rolloff slopes and lower group delay than prior all-pole versions. Index with position: The membrane gradually becomes wider and less stiff, and resonates at lower frequencies. Thus

Sarpeshkar, Rahul

214

Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation  

Science Conference Proceedings (OSTI)

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.

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

2011-03-28T23:59:59.000Z

215

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

SciTech Connect

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.

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

2008-01-01T23:59:59.000Z

216

High quality ultrathin Bi{sub 2}Se{sub 3} films on CaF{sub 2} and CaF{sub 2}/Si by molecular beam epitaxy with a radio frequency cracker cell  

Science Conference Proceedings (OSTI)

We report a method to fabricate high quality Bi{sub 2}Se{sub 3} thin films using molecular beam epitaxy with a radio frequency cracker cell as an atomic selenium source. With Se-to-Bi ratios close to exact stoichiometry, optimal layer-by-layer growth of high quality Bi{sub 2}Se{sub 3} thin films with smooth surfaces has been achieved on CaF{sub 2}(111) substrates and Si(111) substrates with a thin epitaxial CaF{sub 2} buffer layer (CaF{sub 2}/Si). Transport measurements show a characteristic weak-antilocalization magnetoresistance in all the films, with the emergence of a weak-localization contribution in the ultrathin film limit. Quantum oscillations, attributed to the topological surface states have been observed, including in films grown on CaF{sub 2}/Si.

Zhang Li; Dolev, Merav [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Hammond, Robert [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Liu Min [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); Palevski, Alexander [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Kapitulnik, Aharon [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States)

2012-10-08T23:59:59.000Z

217

Populations of metastable and resonant argon atoms in radio frequency magnetron plasmas used for deposition of indium-zinc-oxide films  

Science Conference Proceedings (OSTI)

This work reports optical absorption spectroscopy measurements of the number density of Ar atoms in resonant ({sup 3}P{sub 1}, {sup 1}P{sub 1}) and metastable ({sup 3}P{sub 2}, {sup 3}P{sub 0}) states in rf magnetron sputtering plasmas used for the deposition of ZnO-based thin films. While the density of Ar {sup 3}P{sub 2} and {sup 3}P{sub 0} was fairly independent of pressure in the range of experimental conditions investigated, the density of Ar {sup 3}P{sub 1} and {sup 1}P{sub 1} first sharply increased with pressure and then reached a plateau at values close to those of the {sup 3}P{sub 2} and {sup 3}P{sub 0} levels at pressures above about 50 mTorr. At such pressures, ultraviolet radiation from resonant states becomes trapped such that these levels behave as metastable states. For a self-bias voltage of -115 V and pressures in the 5-100 mTorr range, similar number densities of Ar resonant and metastable atoms were obtained for Zn, ZnO, and In{sub 2}O{sub 3} targets, suggesting that, over the range of experimental conditions investigated, collisions between these excited species and sputtered Zn, In, and O atoms played only a minor role on the discharge kinetics. The metastable-to-ground state number density ratios were also fitted to the predictions of a global model using the average electron temperature, T{sub e}, as the only adjustable parameter. For all targets examined, the values of T{sub e} deduced from this method were in excellent agreement with those obtained from Langmuir probe measurements.

Maaloul, L.; Morel, S.; Stafford, L. [Departement de Physique, Universite de Montreal, Montreal, Quebec, H3C 3J7 (Canada)

2012-03-15T23:59:59.000Z

218

ISG8-RF Sources  

NLE Websites -- All DOE Office Websites (Extended Search)

RF Sources - (WG3) RF Sources - (WG3) Orange Rm Yong Ho Chin, Christopher Nantista, and Sami G. Tantawi Parallel Sessions: Working Groups: WG1: Parameters, Design, Instrumentation and Tuning WG2: Damping Rings and ATF WG3: RF Sources WG4:Structures WG5: Ground Motion; Site Requirements and Investigations Monday Morning 9:00-10:30 Plenary Coffee Break 11:00-12:00 Planning Session. Monday Afternoon 13:30-15:30 High Gradient Issues (Joint with working group 4) Coffee Break 16:00-16:30 The 8-Pack Project -- D. Atkinson 16:30-17:30 High Gradient Issues and Discussions Continued. Tuesday Morning 9:30-10:30 Klystrons 9:30-10:00 Status of PPM Klystron Development for JLC -- Y. H. Chin 10:00-10:30 Design of 150MW Multi-Beam Klystron -- S. Matsumoto Coffee Break 11:00-11:30 Klystron Development at SLAC -- G. Caryotakis

219

Rf2a and rf2b transcription factors  

DOE Patents (OSTI)

A method of activating the rice tungro bacilliform virus (RTBV) promoter in vivo is disclosed. The RTBV promoter is activated by exposure to at least one protein selected from the group consisting of Rf2a and Rf2b.

Beachy, Roger N. (St. Louis, MO); Petruccelli, Silvana (La Plata, AR); Dai, Shunhong (St. Louis, MO)

2007-10-02T23:59:59.000Z

220

The environments of radio-loud quasars  

E-Print Network (OSTI)

We have obtained multi-colour imaging of a representative, statistically complete sample of low-frequency selected (S_408MHz > 0.95Jy) radio loud quasars at intermediate (0.6 environmental richness, based upon single-band observations are inadequate at these redshifts for a variety of reasons. Environmental richness seems correlated with the size and morphology of the radio source, as expected if the energy density in the radio lobes is approximately the equipartition value and the lobes are in pressure equilbrium with a surrounding intragroup/cluster medium. Selecting on radio size therefore efficiently selects dense galactic sytems at these redshifts.

J. M. Barr; M. N. Bremer; J. C. Baker

2001-04-18T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Development of a CW Superconducting RF Booster Cryomodule for Future Light Sources  

Science Conference Proceedings (OSTI)

Future light sources based on seeded free electron lasers (FEL) have the potential to increase the soft xray flux by several orders of magnitude with short bunch lengths to probe electron structure and dynamics. A low emittance, high rep-rate radio frequency (RF) photocathode electron gun will generate the electron beam that will require very stringent beam control and manipulation through the superconducting linear accelerator to maintain the high brightness required for an x-ray FEL. The initial or booster cavities of the superconducting radio frequency (SRF) linear accelerator will require stringent control of transverse kicks and higher order modes (HOM) during the beam manipulation and conditioning that is needed for emittance exchange and bunch compression. This SBIR proposal will develop, fabricate and test a continuous-wave SRF booster cryomodule specifically for this application. Phase I demonstrated the technical feasibility of the project by completing the preliminary SRF cavity and cryomodule design and its integration into an R&D test stand for beam studies at Lawrence Berkeley National Laboratory (LBNL). The five-cell bulk niobium cavities operate at 750 MHz, and generate 10 MV each with strong HOM damping and special care to eliminate transverse kicks due to couplers. Due to continuous-wave operation at fairly modest beam currents and accelerating gradients the complexity of the two cavity cryomodule is greatly reduced compared to an ILC type system. Phase II will finalize the design, and fabricate and test the booster cryomodule. The cryomodule consists of two five-cell cavities that will accelerate megahertz bunch trains with nano-coulomb charge. The accelerating gradient is a very modest 10 MV/m with peak surface fields of 20 MV/m and 42.6 mT. The cryogenic system operates at 2 K with a design dynamic load of 20 W and total required cryogenic capacity of 45 W. The average beam current of up to 1 mA corresponds to a beam power of 10 kW per 5- cell cavity and will require 20 kW of RF power for transmission, control and regulation. The RF power will be supplied by a commercial tetrode. Cryogenic tests will be carried out at LBNL to make use of their test facilities, cryogenics and laser systems, and for future use with beam. Demonstration of this new type of booster cryomodule will open many new applications of SRF linear accelerators.

Grimm, Terry L; Bogle, Andrew; Deimling, Brian; Hollister, Jerry; II, Randall Jecks; Kolka, Ahren; Romel, Chandra

2009-04-13T23:59:59.000Z

222

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

SciTech Connect

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.

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

2012-03-01T23:59:59.000Z

223

Rf heating of mirrors  

SciTech Connect

A brief overview is presented of potential uses for rf heating of plasmas in mirror devices. While some discussion relating to past experiments is given, the main emphasis is devoted to a review of potential experiments in presently existing devices, and devices under construction or planning. Some predictions are made for plasmas in mirror reactors.

Porkolab, M.

1980-04-09T23:59:59.000Z

224

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

SciTech Connect

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.

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

2007-01-01T23:59:59.000Z

225

Robust Low-Frequency Spread-Spectrum Navigation System ...  

•Military, emergency, and law-enforcement safety applications •Radio-frequency communications, wireless security, and intermodal logistics

226

radioCherenkov.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

. . Coherent radio Cherenkov radiation detectors: Revised February 2013 by S.R. Klein (LBNL/UC Berkeley) 100 10 10 -4 10 -3 10 -5 1.0 0.1 0.01 E 2 I(E ν ) [GeV m -2 s -1 sr -1 ] E ν [GeV] ν NuMoon 10 9 10 10 10 11 10 12 10 13 10 14 10 15 ATCA (no SSR) ATCA (SSR incl.) RICE ANITA Central GZK ν flux predictions Central GZK ν flux predictions Figure 1: Representative ν flux limits from radio-detection experiments, illustrating the energy ranges for different techniques. Shown are limits from the Rice, ANITA, NuMoon and Lunaska (ATCA) collaborations. NuMoon and Lunaska are low and high frequency lunar scans respectively, showing the strengths of the two different frequency bands. The two limits for ATCA are for different models of the lunar regolith; their separation is a measure of the resultant uncertainty. Also shown, for comparison is the mid-range of flux predictions

227

Auction-Based Throughput Maximization in Cognitive Radio Networks Under Interference Constraint  

Science Conference Proceedings (OSTI)

Cognitive radio is an emerging technique to improve the utilization of radio frequency spectrum in wireless communication networks. That is, spectrum efficiency can be increased significantly by giving opportunistic access of the frequency bands to a ... Keywords: Auction, Channel assignment, Cognitive radio, Graph theory, Interference constraint, OSI cross layer applications

Hakan Murat Karaca, Tolga Kurt, Salih Zafer Dicle, Emin Anarim

2013-09-01T23:59:59.000Z

228

RF current sensor  

DOE Patents (OSTI)

An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Moore, James A. (Powell, TN); Sparks, Dennis O. (Maryville, TN)

1998-11-10T23:59:59.000Z

229

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

E-Print Network (OSTI)

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

Stancil, Daniel D.

230

Technical Note: Suppression of artifacts arising from simultaneous cone-beam imaging and RF transponder tracking in prostate radiotherapy  

SciTech Connect

Purpose: Artifacts in treatment-room cone-beam reconstructions have been observed at the authors' center when cone-beam acquisition is simultaneous with radio frequency (RF) transponder tracking using the Calypso 4D system (Calypso Medical, Seattle, WA). These artifacts manifest as CT-number modulations and increased CT-noise. The authors present a method for the suppression of the artifacts. Methods: The authors propose a three-stage postprocessing technique that can be applied to image volumes previously reconstructed by a cone-beam system. The stages are (1) segmentation of voxels into air, soft-tissue, and bone; (2) application of a 2D spatial-filter in the axial plane to the soft-tissue voxels; and (3) normalization to remove streaking along the axial-direction. The algorithm was tested on patient data acquired with Synergy XVI cone-beam CT systems (Elekta, Crawley, United Kingdom). Results: The computational demands of the suggested correction are small, taking less than 15 s per cone-beam reconstruction on a desktop PC. For a moderate loss of spatial-resolution, the artifacts are strongly suppressed and low-contrast visibility is improved. Conclusions: The correction technique proposed is fast and effective in removing the artifacts caused by simultaneous cone-beam imaging and RF-transponder tracking.

Poludniowski, Gavin; Webb, Steve; Evans, Philip M. [Joint Department of Physics, Division of Radiotherapy and Imaging, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey, SM2 5PT (United Kingdom)

2012-03-15T23:59:59.000Z

231

High-efficiency Resonant rf Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams  

SciTech Connect

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPD Gamma experiment, a search for the small parity-violating {gamma}-ray asymmetry A{sub Y} in polarized cold neutron capture on parahydrogen, is one example. For the NPD Gamma experiment we 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. 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 {sup 3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8 {+-} 0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPD Gamma experiment are considered.

Seo, P. -N. [Los Alamos National Laboratory (LANL); Barron-Palos, L. [Arizona State University; Bowman, J. D. [Los Alamos National Laboratory (LANL); Chupp, T. E. [University of Michigan; Crawford, C. [University of Tennessee, Knoxville (UTK); Dabaghyan, M. [University of New Hampshire; Dawkins, M. [Indiana University; Freedman, S. J. [University of California; Gentile, T. R. [National Institute of Standards and Technology (NIST); Gericke, M. T. [University of Manitoba, Canada; Gillis, R. C. [University of Manitoba, Canada; Greene, G. L. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Hersman, F. W. [University of New Hampshire; Jones, G. L. [Hamilton College, New York; Kandes, M. [University of Michigan; Lamoreaux, S. [Los Alamos National Laboratory (LANL); Lauss, B. [University of California, Berkeley; Leuschner, M. B. [Indiana University; Mahurin, R. [University of Tennessee, Knoxville (UTK); Mason, M. [University of New Hampshire; Mei, J. [Indiana University; Mitchell, G. S. [Los Alamos National Laboratory (LANL); Nann, H. [Indiana University; Page, S. A. [University of Manitoba, Canada; Penttila, S. I. [Los Alamos National Laboratory (LANL); Ramsay, W. D. [University of Manitoba & TRIUMF, Canada; Salas Bacci, A. [Los Alamos National Laboratory (LANL); Santra, S. [Indiana University; Sharma, M. [University of Michigan; Smith, T. B. [University of Dayton, Ohio; Snow, W. [Indiana University; Wilburn, W. S. [Los Alamos National Laboratory (LANL); Zhu, H. [University of New Hampshire

2008-01-01T23:59:59.000Z

232

High power RF test of an 805 MHz RF cavity for a muon cooling channel  

SciTech Connect

We present recent high power RF test results on an 805 MHz cavity for a muon cooling experiment at Lab G in Fermilab. In order to achieve high accelerating gradient for large transverse emittance muon beams, the cavity design has adopted a pillbox like shape with 16 cm diameter beam iris covered by thin Be windows, which are demountable to allow for RF tests of different windows. The cavity body is made from copper with stiff stainless steel rings brazed to the cavity body for window attachments. View ports and RF probes are available for visual inspections of the surface of windows and cavity and measurement of the field gradient. Maximum of three thermo-couples can be attached to the windows for monitoring the temperature gradient on the windows caused by RF heating. The cavity was measured to have Q{sub 0} of about 15,000 with copper windows and coupling constant of 1.3 before final assembling. A 12 MW peak power klystron is available at Lab G in Fermilab for the high power test. The cavity and coupler designs were performed using the MAFIA code in the frequency and the time domain. Numerical simulation results and cold test measurements on the cavity and coupler will be presented for comparisons.

Li, Derun; Corlett, J.; MacGill, R.; Rimmer, R.; Wallig, J.; Zisman, M.; Moretti, A.; Qian, Z.; Wu, V.; Summers, D.; Norem, J.

2002-05-30T23:59:59.000Z

233

Recent advances in RF power generation  

SciTech Connect

This paper is a review of the progress and methods used in RF generation for particle accelerators. The frequencies of interest are from a few megahertz to 100 GHz, and the powers are for super linear collider applications, but in this case the pulses are short, generally below 1 {mu}s. The very high-power, short-pulse generators are only lightly reviewed here, and for more details the reader should follow the specialized references. Different RF generators excel over various parts of the frequency spectrum. Below 100 MHz solid-state devices and gridded tubes prevail, while the region between 400 MHz and 3 GHz, the cyclotron-resonant devices predominate, and above 250 GHz, Free-Electron Lasers and ubitrons are the most powerful generators. The emphasis for this review is on microwave generation at frequencies below 20 GHz, so the cyclotron-resonant devices are only partially reviewed, while the progress on free-electron laser and ubitrons is not reviewed in this paper. 39 refs., 4 figs.

Tallerico, P.J.

1990-01-01T23:59:59.000Z

234

Radio-Frequency Electronics Group Homepage  

Science Conference Proceedings (OSTI)

... High Speed Electronics—This project supports the microwave, telecommunications ... this project we measure the fundamental electrical ...

2010-12-22T23:59:59.000Z

235

Radio frequency digital to analog converter  

E-Print Network (OSTI)

Dynamic performance of high speed, high resolution digital-to-analog converters (DACs) is limited by distortion at the data switching instants. Inter-symbol interference (ISI), imperfect timing synchronization and clock ...

Luschas, Susan, 1975-

2003-01-01T23:59:59.000Z

236

Overview of Personal Radio Frequency Communication Technologies  

Science Conference Proceedings (OSTI)

Personal wireless communication devices seem to be everywhere. Cell phones, Blackberries, Wi-Fi Internet connections and many other similar devices are in constant use, often simultaneously by a single person. As the proliferation of wireless products expands, their ubiquity raises questions concerning their effects on each other and the people who use them. The effects of one communications device on another one nearby fall under the category of electromagnetic compatibility. Compatibility issues arise ...

2009-07-17T23:59:59.000Z

237

Light modulated switches and radio frequency emitters  

DOE Patents (OSTI)

The disclosure relates to a light modulated electron beam driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

Wilson, Mahlon T. (Los Alamos, NM); Tallerico, Paul J. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

238

Radio Frequency Identification Tags - Passive Tags ...  

Computers & Electronics; Consumer Products; Energy & Utilities; Entertainment & Recreation; Fabric & Apparel; Food, Beverage & ...

239

Phase manipulation for efficient radio frequency transmission  

E-Print Network (OSTI)

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 ...

Barton, Taylor Wallis

2012-01-01T23:59:59.000Z

240

NSLS-II RF SYSTEMS  

Science Conference Proceedings (OSTI)

The NSLS-II is a new third generation light source being constructed at Brookhaven Lab. The storage ring is optimized for low emittance by use of damping wigglers to reduce the emittance to below 1 nm-rad. The RF systems are designed to provide stable beam through tight RF phase and amplitude stability requirements.

Rose, J.; Gash, W.; Holub, B.; Kawashima, Y.; Ma, H.; Towne, N.; Yeddulla, M.

2011-03-28T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

MSTC - Microsystems Science, Technology, and Components - RF...  

NLE Websites -- All DOE Office Websites (Extended Search)

capability for the unique demands of National Security. Communications RF MEMS Passive wireless sensorsRFIDsTags RF system minaturization For additional information or...

242

Microsoft PowerPoint - rf_5year_review  

NLE Websites -- All DOE Office Websites (Extended Search)

RF Research Program RF Research Program DOE Review of C-Mod Five-Year Proposal May 13-14, 2003 MIT PSFC Presented by Steve J.Wukitch Outline: 1. Overview of the RF Program 2. Five-year plan Overview of the RF Program AT: validate steady state operation with target parameters β N = 3, I non = 100%, I BS ~ 70%, H 89 ~ 2.5, for t pulse > t L/R . BPX: demonstrate the viability of high performance plasmas, B T = 8T, I p = 2 MA, P = 6 MW, H 89 ≥ 2, Z eff < 1.5. B T = 5.4T, I p = 1.4 MA, P = 6 MW, H 89 = 2 (ITER demo) Exclusively use RF power for auxiliary heating and current drive. variable variable fixed Phase 2 x 4 Strap 4 Strap 2 x 2 Strap Antenna 4 MW 40-80 MHz J-port 2 x 4 MW 2 x 2 MW Power 40-80 MHz ~ 80 MHz Frequency E & J-port D & E-port 2005-2008 2002-2005 4.6 GHz 4.6 GHz Frequency 16 x 250 kW

243

A 12 GHz RF Power Source for the CLIC Study  

SciTech Connect

The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for CLIC accelerating structure testing. A design and fabrication contract for five klystrons at that frequency has been signed by different parties with SLAC. France (IRFU, CEA Saclay) is contributing a solid state modulator purchased in industry and specific 12 GHz RF network components to the CLIC study. RF pulses over 120 MW peak at 230 ns length will be obtained by using a novel SLED-I type pulse compression scheme designed and fabricated by IAP, Nizhny Novgorod, Russia. The X-band power test stand is being installed in the CLIC Test Facility CTF3 for independent structure and component testing in a bunker, but allowing, in a later stage, for powering RF components in the CTF3 beam lines. The design of the facility, results from commissioning of the RF power source and the expected performance of the Test Facility are reported.

Schirm, Karl; /CERN; Curt, Stephane; /CERN; Dobert, Steffen; /CERN; McMonagle, Gerard; /CERN; Rossat, Ghislain; /CERN; Syratchev, Igor; /CERN; Timeo, Luca; /CERN; Haase, Andrew /SLAC; Jensen, Aaron; /SLAC; Jongewaard, Erik; /SLAC; Nantista, Christopher; /SLAC; Sprehn, Daryl; /SLAC; Vlieks, Arnold; /SLAC; Hamdi, Abdallah; /Saclay; Peauger, Franck; /Saclay; Kuzikov, Sergey; /Nizhnii Novgorod, IAP; Vikharev, Alexandr; /Nizhnii Novgorod, IAP

2012-07-03T23:59:59.000Z

244

Radio Channel Simulator  

Radio Channel Simulator (RCSim) is a simulation package for making site-specific predictions of radio signal strength. The software computes received power atdiscrete grid points as a function of the transmitter location and propagation environment. ...

245

Spectroscopy of {sup 257}Rf.  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {micro}s, was discovered by detecting internal conversion electrons followed by decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF} = 0.02 {+-} 0.01.

Qian, J.; Heinz, A.; Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Asai, M.; Back, B. B.; Carpenter, M. P.; Garnsworthy, A. B.; Greene, J. P.; Hecht, A. A.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X.; Winkler, R.; Zhu, S.; Yale Univ.; Japan Atomic Energy Agency; Univ. of Surrey; Univ. of Maryland

2009-06-01T23:59:59.000Z

246

Spectroscopy of {sup 257}Rf  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on {alpha} hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by {alpha} decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF}=0.02{+-}0.01.

Qian, J.; Heinz, A.; Winkler, R. [WNSL, Yale University, New Haven, Connecticut 06511 (United States); Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X. [Argonne National Laboratory, Illinois 60439 (United States)] (and others)

2009-06-15T23:59:59.000Z

247

Effect of O{sub 2} gas partial pressure on mechanical properties of Al{sub 2}O{sub 3} films deposited by inductively coupled plasma-assisted radio frequency magnetron sputtering  

SciTech Connect

The effect of O{sub 2} partial pressure on the mechanical properties of Al{sub 2}O{sub 3} films is studied. Using films prepared by inductively coupled plasma-assisted radio frequency magnetron sputtering, the deposition rate of Al{sub 2}O{sub 3} decreases rapidly when oxygen is added to the argon sputtering gas. The internal stresses in the films are compressive, with magnitude decreasing steeply from 1.6 GPa for films sputtered in pure argon gas to 0.5 GPa for films sputtered in argon gas at an O{sub 2} partial pressure of 0.89 Multiplication-Sign 10{sup -2} Pa. Stress increases gradually with increasing O{sub 2} partial pressure. Using a nanoindentation tester with a Berkovich indenter, film hardness was measured to be about 14 GPa for films sputtered in pure argon gas. Hardness decreases rapidly on the addition of O{sub 2} gas, but increases when the O{sub 2} partial pressure is increased. Adhesion, measured using a Vickers microhardness tester, increases with increasing O{sub 2} partial pressure. Electron probe microanalyzer measurements reveal that the argon content of films decreases with increasing O{sub 2} partial pressure, whereas the O to Al composition ratio increases from 1.15 for films sputtered in pure argon gas to 1.5 for films sputtered in argon gas at O{sub 2} partial pressures over 2.4 Multiplication-Sign 10{sup -2} Pa. X-ray diffraction measurements reveal that films sputtered in pure argon gas have an amorphous crystal structure, whereas {gamma}-Al{sub 2}O{sub 3} is produced for films sputtered in argon gas with added O{sub 2} gas. Atomic force microscopy observations reveal that the surface topography of sputtered Al{sub 2}O{sub 3} films changes from spherical to needlelike as O{sub 2} partial pressure is increased. Fracture cross sections of the films observed by scanning electron microscopy reveal that the film morphology exhibits no discernible features at all O{sub 2} partial pressures.

Fujiyama, Hirokazu; Sumomogi, Tsunetaka; Nakamura, Masayoshi [Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajirohigashi, Higashi-ku, Fukuoka 811-0295 (Japan); Faculty of Engineering, Hiroshima Kokusai Gakuin University, 6-20-1 Nakano, Aki-ku, Hiroshima 739-0321 (Japan)

2012-09-15T23:59:59.000Z

248

Pushing the Limits of RF Superconductivity Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Presentations Workshop Proceedings Suggested Reading Material on RF Superconductivity Workshop Dinner Accommodations Ground Transportation Access to...

249

RF Breakdown Studies Using a 1.3 GHZ Test Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R.P.; Neubauer, M.; /Muons Inc., Batavia; Conde, M.; Gai, W.; /Argonne; Moretti, A.; Popovic, M.; Yonehara, K.; /Fermilab; Byrd, J.; Li, D.; /LBL, Berkeley; BastaniNejad, M.; /Old Dominion U.

2009-05-01T23:59:59.000Z

250

RF Breakdown Studies Using a 1.3-GHz Text Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R. P.; Neubauer, M.; Conde, M.; Gai, W.; Moretti, A.; Popovic, M.; Yonehara, K.; Byrd, J.; Li, D.; BastaniNejad, M.; Elmustafa, M.

2009-05-04T23:59:59.000Z

251

Growth of TiO{sub 2} Thin Film on Various Substrates using RF Magnetron Sputtering  

Science Conference Proceedings (OSTI)

The conductivity of Titanium Dioxide (TiO{sub 2}) thin film fabricated using Radio Frequency (RF) Magnetron Sputtering on Silicon (Si), Indium doped--Tin Oxide (ITO) and microscope glass (M) substrates is presented in this paper. The dependant of thin film thickness and type of substrate been discussed. TiO{sub 2} was deposited using Ti target in Ar+O{sub 2}(45:10) mixture at 250 W for 45, 60, 75, 90, 105 and 120 minute. Resultant thickness varies from 295 nm to 724 nm with deposition rate 6.4 nm/min. On the other hand, resistivity, Rs value for ITO substrate is between 5.72x10{sup -7} to 1.54x10{sup -6{Omega}}.m, Si substrate range is between 3.52x10{sup -6} to 1.76x10{sup -5{Omega}}.m and M substrate range is between 99 to 332 {Omega}.m. The value of resistivity increases with the thickness of the thin film.

Ali, Riyaz Ahmad Mohamed; Nayan, Nafarizal [Microelectronic and Nanotechnology-Shamsuddin Research Center (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Batu Pahat, Johor D.T. (Malaysia)

2011-03-30T23:59:59.000Z

252

RF-Plasma Source Commissioning in Indian Negative Ion Facility  

Science Conference Proceedings (OSTI)

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.

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

253

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

NLE Websites -- All DOE Office Websites (Extended Search)

Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide...

254

EIA Radio test  

U.S. Energy Information Administration (EIA) Indexed Site

September 10, 2012 September 10, 2012 Test of Energy News Radio Service This is a test audio file of the U.S. Energy Information Administration's energy news radio service to be launched on Tuesday, September 11 th with the release of EIA's monthly Short-Term Energy Outlook. EIA's radio service will provide free short broadcast stories on EIA energy data reports and analysis to radio stations nationwide. The stories will be recorded in MP3 format and can be downloaded from EIA's radio service webpage at www.eia.gov/radio. The first broadcast stories will be posted around noon Eastern Time on Sept. 11 after the release of EIA's monthly Short Term Energy Outlook forecast. These initial stories will focus on the outlook for U.S. gasoline prices, crude oil production and natural gas production.

255

Underground radio technology saves miners and emergency response personnel  

NLE Websites -- All DOE Office Websites (Extended Search)

Underground radio technology saves miners and emergency response Underground radio technology saves miners and emergency response personnel Underground radio technology saves miners and emergency response personnel Founded through LANL, Vital Alert Technologies, Inc. (Vital Alert) has launched a wireless, two-way real-time voice communication system that is effective through 1,000+ feet of solid rock. April 3, 2012 Vital Alert's C1000 mine 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 links through rock strata and other solid media. Vital Alert's C1000 mine 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 links through rock

256

An Efficient Supply Modulator for Linear Wideband RF Power Amplifiers  

E-Print Network (OSTI)

Radio Frequency (RF) Power Amplifiers are responsible for a considerable amount of the power consumption in the entire transmitter-receiver (transceiver) of modern communication systems. The stringent linearity requirements of multi-standard transceivers to minimize cross-talking effects makes Linear Power Amplifiers, particularly class A, the preferred choice in broadband transceivers. This linearity requirement coupled with the fact that the Power Amplifier operates at low transmit power during most of its operation makes the efficiency of the entire transceiver poor. The limited transceiver efficiency leads to a reduction in the battery life of battery operated portable devices like mobile phones; hence drastically limiting talk time. To alleviate this issue, several research groups propose solutions to improve PA power efficiency. However, these solutions usually have a low efficiency at low power and are mostly limited to narrow bandwidth applications. In this thesis, the efficiency of a class A Power amplifier in wideband wireless standards like WiMax is improved by dynamically controlling the bias current and supply voltage of the PA. An efficient supply modulator based on a switching regulator architecture is proposed for controlling the supply voltage. The switching regulator is found to be slew-limited by the bulky inductor and capacitor used to regulate the supply voltage. The proposed solution alleviates the slew rate limitation by adding a bang-bang controlled current source. The proposed supply modulator has an average power efficiency of 81.6 percent and is suitable for wireless standards with bandwidths up to 20MHz compared to the relatively lower efficiencies and bandwidths of state of the art modulators. A class-A PA is shown to promise an average power efficiency of 21.3 percent when the bias current is controlled dynamically and the supply voltage is varied using the proposed supply modulator. This is a significant improvement over the poor average efficiency of 1.06 percent for a fixed bias conventional linear class A PA. The project has been simulated using the TSMC 0.18 micrometer technology.

Turkson, Richard

2011-08-01T23:59:59.000Z

257

RF & Microwave Systems Group The RF & Microwave Systems  

E-Print Network (OSTI)

for Technology Transfer. Tagging, Tracking, and Locating Systems TTL technologies are on the verge and development (R&D) geared toward supplying robust communications for extreme environments; global tagging, tracking, and locating (TTL) systems; and RF- and microwave- based measurement and processing systems

258

Smart Radio Spectrum Management for Cognitive Radio  

E-Print Network (OSTI)

Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In this work, a fuzzy logic based system for spectrum management is proposed where the radio can share unused spectrum depending on some parameters like distance, signal strength, node velocity and availability of unused spectrum. The system is simulated and is found to give satisfactory results.

Bhattacharya, Partha Pratim; Gera, Rishita; Agarwal, Anjali

2011-01-01T23:59:59.000Z

259

Simulation of synchrotron motion with rf noise  

Science Conference Proceedings (OSTI)

The theoretical formulation is described that is behind an algorithm for synchrotron phase-space tracking with rf noise and some preliminary simulation results of bunch diffusion under rf noise obtained by actual tracking.

Leemann, B.T.; Forest, E.; Chattopadhyay, S.

1986-08-01T23:59:59.000Z

260

MSTC - Microsystems Science, Technology, and Components - RF...  

NLE Websites -- All DOE Office Websites (Extended Search)

band RF input and supplies N identical outputs (N4 or 8). SiGe, GaAs, GaN RFICs. Passive RF detectors - Pyroelectric microdetectors that produce a DC output proportional to...

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

RF transceiver reference design for third generation W-CDMA cellular handset  

Science Conference Proceedings (OSTI)

A radio frequency transceiver reference design for third generation UTRA/FDD W-CDMA cellular handset is presented in this paper, A number of commercial RFICs are analyzed by considering the heterodyne architecture implementation of the transceiver. Requirements ...

Sew Kin Wong; Sze Wei Lee; Moh Lim Sim

2005-05-01T23:59:59.000Z

262

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

E-Print Network (OSTI)

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 ...

Shields, Brendan John

2006-01-01T23:59:59.000Z

263

Some issues on the RF system in the 3 GeV Fermilab pre-booster  

SciTech Connect

Some issues are presented on the rf system in the future Fermilab prebooster, which accelerates 4 bunches each containing 0.25 x 10{sub 14} protons from 1 to 3 GeV kinetic energy. The problem of beam loading is discussed. The proposal of having a non-tunable fixed-frequency rf system is investigated. Robinson's criteria for phase stability are checked and possible Robinson instability growth is computed.

Ng, K. Y.

1998-06-01T23:59:59.000Z

264

Charge-domain signal processing of direct RF sampling mixer with discrete-time filters in Bluetooth and GSM receivers  

Science Conference Proceedings (OSTI)

RF circuits for multi-GHz frequencies have recently migrated to low-cost digital deep-submicron CMOS processes. Unfortunately, this process environment, which is optimized only for digital logic and SRAM memory, is extremely unfriendly for conventional ...

Yo-Chuol Ho; Robert Bogdan Staszewski; Khurram Muhammad; Chih-Ming Hung; Dirk Leipold; Kenneth Maggio

2006-04-01T23:59:59.000Z

265

RF coupler for high-power CW FEL photoinjector  

SciTech Connect

A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. The design presently under way is a 100-mA 2.5-cell {pi}-mode, 700-MHz, normal conducting demonstration CW RF photoinjector. This photoinjector will be capable of accelerating 3 nC per bunch with an emittance at the wiggler less than 10 mm-mrad. The paper presents results for the RF coupling from ridged wave guides to hte photoinjector RF cavity. The LEDA and SNS couplers inspired this 'dog-bone' design. Electromagnetic modeling of the coupler-cavity system has been performed using both 2-D and 3-D frequency-domain calculations, and a novel time-domain approach with MicroWave Studio. These simulations were used to adjust the coupling coefficient and calculate the power-loss distribution on the coupling slot. The cooling of this slot is a rather challenging thermal management project.

Kurennoy, S. (Sergey); Young, L. M. (Lloyd M.)

2003-01-01T23:59:59.000Z

266

Determination of Ionospheric Current Systems by Measuring the Phase Shift on Amateur Satellite Frequencies  

E-Print Network (OSTI)

We investigate the possibility of measuring and using the phase delay of radio frequency transmissions in the amateur satellite band as a method to determine the distribution of currents systems in the ionosphere. The amateur satellite transmissions at 7M Hz, 14M Hz, and 144M Hz are low enough for Faraday rotation to cause a significant phase delay on the propagating signals in addition to the phase delay produced by the total electron content (TEC) in the ionosphere. The ionosphere in the E and F regions is modeled as an equivalent thin planar shell of collision free cold plasma 100 km in thickness located in an altitude range of 100 ? 200 km. The earth’s magnetic field is superposed with a weaker magnetic field due to a narrow Gaussian strip of current representing an ionospheric electrojet. The profile of the current system is obtained by numerically optimizing the Appleton-Hartree dispersion relation for rays of simulated radio frequency (RF) signals that propagate through the ionosphere shell. The optimization procedure is performed with a differential evolution algorithm. From the optimization procedure, we obtain the ionosphere total electron content (TEC) and the strength, profile, and orientation of the ionospheric current system. (53 pages) iv

Prajwal M Kasturi

2013-01-01T23:59:59.000Z

267

Delta-sigma (??) frequency synthesizers for wireless applications  

Science Conference Proceedings (OSTI)

This paper describes the state-of-the-art design approaches to delta-sigma (@D@S) frequency synthesizers for wireless transceiver applications. Various synthesizer architectures, including the integer and fractional-N synthesizers, and frequency-to-digital ... Keywords: Frequency synthesizers, Frequency-to-digital converters, RF transmitters, Sigma-delta modulation

Bertan Bakkaloglu; Sayfe Kiaei; Bikram Chaudhuri

2007-01-01T23:59:59.000Z

268

RESULTS FROM A DEMONSTRATION OF RF-BASED UF6 CYLINDER ACCOUNTING AND TRACKING SYSTEM INSTALLED AT A USEC FACILITY  

SciTech Connect

Approved industry-standard cylinders are used globally for storing and transporting uranium hexafluoride (UF{sub 6}) at uranium enrichment plants and processing facilities. To verify that no diversion or undeclared production of nuclear material involving UF{sub 6} cylinders at the facility has occurred, the International Atomic Energy Agency (IAEA) conducts periodic, labor-intensive physical inspections to validate facility records, cylinder identities, and cylinder weights. A reliable cylinder monitoring system that would improve overall inspector effectiveness would be a significant improvement to the current international safeguards inspection regime. Such a system could include real-time unattended monitoring of cylinder movements, situation-specific rules-based event detection algorithms, and the capability to integrate with other types of safeguards technologies. This type of system could provide timely detection of abnormal operational activities that may be used to ensure more appropriate and efficient responses by the IAEA. A system of this type can reduce the reliance on paper records and have the additional benefit of facilitating domestic safeguards at the facilities at which it is installed. A radio-frequency (RF)-based system designed to track uranium hexafluoride (UF{sub 6}) cylinders during processing operations was designed, assembled, and tested at the United States Enrichment Corporation (USEC) facility in Portsmouth, Ohio, to determine the operational feasibility and durability of RF technology. The overall objective of the effort was to validate the robustness of RF technology for potential use as a future international safeguards tool for tracking UF6 cylinders at uranium-processing facilities. The results to date indicate that RF tags represent a feasible technique for tracking UF{sub 6} cylinders in operating facilities. Additional work will be needed to improve the operational robustness of the tags for repeated autoclave processing and to add tamper-indicating and data authentication features to some of the pertinent system components. Future efforts will focus on these needs along with implementing protocols relevant to IAEA safeguards. The work detailed in this report demonstrates the feasibility of constructing RF devices that can survive the operational rigors associated with the transportation, storage, and processing of UF6 cylinders. The system software specially designed for this project is called Cylinder Accounting and Tracking System (CATS). This report details the elements of the CATS rules-based architecture and its use in safeguards-monitoring and asset-tracking applications. Information is also provided on improvements needed to make the technology ready, as well as options for improving the safeguards aspects of the technology. The report also includes feedback from personnel involved in the testing, as well as individuals who could utilize an RF-based system in supporting the performance of their work. The system software was set up to support a Mailbox declaration, where a declaration can be made either before or after cylinder movements take place. When the declaration is made before cylinders move, the operators must enter this information into CATS. If the IAEA then shows up unexpectedly at the facility, they can see how closely the operational condition matches the declaration. If the declaration is made after the cylinders move, this provides greater operational flexibility when schedules are interrupted or are changed, by allowing operators to declare what moves have been completed. The IAEA can then compare where cylinders are with where CATS or the system says they are located. The ability of CATS to automatically generate Mailbox declarations is seen by the authors as a desirable feature. The Mailbox approach is accepted by the IAEA but has not been widely implemented (and never in enrichment facilities). During the course of this project, we have incorporated alternative methods for implementation.

Pickett, Chris A [ORNL; Kovacic, Donald N [ORNL; Morgan, Jim [Innovative Solutions; Younkin, James R [ORNL; Carrick, Bernie [USEC; Ken, Whittle [USEC; Johns, R E [Pacific Northwest National Laboratory (PNNL)

2008-09-01T23:59:59.000Z

269

Algorithms for irreducible infeasible subset detection in CSP - Application to frequency planning and graph k-coloring.  

E-Print Network (OSTI)

??The frequency assignment (FAP) consists in assigning the frequency on the radio links of a network which satisfiesthe electromagnetic interference among the links. Given the… (more)

Hu, Jun

2012-01-01T23:59:59.000Z

270

Automatic calibration of modulated fractional-N frequency synthesizers  

E-Print Network (OSTI)

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 ...

McMahill, Dan

2001-01-01T23:59:59.000Z

271

Rf System for the NLCTA  

Science Conference Proceedings (OSTI)

This paper describes an X-Band RF system for the Next Linear Collider Test Accelerator. The RF system consists of a 90 MeV injector and a 540 MeV linac. The main components of the injector are two low-Q single-cavity prebunchers and two 0.9-m-long detuned accelerator sections. The linac system consists of six 1.8-m-long detuned and damped detuned accelerator sections powered in pairs. The rf power generation, compression, delivery, distribution and measurement systems consist of klystrons, SLEDII energy compression systems, rectangular waveguides, magic-T's, and directional couplers. The phase and amplitude for each prebuncher is adjusted via a magic-T type phase shifter/attenuator. Correct phasing between the two 0.9 m accelerator sections is obtained by properly aligning the sections and adjusting two squeeze type phase shifters. Bunch phase and bunch length can be monitored with special microwave cavities and measurement systems. The design, fabrication, microwave measurement, calibration, and operation of the sub-systems and their components are briefly presented.

Wang, J.W.; /SLAC; Adolphsen, C.; Eichner, J.; Fuller, R.W.; Gold, S.L.; Hanna, S.M.; Hoag, H.A.; Holmes, S.G.; Koontz, R.F.; Lavine, Theodore L.; Loewen, R.J.; Miller, R.H.; Nantista, C.D.; Pope, R.; Rifkin, J.; Ruth, R.D.; Tantawi, S.G.; Vlieks, A.E.; Wilson, Z.; Yeremian, A.; /SLAC

2011-08-26T23:59:59.000Z

272

Single electron beam rf feedback free electron laser  

DOE Patents (OSTI)

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.

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

1981-02-11T23:59:59.000Z

273

MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS  

SciTech Connect

We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.

Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

2012-09-10T23:59:59.000Z

274

Interaction Between AM Radio Broadcast Antennas and Overhead Power Lines  

Science Conference Proceedings (OSTI)

Metallic structures, power lines or otherwise, can affect the operation of AM radio broadcast station antennas if the dimensions of those structures are related to the wavelength of the radio signal at the station's operating frequency. For power lines, the dimensions of interest can be either the height of the support structures themselves or the length of a loop formed by adjacent structures, the shield wires connecting them, and the return path in the earth. When resonance occurs between the power lin...

2012-05-10T23:59:59.000Z

275

Closed-cell 201.25 MHz RF structures for a muon cooling channel  

DOE Green Energy (OSTI)

We report on the research and development of high gradient low frequency closed-cell structures for possible use in a muon cooling channel. The presence of strong magnetic fields precludes the use of superconducting RF. These multi-cell structures have the ''beam iris'' closed by conducting oils, grids of tubes or other isolating structures. This greatly increases the shunt impedance and also allows the individually powered cells to be set independently to any phase. The isolating structure must be made using a very small amount of low-Z material to avoid unacceptable scattering of the muon beam. Various cell designs and methods of closure are presented and compared. The problems of RF heating and breakdown at high gradient are discussed with regard to the vulnerable isolating structures. RF, thermal and stress analyses are presented and the integration of the RF with the solenoid cryostat and liquid hydrogen absorbers is considered.

Rimmer, R.; Hartman, N.; Ladran, A.; Li, D.; Moretti, A.; Jurgens, T.

2001-06-01T23:59:59.000Z

276

Overview of the RF Systems for LCLS  

SciTech Connect

The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time [1]. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and peak current phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these tight constraints.

McIntosh, P.; Akre, R.; Boyce, R.; Emma, P.; Hill, A.; Rago, C.; /SLAC

2005-06-15T23:59:59.000Z

277

Overview of the RF Systems for LCLS  

E-Print Network (OSTI)

The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these constraints.

McIntosh, Peter; Boyce, Richard; Emma, Paul; Hill, Alan; Rago, Carl

2005-01-01T23:59:59.000Z

278

Decay Study of {sup 257}Rf  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti, n){sup 257}Rf. Reaction products were separated by the Argonne Fragment Mass Analyzer. Radioactive decay and spontaneous fission of {sup 257}Rf and its decay products were investigated. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup 42} {mu}S, was discovered by detecting internal conversion electrons followed by alpha decays. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal-conversion electrons which were succeeded by alpha decay, with a half-life of 4.1{sub -1.3}{sup +2.4} s, was observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf, or from another isomer in {sup 257}Rf.

Qian, J.; Heinz, A.; Winkler, R. [Yale University, New Haven, CT 06511 (United States); Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.; Peterson, D.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Pardo, R. C.; Robinson, A.; Scott, R.; Vondrasek, R.; Wang, X.; Zhu, S. [Argonne National Laboratory, Argonne, IL 60439 (United States)] (and others)

2009-03-04T23:59:59.000Z

279

Radio Astronomy Software Defined Receiver Project  

SciTech Connect

The paper describes a Radio Astronomy Software Defined Receiver (RASDR) that is currently under development. RASDR is targeted for use by amateurs and small institutions where cost is a primary consideration. The receiver will operate from HF thru 2.8 GHz. Front-end components such as preamps, block down-converters and pre-select bandpass filters are outside the scope of this development and will be provided by the user. The receiver includes RF amplifiers and attenuators, synthesized LOs, quadrature down converters, dual 8 bit ADCs and a Signal Processor that provides firmware processing of the digital bit stream. RASDR will interface to a user s PC via a USB or higher speed Ethernet LAN connection. The PC will run software that provides processing of the bit stream, a graphical user interface, as well as data analysis and storage. Software should support MAC OS, Windows and Linux platforms and will focus on such radio astronomy applications as total power measurements, pulsar detection, and spectral line studies.

Vacaliuc, Bogdan [ORNL; Leech, Marcus [Shirleys Bay Radio Astronomy Consortium; Oxley, Paul [Retired; Flagg, Richard [Retired; Fields, David [ORNL

2011-01-01T23:59:59.000Z

280

Frequency scaling of linear super-colliders  

SciTech Connect

The development of electron-positron linear colliders in the TeV energy range will be facilitated by the development of high-power rf sources at frequencies above 2856 MHz. Present S-band technology, represented by the SLC, would require a length in excess of 50 km per linac to accelerate particles to energies above 1 TeV. By raising the rf driving frequency, the rf breakdown limit is increased, thereby allowing the length of the accelerators to be reduced. Currently available rf power sources set the realizable gradient limit in an rf linac at frequencies above S-band. This paper presents a model for the frequency scaling of linear colliders, with luminosity scaled in proportion to the square of the center-of-mass energy. Since wakefield effects are the dominant deleterious effect, a separate single-bunch simulation model is described which calculates the evolution of the beam bunch with specified wakefields, including the effects of using programmed phase positioning and Landau damping. The results presented here have been obtained for a SLAC structure, scaled in proportion to wavelength.

Mondelli, A.; Chernin, D.; Drobot, A.; Reiser, M.; Granatstein, V.

1986-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Characteristics of multiantenna rf ion source  

Science Conference Proceedings (OSTI)

We have developed a new multiantenna rf ion source for neutral beam injection and studied the effects of different antennas connected in parallel

T. Shoji; Y. Oka; NBI Group

2006-01-01T23:59:59.000Z

282

Passive RF Components - Microsystems Science, Technology, and...  

NLE Websites -- All DOE Office Websites (Extended Search)

Passive RF Components Microsystems Home Custom Microsystems Solutions Microsystems R&D Services Capabilities and Technologies Facilities Trusted Microsystems General Info About Us...

283

Recent Studies of RF Breakdown Physics in Normal Conducting Cavities  

SciTech Connect

The operating accelerating gradient in normal conducting accelerating structures is often limited by rf breakdown. The behavior of the rf breakdown depends on multiple parameters, including the input rf power, rf circuit, cavity shape and material. Here we discuss recent experimental data and theoretical studies of rf breakdown physics.

Dolgashev, Valery; /SLAC

2012-06-11T23:59:59.000Z

284

eRadio : empowerment through community Web radio  

E-Print Network (OSTI)

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, ...

Gomez-Monroy, Carla, 1977-

2004-01-01T23:59:59.000Z

285

Sunpentown: ENERGY STAR Referral (RF-330SS) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

ENERGY STAR Referral (RF-330SS) Sunpentown: ENERGY STAR Referral (RF-330SS) May 10, 2013 DOE referred the matter of Sunpentown-brand refrigerator, model RF-330SS, manufactured by...

286

Samsung: ENERGY STAR Referral (RF26VAB) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Samsung: ENERGY STAR Referral (RF26VAB) Samsung: ENERGY STAR Referral (RF26VAB) March 16, 2010 DOE referred the matter of Samsung refrigerator-freezer model RF26VAB to the U.S....

287

Satellite Radio: Its Global Impact  

E-Print Network (OSTI)

Geo-Stationary High-powered Satellites · Processed and Transparent Payloads · Solar-Powered Provides A is the satellite transmit characteristics, determined by state-of art satellite power, coverage area; B is Receive WorldSpace XM Sirius MBSAT #12;8 Satellite Radio: A Confluence of Technologies Radio Radio Internet

Udgaonkar, Jayant B.

288

RADIO RANGING DEVICE  

DOE Patents (OSTI)

A radio ranging device is described. It utilizes a super regenerative detector-oscillator in which echoes of transmitted pulses are received in proper phase to reduce noise energy at a selected range and also at multiples of the selected range.

Nieset, R.T.

1961-05-16T23:59:59.000Z

289

R&D ERL: Low level RF  

SciTech Connect

A superconducting RF (SRF) Energy Recovery Linac (ERL) is currently under development at the Collider-Accelerator Department (C-AD) at Brookhaven National Laboratory (BNL). The major components from an RF perspective are (a) a 5-cell SRF ERL cavity, (b) an SRF photocathode electron gun, and (c) a drive laser for the photocathode gun. Each of these RF subsystems has its own set of RF performance requirements, as well as common requirements for ensuring correct synchronism between them. A low level RF (LLRF) control system is currently under development, which seeks to leverage both technology and experience gained from the recently commissioned RHIC LLRF system upgrade. This note will review the LLRF system requirements and describe the system to be installed at the ERL.

Smith, K.

2010-01-15T23:59:59.000Z

290

The upgraded rf system for the AGS and high intensity proton beams  

SciTech Connect

The AGS has been upgraded over the past three years to produce a record beam intensity of 6 {times} 10{sup 13} protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system`s performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading.

Brennan, J.M. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.

1995-05-01T23:59:59.000Z

291

Mitigating the effects of RF interference through RSSI-Based error recovery  

Science Conference Proceedings (OSTI)

On a common sensor node platform (Telos) we sample RSSI with high frequency during packet reception. We find that a packet collision (RF interference) often manifests as a measurable, temporal increase in RSSI. We investigate how the receiver ... Keywords: ARQ, interference mitigation, packet combining

Jan-Hinrich Hauer; Andreas Willig; Adam Wolisz

2010-02-01T23:59:59.000Z

292

Linear Gain for the Microbunching Instability in an RF Compressor  

E-Print Network (OSTI)

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

Venturini, M.

2010-01-01T23:59:59.000Z

293

The Status of Normal Conducting RF (NCRF) Guns, a Summary of the ERL2005 Workshop  

Science Conference Proceedings (OSTI)

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DF in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.

Dowell, D.H.; /SLAC; Lewellen, J.W.; /Argonne; Nguyen, D.; /Los Alamos; Rimmer, R.; /Jefferson Lab

2006-03-13T23:59:59.000Z

294

The status of normal conducting RF (NCRF) guns; a summary of the ERL2005 Workshop  

SciTech Connect

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DF in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.

D.H. Dowell; J.W. Lewellen; D. Nguyen; R.A. Rimmer

2005-03-19T23:59:59.000Z

295

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

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.

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

2008-01-01T23:59:59.000Z

296

Review of the APS SR RF systems.  

DOE Green Energy (OSTI)

The Advanced Photon Source (APS) is a 7-GeV full energy storage ring (SR) for generating synchrotron radiation with an injector. The storage ring cavities consist of four groups of four single cells powered by up to four 1-MW klystrons for up to 300-mA operation. A review of the operation of the rf system as well as rf-related beam dynamics is presented. This review includes rf power distribution, low-level feedback, control law, beam loading, beam instabilities, higher-order modes, and beam-induced multipactoring.

Song, J.J.; Cours, A.; Grelick, A.; Harkay, K.; Horan, D.; Kang, Y.W.; Kustom, R.L.; Nassiri, A.; Pile, G.; Smith, T.L.

1998-03-31T23:59:59.000Z

297

Degreasing and cleaning superconducting RF Niobium cavities  

Science Conference Proceedings (OSTI)

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.

Rauchmiller, Michael; Kellett, Ron; /Fermilab

2011-09-01T23:59:59.000Z

298

RF Micro Devices | Open Energy Information  

Open Energy Info (EERE)

National Center for Photovoltaics Partnership Year 2009 LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now RF Micro Devices is a company located in...

299

SLAC Linac RF Performance for LCLS *  

E-Print Network (OSTI)

The Linac Coherent Light Source (LCLS) project at SLAC uses a dense 15 GeV electron beam passing through a long undulator to generate extremely bright x-rays at 1.5 angstroms. The project requires electron bunches with a nominal peak current of 3.5kA and bunch lengths of 0.020mm (70fs). The bunch compression techniques used to achieve the high brightness impose challenging tolerances on the accelerator RF phase and amplitude. The results of measurements on the existing SLAC linac RF phase and amplitude stability are summarised and improvements needed to meet the LCLS tolerances are discussed. 1 LCLS RF REQUIREMENTS LCLS requires the SLAC linac to perform with tolerances on RF phase and amplitude stability which are beyond all previous requirements. The LCLS is divided into four linacs L0, L1, L2, and L3 [1]. The phase and amplitude tolerances for the four linacs operated at S-

unknown authors

2000-01-01T23:59:59.000Z

300

Deeply scaled CMOS for RF power applications  

E-Print Network (OSTI)

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 ...

Scholvin, Jörg, 1976-

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Vortex formation during rf heating of plasma  

SciTech Connect

Experiments on a test plasma show that the linear theory of waveguide coupling to slow plasma waves begins to break down if the rf power flux exceeds approx. 30 W/cm/sup 2/. Probe measurements reveal that within 30 ..mu..s an undulation appears in the surface plasma near the mouth of the twin waveguide. This surface readjustment is part of a vortex, or off-center convective cell, driven by asymmetric rf heating of the plasma column.

Motley, R.W.

1980-05-01T23:59:59.000Z

302

High Power RF Sources for Accelerators  

SciTech Connect

This presentation describes RF sources developed and under development at Calabazas Creek Research, Inc. for driving high power accelerators and colliders. The RF sources range from L-Band to W-Band and power levels from 10s of kilowatts CW to 200 MW pulsed. The configurations include standard klystrons, multiple beam klystrons, sheet beam devices, and gyroklystrons. The basic parameters are presented with a basic description of operation and applications.

Ives, Lawrence; Read, Michael; Neilson, Jeff; Borchard, Philipp; Mizuhara, Max [Calabazas Creek Research, Inc., 690 Port Drive, San Mateo, CA 94404 (United States); Lawson, Wesley [Insitute for Research in Applied Physics, University of Maryland, College Park, MD 20742 (United States)

2006-11-27T23:59:59.000Z

303

Higher layer issues in cognitive radio network  

Science Conference Proceedings (OSTI)

Cognitive radio networks are smart networks that automatically sense the channel and adjust the network parameters accordingly. Cognitive radio is an emerging technology that enables the dynamic deployment of highly adaptive radios that are built upon ... Keywords: cognitive radio network (CRN), issues, routing issues, security issues, software defined radio

Saed Alrabaee; Anjali Agarwal; Nishith Goel; Marzia Zaman; Mahmoud Khasawneh

2012-08-01T23:59:59.000Z

304

Self isolating high frequency saturable reactor  

DOE Patents (OSTI)

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.

Moore, James A. (Powell, TN)

1998-06-23T23:59:59.000Z

305

Cerenkov radio pulses from electromagnetic showers in the time domain  

Science Conference Proceedings (OSTI)

The electric field of the Cerenkov radio pulse produced by a single charged particle track in a dielectric medium is derived from first principles. An algorithm is developed to obtain the pulse in the time domain for numerical calculations. The algorithm is implemented in a Monte Carlo simulation of electromagnetic showers in dense media (specifically designed for coherent radio emission applications) as might be induced by interactions of ultrahigh energy neutrinos. The coherent Cerenkov radio emission produced by such showers is obtained simultaneously both in the time and frequency domains. A consistency check performed by Fourier transforming the pulse in time and comparing it to the frequency spectrum obtained directly in the simulations yields, as expected, fully consistent results. The reversal of the time structure inside the Cerenkov cone and the signs of the corresponding pulses are addressed in detail. The results, besides testing algorithms used for reference calculations in the frequency domain, shed new light into the properties of the radio pulse in the time domain. The shape of the pulse in the time domain is directly related to the depth development of the excess charge in the shower and its width to the observation angle with respect to the Cerenkov direction. This information can be of great practical importance for interpreting actual data.

Alvarez-Muniz, Jaime; Romero-Wolf, Andres; Zas, Enrique [Depto. de Fisica de Particulas and Instituto Galego de Fisica de Altas Enerxias, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Depto. de Fisica de Particulas and Instituto Galego de Fisica de Altas Enerxias, Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)

2010-06-15T23:59:59.000Z

306

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

E-Print Network (OSTI)

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. ...

Benedick, Andrew John

2011-01-01T23:59:59.000Z

307

RF plasma sources for neutral-beam-injection systems. Phase I: definition study. Final report  

DOE Green Energy (OSTI)

The key design issues driving the selection of a plasma generation method are discussed. The main programmatic issue in source selection was ease of implementation on existing and planned neutral beam systems. The two source concepts selected for detailed consideration, one employing electron cyclotron heating at microwave frequencies and one employing radio frequency induction heating, are described. Preliminary RFI hydrogen discharge experiments in a geometry suitable for neutral beam system application are described.

Not Available

1981-11-01T23:59:59.000Z

308

A bio-inspired active radio-frequency silicon cochlea  

E-Print Network (OSTI)

Fast wideband spectrum analysis is expensive in power and hardware resources. We show that the spectrum-analysis architecture used by the biological cochlea is extremely efficient: analysis time, power and hardware usage ...

Sarpeshkar, Rahul

309

UTags-Long Range Ultra Wideband Passive Radio Frequency ...  

Giving animals in need a HOME. November 14, 2013. LLNL, Intel, Cray produce big data machine. ... for the Department of Energy's National Nuclear Security Administration

310

Quantum dots and radio-frequency electrometry in silicon.  

E-Print Network (OSTI)

??This thesis describes the development and demonstration of a new technique for the fabrication of well-defined quantum dots in a bulk silicon substrate, for potential… (more)

Angus, Susan J.

2008-01-01T23:59:59.000Z

311

NIST SP 800-98, Guidelines for Securing Radio Frequency ...  

Science Conference Proceedings (OSTI)

... business risks associated with implementing RFID technology. ... GUIDELINES FOR SECURING RFID SYSTEMS ... to understand later material in the ...

2012-02-09T23:59:59.000Z

312

Electronic and Embedded Systems Low-frequency radio identification  

E-Print Network (OSTI)

-cost hardware and easy installation. Users: Stewards of high-valued assets, protective forces, DOE, NNSA, DOD

313

Compact, low power radio frequency cavity for femtosecond electron microscopy  

Science Conference Proceedings (OSTI)

Reported here is the design, construction, and characterization of a small, power efficient, tunable dielectric filled cavity for the creation of femtosecond electron bunches in an existing electron microscope without the mandatory use of femtosecond lasers. A 3 GHz pillbox cavity operating in the TM{sub 110} mode was specially designed for chopping the beam of a 30 keV scanning electron microscope. The dielectric material used is ZrTiO{sub 4}, chosen for the high relative permittivity ({epsilon}{sub r}= 37 at 10 GHz) and low loss tangent (tan {delta}= 2 x 10{sup -4}). This allows the cavity radius to be reduced by a factor of six, while the power consumption is reduced by an order of magnitude compared to a vacuum pillbox cavity. These features make this cavity ideal as a module for existing electron microscopes, and an alternative to femtosecond laser systems integrated with electron microscopes.

Lassise, A.; Mutsaers, P. H. A.; Luiten, O. J. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2012-04-15T23:59:59.000Z

314

Radio-frequency quadrupole resonator for linear accelerator  

DOE Patents (OSTI)

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.

Moretti, A.

1982-10-19T23:59:59.000Z

315

NIST Time and Frequency Radio Stations: WWV, WWVH, and ...  

Science Conference Proceedings (OSTI)

... that would later also become the home of WWV. ... They include heating coils and run year round. ... company provides power through an oil-filled, 500 ...

2012-10-30T23:59:59.000Z

316

19th Topical Conference on Radio Frequency Power in Plasmas ...  

NLE Websites -- All DOE Office Websites (Extended Search)

Join Our Mailing List A Collaborative National Center for Fusion & Plasma Research Search form Search Search Home About Overview Learn More Visiting PPPL History...

317

Narrowband high temperature superconducting receiver for low frequency radio waves  

DOE Patents (OSTI)

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

Reagor, David W. (Los Alamos, NM)

2001-01-01T23:59:59.000Z

318

NIST Time and Frequency Radio Stations: WWV, WWVH, and ...  

Science Conference Proceedings (OSTI)

... year, depending on weather conditions and irrigation ... The air conditioning units currently in operation ... kVA, Y-connected three-phase transformer. ...

2011-11-16T23:59:59.000Z

319

Radio Remote Sensing of the Corona and the Solar Wind  

E-Print Network (OSTI)

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

Steven R. Spangler; Catherine A. Whiting

2008-09-26T23:59:59.000Z

320

PREDICTION OF TYPE II SOLAR RADIO BURSTS BY THREE-DIMENSIONAL MHD CORONAL MASS EJECTION AND KINETIC RADIO EMISSION SIMULATIONS  

Science Conference Proceedings (OSTI)

Type II solar radio bursts are the primary radio emissions generated by shocks and they are linked with impending space weather events at Earth. We simulate type II bursts by combining elaborate three-dimensional MHD simulations of realistic coronal mass ejections (CMEs) at the Sun with an analytic kinetic radiation theory developed recently. The modeling includes initialization with solar magnetic and active region fields reconstructed from magnetograms of the Sun, a flux rope of the initial CME dimensioned with STEREO spacecraft observations, and a solar wind driven with averaged empirical data. We demonstrate impressive accuracy in time, frequency, and intensity for the CME and type II burst observed on 2011 February 15. This implies real understanding of the physical processes involved regarding the radio emission excitation by shocks and supports the near-term development of a capability to predict and track these events for space weather prediction.

Schmidt, J. M.; Cairns, Iver H. [School of Physics, University of Sydney, NSW 2006 (Australia); Hillan, D. S., E-mail: jschmidt@physics.usyd.edu.au [CSIRO Earth Science and Resource Engineering, North Ryde, NSW 2113 (Australia)

2013-08-20T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

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

Science Conference Proceedings (OSTI)

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.

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

2012-12-21T23:59:59.000Z

322

Interplanetary Radio Transmission Through Serial Ionospheric and Material Barriers  

Science Conference Proceedings (OSTI)

A usual first principle in planning radio astronomy observations from the earth is that monitoring must be carried out well above the ionospheric plasma cutoff frequency (~5 MHz). Before space probes existed, radio astronomy was almost entirely done above 6 MHz, and this value is considered a practical lower limit by most radio astronomers. Furthermore, daytime ionization (especially D-layer formation) places additional constraints on wave propagation, and waves of frequency below 10-20 MHz suffer significant attenuation. More careful calculations of wave propagation through the earth s ionosphere suggest that for certain conditions (primarily the presence of a magnetic field) there may be a transmission window well below this assumed limit. Indeed, for receiving extraterrestrial radiation below the ionospheric plasma cutoff frequency, a choice of VLF frequency appears optimal to minimize loss. The calculation, experimental validation, and conclusions are presented here. This work demonstrates the possibility of VLF transmission through the ionosphere and various subsequent material barriers. Implications include development of a new robust communications channel, communications with submerged or subterranean receivers / instruments on or offworld, and a new approach to SETI.

Fields, David [ORNL; Kennedy, Robert G [ORNL; Roy, Kenneth I [ORNL; Vacaliuc, Bogdan [ORNL

2013-01-01T23:59:59.000Z

323

500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application  

SciTech Connect

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

Chu, Tak Sum; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore; Barty, Christopher; /LLNL, Livermore; Gibson, David; /LLNL, Livermore; Hartemann, Fred; /LLNL, Livermore; Marsh, Roark; /LLNL, Livermore; Siders, Craig; /LLNL, Livermore; Adolphsen, Chris; /SLAC; Jongewaard, Erik; /SLAC; Raubenheimer, Tor; /SLAC; Tantawi, Sami; /SLAC; Vlieks, Arnold; /SLAC; Wang, Juwen; /SLAC

2012-07-03T23:59:59.000Z

324

500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION  

Science Conference Proceedings (OSTI)

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C; Barty, C P; Adolphsen, C; Jongewaard, E; Tantawi, S; Vlieks, A; Wang, J W; Raubenheimer, T

2010-05-12T23:59:59.000Z

325

V-FASTR: THE VLBA FAST RADIO TRANSIENTS EXPERIMENT  

Science Conference Proceedings (OSTI)

Recent discoveries of dispersed, non-periodic impulsive radio signals with single-dish radio telescopes have sparked significant interest in exploring the relatively uncharted space of fast transient radio signals. Here we describe V-FASTR, an experiment to perform a blind search for fast transient radio signals using the Very Long Baseline Array (VLBA). The experiment runs entirely in a commensal mode, alongside normal VLBA observations and operations. It is made possible by the features and flexibility of the DiFX software correlator that is used to process VLBA data. Using the VLBA for this type of experiment offers significant advantages over single-dish experiments, including a larger field of view, the ability to easily distinguish local radio-frequency interference from real signals, and the possibility to localize detected events on the sky to milliarcsecond accuracy. We describe our software pipeline, which accepts short integration ({approx} ms) spectrometer data from each antenna in real time during correlation and performs an incoherent dedispersion separately for each antenna, over a range of trial dispersion measures. The dedispersed data are processed by a sophisticated detector and candidate events are recorded. At the end of the correlation, small snippets of the raw data at the time of the events are stored for further analysis. We present the results of our event detection pipeline from some test observations of the pulsars B0329+54 and B0531+21 (the Crab pulsar).

Wayth, Randall B.; Tingay, Steven J. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Brisken, Walter F.; Deller, Adam T. [NRAO, P.O. Box O, Socorro, NM 87801 (United States); Majid, Walid A.; Thompson, David R.; Wagstaff, Kiri L., E-mail: randall.wayth@icrar.org [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2011-07-10T23:59:59.000Z

326

Tubular RF cage field confinement cavity - Energy Innovation ...  

An RF cavity is provided with a plurality of tubes that are formed into a tubular cage in a predefined shape to define the RF cavity. A selected number of tubes and a ...

327

Klystron "efficiency loop" for the ALS storage ring RF system  

E-Print Network (OSTI)

EFFICIENCY LOOP” FOR THE ALS STORAGE RING RF SYSTEM* S.at the Advanced Light Source (ALS) in order to decrease thethe cavities. 1 INTRODUCTION ALS Storage Ring RF system is

Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth

2002-01-01T23:59:59.000Z

328

Transient beam loading in the ALS harmonic RF system  

E-Print Network (OSTI)

TRANSIENT BEAM LOADING IN THE ALS HARMONIC RF SYSTEM * J.as the Advanced Light Source (ALS), with moderately low beamharmonic RF system on the ALS storage ring consisting of 5

2000-01-01T23:59:59.000Z

329

A Trusted Hybrid Software Radio  

frequencies and communications standards. It would be capable of global interoperability across a variety of frequencies and communications standards.

330

BeginPackage "rfPack`" Modified 28 Jul 1999  

E-Print Network (OSTI)

voltage vRF, stable phase angle £ in units of 2¥ , and wavelength ¤ ." bucketHF::usage ¡ "bucketHF ¢ ,h compaction ¢ , an RF system with harmonic number h, peak voltage vRF, and stable phase angle £ in units of 2 with harmonic number h, peak voltage vRF, and stable phase angle £ in units of 2¥ , for particles of energy E

Keil, Eberhard

331

Eccentric superconducting RF cavity separator structure  

DOE Patents (OSTI)

Accelerator apparatus having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects.

Aggus, John R. (Shoreham, NY); Giordano, Salvatore T. (Port Jefferson, NY); Halama, Henry J. (Shoreham, NY)

1976-01-01T23:59:59.000Z

332

RF Breakdown of Metallic Surfaces in Hydrogen  

DOE Green Energy (OSTI)

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.

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

333

RF Design of the LCLS Gun  

Science Conference Proceedings (OSTI)

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.

Limborg-Deprey, C

2010-12-13T23:59:59.000Z

334

Cw rf operation of the FMIT RFQ  

SciTech Connect

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.

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

1985-01-01T23:59:59.000Z

335

Broadcasting in unreliable radio networks  

E-Print Network (OSTI)

Practitioners agree that unreliable links, which sometimes deliver messages and sometime do not, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set ...

Kuhn, Fabian

336

Broadcasting in Unreliable Radio Networks  

E-Print Network (OSTI)

Practitioners agree that unreliable links, which fluctuate between working and not working, are an important characteristic of wireless networks. In contrast, most theoretical models of radio networks fix a static set of ...

Oshman, Rotem

2010-06-08T23:59:59.000Z

337

Advances in Filter Miniaturization and Design/Analysis of RF MEMS Tunable Filters  

E-Print Network (OSTI)

The main purpose of this dissertation was to address key issues in the design and analysis of RF/microwave filters for wireless applications. Since RF/microwave filters are one of the bulkiest parts of communication systems, their miniaturization is one of the most important technological challenges for the development of compact transceivers. In this work, novel miniaturization techniques were investigated for single-band, dual-band, ultra-wideband and tunable bandpass filters. In single-band filters, the use of cross-shaped fractals in half-mode substrate-integrated-waveguide bandpass filters resulted in a 37 percent size reduction. A compact bandpass filter that occupies an area of 0.315 mm2 is implemented in 90-nm CMOS technology for 20 GHz applications. For dual-band filters, using half-mode substrate-integrated-waveguides resulted in a filter that is six times smaller than its full-mode counterpart. For ultra-wideband filters, using slow-wave capacitively-loaded coplanar-waveguides resulted in a filter with improved stopband performance and frequency notch, while being 25 percent smaller in size. A major part of this work also dealt with the concept of 'hybrid' RF MEMS tunable filters where packaged, off-the-shelf RF MEMS switches were used to implement high-performance tunable filters using substrate-integrated-waveguide technology. These 'hybrid' filters are very easily fabricated compared to current state-of-the-art RF MEMS tunable filters because they do not require a clean-room facility. Both the full-mode and half-mode substrate-integrated waveguide tunable filters reported in this work have the best Q-factors (93 - 132 and 75 - 140, respectively) compared to any 'hybrid' RF MEMS tunable filter reported in current literature. Also, the half-mode substrate-integrated waveguide tunable filter is 2.5 times smaller than its full-mode counterpart while having similar performance. This dissertation also presented detailed analytical and simulation-based studies of nonlinear noise phenomena induced by Brownian motion in all-pole RF MEMS tunable filters. Two independent mathematical methods are proposed to calculate phase noise in RF MEMS tunable filters: (1) pole-perturbation approach, and (2) admittance-approach. These methods are compared to each other and to harmonic balance noise simulations using the CAD-model of the RF MEMS switch. To account for the switch nonlinearity in the mathematical methods, a nonlinear nodal analysis technique for tunable filters is also presented. In summary, it is shown that output signal-to-noise ratio degradation due to Brownian motion is maximum for low fractional bandwidth, high order and high quality factor RF MEMS tunable filters. Finally, a self-sustained microwave platform to detect the dielectric constant of organic liquids is presented in this dissertation. The main idea is to use a voltage- controlled negative-resistance oscillator whose frequency of oscillation varies according to the organic liquid under test. To make the system self-sustained, the oscillator is embedded in a frequency synthesizer system, which is then digitally interfaced to a computer for calculation of dielectric constant. Such a system has potential uses in a variety of applications in medicine, agriculture and pharmaceuticals.

Sekar, Vikram

2011-08-01T23:59:59.000Z

338

Laser cooling and sympathetic cooling in a linear quadrupole rf trap  

E-Print Network (OSTI)

An investigation of the sympathetic cooling method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of rf heating rates on the ion temperature, trapping parameters, and the number of ions is obtained. New rf heating mechanism affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and the influence of the rf heating rates on the fluorescence lineshapes is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.

Ryjkov, Vladimir Leonidovich

2003-12-01T23:59:59.000Z

339

Amplitude calibration of a digital radio antenna array for measuring cosmic ray air showers  

E-Print Network (OSTI)

Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth's atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio antennas (LOPES experiment) an absolute amplitude calibration of the radio antennas including the full electronic chain of the data acquisition system is performed, in order to estimate absolute values of the electric field strength for these short radio pulses. This is mandatory, because the measured radio signals in the MHz frequency range have to be compared with theoretical estimates and with predictions from Monte Carlo simulations to reconstruct features of the primary cosmic particle. A commercial reference radio emitter is used to estimate frequency dependent correction factors for each single antenna of the radio antenna array. The expected received power is related to the power recorded by the full electronic chain. Systematic uncertainties due to different environmental conditions and the described calibration procedure are of order 20%.

S. Nehls; A. Hakenjos; M. J. Arts; J. Bluemer; H. Bozdog; W. A. van Cappellen; H. Falcke; A. Haungs; A. Horneffer; T. Huege; P. G. Isar; O. Kroemer

2008-02-28T23:59:59.000Z

340

Reviving Fossil Radio Plasma in Clusters of Galaxies by Adiabatic Compression in Environmental Shock Waves  

E-Print Network (OSTI)

We give for a plasma with a history of several expansion and contraction phases an analytical model of the evolution of a contained relativistic electron population under synchrotron, inverse Compton and adiabatic energy losses or gains. This is applied to different scenarios for evolution of radio plasma inside the cocoons of radio galaxies, after the activity of the central engine has ceased. It is demonstrated that fossil radio plasma with an age of even up to 2 Gyr can be revived by compression in a shock wave of large-scale structure formation, caused during the merging events of galaxy clusters, or by the accretion onto galaxy clusters. We argue, that this is a highly plausible explanation for the observed cluster radio relics, which are the regions of diffuse radio emission found in clusters of galaxies, without any likely parent radio galaxy seen nearby. An implication of this model is the existence of a population of diffuse, ultra-steep spectrum, very low frequency radio sources located inside and possibly outside of clusters of galaxies, tracing the revival of aged fossil radio plasma by the shock waves associated with large-scale structure formation.

Torsten A. Ensslin; Gopal-Krishna

2000-11-06T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

RUGGED CERAMIC WINDOW FOR RF APPLICATIONS  

Science Conference Proceedings (OSTI)

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.

MIKE NEUBAUER

2012-11-01T23:59:59.000Z

342

Ultra-wideband radios for time-of-flight-ranging and network position estimation  

DOE Patents (OSTI)

This invention provides a novel high-accuracy indoor ranging device that uses ultra-wideband (UWB) RF pulsing with low-power and low-cost electronics. A unique of the present invention is that it exploits multiple measurements in time and space for very accurate ranging. The wideband radio signals utilized herein are particularly suited to ranging in harsh RF environments because they allow signal reconstruction in spite of multipath propagation distortion. Furthermore, the ranging and positioning techniques discussed herein directly address many of the known technical challenges encountered in UWB localization regarding synchronization and sampling. In the method developed, noisy, corrupted signals can be recovered by repeating range measurements across a channel, and the distance measurements are combined from many locations surrounding the target in a way that minimizes the range biases associated to indirect flight paths and through-wall propagation delays.

Hertzog, Claudia A. (Houston, TX); Dowla, Farid U. (Castro Valley, CA); Dallum, Gregory E. (Livermore, CA); Romero, Carlos E. (Livermore, CA)

2011-06-14T23:59:59.000Z

343

Superconducting RF systems for eRHIC  

Science Conference Proceedings (OSTI)

The proposed electron-hadron collider eRHIC will consist of a six-pass 30-GeV electron Energy Recovery Linac (ERL) and one of RHIC storage rings operating with energy up to 250 GeV. The collider design extensively utilizes superconducting RF (SRF) technology in both electron and hadron parts. This paper describes various SRF systems, their requirements and parameters.

Belomestnykh S.; Ben-Zvi, I.; Brutus, J.C.; Hahn, H. et al

2012-05-20T23:59:59.000Z

344

Dynamics of Flat Bunches with Second Harmonic RF  

Science Conference Proceedings (OSTI)

We investigate the dynamics of longitudinally flat bunches created with a second harmonic cavity in a high energy collider. We study Landau damping in a second harmonic cavity with analytical and numerical methods. The latter include particle tracking and evolution of the phase space density. The results are interpreted in the context of possible application to the LHC. A possible path to a luminosity upgrade at the LHC is through the creation of longitudinally flat bunches. They can increase the luminosity roughly by 40% when the beam intensities are at the beam-beam limit. Lower momentum spread which can reduce backgrounds and make collimation easier as well lower peak fields which can mitigate electron cloud effects are other advantages. Use of a second harmonic rf system is a frequently studied method to create such flat bunches. Here we consider some aspects of longitudinal dynamics of these bunches in the LHC at top energy. First we consider intensity limits set by the loss of Landau damping against rigid dipole oscillations. Next we describe numerical simulations using both particle tracking and evolution of the phase space density. These simulations address the consequences of driving a bunch at a frequency that corresponds to the maximum of the synchrotron frequency.

Sen, Tanaji; /Fermilab; Bhat, Chandra; /Fermilab; Kim, Hyung Jin; /Fermilab; Ostiguy, Jean-Francois; /Fermilab

2010-05-01T23:59:59.000Z

345

RF Gun Photocathode Research at SLAC  

Science Conference Proceedings (OSTI)

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.

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

346

Experimental methodology for non-thermal effects of electromagnetic radiation on biologics  

E-Print Network (OSTI)

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 ...

Cox, Felicia C. A. I

2006-01-01T23:59:59.000Z

347

High Performance RF and Basdband Analog-to-Digital Interface for Multi-standard/Wideband Applications  

E-Print Network (OSTI)

The prevalence of wireless standards and the introduction of dynamic standards/applications, such as software-defined radio, necessitate the next generation wireless devices that integrate multiple standards in a single chip-set to support a variety of services. To reduce the cost and area of such multi-standard handheld devices, reconfigurability is desirable, and the hardware should be shared/reused as much as possible. This research proposes several novel circuit topologies that can meet various specifications with minimum cost, which are suited for multi-standard applications. This doctoral study has two separate contributions: 1. The low noise amplifier (LNA) for the RF front-end; and 2. The analog-to-digital converter (ADC). The first part of this dissertation focuses on LNA noise reduction and linearization techniques where two novel LNAs are designed, taped out, and measured. The first LNA, implemented in TSMC (Taiwan Semiconductor Manufacturing Company) 0.35Cm CMOS (Complementary metal-oxide-semiconductor) process, strategically combined an inductor connected at the gate of the cascode transistor and the capacitive cross-coupling to reduce the noise and nonlinearity contributions of the cascode transistors. The proposed technique reduces LNA NF by 0.35 dB at 2.2 GHz and increases its IIP3 and voltage gain by 2.35 dBm and 2dB respectively, without a compromise on power consumption. The second LNA, implemented in UMC (United Microelectronics Corporation) 0.13Cm CMOS process, features a practical linearization technique for high-frequency wideband applications using an active nonlinear resistor, which obtains a robust linearity improvement over process and temperature variations. The proposed linearization method is experimentally demonstrated to improve the IIP3 by 3.5 to 9 dB over a 2.5–10 GHz frequency range. A comparison of measurement results with the prior published state-of-art Ultra-Wideband (UWB) LNAs shows that the proposed linearized UWB LNA achieves excellent linearity with much less power than previously published works. The second part of this dissertation developed a reconfigurable ADC for multistandard receiver and video processors. Typical ADCs are power optimized for only one operating speed, while a reconfigurable ADC can scale its power at different speeds, enabling minimal power consumption over a broad range of sampling rates. A novel ADC architecture is proposed for programming the sampling rate with constant biasing current and single clock. The ADC was designed and fabricated using UMC 90nm CMOS process and featured good power scalability and simplified system design. The programmable speed range covers all the video formats and most of the wireless communication standards, while achieving comparable Figure-of-Merit with customized ADCs at each performance node. Since bias current is kept constant, the reconfigurable ADC is more robust and reliable than the previous published works.

Zhang, Heng

2010-12-01T23:59:59.000Z

348

RapidRadio: Signal Classification and Radio Deployment Framework  

Science Conference Proceedings (OSTI)

In this article, the RapidRadio framework for signal classification and receiver deployment is discussed. The framework is a productivity-enhancing tool that reduces the required knowledge base for implementing a receiver on an FPGA-based SDR platform. ... Keywords: FPGA, signal classification, system synthesis

Jorge A. Surís; Adolfo Recio; Peter Athanas

2012-08-01T23:59:59.000Z

349

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

DOE Patents (OSTI)

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.

Ormesher, Richard C.; Bickel, Douglas L

2012-10-23T23:59:59.000Z

350

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

SciTech Connect

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.

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

2011-01-01T23:59:59.000Z

351

Cognitive radio: an enabling technology for the green radio communications concept  

Science Conference Proceedings (OSTI)

In this paper, Cognitive Radio (CR) is proposed as an efficient technology to meet the Green communications concept. First of all, the concept of "green communications" is extended to the radio communications world. The main topics, described for example ... Keywords: cognitive radio, consumption, electromagnetic pollution, green communications, health, peak-to-average power ratio (PAPR), radio communications, sustainable development

Jacques Palicot

2009-06-01T23:59:59.000Z

352

Radio access network power management considering radio over fiber technique for 4G mobile system  

Science Conference Proceedings (OSTI)

Radio over fiber technique was suggested as excelent candidates for 4G radio access network considering large number mobile users. With higher number of base stations, a microwave link presents more disadvantages across base stations in relation to power ... Keywords: 4G mobile system, fiber dispersion, power manaegment, radio access network, radio over fiber

Jalal J. Hamad Ameen; Widad Ismail; Sevia M. Idrus

2011-03-01T23:59:59.000Z

353

GALAXY CLUSTER ENVIRONMENTS OF RADIO SOURCES  

SciTech Connect

Using the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD-type galaxy at the center of a cluster. We cross-correlated the SDSS and FIRST catalogs and measured the richness of the cluster environments surrounding both bent and straight multi-component radio sources. This led to the discovery and classification of a large number of galaxy clusters out to a redshift of z {approx} 0.5. We divided our sample into smaller subgroups based on their optical and radio properties. We find that FR I radio sources are more likely to be found in galaxy clusters than FR II sources. Further, we find that bent radio sources are more often found in galaxy clusters than non-bent radio sources. We also examined the environments around single-component radio sources and find that single-component radio sources are less likely to be associated with galaxy clusters than extended, multi-component radio sources. Bent, visually selected sources are found in clusters or rich groups {approx}78% of the time. Those without optical hosts in SDSS are likely associated with clusters at even higher redshifts, most with redshifts of z>0.7.

Wing, Joshua D.; Blanton, Elizabeth L., E-mail: jwing@bu.edu [Astronomy Department and Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)

2011-03-15T23:59:59.000Z

354

'Pirate' radio, convergence and reception in Zimbabwe  

Science Conference Proceedings (OSTI)

Using a qualitative research approach, this study examines the appropriation of digital technologies and their implications for the reception of the so-called 'pirate' radio in Zimbabwe. It specifically explores how the use of the Internet (and its associated ... Keywords: Convergence, Internet, Mobile phone, Oral tradition, Pirate radio, Reception, SMS, SW Radio Africa, Studio 7, Zimbabwe

Hayes Mawindi Mabweazara

2013-08-01T23:59:59.000Z

355

Plasma heating by an rf electric field  

SciTech Connect

In an analysis of the excitation of plasma waves by an electromagnetic wave at a frequency near the plasma frequency, the decay instabilities of first and second orders are taken into account. (AIP)

Musher, S.L.; Rubenchik, A.M.

1975-12-01T23:59:59.000Z

356

MODELING OF GYROSYNCHROTRON RADIO EMISSION PULSATIONS PRODUCED BY MAGNETOHYDRODYNAMIC LOOP OSCILLATIONS IN SOLAR FLARES  

Science Conference Proceedings (OSTI)

A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

2012-04-01T23:59:59.000Z

357

Radio detection of high-energy cosmic rays at the Pierre Auger Observatory  

E-Print Network (OSTI)

The southern Auger Observatory provides an excellent test bed to study the radio detection of extensive air showers as an alternative, cost-effective, and accurate tool for cosmic-ray physics. The data from the radio setup can be correlated with those from the well-calibrated baseline detectors of the Pierre Auger Observatory. Furthermore, human-induced radio noise levels at the southern Auger site are relatively low. We have started an R&D program to test various radio-detection concepts. Our studies will reveal Radio Frequency Interferences (RFI) caused by natural effects such as day-night variations, thunderstorms, and by human-made disturbances. These RFI studies are conducted to optimise detection parameters such as antenna design, frequency interval, antenna spacing and signal processing. The data from our initial setups, which presently consist of typically 3 - 4 antennas, will be used to characterise the shower from radio signals and to optimise the initial concepts. Furthermore, the operation of a large detection array requires autonomous detector stations. The current design is aiming at stations with antennas for two polarisations, solar power, wireless communication, and local trigger logic. The results of this initial phase will provide an important stepping stone for the design of a few tens kilometers square engineering array

A. M. van den Berg; for the Pierre Auger Collaboration

2007-08-13T23:59:59.000Z

358

TYPE III RADIO BURSTS PERTURBED BY WEAK CORONAL SHOCKS  

Science Conference Proceedings (OSTI)

Some type III bursts are observed to undergo sudden flux modifications, e.g., reductions and intensifications, when type III beams cross shocks in the upper corona or solar wind. First simulations are presented for type III bursts perturbed by weak coronal shocks, which type III beams traverse. The simulations incorporate spatially localized jumps in plasma density and electron and ion temperatures downstream of a shock. A shock is predicted to produce significant modulations to a type III burst: (1) a broadband flux reduction or frequency gap caused by the shock's density jump, (2) a narrowband flux intensification originating from where the downstream plasma density locally has a small gradient, (3) a possible intensification from the shock front or just upstream, and (4) changes in the frequency drift rate profile and the temporal evolution of radiation flux at frequencies corresponding to the shocked plasma. The modulations are caused primarily by fundamental modifications to the radiation processes in response to the shocked density and temperatures. The predicted intensifications and reductions appear qualitatively consistent with the available small number of reported observations, although it is unclear how representative these observations are. It is demonstrated that a weak shock can cause an otherwise radio-quiet type III beam to produce observable levels of narrowband radio emission. The simulations suggest that type III bursts with frequency-time fine structures may provide a tool to probe shocks in the corona and solar wind, especially for weak shocks that do not radiate by themselves.

Li, B.; Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia)

2012-07-10T23:59:59.000Z

359

Available Technologies: High Efficiency Spiral RF-Induction ...  

The spiral antennas efficient use of source geometry also ... Neutron and high energy gamma ... A typical RF-induction plasma generator with a ...

360

Influence of Substrate Temperature and RF Power on the Formation ...  

Science Conference Proceedings (OSTI)

Presentation Title, Influence of Substrate Temperature and RF Power on the Formation of ZnO Nanorods for Solar Driven Hydrogen Production. Author(s) ...

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Active high-power RF switch and pulse compression system  

DOE Patents (OSTI)

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.

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

1998-01-01T23:59:59.000Z

362

CLIC RF High Power Production Testing Program  

SciTech Connect

The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation. The testing program overview and test results available to date are presented.

Syratchev, I.; Riddone, G.; /CERN; Tantawi, S.G.; /SLAC

2011-11-02T23:59:59.000Z

363

Accelerator and rf system development for NLC  

Science Conference Proceedings (OSTI)

An experimental station for an X-band Next Linear Collider has been constructed at SLAC. This station consists of a klystron and modulator, a low-loss waveguide system for rf power distribution, a SLED II pulse-compression and peak-power multiplication system, acceleration sections and beam-line components (gun, prebuncher, preaccelerator, focussing elements and spectrometer). An extensive program of experiments to evaluate the performance of all components is underway. The station is described in detail in this paper, and results to date are presented.

Vlieks, A.E.; Callin, R.; Deruyter, H. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

1993-04-01T23:59:59.000Z

364

Gene Frequency  

NLE Websites -- All DOE Office Websites (Extended Search)

Gene Frequency Gene Frequency Name: donna Location: N/A Country: N/A Date: N/A Question: If six fingers is a dominant human trait why do we have only five? Replies: This is simple. There are just not many genes in the human population for six fingers. Steve Sample Look in any high school biology book for what is known as Hardy-Weinberg equilibrium. These two scientists (separately) said that gene frequencies do not change much unless something in the environment selects them over other genes. In other words, unless 6 fingers somehow becomes an advantage, and five-fingered people have less of an advantage, the frequency of six fingered people in the population will not necessarily increase. This is the same reason that recessive traits don't disappear from the population. Also, six fingers is not considered attractive and they may not get as many mates. Also, more people are born with six fingers than you might imagine but just have them amputated shortly after birth.

365

INITIATION AND DEVELOPMENT OF THE WHITE-LIGHT AND RADIO CORONAL MASS EJECTION ON 2001 APRIL 15  

SciTech Connect

The 2001 April 15 event was one of the largest of the last solar cycle. A former study established that this event was associated with a coronal mass ejection (CME) observed both at white light and radio frequencies. This radio CME is illuminated by synchrotron emission from relativistic electrons. In this paper, we investigate the relation of the radio CME to its extreme-ultraviolet (EUV) and white-light counterpart and reach four main conclusions. (1) The radio CME corresponds to the white-light flux rope cavity. (2) The presence of a reconnecting current sheet behind the erupting flux rope is framed, both from below and above, by bursty radio sources. This reconnection is the source of relativistic radiating electrons which are injected down along the reconnected coronal arches and up along the flux rope border forming the radio CME. (3) Radio imaging reveals an important lateral overexpansion in the low corona; this overexpansion is at the origin of compression regions where type II and III bursts are imaged. (4) Already in the initiation phase, radio images reveal large-scale interactions of the source active region (AR) with its surroundings, including another AR and open magnetic fields. Thus, these complementary radio, EUV, and white-light data validate the flux rope eruption model of CMEs.

Demoulin, P.; Pick, M.; Bouteille, A. [LESIA, UMR 8109 CNRS, UPMC, Universite Paris-Diderot, Observatoire de Paris-Meudon, Meudon 92195 (France); Vourlidas, A., E-mail: Pascal.Demoulin@obspm.fr [Space Sciences Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2012-05-10T23:59:59.000Z

366

Comparison between Poissonian and Markovian Primary Traffics in Cognitive Radio Networks  

E-Print Network (OSTI)

Cognitive Radio generates a big interest as a key cost-effective solution for the underutilization of frequency spectrum in legacy communication networks. The objective of this work lies in conducting a performance evaluation of the end-to-end message delivery under both Markovian and Poissonian primary traffics in lossy Cognitive Radio networks. We aim at inferring the most appropriate conditions for an efficient secondary service provision according to the Cognitive Radio network characteristics. Meanwhile, we have performed a general analysis for many still open issues in Cognitive Radio, but at the end only two critical aspects have been considered, namely, the unforeseen primary reclaims in addition to the collided cognitive transmissions due to the Opportunistic Spectrum Sharing. Some graphs, in view of the average Spectral Efficiency, have been computed and plotted to report some comparative results for a given video transmission under the Markovian and the Poissonian primary interruptions.

Chaoub, Abdelaali

2012-01-01T23:59:59.000Z

367

Radio astronomical imaging in the presence of strong radio interference  

E-Print Network (OSTI)

Abstract—Radio-astronomical observations are increasingly contaminated by interference, and suppression techniques become essential. A powerful candidate for interference mitigation is adaptive spatial filtering. We study the effect of spatial filtering techniques on radio-astronomical imaging. Current deconvolution procedures, such as CLEAN, are shown to be unsuitable for spatially filtered data, and the necessary corrections are derived. To that end, we reformulate the imaging (deconvolution/calibration) process as a sequential estimation of the locations of astronomical sources. This not only leads to an extended CLEAN algorithm, but also the formulation allows the insertion of other array signal processing techniques for direction finding and gives estimates of the expected image quality and the amount of interference suppression that can be achieved. Finally, a maximum-likelihood (ML) procedure for the imaging is derived, and an approximate ML image formation technique is proposed to overcome the computational burden involved. Some of the effects of the new algorithms are shown in simulated images. Index Terms—CLEAN, interference mitigation, maximum likelihood, minimum variance, parametric imaging, radio astronomy, spatial filtering, synthesis imaging. I.

Amir Leshem; Alle-jan Van Der Veen

2000-01-01T23:59:59.000Z

368

A RADIO-SELECTED SAMPLE OF GAMMA-RAY BURST AFTERGLOWS  

SciTech Connect

We present a catalog of radio afterglow observations of gamma-ray bursts (GRBs) over a 14 year period from 1997 to 2011. Our sample of 304 afterglows consists of 2995 flux density measurements (including upper limits) at frequencies between 0.6 GHz and 660 GHz, with the majority of data taken at 8.5 GHz frequency band (1539 measurements). We use this data set to carry out a statistical analysis of the radio-selected sample. The detection rate of radio afterglows has stayed unchanged almost at 31% before and after the launch of the Swift satellite. The canonical long-duration GRB radio light curve at 8.5 GHz peaks at three to six days in the source rest frame, with a median peak luminosity of 10{sup 31} erg s{sup -1} Hz{sup -1}. The peak radio luminosities for short-hard bursts, X-ray flashes, and the supernova-GRB classes are an order of magnitude or more fainter than this value. There are clear relationships between the detectability of a radio afterglow and the fluence or energy of a GRB, and the X-ray or optical brightness of the afterglow. However, we find few significant correlations between these same GRB and afterglow properties and the peak radio flux density. We also produce synthetic light curves at centimeter and millimeter bands using a range of blast wave and microphysics parameters derived from multiwavelength afterglow modeling, and we use them to compare to the radio sample. Finding agreement, we extrapolate this behavior to predict the centimeter and millimeter behavior of GRBs observed by the Expanded Very Large Array and the Atacama Large Millimeter Array.

Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7M3C9 (Canada); Frail, Dale A., E-mail: Poonam.Chandra@rmc.ca [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

2012-02-20T23:59:59.000Z

369

Fermilab Tevatron high level rf accelerating systems  

SciTech Connect

Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer.

Kerns, Q.; Kerns, C.; Miller, H.; Tawser, S.; Reid, J.; Webber, R.; Wildman, D.

1985-06-01T23:59:59.000Z

370

Random Subcarrier Allocation in OFDM-Based Cognitive Radio Networks and Hyper Fading Channels  

E-Print Network (OSTI)

Advances in communications technologies entail demands for higher data rates. One of the popular solutions to fulfill this requirement was to allocate additional bandwidth, which unfortunately is not anymore viable due to spectrum scarcity. In addition, spectrum measurements around the globe have revealed the fact that the available spectrum is under-utilized. One of the most remarkable solutions to cope with the under-utilization of radio-frequency (RF) spectrum is the concept of cognitive radio (CR) with spectrum sharing features, also referred to as spectrum sharing systems. In CR systems, the main implementation issue is spectrum sensing because of the uncertainties in propagation channel, hidden primary user (PU) problem, sensing duration and security issues. Hence, the accuracy and reliability of the spectrum sensing information may inherently be suspicious and questionable. Due to the imprecise spectrum sensing information, this dissertation investigates the performance of an orthogonal frequency-division multiplexing (OFDM)-based CR spectrum sharing communication system that assumes random allocation and absence of the PU's channel occupation information, i.e., no spectrum sensing is employed to acquire information about the availability of unused subcarriers or the PU's activity. In addition, no cooperation occurs between the transmitters of the PUs and secondary users (SUs). The main benefit of random subcarrier utilization is to uniformly distribute the amount of SUs' interference among the PUs' subcarriers, which can be termed as interference spreading. The analysis and performance of such a communication set-up provides useful insights and can be utilized as a valid benchmark for performance comparison studies in CR spectrum sharing systems that assume the availability of spectrum sensing information. In the first part this dissertation, due to the lack of information about PUs' activities, the SU randomly allocates the subcarriers of the primary network and collide with the PUs' subcarriers with a certain probability. The average capacity of SU with subcarrier collisions is employed as performance measure to investigate the proposed random allocation scheme for both general and Rayleigh channel fading models. In the presence of multiple SUs, the multiuser diversity gain of SUs is also investigated. To avoid the subcarrier collisions at the SUs due to the random allocation scheme and to obtain the maximum sum rate for SUs based on the available subcarriers, an efficient centralized sequential algorithm based on the opportunistic scheduling and random allocation (utilization) methods is proposed to ensure the orthogonality of assigned subcarriers. In the second part of this dissertation, in addition to the collisions between the SUs and PUs, the inter-cell collisions among the subcarriers of SUs (belonging to different cells) are assumed to occur due to the inherent nature of random access scheme. A stochastic analysis of the number of subcarrier collisions between the SUs' and PU's subcarriers assuming fixed and random number of subcarriers requirements for each user is conducted. The performance of the random scheme in terms of capacity and capacity (rate) loss caused by the subcarrier collisions is investigated by assuming an interference power constraint at PU to protect its operation. Lastly, a theoretical channel fading model, termed hyper fading channel model, that is suitable to the dynamic nature of CR channel is proposed and analyzed. To perform a general analysis, the achievable average capacity of CR spectrum sharing systems over the proposed dynamic fading environments is studied.

Ekin, Sabit 1981-

2012-12-01T23:59:59.000Z

371

Explanation of persistent high frequency density structure in coalesced bunches  

SciTech Connect

It has been observed that after the Main Ring rf manipulation of coalescing (where 5 to 13 primary bunches are transferred into a single rf bucket) the new secondary bunch displays evidence of high frequency density structure superimposed on the approximately Gaussian longitudinal bunch length distribution. This structure is persistent over a period of many seconds (hundreds of synchrotron oscillation periods). With the help of multiparticle simulation programs, an explanation of this phenomenon is given in terms of single particle longitudinal phase space dynamics. No coherent effects need be taken into account. 6 refs., 10 figs.

Jackson, Gerald P.

1988-07-01T23:59:59.000Z

372

3-2 Instrument Development Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

the IDL's most recognizable expertise and capabilities fall into the following areas: * high-voltage expertise * radio frequency (RF) expertise * high-speed analog and digital...

373

The Klynac: An Integrated Klystron and Linear Accelerator  

SciTech Connect

The Klynac concept integrates an electron gun, a radio frequency (RF) power source, and a coupled-cavity linear accelerator into a single resonant system

Potter, J. M., Schwellenbach, D., Meidinger, A.

2012-08-07T23:59:59.000Z

374

Security Standards for the RFID Market  

Science Conference Proceedings (OSTI)

... tags con- tinue to decrease in price while offer ... mobile tires, and packaging for household items. ... captures the radio frequency (RF) energy from the ...

2007-10-26T23:59:59.000Z

375

A data link layer in support of swarming of autonomous underwater vehicles.  

E-Print Network (OSTI)

??Communication underwater is challenging because of the inherent characteristics of the media. First, common radio frequency (RF) signals utilized in wireless communications cannot be used… (more)

Jabba Molinares, Daladier

2009-01-01T23:59:59.000Z

376

DO RADIO MAGNETARS PSR J1550-5418 AND J1622-4950 HAVE GIGAHERTZ-PEAKED SPECTRA?  

Science Conference Proceedings (OSTI)

We study the radio spectra of two magnetars, PSR J1550-5418 and J1622-4950. We argue that they are good candidates for pulsars with gigahertz-peaked spectra (GPS), as their observed flux density decreases at frequencies below 7 GHz. We suggest that this behavior is due to the influence of the pulsars' environments on radio waves. Both of the magnetars are associated with supernova remnants and thus are surrounded by hot, ionized gas, which can be responsible for the free-free absorption of radio waves. We conclude that the GPS feature of both magnetars and typical pulsars are formed by similar processes in the surrounding media rather than by different radio-emission mechanisms. Thus, the radio magnetars PSR J1550-5418 and J1622-4950 can be included in the class of GPS pulsars.

Kijak, J.; Tarczewski, L.; Lewandowski, W. [Kepler Institute of Astronomy, University of Zielona Gora, Lubuska 2, 65-265 Zielona Gora (Poland); Melikidze, G., E-mail: jkijak@astro.ia.uz.zgora.pl [Also at Abastumani Astrophysical Observatory, Ilia State University, 3-5 Cholokashvili Avenue, Tbilisi 0160, Georgia. (Georgia)

2013-07-20T23:59:59.000Z

377

RF Power Degradation of GaN High Electron Mobility Transistors  

E-Print Network (OSTI)

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 ...

Joh, Jungwoo

378

Progress on the RF Coupling Coil Module Design for the MICE Channel  

E-Print Network (OSTI)

Spallation Neutron Source (SNS) type ceramic RF windows arecouplers together with the SNS-type ceramic RF window. Ahigh power tested now at the SNS RF test lab. Cavity length

2005-01-01T23:59:59.000Z

379

Booster Synchrotron RF System Upgrade for SPEAR3  

Science Conference Proceedings (OSTI)

Recent progress at the SPEAR3 includes the increase in stored current from 100 mA to 200 mA and top-off injection to allow beamlines to stay open during injection. Presently the booster injects 3.0 GeV beam to SPEAR3 three times a day. The stored beam decays to about 150 mA between the injections. The growing user demands are to increase the stored current to the design value of 500 mA, and to maintain it at a constant value within a percent or so. To achieve this goal the booster must inject once every few minutes. For improved injection efficiency, all RF systems at the linac, booster and SPEAR3 need to be phase-locked. The present booster RF system is basically a copy of the SPEAR2 RF system with 358.5 MHz and 40 kW peak RF power driving a 5-cell RF cavity for 1.0 MV gap voltage. These requirements entail a booster RF system upgrade to a scaled down version of the SPEAR3 RF system of 476.3 MHz with 1.2 MW cw klystron output power capabilities. We will analyze each subsystem option for their merits within budgetary and geometric space constraints. A substantial portion of the system will come from the decommissioned PEP-II RF stations.

Park, Sanghyun; /SLAC; Corbett, Jeff; /SLAC

2012-07-06T23:59:59.000Z

380

Self-homodyne RF-optical microdisk receiver  

E-Print Network (OSTI)

modulation with optical transfer function (Po VRF 2 ) Self-homodyne RF-photonic receiver f ip Nonlinear and nonlinear modulation Transmittedoptical power t Wavelength t t Linear (Po VRF) Nonlinear (Po VRF 2) VRF ),,,,,( , 0 2 0 2 2 tPQGf dV Pd N EinoV VRF RF == = Microdisk optical mixer (laser= res) GV : voltage gain Q

Levi, Anthony F. J.

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


381

ITO Thin Films by RF Sputtering for Ethanol Sensing  

Science Conference Proceedings (OSTI)

The sensor for detection of ethanol vapours using RF sputter deposited ITO thin film on glass and Si substrates is reported. The principle of operation is the change of resistance of ITO film on exposure to ethanol vapours. The films were annealed at ... Keywords: Indium Tin Oxide, RF sputtering, ethanol sensor

Sudhir Chandra; H. J. Pandya; A. L. Vyas

2010-07-01T23:59:59.000Z

382

A high-power L-band RF window  

E-Print Network (OSTI)

June. 2001. [3] "700 MHz Window R&D at LBNL", R. Rimmer et.Testing of PEP-II RF Cavity Windows", M. Neubauer et. al. ,A HIGH-POWER L-BAND RF WINDOW* R.A. Rimmer † , G. Koehler,

2001-01-01T23:59:59.000Z

383

RF-MEMS capacitive switches with high reliability  

DOE Patents (OSTI)

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.

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

384

The Triggering and Bias of Radio Galaxies  

E-Print Network (OSTI)

We present new results on the clustering and three-dimensional distribution of radio galaxies from the Texas-Oxford NVSS Structure (TONS) survey. The TONS survey was constructed to look at the distribution of radio galaxies in a region of moderate (0 3 mJy) radio galaxies over large areas on the sky. We find that redshift spikes, which represent large concentrations of radio galaxies which trace (~ 100 Mpc^3) super-structures are a common phenomena in these surveys. Under the assumption of quasi-linear structure formation theory and a canonical radio galaxy bias, the structures represent ~ 4-5 sigma peaks in the primordial density field and their expected number is low. The most plausible explanation for these low probabilities is an increase in the radio galaxy bias with redshift. To investigate potential mechanisms which have triggered the radio activity in these galaxies - and hence may account for an increase in the bias of this population, we performed imaging studies of the cluster environment of the radio galaxies in super-structure regions. Preliminary results show that these radio galaxies may reside preferentially at the edges of rich clusters. If radio galaxies are preferentially triggered as they fall towards rich clusters then they would effectively adopt the cluster bias.

Kate Brand; Steve Rawlings; Joe Tufts; Gary Hill

2004-03-16T23:59:59.000Z

385

Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations  

E-Print Network (OSTI)

Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves ...

Jaeger, E. F.

386

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

DOE Patents (OSTI)

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

Praeg, W.F.

1982-03-09T23:59:59.000Z

387

Proposal for high pressure RF cavity test in the MTA  

DOE Green Energy (OSTI)

In order to demonstrate the feasibility of high pressure hydrogen gas filled RF (HPRF) cavities for muon ionization cooling, an HPRF cavity must be tested with a high intensity charged beam. When an HPRF cavity is irradiated with an intense beam each incident particle generates about 1000 electrons and ions per cubic centimeter in a high pressure cavity via ionization. These ionization electrons are influenced by the RF field and the RF quality factor goes down. This Q factor reduction will be a problem with a multi bunch beam, e.g., a muon beam for a muon collider consists of a 12 to 20 bunch train beam with 5 ns timing gap. Thus, the RF field must recover in few nano seconds. We propose to use a 400 MeV proton beam in the MTA and measure a beam loading effect in the HPRF cavity and study the recovery mechanism of the RF field.

Yonehara, K.; /Fermilab

2010-09-01T23:59:59.000Z

388

Cold Test Measurements on the GTF Prototype RF Gun  

Science Conference Proceedings (OSTI)

The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. Based on longitudinal phase space measurements showing a correlated energy spread the gun was removed and re-characterized in 2002. The low power RF measurements performed on the gun are described below. Perturbative bead measurements were performed to determine the field ratio in the two-cell gun, and network analyzer measurements were made to characterize the mode structure. A second probe was installed to monitor the RF field in the first cell, and a diagnostic was developed to monitor the high-power field ratio. Calibration of the RF probes, a model for analyzing RF measurements, and Superfish simulations of bead and RF measurements are described.

Gierman, S.M.

2010-12-03T23:59:59.000Z

389

Anomalous Quantum Interference Induced by Landau-Zener Transitions in a Strongly Driven rf-SQUID Qubit  

E-Print Network (OSTI)

We irradiated an rf-SQUID qubit with large-amplitude and high frequency electromagnetic field. Population transitions between macroscopic distinctive quantum states due to Landau-Zener transitions at energy-level avoided crossings were observed. The qubit population on the excited states as a function of flux detuning and microwave power exhibits interference patterns. Some novel features are found in the interference and a model based on rate equations can well address the features.

Wang, Yiwen; Wen, Xueda; Pan, Cheng; Sun, Guozhu; Chen, Jian; Kang, Lin; Xu, Weiwei; Yu, Yang; Wu, Peiheng

2009-01-01T23:59:59.000Z

390

Optimal monitoring in multi-channel multi-radio wireless mesh networks  

Science Conference Proceedings (OSTI)

Wireless mesh networks (WMN) are finding increasing usage in city-wide deployments for providing network connectivity. Mesh routers in WMNs typically use multiple wireless channels to enhance the spatial-reuse of frequency bands, often with multiple ... Keywords: approximation algorithm, lp rounding, multi-channel multi-radio wireless networks, security monitoring, wireless mesh networks

Dong-Hoon Shin; Saurabh Bagchi

2009-05-01T23:59:59.000Z

391

Parallel radio-wave propagation modeling with image-based ray tracing techniques  

Science Conference Proceedings (OSTI)

Ray tracing is a technique based on the numerical simulation of geometrical optics and the uniform theory of diffraction, two well-known approximate methods for estimating a high-frequency electromagnetic field, based on the ray theory of field propagation. ... Keywords: Load balancing, Message passing interface, Performance evaluation, Radio-wave propagation, Ray tracing, Wireless communications

T. E. Athanaileas; G. E. Athanasiadou; G. V. Tsoulos; D. I. Kaklamani

2010-12-01T23:59:59.000Z

392

A 610-MHz Galactic Plane Pulsar Search with the Giant Meterwave Radio Telescope  

E-Print Network (OSTI)

We report on the discovery of three new pulsars in the first blind survey of the north Galactic plane (45 < l < 135 ; |b| < 1) with the Giant Meterwave Radio telescope (GMRT) at an intermediate frequency of 610 MHz. The timing parameters, obtained in follow up observations with the Lovell Telescope at Jodrell Bank Observatory and the GMRT, are presented.

B. C. Joshi; M. A. McLaughlin; M. Kramer; A. G. Lyne; D. R. Lorimer; D. A. Ludovici; M. Davies; A. J. Faulkner

2007-10-16T23:59:59.000Z

393

Automated Hydroforming of Seamless Superconducting RF Cavity  

SciTech Connect

We are studying the possibility of automated hydroforming process for seamless superconducting RF cavities. Preliminary hydroforming tests of three-cell cavities from seamless tubes made of C1020 copper have been performed. The key point of an automated forming is to monitor and strictly control some parameters such as operation time, internal pressure and material displacements. Especially, it is necessary for our studies to be able to control axial and radial deformation independently. We plan to perform the forming in two stages to increase the reliability of successful forming. In the first stage hydroforming by using intermediate constraint dies, three-cell cavities were successfully formed in less than 1 minute. In parallel, we did elongation tests on cavity-quality niobium and confirmed that it is possible to achieve an elongation of >64% in 2 stages that is required for our forming of 1.3 GHz cavities.

Nagata, Tomohiko [ULVAC, Inc.; Shinozawa, Seiichi [ULVAC, Inc.; Abe, Noriyuki [ULVAC, Inc.; Nagakubo, Junki [ULVAC, Inc.; Murakami, Hirohiko [ULVAC, Inc.; Tajima, Tsuyoshi [Los Alamos National Laboratory; Inoue, Hitoshi [High Energy Accelerator Research Organization, KEK; Yamanaka, Masashi [High Energy Accelerator Research Organization, KEK; Ueno, Kenji [High Energy Accelerator Research Organization, KEK

2012-07-31T23:59:59.000Z

394

Fast thermometry for superconducting rf cavity testing  

SciTech Connect

Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity.

Orris, Darryl; Bellantoni, Leo; Carcagno, Ruben H.; Edwards, Helen; Harms, Elvin Robert; Khabiboulline, Timergali N.; Kotelnikov, Sergey; Makulski, Andrzej; Nehring, Roger; Pischalnikov, Yuriy; /Fermilab

2007-06-01T23:59:59.000Z

395

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process  

SciTech Connect

Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrate and is fabricated by Peregrine Semiconductor corporation. This thesis work details the design of the Voltage Controlled Oscillator (VCO) portion of the PLL frequency synthesizer and constitutes an fully integrated VCO core circuit and a high-isolation buffer amplifier. The high-isolation buffer amplifier was designed to provide 16 dB of gain for 2200-3495 MHz as well as 60 dB of isolation for the oscillator core to provide immunity to frequency pulling due to RF load mismatch. Actual measurements of the amplifier gain and isolation showed the gain was approximately 5 dB lower than the simulated gain when all bond-wire and test substrate parasitics were taken into account. The isolation measurements were shown to be 28 dB at the high end of the frequency band but the measurement was more than likely compromised due to the aforementioned bond-wire and test substrate parasitics. The S-band oscillator discussed in this work was designed to operate over a frequency range of 2200 to 2300 MHz with a minimum output power of 0 dBm with a phase-noise of -92 dBc/Hz at a 100 kHz offset from the carrier. The tuning range was measured to be from 2215 MHz to 2330 MHz with a minimum output power of -7 dBm over the measured frequency range. A phase-noise of -90 dBc was measured at a 100 kHz offset from the carrier.

Garrison, Sean

2009-05-21T23:59:59.000Z

396

Available Technologies: Nanotube Radio for Communications and ...  

APPLICATIONS OF TECHNOLOGY: All-in-one radio receiver for cell phones/wireless networks/GPS and other electronic devices

397

NIST Radio Station WWV Broadcast Format  

Science Conference Proceedings (OSTI)

... 2, Space Weather for the past 24 hours has been severe. Solar radiation storm(s) reaching the S4 level is in progress. Radio ...

2011-12-22T23:59:59.000Z

398

NIST Radio Stations WWV/WWVH  

Science Conference Proceedings (OSTI)

... 2, Space Weather for the past 24 hours has been severe. Solar radiation storm(s) reaching the S4 level is in progress. Radio ...

2010-10-05T23:59:59.000Z

399

Survey on solar X-ray flares and associated coherent radio emissions  

E-Print Network (OSTI)

The radio emission during 201 X-ray selected solar flares was surveyed from 100 MHz to 4 GHz with the Phoenix-2 spectrometer of ETH Zurich. The selection includes all RHESSI flares larger than C5.0 jointly observed from launch until June 30, 2003. Detailed association rates of radio emission during X-ray flares are reported. In the decimeter wavelength range, type III bursts and the genuinely decimetric emissions (pulsations, continua, and narrowband spikes) were found equally frequently. Both occur predominantly in the peak phase of hard X-ray (HXR) emission, but are less in tune with HXRs than the high-frequency continuum exceeding 4 GHz, attributed to gyrosynchrotron radiation. In 10% of the HXR flares, an intense radiation of the above genuine decimetric types followed in the decay phase or later. Classic meter-wave type III bursts are associated in 33% of all HXR flares, but only in 4% they are the exclusive radio emission. Noise storms were the only radio emission in 5% of the HXR flares, some of them with extended duration. Despite the spatial association (same active region), the noise storm variations are found to be only loosely correlated in time with the X-ray flux. In a surprising 17% of the HXR flares, no coherent radio emission was found in the extremely broad band surveyed. The association but loose correlation between HXR and coherent radio emission is interpreted by multiple reconnection sites connected by common field lines.

Arnold O. Benz; Paolo Grigis; Andre Csillagy; Pascal Saint-Hilaire

2004-10-19T23:59:59.000Z

400

A Search for the Radio Counterpart to the March 1, 1994 Gamma Ray Burst  

E-Print Network (OSTI)

We report on the results of a search for the radio counterpart to the bright gamma-ray burst of March 1, 1994. Using the Dominion Radio Astrophysical Observatory Synthesis Telescope sensitive, wide-field radio images at 1.4 GHz and 0.4 GHz were made of a region around GRB940301. A total of 15 separate radio images were obtained at each frequency, sampling a near-continuous range of post-burst timescales between 3 and 15 days, as well as 26, 47 and 99 days. We place an upper limit of 3.5 mJy on a fading/flaring radio counterpart at 1.4 GHz and 55 mJy at 0.4 GHz. Previous searches have concentrated on searching for a counterpart at only one epoch following the outburst. In contrast, the present search maintains high sensitivity over two decades of post-burst time durations. Time-variable radio emission after the initial gamma-ray burst is a prediction of all fireball models, currently the most popular model for gamma-ray bursts. Our observations allow us to put significant constraints on the fireball parameters for cosmological models of gamma-ray bursts.

Frail; Kulkarni; Hurley; Fishman; Kouveliotou; Meegan; Sommer; Boer; Niel; Cline

1994-09-12T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations  

E-Print Network (OSTI)

The commonly used classical equipartition or minimum-energy estimate of total magnetic fields strengths from radio synchrotron intensities is of limited practical use because it is based on the hardly known ratio K of the total energies of cosmic ray protons and electrons and also has inherent problems. We present a revised formula, using the number density ratio K for which we give estimates. For particle acceleration in strong shocks K is about 40 and increases with decreasing shock strength. Our revised estimate for the field strength gives larger values than the classical estimate for flat radio spectra with spectral indices of about 0.5-0.6, but smaller values for steep spectra and total fields stronger than about 10 muG. In very young supernova remnants, for example, the classical estimate may be too large by up to 10x. On the other hand, if energy losses of cosmic ray electrons are important, K increases with particle energy and the equipartition field may be underestimated significantly. Our revised larger equipartition estimates in galaxy clusters and radio lobes are consistent with independent estimates from Faraday rotation measures, while estimates from the ratio between radio synchrotron and X-ray inverse Compton intensities generally give much weaker fields. This may be explained e.g. by a concentration of the field in filaments. Our revised field strengths may also lead to major revisions of electron lifetimes in jets and radio lobes estimated from the synchrotron break frequency in the radio spectrum.

Rainer Beck; Marita Krause

2005-07-15T23:59:59.000Z

402

High-resolution radio observations of submillimetre galaxies  

E-Print Network (OSTI)

We have produced sensitive, high-resolution radio maps of 12 SMGs in the Lockman Hole using combined MERLIN and VLA data at a frequency of 1.4 GHz. Integrating for 350hr yielded an r.m.s. noise of 6.0 uJy/beam and a resolution of 0.2-0.5". For the first time, wide-field data from the two arrays have been combined in the (u,v) plane and the bandwidth smearing response of the VLA data has been removed. All of the SMGs are detected in our maps as well as sources comprising a non-submm luminous control sample. We find evidence that SMGs are more extended than the general uJy radio population and that therefore, unlike in local ULIRGs, the starburst component of the radio emission is extended and not confined to the galactic nucleus. For the eight sources with redshifts we measure linear sizes between 1 and 8 kpc with a median of 5 kpc. Therefore, they are in general larger than local ULIRGs which may support an early-stage merger scenario for the starburst trigger. X-rays betray AGN in six of the 33 sources in the combined sample. All but one of these are in the control sample, suggesting a lower incidence of AGN amongst the submm-luminous galaxies which is, in turn, consistent with increased X-ray absorption in these dust-obscured starbursts. Only one of our sources is resolved into multiple, distinct components with our high-resolution data. Finally, compared to a previous study of faint radio sources in the GOODS-N field we find systematically smaller source sizes and no evidence for a tail extending to ~4". Possible reasons for this are discussed.

A. D. Biggs; R. J. Ivison

2007-12-18T23:59:59.000Z

403

Plasma rotation and rf heating in DIII-D  

SciTech Connect

In a variety of discharge conditions on DIII-D it is observed that rf electron heating reduces the toroidal rotation speed and core ion temperature. The rf heating can be with either fast wave or electron cyclotron heating and this effect is insensitive to the details of the launched toroidal wavenumber spectrum. To date all target discharges have rotation first established with co-directed neutral beam injection. A possible cause is enhanced ion momentum and thermal diffusivity due to electron heating effectively creating greater anomalous viscosity. Another is that a counter directed toroidal force is applied to the bulk plasma via rf driven radial current.

deGrassie, J.S.; Baker, D.R.; Burrell, K.H. [General Atomics, San Diego, CA (United States)] [and others

1999-05-01T23:59:59.000Z

404

Post-outburst radio observation of the region around McNeil's nebula (V1647 Ori)  

E-Print Network (OSTI)

We present post-outburst (~ 100 days after outburst) radio continuum observation of the region (~ 30' x 30') around McNeil's nebula (V1647 Orionis). The observations were carried out using the Giant Metrewave Radio Telescope (GMRT), India, at 1272 MHz on 2004 Feb 14.5 UT. Although 8 sources have been detected within a circular diameter of 25' centred on V1647 Ori, we did not detect any radio continuum emission from McNeil's nebula. We assign a 5-sigma upper limit of 0.15 mJy/beam for V1647 Ori where the beam size is 5.6" x 2.7". Even at higher frequencies of 4.9 and 8.5 GHz (VLA archival data), no radio emission has been detected from this region. Three scenarios namely, emission from homogeneous HII region, ionised stellar wind and shock ionised gas, are explored in the light of our GMRT upper-limit. For the case of homogeneous HII region, the radius of the emitting region is constrained to be ~ 2,500 K, which is consistent with the reported radio and H-alpha emission. In the ionised stellar wind picture, our upper limit of radio emission translates to the ratio of mass loss rate and terminal velocity, (M_dot/v_infinity) wind shocks the dense neutral (molecular) cloud, the radio upper limit implies that the fraction of the wind encountering the dense obstacle is ~ 7.2 x 10^7 cm^(-3) of the radio emitting plasma have been constrained using a two phase medium in pressure equilibrium for a volume filling factor of 0.9.

S. Vig; S. K. Ghosh; V. K. Kulkarni; D. K. Ojha

2005-10-15T23:59:59.000Z

405

The depolarisation properties of powerful extragalactic radio sources as a function of cosmic epoch  

E-Print Network (OSTI)

We use the observed polarisation properties of a sample of 26 powerful radio galaxies and radio-loud quasars to constrain the conditions in the Faraday screens local to the sources. We adopt the cosmological redshift, low-frequency radio luminosity and physical size of the large-scale radio structures as our `fundamental' parameters. We find no correlation of the radio spectral index with any of the fundamental parameters. The observed rotation measure is also independent of these parameters. The difference between the rotation measures of the two lobes of an individual source as well as the dispersion of the rotation measure show significant correlations with the source redshift, but not with the radio luminosity or source size. Thus the small-scale structure observed in the rotation measure is caused by a Faraday screen local to the sources. The observed asymmetries between the lobes of our sources show no significant trends with each other or other source properties. Finally, we show that the commonly used model for the depolarisation of synchrotron radio emission by foreground Faraday screens is inconsistent with our observations. We apply alternative models to our data and show that they require a strong increase of the dispersion of the rotation measure inside the Faraday screens with cosmological redshift. Correcting our observations with these models for redshift effects, we find a strong correlation of the depolarisation measure with redshift and a significantly weaker correlation with radio luminosity. All our results are consistent with a decrease in the order of the magnetic field structure of the Faraday screen local to the sources for increasing cosmological redshift. (abridged)

J. A. Goodlet; C. R. Kaiser

2005-03-08T23:59:59.000Z

406

Graphene-Based Ambipolar RF Mixers  

E-Print Network (OSTI)

The combination of the unique properties of graphene with new device concepts and nanotechnology can overcome some of the main limitations of traditional electronics in terms of maximum frequency, linearity, and power ...

Wang, Han

407

A high sensitivity ultralow temperature RF conductance and noise measurement setup  

SciTech Connect

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies.

Parmentier, F. D.; Mahe, A.; Denis, A.; Berroir, J.-M.; Glattli, D. C.; Placais, B.; Feve, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS UMR 8551, Universite P. et M. Curie, Universite D. Diderot 24, rue Lhomond, 75231 Paris Cedex 05 (France)

2011-01-15T23:59:59.000Z

408

The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems  

SciTech Connect

In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

Guo, Jiquan; /SLAC

2009-03-20T23:59:59.000Z

409

New radio observations of QSO 0957+561 confirm optical-to radio time delay  

E-Print Network (OSTI)

In our previous publications have been reported about possible time delay between optical and radio (6 cm) variations in QSO 0957+561 and noted that the result can be tested with new radio observations. Here we have made this test using new published (Haarasma et al., 1999) radio observations of the object in 6 cm and 4 cm. We have found that the new observations confirm optical-to-radio time delay. Additionally we have found that radio 6 cm variations followed 4 cm ones with time delay about 230 days. Obtained results imply existence of the variable beamed hard radiation in the nucleus of the QSO.

V. L. Oknyanskij

2005-02-02T23:59:59.000Z

410

CONSTRAINING THE VELA PULSAR'S RADIO EMISSION REGION USING NYQUIST-LIMITED SCINTILLATION STATISTICS  

SciTech Connect

Using a novel technique, we achieve {approx}100 picoarcsec resolution and set an upper bound of less than 4 km for the characteristic size of the Vela pulsar's emission region. Specifically, we analyze flux-density statistics of the Vela pulsar at 760 MHz. Because the pulsar exhibits strong diffractive scintillation, these statistics convey information about the spatial extent of the radio emission region. We measure both a characteristic size of the emission region and the emission sizes for individual pulses. Our results imply that the radio emission altitude for the Vela pulsar at this frequency is less than 340 km.

Johnson, M. D.; Gwinn, C. R. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Demorest, P., E-mail: michaeltdh@physics.ucsb.edu, E-mail: cgwinn@physics.ucsb.edu, E-mail: pdemores@nrao.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22093 (United States)

2012-10-10T23:59:59.000Z

411

The new amateur radio university network: AMUNET  

Science Conference Proceedings (OSTI)

The intention of this paper is to give the readers an opportunity to become familiar with nonofficial and often ad-hoc constructed, computerized amateur radio networks, that might be easily used as AMUNETs - the digital links between university centers, ... Keywords: ADL, AMUNET, amateur radio, communication, computer, education, rural area, university

Miroslav Skoric

2005-07-01T23:59:59.000Z

412

Review: Cognitive radio network security: A survey  

Science Conference Proceedings (OSTI)

Recent advancements in wireless communication are creating a spectrum shortage problem on a daily basis. Recently, Cognitive Radio (CR), a novel technology, has attempted to minimize this problem by dynamically using the free spectrum in wireless communications ... Keywords: Attacks, Primary users, Radio, Secondary users, Security, Trust

Sazia Parvin; Farookh Khadeer Hussain; Omar Khadeer Hussain; Song Han; Biming Tian; Elizabeth Chang

2012-11-01T23:59:59.000Z

413

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)  

E-Print Network (OSTI)

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)

Grelick, A E; Arnold, N; White, M

1996-01-01T23:59:59.000Z

414

RF Micro Devices Inc RFMD | Open Energy Information  

Open Energy Info (EERE)

RF Micro Devices Inc RFMD RF Micro Devices Inc RFMD Jump to: navigation, search Name RF Micro Devices, Inc. (RFMD) Place Greensboro, North Carolina Zip 27409-9421 Product RF Micro Devices, Inc. is a global leader in the design and manufacture of high-performance semiconductor components. Coordinates 44.576059°, -72.294016° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":44.576059,"lon":-72.294016,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

415

Rf system for the NSLS coherent infrared radiation source  

Science Conference Proceedings (OSTI)

The existing NSLS X-ray Lithography Source (XLS Phase I) is being considered for a coherent synchrotron radiation source. The existing 211 MHz warm cavity will be replaced with a 5-cell 2856 MHz superconducting RF cavity, driven by a series of 2 kW klystrons. The RF system will provide a total V{sub RF} of 1.5 MV to produce {sigma}{sub L} = 0.3 mm electron bunches at an energy of 150 MeV. Superconducting technology significantly reduces the required space and power needed to achieve the higher voltage. It is the purpose of this paper to describe the superconducting RF system and cavity, power requirements, and cavity design parameters such as input coupling, Quality Factor, and Higher Order Modes.

Broome, W.; Biscardi, R.; Keane, J.; Mortazavi, P.; Thomas, M.; Wang, J.M.

1995-05-01T23:59:59.000Z

416

Efficiency enhancement techniques for RF and millimeter wave power amplifiers  

E-Print Network (OSTI)

Power amplifiers are the circuit blocks in wireless transceivers that require the largest power budget because of their relatively low efficiencies. RF designers cannot depend solely on the development better semiconductor ...

Ogunnika, Olumuyiwa Temitope, 1978-

2012-01-01T23:59:59.000Z

417

Channel engineering of SOI MOSFETs for RF applications  

E-Print Network (OSTI)

Channel engineering of SOI MOSFETs is explored by altering ion implantation without adding any new fabrication steps to the standard CMOS process. The effects of implantation on characteristics important for RF applications, ...

Keast, Craig L.

418

An improved RF cavity search for halo axions  

E-Print Network (OSTI)

The axion is a hypothetical elementary particle and cold dark matter candidate. In this RF cavity experiment, halo axions entering a resonant cavity immersed in a static magnetic field convert into microwave photons, with ...

Yu, D. B. (Daniel Byungyoon), 1976-

2004-01-01T23:59:59.000Z

419

Hom dampers for ALS storage ring RF cavities  

E-Print Network (OSTI)

of the HOM dampers on ALS rf cavities was an immediatesuccess. Now, the ALS storage ring can operate with the 312The cross-section of the ALS third harmonic cavity with two

2003-01-01T23:59:59.000Z

420

Electrodeless lighting RF power source development. Final report  

SciTech Connect

An efficient, solid state RF power source has been developed on this NICE project for exciting low power electrodeless lamp bulbs. This project takes full advantage of concurrent advances in electrodeless lamp technology. Electrodeless lamp lighting systems utilizing the sulfur based bulb type developed by Fusion Lighting, Inc., is an emerging technology which is based on generating light in a confined plasma created and sustained by RF excitation. The bulb for such a lamp is filled with a particular element and inert gas at low pressure when cold. RF power from the RF source creates a plasma within the bulb which reaches temperatures approaching those of high pressure discharge lamp plasmas. At these temperatures the plasma radiates substantial visible light with a spectrum similar to sunlight.

NONE

1996-08-30T23:59:59.000Z

Note: This page contains sample records for the topic "rf radio frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

A Test and Diagnosis Methodology for RF Transceivers  

Science Conference Proceedings (OSTI)

This paper proposes an RF test and diagnosis methodology based on digital DFT structure and builtin DSP function of a SoC Chip. Constellation variation plots are proposed to identify the faulty component. Furthermore, linear interpolation is used to ...

Hung-kai Chen; Chauchin Su

2007-10-01T23:59:59.000Z

422

Test estructural i predictiu per a circuits RF CMOS.  

E-Print Network (OSTI)

??En aquesta tesi s'ha desenvolupat una tècnica de test que permet testar un LNA i un mesclador, situats en el capçal RF d'un receptor CMOS,… (more)

Suenaga Portugués, Kay

2008-01-01T23:59:59.000Z

423

BN/Graphene/BN Transistors for RF Applications  

E-Print Network (OSTI)

In this letter, we demonstrate the first BN/graphene/BN field-effect transistor for RF applications. This device structure can preserve the high mobility and the high carrier velocity of graphene, even when it is sandwiched ...

Taychatanapat, Thiti

424

Recent Progress of RF Cavity Study at Mucool Test Area  

DOE Green Energy (OSTI)

Summar of presentation is: (1) MTA is a multi task working space to investigate RF cavities for R&D of muon beam cooling channel - (a) Intense 400 MeV H{sup -} beam, (b) Handle hydrogen (flammable) gas, (c) 5 Tesla SC solenoid magnet, (d) He cryogenic/recycling system; (2) Pillbox cavity has been refurbished to search better RF material - Beryllium button test will be happened soon; (3) E x B effect has been tested in a box cavity - Under study (result seems not to be desirable); (4) 201 MHz RF cavity with SRF cavity treatment has been tested at low magnetic field - (a) Observed some B field effect on maximum field gradient and (b) Further study is needed (large bore SC magnet will be delivered end of 2011); and (5) HPRF cavity beam test has started - (a) No RF breakdown observed and (b) Design a new HPRF cavity to investigate more plasma loading effect.

Yonehara, Katsuya; /Fermilab

2011-12-02T23:59:59.000Z

425

Handbook for Gas Filled RF Cavity Aficionados'  

DOE Green Energy (OSTI)

The use of hydrogen gas filled RF cavities in muon cooling channels has been proposed by Rolland Johnson. Impressive results have been obtained toward attaining high voltage gradients and rapid training in preliminary tests done at the FNAL MTA facility. However, so far it has not been possible to test them under conditions where they were subject to the transversal of a high intensity particle beam. This note is an attempt to bring together a description of some of the pertinent physical processes that take place in the dilute plasma that is generated in the hydrogen gas by the beam. Two effects dominate. The first is that the free electrons generated can load down the cavity and transfer its energy to heating the gas. The second is a question of what happens to the plasma in the longer term. There is an enormous literature on the subject of the subject of dilute hydrogen plasmas and we can tap into this information in order to understand and predict the behavior of the cavity.

Tollestrup, A.V.; Chung, Moses; Yonehara, Katsuya; /Fermilab

2009-05-01T23:59:59.000Z

426

Low-power impulse UWB architectures and circuits  

E-Print Network (OSTI)

Ultra-wide-band (UWB) communication has a variety of applications ranging from wireless USB to radio frequency (RF) identification tags. For many of these applications, energy is critical due to the fact that the radios ...

Chandrakasan, Anantha P.

427

Micropower RF transponder with superregenerative receiver and RF receiver with sampling mixer  

DOE Patents (OSTI)

A micropower RF transponder employs a novel adaptation of the superregenerative receiver wherein the quench oscillator is external to the regenerative transistor. The quench oscillator applies an exponentially decaying waveform rather than the usual sinewave to achieve high sensitivity at microampere current levels. Further improvements include circuit simplifications for antenna coupling, extraction of the detected signal, and a low-voltage bias configuration that allows operation with less than a 1-volt rail voltage. The inventive transponder is expected to operate as long as the battery shelf life. 13 figs.

McEwan, T.E.

1997-05-13T23:59:59.000Z

428

Micropower RF transponder with superregenerative receiver and RF receiver with sampling mixer  

DOE Patents (OSTI)

A micropower RF transdponder employs a novel adaptation of the superregenerative receiver wherein the quench oscillator is external to the regenerative transistor. The quench oscillator applies an exponentially decaying waveform rather than the usual sinewave to achieve high sensitivity at microampere current levels. Further improvements include circuit simplifications for antenna coupling, extraction of the detected signal, and a low-voltage bias configuration that allows operation with less than a 1-volt rail voltage. The inventive transponder is expected to operate as long as the battery shelf life.

McEwan, Thomas E. (Livermore, CA)

1997-01-01T23:59:59.000Z

429

Rf power systems for the national synchrotron light source  

SciTech Connect

The booster synchrotron and the two storage rings at the NSLS are provided with rf power systems of 3 kW, 50 kW, and 500 kW nominal output power, all at 53 MHz. This power is supplied by grounded grid tetrode amplifiers designed for television broadcast service. These amplifiers and associated power supplies, control and interlock systems, rf controls, and computer interface are described.

Dickinson, T.; Rheaume, R.H.

1981-01-01T23:59:59.000Z

430

Radio channel modeling for mobile ad hoc wireless networks .  

E-Print Network (OSTI)

??The radio channel places fundamental limitations on the performance of mobile ad hoc wireless networks. In the mobile radio environment, fading due to multipath delay… (more)

Sng, Sin Hie

2004-01-01T23:59:59.000Z

431

Underground radio technology saves miners and emergency response...  

NLE Websites -- All DOE Office Websites (Extended Search)

Underground radio technology saves miners and emergency response personnel Underground radio technology saves miners and emergency response personnel Founded through LANL, Vital...

432

COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS  

Science Conference Proceedings (OSTI)

The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

2011-03-01T23:59:59.000Z

433

Synchronizing carrier frequencies of co-channel amplitude-modulated broadcast  

DOE Patents (OSTI)

Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

Smith, Stephen F. (London, TN); Moore, James A. (Powell, TN)

2007-05-15T23:59:59.000Z

434

Reinforcement learning based sensing policy optimization for energy efficient cognitive radio networks  

E-Print Network (OSTI)

This paper introduces a machine learning based collaborative multi band spectrum sensing policy for cognitive radios. The proposed sensing policy guides secondary users to focus the search of unused radio spectrum to those frequencies that persistently provide them high data rate. The proposed policy is based on machine learning, which makes it adaptive with the temporally and spatially varying radio spectrum. Furthermore, there is no need for dynamic modeling of the primary activity since it is implicitly learned over time. Energy efficiency is achieved by minimizing the number of assigned sensors per each subband under a constraint on miss detection probability. It is important to control the missed detections because they cause collisions with primary transmissions and lead to retransmissions at both the primary and secondary user. The minimization of the number of active sensors is formulated as a binary integer programming problem. Simulations show that the proposed machine learning based sensing policy ...

Oksanen, Jan; Koivunen, Visa

2011-01-01T23:59:59.000Z

435

Time and Frequency Portal  

Science Conference Proceedings (OSTI)

NIST Home > Time and Frequency Portal. Time and Frequency Portal. Programs and Projects. CODATA values of the fundamental constants ...

2013-06-27T23:59:59.000Z

436

DIFFUSIVE SHOCK ACCELERATION SIMULATIONS OF RADIO RELICS  

Science Conference Proceedings (OSTI)

Recent radio observations have identified a class of structures, so-called radio relics, in clusters of galaxies. The radio emission from these sources is interpreted as synchrotron radiation from GeV electrons gyrating in {mu}G-level magnetic fields. Radio relics, located mostly in the outskirts of clusters, seem to associate with shock waves, especially those developed during mergers. In fact, they seem to be good structures to identify and probe such shocks in intracluster media (ICMs), provided we understand the electron acceleration and re-acceleration at those shocks. In this paper, we describe time-dependent simulations for diffusive shock acceleration at weak shocks that are expected to be found in ICMs. Freshly injected as well as pre-existing populations of cosmic-ray (CR) electrons are considered, and energy losses via synchrotron and inverse Compton are included. We then compare the synchrotron flux and spectral distributions estimated from the simulations with those in two well-observed radio relics in CIZA J2242.8+5301 and ZwCl0008.8+5215. Considering that CR electron injection is expected to be rather inefficient at weak shocks with Mach number M {approx}< a few, the existence of radio relics could indicate the pre-existing population of low-energy CR electrons in ICMs. The implication of our results on the merger shock scenario of radio relics is discussed.

Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Ryu, Dongsu [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Jones, T. W., E-mail: kang@uju.es.pusan.ac.kr, E-mail: ryu@canopus.cnu.ac.kr, E-mail: twj@msi.umn.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2012-09-01T23:59:59.000Z

437

A self-calibration scheme for extended frequency-band-decomposition sigma-delta ADC  

Science Conference Proceedings (OSTI)

Frequency-band-decomposition (FBD) is a good candidate to be used to increase the bandwidths of ADC converters based on sigma-delta modulators for software and cognitive radio applications where we need to convert wide bandwidths. Each modulator processes ... Keywords: Analog-to-digital conversion, Bandpass, Filter bank, Frequency-band-decomposition, Self-calibration, Sigma-delta

Philippe Benabes; Ali Beydoun

2010-03-01T23:59:59.000Z

438

'Radio Wave Cooling' Offers New Twist on Laser Cooling  

Science Conference Proceedings (OSTI)

'Radio Wave Cooling' Offers New Twist on Laser Cooling. From NIST Tech Beat: September 13, 2007. ...

2013-07-08T23:59:59.000Z

439

LIMITS ON PROMPT, DISPERSED RADIO PULSES FROM GAMMA-RAY BURSTS  

Science Conference Proceedings (OSTI)

We have searched for prompt radio emission from nine gamma-ray bursts (GRBs) with a 12 m telescope at 1.4 GHz, with a time resolution of 64 {mu}s to 1 s. We detected single dispersed radio pulses with significances >6{sigma} in the few minutes following two GRBs. The dispersion measures of both pulses are well in excess of the expected Galactic values, and the implied rate is incompatible with known sources of single dispersed pulses. The arrival times of both pulses also coincide with breaks in the GRB X-ray light curves. A null trial and statistical arguments rule out random fluctuations as the origin of these pulses with >95% and {approx}97% confidence, respectively, although a simple population argument supports a GRB origin with confidence of only 2%. We caution that we cannot rule out radio frequency interference (RFI) as the origin of these pulses. If the single pulses are not related to the GRBs, we set an upper limit on the flux density of radio pulses emitted between 200 and 1800 s after a GRB of 1.27w {sup -1/2} Jy, where 6.4 Multiplication-Sign 10{sup -5} s 1 s) variations. These limits are some of the most constraining at high time resolution and GHz frequencies in the early stages of the GRB phenomenon.

Bannister, K. W.; Murphy, T.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics A29, University of Sydney, NSW 2006 (Australia); Reynolds, J. E., E-mail: keith.bannister@csiro.au [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

2012-09-20T23:59:59.000Z

440

High frequency inductive lamp and power oscillator  

DOE Patents (OSTI)

A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and I or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to adjust the driving frequency of the oscillator.

MacLennan, Donald A. (Gaithersburg, MD); Dymond, Jr., Lauren E. (North Potomac, MD); Gitsevich, Aleksandr (Montgomery Village, MD); Grimm, William G. (Silver Spring, MD); Kipling, Kent (Gaithersburg, MD); Kirkpatrick, Douglas A. (Great Falls, VA); Ola, Samuel A. (Silver Spring, MD); Simpson, James E. (Gaithersburg, MD); Trimble, William C. (Columbia, MD); Tsai, Peter (Olney, MD); Turner, Brian P. (Damascus, MD)

2001-01-01T23:59:59.000Z

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441

High frequency inductive lamp and power oscillator  

DOE Patents (OSTI)

A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to match the driving frequency of the oscillator to a plurality of tuning states of the lamp.

MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD); Dolan, James T. (Frederick, MD); Kirkpatrick, Douglas A. (Great Falls, VA); Leng, Yongzhang (Damascus, MD)

2000-01-01T23:59:59.000Z

442

RF Power Upgrade for CEBAF at Jefferson Laboratory  

Science Conference Proceedings (OSTI)

Jefferson Laboratory (JLab) is currently upgrading the 6GeV Continuous Electron Beam Accelerator Facility (CEBAF) to 12GeV. As part of the upgrade, RF systems will be added, bringing the total from 340 to 420. Existing RF systems can provide up to 6.5 kW of CW RF at 1497 MHZ. The 80 new systems will provide increased RF power of up to 13 kW CW each. Built around a newly designed and higher efficiency 13 kW klystron developed for JLab by L-3 Communications, each new RF chain is a completely revamped system using hardware different than our present installations. This paper will discuss the main components of the new systems including the 13 kW klystron, waveguide isolator, and HV power supply using switch-mode technology. Methodology for selection of the various components and results of initial testing will also be addressed. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

Andrew Kimber,Richard Nelson

2011-03-01T23:59:59.000Z

443

rf improvements for Spallation Neutron Source H ion source  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering 38 mA H beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride AlN plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier. 2010 American Institute of Physics.

Kang, Yoon W [ORNL; Fuja, Raymond E [ORNL; Goulding, Richard Howell [ORNL; Hardek, Thomas W [ORNL; Lee, Sung-Woo [ORNL; McCarthy, Mike [ORNL; Piller, Chip [ORNL; Shin, Ki [ORNL; Stockli, Martin P [ORNL; Welton, Robert F [ORNL

2010-01-01T23:59:59.000Z

444

GNSS radio occultation constellation observing system experiments  

Science Conference Proceedings (OSTI)

Observing system experiments within the operational ECMWF data assimilation framework have been performed for summer 2008 when the largest recorded number of GNSS radio occultation observations from both operational and experimental satellites ...

Peter Bauer; Gábor Radnóti; Sean Healy; Carla Cardinali

445

Errors in Radio Acoustic Sounding of Temperature  

Science Conference Proceedings (OSTI)

With the use of simultaneous correction for radial wind, the accuracy of radio acoustic sounding systems for the measurement of temperature has been substantially improved. The temperature accuracy can now be affected by a number of factors that ...

Wayne M. Angevine; W. L. Ecklund

1994-06-01T23:59:59.000Z

446

Electromagnetic Compatibility from a Time-Frequency Perspective  

E-Print Network (OSTI)

Abstract — In wireless communication, interference between two radio systems may occur when they operate at close frequency bands, sharing the same environment at the same time. Such systems coexist if both of them perform correctly in the presence of the other. To ensure their coexistence, Electromagnetic Compatibility (EMC) is used to specify rules within standardization bodies. According to current EMC standards, the radio spectrum has been divided into non-overlapping bands often with exclusive access. However, nowadays there is a proliferation of new digital systems sharing common frequency bands because the spectrum is a limited resource. Many of them are operating in unlicensed bands regulated by The International Telecommunications Union (ITU), for example the 2.45 GHz Industrial, Scientific and Medical (ISM) band. The frequency allocation is also changing with the emergence of digital systems and this is the case for white spaces in the broadcast television (TV) spectrum. To avoid high interference levels, it is necessary to consider some parameters related to signal variations, representing more accurately the environment. Some techniques have been proposed in the literature to reduce interference levels but they are applied to specific sharing studies. Hence, we evaluate in this paper the impact of time-frequency considerations for radio coexistence. We show that EMC studies are more precise and more representative of the reality when additional parameters relevant to the time domain are taken into account in the analysis framework. We illustrate these concepts through a specific study case. We evaluate the results for different system parameters, first considering that both of them occupy the same band and then assuming that they use overlapping but non-equal frequency bands. Index Terms — Radio coexistence, electromagnetic compatibility, frequency-domain analysis, time-domain analysis.

Najett Neji; Raul De Lacerda; Alain Azoulay; Thierry Letertre

2013-01-01T23:59:59.000Z

447

Mechanical and thermal analysis of beryllium windows for RF cavities in a muon cooling channel  

SciTech Connect

Thin beryllium windows (foils) may be utilized to increase shunt impedance of closed-cell RF cavities. These windows are subject to ohmic heating from RF currents. The resulting temperature gradients in the windows can produce out of plane displacements that detune the cavity frequency. The window displacement can be reduced or eliminated by pre-stressing the foils in tension. Because of possible variations during manufacture, it is important to quantify the actual prestress of a Be window before it is put into service. We present the thermal and mechanical analyses of such windows under typical operating conditions and describe a simple non-destructive means to quantify the pre-stress using the acoustic signature of a window. Using finite element analysis, thin plate theory and physical measurements of the vibration modes of a window we attempted to characterize the actual Be window pre-stress in a small number of commercially sourced windows (30% of yield strength is typical). This method can be used for any window material and size, but this study focused on 16 cm diameter Be Windows ranging in thickness from 125 microns to 508 microns and with varying pre-stresses. The method can be used to nondestructively test future Be windows for the desired prestress.

Li, Derun; Ladran, A.; Lozano, D.; Rimmer, R.

2002-05-30T23:59:59.000Z

448

Kinetically Dominated FRII Radio Sources  

E-Print Network (OSTI)

The existence of FR II objects that are kinetically dominated, the jet kinetic luminosity, $Q$, is larger than the total ther