摘要:

The High Power Radio Frequency (HPRF) Faraday Partnership is a UK technology forum for all users, designers, developers and researchers of RF and microwave devices and systems. High power RF and microwave engineering are key enabling technologies in a wide range of industrial sectors. Formed in October 2001 and funded initially by the UK Department of Trade and Industry and the UK Particle Physics and Astronomy Research Council, the purpose of the HPRF Faraday Partnership is the development of a vibrant research, development and manufacturing base capable of exploiting opportunities in high power radio‐frequency engineering. The partnership includes the key UK industrial companies, research laboratories and university research groups. The number of partners is constantly growing and already numbers over thirty. The partnership provides the enabling technology for future high power RF systems and their power supplies through its research programme. It is training people for the sector through PhD studentships and employment as Research Associates. It is planned to develop a Masters Training program. Support and involvement in research for companies in the supply chain is provided through a Partnership Office, a web site and through a range of government funded research schemes. The HPRF Faraday Partnership is seeking to establish more long term international research and development collaborations. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635136

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A high‐power, coherent, W‐band (94 GHz) millimeter‐wave radar has been developed at the Naval Research Laboratory. This radar, named WARLOC, employs a 100 kW peak power, 10 kW average power gyro‐klystron as the final power amplifier, an overmoded transmission line system, and a quasi‐optical duplexer, together with a high gain antenna, four‐channel receiver, and state‐of‐the‐art signal processing. The gyro‐amplifiers and the implementation in the WARLOC radar will be described. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635137

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The Naval Research Laboratory has recently developed a 3–10 kW average, 80 kW peak power 94 GHz radar with scanning capability, WARLOC. This radar is powered by a gyroklystron developed by a team led by NRL. One application has been to image clouds. New capabilities of WARLOC include imaging with greatly improved sensitivity and detail as well as the ability to detect much lower strength cloud returns. Here we show how pulse averaging enhances the sensitivity of WARLOC. Since the available power is so high, it can be used in moderate rain to both measure the rainfall rate and to image the cloud above the rain. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635138

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A number of promising new ideas, proposed and experimentally realized recently in the old field of gyrodevices, are reviewed. These results open possibilities for creation of effective frequency‐broad‐band devices and for advancement into submillimeter‐wavelength band at high level of RF power. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635139

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

This paper reports on progress on a high‐power mm‐wave source concept being pursued at Los Alamos. The concept is based on passing a high‐brightness, sheet electron beam through a slow‐wave structure created from a vane‐loaded waveguide. Component development was conducted with at 10‐kV experiment, and design work and fabrication work has been conducted for a demonstration experiment with a 120‐kV, 20‐A sheet electron beam operating at 95 GHz. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635140

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A compact source of monoenergetic X‐rays generated via Compton backscattering is under development at SLAC. It consists of a Photoinjector operating at 11.424 GHz, a stage of post acceleration using a 1.05 m long high gradient accelerator structure and an interaction chamber where a high power (TW), short pulse (sub‐ps) infrared laser beam with a high quality focused electron beam are brought into collision. Successful completion of this project will result in the capability of generating a monoenergetic X‐ray beam, continuously tunable from 20 – 85 keV. All components have been installed and initial testing has commenced. We are currently generating and accelerating an electron beam up to the accelerator and measuring the essential beam parameters, i.e., quantum efficiency, emittance, energy and stability. The latest test results will be presented together with a description of the beamline components and laser system. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635141

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The plasma‐assisted slow wave oscillator (Pasotron) employs a plasma lens for initial focusing of the driving electron beam, enabling operation without a magnetic field. In this study, the XOOPIC particle‐in‐cell code is used to model the beam interaction with an expanding background neutral gas. The 40 kV beam electrons impact‐ionize the background gas, displacing the less energetic plasma electrons, and focusing the nominally 50 A beam in the neutralizing space charge of the remaining plasma ions. A particle‐in‐cell (PIC) Monte Carlo collision (MCC) model is described. The model treats charged particles (beam electrons, plasma electrons and ions) as particles. Collisions between charged particles (electrons and ions) and neutrals are included using a Monte Carlo collision model with a spatially‐dependent helium gas background. Time‐dependent space charge and self‐magnetic forces are included. The model is used to study beam focusing, as well as oscillations and instabilities at higher currents. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635142

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Electron beams propagating in the ion focused regime (Bennett pinch) are of interest for various sources of coherent electromagnetic radiation (pasotrons, ion‐channel lasers, ion‐channel guided free‐electron lasers). The transition of a beam from a quasi‐laminar state near the gun to a phase‐mixed equilibrium state is accompanied with appearance of betatron oscillations. In pasotrons these oscillations play a negative role because they often result in certain beam losses due to the interception of beam electrons oscillating with large amplitudes by the chamber walls. The betatron oscillations and the beam losses can be monitored by using a weak local external magnetic field (magnetic lens) in the transition region. The results obtained show that, by using a properly designed and positioned magnetic lens, a halo in the phase‐mixed beam can be greatly reduced and the beam losses can be practically eliminated. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635143

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A comparative analysis between conventional four‐cavity and three‐stage clustered‐cavity gyroklystrons is performed. The efficiency, gain and bandwidth of each scheme are analyzed. The results show that the conventional tube has a slightly higher efficiency, however the clustered‐cavity scheme has an advantage in its bandwidth properties, gain and the gain‐bandwidth product. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635144

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

This paper presents a new, “magnetic‐ring”, slow‐wave structure (SWS), which provides an excellent interaction with a cylindrical electron beam. Formed by a periodic row of rings made from material with a relatively high permeability, such a SWS produces aquasi‐E01wave, similar to that in the iris‐loaded waveguide. The deceleration is due to the rings’ permeability. The electric field is purely inductive, forming longitudinally oriented ellipses around the magnetic rings. The absence of an azimuthal component of electric field in the slow wave makes it possible to manufacture magnetic rings from non‐conducting materials, as well as from thin conducting layers, e.g. tape rings made from amorphous iron. A pipe, made from a non‐conductive material with finite permeability, also can replace a periodic row of magnetic rings. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1635145

出版商:AIP    

年代:1903

数据来源: AIP