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Development of a Quantum-Limited Microwave Amplifier using a dc Superconducting Quantum Interference Device (dc-SQUID)

Description: This report summarizes the research performed on the LDRD project 02-ERD-071 to develop a quantum-limited microwave amplifier based on a dc Superconducting Quantum Interference Device (dc-SQUID). This project began in June 2002 and concluded in May 2005. This project produced the lowest noise temperature amplifiers ever produced, both in absolute terms and in relation to the Standard Quantum Limit. Being an order of magnitude lower in noise than the best HFET devices available, they are of great interest to a number of groups. Potential applications are numerous, from dark-matter searches to national security applications in Quantum Information Processing. Collaborations started during this project are continuing with the goal of single-spin detection using the rf-SET. Publications are forthcoming covering both the experimental results and the theoretical modeling. The most important publication with the noise temperature results will appear after the low frequency follow-up experiment. The other publications in production cover the input impedance measurements and the resulting transmission line models.
Date: December 11, 2006
Creator: Kinion, D
Partner: UNT Libraries Government Documents Department

Development of a thermionic magnicon amplifier at 11.4 GHz. Technical progress report, 16 May 1994--31 December 1995

Description: This is a progress report on a four-year research program entitled `Development of a Thermionic Magnicon Amplifier at 11.4 GHz`, which is under way in the Plasma Physics Division of the Naval Research Laboratory (NRL) under Interagency Agreement DE-AI02-94ER40681. This report covers the period 16 May 1994 through 31 December 1995. The magnicon is an advanced microwave tube with potential application to future high gradient linear accelerators such as TeV colliders. Under this program, NRL plans to build and test a thermionic magnicon amplifier tube powered by a 500 kV, 200 A, 10 Hz modulator with a 1 {mu}sec pulse. However, the experiments that were carried out during the period covered by this report were driven by a single-shot Marx generator, and the electron beam was produced from a graphite plasma cathode.
Date: December 31, 1995
Creator: Gold, S.H.; Fliflet, A.W. & Manheimer, W.M.
Partner: UNT Libraries Government Documents Department

Intense high-frequency gyrotron-based microwave beams for material processing

Description: Microwave processing of materials has traditionally utilized frequencies in the 0.915 and 2.45 GHz regions. Microwave power sources are readily available at these frequencies but the relatively long wavelengths can present challenges in uniformly heating materials. An additional difficulty is the poor coupling of ceramic based materials to the microwave energy. Los Alamos National Laboratory scientists, working in conjunction with the National Center for Manufacturing Sciences (NCMS), have assembled a high-frequency demonstration processing facility utilizing gyrotron based RF sources. The facility is primarily intended to demonstrate the unique features available at frequencies as high as 84 GHz. The authors can readily provide quasi-optical, 37 GHz beams at continuous wave (CW) power levels in the 10 kW range. They have also provided beams at 84 GHz at 10 kW CW power levels. They are presently preparing a facility to demonstrate the sintering of ceramics at 30 GHz. This paper presents an overview of the present demonstration processing facility and describes some of the features they have available now and will have available in the near future.
Date: March 1, 1997
Creator: Hardek, T.W.; Cooke, W.D.; Katz, J.D.; Perry, W.L. & Rees, D.E.
Partner: UNT Libraries Government Documents Department

ECH mirror interface tank for 110 GHz, 1 MW gyrotron

Description: A 1 MW, 110 GHz gyrotron is to be installed at General Optical Atomics in 1995. A Mirror Optics Unit (MOU) has been Unit designed and built to connect to the existing 110 GHz transmission line system. The unit reduces and directs a 145 mm diameter beam from the gyrotron to a 19 mm diameter beam which is then injected into a 31.8 mm diameter corrugated waveguide of the transmission line system. The unit operates under vacuum and is able to absorb beam spray from the gyrotron. The tank also contains various diagnostics equipment to protect the gyrotron and to determine the amount of energy loss in the tank, and at the window of the gyrotron output. This paper discusses further the design parameters, assembly and installation of the unit in the transmission line system.
Date: October 1, 1995
Creator: O`Neil, R.C.; Callis, R.W.; Cary, W.P.; Doane, J.L.; Gallix, R.; Hodapp, T.R. et al.
Partner: UNT Libraries Government Documents Department

Magnicon development to power TeV colliders. Final report, 16 May 1991--14 May 1994

Description: The goal of this program was the development of a high power frequency-doubling magnicon amplifier at 11.4 GHz. The magnicon is an advanced {open_quotes}scanning-beam{close_quotes} microwave amplifier tube for use in powering future high gradient linear accelerators, such as the proposed TeV linear collider known as the Next Linear Collider (NLC). The rf source for the NLC must provide a power of 500 MW to 1 GW per tube in a 200 nsec pulse at a frequency in the range of 10-20 GHz. The required power can either be generated directly in 200 nsec pulses, or generated at longer pulse lengths (e.g., 1-2 {mu}sec) and then pulse-compressed. Because the average power required by the NLC is so large, source efficiency is a crucial consideration.
Date: April 1, 1997
Creator: Gold, S.H.; Manheimer, W.M. & Fliflet, A.
Partner: UNT Libraries Government Documents Department

The 110 GHz ECH installation on DII-D: Status and initial experimental results

Description: Two 110 GHz gyrotrons with nominal output power of 1 MW each have been installed on the DIII-D tokamak. The gyrotrons, produced by Gycom and Communications and Power Industries, are connected to the tokamak by windowless evacuated transmission lines using circular corrugated waveguide carrying the HE{sub 11} mode. Initial experiments with the Gycom gyrotron showed good central heating efficiency at the second harmonic resonance with record central electron temperatures for DIII-D in excess of 10 keV achieved. The beam spot in the DIII-D vacuum vessel was well focused, with a diameter of approximately 8 cm, and it could be steered poloidally by a remotely adjustable mirror. The injection was at 19 deg off-perpendicular for current drive and the beams could be modulated for studies of energy transport and power deposition. The system will be described and the initial physics results will be presented. A third gyrotron, also at 110 GHz, will be installed later this year. Progress with this CPI tube will be discussed and future plans for the ECH installation and physics experiments using it will be presented.
Date: May 1997
Creator: Lohr, J.; Callis, R.W. & O`Neill, R.C.
Partner: UNT Libraries Government Documents Department

TFTR 60 GHz alpha particle collective Thomson Scattering diagnostic

Description: A 60 GHz gyrotron collective Thomson Scattering alpha particle diagnostic has been implemented for the D-T period on TFM. Gyrotron power of 0.1-1 kW in pulses of up to 1 second can be launched in X-mode. Efficient corrugated waveguides are used with antennaes and vacuum windows of the TFTR Microwave Scattering system. A multichannel synchronous detector receiver system and spectrum analyzer acquire the scattered signals. A 200 Megasample/sec digitizer is used to resolve fine structure in the frequency spectrum. By scattering nearly perpendicular to the magnetic field, this experiment will take advantage of an enhancement of the scattered signal which results from the interaction of the alpha particles with plasma resonances in the lower hybrid frequency range. Significant enhancements are expected, which will make these measurements possible with gyrotron power less than 1 kW, while maintaining an acceptable signal to noise ratio. We hope to extract alpha particle density and velocity distribution functions from the data. The D and T fuel densities and temperatures may also be obtainable by measurement of the respective ion cyclotron harmonic frequencies.
Date: March 1995
Creator: Machuzak, J. S.; Woskov, P. P.; Gilmore, J.; Bretz, N. L.; Park, H. K.; Aamodt, R. E. et al.
Partner: UNT Libraries Government Documents Department

Initial results from the multi-megawatt 110 GHz ECH system for the DIII-D tokamak

Description: The first of three MW-level 110 GHz gyrotrons was operated into the DIII-D tokamak in late 1996. Two additional units will be commissioned during 1997. Each gyrotron is connected to the tokamak by a low loss, windowless, evacuated transmission line using circular corrugated waveguide carrying the HE{sub 11} mode. The microwave beam spot is well focused with a spot size of approximately 6 cm and can be steered poloidally from the center to the outer edge of the plasma. The initial operation with about 0.5 MW delivered to a low density plasma for 0.5 s showed good central electron heating, with peak temperature in excess of 10 keV. The injection was 19{degree} off perpendicular for current drive.
Date: April 1, 1997
Creator: Callis, R.W.; Lohr, J.; O`Neill, R.C.; Ponce, D.; Luce, T.C.; Prater, R. et al.
Partner: UNT Libraries Government Documents Department

Complementary HFET technology for wireless digital and microwave applications

Description: Development of a complementary heterostructure field effect transistor (CHFET) technology for low-power, mixed-mode digital-microwave applications is presented. Digital CHFET technology with independently optimizable transistors has been shown to operate with 319 ps loaded gate delays at 8.9 fJ. Power consumption is dominated by leakage currents of the p-channel FET, while performance is determined by the characteristics of 0.7 {mu}m gate length devices. As a microwave technology, the nJFET forms the basis of low-power cirucitry without any modification to the digital process. Narrow band amplification with a 0.7x100 {mu}m nJFET has been demonstrated at 2.1-2.4 GHz with gains of 8-10 dB at 1 mW power. These amplifiers showed a minimum noise figure of 2.5 dB. Next generation CHFET transistors with sub 0.5 {mu}m gate lengths have also been developed. Cutoff frequencies of 49 and 11.5 GHz were achieved for n- and p-channel FETs with 0.3 and 0.4 {mu}m gates, respectively. These FETs will enable enhancements in both digital and microwave circuits.
Date: September 1, 1996
Creator: Baca, A.G.; Zolper, J.C. & Dubbert, D.F.
Partner: UNT Libraries Government Documents Department

Precision characterization of gyrotron window materials. Final report, September 1, 1995--April 30, 1997

Description: An optical resonator has been constructed to measure dielectric properties of materials at millimeter wavelengths. The objectives are the identification and loss measurements of window materials for high power gyrotrons. The source of radiation is from a backward wave oscillator (BWO) with enhanced power, good stability, and spectral purity. The measurement technique is based on the application of a high Q Fabry-Perot resonator which provides a means of determining the difference in the reciprocal Q-factors with high accuracy. Initial loss measurements at 150 GHz at room temperature are performed on sapphire. Preliminary loss tangent results on sapphire is found to be around 10{sup {minus}4} and are reported here. Work is in progress to develop a system which will scan the resonance rapidly to produce a measurement in less than a minute and to measure the loss as a function of temperature.
Date: March 3, 1998
Creator: Dutta, J.M. & Jones, C.R.
Partner: UNT Libraries Government Documents Department

Gyrotron-based millimeter-wave beams for material processing

Description: Los Alamos scientists, working with the National Center for Manufacturing Sciences have assembled a materials processing facility utilizing gyrotron based RF sources. The facility is intended to demonstrate unique features available at 30 to 84 GHz. This paper presents an overview of their quasi-optical facility and describes the microwave hardware.
Date: October 1, 1997
Creator: Hardek, T.W.; Cooke, W.D.; Perry, W.L. & Rees, D.E.
Partner: UNT Libraries Government Documents Department

GaAs-based JFET and PHEMT technologies for ultra-low-power microwave circuits operating at frequencies up to 2.4 GHz

Description: In this work the authors report results of narrowband amplifiers designed for milliwatt and submilliwatt power consumption using JFET and pseudomorphic high electron mobility transistors (PHEMT) GaAs-based technologies. Enhancement-mode JFETs were used to design both a hybrid amplifier with off-chip matching as well as a monolithic microwave integrated circuit (MMIC) with on-chip matching. The hybrid amplifier achieved 8--10 dB of gain at 2.4 GHz and 1 mW. The MMIC achieved 10 dB of gain at 2.4 GHz and 2 mW. Submilliwatt circuits were also explored by using 0.25 {micro}m PHEMTs. 25 {micro}W power levels were achieved with 5 dB of gain for a 215 MHz hybrid amplifier. These results significantly reduce power consumption levels achievable with the JFETs or prior MESFET, heterostructure field effect transistor (HFET), or Si bipolar results from other laboratories.
Date: May 1, 1998
Creator: Baca, A.G.; Hietala, V.M.; Greenway, D.; Shul, R.J.; Hafich, M.J.; Zolper, J.C. et al.
Partner: UNT Libraries Government Documents Department

The DIII-D ECH multiple gyrotron control system

Description: DIII-D`s ECH upgrade with 1 MW, 110 GHz gyrotrons is ongoing, and with it, an upgrade of the control system. The ECH Multiple Gyrotron Control System uses software distributed among networked computers, interfaced to a programmable logic controller (PLC), the timing and pulse system, power supplies, vacuum and wave guide controls, and instrumentation. During DIII-D operations, the system will allow a chief and a co-operator to control and monitor a number of gyrotrons from different manufacturers. The software, written using LabVIEW, allows for remote and multiple operator control. Thus any supported computer can become a control station and multiple projects can be simultaneously accommodated. Each operator can be given access to the controls of all gyrotrons or to a subset of controls. Status information is also remotely available. The use of a PLC simplifies the hardware and software design. It reduces interlock and control circuitry, includes monitoring for slow analog signals, and allows one software driver to efficiently interface to a number of systems. In addition, the interlock logic can be easily changed and control points can be forced as needed. The pulse system is designed around arbitrary function generators. Various modulation schemes can be accommodated, including real-time control of the modulation. This discussion will include the hardware and software design of the control system and its current implementation.
Date: November 1, 1997
Creator: Ponce, D.; Lohr, J.; Tooker, J.F.; Cary, W.P. & Harris, T.E.
Partner: UNT Libraries Government Documents Department

The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

Description: Over the next three years the DIII-D National Fusion Facility at General Atomics will upgrade its electron cyclotron heating (ECH) capability from the present 3 MW at 110 GHz to 10 MW of injected microwave power. There will be ten gyrotron tubes supplied by five 8.4 MW modulator/regulator (M/R) power systems. The project has gained considerable leverage from the acquisition of surplus hardware from the MFTF program that was conducted at LLNL in the early 1980s. One of these systems had been refurbished and converted for use as an ECH power supply earlier. The experience gained and the lessons learned from operating that system have proved valuable in guiding the engineering of the new systems. This paper provides an overview of the power system design and a report on the present status of the project.
Date: December 1999
Creator: Pronko, S. G. E. & Baggest, D. S.
Partner: UNT Libraries Government Documents Department

[Advanced accelerator R and D program]. Final report

Description: This proposal requests funding for a 3-year renewal of the DOE advanced accelerator R and D (AARD) program at Texas A and M University. The program to date has focused on the development of the gigatron, a compact high-efficiency microwave driver for future linear colliders. The author reports results and progress in that project, and plans to bring it to a milestone and conclusion by mid-1995. He proposes to initiate a second project, the development of a new technology for ultra-high field superconducting magnets for future hadron colliders. This project builds upon two magnet designs which he has introduced during the past year, which have the potential for a dramatic extension of the achievable field strength for both dipoles and quadrupoles.
Date: December 31, 1997
Partner: UNT Libraries Government Documents Department

Characterization of a klystrode as a RF source for high-average-power accelerators

Description: The klystrode is a relatively new type of RF source that has demonstrated dc-to-RF conversion efficiencies in excess of 70% and a control characteristic uniquely different from those for klystron amplifiers. The different control characteristic allows the klystrode to achieve this high conversion efficiency while still providing a control margin for regulation of the accelerator cavity fields. The authors present test data from a 267-MHz, 250-kW, continuous-wave (CW) klystrode amplifier and contrast this data with conventional klystron performance, emphasizing the strengths and weaknesses of the klystrode technology for accelerator applications. They present test results describing that limitation for the 250-kW, CW klystrode and extrapolate the data to other frequencies. A summary of the operating regime explains the clear advantages of the klystrode technology over the klystron technology.
Date: May 1, 1995
Creator: Rees, D.; Keffeler, D.; Roybal, W. & Tallerico, P.J.
Partner: UNT Libraries Government Documents Department

T25 ITER ECH window development 110 GHz ECH distributed window development. Final report, May 1, 1994--December 31, 1995

Description: Electron Cyclotron Heating (ECH) is one of the major candidates for Heating and Current Drive on ITER. ECH is extremely attractive from a reactor engineering point of view, offering compact launch structures, high injected power density, and a simple interface with the shield/blanket. Economic deployment of ECH for ITER requires MW unit microwave sources (gyrotrons). The present technology limitation is the availability of suitable low loss output windows. These are needed for the torus as well as the tube. The torus window, in particular, is a demanding application as it also serves as a tritium barrier. Several distinct window concepts are under development by the various Parties. This report summarizes the efforts to make and test a {open_quotes}distributed{close_quotes} window suitable for 1 MW cw operation at 110 GHz. A companion report (Final Report on Task 245+) describes the efforts to make a distributed window suitable for 1 MW cw operation at 170 GHz, the main frequency of interest to ITER. General Atomics (GA) fabricated a 4 in. x 4 in. 110 GHz distributed window which was delivered in September 1995 to Communications and Power Industries (CPI). Hot tests at CPI confirmed the power handling capability of the window. Tests were conducted with a reduced beam size at 200 kW with 0.7 s pulses without any arcing or excessive window temperatures. The power density and pulse length were equivalent to that in a full size 1.2 MW CW beam with a peak-to-average power ratio of 2.7. This window was assembled using a gold braze material to bond the sapphire strips to the niobium frame. The braze was successful except for small leaks at two locations, and re-braze efforts were unsuccessful.
Date: January 1, 1998
Creator: Olstad, R.A.; Moeller, C.P. & Grunloh, H.J.
Partner: UNT Libraries Government Documents Department

The amplitude and phase control of the ALS Storage Ring RF System

Description: A 500MHz, 300KW Klystron power amplifier provides RF power to the ALS Storage Ring. In order to accommodate the amplitude and phase changes during beam stacking and decay, which demand continuously varying power levels from the Klystron, four loops are used to keep the system operating properly, with two of those loops dedicated to keeping the two cavity tuners on tune. Description of the control loops and their performance data will be given. Using the modulation anode of the Klystron in the amplitude loop will be discussed.
Date: March 1, 1995
Creator: Lo, C.C.; Taylor, B. & Baptiste, K.
Partner: UNT Libraries Government Documents Department

Quasi-optical gyrotron materials processing at Los Alamos

Description: Los Alamos has recently obtained and installed quasi-optical gyrotrons of 37 and 84 GHz with power outputs up to 35 kW. A quasi-optical gyrotron is unique in that the output is a Gaussian beam which can be focused and manipulated using mirrors. The Gaussian beam output is ideally suited for one and two dimensional materials processing applications such as joining and surface treatment. Working with the National Center for Manufacturing Sciences (NCMS) we have formed a consortium of companies to investigate several materials processing applications.
Date: May 1, 1995
Creator: Katz, J.D. & Rees, D.E.
Partner: UNT Libraries Government Documents Department

Collective acceleration of electrons and ions in a high current relativistic electron beam. Final report

Description: This report describes work carried out on DOE contract number DE-AC02-80ER10569 during the period December 15, 1979 to May 31, 1992. The original purpose of this research was to investigate the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three major objectives: development of a suitable ion injector, growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components into a suitable proof-of-principle demonstration of the wave accelerator. Work focused on the first two of these objectives. Control of the space charge waves` phase velocity was not obtained to the degree required for a working accelerator, so the project was duly terminated in favor of a program which focused on generating ultra high power microwave signals suitable for use in the next linear collider. Work done to develop suitable efficient, inexpensive, phase-stable microwave sources, with peak powers of up to 1 GW in the X band in pulses shorter than 1 ns, is described. Included are lists of the journal and conference papers resulting from this work, as well as a list of graduate students who completed their Ph.D. studies on the projects described in this report.
Date: December 31, 1992
Creator: Nation, J.A.
Partner: UNT Libraries Government Documents Department

Complementary HFET technology for low-power mixed-mode applications

Description: Development of a complementary heterostructure field effect transistor (CHFET) technology for low-power, mixed-mode digital-microwave applications is presented. An earlier digital CHFET technology with independently optimizable transistors which operated with 319 ps loaded gate delays at 8.9 fJ is reviewed. Then work demonstrating the applicability of the digital nJFET device as a low-power microwave transistor in a hybrid microwave amplifier without any modification to the digital process is presented. A narrow band amplifier with a 0.7 {times} 100 {micro}m nJFET as the active element was designed, constructed, and tested. At 1 mW operating power, the amplifier showed 9.7 dB of gain at 2.15 GHz and a minimum noise figure of 2.5 dB. In addition, next generation CHFET transistors with sub 0.5 {micro}m gate lengths were developed. Cutoff frequencies, f{sub t} of 49 GHz and 11.5 GHz were achieved for n- and p-channel FETs with 0.3 and 0.4 {micro}m gates, respectively. These FETs will enable both digital and microwave circuits with enhanced performance.
Date: June 1, 1996
Creator: Baca, A.G.; Sherwin, M.E.; Zolper, J.C.; Dubbert, D.F.; Hietala, V.M.; Shul, R.J. et al.
Partner: UNT Libraries Government Documents Department

Self-Aligned GaAs JFETs for Low-Power Microwave Amplifiers and RFICs at 2.4 GHz

Description: Self-aligned GaAs JFET narrowband amplifiers operating at 2.4 GHz were designed and fabricated with both discrete WETS as a hybrid amplifier and as RFICS. Enhancement-mode JFETs were used in order to be compatible with complementary digital logic. Hybrid amplifiers achieved 8-10 dB of gain at 2.4 GHz and 1 mW DC bias level. The RFIC achieved 10 dB of gain at 24 GHz and 2 mW DC bias level.
Date: November 2, 1998
Creator: Baca, A.G.; Dubbert, D.F.; Greenway, D.; Hietala, V.M.; Shul, R.J.; Sloan, L.R. et al.
Partner: UNT Libraries Government Documents Department