WorldWideScience

Sample records for 14-w 140-ghz gyrotron

  1. Operational Characteristics of a 14-W 140-GHz Gyrotron for Dynamic Nuclear Polarization

    OpenAIRE

    Joye, Colin D.; Griffin, Robert G.; Hornstein, Melissa K.; Hu, Kan-Nian; Kreischer, Kenneth E.; Rosay, Melanie; Shapiro, Michael A; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Woskov, Paul P.

    2006-01-01

    The operating characteristics of a 140-GHz 14-W long pulse gyrotron are presented. The device is being used in dynamic nuclear polarization enhanced nuclear magnetic resonance (DNP/NMR) spectroscopy experiments. The gyrotron yields 14 W peak power at 139.65 GHz from the TE(0,3) operating mode using a 12.3-kV 25-mA electron beam. Additionally, up to 12 W peak has been observed in the TE(2,3) mode at 136.90 GHz. A series of mode converters transform the TE(0,3) operating mode to the TE(1,1) mod...

  2. Velocity diagnostics of electron beams within a 140 GHz gyrotron

    International Nuclear Information System (INIS)

    Experimental measurements of the average axial velocity vparallel of the electron beam within the M.I.T. 140 GHz MW gyrotron have been performed. The method involves the simultaneous measurement of the radial electrostatic potential of the electron beam Vp and the beam current Ib. Vp is measured through the use of a capacitive probe installed near or within the gyrotron cavity, while Ib is measured with a previously installed Rogowski coil. Three capacitive probes have been designed and built, and two have operated within the gyrotron. The probe results are repeatable and consistent with theory. The measurements of vparallel and calculations of the corresponding transverse to longitudinal beam velocity ratio α = vperpendicular/vparallel at the cavity have been made at various gyrotron operation parameters. These measurements will provide insight into the causes of discrepancies between theoretical rf interaction efficiencies and experimental efficiencies obtained in experiments with the M.I.T. 140 GHz MW gyrotron. The expected values of vparallel and α are determined through the use of a computer code entitled EGUN. EGUN is used to model the cathode and anode regions of the gyrotron and it computes the trajectories and velocities of the electrons within the gyrotron. There is good correlation between the expected and measured values of α at low α, with the expected values from EGUN often falling within the standard errors of the measured values. 10 refs., 29 figs., 2 tabs

  3. Start current analysis of a 140 GHz CPI gyrotron

    Science.gov (United States)

    Yeddulla, M.; Nusinovich, G. S.; Antonsen, T. M.

    2003-12-01

    In a gyrotron, it is difficult to accurately predict in advance where the resonant interaction between the electrons and outgoing radiation stops. For accurately calculating the start currents for the interacting modes, the exit coordinate has to be fixed where the resonant interaction stops. This paper discusses the difficulty in fixing the exit coordinates for studying start currents in an overmoded gyrotron. Start currents are studied for the operating and the most dangerous parasitic mode of a 140 GHz gyrotron being developed by Communication and Power Industries (CPI). Calculations show that the start currents vary over considerably large values with varying exit coordinates that can cause difficulties in predicting which mode dominates the mode competition.

  4. 140 GHz gyrotron development program. Quarterly report No. 4, January-March 1985

    International Nuclear Information System (INIS)

    The objective of this program is to develop a gyrotron oscillator capable of producing 100 kW CW at 140 GHz. Further analysis of the electron guns, interaction cavity, and beam tunnel designs for the first two experimental tubes, Experimental Tube 1 and preprototype Tube 1, is presented. A window deflection tester has been built and initial deflection test results are given. The first 140 GHz gyrotron magnet has successfully passed the major points in the acceptance test. The detailed results of the magnet acceptance test are discussed. Progress concerning the fabrication of 149 GHz gyrotron components, diagnostics, and protective devices, as well as the status of Experimental Tube 1, are summarized

  5. Design and operation of 140 GHz gyrotron oscillators for power levels up to 1 MW CW

    Energy Technology Data Exchange (ETDEWEB)

    Jory, H.; Bier, R.; Craig, L.J.; Felch, K.; Ives, L.; Lopez, N.; Spang, S.

    1986-12-01

    Varian has designed and tested 140 GHz gyrotron oscillators that have generated output powers of 100 kW CW and 200 kW for 1 ms pulses. Upcoming tubes will be designed to operate at power levels of 200 kW CW and ultimately up to 1 MW CW. The important design considerations which are addressed in the higher power tubes include the design of the electron gun, interaction circuit, and output window. These issues will be discussed and the results of the earlier 140 GHz gyrotron work at Varian will be summarized.

  6. Recent operating experience with Varian 70 GHz and 140 GHz gyrotrons

    International Nuclear Information System (INIS)

    The design features and initial test results of Varian 70 GHz and 140 GHz CW gyrotrons are presented. The first experimental 140 GHz tube has achieved an output power of 102 kW at 24% efficiency under pulsed conditions in the desired TE0310 cavity mode. Further tests aimed at achieving the design goal of 100 kW CW are currently underway. The 70 GHz tube has achieved an output power of 200 kW under pulsed conditions and possesses a wide dynamic range for output power variations. 6 refs., 8 figs

  7. Installation and operation of the 400 kW 140 GHZ gyrotron on the MTX experiment

    International Nuclear Information System (INIS)

    This paper describes the installation and operation of the 400 kW 140 GHz gyrotron used for plasma heating on the Microwave Tokamak Experiment (MTX) at Lawrence Livermore National Laboratory (LLNL). The Varian VGT-8140 gyrotron has operated at a power level of 400 kW for 100 ms in conjunction with MTX plasma shots. The gyrotron system is comprised of a high voltage (- 80 kV) modulated power supply, a multistation CAMAC computer control, a 5-tesla superconducting magnet, a series of conventional copper magnets, a circulating fluorinert (FC75) window cooling system, a circulating oil cooling system, a water cooling system, and microwave frequency and power diagnostics. Additionally, a Vlasov launcher is used to convert the gyrotron TE 15,2 mode to a Gaussian beam. Two versions of the Vlasov launcher have been used on the gyrotron, one version designed by LLNL and one version designed by the Japan Atomic Energy Research Institute (JAERI). The Varian VGT-8140 gyrotron has been installed on the MTX tokamak experiment to provide electron cyclotron resonant heating (ECRH) of the tokamak plasma. The gyrotron has been operated with the tokamak for periods as long as 100 ms at power levels of 400 kW. he gyrotron will also be used as the RF driver for the intense microwave prototype (IMP) wiggler associated with the electron test accelerator (ETA). In this configuration, the IMP wiggler will produce multigigawatt, 140 GHz, 50-ns pulses at a 5-kHz repetition rate. The plasma heating efficiency of the long RF pulse from the gyrotron can then be compared with the higher power but shorter RF pulses from the wiggler. The M2 mirror can be reversed to determine whether the gyrotron microwave beam or the IMP wiggler microwave beam is directed into the MTX tokamak. When the IMP wiggler is in operation, the gyrotron will be used as the master oscillator to drive the wiggler

  8. Experimental results of the 1 MW, 140 GHz, CW gyrotron for W7-X

    International Nuclear Information System (INIS)

    A 10 MW ECRH system will be provided by FZK in collaboration with several European associations for the stellarator W7-X. The RF power will be delivered by 10 gyrotrons operating at 140 GHz in CW with 1 MW each. The development of this gyrotron has been performed within a European collaboration in an industrial frame. Two R and D tubes have been built, up to know one serial tube has been passed the acceptance tests. The design of the gyrotron will be described and short pulse and long pulse results of the first serial gyrotron will be discussed. This gyrotron has been successfully operated at more then 900 kW with a pulse length of 30 min. (author)

  9. 140 GHz high-power gyrotron development for the stellarator W7-X

    International Nuclear Information System (INIS)

    Electron cyclotron resonance heating (ECRH) has proven to be one of the most attractive heating schemes for stellarators. Therefore, ECRH was chosen to be the main heating method for the Wendelstein 7-X stellarator (W7-X) now under construction at IPP Greifswald, Germany. A 10 MW ECRH system with continuous wave (CW) possibilities, operating at 140 GHz will be built up to meet the scientific goals of the stellarator. Two prototype gyrotrons with an output power of 1 MW were developed in collaboration between European research laboratories and European industry (Thales Electron Devices, France). The gyrotrons are equipped with a single-stage depressed collector, an optimised quasi-optical mode converter and a CVD-diamond window. The prototypes have been successfully tested at FZK. With the second one, an output power of 0.89 MW at a pulse duration of 3 min and an output power of 0.54 MW for about 15 min have been obtained

  10. Installation and operation of the 400 kW 140 GHz gyrotron on the MTX experiment

    International Nuclear Information System (INIS)

    This paper describes the installation and operation of the 400 kW 140 GHz gyrotron used for plasma heating on the Microwave Tokamak Experiment (MTX) at Lawrence Livermore National Laboratory (LLNL). The Varian VGT-8140 gyrotron has operated at a power level of 400 kW for 100 ms in conjunction with MTX plasma shots. The gyrotron system is comprised of a high voltage (-80 kV) modulated power supply, a multistation CAMAC computer control, a 5-tesla superconducting magnet, a series of conventional copper magnets, a circulating fluorinert (FC75) window cooling system, a circulating oil cooling system, a water cooling system, and microwave frequency and power diagnostics. Additionally, a Vlasov launcher is used to convert the gyrotron TE 15,2 mode to a Gaussian beam. Two versions of the Vlasov launcher have been used on the gyrotron, one version designed by LLNL and one version designed by the Japan Atomic Energy Research Institute (JAERI). The Gaussian beam from the Vlasov launcher is transported to the MTX tokamak by a series of 5 mirrors in a 35-meter-long, high-efficiency, quasioptical beam transport system. A twist polarizer is built into one of the mirrors to adjust for horizontal polarization in the tokamak. No windows are used between the Vlasov reflector and the MTX tokamak. A laser alignment system is used to perform the initial system alignment. A summary of the design and operating characteristics of each of these systems is included. Also included is a summary of the system operation and performance

  11. Experimental results of the 140 GHz, 1 MW long-pulse gyrotron for W7-X

    Science.gov (United States)

    Koppenburg, K.; Arnold, A.; Borie, E.; Dammertz, G.; Giguet, E.; Heidinger, R.; Illy, S.; Kuntze, M.; Le Cloarec, G.; Legrand, F.; Leonhardt, W.; Lievin, C.; Neffe, G.; Piosczyk, B.; Schmid, M.; Thumm, M.

    2003-02-01

    Gyrotrons at high frequency with high output power are mainly developed for microwave heating and current drive in plasmas for thermonuclear fusion. For the stellarator Wendelstein 7-X now under construction at IPP Greifswald, Germany, a 10 MW ECRH system is foreseen. A 1 MW, 140 GHz long-pulse gyrotron has been designed and a pre-prototype (Maquette) has been constructed and tested in an European collaboration between FZK Karlsruhe, CRPP Lausanne, IPF Suttgart, IPP Greifswald, CEA Cadarache and TED Vélizy [1]. The cylindrical cavity is designed for operating in the TE28,8 mode. It is a standard tapered cavity with linear input downtaper and a non-linear uptaper. The diameter of the cylindrical part is 40.96 mm. The transitions between tapers and straight section are smoothly rounded to avoid mode conversion. The TE28,8-cavity mode is transformed to a Gaussian TEM0,0 output mode by a mode converter consisting of a rippled-wall waveguide launcher followed by a three mirror system. The output window uses a single, edge cooled CVD-diamond disk with an outer diameter of 106 mm, a window aperture of 88 mm and a thickness of 1.8 mm corresponding to four half wavelengths. The collector is at ground potential, and a depression voltage for energy recovery can be applied to the cavity and to the first two mirrors. Additional normal-conducting coils are employed to the collector in order to produce an axial magnetic field for sweeping the electron beam with a frequency of 7 Hz. A temperature limited magnetron injection gun without intermediate anode ( diode type ) is used. In short pulse operation at the design current of 40 A an output power of 1 MW could be achieved for an accelerating voltage of 82 kV without depression voltage and with a depression voltage of 25 kV an output power of 1.15 MW at an accelerating voltage of 84 kV has been measured. For these values an efficiency of 49% was obtained. At constant accelerating voltages, the output power did not change up to

  12. Experimental results of the 1 MW, 140 GHz, CW gyrotron for W7-X

    International Nuclear Information System (INIS)

    For the stellarator Wendelstein 7-X now under construction at IPP Greifswald, Germany, a 10 MW ECRH system is foreseen. A European collaboration has been established between Forschungszentrum Karlsruhe (FZK), IPP Garching/Greifswald, IPF Stuttgart, CRPP Lausanne, CEA Cadarache and TED Velizy, to develop and build the 10 gyrotrons each with an output power of 1 MW for continuous wave (CW) operation. The dependence of the output power and efficiency of the first series tube versus the beam current will be shown in short pulse operation (without depressed collector) and in CW operation (up to 30 minutes, depressed collector operation). RF-field measurements have been performed in order to characterise the output field of the gyrotron and to minimise losses during the transmission to the W7-X device. Several parameters have been optimised (e.g. beam radii, magnetic field) to maximise output power and efficiency of the tube. At FZK site, long pulse tests up to 180 s have been performed (limited by the available power supply), at IPP site the pulse length could be extended to 30 min, both at a power level of 1 MW and high efficiency. (author)

  13. Gyrotrons

    International Nuclear Information System (INIS)

    The purpose of this study is to bring together some relevant ideas and developments in the field of gyrotrons. The development of the electron cyclotron resonance maser (ECRM or Gyrotron) was an important break through in microwave electronics in the 1970s. As we look to the 1980's, we find scientists channelling their collective efforts to shorten the wavelength and increase output power and efficiency, thereby yielding an important device for generating high power microwave radiation. 24 refs

  14. Status of the 140 GHz, 10 MW CW transmission system for ECRH on the stellarator W7-X

    International Nuclear Information System (INIS)

    The stellarator W7-X, which is currently under construction at IPP Greifswald, Germany, will be equipped with a 10 MW ECRH system working at 140 GHz in CW regime. The microwave power will be generated by 10 gyrotrons delivering 1 MW each and will be transmitted from the gyrotron hall to the W7-X stellarator ports via a fully optical system. The status of the construction of the transmission lines and the design of the launchers is reported. Low-power tests of a prototype system at IPF Stuttgart are reviewed. Now, the first two gyrotrons are operating at IPP Greifswald, and high-power long-pulse tests have started. Measurements on transmission performance, behaviour of the water-cooled mirrors under thermal and microwave loads as well as alignment issues, characteristics of directional couplers, calorimetric loads, and other diagnostics are discussed

  15. Development and Preliminary Commissioning Results of a Long Pulse 140 GHz ECRH System on EAST Tokamak (Invited)

    Science.gov (United States)

    Xu, Handong; Wang, Xiaojie; Liu, Fukun; Zhang, Jian; Huang, Yiyun; Shan, Jiafang; Wu, Dajun; Hu, Huaichuan; Li, Bo; Li, Miaohui; Yang, Yong; Feng, Jianqiang; Xu, Weiye; Tang, Yunying; Wei, Wei; Xu, Liqing; Liu, Yong; Zhao, Hailin; Lohr, J.; A. Gorelov, Y.; P. Anderson, J.; Ma, Wendong; Wu, Zege; Wang, Jian; Zhang, Liyuan; Guo, Fei; Sun, Haozhang; Yan, Xinsheng; East Team

    2016-04-01

    A long pulse electron cyclotron resonance heating (ECRH) system has been developed to meet the requirements of steady-state operation for the EAST superconducting tokamak, and the first EC wave was successfully injected into plasma during the 2015 spring campaign. The system is mainly composed of four 140 GHz gyrotron systems, 4 ITER-Like transmission lines, 4 independent channel launchers and corresponding power supplies, a water cooling, control & inter-lock system etc. Each gyrotron is expected to deliver a maximum power of 1 MW and be operated at 100-1000 s pulse lengths. The No.1 and No.2 gyrotron systems have been installed. In the initial commissioning, a series of parameters of 1 MW 1 s, 900 kW 10 s, 800 kW 95 s and 650 kW 753 s have been demonstrated successfully on the No.1 gyrotron system based on calorimetric dummy load measurements. Significant plasma heating and MHD instability suppression effects were observed in EAST experiments. In addition, high confinement (H-mode) discharges triggered by ECRH were obtained. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2011GB102000, 2012GB103000 and 2015GB103000)

  16. Development in Russia of high power gyrotrons for fusion

    International Nuclear Information System (INIS)

    Full text: Electron cyclotron systems of fusion installations are based on powerful millimetre wave sources - gyrotrons, which are capable to produce now microwave power up to 1 MW in very long (hundreds of seconds) pulses. The paper presents the latest achievements in development at IAP/GYCOM of MW power level gyrotrons for fusion installations. Among them are a new versions of 170 GHz gyrotron for ITER and multi-frequency (105-140 GHz) gyrotron for Asdex-Up. The gyrotrons are equipped with diamond CVD windows and depressed collectors. The most efforts were spent for development of ITER gyrotron. The tests are carried out at specially prepared test stand in Kurchatov Institute. The following gyrotron output parameters were demonstrated so far in many pulses: 1MW/30 sec and 0.64 MW/300 sec. Also a gyrotron with a higher power -1.5 MW was designed and tested in short pulses. The tests continue. In two tested long-pulse dual-frequency gyrotrons, power in the output Gaussian beam exceeding 0.9MW at 140GHz and 0.7MW at 105GHz was attained at specified 10-s pulse duration. The multi-frequency gyrotron should operate at least at four frequencies in the frequency range 105GHz-140 GHz. Two window concepts for the gyrotron are considered: Brewster window and two-disc adjustable window. Last years significant efforts were done by IAP/GYCOM in order to solve the whole scope of problems associated with the use of CVD diamond windows in gyrotrons: growing of discs, their cutting and polishing, and then high-temperature brazing and mounting to a tube. Two setups for growing diamond discs have been put into operation. The first discs grown at IAP have acceptable mechanical and electrical parameters. The IAP/GYCOM discs have been successfully brazed at near 800 deg. C temperature to metal constructions and tested with high-power gyrotrons. (author)

  17. Results of 170 GHz gyrotron tests

    International Nuclear Information System (INIS)

    During the last few years the development of 170 GHz gyrotron for ITER have been under way. Sketchy description of experiment and test results of an improved design gyrotron with a depressed collector, are reported. The analysis of the phenomena causing the destruction of the output window is submitted. The projects for the following experiments are presented. The new 170 GHz/1 MW/50%/CW gyrotron with depressed collector and CVD diamond window was developed by GYCOM. This gyrotron was tested with BN window and then with diamond window. The gyrotron testing showed that practically all ITER requirements are satisfied except of pulse duration limited to that time by brick load arcing. Imperfection of arc protection system gave the possibility for arc-plasma to come to the window and destroy it. New loads have been created and tested at 140 GHz, with output gyrotron power Phf = 820 kW and the pulse duration T = 3.5 s. A new version of protection system has been developed and tested in experiment. The next gyrotron with modified electron gun has been manufactured. After first stage test, BN window will be replaced with new CVD diamond unit, which is assembling now. Testing of this gyrotron is planned to carry out in May 2002. (authors)

  18. A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies

    Science.gov (United States)

    Smith, Albert A.; Corzilius, Björn; Bryant, Jeffrey A.; DeRocher, Ronald; Woskov, Paul P.; Temkin, Richard J.; Griffin, Robert G.

    2012-10-01

    We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz (1H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 GHz. A coiled TE011 resonator acts as both an NMR coil and microwave resonator, and a double balanced (1H, 13C) radio frequency circuit greatly stabilizes the NMR performance. A new 140 GHz microwave bridge has also been developed, which utilizes a four-phase network and ELDOR channel at 8.75 GHz, that is then multiplied and mixed to obtain 140 GHz microwave pulses with an output power of 120 mW. Nutation frequencies obtained are as follows: 6 MHz on S = 1/2 electron spins, 100 kHz on 1H, and 50 kHz on 13C. We demonstrate basic EPR, ELDOR, ENDOR, and DNP experiments here. Our solid effect DNP results demonstrate an enhancement of 144 and sensitivity gain of 310 using OX063 trityl at 80 K and an enhancement of 157 and maximum sensitivity gain of 234 using Gd-DOTA at 20 K, which is significantly better performance than previously reported at high fields (⩾3 T).

  19. Start currents in an overmoded gyrotron

    Science.gov (United States)

    Yeddulla, M.; Nusinovich, G. S.; Antonsen, T. M.

    2003-11-01

    High-power long-pulse millimeter-wave gyrotrons operate in high-order modes. The spectral density of these modes is very high. Therefore, self-excitation conditions can be fulfilled for several modes simultaneously. Correspondingly, in order to determine which mode will be excited first in such a device, the starting currents of competing modes should be calculated much more accurately than in gyrotrons with a rarer spectrum. In the present paper, an existing linear theory is generalized to take into account effects of magnetic field tapering, cavity profile, finite beam thickness, velocity spread and axially dependent beam coupling to the fields of competing modes. Starting currents are calculated for the operating and the most dangerous competing mode in a 140 GHz gyrotron, which is under development at Communication and Power Industries. Calculations show that the radial position of the electron beam plays a critical role in deciding which mode dominates the mode competition.

  20. Demonstration of a 140-GHz 1-kW Confocal Gyro-Traveling-Wave Amplifier

    OpenAIRE

    Joye, Colin D.; Shapiro, Michael A.; Sirigiri, Jagadishwar R.; Temkin, Richard J.

    2009-01-01

    The theory, design, and experimental results of a wideband 140-GHz 1-kW pulsed gyro-traveling-wave amplifier (gyro-TWA) are presented. The gyro-TWA operates in the HE06 mode of an overmoded quasi-optical waveguide using a gyrating electron beam. The electromagnetic theory, interaction theory, design processes, and experimental procedures are described in detail. At 37.7 kV and a 2.7-A beam current, the experiment has produced over 820 W of peak power with a –3-dB bandwidth of 0.8 GHz and a li...

  1. Millimeter-wave, megawatt gyrotron development for ECR (electron cyclotron resonance) heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Jory, H.; Felch, K.; Hess, C.; Huey, H.; Jongewaard, E.; Neilson, J.; Pendleton, R.; Tsirulnikov, M. (Varian Associates, Inc., Palo Alto, CA (USA))

    1990-09-17

    To address the electron cyclotron heating requirements of planned fusion experiments such as the International Thermonuclear Experimental Reactor (ITER) and the Compact Ignition Tokamak (CIT), Varian is developing gyrotrons at frequencies ranging from 100--300 GHz with output power capabilities up to 1 MW CW. Experimental gyrotrons have been built at frequencies between 100--140 GHz, and a study program has addressed the critical elements of designing 280--300 GHz gyrotrons capable of generating CW power levels up to 1 MW. Initial test vehicles at 140 GHz have utilized TE{sub 15,2,1} interaction cavities, and have been designed to generate short-pulse (up to 20 ms) power levels of 1 MW and up to 400 kW CW. Recently, short-pulse power levels of 1040 kW at 38% efficiency have been obtained and average powers of 200 kW have been achieved. Long-pulse operation has been extended to pulse durations of 0.5 seconds at power levels of 400 kW. Gyrotron oscillators capable of generating output powers of 500 kW CW at a frequency of 110 GHz have recently been designed and a prototype is currently being tested. Design work for a 1 MW CW gyrotron at 110 GHz, is in progress. The 1 MW CW tube will employ an output coupling approach where the microwave output is separated from the microwave output. 15 refs., 10 figs., 3 tabs.

  2. Experimental results of series gyrotrons for the stellarator W7-X

    International Nuclear Information System (INIS)

    A powerful ECRH system with 10 MW RF power at 140 GHz and CW operation is foreseen for the stellarator W7-X, being under construction at IPP Greifswald. The RF power will be delivered by 10 gyrotrons, each capable of 1 MW, CW. Nine gyrotrons are being manufactured by Thales Electron Devices (TED), Velizy, France, one gyrotron was produced by CPI, Palo Alto, CA. Testing of the TED gyrotrons is performed at the test stand at FZK (pulse duration 3 min) and the final tests are performed at IPP (pulse length 30 min). Both, the first TED series gyrotron and the CPI gyrotron have passed the acceptance tests successfully. The acceptance tests of the TED series gyrotrons are ongoing. The RF output beam quality of all tubes tested so far is at a constant high level of about 97% in the Gaussian beam. In short pulse operation the gyrotrons have achieved the specified parameters. However, for long pulse operation the performance decreases due to the occurrence of parasitic oscillations which are assumed to be excited by the electron beam in the beam tunnel close to the cavity. Experimental results of this effect and possible modifications of the beam tunnel geometry will be discussed. (author)

  3. Gyrotron Development in the EU for Present Fusion Experiments and for ITER

    International Nuclear Information System (INIS)

    The long term strategy of the EU in the field of gyrotrons in fusion plasma applications is based on two approaches: R and D in laboratories to develop advanced concepts and industrial development of state-of-the-art tubes for use in present experiments like TCV, Tore Supra (118 GHz, 0.5 MW, CW) and W7-X (140 GHz, 1 MW, CW). The results from these two approaches are then applied to the development of a coaxial cavity gyrotron operating at 170 GHz and delivering 2 MW-CW for the electron cyclotron wave system of ITER. This paper will recall the main achievements of this program and will outline the present status of the 170 GHz coaxial cavity gyrotron development

  4. THE CONTRIBUTION OF RADIO GALAXY CONTAMINATION TO MEASUREMENTS OF THE SUNYAEV-ZEL'DOVICH DECREMENT IN MASSIVE GALAXY CLUSTERS AT 140 GHz WITH BOLOCAM

    Energy Technology Data Exchange (ETDEWEB)

    Sayers, J.; Mroczkowski, T.; Czakon, N. G.; Golwala, S. R.; Downes, T. P.; Muchovej, S. J. C.; Siegel, S. [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Mantz, A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ameglio, S.; Pierpaoli, E.; Shitanishi, J. A. [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089 (United States); Koch, P. M.; Lin, K.-Y.; Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Molnar, S. M. [LeCosPA Center, National Taiwan University, Taipei 10617, Taiwan (China); Moustakas, L., E-mail: jack@caltech.edu [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States)

    2013-02-20

    We describe in detail our characterization of the compact radio source population in 140 GHz Bolocam observations of a set of 45 massive galaxy clusters. We use a combination of 1.4 and 30 GHz data to select a total of 28 probable cluster-member radio galaxies and also to predict their 140 GHz flux densities. All of these galaxies are steep-spectrum radio sources and they are found preferentially in the cool-core clusters within our sample. In particular, 11 of the 12 brightest cluster-member radio sources are associated with cool-core systems. Although none of the individual galaxies are robustly detected in the Bolocam data, the ensemble-average flux density at 140 GHz is consistent with, but slightly lower than, the extrapolation from lower frequencies assuming a constant spectral index. In addition, our data indicate an intrinsic scatter of {approx_equal} 30% around the power-law extrapolated flux densities at 140 GHz, although our data do not tightly constrain this scatter. For our cluster sample, which is composed of high-mass and moderate-redshift systems, we find that the maximum fractional change in the Sunyaev-Zel'dovich signal integrated over any single cluster due to the presence of these radio sources is {approx_equal} 20%, and only {approx_equal} 1/4 of the clusters show a fractional change of more than 1%. The amount of contamination is strongly dependent on cluster morphology, and nearly all of the clusters with {>=}1% contamination are cool-core systems. This result indicates that radio contamination is not significant compared with current noise levels in 140 GHz images of massive clusters and is in good agreement with the level of radio contamination found in previous results based on lower frequency data or simulations.

  5. Optimization of oversized corrugated waveguide bends for higher-order TE0n-modes at 140 GHz

    International Nuclear Information System (INIS)

    Oversized corrugated 900 waveguide bends with a waveguide diameter of 27.79 mm were optimized for TE0n (n = 3...6) transmission lines to transmit power of about 200 kW for Electron-Cyclotron-Resonance-Heating of plasmas in thermonuclear fusion research at a frequency of 140 GHz. The corrugation removes the degeneracy of the mode pairs TE0n/TM1n. The bends were optimized by numerical integration of the coupled-mode differential equations for six coupled modes: TE0n, HE1n, EH1n, EH1,n+1, HE2n and EH2n. During the optimization procedure three parameters were varied: curvature distribution, corrugation depth and arc length. Following curvature distributions were studied: sine-sine-squared, triangular and specific Fourier series. The last one was found to be the best. The optimum corrugation depth increases with increasing mode number n, whereas the arc length decreases. It was found, that a small elliptical deformation of less than 0.04 mm has a negligible influence on TE03- and TE04-bends. In the case of TE05- and TE06-bends the arc length must be increased in order to maintain a pure output mode. (orig.)

  6. Design considerations in achieving 1 MW CW operation with a whispering-gallery-mode gyrotron

    International Nuclear Information System (INIS)

    Varian is developing high-power, CW gyrotrons at frequencies in the range 100 GHz to 150 GHz, for use in electron cyclotron heating applications. Early test vehicles have utilized a TE15,2,1 interaction cavity, have achieved short-pulse power levels of 820 kW and average power levels of 80 kW at 140 GHz. Present tests are aimed at reaching 400 kW under CW operating conditions and up to 1 MW for short pulse durations. Work is also underway on modifications to the present design that will enable power levels of up to 1 MW CW to be achieved. 7 refs., 2 figs

  7. Investigation of a 140 GHz gryo-backward wave oscillator and a 95 GHz gyro-traveling wave

    International Nuclear Information System (INIS)

    There is current interest in developing a high-power source of continuously tunable millimeter wave radiation as a RF driver for high-power gyrotron, CARM, or FEL amplifiers. The gyrotron backward wave oscillator is a voltage-tunable fast-wave device that can satisfy these requirements. This thesis reports on the design and experimental investigation of a 130--145 GHz gyrotron backward wave oscillator Novel operating features of this design include the use of a 80-kV, 6.2-A Pierce-wiggler electron beam source, a broadband motheye window and an overmoded TE1,2 cylindrical interaction waveguide. Although this device has demonstrated voltage-tunable operation over the design range in the TE1,2 mode, the frequency tuning is not continuous, output powers were low and full-beam transmission through the interaction region was not possible. Simulations indicate that the beam has very high velocity spread induced by space charge forces in the compression region. After increasing the diameter of the beam tunnel to achieve full transmission, the TE1,2 was not found. It is felt that the scraping off of the beam edge in the initial experiments allowed a better quality beam to enter the interaction region and inhibited coupling into competing forward wave modes. The need for radar systems with greater resolution has led to renewed interest in the development of efficient high-power amplifiers at 95 GHz. Current sources are limited to 6--8 kW of output power due to ohmic loading on the slow-wave circuit. A gyrotron traveling wave tube amplifier is capable of efficient operation over a wide bandwidth with the added attraction of low ohmic loading on the smooth fast-wave circuit. This thesis reports of the design a 95-GHz gyrotron traveling wave tube amplifier that is capable of high power (125 kW), high gain (38 dB), large bandwidth > 5 GHz and high efficiencies (> 30%)

  8. High-harmonic gyrotrons

    Science.gov (United States)

    McDermott, D. B.; Luhmann, N. C., Jr.

    1984-08-01

    There is currently much interest in the development of moderate to high power (1 kW - 1 MW) millimeter wave sources. Considered applications are mainly related to radar and communication systems. There are, however, also applications in plasma diagnostics, heating, and the nondestructive testing of dielectrics. The dominant source of high-power, high-frequency radiation has become the gyrotron. Jory et al. (1983) have reported operation of a 60 GHz, CW gyrotron, producing output powers in excess of 200 kW. High power, compact submillimeter-wave sources have become possible by making use of the concept of a high-harmonic gyrotron, in which the magnetic field can be reduced by an order of magnitude. Attention is given to synchronism, negative-mass instability, energy requirements, oscillators, efficiency, high power, dielectric loading, the peniotron, and amplifiers.

  9. An integrated gyrotron controller

    Energy Technology Data Exchange (ETDEWEB)

    Michel, Georg, E-mail: michel@ipp.mpg.de; Sachtleben, Juergen

    2011-10-15

    The ECRH system of W7-X is composed of 10 independent gyrotron modules. Each module consists of one gyrotron and its peripherals such as power supplies, cooling plants and distributed PLC systems. The fast real-time control functions such as the timing of the two high voltage supplies, trigger pulses, protection, modulation and communication with the central control of W7-X, is implemented in an integrated controller which is described in this paper. As long-term maintainability and sustainability are important for nuclear fusion experiments, the choice fell on an FPGA-based design which is exclusively based on free (as in 'freedom') software and configuration code. The core of the controller consists of a real-time Java virtual machine (JVM) that provides the TCP-IP connectivity as well as more complicated control functions, and which interacts with the gyrotron-specific hardware. Both the gyrotron-specific hardware and the JVM are implemented on the same FPGA, which is the main component of the controller. All 10 controllers are currently completed and operational. All parameters and functions are accessible via Ethernet. Due to the open, FPGA-based design, most hardware modifications can be made via the network as well. This paper discusses the capabilities of the controllers and their integration into the central W7-X control.

  10. State-of-the-art and recent developments of high-power gyrotron oscillators

    Science.gov (United States)

    Thumm, Manfred

    1999-05-01

    Gyrotron oscillators (gyromonotrons) are mainly used as high-power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. High unit power and high efficiency single-mode CW gyrotrons with conventional cylindrical (1 MW) and advanced coaxial (2 MW) cavities are worldwide under development. 118 GHz, 140 GHz and 170 GHz conventional cavity gyrotrons with output power Pout≈0.5 MW, pulse length τ≈5.0 s and efficiency η≈35% are commercially available. Advanced internal quasi-optical mode converters generate linearly polarized output wave beams from the high-order cavity modes (e.g., TE22,6) with efficiencies of 90-95% and separate the millimeter-wave beam from the electron beam, thus allowing the use of large CW-relevant depressed collectors for energy recovery. Overall efficiencies between 50 and 60% have been already achieved at JAERI, FZK, and GYCOM employing single-stage depressed collectors (SDC). First successful experiments at FZK employing a broadband Brewster window gave up to 1.5 MW output power at around 50% efficiency (SDC) for all operating mode series in the frequency range from 114 to 166 GHz (frequency tuning in 3.7 GHz steps by variation of the magnetic field strength in the cavity). Gyrotrons with advanced coaxial cavities designed for operation in the TE28,16 and TE31,17 modes at 140 and 165 GHz, respectively, are under development and test at IAP Nizhny Novgorod and FZK Karlsruhe. A maximum output power of 1.7 MW has been measured at 165 GHz with an efficiency of 35.2% (SDC, FZK). Cryogenically edge-cooled single-disk sapphire (T=77 K) and Au-doped silicon (T=230 K) windows as well as CVD-diamond windows with water edge-cooling at room temperature are under investigation in order to solve the window problem. Commercial CVD-diamond disks will easily allow the transmission of 2 MW power level at 170 GHz, CW. Bonding and

  11. State-of-the-art and recent developments of high-power gyrotron oscillators

    International Nuclear Information System (INIS)

    Gyrotron oscillators (gyromonotrons) are mainly used as high-power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. High unit power and high efficiency single-mode CW gyrotrons with conventional cylindrical (1 MW) and advanced coaxial (2 MW) cavities are worldwide under development. 118 GHz, 140 GHz and 170 GHz conventional cavity gyrotrons with output power Pout≅0.5 MW, pulse length τ≅5.0 s and efficiency η≅35% are commercially available. Advanced internal quasi-optical mode converters generate linearly polarized output wave beams from the high-order cavity modes (e.g., TE22,6) with efficiencies of 90-95% and separate the millimeter-wave beam from the electron beam, thus allowing the use of large CW-relevant depressed collectors for energy recovery. Overall efficiencies between 50 and 60% have been already achieved at JAERI, FZK, and GYCOM employing single-stage depressed collectors (SDC). First successful experiments at FZK employing a broadband Brewster window gave up to 1.5 MW output power at around 50% efficiency (SDC) for all operating mode series in the frequency range from 114 to 166 GHz (frequency tuning in 3.7 GHz steps by variation of the magnetic field strength in the cavity). Gyrotrons with advanced coaxial cavities designed for operation in the TE28,16 and TE31,17 modes at 140 and 165 GHz, respectively, are under development and test at IAP Nizhny Novgorod and FZK Karlsruhe. A maximum output power of 1.7 MW has been measured at 165 GHz with an efficiency of 35.2% (SDC, FZK). Cryogenically edge-cooled single-disk sapphire (T=77 K) and Au-doped silicon (T=230 K) windows as well as CVD-diamond windows with water edge-cooling at room temperature are under investigation in order to solve the window problem. Commercial CVD-diamond disks will easily allow the transmission of 2 MW power level at 170 GHz, CW. Bonding and

  12. Gyrotron oscillators for fusion heating

    International Nuclear Information System (INIS)

    Recent experiments have been performed to determine the ultimate power capability of a 28 GHz 200 kW CW gyrotron design. A power output of 342 kW CW was measured in these tests with an efficiency of 37%. Progress in the development of 60 GHz 200 kW pulsed and CW gyrotrons is discussed. An output of 200 kW with 100 msec pulse length has been achieved with the pulsed design

  13. Design of an ultra-broadband single-disk output window for a frequency step-tunable 1 MW gyrotron

    International Nuclear Information System (INIS)

    Output window design is one of the key issues to realize broadband output of a multi-frequency gyrotron. Corresponding to the recent development of a frequency step-tunable 1 MW gyrotron at Forschungszentrum Karlsruhe (FZK), this paper reports about a newly designed ultra-broadband CVD-diamond disk Brewster window. The thickness of the disk and the geometry of the window unit have been optimized to get low power reflection over a broadband incident angle range around the Brewster angle at different operating frequencies. Detailed calculations of mm-wave transmission characteristics for this Brewster window have been performed for all the considered operation modes from TE17,6 at 105 GHz up to TE23,8 at 143 GHz, and for thickness of the disk from 1.5 to 2.0 mm. Calculations show if one prefers to place the low reflection area in the middle of the discussed frequency range (120-130 GHz), the thickness of 1.6 mm is near optimum and its -20 dB bandwidth angle is more than 30o. For operation near 105 and 140 GHz, a 1.9 mm disk is preferable and its -20 dB bandwidth angle is around 30o

  14. Advances in high power calorimetric matched loads for short pulses and CW gyrotrons

    International Nuclear Information System (INIS)

    ) and the CW version at 2 MW, 170 GHz, are described in the paper. High power tests on short-pulse loads have been done using a double frequency gyrotron, 105 GHz/600 kW for 0.5 s and 140 GHz/800 kW for 1 s. Also a method for emulating 2 MW conditions while using 1 MW gyrotron has been applied to test the load to be used for the European 2 MW coaxial cavity gyrotron development programme

  15. Systematic Observation of Time-Dependent Phenomena in the RF Output Spectrum of High Power Gyrotrons

    Directory of Open Access Journals (Sweden)

    Kern Stefan

    2012-09-01

    Full Text Available At IHM/KIT, high power gyrotrons with conventional cavity (e.g. 1 MW CW at 140 GHz for the stellarator Wendelstein 7-X and coaxial cavity (2 MW shortpulse at 170 GHz for ITER for fusion applications are being developed and verified experimentally. Especially with respect to the problem of parasitic RF oscillations in the beam tunnel of some W7-X tubes, investigations of the gyrotron RF output spectrum have proved to be a valuable source of diagnostic information. Signs of transient effects in millisecond pulses, like frequency switching or intermittent low-frequency modulation, have indicated that truly time-dependent measurements with high frequency resolution and dynamic range could give deeper insight into these phenomena. In this paper, an improved measurement system is presented, which employs a fast oscilloscope as receiver. Shorttime Fourier transform (STFT is applied to the time-domain signal, yielding time-variant spectra with frequency resolutions only limited by acquisition length and STFT segmentation choice. Typical reasonable resolutions are in the range of 100 kHz to 10 MHz with a currently memory-limited maximum acquisition length of 4 ms. A key feature of the system consists in the unambiguity of frequency measurement: The system receives through two parallel channels, each using a harmonic mixer (h = 9 – 12 to convert the signal from RF millimeter wave frequencies (full D-Band, 110 – 170 GHz to IF (0 – 3 GHz. For each IF output signal of each individual mixer, injection side and receiving harmonic are initially not known. Using accordingly determined LO frequencies, this information is retrieved from the redundancy of the channels, yielding unambiguously reconstructed RF spectra with a total span of twice the usable receiver IF bandwidth, up to ≈ 6 GHz in our case. Using the system, which is still being improved continuously, various transient effects like cavity mode switching, parasitic oscillation frequency variation

  16. Systematic Observation of Time-Dependent Phenomena in the RF Output Spectrum of High Power Gyrotrons

    Science.gov (United States)

    Schlaich, Andreas; Gantenbein, Gerd; Kern, Stefan; Thumm, Manfred

    2012-09-01

    At IHM/KIT, high power gyrotrons with conventional cavity (e.g. 1 MW CW at 140 GHz for the stellarator Wendelstein 7-X) and coaxial cavity (2 MW shortpulse at 170 GHz for ITER) for fusion applications are being developed and verified experimentally. Especially with respect to the problem of parasitic RF oscillations in the beam tunnel of some W7-X tubes, investigations of the gyrotron RF output spectrum have proved to be a valuable source of diagnostic information. Signs of transient effects in millisecond pulses, like frequency switching or intermittent low-frequency modulation, have indicated that truly time-dependent measurements with high frequency resolution and dynamic range could give deeper insight into these phenomena. In this paper, an improved measurement system is presented, which employs a fast oscilloscope as receiver. Shorttime Fourier transform (STFT) is applied to the time-domain signal, yielding time-variant spectra with frequency resolutions only limited by acquisition length and STFT segmentation choice. Typical reasonable resolutions are in the range of 100 kHz to 10 MHz with a currently memory-limited maximum acquisition length of 4 ms. A key feature of the system consists in the unambiguity of frequency measurement: The system receives through two parallel channels, each using a harmonic mixer (h = 9 - 12) to convert the signal from RF millimeter wave frequencies (full D-Band, 110 - 170 GHz) to IF (0 - 3 GHz). For each IF output signal of each individual mixer, injection side and receiving harmonic are initially not known. Using accordingly determined LO frequencies, this information is retrieved from the redundancy of the channels, yielding unambiguously reconstructed RF spectra with a total span of twice the usable receiver IF bandwidth, up to ≈ 6 GHz in our case. Using the system, which is still being improved continuously, various transient effects like cavity mode switching, parasitic oscillation frequency variation, and lowfrequency

  17. Analytic theory of the gyrotron

    International Nuclear Information System (INIS)

    An analytic theory is derived for a gyrotron operating in the linear gain regime. The gyrotron is a coherent source of microwave and millimeter wave radiation based on an electron beam emitting at cyclotron resonance Ω in a strong, uniform magnetic field. Relativistic equations of motion and first order perturbation theory are used. Results are obtained in both laboratory and normalized variables. An expression for cavity threshold gain is derived in the linear regime. An analytic expression for the electron phase angle in momentum space shows that the effect of the RF field is to form bunches that are equal to the unperturbed transit phase plus a correction term which varies as the sine of the input phase angle. The expression for the phase angle is plotted and bunching effects in and out of phase (0 and -π) with respect to the RF field are evident for detunings leading to gain and absorption, respectively. For exact resonance, field frequency ω = Ω, a bunch also forms at a phase of -π/2. This beam yields the same energy exchange with the RF field as an unbunched, (nonrelativistic) beam. 6 refs., 10 figs

  18. Linear and nonlinear analysis of a gyro-peniotron oscillator and study of start-up scenario in a high order mode gyrotron

    Science.gov (United States)

    Yeddulla, Muralidhar

    linear theory of gyrotrons is extended to include effects of magnetic field tapering, cavity wall profile, finite beam thickness, velocity spread and axially dependent beam coupling to the fields of competing modes. Starting currents are calculated for the operating and the most dangerous competing mode in a 140 GHz gyrotron, which was developed at Communications and Power Industries (CPI). Start-up scenario of this device is also studied using the non-stationary code MAGY, which is a tool for modeling slow and fast microwave sources.

  19. Recent result of gyrotron operation in NIFS

    Directory of Open Access Journals (Sweden)

    Ito Satoshi

    2015-01-01

    Full Text Available In the last Large Helical Device (LHD experimental campaign, a 154GHz gyrotron which had been conditioned to generate 1 MW/2 s, 0.5 MW/CW was installed for LHD experiments. Four high power gyrotrons (three-77 GHz/1~1.5 MW and one-154 GHz/1 MW and a CW gyrotron (84 GHz/0.2 MW are ready. Our experiment requires high energy and various injection patterns for Electron Cyclotron Resonance Heating (ECRH. Higher individual injection power and various injection patterns, we developed a power enhancement method by stepped anode acceleration voltage control and operated the gyrotron in the hard excitation region. These operations were realized by a remote controlled waveform generator. However the oscillation map of high power or long pulse operation in the hard excitation region were limited because in order to achieve the hard excitation region by the anode voltage control one must pass through the high anode current phase within a time short enough that the anode or the anode power supply is not overloaded. This limitation becomes more critical when the gyrotron beam current is increased in order to increase the output power. In the long pulse operation it was impossible to reach the hard excitation region in a low beam current (<10A.

  20. The 110 GHz Gyrotron System on DIII-D: Gyrotron Tests and Physics Results

    International Nuclear Information System (INIS)

    The DIII-D tokamak has installed a system with three gyrotrons at the 1 MW level operating at 110 GHz. Physics experiments on electron cyclotron current drive, heating, and transport have been performed. Good efficiency has been achieved both for on-axis and off-axis current drive with relevance for control of the current density profile leading to advanced regimes of tokamak operation, although there is a difference between off-axis ECCD efficiency inside and outside the magnetic axis. Heating efficiency is excellent and electron temperatures up to 10 keV have been achieved. The gyrotron system is versatile, with poloidal scan and control of the polarization of the injected rf beam. Phase correcting mirrors form a Gaussian beam and focus it into the waveguide. Both perpendicular and oblique launch into the tokamak have been used. Three different gyrotron designs are installed and therefore unique problems specific to each have been encountered, including parasitic oscillations, mode hops during modulation and polarization control problems. Two of the gyrotrons suffered damage during operations, one due to filament failure and one due to a vacuum leak. The repairs and subsequent testing will be described. The transmission system uses evacuated, windowless waveguide and the three gyrotrons have output windows of three different materials. One gyrotron uses a diamond window and generates a Gaussian beam directly. The development of the system and specific tests and results from each of the gyrotrons will be presented. The DIII-D project has committed to an upgrade of the system, which will add three gyrotrons in the 1 MW class, all using diamond output windows, to permit operation at up to ten seconds per pulse at one megawatt output for each gyrotron

  1. Calorimetric Power Measurements of the DIII-D Gyrotron System

    Science.gov (United States)

    Gorelov, I.; Lohr, J.; Callis, R. W.; Cary, W. P.; Ponce, D.; Pinsker, R. I.; Chiu, H.; Baity, F. W.

    2001-10-01

    Gyrotron power measurements are an integral part of rf experiments on DIII-D. The ECH complex at General Atomics is built up from four 110 GHz, 1 MW gyrotrons, one from Communication and Power Industry (CPI) and three from Russia's Gyrotron Company (Gycom). Power measurements are made calorimetrically using the temperature and flow measurements of the gyrotron cooling circuits. Three such circuits are measured on the Gycom gyrotrons: window, MOU and dummy load. Interior cooling circuits are additionally measured on the CPI gyrotron that are very useful when tuning for maximum power and efficiency. Calorimetric signals from each cooling circuit are acquired by computer, where the dissipated energy is calculated with a LabView program. From these calculations, total rf power and efficiency were determined. Thus, calorimetry measurements were effectuated during gyrotron operations to provide the average power of each pulse.

  2. Recent achievements on tests of series gyrotrons for W7-X and planned extension at the KIT gyrotron test facility

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, M., E-mail: martin.schmid@kit.edu [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Choudhury, A. Roy; Dammertz, G. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Erckmann, V. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Max-Planck-Institute for Plasmaphysics, Association EURATOM-IPP, Greifswald (Germany); Gantenbein, G.; Illy, S. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Jelonnek, J. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Institute of High Frequency Techniques and Electronics (IHE) (Germany); Kern, S. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Legrand, F. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Thales Electron Devices, Vélicy (France); Rzesnicki, T.; Samartsev, A. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Schlaich, A.; Thumm, M. [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute for Pulsed Power and Microwave Technology (IHM) (Germany); Institute of High Frequency Techniques and Electronics (IHE) (Germany)

    2013-10-15

    Highlights: ► Solution found to suppress parasitic beam tunnel oscillations on high power gyrotrons. ► Electron beam sweeping technique to avoid plastic deformation on collector of high power gyrotrons. ► Ongoing investigations on limitations of gyrotron efficiency. ► Upgrade of 10 MW CW modulator for gyrotrons with multistage depressed collectors. -- Abstract: Parasitic beam tunnel oscillations have been hampering the series production of gyrotrons for W7-X. This problem has now been overcome thanks to the introduction of a specially corrugated beam tunnel. Two gyrotrons equipped with the new beam tunnel have fully passed the acceptance tests. Despite excellent power capability, the expected efficiency has not yet been achieved, possibly due to the presence of parasitic oscillations suspected to be dynamic after-cavity-oscillations (ACI's) or due to insufficient electron beam quality. Both theoretical and experimental investigations on these topics are ongoing. On previous W7-X gyrotrons collector fatigue has been observed, not (yet) leading to any failures so far. The plastic deformation occurring on the collector has now been eliminated due to the strict use (on all gyrotrons) of a sweeping method which combines the conventional 7 Hz solenoid sweeping technique with a 50 Hz transverse-field sweep system. Starting in 2013, the gyrotron test facility at KIT will be enhanced, chiefly with a new 10 MW DC modulator, capable of testing gyrotrons up to 4 MW CW output power with multi-stage-depressed collectors.

  3. Recent achievements on tests of series gyrotrons for W7-X and planned extension at the KIT gyrotron test facility

    International Nuclear Information System (INIS)

    Highlights: ► Solution found to suppress parasitic beam tunnel oscillations on high power gyrotrons. ► Electron beam sweeping technique to avoid plastic deformation on collector of high power gyrotrons. ► Ongoing investigations on limitations of gyrotron efficiency. ► Upgrade of 10 MW CW modulator for gyrotrons with multistage depressed collectors. -- Abstract: Parasitic beam tunnel oscillations have been hampering the series production of gyrotrons for W7-X. This problem has now been overcome thanks to the introduction of a specially corrugated beam tunnel. Two gyrotrons equipped with the new beam tunnel have fully passed the acceptance tests. Despite excellent power capability, the expected efficiency has not yet been achieved, possibly due to the presence of parasitic oscillations suspected to be dynamic after-cavity-oscillations (ACI's) or due to insufficient electron beam quality. Both theoretical and experimental investigations on these topics are ongoing. On previous W7-X gyrotrons collector fatigue has been observed, not (yet) leading to any failures so far. The plastic deformation occurring on the collector has now been eliminated due to the strict use (on all gyrotrons) of a sweeping method which combines the conventional 7 Hz solenoid sweeping technique with a 50 Hz transverse-field sweep system. Starting in 2013, the gyrotron test facility at KIT will be enhanced, chiefly with a new 10 MW DC modulator, capable of testing gyrotrons up to 4 MW CW output power with multi-stage-depressed collectors

  4. 100 GHz, 1 MW, CW gyrotron study program. Final report

    International Nuclear Information System (INIS)

    The results of a study program to investigate the feasibility of various approaches in designing a 100 GHz, 1 MW CW gyrotron are presented. A summary is given of the possible configurations for a high average power, high frequency gyrotron, including an historical survey of experimental results which are relevant to the various approaches. A set of basic scaling considerations which enable qualitative comparisons between particular gyrotron interaction circuits is presented. These calculations are important in understanding the role of various electron beam and circuit parameters in achieving a viable gyrotron design. Following these scaling exercises, a series of design calculations is presented for a possible approach in achieving 100 GHz, 1 MW CW. These calculations include analyses of the electron gun and interaction circuit parts of the gyrotron, and a general analysis of other aspects of a high average power, high frequency gyrotron. Scalability of important aspects of the design to other frequencies is also discussed, as well as key technology issues

  5. Development of high power long pulse gyrotron for ITER

    International Nuclear Information System (INIS)

    A development of 170GHz gyrotron has been carried out as a task of ITER/EDA, and remarkable progress was obtained. Critical issues on the gyrotron development; low efficiency, high heat load at the resonator, window problem, have been solved by breakthroughs; a depressed collector, 1MW single mode oscillation with a high order mode TE31,8, and development of the diamond window gyrotron, respectively. The prototype ITER gyrotron which integrated these technologies were fabricated and tested. Up to now, the power output of 0.45MW, 8sec has been obtained with a diamond window gyrotron. These results give a clear prospect of the 1MW/CW 170GHz gyrotron. (author)

  6. Gyrotron electromagnetic wiggler for a compact free electron laser

    International Nuclear Information System (INIS)

    We have demonstrated a novel, high power (≥1 MW), short wavelength (2 mm) gyrotron electromagnetic (GEM) wiggler for use in a compact free electron laser (FEL). The gyrotron consisted of an electron gun and resonator section followed by a special high Q cavity for storing the power created in the gyrotron resonator. The electromagnetic field stored in the high Q cavity would then be appropriate for use as a wiggler field in an infrared or visible FEL with a moderate energy (4 to 10 MeV) electron beam. The gyrotron experiment tested the practical limits due to ohmic loss, mode conversion, etc. on the strength of such a stored field. It also tested the effect of strong feedback from the high Q cavity back onto the gyrotron resonator. The proposed research utilized the technology of high power, high frequency gyrotrons developed at M.I.T. as part of the Department of Energy program on development of sources for plasma heating

  7. High harmonic terahertz confocal gyrotron with nonuniform electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Wenjie; Guan, Xiaotong; Yan, Yang [THz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-01-15

    The harmonic confocal gyrotron with nonuniform electron beam is proposed in this paper in order to develop compact and high power terahertz radiation source. A 0.56 THz third harmonic confocal gyrotron with a dual arc section nonuniform electron beam has been designed and investigated. The studies show that confocal cavity has extremely low mode density, and has great advantage to operate at high harmonic. Nonuniform electron beam is an approach to improve output power and interaction efficiency of confocal gyrotron. A dual arc beam magnetron injection gun for designed confocal gyrotron has been developed and presented in this paper.

  8. Theory and Modeling of High-Power Gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Nusinovich, Gregory Semeon [Univ. of Maryland, College Park, MD (United States)

    2016-04-29

    This report summarized results of the work performed at the Institute for Research in Electronics and Applied Physics of the University of Maryland (College Park, MD) in the framework of the DOE Grant “Theory and Modeling of High-Power Gyrotrons”. The report covers the work performed in 2011-2014. The research work was performed in three directions: - possibilities of stable gyrotron operation in very high-order modes offering the output power exceeding 1 MW level in long-pulse/continuous-wave regimes, - effect of small imperfections in gyrotron fabrication and alignment on the gyrotron efficiency and operation, - some issues in physics of beam-wave interaction in gyrotrons.

  9. 28 GHz Gyrotron ECRH Upgrade for LDX

    Science.gov (United States)

    Michael, P. C.; Woskov, P. P.; Ellsworth, J. L.; Kesner, J.; Garnier, D. T.; Mauel, M. E.; Ellis, R. F.

    2009-11-01

    A 10 kW, CW, 28 GHz gyrotron is being implemented on LDX to increase the plasma density and to more fully explore the potential of high beta plasma stability in a dipole magnetic configuration. Higher density increases the heating of ions by thermal equilibration and allows for improved wave propagation in planned ICRF experiments. This represents over a 50% increase in the 17 kW ECRH from sources at 2.45, 6.4, and 10.5 GHz. The higher frequency will also make possible access to plasma densities of up to 10^13 cm-3. The 1 Tesla resonances are located above and below the floating coil near the dipole axial region. The gyrotron beam will be transmitted in TE01 mode in 32.5 mm diameter guide using one 90 bend and a short Tesla resonance region. A layout of the planned system will be presented.

  10. Improved Collectors for High Power Gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Ives, R. Lawrence; Singh, Amarjit; Read, Michael; Borchard, Phillipp; Neilson, Jeff

    2009-05-20

    High power gyrotrons are used for electron cyclotron heating, current drive and parasitic mode suppression in tokamaks for fusion energy research. These devices are crucial for successful operation of many research programs around the world, including the ITER program currently being constructed in France. Recent gyrotron failures resulted from cyclic fatigue of the copper material used to fabricated the collectors. The techniques used to collect the spent beam power is common in many gyrotrons produced around the world. There is serious concern that these tubes may also be at risk from cyclic fatigue. This program addresses the cause of the collector failure. The Phase I program successfully demonstrated feasibility of a mode of operation that eliminates the cyclic operation that caused the failure. It also demonstrated that new material can provide increased lifetime under cyclic operation that could increase the lifetime by more than on order of magnitude. The Phase II program will complete that research and develop a collector that eliminates the fatigue failures. Such a design would find application around the world.

  11. Design of Single disc RF window for High Power Gyrotron

    International Nuclear Information System (INIS)

    In this paper investigates the design of water edge cooled single-disc CVD-diamond window for 120 GHz, 1MW gyrotron. The design of RF window for 120 GHz, 1MW gyrotron has been carried out using the CST microwave studio. In 120 GHz gyrotron single disc of diameter 90 mm and thickness 2.0 mm CVD diamond window has been used in the simulation. The return loss (S11) and transmission loss (S21) of the 120 GHz gyrotron window have been found - 40.0 dB and -0.02 dB respectively. Thermal analysis of single disc rf window has also been carried out using ANSYS software for high power 120 GHz gyrotron. The temperature range on the disc surface has been found to be 100 °C - 300 ° C.

  12. A high-order particle-in-cell method for low density plasma flow and the simulation of gyrotron resonator devices

    Energy Technology Data Exchange (ETDEWEB)

    Stock, Andreas

    2013-04-26

    of its huge computational demand and the thereby resulting long calculation time. Using the presented high-order discontinuous Galerkin Particle-in-Cell scheme on high-performance-computers, this thesis demonstrates for the first time that full-wave and transient research- and design-simulations of gyrotron resonators with high mode-indices can be efficiently performed. For benchmark issues the developed discontinuous Galerkin Particle-in-Cell scheme is verified with a 30 GHz resonant cavity and the results are compared to the SELFT code, which is a state-of-the-art design code for resonators. The discontinuous Galerkin Particle-in-Cell scheme is used to simulate the resonator of the 1 MW, 140 GHz, TE(28,8)-mode gyrotron, used for plasma heating of the Wendelstein 7-X fusion-reactor. Due to the huge number of degrees of freedom and particles, this type of simulation can only be performed on high-performance-computers with enough memory and computational power. Hence, the discontinuous Galerkin Particle-in-Cell code is improved by a new parallelization approach for the high-order shape-function deposition method on unstructured grids, allowing for a high-order coupling between the particles and the electromagnetic field. To further improve the discontinuous Galerkin Particle-in-Cell code, a multi-rate time-stepping method, based on an Adams-Bashforth approach, for the hyperbolic divergence cleaning is developed and verified. This new approach considers the different time scales occurring in the hyperbolic divergence cleaning allowing for a more efficient time-stepping-algorithm then standard time-stepping-schemes. A rule for the construction of arbitrary-order multi-rate time-stepping methods has been derived. The presented simulations provide new physical insights to the complex particle-field-interaction appearing in gyrotrons. The discontinuous Galerkin Particle-in-Cell scheme can be used to analyse transient phenomena, such as beam-miss-alignment, mode competition

  13. 110 GHz, 1 MW Gyrotron Design Upgrades

    Science.gov (United States)

    Cauffman, Steve; Felch, Kevin; Borchard, Philipp; Cahalan, Pat; Chu, Sam; Dubrule, Craig

    1999-11-01

    Communications and Power Industries has incorporated a number of design changes into its most recent series of 110 GHz 1 MW gyrotrons, for use in ECH and ECCD experiments on the DIII-D tokamak. Two development gyrotrons previously installed at DIII-D used a modulating-anode electron gun design and output windows consisting of double-disk face-cooled sapphire on one system and an edge-cooled CVD diamond disk on the other. Three new systems presently in fabrication and test employ (a) a single-anode electron gun to avoid excitation of spurious modes during turn-on and turn-off and to simplify power supply requirements, (b) a modified TE_22,6 cavity to reduce competition from neighboring modes, (c) a two inch aperture edge-cooled CVD diamond window to allow transmission of a 1 MW Gaussian output beam, (d) a superconducting magnet system with a cryo-cooler to reduce liquid helium consumption, and (e) a number of internal and external plumbing simplifications to make cooling system connections more straightforward. Initial test results, if available, will be presented.

  14. 28 GHz Gyrotron ECRH on LDX

    Science.gov (United States)

    Woskov, P. P.; Kesner, J.; Michael, P. C.; Garnier, D. T.; Mauel, M. E.

    2010-12-01

    A 10 kW, CW, 28 GHz gyrotron has been implemented on LDX to increase the plasma density and to more fully explore the potential of high beta plasma stability in a dipole magnetic configuration. This added power represents about a 60% increase in ECRH to a new total of 26.9 kW with sources at 2.45, 6.4, and 10.5 GHz. The 1 Tesla resonances in LDX form small rings encompassing the entire plasma cross-section above and below the floating coil (F-coil) near the dipole axial region. A 32.5 mm diameter TE01 waveguide with a partial Vlasov step cut launches a diverging beam from above the F-coil that depends on internal wall reflections for plasma coupling. Initial gyrotron only plasmas exhibit steep natural profiles with fewer hot electrons than with the other sources. The background scattered radiation suggests that only about half the power is being absorbed with the present launcher.

  15. High power millimeter and submillimeter wave lasers and gyrotrons

    Science.gov (United States)

    Temkin, R. J.; Cohn, D. R.; Danly, B. G.; Kreischer, K. E.; Woskoboinikow, P.

    1985-10-01

    High power sources of coherent radiation in the millimeter and submillimeter wavelength range are useful in a number of applications, including plasma heating, plasma diagnostics, radar and communications. Two of the most important sources in this wavelength range are the optically pumped laser and the gyrotron. Major recent advances in both laser and gyrotron research are described. Possible techniques for improving the efficiency and operating characteristics of these devices are also reviewed.

  16. Technical developments at the KIT gyrotron test facility

    International Nuclear Information System (INIS)

    Parasitic beam tunnel oscillations have been discovered on some of the series production gyrotrons for W7-X and also on the coaxial pre-prototype gyrotron for ITER. Solutions to remedy these problems have resulted in a modified beam tunnel design, technologically close to the existing beam tunnel. The new design has successfully been tested on both the coaxial and also the f-step-tunable gyrotrons and has subsequently been implemented on one of the W7-X series-production-tubes presently undergoing factory acceptance tests in Karlsruhe. The ECRH test loads at KIT are operated under normal atmospheric conditions. Several loads have eventually failed in 1 MW long pulse experiments and KIT has therefore started to design its own loads. The first KIT-load is based on a fixed conical mirror and an aluminum cylinder coated with a lossy material for increased absorption. The new load has so far successfully been used during the acceptance tests of two 1-MW CW gyrotrons. Nevertheless a new load based on pure (uncoated) stainless steel absorbers is being developed as a backup solution for the ongoing high priority gyrotron testing. A superconducting magnet capable of rapid field changes between 4.15 and 5.67 T for frequency step-tunable gyrotrons has been procured, has demonstrated a (static) field of 7.2 T and its capability of rapid field-changes.

  17. A simple quantum-electronic approach to the Gyrotron and its application to the solid-state gyrotron

    Science.gov (United States)

    Ho, P.-T.; Granatstein, V. L.

    1986-01-01

    A simple, unifying theory of the gyrotron is presented. It is of the Lamb type. Within its framework, important results from different approaches can be easily obtained. As an application, gyrotron action in InSb is reexamined, and coherent emission at 10 to the 12th Hz appears possible with an output power of about 0.5 mW/sq mm of the device.

  18. Gyrotrons for magnetic fusion applications at 110 GHz and 170 GHz

    Directory of Open Access Journals (Sweden)

    Cahalan P.

    2012-09-01

    Full Text Available Two megawatt-class gyrotrons at frequencies of 110 GHz and 170 GHz have recently been fabricated at CPI. The 110 GHz gyrotron is designed to produce 1.2 MW of output power for 10-second pulses, and will be used for electron cyclotron heating and current drive on the DIII-D tokamak at General Atomics. This gyrotron has completed factory testing and has been delivered to General Atomics for installation and additional testing. The 170 GHz gyrotron, though specified as a 500 kW CW system, has been designed with the goal of generating up to 1 MW CW. Oak Ridge National Laboratory will use this gyrotron in ITER ECH transmission line testing. This gyrotron has been fabricated and is awaiting factory testing, Design features of each gyrotron are described, and test data for the 110 GHz gyrotron are presented.

  19. Designing A Mode Converter For Use With A Gyrotron

    Science.gov (United States)

    Hoppe, Daniel J.

    1995-01-01

    Report describes process of designing corrugated, circular-cross-section length of waveguide converting input electromagnetic radiation at frequency of 34.5 GHz in TM(11) mode to output radiation in HE(11) mode. TM(11)-mode input radiation supplied by gyrotron generating continuous-wave power of 200 kW at 34.5 GHz in TE(01) mode followed by TE(01)-to-TM(11) mode converter. Together, gyrotron and mode converters constitute prototype high-power transmitter for long-distance free-space communication.

  20. Phase locking and bandwidth in a gyrotron oscillator

    Science.gov (United States)

    Latham, P. E.; Granatstein, V. L.; Carmel, Y.

    1993-06-01

    For imaging radar and for satellite and space communication (e.g. NASA's deep space network), it is important that the bandwidth be as large as possible. Here we derive a formalism for computing the phase locking bandwidth that can be achieved in a gyrotron oscillator while varying the beam voltage. As an example, a second harmonic TE02/03 gyrotron is considered. For this device, the effective bandwidth can be increased by a factor of about 3 compared with the fixed voltage case by allowing the beam voltage to change together with the input locking signal.

  1. Oscillating virtual cathode, large-orbit gyrotron and driver

    Energy Technology Data Exchange (ETDEWEB)

    VanHaaften, F.W.; Hoeberling, R.F.; Fazio, M.V.

    1986-01-01

    Studies using an oscillating virtual cathode (vircator) and a large-orbit gyrotron to generate microwave levels of several hundred megawatts are being conducted at the Los Alamos National Laboratory (LANL). A pulse level of approx.1 MV, with length approaching 1 ..mu..s at a repetition rate of a few hertz, is anticipated for extension of these studies from the present single-shot mode with 100-ns pulse width. The increased pulse width is needed to test longer pulse length microwave sources. Pulse forming network (PFN), transformer-coupled drivers have been studied and are part of the subject of this paper. The large-orbit gyrotron is discussed here.

  2. Suppression of parasitic space-charge oscillations in a gyrotron

    Science.gov (United States)

    Louksha, O. I.; Piosczyk, B.; Sominski, G. G.; Thumm, M.; Samsonov, D. B.

    2006-10-01

    We study the influence of nonuniform electric and magnetic fields in the helical-beam compression region on the low-frequency parasitic space-charge oscillations for a moderate-power (˜ 100 kW) 4-mm gyrotron. Suppression of the oscillations is achieved by optimization of both the cathode-unit geometry in the magnetron-injector gun and the magnetic-field distribution in the region near the cavity input. The obtained data are evidence of possible effective operation of the gyrotron at elevated pitch-factor values α > 1.5 even for emitters with no highest emission uniformity (δje ≈ 30%).

  3. Active heater control and regulation for the Varian VGT-8011 gyrotron

    International Nuclear Information System (INIS)

    The Varian VGT-8011 gyrotron is currently being used in the new 110 GHz 2 MW ECH system installed on D3-D. This new ECH system augments the 60 GHz system which uses Varian VA-8060 gyrotrons. The new 110 GHz system will be used for ECH experiments on D3-D with a pulse width capability of 10 sec. In order to maintain a constant RF outpower level during long pulse operation, active filament-heater control and regulation is required to maintain a constant cathode current. On past D3-D experiments involving the use of Varian VA-8060 gyrotrons for ECH power, significant gyrotron heater-emission depletion was experienced for pulse widths > 300 msec. This decline in heater-emission directly results in gyrotron-cathode current droop. Since RF power from gyrotrons decreases as cathode current decreases, it is necessary to maintain a constant cathode current level during gyrotron pulses for efficient gyrotron operation. Therefore, it was determined that a filament-heater control system should be developed for the Varian VGT-8011 gyrotron which will include cathode-current feed-back. This paper discusses the mechanisms used to regulate gyrotron filament-heater voltage by using cathode-current feed-back. 1 fig

  4. Research on advanced high power gyrotrons at FZK

    International Nuclear Information System (INIS)

    The experimental 170 GHz coaxial cavity gyrotron for ITER has been assembled and installed in the SC magnet. The operation started in May 2004 with performing the alignment and conditioning of the tube. The main goal of the experiments is to verify the design of components for a 2 MW, CW industrial prototype

  5. Status of the new multi-frequency ECRH system for ASDEX Upgrade

    DEFF Research Database (Denmark)

    Wagner, D.; Grünwald, G.; Leuterer, F.;

    2008-01-01

    Currently, a new multi-frequency ECRH system is under construction at the ASDEX Upgrade tokamak experiment. This system employs, for the first time in a fusion device, multi-frequency gyrotrons, step-tunable in the range 105-140 GHz. The first two gyrotrons, working at 105 and 140 GHz, were insta...

  6. Development of 100 GHz band high power gyrotron for fusion experimental reactor

    International Nuclear Information System (INIS)

    In JAERI, 1MW gyrotrons of 170GHz and 110GHz are under development for ITER (International Thermonuclear Experimental Reactor) and JT-60U, respectively. Both gyrotrons have a depressed collector for an efficiency improvement and a low loss synthetic diamond window that enables Gaussian beam output over 1MW. Three 110GHz gyrotrons are used on an electron cyclotron heating and current drive(ECH/ECCD) system on JT-60U, in which the output power of ∼0.8MW/3sec was generated from each gyrotron. As for 170GHz, output power of 1.2MW with electron beam of 85kV/49A was obtained on a short pulse gyrotron. The efficiency of ∼57% was attained at 1.1MW with the depressed collector. Based on these results, the 1MW 170GHz gyrotron for long pulse operation was fabricated. (author)

  7. A novel vacuum window for megawatt gyrotrons

    Science.gov (United States)

    Haldeman, George Stephenson

    2001-08-01

    This thesis describes a new microwave output window for megawatt power level, 110 GHz gyrotrons. The window uses two spherically polished sapphire elements separated by a nearly uniform gap of about 1 mm. Pressurized, microwave transparent coolant flows through this gap and across the transmitting aperture, removing absorbed energy at the element face. The design differs from previous face- cooled windows because the sapphire elements have a modestly curved dome, rather than flat shape. This curved shape increases the element's capability to withstand coolant pressures without significantly increasing stresses from differential heating. Consequently, window power can be increased either through enhanced, high pressure cooling or by using thinner elements with reduced microwave absorption. A model was developed to predict window power capability as a function of design geometry. This model predicted an increase from 0.5 to 2.1 MW when flat elements were changed to curved. Both designs used full size, 100mm clear apertures, but the curved elements with 214 mm curvature radii were 1.3 rather than 1.75 mm thick. The model was also used to design a half size prototype experiment. This 50 mm clear aperture system used 60 mm OD x 0.47 mm thick x 107 mm surface radius elements. An initial piece was fabricated and statically tested to a pressure of 1.1 MPa well above the 0.5 MPa analytically predicted to be required for megawatt operation. The complete window structure was then fabricated, including instrumentation to simulate microwave heating and to measure induced temperatures and strains. Test results demonstrated an equivalent continuous Gaussian beam power capability of 700 kW using a coolant flow of 1.1 lps. Scaling from this measurement, fall size boiling limited power is expected to be 1.1 MW for a Gaussian microwave intensity profile, or 2.3 MW for a shaped profile typical of previous flat, face-cooled designs. (Copies available exclusively from MIT Libraries, Rm

  8. Recent Tests on 117.5 GHz and 170 GHz Gyrotrons

    Directory of Open Access Journals (Sweden)

    Felch K.

    2015-01-01

    Full Text Available Two megawatt-class gyrotrons at frequencies of 117.5 GHz and 170 GHz have recently been fabricated and tested at CPI. The 117.5 GHz gyrotron was designed to produce up to 1.8 MW for 10-second pulses, and will be used for electron cyclotron heating and current drive on the DIII-D tokamak at General Atomics. The 170 GHz gyrotron is specified as a 500 kW CW system, but has been designed with the goal of generating up to 1 MW CW. Oak Ridge National Laboratory will use the gyrotron in ITER ECH transmission line testing.

  9. Solid-state gyrotron body power supply, test results

    Energy Technology Data Exchange (ETDEWEB)

    Santinelli, M. [Association Euratom-ENEA, ENEA CR Frascati, 00044 Frascati (Italy)], E-mail: santinelli@frascati.enea.it; Claesen, R.; Coletti, A. [Association Euratom-ENEA, ENEA CR Frascati, 00044 Frascati (Italy); Bonicelli, T.; Mondino, P.L. [EFDA, EFDA CSU Garching, D-85748 Garching (Germany); Pretelli, M.; Rinaldi, L.; Sita, L.; Taddia, G. [OCEM SpA, Via 2 Agosto 1980 no. 11, 40016 San Giorgio di Piano (Italy)

    2007-10-15

    A 170 GHz, 2 MW, steady-state gyrotron is being developed in collaboration between European research associations and industries to be used for the electron cyclotron resonance heating (ECRH) system of ITER, the gyrotron is presently in the prototype state. EFDA entrusted ENEA with the design of a new power supply for the gyrotron's body; in which, the traditional power vacuum tubes are replaced with solid-state components (IGBT); furthermore ENEA had the task of developing the new body power supply (BPS), following the initial conceptual design. The BPS is formed by 50 identical bidirectional (in current) modules, connected in series; the BPS's control system regulates the output voltage by changing the modulation index. OCEM Spa, under ENEA's supervision, has manufactured the BPS. Tests, done at the start of this year, showed the substantial agreement between the initial technical specifications and the values achieved. Particularly the ramp-up/down-emergency time (50-10 {mu}s), the accuracy ({+-}0.5%), the sine wave modulation (45-20 kV at 5 kHz) and the maximum phase shift (<10 deg.) have been tested. In the article, the new stair-way modulation (SWM) scheme will be sketched and the test results will be described in detail.

  10. Investigations and advanced concepts on gyrotron interaction modeling and simulations

    Science.gov (United States)

    Avramidis, K. A.

    2015-12-01

    In gyrotron theory, the interaction between the electron beam and the high frequency electromagnetic field is commonly modeled using the slow variables approach. The slow variables are quantities that vary slowly in time in comparison to the electron cyclotron frequency. They represent the electron momentum and the high frequency field of the resonant TE modes in the gyrotron cavity. For their definition, some reference frequencies need to be introduced. These include the so-called averaging frequency, used to define the slow variable corresponding to the electron momentum, and the carrier frequencies, used to define the slow variables corresponding to the field envelopes of the modes. From the mathematical point of view, the choice of the reference frequencies is, to some extent, arbitrary. However, from the numerical point of view, there are arguments that point toward specific choices, in the sense that these choices are advantageous in terms of simulation speed and accuracy. In this paper, the typical monochromatic gyrotron operation is considered, and the numerical integration of the interaction equations is performed by the trajectory approach, since it is the fastest, and therefore it is the one that is most commonly used. The influence of the choice of the reference frequencies on the interaction simulations is studied using theoretical arguments, as well as numerical simulations. From these investigations, appropriate choices for the values of the reference frequencies are identified. In addition, novel, advanced concepts for the definitions of these frequencies are addressed, and their benefits are demonstrated numerically.

  11. Infrared monitoring of 110 GHz gyrotron windows at DIII-D

    International Nuclear Information System (INIS)

    The combination of low millimeter wave losses and excellent thermal conductivity with good mechanical properties make artificial chemical vapor deposition (CVD) diamonds a compelling choice for 1 MW 110 GHz gyrotron windows. Five gyrotrons are currently operating at the DIII-D tokamak. Three Gycom gyrotrons have boron nitride (BN) ceramic windows. Due to temperature increases of the windows up to about 930 deg. C, the pulse duration of these tubes is limited to 2 s for output power near 800 kW. Two Communications and Power Industries (CPI) gyrotrons with diamond windows are also installed and operating. The diamond disks of these windows and the construction of their water-cooling assemblies are different. This paper reviews the infrared (IR) measurements of both types of gyrotron windows, with emphasis on the two diamond designs. (authors)

  12. Infrared Monitoring of 110 GHz Gyrotron Windows at Diii-D

    Science.gov (United States)

    Gorelov, Y.; Lohr, J.; Callis, R. W.; Ponce, D.

    2003-02-01

    The combination of low millimeter wave losses and excellent thermal conductivity with good mechanical properties make artificial chemical vapor deposition (CVD) diamonds a compelling choice for 1 MW 110 GHz gyrotron windows. Five gyrotrons are currently operating at the DIII-D tokamak. Three Gycom gyrotrons have boron nitride (BN) ceramic windows. Due to temperature increases of the windows up to about 930°C, the pulse duration of these tubes is limited to 2 s for output power near 800 kW. Two Communications and Power Industries (CPI) gyrotrons with diamond windows are also installed and operating. The diamond disks of these windows and the construction of their water-cooling assemblies are different. This paper reviews the infrared (IR) measurements of both types of gyrotron windows, with emphasis on the two diamond designs.

  13. Possibilities for Continuous Frequency Tuning in Terahertz Gyrotrons with Nontunable Electrodynamic Systems

    Science.gov (United States)

    Bratman, V. L.; Savilov, A. V.; Chang, T. H.

    2016-02-01

    Large ohmic losses in the cavities of terahertz gyrotrons may lead to the overlapping of the axial mode spectra. In a number of gyrotron experiments, this effect has been used to provide a fairly broadband frequency tuning by changing appropriately the operating magnetic field and/or accelerating voltage of the gyrotron. Similar to the systems with nonfixed axial structure of the RF electromagnetic field and low diffraction quality, which are due to weak reflections of the operating wave from the collector end of the electrodynamic system, this changing leads to a monotonic change in the axial index of the operating wave and transition from the gyrotron regime to the gyro-BWO regime. According to a theoretical comparison of these two methods performed on the basis of generalization of self-consistent gyrotron equations with allowance for variations in the axial electron momenta, low-reflection systems can provide a higher efficiency and monotonicity of the frequency tuning.

  14. Research on a 170 GHz, 2 MW coaxial cavity gyrotron with inner-outer corrugation

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Shenyong, E-mail: houshenyong@sohu.com [Yangtze Normal University, Chongqing, 408001 (China); Yu, Sheng; Li, Hongfu [University of Electronics Science and Technology of China, Chengdu 610054 (China)

    2015-03-15

    In this paper, a coaxial cavity gyrotron with inner-outer corrugation is researched. The electron kineto-equations and the first order transmission line equations of the gyrotron are derived from Lorentz force equation and the transmission line theory, respectively. And then, a 2 MW, 170 GHz coaxial cavity gyrotron with inner-outer corrugation is designed. By means of numerical calculation, the beam-wave interaction of the coaxial cavity gyrotron with inner-outer corrugation is investigated. Results show that the efficient and the outpower of the gyrotron are 42.3% and 2.38 MW, respectively.

  15. High power 303 GHz gyrotron for CTS in LHD

    Science.gov (United States)

    Yamaguchi, Y.; Kasa, J.; Saito, T.; Tatematsu, Y.; Kotera, M.; Kubo, S.; Shimozuma, T.; Tanaka, K.; Nishiura, M.

    2015-10-01

    A high-power pulsed gyrotron is under development for 300 GHz-band collective Thomson scattering (CTS) diagnostics in the Large Helical Device (LHD). High-density plasmas in the LHD require a probe wave with power exceeding 100 kW in the sub-terahertz region to obtain sufficient signal intensity and large scattering angles. At the same time, the frequency bandwidth should be less than several tens of megahertz to protect the CTS receiver using a notch filter against stray radiations. Moreover, duty cycles of ~ 10% are desired for the time domain analysis of the CTS spectrum. At present, a 77 GHz gyrotron for electron cyclotron heating is used as a CTS wave source in the LHD. However, the use of such a low-frequency wave suffers from refraction, cutoff and absorption at the electron cyclotron resonance layer. Additionally, the signal detection is severely affected by background noise from electron cyclotron emission. To resolve those problems, high-power gyrotrons in the 300 GHz range have been developed. In this frequency range, avoiding mode competition is critical to realizing high-power and stable oscillation. A moderately over-moded cavity was investigated to isolate a desired mode from neighbouring modes. After successful tests with a prototype tube, the practical one was constructed with a cavity for TE22,2 operation mode, a triode electron gun forming intense laminar electron beams, and an internal mode convertor. We have experimentally confirmed single mode oscillation of the TE22,2 mode at the frequency of 303.3 GHz. The spectrum peak is sufficiently narrow. The output power of 290 kW has been obtained at the moment.

  16. The Development of 460 GHz gyrotrons for 700 MHz DNP-NMR spectroscopy

    Science.gov (United States)

    Idehara, T.; Tatematsu, Y.; Yamaguchi, Y.; Khutoryan, E. M.; Kuleshov, A. N.; Ueda, K.; Matsuki, Y.; Fujiwara, T.

    2015-07-01

    Two demountable gyrotrons with internal mode converters were developded as sub-THz radiation sources for 700 MHz DNP (Dynamic Nuclear Polarization) enhanced NMR spectroscopy. Experimental study on the DNP-NMR spectroscopy will be carried out in Osaka University, Institute for Protein Research, as a collaboration with FIR UF. Both gyrotrons operate near 460 GHz and the output CW power measured at the end of transmission system made by circular waveguides is typically 20 to 30 watts. One of them named Gyrotron FU CW GVI (we are using "Gyrotron FU CW GO-1" as an official name in Osaka University) is designed to have a special function of high speed frequency modulation δ f within 100 MHz band. This will expand excitable band width of ESR and increase the number of electron spins contributing to DNP. The other gyrotron, Gyrotron FU CW GVIA ("Gyrotron FU CW GO-II") has a function of frequency tunability Δ f in the range of wider than 1.5 GHz, which is achieved in steady state by changing magnetic field intensity. This function should be used for adjusting the output frequency at the optimal value to achieve the highest enhancement factor of DNP.

  17. Influence of construction concepts on training behavior of gyrotron magnets

    International Nuclear Information System (INIS)

    A series of 60 NbTi gyrotron magnets intended mainly for high frequency plasma heating complexes at Tokamak T-10 and Tokamak T-15, and prototypes and later improved versions for the same applications within ITER project, were developed and tested. A variety of constructional and technological concepts was applied. As a result of empirical experience in parallel with the application of established theoretical models to the magnet development, a remarkable improvement in winding mechanical stability was reached. The differences in magnet winding construction are related to operational as well as training and quench behaviour. (Author)

  18. A 2 MW, 170 GHz coaxial cavity gyrotron - experimental verification of the design of main components

    International Nuclear Information System (INIS)

    A 2 MW, CW, 170 GHz coaxial cavity gyrotron is under development in cooperation between European Research Institutions (FZK Karlsruhe, CRPP Lausanne, HUT Helsinki) and the European tube industry (TED, Velizy, France). The design of critical components has recently been examined experimentally at FZK Karlsruhe with a short pulse (∼ few ms) coaxial cavity gyrotron. This gyrotron uses the same cavity and the same quasioptical (q.o.) RF-output system as designed for the industrial prototype and a very similar electron gun

  19. HIGH POWER LONG PULSE PERFORMANCE OF THE DIII-D GYROTRON INSTALLATION

    Energy Technology Data Exchange (ETDEWEB)

    J. LOHR; Y.A. GORELOV; R.W. CALLIS; H.J. GRUNLOH; J.J. PEAVY; R.I. PINSKER; D. PONCE; R. PRATER; R.A. ELLIS,III

    2002-05-01

    At DIII-D, five 110 GHz gyrotrons are operating routinely for 2.0 s pulses at generated power levels {ge}750 kW per gyrotron. A sixth gyrotron is being installed, which should bring the generated power level to >4 MW and the injected power to about 3.0 MW. The output power now can be modulated by the plasma control system to fix T{sub e} at a desired value. The system is being used as a tool for control of current diffusion, for current profile control and other experiments leading to advanced tokamak operation.

  20. Application of Fusion Gyrotrons to Enhanced Geothermal Systems (EGS)

    Science.gov (United States)

    Woskov, P.; Einstein, H.; Oglesby, K.

    2013-10-01

    The potential size of geothermal energy resources is second only to fusion energy. Advances are needed in drilling technology and heat reservoir formation to realize this potential. Millimeter-wave (MMW) gyrotrons and related technologies developed for fusion energy research could contribute to enabling EGS. Directed MMW energy can be used to advance rock penetration capabilities, borehole casing, and fracking. MMWs are ideally suited because they can penetrate through small particulate extraction plumes, can be efficiently guided long distances in borehole dimensions, and continuous megawatt sources are commercially available. Laboratory experiments with a 10 kW, 28 GHz CPI gyrotron have shown that granite rock can be fractured and melted with power intensities of about 1 kW/cm2 and minute exposure times. Observed melted rock MMW emissivity and estimated thermodynamics suggest that penetrating hot, hard crystalline rock formations may be economic with fusion research developed MMW sources. Supported by USDOE, Office of Energy Efficiency and Renewable Energy and Impact Technologies, LLC.

  1. A Two Frequency 1.5 MW Gyrotron Experiment

    Science.gov (United States)

    Tax, David; Guss, William; Shapiro, Michael; Temkin, Richard; Rock, Ben; Vernon, Ronald; Neilson, Jeffrey

    2012-10-01

    Megawatt gyrotrons are an important microwave source for electron cyclotron heating and current drive (ECH/ECCD) in fusion plasmas due to their ability to produce megawatts of power at millimeter wave frequencies. The MIT gyrotron operates nominally at 96 kV and 40 A with 3 μs pulses and has previously demonstrated 1.5 MW of output power with > 50 % efficiency at 110 GHz with a depressed collector. A new cavity has been designed for 1.5 MW operation at two distinct frequencies: 110 GHz in the TE22,6 mode and 124.5 GHz in the TE24,7 mode. A new internal mode converter (IMC) consisting of a dimpled wall launcher and four smooth curved mirrors has also been designed and was optimized for both modes. Simulations of the IMC indicate that > 98 % Gaussian beam content could be achieved for each mode. Cold test results for the components will be presented as well as the current status of the hot test experiment.

  2. Numerical study on a 0.4 THz second harmonic gyrotron with high power

    International Nuclear Information System (INIS)

    Terahertz and sub-terahertz science and technology are promising topics today. However, it is difficult to obtain high power source of terahertz wave. In this paper, the mode competition and beam-wave interaction in a gradually tapered cavity are studied to achieve high efficiency of a 0.4THz second harmonic gyrotron in practice. In order to attain high power and stable radiation, the TE32,5 mode is selected as the operating mode of the desired gyrotron to realize single mode oscillation. The issues of studying on the high-order mode gyrotrons are solved effectively by transforming the generalized telegraphist's equations. The efficiency and output power of the gyrotron under different conditions have been calculated by the code, which is based on the transformed equations. Consequently, the results show that single mode second harmonic radiation with power of over 150 kW at frequency of 0.4 THz could be achieved

  3. Cold test of cylindrical open resonator for 42 GHz, 200 kW gyrotron

    Indian Academy of Sciences (India)

    Vivek Yadav; Sudeep Sharan; Hasina Khatun; Nitin Kumar; M K Alaria; B Jha; S C Deorani; A K Sinha; P K Jain

    2013-12-01

    This paper presents experimental results for cold testing of a gyrotron open resonator. Experiments were carried out to measure resonant frequency and their particular quality factor for TE mode at the frequency 42 GHz. The perturbation technique was used to determine the axial, radial and azimuthal electric field profile for identification of TE031 mode at operating frequency 42 GHz. The good agreement between experimental results and theoretical studies was found. The results verify the design and fabrication of the specific gyrotron cavity.

  4. Design of an electronically tunable millimeter wave Gyrotron Backward Wave Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M.

    1987-01-01

    A non-linear self-consistent computer simulation code is used to analyze the saturated output of the Gyrotron Backward Wave Oscillator (Gyro BWO) which can be used as a tunable driver for a 250 GHz FEL amplifier. Simulations show that the Gyrotron BWO using a Pierce/Wiggler gun configuration can produce at least 10 kW of microwave power over the range 249 GHz to 265 GHz by varying beam voltage alone.

  5. Gyrotron physics from linear to chaotic regimes: experiment and numerical modeling

    OpenAIRE

    Braunmüller, Falk Hans

    2016-01-01

    Gyrotrons belong to the family of high-power coherent radiation sources known as Electron Cyclotron Masers (ECMs) and are based on the physical mechanism of the ECM-instability, converting electron rotational kinetic energy into coherent electromagnetic radiation. The worldwide gyrotron R&D is mainly driven by the application in heating a magnetically confined fusion plasma, which requires coherent radiation sources with MW power-level in the sub-THz frequency range. In the last two decades,...

  6. 1.5 MW, 110 GHz Gyrotron with a Depressed Collector

    Science.gov (United States)

    Choi, Eunmi; Anderson, James; Shapiro, Michael; Jagadishwar, Sirigiri; Temkin, Richard

    2004-11-01

    A 1.5 MW, 110 GHz gyrotron is under development for electron cyclotron resonance plasma heating at DIII-D. Research conducted at MIT in short pulse operation is aimed at providing data on the operation of the gyrotron at very high efficiency. The 1.5 MW gyrotron design is based on previous successful results from the 1 MW gyrotrons built by Communication and Power Industries (CPI). A TE_22,6 mode cavity is utilized with an electron beam voltage of 96 kV and a beam current of 40 A. Recently we have successfully run the gyrotron in the axial configuration, and the experimental peak power was 1.44 MW at 37 % efficiency, when operating in the TE_22,6 mode. We have rebuilt this experiment in a configuration which has an internal mode converter and depressed collector, which should enhance the efficiency (> 50 %). The internal mode converter of the TE_22,6 mode to a Gaussian beam consists of an irregular waveguide launcher and four quasi-optical mirrors. A new cavity that provides greatly reduced Ohmic heating on the wall has been designed to enhance the gyrotron efficiency. This cavity will be tested in the next stage of the experiment.

  7. Optimization of operation of a three-electrode gyrotron with the use of a flow-type calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Kharchev, Nikolay K.; Batanov, German M.; Kolik, Leonid V.; Malakhov, Dmitrii V.; Petrov, Aleksandr Ye.; Sarksyan, Karen A.; Skvortsova, Nina N.; Stepakhin, Vladimir D. [Prokhorov General Physics Institute, Vavilova ul. 38, Moscow 119991 (Russian Federation); Belousov, Vladimir I. [Institute of Applied Physics, Ul' yanova ul. 46, Nizhnii Novgorod 603950 (Russian Federation); Malygin, Sergei A.; Tai, Yevgenii M. [GYCOM Company, Ul' yanova ul. 46, Nizhnii Novgorod 603155 (Russian Federation)

    2013-01-15

    Results are presented for measurements of microwave power of the Borets-75/0.8 gyrotron with recovery of residual electron energy, which were performed by a flow-type calorimeter. This gyrotron is a part of the ECR plasma heating complex put into operation in 2010 at the L-2M stellarator. The new calorimeter is capable of measuring microwave power up to 0.5 MW. Monitoring of the microwave power makes it possible to control the parameters of the gyrotron power supply unit (its voltage and current) and the magnetic field of the cryomagnet in order to optimize the gyrotron operation and arrive at maximum efficiency.

  8. Gyrotron development at the Instituto de Pesquisas Espaciais

    International Nuclear Information System (INIS)

    The conceptual design of a 35GHz gyrotron operating in the TE021 mode, intended for plasma heating experiments, is presented. The electrooptical system is synthesized from the electron beam parameters in the cavity region and the electrodynamical system includes a conventional resonator consisting of truncated cones. The starting and operating characteristics are calculated by integrating the exact equation of electron motion under the action of an RF fiel with fixed spatial distribution. For the moment, the experimental activities, in addition to providing all the infrastructure for the laboratory, are concentrated on the construction of a system of magnetic coils, able to generated a 15kG magnetic induction with a fluctuation of 0.1% over an extension of 13cm, on the manufacture of cavities by using electroforming techniques and on the development of techniques for the construction of electron guns. (author)

  9. Gain/bandwidth predictions for travelling-wave gyrotron

    Science.gov (United States)

    Sangster, A. J.

    1980-10-01

    Small signal gain computations based on a Pierce description of the traveling-wave gyrotron have been performed for cases involving beam voltages in the range 70-300 kV. Interactions at both the first and the second harmonics of the cyclotron resonance frequency have been considered in order to identify a range of operating parameters for the gyro-traveling-wave amplifier configuration which will potentially produce gain and bandwidth figures of significance to radar and communication systems operating at millimeter-wave frequencies. It is shown that when operated fundamentally and well away from cutoff, the gyro-traveling-wave amplifier can be magnetically tuned over a wide frequency range, with instantaneous bandwidths in the range 4-8% depending on the beam voltage; at voltages in excess of 200 kV, instantaneous bandwidths approaching 10% can be achieved.

  10. Development of dual frequency gyrotron and high power test of EC components

    Directory of Open Access Journals (Sweden)

    Sakamoto K.

    2012-09-01

    Full Text Available In JAEA, development of high-power long-pulse gyrotrons is underway. The output power of the gyrotron was applied for high-power long-pulse tests of the transmission line (TL and the equatorial launcher (EL mock up for ITER. The feature of design in the dual frequency gyrotron is the simultaneously satisfying the matching of both frequencies at a window and the same radiation angle at an internal mode convertor for both frequencies. The dual frequency gyrotron was developed and high power operations at 170 GHz and 137 GHz were carried out. The 170 GHz high power experiment of 40 m length ITER relevant TL was carried out and transmission efficiency and mode purity change caused by long pulse operation were measured. The mock-up model of EL was also tested using 170 GHz gyrotron. The power transmission through the quasi-optical beam line in EL was demonstrated using the full scale mock up model. Furthermore, the high power test results of the transmission components will be summarized.

  11. The 110 GHz Gyrotron Installation on DIII--D: Status and Experimental Results

    Science.gov (United States)

    Lohr, John; Ponce, Dan; Callis, R. W.; Popov, L.; Zerbini, M.; Cahalan, P.

    1997-11-01

    The 110 GHz installation on DIII--D consists of two gyrotrons each of which operates at generated power levels between 0.5 and 1.0 MW for pulse lengths up to 2.0 s. The gyrotrons are connected to DIII--D by windowless evacuated transmission lines. The greatest experience to date has been accumulated with the Gycom Centaur gyrotron, a diode tube which has been operated reliably at generated rf power levels in excess of 0.80 MW for pulse durations of 2.0 s. This tube has been modulated at 100% depth at frequencies up to 1 kHz. The second gyrotron is a Communications and Power Industries model VGT-8011A, a triode geometry, which is in initial testing. For this gyrotron, collector power loading has been measured, the beam steering has been set and pulse/power extension is in progress. DIII--D tests of the system performance are ongoing and initial tokamak experiments on transport, H--mode physics and scaling have begun.

  12. A 250 GHz gyrotron with a 3 GHz tuning bandwidth for dynamic nuclear polarization.

    Science.gov (United States)

    Barnes, Alexander B; Nanni, Emilio A; Herzfeld, Judith; Griffin, Robert G; Temkin, Richard J

    2012-08-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementing a long (23 mm) interaction cavity that can excite higher order axial modes by changing either the magnetic field of the gyrotron or the cathode potential. This interaction cavity excites the rotating TE(₅,₂,q) mode, and an internal mode converter outputs a high-quality microwave beam with >94% Gaussian content. The gyrotron was integrated into a DNP spectrometer, resulting in a measured DNP enhancement of 54 on the membrane protein bacteriorhodopsin. PMID:22743211

  13. A 250 GHz gyrotron with a 3 GHz tuning bandwidth for dynamic nuclear polarization

    Science.gov (United States)

    Barnes, Alexander B.; Nanni, Emilio A.; Herzfeld, Judith; Griffin, Robert G.; Temkin, Richard J.

    2012-08-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementing a long (23 mm) interaction cavity that can excite higher order axial modes by changing either the magnetic field of the gyrotron or the cathode potential. This interaction cavity excites the rotating TE5,2,q mode, and an internal mode converter outputs a high-quality microwave beam with >94% Gaussian content. The gyrotron was integrated into a DNP spectrometer, resulting in a measured DNP enhancement of 54 on the membrane protein bacteriorhodopsin.

  14. Experimental tests of a 263 GHz gyrotron for spectroscopic applications and diagnostics of various media

    Energy Technology Data Exchange (ETDEWEB)

    Glyavin, M. Yu., E-mail: glyavin@appl.sci-nnov.ru; Denisov, G. G.; Zapevalov, V. E. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Gycom Ltd., Nizhny Novgorod (Russian Federation); Chirkov, A. V.; Fokin, A. P.; Kholoptsev, V. V.; Kuftin, A. N.; Luchinin, A. G.; Golubyatnikov, G. Yu.; Malygin, V. I.; Morozkin, M. V.; Manuilov, V. N.; Proyavin, M. D.; Sedov, A. S.; Tsvetkov, A. I. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Sokolov, E. V.; Tai, E. M. [Gycom Ltd., Nizhny Novgorod (Russian Federation)

    2015-05-15

    A 263 GHz continuous-wave (CW) gyrotron was developed at the IAP RAS for future applications as a microwave power source in Dynamic Nuclear Polarization / Nuclear magnetic resonance (DNP/NMR) spectrometers. A new experimental facility with a computerized control was built to test this and subsequent gyrotrons. We obtained the maximum CW power up to 1 kW in the 15 kV/0.4 A operation regime. The power about 10 W, which is sufficient for many spectroscopic applications, was realized in the low current 14 kV/0.02 A regime. The possibility of frequency tuning by variation of the coolant temperature about 4 MHz/1 °C was demonstrated. The spectral width of the gyrotron radiation was about 10{sup −6}.

  15. High power operation of Gaussian beam gyrotron with CVD diamond window for JT-60U

    International Nuclear Information System (INIS)

    A 110 GHz-Gaussian beam output gyrotron with CVD (Chemical Vapor Deposition) diamond window was developed for the electron cyclotron heating and current drive on JT-60U. A stable Gaussian output beam power of 1.1 MW-0.1 s was obtained with the efficiency of 39% with depressed collector operation. Due to Gaussian beam output from the gyrotron, the coupling efficiency to HE11 mode in the mirror optical unit was 94%. Moreover, the transmission efficiency of 89% for HE11 mode was performed at the power level of 1 MW on the 40 m-transmission test line of φ31.751 mm corrugated waveguide and 8-miter bends included 1-pair of polarizer. The gyrotron and transmission line were installed into JT-60U system and 0.6 MW-0.3 s power was successfully injected into JT-60U plasmas as an initial operation

  16. Control of the Superconducting Magnets current Power Supplies of the TJ-II Gyrotrons

    International Nuclear Information System (INIS)

    The TJ-II ECRH heating system consists of two gyrotrons, which can deliver a maximum power of 300 kW at a frequency of 53.2 GHz. Another 28 GHz gyrotron is going to be used in the Bernstein waves heating system. In order to get the required frequency, the gyrotrons need and homogeneous magnetic field of several tesla, which is generated by a superconducting coil field by a current source. This document describes the current source control as well as the high precision ammeters control. These ammeters measure the current in the superconducting coils. The user interface and the programming of the control system are described. The communication between devices is also explained. (author) 9 Refs

  17. Status of the 2 MW, 170 GHz coaxial cavity gyrotron for ITER

    International Nuclear Information System (INIS)

    Full text: A 170 GHz coaxial cavity gyrotron with 2 MW output power in continuous wave (CW) operation is under development in cooperation between European research centres together with European industry. A first industrial prototype of such a gyrotron has already been fabricated and delivered to CRPP Lausanne, where a suitable test facility has been constructed. Due to a delay in fabrication the delivery of the gyrotron magnet is expected in May 2007. Thus experimental tests are expected for the second half of this year. In parallel to the industrial activities, experimental operation with a short pulse (∼ few ms) 170 GHz coaxial gyrotron ('pre-prototype') which uses the same main components as designed for the industrial tube has been continued. The mechanism of parasitic low frequency (LF) oscillations around 260 MHz has been identified. Based on this identification, small modifications of the geometry of the coaxial insert have been made. As a result the starting current for the LF oscillations has been increased by a factor of about 3 causing a strong reduction of the LF amplitude. Measurements with a prototype of a microwave load, which has been designed and fabricated for operation with the 2 MW prototype tube, have been performed. In addition to the distribution of the microwave power absorbed on the wall, the amount of power reflected back into the gyrotron has been measured and its influence on gyrotron performance has been investigated. The performance of the quasi optical (q.o.) RF output system presently installed in the industrial prototype tube is insufficient, mainly because of the low Gaussian content of the RF output beam. As a first step a new launcher with a different wall corrugation and a new adapted phase correcting mirror has been designed and fabricated. According to simulations an increase of the Gaussian content to about 87% is expected. This q.o. RF output system has been installed in the pre-prototype tube for performing hot

  18. Stable, high efficiency gyrotron backward-wave oscillator

    Science.gov (United States)

    Fan, C. T.; Chang, T. H.; Pao, K. F.; Chu, K. R.; Chen, S. H.

    2007-09-01

    Stability issues have been a major concern for the realization of broadband tunability of the gyrotron backward-wave oscillator (gyro-BWO). Multimode, time-dependent simulations are employed to examine the stability properties of the gyro-BWO. It is shown that the gyro-BWO is susceptible to both nonstationary oscillations and axial mode competition in the course of frequency tuning. Regions of nonstationary oscillations and axial mode competition are displayed in the form of stability maps over wide-ranging parameter spaces. These maps serve as a guide for the identification and optimization of stable windows for broadband tuning. Results indicate that a shorter interaction length provides greater stability without efficiency degradation. These theoretical predictions have been verified in a Ka-band gyro-BWO experiment using both short and long interaction lengths. In the case of a short interaction length, continuous and smooth tunability, in magnetic field and in beam voltage, was demonstrated with the high interaction efficiency reported so far. A maximum 3-dB tuning range of 1.3GHz with a peak power of 149kW at 29.8% efficiency was achieved. In a comparative experiment with a longer interaction length, the experimental data are characterized by piecewise-stable tuning curves separated by region(s) of nonstationary oscillations, as predicted by theory.

  19. Commissioning a Megawatt-class Gyrotron with Collector Potential Depression

    Science.gov (United States)

    Lohr, J.; Cengher, M.; Gorelov, Y. A.; Ponce, D.; Prater, R.

    2013-10-01

    A 110 GHz depressed collector gyrotron has been installed on the DIII-D tokamak. The commissioning process rapidly achieved operation at full parameters, 45 A and 94 kV total voltage, with 29 kV depression. Although short pulse, 2 ms, factory testing demonstrated 1.2 MW at 41% electrical efficiency, long pulse testing at DIII-D achieved only 33% efficiency at full power parameters, for pulse lengths up to 10 s. Maximum generated power was ~950 kW, considerably below the 1.2 MW target. During attempts to increase the power at 5 s pulse length, it was noted that the collector cooling water was boiling. This led to the discovery that 14 of the 160 cooling channels in the collector had been blocked by braze material during manufacture of the tube. The locations of blocked channels were identified using infrared imaging of the outside of the collector during rapid changes in the cooling water temperature. Despite these difficulties, the rf beam itself was of very high quality and the stray rf found calorimetrically in the Matching Optics Unit, which couples the Gaussian rf beam to the waveguide, was only 2% of the generated power, about half that of our previous best quality high power beam. Details of the power measurements and collector observations will be presented. Work supported by the US DOE under DE-FC02-04ER54698.

  20. Gyrotrons for High-Power Terahertz Science and Technology at FIR UF

    CERN Document Server

    Idehara, Toshitaka

    2016-01-01

    In this paper, we present the recent progress in the development of a series of gyrotrons at FIR UF that have opened the road to many novel applications in the high-power Terahertz science and technology. The current status of the research in this actively developing field is illustrated by the most representative examples in which the developed gyrotrons are used as powerful and frequency tunable sources of coherent radiation operating in a CW regime. Among them are high-precision spectroscopic techniques (most notably DNP-NMR, ESR, XDMR, and studies of the hyperfine splitting of the energy levels of positronium), treatment and characterization of advanced materials, new medical technologies.

  1. Infrared measurements of the synthetic diamond window of a 110 GHz high power Gyrotron

    International Nuclear Information System (INIS)

    Artificially grown diamond has extremely low absorption for microwaves in the millimeter wave range, making this material an attractive candidate for output windows on high power gyrotrons. Several windows have failed in this application due to higher than expected losses. Infrared measurements of the window temperature on a high power gyrotron operating at 110 GHz have been performed. The peak central temperature and time to equilibrium during the rf pulse were consistent with the low loss properties of the material determined from low power cavity measurements

  2. Design of 95 GHz, 2 MW Gyrotron for Communication and Security Applications

    Science.gov (United States)

    Kumar, Nitin; Singh, Udaybir; Singh, T. P.; Sinha, A. K.

    2011-02-01

    The design and the numerical simulation of the 95 GHz, 2 MW gyrotron for various kinds of communication, sensing and security applications is presented. The gyrotron is designed for the TE24,8 operating mode. Various in-house developed and commercially available computer codes are used for the design purpose. A 4.25 MW electron gun is designed for the 2 MW of output power. The mode selection, cold cavity and the beam-wave interaction analysis are discussed for the design of weakly tapered open resonator type of interaction cavity. The parametric analysis of the interaction cavity and the electron gun is also presented.

  3. Continuous-Wave Operation of a Frequency-Tunable 460-GHz Second-Harmonic Gyrotron for Enhanced Nuclear Magnetic Resonance

    OpenAIRE

    Torrezan, Antonio C.; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Griffin, Robert G.; Barnes, Alexander B.

    2010-01-01

    The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE11,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnet...

  4. Measurement of Radiation Frequency of Gyrotron by GaAs Schottky Barrier Diodes Coupled with Thin-Film Slot Antenna

    Science.gov (United States)

    Kosuke Hayashi,; Takashi Furuya,; Takashi Tachiki,; Takashi Uchida,; Toshitaka Idehara,; Yoshizumi Yasuoka,

    2010-03-01

    Thin-film slot-antenna-coupled GaAs Schottky barrier diodes (SBDs) used at the 180 GHz band were fabricated by microfabrication techniques, and the radiation frequency of a gyrotron at the University of Fukui (Gyrotron FU CW IV) was measured. In second-harmonic mixing using a local oscillator (LO) wave of 88.0899 GHz, an intermediate frequency (IF) signal of 102.8 MHz was observed and the radiation frequency of the gyrotron was found to be 176.077 GHz.

  5. A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron

    Science.gov (United States)

    Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

    2016-09-01

    Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun.

  6. Start-Up Scenario in Gyrotrons with a Nonstationary Microwave-Field Structure

    Science.gov (United States)

    Nusinovich, G. S.; Yeddulla, M.; Antonsen, T. M., Jr.; Vlasov, A. N.

    2006-03-01

    Megawatt class gyrotrons operate in very high-order modes. Therefore, control of a gyrotron oscillator’s start-up is important for excitation of the desired mode in the presence of the many undesired modes. Analysis of such scenario using the self-consistent code MAGY [M. Botton , IEEE Trans. Plasma Sci. 26,ITPSBD0093-3813 882 (1998)10.1109/27.700860] reveals that during start-up not only mode amplitudes vary in time, but also their axial structure can be time dependent. Simulations done for a 1.5 MW gyrotron show that the excitation of a single operating TE22,6 mode can exhibit a sort of intermittency when, first, it is excited as a mode whose axial structure extends outside the interaction cavity, then it ceases and then reappears as a mode mostly localized in the cavity. This phenomenon makes it necessary to analyze start-up scenarios in such gyrotrons with the use of codes that account for the possible evolution of field profiles.

  7. CONDITIONING AND PROTECTION CIRCUITRY FOR EXTERNAL MODULATION OF A PREPROGRAMMED GYROTRON CATHODE VOLTAGE COMMAND WAVEFORM

    Energy Technology Data Exchange (ETDEWEB)

    PONCE,D; FERRON,J.R; LEGG,R.A

    2003-10-01

    OAK-B135 The modulating voltages applied to the DIII-D gyrotrons are controlled by reference signals which are synthesized by arbitrary waveform generators.These generators allow ECH operators to pre-program reference waveforms consisting of ramps, flat tops, and various modulation shapes. This capability is independent of the DIII-D central timing and waveform facilities, which provides the ECH operators operational flexibility. The waveform generators include an amplitude modulation input, providing a means to control the pre-programmed waveform externally. This input is being used to allow the DIII-D plasma control system (PCS) to control gyrotron power in response top selected feedback signals. As the PCS control signal could potentially modulate the gyrotrons beyond operational limits or otherwise in a manner leading to recalcitrant rf generation, the control signal is conditioned so that its effect upon the ECH pre-programmed reference waveform is limited by conditions set by the ECH operators. The design of the circuitry which restricts the range over which the PCS control signal may modulate the reference waveform will be discussed. Test and DIII-D experimental results demonstrating the utility and effectiveness of gyrotron power modulated by the PCS will be presented.

  8. Simulation tools for computer-aided design and numerical investigations of high-power gyrotrons

    Science.gov (United States)

    Damyanova, M.; Balabanova, E.; Kern, S.; Illy, S.; Sabchevski, S.; Thumm, M.; Vasileva, E.; Zhelyazkov, I.

    2012-03-01

    Modelling and simulation are essential tools for computer-aided design (CAD), analysis and optimization of high-power gyrotrons used as radiation sources for electron cyclotron resonance heating (ECRH) and current drive (ECCD) of magnetically confined plasmas in the thermonuclear reactor ITER. In this communication, we present the current status of our simulation tools and discuss their further development.

  9. To the theory of high-power gyrotrons with uptapered resonators

    International Nuclear Information System (INIS)

    In high-power gyrotrons it is desirable to combine an optimal resonator length with the optimal value of the resonator quality factor. In resonators with the constant radius of the central part, the possibilities of this combination are limited because the quality factor of the resonator sharply increases with its length. Therefore the attempts to increase the length for maximizing the efficiency leads to such increase in the quality factor which makes the optimal current too small. Resonators with slightly uptapered profiles offer more flexibility in this regard. In such resonators, one can separate optimization of the interaction length from optimization of the quality factor because the quality factor determined by diffractive losses can be reduced by increasing the angle of uptapering. In the present paper, these issues are analyzed by studying as a typical high-power 17 GHz gyrotron which is currently under development in Europe for ITER (http://en.wikipedia.org/wiki/ITER). The effect of a slight uptapering of the resonator wall on the efficiency enhancement and the purity of the radiation spectrum in the process of the gyrotron start-up and power modulation are studied. Results show that optimal modification of the shape of a slightly uptapered resonator may result in increasing the gyrotron power from 1052 to 1360 kW.

  10. A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron.

    Science.gov (United States)

    Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

    2016-01-01

    Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun. PMID:27609247

  11. 1 MW and long pulse operation of Gaussian beam output gyrotron with CVD diamond window for fusion devices

    International Nuclear Information System (INIS)

    A 110 GHz-Gaussian beam output gyrotron with chemical vapor deposition (CVD) diamond window was developed for electron cyclotron heating and current drive on JT-60U. A stable Gaussian output beam power of 1.0 MW for 2 s was obtained with depressed collector operation. The temperature at the center of the diamond window was stabilized at the ΔT∼25 K. Gaussian beam output from the gyrotron remarkably improved the coupling efficiency to the HE11 mode in the transmission waveguide. 94% of the gyrotron output power was coupled to the corrugated waveguide of 31.75 mm in diameter, via a matching optics unit with two mirrors. A combination of the Gaussian output and the diamond window are indispensable for high power gyrotron operation at more than 1 MW and efficient coupling to the transmission line

  12. Effects of electron beam parameters and velocity spread on radio frequency output of a photonic band gap cavity gyrotron oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ashutosh, E-mail: asingh.rs.ece@iitbhu.ac.in [Faculty of Physical Sciences, Institute of Natural Sciences and Humanities, Shri Ramswaroop Memorial University, Lucknow-Deva Road, Uttar Pradesh 225003 (India); Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Jain, P. K. [Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-09-15

    In this paper, the effects of electron beam parameters and velocity spread on the RF behavior of a metallic photonic band gap (PBG) cavity gyrotron operating at 35 GHz with TE{sub 041}–like mode have been theoretically demonstrated. PBG cavity is used here to achieve a single mode operation of the overmoded cavity. The nonlinear time-dependent multimode analysis has been used to observe the beam-wave interaction behavior of the PBG cavity gyrotron, and a commercially available PIC code “CST Particle Studio” has been reconfigured to obtain 3D simulation results in order to validate the analytical values. The output power for this typical PBG gyrotron has been obtained ∼108 kW with ∼15.5% efficiency in a well confined TE{sub 041}–like mode, while all other competing modes have significantly low values of power output. The output power and efficiency of a gyrotron depend highly on the electron beam parameters and velocity spread. The influence of several electron beam parameters, e.g., beam voltage, beam current, beam velocity pitch factor, and DC magnetic field, on the PBG gyrotron operations has been investigated. This study would be helpful in optimising the electron beam parameters and estimating accurate RF output power of the high frequency PBG cavity based gyrotron oscillators.

  13. Gyrotron: an application of the relativistic bunching of electrons to the generation of intense millimeter microwave radiation

    International Nuclear Information System (INIS)

    The cyclotron maser or gyrotron is capable of generating high power microwaves at millimeter wave frequencies for applications in fusion heating, radar astronomy and communications. Analytic and numerical simulation models are developed that describe the behavior of these devices under realistic laboratory conditions including the effects of circuit geometry, beam thermal spread, and mode competition. In Chapter 2, a generalized linear theory for the gyrotron is presented in the form of an integro-differential equation that can be solved within various circuit geometries thus describing gyro-amplifiers, gyro-oscillatory and gyroklystrons. In Chapter 3 a complete description of a finite size electromagnetic particle simulation model is presented that describes gyrotrons operating in a TE/sub mn/ waveguide mode. In Chapter 4 simulations and theoretical analysis are made of gyrotron amplifiers operating in the TE/sub 01/ mode. In Chapter 5 the linear eigenmodes and eigenfrequencies of gyrotron oscillators are examined. In Chapter 6 the experimental development of a GHz gyrotron is presented. Theoretical and numerical predictions of oscillation thresholds and efficiencies compare favorably with experimental data

  14. Comparison of Different Methods for Calculating Gyrotron Quasi-Optical Mode Converters

    Science.gov (United States)

    Gashturi, A. P.; Chirkov, A. V.; Denisov, G. G.; Paveliev, A. B.

    2013-01-01

    This paper presents the use of combination of three methods for calculation and synthesis of high-efficiency microwave mode converters, such as radiators of gyrotrons. The analytical method yields immediate estimates of mode converter dimensions, the Scalar Integral Equation (SIE) allows one to synthesize efficiently the optimal profile of the mode converter, and the most accurate Electric Field Integral Equation (EFIE) is used to check all transmission characteristics of the converter including calculations of reflection and cross-polarization. The combination of these three methods is an optimal for the mode converter design. Just so the launcher was designed for a quasi-optical mode converter used in the 60 GHz gyrotron in the TE7,3 operating mode. The simulation results agree well with the measured data. The paper also presents for the first time an accurate derivation of the SIE method.

  15. Gyrotrons for High-Power Terahertz Science and Technology at FIR UF

    Science.gov (United States)

    Idehara, Toshitaka; Sabchevski, Svilen Petrov

    2016-10-01

    In this review paper, we present the recent progress in the development of a series of gyrotrons at the Research Center for Development of Far-Infrared Region, University of Fukui, that have opened the road to many novel applications in the high-power terahertz science and technology. The current status of the research in this actively developing field is illustrated by the most representative examples in which the developed gyrotrons are used as powerful and frequency-tunable sources of coherent radiation operating in a continuous-wave regime. Among them are high-precision spectroscopic techniques (most notably dynamic nuclear polarization-nuclear magnetic resonance, electron spin resonance, X-ray detected magnetic resonance, and studies of the hyperfine splitting of the energy levels of positronium), treatment and characterization of advanced materials, and new medical technologies.

  16. Problem-Oriented Simulation Packages and Computational Infrastructure for Numerical Studies of Powerful Gyrotrons

    Science.gov (United States)

    Damyanova, M.; Sabchevski, S.; Zhelyazkov, I.; Vasileva, E.; Balabanova, E.; Dankov, P.; Malinov, P.

    2016-05-01

    Powerful gyrotrons are necessary as sources of strong microwaves for electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) of magnetically confined plasmas in various reactors (most notably ITER) for controlled thermonuclear fusion. Adequate physical models and efficient problem-oriented software packages are essential tools for numerical studies, analysis, optimization and computer-aided design (CAD) of such high-performance gyrotrons operating in a CW mode and delivering output power of the order of 1-2 MW. In this report we present the current status of our simulation tools (physical models, numerical codes, pre- and post-processing programs, etc.) as well as the computational infrastructure on which they are being developed, maintained and executed.

  17. Development and simulation of RF components for high power millimeter wave gyrotrons

    International Nuclear Information System (INIS)

    To test gyrotron RF components, efficient low-power generators for rotating high-order modes of high purity are necessary. Designs of generators for the TE15,3 mode at 84 GHz and for the TE31,8 mode at 168 GHz are presented and some preliminary test results are discussed. In addition, Toshiba gyrotron cavities at 168 GHz were analyzed for leakage of RF power in the beam tunnel. To decrease RF power leakage, the declination angle of the cut-off cavity cross section has to be decreased. A TE15,3 waveguide nonlinear uptaper is analyzed at 84 GHz as well as 168 GHz uptapers. Since the calculated conversion losses are slightly higher than designed value, an optimization of those uptapers may be required. (author)

  18. High-frequency gyrotrons and their application to tokamak plasma heating

    International Nuclear Information System (INIS)

    A comprehensive analysis of high frequency (100 to 200 GHz) and high power (> 100 kW) gyrotrons has been conducted. It is shown that high frequencies will be required in order for electron cyclotron radiation to propagate to the center of a compact tokamak power reactor. High power levels will be needed in order to ignite the plasma with a reasonable number of gyrotron units. In the first part of this research, a set of analytic expressions, valid for all TE cavity modes and all harmonics, is derived for the starting current and frequency detuning using the Vlasov-Maxwell equations in the weakly relativistic limit. The use of an optical cavity is also investigated

  19. Time-domain theory of gyrotron traveling wave amplifiers operating at grazing incidence

    International Nuclear Information System (INIS)

    Time-domain theory of the gyrotron traveling wave tube (gyro-TWT) operating at grazing incidence has been developed. The theory is based on a description of wave propagation by a parabolic equation. The results of the simulations are compared with experimental results of the observation of subnanosecond pulse amplification in a gyro-TWT consisting of three gain sections separated by severs. The theory developed can also be used successfully for a description of amplification of monochromatic signals

  20. Time domain analysis of a gyrotron traveling wave amplifier with misaligned electron beam

    International Nuclear Information System (INIS)

    This article develops a time-domain theory to study the beam-wave interaction in gyrotron traveling wave amplifier (gyro-TWA) with a misaligned electron beam. The effects of beam misalignment on the TE01 mode gyro-TWA operating at the fundamental are discussed. Numerical results show that the effect of misalignment is less obvious when the input power is larger, and the influences of misalignment on the stable gain and the stable time are basically opposite

  1. A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization

    OpenAIRE

    Barnes, Alexander B.; Nanni, Emilio A.; Herzfeld, Judith; Griffin, Robert G.; Temkin, Richard J.

    2012-01-01

    We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to excite solid effect transitions utilizing other radicals, without the need for sweeping the NMR magnetic field. Substantially improved tunability is achieved by implementin...

  2. Progress on the Development of High Power Long Pulse Gyrotron and Related Technologies

    International Nuclear Information System (INIS)

    Full text: In the development of a higher power dual-frequency gyrotron, a high order mode gyrotron, which permits to select the oscillation at 170 GHz or 137 GHz, has been fabricated and tested. Short pulse experiments (0.5 ms) were performed with 1.3 MW power output at more than 30% of the oscillation efficiency for both frequencies. In long pulse experiments, 760 kW/46%/60 s at 170 GHz and 540 kW/42%/20 s at 137 GHz are achieved. It is the first time long pulse experiments with the dual-frequency gyrotron/triode electron gun. Since the RF beam direction from the output window is designed to be almost the same for both frequencies, good power couplings to the transmission line, which are 96% for 170 GHz and 94% for 137 GHz, are obtained by using a pair of identical phase correcting mirrors. Pulse extension is underway aiming for > 1 MW at CW operation. A 5 kHz full power modulation experiment was performed using the 170 GHz gyrotron of TE31,8 mode oscillation. The 5 kHz full power modulation was achieved with the full beam modulation by employing a fast voltage switching between the anode and cathode of the triode type electron gun. This satisfies the requirement of ITER. For further improvement, an advanced anode power supply system is proposed to reduce the oscillation period of adjacent mode at the start-up phase of each pulse. (author)

  3. Modelling and simulation of new generation powerful gyrotrons for the fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Sabchevski, S [Institute of Electronics, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Zhelyazkov, I [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria)

    2007-04-15

    One of the important issues related with the cyclotron resonance heating (CRH) and current drive of fusion plasmas in thermonuclear reactors (tokamaks and stellarators) is the development of multi-megawatt class gyrotrons. There are generally three stages of the implementation of that task, notably (i) elaborating a novel generation of software tools for the physical modelling and simulation of such kind of gyrotrons, (ii) their computer aided design (CAD) and construction on the basis of the simulation's results, and finally, (iii) gyrotrons' testing in real experimental conditions. This tutorial paper concerns the first item-the development of software tools. In co-operation with the Institute for Pulsed Power and Microwave Technology at the Forschungszentrum Karlsruhe, Germany, and Centre de Recherches en Physique des Plasmas at Ecole Polytechnique Federale de Lausanne, Switzerland, we work on the conceptual design of the software tools under development. The basic conclusions are that the numerical codes for gyrotrons' modelling should possess the following essential characteristics: (a) portability, (b) extensibility, (c) to be oriented toward the solution of practical problems (i.e., elaborating of computer programs that can be used in the design process), (d) to be based on self-consistent 3D physical models, which take into account the departure from axial symmetry, and (e) ability to simulate time dependent processes (electrostatic PIC simulation) alongside with a trajectory analysis (ray tracing simulation). Here, we discuss how various existing numerical codes have to be improved and implemented via the advanced programming technologies for state-of-the-art computer systems including clusters, grid, parallel platforms, and supercomputers.

  4. Diffraction and Scattering in Launchers of Quasi-Optical Mode Converters for Gyrotrons

    OpenAIRE

    Flamm, Jens Hanspeter

    2012-01-01

    In this work different methods for the calculation of diffraction and scattering in launchers of quasi-optical mode converters for gyrotrons are compared, ranked and extended. The extension gives the opportunity to take a tapered average radius of the waveguide antenna into account. The comparison and the extension of the fast field calculation methods for component synthesis opens the possibility to reduce diffraction and stray radiation of reliable and powerful millimeter wave sources.

  5. Final Report for "Gyrotron Design and Evaluation using New Particle-in-Cell Capability"

    Energy Technology Data Exchange (ETDEWEB)

    David N Smithe

    2008-05-28

    ITER will depend on high power CW gyrotrons to deliver power to the plasma at ECR frequencies. However, gyrotrons can suffer from undesirable low frequency oscillations (LFO’s) which are known to interfere with the gun-region diagnostics and data collection, and are also expected to produce undesirable energy and velocity spread in the beam. The origins and processes leading to these oscillations are poorly understood, and existing gyrotron R&D tools, such as static gun solvers and interaction region models, are not designed to look at time-dependant oscillatory behavior. We have applied a time-domain particle-in-cell method to investigate the LFO phenomenon. Our company is at the forefront of smooth-curved-boundary treatment of the electromagnetic fields and particle emission surfaces, and such methods are necessary to simulate the adiabatically trapped and reflected electrons thought to be driving the oscillations. This approach provides the means for understanding, in microscopic detail, the underlying physical processes driving the low-frequency oscillations. In the Phase I project, an electron gun region from an existing gyrotron, known to observe LFO’s, was selected as a proof-of-principle geometry, and was modeled with the curved-geometry time-domain simulation tool, in order to establish the feasibility of simulating LFO physics with this tool on office-scale, and larger, parallel cluster computers. Generally, it was found to be feasible to model the simulation geometry, emission, and magnetic features of the electron gun. Ultimately, the tool will be used to investigate the origins and life cycle within the trapped particle population. This tool also provides the foundations and validation for potential application of the software to numerous other time-dependant beam and rf source problems in the commercial arena.

  6. Feasibility of ion temperature measurement with a gyrotron scattering alpha particle diagnostic

    International Nuclear Information System (INIS)

    Collective Thomson scattering can be used to diagnose localized ion temperature as well as alpha particle velocity distribution and density in a D-T burning tokamak. With one diagnostic beam a simultaneous, but independent, measure of the bulk ion temperature and alpha particle parameters can be made. Use of a long pulse, millimeter-wave gyrotron offers a significant margin in signal to noise ratio capability (√Δftau > 1000) not previously possible with lasers. 9 refs., 2 figs

  7. The Gyrotron: AN Application of the Relativistic Bunching of Electrons to the Generation of Intense Millimeter Microwave Radiation

    Science.gov (United States)

    Caplan, Malcolm

    The cyclotron maser or gyrotron is capable of generating high power microwaves at millimeter wave frequencies for applications in fusion heating, radar astronomy and communications. Analytic and numerical simulation models are developed which describe the behavior of these devices under realistic laboratory conditions including the effects of circuit geometry, beam thermal spread and mode competition. In Chapter 2, a generalized linear theory for the gyrotron is presented in the form of an integro-differential equation which can be solved within various circuit geometries thus describing gyro-amplifiers, gyro-oscillators and gyroklystrons. In Chapter 3 a complete description of a finite size electromagnetic particle simulation model is presented which describes gyrotrons operating in a TE(,mn) waveguide mode. The resulting computer code is a "stretched" version of a 1-3/2 D particle code which apart from modelling transient self-consistent wave beam dynamics includes the essential effects of arbitrary conducting boundaries without requiring a full 2D simulation. The code also allows simultaneous multi-mode interaction. In Chapter 4 simulations and theoretical analysis are made of gyrotron amplifiers operating in the TE(,01) mode to predict bandwidth gain and efficiency with particular attention to the stabilization of absolute instabilities through frequency selective loss. In Chapter 5 the linear eigenmodes and eigenfrequencies of gyrotron oscillators are examined including the effects of beam loading and circuit geometry. Oscillation threshold currents are obtained. The design analysis and predicted efficiencies of gyrotron oscillators operating in the TE(,021) mode with output powers of at least 200 kW are obtained from particle simulations. In Chapter 6 the experimental development of a GHz gyrotron is presented including the design of the magnetron injection gun, circuit, collector and window. Theoretical and numerical predictions of oscillation thresholds and

  8. Low Noise Amplifiers for 140 Ghz Wide-Band Cryogenic Receivers

    Science.gov (United States)

    Larkoski, Patricia V.; Kangaslahti, Pekka; Samoska, Lorene; Lai, Richard; Sarkozy, Stephen

    2013-01-01

    We report S-parameter and noise measurements for three different Indium Phosphide 35-nanometer-gate-length High Electron Mobility Transistor (HEMT) Low Noise Amplifier (LNA) designs operating in the frequency range centered on 140 gigahertz. When packaged in a Waveguide Rectangular-6.1 waveguide housing, the LNAs have an average measured noise figure of 3.0 decibels - 3.6 decibels over the 122-170 gigahertz band. One LNA was cooled to 20 degrees Kelvin and a record low noise temperature of 46 Kelvin, or 0.64 decibels noise figure, was measured at 152 gigahertz. These amplifiers can be used to develop receivers for instruments that operate in the 130-170 gigahertz atmospheric window, which is an important frequency band for ground-based astronomy and millimeter-wave imaging applications.

  9. A Research of 140-GHz Folded Rectangular Gro ove Waveguide Traveling-Wave Tub e

    Institute of Scientific and Technical Information of China (English)

    ZHANG Minghao; WEI Yanyu; YUE Lingna; GUO Guo; WANG Yuanyuan; SHI Xianbao; WANG Wenxiang

    2015-01-01

    A two-section Folded rectangular groove waveguide (FRGWG) Slow wave structure (SWS) Travel-ing wave tube (TWT) with large dimension of beam tunnel is studied. Compared with the Folded waveguide (FWG) under the same size parameters conditions, the interac-tion impedance and center frequency of the FRGWG are higher. The advantage is that a beam tunnel with large dimension can be applied to the FRGWG without the influence caused by signal decrease, reflection and oscil-lation. The microwave amplification capability based on beam-wave interaction is obtained through the particle-in-cell method. This circuit structure can produce an output power of over 100W ranging from 136 to 142GHz when the operation voltage and beam current are set as 18.4kV and 150mA, respectively, for a 95mm long circuit.

  10. Experimental Study Of A 1.5-mw, 110-ghz Gyrotron Oscillator

    CERN Document Server

    Anderson, J P

    2005-01-01

    This thesis reports the design, construction and testing of a 1.5 MW, 110 GHz gyrotron oscillator. This high power microwave tube has been proposed as the next evolutionary step for gyrotrons used to provide electron cyclotron heating required in fusion devices. A short pulse gyrotron based on the industrial tube design was built at MIT for experimental studies. The experiments are the first demonstration of such high powers at 110 GHz. Using a 96 kV, 40 A electron beam, over 1.4 MW was axially extracted in the design (TE22,6) mode in 3 μs pulses, corresponding to a microwave efficiency of 37%. The beam alpha, the ratio of transverse to axial velocity in the electron beam, was measured with a probe. At the high efficiency operating point the beam alpha was measured as 1.33. This value of alpha is less than the design value of 1.4, possibly accounting for the slightly reduced experimental efficiency. The output power and efficiency, as a function of magnetic field, beam voltage, and beam current, are in...

  11. Development of high power gyrotron and transmission line for ECH/ECCD system

    International Nuclear Information System (INIS)

    170 GHz, high power and long pulse gyrotron with CVD diamond output window (tanδ ≤ 1.4 x 10-4, σ = 1800 W/m/K) has successfully been developed. The operation of 0.45 MW-8.0 sec and of 0.52 MW-6.2 sec were performed. Temperature increase of the window center was 150 deg. C at the operation of 0.52 MW-6.2 sec, moreover, the increment saturated, which well agreed with the simulation result. No damage on the gyrotron window and the gyrotron itself was observed through the experiment. We have constructed the 40 m run transmission line to demonstrate the efficient transmission of high power and long pulse millimeter wave. The total transmission loss has been estimated as less than 18%, which includes the loss in mirror optical unit, assumed as 10%. The transmission efficiency, the mode purity and the polarization are mainly investigated in the high power transmission experiment. The diamond window assembly as tritium or vacuum barrier in a transmission line was fabricated for high pressure test. The disk was failed at pressure of 0.465 MPa, which is consistent with the material strength. (author)

  12. A 0.33-THz second-harmonic frequency-tunable gyrotron

    Science.gov (United States)

    Zheng-Di, Li; Chao-Hai, Du; Xiang-Bo, Qi; Li, Luo; Pu-Kun, Liu

    2016-02-01

    Dynamics of the axial mode transition process in a 0.33-THz second-harmonic gyrotron is investigated to reveal the physical mechanism of realizing broadband frequency tuning in an open cavity circuit. A new interaction mechanism about propagating waves, featured by wave competition and wave cooperation, is presented and provides a new insight into the beam-wave interaction. The two different features revealed in the two different operation regions of low-order axial modes (LOAMs) and high-order axial modes (HOAMs) respectively determine the characteristic of the overall performance of the device essentially. The device performance is obtained by the simulation based on the time-domain nonlinear theory and shows that using a 12-kV/150-mA electron beam and TE-3,4 mode, the second harmonic gyrotron can generate terahertz radiations with frequency-tuning ranges of about 0.85 GHz and 0.60 GHz via magnetic field and beam voltage tuning, respectively. Additionally, some non-stationary phenomena in the mode startup process are also analyzed. The investigation in this paper presents guidance for future developing high-performance frequency-tunable gyrotrons toward terahertz applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471007, 61531002, 61522101, and 11275206) and the Seeding Grant for Medicine and Information Science of Peking University, China (Grant No. 2014-MI-01).

  13. Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range

    Science.gov (United States)

    Idehara, Toshitaka; Sabchevski, Svilen Petrov

    2012-07-01

    Powerful sources of coherent radiation in the sub-terahertz and in the terahertz frequency range of the electromagnetic spectrum are necessary for a great and continuously expanding number of applications in the physical research and in various advanced technological processes as well as in radars, communication systems, for remote sensing and inspection etc.. In recent years, a spectacular progress in the development of various gyro-devices and in particular of the powerful high frequency (sub-terahertz and terahertz) gyrotron oscillators has demonstrated a remarkable potential for bridging the so-called terahertz power gap and stimulated many novel and prospective applications. In this review paper we outline two series of such devices, namely the Gyrotron FU Series which includes pulsed gyrotrons and Gyrotron FU CW Series which consist of tubes operated in a CW (continuous wave) or long pulse mode, both developed at the FIR FU Center. We present the most remarkable achievements of these devices and illustrate their applications by some characteristic examples. An outlook for the further extension of the Gyrotron FU CW Series is also provided.

  14. Experimental Research on a 1.5 MW, 110 GHz Gyrotron with a Smooth Mirror Internal Mode Converter

    Science.gov (United States)

    Tax, D. S.; Mastovsky, I.; Shapiro, M. A.; Temkin, R. J.; Torrezan, A. C.

    2010-11-01

    Megawatt gyrotrons are important for electron cyclotron heating (ECH) of fusion plasmas, including ITER. These gyrotrons should operate with high efficiency to reduce the prime power required and to ensure good reliability. The gyrotron efficiency is affected both by the physical principles that govern the device and the performance of components like the internal mode converter (IMC), which must convert the electromagnetic cavity mode into a Gaussian beam. An IMC consisting of a helically-cut launcher and three smooth curved mirrors, which is less susceptible to alignment errors than an IMC using mirrors with phase correcting surfaces, was recently tested on a 1.5 MW, 110 GHz, 3μs pulsed gyrotron operating in the TE22,6 mode, and an output beam with 95.8 ± 0.5 % Gaussian beam content was measured in both hot and cold tests. We are also examining the issue of mode competition in the gyrotron, which can limit the achievable output power and efficiency. The sequence of competing modes excited during the rise time of the voltage pulse has been measured and results are compared with the numerical simulation code MAGY. These results should provide a good test of the accuracy of the code.

  15. On the dependence of the efficiency of a 240 GHz high-power gyrotron on the displacement of the electron beam and on the azimuthal index

    Energy Technology Data Exchange (ETDEWEB)

    Dumbrajs, O. [Institute of Solid State Physics (ISSP), Association EUROATOM-University of Latvia, Kengaraga iela 8, LV-1063 Riga (Latvia); Avramidis, K. A.; Franck, J.; Jelonnek, J. [Karlsruhe Institute of Technology (KIT), Institute for Pulsed Power and Microwave Technology (IHM), Association EURATOM-KIT, Kaiserstrasse 12, 76131 Karlsruhe (Germany)

    2014-01-15

    Two issues in the cavity design for a Megawatt-class, 240 GHz gyrotron are addressed. Those are first, the effect of a misaligned electron beam on the gyrotron efficiency and second, a possible azimuthal instability of the gyrotron. The aforementioned effects are important for any gyrotron operation, but could be more critical in the operation of Megawatt-class gyrotrons at frequencies above 200 GHz, which will be the anticipated requirement of DEMO. The target is to provide some basic trends to be considered during the refinement and optimization of the design. Self-consistent calculations are the base for simulations wherever possible. However, in cases for which self-consistent models were not available, fixed-field results are presented. In those cases, the conservative nature of the results should be kept in mind.

  16. On the dependence of the efficiency of a 240 GHz high-power gyrotron on the displacement of the electron beam and on the azimuthal index

    International Nuclear Information System (INIS)

    Two issues in the cavity design for a Megawatt-class, 240 GHz gyrotron are addressed. Those are first, the effect of a misaligned electron beam on the gyrotron efficiency and second, a possible azimuthal instability of the gyrotron. The aforementioned effects are important for any gyrotron operation, but could be more critical in the operation of Megawatt-class gyrotrons at frequencies above 200 GHz, which will be the anticipated requirement of DEMO. The target is to provide some basic trends to be considered during the refinement and optimization of the design. Self-consistent calculations are the base for simulations wherever possible. However, in cases for which self-consistent models were not available, fixed-field results are presented. In those cases, the conservative nature of the results should be kept in mind

  17. 2.2 MW Operation of the European Coaxial-Cavity Pre-Prototype Gyrotron for ITER

    International Nuclear Information System (INIS)

    Full text: A 2 MW, CW, 170 GHz coaxial-cavity gyrotron for electron cyclotron heating and current drive in the International Thermonuclear Experimental Reactor (ITER) is under development within an European Gyrotron Consortium (EGYC*). To support the development of the industrial prototype of a CW gyrotron, a short pulse tube (pre-prototype) is used at KIT (former FZK) for experimental verification of the design of critical components, such as electron gun, beam tunnel, cavity and quasi-optical (q.o.) RF-output coupler. Significant progress was achieved recently. In particular, RF output power of up to 2.2 MW with 30% output efficiency has been obtained in single-mode operation at 170 GHz. Furthermore, an excellent quality of the RF output beam with ∼ 96% fundamental Gaussian mode content has been obtained by using a new quasi-optical RF output system. The verification of these results with computer simulations will be presented. (author)

  18. 500-fold enhancement of in situ 13C liquid state NMR using gyrotron-driven temperature-jump DNP

    Science.gov (United States)

    Yoon, Dongyoung; Soundararajan, Murari; Caspers, Christian; Braunmueller, Falk; Genoud, Jérémy; Alberti, Stefano; Ansermet, Jean-Philippe

    2016-09-01

    A 550-fold increase in the liquid state 13C NMR signal of a 50 μL sample was obtained by first hyperpolarizing the sample at 20 K using a gyrotron (260 GHz), then, switching its frequency in order to apply 100 W for 1.5 s so as to melt the sample, finally, turning off the gyrotron to acquire the 13C NMR signal. The sample stays in its NMR resonator, so the sequence can be repeated with rapid cooling as the entire cryostat stays cold. DNP and thawing of the sample are performed only by the switchable and tunable gyrotron without external devices. Rapid transition from DNP to thawing in one second time scale was necessary especially in order to enhance liquid 1H NMR signal.

  19. Study of a cylindrical cavity gyrotron, influence of power reflection and of the oscillation of a travelling mode

    International Nuclear Information System (INIS)

    The quality factor and oscillating mode of a gyrotron cavity are essential parameters to consider when trying to obtain a high power (>500 kW), high efficiency (∼50%) microwave source, which oscillates in a stable manner in the principal mode of the cavity. The study and development of an 8 GHz gyrotron whose resonant cavity is formed by a cylindrical waveguide of slowly varying radius, is undertaken. The study is principally concerned with the phenomena associated with the low quality factor of the TEo011 mode of the cavity. (author) figs., tabs., 102 refs

  20. Coupler for coupling gyrotron whispering gallery mode RF into HE11 waveguide

    Science.gov (United States)

    Neilson, Jeffrey M

    2015-02-24

    A cylindrical waveguide with a mode converter transforms a whispering gallery mode from a gyrotron cylindrical waveguide with a helical cut launch edge to a quasi-Gaussian beam suitable for conveyance through a corrugated waveguide. This quasi-Gaussian beam is radiated away from the waveguide using a spiral cut launch edge, which is in close proximity to a first mode converting reflector. The first mode converting reflector is coupled to a second mode converting reflector which provides an output free-space HE11 mode wave suitable for direct coupling into a corrugated waveguide. The radiated beam produced at the output of the second mode converting reflector is substantially circular.

  1. Preliminary design of 1 MW, Ku-band gyrotron traveling-wave amplifier

    Institute of Scientific and Technical Information of China (English)

    Chongqing JIAO

    2009-01-01

    The preliminary design results ofa 1-MW, Ku-band gyrotron traveling wave amplifier (gyro-TWA) are presented. Operating at the second cyclotron harmonic of the TE11 mode, the amplifier characterizes good stability even in the case of no distributed losses loaded, which could potentially allow it to be operated at high average power. Large signal simulation shows that the amplifier can generate a saturated peak power of about 1 MW with efficiency of 26.6%, gain of 31 dB, and 3-dB bandwidth of about 1 GHz when driven by a 100 kV, 40 A electron beam with 5% axial velocity spread.

  2. Experiment for Over 200 kW Oscillation of a 295 GHz Pulse Gyrotron

    OpenAIRE

    YAMAGUCHI, YuuSuke; SAITO, Teruo; TATEMATSU, Yoshinori; IKEUCHI, Shinji; KASA, Jun; KOTERA, Masaki; Ogawa, Isamu; Idehara, Toshitaka; Kubo, Shin; SHIMOZUMA, Takashi; NISHIURA, Masaki; Tanaka, Kenji

    2013-01-01

    A high-power sub-THz gyrotron is under development as a power source of collective Thomson scatteringdiagnostic of fusion plasmas. It operates at a fundamental harmonic frequency of 295 GHz. A cavity whichrealizes stable and efficient single mode oscillation, an electron gun with an intense laminar electron beam, andan internal mode convertor are designed. A maximum oscillation power of 234kW is achieved with a Gaussianlike radiation pattern. The duration of 130kW pulse is extended up to 30 m...

  3. Experiment for over 200 kW oscillation of a 295 GHz pulse gyrotron

    International Nuclear Information System (INIS)

    A high-power sub-THz gyrotron is under development as a power source of collective Thomson scattering diagnostic of fusion plasmas. It operates at a fundamental harmonic frequency of 295 GHz. A cavity which realizes stable and efficient single mode oscillation, an electron gun with an intense laminar electron beam, and an internal mode convertor are designed. A maximum oscillation power of 234 kW is achieved with a Gaussian like radiation pattern. The duration of 130 kW pulse is extended up to 30 microseconds, which is limited by the configuration of power supply. (author)

  4. Development of problem-oriented software packages for numerical studies and computer-aided design (CAD) of gyrotrons

    Science.gov (United States)

    Damyanova, M.; Sabchevski, S.; Zhelyazkov, I.; Vasileva, E.; Balabanova, E.; Dankov, P.; Malinov, P.

    2016-03-01

    Gyrotrons are the most powerful sources of coherent CW (continuous wave) radiation in the frequency range situated between the long-wavelength edge of the infrared light (far-infrared region) and the microwaves, i.e., in the region of the electromagnetic spectrum which is usually called the THz-gap (or T-gap), since the output power of other devices (e.g., solid-state oscillators) operating in this interval is by several orders of magnitude lower. In the recent years, the unique capabilities of the sub-THz and THz gyrotrons have opened the road to many novel and future prospective applications in various physical studies and advanced high-power terahertz technologies. In this paper, we present the current status and functionality of the problem-oriented software packages (most notably GYROSIM and GYREOSS) used for numerical studies, computer-aided design (CAD) and optimization of gyrotrons for diverse applications. They consist of a hierarchy of codes specialized to modelling and simulation of different subsystems of the gyrotrons (EOS, resonant cavity, etc.) and are based on adequate physical models, efficient numerical methods and algorithms.

  5. Combined Hyperthermia and Photodynamic Therapy Using a Sub-THz Gyrotron as a Radiation Source

    Science.gov (United States)

    Miyoshi, Norio; Idehara, Toshitaka; Khutoryan, Eduard; Fukunaga, Yukihiro; Bibin, Andriana Bintang; Ito, Shinji; Sabchevski, Svilen Petrov

    2016-08-01

    In this paper, we present results of a hyperthermia treatment of malignant tumors using a gyrotron as a radiation source for heating of the cancerous tissue. They clearly demonstrate the efficiency of the irradiation by sub-THz waves, which leads to steady decrease of the volume of the tumor and finally to its disappearance. A combination of hyperthermia and photodynamic therapy (PDT) that utilizes a novel multifunctional photosensitizer has also been explored. In the latter case, the results are even more convincing and promising. In particular, while after a hyperthermia treatment sometimes a regrowth of the tumor is being observed, in the case of combined hyperthermia and PDT such regrowth has never been noticed. Another combined therapy is based on a preheating of the tumor by gyrotron radiation to temperatures lower than the hyperthermia temperature of 43 °C and followed then by PDT. The results show that such combination significantly increases the efficiency of the treatment. We consider this phenomenon as a synergy effect since it is absent when hyperthermia and PDT are applied separately, and manifests itself only when both methods are combined.

  6. Safety and protection of 8T NbTi gyrotron magnet in persistent mode

    International Nuclear Information System (INIS)

    Successful series of 5T cryomagnetic systems for additional high frequency plasma heating in Tokamaks T10 and T15, produced in Czechoslovakia during the last decade with the authors participation in magnet design and testing encouraged them to continue in further development of gyrotron magnets for further generation with operational field B0 = 8T. Approximately of the size and dimensions as was the case of previous 5T series, the 8T gyrotron magnet was designed as a part of preliminary work with preparations for ITER project. To achieve high mechanical stability of the superconducting winding, numerical stress-strain analyzes of winding structure and appropriate technology of epoxy impregnation were applied. To improve winding mechanical stability, initially round φ1 mm varnish insulated conductor was flattened to ''race track'' cross section (1.25 x 0.75 mm2 for inner section, respectively, 1.31 x 0.65 mm2 for the rest of magnet). Stainless steel road (φ1mm) of the bandage was flattened in the same way too (up to 1.14 x 0.77 mm2). Danger of creating a hot spot region has been limited by radial magnet sectioning and sections shunting by low ohmic shunts. Superconducting switch was protected by couple of antiparallel silicon diodes mounted between magnet flanges in parallel to it. High threshold voltages of diodes at 4.2K allow to run up system with relatively high speed without any limitation on sign of magnet field polarity

  7. Simulation of transient behavior in a pulse-line-driven gyrotron oscillator

    Science.gov (United States)

    Lin, A. T.; Lin, Chih-Chien; Yang, Z. H.; Chu, K. R.; Fliflet, A. W.

    1988-04-01

    Results are reported for a set of slow-time-scale single-mode and fast-time-scale single-mode and multimode simulations of the transient-mode excitation phenomena in a short-pulse high-peak-power Ka-band gyrotron oscillator experiment. Both the slow- and fast-time-scale single-mode simulations are generally in good agreement with each other and, within experimental uncertainties, with the experimental observations of the time dependence and magnetic-field dependence of 35-GHz emission in the TE62 mode. However, the multimode simulations suggest the presence of mode suppression, mode beating, and other nonlinear multimode phenomena that could not easily be observed in the experiment, and generally agree less well with the experimental measurements than the single-mode simulations. The multimode simulations also suggest that steady-state behavior may not be obtainable with the highly time-dependent voltage waveform employed in the experiment, and indicate the importance of carrying out future high-voltage gyrotron experiments with less highly transient voltage waveforms.

  8. Effect of ion compensation of the beam space charge on gyrotron operation

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

    2015-04-15

    In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

  9. Beam-wave interaction behavior of a 35 GHz metal PBG cavity gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ashutosh, E-mail: asingh.rs.ece@iitbhu.ac.in [Faculty of Physical Sciences, Institute of Natural Sciences and Humanities Shri Ramswaroop Memorial University, Lucknow-Deva Road, Uttar Pradesh-225003 (India); Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi-221005 (India); Jain, P. K. [Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi-221005 (India)

    2014-09-15

    The RF behavior of a 35 GHz photonic band gap (PBG) cavity gyrotron operating in TE{sub 041}-like mode has been presented to demonstrate its single mode operation capability. In this PBG cavity gyrotron, the conventional tapered cylindrical cavity is replaced by a metal PBG cavity as its RF interaction structure. The beam-wave interaction behavior has been explored using time dependent multimode nonlinear analysis as well as through 3D PIC simulation. Metal PBG cavity is treated here similar to that of a conventional cylindrical cavity for the desired mode confinement. The applied DC magnetic field profile has been considered uniform along the PBG cavity length both in analysis as well as in simulation. Electrons energy and phase along the interaction length of the PBG cavity facilitates bunching mechanism as well as energy transfer phenomena from the electron beam to the RF field. The RF output power for the TE{sub 041}-like design mode as well as nearby competing modes have been estimated and found above to 100 kW in TE{sub 041}-like mode with ∼15% efficiency. Results obtained from the analysis and the PIC simulation are found in agreement within 8% variation, and also it supports the single mode operation, as the PBG cavity does not switch into other parasitic modes in considerably large range of varying DC magnetic field, contrary to the conventional cylindrical cavity interaction structure.

  10. Upgrade Of The TH1506B 118 GHz Gyrotron Using Modeing Tools

    International Nuclear Information System (INIS)

    The first TH1506B prototype showing problems of overheating and spurious oscillations, a new modified gyrotron was built. During the tests, the extwo peaks, which was never predicted by simulations. Various low evel tests were performed on the mode converter with different shapes for the launcher but without real improvement. Besides measurements, the use of a new software Surf3D[l] showed that the problem mainly comes from the 3rd mirror whose curvature is too high and not well taken nto account by the calculation. This analysis software is based on ntegral equations and the complete 3D modelling alowed to determine a new profile for the 3rd mirror. An aluminium model of a new mirror was manufactured and thorough low level tests made at FZK showed that there was no double peak.The next step would consist in building a gyrotron based on this new design, to confirm the simulation and to valdate it for long pulses

  11. Characteristics of a superconducting magnet using a persistent current for a 110 GHz gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Maebara, Sunao; Kasugai, Atsushi; Sakamoto, Keishi; Tsuneoka, Masaki; Imai, Tsuyoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-03-01

    A superconducting magnet (SCM) using a persistent current for a 110 GHz gyrotron was developed to reduce liquid-helium loss, the boiled-off rate of 0.13 liter/hour was attained in a persistent current operation. It shows that the continuous operation for 50 days is capable without additional liquid-helium supply. Moreover, the 3040 liter in a year is used for a gyrotron test during five months and for the maintenance during seven months and liquid-helium savings of 65% was successfully demonstrated. The SCM is capable to excite the maximum magnetic field of 5.0 T in the persistent current mode. A mirror ratio between resonant cavity and magnetron injection gun (MIG) is 20 for operating the main coils in the persistent mode, since cavity coils and gun coils are connected in series. Auxiliary coils are equipped independently to control the mirror ratio, the mirror ratio of 13.6 - 37.0 at the 110 GHz is available. A two-stage refrigerator using helium gas was also installed and made liquid-nitrogen for cooling thermal shield of 80 K free. By developing this new type SCM, the number of routine works was drastically decreased in one time per 22-50 days, while routine works of a few times per week was needed up to now. (author).

  12. Electrical and thermo-mechanical analysis of beam recovery system for megawatt power gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Ranajoy, E-mail: joy_trm@yahoo.com [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India); Sahu, Naveen Kr [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India); Khan, Arani Ali [Department of Electronics and Communication, Indian Institute of Technology, Kharagpur (India); Khatun, Hasina; Sinha, A.K. [Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan 333031 (India)

    2013-05-15

    Highlights: • Electrical design of single stage depressed collector for high power gyrotron tube. • Efficiency enhancement by collecting spent beam. • Optimization of geometry and magnetic field for optimized beam spread. • Optimization of cooling duct system for better thermal management. -- Abstract: The paper presents the electrical and thermo-mechanical design of single stage beam recovery system for 120 GHz, 1 MW gyrotron. The electrical study shows that the cylindrical shape single stage beam recovery system enhances the efficiency by 66.26%. The maximum power deposited to collector in depressed collector operation is 0.48 MW for electronic efficiency, 30% and 1.44 MW for DC electron beam. The thermo-mechanical analysis has been performed to evaluate the water cooling system. The cooling system has capability of accommodating a peak wall loading, 0.9 kW/cm{sup 2} at flow rate of 1500 l/min for safe operating time, 60 ms. Further, a high voltage analysis is also carried out to appraise the electric field distribution in the collector.

  13. Nonlinear study of mode locking in a quasi-optical gyrotron

    Science.gov (United States)

    Wu, Hao; McCurdy, Alan H.

    1996-10-01

    Nonlinear, time-dependent multimode calculations have been carried out to study mode locking in quasi-optical gyrotron oscillators. The calculations are based on the rate equation model of modal growth and saturation. The slow-time formalism is used for particle motion and both the time varying electric and magnetic fields are included. It is found that radiation pulses of width 400 ps can be generated in nonlinear regime. The gyrotron features an open resonator of length 100 cm formed by a pair of spherical mirrors and a single pencil electron beam guided by external magnetic field in transverse direction to the axis of symmetry of the cavity. The strong current modulation is provided at frequency of 300 MHz, the nominal model spacing between two odd modes in such a cavity. Eight odd modes are found to be locked to generate extremely short radiation pulses. Application for short pulse radiation in millimeter and submillimeter wavelength range include radar, plasma diagnosis, time domain metrology and communication systems. Parametric dependencies investigated include static magnetic field, beam current and beam voltage, as well as the drive signal amplitudes and frequencies. The work is geared towards support of a proof of principle experiment to generate high power radiation pulses of short duration via synchronous mode locking.

  14. Continuous-Wave Operation of a Frequency-Tunable 460-GHz Second-Harmonic Gyrotron for Enhanced Nuclear Magnetic Resonance.

    Science.gov (United States)

    Torrezan, Antonio C; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J; Barnes, Alexander B; Griffin, Robert G

    2010-06-01

    The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE(11,2) and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE(11,2,q). The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:21243088

  15. Power-stabilization of high frequency gyrotrons using a double PID feedback control for applications to many high power THz spectroscopy

    OpenAIRE

    Kuleshov, Alexei; Ueda, Keisuke; Idehara, Toshitaka

    2013-01-01

    High stabilization of the output power of high frequency gyrotrons for high power THzspectroscopy is an important issue in order to extend the applications of gyrotrons to wider subjects.For this objective, we tried a PID feedback control on a heater current of a triode magnetroninjection gun (MIG) for stabilization of an electron beam current and an additional PID control ofan anode voltage of the gun for direct stabilization of output power. This double PID controlachieves effective respons...

  16. Formation of Multicharged Metal Ions in Vacuum Arc Plasma Heated by Gyrotron Radiation%Formation of Multicharged Metal Ions in Vacuum Arc Plasma Heated by Gyrotron Radiation

    Institute of Scientific and Technical Information of China (English)

    G. Yu. YUSHKOV; K. P. SAVKIN; A. G. NIKOLAEV; E. M. OKS; A.V. VODOPYANOV; I. V. IZOTOV; D. A. MANSFELD

    2011-01-01

    A new method for the generation of high charged state metal ion beams is developed. This method is based on microwave heating of vacuum arc plasma in a magnetic trap under electron cyclotron resonance (ECR) conditions. Two gyrotrons for plasma heating were used, which were with the following parameters. The first is with a wave frequency of 37.5 GHz, a pulse duration of 1 ms and power of 100 kW, another is with 75 GHz, 0.15 ms and 400 kW. Two different magnetic traps were considered for vacuum arc plasma confinement. The first one is a simple mirror trap. Such system was already investigated and could provide high charge state ions. The second trap was with a cusp magnetic field configuration with native "minimum-B" field structure. Two different ways of metal plasma injection into the magnetic trap were used. The first one is an axial injection from an arc source located out of the trap, and the second is a radial injection from four arc sources mounted at the center of the trap. Both traps provide up to 200 eMA of ion beam current for platinum ions with highest charge state 10+. Ion beams were successfully extracted from the plasma and accelerated by a voltage of up to 20 kV.

  17. ECRH transmission system

    International Nuclear Information System (INIS)

    The M.I.T. gyrotron group operates a 140 GHz, short pulse (1μs) gyrotron with output power, at present, of up to 175 kW. Output radiation has been obtained in several modes, including TE03 at 140 GHz, TE23 at 137 GHz, TE42 at 128 GHz and TE52 at 145 GHz. Studies have been carried out of the mode purity, both in frequency and in space, of gyrotron output radiation. These studies investigate parasitic mode excitation and mode conversion of gyrotron output power. Far field patterns of gyrotron radiation have been investigated to determine mode symmetry and purity. These results are useful in estimating the efficiency of various transmission systems. Finally, a new approach to quasi-optical transmission lines and mode converters, using axisymmetric optics, is suggested

  18. High-power, stable Ka/V dual-band gyrotron traveling-wave tube amplifier

    Science.gov (United States)

    Hung, Chien-Lun

    2012-05-01

    A dual-band amplifier can reduce the size, cost, and weight of a transmitter in dual-band radar and communication systems. This study proposes and theoretically investigates a gyrotron traveling-wave tube (gyro-TWT) amplifier capable of dual-band operation. Possible oscillations in the coaxial interaction waveguide are stabilized by the lossy inner cylinder. Under stable operating conditions, the gyro-TWT is predicted to provide a peak power of 375 kW with 71 dB saturated gain and 3.8 GHz bandwidth in the Ka-band and a peak power of 150 kW with 35 dB saturated gain and 1.7 GHz bandwidth in the V-band.

  19. 1 megawatt, 100 GHz gyrotron study. Final report, March 21-September 1, 1983

    International Nuclear Information System (INIS)

    This report provides the results of a design study on a gyrotron device employing a new type of hollow gyrobeam formation system and having a capability for delivering megawatt CW power at 100 GHz to an ECRH-heated, magnetically-confined plasma. The conceptual basis for the beam formation system is the tilt-angle gun (TAG) in which a conically-shaped electron beam is formed in a magnetically-shielded region and is then injected into the stray-field region of the main magnetic focusing system. Because fluid coolants can be accessed through the central pole of the TAG-type gun, rf interaction can be contemplated with cavity configurations not practical with the conventional MIG-type gyrobeam formation systems

  20. Systematic cavity design approach for a multi-frequency gyrotron for DEMO and study of its RF behavior

    Science.gov (United States)

    Kalaria, P. C.; Avramidis, K. A.; Franck, J.; Gantenbein, G.; Illy, S.; Pagonakis, I. Gr.; Thumm, M.; Jelonnek, J.

    2016-09-01

    High frequency (>230 GHz) megawatt-class gyrotrons are planned as RF sources for electron cyclotron resonance heating and current drive in DEMOnstration fusion power plants (DEMOs). In this paper, for the first time, a feasibility study of a 236 GHz DEMO gyrotron is presented by considering all relevant design goals and the possible technical limitations. A mode-selection procedure is proposed in order to satisfy the multi-frequency and frequency-step tunability requirements. An effective systematic design approach for the optimal design of a gradually tapered cavity is presented. The RF-behavior of the proposed cavity is verified rigorously, supporting 920 kW of stable output power with an interaction efficiency of 36% including the considerations of realistic beam parameters.

  1. Free-electron masers vs. gyrotrons prospects for high-power sources at millimeter and submillimeter wavelengths

    CERN Document Server

    Thumm, M K

    2002-01-01

    The possible applications of high-power millimeter (mm) and sub-mm waves from free-electron masers (FEMs) and gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power mm waves generated by long pulse or continuous wave (CW) gyrotron oscillators and short pulse very high-power FEMs in the areas of RF-plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as electron cyclotron resonance heating (28-170 GHz), electron cyclotron current drive , collective Thomson scattering , microwave transmission and heat-wave propagation experiments. Continuously frequency tunable FEMs could widen these fields of applications. Another important application of CW gyrotrons is industrial materials processing, e.g. sintering of high-performance functional and structural nanostructured ceramics. Sub-mm wave sources are employed in...

  2. Development of a dual frequency (110/138 GHz gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

    Directory of Open Access Journals (Sweden)

    Kobayashia Takayuki

    2015-01-01

    Full Text Available A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH and current drive (ECCD in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both frequencies. Cooling water temperatures in the gyrotron and matching optics unit were saturated in the 198 s oscillation, and the observed maximum water temperature is sufficiently low. In addition to the above activity on the dual-frequency gyrotron development, an oscillation (0.3 MW for 20 ms at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron. A possibility of the use of fundamental harmonic wave at 82 GHz in JT-60SA has been shown.

  3. Theoretical study on mode competition between fundamental and second harmonic modes in a 0.42 THz gyrotron with gradually tapered complex cavity

    International Nuclear Information System (INIS)

    In this paper, the nonlinear dynamics of mode competition in the complex cavity gyrotron are studied by using multi-frequency, time-dependent theory with the cold-cavity longitudinal profile approximation. Based on the theory, a code is written to simulate the mode competition in the gradually tapered complex cavity gyrotron operating at second harmonic oscillation. The simulations tracking seven competition modes show that single mode oscillation of the desired mode TE17.4 at 150 kW level can be expected with proper choice of operating parameters. Through studying on mode competition, it is proved that the complex cavity has a good capability for suppressing the mode competition. Meanwhile, it is found that TE17.3 could be excited in the first cavity as a competition mode when the gyrotron operating at large beam current, which leads to that TE17.3 and TE17.4 with different frequencies can coexist stably in the complex cavity gyrotron with very close amplitudes. Thus, the complex cavity might be used for multi-frequency output gyrotron

  4. Low-voltage harmonic multiplying gyrotron traveling-wave amplifier in G band

    International Nuclear Information System (INIS)

    Harmonic multiplying operation in a gyrotron traveling-wave amplifier (gyro-TWA) permits for magnetic field reduction and frequency multiplication. Lowering a beam voltage is an important step toward miniaturization of a harmonic multiplying gyro-TWA. However, the additional degree of freedom that is provided by the multitude cyclotron harmonics in a low-voltage harmonic multiplying gyro-TWA still easily generates various competing modes. An improved mode-selective circuit, using circular waveguides with various radii, can provide the rejection points within the frequency range to suppress competing modes. Simulated results reveal that the mode-selective circuit can provide an attenuation of more than 14 dB to suppress the competing modes. Furthermore, the performance of the gyro-TWA is analyzed for studying the sensitivity of the saturated output power and full width at half maximum bandwidth of the gyro-TWA to the beam voltage and the magnetic field. A stable low-voltage harmonic multiplying gyro-TWA with the mode-selective circuit is predicted to yield a peak output power of 24 kW at 200.4 GHz, corresponding to a saturated gain of 56 dB at an interaction efficiency of 20%. The full width at half maximum bandwidth is 3.0 GHz

  5. G-band harmonic multiplying gyrotron traveling-wave amplifier with a mode-selective circuit

    International Nuclear Information System (INIS)

    Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) permit for magnetic field reduction and frequency multiplication. A high-order-mode harmonic multiplying gyro-TWA with large circuit dimensions and low ohmic loss can achieve a high average power. By amplifying a fundamental harmonic TE01 drive wave, the second harmonic component of the beam current initiates a TE02 wave to be amplified. Wall losses can suppress some competing modes because they act as an effective sink of the energy of the modes. However, such wall losses do not suppress all competing modes as the fields are contracted in the copper section in the gyro-TWA. An improved mode-selective circuit, using circular waveguides with the specified radii, can provide the rejection points within the frequency range to suppress the competing modes. The simulated results reveal that the mode-selective circuit can provide an attenuation of more than 10 dB to suppress the competing modes (TE21, TE51, TE22, and TE03). A G-band second harmonic multiplying gyro-TWA with the mode-selective circuit is predicted to yield a peak output power of 50 kW at 198.8 GHz, corresponding to a saturated gain of 55 dB at an interaction efficiency of 10%. The full width at half maximum bandwidth is 5 GHz

  6. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    International Nuclear Information System (INIS)

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam

  7. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    Science.gov (United States)

    Ginzburg, N. S.; Zotova, I. V.; Sergeev, A. S.; Zaslavsky, V. Yu.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V.

    2015-11-01

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by "fresh" electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hardek, T.W.; Cooke, W.D.; Katz, J.D.; Perry, W.L.; Rees, D.E.

    1997-03-01

    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.

  9. Analysis and design of double-anode magnetron injection gun for 170 GHz gyrotron

    International Nuclear Information System (INIS)

    Based on adiabatic compression theory and electro-optical theory, a double-anode magnetron injection gun for 170 GHz gyrotron was designed. By theoretical analysis and calculations, using simulation software to simulate and optimize the electron gun, and got the result that the velocity ratio of electron beam was 1.31, the transverse velocity spread was 3.5% and the axial velocity spread was 7.1%, the beam current was 51 A. The effects of the cathode magnetic field, the control Jantage and the second anode Jantage on the properties of electron beam were discussed and found that electron beam were very sensitive with these factors. When cathode magnetic field increased, the velocity ratio of electron beam decreased, the axial velocity spread increased first and then decreased, the transverse velocity spread decreased first and then increased. The increase of the first anode Jantage could improve the velocity ratio and velocity spread of electron beam. The closer the anode angle and cathode angle, the smaller axial velocity spread. The transverse velocity spread became smaller while the anode angle changed toward the direction of reducing the distance between anode could cathode. When the two anode Jantage did not change, the increase of the distance between cathode and anode could minish the velocity spread of electron beam but the velocity ratio decreased at the same time. (authors)

  10. Dynamic nuclear polarization at 9 T using a novel 250 GHz gyrotron microwave source

    Science.gov (United States)

    Bajaj, V. S.; Farrar, C. T.; Hornstein, M. K.; Mastovsky, I.; Vieregg, J.; Bryant, J.; Eléna, B.; Kreischer, K. E.; Temkin, R. J.; Griffin, R. G.

    2011-12-01

    In this communication, we report enhancements of nuclear spin polarization by dynamic nuclear polarization (DNP) in static and spinning solids at a magnetic field strength of 9 T (250 GHz for g = 2 electrons, 380 MHz for 1H). In these experiments, 1H enhancements of up to 170 ± 50 have been observed in 1- 13C-glycine dispersed in a 60:40 glycerol/water matrix at temperatures of 20 K; in addition, we have observed significant enhancements in 15N spectra of unoriented pf1-bacteriophage. Finally, enhancements of ˜17 have been obtained in two-dimensional 13C- 13C chemical shift correlation spectra of the amino acid U- 13C, 15N-proline during magic angle spinning (MAS), demonstrating the stability of the DNP experiment for sustained acquisition and for quantitative experiments incorporating dipolar recoupling. In all cases, we have exploited the thermal mixing DNP mechanism with the nitroxide radical 4-amino-TEMPO as the paramagnetic dopant. These are the highest frequency DNP experiments performed to date and indicate that significant signal enhancements can be realized using the thermal mixing mechanism even at elevated magnetic fields. In large measure, this is due to the high microwave power output of the 250 GHz gyrotron oscillator used in these experiments.

  11. Low-order-mode harmonic multiplying gyrotron traveling-wave amplifier in W band

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Y. S.; Chen, C. H.; Yang, S. J.; Lai, C. H.; Lin, T. Y.; Lo, Y. C.; Hong, J. W. [Department of Electro-Optical Engineering, Southern Taiwan University, Tainan, Taiwan (China); Hung, C. L. [Department of Communication Engineering, National Penghu University of Science and Technology, Penghu, Taiwan (China); Chang, T. H. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China)

    2012-09-15

    Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) allow for magnetic field reduction and frequency multiplication. To avoid absolute instabilities, this work proposes a W-band harmonic multiplying gyro-TWA operating at low-order modes. By amplifying a fundamental harmonic TE{sub 11} drive wave, the second harmonic component of the beam current initiates a TE{sub 21} wave to be amplified. Absolute instabilities in the gyro-TWA are suppressed by shortening the interaction circuit and increasing wall losses. Simulation results reveal that compared with Ka-band gyro-TWTs, the lower wall losses effectively suppress absolute instabilities in the W-band gyro-TWA. However, a global reflective oscillation occurs as the wall losses decrease. Increasing the length or resistivity of the lossy section can reduce the feedback of the oscillation to stabilize the amplifier. The W-band harmonic multiplying gyro-TWA is predicted to yield a peak output power of 111 kW at 98 GHz with an efficiency of 25%, a saturated gain of 26 dB, and a bandwidth of 1.6 GHz for a 60 kV, 7.5 A electron beam with an axial velocity spread of 8%.

  12. Low-voltage harmonic multiplying gyrotron traveling-wave amplifier in G band

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Y. S.; Guo, Y. W.; Kao, B. H.; Chen, C. H.; Wang, Z. W. [Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Hung, C. L. [Department of Communication Engineering, National Penghu University of Science and Technology, Penghu, Taiwan (China); Chang, T. H. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China)

    2015-12-15

    Harmonic multiplying operation in a gyrotron traveling-wave amplifier (gyro-TWA) permits for magnetic field reduction and frequency multiplication. Lowering a beam voltage is an important step toward miniaturization of a harmonic multiplying gyro-TWA. However, the additional degree of freedom that is provided by the multitude cyclotron harmonics in a low-voltage harmonic multiplying gyro-TWA still easily generates various competing modes. An improved mode-selective circuit, using circular waveguides with various radii, can provide the rejection points within the frequency range to suppress competing modes. Simulated results reveal that the mode-selective circuit can provide an attenuation of more than 14 dB to suppress the competing modes. Furthermore, the performance of the gyro-TWA is analyzed for studying the sensitivity of the saturated output power and full width at half maximum bandwidth of the gyro-TWA to the beam voltage and the magnetic field. A stable low-voltage harmonic multiplying gyro-TWA with the mode-selective circuit is predicted to yield a peak output power of 24 kW at 200.4 GHz, corresponding to a saturated gain of 56 dB at an interaction efficiency of 20%. The full width at half maximum bandwidth is 3.0 GHz.

  13. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, N. S., E-mail: ginzburg@appl.sci-nnov.ru; Zaslavsky, V. Yu. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ul' yanov Str., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State University, 23 Gagarin Ave., 603950 Nizhny Novgorod (Russian Federation); Zotova, I. V.; Sergeev, A. S.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ul' yanov Str., 603950 Nizhny Novgorod (Russian Federation)

    2015-11-15

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

  14. Three-Dimensional Numerical Simulation of a 30-GHz Gyrotron Resonator With an Explicit High-Order Discontinuous-Galerkin-Based Parallel Particle-In-Cell Method

    DEFF Research Database (Denmark)

    Stock, Andreas; Neudorfer, Jonathan; Riedlinger, Marc;

    2012-01-01

    and the operating setup. For the first time, we apply a fully electromagnetic (EM) transient 3-D high-order discontinuous Galerkin particle-in-cell method solving the complete self-consistent nonlinear Vlasov–Maxwell equations to simulate a 30-GHz high-power millimeter-wave gyrotron resonator without physical......Fast design codes for the simulation of the particle–field interaction in the interior of gyrotron resonators are available. They procure their rapidity by making strong physical simplifications and approximations, which are not known to be valid for many variations of the geometry...

  15. Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

    OpenAIRE

    Kobayashia Takayuki; Moriyama Shinichi; Isayama Akihiko; Sawahata Masayuki; Terakado Masayuki; Hiranai Shinichi; Wada Kenji; Sato Yoshikatsu; Hinata Jun; Yokokura Kenji; Hoshino Katsumichi; Sakamoto Keishi

    2015-01-01

    A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both fre...

  16. Suppression of the Oscillatory Modes of a Space Charge in the Magnetron Injection Guns of Technological Gyrotrons

    Science.gov (United States)

    Glyavin, M. Yu.; Kuntsevich, A. D.; Manuilov, V. N.

    2015-01-01

    We present the results of based on the PIC method numerical simulation of the dynamic processes of trapping of electrons into the adiabatic trap of a technological gyrotron for different configurations of the electric and magnetic fields in the electron beam formation region. The electrode geometry providing a low reflection coefficient of the magnetic mirror to suppress oscillatory modes in the space-charge cloud and ensure the stability of the electron beam with a high fraction of oscillatory energy in such a system has been found.

  17. Development program for a 200 kW, CW gyrotron. Quarterly report No. 16, April-June 1983

    International Nuclear Information System (INIS)

    The objective of this program is the design and development of a millimeter-wave device to produce 200 kW of continuous wave power at 60 GHz. The device, a gyrotron oscillator, will be compatible with power delivery to an electron-cyclotron heated plasma. Smooth control of rf power over a 17 dB range is required, and the device should be capable of operation into a severely time-varying load mismatch. Progress is presented in the testing, analyses and understanding of S/N 1B behavior and in preparing S/N 3 for test in the coming report period

  18. 60 GHz gyrotron development program. Final report, April 1979-June 1984

    International Nuclear Information System (INIS)

    The original objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW CW power output at 110 GHz. The use of cyclotron resonance interaction was pursued, and the design phases of this effort are discussed. Later, however, the program's objective was changed to develop a family of oscillators capable of producing 200 kw of peak output power at 60 GHz. Gyrotron behavior studies were performed at 28 GHz to obtain generic design information as quickly as possible. The first experimental device at 60 GHz produced over 200 kw of peak power at a pulse duration of 20 μs. Heating problems and mode interference were encountered. The second experimental tube incorporated an optimized gun location but also suffered from mode interference. The third experimental tube included modifications that reduced mode interference. It demonstrated 200 kw of peak output at 100 ms pulse duration. The fourth experimental tube, which used an older rf circuit design but in a CW configuration, produced 71.5 kW CW. The fifth experimental tube incorporated a thinner double-disc output window which improved window bandwidth and reduced window loss. This tube also incorporated modifications to the drift tunnel and cavity coupling, which had proven successful in the third experimental pulse tube tests. It produced 123 kW of CW output power at 60 GHz rf load coolant boiling and tube window failure terminated the tests. A new waterload was designed and constructed, and alternative window designs were explored

  19. State-of-the-art of high power gyro-devices and free electron masers 1994

    International Nuclear Information System (INIS)

    At present, gyrotron oscillators are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. 140 GHz gyrotrons with output power Pout=0.54 MW, pulse length τ=3.0 s and efficiency η=42% are commercially available. Total efficiencies around 50% have been achieved using single-stage depressed collectors. Diagnostic gyrotrons deliver Pout=40 kW with τ=40 μs at frequencies up to 650 GHz (η≥4%). Recently, gyrotron oscillators have also been successfully used in material processing and plasma chemistry. Such technological applications require gyrotrons with the following parameters: f≥24 GHz, Pout=10-50 kW, CW, η≥30%. This paper reports on achievements and problems related to the development of very high power mm-wave gyrotrons for long pulse or CW operation and describes the microwave technological pecularities of the different development steps. In addition, this work gives a short overview of the present development of gyrotrons for technological applications, relativistic gyrotrons, quasi-optical gyrotrons, cyclotron autoresonance masers (CARMs), gyro klystrons, gyro-TWT amplifiers, gyrotwystron amplifiers, gyro-BWO's, peniotrons and free electron masers (FEMs). The most impressive FEM output parameters are: Pout=2 GW, τ=20 ns, η=13% at 140 GHz (LLNL) and Pout=15 kW, τ=20 μs, η=5% in the range from 120 to 900 GHz (UCSB). (orig.)

  20. Microwave generation for magnetic fusion energy applications, Task B

    International Nuclear Information System (INIS)

    One of the main issues in the development of high power gyrotrons is the present discrepancy between the theoretically predicted efficiency and that observed in the experiments. Recent 140 GHz experiments by MIT employed three cavities; two of the cavities have different interaction lengths and the third cavity is a complex two-section cavity. In all cases, the maximum experimental efficiency is well below the theoretically predicted one. A better theoretical understanding of the causes of these discrepancies is essential to the scaling of gyrotrons to higher power and higher frequency. We continued our investigation with the objective of determining whether mode competition and velocity spread in the electron beam could in some way be influencing the current result from the MIT 140 GHz gyrotrons experiments and determining to what extent these effects would influence operation of a 1 MW, 280 GHz, TE42,7 gyrotron as conceived at MIT. In our investigations, we used two models, the ''fixed axial field profile'' model and the ''self-consistent determination of the axial field profile'' model. With the ''fixed axial field profile'' model we studied the effect of thermal spread on the efficiency of gyrotrons operation, mode competition between unequally spaced modes, and we simulated the start up of the MIT 140 GHz gyrotrons. Our main conclusions from all these studies are discussed in this paper

  1. Free-electron masers vs. gyrotrons: prospects for high-power sources at millimeter and submillimeter wavelengths

    Science.gov (United States)

    Thumm, Manfred

    2002-05-01

    The possible applications of high-power millimeter (mm) and sub-mm waves from free-electron masers (FEMs) and gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power mm waves generated by long pulse or continuous wave (CW) gyrotron oscillators and short pulse very high-power FEMs in the areas of RF-plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as electron cyclotron resonance heating (28-170 GHz), electron cyclotron current drive , collective Thomson scattering , microwave transmission and heat-wave propagation experiments. Continuously frequency tunable FEMs could widen these fields of applications. Another important application of CW gyrotrons is industrial materials processing, e.g. sintering of high-performance functional and structural nanostructured ceramics. Sub-mm wave sources are employed in high-frequency broadband electron paramagnetic resonance and other types of spectroscopy. Future applications which await the development of novel high-power FEM amplifiers and gyro-amplifiers include high-resolution radar ranging and imaging in atmospheric and planetary science as well as deep-space and specialized satellite communications and RF drivers for next-generation high-gradient linear accelerators (supercolliders). The present paper reviews the state-of-the-art and future prospects of these recent applications of gyro-devices and FEMs and compares their specific advantages.

  2. Development Program for a 200-kW, c-w gyrotron. Quarterly report No. 14, October-December 1982

    International Nuclear Information System (INIS)

    The objective of this program is the design and development of a millimeter-wave device to produce 200 kW of continuous-wave power at 60 GHz. The device, a gyrotron oscillator, will be compatible with power delivery to an electron-cyclotron plasma. Smooth control of RF power output over a 17 dB range is required, and the device should be capable of operation into a severe time-varying load mismatch. Continued testing of S/N 1 A was limited by boiling in the water load. An efficiency of 48.9 percent was achieved at 3.3 amps cathode current. Extensive experimentation with eclectic water-load configurations was performed and significant progress was made toward a permanent load configuration. Testing was completed on S/N 2. This gyrotron had a limited operating range due to a nonconcentric cathode. After regunning, initial tests on S/N 2A produced 150 kW RF on the diagnostic modulator. Further investigation of a beam instability problem, which occurs under certain magnetic-field conditions, was performed on S/N 2A. Corrective action has been taken on S/N 3 to suppress this oscillation

  3. State-of-the-art of high power gyro-devices and free electron masers

    International Nuclear Information System (INIS)

    At present, gyrotron oscillators are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. 140 GHz gyrotrons with output power Pout = 0.58 MW, pulse length τ = 2.0 s and efficiency η = 34% are commercially available. Diagnostic gyrotrons deliver Pout = 40 kW with τ = 40 μs at frequencies up to 650 GHz (η ≥ 4%). Recently, gyrotron oscillators have also been successfully used in material processing and plasma chemistry. Such technological applications require gyrotrons with the following parameters: f ≥ 28 GHz, Pout = 10-30 kW, CW, η ≥ 30%. This paper reports on achievements and problems related to the development of very high power mm-wave gyrotrons for long pulse or CW operation and describes the microwave technological pecularities of the different development steps. In addition, this work gives a short overview of the present development of gyrotrons for technological applications, quasi-optical gyrotrons, cyclotron autoresonance masers (CARMs), gyro-klystrons, gyro-TWT amplifiers, gyro-BWO's and free electron masers (FEMs). The most impressive FEM output parameters are: Pout = 2 GW, τ = 20 ns, η = 13% at 140 GHz (LLNL) and Pout = 15 kW, τ = 20 μs, η = 5% in the range from 120 to 900 GHz (UCSB). (orig.)

  4. Effects of tapering structures on the characteristics of a coaxial-waveguide gyrotron backward-wave oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Hung, C. L. [Department of Communication Engineering, National Penghu University of Science and Technology, Penghu 880, Taiwan (China); Chang, T. H. [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China); Yeh, Y. S. [Department of Electro-Optical Engineering, Southern Taiwan University, Tainan 710, Taiwan (China)

    2011-10-15

    This study analyzes the characteristics of a gyrotron backward-wave oscillator (gyro-BWO) with a longitudinally tapered coaxial-waveguide by using a single-mode, self-consistent nonlinear code. Simulation results indicate that although tapering the inner wall or the outer wall can significantly raise the start-oscillation current, the former is more suitable for mode selection than the latter because an increase of the start-oscillation current by a tapered inner wall heavily depends on the chosen C value (i.e., the average ratio of the outer radius to the inner radius over the axial waveguide length). Selective suppression of the competing mode by tapering the inner wall is numerically demonstrated. Moreover, efficiency of the coaxial gyro-BWO is increased by tapering the outer wall. Properly down-tapering the outer wall ensures that the coaxial gyro-BWO can reach a maximum efficiency over twice that with a uniform one.

  5. Optimizing the coupling of output of a quasi-optical gyrotron owing to a diffraction grating with ellipsoidal support

    International Nuclear Information System (INIS)

    The output scheme of a quasi-optical gyrotron has been optimized in order to produce a gaussian output microwave beam suitable for transmission over long distances. The technique which has been applied consists of substituting one of the mirrors of the Fabry-Perot resonator in which the particle-wave interaction takes place by a diffraction grating placed in the -1 order Littrow mount and designed such that only orders -1 and 0 can propagate. In such a configuration, the diffraction angle of the order -1 coincides exactly with the incidence direction, thus providing a feedback in the cavity, whereas the order 0 constitutes the output of the resonator. A theoretical study of the power content in each diffracted order of a planar grating of infinite extent with equally spaced linear grooves as a function of the grating parameters has been performed. It has been shown that parameter domains can be found, which provide appropriate efficiencies in both orders for an application on a quasi-optical gyrotron. The Littrow condition was then adapted in order to match the spherical wavefronts of a gaussian beam incident on a possibly non-planar surface. The grooves become thus curvilinear and are no longer equally spaced. Measurements made on a cold test stand have confirmed the validity of the Littrow condition extension and allowed to determine its limits. It has also been shown that this type of cavity provides a mode having an optimal gaussian content and giving a minimal cavity transmission. The angular dispersion of the grating leads to a higher cavity transmission and to a slightly lower gaussian content for the adjacent resonator modes. The fundamental eigenmode electric field profile has been measured inside the cavity and is similar to that of an equivalent resonator made with two spherical mirrors. (author) figs., tabs., 141 refs

  6. Generation of electron beams in cyclotron motion and its interaction with electromagnetic fields in weakly irregular cavities: a study applied to conceptual elaboration of a 35 GHz gyrotron

    International Nuclear Information System (INIS)

    It is presented an investigation of different phenomena that occur in the gyrotron: 1) generation and transport of helical electron beams, 2) interaction of electrons in cyclotron motion with a transverse electric mode in resonant cavities operating near cutoff and 3) electron deposition over the collector active region. An exact ballistic model, which points out the nonlinear attributes of the relativistic equation of electron cyclotron motion and that includes a complex formulation for the longitudinal electric field distribution in weakly irregular waveguides, is used. Physically realizable RF field profiles are studied with the objective of maximizing gyrotron efficiency. For this purpose, an investigation is made of the resonant properties of truncated cones cavities and a new resonator type, with a profile described in terms of a continuous function, is developed. High perpendicular efficiencies (ηperpendicularMAX=0.86) have been calculated for interaction at the fundamental 1cyclotron harmonic and for uniform external magnetic field. A maximum efficiency scaling parameter S has been introduced, by which scaling relations ηperpendicularMAX= ηperpendicularMAX (S) are applicable to a variety of field profiles. The conceptual design of a 35 GHz gyrotron gives emphasis to selection criteria of operating parameters in compliance with technical constraints and with the requirement of soft self-excited oscillations. The proposed gyrotron operates in the azimuthally symetrical mode TE021 and is able to produce, with an electronic efficiency of 40%, an output power of 100 kW, in pulses of 20 ms, with a duty factor of 0.04%. (author)

  7. Control of the Superconducting Magnets current Power Supplies of the TJ-II Gyrotrons; Control de las Fuentes de Corriente de las Bobinas Superconductoras de los Girotrones del TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Ros, A.; Fernandez, A.; Tolkachev, A.; Catalan, G.

    2006-07-01

    The TJ-II ECRH heating system consists of two gyrotrons, which can deliver a maximum power of 300 kW at a frequency of 53.2 GHz. Another 28 GHz gyrotron is going to be used in the Bernstein waves heating system. In order to get the required frequency, the gyrotrons need and homogeneous magnetic field of several tesla, which is generated by a superconducting coil field by a current source. This document describes the current source control as well as the high precision ammeters control. These ammeters measure the current in the superconducting coils. The user interface and the programming of the control system are described. The communication between devices is also explained. (author) 9 Refs.

  8. A Stable 0.2-THz Coaxial-Waveguide Gyrotron Traveling-Wave-Tube Amplifier with Distributed Losses

    Science.gov (United States)

    Hung, C. L.; Yeh, Y. S.; Chang, T. H.; Fang, R. S.

    2016-08-01

    For high-power operation, a THz gyrotron traveling-wave-tube (gyro-TWT) amplifier must operate in a high-order waveguide mode to enlarge the transverse dimension of an interaction waveguide. However, a gyro-TWT amplifier operating in a high-order waveguide mode is susceptible to spurious oscillations. To improve the device stability, in this study, we investigate the possibility of using a coaxial waveguide with distributed losses as the interaction structure. For the same required attenuation, all threatening oscillating modes can be suppressed using different combinations of losses of inner and outer cylinders. This provides flexibility in designing distributed losses when considering the ohmic loading of the interaction structure. We predict that the 0.2-THz gyro-TWT can stably produce a peak power of 14 kW with an efficiency of 23 %, a 3-dB bandwidth of 3.5 GHz, and a saturated gain of 50 dB for a 20-kV 3-A electron beam with a 5 % velocity spread and 1.0 velocity ratio.

  9. Design and measurement of a TE13 input converter for high order mode gyrotron travelling wave amplifiers

    Science.gov (United States)

    Wang, Yan; Liu, Guo; Shu, Guoxiang; Yan, Ran; Wang, Li; Agurgo Balfour, E.; Fu, Hao; Luo, Yong; Wang, Shafei

    2016-03-01

    A technique to launch a circular TE13 mode to interact with the helical electron beam of a gyrotron travelling wave amplifier is proposed and verified by simulation and cold test in this paper. The high order (HOM) TE13 mode is excited by a broadband Y-type power divider with the aid of a cylindrical waveguide system. Using grooves and convex strips loaded at the lateral planes of the output cylindrical waveguide, the electric fields of the potential competing TE32 and TE71 modes are suppressed to allow the transmission of the dominant TE13 mode. The converter performance for different structural dimensions of grooves and convex strips is studied in detail and excellent results have been achieved. Simulation predicts that the average transmission is ˜-1.8 dB with a 3 dB bandwidth of 7.2 GHz (91.5-98.7 GHz) and port reflection is less than -15 dB. The conversion efficiency to the TE32 and TE71 modes are, respectively, under -15 dB and -24 dB in the operating frequency band. Such an HOM converter operating at W-band has been fabricated and cold tested with the radiation boundary. Measurement from the vector network analyzer cold test and microwave simulations show a good reflection performance for the converter.

  10. Stability analysis of a two-stage tapered gyrotron traveling-wave tube amplifier with distributed losses

    Energy Technology Data Exchange (ETDEWEB)

    Hung, C. L. [Department of Communication Engineering, National Penghu University of Science and Technology, Penghu 880, Taiwan (China); Lian, Y. H.; Cheng, N. H. [Graduate Institute of Electrical Engineering and Computer Science, National Penghu University of Science and Technology, Penghu 880, Taiwan (China); Yeh, Y. S. [Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan (China); Chang, T. H. [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2012-11-15

    The two-stage tapered gyrotron traveling-wave tube (gyro-TWT) amplifier has achieved wide bandwidth in the millimeter wave range. However, possible oscillations in each stage limit this amplifier's operating beam current and thus its output power. To further enhance the amplifier's stability, distributed losses are applied to the interaction circuit of the two-stage tapered gyro-TWT. A self-consistent particle-tracing code is used for analyzing the beam-wave interactions. The stability analysis includes the effects of the wall losses and the length of each stage on the possible oscillations. Simulation results reveal that the distributed-loss method effectively stabilizes all the oscillations in the two stages. Under stable operating conditions, the device is predicted to produce a peak power of 60 kW with an efficiency of 29% and a saturated gain of 52 dB in the Ka-band. The 3-dB bandwidth is 5.7 GHz, which is approximately 16% of the center frequency.

  11. High power rf amplifiers for accelerator applications: The large orbit gyrotron and the high current, space charge enhanced relativistic klystron

    Energy Technology Data Exchange (ETDEWEB)

    Stringfield, R.M.; Fazio, M.V.; Rickel, D.G.; Kwan, T.J.T.; Peratt, A.L.; Kinross-Wright, J.; Van Haaften, F.W.; Hoeberling, R.F.; Faehl, R.; Carlsten, B.; Destler, W.W.; Warner, L.B.

    1990-01-01

    Los Alamos is investigating a number of high power microwave sources for their potential to power advanced accelerators. Included in this investigation are the large orbit gyrotron amplifier and oscillator (LOG) and the relativistic klystron amplifier (RKA). LOG amplifier development is newly underway. Electron beam power levels of 3 GW, 70 ns duration, are planned, with anticipated conversion efficiencies into RF on the order of 20 percent. Ongoing investigations on this device include experimental improvement of the electron beam optics, and computational studies of resonator design and RF extraction. Recent RKA studies have operated at electron beam powers into the device of 1.35 GW in microsecond duration pulses. The device has yielded modulated electron beam power approaching 300 MW using 3--5 kW of RF input drive. RF powers extracted into waveguide have been up to 70 MW, suggesting that more power is available from the device that we have converted to-date in the extractor. We have examined several aspects of operation, including beam bunching phenomena and RF power extraction techniques. In addition, investigations of the amplifier gain as a function of input drive, electron beam parameters and axial magnetic field strength also have been explored. The effect of ions formed during device operation also has been considered.

  12. Automated Microwave Complex on the Basis of a Continuous-Wave Gyrotron with an Operating Frequency of 263 GHz and an Output Power of 1 kW

    Science.gov (United States)

    Glyavin, M. Yu.; Morozkin, M. V.; Tsvetkov, A. I.; Lubyako, L. V.; Golubiatnikov, G. Yu.; Kuftin, A. N.; Zapevalov, V. E.; V. Kholoptsev, V.; Eremeev, A. G.; Sedov, A. S.; Malygin, V. I.; Chirkov, A. V.; Fokin, A. P.; Sokolov, E. V.; Denisov, G. G.

    2016-02-01

    We study experimentally the automated microwave complex for microwave spectroscopy and diagnostics of various media, which was developed at the Institute of Applied Physics of the Russian Academy of Sciences in cooperation with GYCOM Ltd. on the basis of a gyrotron with a frequency of 263 GHz and operated at the first gyrofrequency harmonic. In the process of the experiments, a controllable output power of 0 .1 -1 kW was achieved with an efficiency of up to 17 % in the continuous-wave generation regime. The measured radiation spectrum with a relative width of about 10 -6 and the frequency values measured at various parameters of the device are presented. The results of measuring the parameters of the wave beam, which was formed by a built-in quasioptical converter, as well as the data obtained by measuring the heat loss in the cavity and the vacuum output window are analyzed.

  13. Rapid Sintering of Silica Xerogel Ceramic Derived from Sago Waste Ash Using Sub-millimeter Wave Heating with a 300 GHz CW Gyrotron

    Science.gov (United States)

    Aripin, Haji; Mitsudo, Seitaro; Sudiana, I. Nyoman; Tani, Shinji; Sako, Katsuhide; Fujii, Yutaka; Saito, Teruo; Idehara, Toshitaka; Sabchevski, Sliven

    2011-06-01

    In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics. It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm3 and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures and higher quality of the final product.

  14. State-of-the-art of high power gyro-devices and free electron masers. Update 2005

    International Nuclear Information System (INIS)

    Gyrotron oscillators (gyromonotrons) are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH), electron cyclotron current drive (ECCD), stability control and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. The maximum pulse length of commercially available 140 GHz, megawatt-class gyrotrons employing synthetic diamond output windows is 30 minutes (CPI and European FZK-CRPP-CEA-TED collaboration). The world record parameters of the European 140 GHz gyrotron are: 0.92 MW output power at 30 min. pulse duration, 97.5% Gaussian mode purity and 43% efficiency, employing a single-stage depressed collector for energy recovery. This results in an energy content of 1.66 GJ. A maximum output power of 1.2 MW in 4.1 s pulses was generated with the JAERI-TOSHIBA 110 GHz gyrotron. The Russian and the Japan 170 GHz ITER gyrotrons achieved 0.5 MW with pulse durations of 80 s and 500 s, respectively. Diagnostic gyrotrons deliver Pout=40 kW with τ=40 μs at frequencies up to 650 GHz (η=4%). Gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: f≥24 GHz, Pout=4-50 kW, CW, η≥30%. This paper gives an update of the experimental achievements related to the development of high power gyrotron oscillators for long pulse or CW operation and pulsed gyrotrons for plasma diagnostics. In addition, this work gives a short overview of the present development status of coaxial-cavity gyrotrons, gyrotrons for technological applications, relativistic gyrotrons, quasi-optical gyrotrons, fast- and slow-wave cyclotron autoresonance masers (CARMs), gyroklystrons, gyro-TWT amplifiers, gyrotwystron amplifiers, gyro-BWO's, gyropeniotrons, magnicons, gyroharmonic converters, free electron masers (FEMs) and of vacuum windows for such high-power mm-wave sources. The highest CW powers produced by

  15. Design of megawatt gyrotrons

    International Nuclear Information System (INIS)

    The design parameters of a 120 GHz gyromonotron capable of output powers in excess of 1 MW are determined. A nonlinear model of the interaction between the beam and rf field is used in which the efficiency is a function of only three normalized variables. By expressing the technological constraints in terms of these variables, permissible design parameters yielding high efficiency operation can be calculated. Constraints that are considered include ohmic heating of the walls, voltage depression of the beam, reduced coupling between the beam and rf field due to beam thickness, and efficiency degradation due to space charge forces within the beam. An analysis of the tradeoffs between current and voltage at the 1 MW level indicates that lower order modes can be utilized at lower voltages, but the constraints based on current limitations are difficult to satisfy. An 80 kV, 29 A design is presented that achieves a total efficiency of 44%. The primary uncertainty of these designs is the severity of competition due to parasitic modes. However, a number of isolated asymmetric modes appear capable of single mode emission at 1 MW based on present experimental results. Multimegawatt operation is also considered. It is shown that powers exceeding 20 MW are possible if single mode operation can be achieved in very high order modes. The methodology presented in this paper is general and can be easily adapted to other frequencies and output powers

  16. 170 GHz回旋管电子枪的设计%Design of the magnetron injection gun for 170 GHz gyrotron

    Institute of Scientific and Technical Information of China (English)

    曾旭; 王峨锋; 刘本田; 李志良; 冯进军

    2013-01-01

    A 170 GHz gryotron is an ideal power source for the Electron Cyclotron Resonance Heating (ECRH) in the plasma fusion. The required output power from a single gyrotron tube at 170 GHz operating frequency for ECRH application is 1 MW or more. For generating the high output power,a Magnetron Injection Gun(MIG) which can provide the electron beam with large enough transverse energy for interacting with the transverse filed of the electromagnetic wave is designed. Ideal parameters of the double-anode MIG are obtained according to the adiabatic compression theory and the correlative simulation software. The designed MIG can provide the necessary beams for the 170 GHz fundamental harmonic gyrotron under 80 kV of voltage and 40 A of current with the guidance center radius of 8.27 mm and the pitch factor of 1.5.%  170 GHz回旋管是等离子体核聚变中电子回旋谐振加热的理想功率源,在功率上要求具有1 MW以上的输出功率。要产生这么大的输出功率,就需要具有足够大横向能量的电子注与高频场的横向电场进行互作用,因此要对电子枪进行专门的设计。利用绝热压缩理论及相关的仿真软件对双阳极磁控注入电子枪进行了设计,得到了较好的电子注参数。所设计的电子枪能在工作电压80 kV、工作电流40 A 的条件下为170 GHz 基波回旋管提供所需的回旋电子注,其引导中心半径为8.27 mm,横纵速度比1.5。

  17. Backscattering of gyrotron radiation and short-wavelength turbulence during electron cyclotron resonance plasma heating in the L-2M stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Batanov, G. M.; Borzosekov, V. D., E-mail: tinborz@gmail.com; Kovrizhnykh, L. M.; Kolik, L. V.; Konchekov, E. M.; Malakhov, D. V.; Petrov, A. E.; Sarksyan, K. A.; Skvortsova, N. N.; Stepakhin, V. D.; Kharchev, N. K. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2013-06-15

    Backscattering of gyrotron radiation ({theta} = {pi}) by short-wavelength density fluctuations (k{sub Up-Tack} = 30 cm{sup -1}) in the plasma of the L-2M stellarator was studied under conditions of electron cyclotron resonance (ECR) plasma heating at the second harmonic of the electron gyrofrequency (75 GHz). The scattering of the O-wave emerging due to the splitting of the linearly polarized gyrotron radiation into the X- and O-waves was analyzed. The signal obtained after homodyne detection of scattered radiation is a result of interference of the reference signal, the quasi-steady component, and the fast oscillating component. The coefficients of reflection of the quasi-steady component, R{sub =}{sup 2}(Y), and fast oscillating component, R{sub {approx}}{sup 2}(Y), of scattered radiation are estimated. The growth of the R{sub {approx}}{sup 2}(Y) coefficient from 3.7 Multiplication-Sign 10{sup -4} to 5.2 Multiplication-Sign 10{sup -4} with increasing ECR heating power from 190 to 430 kW is found to correlate with the decrease in the energy lifetime from 1.9 to 1.46 ms. The relative density of short-wavelength fluctuations is estimated to be Left-Pointing-Angle-Bracket n{sub {approx}}{sup 2} Right-Pointing-Angle-Bracket / Left-Pointing-Angle-Bracket n{sub e}{sup 2} Right-Pointing-Angle-Bracket = 3 Multiplication-Sign 10{sup -7}. It is shown that the frequencies of short-wavelength fluctuations are in the range 10-150 kHz. The recorded short-wavelength fluctuations can be interpreted as structural turbulence, the energy of which comprises {approx}10% of the total fluctuations energy. Simulations of transport processes show that neoclassical heat fluxes are much smaller than anomalous ones. It is suggested that short-wavelength turbulence plays a decisive role in the anomalous heat transport.

  18. Further Characterization of 394-GHz Gyrotron FU CW GII with Additional PID Control System for 600-MHz DNP-SSNMR Spectroscopy

    Science.gov (United States)

    Ueda, Keisuke; Matsuki, Yoh; Fujiwara, Toshimichi; Tatematsu, Yoshinori; Ogawa, Isamu; Idehara, Toshitaka

    2016-09-01

    A 394-GHz gyrotron, FU CW GII, has been designed at the University of Fukui, Japan, for dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) experiments at 600-MHz 1H resonant frequency. After installation at the Institute for Protein Research (IPR), Osaka University, Japan, a PID feedback control system was equipped to regulate the electron gun heater current for stabilization of the electron beam current, which ultimately achieved stabilization of output power when operating in continuous wave (CW) mode. During exploration to further optimize operating conditions, a continuous tuning bandwidth of approximately 1 GHz was observed by varying the operating voltage at a fixed magnetic field. In the frequency range required for positive DNP enhancement, the output power was improved by increasing the magnetic field and the operating voltage from their initial operational settings. In addition, fine tuning of output frequency by varying the cavity cooling water temperature was demonstrated. These operating conditions and ancillary enhancements are expected to contribute to further enhancement of SSNMR signal.

  19. Further Characterization of 394-GHz Gyrotron FU CW GII with Additional PID Control System for 600-MHz DNP-SSNMR Spectroscopy

    Science.gov (United States)

    Ueda, Keisuke; Matsuki, Yoh; Fujiwara, Toshimichi; Tatematsu, Yoshinori; Ogawa, Isamu; Idehara, Toshitaka

    2016-04-01

    A 394-GHz gyrotron, FU CW GII, has been designed at the University of Fukui, Japan, for dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) experiments at 600-MHz 1H resonant frequency. After installation at the Institute for Protein Research (IPR), Osaka University, Japan, a PID feedback control system was equipped to regulate the electron gun heater current for stabilization of the electron beam current, which ultimately achieved stabilization of output power when operating in continuous wave (CW) mode. During exploration to further optimize operating conditions, a continuous tuning bandwidth of approximately 1 GHz was observed by varying the operating voltage at a fixed magnetic field. In the frequency range required for positive DNP enhancement, the output power was improved by increasing the magnetic field and the operating voltage from their initial operational settings. In addition, fine tuning of output frequency by varying the cavity cooling water temperature was demonstrated. These operating conditions and ancillary enhancements are expected to contribute to further enhancement of SSNMR signal.

  20. 94 GHz TE02模回旋管Vlasov模式变换器的设计与模拟%Design and Simulation of Vlasov Mode Converter for 94 GHz TE02 Mode Gyrotron

    Institute of Scientific and Technical Information of China (English)

    王斌; 杜朝海; 刘濮鲲; 耿志辉; 徐寿喜

    2011-01-01

    该文研究并设计了一个由Vlasov阶梯型开口辐射器、椭圆面反射器和抛物面反射器组成的TE02模回旋管准光模式变换器.首先采用几何光学研究了阶梯型开口辐射器、椭圆面反射器和抛物面反射器的具体形状,再利用矢量绕射理论分析了其工作过程,最后结合 94 GHz TE02模回旋管的具体参数,编写仿真程序详细讨论了工作模式在此模式变换器中的变换过程.模拟结果表明,94 GHz回旋管中的TE02模在输出窗处被转换为能量集中的准高斯波束,转换效率为78.35%.%The quasi-optical mode converter for the TE02 mode gyrotron, consisting of a Vlasov stepped-cut launcher,an elliptical reflector and a parabolic reflector, was designed, fabricated and studied. Firstly, the stepped-cut launcher, the elliptical reflector and the parabolic reflector were analytically evaluated with geometric optics. Next, the operation process of the converter was analyzed with vector diffra fion theory. And finally,operation of the mode conversion was simulated,based on the physical model of Vlasov mede converter for 94 GHz TE02 mode gyrotron. The simulated results show that the TE02 mode inside the 94 GHz gyrotron was converted into a higly Gaussian-like beam at the output window, and that the conversion efficiency was 78.35%.

  1. Observations of Regular Filamentary Plasma Arrays in High-Pressure Gas Breakdown by 1.5 MW, 110 GHz Gyrotron Pulses

    Science.gov (United States)

    Hidaka, Yoshiteru

    2008-11-01

    Formation of regular two-dimensional plasma filamentary arrays has been observed in long open-shuttered images of air breakdown at atmospheric pressure [Y. Hidaka et al., Phys. Rev. Lett. 100, 035003 (2008)]. The breakdown was generated by a focused linearly-polarized Gaussian beam from a 1.5-MW, 110-GHz gyrotron with a 3-microsecond pulse length. Each plasma filament is elongated in the electric field direction and separated roughly one-quarter wavelength from each other in the H-plane. The development of this array structure can be explained as a result of diffraction of the beam around the highly conductive filaments. The diffraction generates a new electric field profile in which a high intensity region emerges about a quarter wavelength upstream from an existing filament. A new plasma filament is likely to appear at the intensified spot. The same process continues and results in the formation of the observed array. Electromagnetic wave simulations that model plasma filaments as metallic posts agree quite well with the hypothesis above. With a nanoseconds-gated ICCD camera, we directly confirmed that only a few rows of the observed array are bright at any one moment, as well as that the light emitting region propagates towards the microwave source. Further experimental breakdown research has been carried out with nitrogen, helium, and SF6 at different pressures. Although each species exhibits qualitatively different structures, in general, a lumpy plasma at high pressures transforms into a more familiar, diffuse plasma as pressure is decreased. The propagation velocity of the ionization front has been also estimated both from the ICCD images and a photodiode array. The velocity is on the order of 10 km/s, and increases as the pressure decreases and the power density increases.

  2. 170 GHz兆瓦级同轴回旋振荡管的分析计算%Analysis and calculation of a 170 GHz megawatt-level coaxial gyrotron

    Institute of Scientific and Technical Information of China (English)

    覃觅觅; 罗勇; 杨阔; 黄勇

    2014-01-01

    回旋管是最有希望应用于正在实施的国际热核实验反应堆计划的微波源器件,然而研究设计符合要求的回旋管还存在很多困难需要解决.对170 GHz兆瓦级光滑同轴回旋管的注-波互作用进行了研究.选取模式谱相对稀疏的TE31,12作为工作模式,利用Matlab编制源程序,计算了同轴回旋管的注-波耦合系数、起振电流.在考虑电子速度零散、腔壁电阻率和单模近似的基础上,对光滑同轴谐振腔的优化设计和注-波互作用进行了仿真,给出了磁场、电压、电流和内导体倾角等参量与回旋管效率的关系.结果表明,电压和磁场对回旋管效率影响较大,电子速度零散对回旋管效率影响较小,因而可降低电子枪的设计要求.此外,优化内导体倾角和同轴谐振腔结构参数可提高注-波互作用效率,降低电子速度零散对互作用效率的影响,获得了约50%的电子效率及1.7 MW输出功率.%Gyrotrons are the most promising microwave source devices that can be used in the International Thermonuclear Experimental Reactor, but there are many diffculties to be solved in study and design of gyrotrons to meet the require-ments. In this paper, the beam-wave interactions of a 170 GHz megawatt-level smooth-wall coaxial gyrotron are studied numerically. In order to attain high effciency and stable radiation, TE31,12 mode that lies in a relative sparse spectrum is selected as the operating mode, and the beam-wave coupling coeffcient and start oscillation current are calculated by a set of source codes developed by Matlab. Taking into account the electronic velocity spread and cavity wall resistivity, and based on a single-mode approximation, the optimization design and simulation of beam-wave interaction of a 170 GHz megawatt smooth-wall coaxial gyrotron have been fulfilled. The relationships between effciency and magnetic field, and the voltage, current, taper angle of insert, and other parameters are

  3. A MAGICTRAC [Microwave Antenna for Whispering-Gallery-Mode Conversion using a Twist Reflector Antenna Converter] design for the MTX [Microwave Tokamak Experiment] transport system

    International Nuclear Information System (INIS)

    A design of a MAGICTRAC (Microwave Antenna for Whispering-Gallery-Mode Conversion using a Twist Reflector Antenna Converter) device is presented for use on the MTX (Microwave Tokamak Experiment) transport system. The MAGICTRAC device, consisting of a mode converting waveguide taper and three metal reflectors, transforms the TE15,2 circular waveguide mode output of a VARIAN Associates 140 GHz gyrotron into a free-space Gaussian-like beam with >95% efficiency. Dimensions of the MAGICTRAC are chosen to produce a beam matched to the MTX quasi-optical transport system

  4. Évaluation de technologies organiques faibles pertes et d’impression plastique 3D afin de contribuer au développement de solutions antennaires innovantes dans la bande 60 GHz – 140GHz.

    OpenAIRE

    Bisognin, Aimeric

    2015-01-01

    The improvement of the capabilities of wireless communication devices (smartphone, tablets …) which require higher and higher data rate, leads to a significant increase of the data traffic needed by each end user. This strong consumer demand for higher data-rate and coverage is stressing a lot the capacity of existing cellular networks. In order to cope with this challenge, one of the most promising solution consists in a network densification based on the deployment of low-power and short-ra...

  5. [Time-Resolved XEOL Experiment System on BL14W1 at SSRF].

    Science.gov (United States)

    Zhang, Zhao-hong; Jiang, Zheng; Xue, Song; Zheng, Li-fang

    2015-08-01

    A novel time-resolved X-ray excited optical luminescence (TRXEOL) experiment system was developed for X ray absorption fine structure spectroscopy(XAFS) beamline at Shanghai Synchrotron Radiation Facility (SSRF). The TRXEOL system is composed of three parts: timing system, spectrometer system and nuclear instrument module (NIM) system. These three systems were integrated to measure and record the optical luminescence from the sample excited by the synchrotron X-ray pulses, according to the time-correlated single photon counting methodology. It's the first time in the domestic synchrotron radiation facilities to achieve TRXEOL experiment using the synchrotron X-ray pulses and the time structure of the storage ring. In this work, a SSRF-self-developed timing system was used, which is based on the Field programmable Gate Array and the high-speed serial communication technology. The timing system can provide trigger pulse synchronized with the X-ray pulse. The timing jitter is about 6 ps, and the timing delay resolution is 5 ps. The NIM system is the core of the TRXEOL experiment system, it has three main modules: the Constant Fraction Discriminator (CFD), the Time to Amplitude Converter (TAC) and the Multi-Channel Analyzer (MCA). During one excitation circle, the spectrometer and the Photomultiplier Tube detector translate the induced luminescence of the sample excited by a single X-ray pulse into electrical pulse. The CFD module eliminates the timing walk larger than 50 ps induced by the amplitude of the electrical pulse. The TAC module calculates the time interval between the timing trigger pulse and the luminescence electrical pulse, and converts the interval into proportional amplitude of voltage. After plenty of circles, the MCA module gets the luminescence decay curve by recording and analyzing the voltage signals. And the data acquisition system gets the TRXEOL spectra by scanning the spectrometer and acquiring the frequency of the voltage pulses from the TAC module. The TRXEOL experiment system helps researchers measure optical decay curves and spectra of the sample in different time windows. Many luminescence behaviors would be explained more deeply, together with the aid of the optical XAFS to get the electron structure of the sample. A sample of ZnO nanowire was studied using the TRXEOL system. The ordinary XEOL spectrum obtained could distinguish the 390 nm wavelength and the 500 nm wavelength luminescence center. The decay curve at 0 nm wavelength could clearly show the fast luminescence process and the slow luminescence process. The full width at half maximum of the fast luminescence decay curve was about 0.5 ns, showing that the minimum time resolution of the TRXEOL system is less than 1 ns. The TRXEOL spectra obtained could respectively get the luminescence information within different time windows. It was demo nstrated that the TRXEOL system is not only feasible and reliable, but also supply XAFS beamline with the technical preparatio ns of time resolved techniques. PMID:26672318

  6. Characteristics of the light emission from CVD diamond windows

    International Nuclear Information System (INIS)

    Video and infrared signals were registered from brazed and bare CVD diamond disks forming the windows of an evacuated transmission cell placed into the beam line of a high power gyrotron facility at 140 GHz (Maquette tube). Intense light emission forming spot-like patterns, that was observed under vacuum conditions, has a broad maximum around 770 nm, which is attributed to light emitting processes of non-purely thermal nature. Carbon residues, likely of amorphous structure, which can be formed by decomposition of organic fibres, such as cellulose, are shown to be one source of this spectacular phenomenon. Here, no critical limitation is seen for the performance of high power diamond windows. (authors)

  7. Advanced electron cyclotron heating systems for next-step fusion experiments

    International Nuclear Information System (INIS)

    Electron cyclotron heating (ECH) is one of the major candidates for heating and current drive on ITER (170GHz) and W7-X (140GHz). ECH is extremely attractive from physics and reactor engineering points of view, offering start-up assist, efficient and localized power deposition, simple and compact launching structures with high injected power density, and a simple interface with shielding and blanket. High unit power (1MW or greater) and high efficiency (35% or greater) single-mode continuous-wave (CW) gyrotron oscillators are under development in order to reduce significantly the systems costs by reducing the size of the auxiliary support systems. 140GHz gyrotrons with 0.55MW output power in the Gaussian free-space TEM0,0 mode with a pulse length τ up to 3.0s and efficiency η of 42% are already commercially available (Gycom). Improved internal quasi-optical mode transducers generate the TEM0,0 output mode with efficiencies of 90-95% and separate the electron beam from the r.f. beam, thus allowing the use of large CW relevant depressed collectors for energy recovery. Tube efficiencies around 50% have been already achieved at JAERI and KfK. Face cooled double-disk sapphire windows, cryogenically edge-cooled single-disk sapphire windows (liquid-nitrogen, liquid-neon or liquid-helium cooling), distributed windows (metal or ceramics) as well as diamond and silicon windows are under investigation in order to solve the window problem. Long-distance high-power millimeter wave transmission from the source to the plasma device with very low ohmic losses and high mode purity can be accomplished by (1) a closed, highly overmoded, circumferentially corrugated or dielectrically lined, tubular HE1,1-hybrid mode waveguide and (2) open quasi-optical TEM0,0 transmission through a gaussian beam waveguide using focusing reflectors as phase-correcting elements. (orig.)

  8. Analyses of advanced concepts in multi-stage gyro-amplifiers and startup in high power gyro-oscillators

    Science.gov (United States)

    Sinitsyn, Oleksandr V.

    Gyrotrons are well recognized sources of high-power coherent electromagnetic radiation. The power that gyrotrons can radiate in the millimeter- and submillimeter-wavelength regions exceeds the power of classical microwave tubes by many orders of magnitude. In this work, the author considers some problems related to the operation of gyro-devices and methods of their solution. In particular, the self-excitation conditions for parasitic backward waves and effect of distributed losses on the small-signal gain of gyro-TWTs are analyzed. The corresponding small-signal theory describing two-stage gyro-traveling-wave tubes (gyro-TWTs) with the first stage having distributed losses is presented. The theory is illustrated by using it for the description of operation of a Ka-band gyro-TWT designed at the Naval Research Laboratory. Also, the results of nonlinear studies of this tube are presented and compared with the ones obtained by the use of MAGY, a multi-frequency, self-consistent code developed at the University of Maryland. An attempt to build a large signal theory of gyro-TWTs with tapered geometry and magnetic field profile is made and first results are obtained for a 250 GHz gyro-TWT. A comparative small-signal analysis of conventional four-cavity and three-stage clustered-cavity gyroklystrons is performed. The corresponding point-gap models for these devices are presented. The efficiency, gain, bandwidth and gain-bandwidth product are analyzed for each scheme. Advantages of the clustered-cavity over the conventional design are discussed. The startup scenarios in high-power gyrotrons and the most important physical effects associated with them are considered. The work presents the results of startup simulations for a 140 GHz, MW-class gyrotron developed by Communications and Power Industries (CPI) for electron-cyclotron resonance heating (ECRH) and current drive experiments on the "Wendelstein 7-X" stellarator plasma. Also presented are the results for a 110 GHz, 1

  9. High-power microwave transmission and launching systems for fusion plasma heating systems

    International Nuclear Information System (INIS)

    Microwave power in the 30- to 300-GHz frequency range is becoming widely used for heating of plasma in present-day fusion energy magnetic confinement experiments. Microwave power is effective in ionizing plasma and heating electrons through the electron cyclotron heating (ECH) process. Since the power is absorbed in regions of the magnetic field where resonance occurs and launching antennas with narrow beam widths are possible, power deposition location can be highly controlled. This is important for maximizing the power utilization efficiency and improving plasma parameters. Development of the gyrotron oscillator tube has advanced in recent years so that a 1-MW continuous-wave, 140-GHz power source will soon be available. Gyrotron output power is typically in a circular waveguide propagating a circular electric mode (such as TE0,2) or a whispering-gallery mode (such as TE15,2), depending on frequency and power level. An alternative high-power microwave source currently under development is the free-electron laser (FEL), which may be capable of generating 2-10 MW of average power at frequencies of up to 500 GHz. The FEL has a rectangular output waveguide carrying the TE0,1 mode. Because of its higher complexity and cost, the high-average-power FEL is not yet as extensively developed as the gyrotron. In this paper, several types of operating ECH transmission systems are discussed, as well systems currently being developed. The trend in this area is toward higher power and frequency due to the improvements in plasma density and temperature possible. Every system requires a variety of components, such as mode converters, waveguide bends, launchers, and directional couplers. Some of these components are discussed here, along with ongoing work to improve their performance. 8 refs

  10. High power microwave transmission systems for electron cyclotron resonance plasma heating

    International Nuclear Information System (INIS)

    This progress report is for the fourth year of a grant from the US Department of Energy for the design, development, and fabrication of ECRF transmission and mode conversion systems to transport microwave power from a gyrotron to a magnetically confined plasma. The development and testing of new and improved components for such systems and underlying theory, where necessary, is the focus of this project. Devising and improving component testing and diagnostic techniques is also an important part of this effort. During the last year, we developed a preliminary design for a Te15,2--TE15,1 mode converter for the MIT 150 GHz gyrotron and considered its performance as the frequency and mode was step tuned. A preliminary design for a combined uptaper and TE15,2--TE15,1 converter for possible use with the Varian 140 GHz gyrotron was also developed. Work was begun on a combined TE15,n uptaper -- mode converter to produce a mode combination which would reduce microwave radiation into an azimuthal waveguide gap. Simple models for the radiation from TE0n and TM0n Vlasov launcher baffles were developed and compared with measurements which were taken in our radiation pattern measurement facility. Work began on testing possible methods for generating high azimuthal index rotating modes. Work on the further refinement of the method of mode content determination from open-end radiation pattern measurement was carried out. An investigation of the Wiener-Hopf method for obtaining open- end radiation patterns produced improved radiation patterns for the TE0n modes in a circular waveguide. 15 refs., 15 figs

  11. RF calculation and thermal-stress analysis of the ECRH launcher on EAST tokamak

    International Nuclear Information System (INIS)

    Highlights: • The new constructing 140 GHz/1 MW/1000 s ECRH system was briefly introduced and the structure of ECRH launcher was detailedly described. • The transmission characteristics of the RF propagation inside the launcher were calculated and the Gaussian beam radius in the resonance layer of plasma was optimized. • Temperature distribution and thermal-stress of mobile mirror were analyzed. • The inner equivalent diameter of water channel in the mobile mirror and the suggested water velocity were analyzed. - Abstract: EAST is a medium sized superconducting tokamak with major radius R = 1.8 m, minor radius a = 0.45 m, plasma current Ip ≤ 1 MA, toroidal field BT ≤ 3.5 T and expected plasma pulse length up to 1000 s. An electron cyclotron resonance heating (ECRH) launcher for four-beam injection is being installed on EAST tokamak. Four electron cyclotron wave beams which are generated from four sets of 140 GHz/1 MW/1000 s gyrotrons will be injected into the plasma by the spherical focusing mirrors and plane mobile mirrors. The focusing mirrors are spherical to focus Gaussian beams after reflection. Four plane mobile mirrors independently steer continuously in the poloidal and toroidal direction controlled by motors. With the suitable distance between mirrors and appropriate focal length of focusing mirror, the beam radius in the resonance layer of plasma is 31.145 mm. The heat from plasma radiation and metal losses is loaded on the mobile mirror. In order to decrease the temperature and thermal stress, the inner equivalent diameter of water channels is 8 mm and the suggested water velocity is 4 m/s

  12. Research on long pulse ECRH system of EAST in support of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaojie, E-mail: xjiew@ipp.ac.cn; Liu, Fukun; Shan, Jiafang; Xu, Handong; Wu, Dajun; Li, Bo; Tang, Yunying; Zhang, Liyuan; Xu, Weiye; Hu, Huaichuan; Wang, Jiang; Yang, Yong; Xu, Li; Ma, Wendong; Feng, Jianqiang [Institute of Plasma Physics Chinese Academy of Sciences, Shushan lake road 350, 230031, Hefei (China); Wei, Wei [Institute of Plasma Physics Chinese Academy of Sciences, Shushan lake road 350, 230031, Hefei (China); Hefei University of Technology, 230009, Hefei (China)

    2015-12-10

    Experimental Advanced Superconducting Tokamak (EAST), as a fully superconducting tokamak in China, aims to achieve high performance plasma under steady-state operation. To fulfill the physical objectives of EAST, a program of 4-MW long pulse electron cyclotron resonance heating and current drive (EC H&CD) system, which would offer greater flexibility for plasma shape and plasma stabilization has been launched on EAST since 2011. The system, composed of 4 gyrotrons with nominal 1MW output power and 1000s pulse length each, is designed with the feature of steerable power handling capabilities at 140 GHz, using second harmonic of the extraordinary mode(X2). The missions of the ECRH system are to provide plasma heating, current drive, plasma profile tailoring and control of magneto-hydrodynamic (MHD) instabilities. Presently, the first two 140-GHz 1-MW gyrotrons, provided by GYCOM and CPI, respectively, have been tested at long pulse operation. The tubes, the associated power supplies, cooling system, cryogenic plant, 2 transmission lines and an equatorial launcher are now installed at EAST. The power generated from each tube will be transmitted by an evacuated corrugated waveguide transmission line and injected into plasma from the low field side (radial port) through a front steering equatorial launcher. Considering the diverse applications of the EC system, the beam’s launch angles can be continuously varied with the optimized scanning range of over 30° in poloidal direction and ±25° in toroidal, as well as the polarization could be adjusted during the discharge by the orientations of a pair of polarizers in the transmission line to maintain the highest absorption for different operational scenarios. The commissioning of the first 2MW ECRH plant for EAST is under way. The design, R&D activities and recent progress of the long pulse 140-GHz ECRH system are presented in this paper. As the technological requirements for EAST ECRH have many similarities with ITER

  13. Construction of a 35 GHz 100 kW gyrotron

    International Nuclear Information System (INIS)

    In this work a description of a 35 GHz 100 kW gyrocon is described which is under construction at the National Space Research Institute Plasma Laboratory. Project conceptual aspects are emphasized, specifically high current density thermionic cathodes, high time and spatial resolution intense magnetic fields generation, high-vacuum systems, techniques of ceramic-metal sealing, and high-voltage electrical modulator circuits. (author). 8 refs., 9 figs., 1 tab

  14. Summary on Electron Cyclotron Technology

    International Nuclear Information System (INIS)

    In EC 12, held in Aix-en-Provence on 13-15 May 2002, 24 papers addressed ECH technology oriented work. There were five status reports on systems currently in operation, being designed or in construction (JT60 (110 GHz), JET-EP (113 GHz), TS (118 GHz), TEXTOR and W7-X (40 GHz)), eight papers on power gyrotron development, six on subsystems or components development, three on windows, two on remote steering. About the systems still not operative, the cancellation of the JET DEP experiment is regrettable. On the other hand the W7-X ECH is perhaps the Stellarator subsystem in the most advanced state of development, and it can be already considered a future valuable test bench for the ITER EC system. In the area of gyrotron development, the best performance in terms of energy output and pulse length has been obtained by the 140 GHz FZK/EPFL/TED tube developed for W7-X, with pulses in the range of ∼ 0.5 MW for ∼ 200 s. Frequency and pulse performance of this tube are already in the range of ITER relevance. The sources at the nominal ITER frequency (170 GHz) have reached the nominal power level (∼1 MW) only for short pulses. However, the progress toward long pulses was delayed by accidents (loss of vacuum conditions because of overheating of an uncooled component in the Toshiba device and break of a diamond window in the Gycom tube). The reasons for these accidents are known and remedial actions already performed. A substantial progress on long pulse operation should be expected this year. An important progress achieved in gyrotron development is the control of stray radiation in the matching box by the use of radiation windows. Power modulation has become a recognized requirement for gyrotron sources. A further progress is however needed in order to preserve the nominal efficiency also at low power level, also in order to prevent thermal overloading of the collector. The electrical efficiency of the tubes is acceptable (∼ 50%) in short pulse but it generally de

  15. Preparation of Steady State Operation of the Wendelstein 7-X Stellarator

    International Nuclear Information System (INIS)

    Full text: Wendelstein 7-X has been designed to demonstrate the steady state capability of the stellarator concept. At 10 MW of heating power a pulse duration of 30 minutes is envisaged. Short pulses of additional heating power are foreseen to access beta and equilibrium limits and study fast ion confinement and fast ion driven instabilities. The large variety of time scales is strongly affecting the design of plasma diagnostics, heating and fuelling systems, data acquisition and device control. For steady state heating ten 1 MW continuous wave gyrotrons are foreseen, operating at 140 GHz second harmonic heating at 2.5 T. Using a system of mirrors, relaying the micro waves through air to Wendelstein 7-X, a very high transmission efficiency has been achieved. Front steering mirrors, one for each gyrotron, individually change the poloidal and toroidal launch angles, thus controlling the radial deposition and current drive. Recent modifications to the gyrotron design include an improved power handling in the collector using a rotating transverse magnetic field. The main heating scenarios are 2nd harmonic X-mode (X2) heating below the cut-off density of 1.2 x 1020 m-3 and 2nd harmonic O-mode (O2) heating at higher densities. Owing to non-absorbed power, significant levels of stray radiation are expected for O2-heating, during the transition from X2- to O2-heating, and also during plasma start-up with electron cyclotron resonance waves. Therefore all in-vessel components have to be qualified and if necessary protected to withstand up to 50 kW/m2 of continuous micro-wave power flux. Many diagnostic techniques require a specific adaptation or even new developments to cope with steady state operation. Besides the measurement of fast events, also the long times scales have to be covered. As a consequence not only data rates increase, but the total amount of data. This requires special efforts for real time plasma control, and for continuous data acquisition and data

  16. Periphery-Hydrogenating Effects on the Unordinary 14 w-Electron Delocalized Circuits and Related Electronic Properties of Subporphyrazine Analogs: A Density Functional Theory Investigation%Periphery-Hydrogenating Effects on the Unordinary 14 w-Electron Delocalized Circuits and Related Electronic Properties of Subporphyrazine Analogs: A Density Functional Theory Investigation

    Institute of Scientific and Technical Information of China (English)

    赵鲁阳; 齐冬冬; 蔡雪; 姜建壮

    2012-01-01

    Density functional theory method was employed to investigate the electronic properties of two series of sub- porphyrazine and subphthalocyanine derivatives, namely SubPz, SubPz-1H, SubPz-2H, SubPz-3H, SubPc, SubPc-1H, SubPc-2H, and SubPc-3H. Calculated results show that peripheral hydrogenation essentially changes the delocalized pattern from the common π14^14 to limited π13^14 or π12^14 for SubPz series, and substantially weakens the aromaticity for both SubPz and SubPc compounds. The unordinary delocalized circuit owns an unstable energy level, and thus gives rise to a notable transformation of geometric configuration, frontier molecular orbital topology, and absorption spectral bands.

  17. Qualifying plasma diagnostics for a high power microwave background of ECRH heated discharges

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, M.; Baldzuhn, J.; Endler, M.; Laux, M.; Zhang, D.; Laqua, H.P.; Noke, F.; Purps, F.; Ewert, K. [Max-Planck Institut fur Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Oosterbeek, J.W. [Technische Universiteit Eindhoven, Den Doelch 2, 5612 AZ Eindhoven (Netherlands); Jimenez, R. [Associacion EURATOM/CIEMAT, av. Complutense 22, 28040, Madrid (Spain)

    2011-07-01

    Microwave background radiation resulting from multiple reflected unabsorbed ECRH / ECCD power may cause severe problems for microwave absorbing in-vessel components such as gaskets, bellows, windows, isolators and cable insulations in particular during long pulse operation. For qualifying in-vessel components of W7-X in the environment of an isotropic 140 GHz radiation the Microwave Stray Radiation Launch facility, MISTRAL is operated at IPP. Power flux densities of 10-40 kW/m{sup 2} are obtained with a pulsed power gyrotron launching the microwave via a corrugated transmission line and a vacuum window to the MISTRAL vessel. The focus of the program was on cable isolations as required e.g. for in-vessel magnetic diagnostics. Sufficient shielding is obtained in nearly closed metal pipes only. Cryo pumps require a temperature < 12 K where Hydrogen desorption starts. The cryo pumps are usually shielded from plasma radiation by so called chevron structures. It is investigated whether coating of these chevrons with a microwave absorbing layer yields a sufficient reduction of the stray radiation level to ensure cryo pump operation. Diagnostic windows have been tested also. Although the temperature rise even of uncooled ZnSe and quartz windows at 10 kW/m{sup 2} is uncritical with respect to damage the associated refractive index changes may be too high for some diagnostic purposes e.g. for interferometry. A possible shielding are meshes or {mu}W absorbing coatings. Integrated diagnostic mock-ups such as for the diamagnetic loop, the inner Rogowski coils, Mirnov coils and the bolometer head also have been tested

  18. Overview on recent W7-AS results

    International Nuclear Information System (INIS)

    During the almost one year shutdown in 1999/2000 the Stellarator W7-AS underwent two major modifications: First, the limiters were replaced by ten divertor modules, and the diagnostic set associated with the plasma boundary and target plate regions was greatly expanded for divertor experiments. Extensive tests of the island divertor concept foreseen for W7-X were started in 2001. Partial plasma detachment is observed for magnetic field configurations with large edge islands and with high neutral beam heating power at core densities of 3x1020 m-3 . At somewhat lower densities stable discharges with good energy confinement and high radiation levels (mainly edge radiation) can be maintained up to pulse lengths of more than 1 s. Secondly, the previously counter tangential neutral beam injector box was shifted to a co-position. Thus, the heating efficiency is increased at low magnetic fields and high densities, where high-β experiments are usually performed, but where counter beam injection suffers from substantial fast ion losses. In first experiments - values up to about 3% were achieved at still only weak MHD-activity. Meanwhile 5 gyrotrons (70 and 140 GHz) are available on W7-AS with a total heating power of up to 2.5 MW. They were used to increase central electron temperatures up to 6.7 keV. The application of electron Bernstein waves was further investigated for plasma heating and as a plasma diagnostic. Heating of a high density divertor discharge and the measurement of electron temperature profiles are demonstrated. Copyright (2002) Australian National University- Research School of Physical Sciences and Engineering

  19. New Radiation Input/Output Systems for Millimeter-Wave Gyrotron Traveling-Wave Tubes

    Science.gov (United States)

    Denisov, G. G.; Bogdashov, A. A.; Gachev, I. G.; Mishakin, S. V.; Samsonov, S. V.

    2016-03-01

    We consider in detail the method allowing one to input and output the microwave radiation produced by an elecrovacuum amplifier through the same barrier window, which was proposed earlier, in the context of its application in a traveling-wave tube based on a waveguide with a helically corrugated surface. Special attention is given to the splitter of differently polarized radiation, and the results of studying this splitter at wavelengths of about 6 and 1 mm theoretically and experimentally are presented.

  20. Klystrons, traveling wave tubes, magnetrons, crossed-field amplifiers, and gyrotrons

    CERN Document Server

    Gilmour, A S

    2011-01-01

    Microwave tubes are vacuum electron devices used for the generation and amplification of radio frequencies in the microwave range. An established technology area, the use of tubes remains essential in the field today for high-power applications. The culmination of the author's 50 years of industry experience, this authoritative resource offers you a thorough understanding of the operations and major classes of microwave tubes.Minimizing the use of advanced mathematics, the book places emphasis on clear qualitative explanations of phenomena. This practical reference serves as an excellent intro

  1. Dynamic nuclear polarization at 9 T using a novel 250 GHz gyrotron microwave source

    OpenAIRE

    Bajaj, V. S.; Farrar, C. T.; Hornstein, M.K.; Mastovsky, I.; Vieregg, J.; Bryant, J; Eléna, B.; Kreischer, K.E.; Temkin, R.J.; Griffin, R G

    2003-01-01

    In this communication, we report enhancements of nuclear spin polarization by dynamic nuclear polarization (DNP) in static and spinning solids at a magnetic field strength of 9 T (250 GHz for g = 2 electrons, 380 MHz for [superscript 1]H). In these experiments, [superscript 1]H enhancements of up to 170 ± 50 have been observed in 1-[superscript 13]C-glycine dispersed in a 60:40 glycerol/water matrix at temperatures of 20 K; in addition, we have observed significant enhancements in [superscrip...

  2. Absorbing coatings for high power millimeter-wave devices and matched loads

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Bruschi, A.; Cirant, S. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Muzzini, V. [Istituto di Biologia Agro-ambientale e Forestale, Consiglio Nazionale delle Ricerche, Area di Ricerca di Roma 1, Monterotondo, Rome (Italy); Simonetto, A.; Spinicchia, N. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Angella, G. [Istituto per l’Energetica e le Interfasi, Consiglio Nazionale delle Ricerche, Milano (Italy); Dell’Era, F. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Gantenbein, G.; Leonhardt, W. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Nardone, A. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Samartsev, A.; Schmid, M. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2013-10-15

    Highlights: ► An overview of the activity at IFP-CNR concerning the absorbing coatings is presented. ► The application of the absorbing ceramics to the IFP-CNR matched loads is described. ► B{sub 4}C is presented as a promising material for power absorption in the EC frequency range. ► The most important high power validation tests performed on coatings are described. ► Some results from simulations of the absorption capability of a double layer coating are shown. -- Abstract: In the electron cyclotron frequency range the handling of high power is critical. In some cases an unpredictable amount of stray radiation can reach some components or accumulate in localized regions, with risk of damages caused by thermal overloads, and any uncontrolled reflection represents a danger for the sources. A possibility to mitigate the problem consists in covering some regions exposed to radiation with absorbers. Enhanced absorption of stray radiation lowers requirements on active protection systems in microwave diagnostics. The released heat can be extracted by dedicated cooling systems. The chromium oxide (Cr{sub 2}O{sub 3}), largely tested at IFP-CNR, has been routinely used as internal coating for matched loads. The performances of a variable thickness coating has been tested at high power at Karlsruhe Institute of Technology (KIT), with a 140 GHz gyrotron of the W7-X ECRH system and an averaged power density absorbed at the coating surface higher than 1 MW/m{sup 2} for 3 min. Also boron carbide (B{sub 4}C) has been tested at low power and patented as a millimeter-wave absorber. In the paper, the results of some tests performed on these coatings are given, together with some simulations of the absorption capability based on low power measurements on samples. Finally, some calculations are presented for a coating obtained combining together Cr{sub 2}O{sub 3} and B{sub 4}C.

  3. Modification of the collective Thomson scattering radiometer in the search for parametric decay on TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Salewski, Mirko; Bongers, W.;

    2012-01-01

    Strong scattering of high-power millimeter waves at 140 GHz has been shown to take place in heating and current-drive experiments at TEXTOR when a tearing mode is present in the plasma. The scattering signal is at present supposed to be generated by the parametric decay instability. Here we descr...

  4. Study on High Frequency Gyrotron Microwave Sintering of Nanoceramics%高频回旋管微波烧结纳米陶瓷研究

    Institute of Scientific and Technical Information of China (English)

    范瑛; 韦力凡; 丰杰; 谭云; 鞠炳全; 张卫庄

    2004-01-01

    在高频回旋管微波烧结系统上进行纳米陶瓷烧结研究,制备出氧化锆单元及二元纳米陶瓷样品,对不同烧结工艺制备出的样品做了密度、硬度测试,利用XRD和扫描电镜分析陶瓷样品晶粒特性,以摸索适宜的烧结工艺.探讨了高频回旋管微波烧结纳米陶瓷的可行性.

  5. Ech System on the Diii-D Tokamak

    Science.gov (United States)

    Gorelov, I. A.; Lohr, J.; Cengher, M.; Ponce, D.

    2009-04-01

    A significant upgrade to the 110 GHz DIII-D ECH system was completed last year. Two additional Communication and Power Industries (CPI) diode gyrotrons were installed and tested to half the designed pulse length of 10 s. For the 2008 experimental campaign, the DIII-D system comprised five long pulse CPI gyrotrons. One additional high voltage power supply is being tested to support operation of up to 6 gyrotrons simultaneously at full parameters. The five gyrotrons in operation have chemical-vapor-deposition (CVD) diamond windows that are monitored by infrared camera during full parameter testing and operation during plasma experiments. A sixth CPI gyrotron has been repaired after collector failure and is being conditioned for high power at DIII-D. New equipment for gyrotron collector heat load monitoring was tested and used to measure the collector power deposition profile. A new fast fault processing system based on FPGA technology is being commissioned.

  6. 100 GHz electrically tunable planar Bragg grating via nematic liquid crystal overlay towards reconfigurable WDM networks

    OpenAIRE

    Adikan, Faisal Rafiq Mahamd; Gates, James C.; Major, Huw E.; Gawith, Corin B.E.; Smith, Peter G. R.; Dyadyusha, Andriy; Kaczmarek, Malgosia; Sparrow, Ian J.G.

    2007-01-01

    Novel liquid crystal-based integrated optical devices with >140GHz electrical tuning are presented for application towards reconfigurable wavelength division multiplexing (WDM) networks. Initial results with Bragg wavelength tuning covering five 25GHz WDM channel spacing have been achieved with 170V (peak-to-peak) sinusoidal voltages applied across electro-patterned ITO-covered glass electrodes placed 60?m apart. These prototype devices were fabricated using direct UV grating writing, with an...

  7. Demonstration of 100 GHz electrically tunable liquid-crystal Bragg gratings for application in dynamic optical networks

    OpenAIRE

    Adikan, F.R.Mahamd; J.C.Gates; Dyadyusha, A.; Major, H.E.; Gawith, C.B.E.; Sparrow, I.J.G.; Emmerson, G.D.; Kaczmarek, M.; P.G.R.Smith

    2007-01-01

    We demonstrate liquid crystal-based integrated optical devices with >140GHz electrical tuning for potential applications in dynamic optical networks. Bragg wavelength tuning covering five 25GHz WDM channel spacings has been achieved with 170V (peak-to-peak) sinusoidal voltages applied across electro-patterned ITO-covered glass electrodes placed 60?m apart. This tunability range was limited only by the initial grating strength and supply voltage level. We also observed two distinct threshold b...

  8. GaAs single-drift flat-profile IMPATT diodes for CW operation at D band

    Science.gov (United States)

    Eisele, H.; Haddad, G. I.

    1992-01-01

    Single-drift flat-profile GaAs IMPATT diodes were designed for CW operation in the 140 GHz range. The diodes were fabricated from MBE grown material, mounted on diamond heatsinks, and tested in a radial line full height waveguide cavity. An RF output power of 15 mW with a corresponding DC to RF conversion efficiency of 1.5 percent was obtained at 135.3 GHz.

  9. Millimeter-wave brightness temperatures of military vehicles

    Science.gov (United States)

    Nemarich, Joseph; Cassidy, Thomas W.; Shiner, R.; Agravante, Hiroshi H.; Dixon, David; Moffa, Philip; Quon, Bill H.; Yujiri, Larry; Dahlstrom, R.

    1999-07-01

    Millimeter wave (MMW) radiometers operating at 97 and 140 GHz were used to obtain passive MMW images and brightness temperatures of military vehicles at various altitudes and depression angles. The line-scanning radiometer system used for the measurements is described, and several passive MMW images are presented. The upper-bound MMW brightness temperatures of a number of different types of vehicles in an open area were determined and shown to have similar values at various depression angles.

  10. Design of pill-box output window for high power Q-band gyrotron traveling wave tube%Q波段回旋行波管新型盒型输出窗的设计

    Institute of Scientific and Technical Information of China (English)

    陈辉; 王丽; 罗勇; 唐勇

    2015-01-01

    利用等效电路理论,初步设计了窗片厚度为1.32 mm的回旋行波管盒型输出窗,再加入感性膜片,更改窗片形状,最终设计出了能承受25 kW平均功率、相对带宽达到14%、窗片厚度达到1.7 mm的Q波段新型宽频带回旋行波管盒型输出窗;采用高频软件HFSS与有限元分析软件ANSYS协同仿真的新方法对回旋行波管盒型窗进行热特性研究表明,盒型窗理论上功率容量达到62 kW平均功率,说明输出窗窗片承受25 kW平均功率的可行性,窗片中心与边缘的温差为66℃,没有达到陶瓷窗片的临界温差158℃,验证了新型盒型窗设计的合理性.

  11. The DIII-D 3 MW, 110 GHz ECH system

    Science.gov (United States)

    Callis, R. W.; Lohr, J.; Ponce, D.; O'Neill, R. C.; Prater, R.; Luce, T. C.

    1999-09-01

    Three 110 GHz gyrotrons with nominal output power of 1 MW each have been installed and are operational on the DIII-D tokamak. One gyrotron is built by Gycom and has a nominal rating of 1 MW and a 2 s pulse length, with the pulse length being determined by the maximum temperature allowed on the edge cooled Boron Nitride window. The second and third gyrotrons were built by Communications and Power Industries (CPI). The first CPI gyrotron uses a double disc FC-75 cooled sapphire window which has a pulse length rating of 0.8 s at 1 MW, 2 s at 0.5 MW and 10 s at 0.35 MW. The second CPI gyrotron, utilizes a single disc chemical-vapor-deposition diamond window, that employs water cooling around the edge of the disc. Calculation predict that the diamond window should be capable of full 1 MW cw operation. All gyrotrons are connected to the tokamak by a low-loss-windowless evacuated transmission line using circular corrugated waveguide for propagation in the HE11 mode. Each waveguide system incorporates a two mirror launcher which can steer the rf beam poloidally from the center to the outer edge of the plasma. Central current drive experiments with the two gyrotrons with 1.5 MW of injected power drove about 0.17 MA. Results from using the three gyrotron systems will be reported as well as the plans to upgrade the system to 6 MW.

  12. Development of Mode Conversion Waveguides at KIT

    Directory of Open Access Journals (Sweden)

    Jin Jianbo

    2015-01-01

    Full Text Available The development of mode conversion waveguides (launchers for high power gyrotrons has gone through three stages at KIT. Formerly, harmonically deformed launchers have been used in the series gyrotrons developed for the stellarator W7-X. In 2009, a numerical method for the analysis and synthesis of mirror-line launchers was developed at KIT. Such a launcher with adapted mode-converting mirrors for a 2 MW TE34,19-mode, 170GHz coaxial-cavity gyrotron has been designed and tested, and also a mirror-line launcher for the 1MW EU ITER gyrotron has been designed. Recently, based on the Helmholtz-Kirchhoff integral theorem, a novel numerical method for the synthesis of hybrid-type gyrotron launchers has been developed. As an example, TE32,9 mode launchers operating at 170GHz that have been designed using the three different methods are being compared.

  13. Maturing ECRF technology for plasma control

    International Nuclear Information System (INIS)

    The availability of high power, (∼1 MW) long pulse length (effectively cw), high frequency, (>100 GHz) gyrotrons has opened the opportunity for enhanced scientific results on magnetic confinement devices for fusion research worldwide. This has led to successful experiments on electron cyclotron heating, electron cyclotron current drive, non-inductive tokamak operation, tokamak energy transport, suppression of instabilities and advanced profile control leading to enhanced performance. The key development in the gyrotron community that has led to the realization of high power long pulse gyrotrons is the availability of edge cooled synthetic diamond gyrotron output windows, which have low loss and excellent thermal and mechanical properties. In addition to the emergence of reliable high power gyrotrons, ancillary equipment for efficient microwave transmission over distances of hundreds of meters, polarization control, diagnostics, and flexible launch geometry have all been developed and proven in regular service. (author)

  14. Microwave generation for magnetic fusion energy applications

    International Nuclear Information System (INIS)

    This progress report encompasses work on three separate projects, all related to developing sources for electron cyclotron resonance heating of magnetic fusion plasmas. The report is therefore divided into three parts as follows: free electron lasers with small period wigglers; theory and modeling of high frequency, high power gyrotron operation; and depressed collectors for energy recovery in gyrotrons. Task A is experimental and eventually aims at developing CW sources for ECRH at frequencies as high as 600 GHz. Task B provides gyrotron theory and modeling in support of the gyrotron development programs at MIT and Varian. Task C was phased out in the current contract year but recent publications are included in this report in order to create a permanent record for the use of future researchers with interest in the topic of increasing gyrotron efficiency through the use of depressed collectors

  15. Design and operation of the power installation for the TCV ECR additional heating

    Energy Technology Data Exchange (ETDEWEB)

    Fasel, D.; Favre, A.; Goodman, T.; Henderson, M.; Isoz, P.F.; Perez, A.; Tran, M.Q. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP); Alex, J. [Thomcast AG, Turgi (Switzerland)

    1996-10-01

    Following a brief introduction to the TCV project, this paper concentrates on the Regulated High Voltage Power Supply (RHVPS) system chosen to supply the nine gyrotrons, distributed in three clusters, that will deliver 4.5 MW of Electron Cyclotron Resonance Heating (ECRH) to TCV plasmas. The configuration of these clusters is described in some detail, including the results of site test both with dummy load (80 kV, 85 A, 2 sec) and the gyrotrons themselves (70 kV, 25 A, 2 sec). Some details are also given of gyrotron auxiliaries, interlock circuitry, control and data acquisition, and integration into TCV control environment. (author) 4 figs., 1 tab., 4 refs.

  16. Millimeter-Wave Broadband Anti-Reflection Coatings Using Laser Ablation of Sub-Wavelength Structures

    CERN Document Server

    Matsumura, Tomotake; Wen, Qi; Hanany, Shaul; Koch, Jürgen; Suttman, Oliver; Schütz, Viktor

    2016-01-01

    We report on the first use of laser ablation to make sub-millimeter, broad-band, anti-reflection coatings (ARC) based on sub-wavelength structures (SWS) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with pitch of about 320 \\mu m and total height of near 800 \\mu m. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS ARC with the fabricated shape should have a fractional bandwidth response of $\\Delta \

  17. Broadband notch filter design for millimeter-wave plasma diagnostics

    DEFF Research Database (Denmark)

    Furtula, Vedran; Michelsen, Poul; Leipold, Frank;

    2010-01-01

    Notch filters are integrated in plasma diagnostic systems to protect millimeter-wave receivers from intensive stray radiation. Here we present a design of a notch filter with a center frequency of 140 GHz, a rejection bandwidth of ∼ 900 MHz, and a typical insertion loss below 2 dB in the passband...... in the cylindrical cavities is the fundamental TE11. The performance of the constructed filter is measured using a vector network analyzer monitoring a total bandwidth of 30 GHz. We compare the measurements with numerical simulations. © 2010 EURATOM...

  18. The Real-Time system for MHD activity control in the FTU tokamak

    Directory of Open Access Journals (Sweden)

    Minelli D.

    2012-09-01

    Full Text Available The Real-Time system for the control of the magnetohydrodynamics instabilities in FTU tokamak is presented. It is based on both a-priori information derived from statistical treatment of a database and Real-Time elaboration of live diagnostics data. The analysis codes are executed in different time threads based on multi-processors machines. The actuator is the 2×0.4MW 140 GHz ECRH system equipped with the new fast quasi-optical steerable launcher.

  19. EC-5 fifth international workshop on electron cyclotron emission and electron cyclotron heating

    Energy Technology Data Exchange (ETDEWEB)

    Prater, R.; Lohr, J. [eds.

    1985-12-31

    This report contains papers on the following topics: electron cyclotron emission measurements; electron cyclotron emission theory; electron cyclotron heating; gyrotron development; and ECH systems and waveguide development. These paper have been indexed separately elsewhere. (LSP).

  20. Dispersion of helically corrugated waveguides: Analytical, numerical, and experimental study

    Science.gov (United States)

    Burt, G.; Samsonov, S. V.; Ronald, K.; Denisov, G. G.; Young, A. R.; Bratman, V. L.; Phelps, A. D.; Cross, A. W.; Konoplev, I. V.; He, W.; Thomson, J.; Whyte, C. G.

    2004-10-01

    Helically corrugated waveguides have recently been studied for use in various applications such as interaction regions in gyrotron traveling-wave tubes and gyrotron backward-wave oscillators and as a dispersive medium for passive microwave pulse compression. The paper presents a summary of various methods that can be used for analysis of the wave dispersion of such waveguides. The results obtained from an analytical approach, simulations with the three-dimensional numerical code MAGIC, and cold microwave measurements are analyzed and compared.

  1. 300GHz 材料プロセッシング装置の開発

    OpenAIRE

    光藤, 誠太郎; 坂井, 和喜; 小林, 一生; 中野, 智彰; 出原, 敏孝; 斉藤, 輝雄

    2007-01-01

    High power THz-frequency material processing has great potential for the applications. The gyrotron is a microwave tube capable of delivering very high microwave power in the pulse and CW operation at the THz frequencies. The frequency of gyrotron is proportional to the intensity of magnetic field, because the operation results from the mechanism of “cyclotron resonance maser”. Therefore, in order to achieve high frequency operation, we need a high magnetic field which superconducting magne...

  2. Characterization of high-power RF structures using time-domain field codes

    International Nuclear Information System (INIS)

    We have modeled gyrotron windows and gyrotron amplifier sever structures for TE modes in the 100-150 GHz range and have computed the reflection and transmission characteristics from the field data. Good agreement with frequency domain codes and analytic analysis have been obtained for some simple geometries. We present results for realistic structures with lossy coatings and describe implementation of microwave diagnostics. (Author) 5 figs., 7 refs

  3. Progress of microwave collective Thomson scattering in LHD

    International Nuclear Information System (INIS)

    Microwave collective Thomson scattering (CTS) by using a 77 GHz gyrotron is routinely working in LHD and the improvements of the system is now underway. The targets of this diagnostic are measurements of energetic fast ion distribution and ion ratio. In the present system, 800kW 77 GHz gyrotron is injected horizontally and scattered radiation is received changing scattering angle. The system works with existence of electron cyclotron resonance layer. Thus, most of the power is absorbed at the layer like beam damping and stray radiation dramatically decreases. Gyrotron is modulated at 40 Hz, then, background ECE, which is signal in gyrotron off phase, is subtracted from scattered signal in gyrotron on phase. The perturbation of electron temperature due to the gyrotron injection is almost negligible. Temporal evolution of CTS spectrum is obtained by 32ch filter bank receiver through discharge and fine spectrum is obtained by 10 GHz sampling fast digitizer for 80 ms. Change of the width and asymmetry of CTS spectrum is observed after turning off of tangentially injected neutral beam (NB). This is qualitatively consistent with reduction of fast ion density. Preliminary data of ion ratio between hydrogen and helium are also obtained

  4. ECH Technology Development

    Energy Technology Data Exchange (ETDEWEB)

    Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-12-24

    Electron Cyclotron Heating (ECH) is needed for plasma heating, current drive, plasma stability control, and other applications in fusion energy sciences research. The program of fusion energy sciences supported by U. S. DOE, Office of Science, Fusion Energy Sciences relies on the development of ECH technology to meet the needs of several plasma devices working at the frontier of fusion energy sciences research. The largest operating ECH system in the world is at DIII-D, consisting of six 1 MW, 110 GHz gyrotrons capable of ten second pulsed operation, plus two newer gyrotrons. The ECH Technology Development research program investigated the options for upgrading the DIII-D 110 GHz ECH system. Options included extending present-day 1 MW technology to 1.3 – 1.5 MW power levels or developing an entirely new approach to achieve up to 2 MW of power per gyrotron. The research consisted of theoretical research and designs conducted by Communication and Power Industries of Palo Alto, CA working with MIT. Results of the study would be validated in a later phase by research on short pulse length gyrotrons at MIT and long pulse / cw gyrotrons in industry. This research follows a highly successful program of development that has led to the highly reliable, six megawatt ECH system at the DIII-D tokamak. Eventually, gyrotrons at the 1.5 megawatt to multi-megawatt power level will be needed for heating and current drive in large scale plasmas including ITER and DEMO.

  5. ECH on the MTX [Microwave Tokamak Experiment

    International Nuclear Information System (INIS)

    The Microwave Tokamak Experiment (MTX) at LLNL is investigating the heating of high density Tokamak plasmas using an intense pulse FEL. Our first experiments, now beginning, will study the absorption and plasma heating of single FEL pulses (20 ns pulse length and peak power up to 2 GW) at a frequency of 140 GHz. A later phase of experiments also at 140 GHz will study FEL heating at 5 kHz rate for a pulse train up to 50 pulses (35 ns pulse length and peak power up to 4 GW). Future operations are planned at 250 GHz with an average power of 2 MW for a pulse train of 0.5 s. The microwave output of the FEL is transported quasi-optically to the tokamak through a window-less, evacuated pipe of 20 in. diameter, using a six mirror system. Computational modelling of the non-linear absorption for the MTX geometry predicts single-pass absorption of 40% at a density and temperature of 1.8 /times/ 1020m/sup /minus/3/ and 1 keV, respectively. To measure plasma microwave absorption and backscatter, diagnostics are available to measure forward and reflected power (parallel wire grid beam-splitter and mirror directional couplers) and power transmitted through the plasma (segmented calorimeter and waveguide detector). Other fast diagnostics include ECE, Thompson scattering, soft x-rays, and fast magnetic probes. 8 refs., 2 figs

  6. ECH on the MTX

    International Nuclear Information System (INIS)

    The Microwave Tokamak Experiment (MTX) at LLNL is investigating the heating of high density Tokamak plasmas using an intense pulse FEL. Our first experiments, now beginning, will study the absorption and plasma heating of single FEL pulses (20 ns pulse length and peak power up to 2 GW) at a frequency of 140 GHz. A later phase of experiments also at 140 GHz (FY 90) will study FEL heating at 5 kHz rate for a pulse train up to 50 pulses (35 ns pulse length and peak power up to 4 GW). Future operations are planned at 250 GHz with an average power of 2 MW for a pulse train of 0.5 s. The microwave output of the FEL is transported quasi-optically to the tokamak through a window-less, evacuated pipe of 20 in diameter, using a six mirror system. Computational modelling of the non-linear absorption for the MTX geometry predicts single-pass absorption of 40% at a density and temperature of 1.8x1020 m-3 and 1 keV, respectively. To measure plasma microwave absorption and backscatter, diagnostics are available to measure forward and reflected power (parallel wire grid beam-splitter and mirror directional couplers) and power transmitted through the plasma (segmented calorimeter and waveguide detector). Other fast diagnostics include ECE, Thompson scattering, soft x-rays, and fast magnetic probes

  7. Floating data acquisition system for microwave calorimeter measurements on MTX

    International Nuclear Information System (INIS)

    A microwave calorimeter has been designed for making 140-GHz absorption measurements on the MTX. Measurement of the intensity and spatial distribution of the FEL-generated microwave beam on the inner wall will indicate the absorption characteristics of the plasma when heated with a 140 GHz FEL pulse. The calorimeter works by monitoring changes of temperature in silicon carbide tiles located on the inner wall of the tokamak. Thermistors are used to measure the temperature of each tile. The tiles are located inside the tokamak about 1 cm outside of the limiter radius at machine potential. The success of this measurement depends on our ability to float the data acquisition system near machine potential and isolate it from the rest of the vault ground system. Our data acquisition system has 48 channels of thermistor signal conditioning, a multiplexer and digitizer section, a serial data formatter, and a fiber-optic transmitter to send the data out. Additionally, we bring timing signals to the interface through optical fibers to tell it when to begin measurement, while maintaining isolation. The receiver is an HP 200 series computer with a serial data interface; the computer provides storage and local display for the shot temperature profile. Additionally, the computer provides temporary storage of the data until it can be passed to a shared resource management system for archiving. 2 refs., 6 figs

  8. Stellarator News, Issue 38, March 1995

    CERN Document Server

    Rome, J A

    1995-01-01

    Stellarator News, an international journal of the stellarator community, is Published by Fusion Energy Division, Oak Ridge National Laboratory, James A. Rome, Editor In the March 1995 issue . . . **** Exerpts from the U.S. Congress Office of Technology Assment report on TPX and Alternate Concepts. **** Edge transport and turbulence studies on U-3M The turbulent-driven particle flow is shown to be comparable with the equilibrium flow at the boundary of the configuration under Alfven-heating conditions in the U-3M torsatron. **** Topological aspects of island divertor studies on W7-AS The structure of the edge plasma in W7-AS, observed with probes, television camera, and H-alpha light agrees at low beta with vacuum field calculations: the low-valued resonances at iotabar=5/m are resolved for m = 8 to 11; external perturbations are not significant at the edge, even for iotabar = 5/10. **** 140-GHz second harmonic O-mode electron cyclotron heating at W7-AS First experimental results are presented of 140-GHz secon...

  9. The ECRH system for JET-EP

    International Nuclear Information System (INIS)

    An ECW (electron cyclotron wave) system is being designed for JET. The system will consist of 6 gyrotrons, 1 MW each, in order to deliver 5 MW into the plasma. An extension of 2 more gyrotrons is recently being considered. The system will especially be designed to enable the control of neo-classical tearing modes (NTM). Furthermore, heating and current drive is foreseen in a large number of different target plasma configurations and the control of the ratio of the electron and ion temperatures. The frequency, 113.3 GHz, is selected to enable a wide range of operating toroidal magnetic fields from 3 to 4 T and at second harmonic at lower fields and also to allow for a future upgrade to 170 GHz using the same systems, including the double-disk diamond windows. The main elements of the ECW system are: gyrotrons with a depressed collector, 1 MW each, 10 s pulse duration with a diamond window, with Gaussian output mode; main power supplies, up to 60 kV, with a solid-state crowbar to feed two gyrotrons. A series IGBT switch will enable independent control of each gyrotron; evacuated waveguides or quasi-optical mirror lines will be each capable of transmitting 1 MW, having a double-disk diamond window located near the torus as an additional tritium barrier. The total length is in the order of 80 to 100m; a plug-in launcher, steerable in both toroidal and poloidal angle. A trade-off will be made between a single launching mirror per transmission line or two beams per launching mirror in order to have the highest flexibility, but also the narrowest beam size in the plasma. The gyrotron power supplies. The configuration of the collector power supply is based on the connection of two gyrotrons to one existing (former lower hybrid) 60 kV power supply. To limit the energy deposit into an internal arc, IGBT switches are connected in series with the gyrotrons, to disconnect the gyrotron from the power supply within 2 μs. An LR snubber is connected in series with the gyrotrons to

  10. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  11. Determination of electromagnetic modes in oversized corrugated waveguides on the electron cyclotron resonance heating installation at the tokamak Tore Supra; Determination de modes electromagnetiques de guides d'ondes corrugues surdimensionnes sur l'installation de chauffage des electrons de tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Courtois, L

    2001-03-09

    Electron cyclotron resonance heating (ECRH) in the Tore Supra tokamak constitutes an important step in the research aimed at obtaining thermonuclear fusion reactions. Electron heating is achieved by transmitting an electromagnetic wave from the oscillators (gyrotrons) to the plasma via the fundamental mode, propagating in oversized corrugated waveguides. Maximizing the proportion of the gyrotron power coupled to the fundamental waveguide mode is essential for the good functioning of the transmission line and for maximizing the effect on the plasma. This thesis gives all necessary tools for finding the proportion of the fundamental mode and all other modes present in passive components and at the output of the gyrotron as installed in the Tore Supra ECRH plant. This characterisation is based on obtaining amplitude and phase diagrams of the electric field on a plane transverse to the propagation axis. The most difficult part of obtaining these diagrams is measuring the phase which, despite the very short wavelength, is measured directly at low power levels. At high power levels the phase is numerically reconstructed from amplitude measurements for gyrotron characterisation. A complete theoretical study of the phase reconstruction code is given including its validation with theoretical diagrams. This study allows the realisation of a modal characterisation unit electromagnetic for measurement of radiated beams and usable in each part of the ECRH installation. At the end, the complete modal characterisation is given at low level for a mode converter and also at high level for the first series gyrotron installed at TORE SUPRA. (author)

  12. Upgrades for the ECH System on DIII-D

    Science.gov (United States)

    Lohr, J.; Cengher, M.; Doane, J. L.; Gorelov, Y. A.; Moeller, C. P.; Ponce, D.; Noraky, S.; Penaflor, B. G.; Kolemen, E.

    2012-10-01

    The gyrotron system for electron cyclotron heating on the DIII-D tokamak is being upgraded with the addition of higher efficiency gyrotrons having collector potential depression. Two new gyrotrons, operating at the present frequency of 110 GHz and generating 1.2 MW per unit, have been manufactured and are being installed and tested. The subsequent group of gyrotrons have been designed to generate 1.5 MW for 10 s pulses at 117.5 GHz. The first of these tubes is presently being manufactured at Communications and Power Industries. By the end of 2013, the system will comprise eight high power gyrotrons and, pending the successful performance of the 1.5 MW tube, an upgrade to a 15 MW system will begin. High voltage power supplies, transmission lines, launchers and associated control and data acquisition systems are included in the upgrades as is enhanced ability to steer the rf beams under a variety of pre-programed and reactive scenarios.

  13. Initial results for a 170 GHz high power ITER waveguide component test stand

    Science.gov (United States)

    Bigelow, Timothy; Barker, Alan; Dukes, Carl; Killough, Stephen; Kaufman, Michael; White, John; Bell, Gary; Hanson, Greg; Rasmussen, Dave

    2014-10-01

    A high power microwave test stand is being setup at ORNL to enable prototype testing of 170 GHz cw waveguide components being developed for the ITER ECH system. The ITER ECH system will utilize 63.5 mm diameter evacuated corrugated waveguide and will have 24 >150 m long runs. A 170 GHz 1 MW class gyrotron is being developed by Communications and Power Industries and is nearing completion. A HVDC power supply, water-cooling and control system has been partially tested in preparation for arrival of the gyrotron. The power supply and water-cooling system are being designed to operate for >3600 second pulses to simulate the operating conditions planned for the ITER ECH system. The gyrotron Gaussian beam output has a single mirror for focusing into a 63.5 mm corrugated waveguide in the vertical plane. The output beam and mirror are enclosed in an evacuated duct with absorber for stray radiation. Beam alignment with the waveguide is a critical task so a combination of mirror tilt adjustments and a bellows for offsets will be provided. Analysis of thermal patterns on thin witness plates will provide gyrotron mode purity and waveguide coupling efficiency data. Pre-prototype waveguide components and two dummy loads are available for initial operational testing of the gyrotron. ORNL is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under Contract DE-AC-05-00OR22725.

  14. Remote Control System of the TJ-II Microwave Transmission Lines Mirrors

    International Nuclear Information System (INIS)

    The ECRH system of the TJ-II stellarator has two gyrotrons, which deliver a maximum power of 300 kW each at a frequency of 53.2 GHz. Another 28 GHz gyrotron will be used to heat the plasma by electron Bernstein waves (EBWH). The microwave power is transmitted from the gyrotrons to the vacuum chamber by two quasi-optical transmission lines for ECRH and a corrugated waveguide for EBWH. All transmission lines have an internal movable mirror inside the vacuum chamber to focus the beam and to be able to change the launching angle. The control of the beam polarization is very important and the lines have two corrugated mirrors, which actuate as polarizers. In this report the control system of the position of these three internal mirrors and the polarizers of the EBWH transmission line is described. (Author) 20 refs

  15. Fundamental mode rectangular waveguide system for electron-cyclotron resonant heating (ECRH) for tandem mirror experiment-upgrade (TMX-U)

    International Nuclear Information System (INIS)

    We present a brief history of TMX-U's electron cyclotron resonant heating (ECRH) progress. We emphasize the 2-year performance of the system, which is composed of four 200-kW pulsed gyrotrons operated at 28 GHz. This system uses WR42 waveguide inside the vacuum vessel, and includes barrier windows, twists, elbows, and antennas, as well as custom-formed waveguides. Outside the TMX-U vessel are directional couplers, detectors, elbows, and waveguide bends in WR42 rectangular waveguide. An arc detector, mode filter, eight-arm mode converter, and water load in the 2.5-in. circular waveguide are attached directly to the gyrotron. Other specific areas discussed include the operational performance of the TMX-U pulsed gyrotrons, windows and component arcing, alignment, mode generation, and extreme temperature variations. Solutions for a number of these problems are described

  16. Remote Control System of the TJ-II Microwave Transmission Lines Mirrors; Sistema de Control Remoto de los Espejos de las Lineas de Transmision de Microondas del TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Sanchez, A.; Fernandez, A.; Cappa, A.; Gama, J. de la; Olivares, J.; Garcia, R.; Chamorro, M.

    2007-09-27

    The ECRH system of the TJ-II stellarator has two gyrotrons, which deliver a maximum power of 300 kW each at a frequency of 53.2 GHz. Another 28 GHz gyrotron will be used to heat the plasma by electron Bernstein waves (EBWH). The microwave power is transmitted from the gyrotrons to the vacuum chamber by two quasi-optical transmission lines for ECRH and a corrugated waveguide for EBWH. All transmission lines have an internal movable mirror inside the vacuum chamber to focus the beam and to be able to change the launching angle. The control of the beam polarization is very important and the lines have two corrugated mirrors, which actuate as polarizers. In this report the control system of the position of these three internal mirrors and the polarizers of the EBWH transmission line is described. (Author) 20 refs.

  17. 3.6MW Power Supply System of the 170GHz ECH&CD System in KSTAR

    Science.gov (United States)

    Shim, Eun-yong; Ahn, Il-kun; Seo, Tae-won; Lee, Seung-kyo; Bae, Young-soon; Joung, Jin-Hyun; Joung, Mi

    2012-09-01

    A 3.6 MW (-66 kV/55 A) Gyrotron power supply system was developed for the 170 GHz ECH&CD gyrotron system in KSTAR. This power supply system consists of Cathode Power Supply(CPS), Anode Power Supply(APS) and Body Power Supply(BPS). The CPS is using the Pulse Step Modulation by the 32set of IGBT choppers. The respons time of Chopper is very fast. So the cathode voltaget is able to be controlled rapidly. The APS is a sort of voltage devider using zener and switch component. It was achieved 3kHz modulation operation. The BPS is combined the commercial power supply and special high voltage switches. It is very simple topology but 5kHz modulation was accomplished easily. Theses power supply system were installed and commissioned successfully in 2011. This paper presents the topology of the each power supply and test result for 170 GHz gyrotron in KSTAR.

  18. Design of plasmonic photodetector with high absorptance and nano-scale active regions.

    Science.gov (United States)

    Guo, Jingshu; Wu, Zhiwei; Li, Yuan; Zhao, Yanli

    2016-08-01

    We propose a novel plasmonic photodetector with high responsivity, utilizing nano-scale active regions. This design can be applied to diverse materials (group III-V or IV materials) and different operation wavelengths covering the O-U bands. The periodic structure utilizing Surface Plasmon Polariton Bloch Waves (SPP-BWs) has low optical power loss. FDTD simulation shows an absorptance of 74.4% which means a responsivity of about 0.74 A/W at 1550 nm. The low capacitance brings low noise, reduced power consumption, and a high electrical bandwidth which is estimated to be 140 GHz. Among the plasmonic PDs with inherent high speeds but low responsivities, our design makes the obvious progress on improving the absorptance. PMID:27505787

  19. Antenna system analysis and design for automatic detection and real-time tracking of electron Bernstein waves in FTU

    Science.gov (United States)

    Bin, W.; Alessi, E.; Bruschi, A.; D'Arcangelo, O.; Figini, L.; Galperti, C.; Garavaglia, S.; Granucci, G.; Moro, A.

    2014-05-01

    The algorithm for the automatic control of the new front steering antenna of the Frascati Tokamak Upgrade device has been improved, in view of forthcoming experiments aimed at testing the mode conversion of electron cyclotron waves at a frequency of 140 GHz. The existing antenna system has been prepared to provide two-point real-time measurements of electron Bernstein waves and to allow real-time tracking of the optimal conversion region. This required an accurate analysis of the antenna to minimize the risk of a mechanical damage of the movable launching mirrors, when accessing the high toroidal launching angles needed for this kind of experiment. A detailed description is presented of the work carried out to safely reach and validate the desired range of steering angles, which include the region of interest, and a technique is proposed to track and chase the correct line of sight for electron Bernstein waves detection during the shot.

  20. Evaluation of cross-connected waveguides as transfer standards of transmission at high millimetre-wave frequencies

    Science.gov (United States)

    Ridler, Nick; Clarke, Roland; Huang, Hui; Zinal, Sherko

    2016-08-01

    At the present time, transfer and verification standards of transmission coefficient (or, equivalently, transmission loss) are not readily available at high millimetre-wave frequencies (i.e. at frequencies ranging typically from 100 GHz to 300 GHz). In recent years, cross-connected waveguide devices have been proposed to provide calculable standards of transmission loss at these frequencies. This paper investigates the viability of these cross-connected waveguides as transfer standards of transmission for inter-laboratory measurement comparison exercises. This relates to their potential use in activities such as international key comparison exercises and measurement audit programmes. A trial inter-laboratory comparison involving four laboratories using two cross-connected waveguides in the WR-05 waveguide size (covering frequencies from 140 GHz to 220 GHz) is described and includes an analysis of the measurement results obtained during the comparison exercise.

  1. High-frequency resonant tunnelling diode oscillator with high-output power

    Science.gov (United States)

    Wang, Jue; Alharbi, Khalid; Ofiare, Afesomeh; Khalid, Ata; Cumming, David; Wasige, Edward

    2015-10-01

    In this paper, a prototype G-band (140 GHz-220 GHz) monolithic microwave integrated circuit (MMIC) resonant tunneling diode (RTD) oscillator is reported. The oscillator employs two In0.53Ga0.47As/AlAs RTD devices in the circuit to increase the output power. The measured output power was about 0.34 mW (-4.7 dBm) at 165.7 GHz, which is the highest power reported for RTD oscillator in G-band frequency range. This result demonstrates the validity of the high frequency/high power RTD oscillator design. It indicates that RTD devices, as one of the terahertz (THz) source candidates, have promising future for room-temperature THz applications in such as imaging, wireless communication and spectroscopy analysis, etc. By optimizing RTD oscillator design, it is expected that considerably higher power (>1 mW) at THz frequencies (>300 GHz) will be obtained.

  2. Microwave interferometer using 94-GHz solid-state sources

    International Nuclear Information System (INIS)

    A 94-GHz microwave interferometer has been designed for the Tandem Mirror Experiment Upgrade and the Mirror Fusion Test Facility to replace the 140-GHz system. The new system is smaller and has modular single-channel units designed for high reliability. It is magnetically shielded and can be mounted close to the machine, which allows the use of lower power solid-state sources. Test results of the 94-GHz prototype indicate that the phase resolution is better than 10, the Impatt FM noise is 5 MHz wide, and the Gunn FM noise is 6 kHz wide. This paper presents the antenna designs along with the test results and discusses the unique problems associated with diagnosing a high electron temperature plasma in the presence of electron cyclotron resonant heating

  3. Dual-Array Electron Cyclotron Emission Imaging (ECEI): a New Millimeter Wave Imaging System for Electron Temperature Fluctuation on the DIII-D Tokamak

    Science.gov (United States)

    Luhmann, N. C., Jr.; Tobias, B. J.; Domier, C. W.; Kong, X.; Liang, T.; Jaspers, R.; Donne, A. J. H.; Smith, M.; Nazikian, R.; Park, H. K.

    2009-11-01

    A new diagnostic tool has been developed for simultaneous real-time imaging of electron temperature fluctuations at both the high and low field sides. Separate imaging arrays spanning 75 to 110 and 90 to 140 GHz, respectively consist of 160 channels (20 vertical by 8 radial) with ˜1 cm^2 resolution, providing up to 55 cm of vertical plasma coverage. Fluctuations of 1% are measurable on μs time-scales. The technical capabilities of this diagnostic, as well as potential physics issues to be investigated, are discussed. The details of the constituent technologies, including advanced antennas and substrate lenses, quasi-optical planar filter components, and double down-conversion heterodyne signal detection will be addressed.

  4. Conceptual design of an electron cyclotron wave system for NET/ITER

    International Nuclear Information System (INIS)

    Electron Cyclotron waves (ECWs) provide a scheme for electron heating, which, owing to the strong localization of the resonant interaction with the plasma, allows an efficient tailoring of the power deposition profile. In the proposed ITER reference scenario for current drive and heating, ECWs are considered to assist plasma formation, pre-heating, local current profile control near the q=2 surface and possibly for baking the first wall tiles. For these functions, a total power of 20 MW, CW, at a frequency around 120 GHz is needed. A higher frequency system (140 GHz, 20 MW, CW), is also considered to heat the plasma centre and provide burn control. The same system at increased power could be used for plasma heating to ignition. For NET, due to the higher magnetic field, the frequencies needed for the tasks mentioned above are approximately 140 GHz and 160 GHz, respectively. ECWs are also envisaged for bulk heating of the NET plasma. Here, frequencies of about 160 GHz are necessary. A detailed study for the 120 GHz/20 MW ITER reference system has been performed. Scaling rules as well as additional antenna designs for higher frequency systems have been developed. The design principle was to offer a high degree of flexibility for the wide range of envisaged uses of the ECWs. The ECW system should satisfy the physics requirements, advanced requirements of reliability and availability, and must be compatible with the nuclear environment (which requires radiation resistance as well as remote maintenance of at least the antenna part). Therefore, it has been tried to place the most critical components as far away from the machine as possible. To improve the availability, the installation of 15% spare tubes and transmission systems is proposed. (orig.)

  5. 300 GHz ジャイロトロンを用いた材料処理装置の開発

    OpenAIRE

    佐古, 勝英; 谷, 晋仁; 橋本, 秀一; 尾関, 隆則; 光藤, 誠太郎; 立松, 芳典; 斉藤, 輝雄; 出原, 敏孝; SAKO, Katsuhide; TANI, Shinji; HASHIMOTO, Syuiti; Ozeki, Takanori; MITSUDO, Seitaro; TATEMATSU, Yoshinori; SAITO, Teruo

    2010-01-01

    The effective characteristics of high frequency and strong electric field processing wereobserved. One of the interesting effects is the so-called non-thermal effect or microwave effect. In order to widely study the non-thermal effect of ceramics sintering and application of material processing, we developed a material processing system by using the 300 GHz gyrotron FU CW I. This system consists of a 300GHz, 2.3 kW, CW gyrotron with a cryogen free 12 T superconducting magnet, a corrugated cir...

  6. Recent progresses in the 110 GHz ECRF system on JT-60U tokamak

    International Nuclear Information System (INIS)

    The 110 GHz ECRF system on the JT-60U started its operation with a 1 MW gyrotron in 1999. Two additional units were completed in 2000. The forth unit was available to generate the total power of 4 MW in 2001. The 1 MW gyrotron is featured by a collector potential depression structure and a diamond output window. The system has four evacuated waveguide lines in 50-60 m length with nine miter bends, each of which has a diamond window near the antenna. One of the recent progresses in this system is to up-grade the gyrotron, whose previous performance was limited to less than 1 MW x 2 sec by a parasitic oscillation in it. Three of four gyrotrons were improved for suppression of the parasitic oscillation by installing a RF absorber in the beam tunnel. The second progress is to reduce the fluctuation in the acceleration voltage for the high power gyrotron operation. The main DC voltage power supply for the gyrotron is not regulated in the system. Before this progress, a large fluctuation in the DC voltage disturbed the stable gyrotron oscillation when four gyrotrons were simultaneously in operation. The third progress is to improve the transmission efficiency from 60-75% to 70-80% by re-adjusting the alignment of the waveguide lines. By these progresses, a generated power on the best unit has reached up to ∼ 1.2 MW x 4.1 s (∼ 1 MW x 5 s) corresponding to ∼ 1 MW (∼ 0.8 MW) for the injected power into plasmas. The total injected power has been 3 MW x 2 sec (∼ 2.8 MW x 3.6 s) using four units. A local profile control has been performed using two steerable antennas at this power level during a plasma discharge. The test of the feedback control of the steerable antenna linked with the perturbation of electron temperature has been successfully done for stabilization the MHD instability such as NTM. (authors)

  7. High power test of a wideband diplexer with short-slotted metal half mirrors for electron cyclotron current drive system

    International Nuclear Information System (INIS)

    The wideband high power diplexer has been developed for combining and fast switching of high power millimeter waves generated by a dual frequency gyrotron. The actual diplexer was tested at the frequency band of 170 GHz in low power. After adjusting a resonant frequency of diplexer for the gyrotron frequency, the evacuated wideband diplexer with short-slotted metal half mirrors was tested at an incident power of about 150 kW, a pulse duration of 30 ms and a frequency band of 170.2–170.3 GHz. Any discharge damage was not observed in the diplexer

  8. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang;

    2008-01-01

    The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110...... of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment...

  9. Water‐Data Report 411214091070601 LAKE ODESSA AT SCHAFER LANDING NR WAPELLO IOWA 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Water levels and water quality parameters recorded on Crane Creek. LOCATION: Lat. 41° 12 '14" W Long. 91° 7' 6" near Wapello, Iowa. Wapello County. Schafer Landing...

  10. Fusion development and technology

    International Nuclear Information System (INIS)

    This report discusses the following topics: superconducting magnet technology high field superconductors; advanced magnetic system and divertor development; poloidal field coils; gyrotron development; commercial reactor studies -- Aries; ITER physics; ITER superconducting PF scenario and magnet analysis; and safety, environmental and economic factors in fusion development

  11. Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Bindslev, Henrik;

    2008-01-01

    Collective Thomson scattering (CTS) has the capabilities to measure phase space densities of fast ion populations in ITER resolved in configuration space, in velocity space, and in time. In the CTS system proposed for ITER, probing radiation at 60 GHz generated by two 1 MW gyrotrons is scattered...

  12. 1990's annual report of INPE's Plasma Associated Laboratory

    International Nuclear Information System (INIS)

    This is the 1990's annual report of INPE's Plasma Associated Laboratory it contains information on current research developed at the laboratory including quiescent plasma, magnetized plasma, plasma centrifuge, plasma and radiation (gyrotron), ionic propulsion, and toroidal plasma. (A.C.A.S.)

  13. System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, Malcolm; Friedman, Herbert W.

    2005-07-19

    A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

  14. EC power sources: European technological developments towards ITER

    International Nuclear Information System (INIS)

    The activities in Europe towards the development of the EC power sources for ITER are centered on the development of a 170 GHz, 2 MW, CW coaxial cavity gyrotron of collector potential depressed (CPD) type. A gyrotron with a higher unit power than the ITER reference (1 MW) would yield a reduction of the installation costs, a more compact launcher design and, if required, an increase of the power delivered through one port. Tests proving the principle were successfully performed on a short-pulse experimental gyrotron delivering up to 2.2 MW in single mode. Following this success, a coordinated and fully consistent programme of development has been launched. The first industrial 2 MW prototype is now at an advanced stage of construction. The associated superconductive magnet producing 6.86 T on the cavity axis is also being procured. Dummy loads suitable for short and CW operation are also part of the development effort. Finally, a new EC test facility, with the features necessary for the testing of the gyrotron up to full power in CW, has been established and includes a fully solid-state power supply system

  15. PERFORMANCE OF THE DIII-D SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    CALLIS,RW; KAJIWARA,K; LOHR,J; GORELOV,YA; PONCE,D

    2003-08-01

    A271 PERFORMANCE OF THE DIII-D SYSTEM. Three 110 GHz gyrotrons with nominal output power of 1 MW each have been installed and are operational on the DIII-D tokamak. All three gyrotrons were built by Communications and Power Industries (CPI). The CPI gyrotrons utilize a single disc CVD (chemical-vapor-deposition) diamond window that employs water cooling around the edge of the disc. Calculations predict that the CVD diamond window should be capable of full 1 MW cw operation, which is supported by IR camera measurements that show the window reaching equilibrium after 2.5 s. All gyrotrons are connected to the tokamak by low-loss-windowless evacuated transmission line using circular corrugated waveguide for propagation in the HE{sub 11} mode. Each waveguide system incorporates a two-mirror launcher, which can steer the rf beam poloidally from the center to the outer edge of the plasma. Results obtained using the DIII-D ECH systems will be reported.

  16. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.;

    2014-01-01

    cyclotron heating beam. To clarify the diagnostic applicability of the gyrotron in the 77 GHz frequency band, we investigated the dependence of the probe and receiver beam trajectories in plasmas with high electron densities of (4–5) × 1019 m−3 and low electron densities of (1–2) × 1019 m−3. At high density...

  17. Elmo Bumpy Torus proof of principle, Phase II: Title 1 report. Volume IV. Microwave system. Preliminary design report

    International Nuclear Information System (INIS)

    The EBT-P Microwave System provides microwaves for electron cyclotron resonance heating (ECRH) to both stabilize and heat the EBT-P plasma. A 28 gigahertz (GHz) system is required to form the hot electron annulus plasma that provides MHD stabilization to the core plasma. A 60 GHz system is required to heat the core plasma and will provide some second harmonic heating of the hot electron annulus. The principal microwave system elements and their design characteristics are summarized. The microwave system includes 200 kilowatt (kW) gyrotrons at 60 GHz for core heating and 200 kW gyrotrons at 28 GHz for annulus heating. The basic operating complement will be six (6) 60 GHz tubes and two (2) 28 GHz tubes. PACE (Plant and Capital Equipment) procurement will include four (4) 60 GHz gyrotrons with two (2) GHz tubes procured under operations and the two (2) 28 GHz tubes will be provided, with mounts, from the EBT-S program. Each tube is rigidly mounted on an oil filled tank assembly which provides electrical isolation and cooling. All tubes and mounts will be located in the lower level of the torus enclosure. An extensive demineralized water flow system is required to provide gyrotron cooling

  18. Fast ion millimeter wave collective Thomson scattering diagnostics on TEXTOR and ASDEX upgrades

    DEFF Research Database (Denmark)

    Michelsen, S.; Korsholm, Søren Bang; Bindslev, H.;

    2004-01-01

    Collective Thomson scattering (CTS) diagnostic systems for measuring fast ions in TEXTOR and ASDEX Upgrade are described in this article. Both systems use millimeter waves generated by gyrotrons as probing radiation and the scattered radiation is detected with heterodyne receivers having 40...

  19. Contributions to resolving issues impeding the operation of high power microwave devices

    Science.gov (United States)

    Kashyn, Dmytro

    This thesis reports an experimental study aimed at extending high power, high efficiency gyrotron operation to submillimeter wavelengths. A series of experiments carried out both at the University of Maryland and the Institute of Applied Physics of the Russian Academy of Science, succeeded in demonstrating output power at 670 GHz of 180 kilowatts with 20% efficiency (gyrotron voltage was 57 kV and beam current was 16 amperes). The maximum output power achieved in the experiments was 210kW at somewhat higher voltage and current (viz. 58kV and 22A). The achieved output power and efficiency are twice as large as achieved in previous experiments in this frequency range with pulse duration in the range of tens of microseconds. These performance parameters are relevant to a previously proposed application of detecting concealed radioactive materials by air breakdown in a focused beam of sub-millimeter radiation. The 670 GHz gyrotron combined features of two lines of previous experiments: (a) to operate at the required frequency, pulsed solenoids producing 28T magnetic were employed and (b) to obtain high efficiency a very high order mode was used in the gyrotron cavity, as in the experiments with gyrotrons for plasma heating. Evidence of multimode beating was observed in submillimeter output envelope. The excitation of spurious modes, especially during the rise of the gyrotron voltage pulse, was analyzed and the method of avoiding this was proposed which also allows to reduce collector loading in gyrotrons operating in modulated regimes. The present study also includes theoretical analysis of the processes that deepens the understanding of microwave breakdown (arcing) in high power microwave devices. The effect of the dust particles microprotrusions on the device operation was analyzed. These microprotrusions were observed and their negative effects were remedied by careful polishing and machining of the resonator surface. Finally, the generated 670 GHz radiation was

  20. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

    Directory of Open Access Journals (Sweden)

    Wagner D.

    2015-01-01

    Full Text Available Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength. A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B, ABmm (MVNA 8-350 and Rohde&Schwarz (ZVA24 together with frequency multipliers. The

  1. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

    Science.gov (United States)

    Wagner, D.; Bongers, W.; Kasparek, W.; Leuterer, F.; Monaco, F.; Münich, M.; Schütz, H.; Stober, J.; Thumm, M.; Brand, H. v. d.

    2015-03-01

    Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap) may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength). A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix) simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B), ABmm (MVNA 8-350) and Rohde&Schwarz (ZVA24) together with frequency multipliers. The stop bands

  2. Research and Development of 2-frequency (110/138 GHz FADIS for JT-60SA ECHCD system

    Directory of Open Access Journals (Sweden)

    Idei H.

    2015-01-01

    Full Text Available A FAst DIrectional Switch (FADIS of 2-frequency (2-ƒ gyrotron system for the JT-60SA project is being developed under collaboration between Japan Atomic Energy Agency (JAEA and Kyushu University. At first, the frequency drift and dip in the gyrotron operation were measured to consider which kind of FADIS is preferred for application in the Electron Cyclotron Heating and Current Drive (ECHCD system for the JT- 60SA. Various types of the FADIS have been considered. A square corrugated waveguide diplexer system with double resonant rings was considered as one of the most attractive FADIS systems for stable high-power and long-pulse operations in the 2-ƒ JT-60SA ECHCD system.

  3. Final report for the tunable driver for the LLNL FEL experiment

    International Nuclear Information System (INIS)

    This section of the report covers the recent operation of the prototype backward-wave oscillator (BWO) gyrotron. The tube was mounted in its fixture on the superconducting magnet, the beam aligned, and microwaves generated. Initial alignment and operation was performed at low wiggler magnet strength (Bw = 9 G) and thus low α = υ perpendicular/υ parallel. The microwaves observed under these conditions were at a frequency just above the electron cyclotron frequency of the interaction region. Identification of these waves is tentatively that of forward waves generated in what is a very long gyrotron cavity. By increasing the wiggler field to ∼ 18 G, the backward wave could then be observed. Voltage tunability of the backward wave was demonstrated and frequencies from 13 GHz to 143 GHz were observed

  4. Initial operation of ECRH heating experiments on the Versator II tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Luckhardt, S.C.; Chen, K.I.; Kirkwood, R.; Porkolab, M.; Singleton, D.; Squire, J.; Villasenor, J.; Lu, Z.

    1987-09-01

    Operation of a 35GHz electron cyclotron heating experiment has begun on Versator II with gyrotron power of 100kW. The EC antenna is located on the high magnetic field side of the plasma and launches linearly polarized radiation in the HE11 hybrid mode with externally controllable polarization and parallel index of refraction. The transmission system provides mode conversion from the TE01 output mode of the gyrotron to the HE11 mode and polarization control. The mode transformation characteristics of the transmission system were measured by means of a computer controlled two dimensional scanning system, and contour plots of the far field radiation pattern of each transmission system element were made and compared with theory. Overall the transmission system is found to be approximately 95% efficient with mode patterns in generally excellent agreement with theory.

  5. Experimental study on resonance relativistic SHF generators on the base of linear induction electron accelerator

    International Nuclear Information System (INIS)

    The results of studies on relativistic SHF-generators - orotron and gyrotron for obtaining data on the quality of a high-current electron beam shaped in the section of a linear induction accelerator are given. Axisymmetric resonators as sections of weak-irregular waveguides were used in both generators. Stable generation of short-wave radiation of 15-20 MW at the efficiency of 5-7% SHF pulse duration of 50 ns was obtained in the orotron at the wave length of 8.5 mm and current of 600 A. Stable generation of 7-10 MW SHF-radiation at the efficiency of 3-5% and pulse duration of 150 ns was observed in the gyrotron at the wave length of 12 mm. Under further acceleration in the following sections of the accelerator the electron beam may be used for obtaining radiation of shorter waves

  6. Infrared and millimeter waves. Volume 13 - Millimeter components and techniques. Part 4

    Science.gov (United States)

    Button, K. J.

    Recent experimentation and theoretical modeling of IR and millimeter-wave devices for various applications are discussed in depth. Attention is given to powerful gyrotrons for thermonuclear research, new, high power coherent, millimeter radiation sources, and a kinetic theory of a harmonic gyrotron oscillator with a slotted resonant structure. Communication, radar and radiometer applications of integrated fin-line components are discussed, and investigations into propagation and mode coupling phenomena in corrugated and smooth-wall circular waveguides are reviewed. The known far-infrared (FIR) properties of inhomogeneous materials are described, including experimentation with normal-metal and insulator composites and with superconductivity. Finally, recent experimental and theoretical work on solid-state spectroscopy with FIR continuous-wave lasers is summarized in comparison with the performance bounds of Fourier spectroscopy.

  7. Injection locking of an electronic maser in the hard excitation mode

    Energy Technology Data Exchange (ETDEWEB)

    Yakunina, K. A. [Saratov State University, 83 Astrakhanskaya St., 410012 Saratov (Russian Federation); Kuznetsov, A. P.; Ryskin, N. M. [Saratov State University, 83 Astrakhanskaya St., 410012 Saratov (Russian Federation); Department of Nonlinear Physics, Saratov Branch, V.A. Kotel' nikov Institute of Radio Engineering and Electronics, 38 Zelenaya St., 410019 Saratov (Russian Federation)

    2015-11-15

    The phenomenon of hard excitation is natural for many electronic oscillators. In particular, in a gyrotron, a maximal efficiency is often attained in the hard excitation regime. In this paper, we study the injection-locking phenomena using two models of an electronic maser in the hard excitation mode. First, bifurcation analysis is performed for the quasilinear model described by ordinary differential equations for the slow amplitude and phase. Two main scenarios of transition to the injection-locked mode are described, which are generalizations of the well-known phase-locking and suppression mechanisms. The results obtained for the quasilinear model are confirmed by numerical simulations of a gyrotron with fixed Gaussian structure of the RF field.

  8. Development of a Propagating Millimeter-Wave Beam Position and Profile Monitor in the Oversize Corrugated Waveguide Used in an ECRH System

    Science.gov (United States)

    Shimozuma, Takashi; Kobayashi, Sakuji; Ito, Satoshi; Ito, Yasuhiko; Kubo, Shin; Yoshimura, Yasuo; Nishiura, Masaki; Igami, Hiroe; Takahashi, Hiromi; Mizuno, Yoshinori; Okada, Kohta; Mutoh, Takashi

    2016-01-01

    In a high-power electron cyclotron resonance heating (ECRH) system for plasma heating, a long-distance and low-loss transmission system of the millimeter wave is required. A real-time monitor of the millimeter-wave beam position and its intensity profile, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam-position and profile monitor (BPM) consists of a reflector, Peltier-device array, and a heat-sink, which is installed in the reflector-plate of a miterbend. The BPM was tested using both simulated electric heater power and high-power gyrotron output power. The profile obtained from the monitor using the gyrotron output was well agreed with the burn patter on a thermal sensitive paper. Methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated waveguide are proposed.

  9. High-Power Microwave Transmission and Mode Conversion Program

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, Ronald J. [Univ. of Wisconsin, Madison, WI (United States)

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  10. Synthesis method for using in the design of an electron gun for gyrotion

    International Nuclear Information System (INIS)

    In this work a synthesis method is applied to the design of an electron gun for a 94GHz gyrotron. Using the synthesis method, it is found the shape of the electrodes compatible with the laminar flow which minimizes the action of space change on the electron velocity dispersion. A sistematic procedure is presented to fuid the parameters of the synthesis method which, in turn, are closely related to the characteristics of the aptoclechonic system. (author)

  11. Initial results of electron cyclotron range of frequency (ECRF) operation and experiments in JT-60U

    International Nuclear Information System (INIS)

    The 110 GHz 1 MW electron cyclotron range of frequency (ECRF) system was designed and constructed on JT-60U to locally heat and control the plasmas. The gyrotron has a diamond window to transmit RF power with Gaussian mode, which is easily transformed to HE11 mode for the transmission line of the corrugated waveguide. The second diamond window is installed at the inlet of the antenna for a vacuum seal between the transmission line and the JT-60U tokamak. The total length of the transmission line from the gyrotron to the antenna is about 60 m including nine meter bends, The antenna has a focusing mirror and a flat steerable one to focus and to control the RF beam angle mainly in the poloidal direction. In the initial operation, the power of PEC∼0.75 MW for 2 s was successfully injected into plasma when the gyrotron generated the power up to 1 MW. The total transmission efficiency from the gyrotron to the plasma was about 75%. A controllability of local electron heating with the deposition width of =15 cm was well demonstrated by using the steerable mirror. A large downshift in the deposition position was observed at the high Te plasma. Strong central electron heating was obtained from 2.2 to 6.6 keV for PEC∼0.75 MW, 0.3 s at the optimized polarization. An effective electron heating was also obtained up to ∼10 keV during EC injection for ∼1.6 s in the high βp H-mode plasma produced by NBI

  12. Characteristics of a Teflon rod antenna for millimeter and submillimeter wave irradiation on living bodies

    OpenAIRE

    TATSUKAWA, Toshiaki; Doi, Akitaka; TERANAKA, Masato; Takashima, Hitoshi; Goda, Fuminori; Idehara, Toshitaka; Ogawa, Isamu; KANEMAKI, Tomohiro; NISHIZAWA, Seiji; NAMBA, Tunetoyo

    2003-01-01

    The development of a millimeter and submillimeter wave catheter for irradiation on living bodies using a Teflon rod dielectric antenna is described. The power sources of electromagnetic wave are an Impatt oscillator (90 GHz, 0.3 W) and gyrotron (302 GHz, 30 W). Irradiation tests using various Teflon rod dielectric antennas were performed on beef livers. Irradiation results were considered by microwave theory and ray optics.

  13. テフロンフレキシブル導波管によるジャイロトロンFUCW-Ⅰの出力測定

    OpenAIRE

    寺中, 正人; 土井, 昭孚; 立川, 敏明; 光藤, 誠太郎; 斉藤, 輝雄; 出原, 敏孝; 難波, 経豊

    2007-01-01

    In order to develop the millimeter and sub-millimeter wave catheter irradiation apparatus for the living body, the output power by the catheter transmission using Gyrotron FUCW-Ⅰ(GYCOM, Russia) was measured at 300 GHz.The output power was measured by water loading. That was transferred by some flexible Teflon rod waveguides and that was decreased according to Teflon rod length. And we measured the power using dielectric Anti-Reflecting (AR) antennas too.

  14. Wills Plasma Physics Department annual progress report 1984

    International Nuclear Information System (INIS)

    The experimental program continued to be centred around work on the research tokamak TORTUS. Projects included the guiding of Alfven waves along helical magnetic field lines, the excitation of Alfven waves by an antenna and antenna designs for Alfven wave heating. Supporting work included studies of surface waves using the linear SUPPER IV machine, development of lasers and laser diagnostics, development of a neutral particle analyser for measuring ion temperatures, and development of a continuously tunable gyrotron

  15. Free-space power transmission

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    NASA Lewis Research Center organized a workshop on technology availability for free-space power transmission (beam power). This document contains a collection of viewgraph presentations that describes the effort by academia, industry, and the national laboratories in the area of high-frequency, high-power technology applicable to free-space power transmission systems. The areas covered were rectenna technology, high-frequency, high-power generation (gyrotrons, solar pumped lasers, and free electron lasers), and antenna technology.

  16. Preliminary conceptual design of DEMO EC system

    Energy Technology Data Exchange (ETDEWEB)

    Garavaglia, S., E-mail: garavaglia@ifp.cnr.it; Bin, W.; Bruschi, A.; Granucci, G.; Moro, A.; Rispoli, N. [Institute of Plasma Physics “P.Caldirola”, National Research Council of Italy, Milan (Italy); Grossetti, G.; Strauss, D. [IAM-AWP, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Jelonnek, J. [IHM, KIT, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Tran, Q. M. [CRPP, EPFL, EURATOM Association, CH-1015 Lausanne (Switzerland); Franke, T. [EUROfusion Consortium, Boltzmannstr. 2, D-85748 Garching (Germany); Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-12-10

    In the framework of EUROfusion Consortium the Work Package Heating and Current Drive addresses the engineering design and R&D for the electron cyclotron, ion cyclotron and neutral beam systems. This paper reports the activities performed in 2014, focusing on the work done regarding the input for the conceptual design of the EC system, particularly for the gyrotron, the transmission line and the launchers.

  17. Mode competition in fourth-harmonic magnicon amplifiers

    International Nuclear Information System (INIS)

    The magnicon is under development as an efficient high-power microwave amplifier for powering the next generation of electron accelerators for high-energy physics research. In the magnicon RF amplifier, the drive and gain cavities are cylindrical deflection cavities which operate in a rotating TM110-mode and spin up an electron beam to high transverse momentum. As a result of the rotating-mode interaction, the electron beam entry point into the output cavity rotates about the axis at the drive frequency. The gyrotron-like output cavity can be operated at m times the drive frequency by using a mode with an azimuthal index of m, as this mode rotates at m-1 times its RF frequency, thus maintaining synchronism with the electron beam. Previous frequency-multiplying magnicons have used m = 2; in this paper it is shown that magnicons with m = 4 may be practical, provided one also operates the output cavity at the m/2 harmonic of the cyclotron frequency. Operation at higher harmonics lowers the frequency of the deflection cavities allowing lower RF fields, reducing magnet cost and complexity; and a larger electron beam, relaxing beam quality constraints. On the other hand, higher order azimuthal-index magnicon modes interacting at higher order cyclotron interactions are subject to competition with nonsynchronous (gyrotron) modes and are more sensitive to electron beam scanning angle spread. A time-dependent multimode gyrotron code has been modified to examine competition in the output cavity between the phase-synchronous operating mode and other nonsynchronous modes which interact via the conventional gyrotron interaction

  18. Structure Design and Analysis of High-Voltage Power Supply for ECRH

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; HUANG Yiyun; ZHAO Yanping; ZHANG Jian; YANG Lei; GUO Wenjun

    2014-01-01

    In order to develop a high-voltage power supply (HVPS) with high quality parameters,not only its electrical circuit but also its structure should be studied in detail.In this paper,the structure design of the collector power supply for gyrotron is discussed first.Then the electrical field and potential simulations of its main devices are analyzed.Finally,relevant calculations and conclusions are given.

  19. Fusion development and technology

    International Nuclear Information System (INIS)

    This report discusses the following: superconducting magnet technology; high field superconductors; advanced magnetic system and divertor development; poloidal field coils; gyrotron development; commercial reactor studies--aries; ITER physics: alpha physics and alcator R ampersand D for ITER; lower hybrid current drive and heating in the ITER device; ITER superconducting PF scenario and magnet analysis; ITER systems studies; and safety, environmental and economic factors in fusion development

  20. High-power microwave transmission systems for electron-cyclotron-resonance plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, R.J.

    1991-08-01

    This progress report is for the sixth year of a grant from the US Department of Energy for the design, development, and fabrication of ECRH transmission and mode conversion systems to transport microwave power from a gyrotron to a magnetically confined plasma. The design and low-power testing of new and improved components for such systems and development of underlying theory is the focus of this project. Devising and improving component testing and diagnostic techniques is also an important part of this effort. The development of possible designs for sections of gyrotrons themselves, such as tapers or Vlasov-type launchers, in support of the Varian gyrotron development program is also considered when appropriate. We also provide support to other groups working on ECR heating of magnetically confined plasmas such as the groups at General Atomics, the University of Texas at Austin, and Lawrence Livermore National Laboratory. During the last year, we designed and had fabricated a two-dimensional Vlasov antenna system for a 110 GHz TE{sub 15,2} mode gyrotron for possible use at General Atomics. The system included the launcher section, a visor, main reflector, and focusing reflector. Programs to generate the tool-path profiles to cut the General Atomics'' Vlasov components on a milling machine were developed. We have also developed state-of-the art theory and programs for three-dimensional whispering-gallery-mode Vlasov antenna systems. A design for a 110 GHz TE{sub 01}-TE{sub 15,2} mode converter system for cold testing WGM Vlasov antenna systems was developed and is currently being fabricated also.

  1. Simplified THz Instrumentation for High-Field DNP-NMR Spectroscopy.

    Science.gov (United States)

    Maly, Thorsten; Sirigiri, Jagadishwar R

    2012-07-01

    We present an alternate simplified concept to irradiate a nuclear magnetic resonance sample with terahertz (THz) radiation for dynamic nuclear polarization (DNP) experiments using the TE(01) circular waveguide mode for transmission of the THz power and the illumination of the DNP sample by either the TE(01) or TE(11) mode. Using finite element method and 3D electromagnetic simulations we demonstrate that the average value of the transverse magnetic field induced by the THz radiation and responsible for the DNP effect using the TE(11) or the TE(01) mode are comparable to that generated by the HE(11) mode and a corrugated waveguide. The choice of the TE(11)/TE(01) mode allows the use of a smooth-walled, oversized waveguide that is easier to fabricate and less expensive than a corrugated waveguide required for transmission of the HE(11) mode. Also, the choice of the TE(01) mode can lead to a simplification of gyrotron oscillators that operate in the TE(0n) mode, by employing an on-axis rippled-wall mode converter to convert the TE(0n) mode into the TE(01) mode either inside or outside of the gyrotron tube. These novel concepts will lead to a significant simplification of the gyrotron, the transmission line and the THz coupler, which are the three main components of a DNP system. PMID:22977293

  2. Extension of high T{sub e} regime with upgraded electron cyclotron resonance heating system in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, H., E-mail: takahashi.hiromi@LHD.nifs.ac.jp; Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Nagaoka, K.; Osakabe, M.; Yamada, I.; Nakano, H.; Yokoyama, M.; Ido, T.; Shimizu, A.; Seki, R.; Ida, K.; Yoshinuma, M. [National Institute for Fusion Science, Toki 509-5292 (Japan); and others

    2014-06-15

    Enhancement of the output power per gyrotron has been planned in the Large Helical Device (LHD). Three 77-GHz gyrotrons with an output power of more than 1 MW have been operated. In addition, a high power gyrotron with the frequency of 154 GHz (1 MW/5 s, 0.5 MW/CW) was newly installed in 2012, and the total injection power of Electron cyclotron resonance heating (ECRH) reached 4.6 MW. The operational regime of ECRH plasma on the LHD has been extended due to the upgraded ECRH system such as the central electron temperature of 13.5 keV with the line-averaged electron density n{sub e-fir} = 1 × 10{sup 19} m{sup −3}. The electron thermal confinement clearly improved inside the electron internal transport barrier, and the electron thermal diffusivity reached neoclassical level. The global energy confinement time increased with increase of n{sub e-fir}. The plasma stored energy of 530 kJ with n{sub e-fir} = 3.2 × 10{sup 19} m{sup −3}, which is 1.7 times larger than the previous record in the ECRH plasma in the LHD, has been successfully achieved.

  3. Self-consistent modeling of terahertz waveguide and cavity with frequency-dependent conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y. J.; Chu, K. R., E-mail: krchu@yahoo.com.tw [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Thumm, M. [IHM and IHE, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2015-01-15

    The surface resistance of metals, and hence the Ohmic dissipation per unit area, scales with the square root of the frequency of an incident electromagnetic wave. As is well recognized, this can lead to excessive wall losses at terahertz (THz) frequencies. On the other hand, high-frequency oscillatory motion of conduction electrons tends to mitigate the collisional damping. As a result, the classical theory predicts that metals behave more like a transparent medium at frequencies above the ultraviolet. Such a behavior difference is inherent in the AC conductivity, a frequency-dependent complex quantity commonly used to treat electromagnetics of metals at optical frequencies. The THz region falls in the gap between microwave and optical frequencies. However, metals are still commonly modeled by the DC conductivity in currently active vacuum electronics research aimed at the development of high-power THz sources (notably the gyrotron), although a small reduction of the DC conductivity due to surface roughness is sometimes included. In this study, we present a self-consistent modeling of the gyrotron interaction structures (a metallic waveguide or cavity) with the AC conductivity. The resulting waveguide attenuation constants and cavity quality factors are compared with those of the DC-conductivity model. The reduction in Ohmic losses under the AC-conductivity model is shown to be increasingly significant as the frequency reaches deeper into the THz region. Such effects are of considerable importance to THz gyrotrons for which the minimization of Ohmic losses constitutes a major design consideration.

  4. ECH system and its application to long pulse discharge in large helical device

    International Nuclear Information System (INIS)

    We have developed and constructed an ECH system for the large helical device (LHD). The ECH system consists of 0.5 MW, 84 GHz range and 168 GHz gyrotrons, high voltage power supplies, long distance transmission lines, and in-vessel quasi-optical antennas. It has been improved step by step. At the third campaign of LHD experiments, three 84 GHz range (two 82.6 GHz and one 84 GHz) and three 168 GHz gyrotrons are operated and ECH power can be injected from four antennas vertically and two horizontally. This complicated system is remotely controlled and monitored by fully GUI (Graphical User Interface) control panels realized on PC via TCP (transmission control protocol) communication. Over 10000 shots of gyrotron power have been injected steadily into the LHD during the experimental campaigns on this system. One line of the system (84 GHz line) is specially prepared for the experiments of steady state plasma production. Using this line, plasma sustainment for 2 min was successfully achieved by only ECH power. Injected ECH power was 50 kW with 95% duty factor. The electron density and temperature of the sustained plasma are measured to be 0.3-0.5x1018 m-3 and ∼650 eV. Ion temperature measured by Doppler broadening of the impurity radiation line was kept constant at ∼300 eV during RF injection

  5. ECH system and its application to long pulse discharge in large helical device

    Energy Technology Data Exchange (ETDEWEB)

    Shimozuma, T.; Kubo, S.; Sato, M.; Idei, H.; Takita, Y.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Yoshimura, Y.; Ohkubo, K.; Funaba, H.; Inagaki, S.; Kobuchi, T.; Masuzaki, S.; Muto, S.; Shoji, M.; Suzuki, H.; Noda, N.; Nakamura, Y.; Kawahata, K.; Ohyabu, N.; Motojima, O

    2001-01-01

    We have developed and constructed an ECH system for the large helical device (LHD). The ECH system consists of 0.5 MW, 84 GHz range and 168 GHz gyrotrons, high voltage power supplies, long distance transmission lines, and in-vessel quasi-optical antennas. It has been improved step by step. At the third campaign of LHD experiments, three 84 GHz range (two 82.6 GHz and one 84 GHz) and three 168 GHz gyrotrons are operated and ECH power can be injected from four antennas vertically and two horizontally. This complicated system is remotely controlled and monitored by fully GUI (Graphical User Interface) control panels realized on PC via TCP (transmission control protocol) communication. Over 10000 shots of gyrotron power have been injected steadily into the LHD during the experimental campaigns on this system. One line of the system (84 GHz line) is specially prepared for the experiments of steady state plasma production. Using this line, plasma sustainment for 2 min was successfully achieved by only ECH power. Injected ECH power was 50 kW with 95% duty factor. The electron density and temperature of the sustained plasma are measured to be 0.3-0.5x10{sup 18} m{sup -3} and {approx}650 eV. Ion temperature measured by Doppler broadening of the impurity radiation line was kept constant at {approx}300 eV during RF injection.

  6. 60kV, 10Amp DC power supply multiple input control and monitoring provision for the operation of various high power RF generation systems

    International Nuclear Information System (INIS)

    A 60 kV, 10 A DC power supply is used for testing of high power RF and microwave tubes e.g. Klystron, Gyrotron. Two 500 kW, 3.7 GHz klystrons, and one 82.6 GHz Gyrotron are located in SST1 Hall where as 200 kW; 28 GHz Gyrotron is located in Aditya Hall. The same power supply is required to operate, control and monitor various systems at different locations with easy change over from one system to other as per experimental requirements. An off line, control change over system, is designed to accomplish the above requirements, with control panels installed at desired different locations. The input (0 to 11 kV) A.C. voltage to power supply is given from a motorized voltage variation system (VVS). The control panels provide indication of A.C. input voltage to power supply from 11 kV potential transformers of VVS. In addition, the control panel is provided with 11 kV circuit breaker status indication and control i.e. Emergency OFF switch. The control panels are designed and developed indigenously which are successfully installed and are in continuous use for the safe and easy operation of different high power rf systems from the same DC power supply. The paper presents the design of the controls, monitoring and indications. Safety aspects of the system are also highlighted.

  7. Millimeter wave study program. Final report

    International Nuclear Information System (INIS)

    The purpose of this program was to study the various approaches to building an amplifier to produce 100 kW or more cw power at 120 GHz to decide on an optimum approach, and to perform design calculations. The study has led to the conclusion that a cyclotron resonance amplifier (gyrotron) is the optimum approach for 100 kW and that this type of interaction offers the best possibilities for going to still higher power levels. This report includes discussion in depth of all the topics and approaches considered in the study. Sections 2 and 3 deal with output waveguide and window designs. The fourth section discusses linear-beam amplifiers. The fifth section considers periodic-beam (other than cyclotron resonance) devices. Cyclotron resonance devices are considered in detail. Arguments are given leading to the choice of the gyrotron as the optimum approach in section 7. Design calculations for a 100 kW gyrotron amplifier are given based on the background and theory presented in section 6

  8. 3.6MW Power Supply System of the 170GHz ECH&CD System in KSTAR

    Directory of Open Access Journals (Sweden)

    Joung Jin-Hyun

    2012-09-01

    Full Text Available A 3.6 MW (-66 kV/55 A Gyrotron power supply system was developed for the 170 GHz ECH&CD gyrotron system in KSTAR. This power supply system consists of Cathode Power Supply(CPS, Anode Power Supply(APS and Body Power Supply(BPS. The CPS is using the Pulse Step Modulation by the 32set of IGBT choppers. The respons time of Chopper is very fast. So the cathode voltaget is able to be controlled rapidly. The APS is a sort of voltage devider using zener and switch component. It was achieved 3kHz modulation operation. The BPS is combined the commercial power supply and special high voltage switches. It is very simple topology but 5kHz modulation was accomplished easily. Theses power supply system were installed and commissioned successfully in 2011. This paper presents the topology of the each power supply and test result for 170 GHz gyrotron in KSTAR.

  9. Design of the 2D electron cyclotron emission imaging instrument for the J-TEXT tokamak

    Science.gov (United States)

    Pan, X. M.; Yang, Z. J.; Ma, X. D.; Zhu, Y. L.; Luhmann, N. C.; Domier, C. W.; Ruan, B. W.; Zhuang, G.

    2016-11-01

    A new 2D Electron Cyclotron Emission Imaging (ECEI) diagnostic is being developed for the J-TEXT tokamak. It will provide the 2D electron temperature information with high spatial, temporal, and temperature resolution. The new ECEI instrument is being designed to support fundamental physics investigations on J-TEXT including MHD, disruption prediction, and energy transport. The diagnostic contains two dual dipole antenna arrays corresponding to F band (90-140 GHz) and W band (75-110 GHz), respectively, and comprises a total of 256 channels. The system can observe the same magnetic surface at both the high field side and low field side simultaneously. An advanced optical system has been designed which permits the two arrays to focus on a wide continuous region or two radially separate regions with high imaging spatial resolution. It also incorporates excellent field curvature correction with field curvature adjustment lenses. An overview of the diagnostic and the technical progress including the new remote control technique are presented.

  10. Peculiar Velocity Constraints from Five-Band SZ Effect Measurements Towards RX J1347.5-1145 with MUSIC and Bolocam from the CSO

    CERN Document Server

    Sayers, Jack; Glenn, Jason; Golwala, Sunil R; Maloney, Philip R; Siegel, Seth R; Wheeler, Jordan; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G; Day, Peter K; Downes, Thomas P; Duan, Ran P; Gao, Jiansong; Hollister, Matthew I; Lam, Albert; LeDuc, Henry G; Mazin, Benjamin A; McHugh, Sean G; Miller, David A; Mroczkowski, Tony K; Noroozian, Omid; Nguyen, Hien T; Radford, Simon J; Schlaerth, James A; Vayonakis, Anastasios; Wilson, Philip R; Zmuidzinas, Jonas

    2015-01-01

    We present Sunyaev-Zel'dovich (SZ) effect measurements from wide-field images towards the galaxy cluster RX J1347.5-1145 obtained from the Caltech Submillimeter Observatory with the Multiwavelength Submillimeter Inductance Camera (MUSIC) at 147, 213, 281, and 337 GHz and with Bolocam at 140 GHz. As part of our analysis, we have used higher frequency data from Herschel-SPIRE and previously published lower frequency radio data to subtract the signal from the brightest dusty star-forming galaxies behind RX J1347.5-1145 and from the AGN in RX J1347.5-1145's BCG. Using these five-band SZ effect images, combined with previously published X-ray spectroscopic measurements of the temperature of the intra-cluster medium (ICM) from Chandra, we constrain the ICM optical depth to be $\\tau_e = 2.73^{+0.38}_{-0.39} \\times 10^{-3}$ and the ICM line of sight peculiar velocity to be $v_{pec} = -1260^{+760}_{-530}$ km s$^{-1}$. The errors for both quantities are limited by measurement noise rather than calibration uncertainties...

  11. Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

    CERN Document Server

    Czakon, N G; Mantz, A; Golwala, S R; Downes, T P; Koch, P M; Lin, K -Y; Molnar, S M; Moustakas, L A; Mroczkowski, T; Pierpaoli, E; Shitanishi, J A; Siegel, S; Umetsu, K

    2014-01-01

    We present scaling relations between the integrated Sunyaev-Zel'dovich Effect (SZE) signal, $Y_{\\rm SZ}$, its X-ray analogue, $Y_{\\rm X}$$\\equiv$$M_{\\rm gas}$$T_{\\rm X}$, and total mass, $M_{\\rm tot}$, for the 45 galaxy clusters in the Bolocam X-ray-SZ (BOXSZ) sample. All parameters are integrated within $r_{2500}$. $Y_{2500}$ values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory (CSO). The temperature, $T_{\\rm X}$, and mass, $M_{\\rm gas,2500}$, of the intracluster medium are determined using X-ray data collected with \\emph{Chandra}, and $M_{\\rm tot}$ is derived from $M_{\\rm gas}$ using a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including: selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the $Y_{2500}$-$Y_{\\rm X}$ scaling to have a logarithmic slope of $0.84\\pm0.07$, and a fractional intrinsic scatt...

  12. Detection of the tSZ effect with the NIKA camera

    Science.gov (United States)

    Comis, B.; Adam, R.; Adane, A.; Ade, P.; André, P.; Beelen, A.; Belier, B.; Benoît, A.; Bideaud, A.; Billot, N.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; D'Addabbo, A.; Désert, F.-X.; Doyle, S.; Goupy, J.; Kramer, C.; Leclercq, S.; Macías-Pérez, J. F.; Martino, J.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Pajot, F.; Pascale, E.; Pointecouteau, E.; Ponthieu, N.; Revéret, V.; Rodriguez, L.; Savini, G.; Schuster, K.; Sievers, A.; Tucker, C.; Zylka, R.

    2013-11-01

    We present the first detection of the thermal Sunyaev-Zel'dovich (tSZ) effect from a cluster of galaxies performed with a KIDs (Kinetic Inductance Detectors) based instrument. The tSZ effect is a distortion of the black body CMB (Cosmic Microwave Background) spectrum produced by the inverse Compton interaction of CMB photons with the hot electrons of the ionized intra-cluster medium. The massive, intermediate redshift cluster RX J1347.5-1145 has been observed using {NIKA} (New IRAM KIDs arrays), a dual-band (140 and 240 GHz) mm-wave imaging camera, which exploits two arrays of hundreds of KIDs: the resonant frequencies of the superconducting resonators are shifted by mm-wave photons absorption. This tSZ cluster observation demonstrates the potential of the next generation {NIKA2} instrument, being developed for the 30m telescope of IRAM, at Pico Veleta (Spain). {NIKA2} will have 1000 detectors at 140GHz and 2x2000 detectors at 240GHz, providing in that band also a measurement of the linear polarization. {NIKA2} will be commissioned in 2015.

  13. Detection of the tSZ effect with the NIKA camera

    CERN Document Server

    Comis, B; Macías-Pérez, J F; Adane, A; Ade, P; André, P; Beelen, A; Belier, B; Benoît, A; Bideaud, A; Billot, N; Boudou, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; D'Addabbo, A; Désert, F -X; Doyle, S; Goupy, J; Kramer, C; Leclercq, S; Martino, J; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Ponthieu, N; Revéret, V; Rodriguez, L; Savini, G; Schuster, K; Sievers, A; Tucker, C; Zylka, R

    2013-01-01

    We present the first detection of the thermal Sunyaev-Zel'dovich (tSZ) effect from a cluster of galaxies performed with a KIDs (Kinetic Inductance Detectors) based instrument. The tSZ effect is a distortion of the black body CMB (Cosmic Microwave Background) spectrum produced by the inverse Compton interaction of CMB photons with the hot electrons of the ionized intra-cluster medium. The massive, intermediate redshift cluster RX J1347.5-1145 has been observed using NIKA (New IRAM KIDs arrays), a dual-band (140 and 240 GHz) mm-wave imaging camera, which exploits two arrays of hundreds of KIDs: the resonant frequencies of the superconducting resonators are shifted by mm-wave photons absorption. This tSZ cluster observation demonstrates the potential of the next generation NIKA2 instrument, being developed for the 30m telescope of IRAM, at Pico Veleta (Spain). NIKA2 will have 1000 detectors at 140GHz and 2x2000 detectors at 240GHz, providing in that band also a measurement of the linear polarization. NIKA2 will ...

  14. The steady-state ECRH-system at Wendelstein7-X

    International Nuclear Information System (INIS)

    Electron Cyclotron Resonance Heating (ECRH) is the main heating system for the Wendelstein7-X (W7-X) stellarator and the only one for CW-operation in the first stage. The mission of W7-X, which is presently under construction at IPP-Greifswald, is to demonstrate the inherent steady state capability of stellarators at reactor relevant plasma parameters. A modular 10 MW ECRH plant at 140 GHz with 1 MW CW-capability power for each module is under construction to meet the scientific objectives. Simulations of different ECRH scenarios, which are foreseen for W7-X operation and base on ray- tracing calculations and confinement studies, will be presented. A steady state ECRH has specific requirements on the stellarator machine itself, on the ECRH-sources, transmissions elements and on the experimental environment. In particular all elements have to be sufficiently cooled, screened and armoured against microwaves. The commissioning of the ECRH plant is well under way, the strategy and status of the project will be reported. First full power, CW integral tests of one ECRH module have been performed. A large microwave stray radiation chamber for integrated in-vessel component tests had been brought into operation. A bi-axially movable, motor driven ECRH antenna mock-up was build and is tested for reliability now. A strategy for the commissioning and the first experimental campaign at W7-X has been developed. (author)

  15. High-performance BiCMOS technologies without epitaxially-buried subcollectors and deep trenches

    Science.gov (United States)

    Heinemann, B.; Barth, R.; Knoll, D.; Rücker, H.; Tillack, B.; Winkler, W.

    2007-01-01

    A 0.25 µm SiGe:C BiCMOS technology family (SG25H) with high-speed npn and pnp transistors for different performance requirements is presented. A CMOS-friendly integration scheme is realized by using collector wells, implanted after shallow trench formation, and avoiding deep trenches and extra collector sinkers. Three process variants are offered. The key bipolar transistor of the SG25H1 process is a 200 GHz npn device. The SG25H3 process offers three different types of npn HBTs. The performance ranges from fT/fmax /BVCEo values of 110 GHz/180 GHz/2.3 V for the high-speed (HS) device to 50 GHz/140 GHz/4.5 V for the medium voltage (MV) device and 30 GHz/80 GHz/6.5 V for the high-voltage (HV) transistor. The SG25H2 process provides in addition to npn transistors similar to those of SG25H1 and H3 a very high-speed SiGe:C pnp HBT with fT/fmax/BVCEo values of 90 GHz/120 GHz/2.8 V.

  16. Integrated Operating Scenario to Achieve 100-Second, High Electron Temperature Discharge on EAST

    Science.gov (United States)

    Qian, Jinping; Gong, Xianzu; Wan, Baonian; Liu, Fukun; Wang, Mao; Xu, Handong; Hu, Chundong; Wang, Liang; Li, Erzhong; Zeng, Long; Ti, Ang; Shen, Biao; Lin, Shiyao; Shao, Linming; Zang, Qing; Liu, Haiqing; Zhang, Bin; Sun, Youwen; Xu, Guosheng; Liang, Yunfeng; Xiao, Bingjia; Hu, Liqun; Li, Jiangang; EAST Team

    2016-05-01

    Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of >4.5 keV, and a central density ne(0)˜2.5×1019 m-3. The plasma current was nearly non-inductive (Vloop heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated “hybrid” operating scenario of interest to ITER and CFETR. supported by the National Magnetic Confinement Fusion Science Foundation of China (Nos. 2015GB102000 and 2014GB103000)

  17. Integrated Operating Scenario to Achieve 100-Second, High Electron Temperature Discharge on EAST

    Institute of Scientific and Technical Information of China (English)

    QIAN Jinping; GONG Xianzu; WAN Baonian; LIU Fukun; WANG Mao; XU Handong; HU Chundong

    2016-01-01

    Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape,divertor heat flux,particle exhaust,wall conditioning,impurity management,and the coupling of multiple heating and current drive power.A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA,q95 ≈7.0,a peak electron temperature of >4.5 keV,and a central density ne(0)~ 2.5×1019 m-3.The plasma current was nearly non-inductive (Vloop <0.05 V,poloidal beta ~ 0.9) driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz,1.4 MW lower hybrid wave at 4.6 GHz,0.5 MW electron cyclotron heating at 140 GHz,and 0.4 MW modulated neutral deuterium beam injected at 60 kV.This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating,current drive,and energy confinement of stationary plasma on EAST.It further introduced an example of integrated “hybrid” operating scenario of interest to ITER and CFETR.

  18. A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology

    Science.gov (United States)

    Ou-Peng, Li; Yong, Zhang; Rui-Min, Xu; Wei, Cheng; Yuan, Wang; Bing, Niu; Hai-Yan, Lu

    2016-05-01

    Design and characterization of a G-band (140-220 GHz) terahertz monolithic integrated circuit (TMIC) amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm InGaAs/InP double heterojunction bipolar transistor (DHBT). An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the InP substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140-190 GHz respectively. The saturation output powers are -2.688 dBm at 210 GHz and -2.88 dBm at 220 GHz, respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications. Project supported by the National Natural Science Foundation of China (Grant No. 61501091) and the Fundamental Research Funds for the Central Universities of Ministry of Education of China (Grant Nos. ZYGX2014J003 and ZYGX2013J020).

  19. Vibration-free Cooler for the METIS Instrument Using Sorption Compressors

    NARCIS (Netherlands)

    Wu, Y.; Mulder, T.; Vermeer, C.H.; Holland, H.J.; Benthem, B.; Brake, ter H.J.M.

    2015-01-01

    METIS is the “Mid-infrared ELT Imager and Spectrograph” for the European Extremely Large Telescope (E-ELT) that will cover the thermal/mid-infrared wavelength range from 3-14 micron. Starting from a pumped nitrogen line at 70K, it requires cryogenic cooling of detectors and optics at 40 K (1.4 W), 2

  20. Nonsequential double ionization as a completely classical photoelectric effect.

    Science.gov (United States)

    Ho, Phay J; Panfili, R; Haan, S L; Eberly, J H

    2005-03-11

    We introduce a unified and simplified theory of atomic double ionization. Our results show that at high laser intensities (I>/=10(14) W/cm(2)) purely classical correlation is strong enough to account for all of the main features observed in experiments to date.

  1. High performance metal-supported solid oxide fuel cells with Gd-doped ceria barrier layers

    DEFF Research Database (Denmark)

    Klemensø, Trine; Nielsen, Jimmi; Blennow Tullmar, Peter;

    2011-01-01

    , and an electrochemical performance beyond the state-of-the-art anode-supported SOFC is demonstrated possible, by introducing a CGO barrier layer in combination with Sr-doped lanthanum cobalt oxide (LSC) cathode. Area specific resistances (ASR) down to 0.27 Ω cm2, corresponding to a maximum power density of 1.14 W cm−2...

  2. 27 CFR 9.175 - Dos Rios.

    Science.gov (United States)

    2010-04-01

    ...; (3) Iron Peak, California—Mendocino County, 1967 edition, revised 1994; and (4) Covelo West... 2208 benchmark near the southeast corner of section 36, T22N, R14W), and, returning to the Laytonville... between the Laytonville and Iron Peak maps, and, returning to the Iron Peak map, continue along...

  3. Sphingoid esters from the molecular distillation of squid oil: A preliminary bioactivity determination.

    Science.gov (United States)

    Saliu, Francesco; Longhin, Eleonora; Salanti, Anika; Degano, Ilaria; Della Pergola, Roberto

    2016-06-15

    A mixture of sphingoid esters was isolated (1.4% w/w) from the molecular distillation of crude squid visceral oil. A preliminary investigation on the bioactivity profile and toxic potential of this residue was carried out by in vitro experiments. No cytotoxicity and a moderate lipase inhibition activity were highlighted. PMID:26868543

  4. Nitrogen laser with a pulse repetition rate of 11 kHz and a beam divergence of 0.5 mrad

    International Nuclear Information System (INIS)

    A repetitively pulsed high-frequency UV nitrogen laser based on magnetic pulse compression (MPC) circuit is developed. The special characteristics of laser operation at pulse repetition rates up to 11 kHz are studied. Lasing with an average power of 1.4 W for a beam divergence of less than 0.5 mrad is obtained. (lasers)

  5. 75 FR 63509 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

    Science.gov (United States)

    2010-10-15

    ..., Workers' Wages Were Reported Under 14 W. Administrative Services, Agora, Inc. 73,395 Roddie Trucking, LLC..., Patient Accounting Dept., Leased Workers, Liberty and Tritech. 74,040 Cemex Construction Wampum, PA... Employment and Training Administration Notice of Determinations Regarding Eligibility To Apply for...

  6. Dicty_cDB: Contig-U13236-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .3 4 ( AC173720 ) Strongylocentrotus purpuratus clone R3-1008M14, W... 38 2.4 5 ( AY858561 ) Hermeuptychia hermes...6 2.6 2 ( AY858562 ) Hermeuptychia hermes isolate CTBEH144 cytochrome ... 36 2.7 2 ( CU442744 ) Pig DNA sequ...ence *** SEQUENCING IN PROGRESS *** f... 40 2.7 2 ( AY858563 ) Hermeuptychia hermes

  7. 1178 nm all Yb-fiber laser source power-scaled by solid-core photonic bandgap fiber for 589nm generation

    DEFF Research Database (Denmark)

    Maruyama, H.; Shirakawa, A.; Ueda, K.I.;

    2009-01-01

    Here we report an 1178 nm all Yb-fiber laser source power-scaled by solid-core photonic bandgap fiber (SC-PBGF) for 589 nm generation. A 1.4 W output at 589 nm with an input power of 9 W at 1178 nm were obtained. One important advantage of PBGF is distributed filtering. Hence the gain spectrum can...

  8. Efficacy of a topically administered combination of emodepside and praziquantel against mature and immature Ancylostoma tubaeforme in domestic cats

    NARCIS (Netherlands)

    Altreuther, G.; Borgsteede, F.H.M.; Buch, J.; Charles, S.D.; Cruthers, L.; Epe, C.; Young, D.R.; Krieger, K.J.

    2005-01-01

    This paper reports the efficacy of emodepside/praziquantel spot¿on (Profender®, Bayer AG, Leverkusen, Germany), a novel broadspectrum anthelmintic for dermal application, against L4 larvae and immature adult and adult stages of Ancylostoma tubaeforme in cats. The formulation contains 2.14% (w/w) emo

  9. Development of high voltage power supply for the KSTAR 170 GHz ECH and CD system

    International Nuclear Information System (INIS)

    Highlights: • A 3.6 MW (−66 kV/55 A) gyrotron power supply system was developed for the 170 GHz ECH system in KSTAR. • The main power supply includes a total of 32 PSM based HV power supply modules. • The voltage regulation of individual HV power module and LV power module is 3 kV and 0.5 kV, respectively. • The gyrotron is protected by means of a fast solid-state switch (MOS-FET). • The HV switching system can turn off the 60 kV to the cathode within 3 μs in the event of gyrotron faults. -- Abstract: A 3.6 MW (66 kV/55 A) DC power supply system was developed for the 170 GHz EC H and CD system in KSTAR. The power supply system consists of a cathode power supply (CPS), an anode power supply (APS) and a body power supply (BPS). The cathode power supply is capable of supplying a maximum voltage of −66 kV and a current of 55 A to the cathode with respect to the collector using pulse step modulation (PSM). The high voltage switching system for the cathode is made by a fast MOS-FET solid-state switch which can turn off the high voltage to the cathode within 3 μs in the occurrence of gyrotron faults. The APS is a voltage divider system consisting of a fixed resistor and zener diode units with the capability of 60 kV stand-off voltage. The anode voltage with respect to the cathode is controlled in a range of 0–60 kV by turning the MOS-FET switches connected in parallel to each zener diode on and off. For high frequency current modulation of the gyrotron, the parallel discharge switch is introduced between the cathode and anode in order to clamp the charged voltage in the stray capacitance. The BPS is a DC power supply with the capability of 50 kV/160 mA. The nominal operation parameter of BPS was 23 kV and 10 mA, respectively, and the voltage output is regulated with a stability of 0.025% of the rated voltage. The series MOS-FET solid-state switch is used for on/off modulation in the body voltage sychronizing with anode voltage. The parallel discharge

  10. Extension of high T{sub e} regime with upgraded ECRH system in the LHD

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, H.; Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Nagaoka, K.; Osakabe, M.; Yamada, I.; Nakano, H.; Yokoyama, M.; Ido, T.; Shimizu, A.; Seki, R.; Ida, K.; Yoshinuma, M. [National Institute for Fusion Science, Toki, 509-5292 (Japan); and others

    2014-02-12

    Enhancement of the output power per gyrotron has been planned in the Large Helical Device (LHD). Three 77-GHz gyrotrons with an output power of more than 1 MW have been operated. In addition, a high power gyrotron with the frequency of 154 GHz (1 MW/5 s, 0.5 MW/CW) was newly installed in 2012 and the total injection power of ECRH reached 4.6 MW. The operational regime of ECRH plasma on the LHD has been extended due to the upgraded ECRH system such as the central electron temperature T{sub e0} = 13.5 keV with n{sub e} = 1×10{sup 19}m{sup −3}. In the LHD, an electron-internal-transport barrier (e-ITB) related to the production of high T{sub e} plasmas has been realized by strongly centre-focused ECRH. The electron thermal confinement clearly improved inside the e-ITB. The radial electric field was measured using the heavy ion beam probe. The formation of the positive E{sub r} was observed in the core region, which well agreed with the prediction of the neoclassical transport theory. The energy confinement characteristics have been investigated in the ECRH plasmas. It was found that higher plasma stored energy and lower radiation power was realized in the outward configuration. The plasma stored energy of 530 kJ with n{sub e} = 3.2×10{sup 19}m{sup −3}, which is the 1.7 times larger than the previous record in the ECRH plasma in the LHD, has been successfully achieved.

  11. DIII-D electron cyclotron heating 2 MW upgrade project. Final report for the period FY89 through FY97

    International Nuclear Information System (INIS)

    The 2 MW, 110 GHz ECH system was based on the General Atomics Proposal to the Department of Energy: DIII-D Fusion Research Program Vol. I Technical, and Vol. II Cost (GACP-72-166, July 1987 and revised). This proposal was reviewed in August 1987 by a senior technical review committee, who recommended to vigorously pursue increasing the ECH power to 6 MW. The realization of the higher frequency and power ECH on DIII-D was recognized by the committee to be important, not only for the DIII-D program, but also for future devices and the whole ECH area. Subsequently, an engineering cost and schedule review was conducted by DOE-OAK which confirmed the GA costs and schedules and recommended proceeding directly to 10 MW. However, because of budgetary constraints, in the April 1988 Field Task Proposal submission, GA proposed a phased ECH approach, Phase I being 2 MW and Phase II increasing the power to 10 MW. After review, DOE instructed GA to initiate the prototype 2 MW, 110 GHz program. The contract to procure four 500 kW, 110 GHz, 10 s gyrotrons from Varian Associates was initiated in April 1989 with final delivery by November 1990. Because of difficulties in spreading the energy of the electron beam over the collector area, the testing of the first gyrotron delayed its delivery until February 1991. The second gyrotron was able to operate for 1 s at 500 kW and 2 s at 300 kW, but failed when the cavity suffered thermal damage

  12. Millimeter-wave imaging diagnostics systems on the EAST tokamak (invited)

    Science.gov (United States)

    Zhu, Y. L.; Xie, J. L.; Yu, C. X.; Zhao, Z. L.; Gao, B. X.; Chen, D. X.; Liu, W. D.; Liao, W.; Qu, C. M.; Luo, C.; Hu, X.; Spear, A. G.; Luhmann, N. C.; Domier, C. W.; Chen, M.; Ren, X.; Tobias, B. J.

    2016-11-01

    Millimeter-wave imaging diagnostics, with large poloidal span and wide radial range, have been developed on the EAST tokamak for visualization of 2D electron temperature and density fluctuations. A 384 channel (24 poloidal × 16 radial) Electron Cyclotron Emission Imaging (ECEI) system in F-band (90-140 GHz) was installed on the EAST tokamak in 2012 to provide 2D electron temperature fluctuation images with high spatial and temporal resolution. A co-located Microwave Imaging Reflectometry (MIR) will be installed for imaging of density fluctuations by December 2016. This "4th generation" MIR system has eight independent frequency illumination beams in W-band (75-110 GHz) driven by fast tuning synthesizers and active multipliers. Both of these advanced millimeter-wave imaging diagnostic systems have applied the latest techniques. A novel design philosophy "general optics structure" has been employed for the design of the ECEI and MIR receiver optics with large aperture. The extended radial and poloidal coverage of ECEI on EAST is made possible by innovations in the design of front-end optics. The front-end optical structures of the two imaging diagnostics, ECEI and MIR, have been integrated into a compact system, including the ECEI receiver and MIR transmitter and receiver. Two imaging systems share the same mid-plane port for simultaneous, co-located 2D fluctuation measurements of electron density and temperature. An intelligent remote-control is utilized in the MIR electronics systems to maintain focusing at the desired radial region even with density variations by remotely tuning the probe frequencies in about 200 μs. A similar intelligent technique has also been applied on the ECEI IF system, with remote configuration of the attenuations for each channel.

  13. ECRH on ASDEX Upgrade - System Status, Feed-Back Control, Plasma Physics Results -

    Directory of Open Access Journals (Sweden)

    Flamm J.

    2012-09-01

    Full Text Available The ASDEX Upgrade (AUG ECRH system now delivers a total of 3.9 MW to the plasma at 140 GHz. Three new units are capable of 2-frequency operation and may heat the plasma alternatively with 2.1 MW at 105 GHz. The system is routinely used with X2, O2, and X3 schemes. For Bt = 3.2 T also an ITER-like O1-scheme can be run using 105 GHz. The new launchers are capable of fast poloidal movements necessary for real-time control of the location of power deposition. Here real-time control of NTMs is summarized, which requires a fast analysis of massive data streams (ECE and Mirnov correlation and extensive calculations (equilibria, ray-tracing. These were implemented at AUG using a modular concept of standardized real-time diagnostics. The new realtime capabilities have also been used during O2 heating to keep the first reflection of the non-absorbed beam fraction on the holographic reflector tile which ensures a well defined second pass of the beam through the central plasma. Sensors for the beam position are fast thermocouples at the edge of the reflector tile. The enhanced ECRH power was used for several physics studies related to the unique feature of pure electron heating without fueling and without momentum input. As an example the effect of the variation of the heating mix in moderately heated H-modes is demonstrated using the three available heating systems, i.e. ECRH, ICRH and NBI. Keeping the total input power constant, strong effects are seen on the rotation, but none on the pedestal parameters. Also global quantities as the stored energy are hardly modified. Still it is found that the central ion temperature drops as the ECRH fraction exceeds a certain threshold.

  14. EXPANDED VERY LARGE ARRAY OBSERVATIONS OF THE RADIO EVOLUTION OF SN 2011dh

    International Nuclear Information System (INIS)

    We report on Expanded Very Large Array observations of the Type IIb supernova 2011dh, performed over the first 100 days of its evolution and spanning 1-40 GHz in frequency. The radio emission is well described by the self-similar propagation of a spherical shockwave, generated as the supernova ejecta interact with the local circumstellar environment. Modeling this emission with a standard synchrotron self-absorption (SSA) model gives an average expansion velocity of v ≈ 0.1c, supporting the classification of the progenitor as a compact star (R* ≈ 1011 cm). We find that the circumstellar density is consistent with a ρ∝r–2 profile. We determine that the progenitor shed mass at a constant rate of ≈3 × 10–5 M☉ yr–1, assuming a wind velocity of 1000 km s–1 (values appropriate for a Wolf-Rayet star), or ≈7 × 10–7 M☉ yr–1 assuming 20 km s–1 (appropriate for a yellow supergiant [YSG] star). Both values of the mass-loss rate assume a converted fraction of kinetic to magnetic energy density of εB = 0.1. Although optical imaging shows the presence of a YSG, the rapid optical evolution and fast expansion argue that the progenitor is a more compact star—perhaps a companion to the YSG. Furthermore, the excellent agreement of the radio properties of SN 2011dh with the SSA model implies that any YSG companion is likely in a wide, non-interacting orbit.

  15. Microwave emission from high Arctic Sea ice during freeze-up

    Science.gov (United States)

    Hollinger, J. P.; Troy, B. E.; Ramseier, R. O.; Asmus, K. W.; Hartman, M. F.; Luther, C. A.

    1984-09-01

    A cooperative sea ice remote sensing experiment was conducted in the eastern Beaufort Sea and Mould Bay area during the freeze-up period in October 1981. Airborne millimeter-wave imagery at 90, 140, and 220 GHz, and nadir microwave radiometric measurements at 19, 22, and 31 GHz, were made from a U. S. Naval Research Laboratory aircraft, while the Canadian Atmospheric Environment Service conducted an extensive concurrent surface measurement program. This study demonstrates for the first time the high-resolution capability of 90 GHz to investigate detailed ice morphology and to define ice types. The 140 and 220 GHz imagery is the first ever made of sea ice at these high frequencies. Emissivities are determined for young ice, second-year ice (SY), multiyear ice (MY), new ice, old shorefast ice, and open water. The young ice exhibits the emissivity typical of first-year (FY) ice types, i.e., near unity and independent of frequency. The emissivities of new ice and open water increase with frequency, and that of MY ice decreases with frequency. Those of SY ice and old shorefast ice, measured here for the first time, also decrease with frequency but are larger in value than the MY emissivity. Ice type discrimination is optimum at 90 GHz, i.e., the spread in microwave signature between FY ice and old ice (SY and MY) is greatest at 90 GHz. The MY emissivity is lower than that of open water at both 90 and 140 GHz. The measurements presented here provide a basis for development of algorithms to exploit the potential of the Mission Sensor Microwave/Imager (SSM/I) to be launched on a Defense Meteorological Satellite in 1985 and, in particular, the 85.5-GHz SSM/I channels for ice type, concentration, and edge determination.

  16. Paramagnet induced signal quenching in MAS-DNP experiments in frozen homogeneous solutions

    Science.gov (United States)

    Corzilius, Björn; Andreas, Loren B.; Smith, Albert A.; Ni, Qing Zhe; Griffin, Robert G.

    2014-03-01

    The effects of nuclear signal quenching induced by the presence of a paramagnetic polarizing agent are documented for conditions used in magic angle spinning (MAS)-dynamic nuclear polarization (DNP) experiments on homogeneous solutions. In particular, we present a detailed analysis of three time constants: (1) the longitudinal build-up time constant TB for 1H; (2) the rotating frame relaxation time constant T1ρ for 1H and 13C and (3) T2 of 13C, the transverse relaxation time constant in the laboratory frame. These relaxation times were measured during microwave irradiation at a magnetic field of 5 T (140 GHz) as a function of the concentration of four polarizing agents: TOTAPOL, 4-amino-TEMPO, trityl (OX063), and Gd-DOTA and are compared to those obtained for a sample lacking paramagnetic doping. We also report the EPR relaxation time constants T1S and T2S, the DNP enhancements, ε, and the parameter E, defined below, which measures the sensitivity enhancement for the four polarizing agents as a function of the electron concentration. We observe substantial intensity losses (paramagnetic quenching) with all of the polarizing agents due to broadening mechanisms and cross relaxation during MAS. In particular, the monoradical trityl and biradical TOTAPOL induce ∼40% and 50% loss of signal intensity. In contrast there is little suppression of signal intensity in static samples containing these paramagnetic species. Despite the losses due to quenching, we find that all of the polarizing agents provide substantial gains in signal intensity with DNP, and in particular that the net enhancement is optimal for biradicals that operate with the cross effect. We discuss the possibility that much of this polarization loss can be regained with the development of instrumentation and methods to perform electron decoupling.

  17. Peculiar Velocity Constraints from Five-band SZ Effect Measurements toward RX J1347.5-1145 with MUSIC and Bolocam from the CSO

    Science.gov (United States)

    Sayers, Jack; Zemcov, Michael; Glenn, Jason; Golwala, Sunil R.; Maloney, Philip R.; Siegel, Seth R.; Wheeler, Jordan; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran P.; Gao, Jiansong; Hollister, Matthew I.; Lam, Albert; LeDuc, Henry G.; Mazin, Benjamin A.; McHugh, Sean G.; Miller, David A.; Mroczkowski, Tony K.; Noroozian, Omid; Nguyen, Hien T.; Radford, Simon J. E.; Schlaerth, James A.; Vayonakis, Anastasios; Wilson, Philip R.; Zmuidzinas, Jonas

    2016-04-01

    We present Sunyaev-Zel’dovich (SZ) effect measurements from wide-field images toward the galaxy cluster RX J1347.5-1145 obtained from the Caltech Submillimeter Observatory with the Multiwavelength Submillimeter Inductance Camera at 147, 213, 281, and 337 GHz and with Bolocam at 140 GHz. As part of our analysis, we have used higher frequency data from Herschel-SPIRE and previously published lower frequency radio data to subtract the signal from the brightest dusty star-forming galaxies behind RX J1347.5-1145 and from the AGN in RX J1347.5-1145’s BCG. Using these five-band SZ effect images, combined with X-ray spectroscopic measurements of the temperature of the intra-cluster medium (ICM) from Chandra, we constrain the ICM optical depth to be {τ }{{e}}={7.33}-0.97+0.96× {10}-3 and the ICM line of sight peculiar velocity to be {v}{pec}=-{1040}-840+870 km s-1. The errors for both quantities are limited by measurement noise rather than calibration uncertainties or astrophysical contamination, and significant improvements are possible with deeper observations. Our best-fit velocity is in good agreement with one previously published SZ effect analysis and in mild tension with the other, although some or all of that tension may be because that measurement samples a much smaller cluster volume. Furthermore, our best-fit optical depth implies a gas mass slightly larger than the Chandra-derived value, implying the cluster is elongated along the line of sight.

  18. Wills Plasma Physics Department annual report, 1989

    International Nuclear Information System (INIS)

    An overview of the collaborative researches carried out during the 1989 at the Wills Plasma Physics Department is given. The main activities included the study of hydromagnetic surface waves and RF heating using the Tortus tokamak; the development of diagnostic techniques, particularly those based on submillimetre lasers and tunable gyrotrons; gas discharge studies and investigations of apparent cold nuclear fusion in deuterated palladium. The small research tokamak Tortus was upgraded during the year, thus enabling the machine to be routinely and reliably operated at toroidal currents around 40 kA. A list of papers published or presented at various conferences during the year is included in the Appendix

  19. STAX. An Axion-like Particle Search with Microwave Photons

    CERN Document Server

    Ferretti, J

    2016-01-01

    We discuss an improved detection scheme for a light-shining-through-wall (LSW) experiment for axion-like particle searches. We propose to use: gyrotrons or klystrons, which can provide extremely intense photon fluxes at frequencies around 30 GHz; transition-edge-sensors (TES) single photon detectors in this frequency domain, with efficiency $\\approx1$; high quality factor Fabry-Perot cavities in the microwave domain, both on the photon-axion conversion and photon regeneration sides. We compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude for axion masses $\\lesssim 0.02$ meV.

  20. Spectral and variational principles of electromagnetic field excitation in wave guides

    Energy Technology Data Exchange (ETDEWEB)

    Yahalom, Asher [College of Judea and Samaria, Ariel 44284 (Israel)]. E-mail: asya@yosh.ac.il; Pinhasi, Yosef [College of Judea and Samaria, Ariel 44284 (Israel); Lurie, Yuri [College of Judea and Samaria, Ariel 44284 (Israel)

    2005-08-29

    Possible variational principles for excitation of an electromagnetic field in a wave guide are discussed. Our emphasis is not on the calculation of the modal shapes, which is common in previous art, but rather on the calculation of modal amplitude evolution, which are important in electron devices such as free electron lasers and gyrotrons. Variational principles have considerable importance in theoretical physics and are used among other things to derive numerical solution schemes, conservation laws via the Noether theorem and correct boundary conditions for the derived equations including the important effects of the backward waves amplitudes.

  1. Elmo Bumpy Torus proof of principle, Phase II: Title 1 report. Volume V. Vacuum-pumping system. Preliminary design report

    International Nuclear Information System (INIS)

    This report summarizes Title I Preliminary Design of the EBT-P Vacuum Pumping System. The Vacuum Pumping System has been designed by the McDonnell Douglas Astronautics Co. - St. Louis (MDAC). It includes the necessary vacuum pumps and vacuum valves to evacuate the torus, the Mirror Coil Dewars (MC Dewars), and the Gyrotron Magnet Dewars. The pumping ducts, manifolds, and microwave protection system are also included. A summary of the function of each subsystem and a description of its principle components is provided below. The analyses performed during the system design are also identified

  2. Infrared and millimeter waves v.14 millimeter components and techniques, pt.V

    CERN Document Server

    Button, Kenneth J

    1985-01-01

    Infrared and Millimeter Waves, Volume 14: Millimeter Components and Techniques, Part V is concerned with millimeter-wave guided propagation and integrated circuits. In addition to millimeter-wave planar integrated circuits and subsystems, this book covers transducer configurations and integrated-circuit techniques, antenna arrays, optoelectronic devices, and tunable gyrotrons. Millimeter-wave gallium arsenide (GaAs) IMPATT diodes are also discussed. This monograph is comprised of six chapters and begins with a description of millimeter-wave integrated-circuit transducers, focusing on vario

  3. Spectral and variational principles of electromagnetic field excitation in wave guides [rapid communication

    Science.gov (United States)

    Yahalom, Asher; Pinhasi, Yosef; Lurie, Yuri

    2005-08-01

    Possible variational principles for excitation of an electromagnetic field in a wave guide are discussed. Our emphasis is not on the calculation of the modal shapes, which is common in previous art, but rather on the calculation of modal amplitude evolution, which are important in electron devices such as free electron lasers and gyrotrons. Variational principles have considerable importance in theoretical physics and are used among other things to derive numerical solution schemes, conservation laws via the Noether theorem and correct boundary conditions for the derived equations including the important effects of the backward waves amplitudes.

  4. Millimeter wave technology IV and radio frequency power sources; Proceedings of the Meeting, Orlando, FL, May 21, 22, 1987

    Science.gov (United States)

    Wiltse, James C.; Coleman, James T.

    1987-01-01

    The present conference on mm-wave technology and radio-frequency power sources discusses topics in the fields of vacuum devices, mm-wave antennas and transmission lines, mm-wave systems and subsystems, and mm-wave techniques and components. Attention is given to recent experiments with planar orotrons, a high peak power X-band gyroklystron for linear supercolliders, cathode-driven crossed-field amplifiers, multi-MW quasi-optical gyrotrons, the radiation coupling of interinjection-locked oscillators, air-to-air mm-wave communications, mm-wave active and passive sensors for terrain mapping, and mm-wave components for electronically controllable antennas.

  5. A Dual-Beam Irradiation Facility for a Novel Hybrid Cancer Therapy

    CERN Document Server

    Sabchevski, Svilen; Ishiyama, Shintaro; Miyoshi, Norio; Tatsukawa, Toshiaki

    2012-01-01

    In this paper we present the main ideas and discuss both the feasibility and the conceptual design of a novel hybrid technique and equipment for an experimental cancer therapy based on the simultaneous and/or sequential application of two beams, namely a beam of neutrons and a CW (continuous wave) or intermittent sub-terahertz wave beam produced by a gyrotron for treatment of cancerous tumors. The main simulation tools for the development of the computer aided design (CAD) of the prospective experimental facility for clinical trials and study of such new medical technology are briefly reviewed. Some tasks for a further continuation of this feasibility analysis are formulated as well.

  6. Supplementary report: millimeter wave study program

    International Nuclear Information System (INIS)

    This report describes work done during the months of December 1975 and January 1976, following the writing of the final report on the millimeter wave study program for generation of 100 kW or more power at 120 GHz. The work has been directed to three areas for application to gyrotron devices, small signal analysis, electron beam simulation, and microwave measurements on cavity coupling. A small signal analysis is presented, which allows determination of beam loading in cavities. The results are similar to previous published work, but contain a higher order relativistic correction. The electron beam simulations include two magnetron type guns and one based on electrostatic lenses

  7. ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions

    Science.gov (United States)

    Stefan, V. Alexander

    2011-04-01

    Stimulated Raman scattering in the electron cyclotron frequency range of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay and Raman scattering is analyzed in reference to the bulk plasma heating. Supported in part by Nikola TESLA Labs, La Jolla, CA

  8. 29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

    Science.gov (United States)

    2010-07-01

    ...′ ir = 0.14 W', J); W = Tractor weight as specified by 29 CFR 1926.1002(e)(1) and (e)(3), in lb (W... provisions of 29 CFR 1926.1001 and 1926.1003 for rubber-tired dozers and rubber-tired loaders may be used... section. (4) For overhead protection requirements, see 29 CFR 1926.1003. (5) The following...

  9. Posidonia residues can be used as organic mulch and soil amendment for lettuce and tomato production

    OpenAIRE

    Grassi, Francesco; Mastrorilli, Marcello; Mininni, Carlo; Parente, Angelo; Santino, Angelo; Scarcella, Marcello; Santamaria, Pietro

    2015-01-01

    There is a need for sustainable fertilizers because common mineral fertilizers are increasingly costly and often induce water and air pollution. For instance, seagrass compost could be used as fertilizer in the coastal areas of the Mediterranean, thus also solving the issue of beached residues. Here, we studied organic fertilization by application of seagrass-based compost in a tomato and lettuce crop succession. Composts were made of posidonia and yard wastes at 1/4 w/w fresh weight ratio. C...

  10. Low Noise and Power Metamorphic HEMT Devices and Circuits with X=30% to 60% InxGaAs Channels on GaAs Substrates

    OpenAIRE

    Whelan, C.S.; Marsh, P.F.; Lardizabal, S.M.; Hoke, W.E.; McTaggart, R A; Kazior, T.E.

    2000-01-01

    Metamorphic HEMTs (MHEMTs) are becoming the device of choice for low cost millimeter-wave applications, where a high indium content channel is necessary for high performance. This paper will review the material properties, the processing, and the device and amplifier performance of metamorphic HEMTs with 30% to 60% indium channel content, with a focus on work done at Raytheon RF Components. 1.4W of output power at 44 GHz have been realized.

  11. Preparation and characterization of ethosomes for topical delivery of aceclofenac

    OpenAIRE

    Barupal A; Gupta Vandana; Ramteke Suman

    2010-01-01

    The aim of present study was to prepare and characterized ethosomes of aceclofenac which may deliver the drug to targeted site more efficiently than marketed gel preparation and also overcome the problems related with oral administration of drug. The formulations were prepared with varying the quantity of ethanol 10-50% (v/v), lecithin 1-4% (w/v), propylene glycol 5-20% (v/v) and evaluated for their vesicle size, shape and surface morphology, entrapment efficiency and in ...

  12. Photovoltaic OLED Driver for Low-Power Stand-Alone Light-to-Light Systems

    DEFF Research Database (Denmark)

    Ploug, Rasmus Overgaard; Knott, Arnold

    2016-01-01

    Photovoltaic (PV) stand-alone systems need to achieve multiple energy conversion modes. I.e. the energy conversion from PV to a local energy storage as well as energy conversion from the energy storage to the load. This paper documents the practical design considerations for the development...... conversion from photovoltaic panel to the battery, and 97 % in the area 1.4 W to 2 W for power delivery to the OLED....

  13. Ionization and fragmentation of C-60 via multiphoton-multiplasmon excitation

    OpenAIRE

    Hunsche, S; Starczewski, Tomas; L'Huillier, Anne; Persson, Anders; Wahlström, Claes-Göran; vandenHeuvell, B. V. L; Svanberg, Sune

    1996-01-01

    We study the intensity dependence of ionization and fragmentation of buckminsterfullerene (C-60) in strong laser fields. Our data provide strong evidence that at intensities less than or similar to 10(14) W/cm(2) these processes occur predominantly via multiphoton excitation of the 20 eV plasmon resonance of C-60 At least two plasmons have to be created to initiate fragmentation or multiple ionization.

  14. Absolute measurement of the ultrafast nonlinear electronic and rovibrational response in H$_2$ and D$_2$

    CERN Document Server

    Wahlstrand, J K; Cheng, Y -H; Palastro, J P; Milchberg, H M

    2015-01-01

    The electronic, rotational, and vibrational components of the ultrafast optical nonlinearity in H$_2$ and D$_2$ are measured directly and absolutely at intensities up to the ionization threshold of $\\sim$10$^{14}$ W/cm$^2$. As the most basic nonlinear interactions of the simplest molecules exposed to high fields, these results constitute a benchmark for high field laser-matter theory and simulation.

  15. Collision free generation of highly ionized atomic species with 193 nm radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luk, T.S.; Pummer, H.; Boyer, K.; Shahidi, M.; Egger, H.; Rhodes, C.K.

    1983-01-01

    The generation of highly ionized iodine (3+), xenon (5+), and mercury (4+) atoms at pressures of approx. 10/sup -6/ Torr and laser intensities of approx. 10/sup 14/ W/cm/sup 2/ at 193 nm is described. A minimum energy in excess of 170 eV, corresponding to greater than or equal to 27 photons, is required to produce Xe/sup 5 +/.

  16. Efficacy of a topically administered combination of emodepside and praziquantel against mature and immature Ancylostoma tubaeforme in domestic cats

    OpenAIRE

    Altreuther, G.; Borgsteede, F.H.M.; Buch, J; S.D. Charles; Cruthers, L.; Epe, C.; Young, D. R.; Krieger, K.J.

    2005-01-01

    This paper reports the efficacy of emodepside/praziquantel spot¿on (Profender®, Bayer AG, Leverkusen, Germany), a novel broadspectrum anthelmintic for dermal application, against L4 larvae and immature adult and adult stages of Ancylostoma tubaeforme in cats. The formulation contains 2.14% (w/w) emodepside and 8.58% (w/v) praziquantel, with emodepside being active against gastrointestinal nematodes and praziquantel against cestodes. Five randomized, blinded and controlled laboratory studies d...

  17. A scheme for a terahertz traveling-wave amplifier working with the TE11 mode in a circular waveguide

    International Nuclear Information System (INIS)

    To enlarge the interaction structure to a feasible dimension and to decrease the required magnetic field to an available strength, the gyrotron devices at THz frequencies must be designed with a high-order-mode interaction, which is weaker in a beam–wave interaction and more susceptible to mode competition. Using the same interaction structure (a circular waveguide) as in the gyrotron traveling-wave amplifier (gyro-TWT), but replacing the axial magnetic field of the gyro-TWT with a tapered helical magnetic field, we found that the gyrating electrons are able to perform strong interaction with the TE11 mode in the THz region. Through an example case, we explored the behavior of the particles and wave fields as in a beam–wave interaction under a modified scheme of the gyro-TWT with a numerical simulation code. The equations required for the simulation are presented. The simulation result of the example case indicates that, through the TE11 beam–wave interaction under the presented scheme, more than one quarter of the beam energy can be converted to the wave at 612.7 GHz and to heat, dissipated on the waveguide wall, of radius 2.5 cm

  18. High-efficiency wideband gyro-TWTs and gyro-BWOs with helically corrugated waveguides

    Science.gov (United States)

    Bratman, V. L.; Denisov, G. G.; Samsonov, S. V.; Cross, A. W.; Phelps, A. D. R.; Xe, W.

    2007-02-01

    We review the studies of gyrotron-type microwave devices whose electrodynamic system has the form of an oversized metal waveguide with a helically corrugated internal surface. For certain parameters, such a corrugation changes radically the waveguide dispersion ensuring an almost constant group velocity of the eigenmode for a small (close to zero) longitudinal wave number in a wide frequency band. The use of “helical” waveguides along with electron optical systems which form near-axis electron beams makes it possible to create high-efficiency amplifiers based on gyro-traveling-wave tubes (gyro-TWTs) with a wide instantaneous frequency band of amplification and gyro-backward-wave oscillators (gyro-BWOs) with continuous wideband tuning of the oscillation frequency. The studied devices are superior to the well-studied microwave sources of this type (gyroklystrons and gyrotrons) in frequency band, by more than an order of magnitude, and are not inferior to them in efficiency even for a wide spread of electron velocities.

  19. Linear Analysis of a Cyclotron Autoresonance Maser (CARM) Operating in a Transverse Magnetic Mode

    Science.gov (United States)

    Yang, Na; Zhang, Shi-Chang

    2009-04-01

    In the fast-wave devices like gyrotron, gyro-peniotron and cyclotron autoresonance maser (CARM) that generate millimeter and sub-millimeter waves, the transverse dimensions of the resonator and the output cylindrical waveguide become small. In order to prevent loss of electrons and thermal loading of the rf structure, the electron beam must be kept relatively far from the walls. The latter requirement demands smaller transverse dimensions of the helical electron beam as well. In this paper linear formulation of a CARM operating in a general transverse-magnetic (TM) mode is derived, and a detailed analysis of the influences of the parameters is presented for the TM1,1 mode CARM. It is found that, compared to the TE1,1 mode which is often employed in gyrotron traveling wave tube (gyro-TWT) and CARM experiments, the TM1,1 mode has a greater eigen value and consequently leads to a greater waveguide radius for a given cutoff wave number, and also, allows the electron beam to be settled close to the waveguide axis to have a small transverse dimension. Results show that a TM-mode CARM can reach high power and ultrahigh gain, just as a TE-mode CARM or a TE-mode gyro-TWT does.

  20. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

    Science.gov (United States)

    Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

  1. An overview of control system for the ITER electron cyclotron system

    International Nuclear Information System (INIS)

    The ITER electron cyclotron (EC) system having capability of up to 26 MW generated power at 170 GHz is being procured by 5 domestic agencies via 10 procurement arrangements. This implies diverse types of equipment and complex interface management. It also places a challenge on control system architecture to entertain the constraints of procurement slicing and meeting the overall functional requirement. The envisioned architecture is to use the local control units (supplied with each procurement) and a supervisory plant controller (by ITER). This offers a reliable control configuration for such delicate and complex EC plant system. The control system is envisioned to monitor the whole plant and perform automated tasks that are today performed via direct human intervention. For example, the automated gyrotron conditioning and active control of the EC plant to respond to requests from the plasma control system (PCS). This later aspect requires rapid shut down of the gyrotrons and power supplies, deviation of the actuators to direct the power from an equatorial to upper launcher and then restart of the power generation for rapid stabilization of the magneto hydrodynamic (MHD) instabilities that occur in high performance plasma operation. The plant controller will be designed for optimized performance with the PCS and the feedback control system used to actively control the power (with modulation capability up to 5 kHz) and launching direction for MHD stabilization.

  2. Investigation of the Millimeter-Wave Plasma Assisted CVD Reactor

    International Nuclear Information System (INIS)

    A polycrystalline diamond grown by the chemical vapor deposition (CVD) technique is recognized as a unique material for high power electronic devices owing to unrivaled combination of properties such as ultra-low microwave absorption, high thermal conductivity, high mechanical strength and chemical stability. Microwave vacuum windows for modern high power sources and transmission lines operating at the megawatt power level require high quality diamond disks with a diameter of several centimeters and a thickness of a few millimeters. The microwave plasma-assisted CVD technique exploited today to produce such disks has low deposition rate, which limits the availability of large size diamond disk windows. High-electron-density plasma generated by the millimeter-wave power was suggested for enhanced-growth-rate CVD. In this paper a general description of the 30 GHz gyrotron-based facility is presented. The output radiation of the gyrotron is converted into four wave-beams. Free localized plasma in the shape of a disk with diameter much larger than the wavelength of the radiation is formed in the intersection area of the wave-beams. The results of investigation of the plasma parameters, as well as the first results of diamond film deposition are presented. The prospects for commercially producing vacuum window diamond disks for high power microwave devices at much lower costs and processing times than currently available are outlined

  3. High-power millimeter-wave mode converters in overmoded circular waveguides using periodic wall perturbations

    International Nuclear Information System (INIS)

    This work reports on measurements and calculations (coupled mode equations) on the conversion of circular elecric TEsub(0n) gyrotron mode compositions (TE01 to TE04) at 28 and 70 GHz to the linearly polarized TE11 mode by means of a mode converter system using periodic waveguide wall perturbations. Mode transducers with axisymmetric radius perturbations transform the TEsub(0n) gyrotron mode mixture to the more convenient TE01 mode for long-distance transmission through overmoded waveguides. Proper matching of the phase differences between the TEsub(0n) modes and of lengths and perturbation amplitudes of the several converter sections is required. A mode converter with constant diameter and periodically perturbed curvature transfers the unpolarized TE01 mode into the TE11 mode which produces an almost linearly polarized millimeter-wave beam needed for efficient electron cyclotron heating (ECRH) of plasmas in thermonuclear fusion devices. The experimentally determined TEsub(0n)-to-TE01 conversion efficiency is (98+-1)% at 28 and 70 GHz (99% predicted) while the TE01-to-TE11 converter has a (96+-2)% conversion efficiency at 28 GHz (95% predicted) and (94+-2)% at 70 GHz (93% predicted); ohmic losses are included. (orig./AH)

  4. EU developments of the ITER ECRH system

    International Nuclear Information System (INIS)

    The EU will be providing the largest contribution to the ITER electron cyclotron (EC) heating and current drive (H and CD) system (20 MW, CW at 170 GHz). The contribution includes one third of the H and CD gyrotrons, their associated power supplies and four upper port launcher antennas. In all areas of participation, the EU EC partnership (coordinated by the European Fusion Development Agreement) aims toward advancing the technology, while staying within a specified cost envelope. This is portrayed in the co-axial gyrotron development that offers the potential to double the output power per source (2.0 MW), increasing the delivered power for a fixed number of auxiliary systems. The EU partnerships also attempt to increase performance for the entire EC system, in particular the launching antennas. The proposed front steering launcher design offers greater control of MHD activity than the previous remote steering design and opens up the possibility of an enhanced performance UL. The EC physics requirements are repartitioned between the upper and equatorial launchers for a synergetic balance, which increases the EC physics capabilities while relaxing some of the engineering requirements

  5. Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures

    Science.gov (United States)

    Matsuki, Yoh; Idehara, Toshitaka; Fukazawa, Jun; Fujiwara, Toshimichi

    2016-03-01

    Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0 90 K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395 GHz-600 MHz and 460 GHz-700 MHz DNP NMR spectrometers. The latter 700 MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T ∼100 K and ∼30 K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented.

  6. First experiments with gasdynamic ion source in CW mode

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga@ipfran.ru; Vodopyanov, A. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., Nizhny Novgorod 603950 (Russian Federation); Izotov, I.; Golubev, S. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., Nizhny Novgorod 603950 (Russian Federation); Tarvainen, O. [Department of Physics, University of Jyvaskyla, P.O. Box 35 (YFL), 40500 Jyvaskyla (Finland)

    2016-02-15

    A new type of ECR ion source—a gasdynamic ECR ion source—has been recently developed at the Institute of Applied Physics. The main advantages of such device are extremely high ion beam current with a current density up to 600–700 emA/cm{sup 2} in combination with low emittance, i.e., normalized RMS emittance below 0.1 π mm mrad. Previous investigations were carried out in pulsed operation with 37.5 or 75 GHz gyrotron radiation with power up to 100 kW at SMIS 37 experimental facility. The present work demonstrates the first experience of operating the gasdynamic ECR ion source in CW mode. A test bench of SMIS 24 facility has been developed at IAP RAS. 24 GHz radiation of CW gyrotron was used for plasma heating in a magnetic trap with simple mirror configuration. Initial studies of plasma parameters were performed. Ion beams with pulsed and CW high voltage were successfully extracted from the CW discharge. Obtained experimental results demonstrate that all advantages of the gasdynamic source can be realized also in CW operation.

  7. EBT-S 28-GHz, 200-kW, CW, mixed-mode, quasi-optical plasma heating system

    International Nuclear Information System (INIS)

    The ELMO Bumpy Torus-Scale (EBT-S) 28-GHz, 200-kW, cw, plasma heating system consists of a gyrotron oscillator, an oversized waveguide two-bend transmission system, and a quasi-optical mixed-mode microwave distribution manifold that feeds microwave power to the 24 plasma loads of the EBT-S fusion experiment. Balancing power to the 24 loads of the EBT-S fusion experiment. Balancing power to the 24 loads was achieved by adjusting the areas at 24 coupling irises. System performance is easily measured using system calorimetry. The distribution manifold mixed-mode power transmission, reflection, and loss coefficients are 89%, 6%, and 5%, respectively. The overall system efficiency (plasma power/gyrotron power) is 80%, but with some modifications to the distribution manifold we believe the ultimate efficiency can approach 90%. The system reliability is outstanding with a world's record 1 x 105 kW h of 28-GHz energy delivered to the EBT-S device with well over 1 x 103 operating hours

  8. Bragg Resonator Cyclotron Resonance Maser Experiments Driven by a Microsecond, Intense Electron Beam Accelerator

    Science.gov (United States)

    Choi, Jin Joo

    The cyclotron resonance maser (CRM) has proven to be attractive for many high power microwave applications such as fusion plasma heating, radar/communications, and high gradient RF accelerators. Most of the previous CRM experiments with MV electron beams have been conducted with short (gyrotron modes. Considerably less power from the TE_{11} gyro -BWO was observed for the Bragg resonator with ripples fully -outward. The microwave emission from the TE_ {21} absolute instability in the Bragg resonator with ripples fully-outward was successfully suppressed by lowering the cavity magnetic field. These three undesired oscillations, (TE _{21} absolute instability, TE _{11} gyro-BWO, TE _{51} second and third harmonic), were the most serious competing modes in the present Bragg resonator CRM experiments, apparently suppressing the TE _{31} CARM oscillation. For the Bragg resonator with ripples half-inward, we have performed gyrotron experiments with a high current electron beam. In these experiments, we have observed mode competition between the TE_{21 } absolute instability and the TE_ {11} gyro-BWO interaction by the use of frequency measurements and gas breakdown diagnostics.

  9. Final Report Advanced Quasioptical Launcher System

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Neilson

    2010-04-30

    This program developed an analytical design tool for designing antenna and mirror systems to convert whispering gallery RF modes to Gaussian or HE11 modes. Whispering gallery modes are generated by gyrotrons used for electron cyclotron heating of fusion plasmas in tokamaks. These modes cannot be easily transmitted and must be converted to free space or waveguide modes compatible with transmission line systems.This program improved the capability of SURF3D/LOT, which was initially developed in a previous SBIR program. This suite of codes revolutionized quasi-optical launcher design, and this code, or equivalent codes, are now used worldwide. This program added functionality to SURF3D/LOT to allow creating of more compact launcher and mirror systems and provide direct coupling to corrugated waveguide within the vacuum envelope of the gyrotron. Analysis was also extended to include full-wave analysis of mirror transmission line systems. The code includes a graphical user interface and is available for advanced design of launcher systems.

  10. Fast switching, modular high-voltage DC/AC-power supplies for RF-Amplifiers and other applications

    International Nuclear Information System (INIS)

    A new kind of high voltage high-power Pulse-Step Modulator (PSM) for broadcast transmitters, accelerator sources, for NBI (Neutral Beam Injection for Plasma Heating), gyrotrons and klystrons has been developed. Since its first introduction in 1984 for broadcast transmitters, more than 100 high-power sound broadcast transmitters had been equipped with the first generation of the PSM modulators, using Gate Turn-Off Thyristors (GTOs) as switching elements. Recently, due to faster switching elements and making use of the latest DSP technologies (Digital Signal Processing), the performance data and areas of application could be extended further. In 1994, a precision high voltage source for MW gyrotrons was installed at CRPP in Lausanne. Supplementary very low cost solutions for lower powers but high voltages had been developed. Hence, today, a large area of applications can be satisfied with the family of solutions. The paper describes the principle of operation, the related control systems and refers to some particular applications of the PSM amplifiers, especially the newest developments and corresponding field results

  11. Advanced Quasioptical Launcher System. Final Report

    International Nuclear Information System (INIS)

    This program developed an analytical design tool for designing antenna and mirror systems to convert whispering gallery RF modes to Gaussian or HE11 modes. Whispering gallery modes are generated by gyrotrons used for electron cyclotron heating of fusion plasmas in tokamaks. These modes cannot be easily transmitted and must be converted to free space or waveguide modes compatible with transmission line systems.This program improved the capability of SURF3D/LOT, which was initially developed in a previous SBIR program. This suite of codes revolutionized quasi-optical launcher design, and this code, or equivalent codes, are now used worldwide. This program added functionality to SURF3D/LOT to allow creating of more compact launcher and mirror systems and provide direct coupling to corrugated waveguide within the vacuum envelope of the gyrotron. Analysis was also extended to include full-wave analysis of mirror transmission line systems. The code includes a graphical user interface and is available for advanced design of launcher systems.

  12. Status of Europe’s contribution to the ITER EC system

    Directory of Open Access Journals (Sweden)

    Albajar F.

    2015-01-01

    Full Text Available The electron cyclotron (EC system of ITER for the initial configuration is designed to provide 20MW of RF power into the plasma during 3600s and a duty cycle of up to 25% for heating and (co and counter non-inductive current drive, also used to control the MHD plasma instabilities. The EC system is being procured by 5 domestic agencies plus the ITER Organization (IO. F4E has the largest fraction of the EC procurements, which includes 8 high voltage power supplies (HVPS, 6 gyrotrons, the ex-vessel waveguides (includes isolation valves and diamond windows for all launchers, 4 upper launchers and the main control system. F4E is working with IO to improve the overall design of the EC system by integrating consolidated technological advances, simplifying the interfaces, and doing global engineering analysis and assessments of EC heating and current drive physics and technology capabilities. Examples are the optimization of the HVPS and gyrotron requirements and performance relative to power modulation for MHD control, common qualification programs for diamond window procurements, assessment of the EC grounding system, and the optimization of the launcher steering angles for improved EC access. Here we provide an update on the status of Europe’s contribution to the ITER EC system, and a summary of the global activities underway by F4E in collaboration with IO for the optimization of the subsystems.

  13. Theoretical investigation of the competitive mechanism between dissociation and ionization of H₂⁺ in intense field.

    Science.gov (United States)

    Yao, Hongbin; Zhao, Guangjiu

    2014-10-01

    The competitive mechanism between dissociation and ionization of hydrogen molecular ion in intense field has been theoretically investigated by using an accurate non-Born-Oppenheimer method. The relative yield of fragments indicates that the dissociation and ionization channels are competitive with the increasing laser intensity from 5.0 × 10(13) to 2.0 × 10(14) W/cm(2). In the case of intensity lower than 1.0 × 10(14) W/cm(2), the dissociation channel is dominant, with a minor contribution from ionization. The mechanism of dissociation includes the contributions from the bond softening, bond hardening, below-threshold dissociation, and above-threshold dissociation, which are strongly dependent on the laser intensity and initial vibrational state. Furthermore, the ionization dominates over the dissociation channel at the highest intensity of 2.0 × 10(14) W/cm(2). The reasonable origin of ionization is ascribed as the above-threshold Coulomb explosion, which has been demonstrated by the space-time dependent ionization rate. Moreover, the competition mechanism between dissociation and ionization channels are displayed on the total kinetic energy resolved (KER) spectra, which could be tested at current experimental conditions.

  14. Protonated nanostructured aluminosilicate (NSAS reduces plasma cholesterol concentrations and atherosclerotic lesions in Apolipoprotein E deficient mice fed a high cholesterol and high fat diet

    Directory of Open Access Journals (Sweden)

    Constantinides Panayiotis P

    2009-07-01

    Full Text Available Abstract The aim of this work was to assess the effect of chronic administration of protonated nanostructured aluminosilicate (NSAS on the plasma cholesterol levels and development of atherosclerotic lesions in Apolipoprotein (ApoE deficient mice fed a high cholesterol and high fat diet. Apolipoprotein E (ApoE deficient mice were divided into the following treatment groups: protonated NSAS 1.4% (w/w, untreated control and 2% (w/w stigmastanol mixed with high-cholesterol/high-fat diet. Animals were treated for 12 weeks, blood samples were withdrawn every 4 weeks for determination of plasma cholesterol and triglyceride levels. At the end of the study the aortic roots were harvested for assessment of atherosclerotic lesions. NSAS at 1.4% (w/w and stigmastanol at 2% (w/w treatment groups showed significant decreases in plasma cholesterol concentrations at all time points relative to the control animals. The lesion sum area in 1.4% (w/w NSAS and 2% (w/w stigmastanol groups were significantly less from the control animals. In conclusion, in this study, the effectiveness of chronic administration of protonated NSAS material in the reduction of plasma cholesterol levels and decrease in development of atherosclerotic lesions was demonstrated in Apo-E deficient mice model.

  15. Effect of breast feeding time on physiological, immunological and microbial parameters of weaned piglets in an intensive breeding farm.

    Science.gov (United States)

    García, G R; Dogi, C A; Ashworth, G E; Berardo, D; Godoy, G; Cavaglieri, L R; de Moreno de LeBlanc, A; Greco, C R

    2016-08-01

    The aim of this work was to study the long-lasting consequences of different weaning age on physiological, immunological and microbiological parameters of weaned piglets. Piglets were weaned at 14 days (14W) or 21 days (21W). Blood samples were taken for IgG and cortisol determination on preweaning day and at 4; 20 and 40 post-weaning days. Three animals of each group were sacrificed. Small intestines for morphometric studies and secretory-IgA determination in fluid were taken. The cecum was obtained for enterobacteria, lactobacilli and total anaerobes enumeration. A significant decrease in piglet's plasma IgG concentrations was observed immediately after weaning and no differences were found between 14W and 21W. An increase in intestinal S-IgA was observed according to piglet's age. This increase was significantly higher in piglets 14W compared to piglets 21W. Animals from 14W group showed a decrease in villus length and in the number of goblet cells and intraepithelial lymphocytes. Other parameters were not affected by the weaning age. A short-term increase in cortisol was observed after weaning in both experimental groups. Enterobacteria decreased significantly after weaning in both groups, reaching values of weaning after 40 days. Lactobacilli counts decreased in both groups after weaning; however their counts were always higher than those obtained for enterobacteria. No differences were observed between 14W and 21W with regards to counts of anaerobes. The shortening of breast feeding time would favor an early synthesis of intestinal S-IgA after weaning. The changes observed in the microbiota could decrease postweaning enteric infections. However, early weaning induced negative effects on the cells of gut innate immunity and villi atrophy. This work provides knowledge about advantages and disadvantages at different weaning and long-lasting consequences on pig health. It is critical that swine producers become aware of the biological impacts of weaning age, so

  16. A MULTI-WAVELENGTH STUDY OF THE SUNYAEV-ZEL'DOVICH EFFECT IN THE TRIPLE-MERGER CLUSTER MACS J0717.5+3745 WITH MUSTANG AND BOLOCAM

    Energy Technology Data Exchange (ETDEWEB)

    Mroczkowski, Tony; Korngut, Phillip; Bock, James; Zemcov, Michael [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Dicker, Simon; Reese, Erik D.; Young, Alexander; Devlin, Mark [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Sayers, Jack; Czakon, Nicole; Golwala, Sunil [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Mason, Brian; Romero, Charles [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Sarazin, Craig [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22901 (United States); Koch, Patrick M.; Lin, Kai-Yang; Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P. O. Box 23-141, Taipei 10617, Taiwan (China); Molnar, Sandor M. [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China); Pierpaoli, Elena, E-mail: tonym@astro.caltech.edu [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089 (United States)

    2012-12-10

    We present 90, 140, and 268 GHz subarcminute resolution imaging of the Sunyaev-Zel'dovich effect (SZE) in the disturbed, intermediate-redshift (z 0.5458) galaxy cluster MACS J0717.5+3745, a triple-merger system comprising four distinct, optically detected subclusters. Our 90 GHz SZE data result in a sensitive, 34 {mu}Jy beam{sup -1} map of the SZE at 13'' effective resolution using the MUSTANG bolometer array on the Green Bank Telescope (GBT). Our 140 and 268 GHz SZE imaging, with resolutions of 58'' and 31'' and sensitivities of 1.8 and 3.3 mJy beam{sup -1}, respectively, was obtained through observations from the Caltech Submillimeter Observatory using Bolocam. We compare these maps to a two-dimensional pressure map derived from Chandra X-ray observations. Our MUSTANG SZE data confirm previous indications from Chandra of a pressure enhancement due to shock-heated, {approx}> 20 keV gas immediately adjacent to extended radio emission seen in low-frequency radio maps of this cluster. MUSTANG also detects pressure substructure that is not well constrained by the Chandra X-ray data in the remnant core of a merging subcluster. We find that the small-scale pressure enhancements in the MUSTANG data amount to {approx}2% of the total pressure measured in the 140 GHz Bolocam observations. The X-ray inferred pseudo-pressure template also fails on larger scales to accurately describe the Bolocam data, particularly at the location of the subcluster with a remnant core known to have a high line-of-sight optical velocity of {approx}3200 km s{sup -1}. Our Bolocam data are adequately described when we add an additional component-not described by a thermal SZE spectrum-to the X-ray template coincident with this subcluster. Using flux densities extracted from our model fits, and marginalizing over the X-ray spectroscopic temperature constraints for the region, we fit a thermal + kinetic SZE spectrum to our Bolocam data and find that the subcluster

  17. Development of high power windows for ECH(and)CD launchers

    International Nuclear Information System (INIS)

    Electron Cyclotron Heating and Current Drive (ECH(and)CD) systems are a major part of nuclear fusion technology as localised and steerable deposition of high power mm-waves contributes essentially to plasma start-up, plasma heating, shaping of current profiles, and plasma stabilisation. At ITER, the first tritium confinement in the mm-wave launchers will be formed by CVD diamond windows. Based on large area CVD diamond disks and their unparalleled combination of ultralow mm-wave absorption and outstanding thermal conductivity, the window design for front steering (FS) and remote steering (RS) launchers was worked out for a transmission capability of 2 MW at the fixed frequency of 170 GHz. In addition, a torus window was designed for a step-tuneable Electron Cyclotron wave system for ASDEX Upgrade for transmission of up to 1 MW mm-wave power at 4 selected frequencies between 105 - 140 GHz. The designs for the torus windows for the three different launcher concepts account for the specific transmission requirements. For single-frequency operation, a single disk configuration was established. The disk thickness is adapted to provide sufficient safety margin towards pressure rise in the vacuum vessel (0.2 MPa) for the required window aperture. For the RS launcher, the remote steering unit placed in the back-end of the launcher requires a large window aperture (95 mm) to avoid beam vignetting at the extreme steering angles of ±12 o. For the FS launcher with the steering mechanism placed in the front shield of the launcher, the disk size is reduced as the window aperture can be identical to the waveguide inner diameter (63.5 mm). This allows to consider indirect cooling instead of edge cooling and thus to eliminate the risk of tritium contact to the cooling water in case of crack formation in the diamond disk. For the multi-frequency torus window at ASDEX-Upgrade a double disk configuration with the disk separation of 5 mm, fine tuneable over ± 1 mm, is realised. The

  18. AlGaN/GaN-based HEMT on SiC substrate for microwave characteristics using different passivation layers

    Indian Academy of Sciences (India)

    T R Lenka; A K Panda

    2012-07-01

    In this paper, a new gate-recessed AlGaN/GaN-based high electron mobility transistor (HEMT) on SiC substrate is proposed and its DC as well as microwave characteristics are discussed for Si3N4 and SiO2 passivation layers using technology computer aided design (TCAD). THe two-dimensional electron gas (2DEG) transport properties are discussed by solving Schödinger and Poison equations self-consistently resulting in various subbands having electron eigenvalues. From DC characteristics, the saturation drain currents are measured to be 600 mA/mm and 550 mA/mm for Si3N4 and SiO2 passivation layers respectively. Apart from DC, small-signal AC analysis has been done using two-port network for various microwwave parameters. The extrinsic transconductance parameters are measured to be 131.7 mS/mm at a gate voltage of $V_{gs} = -0.35$ V and 114.6 mS/mm at a gate voltage of $V_{gs} = -0.4$ V for Si3N4 and SiO2 passivation layers respectively. The current gain cut-off frequencies $(f_{t})$ are measured t be 27.1 GHz and 23.97 GHz in unit-gain-point method at a gate voltage of -0.4 V for Si3N4 and SiO2 passivation layers respectively. Similarly, the power gain cut-off frequencied $(f_{max})$ are measured to be 41 GHz and 38.5 GHz in unit-gain-point method at a gate voltage of -0.1 V for Si3N4 and SiO2 passivation layers respectively. Furthermore, the maximum frequency of oscillation or unit power gain (MUG = 1) cut-off frequencies for Si3N4 and SiO2 passivation layers are measured to be 32 GHz and 28 GHz respectively from MUG curves and the unit current gain, $|h_{21}| = 1$ cut-off frequencies are measured to be 140 GHz and 75 GHz for Si3N4 and SiO2 passivation layers respectively from the $abs |h_{21}|$ curves. HEMT with Si3N4 passivation layer giver better results than HEMT with SiO2 passivation layer.

  19. Construction of an integrated down-converter for operation at 200 GHz

    International Nuclear Information System (INIS)

    There is currently considerable interest in the part of the electromagnetic spectrum known as the terahertz region (100 GHz to 10 THz). Traditionally, terahertz radiation was the preserve of specialist applications in astronomy, atmospheric studies and plasma diagnostics. However, potential or actual applications in such diverse fields as medicine, security, communications and military applications are now emerging. At present there are very few devices and systems that operate in this spectral region and those which exist are expensive and difficult to manufacture. For the potential of terahertz radiation to be realised by industry, a low-cost (i.e. 'manufacturable') method of constructing terahertz systems is needed; new methods of generating radiation at terahertz frequencies are also urgently required. This thesis presents the development of a novel technique for producing passive and active devices and systems for use at terahertz frequencies. This novel approach utilises standard semiconductor techniques to fabricate metal-pipe waveguides directly onto semiconductor wafers. As standard semiconductor techniques are used, it provides a possible low-cost and highly manufacturable method of producing terahertz devices and systems. The key processes that are needed to produce components and devices for terahertz systems have been developed and presented in this work. Metal-pipe rectangular waveguides for use at W-band (70 GHz - 110 GHz) and G-band (140 GHz - 220 GHz) have been fabricated and S-parameter measurements have been performed on them using a specially designed test fixture. The measured attenuation for these waveguides is approximately 0.2 dB to 5 dB per guide wavelength for W-band and 0.6 dB per guide wavelength for G-band; these results suggest that these components could be used in practical systems. A method of interfacing with terahertz systems and free-space is needed in real applications, so a horn antenna has been designed which can be

  20. Experimental Study of an ion cyclon resonance accelerator presentation of his thesis

    CERN Document Server

    Ramsell, C T

    1999-01-01

    The Ion Cyclotron Resonance Accelerator (ICRA) uses the operating principles of cyclotrons and gyrotrons. The novel geometry of the ICRA allows an ion beam to drift axially while being accelerated in the azimuthal direction. Previous work on electron cyclotron resonance acceleration used waveguide modes to accelerate an electron beam [5]. This research extends cyclotron resonance acceleration to ions by using a high field superconducting magnet and an rf driven magnetron operating at a harmonic of the cyclotron frequency. The superconducting solenoid provides an axial magnetic field for radial confinement and an rf driven magnetron provides azimuthal electric fields for acceleration. The intent of the ICRA concept is to create an ion accelerator which is simple, compact, lightweight, and inexpensive. Furthermore, injection and extraction are inherently simple since the beam drifts through the acceleration region. However, use of this convenient geometry leads to an accelerated beam with a large energy spread....

  1. One THz. Beamed Energy - Mission Capabilities

    Science.gov (United States)

    Johansen, Donald G.

    2005-04-01

    Gyrotrons now used for nuclear fusion experiments are a possibile source for beamed energy electro-thermal propulsion. Water vapor absorption is likely to bar 1 THz. transmission through the atmosphere. A space-based source in low equatorial orbit offers beamed energy velocity increments for upper stage orbit insertion. Transfer orbits to geosynchronous and lunar destinations and escape velocities to Mars and Venus are considered. Rapid acceleration (1 g) at high specific impulse implies very high source power and mass. Altitudes for BEP source satellites are in 600 to 800 kilometer range, set by atmospheric drag and avoidance of van Allen belt. Earth oblateness plus lunar and solar tidal forces are important factors governing source orbit selection and maintenance.

  2. Status of the ITER Electron Cyclotron Heating and Current Drive System

    Science.gov (United States)

    Darbos, Caroline; Albajar, Ferran; Bonicelli, Tullio; Carannante, Giuseppe; Cavinato, Mario; Cismondi, Fabio; Denisov, Grigory; Farina, Daniela; Gagliardi, Mario; Gandini, Franco; Gassmann, Thibault; Goodman, Timothy; Hanson, Gregory; Henderson, Mark A.; Kajiwara, Ken; McElhaney, Karen; Nousiainen, Risto; Oda, Yasuhisa; Omori, Toshimichi; Oustinov, Alexander; Parmar, Darshankumar; Popov, Vladimir L.; Purohit, Dharmesh; Rao, Shambhu Laxmikanth; Rasmussen, David; Rathod, Vipal; Ronden, Dennis M. S.; Saibene, Gabriella; Sakamoto, Keishi; Sartori, Filippo; Scherer, Theo; Singh, Narinder Pal; Strauß, Dirk; Takahashi, Koji

    2016-01-01

    The electron cyclotron (EC) heating and current drive (H&CD) system developed for the ITER is made of 12 sets of high-voltage power supplies feeding 24 gyrotrons connected through 24 transmission lines (TL), to five launchers, four located in upper ports and one at the equatorial level. Nearly all procurements are in-kind, following general ITER philosophy, and will come from Europe, India, Japan, Russia and the USA. The full system is designed to couple to the plasma 20 MW among the 24 MW generated power, at the frequency of 170 GHz, for various physics applications such as plasma start-up, central H&CD and magnetohydrodynamic (MHD) activity control. The design takes present day technology and extends toward high-power continuous operation, which represents a large step forward as compared to the present state of the art. The ITER EC system will be a stepping stone to future EC systems for DEMO and beyond.

  3. Destabilization of fast particle stabilized sawteeth in ASDEX Upgrade with electron cyclotron current drive

    DEFF Research Database (Denmark)

    Igochine, V.; Chapman, I.T.; Bobkov, V.;

    2011-01-01

    Upgrade for destabilization of fast particle stabilized sawteeth with electron cyclotron current drive (ECCD). It is shown that moderate ECCD from a single gyrotron is able to destabilize the fast particle stabilized sawteeth. A reduction in sawtooth period by about 40% was achieved in first experiments......It is often observed that large sawteeth trigger the neoclassical tearing mode well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX....... These results show that ECCD can be used as a tool for control of sawteeth also in the presence of fast particles....

  4. Large Scale CW ECRH Systems: Some considerations

    Directory of Open Access Journals (Sweden)

    Turkin Y.

    2012-09-01

    Full Text Available Electron Cyclotron Resonance Heating (ECRH is a key component in the heating arsenal for the next step fusion devices like W7-X and ITER. These devices are equipped with superconducting coils and are designed to operate steady state. ECRH must thus operate in CW-mode with a large flexibility to comply with various physics demands such as plasma start-up, heating and current drive, as well as configurationand MHD - control. The request for many different sophisticated applications results in a growing complexity, which is in conflict with the request for high availability, reliability, and maintainability. ‘Advanced’ ECRH-systems must, therefore, comply with both the complex physics demands and operational robustness and reliability. The W7-X ECRH system is the first CW- facility of an ITER relevant size and is used as a test bed for advanced components. Proposals for future developments are presented together with improvements of gyrotrons, transmission components and launchers.

  5. Applications of ECH on the DIII-D tokamak and projections for future ECH upgrades

    Directory of Open Access Journals (Sweden)

    Solomon W.M.

    2012-09-01

    Full Text Available Electron Cyclotron Heating and Current Drive plays an important role in the DIII-D program. In high performance discharges EC power contributes greatly to MHD stability, and this is particularly important for discharges with low rotational torque applied, as will be the case for ITER. Off-axis EC current drive also plays a key role in the actualization of steady-state scenarios by supporting the desired current profile. In order to carry out these applications at higher beta and higher field, an upgrade of the EC power to 15 MW is needed, and the best gyrotron frequency for the DIII-D program is 117.5 GHz.

  6. Performance measurements of the collective Thomson scattering receiver at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Furtula, Vedran; Leipold, Frank; Salewski, Mirko;

    2012-01-01

    The fast-ion collective Thomson scattering (CTS) receiver at ASDEX Upgrade can detect spectral power densities of a few eV in the millimeter-wave range against the electron cyclotron emission (ECE) background on the order of 100 eV under presence of gyrotron stray radiation that is several orders...... detector diodes. The performance of the entire receiver is determined by the main receiver components operating at mm-wave frequencies (notch-, bandpass- and lowpass filters, a voltage-controlled variable attenuator, and an isolator), a mixer, and the IF components (amplifiers, band-pass filters......, and detector diodes). We discuss here the design of the entire receiver, focussing on its performance as a unit. The receiver has been disassembled, and the performance of its individual components has been characterized. Based on these individual component measurements we predict the spectral response...

  7. Kinetic instabilities in a mirror-confined ECR discharge plasma

    Science.gov (United States)

    Mansfeld, Dmitry; Viktorov, Mikhail; Vodopyanov, Alexander; Golubev, Sergey

    2015-11-01

    Kinetic instabilities of nonequilibrium plasma heated by powerful radiation of gyrotron in electron cyclotron resonance conditions and confined in a mirror magnetic trap are reported. Instabilities are manifested as the generation of short pulses of electromagnetic radiation accompanied by precipitation of hot electrons from magnetic trap. Measuring electromagnetic field with high temporal resolution allowed to observe various dynamic spectra of electromagnetic radiation related to at least five types of kinetic instabilities. The opportunity to recreate different conditions for excitation and amplification of waves in plasma in a single ECR discharge pulse has been demonstrated. This report may be of interest in the context of a laboratory modeling of nonstationary wave-particle interaction processes in nonequilibrium space plasma since the observed phenomena have much in common with similar processes occurring in the magnetosphere of the Earth, planets, and in solar coronal loops. Work was supported by Russian Foundation for Basic Research # 15-32-20770.

  8. Instability of field-aligned electron-cyclotron waves in a magnetic mirror plasma with anisotropic temperature

    Science.gov (United States)

    Grishanov, N. I.; Azarenkov, N. A.

    2016-08-01

    > Dispersion characteristics have been analysed for field-aligned electron-cyclotron waves (also known as right-hand polarized waves, extraordinary waves or whistlers) in a cylindrical magnetic mirror plasma including electrons with anisotropic temperature. It is shown that the instability of these waves is possible only in the range below the minimal electron-cyclotron frequency, which is much lower than the gyrotron frequency used for electron-cyclotron resonance power input into the plasma, under the condition where the perpendicular temperature of the resonant electrons is larger than their parallel temperature. The growth rates of whistler instability in the two magnetized plasma models, where the stationary magnetic field is either uniform or has a non-uniform magnetic mirror configuration, are compared.

  9. Tokamak research in the Soviet Union

    International Nuclear Information System (INIS)

    Important milestones on the way to the tokamak fusion reactor are recapitulated. Soviet tokamak research concentrated at the I.V. Kurchatov Institute in Moscow, the A.F. Ioffe Institute in Leningrad and the Physical-Technical Institute in Sukhumi successfully provides necessary scientific and technological data for reactor design. Achievments include, the successful operation of the first tokamak with superconducting windings (T-7) and the gyrotron set for microwave plasma heating in the T-10 tokamak. The following problems have intensively been studied: Various methods of additional plasma heating, heat and particle transport, and impurity control. The efficiency of electron-cyclotron resonance heating was demonstrated. In the Joule heating regime, both the heat conduction and diffusion rates are anomalously high, but the electron heat conduction rate decreases with increasing plasma density. Progress in impurity control makes it possible to obtain a plasma with effective charge approaching unity. (J.U.)

  10. 36th Annual International Conference on Infrared Millimeter and Terahertz Waves

    Energy Technology Data Exchange (ETDEWEB)

    Mittleman, Daniel M. [Rice University

    2011-12-31

    The Major Topic List of the 2011 conference featured a category entitled “IR, millimeter-wave, and THz spectroscopy,” another entitled “Gyro-Oscillators and Amplifiers, Plasma Diagnostics,” and a third called “Free Electron Lasers and Synchrotron Radiation.” Topical areas of interest to meeting participants include millimeter-wave electronics, high-power sources, high-frequency communications systems, and terahertz sensing and imaging, all of which are prominent in the research portfolios of the DOE. The development and study of new materials, components, and systems for use in the IR, THz, and MMW regions of the spectrum are of significant interest as well. a series of technical sessions were organized on the following topics: terahertz metamaterials and plasmonics; imaging techniques and applications; graphene spectroscopy; waveguide concepts; gyrotron science and technology; ultrafast terahertz measurements; and quantum cascade lasers.

  11. Massachusetts Institute of Technology, Plasma Fusion Center, technical research programs

    Energy Technology Data Exchange (ETDEWEB)

    1982-02-01

    Research programs have produced significant results on four fronts: (1) the basic physics of high-temperature fusion plasmas (plasma theory, RF heating, development of advanced diagnostics and small-scale experiments on the Versator tokamak and Constance mirror devices); (2) major confinement results on the Alcator A and C tokamaks, including pioneering investigations of the equilibrium, stability, transport and radiation properties of fusion plasmas at high densities, temperatures and magnetic fields; (3) development of a new and innovative design for axisymmetric tandem mirrors with inboard thermal barriers, with initial operation of the TARA tandem mirror experimental facility scheduled for 1983; and (4) a broadly based program of fusion technology and engineering development that addresses problems in several critical subsystem areas (e.g., magnet systems, superconducting materials development, environmental and safety studies, advanced gyrotron development for RF heating, preconceptual design studies of torsatrons and stellarators, and advanced tokamak design and reactor studies).

  12. Synthesis and Characterization of Microwave Sintered Silica Xerogel Produced from Rice Husk Ash

    Science.gov (United States)

    Sudiana, I. N.; Mitsudo, S.; Nishiwaki, T.; Susilowati, P. E.; Lestari, L.; Firihu, M. Z.; Aripin, H.

    2016-08-01

    Silica xerogel ceramic produced from rice husk ash (RHA) taken from South East Sulawesi Indonesia has been successfully sintered by using a millimeter waves (MMW) heating system with a 28 GHz gyrotron as radiation source. The ceramic was also sintered by using an electric furnace where served as a comparison. Densification, microstructural, and morphological characterization of the silica were then investigated by using an Archimedes densification measurement method device, a X-ray diffraction (XRD) and a Scanning Electron Microscopy (SEM), respectively. Effect of microwave energy on the properties of silica xerogel ceramic were evaluated and discussed and compared to conventionally sintered results. The notably different densification and microstructure of sintered samples after sintering were found. The results suggest that microwave radiation provides a microwave effect during sintering.

  13. Application of high power microwave vacuum electron devices

    International Nuclear Information System (INIS)

    High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

  14. Destabilization of fast particle stabilized sawteeth in ASDEX Upgrade with electron cyclotron current drive

    Energy Technology Data Exchange (ETDEWEB)

    Igochine, V; Bobkov, V; Guenter, S; Maraschek, M; Pereversev, G; Reich, M; Stober, J [MPI fuer Plasmaphysik, Euratom-Association, D-85748 Garching (Germany); Chapman, I T [EURATOM/CCFE Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Moseev, D, E-mail: valentin.igochine@ipp.mpg.de [EURATOM-Risoe DTU, Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark)

    2011-02-15

    It is often observed that large sawteeth trigger the neoclassical tearing mode well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX Upgrade for destabilization of fast particle stabilized sawteeth with electron cyclotron current drive (ECCD). It is shown that moderate ECCD from a single gyrotron is able to destabilize the fast particle stabilized sawteeth. A reduction in sawtooth period by about 40% was achieved in first experiments. These results show that ECCD can be used as a tool for control of sawteeth also in the presence of fast particles. (brief communication)

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

    Energy Technology Data Exchange (ETDEWEB)

    S.G.E. Pronko; D.S. Baggest

    1999-12-01

    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.

  16. Principle of Terahertz Radiation Using Electron Beams

    Science.gov (United States)

    Shin, Young-Min; Choi, Eun-Mi; Park, Gun-Sik

    This part introduces high power THz coherent radiation sources that take advantage of free electron beams. Following a description of characteristics on vacuum electron devices (VEDs), fundamental radiation principle of beam-wave interaction is explained with specifying their types and applications. Conventional high power microwave VEDs such as klystrons, TWTs, gyrotrons, and FELs are described in their technical perspectives with brief overview of device characteristics. Addressing technical challenges on up-conversion-to-THz of conventional approach, this part explores the state-of-the-art micro-VEDs considered for modern THz applications such as communication, imaging, sensing, spectroscopy, and so on, which are combined with modern microfabrication technologies. Novel MEMS techniques to microminiaturize RF components such as electron gun and RF interaction circuits are also presented.

  17. Space Experiments to Advance Beamed Energy Propulsion

    Science.gov (United States)

    Johansen, Donald G.

    2010-05-01

    High power microwave sources are now available and usable, with modification, or beamed energy propulsion experiments in space. As output windows and vacuum seals are not needed space is a natural environment for high power vacuum tubes. Application to space therefore improves reliability and performance but complicates testing and qualification. Low power communications satellite devices (TWT, etc) have already been through the adapt-to-space design cycle and this history is a useful pathway for high power devices such as gyrotrons. In this paper, space experiments are described for low earth orbit (LEO) and lunar environment. These experiments are precursors to space application for beamed energy propulsion using high power microwaves. Power generation and storage using cryogenic systems are important elements of BEP systems and also have an important role as part of BEP experiments in the space environment.

  18. TWTs and klystrons for satellite relay telecommunications systems

    Science.gov (United States)

    Pujes, J. P.

    Earth-station power amplifiers can be equipped with either klystrons or TWTs. Improvements in the field of klystrons has been continuous but not spectacular. Brazed-helix technology enables broadband helix TWTs to operate at high power levels. A 1.5-kW, 6-GHz brazed-helix TWT has achieved an average operating life of 15,000 hours. A 3-kW, 6-GHz tube is being developed, as well as 160-W and 750-W 14-GHz tubes. Coupled-cavity power TWTs are still used at frequencies of 14 GHz and higher. A 1-kW, 30-GHz TWT is being prepared. In the future, gyrotrons might be used at frequencies higher than 30 GHz.

  19. Interest in MM waves spurs tube growth

    Science.gov (United States)

    Acker, A. E.

    1982-07-01

    Military demand is growing for new components which can be used in advanced radar, electronic counter-measures, and communications equipment. Unfortunately, the techniques used in building microwave tubes for lower frequencies cannot be translated easily to millimeter-wave-length components. Thus, designers must come up with new techniques, new materials, and most importantly, new circuit forms which will provide the required performance while allowing the components to be manufactured at reasonable cost and production rates. Attention is given to requirements for permanent magnets, periodic permanent magnets, traveling-wave tubes, millimeter-wave klystrons, extended interaction amplifiers, the use of space-harmonic and non-space-harmonic traveling-wave tubes for applications requiring bandwidths in excess of several hundred MHz, Gyrotron size advantages, cathode loading problems, and future requirements.

  20. Analysis of the electron cyclotron maser instability

    Science.gov (United States)

    Kuo, S. P.; Cheo, B. R.

    1984-07-01

    The nonlinear evolution of the electron cyclotron maser instability is investigated analytically, with a focus on the saturation due to phase trapping of gyrating particles in the wave. The equations of motion of a single electron moving in the wave are solved; the collective response of electrons to wave fields is obtained by averaging over the initial random phase distribution; and a single nonlinear equation governing the time evolution of the amplitude is derived self-consistently. Numerical results are presented in graphs and shown to be in good agreement with those of a particle simulation, at a significant savings in computational effort. The results are applicable to the improvement of high-power gyrotron-type mm and sub-mm emitters for radar communications or plasma heating in controlled-fusion devices.

  1. Infrared and millimeter waves. Volume 14 - Millimeter components and techniques. Part 5

    Science.gov (United States)

    Button, K. J.

    Experimental, theoretical and design efforts for millimeter-wave (mm-wave) propagation and integrated circuits (ICs) are discussed in depth. This volume includes contributions on mm-wave IC transducers and planar ICs and subsystems. Various design and analytical approaches taken to produce mm-wave planar antenna arrays are described, along with experimental work on optoelectronic devices to generating mm waves. Analytical tools are defined for investigating mm-wave GaAs IMPATT diodes and evaluating their thermal performance, reliability, and device-circuit interaction properties. Finally, theoretical and experimental results with several prototype low power tunable gyrotrons being developed as coherent millimeter-submillimeter radiation sources are discussed. Low-cost, mass producible solid-state mm-wave devices are being investigated as radiation sources for absorption spectroscopy of materials and radar and communications applications.

  2. SMIS75金属离子的多重电离%Multiple Ionization of Metal Ions in SMIS 75

    Institute of Scientific and Technical Information of China (English)

    A.V.Vodopyanov; S.V.Golubev; V.I.Khizhnyak; D.A.Mansfeld; A.G.Nikolaev; E.M.Oks; G.Yu.Yushkov

    2007-01-01

    A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T.variable length 15-20cm and mirror ratio 3-5.The plasma of metal ions is injected into the trap by a special vacuum arc minigun.Plasma heating is performed by the microwave radiation of a gyrotron(the frequency of 75GHz,power up to 200kW,pulse duration up to 150μs).The results of the experiment have demonstrated substantial multiple ionization of metal ions.For a metal with high melting temperature(Pt),heating shifts the average ion charge from Pt2+ up to Pt7+.Maximum stripped observed ion is Pt10+.Total current of ion beam is about 300mA.

  3. Quasi-Optical Transmission Lines for ECRH on TJ-II Stellarator

    International Nuclear Information System (INIS)

    Two mirror lines are used to transmit ht microwave power from the powerful microwave generators to the TJ-II plasmas. Both lines have been tested at nominal power level and they are now in operation. This paper is devoted to the final design of the transmission lines and their testing. Before starting operation at high power level measurements of the wave beam parameters at low power level were made. Two horn antennae were designed to simulate the gyrotron output. Numerical simulations of the far field radiation pattern of the antennae were made, a computer code based on Huygens diffraction theory was developed to simulate the propagation of the beam along a mirror line. A comparison of the theoretical and the experimental results is also presented here. (Author)

  4. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Directory of Open Access Journals (Sweden)

    Shimozuma T.

    2015-01-01

    Full Text Available In a high power Electron Cyclotron Resonance Heating (ECRH system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  5. Cold Testing Of A Radial Extraction Output Cavity For A Frequency-doubling Gyroklystron

    CERN Document Server

    Bharathan, K

    2004-01-01

    Research in the University of Maryland Gyroklystron program has centered around the development of a 17.136 GHz gyroklystron, that combines the gyrotron mechanism with the ballistic bunching of klystrons to produce a high power, high gain amplifier. The current tube is a 4- cavity (input, buncher, penultimate and output) coaxial, frequency doubling system that will be used as a driver for the Haimson Research Corporation (HRC) accelerator structure. This thesis presents the design, simulation, optimization, cold test methodology and performance data of a proposed radial extraction output cavity in which the microwave energy is extracted through an inner coaxial conductor in the TE01 circular mode. The positioning of dielectrics in the drift spaces and the effect of axial and radial misalignments between the inner and outer walls of the cavity were studied at depth and quantified. One advantage of this topology is that it reduces the size and complexity of the output waveguide chain otherwise needed to convert...

  6. Studies on the sintering of ceramics applying 30 GHz microwave heating; Untersuchungen zum Sinterprozess von Keramiken mit 30 GHz Millimeterwellen

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, S.; Link, G.; Feher, L. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Physik; Thumm, M. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Physik; Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Hoechstfrequenztechnik und Elektronik

    1999-07-01

    The sintering process is one of the most critical steps in ceramics production. The paper explains research and experimental work performed at Karlsruhe Research Center since 1994, focusing on the heating technology using extra high frequency waves, or microwaves, and the results obtained in a pilot plant. Advantages as compared to conventional heating methods are shown. (orig./MM) [German] Der Sintervorgang gehoert zu den kritischsten Phasen bei der Herstellung von Keramiken. Seit vielen Jahren werden am Forschungszentrum Karlsruhe Experimente zur Verarbeitung von keramischen Werkstoffen durchgefuehrt. Ein Schwerpunkt der Arbeiten liegt seit 1994 auf der Materialprozesstechnik im Millimeterwellenfeld. Dazu wird am Institut fuer Technische Physik eine Technologie-Gyrotron Anlage genutzt. Diese Pilotanlage dient zur Untersuchung des Einflusses von Millimeterwellen auf den Sinterprozess. Untersuchungen an unterschiedlichen Struktur- und Funktionskeramiken zeigen im Vergleich zu konventionellen Technologien eindeutige Vorteile bei der Vewendung von Mikro- bzw. Millimeterwellen. (orig.)

  7. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Science.gov (United States)

    Shimozuma, T.; Kobayashi, S.; Ito, S.; Ito, Y.; Kubo, S.; Yoshimura, Y.; Nishiura, M.; Igami, H.; Takahashi, H.; Mizuno, Y.; Okada, K.; Mutoh, T.

    2015-03-01

    In a high power Electron Cyclotron Resonance Heating (ECRH) system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  8. Plasma heating and current drive using intense, pulsed microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B.I.; Cohen, R.H.; Nevins, W.M.; Rognlien, T.D.; Bonoli, P.T.; Porkolab, M.

    1988-01-01

    The use of powerful new microwave sources, e.g., free-electron lasers and relativistic gyrotrons, provide unique opportunities for novel heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. These high-power, pulsed sources have a number of technical advantages over conventional, low-intensity sources; and their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. The Microwave Tokamak Experiment at Lawrence Livermore National Laboratory will provide a test for some of these new heating and current-drive schemes. This paper reports theoretical progress both in modeling absorption and current drive for intense pulses and in analyzing some of the possible complications that may arise, e.g., parametric instabilities and nonlinear self-focusing. 22 refs., 9 figs., 1 tab.

  9. Plasma heating and current drive using intense, pulsed microwaves

    International Nuclear Information System (INIS)

    The use of powerful new microwave sources, e.g., free-electron lasers and relativistic gyrotrons, provide unique opportunities for novel heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. These high-power, pulsed sources have a number of technical advantages over conventional, low-intensity sources; and their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. The Microwave Tokamak Experiment at Lawrence Livermore National Laboratory will provide a test for some of these new heating and current-drive schemes. This paper reports theoretical progress both in modeling absorption and current drive for intense pulses and in analyzing some of the possible complications that may arise, e.g., parametric instabilities and nonlinear self-focusing. 22 refs., 9 figs., 1 tab

  10. Simulation and measurement of an electron beam in a wiggler magnetic field

    International Nuclear Information System (INIS)

    Sources of high quality beams of spinning electron beams are critical to efficient free electron devices including FELs, CARMs and gyrotrons. Bifilar helical wigglers can take a beam with little perpendicular momentum and add perpendicular momentum, spinning up the beam. The effect of the electron beam self fields on the beam quality will be important. A computer simulation has been written which can simulate the behavior of electron beams in the wiggler region including the effects of the beam self-electric fields. The equations used in the code are described. Several tests of the code are presented. Results of simulation of a bifilar helical wiggler are described. Measurement of beam parameters is also necessary. A design for a capacitive axial velocity probe is presented. The probe has been built but is still untested due to problems with a leaky flange. 15 refs

  11. DIII-D research operations annual report to the U.S. Department of Energy, October 1, 1996 through September 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    The main goals of the DIII-D experiments in 1997 were, by extending and integrating the understanding of fusion science, to make progress in the tokamak concept improvements as delineated in the DIII-D Long Range Plan and to make substantial contributions to urgently needed R and D for the ITER Engineering Design Activity. For these purposes, the authors modified the top divertor to include pumping with baffling of high triangularity shaped plasmas and brought into operation two megawatt-level-gyrotrons for electron cyclotron heating (ECH) and off-axis current drive. The elements of the DIII-D experimental program and its objectives are organized into five topical areas: Stability and Disruption Physics, Transport and Turbulence Physics, Divertor and Boundary Physics, Wave-Particle Physics, and Integrated Fusion Science and Innovative Concept Improvement. The resulting DIII-D fusion science accomplishments are described in detail in this report. This year was characterized by a number of important activities, most notably, two 110 GHz ECH gyrotrons were installed and commissioned, the upper RDP cryopump and baffle was installed, and the ohmic heating coil lead was successfully reinforced to allow return to the design coil configuration and an increase to 7.5 V-s next year. Real-time ``Isoflux`` plasma control was implemented to control the shape and position of the plasma. This system solves the MHD equilibrium equation in real time to accurately determine the location of the plasma boundary. At the same time, the authors were able to improve their safety record with three minor accidents and no lost time accidents. The staff available for operations tasks was substantially reduced owing to recent budget reductions and this impacted a number of activities.

  12. DIII-D research operations annual report to the U.S. Department of Energy, October 1, 1996 through September 30, 1997

    International Nuclear Information System (INIS)

    The main goals of the DIII-D experiments in 1997 were, by extending and integrating the understanding of fusion science, to make progress in the tokamak concept improvements as delineated in the DIII-D Long Range Plan and to make substantial contributions to urgently needed R and D for the ITER Engineering Design Activity. For these purposes, the authors modified the top divertor to include pumping with baffling of high triangularity shaped plasmas and brought into operation two megawatt-level-gyrotrons for electron cyclotron heating (ECH) and off-axis current drive. The elements of the DIII-D experimental program and its objectives are organized into five topical areas: Stability and Disruption Physics, Transport and Turbulence Physics, Divertor and Boundary Physics, Wave-Particle Physics, and Integrated Fusion Science and Innovative Concept Improvement. The resulting DIII-D fusion science accomplishments are described in detail in this report. This year was characterized by a number of important activities, most notably, two 110 GHz ECH gyrotrons were installed and commissioned, the upper RDP cryopump and baffle was installed, and the ohmic heating coil lead was successfully reinforced to allow return to the design coil configuration and an increase to 7.5 V-s next year. Real-time ''Isoflux'' plasma control was implemented to control the shape and position of the plasma. This system solves the MHD equilibrium equation in real time to accurately determine the location of the plasma boundary. At the same time, the authors were able to improve their safety record with three minor accidents and no lost time accidents. The staff available for operations tasks was substantially reduced owing to recent budget reductions and this impacted a number of activities

  13. RESEARCH PROGRESS AND HARDWARE SYSTEMS AT DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN,P.I; THE DIII-D TEAM

    2003-10-01

    OAK-B135 During the last two years significant progress has been made in the scientific understanding of DIII-D plasmas. Much of this progress has been enabled by the addition of new hardware systems. The electron cyclotron (EC) system has been upgraded from 3 MW to 6 MW, by adding three 1 MW gyrotrons with diamond windows and three steerable launchers (PPPL). The new gyrotrons have been tested to 1.0 MW for 5 s. The system has been used to control the 3/2 and 2/1 neoclassical tearing modes and to locally heat the plasma and thereby indirectly control the current density. Electron cyclotron current drive ECCD has been used to directly affect the current density. A Li-beam diagnostic has been brought on-line for measuring the edge current density using Zeeman splitting. A set of 12 coils (1-coils), consisting of six picture frame coils each above and below the midplane, with a capability of 7 kA for 10 s has been installed inside the DIII-D vessel. These coils, along with the existing six C-coils, are used to apply non-axisymmetric fields to the plasma for both exciting and controlling plasma instabilities. The DIII-D digital plasma control system is now used to not just control the shape and location of the plasma but also the electron temperature, density, the NTMs, RWMs, plasma beta and disruption mitigation. Plasma disruption experiments are extended to mitigation of real time detected disruptions on DIII-D.

  14. Sub-1100 nm lasing from post-growth intermixed InAs/GaAs quantum-dot lasers

    KAUST Repository

    Alhashim, H.H.

    2015-08-15

    Impurity free vacancy disordering induced highly intermixed InAs/GaAs quantum-dot lasers are reported with high internal quantum efficiency (>89%). The lasers are shown to retain the device characteristics after intermixing and emitting in the important wavelength of ∼1070–1190 nm. The non-coated facet Fabry-Pērot post-growth wavelength tuned lasers exhibits high-power (>1.4W) and high-gain (∼50 cm −1), suitable for applications in frequency doubled green–yellow–orange laser realisation, gas sensing, metrology etc.

  15. Prevention of Neuromusculoskeletal Frailty in Slow-Aging Ames Dwarf Mice: Longitudinal Investigation of Interaction of Longevity Genes and Caloric Restriction

    OpenAIRE

    Arum, Oge; Rasche, Zachary Andrew; Rickman, Dustin John; Bartke, Andrzej

    2013-01-01

    Ames dwarf (Prop1 df/df ) mice are remarkably long-lived and exhibit many characteristics of delayed aging and extended healthspan. Caloric restriction (CR) has similar effects on healthspan and lifespan, and causes an extension of longevity in Ames dwarf mice. Our study objective was to determine whether Ames dwarfism or CR influence neuromusculoskeletal function in middle-aged (82 ± 12 weeks old) or old (128 ± 14 w.o.) mice. At the examined ages, strength was improved by dwarfism, CR, and d...

  16. High-conductivity large-area semi-transparent electrodes for polymer photovoltaics by silk screen printing and vapour-phase deposition

    DEFF Research Database (Denmark)

    Winther-Jensen, B.; Krebs, Frederik C

    2006-01-01

    Transparent electrodes based on PEDOT were prepared using a variety of techniques suitable for large area applications from 3,4-ethylenedioxythiophene (EDT) and Fe(111)tosylate. High conductivities were obtained (similar to 20 Omega(-1)) with moderate transmission in the UVvisible range 350-600 nm....... We subsequently demonstrate the application of PEDOT electrodes to flexible polyethyleneterphthalate plastic substrates (PET) prepared by this procedure for polymer photovoltaic devices with active areas of 4.2cm(2) using a 1:4 w/w mixture of MEHPPV and PCBM. We obtain typical efficiencies of 0...

  17. Dielectric barrier discharge plasma atomizer for hydride generation atomic absorption spectrometry-Performance evaluation for selenium

    Science.gov (United States)

    Duben, Ondřej; Boušek, Jaroslav; Dědina, Jiří; Kratzer, Jan

    2015-09-01

    Atomization of selenium hydride in a quartz dielectric barrier discharge (DBD) atomizer was optimized and its performance was compared to that of the externally heated quartz multiatomizer. Argon was found as the best DBD discharge gas employing a flow rate of 75 ml min- 1 Ar while the DBD power was optimized at 14 W. The detection limits reached 0.24 ng ml- 1 Se in the DBD and 0.15 ng ml- 1 Se in the multiatomizer. The tolerance of DBD to interferences is even better than with the multiatomizer.

  18. Influence of D/A ratio on photovoltaic performance of a highly efficient polymer solar cell system

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xia [State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Maojie; Zhang, Shaoqing; Huo, Lijun; Hou, Jianhui [State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Tan, Jiahui; Hu, Wenping; Li, Yongfang [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-12-18

    A new copolymer PIDTDTQx based on indacenodithiophene and quinoxaline is synthesized and characterized. The correlation between the D/A ratio, mobility, and photovoltaic properties, as well as morphology of the D/A blend based on a PIDTDTQx:PC{sub 70}BM system is investigated. The power conversion efficiency of the polymer solar cells based on PIDTDTQx/PC{sub 70}BM (1:4, w/w) reaches 7.51%. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Harmonic generation of noble-gas atoms in the Near-IR regime using ab-initio time-dependent R-matrix theory

    CERN Document Server

    Hassouneh, O; van der Hart, H W

    2014-01-01

    We demonstrate the capability of ab-initio time-dependent R-matrix theory to obtain accurate harmonic generation spectra of noble-gas atoms at Near-IR wavelengths between 1200 and 1800 nm and peak intensities up to 1.8 X 10(14) W/cm(2) . To accommodate the excursion length of the ejected electron, we use an angular-momentum expansion up to Lmax = 279. The harmonic spectra show evidence of atomic structure through the presence of a Cooper minimum in harmonic generation for Kr, and of multielectron interaction through the giant resonance for Xe. The theoretical spectra agree well with those obtained experimentally.

  20. A novel hohlraum with ultrathin depleted-uranium-nitride coating layer for low hard x-ray emission and high radiation temperature

    OpenAIRE

    Guo, Liang; Ding, Yongkun; Xing, Peifeng; Li, Sanwei; Yi, Taimin; Kuang, Longyu; Li, Zhichao; Li, Renguo; Wu, Zheqing; Jing, Longfei; Zhang, Wenhai; Zhan, Xiayu; Yang, Dong; Jiang, Bobin; Yang, Jiamin

    2014-01-01

    An ultra-thin layer of uranium nitrides (UN) has been coated on the inner surface of the depleted uranium hohlraum (DUH), which has been proved by our experiment can prevent the oxidization of Uranium (U) effectively. Comparative experiments between the novel depleted uranium hohlraum and pure golden (Au) hohlraum are implemented on Shenguang III prototype laser facility. Under the laser intensity of 6*10^14 W/cm2, we observe that, the hard x-ray (> 1.8 keV) fraction of this uranium hohlraum ...

  1. Efficient Ho:LuLiF4 laser diode-pumped at 1.15 μm.

    Science.gov (United States)

    Wang, Sheng-Li; Huang, Chong-Yuan; Zhao, Cheng-Chun; Li, Hong-Qiang; Tang, Yu-Long; Yang, Nan; Zhang, Shuai-Yi; Hang, Yin; Xu, Jian-Qiu

    2013-07-15

    We report the first laser operation based on Ho(3+)-doped LuLiF(4) single crystal, which is directly pumped with 1.15-μm laser diode (LD). Based on the numerical model, it is found that the "two-for-one" effect induced by the cross-relaxation plays an important role for the laser efficiency. The maximum continuous wave (CW) output power of 1.4 W is produced with a beam propagation factor of M(2) ~2 at the lasing wavelength of 2.066 μm. The slope efficiency of 29% with respect to absorbed power is obtained.

  2. X-ray transitions in Br XXIV-XXVIII

    International Nuclear Information System (INIS)

    Transitions in the wavelength region 4.9-8.1 A from Br , , , , and have been identified in spectra from laser-produced plasmas. The identifications were made using ab initio calculations of wavelengths and oscillator strengths. Spatially resolved spectra were recorded for laser irradiation intensities from 3 x 10/sup 13/ to 4 x 10/sup 14/ W/cm2. The dependence of the spectral lines on the distance from the target and on the irradiation intensity was very useful in distinguishing the transitions from different ionization stages

  3. Measured and Estimated Volatilisation of Naphthalene from a Sandy Soil

    DEFF Research Database (Denmark)

    Lindhardt, Bo; Christensen, Thomas Højlund

    1994-01-01

    The non-steady-state fluxes of naphthalene from an artificially contaminated sandy soil at different water contents were measured in the laboratory, at 10°C. The soil contained 1.1% of organic carbon and the water content varied between 2.8 and 14% w/w. The diffusive flux of naphthalene from the ...... the fluxes by a factor of 1.5 to 6.4. The largest deviation between predicted and observed dynamic fluxes was found at high water contents. For the cover soil, half-life times of 1 to 2 days were estimated by the model for naphthalene degradation....

  4. Preparation and Characterization of Ethosomes for Topical delivery of Aceclofenac

    OpenAIRE

    Barupal, A. K.; Gupta, Vandana; Ramteke, Suman

    2010-01-01

    The aim of present study was to prepare and characterized ethosomes of aceclofenac which may deliver the drug to targeted site more efficiently than marketed gel preparation and also overcome the problems related with oral administration of drug. The formulations were prepared with varying the quantity of ethanol 10-50% (v/v), lecithin 1-4% (w/v), propylene glycol 5-20% (v/v) and evaluated for their vesicle size, shape and surface morphology, entrapment efficiency and in vitro drug permeation...

  5. Generation of 14  W at 589  nm by frequency doubling of high-power CW linearly polarized Raman fiber laser radiation in MgO:sPPLT crystal.

    Science.gov (United States)

    Surin, A A; Borisenko, T E; Larin, S V

    2016-06-01

    We introduce an efficient, single-mode, linearly polarized continuous wave (CW) Raman fiber laser (RFL), operating at 1178 nm, with 65 W maximum output power and a narrow linewidth of 0.1 nm. Single-pass second-harmonic generation was demonstrated using a 20 mm long MgO-doped stoichiometric periodically polled lithium tantalate (MgO:sPPLT) crystal pumped by RFL radiation. Output power of 14 W at 589 nm with 22% conversion efficiency was achieved. The possibility of further power scaling is considered, as no crystal degradation was observed at these power levels. PMID:27244435

  6. Enhanced output of soft X-ray lasers using double slab targets

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, J.C.; Nilsen, J.; Chandler, E.

    1994-06-01

    Double slab neon-like niobium soft x-ray laser experiments have been performed using the Nova laser. The two slabs have their front surfaces facing in opposite directions with either a 300 {mu}m planar separation between them. Separate laser beams irradiate each slab with an intensity on target of 1.3 {times} 10{sup 14} W/cm{sup 2}. Best coupling was observed using a 300 {mu}m separation. The angular divergence of the laser is measured for single slab and double slab configurations. Comparisons to numerical models are discussed.

  7. Adiabatic mechanism of the multiply charged ion production by a laser field through ATI states of an atom

    CERN Document Server

    Kuchiev, M Yu

    1996-01-01

    ATI can be followed by an inelastic collision of the ionized electron with the parent atomic particle resulting in an excitation of the ion. It may be a continuum state excitation producing the doubly charged ion or a discrete state which also enhances the doubly charged ion production. Absorption of a few quanta above the atomic threshold is sufficient to make this mechanism work. As a result the two-electron processes can take place even in moderate fields. The example of two-electron excitations of He atoms in a 780 nm laser field with intensity above 10^{14}W/cm^2 is discussed

  8. 10W ASE-free single-mode high-power double-cladding Er 3+-Yb 3+ amplifier

    Science.gov (United States)

    Morasse, Bertrand; Agger, Søren; Hovington, Carl; Chatigny, Stéphane; Gagnon, Éric; de Sandro, Jean-Philippe; Poulsen, Christian

    2007-02-01

    We designed a high output power double cladding erbium-ytterbium fibre amplifier that showed no amplified spontaneous emission (ASE) at 1.0 μm using a quasi singlemode fibre. The reduction of the amplified stimulated emission (ASE) at 1.0 μm was found to be the combination of fibre design and temperature effect in the core. A 10W output double cladding Er-Yb amplifier with a core/cladding fibre diameter of 10/125 μm was realized with a seed signal of 1.4 W at 1563 nm and with counter-propagating pump power of 35 W at 976 nm without any significant ASE generation at 1.0 μm. The fibre also exhibits singlemode behaviour with M2 3+ and Er 3+ ions. By incorporating into our model the core temperature increase coming from the quantum defect of the Er-Yb system, we can also predict a raise in the absorption cross-section of the ytterbium ions around 1060 nm yielding to an increase of the 1 μm ASE threshold from 14 W to 35 W pump power, which allowed us to reach a 10 W output power at 1563 nm instead of 5 W normally predicted by the theory. These results show potential power scaling of the output power or double cladding erbium ytterbium amplifier using quasi singlemode core erbium ytterbium fibre avoiding the need of large core dimension that degrades the beam quality.

  9. Strong-field ionization rates of linear polyenes simulated with time-dependent configuration interaction with an absorbing potential

    Energy Technology Data Exchange (ETDEWEB)

    Krause, Pascal; Schlegel, H. Bernhard [Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489 (United States)

    2014-11-07

    The strong field ionization rates for ethylene, trans 1,3-butadiene, and trans,trans 1,3,5-hexatriene have been calculated using time-dependent configuration interaction with single excitations and a complex absorbing potential (TDCIS-CAP). The calculations used the aug-cc-pVTZ basis set with a large set of diffuse functions (3 s, 2 p, 3 d, and 1 f) on each atom. The absorbing boundary was placed 3.5 times the van der Waals radius from each atom. The simulations employed a seven-cycle cosine squared pulse with a wavelength of 800 nm. Ionization rates were calculated for intensities ranging from 0.3 × 10{sup 14} W/cm{sup 2} to 3.5 × 10{sup 14} W/cm{sup 2}. Ionization rates along the molecular axis increased markedly with increasing conjugation length. By contrast, ionization rates perpendicular to the molecular axis were almost independent of the conjugation length.

  10. Scale-up protein separation on stainless steel wide bore toroidal columns in the type-J counter-current chromatography.

    Science.gov (United States)

    Guan, Yue Hugh; Hewitson, Peter; van den Heuvel, Remco N A M; Zhao, Yan; Siebers, Rick P G; Zhuang, Ying-Ping; Sutherland, Ian

    2015-12-11

    Manufacturing high-value added biotech biopharmaceutical products (e.g. therapeutic proteins) requires quick-to-develop, GMP-compliant, easy-to-scale and cost effective preparatory chromatography technologies. In this work, we describe the construction and testing of a set of 5-mm inner diameter stainless steel toroidal columns for use on commercially available preparatory scale synchronous J-type counter-current chromatography (CCC) machinery. We used a 20.2m long column with an aqueous two-phase system containing 14% (w/w) PEG1000 and 14% (w/w) potassium phosphate at pH 7, and tested a sample loading of 5% column volume and a mobile phase flow rate of 20ml/min. We then satisfactorily demonstrated the potential for a weekly protein separation and preparation throughput of ca. 11g based on a normal weekly routine for separating a pair of model proteins by making five stacked injections on a single portion of stationary phase with no stripping. Compared to our previous 1.6mm bore PTFE toroidal column, the present columns enlarged the nominal column processing throughput by nearly 10. For an ideal model protein injection modality, we observed a scaling up factor of at least 21. The 2 scales of protein separation and purification steps were realized on the same commercial CCC device.

  11. Strong-field ionization rates of linear polyenes simulated with time-dependent configuration interaction with an absorbing potential.

    Science.gov (United States)

    Krause, Pascal; Schlegel, H Bernhard

    2014-11-01

    The strong field ionization rates for ethylene, trans 1,3-butadiene, and trans,trans 1,3,5-hexatriene have been calculated using time-dependent configuration interaction with single excitations and a complex absorbing potential (TDCIS-CAP). The calculations used the aug-cc-pVTZ basis set with a large set of diffuse functions (3 s, 2 p, 3 d, and 1 f) on each atom. The absorbing boundary was placed 3.5 times the van der Waals radius from each atom. The simulations employed a seven-cycle cosine squared pulse with a wavelength of 800 nm. Ionization rates were calculated for intensities ranging from 0.3 × 10(14) W/cm(2) to 3.5 × 10(14) W/cm(2). Ionization rates along the molecular axis increased markedly with increasing conjugation length. By contrast, ionization rates perpendicular to the molecular axis were almost independent of the conjugation length. PMID:25381499

  12. Cellulose acetate electrospun nanofibrous membrane: fabrication, characterization, drug loading and antibacterial properties

    Indian Academy of Sciences (India)

    NAZNIN SULTANA; ANISAH ZAINAL

    2016-04-01

    Cellulose-based materials are one of the most commonly used materials for biomedical applications, which normally applied as carriers for pharmaceuticals and drug-releasing scaffolds. In this study, cellulose acetate (CA) was used to fabricate the nanofibrous membrane using the electrospinning technique. CA solutions at different concentrations were prepared by dissolving the polymer in a mixture of acetic acid/acetone solvents with the ratio of 3:1. The field emission scanning electron microscope results showed that electrospinning of 10% (w/v) CA produced nanofibres with many beads. When the CA concentration was increased to 14% (w/v), bead-free nanofibres were produced. The contact angle measurement results confirmed the hydrophilic properties of nanofibres. In order to prevent common bacterial infections, a model drug, Tetracycline · HCL was incorporated into the CA nanofibres. The drug-loaded CA nanofibres showed antibacterial activity against Gram-positive and Gram-negative bacteria.CA nanofibres had high water uptake properties. The CA nanofibrous membrane was non-toxic to human skin fibroblast cells. Thus the CA nanofibres with 14% (w/v) concentration exerted suitable properties for wound healingapplication.

  13. Precipitation of Icosahedral Quasicrystalline Phase, R-phase and Laves Phase in Ferritic Alloys

    Institute of Scientific and Technical Information of China (English)

    Keisuke Yamamoto; Yoshisato Kimura; Yoshinao Mishima

    2004-01-01

    Ferritic heat resistant steels involving precipitation of intermetallic phases have drawn a growing interest for the enhancement of creep strength, while the brittleness of the intermetallic phases may lower the toughness of the alloy.Therefore, it is necessary to optimize the dispersion characteristics of the intermetallics phase through microstructural control to minimize the trade-off between the strength and toughness. The effects of α-Fe matrix substructures on the precipitation sequence, morphology, dispersion characteristics, and the stability of the intermetallic phases are investigated in Fe-Cr-W-Co-Si system. The precipitates of the Si-free Fe-10Cr-1.4W-4.5Co (at%) alloy aged at 873K are the R-phase but those of the Si-added Fe-10Cr-1.4W-4.5Co-0.3Si (at%) alloy are the icosahedral quasicrystalline phase. The precipitates in both the Si-free and Si-added alloys aged at 973K are the Laves phase. Matrix of the alloys is controlled by heat treatments as to provide three types of matrix substructures; ferrite, ferrite/martensite mixture and martensite. The hardening behavior of the alloys depends on the matrix substructures and is independent of the kinds of precipitates. In the alloys with ferrite matrix, the peak of hardness during aging at 873K shifts to longer aging time in comparison with that in the alloys with lath martensite matrix which contain numbers of nucleation sites.

  14. PREFACE: Third IAEA Technical Meeting on ECRH Physics and Technology in ITER

    Science.gov (United States)

    Cirant, S.

    2005-01-01

    This meeting belongs to a series of topical events which the International Atomic Energy Agency (IAEA, Vienna) organizes in a regular basis on crucial aspects of nuclear fusion research, or related in particular to ITER physics or a technological application relevant to the nuclear fusion reactor. Each Technical Meeting series has a specific object; the events are called on a two-three years basis and are recommended by the IAEA advisory body for Fusion, the International Fusion Research Council (IFRC) . The object of the IAEA-TM held in Como, Italy, 2-5 May 2005, was the application in ITER of powerful Electron Cyclotron waves in the millimeter wave frequency range for plasma Heating and noninductive Current Drive. The meeting was the third on this subject. There were 42 presentations to an audience of about 60 delegates from 16 countries. The main goal of this series of IAEA-TM is to bring together specialists of the different branches involved in the project, in the effort of the best understanding of the limits and capabilities of each one of the different fields of research and development. Millimeter-wave source developers, millimeter-wave system designers and plasma physicists, theoreticians and experimentalists in all of the fields, exposed their way of addressing the problem in plenary sessions attended by all participants. Discussions on the different topics of gyrotron development, launcher options and physics application were continued in forums following the presentations. The specialist reader will find in this volume in particular the latest developments concerning the frequency, the output power and the efficiency of the gyrotrons which are now being considered the preferred type of high power millimeter wave generators for ECH/ECCD applications in the fusion reactor. The debate on the launcher of the EC waves, in the form of Gaussian beams, is presently very active, with a few options on the table to be merged in one optimized and integrated design

  15. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    Science.gov (United States)

    La Haye, R. J.

    2015-12-01

    ITER is an international project to design and build an experimental fusion reactor based on the "tokamak" concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of "H-mode" and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the "missing" current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM "seeding" instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a "wild card" may be broadening of the localized ECCD by the presence of

  16. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    Energy Technology Data Exchange (ETDEWEB)

    La Haye, R. J., E-mail: lahaye@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

    2015-12-10

    ITER is an international project to design and build an experimental fusion reactor based on the “tokamak” concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of “H-mode” and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the “missing” current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM “seeding” instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a “wild card” may be broadening of the localized

  17. Korea Superconducting tokamak advanced research project - Development of heating system

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byung Ho [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    The heating and current drive systems for KSTAR based on multiple technologies (neutral beam, ion cyclotron, lower hybrid and electron cyclotron) have been designed to provide heating and current drive capabilities as well as flexibility in the control of current density and pressure profiles needed to meet the mission and research objectives of the machine. They are designed to operate for long-pulse lengths of up to 300 s. The NBI system initially delivers 8 MW of neutral beam power to the plasma from one co-directed beam line and shall be upgraded to provide 20 MW of neutral beam power with two co-directed beam lines plus one counter-directed beam line. It will be capable of being reconfigured such that the source arrangement is changed from horizontal to vertical stacking, with 6 MW beam power to the plasmas per beam line, in order to facilitate profile control. The RF system initially delivers 6 MW of rf power to the plasma, using a single four-strap antenna mounted in a midplane port. The system will be upgraded to proved 12 MW of rf power through 2 adjacent ports. In the first phase, we completed the basic design of RF system and the system have the capabilities to be operationable for pulse length up to 300 sec and in the 25-60 MHz frequency range. Lower hybrid system initially provides 1.5 MW LH rf power to the plasma at 3.7 GHz through a horizontal port, which has a capability to be operated for pulse length up to 300 sec, and shall be upgraded to provide 4.5 MW of LH rf power to the plasma. In the first phase, we completed the basic design of LHCD system which incorporate the TPX-type launcher and independently phase-changeable transmission system for the fully phased coupler. The ECH system will deliver up to 0.5 MW of power to the plasma for up to 0.5 sec. In the first phase, we completed the basic design of ECH system which includes an 84 GHz gyrotron system, a transmission system, and a launcher. The basic design of the low loss transmission system

  18. A NEW CROWBAR SYSTEM FOR THE PROTECTION OF HIGH POWER GRIDDED TUBES AND MICROWAVE DEVICES

    Energy Technology Data Exchange (ETDEWEB)

    S.G.E. PRONKO; T.E.HARRIS

    2001-04-01

    As part of the electron cyclotron heating (ECH) facility upgrade at the DIII-D National Fusion Facility, two 8.4 MW modulator/regulator power systems were designed and constructed (Ref. 1). Each power system uses a high power tetrode to modulate and regulate the cathode voltage for two 1 MW-class 110 GHz gyrotrons (Ref. 2). A critical element in the power system is the fault energy divertor, or crowbar switch, that protects the tetrode and the gyrotrons in the event of an arc fault. Traditionally, mercury filled ignitron switches are used for this application, but it was desired to eliminate hazardous materials and improve overall switching performance. The new crowbar switch system was required to meet the following requirements: Operating voltage: -105 kVdc; Peak current (750 ms e-fold): 1.6 kA; Follow-on current: <1 kA (25 ms); Charge transfer per shot: <15 Cb; and Turn-on time: <1 {micro}s. The switch that was chosen for the new design is a low pressure deuterium filled device, called a metal-arc thyratron, manufactured by Marconi Applied Technologies (Ref. 3). In addition to the new crowbar switch assembly, improved fault signal processing circuitry was developed. This new circuitry uses fiber-optics for signal and trigger transmission and a complex programmable logic device for high speed signal and logic processing. Two generations of metal-arc thyratrons have been commissioned in the two ECH power systems constructed at DIII-D. In the first, the crowbar system performed extremely well, meeting all of the operating requirements and demonstrating its ability to protect a 36 gauge copper wire from fusing (energy let-through <10 J). However, after accumulating over 500 shots, the metal-arc thyratrons lost their ability to reliably hold-off voltage. This problem was solved by Marconi with a design modification of the thyratron electrodes. The second generation tubes were installed in the second ECH power system. The crowbar system was fully commissioned and all

  19. Annual report of Naka Fusion Research Establishment for the period from April 1, 1993 to March 31, 1994

    International Nuclear Information System (INIS)

    Research and development activities at Naka Fusion Research Establishment, JAERI, are reported for the period from April 1, 1993 to March 31, 1994. The main objectives of JT-60U experiments in FY1993 were to achieve and sustain high confinement regime with current drive. The JFT-2M experiments progressed in the systematic study of the plasma responses by applying an external helical field and also in the study of the boundary plasma with electric field or current in the scrape off layer (SOL) introduced by the divertor bias system. The study in Plasma Theory and Computation focused on the ion temperature gradient instability, the linear toroidal particle simulation, the MHD stability and the analyses of burning plasma. The progresses on DIII-D experiments were obtained in the studies of divertor radiation, cryopumping and VH-mode plasma. As for the fusion engineering research, further developments of a ceramic vacuum pump and a high-resolution quadrupole mass spectrometer (QMS) were made. A high energy H- beam of 400keV and 0.18A was produced with a current density of 13mA/cm2 for 1s. Many efforts were made in developing the long pulse gyrotron and the high efficiency collector potential depression (CPD) gyrotron in the radio-frequency (RF) technology area. The main progress in the Tritium Systems Test Assembly (under US/Japan collaboration) was to demonstrate the plasma exhaust stream under non-steady tokamak operation. Heating experiments of the development 1m long divertor module for ITER were performed at a heat flux of 15MW/m2 for 30sec. The R and D of the reactor structure were focused on the major components such as non-circular bellows, fail-safe first wall, etc.. The R and D of the blanket technology were focussed on the box structure for ITER shielding blanket and the out-of-reactor testing of ITER breeding blanket. (J.P.N.)

  20. Explicit formula for the generating series of diagonal 3D rook paths

    CERN Document Server

    Bostan, Alin; van Hoeij, Mark; Pech, Lucien

    2011-01-01

    Let $a_n$ denote the number of ways in which a chess rook can move from a corner cell to the opposite corner cell of an $n \\times n \\times n$ three-dimensional chessboard, assuming that the piece moves closer to the goal cell at each step. We describe the computer-driven \\emph{discovery and proof} of the fact that the generating series $G(x)= \\sum_{n \\geq 0} a_n x^n$ admits the following explicit expression in terms of a Gaussian hypergeometric function: [G(x) = 1 + 6 \\cdot \\int_0^x \\frac{\\,\\pFq21{1/3}{2/3}{2} {\\frac{27 w(2-3w)}{(1-4w)^3}}}{(1-4w)(1-64w)} \\, dw.

  1. Development Status and Plans of the Advanced Thermoelectric Converter (ATEC) Project

    Science.gov (United States)

    Ewell, Richard; Caillat, Thierry

    2008-01-01

    Advances in thermoelectric materials with high ZT in mid-90's, revived interest in advanced thermoelectric materials at DOE, DOD and NASA NASA. JPL, in collaboration with Universities, identified promising high temperature thermoelectric materials for potential use in next generation RTGs nder DOD and NASA funding (1995 to 2005). Based on these advances the ATEC project was initiated in January 2006 to develop an advanced converter by 2010 (10-12% couple efficiency). ATEC is a technology maturation project with an off-ramp to a proposed Advanced RTG (ARTG) providing 6-8 W/kg and 8-10% system efficiency to support potential future SMD missions as early as 2017. In addition, work is continuing on advancing the TE materials technology to support development of an RTG with 12-14 W/kg and 15 to 20% efficiency by 2020.

  2. A compact, widely tunable intracavity PPLN optical parameter oscillator driven by an Nd:YAG/Cr:YAG composite crystal laser

    Science.gov (United States)

    Yang, X.-Q.; Yang, J.-F.; Zhang, B.-T.; Liu, S.-D.

    2012-03-01

    Based on periodically poled lithium niobate (PPLN), a mini intracavity optical parameter oscillator (IOPO) driven by an diode-end-pumped composite Nd3+:YAG/Cr4+:YAG laser was demonstrated. The PPLN wafer has 20 domain reversal periods from 27.8 to 31.6 μm with a step of 0.2 μm between the neighbor periods. The output signal laser of OPO can be widely tunable in the range of 1402-1676 nm by changing the period at a certain temperature of 50°C. Under the diode pump power of 14 W, the maximum average output power of 600 mW at 1534 nm with pulse width of 2.0 ns and repetition rate of 16 kHz was obtained, corresponding to a peak power of 18.7 kW and a single pulse energy of 37.5 μJ, respectively.

  3. Comparative investigation of third- and fifth-harmonic generation in atomic and molecular gases driven by midinfrared ultrafast laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Ni Jielei; Yao Jinping; Zeng Bin; Chu Wei; Li Guihua; Zhang Haisu; Jing Chenrui [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Chin, S. L. [Department of Physics, Engineering Physics and Optics, and Center for Optics, Photonics and Laser (COPL), Laval University, Laval, Quebec, G1K 7P4 (Canada); Cheng, Y.; Xu, Z. [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

    2011-12-15

    We report on the comparative experimental investigation on third- and fifth-harmonic generation (THG and FHG) in atomic and molecular gases driven by midinfrared ultrafast laser pulses at a wavelength of {approx}1500 nm. We observe that the conversion efficiencies of both the THG and FHG processes saturate at similar peak intensities close to {approx}1.5 x 10{sup 14} W/cm{sup 2} for argon, nitrogen, and air, whose ionization potentials are close to each other. Near the saturation intensity, the ratio of yields of the FHG and THG reaches {approx}10{sup -1} for all the gases. Our results show that high-order Kerr effect seems to exist; however, contribution from the fourth-order Kerr refractive index coefficient alone is insufficient to balance the Kerr self-focusing without the assistance of plasma generation.

  4. Ophiodes intermedius Boulenger, 1894 (Sauria: Anguidae

    Directory of Open Access Journals (Sweden)

    Herrera, Raúl

    2001-01-01

    Full Text Available Rep. Argentina, Prov. de Buenos Aires, Partido San Nicolás (33° 20' S, 60° 14' W. 1.- Colector: P. Núñez, MPS 17/04/1991-1. 2.- Arroyo Ramallo (Puente F.C.G.B.M. Colector: K. Giacosa, MPS 07/02/1992-1. 3.- Barrio Belgrano, Colector: L. Delgaudio, MPS 05/06/1996-1. 4.- Barrio Saavedra, Colector: C. Aragallo, MPS 13/11/1996-1. 5.- Parque R. de Aguiar (33° 17' S, 60° 15' W, Colector: O. Ramírez, MLP.S.2124, 3/4/01. 6.- Parque R. de Aguiar (33°17' S, 60° 15' W, Colector: O. Ramirez, MLP.S.2125, 20/6/01. Partido Ramallo (33° 29' S, 60° 00' W. 1.- Puerto de Ramallo Colector: D. Voglino, MLP.S.2123, 18/8/99.

  5. Relative strength of second harmonic and 3/2 omega emissions from long-scale-length laser produced plasmas

    International Nuclear Information System (INIS)

    Experiments were conducted on the planar slab targets of carbon, aluminum, and copper, using a 1.0641 μm laser, at laser intensities varying from 2 x 10/sup 12/ to 1 x 10/sup 14/ W/cm/sup 2/. The laser had a fluorescent linewidth of 4.5 A. Spectral profiles of parametrically modulated second harmonic as well as 3/2/ω/sub 0/ emissions have been measured for the long-scale-length plasmas so generated. Relative strengths of three emissions with respect to peak signal intensity and spectral energy content as a function of laser intensity are graphically reported. Results are discussed on the basis of two plasmon and parametric decay instabilities

  6. X ray emission: a tool and a probe for laser - clusters interaction; L'emission X: un outil et une sonde pour l'interaction laser - agregats

    Energy Technology Data Exchange (ETDEWEB)

    Prigent, Ch

    2004-12-01

    In intense laser-cluster interaction, the experimental results show a strong energetic coupling between radiation and matter. We have measured absolute X-ray yields and charge state distributions under well control conditions as a function of physical parameters governing the interaction; namely laser intensity, pulse duration, wavelength or polarization state of the laser light, the size and the species of the clusters (Ar, Kr, Xe). We have highlighted, for the first time, an intensity threshold in the X-ray production very low ({approx} 2.10{sup 14} W/cm{sup 2} for a pulse duration of 300 fs) which can results from an effect of the dynamical polarisation of clusters in an intense electric field. A weak dependence with the wavelength (400 nm / 800 nm) on the absolute X-ray yields has been found. Moreover, we have observed a saturation of the X-ray emission probability below a critical cluster size. (author)

  7. Dielectric barrier discharge plasma atomizer for hydride generation atomic absorption spectrometry—Performance evaluation for selenium

    International Nuclear Information System (INIS)

    Atomization of selenium hydride in a quartz dielectric barrier discharge (DBD) atomizer was optimized and its performance was compared to that of the externally heated quartz multiatomizer. Argon was found as the best DBD discharge gas employing a flow rate of 75 ml min−1 Ar while the DBD power was optimized at 14 W. The detection limits reached 0.24 ng ml−1 Se in the DBD and 0.15 ng ml−1 Se in the multiatomizer. The tolerance of DBD to interferences is even better than with the multiatomizer. - Highlights: • SeH2 atomization in a dielectric barrier discharge (DBD) was optimized for AAS. • Atomizer performance was compared for DBD and externally heated quartz atomizer. • Detection limits were quantified and interferences were studied in both atomizers. • Atomization efficiency in the DBD was estimated

  8. Photovoltaic and photophysical properties of a novel bis-3-hexylthiophene substituted quinoxaline derivative

    Energy Technology Data Exchange (ETDEWEB)

    Guenes, Serap [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Physical Chemistry, Altenberger Strasse 69, A-4040 Linz (Austria); Yildiz Technical University, Faculty of Arts and Science, Department of Physics, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey); Baran, Derya; Guenbas, Goerkem; Oezyurt, Funda; Toppare, Levent [Middle East Technical University, Faculty of Arts and Science, Department of Chemistry, 06531 Ankara (Turkey); Fuchsbauer, Anita; Sariciftci, Niyazi Serdar [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Physical Chemistry, Altenberger Strasse 69, A-4040 Linz (Austria)

    2008-09-15

    We report on the photophysical properties and photovoltaic performance of a polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline (PHTQ) as an electron donor in bulk heterojunction solar cells blended with the acceptor 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM). Devices were composed of PHTQ and varying amounts of PCBM (1:1, 1:2, 1:3, 1:4 w-w ratio). The components were spin cast from ortho-dichlorobenzene (ODCB) and characterized by measuring current-voltage characteristics under simulated AM 1.5 conditions. Efficiencies up to 0.3% have been reached. Incident photon to current efficiency (IPCE) is reported and the nanoscale morphology was investigated with atomic force microscopy (AFM). Photoinduced absorption spectroscopy confirms the photoinduced charge transfer in such donor acceptor blends. (author)

  9. The influence of cooling rate from annealing temperature on the microstructure of Haynes 230

    International Nuclear Information System (INIS)

    The effects of cooling rate from annealing temperature, which simulated the diffusion bonding process, on the microstructure of Haynes 230 (Ni-22Cr-14W-5Co) were investigated. While the grain boundaries are slightly covered with Cr-rich M23C6 carbides for the diffusion-bonded and quenched condition, precipitates were extensively present on/near the grain boundaries for the furnace-cooled specimens. For the furnace-cooled specimens, lamellar precipitates were extensively formed near the grain boundaries below 1 000 deg. C, with intervals of a few hundred nanometers. Also, grain boundaries were severely serrated for the furnace-cooled specimens. Through electron probe micro analysis and transmission electron microscope, the lamellar precipitates were identified as (Cr,W)-rich M23C6-type lamellar carbides. Despite the differences in microstructure, tensile properties were not much affected by the cooling rate. Creep tests are underway and results will be presented. (authors)

  10. Efecto del Contenido de Humedad sobre Algunas Propiedades Mecánicas de la Semilla de Vitabosa (Mucuna deeringiana Effect of Moisture Content on Some Mechanical Properties of Vitabosa (Mucuna deeringiana Seeds

    Directory of Open Access Journals (Sweden)

    Ángel Francisco Rojas Barahona

    2012-06-01

    levels and in different planes of the seed, with uniaxial compression tests and the grinding energy consumption was evaluated in an oscillating hammer mill. The proportional deformability modulus decreased when the moisture and the unitary deformation were increased, being higher in the horizontal side and the lowest value in the longitudinal side. The rupture force varied in the three sides of the seed and it decreased significantly (P<0.05 when increased moisture in the longitudinal and transverse side, while in the horizontal side increase when increased moisture of 10 to 14% w.b. The deformation increased significantly (P<0.05 with moisture from the moisture ranges from 10 to 14% w.b. The absorbed energy was increased when the moisture content varied from 10 to 14% w.b., for moisture content greater that 14% w.b., it decreased in all three planes tested. In the milling process, the specific energy consumption was proportional to the moisture content of the seed.

  11. Analysis of spreadable cheese by Raman spectroscopy and chemometric tools.

    Science.gov (United States)

    Oliveira, Kamila de Sá; Callegaro, Layce de Souza; Stephani, Rodrigo; Almeida, Mariana Ramos; de Oliveira, Luiz Fernando Cappa

    2016-03-01

    In this work, FT-Raman spectroscopy was explored to evaluate spreadable cheese samples. A partial least squares discriminant analysis was employed to identify the spreadable cheese samples containing starch. To build the models, two types of samples were used: commercial samples and samples manufactured in local industries. The method of supervised classification PLS-DA was employed to classify the samples as adulterated or without starch. Multivariate regression was performed using the partial least squares method to quantify the starch in the spreadable cheese. The limit of detection obtained for the model was 0.34% (w/w) and the limit of quantification was 1.14% (w/w). The reliability of the models was evaluated by determining the confidence interval, which was calculated using the bootstrap re-sampling technique. The results show that the classification models can be used to complement classical analysis and as screening methods.

  12. Emission of $\\gamma$ Rays by X-ray Electron-Nuclear Double Transitions

    CERN Document Server

    Olariu, S; Zoran, V; Olariu, Silviu; Olariu, Agata; Zoran, Valeriu

    1997-01-01

    This paper is about induced gamma emission. The X-ray electron-nuclear double transitions (XENDT) are processes in which a transition effected by an inner atomic electron takes place simultaneously with a nuclear electromagnetic transition. We give expressions for the cross sections of electric and magnetic XENDTs of various multipole orders. We calculate the rate of deexcitation of isomeric nuclei induced by XENDTs for the case when the holes in the atomic shells are produced by incident ionizing electrons and find that the induced nuclear deexcitation rate becomes comparable to the natural decay rate for ionizing fluxes of the order of $10^{14}$ W cm$^{-2}$. We show that for E1 and M1 nuclear processes for which there is a matching between the electron and the nuclear transition energies, the XENDTs can be used to produce pulses of

  13. Synthesis by plasma and characterization of semiconductor compounds derived of polyacetylene; Sintesis por plasma y caracterizacion de compuestos semiconductores derivados del poliacetileno

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, M.; Cruz, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Timoshina, T. [ESIQIE-IPN, 07738 Mexico D.F. (Mexico); Olayo, R. [UAM-I, 09340 Mexico D.F. (Mexico)

    2003-07-01

    In this work it is made a study of the structure and electric properties of chlorate polyethylene (PE-CI) with double and simple bonds obtained by continuous plasma with resistive coupling to 13.5 MHz. The synthesis conditions are power between 10 and 14 W and pressure of (6-7) x 10{sup -2} Torr. The synthesized PE-Cl in that way is soluble in acetone what indicates that probably is formed of short chains and not it shows the generalized inter crossing that is presented in some syntheses by plasma and that it can degrade the electric properties of these polymers. The IR and XPS analysis show the vibration of the C-C, C=C and C-CI bonds. The morphology of the polymer after being dissolved shows a compact and flat configuration. The electric conductivity has an approximately lineal behavior in an interval of 35 to 90% of relative humidity. (Author)

  14. Electron momentum distributions and photoelectron spectra of atoms driven by intense spatially inhomogeneous field

    CERN Document Server

    Ciappina, M F; Shaaran, T; Roso, L; Lewenstein, M

    2013-01-01

    We use three dimensional time-dependent Schr\\"odinger equation (3D--TDSE) to calculate angular electron momentum distributions and photoelectron spectra of atoms driven by spatially inhomogeneous fields. An example for such inhomogeneous fields is the locally enhanced field induced by resonant plasmons, appearing at surfaces of metallic nanoparticles, nanotips and gold bow-tie shape nanostructures. Our studies show that the inhomogeneity of the laser electric field plays an important role in the above threshold ionization process in the tunneling regime, causing significant modifications to the electron momentum distributions and photoelectron spectra, while its effects in the multiphoton regime appear to be negligible. Indeed, through tunneling ATI process, one can obtain higher energy electrons as well as high degree of asymmetry in the momentum space map. In this study we consider near infrared laser fields with intensities in the mid-$10^{14}$ W/cm$^{2}$ range and we use linear approximation to describe t...

  15. Measurement of ep-->e' ppi+ pi- and baryon resonance analysis.

    Science.gov (United States)

    Ripani, M; Burkert, V D; Mokeev, V; Battaglieri, M; De Vita, R; Golovach, E; Taiuti, M; Adams, G; Anciant, E; Anghinolfi, M; Asavapibhop, B; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Beard, K; Bektasoglu, M; Bellis, M; Berman, B L; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bouchigny, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Calarco, J R; Carman, D S; Carnahan, B; Cazes, A; Cetina, C; Ciciani, L; Cole, P L; Coleman, A; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Dharmawardane, K V; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Fatemi, R; Fedotov, G; Feldman, G; Feuerbach, R J; Ficenec, J; Forest, T A; Funsten, H; Gaff, S J; Gai, M; Garçon, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Girard, P; Griffioen, K; Guidal, M; Guillo, M; Guo, L; Gyurjyan, V; Hadjidakis, C; Hardie, J; Heddle, D; Heimberg, P; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hu, J; Hyde-Wright, C E; Ishkhanov, B; Ito, M M; Jenkins, D; Joo, K; Kelley, J H; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Kuhn, J; Lachniet, J; Laget, J M; Lawrence, D; Li, Ji; Livingston, K; Longhi, A; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Morand, L; Morrow, S A; Mozer, M U; Muccifora, V; Mueller, J; Murphy, L Y; Mutchler, G S; Napolitano, J; Nasseripour, R; Nelson, S O; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'Rielly, G V; Opper, A K; Osipenko, M; Park, K; Pasyuk, E; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Quinn, B; Raue, B A; Riccardi, G; Ricco, G; Ritchie, B G; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Sabourov, K; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Simionatto, S; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Strakovsky, I I; Taylor, S; Tedeschi, D J; Thoma, U; Thompson, R; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weller, H; Weygand, D P; Whisnant, C S; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

    2003-07-11

    The cross section for the reaction ep-->e(')ppi(+)pi(-) was measured in the resonance region for 1.4

  16. Electron dynamics in the carbon atom induced by spin-orbit interaction

    CERN Document Server

    Rey, H F

    2014-01-01

    We use R-Matrix theory with Time dependence (RMT) to investigate multiphoton ionization of ground-state atomic carbon with initial orbital magnetic quantum number $M_L$=0 and $M_L$=1 at a laser wavelength of 390 nm and peak intensity of 10$^{14}$ W cm$^{-2}$. Significant differences in ionization yield and ejected-electron momentum distribution are observed between the two values for $M_L$. We use our theoretical results to model how the spin-orbit interaction affects electron emission along the laser polarization axis. Under the assumption that an initial C atom is prepared at zero time delay with $M_L=0$, the dynamics with respect to time delay of an ionizing probe pulse modelled using RMT theory is found to be in good agreement with available experimental data.

  17. Instantaneous ionization rate of H$_2^+$ in intense laser field; Interpretation of the Enhanced Ionization

    CERN Document Server

    Vafaee, M; Vafaee, Z; Katanforoush, A; Vafaee, Mohsen; Sabzyan, Hassan; Vafaee, Zahra; Katanforoush, Ali

    2005-01-01

    The fixed-nuclei full dimensional time-dependent Schr \\"odinger equation is directly solved for H$_2^+$ in the linearly polarized laser field of $I \\sim 1.0 \\times 10^{14}$W cm$^{-2}$ and $\\lambda \\sim 1064 $nm. Instantaneous ionization rate has been introduced and calculated by evaluating the instantaneous imaginary energy of the system. It is shown that positive (negative) values of instantaneous imaginary energy of the system represent the incoming (outgoing) instantaneous current of electron. This approach allows us to determine not only the instantaneous intensity but also the instantaneous direction of the electronic current. The instantaneous behavior of the electron wavepacket in intense laser field can thus be probed precisely. Details of the enhanced ionization rates are studied based on the instantaneous ionization rates. This approach gives direct evidence for existence of the effect of charge-resonance-enhanced multiphoton resonances of the quasienergy states (QES) with excited electronic states ...

  18. Compression of chirp pulses from a femtosecond fiber based amplifier

    Science.gov (United States)

    Ito, Rumi; Takiuchi, Ken-ichi; Tei, Kazuyoku; Yamaguchi, Shigeru; Enokidani, Jyun; Sumida, Shin

    2015-03-01

    We demonstrate a single mode fiber based master oscillator power amplifier (MOPA) with a single polarization and a fully monolithic design. We have built a passive mode-locked polarization maintaining Yb doped fiber as the master oscillator contains a semiconductor saturable absorber mirror and a chirped fiber Bragg grating for the dispersion management. The net intracavity dispersion was managed to be slightly anomalous. The oscillator generates the 150 fs (sech2) pulses at the center wavelength of 1065 nm, and the repetition rate of 42 MHz. The oscillator output was amplified to 1.4 W from 80 mW in the single stage fiber amplifier which results in pulse shape distortion. The pulse shaping with a band pass filter and a compressor was applied to the amplified pulses. The shaping pulses have the pulse width of 90 fs and the pulse energy of 16 nJ.

  19. Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser mode-locked by reduced graphene oxide interacting with a weak evanescent field

    CERN Document Server

    Gao, Lei; Li, Yujia

    2015-01-01

    We propose a Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser passively mode-locked by reduced graphene oxide (rGO) interacting with a weak evanescent field of photonic crystal fiber (PCF). The rGO solution is filled into the cladding holes of the PCF based on total reflection, and after evaporation, the rGO flakes bear only 1/107 of the total energy in laser system, which enhances the thermal damage threshold and decreases the accumulated nonlinearity. By incorporating the saturable absorber into an Er/Yb-codoped fiber ring cavity, stable conventional soliton with a duration of 573 fs is generated, and a average output power up to 1.14 W is obtained.

  20. Outstanding efficiency in energy conversion for electric motors constructed by nanocrystalline soft magnetic alloy "NANOMET®" cores

    Science.gov (United States)

    Nishiyama, N.; Tanimoto, K.; Makino, A.

    2016-05-01

    Recently updated nanocrystalline soft magnetic Fe-Co-Si-B-P-Cu alloys "NANOMET®" exhibit high saturation magnetic flux density (Bs > 1.8 T), low coercivity (Hc motors or transformers for electrical appliances are now under developing by industry-academia collaboration. In particular, it is found that a brushless DC motor using NANOMET® core exhibited remarkable improvement in energy consumption. The prototype motor with an outer core diameter of 70 mm and a core thickness of 50 mm was constructed using laminated nano-crystallized NANOMET® ribbons. Core-loss for the constructed motor was improved from 1.4 W to 0.4 W only by replacing the non-oriented Si-steel core with NANOMET® one. The overall motor efficiency is evaluated to be 3% improvement. In this work, the relation between processing and resulting magnetic properties will be presented. In addition, feasibility for commercialization will also be discussed.

  1. Influence of atomic modeling on integrated simulations of laser-produced Au plasmas.

    Science.gov (United States)

    Frank, Yechiel; Raicher, Erez; Ehrlich, Yosi; Hurvitz, Gilad; Shpilman, Zeev; Fraenkel, Moshe; Zigler, Arie; Henis, Zohar

    2015-11-01

    Time-integrated x-ray emission spectra of laser-irradiated Au disks were recorded using transmission grating spectrometry, at laser intensities of 10(13) to 10(14) W/cm(2). Radiation-hydrodynamics and atomic physics calculations were used to simulate the emitted spectra. Three major plasma regions can be recognized: the heat wave, the corona, and an intermediate region connecting them. An analysis of the spectral contribution of these three plasma regions to the integrated recorded spectrum is presented. The importance of accurate atomic modeling of the intermediate plasma region, between the corona and the heat wave, is highlighted. The influence of several aspects of the atomic modeling is demonstrated, in particular multiply-excited atomic configurations and departure from local thermal equilibrium. PMID:26651806

  2. Nanostructured intense-laser cleaner

    CERN Document Server

    Li, Xiao Feng; Kong, Qing; Wang, Ping Xiao; Yu, Qin; Gu, Yan Jan; Qu, Jun Fan

    2016-01-01

    A nanostructured target is proposed to enhance an intense-laser contrast: when a laser prepulse is injected on a nanostructured solid target surface, the prepulse is absorbed effectively by the nanostructured surface. The nanostructure size should be less than the laser wavelength. After the prepulse absorption, the front part of the main pulse destroys the microstructure and makes the surface a flat plasma mirror. The body of the main pulse is reflected almost perfectly. Compared with the plasma mirrors, the nanostructured surface is effective for the absorption of the intense laser prepulse, higher than 10^14 W/cm2. By the nanostructured laser cleaner, the laser pulse contrast increases about a hundredfold. The nanostructured laser cleaner works well for near-future intense lasers.

  3. Dielectric barrier discharge plasma atomizer for hydride generation atomic absorption spectrometry—Performance evaluation for selenium

    Energy Technology Data Exchange (ETDEWEB)

    Duben, Ondřej [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic); Faculty of Science, Department of Analytical Chemistry, Charles University in Prague, Hlavova 8, Prague, CZ 128 43 Czech Republic (Czech Republic); Boušek, Jaroslav [Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 1058/10, 61600 Brno (Czech Republic); Dědina, Jiří [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic)

    2015-09-01

    Atomization of selenium hydride in a quartz dielectric barrier discharge (DBD) atomizer was optimized and its performance was compared to that of the externally heated quartz multiatomizer. Argon was found as the best DBD discharge gas employing a flow rate of 75 ml min{sup −1} Ar while the DBD power was optimized at 14 W. The detection limits reached 0.24 ng ml{sup −1} Se in the DBD and 0.15 ng ml{sup −1} Se in the multiatomizer. The tolerance of DBD to interferences is even better than with the multiatomizer. - Highlights: • SeH{sub 2} atomization in a dielectric barrier discharge (DBD) was optimized for AAS. • Atomizer performance was compared for DBD and externally heated quartz atomizer. • Detection limits were quantified and interferences were studied in both atomizers. • Atomization efficiency in the DBD was estimated.

  4. Quality Control of Wild Berries Honey Syrup

    Directory of Open Access Journals (Sweden)

    Laura Stan

    2013-11-01

    Full Text Available This paper presents the quality control parameters of wild berries honey syrup . The product was created in laboratory (wild berries: honey, 1:4 w/w and there were no changes recorded in overall quality over 6 months preservation at 1-2°C. Basic quality parameters of the product were evaluated: humidity, pH, acidity, hydroxymethylfurfural, diastase, total sugars and ascorbic acid. Methods developed by Internantional Honey Commission and Romanian Food Quality Standards were applied during this study. The product presented qood quality criteria and it was highly appreciated by consumers who tasted it. This study presents a valuable method to preserve fresh widberries in honey over a long period of time. The economical value of this experiment resides in making these fruits available outside the harvesting season.

  5. Shock wave propagation in soda lime glass using optical shadowgraphy

    Indian Academy of Sciences (India)

    PRASAD Y B S R; BARNWAL S; NAIK P A; YADAV Y; PATIDAR R; KAMATH M P; UPADHYAY A; BAGCHI S; KUMAR A; JOSHI A S; GUPTA P D

    2016-07-01

    Propagation of shock waves in soda lime glass, which is a transparent material, has been studied using the optical shadowgraphy technique. The time-resolved shock velocity information has been obtained (1) in single shot, using the chirped pulse shadowgraphy technique, with a temporal resolution of tens of picoseconds and (2) in multiple shots, using conventional snapshot approach, with a second harmonic probe pulse. Transient shock velocities of $(5–7) \\times 10^{6}$ cm/s have been obtained. The scaling of the shock velocity with intensity in the $2 \\times 10^{13}–10^{14}$ W/cm$^2$ range has been obtained. The shock velocity is observed to scale with laser intensity as $I^{0.38}$. The present experiments also show the presence of ionization tracks, generated probably due to X-ray hotspots from small-scale filamentation instabilities. The results and various issues involved in these experiments are discussed

  6. Double photo-electron momentum spectra of Helium at infrared wavelength

    CERN Document Server

    Zielinski, Alejandro; Scrinzi, Armin

    2015-01-01

    Double photo-electron momentum spectra of the Helium atom are calculated \\textit{ab initio} at extreme ultra-violet and near infrared wavelengths. At short wavelengths two-photon double ionization yields, two-electron energy spectra, and triply differential cross sections agree with results from recent literature. At the near infrared wavelength of $780\\,nm$ the experimental single-to-double ionization ratio is reproduced up to intensities of $4\\times 10^{14}W/cm^2$, and two-electron energy spectra and joint angular distributions are presented. The time-dependent surface flux (tSurff) approach is extended to full 3+3 spatial dimensions and systematic error control is demonstrated. We analyze our differential spectra in terms of an experimentally accessible quantitative measure of correlation.

  7. 大鼠诱发型肝癌发生发展过程中Sonic Hedgehog、Ptc和Gli1表达的改变%Alteration of Sonic Hedgehog, Ptc and Gli1 expressions in induced hepatocarcinogenesis in rats

    Institute of Scientific and Technical Information of China (English)

    贾姗姗; 李笑岩; 滕菲; 董雅莉; 张爱华; 王东

    2013-01-01

    目的 观察大鼠诱发肝癌过程中Sonic Hedgehog(Shh)信号通路相关基因的表达变化,探讨其在肝癌发生发展过程中的作用.方法 雄性Wistar大鼠48只,随机分成4组,利用二乙基亚硝胺(DEN)制备诱发性大鼠肝癌模型,应用原位核酸杂交技术检测Shh、Ptc、Gli1 mRNA在对照组、模型组(6w)、模型组(14w)、模型组(22w)大鼠肝脏癌变过程中的表达变化.结果 在模型组(6w)大鼠肝脏的肝小叶周边可见嗜酸性、气球样变性等肝细胞损伤的表现,模型组(14w)大鼠肝脏中可见肝假小叶和非典型增生结节,模型组(22w)大鼠肝脏中可见到高分化的肝细胞癌结节.Shh、Ptc、Gli1 mRNA阳性表达细胞主要分布在大鼠肝脏中的肝细胞损伤区、增生结节、癌结节、小叶间胆管上皮和癌旁组织中,Shh、Ptc、Gli1 mRNA在模型组的大鼠肝组织中表达的平均光密度值均高于对照组.结论 Shh信号通路在诱癌过程中异常激活,可能促进肝损伤后的正常修复、异常增殖及肝细胞癌变过程.%Objective To study the expression of genes related to Sonic Hedgehog(Shh) of rat liver cancer model, and to approach their function and significance in the process of liver cancer development. Methods 48 male Wistar rats were divided into 4 groups at random, and the DEN-induced hepatocarcinogenesis model was established. Based on this model, the expressions of Shh, Ptc, Gli1 mRNA were detected with in situ hybridization in the rat liver of the control and model groups (6w, 14w and 22w). Results In the model group (6w), hepatocellular injury including eosinophilic, balloon-like degeneration was observed in the outer edge of hepatic lobules. In the model group (14w) , liver pseudolobules and atypical hy-perplastic nodules were observed. And cancerous nodes of well-differentiated hepatocellular carcinoma were found in the model group (22w). The positive expression cells of Shh, Ptc, Gli1 mRNA were mainly distributed

  8. Alloyed steel

    International Nuclear Information System (INIS)

    The composition and properties are listed of alloyed steel for use in the manufacture of steam generators, collectors, spacers, emergency tanks, and other components of nuclear power plants. The steel consists of 0.08 to 0.11% w.w. C, 0.6 to 1.4% w.w. Mn, 0.35 to 0.6% w.w. Mo, 0.02 to 0.07% w.w. Al, 0.17 to 0.37% w.w. Si, 1.7 to 2.7% w.w. Ni, 0.03 to 0.07% w.w. V, 0.005 to 0.012% w.w. N, and the rest is Fe. The said steel showed a sufficiently low transition temperature between brittle and tough structures, a greater depth of hardenability, and better weldability than similar steels. (B.S.)

  9. ATI as a source for multiply charged ion production in a laser field

    CERN Document Server

    Kuchiev, M Yu

    1996-01-01

    A theory for the many-electron multi-photon process is presented. It is shown that after single-electron excitation into some level in the continuum (ATI) an inelastic collision of the excited electron with the parent atomic particle can result in an excitation of the ion. It may be the continuum state excitation giving the doubly charged ion or the discrete state which also greatly enhances the doubly charged ion production. The probability of these phenomena greatly exceeds that of the direct ionization of a single-charged ion. The single-electron ATI makes possible the two-electron process even in the moderate field. The example of two-electron excitations of He atom in a 780 nm laser field with intensity above \\approx 10^{14}W/cm^2 is discussed.

  10. Global Studies of the Sulfur Cycle Including the Influence of DMS and Fossil Fuel Sulfur on Climate and Climate Change

    Science.gov (United States)

    Penner, Joyce E.

    1998-01-01

    The indirect effect of anthropogenic aerosols, wherein aerosol particles are thought to increase cloud droplet concentrations and cloud lifetime, is the most uncertain component of climate forcing over the past 100 years. Here, for the first time, we use a mechanistic treatment of droplet nucleation and a prognostic treatment of the number of cloud droplets to study the indirect aerosol effect from changes in carbonaceous and sulfate aerosols. Cloud droplet nucleation is parameterized as a function of total aerosol number concentration, updraft velocity and a shape parameter, which takes into account the mechanism, of sulfate aerosol formation, while cloud droplet number depends on the nucleation as well as on droplet sinks. Whereas previous treatments have predicted annual average indirect effects between -1 and -2 W/sq m, we obtain an indirect aerosol effect between -0.14 W/sq m and -0.42 W/sq m in the global mean.

  11. [Corrigendum] Preventive effect of caffeine and curcumin on hepato-carcinogenesis in diethylnitrosamine-induced rats.

    Science.gov (United States)

    Fujise, Yuki; Okano, Jun-Ichi; Nagahara, Takakazu; Abe, Ryo; Imamoto, Ryu; Murawaki, Yoshikazu

    2016-09-01

    Following the publication of this article, an interested reader drew to our attention an anomaly associated with the presentation of Figs. 3 and 4; essentially, there was the direct duplication of a panel between Fig. 3B, upper left‑hand panel (the G1-10W data) and Fig. 4B, also the upper left-hand panel (the G1-14W data). In the upper-left panels of Fig. 3B and 4B, we wanted to demon-strate microscopic features of the control liver at 10 weeks and 14 weeks, respectively. After having re-examined our original data, we note that we inadvertently duplicated the picture of the control liver at 14 weeks in the upper‑left panel of Fig. 3B. A corrected version of Fig. 3 is presented below, in which the G1-10W data in Fig. 3B are now correctly shown. Since G1-10W and G1-14W are control images of the liver, exhibiting a normal appearance, this error did not affect the findings in the study. We sincerely apologize for this mistake, and thank the reader of our article who drew this matter to our attention. Furthermore, we regret any inconvenience this mistake has caused. [the original article was published in the International Journal of Oncology 40: 1779-1788, 2012; DOI: 10.3892/ijo.2012.1343]. PMID:27314753

  12. 脱硫石膏基胶凝材料用于保温墙体的探糾%Exploration of desulfurization gypsum cementitious materials used for thermal insulation wall

    Institute of Scientific and Technical Information of China (English)

    孔文栋; 薛力梨; 李强; 潘佳林

    2014-01-01

    将火力发电厂产生的脱硫石膏,粉煤灰两大废弃物以及另一种废弃物粉煤灰以一定比例混合制成胶凝材料,并与废弃的泡沫玻璃边角料复合制备成保温板,研究其强度、导热系数和表观密度等性能,并分析应用前景。结果表明:制得的保温板抗压强度在1.8MPa以上,导热系数在0.12-0.14w/(m.k)之间,干表观密度最小可以达到900kg/m3.。制得保温板成本低廉、保温性好,应具有良好的应用前景。%The coal-fired power plant desulfurization gypsum, two large waste, fly ash, and another kind of waste, to a certain proportion of fly ash to make cement materials and waste foam glass compound preparation into insulation board, examines the strength, thermal conductivity and apparent density, such as performance, and study its market prospects. Experiments prove that the compressive strength of insulation board above 1.8 MPa, the coefficient of thermal conductivity between 0.12 to 0.14 W/(m.k), dry apparent density minimum can reach 900 kg/m3.Because of new thermal insulation wall materials manufacture simple, low cost, good heat preservation, should have a good application prospect.

  13. Ka波段螺旋波纹波导回旋行波管%Linear calculation of Ka-band gyro-TWT with helical waveguide

    Institute of Scientific and Technical Information of China (English)

    薛智浩; 刘濮鲲; 杜朝海

    2012-01-01

    螺旋波纹波导回旋行波管与采用圆波导的回旋行波管相比,有较大的带宽.介绍了它的线性注波互作用理论,并用该理论计算了不同的磁场与波导表面微扰幅度对Ka波段螺旋波纹波导回旋行渡管线性增益的影响.计算结果与已报道的实验结果基本符合,说明该理论可以初步确定螺旋波纹波导回旋行波管的各项参数.%Gyrotron traveling-wave tube (gyro-TWT) with helical waveguide has wider instantaneous frequency bandwidth than that with smooth waveguide. This paper introduces the linear theory of its beam-wave interaction, and calculates the influence on linear gain of Ka-band gyro-TWT caused by changing the applied magnetic field and the amplitude of the groove. The results accord with those reported, indicating that the theory can be used to preliminarily determine the parameters of gyro-TWT assembly.

  14. 第四代ECR离子源的主要概念%Concepts for a Fourth Generation ECR Ion Source

    Institute of Scientific and Technical Information of China (English)

    C.Lyneis; D.Leitner

    2007-01-01

    To go beyond the present and planned third generation ECR ion sources operating at microwave frequencies between 20 and 30GHz to a fourth generation of sources operating above 50GHz offers new opportunities and challenges.Based on the experimentally demonstrated frequency scaling,a doubling in operating frequency could provide more intense high charge state beams with higher charge states.The technical challenges include the development of magnetic structures capable of producing 8T solenoid field and 4T sextupole fields,production and coupling of high power microwave power to heat the plasma,extraction of intense multiple charge ion beams from a region of strong magnetic field and shielding of bremstrahlung from the hot electrons.In this paper,the status of high field superconducting magnets now under development for accelerator applications,gyrotrons for microwave power and other technical aspects that would be incorporated into a fourth generation ECR ion source are explored and applied to a conceptual design.

  15. Multiple Ionization Of Metal Ions By ECR Heating Of Electrons In Vacuum Arc Plasmas

    Science.gov (United States)

    Vodopyanov, A. V.; Golubev, S. V.; Mansfeld, D. A.; Nikolaev, A. G.; Oks, E. M.; Razin, S. V.; Savkin, K. P.

    2005-03-01

    A joint research and development effort has been initiated, whose ultimate goal is the enhancement the mean ion charge states in vacuum arc metal plasmas by a combination of a vacuum arc discharge and an electron cyclotron resonance (ECR) heating. Metal plasma was generated by a special vacuum arc mini-gun and injected into mirror magnetic trap. Plasma was pumped by high frequency gyrotron-generated microwave radiation (frequency 37.5 GHz, max power 100 kW, pulse duration 1.5 ms). Using of powerful microwaves makes it possible to sustain sufficient temperature of electrons needed for multiple ionizations at high plasma density (more then 1013 cm-3). Parameter of multiple ionization efficiency Neτi, where Ne is plasma density, τi, is ion lifetime, in such a case could reach rather high value ˜109 cm-3-s. In our situation τi = Ltrap/Vi, where Ltrap is trap length, Vi is plasma gun flow velocity. The results have demonstrated substantial multiple ionization of metal ions (including metals with high melting temperature). For a metal (lead, platinum) plasma, ECR heating shifted the average ion charge up to 5+. Further increase of the ion charge states will be attained by increasing the vacuum arc plasma density and optimizing the ECR heating conditions.

  16. Preliminary design of the ITER ECH Upper Launcher

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, D., E-mail: dirk.strauss@kit.edu [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Aiello, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Chavan, R. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Cirant, S. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Baar, M. de [FOM, Van Vollenhovenlaan 659, 3527 JP, Utrecht (Netherlands); Farina, D. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Gantenbein, G. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Goodman, T.P. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Henderson, M.A. [ITER Organization, 13108 Saint-Paul-lez-Durance (France); Kasparek, W. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Kleefeldt, K. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Landis, J.-D. [Centre de Recherches en Physique des Plasmas, CRPP–EPFL, CH-1015 Lausanne (Switzerland); Meier, A. [Karlsruhe Institute of Technology, Assoc. KIT-EURATOM, D-76021 Karlsruhe (Germany); Moro, A.; Platania, P. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Plaum, B. [Institut für Plasmaforschung, IPF, D-70569 Stuttgart (Germany); Poli, E. [Max-Planck-IPP, Euratom Association, D-85748 Garching (Germany); Ramponi, G. [Istituto di Fisica del Plasma CNR, Euratom Association, 20125 Milano (Italy); Ronden, D. [FOM, Van Vollenhovenlaan 659, 3527 JP, Utrecht (Netherlands); Saibene, G. [Fusion for Energy, Barcelona (Spain); and others

    2013-11-15

    Highlights: • Front steering mirror design. • Plasma facing blanket shield module/first wall panel design. • Fixed frequency torus CVD diamond window serving as first tritium barrier. • Prototypes and tests of the above key components in the Launcher Handling and Testing Facility. -- Abstract: The design of the ITER electron cyclotron launchers recently reached the preliminary design level - the last major milestone before design finalization. The ITER ECH system contains 24 installed gyrotrons providing a maximum ECH injected power of 20 MW through transmission lines towards the tokamak. There are two EC launcher types both using a front steering mirror; one equatorial launcher (EL) for plasma heating and four upper launchers (UL) for plasma mode stabilization (neoclassical tearing modes and the sawtooth instability). A wide steering angle range of the ULs allows focusing of the beam on magnetic islands which are expected on the rational magnetic flux surfaces q = 1 (sawtooth instability), q = 3/2 and q = 2 (NTMs). In this paper the preliminary design of the ITER ECH UL is presented, including the optical system and the structural components. Highlights of the design include the torus CVD-diamond windows, the frictionless, front steering mechanism and the plasma facing blanket shield module (BSM). Numerical simulations as well as prototype tests are used to verify the design.

  17. Fusion technology programme

    International Nuclear Information System (INIS)

    KfK is involved in the European Fusion Programme predominantly in the NET and Fusion Technology part. The following fields of activity are covered: Studies for NET, alternative confinement concepts, and needs and issues of integral testing. Research on structural materials. Development of superconducting magnets. Gyrotron development (part of the Physics Programme). Nuclear technology (breeding materials, blanket design, tritium technology, safety and environmental aspects of fusion, remote maintenance). Reported here are status and results of work under contracts with the CEC within the NET and Technology Programme. The aim of the major part of this R and D work is the support of NET, some areas (e.g. materials, safety and environmental impact, blanket design) have a wider scope and address problems of a demonstration reactor. In the current working period, several new proposals have been elaborated to be implemented into the 85/89 Euratom Fusion Programme. New KfK contributions relate to materials research (dual beam and fast reactor irradiations, ferritic steels), to blanket engineering (MHD-effects) and to safety studies (e.g. magnet safety). (orig./GG)

  18. Electron-confinement studies on EBT-S using soft-x-ray techniques

    International Nuclear Information System (INIS)

    Soft x-ray bremsstrahlung measurements have been performed on the ELMO Bumpy Torus (EBT-S) plasma to determine the electron temperature T/sub e/ and electron density n/sub e/ using a calibrated Si(Li) detector over a wide range of operating conditions. The purpose of this paper is to outline the necessary assumptions and essential x-ray techniques that are inherent in soft x-ray measurements in order to investigate the electron heating and confinement properties of EBT-S. In addition, by utilizing the electron density as determined by the soft x-ray measurements, the previous EBT-S confinement analyses have been extended. The steady-state plasma of EBT-S is heated by microwaves using a cw gyrotron that can operate up to power levels of 200 kW. From the soft x-ray measurements, both the electron temperature and density are found to increase at higher microwave power levels. For operation at microwave power levels of 200 kW, T/sub e/ approaches 1 keV while n/sub e/ approaches 1.2 x 1012 cm-3. In general, confinement properties are found to improve with increased microwave power. The data are compared with neoclassical transport scaling and the electron transport is found to be collisionless (nu/Ω < 1) as well as neoclassical

  19. Development of a 2 MW CW Waterload for Electron Cyclotron Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    R. Lawrence,Ives; Maxwell Mizuhara; George Collins; Jeffrey Neilson; Philipp Borchard

    2012-11-09

    Calabazas Creek Research, Inc. developed a load capable of continuously dissipating 2 MW of RF power from gyrotrons. The input uses HE11 corrugated waveguide and a rotating launcher to uniformly disperse the power over the lossy surfaces in the load. This builds on experience with a previous load designed to dissipate 1 MW of continuous RF power. The 2 MW load uses more advanced RF dispersion to double the capability in the same size device as the 1 MW load. The new load reduces reflected power from the load to significantly less than 1 %. This eliminates requirements for a preload to capture reflected power. The program updated control electronics that provides all required interlocks for operation and measurement of peak and average power. The program developed two version of the load. The initial version used primarily anodized aluminum to reduce weight and cost. The second version used copper and stainless steel to meet specifications for the ITER reactor currently under construction in France. Tests of the new load at the Japanese Atomic Energy Agency confirmed operation of the load to a power level of 1 MW, which is the highest power currently available for testing the load. Additional tests will be performed at General Atomics in spring 2013. The U.S. ITER organization will test the copper/stainless steel version of the load in December 2012 or early in 2013. Both loads are currently being marketed worldwide.

  20. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R.

    2014-10-01

    A Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The initial system takes a single point measurement and will be used to assess options for an upgrade to a multi-point system providing electron temperature and density profiles. This single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both ohmically driven, current-carrying plasmas and future gyrotron-heated stellarator plasmas. A principle design goal is to minimize stray laser light, geometrically on the machine side and spectrally on the collection side, to allow measurements of both full and half Thomson scattered spectral profiles. The beam, generated by a frequency doubled Continuum 2 J Nd:YaG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize stray light. Light collection, spectral processing, and signal detection are accomplished with an f / # ~ 1 aspheric lens, a Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. The estimated number of scattered photons per channel will be of the order of 5 ×103 with a signal to noise ratio of S / N = 19 This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  1. Theory and design of a TE01-TE11 mode converter

    International Nuclear Information System (INIS)

    In the ECRH heating experiment on TFR at Fontenay-aux-Roses, carried out by the group FOM-CEA, 600 kW of microwave power has to be radiated into the plasma. The polarization should be parallel to the main magnetic field used for confining the plasma so that the ordinary mode is excited. The microwave power, generated by three 60 GHz gyrotrons, is transported in a circular waveguide. To keep the ohmic losses low, the TE01-mode is used for the transport. Radiation from a truncated waveguide with this mode will not give the polarization needed. Just before launching, the TE01-mode is therefore converted to the TE11-mode which has a field pattern very well suited for exciting the ordinary mode. To design mode converters of this type the Maxwell equations are transformed into generalized telegraphist equations, a set of linear differential equations which is equal to the set of equations describing the currents and voltages in mutually coupled transmission lines or in mutually coupled tuned LC-circuits. Power can be transferred from one circuit to another with different resonant frequency by reversing the sign of the coupling at certain points in time. In the microwave analogon this corresponds to a change of curvature along the axis of the guide which leads to a wiggling axis. 12 refs.; 13 figs.; 75 schemes; 4 tabs

  2. Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade

    CERN Document Server

    Rasmussen, J; Stejner, M; Salewski, M; Jacobsen, A S; Korsholm, S B; Leipold, F; Meo, F; Michelsen, P K; Moseev, D; Schubert, M; Stober, J; Tardini, G; Wagner, D

    2013-01-01

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurem...

  3. Improved Collective Thomson Scattering measurements of fast ions at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Salewski, M.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K. [Association Euratom-DTU, Technical University of Denmark, Department of Physics, DTU Riso/ Campus, DK-4000 Roskilde (Denmark); Moseev, D. [Association Euratom-FOM Institute DIFFER, 3430 BE Nieuwegein (Netherlands); Schubert, M.; Stober, J.; Tardini, G.; Wagner, D.; Collaboration: ASDEX Upgrade Team

    2014-08-21

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurement volume located close to the centre of the plasma. The measurements agree quantitatively with predictions of numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments.

  4. Transmission lines and launching systems for ECRH on the garching stellarators W VIIa and W VII-AS

    International Nuclear Information System (INIS)

    The transmission lines and launching systems for non ohmic plasma production and heating by ECR-waves at 28 GHz (200 kW, 40 ms) and 70 GHz (200 kW, 100 ms) in the Garching Wendelstein Stellarator W VIIa and at 70 GHz (800 kW, cw) in the future Advanced Stellarator W VII-AS are described. The ECRH systems meet the requirements for neutral gas breakdown (R-wave), heating of a cold plasma (X-mode) and heating of a warm plasma (0-mode) in a combined way. Periodically modulated wall mode converters (sinusoidal m=0 radius modulation, a0=31.75 mm at 28 GHz, a0=13.9 mm at 70 GHz) convert the circular electric TE/sub on/ gyrotron output mode mixture (mainly TE02 mode) into a pure TE01 wave which is used for the long distance transmission in smooth overmoded waveguides (I.D. = 63.5 mm). At the converter inputs the phases between the TE/sub on/ modes are matched by phase shifters. The measured conversion efficiency for characteristic mode mixtures (TE02/TE01/TE03) at 28 GHz is about 98 %. For the geometrical and electrical matching of different waveguide diameters waveguide tapers with approximate Tschebycheff mode-conversion responses are used

  5. PROGRESS TOWARD SUSTAINED HIGH-PERFORMANCE ADVANCED TOKAMAK DISCHARGES IN DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    J.R. FERRON; D.P. BREEAN; T.A. CASPER; A.M. GAROFALO; C.M. GREENFIELD; A.W. HYATT; R.J. JAYAKUMAR; L.C. JOHNSON; J.E. KINSEY; R.J. LaHAYE; L.L. LAO; E.A. LAZARUS; J. LOHR; T.C. LUCE; M. MURAKAMI; M. OKABAYASHI; C.C. PETTY; P.A. POLITZER; R. PRATER; H. REIMERDES; E.J. STRAIT; T.S. TAYLOR; A.D. TURNBULL; J.G. WATKINS; M.R. WADE; W.P. WEST

    2002-07-01

    Key elements of a sustained advanced tokamak discharge in DIII-D are a large fraction of the total current from bootstrap current (f{sub BS}) and parameters that optimize the capability to use electron cyclotron current drive (ECCD) at {rho} {approx} 0.5 to maintain the desired current profile [1-4]. Increased f{sub BS} results from increasing both the normalized beta ({beta}{sub N}) and the minimum value of the safety factor (q{sub min}). Off-axis ECCD is, for the available gyrotron power, optimized at high {beta}{sub N}, high electron temperature (T{sub e}) and low electron density (n{sub e}). As previously reported [2-4], these required elements have been separately demonstrated: density control at high {beta}{sub N} with n{sub e} {le} 5 x 10{sup 19} m{sup -3} using divertor-region pumping, stability at high {beta}, and off-axis ECCD at the theoretically predicted efficiency. This report summarizes recent work on optimizing and integrating these results through evaluation of the dependence of the beta limit on q{sub min} and q{sub 95}, exploration of discharges with relatively high q{sub min}, testing of feedback control of T{sub e} for control of the q profile evolution, and modification of the current profile time evolution when ECCD is applied.

  6. ECRH Resonance Position Measurement in TCV

    Science.gov (United States)

    Duval, B. P.; Goodman, T.; Henderson, M.; Mandrin, P.; Moret, J.-M.; Pochelon, A.

    1997-11-01

    A precise knowledge of the magnetic field is imperative for ECRH experiments in order to situate the position of the cyclotron resonance with respect to the magnetic surfaces. 20-40kW of 1^st harmonic 40.3GHz gyrotron radiation was injected into the vessel pre-filled with neutral deuterium with only the toroidal magnetic field coils energised. A 128 channel vertical multichannel D_α camera measured the spatial distribution of the light emission with major radius together with a 9 channel horizontal D_α camera to measure the vertical extent of the emitting region. The main cyclotron and upper hybrid resonance locations were measured for nominal magnetic fields in the range of 1.1 - 1.47T and compared to the field deduced from the magnetic pickup coils. A correction to the nominal value of ~ -2% was determined which corresponds to ~1.7cm at the full field resonance position. The effect of this displacement is shown for a series of experiments in which 500kW of 2^nd harmonic 80.2GHz power was injected into a plasma κ ~1.3 across the region of the rational q = 1 surface.

  7. Possible standoff detection of ionizing radiation using high-power THz electromagnetic waves

    Science.gov (United States)

    Nusinovich, Gregory S.; Sprangle, Phillip; Romero-Talamas, Carlos A.; Rodgers, John; Pu, Ruifeng; Kashyn, Dmytro G.; Antonsen, Thomas M., Jr.; Granatstein, Victor L.

    2012-06-01

    Recently, a new method of remote detection of concealed radioactive materials was proposed. This method is based on focusing high-power short wavelength electromagnetic radiation in a small volume where the wave electric field exceeds the breakdown threshold. In the presence of free electrons caused by ionizing radiation, in this volume an avalanche discharge can then be initiated. When the wavelength is short enough, the probability of having even one free electron in this small volume in the absence of additional sources of ionization is low. Hence, a high breakdown rate will indicate that in the vicinity of this volume there are some materials causing ionization of air. To prove this concept a 0.67 THz gyrotron delivering 200-300 kW power in 10 microsecond pulses is under development. This method of standoff detection of concealed sources of ionizing radiation requires a wide range of studies, viz., evaluation of possible range, THz power and pulse duration, production of free electrons in air by gamma rays penetrating through container walls, statistical delay time in initiation of the breakdown in the case of low electron density, temporal evolution of plasma structure in the breakdown and scattering of THz radiation from small plasma objects. Most of these issues are discussed in the paper.

  8. Advanced Design of the First Quasi-optical Transmission Line for ECRH at TJ-II

    International Nuclear Information System (INIS)

    TJ-II plasma start-up and heating are made by electron cyclotron resonance waves at the second harmonic of the electron cyclotron frequency. The microwave power of the gyrotrons is transmitted by two quasi-optical transmission lines. The first line launches the microwave power under fixed injection geometry, i. e. there is no a possibility to change the launching angle the wave polarization. Due to the long distance between the last focusing mirror and the center TJ-II vessel the beam is quite wide at plasma border. The second line has a moveable mirror installed inside the TJ-II vessel. To get high absorption efficiency and a narrow energy deposition profile the internal mirror focuses the wave beam at plasma center. The beam width is about 2 cm. To get more flexibility in experiments on heating and current drive the first transmission line needs to be upgraded. The designs is presented in this report. It includes and internal mirror to focus the beam and to change the injection angle. A polarizer consisting in two corrugated mirrors will be incorporated to get any wave polarization. Two mirrors with an array of coupling holes and calorimetric measurements of the energy absorbed in the barrier window will permit the estimation of the microwave power launched the TJ-II. (Author) 13 refs

  9. ECRH/EBWH system for NSTX-U

    Directory of Open Access Journals (Sweden)

    Hosea J.C.

    2012-09-01

    Full Text Available The National Spherical Torus Experiment Upgrade (NSTX-U will operate at an axial toroidal field of up to 1 T, about twice the field available on NSTX. A 28 GHz electron cylotron resonance heating (ECRH system is currently being planned for NSTX-U. A 1 MW 28 GHz gyrotron will be employed. Intially the system will use short, 10-50 ms, 1 MW pulses for ECRH-assisted discharge start-up. Later the pulse length will be extended to 1-5 s to study electron Bernstein wave heating (EBWH during the plasma current flat top. A mirror launcher will be used to couple microwave power to the plasma via O-mode to the slow X-mode to EBW (O-X-B double mode conversion. This paper presents a pre-conceptual design for the ECRH/EBWH system proposed for NSTX-U and includes ray tracing and Fokker-Planck modeling results for 28 GHz ECRH during plasma start-up and EBW heating and current drive during the plasma current flattop of a NSTX-U advanced H-mode plasma scenario.

  10. Experimental Investigation of Ech-Driven Suprathermal Populations on the Text Tokamak.

    Science.gov (United States)

    Boedo, Jose Armando

    1990-01-01

    We present new results of the recent X-ray spectra measurements during electron cyclotron heating (ECH) in the TEXT tokamak. A single 200 kW gyrotron was used to create TE_{11} waves at 60 GHz which are injected in TEXT in the O mode at 80 degrees to the toroidal field. Suprathermal populations were inferred from the continuum X-ray spectra during the current ramp up and during the ECH pulse. Experiments were performed with normal and inverted plasma current in order to change the injection angle and hence the driven population. Density scans and Z_{eff} scans were performed. Suprathermal temperature and density profiles were measured. These new results were compared to Fokker -Planck calculations by Vladimir Krivenski^ dagger and good agreement found (20%). Measurements of ECE on the low and high field side support our results ^ddagger. ftn^ daggerV. Krivenski, Euratom/Ciemat, Private Communication, (1989). ^ddaggerM. Austin, Auburn University, Private Communication, (1989).

  11. MULTIPLE ECH LAUNCHER CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    GREEN,M.T; PONCE,D; GRUNLOH,H.J; ELLIS,R.A; GROSNICKLE,W.H; HUMPHREY,R.L

    2003-10-01

    OAK-B135 The addition of new, high power gyrotrons to the heating and current drive arsenal at DIII-D, required a system upgrade for control of fully steerable ECH Launchers. Each launcher contains two pointing mirrors with two degrees of mechanical freedom. The two flavors of motion are called facet and tilt. Therefore up to four channels of motion per launcher need to be controlled. The system utilizes absolute encoders to indicate mirror position and therefore direction of the microwave beam. The launcher movement is primarily controlled by PLC, but future iterations of design, may require this control to be accomplished by a CPU on fast bus such as Compact PCI. This will be necessary to accomplish real time position control. Safety of equipment and personnel is of primary importance when controlling a system of moving parts. Therefore multiple interlocks and fault status enunciators have been implemented. This paper addresses the design of a Multiple ECH Launcher Control System, and characterizes the flexibility needed to upgrade to a real time position control system in the future.

  12. Solid-state dynamic nuclear polarization at 263 GHz: spectrometer design and experimental results†

    Science.gov (United States)

    Rosay, Melanie; Tometich, Leo; Pawsey, Shane; Bader, Reto; Schauwecker, Robert; Blank, Monica; Borchard, Philipp M.; Cauffman, Stephen R.; Felch, Kevin L.; Weber, Ralph T.; Temkin, Richard J.; Griffin, Robert G.; Maas, Werner E.

    2015-01-01

    Dynamic Nuclear Polarization (DNP) experiments transfer polarization from electron spins to nuclear spins with microwave irradiation of the electron spins for enhanced sensitivity in nuclear magnetic resonance (NMR) spectroscopy. Design and testing of a spectrometer for magic angle spinning (MAS) DNP experiments at 263 GHz microwave frequency, 400 MHz 1H frequency is described. Microwaves are generated by a novel continuous-wave gyrotron, transmitted to the NMR probe via a transmission line, and irradiated on a 3.2 mm rotor for MAS DNP experiments. DNP signal enhancements of up to 80 have been measured at 95 K on urea and proline in water–glycerol with the biradical polarizing agent TOTAPOL. We characterize the experimental parameters affecting the DNP efficiency: the magnetic field dependence, temperature dependence and polarization build-up times, microwave power dependence, sample heating effects, and spinning frequency dependence of the DNP signal enhancement. Stable system operation, including DNP performance, is also demonstrated over a 36 h period. PMID:20449524

  13. THE PERFORMANCE OF THE 8.4 MW MODULATOR/REGULATOR POWE SYSTEMS FOR THE ELECTRON CYCLOTRON HEATING FACILITY UPGRADE AT DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    S.G.E. PRONKO; S.W. DELAWARE; T.E. HARRIS; D. HOYT; D.H. KELLMAN; R.A. LEGG; M. LONTOC; A. NEREM; J.R. VALENTINE

    2000-11-01

    The DIII-D National Fusion Facility at General Atomics is completing the upgrade of its electron cyclotron heating (ECH) capability from the previous 3 MW at 110 GHz to 6 MW of generated microwave power. An 8.4 MW modulator/regulator (M/R) power system has been designed and constructed. Surplus hardware that was acquired from the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF program) was used as part of the design foundation. The power system, with a nominal output of -80 kV and 80 A, can supply a pair of gyrotrons with up to 10 second long pulses that may or may not be modulated. The modulator/regulator was designed about the BBC CKQ200-4 tetrode, which was the key component acquired from the LLNL program. In order to meet the performance goals of the program, substantial design modifications were needed to be made on the grid driver amplifier and the closed-loop feedback regulator circuits. Also, a newly designed crowbar switch system, featuring a high speed, thyratron-like triggered gas switch, was implemented. The modulator/regulator performance to date has been demonstrated as having <0.06% peak-to-peak ripple and square wave modulation of 50% amplitude at 2 kHz. The key features of the design of the power system and its performance will be presented in this paper.

  14. Overview of the ITER EC H and CD system and its capabilities

    International Nuclear Information System (INIS)

    The Electron Cyclotron (EC) system for the ITER tokamak is designed to inject ≥20 MW RF power into the plasma for Heating and Current Drive (H and CD) applications. The EC system consists of up to 26 gyrotrons (between 1 and 2 MW each), the associated power supplies, 24 transmission lines and 5 launchers. The EC system has a diverse range of applications including central heating and current drive, current profile tailoring and control of plasma magneto-hydrodynamic (MHD) instabilities such as the sawtooth and neoclassical tearing modes (NTMs). This diverse range of applications requires the launchers to be capable of depositing the EC power across nearly the entire plasma cross section. This is achieved by two types of antennas: an equatorial port launcher (capable of injecting up to 20 MW from the plasma axis to mid-radius) and four upper port launchers providing access from inside of mid radius to near the plasma edge. The equatorial launcher design is optimized for central heating, current drive and profile tailoring, while the upper launcher should provide a very focused and peaked current density profile to control the plasma instabilities. The overall EC system has been modified during the past 3 years taking into account the issues identified in the ITER design review from 2007 and 2008 as well as integrating new technologies. This paper will review the principal objectives of the EC system, modifications made during the past 2 years and how the design is compliant with the principal objectives.

  15. Ray tracing and ECRH absorption modeling in the HSX stellarator

    Science.gov (United States)

    Weir, G. M.; Likin, K. M.; Marushchenko, N. B.; Turkin, Y.

    2015-09-01

    To increase flexibility in ECRH experiments on the helically symmetric experiment (HSX), a second gyrotron and transmission line have been installed. The second antenna includes a steerable mirror for off-axis heating, and the launched power may be modulated for use in heat pulse propagation experiments. The extraordinary wave at the second harmonic of the electron gyrofrequency or the ordinary wave at the fundamental resonance are used for plasma start-up and heating on HSX. The tracing visualized ray tracing code (Marushchenko et al 2007 Plasma Fusion Res. 2 S1129) is used to estimate single-pass absorption and to model multi-pass wave damping in the three-dimensional HSX geometry. The single-pass absorption of the ordinary wave at the fundamental resonance is calculated to be as high as 30%, while measurements of the total absorption indicate that 45% of the launched power is absorbed. A multi-pass ray tracing model correctly predicts the experimental absorption and indicates that the launched power is absorbed within the plasma core (r/a≤slant 0.2 ).

  16. Rectangular Diamond-Lined Accelerator Structure

    CERN Document Server

    Wang, Changbiao; Yakovlev, Vyacheslav P

    2005-01-01

    For high frequency accelerators with normal-conducting structures studied by the NLC/GLC collaboration and the CLIC group, rf breakdown is the main gradient limitation. In this paper, a Ka-band rectangular dielectric-lined structure is described as an attempt to increase accelerating gradient beyond the limits suitable for metallic structures. The structure is based on amorphous dielectrics that are known to exhibit high breakdown limits (~ GV/m). An example is artificial diamond that has already been successfully used on an industrial basis for large-diameter output windows of high power gyrotrons, and is produced industrially in increasing quantities. Artificial diamond has low loss tangent, moderate dielectric constant and high breakdown limit of ~2 GV/m. In the proposed structure diamond-slabs are employed to support high-gradient acceleration fields. Interposition of vacuum gaps between the dielectric slabs and the side walls is shown to reduce Ohmic losses substantially, leading to an increase in shunt ...

  17. ECRH in LDX with Many Microwave Frequencies

    Science.gov (United States)

    Woskov, P.; Kesner, J.; Michael, P.; Garnier, D.; Mauel, M.; Davis, M.

    2010-11-01

    The large magnetic field range from 0.007 to 3.2 Tesla on closed flux surfaces around the LDX floating coil makes LDX uniquely capable of using many frequencies for electron cyclotron resonance heating (ECRH) to breakdown, build up, and sustain a core plasma. There are five sources installed with a combined injected power of 27 kW: two 2.45 GHz magnetrons at 2.5 and 1.9 kW, a 6.4 GHz, 2.5 kW klystron, a 10.5 GHz, 10 kW klystron, and a 28 GHz, 10 kW gyrotron. With all sources operating, D2 plasma density has increased to new highs near 10^18 m-3. Modeling with natural profiles shows strong ECRH absorption localized to discreet toroidal rings, each encompassing the plasma profile, that are located more inward with frequency. The relative size of the launched ECRH patterns to the absorption regions requires reflective trapping for complete absorption. Experimental observations show that higher frequencies are more efficient at generating density and lower frequencies are better at generating stored energy and energetic electrons.

  18. A mode converter to generate a Gaussian-like mode for injection into the VENUS electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lyneis, C., E-mail: CMLyneis@lbl.gov; Benitez, J.; Hodgkinson, A.; Strohmeier, M.; Todd, D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Plaum, B. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Stuttgart (Germany); Thuillier, T. [Laboratoire de Physique Subatomique et de Cosmologie, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 53 rue des martyrs 38026 Grenoble cedex (France)

    2014-02-15

    A number of superconducting electron cyclotron resonance (ECR) ion sources use gyrotrons at either 24 or 28 GHz for ECR heating. In these systems, the microwave power is launched into the plasma using the TE{sub 01} circular waveguide mode. This is fundamentally different and may be less efficient than the typical rectangular, linearly polarized TE{sub 10} mode used for launching waves at lower frequencies. To improve the 28 GHz microwave coupling in VENUS, a TE{sub 01}-HE{sub 11} mode conversion system has been built to test launching HE{sub 11} microwave power into the plasma chamber. The HE{sub 11} mode is a quasi-Gaussian, linearly polarized mode, which should couple strongly to the plasma electrons. The mode conversion is done in two steps. First, a 0.66 m long “snake” converts the TE{sub 01} mode to the TE{sub 11} mode. Second, a corrugated circular waveguide excites the HE{sub 11} mode, which is launched directly into the plasma chamber. The design concept draws on the development of similar devices used in tokamaks and stellerators. The first tests of the new coupling system are described below.

  19. State-of-the-art neoclassical tearing mode control in DIII-D using real-time steerable electron cyclotron current drive launchers

    International Nuclear Information System (INIS)

    Real-time steerable electron cyclotron current drive (ECCD) has been demonstrated to reduce the power requirements and time needed to remove 3/2 and 2/1 neoclassical tearing modes (NTMs) in the DIII-D tokamak. In a world first demonstration of the techniques required in ITER, the island formation onset is detected automatically, gyrotrons are turned on and the real-time steerable ECCD launcher mirrors are moved promptly to drive current at the location of the islands. This shrinks and suppresses the modes well before saturation using real-time motional Stark effect constrained equilibria reconstruction with advanced feedback and search algorithms to target the deposition. In ITER, this method will reduce the ECCD energy requirement and so raise Q by keeping the EC system off when the NTM is not present. Further, in the experiments with accurate tracking of pre-emptive ECCD to resonant surfaces, both 3/2 and 2/1 modes are prevented from appearing with much lower ECCD peak power than required for removal of a saturated mode. (paper)

  20. Annual review of Plasma Physics Laboratory, Kyoto University, July, 1981

    International Nuclear Information System (INIS)

    The construction of the Heliotron E was completed in June, 1980. After the preliminary examination for two months and the improvement of the power supply, the Joule heating experiment was carried out from September, 1980, to January, 1981. The experiment of electron cyclotron resonance heating was also carried out in January, 1981. Then, experiment was stopped to install the neutral beam injection apparatus. The results obtained by both experiments are reported. The target may be attained by producing high density plasma with low plasma current, and heating the plasma by NBI additionally. In the ECRH experiment, plasma was produced and heated successfully without Joule heating current, by the Gyrotron with 200 kW power output. The favorable results of the confinement experiment with current-free plasma indicate the possibility of a stationary fusion reactor of Heliotron type. The Heliotron magnetic field configuration was proposed in 1959, and since then, the experiments of Heliotron A, B, C, D and DM were carried out in succession. Now, the purpose of the experiment to prove the principle is being achieved with Heliotron E. Hope is placed on the NBI experiment in preparation. (Kako, I.)