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Sample records for varian gyrotron development

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

    International Nuclear Information System (INIS)

    Harris, T.E.

    1991-10-01

    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

  2. Status of gyrotron development

    International Nuclear Information System (INIS)

    Craig, L.J.

    1987-01-01

    This discussion briefly reviews the usual scaling law for predicting higher-power gyrotron performance from existing data, proposes another way of charting improvement progress, perhaps more applicable than the scaling laws, and shows the number of actual experimental vehicles that were required to achieve various high-power CW gyrotron goals. It also briefly touches on some of the key elements and design factors considered for CW gyrotron design. Ongoing megawatt-gyrotron experiments at Varian Associates are presented and gyrotron applications in accelerators, weapons, ceramic sintering, and fusion are assessed

  3. Soviet Development of Gyrotrons

    Science.gov (United States)

    1986-05-01

    Relationship Type of Device Remarks V, - Vc, anomalous Doppler Capable of 100 percent efficiency, CRM but more cumbersome than Cheren- kov devices V...authors; and discusses inlividual Soviet reseaLc- groups, the basic organizational units responAiLle for the CRM and gyrotron research and development. The...maintained a cCnEistEnt iecord of significant achievements; it has managed to overcome the systenic yeaxness of the Soviet R&C systeg in teimg atle to

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

    International Nuclear Information System (INIS)

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

    1985-01-01

    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 TE 031 0 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

  5. Gyrotrons

    International Nuclear Information System (INIS)

    Ebrahim, N.A.

    1987-05-01

    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

  6. Development of frequency tunable gyrotrons for plasma diagnostics

    International Nuclear Information System (INIS)

    Idehara, T.; Mitsudo, S.; Sabchevski, S.; Glyavin, M.; Ogawa, I.; Sato, M.; Kawahata, K.; Brand, G.F.

    2000-01-01

    Development of two types of frequency tunable gyrotrons are described. One is frequency step-tunable gyrotrons (Gyrotron FU Series) which cover wide range from millimeter to submillimeter wavelength region. The other is a quasi-optical gyrotron operating in 90 and 180 GHz bands. Both are applicable for plasma diagnostics as power sources. (author)

  7. Recent progress in fusion gyrotron development

    International Nuclear Information System (INIS)

    Shively, J.F.; Stone, D.S.

    1981-01-01

    The gyrotron, a microwave tube capable of producing high power output at millimeter wavelengths, has recently found applications for electron cyclotron resonance heating of plasmas in controlled thermonuclear fusion reactor experiments. This paper describes work in progress to develop a gyrotron oscillator to deliver 200 kW CW at 60 GHz (/lambda/sub //. 5 mm). A pulsed oscillator is described which produced over 200 kw peak power. A CW oscillator is under construction. The latest experimental results are presented

  8. Gyrotron development at KIT: FULGOR test facility and gyrotron concepts for DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, M., E-mail: martin.schmid@kit.edu [Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Franck, J.; Kalaria, P.; Avramidis, K.A.; Gantenbein, G.; Illy, S. [Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Jelonnek, J. [Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute of High Frequency Techniques and Electronics (IHE), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Pagonakis, I. Gr.; Rzesnicki, T. [Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Thumm, M. [Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Institute of High Frequency Techniques and Electronics (IHE), Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2015-10-15

    Highlights: • Substantial extension of the KIT gyrotron test facility FULGOR has started. • FULGOR will be able to test gyrotrons with continuous RF output power up to 4 MW. • Design of 240 GHz gyrotrons for efficient electron cyclotron current drive is progressing. • Output power of 240 GHz gyrotrons with conventional cavity up to 830 kW, with coaxial cavity up to 2 MW is feasible. • Multi-frequency operation with gyrotrons is also possible (170–267 GHz). - Abstract: At the Karlsruhe Institute of Technology (KIT), theoretical and experimental foundations for the development of future gyrotrons for fusion applications are being laid down. This includes the construction of the new Fusion Long Pulse Gyrotron Laboratory (FULGOR) test facility as well as physical design studies towards DEMO-compatible gyrotrons. Initially FULGOR will comprise of a 10 MW CW power supply, a 5 MW water cooling system (upgradeable to 10 MW), a superconducting 10 T magnet, one or two 2 MW ECRH test loads and a new control and data acquisition system for all these elements. The test facility will then be equipped to test the conventional 1 MW or coaxial 2 MW gyrotrons for DEMO, currently under design, as well as possible upgraded gyrotrons for W7-X and ITER. The design of the new high voltage DC power supply (HVDCPS) is flexible enough to handle gyrotrons with 4 MW CW output power (conceivably up to 170 GHz), but also test gyrotrons with higher frequencies (>250 GHz) which, due to physical limitations in the gyrotron design, will require less power but have more stringent demands on voltage stability.

  9. New results in development of MW output power gyrotrons for fusion systems

    International Nuclear Information System (INIS)

    Litvak, A.G.; Denisov, G.G.; Ilin, V.I.; Kurbatov, V.I.; Myasnikov, V.E.; Soluyanova, E.A.; Tai, E.M.; Usachev, S.V.; Zapevalov, V.E.

    2005-01-01

    The paper presents the latest achievements of the Russian gyrotron team in development of MW power gyrotrons for fusion installations. During two last years four new gyrotrons were designed and tested: a new version of 170 GHz gyrotron for ITER; multi-frequency (105-140 GHz) gyrotron for Asdex-Up, 84GHz gyrotron for LHD and 82.7 GHz gyrotron for SST-1. All these gyrotrons are equipped with diamond CVD windows and depressed collectors

  10. Development of field simulator to test and qualify the gyrotron local control unit for ITER-India Gyrotron Test Facility

    International Nuclear Information System (INIS)

    Shah, Ronak; Mandge, Deepak; Rathod, Vipal; Parmar, Rajvi; Dilip, E. Sharan; Yadav, Amit; Sharma, Anjali; Rao, S.L.

    2017-01-01

    High power RF sources such as a Gyrotron system are operated at required output parameter by using various auxiliary power supplies, High voltage power supplies, auxiliary services and a dedicated Local Control Unit (LCU). These sub-systems must be operated in synchronous and safe way to control the gyrotron output parameters. The LCU performs remote, synchronous and safe operation of the all the gyrotron sub-systems. Broadly the LCU functions are operational control, data acquisition, protection and safety of the gyrotron system. At ITER-India gyrotron Test Facility (IIGTF) a local control unit (LCU) is being developed to operate the complete gyrotron system. This paper presents the design, development and various features of the field simulator. It also discuss LCU functionality test cases and results obtained using field simulator

  11. Development of ITER CODAC compatible gyrotron local control system and its operation

    International Nuclear Information System (INIS)

    Ohshima, Katsumi; Oda, Yasuhisa; Takahashi, Koji; Terakado, Masayuki; Ikeda, Ryosuke; Moriyama, Shinichi; Kajiwara, Ken; Sakamoto, Keishi; Hayashi, Kazuo

    2016-03-01

    In Japan Atomic Energy Agency, an ITER relevant control system for ITER gyrotron was developed according to Plant Control Design Handbook. This control system was developed based on ITER CODAC Core System and implemented state machine control of gyrotron operation system, sequential timing control of gyrotron oscillation startup, and data acquisition. The operation of ITER 170 GHz gyrotron was demonstrated with ITER relevant power supply configuration. This system is utilized for gyrotron operation test for ITER procurement. This report describes the architecture of gyrotron local control system, its basic and detailed design, and recent operation results. (author)

  12. Development of gyrotrons for plasma diagnostics (invited)

    International Nuclear Information System (INIS)

    Woskoboinikow, P.

    1986-01-01

    Recent advances in high-frequency (>100 GHz) gyrotron technology are reviewed and application to millimeter/submillimeter wave plasma diagnostics is discussed. Gyrotrons have useful capabilities of high-power (>1 kW), long pulse/cw operation, narrow linewidth (<100 kHz), and good spatial mode quality with efficient (--90%) mode converters. These capabilities could be used to significantly improve collective Thomson scattering diagnostics for the study of instabilities, plasma waves, turbulence, and thermal ion fluctuations. Imaging applications with many detector arrays of plasma density, field direction, and microinstabilities may be possible with gyrotons. In a high-field compact ignition tokamak experiment a possible millimeter wave diagnostics window could be exploited by a gyrotron to measure a number of parameters, including alpha particle density and velocity distribution

  13. Review of gyrotron development at the Centre de Recherche en Physique des Plasmas

    International Nuclear Information System (INIS)

    Tran, M.Q.

    1990-01-01

    Gyrotron development activities at the Centre de Recherche en Physique des Plasmas in Lausanne are directed along two directions, quasi optical gyrotrons and, with less emphasis, cylindrical cavity gyrotrons. This paper will review the recent work performed in these two fields. (author) 9 refs., 5 figs

  14. Subterahertz gyrotron developments for collective Thomson scattering in LHDa)

    Science.gov (United States)

    Notake, T.; Saito, T.; Tatematsu, Y.; Kubo, S.; Shimozuma, T.; Tanaka, K.; Nishiura, M.; Fujii, A.; Agusu, La; Ogawa, I.; Idehara, T.

    2008-10-01

    Collective Thomson scattering (CTS) is expected to provide the spatially resolved velocity distribution functions of not only thermal and tail ions but also alpha particles resulting from fusion reactions. CTS using gyrotrons with frequency higher than the conventional ones used for plasma heating would have advantages to alleviate refraction, cutoff effects, and background electron cyclotron emission noise. Therefore, a high-power pulse gyrotron operating at approximately 400 GHz is being developed for CTS in Large Helical Device (LHD). A single-mode oscillation with a frequency greater than 400 GHz, applying the second-harmonic resonance, was successfully demonstrated in the first stage. At the same time, concrete feasibility study based on ray tracing, scattering spectra, and electron cyclotron emission calculations has been conducted.

  15. Gyrotron development at the Instituto de Pesquisas Espaciais

    International Nuclear Information System (INIS)

    Barroso, J.J.; Castro, P.J. de; Correa, R.A.; Galvao, G.P.; Ludwig, G.O.; Montes, A.; Nono, M.C.A.

    1987-07-01

    The conceptual design of a 35GHz gyrotron operating in the TE 01 mode, intended for plasma heating experiments, is presented. The electrooptical system is sinthesized from 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 de action of an RF field with fixed spatial distribution. The experimental activities are concentrated on the construction of a system of magnetic coils, able to generate a 15 KG magnetic induction with a fluctuation of 0.1% over an extension of 13 cm; the manufacture of caerties by using electroforming techniques; and the development of techiques for the construction of electron guns. (author) [pt

  16. Gyrotron development at the Instituto de Pesquisas Espaciais

    International Nuclear Information System (INIS)

    Barroso, J.J.; Castro, P.J. de; Correa, R.A.; Galvao, G.P.

    1987-01-01

    The conceptual design of a 35GHz gyrotron operating in the TE 021 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) [pt

  17. Quasi-optical gyrotron development at the CRPP

    International Nuclear Information System (INIS)

    Tran, M.Q.

    1990-09-01

    The operation of the 100GHz quasi-optical (Q.O.) gyrotron of the Centre de Recherches en Physique des Plasmas in Lausanne is described. Power up to 90kW and efficiency up to 12% have been achieved. Other features of the Q.O. gyrotron include single longitudinal mode operation, frequency tunability. Second harmonic emission (200GHz) has been observed with a resonator designed for operation at the fundamental. The issues pertinent to the Q.O. gyrotron concept are also discussed. (author) 26 refs., 13 figs., 2 tabs

  18. Development of frequency step tunable 1 MW gyrotron at 131 to 146.5 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Samartsev, A.; Gantenbein, G.; Dammertz, G.; Illy, S.; Kern, S.; Leonhardt, W.; Schlaich, A.; Schmid, M.; Thumm, M., E-mail: andrey.samartsev@kit.edu [Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2011-07-01

    Effective control of power absorption in tokamaks and stellarators could be achieved by the frequency tuning of ECH and CD power delivered by high-power gyrotrons. In this report some results of the development of a frequency tunable gyrotron with fused-silica Brewster window are presented. Excitation of several modes at 1 MW power level in the range of frequencies from 131 to 146.5 GHz is achieved. (author)

  19. Development of collective Thomson scattering system using the gyrotrons of sub-tera Hz region

    International Nuclear Information System (INIS)

    Tatematsu, Y.; Kubo, S.; Nishiura, M.

    2010-11-01

    Collective Thomson scattering (CTS) system is being developed for fusion plasma and CTS measurement on the large helical device (LHD) plasma is discussed. Sub-terahertz frequencies are suitable to the probe beam for CTS on LHD. According to the feasibility study, frequency around 0.4 THz is best for the CTS measurement on LHD high density plasma, and power of 100 kW is required. Thus, only gyrotrons in the sub-terahertz range can meet these parameters. At the first stage of development, second harmonic gyrotrons have been developed. A sealed-off type of gyrotrons has been manufactured to improve a demountable one. Measured output power has increased to about 60 kW. In parallel with the development of gyrotrons, an actual CTS system using a 77 GHz gyrotron originally installed for heating is being developed as a benchmark of LHD CTS. A heterodyne receiver system of a fundamental mixer with a fixed frequency local oscillator was installed on the upstream of the transmission line. The probe beam is 100% power modulated at 50 Hz to separate the scattering component from background ECE. Signals that can be attributed to the CTS were obtained and the analysis method of these data is developed. (author)

  20. Development of MW gyrotrons for fusion devices by University of Tsukuba

    International Nuclear Information System (INIS)

    Minami, R.; Kariya, T.; Imai, T.; Numakura, T.; Endo, Y.; Nakabayashi, H.; Eguchi, T.; Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Mutoh, T.; Ito, S.; Idei, H.; Zushi, H.; Yamaguchi, Y.; Sakamoto, Keishi; Mitsunaka, Y.

    2012-11-01

    Over-1 MW power gyrotrons for electron cyclotron heating (ECH) have been developed in the joint program of NIFS and University of Tsukuba. The obtained maximum outputs are 1.9 MW for 0.1 s on the 77 GHz Large Helical Device (LHD) tube and 1.0 MW for 1 ms on the 28 GHz GAMMA 10 one, which are new records in these frequency ranges. In long pulse operation, 300 kW for 40 min at 77 GHz and 540 kW for 2 s at 28 GHz were achieved. A new program of 154 GHz 1 MW development has started for high density plasma heating in LHD and the first tube has been fabricated. These lower frequency tubes like 77 GHz or 28 GHz one are also important for advanced magnetic fusion devices, which use Electron Bernstein Wave (EBW) heating / current drive. As a next activity of 28 GHz gyrotron, we have already started the development of over-1.5 MW gyrotron and a new design study of 28 GHz / 35 GHz dual frequency gyrotron, which indicates the practicability of the multi-purpose gyrotron. (author)

  1. ITER ECFR Coaxial gyrotron and window development (EU-T360). Pt. 1: Coaxial gyrotron development. Final report

    International Nuclear Information System (INIS)

    Piosczyk, B.; Braz, O.; Dammertz, G.; Kuntze, G.; Michel, G.; Moebius, A.; Thumm, M.

    1999-02-01

    Based on the experience gained with the inverse magnetron injection gun (IMIG) for coaxial cavity gyrotrons, a new 4.5 MW electron gun for operation at a cathode voltage of 90 kV and a beam current of 50 A has been designed and is currently under fabrication at Thomson Tubes Electroniques (TTE). The gun is of the diode type. Different from the LaB 6 IMIG currently used, the emission of the electrons will not be directed towards the coaxial insert but towards the anode similar like in conventional MIG gyrotron electron guns. The inner conductor is supported from the gun inner conductor side and can be aligned in a reproducible way in the fully assembled tube. The insert is cooled as required for operation at long pulses up to cw. The cathode will be equipped with an impregnated tungsten matrix emitter as used in industrial tubes. A 160/170 GHz, 1.5 MW, 100 ms pulse length coaxial gyrotron employing the new electron gun and a single-stage depressed collector has been designed. The advanced quasi-optical converter for transforming the TE -31,17 cavity mode at 165 GHz into a single RF-output wave beam (only one output window) consists of a simple launcher and two mirrors. The first mirror is quasi-elliptical and the second mirror has a non-quadratic phase-correcting surface to generate an approximately homogeneous RF-field distribution with a high fundamental Gaussian content in the window plane. First test experiments with the new gyrotron have been performed employing the available LaB 6 -IMIG. (orig.)

  2. Low-voltage gyrotrons

    International Nuclear Information System (INIS)

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.

    2013-01-01

    For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5–10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%–2% in the submillimeter wavelength region).

  3. Development of over 1 MW and multi-frequency gyrotrons for fusion

    International Nuclear Information System (INIS)

    Imai, T.; Kariya, T.; Minami, R.; Numakura, T.; Kato, T.; Endo, Y.; Ichimura, M.; Eguchi, T.; Mitsunaka, Y.; Shimozuma, T.; Kubo, S.; Takahashi, H.; Yoshimura, Y.; Igami, H.; Ito, S.; Mutoh, T.; Sakamoto, Keishi; Idei, H.; Zushi, H.; Nagasaki, K.; Sano, F.; Ono, M.

    2014-10-01

    The development of wide frequency range from 14 to 300 GHz of high power mega-watt gyrotron for fusion is in progress in University of Tsukuba. The strong development activity was carried out in collaboration with JAEA, NIFS, TETD and universities. Over-1 MW dual frequency gyrotron of new frequency range (14 – 35 GHz), where the reduction of diffraction loss and cathode optimization are quite important, has been developed for EC/EBW H and CD for GAMMA 10/PDX, QUEST, Heliotron J and NSTX-U. Output power of 1.25 MW at 28 GHz and estimated oscillation power of 1.2 MW at 35.45 GHz from the same tube have been achieved with the cathode angle improvement and two frequency window. This is the first demonstration of the over 1 MW dual-frequency operations in lower frequency, which contributes to the technology of wide band multi-frequency/multi-MW tube. The output power of 600 kW for 2 s at 28 GHz is also demonstrated. It is applied to the QUEST and has resulted higher EC-driven current than ever. As for higher frequency range, in the joint program of NIFS and Tsukuba for LHD ECH gyrotrons, a new frequency of 154 GHz has been successfully developed with a TE 28,8 cavity, which delivered 1.16 MW for 1 s and the total power of 4.4 MW to LHD plasma with other three 77 GHz tubes, which extended the LHD plasma to high T e region. All these gyrotron performances are new records in each frequency range. The sub-THz gyrotron development is also just begun in collaboration with JAEA for Demo-Reactor ECH system. (author)

  4. Development of new generation software tools for simulation of electron beam formation in novel high power gyrotrons

    Science.gov (United States)

    Sabchevski, S.; Zhelyazkov, I.; Benova, E.; Atanassov, V.; Dankov, P.; Thumm, M.; Dammertz, G.; Piosczyk, B.; Illy, S.; Tran, M. Q.; Alberti, S.; Hogge, J.-Ph

    2006-07-01

    Computer aided design (CAD) based on numerical experiments performed by using adequate physical models and efficient simulation codes is an indispensable tool for development, investigation, and optimization of gyrotrons used as radiation sources for electron cyclotron resonance heating (ECRH) of fusion plasmas. In this paper, we review briefly the state-of-the-art in the field of modelling and simulation of intense, relativistic, helical electron beams formed in the electron-optical systems (EOS) of powerful gyrotrons. We discuss both the limitations of the known computer codes and the requirements for increasing their capabilities for solution of various design problems that are being envisaged in the development of the next generation gyrotrons for ECRH. Moreover, we present the concept followed by us in an attempt to unite the advantages of the modern programming techniques with self-consistent, first-principles 3D physical models in the creation of a new highly efficient and versatile software package for simulation of powerful gyrotrons.

  5. Status of the development of the EU 170 GHz/1 MW/CW gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Pagonakis, Ioannis Gr., E-mail: ioannis.pagonakis@kit.edu [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Albajar, Ferran [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Alberti, Stefano [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Avramidis, Konstantinos [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Bonicelli, Tullio [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Braunmueller, Falk [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Bruschi, Alex [Plasma Physics Institute, National Research Council of Italy, Milano (Italy); Chelis, Ioannis [School of Electrical and Computer Engineering, National Technical University of Athens (Greece); Cismondi, Fabio [The European Joint Undertaking for ITER and The Development of Fusion Energy, Barcelona (Spain); Gantenbein, Gerd [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Hermann, Virgile [Thales Electron Devices (TED), Vélizy-Villacoublay (France); Hesch, Klaus [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Hogge, Jean-Philippe [École Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), Lausanne (Switzerland); Jelonnek, John; Jin, Jianbo; Illy, Stefan [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Ioannidis, Zisis C. [Faculty of Physics, National and Kapodistrian University of Athens (Greece); Kobarg, Thorsten [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); and others

    2015-10-15

    The progress in the development of the European 170 GHz, 1 MW/CW gyrotron for electron cyclotron heating & current drive (ECH&CD) on ITER is reported. A continuous wave (CW) prototype is being manufactured by Thales Electron Devices (TED), France, while a short-pulse (SP) prototype gyrotron is in parallel under manufacture at Karlsruhe Institute of Technology (KIT), with the purpose of validating the design of the CW industrial prototype components. The fabrication of most of the sub-assemblies of the SP prototype has been completed. In a first step, an existing magnetron injection gun (MIG) available at KIT was used. Despite this non-ideal configuration, the experiments provided a validation of the design, substantiated by an excellent agreement with numerical simulations. The tube, operated without a depressed collector, is able to produce more than 1 MW of output power with efficiency in excess of 30%, as expected, and compatible with the ITER requirements.

  6. Development of Gyrotron and JT-60U EC heating system for fusion reactor

    International Nuclear Information System (INIS)

    Sakamoto, K.; Kasugai, A.; Ikeda, Yo.

    2003-01-01

    The progress of ECH technology, for ITER and JT-60U tokamak, are presented. In the development of gyrotron, 0.9MW/9.2sec, 0.5MW/30sec, 0.3MW/60sec, etc. have been demonstrated at 170GHz. At 110GHz, 1.3MW/1.2sec, 1.2MW/4.1sec, 1MW/5sec were obtained. It is found that the reduction of the stray radiation and the enhancement of cooling capability are keys for CW operation. Four 110GHz gyrotrons are under operation in the ECH system of JT-60U. The power up to approximately 3MW/2.7sec was injected into the plasma through the poloidally movable mirrors, and contributed to the electron heating up to 26keV(n e ∼0.5x10 13 cm -3 ), and the suppression of the neo-classical tearing mode. (author)

  7. Development of gyrotron and JT-60U EC heating system for fusion reactor

    International Nuclear Information System (INIS)

    Sakamoto, K.; Kasugai, A.; Ikeda, Yo.

    2003-01-01

    The progress of ECH technology, for ITER and JT-60U tokamak, are presented. In the development of gyrotron, 0.9MW/9.2sec, 0.5MW/30sec, 0.3MW/60sec, etc. have been demonstrated at 170GHz. At 110GHz, 1.3MW/1.2sec, 1.2MW/4. 1sec. 1MW/5sec were obtained. It is found that the reduction of the stray radiation and the enhancement of cooling capability are keys for CW operation. Four 110GHz gyrotrons are under operation in the ECH system of JT-60U. The power up to approximately 3MW/2.7sec was injected into the plasma through the poloidally movable mirrors, and contributed to the electron heating up to 26keV(n e ∼0.5x10 13 cm -3 ), and the suppression of the neo-classical tearing mode. (author)

  8. Design, Development & Functional Validation of Magnets system in support of 42 GHz Gyrotron in India

    Directory of Open Access Journals (Sweden)

    Pradhan S.

    2017-01-01

    Full Text Available A multi institutional initiative is underway towards the development of 42 GHz, 200 kW gyrotron system in India under the frame work of Department of Science and Technology, Government of India. Indigenous realization comprising of design, fabrication, prototypes and functional validations of an appropriate Magnet System is one of the primary technological objective of these initiatives. The 42 GHz gyrotron magnet system comprises of a warm gun magnet, a NbTi/Cu based high homogenous superconducting cavity magnet and three warm collector magnets. The superconducting cavity magnet has been housed inside a low loss cryostat. The magnet system has been designed in accordance with gyrotron physics and engineering considerations respecting highly homogenous spatial field profile as well as maintaining steep gradient as per the compression and velocity ratios between the emission and resonator regions. The designed magnet system further ensures the co-linearity of the magnetic axis with that of the beam axis with custom winding techniques apart from a smooth collection of beam with the collector magnet profiles. The designed magnets have been wound after several R & D validations. The superconducting magnet has been housed inside a low loss designed cryostat with in-built radial and axial alignment flexibilities to certain extent. The cryostat further houses liquid helium port, liquid nitrogen ports, current communication ports, ports for monitoring helium level and other instrumentations apart from over-pressure safety intensive burst disks etc. The entire magnet system comprising of warm and superconducting magnets has been installed and integrated in the Gyrotron test set-up. The magnet system has been aligned in both warm and when the superconducting cavity magnet is cold. The integrated geometric axes have been experimentally ensured as well as the field profiles have been measured with the magnets being charged. Under experimental conditions

  9. Development of over-1 MW gyrotrons for the LHD and the GAMMA 10 ECH systems

    International Nuclear Information System (INIS)

    Imai, T.; Kariya, T.; Minami, R.

    2010-11-01

    For the ECH upgrade program of LHD and GAMMA10, over-1 MW power gyrotrons have been developed in the joint program of NIFS and University of Tsukuba. The gyrotrons for LHD and GAMMA 10 have TE 18,6 cavity and a diamond window at 77 GHz, and with TE 8,3 cavity at 28 GHz, respectively. The maximum outputs obtained are 1.9 MW for 0.1 s on the 77 GHz LHD tube and ∼ 1 MW on the 28 GHz one, which are the new records in these frequency ranges. The results of 1.8 MW for 1 s, 1.6 MW for 1.8s, 1 MW for 5 s, 300 kW for 40 min and 200 kW for 75 min were achieved at 77 GHz. In the long pulse operation, it is found that the stray RF is the major cause limiting the pulse length. Design improvements of the diffraction loss, the cavity and pitch factor α (=v sub(perpendicular)/v sub(parallel)) dispersion of the MIG have made the 77 GHz tube performance better, which have enabled to demonstrate 1.9 MW output and long pulse operation for more than 1 hour with 200 kW. The three 77 GHz gyrotrons have already been installed in the LHD ECH system and more than 3 MW has been injected into LHD plasma. In the 28 GHz long pulse operation, 400 kW for 1 sec has been obtained and it is found the higher and longer pulse operation would be possible with the operation optimization and conditioning. (author)

  10. Development of a dummy load and waveguide components for 1 MW CW gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, Kimihiro, E-mail: ioki@toyama-jp.com [Toyama Company Limited, 3816-1 Kishi, Ymakita-machi, Ashigarakami-gun, Kanagawa 258-0112 (Japan); Hiranai, Shinichi; Moriyama, Shinichi [Naka Fusion Institute, JAEA, 801-1, Mukoyama, Naka-shi, Ibaraki 311-0193 (Japan); Tanaka, Suguru [Toyama Company Limited, 3816-1 Kishi, Ymakita-machi, Ashigarakami-gun, Kanagawa 258-0112 (Japan)

    2016-11-01

    Highlights: • A dummy load is a required component for the electron cyclotron heating system to test and adjust a gyrotron or a transmission line in ITER and JT60SA. • A new design concept was developed considering reliable durability and long lifetime. • Linear movement is used as a main mechanism for the reflector to mitigate the heat deposition concentration instead of rotating reflector, and the vacuum boundary for the linear movement is simply made with bellows. • The distribution of the ceramic coating thickness is carefully optimized considering the heat deposition rate. • A prototypical dummy load will be manufactured and tested, following the design phase. - Abstract: A dummy load dissipates the radiofrequency power and is required for the electron cyclotron heating system to test and adjust a gyrotron or a transmission line in ITER and JT60SA. The dummy load is comprised of a water-cooled vacuum chamber and a reflector. The vacuum chamber has intensive cooling and the inside surface has a ceramic coating layer. It is important that the dummy load has reliable durability and long lifetime. Linear movement is used as a main mechanism for the reflector to mitigate the heat deposition concentration instead of rotating reflector. The vacuum boundary for the linear movement is simply made with bellows and the bellows is accessible from the outside. The distribution of the ceramic coating thickness is carefully optimized considering the heat deposition rate. Another critical issue is to minimize the back reflection of the RF power from the dummy load. However, it is desired to design the dummy load without the pre-dummy-load. A prototypical dummy load will be manufactured and tested, following the design phase.

  11. Gyrotron: an ECH system component

    International Nuclear Information System (INIS)

    Loring, C.M.; Eason, H.O.; Kimrey, H.D.; White, T.L.; Jory, H.R.; Evans, S.J.

    1981-01-01

    The gyrotron, or electron-cyclotron maser, in the form of a gyromonotron, is being developed as a source of millimeter wave energy for fusion plasma heating. The characteristics of this high power, high efficiency electron tube are described in terms of the requirements for the beam power supply system, the mechanical support system, the cooling system, the focusing and tuning magnets, and the waveguide system. Requirements of power level and transmission efficiency dictate the use of oversize waveguide. The implications, both to the user and to the interaction mechanisms in the gyrotron, of the use of oversize waveguide are treated. The effects of variations of various operating parameters upon the gyrotron's power output and stability are also discussed. Data from gyrotron development and system operation are used where appropriate

  12. Development program for a 200 kW, CW gyrotron. Quarterly report No. 4, April-June 1980

    International Nuclear Information System (INIS)

    Tancredi, J.J.; Caplan, M.; Sandoval, J.J.; Weiss, W.

    1980-01-01

    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, which will be 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-varyinng rf load mismatch

  13. Development program for a 200 kW, cw gyrotron. Quarterly report No. 11, January-March 1982

    International Nuclear Information System (INIS)

    Tancredi, J.J.; Caplan, M.; Sandoval, J.J.; Matranga, V.A.

    1982-01-01

    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. During this report period, the beam instability problem which plagued S/N 1 testing was evaluated in more detail. Separate tests were conducted on the gun tester and the lossy drift section, as well as both of these combined, and the results were compared to gyrotron tests on S/N 1. The instability problem now appears to be associated with RF leakage from the cavity

  14. Research on megawatt gyrotrons, January 1983-December 1984

    International Nuclear Information System (INIS)

    Read, M.E.

    1984-01-01

    During the last several years, NRL has performed research on concepts for high power gyrotrons. The work funded by the Department of Energy has been in support of industrial development of high frequency (60 to 140 GHz) CW gyrotrons, with NRL research being on the origination, development, and testing of advanced concepts. The research performed under this agreement has included experimental work on quasi-optical and complex cavity gyrotrons and theoretical efforts on these concepts as well as whispering gallery gyrotrons

  15. Development of 1 MW gyrotron and progress of ECH system for the GAMMA 10 tandem mirror in Tsukuba

    International Nuclear Information System (INIS)

    Imai, T.; Kariya, T.; Minami, R.; Shidara, H.; Endo, Y.; Harigae, M.; Nakamura, M.; Sakagoshi, Y.; Murofushi, N.; Ichimura, M.; Nakashima, Y.; Yoshikawa, M.; Yamaguchi, Y.; Sakamoto, Keishi; Kubo, S.; Shimozuma, T.; Mutoh, T.; Takahashi, H.; Mitsunaka, Y.

    2008-10-01

    High power gyrotrons with TE 4,2 cavity at 28 GHz and with TE 18,6 cavity and a diamond window at 77 GHz have been developed for GAMMA 10 and LHD in the joint program of NIFS and University of Tsukuba. The maximum outputs of 570 kW at 28 GHz and 1.1 MW at 77 GHz were obtained corresponding to each design. The operations of more than 750 kW for 5 sec. and 810 kW for 3.5 sec. were achieved in the developing tubes at 77 GHz, which is the first high power-long pulse result of the 77 GHz tube. The experimental simulation of the effect of the stray RF in the 28 GHz tube indicates the stray RF is the one of the major causes limiting gyrotron performance. The output of more than 1 MW with 40% oscillation efficiency is expected from the design of the next 28 GHz gyrotron for GAMMA 10. Installation of the polarizer in the transmission line enhanced the performance of the ECH system in GAMMA 10, that is the first result which clearly showed ∼100% X mode excitation is a key to design the efficient fundamental ECH system of strong field side injection in mirror devices. (author)

  16. Experimental results and recent developments on the EU 2 MW 170 GHz coaxial cavity gyrotron for ITER

    Directory of Open Access Journals (Sweden)

    Thumm M. K.

    2012-09-01

    Full Text Available The European Gyrotron Consortium (EGYC is responsible for developing one set of 170 GHz mm-wave sources, in support of Europe’s contribution to ITER. The original plan of targeting a 2 MW coaxial gyrotron is currently under discussion, in view of essential delays and damages. This paper reports on the latest results and plans with regard to the two 2 MW gyrotron prototypes, the industrial prototype at CRPP’s CW test stand and a modular pre-prototype at KIT. The industrial prototype was delivered to CRPP end of September 2011 and reached an output power of 2 MW at an efficiency of 45 % and with good RF beam pattern, in only four days of short pulse RF test. These results validated all design changes made in reaction to the results of the experiments in 2008. On the fifth experimental day, an internal absorber broke, terminating any further experiment with this tube. In parallel, design and experimental activities at KIT went on, in particular featuring reduced stray radiation down to 4% of the RF power. Next years’ plans for the 2 MW modular pre-prototype foresee a stepwise increase of pulse length.

  17. Development of steady-state 2 MW, 170 GHz gyrotrons for ITER

    International Nuclear Information System (INIS)

    Piosczyk, B.; Arnold, A.; Thumm, M.; Dammertz, G.; Heidinger, R.; Illy, S.; Jin, J.; Koppenburg, K.; Leonhardt, W.; Neffe, G.; Rzesnicki, T.; Schmid, M.; Yang, X.; Alberti, S.; Chavan, R.; Fasel, D.; Goodman, T.; Henderson, M.; Hogge, J.P.; Tran, M.Q.; Yovchev, I.; Erckmann, V.; Laqua, H.P.; Michel, G.; Gantenbein, G.; Kasparek, W.; Mueller, G.; Schwoerer, K.; Bariou, D.; Beunas, A.; Giguet, E.; LeCloarec, G.; Legrand, F.; Lievin, C.; Dumbrajs, O.

    2005-01-01

    A prototype of a 1 MW, CW, 140 GHz conventional gyrotron for the W7-X stellarator in Greifswald/Germany has been tested successfully and the fabrication of series tubes started. In extended studies the feasibility for manufacturing a continuously operated high power coaxial cavity gyrotron has been demonstrated and all needed data for an industrial design has been obtained. Based on this results the fabrication of a first prototype of a 2 MW, CW, 170 GHz coaxial cavity gyrotron started recently in cooperation between European research institutions and European tube industry. The prototype tube is foreseen to be tested in 2006 at CRPP Lausanne where a suitable test facility is under construction. (author)

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

    International Nuclear Information System (INIS)

    Felch, K.; Feinstein, J.; Hess, C.; Huey, H.; Jongewaard, E.; Jory, H.; Neilson, J.; Pendleton, R.; Pirkle, D.; Zitelli, L.

    1989-09-01

    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 TE 15,2,1 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

  19. 60 GHz gyrotron development program. Final report, April 1979-June 1984

    International Nuclear Information System (INIS)

    Shively, J.F.; Bier, R.E.; Caplan, M.

    1986-01-01

    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

  20. Nonstationary oscillations in gyrotrons revisited

    International Nuclear Information System (INIS)

    Dumbrajs, O.; Kalis, H.

    2015-01-01

    Development of gyrotrons requires careful understanding of different regimes of gyrotron oscillations. It is known that in the planes of the generalized gyrotron variables: cyclotron resonance mismatch and dimensionless current or cyclotron resonance mismatch and dimensionless interaction length complicated alternating sequences of regions of stationary, periodic, automodulation, and chaotic oscillations exist. In the past, these regions were investigated on the supposition that the transit time of electrons through the interaction space is much shorter than the cavity decay time. This assumption is valid for short and/or high diffraction quality resonators. However, in the case of long and/or low diffraction quality resonators, which are often utilized, this assumption is no longer valid. In such a case, a different mathematical formalism has to be used for studying nonstationary oscillations. One example of such a formalism is described in the present paper

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

    Energy Technology Data Exchange (ETDEWEB)

    Pereyaslavets, M.; Sato, M.; Shimozuma, T.; Takita, Y.; Idei, H.; Kubo, S.; Ohkubo, K.; Hayashi, K.

    1996-11-01

    To test gyrotron RF components, efficient low-power generators for rotating high-order modes of high purity are necessary. Designs of generators for the TE{sub 15,3} mode at 84 GHz and for the TE{sub 31,8} 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 TE{sub 15,3} 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)

  2. Development program for a 200-kW, c-w gyrotron. Quarterly report No. 7, January-March 1981

    International Nuclear Information System (INIS)

    Tancredi, J.J.; Caplan, M.; Sandoval, J.J.; Jordan, E.; Matranga, V.A.

    1981-01-01

    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, which will be 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 rf load mismatch. An interim program goal is to demonstrate operation at 100 ms pulse widths by 31 December 1981. During this quarter, progress was made in the areas of tube, solenoid, and facility construction. Two magnetron injection gun assemblies were completed, and one was partially evaluated as a gun tester. The superconducting solenoid was assembled, but a vacuum leak prevented early delivery in March. Construction began on the gyrotron test facility by enclosing the area and providing bake-out and vacuum processing utilities

  3. Development program for a 200-kW, cw gyrotron. Quarterly report No. 9, July-September 1981

    International Nuclear Information System (INIS)

    Tancredi, J.J.; Caplan, M.; Matranga, V.A.; Sandoval, J.J.

    1981-01-01

    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, which will be 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 rf load mismatch. The superconducting solenoid which had been sent back to the manufacturer because of an open coil, was repaired and returned to Hughes. The gyrotron S/N 1 was successfully operated at a frequency of 59.7 GHz with a power level of 160 kW peak. Diagnostic x-ray measurements of the collector area revealed a reasonable beam power density of 600 W/cm 2 , under worst case conditions of no rf output, and with no auxilary means of spreading the beam. The latter portion of this report period was spent characterizing S/N 1's rf and dc performance and evaluating an anomolous oscillation emitted from the electron gun

  4. Depressed collectors for millimeter wave gyrotrons

    International Nuclear Information System (INIS)

    Singh, A.; Granatstein, V.L.

    1992-01-01

    The main issues relating to design of depressed collectors for millimeter wave gyrotrons are discussed. A flow diagram is presented and the interlinking steps are outlined. Design studies are given for two kinds of gyrotrons on which severe constraints on the maximum radii of the collectors had been imposed; namely, for a cavity type and a quasi-optical gyrotron. A collector efficiency of the order of 70 percent is shown to be feasible for either case using careful tailoring of magnetic field profiles. A code has been developed to assist in doing this. A general approach toward initial placement of collectors has been indicated

  5. High power, 140 GHz gyrotron

    International Nuclear Information System (INIS)

    Kreischer, K.E.; Temkin, R.J.; Mulligan, W.J.; MacCabe, S.; Chaplya, R.

    1982-01-01

    The design and construction of a pulsed 100 kW, 140 GHz gyrotron is described. Initial gyrotron operation is expected in early 1982. Advances in gyrotron theory have also been carried out in support of this experimental research. The application of gyrotrons to plasma diagnostics is also under investigation. (author)

  6. First 200 kW CW operation of a 60 GHz gyrotron

    International Nuclear Information System (INIS)

    Jory, H.; Bier, R.; Evans, S.; Felch, K.; Fox, L.; Huey, H.; Shively, J.; Spang, S.

    1983-01-01

    The gyrotron is a microwave tube which employs the electron cyclotron maser interaction to produce high power output at millimeter wavelengths. It has important and growing applications for heating of plasmas in controlled thermonuclear fusion experiments. The Varian 60 GHz gyrotron has recently generated microwave power in excess of 200 kW during CW operation, wth excellent dynamic range and operating stability. This is the highest average power ever produced by a microwave tube in the millimeter wave region. A description of the gyrotron design and test results are presented

  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. 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.

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

    International Nuclear Information System (INIS)

    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

  10. Accurate frequency measurements on gyrotrons using a ''gyro-radiometer''

    International Nuclear Information System (INIS)

    Rebuffi, L.

    1986-08-01

    Using an heterodyne system, called ''Gyro-radiometer'', accurated frequency measurements have been carried out on VARIAN 60 GHz gyrotrons. Changing the principal tuning parameters of a gyrotron, we have detected frequency variations up to 100 MHz, ∼ 40 MHz frequency jumps and smaller jumps (∼ 10 MHz) when mismatches in the transmission line were present. FWHM bandwidth of 300 KHz, parasitic frequencies and frequency drift during 100 msec pulses have also been observed. An efficient method to find a stable-, high power-, long pulse-working point of a gyrotron loaded by a transmission line, has been derived. In general, for any power value it is possible to find stable working conditions tuning the principal parameters of the tube in correspondance of a maximum of the emitted frequency

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

    International Nuclear Information System (INIS)

    Lohr, J.; Calahan, P.; Callis, R.W.

    1999-01-01

    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

  12. Innovation on high-power long-pulse gyrotrons

    International Nuclear Information System (INIS)

    Litvak, Alexander; Sakamoto, Keishi; Thumm, Manfred

    2011-01-01

    Progress in the worldwide development of high-power gyrotrons for magnetic confinement fusion plasma applications is described. After technology breakthroughs in research on gyrotron components in the 1990s, significant progress has been achieved in the last decade, in particular, in the field of long-pulse and continuous wave (CW) gyrotrons for a wide range of frequencies. At present, the development of 1 MW-class CW gyrotrons has been very successful; these are applicable for self-ignition experiments on fusion plasmas and their confinement in the tokamak ITER, for long-pulse confinement experiments in the stellarator Wendelstein 7-X (W7-X) and for EC H and CD in the future tokamak JT-60SA. For this progress in the field of high-power long-pulse gyrotrons, innovations such as the realization of high-efficiency stable oscillation in very high order cavity modes, the use of single-stage depressed collectors for energy recovery, highly efficient internal quasi-optical mode converters and synthetic diamond windows have essentially contributed. The total tube efficiencies are around 50% and the purity of the fundamental Gaussian output mode is 97% and higher. In addition, activities for advanced gyrotrons, e.g. a 2 MW gyrotron using a coaxial cavity, multi-frequency 1 MW gyrotrons and power modulation technology, have made progress.

  13. 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.

  14. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Directory of Open Access Journals (Sweden)

    Andrew Oliphant

    Full Text Available Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C. We conclude that at settlement P. varians juveniles do not follow the temperature-size rule

  15. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Science.gov (United States)

    Oliphant, Andrew; Hauton, Chris; Thatje, Sven

    2013-01-01

    Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures) and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight) became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C). We conclude that at settlement P. varians juveniles do not follow the temperature-size rule; this is of

  16. Electron gun simulation for 95 GHz gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Udaybir; Kumar, Nitin; Sinha, A.K., E-mail: uday.ceeri@gmail.com, E-mail: aksinha@ceeri.ernet.in [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute, Pilani (India); Purohit, L.P. [Department of Physics, Gurukul Kangri Vishwavidyalaya, Haridwar (India)

    2011-07-01

    A triode type Magnetron Injection Gun (MIG) for a 2 MW, 95 GHz Gyrotron has been designed by using commercially available code EGUN and another in-house developed code MIGANS. The operating mode of the gyrotron is TE{sub 24.8} and it is operated in the fundamental harmonic. The operating voltages of the modulating anode and the accelerating anode are 61 kV and 85 kV respectively. The parametric dependences of modulating anode voltage and cathode magnetic field on the beam quality have also been studied. (author)

  17. Electron gun simulation for 95 GHz gyrotron

    International Nuclear Information System (INIS)

    Singh, Udaybir; Kumar, Nitin; Sinha, A.K.; Purohit, L.P.

    2011-01-01

    A triode type Magnetron Injection Gun (MIG) for a 2 MW, 95 GHz Gyrotron has been designed by using commercially available code EGUN and another in-house developed code MIGANS. The operating mode of the gyrotron is TE 24.8 and it is operated in the fundamental harmonic. The operating voltages of the modulating anode and the accelerating anode are 61 kV and 85 kV respectively. The parametric dependences of modulating anode voltage and cathode magnetic field on the beam quality have also been studied. (author)

  18. 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.

  19. Electron beam instabilities in gyrotron beam tunnels

    International Nuclear Information System (INIS)

    Pedrozzi, M.; Alberti, S.; Hogge, J.P.; Tran, M.Q.; Tran, T.M.

    1997-10-01

    Electron beam instabilities occurring in a gyrotron electron beam can induce an energy spread which might significantly deteriorate the gyrotron efficiency. Three types of instabilities are considered to explain the important discrepancy found between the theoretical and experimental efficiency in the case of quasi-optical gyrotrons (QOG): the electron cyclotron maser instability, the Bernstein instability and the Langmuir instability. The low magnetic field gradient in drift tubes of QOG makes that the electron cyclotron maser instability can develop in the drift tube at very low electron beam currents. Experimental measurements show that with a proper choice of absorbing structures in the beam tunnel, this instability can be suppressed. At high beam currents, the electrostatic Bernstein instability can induce a significant energy spread at the entrance of the interaction region. The induced energy spread scales approximately linearly with the electron beam density and for QOG one observes that the beam density is significantly higher than the beam density of an equivalent cylindrical cavity gyrotron. (author) figs., tabs., refs

  20. A 2 MW, CW, 170 GHz gyrotron for ITER

    International Nuclear Information System (INIS)

    Piosczyk, B.; Arnold, A.; Alberti, S.

    2003-01-01

    A 140 GHz gyrotron for CW operation is under development for the stellarator W7-X. With a prototype tube a microwave output power of about 0.9 MW has been obtained in pulses up to 180 s, limited by the capability of the high voltage power supply. The development work on coaxial cavity gyrotrons has demonstrated the feasibility of manufacturing of a 2 MW, CW 170 GHz tube that could be used for ITER. The problems specific to the coaxial arrangement have been investigated and all relevant information needed for an industrial realization of a coaxial gyrotron have been obtained in short pulse experiments (up to 17 ms). The suitability of critical components for a 2 MW, CW coaxial gyrotron has been studied and a first integrated design has been done. (author)

  1. Quasi-optical internal mode converters for 110 GHz gyrotrons

    International Nuclear Information System (INIS)

    Harper, B.M.; Lorbeck, J.A.; Vernon, R.J.

    1995-01-01

    Many early gyrotrons had a microwave output in the same mode that was produced in the microwave cavity, e.g. the TE 02 mode. These modes were often converted outside of the tube to a more desirable mode for plasma heating using a system of perturbed-wall waveguide mode converters. The current generation of gyrotrons commonly have cavity modes with a high azimuthal index, such as the rotating TE 22,6 mode. Mode conversion by means of waveguide mode converters is not usually practical for such cases. However, an output of a Gaussian beam or other desirable field pattern can be obtained by using a Vlasov-type launcher feeding a series of two or more reflectors. This system may be placed outside or inside of the gyrotron but there are advantages to placing it within the tube, e.g. allowing for a larger collector and smaller reflectors. When such a converter system is placed inside the gyrotron, it is usually preferable to use a modification to the simple Vlasov launcher such as the Denisov-type launcher, which incorporates a series of perturbations within it. The authors have designed both internal and external versions of such quasi-optical converters. They discuss an internal converter which was designed for use inside of a Varian 110 GHz gyrotron producing the TE 22,6 cavity mode. This design consists of four reflectors which are fed by a Denisov-type launcher. Design techniques for the reflector system are discussed and experimental results are presented

  2. The 140 GHZ, 1 MW Gyrotron - Status and Recent Results

    Science.gov (United States)

    Gantenbein, G.; Dammertz, G.; Illy, S.; Kern, S.; Leonhardt, W.; Piosczyk, B.; Schmid, M.; Thumm, M.; Braune, H.; Erckmann, V.; Laqua, H. P.; Michel, G.; Kasparek, W.; Lechte, C.; Legrand, F.; Lievin, C.; Prinz, O.

    2009-04-01

    A 10 MW ECRH system is currently under construction for the stellarator W7-X which will be built up and operated by IPP in Greifswald, Germany. The present status of the complete system is reported in [1]. The RF power will be provided by 10 gyrotrons. A European collaboration has been established to develop and build the 10 gyrotrons each with an output power of 1 MW for continuous wave (CW) operation [2]. Nine gyrotrons are being manufactured by Thales Electron Devices (TED), Vélizy, France, one gyrotron was produced by CPI, Palo Alto, CA and passed the acceptance tests at IPP. The acceptance tests of the TED gyrotrons are performed at the test stand at FZK and on site at IPP. The first series tube yielded a total output power of 0.98 MW, with an efficiency of 31 % (without a single stage depressed collector) in short pulse operation and of 0.92 MW in pulses of 1800 s (efficiency of almost 45 % at a depression voltage of 29 kV) [3], The Gaussian mode output power was 0.91 MW. The RF power, measured in a calorimetric load at the end of a 25 m long quasi-optical transmission line with seven mirrors, was 0.87 MW. In this contribution typical results of the next series gyrotrons will be reported.

  3. Microwave generation for magnetic fusion energy applications: Task A -- Experimental and numerical study of microwave sources for ECRH incorporating depressed collectors and with ITER-relevant parameters, and Task B -- Theory and modeling of high frequency, high power gyrotron operation. Final report, July 15, 1994--July 14, 1995

    International Nuclear Information System (INIS)

    1995-01-01

    A proof-of-principle short pulse (∼ 100 ns) experiment has successfully demonstrated operation of a sheet-beam FEL amplifier with output power of 250 kW at 86 Ghz and with 24 dB saturated gain and ∼ 3% efficiency. Gain in the linear region was 30 dB. Measured performance parameters were in good agreement with predictions of a multi-mode, time dependence code. Also, a code has been developed to design depressed collectors which will enhance efficiency of ECRH sources (both FELs and gyrotrons). Extensive analytical and theoretical work in support of high power gyrotron development at Varian and MIT, and in support of ITER has been carried out. Specific studies are described. The effect of beam quality on the operation of the 145 GHz gyrotrons at MIT has been characterized using experimentally measured beam velocity distribution functions. The observed performance of these devices is consistent with a 10% RMS perpendicular velocity spread. An extensive study of mode competition in the 110 GHZ experiments at Varian and MIT has been carried out. Design criteria for the suppression of parasitic modes have been given for these experiments. The issues of mode competition and beam quality in the proposed 170 GHz megawatt gyrotrons for ITER have been investigated. Designs of cavities which eliminate unwanted modes have been made, and their sensitivity to beam quality studied. The constraints of lower power density and absence of mode competition coupled with the anticipated beam quality restrict efficiency. Efficiency can be improved by increasing the power density in the wall, improving beam quality, or perhaps by using a more advanced cavity. Studies of the causes of velocity spread in MIG guns have been initiated. Further, the effect of beam cavity misalignment on mode competition has been addressed

  4. Improved Collectors for High Power Gyrotrons

    International Nuclear Information System (INIS)

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

    2009-01-01

    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.

  5. High power gyrotrons: a close perspective

    International Nuclear Information System (INIS)

    Kartikeyan, M.V.

    2012-01-01

    Gyrotrons and their variants, popularly known as gyrodevices are millimetric wave sources provide very high powers ranging from long pulse to continuous wave (CW) for various technological, scientific and industrial applications. From their conception (monotron-version) in the late fifties until their successful development for various applications, these devices have come a long way technologically and made an irreversible impact on both users and developers. The possible applications of high power millimeter and sub-millimeter waves from gyrotrons and their variants (gyro-devices) span a wide range of technologies. The plasma physics community has already taken advantage of the recent advances of gyrotrons 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 lower hybrid current drive (LHCD) (8 GHz), electron cyclotron resonance heating (ECRH) (28-170-220 GHz), electron cyclotron current drive (ECCD), collective Thomson scattering (CTS), heat-wave propagation experiments, and space-power grid (SPG) applications. Other important applications of gyrotrons are electron cyclotron resonance (ECR) discharges for the generation of multi- charged ions and soft X-rays, as well as industrial materials processing and plasma chemistry. Submillimeter wave gyrotrons are employed in high frequency, broadband electron paramagnetic resonance (EPR) spectroscopy. Additional future applications await the development of novel high power gyro-amplifiers and devices for high resolution radar ranging and imaging in atmospheric and planetary science as well as deep space and specialized satellite communications, RF drivers for next generation high gradient linear accelerators (supercolliders), high resolution Doppler radar, radar ranging and imaging in atmospheric and planetary science, drivers for next-generation high-gradient linear accelerators

  6. Chaos in high-power high-frequency gyrotrons

    International Nuclear Information System (INIS)

    Airila, M.

    2004-01-01

    Gyrotron interaction is a complex nonlinear dynamical process, which may turn chaotic in certain circumstances. The emergence of chaos renders dynamical systems unpredictable and causes bandwidth broadening of signals. Such effects would jeopardize the prospect of advanced gyrotrons in fusion. Therefore, it is important to be aware of the possibility of chaos in gyrotrons. There are three different chaos scenarios closely related to the development of high-power gyrotrons: First, the onset of chaos in electron trajectories would lead to difficulties in the design and efficient operation of depressed potential collectors, which are used for efficiency enhancement. Second, the radio-frequency signal could turn chaotic, decreasing the output power and the spectral purity of the output signal. As a result, mode conversion, transmission, and absorption efficiencies would be reduced. Third, spatio-temporal chaos in the resonator field structure can set a limit for the use of large-diameter interaction cavities and high-order TE modes (large azimuthal index) allowing higher generated power. In this thesis, the issues above are addressed with numerical modeling. It is found that chaos in electron residual energies is practically absent in the parameter region corresponding to high efficiency. Accordingly, depressed collectors are a feasible solution also in advanced high-power gyrotrons. A new method is presented for straightforward numerical solution of the one-dimensional self-consistent time-dependent gyrotron equations, and the method is generalized to two dimensions. In 1D, a chart of gyrotron oscillations is calculated. It is shown that the regions of stationary oscillations, automodulation, and chaos have a complicated topology in the plane of generalized gyrotron variables. The threshold current for chaotic oscillations exceeds typical operating currents by a factor of ten. However, reflection of the output signal may significantly lower the threshold. 2D

  7. Perspective gyrotron with mode converter for co- and counter-rotation operating modes

    International Nuclear Information System (INIS)

    Chirkov, A. V.; Kuftin, A. N.; Denisov, G. G.

    2015-01-01

    A gyrotron oscillator operating efficiently at modes of both rotations was developed and tested. The gyrotron operation can be switched between two modes: co- and counter rotating ones with respect to electron rotation in a resonance magnetic field. A synthesized mode converter provides output of both waves in the form of two different paraxial wave beams corresponding to direction of the mode rotation. Measured gyrotron power (up to 2 MW), interaction efficiency (34%), and diffraction losses in the mode converter (≈2%) agree well with the design values. The proposed gyrotron scheme alloys principal enhancement in the device parameters—possibility of electronic switching of output wave beam direction and possibility to arrange an effective scheme to provide frequency/phase locking of a gyrotron-oscillator

  8. Perspective gyrotron with mode converter for co- and counter-rotation operating modes

    Energy Technology Data Exchange (ETDEWEB)

    Chirkov, A. V.; Kuftin, A. N. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ul' yanov Street, 603950 Nizhny Novgorod (Russian Federation); Denisov, G. G. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ul' yanov Street, 603950 Nizhny Novgorod (Russian Federation); University of Nizhny Novgorod, 23 Prospekt Gagarina, 603950 Nizhny Novgorod (Russian Federation)

    2015-06-29

    A gyrotron oscillator operating efficiently at modes of both rotations was developed and tested. The gyrotron operation can be switched between two modes: co- and counter rotating ones with respect to electron rotation in a resonance magnetic field. A synthesized mode converter provides output of both waves in the form of two different paraxial wave beams corresponding to direction of the mode rotation. Measured gyrotron power (up to 2 MW), interaction efficiency (34%), and diffraction losses in the mode converter (≈2%) agree well with the design values. The proposed gyrotron scheme alloys principal enhancement in the device parameters—possibility of electronic switching of output wave beam direction and possibility to arrange an effective scheme to provide frequency/phase locking of a gyrotron-oscillator.

  9. Integrated Design of Undepressed Collector for Low Power Gyrotron

    Science.gov (United States)

    Kumar, Anil; Goswami, Uttam K.; Poonia, Sunita; Singh, Udaybir; Kumar, Nitin; Alaria, M. K.; Bera, A.; Khatun, Hasina; Sinha, A. K.

    2011-06-01

    A 42 GHz, 200 kW continuous wave (CW) gyrotron, operating at TE03 mode is under development for the electron cyclotron resonance plasma heating of the Indian TOKAMAK system. The gyrotron is made up of an undepressed collector. The undepressed collector is simple to design and cost effective. In this paper, a detailed design study of the undepressed collector for the 42 GHz gyrotron is presented. The EGUN code is used to analyze the spent electron beam trajectory for the maximum spread to reduce the power loading on the collector surface. To achieve wall loading ≤1 kW/cm2, a collector with a length of 800 mm and a radius of 42.5 mm is designed. The design also includes the three magnet systems around the collector for maximum and uniform beam spread. The thermal and the structural analyses are done using the ANSYS code to optimize the collector structure and dimensions with tolerance.

  10. SU-E-T-317: The Development of a DIBH Technique for Left Sided Breast Patients Undergoing Radiation Therapy Utilizing Varians RPM System in a Community Hospital

    International Nuclear Information System (INIS)

    Hasson, B; Young, M; Workie, D; Geraghty, C

    2014-01-01

    Purpose: To develop and implement a Deep Inhalation Breath Hold program (DIBH) for treatment of patients with Left-sided breast cancer in a community hospital. Methods: All patients with left sided breast cancer underwent a screening free breathing CT. Evaluation of the conventional tangent treatment fields and the heart was conducted. If the heart would not be excluded using tangents, the patient then received DIBH breathe coaching. The patients returned for a 4D CT simulation. The patients breathing cycle was monitored using the Varian Real-Time position ManagementTM (RPM) system to assess duration of DIBH, amplitude, phase and recovery time to normal breathing. Then a DIBH CT was obtained at the desired amplitude. Duplicate plans were developed for both free breathing and DIBH on the Eclipse planning system and comparison DVH's were created. The plan that provided the prescribed treatment coverage and the least doses to the OAR (heart, Lt. Lung) was determined. Those patients selected to receive treatment with DIBH were set up for treatment, and breathing was monitored using the RPM system. Practice trials were used to confirm that the amplitude, phase and recovery were consistent with findings from simulation. Results: 10 patients have been treated using the DIBH procedure in our clinic. The DIBH patients had an average increase of 80% lung volume on DIBH, decreased lung volume receiving 50% of the dose, and decreases in the V20 dose. Significant reduction in the maximum and mean dose to the heart, as well as the dose to 1CC of the volume for the DIBH plans. Conclusion: Using the RPM system already available in the clinic, staff training, and patient coaching a simple DIBH program was setup. The use of DIBH has shown promise in reducing doses to the critical organs while maintaining PTV coverage for left sided breast treatments

  11. SU-E-T-317: The Development of a DIBH Technique for Left Sided Breast Patients Undergoing Radiation Therapy Utilizing Varians RPM System in a Community Hospital

    Energy Technology Data Exchange (ETDEWEB)

    Hasson, B; Young, M; Workie, D; Geraghty, C [Anne Arundel Medical Center, Annapolis, MD (United States)

    2014-06-01

    Purpose: To develop and implement a Deep Inhalation Breath Hold program (DIBH) for treatment of patients with Left-sided breast cancer in a community hospital. Methods: All patients with left sided breast cancer underwent a screening free breathing CT. Evaluation of the conventional tangent treatment fields and the heart was conducted. If the heart would not be excluded using tangents, the patient then received DIBH breathe coaching. The patients returned for a 4D CT simulation. The patients breathing cycle was monitored using the Varian Real-Time position ManagementTM (RPM) system to assess duration of DIBH, amplitude, phase and recovery time to normal breathing. Then a DIBH CT was obtained at the desired amplitude. Duplicate plans were developed for both free breathing and DIBH on the Eclipse planning system and comparison DVH's were created. The plan that provided the prescribed treatment coverage and the least doses to the OAR (heart, Lt. Lung) was determined. Those patients selected to receive treatment with DIBH were set up for treatment, and breathing was monitored using the RPM system. Practice trials were used to confirm that the amplitude, phase and recovery were consistent with findings from simulation. Results: 10 patients have been treated using the DIBH procedure in our clinic. The DIBH patients had an average increase of 80% lung volume on DIBH, decreased lung volume receiving 50% of the dose, and decreases in the V20 dose. Significant reduction in the maximum and mean dose to the heart, as well as the dose to 1CC of the volume for the DIBH plans. Conclusion: Using the RPM system already available in the clinic, staff training, and patient coaching a simple DIBH program was setup. The use of DIBH has shown promise in reducing doses to the critical organs while maintaining PTV coverage for left sided breast treatments.

  12. Study of the parasitic oscillations in a gyrotron; Etudes des oscillations parasites dans un gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Pedrozzi, M. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1997-01-01

    This work is dedicated to the study of parasitic instabilities in a gyrotron, and to the influence of such instabilities on the interaction efficiency. The gyrotron is a high-power millimeter wave radiation source, based on the resonant interaction between a weakly relativistic electron beam immersed in a guiding magnetic field, and an electromagnetic wave. The gyrotron investigated here operates at a frequency close to 100 GHz: its main feature is that it is quasi optical. In this configuration, the electron beam interacts with a high order TEM eigenmode of a Fabry-Perot resonator, the axis of which is perpendicular to the electron beam path. During the development of this source, the highest efficiency that was achieved is approximately 30% lower than the theoretical predictions. At the same time, parasitic oscillations at frequencies close to the maximum relativistic cyclotronic frequency are detected. The power associated with these oscillations ranges from a few watts to a few kilowatts, with threshold currents of the order of 100 mA. It is suspected that the excitation of parasitic oscillations in the beam duct section before the interaction region might have a dramatic effect on the electron beam distribution function inducing, in particular, an energy spread. The cyclotron maser instability responsible for the energy exchange between particles and fields in a gyrotron, is very sensitive to energy spreads. It is thus necessary to identify the origin of the parasitic radiation. A few physical mechanisms suspected to lead to a degradation of the electron beam properties were investigated: the cyclotron maser process itself, the Bernstein electrostatic instability and the Langmuir instability. The experimental work concentrated on the study of the beam ducts between the electron gun and the resonant cavity. (author) figs., tabs., 90 refs.

  13. Single-stage depressed collectors for gyrotrons

    International Nuclear Information System (INIS)

    Piosczyk, B.; Iatrou, C.T.; Dammertz, G.; Thumm, M.; Univ. Karlsruhe

    1996-01-01

    Two 140 GHz gyrotrons with a single-step depressed collector have been operated. The different position of the isolating collector gap in the stray magnetic field causes the electron motion in the retarding region to be in one case adiabatic and in the other case nonadiabatic. The kind of motion within the retarding field influences strongly the behavior of the gyrotron with a depressed collector. In the case of nonadiabatic motion a significant amount of transverse momentum is given to the electrons reflected at the collector potential. This causes the reflected electrons to be trapped between the magnetic mirror and the collector. The electrons escape from the trap by diffusion across the magnetic field to the body of the tube thus contributing to the body current. Despite the high body current there is no observable influence of the collector voltage on the RF output power. In the case of adiabatic motion the reflected electrons do not gain a sufficient amount of transverse momentum to be trapped by the magnetic mirror. They pass the cavity toward the gun and they are trapped between the negative gun potential and the collector. The interaction with the RF field by electrons traveling through the cavity enhances the diffusion in the velocity space thus enabling the trapped electrons to overcome the potential barrier and escape toward the collector. Therefore the body current stays at low values since in this case the reflected electrons do not contribute to it. However, at higher collector voltages a reduction of RF power occurred and some noise in the electron beam was observed. The main motivation for the development of gyrotrons in the frequency range above 100 GHz with power levels in excess of several hundreds kW per tube, is the application in magnetic fusion devices for plasma heating and for electron current drive

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

    Energy Technology Data Exchange (ETDEWEB)

    Piosczyk, B [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM), Postfach 3640, D-76021 Karlsruhe (Germany); Dammertz, G [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM), Postfach 3640, D-76021 Karlsruhe (Germany); Dumbrajs, O [Department of Engineering Physics and Mathematics, Helsinki University of Technology, Association EURATOM-TEKES, FIN-02150 Espoo (Finland)] (and others)

    2005-01-01

    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 ({approx} 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.

  15. Electron beam emission and interaction of double-beam gyrotron

    International Nuclear Information System (INIS)

    Singh, Udaybir; Kumar, Anil; Kumar, Nitin; Kumar, Narendra; Pratap, Bhanu; Purohit, L.P.; Sinha, A.K.

    2012-01-01

    Highlights: ► The complete electrical design of electron gun and interaction structure of double-beam gyrotron. ► EGUN code is used for the simulation of electron gun of double-beam gyrotron. ► MAGIC code is used for the simulation of interaction structure of double-beam gyrotron. ► Design validations with other codes. - Abstract: This paper presents the numerical simulation of a double-beam magnetron injection gun (DB-MIG) and beam-wave interaction for 60 GHz, 500 kW gyrotron. The beam-wave interaction calculations, power and frequency growth estimation are performed by using PIC code MAGIC. The maximum output power of 510 kW at 41.5% efficiency, beam currents of 6 A and 12 A, electron beam velocity ratios of 1.41 and 1.25 and beam voltage of 69 kV are estimated. To obtain the design parameters, the DB-MIG with maximum transverse velocity spread less than 5% is designed. The computer simulations are performed by using the commercially available code EGUN and the in-house developed code MIGANS. The simulated results of DB-MIG design obtained by using the EGUN code are also validated with another trajectory code TRAK, which are in good agreement.

  16. Electron beam emission and interaction of double-beam gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Udaybir, E-mail: uday.ceeri@gmail.com [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute (CEERI), Council of Scientific and Industrial Research (CSIR), Pilani, Rajasthan 333031 (India); Department of Physics, Gurukul Kangri University, Haridwar 249404 (India); Kumar, Anil [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute (CEERI), Council of Scientific and Industrial Research (CSIR), Pilani, Rajasthan 333031 (India); Kumar, Nitin, E-mail: nitin_physika@rediffmail.com [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute (CEERI), Council of Scientific and Industrial Research (CSIR), Pilani, Rajasthan 333031 (India); Kumar, Narendra; Pratap, Bhanu [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute (CEERI), Council of Scientific and Industrial Research (CSIR), Pilani, Rajasthan 333031 (India); Purohit, L.P. [Department of Physics, Gurukul Kangri University, Haridwar 249404 (India); Sinha, A.K., E-mail: aksinha@ceeri.ernet.in [Gyrotron Laboratory, Microwave Tube Area, Central Electronics Engineering Research Institute (CEERI), Council of Scientific and Industrial Research (CSIR), Pilani, Rajasthan 333031 (India)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The complete electrical design of electron gun and interaction structure of double-beam gyrotron. Black-Right-Pointing-Pointer EGUN code is used for the simulation of electron gun of double-beam gyrotron. Black-Right-Pointing-Pointer MAGIC code is used for the simulation of interaction structure of double-beam gyrotron. Black-Right-Pointing-Pointer Design validations with other codes. - Abstract: This paper presents the numerical simulation of a double-beam magnetron injection gun (DB-MIG) and beam-wave interaction for 60 GHz, 500 kW gyrotron. The beam-wave interaction calculations, power and frequency growth estimation are performed by using PIC code MAGIC. The maximum output power of 510 kW at 41.5% efficiency, beam currents of 6 A and 12 A, electron beam velocity ratios of 1.41 and 1.25 and beam voltage of 69 kV are estimated. To obtain the design parameters, the DB-MIG with maximum transverse velocity spread less than 5% is designed. The computer simulations are performed by using the commercially available code EGUN and the in-house developed code MIGANS. The simulated results of DB-MIG design obtained by using the EGUN code are also validated with another trajectory code TRAK, which are in good agreement.

  17. Time-dependent spectrum analysis of high power gyrotrons

    International Nuclear Information System (INIS)

    Schlaich, Andreas

    2015-01-01

    In this work, an investigation of vacuum electronic oscillators capable of generating multi-megawatt continuous wave output power in the millimeter-wave range (so-called gyrotrons) through spectral measurements is presented. The centerpiece is the development of a measurement system with a high dynamic range (50-60 dB) for time-dependent spectrum analysis, covering the frequency range 100-170 GHz with instantaneous bandwidths of 6-12 GHz. Despite relying on heterodyne reception through harmonic mixers, the Pulse Spectrum Analysis (PSA) system maintains RF unambiguity in the spectrogram output through the application of a novel RF reconstruction technique. Using the new possibilities, a wide range of spectral phenomena in gyrotrons has been investigated, such as cavity mode jumps, lowfrequency modulation, frequency tuning in long pulses and the spectral behavior during the presence of an RF window arc. A dedicated investigation on parasitic RF oscillations in W7-X gyrotrons combining several analysis techniques led to the conclusion that after-cavity oscillations can be physical reality in high power gyrotrons, and are the probable cause for the undesired signals observed. Apart from systematic parameter sweeps using the PSA system, an analytical dispersion analysis in the Brillouin diagram was applied, and numerical gyrotron interaction simulations of unprecedented extent were conducted. Furthermore, the improved frequency measurement capabilities were employed to analyze the frequency tuning through thermal expansion and electrostatic neutralization caused by ionization inside the tube in long-pulse operation. By macroscopically modeling the gas dynamics and ionization processes in combination with a fitting process, the time dependences of the two processes could be investigated. In doing so, indication was found that the neutralization in W7-X gyrotrons amounts to only 60% of the electrostatic depression voltage, instead of 100% as widely believed for

  18. Time-dependent spectrum analysis of high power gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Schlaich, Andreas

    2015-07-01

    In this work, an investigation of vacuum electronic oscillators capable of generating multi-megawatt continuous wave output power in the millimeter-wave range (so-called gyrotrons) through spectral measurements is presented. The centerpiece is the development of a measurement system with a high dynamic range (50-60 dB) for time-dependent spectrum analysis, covering the frequency range 100-170 GHz with instantaneous bandwidths of 6-12 GHz. Despite relying on heterodyne reception through harmonic mixers, the Pulse Spectrum Analysis (PSA) system maintains RF unambiguity in the spectrogram output through the application of a novel RF reconstruction technique. Using the new possibilities, a wide range of spectral phenomena in gyrotrons has been investigated, such as cavity mode jumps, lowfrequency modulation, frequency tuning in long pulses and the spectral behavior during the presence of an RF window arc. A dedicated investigation on parasitic RF oscillations in W7-X gyrotrons combining several analysis techniques led to the conclusion that after-cavity oscillations can be physical reality in high power gyrotrons, and are the probable cause for the undesired signals observed. Apart from systematic parameter sweeps using the PSA system, an analytical dispersion analysis in the Brillouin diagram was applied, and numerical gyrotron interaction simulations of unprecedented extent were conducted. Furthermore, the improved frequency measurement capabilities were employed to analyze the frequency tuning through thermal expansion and electrostatic neutralization caused by ionization inside the tube in long-pulse operation. By macroscopically modeling the gas dynamics and ionization processes in combination with a fitting process, the time dependences of the two processes could be investigated. In doing so, indication was found that the neutralization in W7-X gyrotrons amounts to only 60% of the electrostatic depression voltage, instead of 100% as widely believed for

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

    International Nuclear Information System (INIS)

    Ferguson, S.W.; Felker, B.; Jackson, M.C.; Petersen, D.E.; Sewall, N.R.; Stever, R.D.

    1991-09-01

    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

  20. The MTX computer control system for the 400 kilowatt 140 GHz gyrotron

    International Nuclear Information System (INIS)

    Jackson, M.C.; Ferguson, S.W.; Petersen, D.E.

    1991-09-01

    A 400 kilowatt, 140 Ghz gyrotron is employed on MTX as a source of direct plasma heating and, additionally, as a driver for a free electron laser, which is used for plasma heating. The control system that operates this gyrotron uses a new graphics oriented software system called TACL (Thaumaturgic Automated Control Logic) developed by the Continuous Electron Beam Accelerator Facility (CEBAF) and owned by DOE. This control language does not require a software specialist, but is easily handled by the engineer or technician working on the system. All control logic and custom displays are entered via graphics oriented editors and no actual lines of code need to be written. The graphics displays make the gyrotron operation quite simple and allow individual users to define displays to meet their own needs or develop one for a specific set of tests to be run. The system, additionally, can be used for logging functions, which have been found quite useful in tracking long term trends in vacion current and calorimetry of gyrotron cooling circuits. The system is composed of one computer (HP 9000 series 300) controlling multiple CAMAC crates located at the various components used in the system. A second series 300 computer is used as a supervisor and is located in the main tokamak control room. This supervisory computer provides remote operation of the gyrotron, and also provides a link to the microwave transport vacuum control (also TACL). The supervisory computer, additionally, is used as a subsystem status summary point for permissives to the gyrotron control system

  1. Analysis of a prototype of a novel 1.5 MW, 170 GHz coaxial cavity gyrotron

    International Nuclear Information System (INIS)

    Rzesnicki, T.

    2007-06-01

    A 170 GHz, 2 MW coaxial cavity gyrotron is under development at the Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM) at Forschungszentrum Karlsruhe (FZK) which will be used as a high power microwave source for heating, current drive and stability control of plasmas in the International Thermonuclear Experimental Reactor (ITER). At frequencies above about 100 GHz the output power of conventional gyrotrons with cylindrical hollow waveguide cavities is limited to 1 MW in CW operation mainly due to the high Ohmic losses and the space charge voltage depression of the electron beam. The coaxial geometry enables a reduction of the mode competition in the gyrotron resonator and decreases also the influence of the beam voltage depression. As result a very high order operating mode (for example TE34,19 at 170 GHz) can be chosen which ultimately allows to increase the output power of the gyrotron in CW operation to a value as high as 2 MW. A first prototype of the 170 GHz, 2 MW coaxial cavity gyrotron has been designed, built and experimentally tested in short pulse operation at FZK. The main goal of this work was to investigate experimentally the design of the critical gyrotron components such as electron gun, resonator and a quasi-optical RF system. Those components are same as used in the first industrial coaxial prototype gyrotron for ITER. During the experiments a strong instability was observed inside the gyrotron tube due to the excitation of parasitic low frequency oscillations. The mechanism of the oscillations has been studied and possibilities for their suppression of these oscillations are proposed and experimentally verified. The RF output system is one of the most critical components. It is responsible for the coupling of the gyrotron power out of the gyrotron by converting the microwave power generated in the TE 34,19 -mode into a fundamental free space TEM 0,0 ''Gaussian'' mode. The performance of the RF output system has been tested in low

  2. Advanced Output Coupling for High Power Gyrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Read, Michael [Calabazas Creek Research, Inc., San Mateo, CA (United States); Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Guss, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lohr, John [General Atomics, La Jolla, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States); Bui, Thuc [Calabazas Creek Research, Inc., San Mateo, CA (United States)

    2016-11-28

    The Phase II program developed an internal RF coupler that transforms the whispering gallery RF mode produced in gyrotron cavities to an HE11 waveguide mode propagating in corrugated waveguide. This power is extracted from the vacuum using a broadband, chemical vapor deposited (CVD) diamond, Brewster angle window capable of transmitting more than 1.5 MW CW of RF power over a broad range of frequencies. This coupling system eliminates the Mirror Optical Units now required to externally couple Gaussian output power into corrugated waveguide, significantly reducing system cost and increasing efficiency. The program simulated the performance using a broad range of advanced computer codes to optimize the design. Both a direct coupler and Brewster angle window were built and tested at low and high power. Test results confirmed the performance of both devices and demonstrated they are capable of achieving the required performance for scientific, defense, industrial, and medical applications.

  3. Suppression and nonlinear excitation of parasitic modes in second harmonic gyrotrons operating in a very high order mode

    International Nuclear Information System (INIS)

    Nusinovich, Gregory S.; Pu, Ruifeng; Granatstein, Victor L.

    2015-01-01

    In recent years, there was an active development of high-power, sub-terahertz (sub-THz) gyrotrons for numerous applications. For example, a 0.67 THz gyrotron delivering more than 200 kW with about 20% efficiency was developed. This record high efficiency was achieved because the gyrotron operated in a high-order TE 31,8 -mode with the power of ohmic losses less than 10% of the power of outgoing radiation. That gyrotron operated at the fundamental cyclotron resonance, and a high magnetic field of about 27 T was created by a pulse solenoid. For numerous applications, it is beneficial to use gyrotrons at cyclotron harmonics which can operate in available cryomagnets with fields not exceeding 15 T. However, typically, the gyrotron operation at harmonics faces severe competition from parasitic modes at the fundamental resonance. In the present paper, we consider a similar 0.67 THz gyrotron designed for operation in the same TE 31,8 -mode, but at the second harmonic. We focus on two nonlinear effects typical for interaction between the fundamental and second harmonic modes, viz., the mode suppression and the nonlinear excitation of the mode at the fundamental harmonic by the second harmonic oscillations. Our study includes both the analytical theory and numerical simulations performed with the self-consistent code MAGY. The simulations show that stable second harmonic operation in the TE 31,8 mode is possible with only modest sacrifice of efficiency and power

  4. Analytic theory of the gyrotron

    International Nuclear Information System (INIS)

    Lentini, P.J.

    1989-06-01

    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

  5. Synthesis of mig-type electron guns for gyrotrons

    International Nuclear Information System (INIS)

    Castro, J.J.B. de; Montes, A.; Silva, C.A.B.

    1984-01-01

    A synthesis method is used in the design of axially symmetrical guns in the moderate to high space charge regime. Self-consistent equations for the temperature limited emission case are used to represent the beam and solve the internal problem, under the requirement of laminar flow. The external problem is solved by integrating the equations with boundary conditions defined by the analytically extended solutions of the internal problem. This technique will be used in the development of INPE's gyrotron. (Author) [pt

  6. Gyrotrons for fusion. Status and prospects

    International Nuclear Information System (INIS)

    Litvak, A.G.; Alikaev, V.V.; Denisov, G.G.; Kurbatov, V.I.; Myasnikov, V.E.; Tai, E.M.; Zapevalov, V.E.

    2001-01-01

    Gyrotrons are the most advanced high-power sources of millimeter wavelength radiation. They have been used for many years in electron-cyclotron-wave (ECW) systems of many existing fusion installations. Typically modern gyrotrons produce power of 0.5...0.8 MW in pulses of 2-3 seconds, or lower power in longer pulses (e.g. 300-400 kW in pulses up to 10-15 seconds). For the next generation of fusion installations, such as ITER or W7-X the ECW systems based on gyrotrons capable to produce 1MW/CW radiation are considered. Definitely, such gyrotrons with enhanced performance are very interesting also for the use also at existing installations

  7. SU-E-T-406: Use of TrueBeam Developer Mode and API to Increase the Efficiency and Accuracy of Commissioning Measurements for the Varian EDGE Stereotactic Linac

    International Nuclear Information System (INIS)

    Gardner, S; Gulam, M; Song, K; Li, H; Huang, Y; Zhao, B; Qin, Y; Snyder, K; Kim, J; Gordon, J; Chetty, I; Wen, N

    2014-01-01

    Purpose: The Varian EDGE machine is a new stereotactic platform, combining Calypso and VisionRT localization systems with a stereotactic linac. The system includes TrueBeam DeveloperMode, making possible the use of XML-scripting for automation of linac-related tasks. This study details the use of DeveloperMode to automate commissioning tasks for Varian EDGE, thereby improving efficiency and measurement consistency. Methods: XML-scripting was used for various commissioning tasks,including couch model verification,beam-scanning,and isocenter verification. For couch measurements, point measurements were acquired for several field sizes (2×2,4×4,10×10cm 2 ) at 42 gantry angles for two couch-models. Measurements were acquired with variations in couch position(rails in/out,couch shifted in each of motion axes) compared to treatment planning system(TPS)-calculated values,which were logged automatically through advanced planning interface(API) scripting functionality. For beam scanning, XML-scripts were used to create custom MLC-apertures. For isocenter verification, XML-scripts were used to automate various Winston-Lutz-type tests. Results: For couch measurements, the time required for each set of angles was approximately 9 minutes. Without scripting, each set required approximately 12 minutes. Automated measurements required only one physicist, while manual measurements required at least two physicists to handle linac positions/beams and data recording. MLC apertures were generated outside of the TPS,and with the .xml file format, double-checking without use of TPS/operator console was possible. Similar time efficiency gains were found for isocenter verification measurements Conclusion: The use of XML scripting in TrueBeam DeveloperMode allows for efficient and accurate data acquisition during commissioning. The efficiency improvement is most pronounced for iterative measurements, exemplified by the time savings for couch modeling measurements(approximately 10 hours

  8. Modeling of mode purity in high power gyrotrons

    International Nuclear Information System (INIS)

    Cai, S.Y.; Antonsen, T.M. Jr.; Saraph, G.P.

    1993-01-01

    Spurious mode generation at the same frequency of the operational mode in a high power gyrotron can significantly reduce the power handling capability and the stability of a gyrotron oscillator because these modes are usually not matched at the output window and thus have high absorption and reflection rates. To study the generation of this kind of mode, the authors developed a numerical model based on an existing multimode self-consistent time-dependent computer code. This model includes both TE and TM modes and accounts for mode transformations due to the waveguide inhomogeneity. With this new tool, they study the mode transformation in the gyrotron and the possibility of excitation of parasitic TE and TM modes in the up taper section due to the gyroklystron mechanism. Their preliminary results show moderate excitation of both TE and TM modes at the same frequency as the main operating mode at locations near their cutoff. Details of the model and further simulation results will be presented

  9. Fast power measurement on a 30 GHz/15 kW gyrotron

    International Nuclear Information System (INIS)

    Saala, G.

    2004-09-01

    This work has been developed in the scope of a study-thesis at the Universitaet Karlsruhe (TH). The realization took place at the Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM) at the Forschungszentrum Karlsruhe (FZK). The aim was to investigate the possibilities of a fast power measurement at a compact, industrial gyrotron-system. To measure the output-power a small fraction of the gyrotron microwave radiation is coupled out and analyzed using a diode-detector. At the beginning of the work a mirror of the quasi-optical transmission line with a built in λ/4-coupler was available. This built-in coupler and other coupling structures which have been set up during this work have been characterized. To be able to perform reproduceable measurements several computer programs have been developed. Using these programs the gyrotron-system can be remote-controlled from a PC. The diode-detector signal has been analyzed under different conditions of gyrotron operation with respect to its short-term- and long-term-stability. After that the dependency of the calorimetrically measured output-power of the gyrotron has been used to calibrate the diode-voltage. (orig.)

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

    International Nuclear Information System (INIS)

    Caplan, M.

    1986-01-01

    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

  11. 100 GHz, 1 MW, CW gyrotron study program. Final report

    International Nuclear Information System (INIS)

    Felch, K.; Bier, R.; Caplan, M.; Jory, H.

    1983-09-01

    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

  12. The MTX computer control system for the 400 kilowatt 140 Ghz gyrotron

    International Nuclear Information System (INIS)

    Jackson, M.C.; Ferguson, S.W.; Petersen, D.E.

    1992-01-01

    This paper reports on a 400 kilowatt, 140 Ghz gyrotron employed on MTX as a source of direct plasma heating and, additionally, as a driver for a free electron laser, which is used for plasma heating. The control system that operates this gyrotron uses a new graphics oriented software system called TACL (Thaumaturgic Automated Control Logic) developed by the Continuous Electron Beam Accelerator Facility (CEBAF) and owned by DOE. This control language does not require a software specialist, but is easily handled by the engineer or technician working on the system. All control logic and custom displays are entered via graphics oriented editors and no actual lines of code need to be written. The graphics displays make the gyrotron operation quite simple and allow individual users to define displays to meet their own needs or develop one for a specific set of tests to be run. The system, additionally, can be used for data logging functions, which have been found quite useful in tracking long term trends in vacion current and calorimetry of gyrotron cooling circuits

  13. Interpretation of the nonlinear mode excitation in the ITER gyrotron

    International Nuclear Information System (INIS)

    Nusinovich, G. S.; Sinitsyn, O. V.

    2007-01-01

    This study was motivated by an interesting physical effect observed in experiments with a 1 MW, 170 GHz, continuous-wave gyrotron developed at the Japan Atomic Energy Agency for plasma heating and current drive in ITER [see, e.g., Fusion Eng. Des. 55, issues 2-3 (2001)]. In these experiments, the gyrotron switching from a parasitic mode to the operating one was observed with the increase in external magnetic field in the region of hard self-excitation of the operating mode where it cannot be excited from the noise level in the absence of other modes. Below, the theory describing this effect is developed. The switching mechanism caused by merging and disappearance of two (one stable and another unstable) equilibrium states with nonzero amplitudes of both modes is proposed. It is found that the present theory can correctly interpret experimental results qualitatively, but the lack of experimental data does not let the authors carry out some simulations more adequate to experimental conditions

  14. 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.

  15. Asymmetric modes in gyrotron tubes and their experimental study

    International Nuclear Information System (INIS)

    Garin, P.; Jedar, E.; Jendrzejczak, G.; mourier, G.; Payen, F.; Teyssier, L.

    1989-01-01

    High power gyrotron tubes suffer from the competition between oscillations on different modes of the resonant cavity. Different techniques for mode selection are outlined and the advantages of non symmetric modes are indicated. Their experimental study is described on a 100 GHz-200 kW - 100 ms - TE34 gyrotron. Some possible extrapolations are briefly presented. (author). 6 refs.; 4 figs

  16. Precision Characterization of Gyrotron Window Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Charles R. [North Carolina Central Univ., Durham, NC (United States)

    2012-12-31

    The response of dielectric material to electromagnetic waves in the millimeter wavelength range (30 to 300 GHz) has received relatively little study and the processes that give rise to absorption in this region are often poorly understood. Understanding the origin of absorption at these wavelengths has basic significance for solid state physics as well as importance for development of technology in this region of the RF spectrum. This project has provided high-quality data on the temperature dependence of the dielectric loss in high-purity, semi-insulating silicon carbide (HPSI SiC), a material that holds much promise for application, especially in devices that must operate in the high power and high frequency regime. Comparison of this experimental data with theoretical predictions for various loss processes provides convincing evidence that the loss in HPSI SiC arises almost entirely from intrinsic lattice loss (ILL) as described by Garin. Fitting the data to this model yields an accurate value for the Debye temperature that characterizes crystalline SiC. In addition, our results refute a previous study(2) which reported much higher loss, attributed to the presence of free charge. The quality of the data acquired in this project is clear evidence for the value of the experimental technique that was employed here. This technique combines the excitation of a high-quality open resonator by a phase-locked backward wave oscillator (BWO) with use of a spectrum analyzer to measure the change in the resonator response curve when the sample is inserted. This system has demonstrated consistent results for very challenging measurements and does not suffer from the artifacts that often arise when using other techniques that rely on thermal sources. The low absorption loss found in HPSI SiC, when combined with its other outstanding material properties, e.g. high thermal conductivity, high tensile strength, and high carrier mobility, should provide incentive for designers to

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

    International Nuclear Information System (INIS)

    Muggli, P.

    1991-11-01

    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 TE o 011 mode of the cavity. (author) figs., tabs., 102 refs

  18. Experimental study of a 1 MW, 170 GHz gyrotron oscillator

    Science.gov (United States)

    Kimura, Takuji

    A detailed experimental study is presented of a 1 MW, 170 GHz gyrotron oscillator whose design is consistent with the ECH requirements of the International Thermonuclear Experimental Reactor (ITER) for bulk heating and current drive. This work is the first to demonstrate that megawatt power level at 170 GHz can be achieved in a gyrotron with high efficiency for plasma heating applications. Maximum output power of 1.5 MW is obtained at 170.1 GHz in 85 kV, 50A operation for an efficiency of 35%. Although the experiment at MIT is conducted with short pulses (3 μs), the gyrotron is designed to be suitable for development by industry for continuous wave operation. The peak ohmic loss on the cavity wall for 1 MW of output power is calculated to be 2.3 kW/cm2, which can be handled using present cooling technology. Mode competition problems in a highly over-moded cavity are studied to maximize the efficiency. Various aspects of electron gun design are examined to obtain high quality electron beams with very low velocity spread. A triode magnetron injection gun is designed using the EGUN simulation code. A total perpendicular velocity spread of less than 8% is realized by designing a low- sensitivity, non-adiabatic gun. The RF power is generated in a short tapered cavity with an iris step. The operating mode is the TE28,8,1 mode. A mode converter is designed to convert the RF output to a Gaussian beam. Power and efficiency are measured in the design TE28,8,1 mode at 170.1 GHz as well as the TE27,8,1 mode at 166.6 GHz and TE29,8,1 mode at 173.5 GHz. Efficiencies between 34%-36% are consistently obtained over a wide range of operating parameters. These efficiencies agree with the highest values predicted by the multimode simulations. The startup scenario is investigated and observed to agree with the linear theory. The measured beam velocity ratio is consistent with EGUN simulation. Interception of reflected beam by the mod-anode is measured as a function of velocity ratio

  19. Local control unit for ITER-India gyrotron test facility (IIGTF)

    Energy Technology Data Exchange (ETDEWEB)

    Rathod, Vipal, E-mail: vipal.rathod@iter-india.org; Shah, Ronak; Mandge, Deepak; Parmar, Rajvi; Rao, S.L.

    2016-11-15

    Highlights: • A dedicated full scale ITER prototype Local Control Unit for ITER-India Gyrotron test facility. • National Instruments® make PXIe system for real time control & data acquisition and Siemens® PLC for sequence control function. • Hardwired FPGA based fast protection interlock system. • High speed analog fiber optical transmission link using V/F and F/V technique. • Software framework based on LabVIEW™ platform and ITER CODAC Core System. - Abstract: Electron Cyclotron system on ITER, is one of the important RF ancillary systems based on high power Gyrotron RF sources, that is used for plasma heating and current drive applications. To operate a Gyrotron source, various auxiliary systems and services such as Super Conducting Magnet set, High Voltage Power Supplies, Auxiliary Power Supplies, Waveguide components, Cooling water system and a Local Control Unit (LCU) are required. The LCU plays a very crucial role for the safe and reliable operation of Gyrotron system. A dedicated full scale ITER prototype LCU is being developed for testing and commissioning of an ITER like Test Gyrotron at ITER-India Gyrotron Test facility (IIGTF). The main functions of LCU include Sequence Control, Local Interlock Protection and Real Time Data Acquisition. PLC based slow controller is used for implementing the Sequence Control & Slow Interlock functions. Critical Protection Interlocks are required to have a response time of <10 μs and are implemented using custom built hardware and PXIe based fast controller. Also PXIe system is used for implementing Real Time Data Acquisition function that is required to have slow and fast acquisition with online visualization and off line analysis facility. A Signal Conditioning Unit (SCU) is used to interface and faithfully transmit the field signals to the remote control systems. Necessary controller hardware is procured and several pre-prototype developments have been taken up to establish the critical subsystems such as

  20. Local control unit for ITER-India gyrotron test facility (IIGTF)

    International Nuclear Information System (INIS)

    Rathod, Vipal; Shah, Ronak; Mandge, Deepak; Parmar, Rajvi; Rao, S.L.

    2016-01-01

    Highlights: • A dedicated full scale ITER prototype Local Control Unit for ITER-India Gyrotron test facility. • National Instruments® make PXIe system for real time control & data acquisition and Siemens® PLC for sequence control function. • Hardwired FPGA based fast protection interlock system. • High speed analog fiber optical transmission link using V/F and F/V technique. • Software framework based on LabVIEW™ platform and ITER CODAC Core System. - Abstract: Electron Cyclotron system on ITER, is one of the important RF ancillary systems based on high power Gyrotron RF sources, that is used for plasma heating and current drive applications. To operate a Gyrotron source, various auxiliary systems and services such as Super Conducting Magnet set, High Voltage Power Supplies, Auxiliary Power Supplies, Waveguide components, Cooling water system and a Local Control Unit (LCU) are required. The LCU plays a very crucial role for the safe and reliable operation of Gyrotron system. A dedicated full scale ITER prototype LCU is being developed for testing and commissioning of an ITER like Test Gyrotron at ITER-India Gyrotron Test facility (IIGTF). The main functions of LCU include Sequence Control, Local Interlock Protection and Real Time Data Acquisition. PLC based slow controller is used for implementing the Sequence Control & Slow Interlock functions. Critical Protection Interlocks are required to have a response time of <10 μs and are implemented using custom built hardware and PXIe based fast controller. Also PXIe system is used for implementing Real Time Data Acquisition function that is required to have slow and fast acquisition with online visualization and off line analysis facility. A Signal Conditioning Unit (SCU) is used to interface and faithfully transmit the field signals to the remote control systems. Necessary controller hardware is procured and several pre-prototype developments have been taken up to establish the critical subsystems such as

  1. Feasibility of a dual regime gyrotron

    International Nuclear Information System (INIS)

    Sawant, Ashwini; Jain, Prerit; Kartikeyan, M.V.

    2012-01-01

    The design concept of a 42/84 GHz, 500 kW, CW, dual-regime gyrotron for ECRH of plasma in an experimental Tokamak will be presented in this paper. Operation at 42 GHz is fundamental where as that in 84 GHz will be second harmonic so that a similar guidance system will be retained for dual regime operation. In this paper, the mode competition and mode selection procedures are presented for such a dual regime operation. Cold cavity design and self-consistent calculations will be carried out for power and efficiencies. (author)

  2. New window materials for high power gyrotron

    International Nuclear Information System (INIS)

    Afsar, M.N.; Hua Chi

    1993-01-01

    A single free standing synthetic diamond window seems to have higher absorption coefficient value at millimeter wavelength region at this time although it is claimed that it possesses good mechanical strength and higher thermal conductivity characteristics. It certainly does not rule out the use of diamond film on single crystal high resistivity silicon to improve its mechanical strength and thermal conductivity. One may have to use an appropriate film thickness for a particular wavelength in gyrotron window application. It is also necessary to use an appropriate thickness for the silicon perhaps equivalent to a quaterwavelength in order to avoid the reflection mismatch

  3. Suppression criteria of parasitic mode oscillations in a gyrotron beam tunnel

    Science.gov (United States)

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

    2011-02-01

    This paper presents the design criteria of the parasitic mode oscillations suppression for a periodic, ceramic, and copper loaded gyrotron beam tunnel. In such a type of beam tunnel, the suppression of parasitic mode oscillations is an important design problem. A method of beam-wave coupling coefficient and its mathematical formulation are presented. The developed design criteria are used in the beam tunnel design of a 42 GHz gyrotron to be developed for the Indian TOKAMAK system. The role of the thickness and the radius of the beam tunnel copper rings to obtain the developed design criteria are also discussed. The commercially available electromagnetic code CST and the electron trajectory code EGUN are used for the simulations.

  4. Suppression criteria of parasitic mode oscillations in a gyrotron beam tunnel

    International Nuclear Information System (INIS)

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

    2011-01-01

    This paper presents the design criteria of the parasitic mode oscillations suppression for a periodic, ceramic, and copper loaded gyrotron beam tunnel. In such a type of beam tunnel, the suppression of parasitic mode oscillations is an important design problem. A method of beam-wave coupling coefficient and its mathematical formulation are presented. The developed design criteria are used in the beam tunnel design of a 42 GHz gyrotron to be developed for the Indian TOKAMAK system. The role of the thickness and the radius of the beam tunnel copper rings to obtain the developed design criteria are also discussed. The commercially available electromagnetic code CST and the electron trajectory code EGUN are used for the simulations.

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

    International Nuclear Information System (INIS)

    Polevoy, J.T.

    1989-06-01

    Experimental measurements of the average axial velocity v parallel 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 V p and the beam current I b . V p is measured through the use of a capacitive probe installed near or within the gyrotron cavity, while I b 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 v parallel and calculations of the corresponding transverse to longitudinal beam velocity ratio α = v perpendicular /v parallel 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 v parallel 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

  6. [Porting Radiotherapy Software of Varian to Cloud Platform].

    Science.gov (United States)

    Zou, Lian; Zhang, Weisha; Liu, Xiangxiang; Xie, Zhao; Xie, Yaoqin

    2017-09-30

    To develop a low-cost private cloud platform of radiotherapy software. First, a private cloud platform which was based on OpenStack and the virtual GPU hardware was builded. Then on the private cloud platform, all the Varian radiotherapy software modules were installed to the virtual machine, and the corresponding function configuration was completed. Finally the software on the cloud was able to be accessed by virtual desktop client. The function test results of the cloud workstation show that a cloud workstation is equivalent to an isolated physical workstation, and any clients on the LAN can use the cloud workstation smoothly. The cloud platform transplantation in this study is economical and practical. The project not only improves the utilization rates of radiotherapy software, but also makes it possible that the cloud computing technology can expand its applications to the field of radiation oncology.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  8. Numerical Simulation of a Double-anode Magnetron Injection Gun for 110 GHz, 1 MW Gyrotron

    Science.gov (United States)

    Singh, Udaybir; Kumar, Nitin; Purohit, L. P.; Sinha, Ashok K.

    2010-07-01

    A 40 A double-anode magnetron injection gun for a 1 MW, 110 GHz gyrotron has been designed. The preliminary design has been obtained by using some trade-off equations. The electron beam analysis has been performed by using the commercially available code EGUN and the in-house developed code MIGANS. The operating mode of the gyrotron is TE22,6 and it is operated in the fundamental harmonic. The electron beam with a low transverse velocity spread ( δ {β_{ bot max }} = 2.26% ) and the transverse-to-axial velocity ratio of the electron beam (α) = 1.37 is obtained. The simulated results of the MIG obtained with the EGUN code have been validated with another trajectory code TRAK. The results on the design output parameters obtained by both the codes are in good agreement. The sensitivity analysis has been carried out by changing the different gun parameters to decide the fabrication tolerance.

  9. Experimental measurements on a 100 GHz frequency tunable quasioptical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Tran, M.Q.; Hogge, J.P.; Tran, T.M.; Bondeson, A.; Muggli, P.; Perrenoud, A.; Joedicke, B.; Mathews, H.G.

    1990-01-01

    Experiments on a 100 GHz quasioptical (QO) gyrotron operating at the fundamental (ω=Ω ce ) are described. Powers larger than 90 kW at an efficiency of about 12% were achieved. Depending on the electron beam parameters, the frequency spectrum of the output can be either single moded or multimoded. One of the main advantages of the QO gyrotron over the conventional gyrotron is its continuous frequency tunability. Various techniques to tune the output frequency have been tested, such as changing the mirror separation, the beam voltage, or the main magnetic field. Within the limitations of the present setup, 5% tunability was achieved. The QO gyrotron designed for operation at the fundamental frequency exhibits simultaneous emission at 100 GHz (fundamental) and 200 GHz (second harmonic). For a beam current of 4 A, 20% of the total rf power is emitted at the second harmonic

  10. Quasi-optical gyrotron: present status and future prospect

    International Nuclear Information System (INIS)

    Tran, M.Q.

    1989-01-01

    A review of the main experiments on quasi-optical gyrotron is presented. Methods to improve the efficiency (pencil beam electron gun and depressed collector) will be discussed. (author) 5 figs., 1 tab., 10 refs

  11. Towards a 1 MW, 170 GHz gyrotron design for fusion application

    Science.gov (United States)

    Kumar, Anil; Kumar, Nitin; Singh, Udaybir; Bhattacharya, Ranajoy; Yadav, Vivek; Sinha, A. K.

    2013-03-01

    The electrical design of different components of 1 MW, 170 GHz gyrotron such as, magnetron injection gun, cylindrical interaction cavity and collector and RF window is presented in this article. Recently, a new project related to the development of 170 GHz, 1 MW gyrotron has been started for the Indian Tokamak. TE34,10 mode is selected as the operating mode after studied the problem of mode competition. The triode type geometry is selected for the design of magnetron injection gun (MIG) to achieve the required beam parameters. The maximum transverse velocity spread of 3.28% at the velocity ratio of 1.34 is obtained in simulations for a 40 A, 80 kV electron beam. The RF output power of more than 1 MW with 36.5% interaction efficiency without depressed collector is predicted by simulation in single-mode operation at 170 GHz frequency. The simulated single-stage depressed collector of the gyrotron predicted the overall device efficiencies >55%. Due to the very good thermal conductivity and very weak dependency of the dielectric parameters on temperature, PACVD diamond is selected for window design for the transmission of RF power. The in-house developed code MIGSYN and GCOMS are used for initial geometry design of MIG and mode selection respectively. Commercially available simulation tools MAGIC and ANSYS are used for beam-wave interaction and mechanical analysis respectively.

  12. Diamond window and its application to ITER gyrotron

    International Nuclear Information System (INIS)

    Sakamoto, K.

    1999-01-01

    On the background of having to reduce the overall cost for ITER to 50% it is proposed to replace conventional glass windows on gyrotrons by diamonds. The successful production and testing of such diamond windows is reported. A diamond window can transmit 5 times more power than usual double disk transmission windows while only costing 3 times as much. As a tradeoff, the gyrotrons could be replaced by more powerful ones and one would need fewer of them

  13. High voltage K/sub a/-band gyrotron oscillator experiment

    International Nuclear Information System (INIS)

    Gold, S.H.; Fliflet, A.W.; Manheimer, W.M.; Black, W.M.; Granatstein, V.L.; Kinkead, A.K.; Hardesty, D.L.; Sucy, M.

    1986-01-01

    Future applications of millimeter-waves may require significantly higher powers (>100 MW) than are available from the long-pulse thermionic gyrotrons that are presently available or under development. Scaling studies suggest that these power levels should be accessible to gyrotrons employing relativistic (0.5-1 MeV), multi-kA electron beams, such as can be generated for short pulse lengths (≤100 nsec) using pulseline accelerators with plasma-induced field-emission cathodes. To explore this potential, the authors have assembled a new gyrotron experiment based on a compact Febetron pulser. Initial experiments using a 350keV, 700A electron beam with a ratio of transverse to longitudinal velocity of ≅0.75 have produced ≅20MW at 35GHz at 8.5% efficiency in a TE/sub 62/ mode, in good agreement with the predictions of theory for the experimental parameters. Substantially higher powers and efficiencies are predicted for a new experimental configuration, which will operate at a higher voltage with improved beam parameters. In this new experiment, a 600 keV, multi-kA electron beam will be produced with low initial transverse energy. Transverse kinetic energy will then be added to the beam either by resonant pumping, via a magnetic wiggler, or by transit through a nonadiabatic magnetic ''bump.'' Finally, the beam will be adiabatically compressed to the desired radius in the gyrotron cavity with a final α≅1. The authors plan to report on the latest results from this new experimental configuration

  14. Operations Studies of the Gyrotrons on DIII-D

    Science.gov (United States)

    Storment, Stephen; Lohr, John; Cengher, Mirela; Gorelov, Yuri; Ponce, Dan; Torrezan, Antonio

    2017-10-01

    The gyrotrons are high power vacuum tubes used in fusion research to provide high power density heating and current drive in precisely localized areas of the plasma. Despite the increasing experience with both the manufacture and operation of these devices, individual gyrotrons with similar design and manufacturing processes can exhibit important operational differences in terms of generated rf power, efficiency and lifetime. This report discusses differences in the performance of several gyrotrons in operation at DIII-D and presents the results of a series of measurements that could lead to improved the performance of single units based on a better understanding of the causes of these differences. The rf power generation efficiency can be different from gyrotron to gyrotron. In addition, the power loading of the collector can feature localized hot spots, where the collector can locally be close to the power deposition limits. Measurements of collector power loading provide maps of the power deposition and can provide understanding of the effect of modulation of the output rf beam on the total loading, leading to improved operational rules increasing the safety margins for the gyrotrons under different operational scenarios. Work supported by US DOE under DE-FC02-04ER54698.

  15. Initial operation of a high-power quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Fliflet, A.W.; Hargreaves, T.A.; Manheimer, W.M.; Fischer, R.P.; Barsanti, M.L.

    1990-01-01

    Results from the initial operating of a high-power quasi-optical gyrotron based on the 90-kV 50-A Varian VUW-8144 electron gun are reported. The output power and efficiency have been measured for a resonator mirror separation of 19.4 cm with a magnetic field of 4.95 T, corresponding to resonator output coupling of 1.9%, and for a resonator mirror separation of 21.4 cm with a magnetic field of 4.7 T, corresponding to a resonator output coupling of 3.1%. Operation was multimoded with 3--6 modes excited in the range of 125--130 GHz for the 4.95-T magnetic field. A peak efficiency of 15% at an output power of 161 kW was obtained for a gun voltage of 93 kV and a current of 12 A. A peak-output power of 364 kW at an efficiency of 10% was obtained at a voltage of 95.6 kV and 37.5 A

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

    Science.gov (United States)

    Polevoy, Jeffrey Todd

    1989-06-01

    Experimental measurements of the average axial velocity v(sub parallel) 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 V(sub p) and the beam current I(sub b). The V(sub p) is measured through the use of a capacitive probe installed near or within the gyrotron cavity, while I(sub b) 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 v(sub parallel) and calculations of the corresponding transverse to longitudinal beam velocity ratio (alpha) = v(sub perpendicular)/v(sub parallel) 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 v(sub parallel) and (alpha) are determined through the use of a computer code (EGUN) which is used to model the cathode and anode regions of the gyrotron. It also computes the trajectories and velocities of the electrons within the gyrotron. There is good correlation between the expected and measured values of (alpha) at low (alpha), with the expected values from EGUN often falling within the standard errors of the measured values.

  17. Stability and nonlinear dynamics of gyrotrons at cyclotron harmonics

    International Nuclear Information System (INIS)

    Saraph, G.P.; Nusinovich, G.S.; Antonsen, T.M. Jr.; Levush, B.

    1992-01-01

    Gyrotrons operating at higher harmonics of the cyclotron frequency can overcome the frequency limitations caused by achievable strength of the magnetic field. However, the excitation of modes at the fundamental frequency exhibit a major problem for stable operation of harmonic gyrotron at high power with high efficiency. Therefore the issues of stability of gyrotron operation at the cyclotron harmonics and nonlinear dynamics of mode interaction are of great importance. The results of the authors stability analysis and multimode simulation are presented here. A detailed nonlinear theory of steady state single mode operation at cyclotron harmonics has been presented previously, taking into account beam-wave coupling and nonlinear gain function at cyclotron harmonics. A set of equations describing low gain regime interaction of modes resonant at different cyclotron harmonics was studied before. The multifrequency time-dependent nonlinear analysis presented here is based on previous gyrotron studies and beam-wave interaction at cyclotron harmonics. The authors have determined the parameter space for stable single mode operation at the second harmonic. The nonlinear dynamics of mode evolution and mode interaction for a harmonic gyrotron is presented. A new nonlinear effect in which the parasite at the fundamental harmonic helps excite the operating mode at the second harmonic has been demonstrated

  18. Circuit design and simulation of a HV-supply controlling the power of 140 GHz 1 MW gyrotrons for ECRH on W7-X

    International Nuclear Information System (INIS)

    Brand, P.; Mueller, G.A.

    2003-01-01

    For plasma heating by ECR in the Stellarator W7-X under construction, 140 GHz gyrotrons with 1 MW cw output power are under development. These tubes have a voltage depressed collector for electron energy recovery. Each gyrotron is fed by two high-voltage sources: a high-power supply for driving the electron beam and a precision low-power supply for beam acceleration. In addition, a protection system with a thyratron crowbar for fast power removal in case of gyrotron arcing is installed. The low-power high-voltage source for beam acceleration is realized by a high-voltage servo-amplifier driving the depression voltage such that the influence of the voltage noise of the main high-power supply on the acceleration voltage is suppressed by feed-back control of the amplifier. Design and simulation of the servo-amplifier by PSpice is presented

  19. Cusp-Gun Sixth-Harmonic Slotted Gyrotron

    Science.gov (United States)

    Stutzman, R. C.; McDermott, D. B.; Hirata Luhmann, Y., Jr.; Gallagher, D. A.; Spencer, T. A.

    2000-10-01

    A high-harmonic slotted gyrotron has been constructed at UC Davis to be driven by a 70 kV, 3.5 A, axis-encircling electron beam from a Northrop Grumman Cusp gun. The 94 GHz, slotted sixth-harmonic gyrotron is predicted to generate 50 kW with an efficiency of 20%. Using the profile of the adiabatic field reversal from the UC Davis superconducting test-magnet, EGUN simulations predict that an axis-encircling electron beam will be generated with an axial velocity spread of Δ v_z/v_z=10% for the desired velocity ratio of α =v_z/v_z=1.5. The design will also be presented for an 8th-harmonic W-band gyrotron whose magnetic field can be supplied by a lightweight permanent magnet.

  20. Thermal analysis of gyrotron traveling-wave tube collector

    International Nuclear Information System (INIS)

    Zheng Zhiqing; Luo Yong; Jiang Wei; Tang Yong

    2013-01-01

    In order to solve cooling problem of the gyrotron traveling-wave tube(TWT) collector and guarantee the gyrotron TWT's reliability and stability, the electron trajectories in the gyrotron TWT are simulated using CST electron simulation software. Thermal analysis of the collector with finite element software ANSYS is performed. The ways of applying boundary that affects the distribution of collector temperature are compared. The influence of the water temperature and flow rate on collector temperature distribution under actual heat fluxes (boundary condition) is researched. The size and number of collector fins are optimized, and a relatively perfect structure is obtained finally. The result estimated by simulation is consistent with the experiment and proves that the model and method employed in this work are suitable. (authors)

  1. Kocuria varians infection associated with brain abscess: A case report

    Directory of Open Access Journals (Sweden)

    Tsai Tai-Hsin

    2010-04-01

    Full Text Available Abstract Background Kocuria, established by Stackebrandt et al., previously was classified into Micrococcus. Only two species, K. rosea and K. kristinae are reported to be associated as pathogenic and found with catheter-related bacteremia and acute cholecystitis. Case presentation We herein report the first case of brain abscess caused by Kocuria varians, a gram-positive microorganism, in a 52-year-old man. Hematogenous spread is the probable pathogenesis. Conclusions This report presents a case of Kocuria varians brain abscess successfully treated with surgical excision combined with antimicrobial therapy. In addition, Vitek 2 system has been used to identify and differentiate between coagulase-negative staphylococcus.

  2. Kocuria varians infection associated with brain abscess: a case report.

    Science.gov (United States)

    Tsai, Cheng-Yu; Su, Shou-hsin; Cheng, Yu-Hsin; Chou, Yu-lin; Tsai, Tai-Hsin; Lieu, Ann-Shung

    2010-04-27

    Kocuria, established by Stackebrandt et al., previously was classified into Micrococcus. Only two species, K. rosea and K. kristinae are reported to be associated as pathogenic and found with catheter-related bacteremia and acute cholecystitis. We herein report the first case of brain abscess caused by Kocuria varians, a gram-positive microorganism, in a 52-year-old man. Hematogenous spread is the probable pathogenesis. This report presents a case of Kocuria varians brain abscess successfully treated with surgical excision combined with antimicrobial therapy. In addition, Vitek 2 system has been used to identify and differentiate between coagulase-negative staphylococcus.

  3. The Varian MAT-250 mass spectrometer. Steady isotopes laboratory

    International Nuclear Information System (INIS)

    Hernandez M, V.; Tavera D, M.L.

    1997-01-01

    This work treats over the performance and applications of the Varian Mat-250 mass spectrometer which is in the environmental isotope laboratory. It can be applied over topics such as: ions formation, acceleration and collimation, ions separation, ions detection, data transformation, sampling, δ notation. (Author)

  4. Design of 28 GHz, 200 kW Gyrotron for ECRH Applications

    Science.gov (United States)

    Yadav, Vivek; Singh, Udaybir; Kumar, Nitin; Kumar, Anil; Deorani, S. C.; Sinha, A. K.

    2013-01-01

    This paper presents the design of 28 GHz, 200 kW gyrotron for Indian TOKAMAK system. The paper reports the designs of interaction cavity, magnetron injection gun and RF window. EGUN code is used for the optimization of electron gun parameters. TE03 mode is selected as the operating mode by using the in-house developed code GCOMS. The simulation and optimization of the cavity parameters are carried out by using the Particle-in-cell, three dimensional (3-D)-electromagnetic simulation code MAGIC. The output power more than 250 kW is achieved.

  5. Advances in High Power Calorimetric Matched Loads for Short Pulses and CW Gyrotrons

    International Nuclear Information System (INIS)

    Bin, W.M.; Bruschi, A.; Cirant, S.; Gandini, F.; Granucci, G.; Mellera, V.; Muzzini, V.; Nardone, A.; Sozzi, C.; Spinicchia, N.

    2006-01-01

    The development of high power gyrotrons for plasma physics research needs proper matched and calorimetric loads able to absorb and measure the power, which nowadays is foreseen to be as high as 2 MW during CW operations. To this end IFP/CNR has developed a family of matched loads useful in the mm-wave frequency band for applications ranging from a few ms to CW in pulse length. The different loads in the family, made of an integrating sphere with a partially reflecting coating on the inner wall, are characterized by having the same absorbing geometry for the incoming beam and a different heat removal system for the specific application. Some important advances have been recently achieved from the point of view of the uniformity of power distribution on the absorbing wall and of the load construction. With high precision achieved in the coating thickness a better control of the heating power distribution is possible by proper shaping of the local reflectivity, in addition to the shaping of the mirror dispersing the input beam. A more sophisticated model describing the power distribution has been developed, taking into account a variable thickness of the absorbing coating, the proper shape of the spreading mirror, the frequency of the incoming radiation and the shape of the input beam. Lower coating thickness is shown to be preferable, at equal local reflectivity, from the point of view of a lower peak temperature and thermal stress. The paper describes a load with variable coating thickness along the meridian of the sphere, showing a uniform power deposition on the inner walls. The cooling pipe is completely electroformed on the spherical copper shell, ensuring the maintenance of the correct curvature of the inner surface and a fast heat conduction from the absorbing coating to the water through the thin copper body. For CW use all heated parts of the load must be cooled and this is achieved by 16 electroformed spiral channels. Both short pulse loads (0.1-1 s) and

  6. Design of the all solid high-voltage power supply for a gyrotron body

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Yihua [School of Mathematics and Physics, University of South China, Hengyang, 421001 (China); Chen, Wenguang, E-mail: 430000485393@usc.edu.cn [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Hu, Bo [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Rao, Jun; Huang, Mei; Kang, Zihua; Feng, Kun [Southwestern Institute of Physics, Chengdu, 610041 (China); Huang, Jiaqi [School of Electrical Engineering, University of South China, Hengyang, 421001 (China)

    2017-04-15

    Highlights: • Completed design of all solid-state high-voltage power supply for gyrotron body on HL-2M ECRH. • Consist of 58 PSM modules and one BUCK module, controlled by DSP system. • Fabricated full voltage 35 kV, 200 mA BPS and tested in dummy load. • The BPS can operate in three modes: single pulse mode, multi-pulse modulation mode and the six-level preset mode. - Abstract: Gyrotron plays an important role in the research of electron cyclotron resonance heating (ECRH) on Tokomak. The high-frequency switched power supply technology and pulse step modulation (PSM) technology are used in the development of the all solid high-voltage body power supply (BPS) for 1 MW/105 GHz Gyrotron on ECRH system. Firstly, the basic structure of the BPS and its control system are introduced. Secondly, the software control algorithm of voltage stabilization and modulate method are developed. Finally, the design is verified by the experiments. The experimental results of the single pulse mode, the multi-pulse modulation mode and the six-level preset mode, are shown. The output voltage of the power supply can reach 35 kV and the current at about 200 mA, which are adjustable in the full range. The maximum modulation frequency can reach 1 kHz and the front edge of the pulse can be adjust from 0 to 3 ms and the accuracy of the output voltage is less than 100 V. The results show that the control method is feasible and can be applied to other high power microwave sources.

  7. The Varian MAT-250 mass spectrometer. Steady isotopes laboratory; Espectrometro de masas Varian MAT-250. Laboratorio de isotopos estables

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, V.; Tavera D, M.L. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    This work treats over the performance and applications of the Varian Mat-250 mass spectrometer which is in the environmental isotope laboratory. It can be applied over topics such as: ions formation, acceleration and collimation, ions separation, ions detection, data transformation, sampling, {delta} notation. (Author)

  8. Experimental investigation of plasma-neutralized operation of a gyrotron

    International Nuclear Information System (INIS)

    Kirkpatrick, D.A.; Sullivan, C.; Gold, S.H.; Manheimer, W.M.; Levush, B.; Antonsen, T.M.

    1989-01-01

    The authors present plans and preliminary results of an experiment to investigate the effects of a neutralizing background plasma on the operation of a gyrotron oscillator. Previous experiments operating without a neutralizing background plasma achieved output powers P = 100 - 250MW at a frequency f = 35 GHz, with beam voltages in the range V = 0.60 - 1.35MV, and beam currents I = 1 -3kA. A completely ionized plasma is injected into a gyrotron interaction region from an upstream array of plasma guns. The peak plasma density available from the plasma guns exceeds n p > 10 13 cm -3 . The plasma density is measured by 70 GHz microwave interferometry and Langmuir probes. A high current electron beam from a field emission electron gun enters the plasma-filled gyrotron cavity from the upstream side. The density of the neutralizing plasma is varied by changing the delay between the firing of plasma guns and the VEBA accelerator. The authors present measurements of the transmitted electron beam current. Subsequent design of a gyrotron oscillator which utilizes the enhanced capabilities are presented

  9. High-power and long-pulse operation of TE{sub 31,11} mode gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Ryosuke, E-mail: ikeda.ryosuke@jaea.go.jp; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Sakamoto, Keishi

    2015-10-15

    Highlights: • We are under development of TE{sub 31,11} mode gyrotron to aim ITER specification. • HE{sub 11} mode purity reached 96% of ITER specification. • Mode competition was suppressed in initial phase of oscillation by anode voltage control. • Maximum output power of 1.2 MW was achieved. • Steady state operation of 500 MJ was achieved. - Abstract: The ITER electron cyclotron system is designed to inject a 20 MW RF beam by using twenty-four 170 GHz/1 MW gyrotrons. JAEA is currently developing a gyrotron having a high-order mode (TE{sub 31,11}) to reduce the heat load in the cavity resonator and achieve an output power greater than 1 MW. The measured radiation profile at the front of the diamond window agreed with the results of the calculation. In order to suppress RF loss in the equatorial and upper port launchers, a high-quality HE{sub 11} mode is required at the exit of the matching optics unit (MOU). An HE{sub 11} mode purity of 96% was achieved by finely adjusting the two mirrors in the MOU. During the oscillation start-up phase, mode competition with counter-rotating TE{sub 29,12} mode was observed on the higher magnetic field side which caused arcing and pressure increase in the gyrotron. To avoid the counter-rotating TE{sub 29,12} mode from being excited, a start-up scenario that controls the voltage between the anode and cathode electrodes at the initial phase of operation was introduced, which was able to achieve a stable start-up of TE{sub 31,11} mode. A 1.2 MW output power having a total electric efficiency of 43% was obtained in high-power experiments. In steady-state operation, a 1000 s oscillation length and output power of 0.51 MW was achieved.

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

    International Nuclear Information System (INIS)

    Maebara, Sunao; Kasugai, Atsushi; Sakamoto, Keishi; Tsuneoka, Masaki; Imai, Tsuyoshi

    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)

  11. Stability analysis of a coaxial-waveguide gyrotron traveling-wave amplifier

    International Nuclear Information System (INIS)

    Hung, C.L.; Yeh, Y.S.

    2005-01-01

    The gyrotron traveling-wave tube (gyro-TWT) amplifier is known to be highly susceptible to spurious oscillations. This study develops a simulation approach to analyze the stability of a coaxial-waveguide gyro-TWT with distributed wall losses. The interplay among the absolute instabilities, the gyrotron backward-wave oscillations, and the circuit parameters is analyzed. Simulation results reveal that the distributed wall losses effectively stabilize spurious oscillations in the coaxial gyro-TWT. Furthermore, the wall resistivity of the center conductor is shown to be an additional effective mechanism for suppressing oscillations. Under stable operation conditions, the coaxial gyro-TWT with distributed losses is predicted to generate 435 kW in the Ka band with 31% efficiency, a saturated gain of 45 dB, and a bandwidth of 1.86 GHz (≅5.8%) for a 70 kV, 20 A electron beam with an α(=ν perpendicular )/ν z )=1.0 and an axial velocity spread of Δν z /ν z =5%

  12. Startup methods for single-mode gyrotron operation

    International Nuclear Information System (INIS)

    Whaley, D.R.; Tran, M.Q.; Alberti, S.; Tran, T.M.; Antonsen, T.M. Jr.; Dubrovin, A.; Tran, C.

    1995-01-01

    Experimental results of startup studies on a 118 GHz TE 22,6 gyrotron are presented and compared with theory. The startup paths through the energy-velocity-pitch-angle plane are determined by the time evolution of the beam parameters during the startup phase. These startup paths are modified by changing the anode and cathode voltage rise from zero to their nominal values and are seen to determine the cavity oscillating mode. Experimental results show specifically that competition between the TE 22,6 and TE -19,7 mode can be completely eliminated by use of the proper startup method in a case where a typical triode startup results in oscillation in the competing TE -19,7 mode. These new results are shown to be in excellent agreement with the theory whose approach is general and therefore applicable to gyrotrons operating in any arbitrary cavity mode. (author) 3 figs., 4 refs

  13. High-harmonic relativistic gyrotron as an alternative to FEL

    Energy Technology Data Exchange (ETDEWEB)

    Bratman, V L; Kalynov, Yu K; Kolganov, N G; Manuilov, V N; Ofitserov, M M; Samsonov, S V; Volkov, A B [Russian Academy of Sciences, Nizhny Novgorod (Russian Federation). Inst. of Applid Physics

    1997-12-31

    A submillimeter wave gyrotron operating at moderately relativistic electron energies of 200-300 keV is proposed as a simple alternative to FEL. It is shown that high pulsed magnetic fields of 20-30 T and selective excitation of separate modes for resonances up to the 5-7 th harmonics will make it possible to obtain in a single device the coherent radiation with broadband frequency step tuning within the whole submillimeter wavelength range. At large pitch angles the coupling of the electron beam with cavity modes at higher harmonics should be as strong as at the fundamental one. In order to check the theoretical predictions, two gyrotrons were designed: LOG-1 (250 kV, 10 A, 10 ms) with a thermionic emission cathode and LOG-2 (350 kV, 35 A, 20 ns) with an explosive emission cathode. (J.U.). 7 refs.

  14. Startup and mode competition in a 420 GHz gyrotron

    Science.gov (United States)

    Qixiang Zhao, A.; Sheng Yu, B.; Tianzhong Zhang, C.

    2017-09-01

    In the experiments of a 420 GHz second-harmonic gyrotron, it is found that the electron beam voltage and current ranges for single mode operation of TE17.4 are slightly narrower than those in the simulation. To explain this phenomenon, the startup scenario has been investigated with special emphasis on mode competition. The calculations indicate that the decreases of the operating ranges are caused by the voltage overshoot in the startup scenario.

  15. Photonic-band-gap gyrotron amplifier with picosecond pulses

    Science.gov (United States)

    Nanni, Emilio A.; Jawla, Sudheer; Lewis, Samantha M.; Shapiro, Michael A.; Temkin, Richard J.

    2017-12-01

    We report the amplification of 250 GHz pulses as short as 260 ps without observation of pulse broadening using a photonic-band-gap circuit gyrotron traveling-wave-amplifier. The gyrotron amplifier operates with a device gain of 38 dB and an instantaneous bandwidth of 8 GHz. The operational bandwidth of the amplifier can be tuned over 16 GHz by adjusting the operating voltage of the electron beam and the magnetic field. The amplifier uses a 30 cm long photonic-band-gap interaction circuit to confine the desired TE03-like operating mode while suppressing lower order modes which can result in undesired oscillations. The circuit gain is >55 dB for a beam voltage of 23 kV and a current of 700 mA. These results demonstrate the wide bandwidths and a high gain achievable with gyrotron amplifiers. The amplification of picosecond pulses of variable lengths, 260-800 ps, shows good agreement with the theory using the coupled dispersion relation and the gain-spectrum of the amplifier as measured with quasi-CW input pulses.

  16. A study of parametric instability in a harmonic gyrotron: Designs of third harmonic gyrotrons at 94 GHz and 210 GHz

    International Nuclear Information System (INIS)

    Saraph, G.P.; Antonsen, T.M. Jr.; Nusinovich, G.S.; Levush, B.

    1995-01-01

    Mode competition can present a major hurdle in achieving stable, efficient operation of a gyrotron at the cyclotron harmonics. A type of mode interaction in which three modes at different cyclotron harmonics are parametrically coupled together is analyzed here. This coupling can lead to parametric excitation or suppression of a mode; cyclic mode hopping; or the coexistence of three modes. Simulation results are presented for the parametric instability involving modes at the fundamental, second harmonic, and third harmonic of the cyclotron frequency. It is shown that the parametric excitation can lead to stable, efficient operation of a high-power gyrotron at the third harmonic. Based on this phenomenon, two practical designs are presented here for the third harmonic operation at 94 and 210 GHz. copyright 1995 American Institute of Physics

  17. Halophilic Nuclease from a Moderately Halophilic Micrococcus varians

    Science.gov (United States)

    Kamekura, Masahiro; Onishi, Hiroshi

    1974-01-01

    The moderately halophilic bacterium Micrococcus varians, isolated from soy sauce mash, produced extracellular nuclease when cultivated aerobically in media containing 1 to 4 M NaCl or KCl. The enzyme, purified to an electrophoretically homogeneous state, had both ribonuclease and deoxyribonuclease activities. The nuclease had maximal activity in the presence of 2.9 M NaCl or 2.1 M KCl at 40 C. The enzymatic activity was lost by dialysis against low-salt buffer, whereas when the inactivated enzyme was dialyzed against 3.4 M NaCl buffer as much as 77% of the initial activity could be restored. Images PMID:4852218

  18. Megawatt Power Level 120 GHz Gyrotrons for ITER Start-Up

    Energy Technology Data Exchange (ETDEWEB)

    Choi, E M; Marchewka, C; Mastovsky, I; Shapiro, M A; Sirigiri, J R; Temkin, R J [MIT - Plasma Science and Fusion Center, NW16-186, 167 Albany Street, Cambridge, MA 02139 (United States)

    2005-01-01

    We report operation of a 110 GHz gyrotron with 1.67 MW of output power measured in short pulses (3{mu}s) at an efficiency of 42% in the TE{sub 22,6} mode. We also present a preliminary design of a 1 MW, 120 GHz gyrotron for ITER start-up with an efficiency greater than 50%.

  19. Megawatt Power Level 120 GHz Gyrotrons for ITER Start-Up

    International Nuclear Information System (INIS)

    Choi, E M; Marchewka, C; Mastovsky, I; Shapiro, M A; Sirigiri, J R; Temkin, R J

    2005-01-01

    We report operation of a 110 GHz gyrotron with 1.67 MW of output power measured in short pulses (3μs) at an efficiency of 42% in the TE 22,6 mode. We also present a preliminary design of a 1 MW, 120 GHz gyrotron for ITER start-up with an efficiency greater than 50%

  20. 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.

  1. Mechanical reliability of current alumina and beryllia ceramics used in microwave windows for gyrotrons

    International Nuclear Information System (INIS)

    Becher, P.F.; Ferber, M.K.

    1983-02-01

    The mechanical reliability was evaluated for the alumina and beryllia ceramics now used as microwave windows in the high-power (greater than or equal to 200 kW) high-frequency (greater than or equal to 60 GHz) gyrotron tubes being developed for plasma heating in fusion systems. Analysis of the stresses generated in the various window configurations and tube operating conditions indicated that significant tensile stresses are generated in the ceramic window by dielectric heating. As a result, we characterized the static and dynamic fatigue behavior and the inert strength distributions for these two ceramics (i.e., fatigue studies included the behavior in the fluorocarbon fluid used for window cooling at 22 and 48 0 C and in both air (65% relative humidity) and distilled water at 22 0 C. These data were then analyzed in order to construct reliability diagrams for these materials

  2. Improved Design of Beam Tunnel for 42 GHz Gyrotron

    Science.gov (United States)

    Singh, Udaybir; Kumar, Nitin; Purohit, L. P.; Sinha, A. K.

    2011-04-01

    In gyrotron, there is the chance of generation and excitation of unwanted RF modes (parasite oscillations). These modes may interact with electron beam and consequently degrade the beam quality. This paper presents the improved design of the beam tunnel to reduce the parasite oscillations and the effect of beam tunnel geometry on the electron beam parameters. The design optimization of the beam tunnel has been done with the help of 3-D simulation software CST-Microwave Studio and the effect of beam tunnel geometry on the electron beam parameters has been analyzed by EGUN code.

  3. Nonlinearly driven oscillations in the gyrotron traveling-wave amplifier

    International Nuclear Information System (INIS)

    Chiu, C. C.; Pao, K. F.; Yan, Y. C.; Chu, K. R.; Barnett, L. R.; Luhmann, N. C. Jr.

    2008-01-01

    By delivering unprecedented power and gain, the gyrotron traveling-wave amplifier (gyro-TWT) offers great promise for advanced millimeter wave radars. However, the underlying physics of this complex nonlinear system is yet to be fully elucidated. Here, we report a new phenomenon in the form of nonlinearly driven oscillations. A zero-drive stable gyro-TWT is shown to be susceptible to a considerably reduced dynamic range at the band edge, followed by a sudden transition into driven oscillations and then a hysteresis effect. An analysis of this unexpected behavior and its physical interpretation are presented.

  4. Transmission Line for 258 GHz Gyrotron DNP Spectrometry

    Science.gov (United States)

    Bogdashov, Alexandr A.; Belousov, Vladimir I.; Chirkov, Alexey V.; Denisov, Gregory G.; Korchagin, Vyacheslav V.; Kornishin, Sergey Yu.; Tai, Evgeny M.

    2011-06-01

    We describe the design and test results of the transmission line for liquid-state (LS) and solid-state (SS) DNP spectrometers with the second-harmonic 258.6 GHz gyrotron at the Institute of the Biophysical Chemistry Center of Goethe University (Frankfurt). The 13-meter line includes a mode converter, HE11 waveguides, 4 mitre bends, a variable polarizer-attenuator, directional couplers, a water-flow calorimeter and a mechanical switch. A microwave power of about 15 W was obtained in the pure HE11 mode at the spectrometer inputs.

  5. Design of test JIG for centralized interlock and protection module of ITER-India Gyrotron Test Facility

    International Nuclear Information System (INIS)

    Rathod, Vipal; Rao, S.L.; Edappala, Praveenlal; Rajpal, Rachana

    2017-01-01

    Fast Interlock and protection system plays very crucial role in ensuring the safe and reliable operation of high power RF sources such as a Gyrotron system. Critical Protection Interlocks are generally implemented using hardwired components and are required to have a response time as fast as < 10 μs. In this context, an Industrial grade prototype Centralized Interlock and Protection Module (CIM) based on ITER-India design has been developed successfully with the help of local industry. This paper presents the complete requirements, approach, detailed design concept and current status of Test JIG in detail

  6. Startup methods for single-mode gyrotron operation

    International Nuclear Information System (INIS)

    Whaley, D.R.; Tran, M.Q.; Alberti, S.; Tran, T.M.; Antonsen, T.M.; Tran, C.

    1995-03-01

    Experimental results of startup studies on a 118 GHz TE 22,6 gyrotron are presented and compared with theory. The theoretical excitation regimes of competing modes are computed in the energy-velocity-pitch-angle plane near the operation point. The startup paths through the plane are determined by the time evolution of the beam parameters during the startup phase. These startup paths are modified by changing the anode and cathode voltage rise from zero to their nominal values and are seen to determine the cavity oscillating mode. Experimental results show specifically that competition between the TE 22,6 and TE -19,7 mode can be completely eliminated by using the proper startup method in a case where a typical triode startup results in oscillation in the competing TE -19,7 mode. These new results are shown to be in excellent agreement with theory whose approach is general and therefore applicable to gyrotrons operating in any arbitrary cavity mode. (author) 5 figs., 1 tab., 13 refs

  7. Quasi-optical mode converter for a coaxial cavity gyrotron

    International Nuclear Information System (INIS)

    Jin, J.

    2007-03-01

    This work concentrates on the synthesis of the quasioptical mode converter for the 170 GHz, TE 34,19 -mode, 2MW, CW coaxial-cavity gyrotron at Forschungszentrum Karlsruhe (FZK). The improvement of the general method for the design of so-call dimpled-wall launcher to provide a good Gaussian mode content is described. This method is verified through the design of a launcher operating in the TE 22,6 mode at 118 GHz. A phase rule is proposed as a quality criterion for monitoring the optimization and the choices of parameters of the quasi-optical mode converter. High-order harmonics introduced to the launcher wall deformations are proposed for this gyrotron. The launcher is numerically optimized, the fields on the cut edges are suppressed. The fields in the launcher are well approximated by the waveguide modes, the radiated fields are calculated using the scalar diffraction integral. The procedure for the numerical optimization of the mirror system is improved, the tolerance conditions of the phase correcting mirrors are investigated. A conversion efficiency of 95.8% to the circular fundamental Gaussian distribution with 20mm beam waist and power transmission of 90% are achieved in the window plane using the optimized quasi-optical mode converter. The methods to ameliorate the initial conditions of the phase correcting mirrors are explored. (orig.)

  8. Modelling, simulation and computer-aided design (CAD) of gyrotrons for novel applications in the high-power terahertz science and technologies

    Science.gov (United States)

    Sabchevski, S.; Idehara, T.; Damyanova, M.; Zhelyazkov, I.; Balabanova, E.; Vasileva, E.

    2018-03-01

    Gyrotrons are the most powerful sources of CW coherent radiation in the sub-THz and THz frequency bands. In recent years, they have demonstrated a remarkable potential for bridging the so-called THz-gap in the electromagnetic spectrum and opened the road to many novel applications of the terahertz waves. Among them are various advanced spectroscopic techniques (e.g., ESR and DNP-NMR), plasma physics and fusion research, materials processing and characterization, imaging and inspection, new medical technologies and biological studies. In this paper, we review briefly the current status of the research in this broad field and present our problem-oriented software packages developed recently for numerical analysis, computer-aided design (CAD) and optimization of gyrotrons.

  9. Performance, diagnostics, controls and plans for the gyrotron system on the DIII-D tokamak

    Directory of Open Access Journals (Sweden)

    Ponce D.M.

    2012-09-01

    Full Text Available The DIII-D ECH complex is being upgraded with three new depressed collector gyrotrons. The performance of the existing system has been very good. As more gyrotrons having higher power are added to the system, diagnostics of gyrotron operation, optimization of the performance and qualification of components for higher power become more important. A new FPGA-based gyrotron control system is being installed, additional capabilities for rapid real time variation of the rf injection angles by the DIII-D Plasma Control System are being tested and infrastructure enhancements are being completed. Longer term plans continue to include ECH as a major component in the DIII-D heating and current drive capabilities.

  10. High Power Microwave Emission of Large and Small Orbit Gyrotron Devices in Rectangular Interaction Structures

    Science.gov (United States)

    Hochman, J. M.; Gilgenbach, R. M.; Jaynes, R. L.; Rintamaki, J. I.; Luginsland, J. W.; Lau, Y. Y.; Spencer, T. A.

    1996-11-01

    Experiments utilize large and small orbit e-beam gyrotron devices in a rectangular-cross-section (RCS) gyrotron. This device is being explored to examine polarization control. Other research issues include pulse shortening, and mode competition. MELBA generates electron beams with parameters of: -800kV, 1-10kA diode current, and 0.5-1.0 μ sec pulselengths. The small orbit gyrotron device is converted to a large orbit experiment by running MELBA's annular electron beam through a magnetic cusp. Initial experiments showed an increase in beam alpha (V_perp/V_par) of a factor of ~ 4 between small and large orbit devices. Experimental results from the RCS gyrotron will be compared for large-orbit and small-orbit electron beams. Beam transport data and frequency measurements will be presented. Computer modeling utilizing the MAGIC and E-gun codes will be shown.

  11. Validation of FORTRAN emulators for the G2 varian control programs

    International Nuclear Information System (INIS)

    Delorme, G.

    1996-01-01

    The extensive use of the Gentilly full scope simulator for training and verification of plant procedures, forced the development of a reliable desktop simulator for software maintenance purposes. For that we needed emulators for the control programs which run on the DCC Varian computers in the full scope simulator. This paper presents the validation results for the Reactor Regulating System (RRS) program. This emulator was programmed in a modular fashion providing ease of maintenance and of transportation to another environment. The results obtained with specific tests or with integrated testing involving complex control rule interactions, compared favorably with the ones obtained using the actual plant control programs running on the full scope simulator, which constitutes an irrefutable validation procedure. This RRS package along with the other emulators being validated In this manner could be used in safety codes with confidence. (author)

  12. The first preliminary experiments on an 84 GHz gyrotron with a single-stage depressed collector

    International Nuclear Information System (INIS)

    Shimozuma, T.; Sato, M.; Takita, Y.

    1997-10-01

    We fabricated and tested an 84GHz gyrotron with a single-stage depressed collector. The gyrotron has a high-voltage insulating section made of a low loss silicon nitride composite. In this preliminary experiment in the depressed collector configuration, we obtained 591kW, 41% operation with a depression voltage of 22.5kV. Access to the higher efficiency region was inhibited by an increase in anode current. (author)

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

    International Nuclear Information System (INIS)

    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

  14. Frequency pulling in a low-voltage medium-power gyrotron

    Science.gov (United States)

    Luo, Li; Du, Chao-Hai; Huang, Ming-Guang; Liu, Pu-Kun

    2018-04-01

    Many recent biomedical applications use medium-power frequency-tunable terahertz (THz) sources, such as sensitivity-enhanced nuclear magnetic resonance, THz imaging, and biomedical treatment. As a promising candidate, a low-voltage gyrotron can generate watt-level, continuous THz-wave radiation. In particular, the frequency-pulling effect in a gyrotron, namely, the effect of the electron beam parameters on the oscillation frequency, can be used to tune the operating frequency. Most previous investigations used complicated and time-consuming gyrotron nonlinear theory to study the influence of many beam parameters on the interaction performance. While gyrotron linear theory investigation demonstrates the advantages of rapidly and clearly revealing the physical influence of individual key beam parameters on the overall system performance, this paper demonstrates systematically the use of gyrotron linear theory to study the frequency-pulling effect in a low-voltage gyrotron with either a Gaussian or a sinusoidal axial-field profile. Furthermore, simulations of a gyrotron operating in the first axial mode are carried out in the framework of nonlinear theory as a contrast. Close agreement is achieved between the two theories. Besides, some interesting results are obtained. In a low-current sinusoidal-profile cavity, the ranges of frequency variation for different axial modes are isolated from each other, and the frequency tuning bandwidth for each axial mode increases by increasing either the beam voltage or pitch factor. Lowering the voltage, the total tuning ranges are squeezed and become concentrated. However, the isolated frequency regions of each axial mode cannot be linked up unless the beam current is increased, meaning that higher current operation is the key to achieving a wider and continuous tuning frequency range. The results presented in this paper can provide a reference for designing a broadband low-voltage gyrotron.

  15. 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)

    Castro, J.J.B. de.

    1988-12-01

    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 (η perpendicular MAX =0.86) have been calculated for interaction at the fundamental 1 cyclotron harmonic and for uniform external magnetic field. A maximum efficiency scaling parameter S has been introduced, by which scaling relations η perpendicular MAX = η perpendicular MAX (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 TE 021 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) [pt

  16. Analysis of parasitic oscillations in 42 GHz gyrotron beam tunnel

    Science.gov (United States)

    Kumar, N.; Singh, U.; Singh, T. P.; Sinha, A. K.

    2011-02-01

    Parasitic oscillation excitation analysis has been carried out for the 42 GHz gyrotron beam tunnel. This article presents a systematic approach for the analysis of parasitic oscillation excitation. The electron trajectory code EGUN has been used for the estimation of the electron beam parameters in the beam tunnel. The electromagnetic simulation code CST-MS has been used for the eigenmode and Q value analysis. The analysis of the parasitic oscillations has been performed for the symmetric TE modes and the first three cavity side copper rings. Four different approaches- the Q value study, the mode maxima-electron beam radius mismatching, the electron cyclotron frequency-mode excitation frequency mismatching and the backward wave interaction analysis- have been used for the parasitic oscillation analysis.

  17. Advantages of using gyrotron scattering for alpha particle diagnostics

    International Nuclear Information System (INIS)

    Woskoboinikow, P.P.; Cohn, D.R.; Machuzak, J.S.; Myer, R.C.; Rhee, R.Y.

    1987-07-01

    Millimeter-wave gyrotron collective Thomson scattering can be an effective diagnostic technique for the study of alpha particle behavior in ignited plasmas. The measurement of alpha particle density, velocity distribution, and alpha particle induced plasma instabilities can be accomplished with both spatial and temporal resolution. Advantages include long pulse operation which can make possible very high signal to noise ratios and use of millimeter waves which maximizes the Doppler shifted scattered signal in WHz -1 and makes possible scattering angles up to 180 0 . Extraordinary mode scattering at approximately 60 and 200 GHz would be used in TFTR and CIT respectively, and 140 GHz ordinary mode scattering in JET. 8 refs., 1 fig

  18. New design for the anode power supply of a gyrotron

    International Nuclear Information System (INIS)

    Fasel, D.; Alberti, S.; Favre, A.; Perez, A.; Acero, J.; Ganuza, D.; Garcia, I.; Lucia, C.

    1998-01-01

    The introduction will remind the main supply structure installed in the CRPP, related to the ECRH (Electron Cyclotron Resonance Heating) project on the TCV (Tokamak Configuration Variable) tokamak. Then this paper concentrates on the description of the power source designed to supply the anode of the triode type gyrotron. First the requirements asked for this power supply will be presented, taking into account the possible feeding structures in relation with the existing HV DC cathode power supply. The following section will focus on the selected design, describing in details the power structure based on MOSFET, referred to the cathode potential. Afterwards the control electronics is presented, including the feedback control implemented, the HV measurements, the internal reference generator and the interface to the TCV control. Finally, the last section will give information on the project status. (author)

  19. Operation and control of high power Gyrotrons for ECRH systems in SST-1 and Aditya

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, B.K., E-mail: shukla@ipr.res.in; Bora, D.; Jha, R.; Patel, Jatin; Patel, Harshida; Babu, Rajan; Dhorajiya, Pragnesh; Dalakoti, Shefali; Purohit, Dharmesh

    2016-11-15

    Highlights: • Operation and control of high power Gyrotrons. • Data acquisition and control (DAQ) for Gyrotron system. • Ignitron based crowbar protection. • VME and PXI based systems. - Abstract: The Electron Cyclotron Resonance Heating (ECRH) system is an important heating system for the reliable start-up of tokamak. The 42 GHz and 82.6 GHz ECRH systems are used in tokamaks SST-1 and Aditya to carry out ECRH related experiments. The Gyrotrons are high power microwave tubes used as a source for ECRH systems. The Gyrotron is a delicate microwave tube, which deliver megawatt level power at very high voltage ∼40–50 kV with the current requirement ∼10 A–50 A. The Gyrotrons are associated with the subsystems like: High voltage power supplies (Beam voltage and anode voltage), dedicated crowbar system, magnet, filament and ion pump power supplies, cooling, interlocks and a dedicated data acquisition & control (DAC) system. There are two levels of interlocks used for the protection of Gyrotron: fast interlocks (arcing, beam over current, dI/dt, anode voltage and anode over current etc.) operate within 10 μs and slow interlocks (cooling, filament, silence of Gyrotron, ion pump and magnet currents) operate within 100 ms. Two Gyrotrons (42 GHz/500 kW/500 ms and 82.6 GHz/200 kW/1000 s) have been commissioned on dummy load for full parameters. The 42 GHz ECRH system has been integrated with SST-1 & Aditya tokamak and various experiments have been carried out related to ECRH assisted breakdown and start-up of tokamak at fundamental and second harmonic. These Gyrotrons are operated with VME based data acquisition and control (DAC) system. The DAC system is capable to acquire 64 digital and 32 analog signals. The system is used to monitor & acquire the data and also used for slow interlocks for the protection of Gyrotron. The data acquired from the system are stored online on VME system and after the shot stored in a file in binary format. The MDSPlus, a set of

  20. Spirogyra varians mutant generated by high dose gamma-irradiation shows increased antioxidant properties

    International Nuclear Information System (INIS)

    Lee, Hak-Jyung; Yoon, Minchul; Sung, Nak-Yun; Choi, Jong-il

    2012-01-01

    The aim of this study was to evaluate the antioxidant properties of a Spirogyra varians mutant (Mut) produced by gamma irradiation. Methanol extracts were prepared from Spirogyra varians wild-type and Mut plants, and their antioxidant activities and total phenolic content (TPC) were determined. Antioxidant parameters, including the 2-diphenyl-1-picrylhydrazyl radical-scavenging activity and ferric-reducing/antioxidant power, were higher in the Mut extract. Moreover, the TPC level was higher (P<0.05) in the Mut methanol extract. Therefore, these results suggest that gamma irradiation-induced S. varians Mut has superior antioxidant properties. - Highlights: ► The antioxidative properties of a Spirogyra varians mutant produced by gamma-irradiation was investiated. ► The antioxidant activities and total phenolic content levels were higher in mutant strain. ► These results suggest that gamma-irradiation induced algae mutant with superior antioxidant properties.

  1. Morphological plasticity in the tropical sponge Anthosigmella varians: responses to predators and wave energy.

    Science.gov (United States)

    Hill, Malcolm S; Hill, April L

    2002-02-01

    The goal of the research presented here was to examine phenotypic plasticity exhibited by three morphotypes of the common Caribbean sponge Anthosigmella varians (Duchassaing & Michelotti). We were interested in examining the biotic (and, to a lesser extent, abiotic) factors responsible for branch production in this species. We also tested the hypothesis that the skeleton may serve an antipredator function in this sponge, focusing on vertebrate fish predators (i.e., angelfish) in this work. In transplant and caging experiments, unprotected forma varians replicates were immediately consumed by angelfish, while caged replicates persisted on the reef for several months. These findings support the hypothesis that predators (and not wave energy) restrict forma varians to lagoonal habitats. Branch production was not observed in A. varians forma incrustans when sponges were protected from predators or placed in predator-free, low-wave-energy environments. It is not clear from our work whether forma incrustans is capable of producing branches (i.e., whether branch production is a plastic trait in this morph). Additional field experiments demonstrated that A. varians forma varians increased spicule concentrations, compared to uninjured sponges, in response to artificial predation events, and A. varians forma rigida reduced spicule concentrations, compared to uncaged controls, when protected from predators. These findings indicate that spicule concentration is a plastic morphological trait that can be induced by damage, and that A. varians may be able to reduce spicule concentrations when environmental conditions change (e.g., in the absence of predators). The potential significance of inducible defenses and structural anti-predator defenses in sponges is discussed in relation to recent work on sponge chemical defenses.

  2. Plasma scattering measurement using a submillimeter wave gyrotron as a radiation source

    International Nuclear Information System (INIS)

    Ogawa, I.; Idehara, T.; Itakura, Y.; Myodo, M.; Hori, T.; Hatae, T.

    2004-01-01

    Plasma scattering measurement is an effective technique to observe low frequency density fluctuations excited in plasma. The spatial and wave number resolutions and the S/N ratio of measurement depend on the wavelength range, the size and the intensity of a probe beam. A well-collimated, submillimeter wave beam is suitable for improving the spatial and wave number resolutions. Application of high frequency gyrotron is effective in improving the S/N ratio of the measurement because of its capacity to deliver high power. Unlike the molecular vapor lasers, the gyrotrons generate diverging beam of radiation with TE mn mode structure. It is therefore necessary to convert the output radiation into a Gaussian beam. A quasi-optical antenna is a suitable element for the conversion system under consideration since it is applicable to several TE 0n and TE 1n modes. In order to apply the gyrotron to plasma scattering measurement, we have stabilized the output (P = 110 W, f = 354 GHz) of gyrotron up to the level (ΔP/P < 1 %, Δf< 10 kHz). The gyrotron output can be stabilized by decreasing the fluctuation of the cathode potential. (authors)

  3. Poster — Thur Eve — 55: An automated XML technique for isocentre verification on the Varian TrueBeam

    International Nuclear Information System (INIS)

    Asiev, Krum; Mullins, Joel; DeBlois, François; Liang, Liheng; Syme, Alasdair

    2014-01-01

    Isocentre verification tests, such as the Winston-Lutz (WL) test, have gained popularity in the recent years as techniques such as stereotactic radiosurgery/radiotherapy (SRS/SRT) treatments are more commonly performed on radiotherapy linacs. These highly conformal treatments require frequent monitoring of the geometrical accuracy of the isocentre to ensure proper radiation delivery. At our clinic, the WL test is performed by acquiring with the EPID a collection of 8 images of a WL phantom fixed on the couch for various couch/gantry angles. This set of images is later analyzed to determine the isocentre size. The current work addresses the acquisition process. A manual WL test acquisition performed by and experienced physicist takes in average 25 minutes and is prone to user manipulation errors. We have automated this acquisition on a Varian TrueBeam STx linac (Varian, Palo Alto, USA). The Varian developer mode allows the execution of custom-made XML script files to control all aspects of the linac operation. We have created an XML-WL script that cycles through each couch/gantry combinations taking an EPID image at each position. This automated acquisition is done in less than 4 minutes. The reproducibility of the method was verified by repeating the execution of the XML file 5 times. The analysis of the images showed variation of the isocenter size less than 0.1 mm along the X, Y and Z axes and compares favorably to a manual acquisition for which we typically observe variations up to 0.5 mm

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

    International Nuclear Information System (INIS)

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

    2006-01-01

    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

  5. Simulation of Non-Uniform Electron Beams in the Gyrotron Electron-Optical System

    Science.gov (United States)

    Louksha, O. I.; Trofimov, P. A.

    2018-04-01

    New calculated data on the effect of emission inhomogeneities on the quality of the electron beam, which is formed in an electron-optical system of a gyrotron, have been obtained. The calculations were based on emission current density distributions, which were measured for the different cathodes in the gyrotron of Peter the Great St. Petersburg Polytechnic University. A satisfactory agreement between the experimental and calculated data on the influence of emission nonuniformities on the velocity spread of electrons has been shown. The necessity of considering the real distribution of the emission current density over the cathode surface to determine the main parameters of the electron beam—the velocity and energy spreads of the electrons, spatial structure of the beam, and coefficient of reflection of electrons from the magnetic mirror—has been demonstrated. The maximum level of emission inhomogeneities, which are permissible for effective work of gyrotrons, has been discussed.

  6. 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.

  7. Cold test measurements on components of the 1 MW, 140 GHz, CW gyrotron for the stellarator Wendelstein 7-X

    International Nuclear Information System (INIS)

    Dammertz, G.; Alberti, S.; Arnold, A.; Giguet, E.; LeGoff, Y.; Thumm, M.

    2001-01-01

    For the development of a 1 MW, 140 GHz gyrotron for CW operation which will be installed at the stellarator facility Wendelstein 7-X at IPP Greifswald, a collaboration between different European research institutes and an industrial company has been established. In order to prove the proper functioning of the millimeter wave components installed in the gyrotron -- such as the cavity, the waveguide taper and the quasioptical mode converter -- these components should be cold tested, preferably before installation. However, due to lack of time as well as long delivery times, this was not possible. Therefore, two units of the quasioptical mode converter and the cavity were fabricated with identical geometry, one of those being used for measurements on the low power test device. To perform these cold tests for tapers and mode converters, the gyrotron cavity output mode has to be simulated. This means that a high order rotating mode (TE 28,8 mode) must be generated at low power. This can be achieved by means of a mode generator consisting of two mirrors and a coaxial cavity with a perforated outer wall. Before applying the mode generator to the components, its proper behavior and the accurate alignment of the system must be verified either by radiation pattern measurements or k-spectrometer measurements. As the coupling through the holes of the k-spectrometer is extremely low, a special vector network analyzer with a dynamic range of at least 100 dB had to be developed. This has been achieved by integration of a phase locked backward-wave oscillator with a line width of 100 Hz and an output power of 10 mW. A non-destructive measurement of the resonance frequency and the quality factor of the cavity does not seem possible. The second cavity will be prepared for the cold measurement by drilling a small radial hole into its wall in the plane of the field maximum. This hole is then used for the input coupling. The accuracy required for this hole is rather critical. The

  8. The three-dimensional particle-in-cell simulation analysis of cavity of high power subterahertz pulsed gyrotron

    International Nuclear Information System (INIS)

    Ito, Koyu; Jiang, Weihua

    2013-01-01

    High power sub-terahertz pulsed gyrotrons for Collective Thomson Scattering (CTS) diagnostics of fusion plasmas are being developed. The typical target parameters are: output power of 100-200 kW, operation frequency of 300 GHz, and pulsed length > 10 us. In order to support experimental development, numerical simulations were carried out by using Particle-In-Cell (PIC) code MAGIC. The oscillation mode of the electromagnetic radiation was selected as TE_1_5_,_2, for which the beam parameters and cavity dimensions were determined accordingly. The simulation results have showed maximum power of 144 kW at oscillation frequency of 292.80 GHz, with oscillation efficiency of 22.15%. (author)

  9. On variation in Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian of western Kazakhstan

    Science.gov (United States)

    Kennedy, William James

    2013-12-01

    Kennedy, W.J. 2013. On variation in Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian of western Kazakhstan Acta Geologica Polonica, 63(4), 443-468. Warszawa. An assemblage of 94 specimens of Schloenbachia varians (J. Sowerby, 1817) from the Lower Cenomanian Sharpeiceras schlueteri Subzone of the Mantelliceras mantelli Zone of the Besakty section in the Mangyshlak Mountains of western Kazakhstan includes 26 complete adults that range from to 59-174 mm in diameter. No size-related dimorphism was detected in the assemblage, which shows wide, continuous intraspecific variation. This is described in terms of five formae; from robust to gracile these are: ventriosa, varians sensu stricto, subtuberculata , intermedia, and subplana. The ratio of robust (ventriosa + varians sensu stricto) to gracile (subtuberculata + intermedia + subplana) individuals is 34% to 66%. The reference specimens of the formae and their synonyms are described and illustrated, and related to the Besakty material. The modification of adult body chamber ornament of all formae is documented, and Jakeiceras Cooper and Owen, 2011 is shown to be based on an adult of a passage form between forma subtuberculata and forma intermedia. The differences between Lower Cenomanian S. varians, lower Middle Cenomanian S. coupei (Brongniart, 1822), and upper Middle and lower Upper Cenomanian S. lymensis Spath, 1926b are described and illustrated.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  11. MAGY: An innovative high voltage-low current power supply for gyrotron

    International Nuclear Information System (INIS)

    Siravo, Ugo; Alex, Juergen; Bader, Michael; Carpita, Mauro; Fasel, Damien; Gavin, Serge; Perez, Albert

    2011-01-01

    From the electrical point of view, the body and the anode of high power gyrotrons behave as capacitive loads. A highly dynamic power supply is, therefore, hard to achieve. The MAGY concept (Modulator for the Anode of a triode type GYrotron) embodies an innovative solution to manage the capacitive current ensuring a very low ripple on the output voltage. It consists of a series of independent, bi-directional and regulated DC sources. Compared to existing topologies, this solution requires a smaller number of power modules. It avoids internal high frequency modulation and simultaneously offers high resolution of the output voltage and a wide range of operating scenarios.

  12. Control of generation spectrum of gyrotron with external reflection in mode of several longitudinal modes

    International Nuclear Information System (INIS)

    Rozental', R.M.; Ginzburg, N.S.; Zajtsev, N.I.; Ilyakov, E.V.; Kulagin, I.S.

    2006-01-01

    One studies possibility to control the spectrum of multiparticle generation in a gyrotron due to application of external reflections. It is shown that in self-modulation regimes of generation the radiation spectrum lines may be close to the resonance frequencies throughout electrodynamic system covering a part of output waveguide restricted by a reflector. Under the mentioned conditions variation of distance between mode frequencies and, respectively, period of self-modulation may be reached due to varying of position of the reflector. The theory deductions are supported by the results of experimental investigation into 30 GHz region relativistic gyrotron with external reflections [ru

  13. Numerical design and analysis of parasitic mode oscillations for 95 GHz gyrotron beam tunnel

    Science.gov (United States)

    Kumar, Nitin; Singh, Udaybir; Yadav, Vivek; Kumar, Anil; Sinha, A. K.

    2013-05-01

    The beam tunnel, equipped with the high lossy ceramics, is designed for 95 GHz gyrotron. The geometry of the beam tunnel is optimized considering the maximum RF absorption (ideally 100%) and the suppression of parasitic oscillations. The excitation of parasitic modes is a concerning problem for high frequency, high power gyrotrons. Considering the problem of parasitic mode excitation in beam tunnel, a detail analysis is performed for the suppression of these kinds of modes. Trajectory code EGUN and CST Microwave Studio are used for the simulations of electron beam trajectory and electromagnetic analysis, respectively.

  14. Numerical Simulation of MIG for 42 GHz, 200 kW Gyrotron

    Science.gov (United States)

    Singh, Udaybir; Bera, Anirban; Kumar, Narendra; Purohit, L. P.; Sinha, Ashok K.

    2010-06-01

    A triode type magnetron injection gun (MIG) of a 42 GHz, 200 kW gyrotron for an Indian TOKAMAK system is designed by using the commercially available code EGUN. The operating voltages of the modulating anode and the accelerating anode are 29 kV and 65 kV respectively. The operating mode of the gyrotron is TE03 and it is operated in fundamental harmonic. The simulated results of MIG obtained with the EGUN code are validated with another trajectory code TRAK.

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

    International Nuclear Information System (INIS)

    Stock, Andreas

    2013-01-01

    Within this thesis a parallelized, transient, three-dimensional, high-order discontinuous Galerkin Particle-in-Cell solver is developed and used to simulate the resonant cavity of a gyrotron. The high-order discontinuous Galerkin approach - a Finite-Element type method - provides a fast and efficient algorithm to numerically solve Maxwell's equations used within this thesis. Besides its outstanding dissipation and dispersion properties, the discontinuous Galerkin approach easily allows for using unstructured grids, as required to simulate complex-shaped engineering devices. The discontinuous Galerkin approach approximates a wavelength with significantly less degrees of freedom compared to other methods, e.g. Finite Difference methods. Furthermore, the parallelization capabilities of the discontinuous Galerkin framework are excellent due to the very local dependencies between the elements. These properties are essential for the efficient numerical treatment of the Vlasov-Maxwell system with the Particle-in-Cell method. This system describes the self-consistent interaction of charged particles and the electromagnetic field. As central application within this thesis gyrotron resonators are simulated with the discontinuous Galerkin Particle-in-Cell method on high-performance-computers. The gyrotron is a high-power millimeter wave source, used for the electron cyclotron resonance heating of magnetically confined fusion plasma, e.g. in the Wendelstein 7-X experimental fusion-reactor. Compared to state-of-the-art simulation tools used for the design of gyrotron resonators the Particle-in-Cell method does not use any significant physically simplifications w.r.t. the modelling of the particle-field-interaction, the geometry and the wave-spectrum. Hence, it is the method of choice for validation of current simulation tools being restricted by these simplifications. So far, the Particle-in-Cell method was restricted to be used for demonstration calculations only, because

  16. 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

    Within this thesis a parallelized, transient, three-dimensional, high-order discontinuous Galerkin Particle-in-Cell solver is developed and used to simulate the resonant cavity of a gyrotron. The high-order discontinuous Galerkin approach - a Finite-Element type method - provides a fast and efficient algorithm to numerically solve Maxwell's equations used within this thesis. Besides its outstanding dissipation and dispersion properties, the discontinuous Galerkin approach easily allows for using unstructured grids, as required to simulate complex-shaped engineering devices. The discontinuous Galerkin approach approximates a wavelength with significantly less degrees of freedom compared to other methods, e.g. Finite Difference methods. Furthermore, the parallelization capabilities of the discontinuous Galerkin framework are excellent due to the very local dependencies between the elements. These properties are essential for the efficient numerical treatment of the Vlasov-Maxwell system with the Particle-in-Cell method. This system describes the self-consistent interaction of charged particles and the electromagnetic field. As central application within this thesis gyrotron resonators are simulated with the discontinuous Galerkin Particle-in-Cell method on high-performance-computers. The gyrotron is a high-power millimeter wave source, used for the electron cyclotron resonance heating of magnetically confined fusion plasma, e.g. in the Wendelstein 7-X experimental fusion-reactor. Compared to state-of-the-art simulation tools used for the design of gyrotron resonators the Particle-in-Cell method does not use any significant physically simplifications w.r.t. the modelling of the particle-field-interaction, the geometry and the wave-spectrum. Hence, it is the method of choice for validation of current simulation tools being restricted by these simplifications. So far, the Particle-in-Cell method was restricted to be used for demonstration calculations only, because

  17. Numerical Simulation of Single-anode and Double-anode Magnetron Injection Guns for 127.5 GHz 1 MW Gyrotron

    Science.gov (United States)

    Singh, Udaybir; Kumar, Nitin; Kumar, Anil; Purohit, Laxmi Prasad; Sinha, Ashok Kumar

    2011-07-01

    This paper presents the design of two types of magnetron injection guns (MIG's) for 1 MW, 127.5 GHz gyrotron. TE24,8 mode has been chosen as the operating mode. In-house developed code MIGSYN has been used to estimate the initial gun parameters. The electron trajectory tracing program EGUN and in-house developed code MIGANS have been used to optimize the single-anode and the double-anode design for 80 kV, 40 A MIG. The parametric analysis of MIG has also been presented. The advantages and the disadvantages of each kind of configuration have been critically examined.

  18. Three-dimensional simulation of triode-type MIG for 1 MW, 120 GHz gyrotron for ECRH applications

    Science.gov (United States)

    Singh, Udaybir; Kumar, Nitin; Kumar, Narendra; Kumar, Anil; Sinha, A. K.

    2012-01-01

    In this paper, the three-dimensional simulation of triode-type magnetron injection gun (MIG) for 120 GHz, 1 MW gyrotron is presented. The operating voltages of the modulating anode and the accelerating anode are 57 kV and 80 kV respectively. The high order TE 22,6 mode is selected as the operating mode and the electron beam is launched at the first radial maxima for the fundamental beam-mode operation. The initial design is obtained by using the in-house developed code MIGSYN. The numerical simulation is performed by using the commercially available code CST-Particle Studio (PS). The simulated results of MIG obtained by using CST-PS are validated with other simulation codes EGUN and TRAK, respectively. The results on the design output parameters obtained by using these three codes are found to be in close agreement.

  19. 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.

  20. Generalized monitor unit calculation for the Varian enhanced dynamic wedge field

    International Nuclear Information System (INIS)

    Liu Chihray; Kim, Siyong; Kahler, Darren L.; Palta, Jatinder R.

    2003-01-01

    The generalized monitor unit (MU) calculation equation for the Varian enhanced dynamic wedge (EDW) is derived. The assumption of this MU calculation method is that the wedge factor of the EDW at the center of the field is a function of field size, the position of the center of the field in the wedge direction, and the final position of the moving jaw. The wedge factors at the center of the field in both symmetric and asymmetric fields are examined. The difference between calculated and measured wedge factors is within 1.0%. The method developed here is easy to implement. The only datum required in addition to the standard set of conventional physical wedge implementation data is the off-axis output factor for the open field in the reference condition. The off-center point calculation is also examined. For the off-center point calculation, the dose profile in the wedge direction for the largest EDW field is used to obtain the relative off-center ratio in any smaller wedge field. The accuracy of the off-center point calculation decreases when the point of calculation is too close to the field edge

  1. Multimegawatt relativistic harmonic gyrotron traveling-wave tube amplifier experiments

    International Nuclear Information System (INIS)

    Menninger, W.L.; Danly, B.G.; Temkin, R.J.

    1996-01-01

    The first multimegawatt harmonic relativistic gyrotron traveling-wave tube (gyro-twt) amplifier experiment has been designed, built, and tested. Results from this experimental setup, including the first ever reported third-harmonic gyro-twt results, are presented. Operation frequency is 17.1 GHz. Detailed phase measurements are also presented. The electron beam source is SNOMAD-II, a solid-state nonlinear magnetic accelerator driver with nominal parameters of 400 kV and 350 A. The flat-top pulsewidth is 30 ns. The electron beam is focused using a Pierce geometry and then imparted with transverse momentum using a bifilar helical wiggler magnet. Experimental operation involving both a second-harmonic interaction with the TE 21 mode and a third-harmonic interaction with the TE 31 mode, both at 17 GHz, has been characterized. The third-harmonic interaction resulted in 4-MW output power and 50-dB single-pass gain, with an efficiency of up to ∼8%. The best measured phase stability of the TE 31 amplified pulse was ±10 degree over a 9-ns period. The phase stability was limited because the maximum RF power was attained when operating far from wiggler resonance. The second harmonic, TE 21 had a peak amplified power of 2 MW corresponding to 40-dB single-pass gain and 4% efficiency. The second-harmonic interaction showed stronger superradiant emission than the third-harmonic interaction. Characterizations of the second- and third-harmonic gyro-twt experiments presented here include measurement of far-field radiation patterns, gain and phase versus interaction length, phase stability, and output power versus input power

  2. Development of EC technology in JAERI

    International Nuclear Information System (INIS)

    Sakamoto, Keishi; Takahashi, Koji; Kasugai, Atsushi; Hayashi, Kenichi; Ikeda, Yoshitaka; Kajiwara, Ken; Fujii, Tsuneyuki; Imai, Tsuyoshi; Kariya, Tsuyoshi; Mitsunaka, Yoshika

    2003-01-01

    Recent progress of electron cyclotron (EC) heating and current drive technologies in JAERI is reported. In 170 GHz gyrotron development, 0.9 MW/9.2 sec (efficiency: 43%), 0.5 MW/30 sec (46%), etc, have been demonstrated. As for 110 GHz gyrotron, 1 MW/5 sec and 1.2 MW/4.1 sec were obtained. Using four 110 GHz gyrotrons, a 3 MW power injection into JT- 60U plasma was carried out. In parallel, a launcher design and its development that includes neutron irradiation of the launcher components and a remote steering launcher are underway for ITER application. (authors)

  3. Efficient Low-Voltage Operation of a CW Gyrotron Oscillator at 233 GHz.

    Science.gov (United States)

    Hornstein, Melissa K; Bajaj, Vikram S; Griffin, Robert G; Temkin, Richard J

    2007-02-01

    The gyrotron oscillator is a source of high average power millimeter-wave through terahertz radiation. In this paper, we report low beam power and high-efficiency operation of a tunable gyrotron oscillator at 233 GHz. The low-voltage operating mode provides a path to further miniaturization of the gyrotron through reduction in the size of the electron gun, power supply, collector, and cooling system, which will benefit industrial and scientific applications requiring portability. Detailed studies of low-voltage operation in the TE(2) (,) (3) (,) (1) mode reveal that the mode can be excited with less than 7 W of beam power at 3.5 kV. During CW operation with 3.5-kV beam voltage and 50-mA beam current, the gyrotron generates 12 W of RF power at 233.2 GHz. The EGUN electron optics code describes the low-voltage operation of the electron gun. Using gun-operating parameters derived from EGUN simulations, we show that a linear theory adequately predicts the low experimental starting currents.

  4. The gyrotron - a natural source of high-power orbital angular momentum millimeter-wave beams

    Science.gov (United States)

    Thumm, M.; Sawant, A.; Choe, M. S.; Choi, E. M.

    2017-08-01

    Orbital angular momentum (OAM) of electromagnetic-wave beams provides further diversity to multiplexing in wireless communication. The present report shows that higher-order mode gyrotrons are natural sources of high-power OAM millimeter (mm) wave beams. The well-defined OAM of their rotating cavity modes operating at near cutoff frequency has been derived by photonic and electromagnetic wave approaches.

  5. Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas

    2016-01-01

    -tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  6. Analysis of daily quality assurance tests for tomotherapy and two Varian linear accelerators - three months review

    International Nuclear Information System (INIS)

    Kushwaha, Pratishtha; Jaiswal, Deeksha; Dheera, A.; Upreti, Udita; Chaudhari, Suresh; Kinhikar, Rajesh; Deshpande, Deepak; Shrivastava, Shyam

    2016-01-01

    Daily quality assurance (QA) for high precision radiotherapy equipments is very important to maintain the mechanical and dosimetric accuracy for patient treatments. Gross deviations in these parameters may have an adverse impact on the delivery of the treatments to patients. We report the results of daily QA tests performed over a period of three months for two Varian linear accelerators and a Tomotherapy machine

  7. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    Science.gov (United States)

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Experimental considerations concerning the velocity measurement of the relativistic electron beam in a gyrotron by means of Thomson scattering

    International Nuclear Information System (INIS)

    Siegrist, M.R.; Soumagne, G.; Tran, M.Q.

    1992-11-01

    The feasibility of Thomson scattering to determine the beam velocity in a gyrotron has been analyzed and preliminary experiments to implement such a system on our 100 GHz quasi-optical gyrotron are reported. Although the project had to be abandoned due to technical problems, the conclusions are that for the 90 o scattering arrangement discussed it should be possible to determine at least one velocity component with an acceptable signal-to-noise ratio. (author) 11 figs., 10 refs

  9. 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.

  10. Analisis Throughput Varian TCP Pada Model Jaringan WiMAX

    Directory of Open Access Journals (Sweden)

    Medi Taruk

    2016-07-01

    Full Text Available Transmission Control Protocol (TCP is a protocol that works at the transport layer of the OSI model. TCP was originally designed more destined for a wired network. However, to meet the need for the development of a very fast network technology based on the needs of the use by the user, it needs further development to the use of TCP on wireless devices. One implementation of a wireless network based on Worldwide Interoperability for Microwave Access (WiMAX network is a model that offers a variety advantage, particularly in terms of access speed. In this case, use NS-2 to see throughput at TCP variants tested, namely TCP-Tahoe, TCP-Reno, TCP-Vegas, and TCP-SACK over WiMAX network model, with few observations scenarios. The first is a look at each of these variants throughput of TCP when only one particular variant of the work in the network. Second observe all variants of TCP throughput at the same time and have the equivalent QoS, but with the possibility of a small congestion based on the capacity of the link is made sufficient. Third observed throughput with multi congestion. In WiMAX network has scheduling services are UGS, rtPS and ertPS using UDP protocol and nrtPS and BE using the TCP Protocol. By using the software network simulator (NS-2 to obtain performance comparison TCP protocol-based services on the WiMAX network with QoS parameters are throughput, packet loss, fairness and time delay.

  11. PERBEDAAN MUSIM TANAM TERHADAP PERFORMA BUDIDAYA EMPAT VARIAN RUMPUT LAUT EUCHEUMATOIDS DI TELUK GERUPUK, NUSA TENGGARA BARAT

    Directory of Open Access Journals (Sweden)

    Erlania Erlania

    2014-08-01

    Full Text Available Musim tanam rumput laut di perairan Teluk Gerupuk dikelompokkan menjadi musim produktif dan non-produktif. Penelitian ini bertujuan untuk menganalisis perbedaan performa budidaya dari empat varian rumput laut: Kappaphycus alvarezii varian Tambalang dan Maumere, Eucheuma denticulatum, dan K. striatum yang dibudidayakan di perairan Teluk Gerupuk dengan metode long line pada musim tanam yang berbeda. Pengamatan terhadap parameter performa budidaya meliputi laju pertumbuhan harian, pertambahan biomassa, dan produksi rumput laut, yang dilakukan setiap 15 hari sekali selama masa budidaya yaitu 45 hari per siklus. Pengamatan dilakukan selama tiga siklus tanam dari bulan Juli-Desember. Analisis ragam (ANOVA dengan rancangan acak lengkap faktorial dan uji lanjut Tukey Test dilakukan untuk mengetahui pengaruh perbedaan varian rumput laut dan periode musim tanam terhadap parameter yang diamati. Hasil penelitian menunjukkan bahwa musim tanam (produktif dan non-produktif merupakan salah satu aspek penting yang berpengaruh nyata terhadap performa budidaya rumput laut (P<0,05. Dari keempat varian yang dibudidayakan, E. denticulatum merupakan varian yang memiliki performa terbaik yang berbeda nyata dengan ketiga varian lainnya (P<0,05, baik pada musim produktif maupun musim non-produktif. Pemilihan varian rumput laut yang tepat dengan tingkat pertumbuhan dan daya adaptasi yang lebih baik terhadap perbedaan kondisi lingkungan merupakan salah satu kunci keberhasilan dan keberlanjutan budidaya rumput laut.

  12. Experimental validation of neutron activation simulation of a varian medical linear accelerator.

    Science.gov (United States)

    Morato, S; Juste, B; Miro, R; Verdu, G; Diez, S

    2016-08-01

    This work presents a Monte Carlo simulation using the last version of MCNP, v. 6.1.1, of a Varian CLinAc emitting a 15MeV photon beam. The main objective of the work is to estimate the photoneutron production and activated products inside the medical linear accelerator head. To that, the Varian LinAc head was modelled in detail using the manufacturer information, and the model was generated with a CAD software and exported as a mesh to be included in the particle transport simulation. The model includes the transport of photoneutrons generated by primary photons and the (n, γ) reactions which can result in activation products. The validation of this study was done using experimental measures. Activation products have been identified by in situ gamma spectroscopy placed at the jaws exit of the LinAc shortly after termination of a high energy photon beam irradiation. Comparison between experimental and simulation results shows good agreement.

  13. Analysis of output trends from Varian 2100C/D and 600C/D accelerators

    International Nuclear Information System (INIS)

    Grattan, M W D; Hounsell, A R

    2011-01-01

    Analysis of Varian linear accelerator output trends is reported. Two groups, consisting of four matched Varian 2100C/D and four matched Varian 600C/D accelerators, with different designs of monitor chamber, have been investigated and the data acquired from regular calibrated ion chamber/electrometer measurements of the output performance of the eight accelerators analysed. The trend of machine output with time, having removed the effect of adjusting the monitor chamber response, was compared on a monthly and annual basis for monitor chambers with ages ranging between 1 year and 7 years. The results indicate that the response is generally consistent within each set of accelerators with different monitor chamber designs. Those used in a Varian 600C/D machine result in a reduction in measured output over time, with an average monthly reduction of 0.35 ± 0.09% over the course of the first 4 years of use. The chambers used in a 2100C/D accelerator result in an increase in measured output over time, with an average monthly increase of 0.26 ± 0.09% over the course of the first 4 years of use. The output increase then reduces towards the end of this period of time, with the average monthly change falling to -0.03 ± 0.02% for the following 3 years. The output response trend was similar for all clinical energies used on the 2100C/D accelerators--6, 15 MV x-ray beams, and 4, 6, 9, 12, 16 and 20 MeV electron beams. By tracking these changes it has been possible to predict the response over time to allow appropriate adjustments in monitor chamber response to maintain a measured accelerator output within tolerance and give confidence in performance. It has also provided data to indicate the need for planned preventative intervention and indicate if the monitor chamber response is behaving as expected. (note)

  14. The Use of a 28 GHz Gyrotron for EBW Startup Experiments on MAST

    Science.gov (United States)

    Caughman, J. B.; Bigelow, T. S.; Diem, S. J.; Peng, Y. K. M.; Rasmussen, D. A.; Shevchenko, V.; Hawes, J.; Lloyd, B.

    2009-11-01

    The use of electron Bernstein waves for non-inductive plasma current startup in MAST has recently been demonstrated [1]. The injection of 100 kW at 28 GHz generated plasma currents of up to 33 kA without the use of solenoid flux, and limited solenoid assist resulted in up to 55 kA of plasma current. A higher power 28 GHz gyrotron, with power levels of up to 300 kW for 0.5 seconds, is currently being commissioned. It is being used to investigate the scaling of startup current with microwave power and power profile as a function of time. Power modulation experiments are also being explored. Gyrotron performance and experimental results will be presented. [4pt] [1] V. Shevchenko, et al., Proceedings of the 15^th Joint Workshop on ECE and ECRH, Yosimite, USA, p. 68 (2009)

  15. RF Behavior of Cylindrical Cavity Based 240 GHz, 1 MW Gyrotron for Future Tokamak System

    Science.gov (United States)

    Kumar, Nitin; Singh, Udaybir; Bera, Anirban; Sinha, A. K.

    2017-11-01

    In this paper, we present the RF behavior of conventional cylindrical interaction cavity for 240 GHz, 1 MW gyrotron for futuristic plasma fusion reactors. Very high-order TE mode is searched for this gyrotron to minimize the Ohmic wall loading at the interaction cavity. The mode selection process is carried out rigorously to analyze the mode competition and design feasibility. The cold cavity analysis and beam-wave interaction computation are carried out to finalize the cavity design. The detail parametric analyses for interaction cavity are performed in terms of mode stability, interaction efficiency and frequency. In addition, the design of triode type magnetron injection gun is also discussed. The electron beam parameters such as velocity ratio and velocity spread are optimized as per the requirement at interaction cavity. The design studies presented here confirm the realization of CW, 1 MW power at 240 GHz frequency at TE46,17 mode.

  16. Design and simulation of a ~390 GHz seventh harmonic gyrotron using a large orbit electron beam

    Science.gov (United States)

    Li, Fengping; He, Wenlong; Cross, Adrian W.; Donaldson, Craig R.; Zhang, Liang; Phelps, Alan D. R.; Ronald, Kevin

    2010-04-01

    A ~390 GHz harmonic gyrotron based on a cusp electron gun has been designed and numerically modelled. The gyrotron operates at the seventh harmonic of the electron cyclotron frequency with the beam interacting with a TE71 waveguide mode. Theoretical as well as numerical simulation results using the 3D particle-in-cell code MAGIC are presented. The cusp gun generated an axis-encircling, annular shaped electron beam of energy 40 keV, current 1.5 A with a velocity ratio α of 3. Smooth cylindrical waveguides have been studied as the interaction cavities and their cavity Q optimized for 390 GHz operation. In the simulations ~600 W of output power at the design frequency has been demonstrated.

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

    International Nuclear Information System (INIS)

    Kreischer, K.E.

    1981-01-01

    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

  18. Experimental results for a 1.5 MW, 110 GHz gyrotron oscillator with reduced mode competition

    Science.gov (United States)

    Choi, E. M.; Marchewka, C. D.; Mastovsky, I.; Sirigiri, J. R.; Shapiro, M. A.; Temkin, R. J.

    2006-02-01

    A new result from a 110GHz gyrotron at MIT is reported with an output power of 1.67MW and an efficiency of 42% when operated at 97kV and 41A for 3μs pulses in the TE22,6 mode. These results are a major improvement over results obtained with an earlier cavity design, which produced 1.43MW of power at 37% efficiency. These new results were obtained using a cavity with a reduced output taper angle and a lower ohmic loss when compared with the earlier cavity. The improved operation is shown experimentally to be the result of reduced mode competition from the nearby TE19,7 mode. The reduced mode competition agrees well with an analysis of the startup scenario based on starting current simulations. The present results should prove useful in planning long pulse and CW versions of the 110GHz gyrotron.

  19. Experimental results for a 1.5 MW, 110 GHz gyrotron oscillator with reduced mode competition

    International Nuclear Information System (INIS)

    Choi, E.M.; Marchewka, C.D.; Mastovsky, I.; Sirigiri, J.R.; Shapiro, M.A.; Temkin, R.J.

    2006-01-01

    A new result from a 110 GHz gyrotron at MIT is reported with an output power of 1.67 MW and an efficiency of 42% when operated at 97 kV and 41 A for 3 μs pulses in the TE 22,6 mode. These results are a major improvement over results obtained with an earlier cavity design, which produced 1.43 MW of power at 37% efficiency. These new results were obtained using a cavity with a reduced output taper angle and a lower ohmic loss when compared with the earlier cavity. The improved operation is shown experimentally to be the result of reduced mode competition from the nearby TE 19,7 mode. The reduced mode competition agrees well with an analysis of the startup scenario based on starting current simulations. The present results should prove useful in planning long pulse and CW versions of the 110 GHz gyrotron

  20. Operation of a quasi-optical gyrotron with a gaussian output coupler

    Energy Technology Data Exchange (ETDEWEB)

    Hogge, J.P.; Tran, T.M.; Paris, P.J.; Tran, M.Q. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1996-03-01

    The operation of a 92 GHz quasi-optical gyrotron (QOG) having a resonator formed by a spherical mirror and a diffraction grating placed in -1 order Littrow mount is presented. A power of 150 kW with a gaussian output pattern was measured. The gaussian content in the output was 98% with less than 1% of depolarization. By optimizing the magnetic field at fixed frequency, a maximum efficiency of 15% was reached. (author) 12 figs., 2 tabs., 22 refs.

  1. Final Report for 'Gyrotron Design and Evaluation using New Particle-in-Cell Capability'

    International Nuclear Information System (INIS)

    Smithe, David N.

    2008-01-01

    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 and 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.

  2. Upgrade of a 30 kV/10 mA anode power supply for triode type gyrotron

    Energy Technology Data Exchange (ETDEWEB)

    Siravo, Ugo, E-mail: ugo.siravo@epfl.ch; Alberti, Stefano; Dubray, Jérémie; Fasel, Damien; Hogge, Jean-Philippe; Marlétaz, Blaise; Marmillod, Philippe; Perez, Albert; Silva, Miguel

    2015-10-15

    Highlights: • Triode type gyrotron is fed by 3 power supplies: the main, an anode PS(APS) and a heater. • This paper presents the upgrade of 3APS, supplied in 1999, that never fulfilled the specs. • The new working principle is very efficient, easy to implement, for a minimal cost. • Upgraded APS provides extended modulation capabilities, no overshoot and lowerripple. • This upgrade will allow exploring new operation regimes for the 3 TCV X3 gyrotrons. - The RF power of a gyrotron with a triode type magnetron-injection-gun (MIG) can be directly controlled via the voltage applied between its anode and its cathode. Hence, the performance of this type of gyrotron relies directly on the possibilities offered by the power supply controlling the anode to cathode voltage. For a system of gyrotrons connected to the same main high-voltage power supply, with a triode MIG one has the additional advantage of independently controlling each individual gyrotron. This paper presents the modifications brought to the three existing 30 kV/10 mA anode power supplies connected to the 500 kW/118 GHz/2s X3 gyrotrons operated on the TCV Tokamak. The new working principle based on phase-shift modulation (PSM) is described in detail. Experimental results obtained on dummy load are compared to simulations performed during the design phase. With respect to the initial working principle, the modulation frequency capability has been increased by a factor 10 reaching more than 5 kHz, whereas the output voltage ripple as well as the overshoot/undershoot have been significantly reduced.

  3. Update on the DIII-D ECH system: experiments, gyrotrons, advanced diagnostics, and controls

    Directory of Open Access Journals (Sweden)

    Lohr John

    2017-01-01

    Full Text Available The ECH system on DIII-D is continuing to be upgraded, while simultaneously being operated nearly daily for plasma experiments. The latest major hardware addition is a new 117.5 GHz gyrotron, which generated 1.7 MW for short pulses during factory testing. A new gyrotron control system based on Field Programmable Gate Array (FPGA technology with very high speed system data acquisition has significantly increased the flexibility and reliability of individual gyrotron operation. We have improved the performance of the fast mirror scanning, both by increasing the scan speeds and by adding new algorithms for controlling the aiming using commands generated by the Plasma Control System (PCS. The system is used for transport studies, ELM control, current profile control, non-inductive current generation, suppression of MHD modes, startup assist, plasma density control, and other applications. A program of protective measures, which has been in place for more than two years, has eliminated damage to hardware and diagnostics caused by overdense operation. Other activities not directly related to fusion research have used the ECH system to test components, study methods for improving production of semiconductor junctions and materials, and test the feasibility of using ground based microwave systems to power satellites into orbit.

  4. Update on the DIII-D ECH system: experiments, gyrotrons, advanced diagnostics, and controls

    Science.gov (United States)

    Lohr, John; Brambila, Rigoberto; Cengher, Mirela; Gorelov, Yuri; Grosnickle, William; Moeller, Charles; Ponce, Dan; Torrezan, Antonio; Ives, Lawrence; Reed, Michael; Blank, Monica; Felch, Kevin; Parisuaña, Claudia; LeViness, Alexandra

    2017-08-01

    The ECH system on DIII-D is continuing to be upgraded, while simultaneously being operated nearly daily for plasma experiments. The latest major hardware addition is a new 117.5 GHz gyrotron, which generated 1.7 MW for short pulses during factory testing. A new gyrotron control system based on Field Programmable Gate Array (FPGA) technology with very high speed system data acquisition has significantly increased the flexibility and reliability of individual gyrotron operation. We have improved the performance of the fast mirror scanning, both by increasing the scan speeds and by adding new algorithms for controlling the aiming using commands generated by the Plasma Control System (PCS). The system is used for transport studies, ELM control, current profile control, non-inductive current generation, suppression of MHD modes, startup assist, plasma density control, and other applications. A program of protective measures, which has been in place for more than two years, has eliminated damage to hardware and diagnostics caused by overdense operation. Other activities not directly related to fusion research have used the ECH system to test components, study methods for improving production of semiconductor junctions and materials, and test the feasibility of using ground based microwave systems to power satellites into orbit.

  5. Frequency-agile gyrotron for electron decoupling and pulsed dynamic nuclear polarization

    Science.gov (United States)

    Scott, Faith J.; Saliba, Edward P.; Albert, Brice J.; Alaniva, Nicholas; Sesti, Erika L.; Gao, Chukun; Golota, Natalie C.; Choi, Eric J.; Jagtap, Anil P.; Wittmann, Johannes J.; Eckardt, Michael; Harneit, Wolfgang; Corzilius, Björn; Th. Sigurdsson, Snorri; Barnes, Alexander B.

    2018-04-01

    We describe a frequency-agile gyrotron which can generate frequency-chirped microwave pulses. An arbitrary waveform generator (AWG) within the NMR spectrometer controls the microwave frequency, enabling synchronized pulsed control of both electron and nuclear spins. We demonstrate that the acceleration of emitted electrons, and thus the microwave frequency, can be quickly changed by varying the anode voltage. This strategy results in much faster frequency response than can be achieved by changing the potential of the electron emitter, and does not require a custom triode electron gun. The gyrotron frequency can be swept with a rate of 20 MHz/μs over a 670 MHz bandwidth in a static magnetic field. We have already implemented time-domain electron decoupling with dynamic nuclear polarization (DNP) magic angle spinning (MAS) with this device. In this contribution, we show frequency-swept DNP enhancement profiles recorded without changing the NMR magnet or probe. The profile of endofullerenes exhibits a DNP profile with a <10 MHz linewidth, indicating that the device also has sufficient frequency stability, and therefore phase stability, to implement pulsed DNP mechanisms such as the frequency-swept solid effect. We describe schematics of the mechanical and vacuum construction of the device which includes a novel flanged sapphire window assembly. Finally, we discuss how commercially available continuous-wave gyrotrons can potentially be converted into similar frequency-agile high-power microwave sources.

  6. Feasibility study of the EU home team on a 170 GHz 1 MW CW gyrotron for ECH on ITER

    International Nuclear Information System (INIS)

    Iatrou, C.T.; Kern, S.; Thumm, M.; Moebius, A.; Nickel, H.U.; Horajitra, P.; Wien, A.; Tran, T.M.; Bon Mardion, G.; Pain, M.; Tonon, G.

    1995-03-01

    The gyrotron system for ECH and burn control on ITER requires at least 50 MW of RF power at frequencies near 170 GHz operating in CW. To meet these requirements, high efficiency gyrotron tubes with ≥1 MW power output capability are necessary, as well as simple coupling to either a quasi-optical or waveguide transmission line. The paper reports the feasibility study on the design of an ITER-relevant gyrotron oscillator at 170 GHz, 1 MW CW employing a diode electron gun, an advanced internal quasi-optical converter, a cryogenically cooled single disk sapphire window, and a depressed potential collector. The operating mode selection and the cavity design is a compromise between many design constraints. (author) 18 figs., 6 tabs., 21 refs

  7. 110GHz-500kW long-pulse gyrotron with built-in quasi-optical mode converter

    International Nuclear Information System (INIS)

    Sakamoto, Keishi; Kariya, Tsuyoshi; Hayashi, Ken-ichi.

    1994-01-01

    We have designed, fabricated, and tested a 110 GHz-500 kW long-pulse gyrotron. The gyrotron incorporates a quasi-optical mode converter which transforms the oscillation mode, TE 22,2 , into a Gaussian radiation beam. The adoption of a built-in mode converter enabled us to design the electron beam collector so as to be capable of tolerating a 2 MW heat load. Attention was also paid to designing the gyrotron cavity and output window so as to permit long-pulse operations. In an experiment, we observed a maximum output power of 550 kW and achieved 1.3 s operation at a power level of 410 kW. (author)

  8. High-power microwave transmission and mode conversion program. Progress report, June 15, 1993--June 15, 1994

    International Nuclear Information System (INIS)

    Vernon, R.J.; Lorbeck, J.A.

    1994-06-01

    This report briefly discusses the following topics: (1) Quasi-optical converter design for Varian gyrotron SN 4.1; (2) Quasi-optical converter cold-test measurement; (3) Modification of geometrical-optics synthesized surfaces; (4)Diffraction synthesis; (5) Tapered dimpled launcher; (6) Work on Vlasov converter system for Varian gyrotron SN 4.1R; (7) Analysis of gyrotron spurious modes; (8) MIT code benchmarking; (9) Development of low-power efficiency test for Vlasov converters; (10) Investigation of optimal beam waist size and mode content for injection into a circular and rectangular corrugated waveguides; (11) The effect of corrugations on reduction of the fields at the wall of waveguides; (12) Shipping of a microwave scanner to Varian and further microwave scanner development; and (13) Code transferred to Varian

  9. Studying the induced radioactivity of a varian clinac 2100C/D accelerator

    International Nuclear Information System (INIS)

    Lu Feng; Li Hailiang; Deng Daping; Shang Yunying; Jing Zhongjun

    2008-01-01

    Objective: To Study the influences of dose, time, distance and irradiation mode on induced radioactivity by measuring a Varian Clinac 2100C/D accelerator. Methods: The induced radioactivity was measured in different dose, time, distance and irradiation mode by using of 450P model dosemeter. The results was analysed. Results: The induced radioactivity is direct ratio with dose, inverse ratio with time and distance. In different irradiation mode, the induced radioactivity is different. Conclusion: The induced radioactivity level of accelerator is related with dose, time, distance and irradiation mode. (authors)

  10. Collateral patient doses in the Varian 21iX radiotherapy Linac

    International Nuclear Information System (INIS)

    Barquero, R.; Castillo, A. del

    2008-01-01

    Full text: The radiotherapy aim is to irradiate the patient tumor cells while the doses in healthy tissue remains as low as possible. Nevertheless, when high photon energy accelerators are used, collateral undesired photon and neutron doses are always implied during the treatments and became more important with the new accelerators and techniques as IMRT. To assess secondary cancer risk outside the treatment volume as a long-term medical consequence of treatments, the total doses received by each patient outside the primary field during his treatment must be estimated. To achieve this purpose photon and neutron dose equivalents Hp(10) and H*(10) has been measured in a new Varian 21iX with maximum photon energy of 15 MV placed recently in our radiotherapy department. Three devices: 1) a neutron dose rate meter BERTHOLD LB 4111 calibrated recently in the German PTB laboratory, 2) a calibrated environmental pressurized photon ionization chamber (IC) VICTOREEN 450-PI n/s 1020, and 3) a calibrated personal electronic photon dosimeter GAMMACOM 4200M, were placed above the treatment couch outside the primary field while the Varian 21iX reference test were done. In particular the photon and neutron doses in the couch were measured while a water phantom was irradiated during automatic beam data acquisition for a 15 MV beam. A complete set of measurements changing field size are made. These 15 MV results are compared with data measured previously by thermoluminescence and bubble dosimeters in the same facility for an Elekta Precise and a Siemens KDS both with maximum photon energy of 18 MV. From this the benefits in the patient collateral doses of decreasing the maximum treatment photon energy are discussed. The patient doses obtained in the Varian 21iX had values that go from 80 to 800 uSv per treatment Gray. As the Varian 21iX therapy Linac is operated in pulsed mode with short pulse length the discussion of the results includes: 1. The correction of dead time in the GM

  11. Monte Carlo simulation of the Varian Clinac 600C accelerator using dynamic wedges; Simulacao Monte Carlo do acelerador Varian Clinac 600C utilizando cunhas dinamicas

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, S. [Universidade da Beira Interior (UBI), Covilha (Portugal); Chaves, A.; Lopes, M.C. [Instituto Portugues de Oncologia Doutor Francisco Gentil (IPO), Coimbra (Portugal); Peralta, L. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas (LIP), Lisboa (Portugal)]|[Universidade de Lisboa (Portugal). Faculdade de Ciencias

    2004-07-01

    The advent of linear accelerators (linac) with computer-controlled dynamic collimation systems and functional and anatomical imaging techniques allowed a more exact delimitation and localisation of the target volume. These advanced treatment techniques inevitably increase the complexity level of dose calculation because of the introduction of the temporal variable. On account of this, it is mandatory the usage of more accurate modelling techniques of the collimator components, as it is the case of Monte Carlo (MC) simulation, which has created an enormous interest in research and clinical practice. Because the patients bodies are not homogenous nor are their body surfaces plane and regular, the dose distribution may differ significantly from the standard distribution from the linac calibration. It is in the treatment planning systems, which include algorithms that are usually measured in homogeneous water phantoms specific for each correction that the dose distributions from each case are obtained. In a real treatment, exception made to superficial lesions, two or more radiation fields are used in order to obtain the recommended dose distributions. The simplest arrangement is made from two parallel and opposed fields that originate a homogeneous dose distribution in almost all the irradiated volume. The available resources are, for example, different types of energies and of radiation, the application of bolus, the protection of healthy structures, the usage of wedged filters and the application of dynamic wedges. A virtual or dynamic wedge, modelled through the movement of one of the jaws, when compared with a set of physical wedges offers an alternative calculation method of an arbitrary number of wedged fields, instead of the four traditional fields of 15 deg, 30 deg, 45 deg and 60 deg angle and obtained with physical wedges. The goal of this work consists in the study of the application of dynamic wedges in tailoring the radiation field by the Varian Clinac 600

  12. SU-F-T-262: Commissioning Varian Portal Dosimetry for EPID-Based Patient Specific QA in a Non-Aria Environment

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M; Knutson, N [Rhode Island Hospital, Providence RI (United States); University of Rhode Island, Kingston, RI (United States); University of Massachusetts Lowell, Lowell, MA (United States); Herrington, J [University of Rhode Island, Kingston, RI (United States); Price, M [Rhode Island Hospital, Providence RI (United States); University of Rhode Island, Kingston, RI (United States); Alpert Medical School of Brown University, Providence, RI (United States)

    2016-06-15

    Purpose: Development of an in-house program facilitates a workflow that allows Electronic Portal Imaging Device (EPID) patient specific quality assurance (QA) measurements to be acquired and analyzed in the Portal Dosimetry Application (Varian Medical Systems, Palo Alto, CA) using a non-Aria Record and Verify (R&V) system (MOSAIQ, Elekta, Crawley, UK) to deliver beams in standard clinical treatment mode. Methods: Initial calibration of an in-house software tool includes characterization of EPID dosimetry parameters by importing DICOM images of varying delivered MUs to determine linear mapping factors in order to convert image pixel values to Varian-defined Calibrated Units (CU). Using this information, the Portal Dose Image Prediction (PDIP) algorithm was commissioned by converting images of various field sizes to output factors using the Eclipse Scripting Application Programming Interface (ESAPI) and converting a delivered configuration fluence to absolute dose units. To verify the algorithm configuration, an integrated image was acquired, exported directly from the R&V client, automatically converted to a compatible, calibrated dosimetric image, and compared to a PDIP calculated image using Varian’s Portal Dosimetry Application. Results: For two C-Series and one TrueBeam Varian linear accelerators, gamma comparisons (global 3% / 3mm) of PDIP algorithm predicted dosimetric images and images converted via the inhouse system demonstrated agreement for ≥99% of all pixels, exceeding vendor-recommended commissioning guidelines. Conclusion: Combinations of a programmatic image conversion tool and ESAPI allow for an efficient and accurate method of patient IMRT QA incorporating a 3rd party R&V system.

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

    International Nuclear Information System (INIS)

    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.

    1991-01-01

    Los Alamos is investigating a number of high power microwave (HPM) 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 (to allow injection of a suitable fraction of the electron beam born in the gun into the amplifier structure), 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 than has been converted to-date in the extractor

  14. Stabilization of the potential multi-steady-state absolute instabilities in a gyrotron traveling-wave amplifier

    International Nuclear Information System (INIS)

    Du Chaohai; Liu Pukun

    2009-01-01

    The problem of spurious oscillations induced by absolute instabilities is the most challenging one that hinders the development of the millimeter-wave gyrotron traveling-wave amplifiers (gyro-TWTs). A spurious oscillation exists as a high order axial mode (HOAM) in the interaction circuit. This paper is devoted to demonstrating the complicated steady states of these HOAMs and exploring corresponding techniques to stabilize these potential multi-steady-state absolute instabilities. The stability-oriented design principle is conveyed in a start-to-end design flow of a Ka-band TE 11 mode gyro-TWT. Strong magnetic tapering near the downstream port, which is capable of cutting short the effective interaction circuit of a spurious oscillation and simultaneously boosting the amplification performance, is for the first time proposed to further improve the system stability. It is also found that an ideal prebunched electron beam in the linear stage is the necessary condition to efficient amplification in the nonlinear stage, suggesting that it is feasible to design a stable prebunching stage to replace the distributed-loss-loaded linear stage. The stability-oriented design principle provides more explicit reference for future design of a zero-drive stable gyro-TWT.

  15. Simultaneous Stabilization of Gyrotron Frequency and Power by PID Double Feedback Control on the Acceleration and Anode Voltages

    Science.gov (United States)

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

    2017-07-01

    In this paper, we present the results of simultaneous stabilization of both the frequency and the output power by a double PID feedback control on the acceleration and anode voltages in the 460-GHz gyrotron FU CW GVI, also known as "Gyrotron FU CW GO-1" (according to the nomenclature adopted at Osaka University). The approach used in the experiments is based on the modulation of the cyclotron frequency and the pitch factor (velocity ratio) of the electron beam by varying the acceleration and the anode voltages, respectively. In a long-term experiment, the frequency and power stabilities were made to be better than ±10-6 and ±1%, respectively.

  16. The growth of Micrococcus varians by utilizing sugar cane blackstrap molasses as substrate

    Directory of Open Access Journals (Sweden)

    Miranda Luís A. S.

    1999-01-01

    Full Text Available Comparative studies on the growth of Micrococcus varians were carried out in BHI culture medium (control as well as in a culture medium with 2% diluted sugar cane blackstrap molasses, enriched with 0.1% yeast extract. The experiment was conducted with three samples of the experimental and control media in a 5 liter fermentor with working volume of 3.5 liters, continuous agitation (150 rpm, 35 ± 0.1°C temperature, 0.7 L air. l-1 medium. min -1, initial pH 7.0 ± 0.2, 24 hour fermentation period, and approximate inoculum of 6.0 log10 CFU/ml. Samples were collected at 2-hour intervals. Micrococcus varians grew in the two culture media studied, which confirms the experimental medium viability for the growth of this species. The final average concentration of biomass was higher in the control medium than in the experimental medium: 0.99 g.l-1 and 0.78 g.l-1, respectively. The final number of viable cells at the end of fermentation was 20.65 log10 CFU/ml for the control medium (BHI, while in the experimental medium the number of viable cells was 19.43 log10 CFU/ml. The consumption of total sugars was higher for the biomass in the control medium (79.78%, while only 50.53% was consumed for the experimental medium.

  17. Uptake and depuration of PCB-153 in edible shrimp Palaemonetes varians and human health risk assessment.

    Science.gov (United States)

    Grilo, T F; Cardoso, P G; Pato, P; Duarte, A C; Pardal, M A

    2014-03-01

    A medium-term mesocosm exposure study was conducted to elucidate bioaccumulation and depuration of polychlorinated biphenyl congener 153 (PCB-153) in edible shrimp Palaemonetes varians. Over the 15-day exposure period, shrimp under different exposure concentrations exhibited a significant increase in PCB-153 concentration compared with control organisms. Distinct bioaccumulation patterns and uptake rates were observed depending on the exposure concentrations. For low PCB-153 exposure levels (0.25μgL(-1)), accumulation followed a saturation model, reaching an apparent steady state after fifteen days exposure. For intermediate (2.5μgL(-1)) and high PCB-153 levels (25μgL(-1)), accumulation was faster and linear. In addition, the bioaccumulation rate was not proportional to PCB-153 concentration, and the bioaccumulation was higher at intermediate exposure concentrations. Regarding the depuration phase, P. varians lost up to 30% of PCB-153 after 72h and levels continued slowly to decrease until the end of the 30-d experimental period. However, PCB-153 levels in shrimp did not reach background values, and those exposed to moderate and high PCB-153 concentrations presented contamination levels much higher than the regulatory limit for human food consumption (75ngg(-1) ww for Σ6 PCB). Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Preliminary Determination of Activation Products for a Varian Truebeam Linear Accelerator.

    Science.gov (United States)

    Waller, Edward; Ram, Rohan; Steadman, Ian

    2017-09-01

    Medical linear accelerators used to treat various forms of cancers are operated at a number of different energies. A by-product of the high-energy photons produced by accelerators is activation of components within the machine itself and its surrounding bunker. The activation products pose radiological and regulatory challenges during the operation of the accelerator as well as when it is time for final decommissioning. The Varian TrueBeam is a new state-of-the-art linear accelerator now operating in the Canadian market. There is currently limited information on the production of its activation products and the resulting impacts on operation and decommissioning. In this paper, activation products in the Varian TrueBeam accelerator are experimentally determined by performing gamma spectroscopy using a portable high purity germanium detector. A total of 10 isotopes are identified for the conditions tested, which include Na, Al, Mn, Ni, Cu, Cu, Br, Sb, Sb, W. The half-lives of these isotopes range from 2.3 min to 60.2 d. These preliminary results indicate that a decommissioning case similar to other radiotherapy accelerators can be made.

  19. A Monte Carlo simulation framework for electron beam dose calculations using Varian phase space files for TrueBeam Linacs.

    Science.gov (United States)

    Rodrigues, Anna; Sawkey, Daren; Yin, Fang-Fang; Wu, Qiuwen

    2015-05-01

    To develop a framework for accurate electron Monte Carlo dose calculation. In this study, comprehensive validations of vendor provided electron beam phase space files for Varian TrueBeam Linacs against measurement data are presented. In this framework, the Monte Carlo generated phase space files were provided by the vendor and used as input to the downstream plan-specific simulations including jaws, electron applicators, and water phantom computed in the EGSnrc environment. The phase space files were generated based on open field commissioning data. A subset of electron energies of 6, 9, 12, 16, and 20 MeV and open and collimated field sizes 3 × 3, 4 × 4, 5 × 5, 6 × 6, 10 × 10, 15 × 15, 20 × 20, and 25 × 25 cm(2) were evaluated. Measurements acquired with a CC13 cylindrical ionization chamber and electron diode detector and simulations from this framework were compared for a water phantom geometry. The evaluation metrics include percent depth dose, orthogonal and diagonal profiles at depths R100, R50, Rp, and Rp+ for standard and extended source-to-surface distances (SSD), as well as cone and cut-out output factors. Agreement for the percent depth dose and orthogonal profiles between measurement and Monte Carlo was generally within 2% or 1 mm. The largest discrepancies were observed within depths of 5 mm from phantom surface. Differences in field size, penumbra, and flatness for the orthogonal profiles at depths R100, R50, and Rp were within 1 mm, 1 mm, and 2%, respectively. Orthogonal profiles at SSDs of 100 and 120 cm showed the same level of agreement. Cone and cut-out output factors agreed well with maximum differences within 2.5% for 6 MeV and 1% for all other energies. Cone output factors at extended SSDs of 105, 110, 115, and 120 cm exhibited similar levels of agreement. We have presented a Monte Carlo simulation framework for electron beam dose calculations for Varian TrueBeam Linacs. Electron beam energies of 6 to 20 MeV for open and collimated

  20. The upgrade of the DIII-D EC system using 120 GHz ITER gyrotrons

    International Nuclear Information System (INIS)

    Callis, R.W.; Lohr, J.; Gorelov, I.A.; Ponce, D.; Kajiwara, K.; Tooker, J.F.

    2005-01-01

    The planned growth in the EC system on DIII-D over the next few years requires the installation of two depressed collector gyrotrons, a high voltage power supply, two low loss transmission lines, and the required support equipment. This new DIII-D EC equipment could be made identical to the ITER EC system requirements. By building the DIII-D hardware to the ITER specifications, it will allow ITER to gain beneficial prototyping experience on a working tokamak, prior to committing to building the hardware for delivery to ITER

  1. Study of a high-order-mode gyrotron traveling-wave amplifier

    International Nuclear Information System (INIS)

    Chiu, C. C.; Tsai, C. Y.; Kao, S. H.; Chu, K. R.; Barnett, L. R.; Luhmann, N. C. Jr.

    2010-01-01

    Physics and performance issues of a TE 01 -mode gyrotron traveling-wave amplifier are studied in theory. For a high order mode, absolute instabilities on neighboring modes at the fundamental and higher cyclotron harmonic frequencies impose severe constraints to the device capability. Methods for their stabilization are outlined, on the basis of which the performance characteristics are examined in a multidimensional parameter space under the marginal stability criterion. The results demonstrate the viability of a high-order-mode traveling-wave amplifier and provide a roadmap for design tradeoffs among power, bandwidth, and efficiency. General trends are observed and illustrated with specific examples.

  2. DC space-charge induced frequency up-shift in a quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Tran, M.Q.; Tran, T.M.

    1990-10-01

    Recent experiments on a 100GHz quasi-optical gyrotron have shown that for a large resonator set-up the observed frequency up-shift between the starting current and a current of 10A corresponds to a shift of 4-5 longitudinal modes. In this Letter it is shown that the interpretation of this frequency up-shift should involve the current dependent electron beam voltage depression in the beam tunnel and the interaction region for both the single-mode and multi-mode time evolution codes. (author) 7 refs., 5 figs., 1 tab

  3. Design of 84 Ghz, 500 kW gyrotron for ECRH application

    International Nuclear Information System (INIS)

    Singh, Udaybir; Nitin Kumar; Anil Kumar; Rao, R.R.; Sinha, A.K.

    2013-01-01

    The design and numerical simulation of the 84 GHz gyrotron, are performed for first harmonic operation. TE 10,4 is selected as the operating mode after the rigorous analysis of several TE modes. Then the interaction cavity geometrical parameters are optimized on the basis of cold cavity simulations and Q factor calculation. The electron beam parameters are optimized in the beam-wave interaction simulations using Particle-in-Cell (PIC) code MAGIC. The triode-type magnetron injection gun with the accelerating voltage 70 kV, the beam current 10 A and the maximum transverse velocity spread less than 5% is designed. (author)

  4. Experimental measurements of competition between fundamental and second harmonic emission in a quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Pedrozzi, M.; Tran, M.Q.; Hogge, J.P.; Tran, T.M.; Muggli, P.; Joedicke, B.; Mathews, H.G.

    1990-04-01

    A quasi-optical gyrotron (QOG) designed for operation at the fundamental (Ω ce ≅100 GHz) exhibits simultaneous emission at Ω ce and 2Ω ce (second harmonic). For a beam current of 4 A, 20% of the total RF power is emitted at the second harmonic. The experimental measurements show that the excitation of the second harmonic is only possible when the fundamental is present. The frequency of the second harmonic is locked by the frequency of the fundamental. Experimental evidence shows that when the second harmonic is not excited, total efficiency is enhanced. (author) 6 refs., 5 figs., 1 tab

  5. Design and experimental investigation of a second harmonic 20 kW class 28 GHz gyrotron for evaluation of new emitter technologies

    Energy Technology Data Exchange (ETDEWEB)

    Malygin, Anton

    2016-07-01

    Gyrotrons are high-power mm-wave tubes. Here, the design, construction and experimental investigation of a 20 kW, 28 GHz gyrotron (2nd harmonic) are reported. This tube was designed to evaluate new emitters for future highly efficient and reliable fusion gyrotrons and for material processing applications. Following experimental results have been achieved in CW operation: 22.5 kW output power at 23.4 kV electron beam voltage and 2.23 A beam current with the world record efficiency of 43 %.

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

    International Nuclear Information System (INIS)

    Darbos, C.; Bouquey, F.; Lambert, R.; Magne, R.; Traisnel, E.; Arnold, A.; Prinz, H. O.; Thumm, M.; Hogge, J. P.; Lievin, C.

    2007-01-01

    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

  7. Novel dielectric photonic-band-gap resonant cavity loaded in a gyrotron

    International Nuclear Information System (INIS)

    Chen Xiaoan; Liu Gaofeng; Tang Changjian

    2010-01-01

    A novel resonant cavity composed of a periodic, multilayer, dielectric photonic crystal is proposed. Using the transfer matrix method and the Bloch theorem for periodic systems, an analysis on the band-gap property of such a structure is made, and the basic electromagnetic property of the photonic-band-gap resonant cavity (PBGC) is preliminarily exhibited. The theoretical studies and the cold cavity simulation results obtained from a high-frequency structure simulator are presented. On the basis of the present research, such a PBGC is quite similar to the two-dimensional PBGC made of triangular lattices of metal rods with a defect at its centre, in which a frequency selectivity is similarly demonstrated. Because of its unique electromagnetic property, the cavity has many promising applications in active and passive devices operating in the millimetre, sub-millimetre, and even THz wave range. As a specific application, the feasibility of substituting the traditional cylindrical resonant cavity loaded in a gyrotron for a dielectric PBGC to achieve a transverse high-order operation is discussed under the consideration of the electromagnetic features of the cavity. The study shows the great potential value of such a cavity for gyrotron devices.

  8. First experimental results of the LAP/INPE (Plasma Associated Lab) gyrotron

    International Nuclear Information System (INIS)

    Barroso, J.J.; Rossi, J.O.; Castro, P.J.; Correa, R.A.; Montes, A.; Ludwig, G.O.; Idehara, T.; Ogawa, I.

    1994-01-01

    The design and operation of a high power pulsed gyrotron are reported. A magnetron injection gun generates a 5 A, 50 keV helical laminar electron beam with a pitch ratio of 1.5. The electron beam is then placed on the second radial maximum of the T E 02 nominal mode in the resonant cavity. The magnet system comprises three independent water-cooled solenoids located in the gun, cavity and collector regions, consisting of split pair magnets with the field direction vertical. The resonator is a weakly tapered waveguide with a straight section of 0.5 cm in length, a down taper angle of 0.8 0 and an up taper angle of 5 0 The gyrotron runs in pulsed regime with a 20μs pulse length at a frequency repetition rate of 10 Hz and during operation the pressure in the tube is ordinarily less than 4.0 X 10 -7 Torr. Several TE modes were detected over the magnetic field range 9.5 to 12.5 kG and the measured resonant frequencies (29.0 to 32.0 GHz) showed to be in close agreement with the self-consistent calculated values. Experiments are currently under way to measure the absolute output power and to identify the modes through field pattern measurement techniques. (author). 3 refs, 3 figs

  9. 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.

  10. TU-AB-BRC-05: Creation of a Monte Carlo TrueBeam Model by Reproducing Varian Phase Space Data

    International Nuclear Information System (INIS)

    O’Grady, K; Davis, S; Seuntjens, J

    2016-01-01

    Purpose: To create a Varian TrueBeam 6 MV FFF Monte Carlo model using BEAMnrc/EGSnrc that accurately reproduces the Varian representative dataset, followed by tuning the model’s source parameters to accurately reproduce in-house measurements. Methods: A BEAMnrc TrueBeam model for 6 MV FFF has been created by modifying a validated 6 MV Varian CL21EX model. Geometric dimensions and materials were adjusted in a trial and error approach to match the fluence and spectra of TrueBeam phase spaces output by the Varian VirtuaLinac. Once the model’s phase space matched Varian’s counterpart using the default source parameters, it was validated to match 10 × 10 cm"2 Varian representative data obtained with the IBA CC13. The source parameters were then tuned to match in-house 5 × 5 cm"2 PTW microDiamond measurements. All dose to water simulations included detector models to include the effects of volume averaging and the non-water equivalence of the chamber materials, allowing for more accurate source parameter selection. Results: The Varian phase space spectra and fluence were matched with excellent agreement. The in-house model’s PDD agreement with CC13 TrueBeam representative data was within 0.9% local percent difference beyond the first 3 mm. Profile agreement at 10 cm depth was within 0.9% local percent difference and 1.3 mm distance-to-agreement in the central axis and penumbra regions, respectively. Once the source parameters were tuned, PDD agreement with microDiamond measurements was within 0.9% local percent difference beyond 2 mm. The microDiamond profile agreement at 10 cm depth was within 0.6% local percent difference and 0.4 mm distance-to-agreement in the central axis and penumbra regions, respectively. Conclusion: An accurate in-house Monte Carlo model of the Varian TrueBeam was achieved independently of the Varian phase space solution and was tuned to in-house measurements. KO acknowledges partial support by the CREATE Medical Physics Research

  11. Source to Skin Distance (SSD) Characteristics from Varian CX Linear Accelerator

    Science.gov (United States)

    Bahari Nurdin, Wira; Purnomo, Aji; Dewang, Syamsir

    2018-03-01

    This study aims to describe the characteristics of the source to skin distance (SSD) of Varian CX linear accelerator (LINAC) using the X-ray beam of 6 MV and 10 MV. The variation of the source to the SSD are 90, 100 and 110 cms; the depth of the water phantom used are 5, 10, 15, 20, and 25 cms, respectively. The depth of the water phantom was created for analysis of percentage depth dose (PDD) and profile dose. It can be concluded from the tests that from the measured SSD, SSD of 110 cm with the depth water phantom of 20-25 cm for energy beam of 6 MV and at all levels of depth for 10 MV energy corresponding tolerance limits to be used in clinical radiotherapy. For the SSD 90 and 100, the values beam symmetry and flatness obtained slightly beyond the limits of tolerance.

  12. TU-FG-201-05: Varian MPC as a Statistical Process Control Tool

    International Nuclear Information System (INIS)

    Carver, A; Rowbottom, C

    2016-01-01

    Purpose: Quality assurance in radiotherapy requires the measurement of various machine parameters to ensure they remain within permitted values over time. In Truebeam release 2.0 the Machine Performance Check (MPC) was released allowing beam output and machine axis movements to be assessed in a single test. We aim to evaluate the Varian Machine Performance Check (MPC) as a tool for Statistical Process Control (SPC). Methods: Varian’s MPC tool was used on three Truebeam and one EDGE linac for a period of approximately one year. MPC was commissioned against independent systems. After this period the data were reviewed to determine whether or not the MPC was useful as a process control tool. Analyses on individual tests were analysed using Shewhart control plots, using Matlab for analysis. Principal component analysis was used to determine if a multivariate model was of any benefit in analysing the data. Results: Control charts were found to be useful to detect beam output changes, worn T-nuts and jaw calibration issues. Upper and lower control limits were defined at the 95% level. Multivariate SPC was performed using Principal Component Analysis. We found little evidence of clustering beyond that which might be naively expected such as beam uniformity and beam output. Whilst this makes multivariate analysis of little use it suggests that each test is giving independent information. Conclusion: The variety of independent parameters tested in MPC makes it a sensitive tool for routine machine QA. We have determined that using control charts in our QA programme would rapidly detect changes in machine performance. The use of control charts allows large quantities of tests to be performed on all linacs without visual inspection of all results. The use of control limits alerts users when data are inconsistent with previous measurements before they become out of specification. A. Carver has received a speaker’s honorarium from Varian

  13. 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.; Griffin, Robert G.; Barnes, Alexander B.

    2012-01-01

    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 magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE11,2,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:23761938

  14. Fusion development and technology

    International Nuclear Information System (INIS)

    Montgomery, D.B.

    1991-01-01

    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

  15. Implementation of the program of quality control of the system on-board imager of varian: initial assessment; Puesta en marcha del programa de control de calidad del sistema on-board imager de varian: evaluacion inicial

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Martin, I.; Ruiz Morales, C.; Lopez Sanchez, F.; Tobarra Gonzalez, B. M.

    2013-07-01

    This work aims to present evidence that are part of our quality control system on-board Imager of Varian, elaborated from recommendations and national and international protocols, as well as a first assessment of the results obtained to date. (Author)

  16. Modelling of a linear accelerator VARIAN 600 C/D for dosimetric study using the Monte Carlo Method

    International Nuclear Information System (INIS)

    Cancino, Jorge Luis Batista

    2016-01-01

    Based on the high availability of low energy linear accelerators in Brazil and with the goal of developing a reliable tool for dose distribution calculations in radiotherapy; this research aims to validate a linear accelerator head model using MCNP Monte Carlo code. The Varian 600 C/D linear accelerator installed at the Hospital São João de is taken as reference. The main components of the linear accelerator head were simulated based on detailed information of the manufacturer. In order to calculate dose distribution, a water phantom with dimensions of 30 x 30 x 30 cm 3 was simulated and placed at 100 cm of source-surface distance. A monoenergetic electron beam of 6,3 MeV was considered as a source. The number of primary particles used in the simulation was 10 8 . A Phase-Space Surface was used to scoring the photon spectrum below the tungsten target. Others two were placed in the model in order to reduce computational time and improve statistical accuracy. In order to validate the developed model, the X-ray spectrum generated by Bremsstrahlung was calculated and analyzed. Furthermore, the results of percentage depth doses and beam profiles calculations were compared with available measurements. The MCNP calculations results were compared to measurement showing good agreement between them. The comparison between MCNP calculations and measurement of PDD showed reasonable coherence at build-up region. The results were in an acceptable interval of confidence at the flat region of beam profiles comparison for three different field sizes. In this work, we compared MCNP calculations to experimental data in order to validate the developed LINAC head model. The results showed a good agreement according to the recommended criteria. The developed model was validated as an accurate tool for LINAC quality control procedures. (author)

  17. Application of halophilic nuclease H of Micrococcus varians subsp. halophilus to commercial production of flavoring agent 5'-GMP.

    Science.gov (United States)

    Kamekura, M; Hamakawa, T; Onishi, H

    1982-01-01

    RNA was degraded at 60 degrees C for 24 h by halophilic nuclease H in supernatants from broth cultures of Micrococcus varians subsp. halophilus containing 12% NaCl. Since contaminating 5'-nucleotidase exhibited almost no activity under these conditions, the 5'-GMP formed could be recovered from the reaction mixture, and the yield was 805 mg from 5 g of RNA. PMID:6184020

  18. Implementation of the program of quality control of the system on-board imager of varian: initial assessment

    International Nuclear Information System (INIS)

    Ortega Martin, I.; Ruiz Morales, C.; Lopez Sanchez, F.; Tobarra Gonzalez, B. M.

    2013-01-01

    This work aims to present evidence that are part of our quality control system on-board Imager of Varian, elaborated from recommendations and national and international protocols, as well as a first assessment of the results obtained to date. (Author)

  19. Treatment-Planning Study of Prostate Cancer Intensity-Modulated Radiotherapy With a Varian Clinac Operated Without a Flattening Filter

    International Nuclear Information System (INIS)

    Vassiliev, Oleg N.; Kry, Stephen F.; Kuban, Deborah A.; Salehpour, Mohammad; Mohan, Radhe; Titt, Uwe

    2007-01-01

    Purpose: To assess the feasibility of intensity-modulated radiotherapy for prostate cancer using photon beams from an accelerator operated without a flattening filter; and to determine potential benefits and drawbacks of using unflattened beams for this type of treatment. Methods and Materials: Intensity-modulated radiotherapy plans were generated for 10 patients with early-stage prostate cancer. For each patient, four plans were generated: with and without the flattening filter, at 6 and 18 MV. The prescription dose was 75.6 Gy to 98% of the planning target volume. The number of beams, their orientations, and optimization constraints were the same for all plans. Plans were generated with Eclipse 8.0 (Varian Medical Systems). Results: All the plans developed with unflattened beams were clinically acceptable. In terms of patient dose distributions, plans with unflattened beams were similar to the corresponding plans with flattened beams. Plans with unflattened beams required fewer monitor units (MUs) per plan: on average, by a factor of 2.0 at 6 MV and 2.6 at 18 MV, assuming that removal of the flattening filter was not followed by recalibration of MUs. Conclusions: Clinically acceptable intensity-modulated radiotherapy plans for prostate cancer can be developed with unflattened beams at both 6 and 18 MV. Dosimetrically, flattened and unflattened beams generated similar treatment plans. The plans with unflattened beams required substantially fewer MUs. The reduction in the number of MUs indicates corresponding reduction in beam-on time and in the amount of radiation outside the target

  20. SU-F-T-66: Characteristics of Electron Beams From Varian Trubeam

    International Nuclear Information System (INIS)

    Dimofte, A; Kennedy, C; Zhu, T

    2016-01-01

    Purpose: The purpose of this study was to compare the electron beam data between Truebeam and 2300ix Varian accelerators for percent depth dose for broad beam and small circular cutouts, cone factors, head scatter factor as a function of cone size and SSD, phantom scatter factor, blocking factor, distance factor and virtual source position. Methods: Measurements were performed for Truebeam and 2300ix Varian accelerators. The main energies used were: 6, 9, 12, 16 and 20 MeV. PDD was measured at SSD = 100 cm for open beam and small circular cutouts (r = 0.5, 1.0, 1.5, 2.0, 3.0, 4.0 and 6.6cm) for different energies. Measurements to determine the head scatter factor (H) were done as a function of radius for six representative energies and five cone sizes (6, 10, 15, 20 and 25cm2). The phantom scatter factor (PSF) is defined as the ratio of blocking factor in water at reference depth and head scatter factor in air. PSF was measured as a function of radius and electron energy. Distance factor was measured for all energies and cones for three SSD’s (100, 110 and 120cm). Results: The percent depth dose (PDD) was measured for small cutouts of radius r = 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0 and 5.6cm. Blocking factor (BF) was measured for Truebeam and 2300ix accelerators, for different circular cutouts and energies for a 10×10 cone. Cone factors were compared between the two accelerators for different energies and applicator sizes. Conclusion: Cone factors measured for the two accelerator types differ by up to 5% for the largest applicator size. Blocking factors differs by up to 3%, with the largest variation for the smallest field size (0.5cm). Distance factor for different SSD’s differ by up to 4.5%.

  1. The evaluation for the usability of the Varian Standard Couch modelingusing Treatment Planning System

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong Mo; Song, Yong Min; Kim, Jin Man; Choi, Ji Min; Choi, Byeung Gi [Dept. of Radiation Oncology, Samsung Medical Center, Seoul (Korea, Republic of)

    2016-06-15

    When a radiation treatment, there is an attenuation by Carbon Fiber Couch. In this study, we tried to evaluate the usability of the Varian Standard Couch(VSC) by modeling with Treatment Planning System (TPS) VSC was scanned by CBCT(Cone Beam Computed Tomography) of the Linac(Clinac IX, VARIAN, USA), following the three conditions of VSC, Side Rail OutGrid(SROG), Side Rail InGrid(SRIG), Side Rail In OutSpine Down Bar(SRIOS). After scan, the data was transferred to TPS and modeled by contouring Side Rail, Side Bar Upper, Side Bar Lower, Spine Down Bar automatically. We scanned the Cheese Phantom(Middelton, USA) using Computed Tomography(Light Speed RT 16, GE, USA) and transfer the data to TPS, and apply VSC modeled previously with TPS to it. Dose was measured at the isocenter of Ion Chamber(A1SL, Standard imaging, USA) in Cheese Phantom using 4 and 10 MV radiation for every 5° gantry angle in a different filed size(3 X 3 cm{sup 2},10 X 10cm{sup 2}) without any change of MU(=100), and then we compared the calculated dose and measured dose. Also we included dose at the 127° in SRIG to compare the attenuation by Side Bar Upper. Results : The density of VSC by CBCT in TPS was 0.9g/cm{sup 3}, and in the case of Spine Down Bar, it was 0.7g/cm{sup 3}. The radiation was attenuated by 17.49%, 16.49%, 8.54%, and 7.59% at the Side Rail, Side Bar Upper, Side Bar Lower, and Spine Down Bar. For the accuracy of modeling, calculated dose and measured dose were compared. The average error was 1.13% and the maximum error was 1.98% at the 170° beam crossing the Spine Down Bar. To evaluate the usability for the VSC modeled by TPS, the maximum error was 1.98% as a result of compassion between calculated dose and measured dose. We found out that VSC modeling helped expect the dose, so we think that it will be helpful for the more accurate treatment.

  2. Monte Carlo simulation of the Varian Clinac 600C accelerator using dynamic wedges

    International Nuclear Information System (INIS)

    Moreno, S.; Chaves, A.; Lopes, M.C.; Peralta, L.; Universidade de Lisboa

    2004-01-01

    The advent of linear accelerators (linac) with computer-controlled dynamic collimation systems and functional and anatomical imaging techniques allowed a more exact delimitation and localisation of the target volume. These advanced treatment techniques inevitably increase the complexity level of dose calculation because of the introduction of the temporal variable. On account of this, it is mandatory the usage of more accurate modelling techniques of the collimator components, as it is the case of Monte Carlo (MC) simulation, which has created an enormous interest in research and clinical practice. Because the patients bodies are not homogenous nor are their body surfaces plane and regular, the dose distribution may differ significantly from the standard distribution from the linac calibration. It is in the treatment planning systems, which include algorithms that are usually measured in homogeneous water phantoms specific for each correction that the dose distributions from each case are obtained. In a real treatment, exception made to superficial lesions, two or more radiation fields are used in order to obtain the recommended dose distributions. The simplest arrangement is made from two parallel and opposed fields that originate a homogeneous dose distribution in almost all the irradiated volume. The available resources are, for example, different types of energies and of radiation, the application of bolus, the protection of healthy structures, the usage of wedged filters and the application of dynamic wedges. A virtual or dynamic wedge, modelled through the movement of one of the jaws, when compared with a set of physical wedges offers an alternative calculation method of an arbitrary number of wedged fields, instead of the four traditional fields of 15 deg, 30 deg, 45 deg and 60 deg angle and obtained with physical wedges. The goal of this work consists in the study of the application of dynamic wedges in tailoring the radiation field by the Varian Clinac 600

  3. SU-F-T-66: Characteristics of Electron Beams From Varian Trubeam

    Energy Technology Data Exchange (ETDEWEB)

    Dimofte, A; Kennedy, C; Zhu, T [University Pennsylvania, Philadelphia, PA (United States)

    2016-06-15

    Purpose: The purpose of this study was to compare the electron beam data between Truebeam and 2300ix Varian accelerators for percent depth dose for broad beam and small circular cutouts, cone factors, head scatter factor as a function of cone size and SSD, phantom scatter factor, blocking factor, distance factor and virtual source position. Methods: Measurements were performed for Truebeam and 2300ix Varian accelerators. The main energies used were: 6, 9, 12, 16 and 20 MeV. PDD was measured at SSD = 100 cm for open beam and small circular cutouts (r = 0.5, 1.0, 1.5, 2.0, 3.0, 4.0 and 6.6cm) for different energies. Measurements to determine the head scatter factor (H) were done as a function of radius for six representative energies and five cone sizes (6, 10, 15, 20 and 25cm2). The phantom scatter factor (PSF) is defined as the ratio of blocking factor in water at reference depth and head scatter factor in air. PSF was measured as a function of radius and electron energy. Distance factor was measured for all energies and cones for three SSD’s (100, 110 and 120cm). Results: The percent depth dose (PDD) was measured for small cutouts of radius r = 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0 and 5.6cm. Blocking factor (BF) was measured for Truebeam and 2300ix accelerators, for different circular cutouts and energies for a 10×10 cone. Cone factors were compared between the two accelerators for different energies and applicator sizes. Conclusion: Cone factors measured for the two accelerator types differ by up to 5% for the largest applicator size. Blocking factors differs by up to 3%, with the largest variation for the smallest field size (0.5cm). Distance factor for different SSD’s differ by up to 4.5%.

  4. Comparative analysis of gyrotron backward-wave oscillators operating at different cyclotron harmonics

    International Nuclear Information System (INIS)

    Yeh, Y.S.; Chang, T.H.; Wu, T.S.

    2004-01-01

    A comparative analysis between the fundamental and second cyclotron harmonics of gyrotron backward-wave oscillators (gyro-BWOs) is presented. The simulation results reveal that nonlinear field contraction is a common feature for both harmonic interactions. Besides, the electron transit angle, used to characterize the axial modes of the fundamental harmonic TE 11 mode at the start-oscillation conditions, is found to be applicable even for the second harmonic TE 21 mode. Each axial mode of either the fundamental harmonic TE 11 or the second harmonic TE 21 modes is maintained at a constant value of the electron transit angle while changing the operating parameters, such as magnetic field and beam voltage. Extensive numerical calculations are conducted for the start-oscillation currents and tuning properties. Moreover, single-mode operating regimes are suggested where the second harmonic TE 21 gyro-BWO could generate a considerable output power, comparing with the fundamental harmonic TE 11 gyro-BWO

  5. Analysis of Mig-type electron guns for a 35GHz gyrotron

    International Nuclear Information System (INIS)

    Barroso, J.J.; Galvao, G.P.

    1988-05-01

    A 35GHz gyrotron is currently under construction at the Associated Plasma Laboratory of the Institute for Space Research to be used in plasma heating and noninductive current drive experiments. A critical component of the device is the electrooptical system, which must generate a beam with low velocity spread and high transverse energy. One way to decrease the velocity spread is to use laminar beams. For laminar flow, where the trajectories do not cross, the axial component of the space-charge forces changes sign each half cycle models of magnetron injection guns that produce laminar beams are analyzed and procedures for controlling the pitch angle parameter, which defines the transverse-to-axial electron velocity ratio are investigated. (author)

  6. Nonstationary oscillation of gyrotron backward wave oscillators with cylindrical interaction structure

    International Nuclear Information System (INIS)

    Chen, Shih-Hung; Chen, Liu

    2013-01-01

    The nonstationary oscillation of the gyrotron backward wave oscillator (gyro-BWO) with cylindrical interaction structure was studied utilizing both steady-state analyses and time-dependent simulations. Comparisons of the numerical results reveal that the gyro-BWO becomes nonstationary when the trailing field structure completely forms due to the dephasing energetic electrons. The backward propagation of radiated waves with a lower resonant frequency from the trailing field structure interferes with the main internal feedback loop, thereby inducing the nonstationary oscillation of the gyro-BWO. The nonstationary gyro-BWO exhibits the same spectral pattern of modulated oscillations with a constant frequency separation between the central frequency and sidebands throughout the whole system. The frequency separation is found to be scaled with the square root of the maximum field amplitude, thus further demonstrating that the nonstationary oscillation of the gyro-BWO is associated with the beam-wave resonance detuning

  7. Studies of self-consistent field structure in a quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Antonsen, T.M. Jr.

    1993-04-01

    The presence of an electron beam in a quasi-optical gyrotron cavity alters the structure of the fields from that of the empty cavity. A computer code has been written which calculates this alteration for either an electron beam or a thin dielectric tube placed in the cavity. Experiments measuring the quality factor of such a cavity performed for the case of a dielectric tube and the results agree with the predictions of the code. Simulations of the case of an electron beam indicate that self-consistent effects can be made small in that almost all the power leaves the cavity in a symmetric gaussian-like mode provided the resonator parameters are chosen carefully. (author) 6 figs., 1 tab., 13 refs

  8. Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz.

    Science.gov (United States)

    Yoon, Dongyoung; Soundararajan, Murari; Cuanillon, Philippe; Braunmueller, Falk; Alberti, Stefano; Ansermet, Jean-Philippe

    2016-01-01

    An increase in Dynamic Nuclear Polarization (DNP) signal intensity is obtained with a tunable gyrotron producing frequency modulation around 260GHz at power levels less than 1W. The sweep rate of frequency modulation can reach 14kHz, and its amplitude is fixed at 50MHz. In water/glycerol glassy ice doped with 40mM TEMPOL, the relative increase in the DNP enhancement was obtained as a function of frequency-sweep rate for several temperatures. A 68 % increase was obtained at 15K, thus giving a DNP enhancement of about 80. By employing λ/4 and λ/8 polarizer mirrors, we transformed the polarization of the microwave beam from linear to circular, and achieved an increase in the enhancement by a factor of about 66% for a given power. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Magnetron injection gun for a broadband gyrotron backward-wave oscillator

    International Nuclear Information System (INIS)

    Yuan, C. P.; Chang, T. H.; Chen, N. C.; Yeh, Y. S.

    2009-01-01

    The magnetron injection gun is capable of generating relativistic electron beam with high velocity ratio and low velocity spread for a gyrotron backward-wave oscillator (gyro-BWO). However, the velocity ratio (α) varies drastically against both the magnetic field and the beam voltage, which significantly limits the tuning bandwidth of a gyro-BWO. This study remedies this drawback by adding a variable trim field to adjust the magnetic compression ratio when changing the operating conditions. Theoretical results obtained by employing a two-dimensional electron gun code (EGUN) demonstrate a constant velocity ratio of 1.5 with a low axial velocity spread of 6% from 3.4-4.8 Tesla. These results are compared with a three-dimensional particle-tracing code (computer simulation technology, CST). The underlying physics for constant α will be discussed in depth.

  10. Magnetron injection gun for a broadband gyrotron backward-wave oscillator

    Science.gov (United States)

    Yuan, C. P.; Chang, T. H.; Chen, N. C.; Yeh, Y. S.

    2009-07-01

    The magnetron injection gun is capable of generating relativistic electron beam with high velocity ratio and low velocity spread for a gyrotron backward-wave oscillator (gyro-BWO). However, the velocity ratio (α) varies drastically against both the magnetic field and the beam voltage, which significantly limits the tuning bandwidth of a gyro-BWO. This study remedies this drawback by adding a variable trim field to adjust the magnetic compression ratio when changing the operating conditions. Theoretical results obtained by employing a two-dimensional electron gun code (EGUN) demonstrate a constant velocity ratio of 1.5 with a low axial velocity spread of 6% from 3.4-4.8 Tesla. These results are compared with a three-dimensional particle-tracing code (computer simulation technology, CST). The underlying physics for constant α will be discussed in depth.

  11. Numerical Design of Megawatt Gyrotron with 120 GHz Frequency and 50% Efficiency for Plasma Fusion Application

    Science.gov (United States)

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

    2013-02-01

    The design of 120 GHz, 1 MW gyrotron for plasma fusion application is presented in this paper. The mode selection is carried out considering the aim of minimum mode competition, minimum cavity wall heating, etc. On the basis of the selected operating mode, the interaction cavity design and beam-wave interaction computation are carried out by using the PIC code. The design of triode type Magnetron Injection Gun (MIG) is also presented. Trajectory code EGUN, synthesis code MIGSYN and data analysis code MIGANS are used in the MIG designing. Further, the design of MIG is also validated by using the another trajectory code TRAK. The design results of beam dumping system (collector) and RF window are also presented. Depressed collector is designed to enhance the overall tube efficiency. The design study confirms >1 MW output power with tube efficiency around 50% (with collector efficiency).

  12. Design of a double-anode magnetron-injection gun for the W-band gyrotron

    Science.gov (United States)

    Jang, Kwang Ho; Choi, Jin Joo; So, Joon Ho

    2015-07-01

    A double-anode magnetron-injection gun (MIG) was designed. The MIG is for a W-band 10-kW gyrotron. Analytic equations based on adiabatic theory and angular momentum conservation were used to examine the initial design parameters such as the cathode angle, and the radius of the beam emitting surface. The MIG's performances were predicted by using an electron trajectory code, the EGUN code. The beam spread of the axial velocity, Δvz/vz, obtained from the EGUN code was observed to be 1.34% at α = 1.3. The cathode edge emission and the thermal effect were modeled. The cathode edge emission was found to have a major effect on the velocity spread. The electron beam's quality was significantly improved by affixing non-emissive cylinders to the cathode.

  13. 1 megawatt, 100 GHz gyrotron study. Final report, March 21-September 1, 1983

    International Nuclear Information System (INIS)

    Dionne, N.J.; Mallavarpu, R.; Palevsky, A.

    1983-01-01

    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

  14. Dielectric properties during electron irradiation of alternative materials for gyrotron windows

    International Nuclear Information System (INIS)

    Vila, R.; Ibarra, A.; Hodgson, E.R.

    1996-01-01

    Recent work on high power gyrotron windows has focused interest on some homopolar insulators as alternatives to sapphire due to their combined low dielectric loss and high thermal conductivity. The two main candidates at this moment, CVD diamond and high resistivity silicon, have been studied. As an indicator of their radiation behaviour, loss tangent and permittivity at about 15 GHz have been measured under 1.8 MeV electron irradiation at RT. In the case of silicon the previously observed radiation-induced decrease of loss tangent has been confirmed reaching a lower saturation level of 3.5 x 10 -5 at higher doses, and falling with increasing frequency. An even more important observation is that the sensitivity to ionizing radiation dropped by 4 orders of magnitude due to the radiation dose. First results for diamond are also promising, only a small degradation at relatively short times being seen with no further changes up to the maximum dose used. (orig.)

  15. Numerical optimization of quasi-optical mode converter for frequency step-tunable gyrotron

    International Nuclear Information System (INIS)

    Drumm, O.

    2002-08-01

    This work concentrates on the design of a quasi-optical mode converter for a frequency step-tunable gyrotron. Special attention is paid to the optimization of the conversion and forming of the exited wave of different frequencies inside the resonator. The investigations were part of the HGF-strategy-fonds-project ''Optimization of Tokamak Operation with controlled ECRH-Deposition''. In the resonator of the gyrotron modes can be exited at frequencies between 105 and 140 GHz. With the designed converter the desired field distribution at the output window for all frequencies will be approximately obtained. The newly gained knowledge and invented synthesis methods are applied to this practical example and verified. In this work, the waveguide antenna and the mirror system of the quasi-optical mode converter are presented separately from each other. At the beginning the synthesis of the aperture antenna for a frequency step-tunable design of the Vlasov-type as well as the Denisov-type is considered. As a conclusion of the investigation, the important parameters for the design of all antennas are summarized and the frequency behavior is compared. In the second part of this work new broadband design methods for the synthesis of the mirror surface are presented. These mirrors make an optimal wave forming for all frequencies equally possible. Therefore new quality criteria are introduced for the broadband evaluation of the mirror. Afterwards the surface is varied until the criteria reach an optimum. For the numerical optimization, in this work the gradient method and the extended Katsenelenbaum-Semenov algorithm are invented and applied. The efficient realization of the described algorithms on a computer is the significant point. The theoretical background of the presented methods for the synthesis of a mirror system is based on the general solution of the Helmholtz equation. Due to this, these methods can be utilized in other fields outside the microwave applications in

  16. SU-E-T-775: Use of Electronic Portal Imaging Device (EPID) for Quality Assurance (QA) of Electron Beams On Varian Truebeam System

    Energy Technology Data Exchange (ETDEWEB)

    Cai, B; Yaddanapudi, S; Sun, B; Li, H; Noel, C; Mutic, S; Goddu, S [Department of Radiation Oncology, Washington University in St Louis, St. Louis, MO (United States)

    2015-06-15

    Purpose: In a previous study we have demonstrated the feasibility of using EPID to QA electron beam parameters on a single Varian TrueBeam LINAC. This study aims to provide further investigation on (1) reproducibility of using EPID to detect electron beam energy changes on multiple machines and (2) evaluation of appropriate calibration methods to compare results from different EPIDs. Methods: Ad-hoc mode electron beam images were acquired in developer mode with XML code. Electron beam data were collected on a total of six machines from four institutions. A custom-designed double-wedge phantom was placed on the EPID detector. Two calibration methods - Pixel Sensitivity Map (PSM) and Large Source-to-Imager Distance Flood Field (LSID-FF) - were used. To test the sensitivity of EPID in detecting energy drifts, Bending Magnet Current (BMC) was detuned to invoke energy changes corresponding to ∼±1.5 mm change in R50% of PDD on two machines from two institutions. Percent depth ionization (PDI) curves were then analyzed and compared with the respective baseline images using LSID-FF calibration. For reproducibility testing, open field EPID images and images with a standard testing phantom were collected on multiple machines. Images with and without PSM correction for same energies on different machines were overlaid and compared. Results: Two pixel shifts were observed in PDI curve when energy changes exceeded the TG142 tolerance. PSM showed the potential to correct the differences in pixel response of different imagers. With PSM correction, the histogram of images differences obtained from different machines showed narrower distributions than those images without PSM correction. Conclusion: EPID is sensitive for electron energy changes and the results are reproducible on different machines. When overlaying images from different machines, PSM showed the ability to partially eliminate the intrinsic variation of various imagers. Research Funding from Varian Medical Systems

  17. A reviewed technique for total body electron therapy using a Varian Clinac 2100C/D high dose rate treatment beam facility

    International Nuclear Information System (INIS)

    Oliver, L.D.; Xuereb, E.M.A.; Last, V.; Hunt, P.B.; Wilfert, A.

    1996-01-01

    Our (Royal North Shore Hospital) most recent linear accelerator acquisition is a Varian Clinac 2100C/D which has a high dose rate (approximately 25Gy per minute at 1 metre) total body electron option. We investigated the physical characteristics of the electron beam to develop a suitable method of treatment for total body electron therapy. The useful electron beam width is defined as 80cm above and below the reference height. Measurements of the electron dose received from the two angled electron beams showed a critical dependence on the gantry angles. The treatment protocol uses ten different patient angles, fractionated into directly opposing fields and treated seuqentially each day. A full cycle of treatment is completed in five days. (author)

  18. Neutron contamination of Varian Clinac iX 10 MV photon beam using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Yani, S; Haryanto, F; Arif, I; Tursinah, R; Rhani, M F; Soh, R C X

    2016-01-01

    High energy medical accelerators are commonly used in radiotherapy to increase the effectiveness of treatments. As we know neutrons can be emitted from a medical accelerator if there is an incident of X-ray that hits any of its materials. This issue becomes a point of view of many researchers. The neutron contamination has caused many problems such as image resolution and radiation protection for patients and radio oncologists. This study concerns the simulation of neutron contamination emitted from Varian Clinac iX 10 MV using Monte Carlo code system. As neutron production process is very complex, Monte Carlo simulation with MCNPX code system was carried out to study this contamination. The design of this medical accelerator was modelled based on the actual materials and geometry. The maximum energy of photons and neutron in the scoring plane was 10.5 and 2.239 MeV, respectively. The number and energy of the particles produced depend on the depth and distance from beam axis. From these results, it is pointed out that the neutron produced by linac 10 MV photon beam in a typical treatment is not negligible. (paper)

  19. An EPID-based method for comprehensive verification of gantry, EPID and the MLC carriage positional accuracy in Varian linacs during arc treatments

    International Nuclear Information System (INIS)

    Rowshanfarzad, Pejman; McGarry, Conor K; Barnes, Michael P; Sabet, Mahsheed; Ebert, Martin A

    2014-01-01

    In modern radiotherapy, it is crucial to monitor the performance of all linac components including gantry, collimation system and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method has been introduced in conjunction with an algorithm to investigate the stability of these systems during arc treatments with the aim of ensuring the accuracy of linac mechanical performance. The Varian EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in MLC carriages as a result of linac rotation were separately investigated by acquisition of EPID images of a simple phantom comprised of 5 ball-bearings during arc delivery. A fast and robust software package was developed for automated analysis of image data. Twelve Varian linacs of different models were investigated. The average EPID sag was within 1 mm for all tested linacs. All machines showed less than 1 mm gantry sag. Changes in SDD values were within 1.7 mm except for three linacs of one centre which were within 9 mm. Values of EPID skewness and tilt were negligible in all tested linacs. The maximum sag in MLC leaf bank assemblies was around 1 mm. The EPID sag showed a considerable improvement in TrueBeam linacs. The methodology and software developed in this study provide a simple tool for effective investigation of the behaviour of linac components with gantry rotation. It is reproducible and accurate and can be easily performed as a routine test in clinics

  20. Quasi-optical converters for high-power gyrotrons: a brief review of physical models, numerical methods and computer codes

    International Nuclear Information System (INIS)

    Sabchevski, S; Zhelyazkov, I; Benova, E; Atanassov, V; Dankov, P; Thumm, M; Arnold, A; Jin, J; Rzesnicki, T

    2006-01-01

    Quasi-optical (QO) mode converters are used to transform electromagnetic waves of complex structure and polarization generated in gyrotron cavities into a linearly polarized, Gaussian-like beam suitable for transmission. The efficiency of this conversion as well as the maintenance of low level of diffraction losses are crucial for the implementation of powerful gyrotrons as radiation sources for electron-cyclotron-resonance heating of fusion plasmas. The use of adequate physical models, efficient numerical schemes and up-to-date computer codes may provide the high accuracy necessary for the design and analysis of these devices. In this review, we briefly sketch the most commonly used QO converters, the mathematical base they have been treated on and the basic features of the numerical schemes used. Further on, we discuss the applicability of several commercially available and free software packages, their advantages and drawbacks, for solving QO related problems

  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. Particle-in-cell analysis of beam-wave interaction in gyrotron cavity with tapered magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A., E-mail: anil.gyrotron@gmail.com [Gyrotron Lab., Microwave Tube Area, Central Electronics Engineering Research Inst. (CEERI, CSIR), Pilani, Rajasthan (India); Banasthali Univ., Dept. of Physics, Banasthali, Rajasthan (India); Khatun, H.; Kumar, N.; Singh, U.; Sinha, A.K. [Gyrotron Lab., Microwave Tube Area, Central Electronics Engineering Research Inst. (CEERI, CSIR), Pilani, Rajasthan (India); Vyas, V. [Banasthali Univ., Dept. of Physics, Banasthali, Rajasthan (India)

    2010-11-15

    A commercially available electromagnetic simulator -- MAGIC, a particle-in-cell (PIC) code -- has been used to carry out a comparative study of the beam-wave interaction under uniform and tapered magnetic field profiles of a 42 GHz, 200kW gyrotron. The magnetic field profile across the resonant cavity varies by ±6.5% with a peak value of 1.615 T. The MAGIC simulation shows the desire performance of the gyrotron under both magnetic field conditions with an operating mode TE{sub 03} and a pitch factor of 1.26. The analysis of the simulated results show that stability in the power growth was reached more quickly and achieved higher output power in the case of a tapered magnetic field. (author)

  3. Design and simulation of a {approx}390 GHz seventh harmonic gyrotron using a large orbit electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Li Fengping; He Wenlong; Cross, Adrian W; Donaldson, Craig R; Zhang Liang; Phelps, Alan D R; Ronald, Kevin, E-mail: Fengping.li@strath.ac.u [SUPA, Department of Physics, University of Strathclyde, Glasgow, G4 0NG (United Kingdom)

    2010-04-21

    A {approx}390 GHz harmonic gyrotron based on a cusp electron gun has been designed and numerically modelled. The gyrotron operates at the seventh harmonic of the electron cyclotron frequency with the beam interacting with a TE{sub 71} waveguide mode. Theoretical as well as numerical simulation results using the 3D particle-in-cell code MAGIC are presented. The cusp gun generated an axis-encircling, annular shaped electron beam of energy 40 keV, current 1.5 A with a velocity ratio {alpha} of 3. Smooth cylindrical waveguides have been studied as the interaction cavities and their cavity Q optimized for 390 GHz operation. In the simulations {approx}600 W of output power at the design frequency has been demonstrated.

  4. 30 kV/10 mA solid state anode modulator for gyrotron plasma heating: design issues and results

    International Nuclear Information System (INIS)

    Fasel, D.; Lucia, C.; Ganuza, D.; Doyharzabal, I.

    2001-01-01

    Three 30 kV/10 mA solid state pulsed modulators have been delivered to the CRPP in Lausanne, by the company JEMA. Each modulator supplies the anode grid of a triode type gyrotron, used for heating purpose at the third harmonic in the TCV Tokamak. The main parameters of the final design are: the use of solid state technology, a floating output referred to the -80 kV of the gyrotron cathode potential, an output voltage range of -5 to 30 kV, 1 kHz square and sinusoidal modulation, fast switching off to -5 kV (10 μs) and pulsed operation (duty cycle of 1%). After studying and testing a solution based on regulated Mosfet transistors in series, a more stable alternative has been adopted. The final topology consists of a rectifier fed from an insulated 230 V input, a chopper, two inverter steps (for +30 and -5 kV) supplying two diode rectifiers bridges through HV transformers with two switches which commute the load to the positive or negative voltage, connected in series. This article presents the most significant aspects of the design, with special emphasis on the control principle. The final results will be presented in the context of normal operation, supplying a triode gyrotron

  5. Parasitic oscillation in and suppression of a gyro BW mode in a low-Q 8 GHz gyrotron

    International Nuclear Information System (INIS)

    Muggli, P.; Tran, M.Q.; Tran, T.M.

    1991-12-01

    The parasitic oscillation of the TE o 21 gyrotron Backward Wave (gyro BW) mode is observed in a low-Q, 8 GHz TE o 011 gyrotron. Although at low power (P BW o 011 mode efficiency of less than 0.25. The parasitic oscillation is suppressed by operating the gyrotron with a negative magnetic field gradient along the electron beam, which allows the maximum efficiency to reach 0.40 and the output power to be multiplied by a factor varying from 1.4 to 1.7. The optimum efficiency curve of the TE o 011 mode indicates that the low-Q cavity behaves as a much higher Q diff cavity. Too large magnetic field gradient and α values favour the TE o 012 longitudinal mode, which oscillates in place of the TE o 011 mode and limits its maximum output power. This competitive process is responsible for the high-Q like output power. (author) 14 figs., 14 refs

  6. Performance studies of varian VPM-154D.6D VPM-154A/1.6L static crossed field photomultipliers

    International Nuclear Information System (INIS)

    Lo, C.C.; Leskovar, B.

    1977-01-01

    Characteristics have been measured for the Varian VPM-154D.6D and VPM-154A/1.6L Static Crossed Field Photomultipliers. Some typical photomultiplier characteristics such as: gain, dark current, quantum efficiency, and rise-time--are compared with data provided by the manufacturer. Photomultiplier characteristics generally not available from the manufacturer, such as: transit time, FWHM of the output pulse, peak output current measurement and multiphotoelectron time resolution were measured and are discussed

  7. Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations.

    Science.gov (United States)

    Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

    2014-01-01

    High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by (241)Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy(-1) for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy(-1) achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production.

  8. Monte Carlo simulation of Varian Linac for 6 MV photon beam with BEAMnrc code

    Science.gov (United States)

    Mohammed, Maged; El Bardouni, T.; Chakir, E.; Boukhal, H.; Saeed, M.; Ahmed, Abdul-Aziz

    2018-03-01

    The purpose of this study is to investigate the effects of the initial electron beam parameters on the absorbed dose distribution calculated with EGSnrc Monte Carlo code, for 6 MV photon beam. A proposed methodology for benchmarking the BEAMnrc model of Varian Linac has been used. Also, a new photon cross section data based on ENDF/B-VII release 8 evaluation has been employed. The parameters tested include mean energy, radial intensity distribution and angular spread of the initial electron beam. Mean energy and angular spread were tested for a square irradiation field 10 × 10 cm2, whereas beam width of the electron beam was studied for 10 × 10 cm2 at different depths and 30 × 30 cm2 at depth of 10 cm. The results obtained are compared with measurement data to select the optimal electron beam parameters. The differences between MC calculation and measurements data are analyzed using gamma index criteria which fixed within 1% -1 mm accuracy. The obtained results indicated that the depth-dose and dose-profile curves were considerably influenced by the mean energy of the electron beam. The depth-dose curves were unaffected by the beam width of the electron beam, for both irradiation fields. On the contrary, lateral dose-profile curves were affected by the beam width of initial electron beam. Both dose-profile and depth-dose curves were unaffected to the angular spread of the electron beam. A deep depth of 10 × 10 cm2 is very accurate to tune the beam width. Mean energy and beam width must be tuned precisely, to get the MC does distribution with acceptable accuracy.

  9. Assessment of dosimetrical performance in 11 Varian a-Si500 electronic portal imaging devices

    International Nuclear Information System (INIS)

    Kavuma, Awusi; Glegg, Martin; Currie, Garry; Elliott, Alex

    2008-01-01

    Dosimetrical characteristics of 11 Varian a-Si-500 electronic portal imaging devices (EPIDs) in clinical use for periods ranging between 10 and 86 months were investigated for consistency of performance and portal dosimetry implications. Properties studied include short-term reproducibility, signal linearity with monitor units, response to reference beam, signal uniformity across the detector panel, signal dependence on field size, dose-rate influence, memory effects and image profiles as a function of monitor units. The EPID measurements were also compared with those of the ionization chambers' to ensure stability of the linear accelerators. Depending on their clinical installation date, the EPIDs were interfaced with one of the two different acquisition control software packages, IAS2/IDU-II or IAS3/IDU-20. Both the EPID age and image acquisition system influenced the dosimetric characteristics with the newer version (IAS3 with IDU-20) giving better data reproducibility and linearity fit than the older version (IAS2 with IDU-II). The relative signal response (uniformity) after 50 MU was better than 95% of the central value and independent of detector. Sensitivity for all EPIDs reduced continuously with increasing dose rates for the newer image acquisition software. In the dose-rate range 100-600 MU min -1 , the maximum variation in sensitivity ranged between 1 and 1.8% for different EPIDs. For memory effects, the increase in the measured signal at the centre of the irradiated field for successive images was within 1.8% and 1.0% for the older and newer acquisition systems, respectively. Image profiles acquired at a lower MU in the radial plane (gun-target) had gradients in measured pixel values of up to 25% for the older system. Detectors with software/hardware versions IAS3/IDU-20 have a high degree of accuracy and are more suitable for routine quantitative IMRT dosimetrical verification.

  10. Monte Carlo simulation of the Varian Clinac 600C accelerator dynamic and physical wedges

    Energy Technology Data Exchange (ETDEWEB)

    Soares, S [Universidade da Beira Interior, Av. Marques d' Avila e Bolama, Covilha 6201-001 (Portugal); Chaves, A [Instituto Portugues de Oncologia Doutor Francisco Gentil (IPO), Av. Bissaya Barreto, Coimbra 3000-075 (Portugal); Peralta, L [Laboratorio de Instrumentacao e Fisica Experimental de PartIculas (LIP), Av. Elias Garcia no14 1o, Lisbon 1000-149 (Portugal); Lopes, Mc [Faculdade de Ciencias da Universidade de Lisboa, Campo Grande EdifIcio C5, Lisbon 1149-016 (Portugal)

    2007-06-15

    The present paper describes the study done on the dosimetric characteristics of the Varian Clinac 600C dynamic wedges (DW) and their comparison with the physical wedges (PW) in terms of the differences affecting the dose distributions, beam spectra, energy fluence and angular distributions. The geometry of the 4 MV photon beam and the dose distributions in a water phantom were simulated with GEANT3 and DPM Monte Carlo code systems. The DW was modelled through the constant movement of the upper jaws. The depth dose distributions and lateral profiles for the DW, PW and open fields were measured and compared with the Monte Carlo simulations and the global agreement was found to be within 3%. It was also found that the effects of a DW on beam spectral and angular distributions are much less significant than those produced by a PW. For example, in our study we found out that the 45{sup 0}PW, when compared with the corresponding open field, can introduce a 30% increase in the mean photon energy due to the beam hardening effect and that it can also introduce a 4.5% dose reduction in the build-up region because of the reduction of the contaminated electrons by the PW. For the DW neither this mean-energy increase nor such dose reduction was found. The PW, when compared to the DW, significantly alters the photon-beam spectrum and these dosimetric differences are significant and further investigation must be performed to quantify the impact in clinical use of these beams.

  11. Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform)

    International Nuclear Information System (INIS)

    Sorcini, B.; Tilikidis, A.

    2006-01-01

    Image-guided radiation therapy (IGRT) can be used to measure and correct positional errors for target and critical structures immediately prior to or during treatment delivery. Some of the most recent available methods applied for target localization are: trans-abdominal ultrasound, implanted markers with in room MV or kV X-rays, optical surface tracking systems, implantable electromagnetic markers, in room CT such as kVCT on rail, kilo-voltage or mega-voltage cone-beam CT (CBCT) and helical megavoltage CT. The verification of the accurate treatment position in conjunction with detailed anatomical information before every fraction can be essential for the outcome of the treatment. In this paper we present the on-board imager (OBI, Varian Medical Systems, Palo Alto, CA) that has been in routine clinical use at the Karolinska University Hospital since June 2004. The OBI has been used for on-line set-up correction of prostate patients using internal gold markers. Displacements of these markers can be monitored radiographically during the treatment course and the registered marker shifts act as a surrogate for prostate motion. For this purpose, on-board kV-kV seems to be an ideal system in terms of image quality. The CBCT function of OBI was installed in March 2005 at our department. It focuses on localizing tumors based on internal anatomy, not just on the conventional external marks or tattoos. The CBCT system provides the capacity for soft tissue imaging in the treatment position and real-time radiographic monitoring during treatment delivery. (authors)

  12. PENJADWALAN JOBS PADA SINGLE MACHINE DENGAN MEMINIMUMKAN VARIANS WAKTU PENYELESAIAN JOBS Studi Kasus di P.T. XYZ

    Directory of Open Access Journals (Sweden)

    I Nyoman Sutapa

    2001-01-01

    Full Text Available This paper discusses a jobs scheduling on a single machine to minimize variance of job completion time. The objective is especially important in situations where it is desirable to provide customers or jobs with approximately the same treatment. In this case, data are collected from P.T. 'XYZ'. The focus of discussion is LB/KB Departement (Leather Board/Carton Board with carton board's production line, which produces carton board. Carton board's size is 150 x 110 cm and its thickness from 0,6 mm to 2,5 mm. In this paper a comparison analysis, the deviation of the objective value given by a heuristic (Vh method from the objective value given by P.T. 'XYZ' (Vp, is made. The percentage of deviation Vh from Vp is 50,36 %, which shows that the performance of heuristic is better, that is variance of job completion time by heuristic method smaller than by P.T. 'XYZ'. Besides the above discussion, the weakness dan superiority of heuristic are analyzed too. Abstract in Bahasa Indonesia : Makalah ini membahas penjadwalan jobs pada single machine dengan tujuan meminimumkan varians waktu penyelesaian job, yaitu untuk memberikan konsumen atau jobs kurang lebih perlakuan yang sama. Data yang diambil dalam pembahasan ini berasal dari perusahaan P.T. 'XYZ', di mana departemen yang menjadi fokus pembahasan adalah Departemen LB/KB (Leather Board/Karton Board dengan lintasan produksi karton board yang menghasilkan produk carton board ukuran 150 x 110 cm, dengan ketebalan 0,6 mm sampai dengan 2,5 mm. Dalam makalah ini dilakukan analisis perbandingan jadwal jobs pada proses produksi di perusahaan yang telah ada dengan jadwal jobs menggunakan metode heuristic, yaitu menggunakan persentase penyimpangan Vh (varians waktu penyelesaian jobs metode heuristic dari Vp (varians waktu penyelesaian jobs perusahaan. Dari hasil analisis didapatkan bahwa persentase penyimpangan Vh dari Vp sebesar 50,36%, hal ini menunjukkan bahwa performance metode heuristic lebih baik, yaitu

  13. Towards the optimization of the thermal–hydraulic performance of gyrotron collectors

    Energy Technology Data Exchange (ETDEWEB)

    Savoldi, Laura; Bertani, Cristina [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy); Cau, Francesca; Cismondi, Fabio [F4E, Barcelona (Spain); Gantenbein, Gerd; Illy, Stefan [Karlsruhe Institute of Technology (KIT), Institute for Pulsed Power and Microwave Technology (IHM), Kaiserstr. 12, 76131 Karlsruhe (Germany); Monni, Grazia [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy); Rozier, Yoann [Thales Electron Devices, 78141 Vélizy-Villacoublay (France); Zanino, Roberto, E-mail: roberto.zanino@polito.it [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy)

    2015-11-15

    Different configurations of water-cooled Cu collector for gyrotrons are investigated using the StarCCM + CFD code, aimed at optimizing its thermal–hydraulic (TH) performance. Although the current collectors show a good performance, the collector can be subjected to transient heat loads, due to the spent electron beam, of up to several tens of MW/m{sup 2}, and there is an interest to increase the gyrotron output power in the future. Furthermore, an optimized cooling will lead to improved reliability and lifetime of the collector. Starting from a hypervapotron (HV)-like collector, characterized by 100+ deep rectangular cavities with aspect ratio (AR) = 3, we present in the first part of the paper a single-cavity steady-state parametric analysis of the effect of AR on the heat exhaust capabilities. The investigation is then extended to other collector designs, including circumferential ribs and dimples, in order to assess the options for further improvements of the TH performance. The peak Cu temperature is computed by the code and its minimization is the target of the present optimization exercise. A self-consistent estimate of the heat transfer coefficient between collector and coolant is also obtained, which could be useful for fatigue and lifetime assessments. In the second part of the paper the most promising collector geometries identified in the first part are analyzed in the case of a transient heat load (vertical sweeping), first at the level of a single spatial period of the collector structure, then at the full-collector level. The results of the TH transient analysis are compared with both the results of the first part and with the transient purely thermal analysis of the full collector, showing for all geometries considered in this study a room for cooling efficiency improvement with respect to the HV-like design with AR = 3, at least in the operating conditions considered for this study (V ∼ 4 m/s, almost 100 °C sub-cooling).

  14. Numerical investigation of collector cooling for a 1 MW ITER gyrotron operated with vertical sweeping

    Energy Technology Data Exchange (ETDEWEB)

    Savoldi, Laura; Bertani, Cristina [Dipartimento Energia, Politecnico di Torino (Italy); Cau, Francesca; Cismondi, Fabio [Fusion for Energy, Barcelona (Spain); Gantenbein, Gerd; Illy, Stefan [KIT, Karlsruhe (Germany); Monni, Grazia [Dipartimento Energia, Politecnico di Torino (Italy); Zanino, Roberto, E-mail: roberto.zanino@polito.it [Dipartimento Energia, Politecnico di Torino (Italy)

    2015-11-15

    The present gyrotron designs for EC plasma heating in nuclear fusion reactors require the safe exhaust of a power comparable to that injected into the plasma, in order to keep the maximum temperature below the acceptable value of 300 °C. In this paper, the commercial computational fluid dynamics (CFD) software STAR-CCM+{sup ®} is used to analyze the thermal performance of the annular copper collector of a 1 MW ITER gyrotron, equipped with a hypervapotron structure made of annular fins with rectangular cavities of aspect ratio (depth/width) = 3, cooled by highly subcooled (90–100 °C) pressurized water flowing at ∼4 m/s. It is assumed that the simple vertical sweeping strategy is used to reduce the very high peak heat flux on the collector (up to 30 MW/m{sup 2} transient, 5 MW/m{sup 2} time average), due to the spent electron beam. The 2D steady-state conjugate heat transfer problem is solved assuming azimuthal symmetry and accounting for 2-phase flow. The single-cavity flow and heat transfer problem is considered first, to optimize the mesh and the selection of the turbulence model. For the operating conditions considered in this paper, the full collector (100+ cavities) solution shows that boiling occurs only in a limited number of cavities close to the peaks of the heat flux, with the vapor remaining trapped in the bottom of the cavities, i.e. no full hypervapotron regime should be achieved in these operating conditions. The steady-state analysis allows the numerical evaluation of the heat transfer coefficients between Cu and water; these are then used as input for the simplified, purely thermal (solid only) analysis of the actual transient problem for the full collector. The results of the simplified model, which allows a huge reduction of the computational effort, are successfully benchmarked against those of a comprehensive thermal–hydraulic simulation. The computed peak Cu temperature is below the acceptable limit under the steady-state (time averaged

  15. SU-F-BRE-11: Neutron Measurements Around the Varian TrueBeam Linac

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, R; Seuntjens, J; Kildea, J [McGill University, Montreal, QC (Canada); Liang, L; DeBlois, F [Jewish General Hospital, Montreal, QC (Canada); Evans, M [Montreal General Hospital, Montreal, QC (Canada); Licea, A [Canadian Nuclear Safety Comission, Ottawa, Ontario (Canada); Dubeau, J; Witharana, S [Detec, Gatineau, QC (Canada)

    2014-06-15

    Purpose: With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spectrometer (NNS, Detec). The neutron spectrum, total fluence and source strength were measured and compared for 10 MV with and without flattening filter and the effect of moderation by the room and maze was studied for the 15 MV beam. Methods: The NNS, similar to traditional Bonner sphere detectors but operated in current mode, was used to measure the neutron fluence and spectrum. The NNS was validated for use in high dose rate environments using Monte Carlo simulations and calibrated at NIST and NRC Canada. Measurements were performed at several positions within the treatment room and maze with the linac jaws closed to maximize neutron production. Results: The measurements showed a total fluence reduction between 35-40% in the room and maze when the flattening filter was removed. The neutron source strength Qn was calculated from in-room fluence measurements and was found to be 0.042 × 10{sup 2} n/Gy, 0.026 × 10{sup 2} n/Gy and 0.59 × 101{sup 2} n/Gy for the 10 MV, the 10 MV FFF and 15 MV beams, respectively. We measured ambient equivalent doses of 11 mSv/hr, 7 mSv/hr and 218 mSv/hr for the 10 MV, 10 MV FFF and 15 MV by the head. Conclusion: Our measurements revealed a decrease in total fluence, neutron source strength and equivalent dose of approximately 35-40% across the treatment room for the FFF compared to FF modes. This demonstrates, as expected, that the flattening filter is a major component of the neutron production for the TrueBeam. The authors greatly acknowledge support form the Canadian Nuclear Commission and the Natural Sciences and Engineering Research Council of Canada through the CREATE program. Co

  16. A high-voltage equipment (high voltage supply, high voltage pulse generators, resonant charging inductance, synchro-instruments for gyrotron frequency measurements) for plasma applications

    International Nuclear Information System (INIS)

    Spassov, Velin

    1996-01-01

    This document reports my activities as visitor-professor at the Gyrotron Project - INPE Plasma Laboratory. The main objective of my activities was designing, construction and testing a suitable high-voltage pulse generator for plasma applications, and efforts were concentrated on the following points: Design of high-voltage resonant power supply with tunable output (0 - 50 kV) for line-type high voltage pulse generator; design of line-type pulse generator (4 microseconds pulse duration, 0 - 25 kV tunable voltage) for non linear loads such as a gyrotron and P III reactor; design of resonant charging inductance for resonant line-type pulse generator, and design of high resolution synchro instrument for gyrotron frequency measurement. (author)

  17. 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.

  18. Design of 95 GHz gyrotron based on continuous operation copper solenoid with water cooling

    International Nuclear Information System (INIS)

    Borodin, Dmitri; Ben-Moshe, Roey; Einat, Moshe

    2014-01-01

    The design work for 2nd harmonic 95 GHz, 50 kW gyrotron based on continuous operation copper solenoid is presented. Thermionic magnetron injection gun specifications were calculated according to the linear trade off equation, and simulated with CST program. Numerical code is used for cavity design using the non-uniform string equation as well as particle motion in the “cold” cavity field. The mode TE02 with low Ohmic losses in the cavity walls was chosen as the operating mode. The Solenoid is designed to induce magnetic field of 1.8 T over a length of 40 mm in the interaction region with homogeneity of ±0.34%. The solenoid has six concentric cylindrical segments (and two correction segments) of copper foil windings separated by water channels for cooling. The predicted temperature in continuous operation is below 93 °C. The parameters of the design together with simulation results of the electromagnetic cavity field, magnetic field, electron trajectories, and thermal analyses are presented

  19. Design of 95 GHz gyrotron based on continuous operation copper solenoid with water cooling

    Energy Technology Data Exchange (ETDEWEB)

    Borodin, Dmitri; Ben-Moshe, Roey; Einat, Moshe [Department of Electrical and Electronic Engineering, Ariel University, Ariel 40700 (Israel)

    2014-07-15

    The design work for 2nd harmonic 95 GHz, 50 kW gyrotron based on continuous operation copper solenoid is presented. Thermionic magnetron injection gun specifications were calculated according to the linear trade off equation, and simulated with CST program. Numerical code is used for cavity design using the non-uniform string equation as well as particle motion in the “cold” cavity field. The mode TE02 with low Ohmic losses in the cavity walls was chosen as the operating mode. The Solenoid is designed to induce magnetic field of 1.8 T over a length of 40 mm in the interaction region with homogeneity of ±0.34%. The solenoid has six concentric cylindrical segments (and two correction segments) of copper foil windings separated by water channels for cooling. The predicted temperature in continuous operation is below 93 °C. The parameters of the design together with simulation results of the electromagnetic cavity field, magnetic field, electron trajectories, and thermal analyses are presented.

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

    International Nuclear Information System (INIS)

    Yeh, Y. S.; Chen, C. H.; Yang, S. J.; Lai, C. H.; Lin, T. Y.; Lo, Y. C.; Hong, J. W.; Hung, C. L.; Chang, T. H.

    2012-01-01

    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 11 drive wave, the second harmonic component of the beam current initiates a TE 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%.

  1. Recovering traditional raw-milk Tetilla cheese flavour and sensory attributes by using Kocuria varians and Yarrowia lipolytica adjunct cultures.

    Science.gov (United States)

    Centeno, J A; Garabal, J I; Docampo, F; Lorenzo, J M; Carballo, J

    2017-06-19

    The rationale of the present study was to evaluate the potential of microbial adjunct cultures including Kocuria varians and/or Yarrowia lipolytica strains in the recovery of the typical sensory profile of traditional (raw-milk) Tetilla cheese. Four batches of Tetilla cheese, a short ripened cows' milk cheese produced in Galicia (NW Spain), were made in duplicate from pasteurized milk inoculated with different microbial cultures. A control batch was manufactured by adding a mesophilic commercial D-starter only. The other three batches were made with the same starter after a cheese-milk pre-ripening step carried out with (i) an adjunct culture of K. varians, (ii) an adjunct culture of Y. lipolytica, or (iii) a combination of both adjunct cultures. The highest pH and water activity values, associated with softer textures were determined in the cheeses manufactured with the Y. lipolytica adjunct after 21days of ripening. The contents of the volatile compounds 3-methylbutanol, dimethyl disulfide and dimethyl trisulfide were higher in the cheeses made with only the K. varians adjunct than in the cheeses made with the only yeast adjunct and in the control cheeses. The contents of hexanoic and octanoic acids were highest in the cheeses made with the Y. lipolytica adjunct, and levels of ethyl hexanoate, ethyl octanoate and ethyl decanoate were higher in the cheeses made with only the yeast adjunct than in the other batches of cheese. The cheeses manufactured with both adjunct cultures were awarded the highest scores for flavour and overall sensory parameters (considering the standards of the traditional product) and were considered very similar to 'good quality' artisanal raw-milk cheeses. We conclude that use of selected Micrococcaceae and Y. lipolytica strains as adjunct cultures would differentiate the sensory properties and contribute to the quality and typicality of the short-ripened rennet-curd Galician Tetilla and Arzúa-Ulloa cheeses. Copyright © 2017 Elsevier B

  2. Out‐of‐field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators

    Science.gov (United States)

    Cardenas, Carlos E.; Nitsch, Paige L.; Kudchadker, Rajat J.; Howell, Rebecca M.

    2016-01-01

    Out‐of‐field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high‐energy electron beams. To better understand the extent of these exposures, we measured out‐of‐field dose characteristics of electron applicators for high‐energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out‐of‐field dose profiles and percent depth‐dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out‐of‐field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out‐of‐field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central‐axis, which was found to be higher than typical out‐of‐field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for

  3. Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

    Science.gov (United States)

    Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

    2016-07-08

    Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases.

  4. SU-E-T-06: A Comparison of IMRT Treatment of Esophageal Carcinoma in Elekta-Precise and Varian23EX Linac

    Energy Technology Data Exchange (ETDEWEB)

    Bai, W; Fan, X; Qiu, R; Qiao, X; Zhang, R [Hebei Medical University Fourth Hospital, Shijiazhuang, Hebei (China)

    2014-06-01

    Purpose: To compare and analyze the characteristics of static intensity-modulated radiotherapy (IMRT) plans designed on Elekta and Varian Linac in different esophageal cancer(EC), exploring advantages and disadvantages of different vendor Linac, thus can be better serve for clinical. Methods: Twenty-four patients with EC were selected, including 6 cases located in the cervical, upper, middle and the lower thorax, respectively. Two IMRT plans were generated with the Oncentra planning system: in Elekta and Varian Linac, prescription dose of 60Gy in 30 fractions to the PTV. We examined the dose-volume histogram parameters of PTV and the organs at risk (OAR) such as lungs, spinal cord and heart, and additional Monitor units(MU), treatment time, Homogeneity index(HI), Conformity index(CI) and Gamma index comparisons were performed. Results: All plans resulted in abundant dose coverage of PTV for EC of different locations. The doses to PTV, HI and OAR in Elekta plans were not statistically different in comparison with Varian plans, with the following exceptions: in cervical, upper and lower thoracic EC the PTV's CI, and in middle thorax EC PTV's D2, D50, V105 and PTV-average were better in Elekta plans than in Varian plans. In the cervical, upper and the middle thorax EC, treatment time were significantly decreased in Varian plans as against Elekta plans, while in the lower thoracic EC treatment time were no striking difference. MUs and gamma index were similar between the two Linac plans. Conclusion: For the the middle thorax EC Varian plans is better than Elekta plans, not only in treatment time but in the PTV dose; while for the lower thorax EC Elekta plans is the first choice for better CI; for the other part of the EC usually Elekta plans can increase the CI, while Varian plans can reduce treatment time, can be selected according to the actual situation of the patient treatment.

  5. Interactions between Lactobacillus sakei and CNC (Staphylococcus xylosus and Kocuria varians) and their influence on proteolytic activity.

    Science.gov (United States)

    Tremonte, P; Reale, A; Di Renzo, T; Tipaldi, L; Di Luccia, A; Coppola, R; Sorrentino, E; Succi, M

    2010-11-01

    To evaluate interactions between Lactobacillus sakei and coagulase negative cocci (CNC) (Staphylococcus xylosus and Kocuria varians) and to investigate the influence of these interactions on their own proteolytic activity. Interactions occurring between strains of Lact. sakei and CNC were assessed by spectrophotometric analysis. The growth of 35 strains of Lact. sakei, used as indicators, was compared to that obtained combining the same strains with growing cells or cell-free supernatants of 20 CNC (18 Staph. xylosus and 2 K. varians). The proteolytic activity expressed by single strains or by their combinations was assessed on sarcoplasmic protein extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results evidenced that interactions are able to affect not only the growth but also the in vitro proteolytic activity of Lact. sakei and CNC used in combination. A relationship between the presence of interactions among useful strains and the strength of technological characteristics, such as proteolysis, was defined. The study highlighted that CNC are able to stimulate the growth of some Lact. sakei strains. At the same time, this interaction positively influences the proteolytic activity of strains used in combination. Given the importance of proteolysis during the ripening of fermented meats, this phenomenon should be taken into account to select meat starter cultures. © 2010 The Authors. © 2010 The Society for Applied Microbiology.

  6. Micro-pulses generation in ECR breakdown stimulated by gyrotron radiation at 37,5 GHz

    International Nuclear Information System (INIS)

    Skalyga, V.; Zorin, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Vodopyanov, A.

    2012-01-01

    The present work is devoted to experimental and theoretical investigation of the creation of short pulsed (< 100 μs) multicharged ion beams. The possibility of quasi-stationary generation of short pulsed beams under conditions of quasi-gasdynamic plasma confinement was shown in recent experiments. Later another way of such beams creation based on the Pre-glow effect was proposed. In present work it was demonstrated that in the case when duration of microwave (MW) pulse is less than formation time of Pre-glow peak, realization of a regime when ion current is negligible during MW pulse and intense multicharged ions flux appears only when MW ends could be possible. Such pulses after the end of MW were called micro-pulses. In the present work the generation of micro-pulses was observed in experiments with ECR discharge stimulated by gyrotron radiation at 37,5 GHz, 100 kW. In this case pulses with duration less than 30 μs were obtained. Probably the same effect was observed in GANIL where 14 GHz radiation was used and pulses with duration about 2 ms were registered. In present work it was shown that the intensity of such micro-pulse could be higher than intensity of Pre-glow peak at the same conditions but with longer MW pulse. The generation of micro-pulses of nitrogen and argon multicharged ions with current of a few mA and length about 30 μs after MW pulse with duration of 30-100 μs was demonstrated. The low level of impurities, high current density and rather high average charge make possible to consider such micro-pulse regime as a possibility for the creation of a short pulsed ion source. The paper is followed by the slides of the presentation. (authors)

  7. 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

    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 and the operat...

  8. Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2018-02-01

    A design of high-order mode input coupler for 220-GHz confocal gyrotron travelling wave tube is proposed, simulated, and demonstrated by experimental tests. This input coupler is designed to excite confocal TE 06 mode from rectangle waveguide TE 10 mode over a broadband frequency range. Simulation results predict that the optimized conversion loss is about 2.72 dB with a mode purity excess of 99%. Considering of the gyrotron interaction theory, an effective bandwidth of 5 GHz is obtained, in which the beam-wave coupling efficiency is higher than half of maximum. The field pattern under low power demonstrates that TE 06 mode is successfully excited in confocal waveguide at 220 GHz. Cold test results from the vector network analyzer perform good agreements with simulation results. Both simulation and experimental results illustrate that the reflection at input port S11 is sensitive to the perpendicular separation of two mirrors. It provides an engineering possibility for estimating the assembly precision.

  9. Fusion development and technology

    International Nuclear Information System (INIS)

    Montgomery, D.B.

    1992-01-01

    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

  10. CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS

    Science.gov (United States)

    Arce, Pedro; Lagares, Juan Ignacio

    2018-02-01

    We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN Clinac 2100 C/D linear accelerator by the procedure of adjusting the initial beam parameters to fit the percentage depth dose and cross-profile dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2  ×  2 cm2 to 40  ×  40 cm2, a small phantom voxel size and high statistics, fine precision in the determination of the beam parameters has been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. Standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple-scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting, a comprehensive CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.

  11. Determination of the dose equivalents due to neutrons produced during therapeutic irradiations with a Varian CLINAC 2500; Determinacion de la dosis equivalente debida a neutrones producidos durante irradiaciones terapeuticas con un Varian CLINAC 2500

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo, Ricardo E [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Yucatan (Mexico)

    1991-07-01

    This experiment it was designed to quantify that so important it is the dose equivalent deposited by the neutron flow that is generated by photonuclear reactions during therapeutic irradiations with X rays of produced high-energy for an accelerator Varian CLINAC 2500. This accelerator type is routinely used in the Department of Radiotherapy of the Hospital of the University of Wisconsin, E.U. The equivalent dose was measured in diverse towns of the room of irradiations using the activation of thin sheets of gold put in the center of plastic recipients full with water. In general, the recipients were 1 m or more than the floor and at distances still bigger than the walls. The irradiations were made using photons with the highest energy that you can select with this team - 24 MeV. The due equivalent dose to neutrons taken place here by the energy photons used they were measured and reported. (author)

  12. Research on nuclear fusion reactor - Development of mm-wve (Electron cyclotron) heating device

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sae Young; Myung, Jung Su; Lee, Keun Ho; Lee, Myung Jae; Kim, Hyung Suk; Hur, Jin Woo; Song, Ho Young [Institute for Advanced Engineering, Seoul (Korea, Republic of)

    1996-08-01

    To establish cooperating system with foreign relevant research institutes, consultation has been given to IAE by Dr. T. V. George regarding ECRH and gyrotron development plan. Discussions with Prof. Temkin and Dr. Kreisher at MIT, who are working for ITER gyrotron development, were made and those helped IAE to collect necessary information for fundamental parameters of ECCD. Also, Prof. Vic Granatstein, U. of Maryland, and Dr. Baruch Levush, NRL, were consulted for computer codes of the gyrotron R and D. It will also be prepared for cooperation in ECCD and mm-wave heating with device research teams of General Atomics and Russia. By visiting various University labs and research institutes and investigating the up-to-date research results, the basic operating parameters of gyrotron for KSTAR project has been determined. By cooperation with MIT, a conceptual design has been made for the KSTAR gyrotron that should generate 1 MW and 110 GHz CW waves. The simulation result of EGUN using self-consistent theory shows that 1.2 MW power with the efficiency of 42.8% can be obtained for TE22,6,1 mode where the average ohmic loss is 0.54 kW/cm{sup 2} assuming 77 kV cathode voltage, 34 A beam current, velocity ratio of 1.62 and perpendicular velocity spread of 6.5%. 9 refs., 5 figs., 3 tabs. (author)

  13. SU-E-T-370: Measurement of Conical Cone Output Factors for the Varian Edge Linear Accelerator

    International Nuclear Information System (INIS)

    Li, H; Kim, J; Gordon, J; Chetty, I; Wang, S; Zhong, H; Wen, N

    2014-01-01

    Purpose: To quantify the impact of detector type, SSD/depth, and intermediate reference on conical cone output factor (OF) measurements for the Varian Edge linac. Methods: OF's for 4, 5, 7.5, 10, 12.5, 15, and 17.5 mm diameter cones relative to 10cmx10cm field were measured for the 6X FFF and 10X FFF energies, with jaws set to 5cmx5cm. Measurements were performed with an Edge diode (0.8mmx0.8mmx0.03mm WxLxT), stereotatic diode SFD, photon diode, CC01 and pinpoint chambers (2mm diameter for both). 95cm SSD/5cm depth were used in a water tank. For the measurement with diodes, OF's were cross-referred to CC13 ion chamber measurements with 3cmx3cm field, as recommended, to help mitigate the energy variation in diode response with field size. Results were compared to the representative data from Varian measured with Edge detector. With SFD, OF's at 98.5cm SSD/1.5cm depth and 90cm SSD/10cm depth were also measured. Results: OF's measured with the Edge detector matched within 1.3% (max diff) with the representative data from Varian. For the SFD, OF's matched within 1.3% for the 4, 5 and 17.5 mm cones and within 3.7% for the other cones. OF's with photon diode were within 1.3% except for the 4 and 5 mm cones where they were 8.1% and 3.7%, respectively. OF's for the CC01 and pinpoint chamber deviated up to 36% and 44%, respectively for the 4 mm cone. OF's after intermediate reference with 3cmx3cm field changed by 3.7% for SFD, 0.8% for photon diode, and 0.6% for Edge detector. OF's at 98.5cm SSD/1.5cm depth were 10.8% higher than that at 95cm SSD/5cm depth, and OF's at 90cm SSD/1.5cm depth were 7.5% lower. Conclusion: OF's measured with the Edge detector appear to be reliable. CC01 and pinpoint chambers do not appear suitable for measuring the small cone OF's. SSD/depth affects OF measurements significantly

  14. SU-E-T-362: Enhanced Dynamic Wedge Output Factors for Varian 2300CD and the Case for a Reference Database

    International Nuclear Information System (INIS)

    Njeh, C

    2015-01-01

    Purpose: Dose inhomogeneity in treatment planning can be compensated using physical wedges. Enhanced dynamic wedges (EDW) were introduced by Varian to overcome some of the short comings of physical wedges. The objectives of this study were to measure EDW output factors for 6 MV and 20 MV photon energies for a Varian 2300CD. Secondly to review the literature in terms of published enhanced dynamic wedge output factors (EDWOF) for different Varian models and thereby adding credence to the case of the validity of reference databases. Methods: The enhanced dynamic wedge output factors were measured for the Varian 2300CD for both 6 MV and 20 MV photon energies. Twelve papers with published EDWOF for different Varian Linac models were found in the literature. Results: The EDWOF for 6 MV varied from 0.980 for a 5×5 cm 10 degree wedge to 0.424 for 20×20 cm 60 degree wedge. Similarly for 20 MV, the EDWOF varied from 0.986 for 5×5 cm 10 degree wedge to 0.529 for 20×20 cm 60 degree wedge. EDWOF are highly dependent on field size. Comparing our results with the published mean, we found an excellent agreement for 6 MV EDWOF with the percentage differences ranging from 0.01% to 0.57% with a mean of 0.03%. The coefficient of variation of published EDWOF ranged from 0.17% to 0.85% and 0.1% to 0.9% for the for 6 MV and 18MV photon energies respectively. This paper provides the first published EDWOF for 20 MV photon energy. In addition, we have provided the first compendium of EDWOFs for different Varian linac models. Conclusion: The consistency of EDWOF across models and institution provide further support that, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes

  15. Determination of the dose equivalents due to neutrons produced during therapeutic irradiations with a Varian CLINAC 2500

    International Nuclear Information System (INIS)

    Carrillo, Ricardo E.

    1991-01-01

    This experiment it was designed to quantify that so important it is the dose equivalent deposited by the neutron flow that is generated by photonuclear reactions during therapeutic irradiations with X rays of produced high-energy for an accelerator Varian CLINAC 2500. This accelerator type is routinely used in the Department of Radiotherapy of the Hospital of the University of Wisconsin, E.U. The equivalent dose was measured in diverse towns of the room of irradiations using the activation of thin sheets of gold put in the center of plastic recipients full with water. In general, the recipients were 1 m or more than the floor and at distances still bigger than the walls. The irradiations were made using photons with the highest energy that you can select with this team - 24 MeV. The due equivalent dose to neutrons taken place here by the energy photons used they were measured and reported. (author)

  16. Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

    Science.gov (United States)

    Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

    2016-10-01

    The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit.

  17. SU-E-T-405: Evaluation of the Raystation Electron Monte Carlo Algorithm for Varian Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Sansourekidou, P; Allen, C [Health Quest, Poughkeepsie, NY (United States)

    2015-06-15

    Purpose: To evaluate the Raystation v4.51 Electron Monte Carlo algorithm for Varian Trilogy, IX and 2100 series linear accelerators and commission for clinical use. Methods: Seventy two water and forty air scans were acquired with a water tank in the form of profiles and depth doses, as requested by vendor. Data was imported into Rayphysics beam modeling module. Energy spectrum was modeled using seven parameters. Contamination photons were modeled using five parameters. Source phase space was modeled using six parameters. Calculations were performed in clinical version 4.51 and percent depth dose curves and profiles were extracted to be compared to water tank measurements. Sensitivity tests were performed for all parameters. Grid size and particle histories were evaluated per energy for statistical uncertainty performance. Results: Model accuracy for air profiles is poor in the shoulder and penumbra region. However, model accuracy for water scans is acceptable. All energies and cones are within 2%/2mm for 90% of the points evaluated. Source phase space parameters have a cumulative effect. To achieve distributions with satisfactory smoothness level a 0.1cm grid and 3,000,000 particle histories were used for commissioning calculations. Calculation time was approximately 3 hours per energy. Conclusion: Raystation electron Monte Carlo is acceptable for clinical use for the Varian accelerators listed. Results are inferior to Elekta Electron Monte Carlo modeling. Known issues were reported to Raysearch and will be resolved in upcoming releases. Auto-modeling is limited to open cone depth dose curves and needs expansion.

  18. Investigation on heat transfer analysis and its effect on a multi-mode, beam-wave interaction for a 140 GHz, MW-class gyrotron

    Science.gov (United States)

    Liu, Qiao; Liu, Yinghui; Chen, Zhaowei; Niu, Xinjian; Li, Hongfu; Xu, Jianhua

    2018-04-01

    The interaction cavity of a 140 GHz, 1 MW continuous wave gyrotron developed in UESTC will be loaded with a very large heat load in the inner surface during operation. In order to reduce the heat, the axial wedge grooves of the outside surface of the cavity are considered and employed as the heat radiation structure. Thermoanalysis and structural analysis were discussed in detail to obtain the effects of heat on the cavity. In thermoanalysis, the external coolant-flow rates ranging from 20 L/min to 50 L/min were considered, and the distribution of wall loading was loaded as the heat flux source. In structural analysis, the cavity's deformation caused by the loads of heat and pressure was calculated. Compared with a non-deformed cavity, the effects of deformation on the performance of a cavity were discussed. For a cold-cavity, the results show that the quality factor would be reduced by 72, 89, 99 and 171 at the flow rates of 50 L/min, 40 L/min, 30 L/min and 20 L/min, respectively. Correspondingly, the cold-cavity frequencies would be decreased by 0.13 GHz, 0.15 GHz, 0.19 GHz and 0.38 GHz, respectively. For a hot-cavity, the results demonstrate that the output port frequencies would be dropped down, but the offset would be gradually decreased with increasing coolant-flow rate. Meanwhile, the output powers would be reduced dramatically with decreasing coolant-flow rate. In addition, when the coolant-flow rate reaches 40 L/min, the output power and the frequency are just reduced by 30 kW and 0.151 GHz, respectively.

  19. EU Developments of the ITER ECRH System

    International Nuclear Information System (INIS)

    Henderson, M.

    2006-01-01

    The electron cyclotron (EC) heating and current drive (H (and) CD) system of ITER will deliver 20 MW/CW in the plasma at 170 GHz for H (and) CD in addition to 2.5 MW/3 s at 120 GHz for plasma start-up. The EC system is composed of power supplies (PS), up to 24 H (and) CD gyrotrons (1 to 2 MW tubes), 3 start-up gyrotrons (1 MW tubes), 24 transmission lines and two sets of launching antennas: equatorial (EL) and upper (UL) launchers. Under the present ITER procurement package the EU is responsible for one third of the H (and) CD 170 GHz gyrotrons, all PSs associated with the H (and) CD system, and the whole set (4) of upper launchers. In all areas of participation, the EU EC partnership (coordinated by the European Fusion Development Association - EFDA) aims toward advancing the technology of each of these subsystems. For example, procurement of Pulse Step Modulator (PSM) HVPS is under consideration, which might have equivalent costs to the present ITER design (thyristor HVPS and HV series switch), but with an increased flexibility in operation and variation in the EC power waveform. The EU is at the forefront in gyrotron research and is developing a 2 MW CW 170 GHz coaxial cavity gyrotron offering an increase in output power while maintaining moderate power densities in the gyrotron cavity and collector. THALES R in collaboration with its EFDA partners (FZK, CRPP, TEKES) is manufacturing a series of prototype tubes in three phases of typically 1 s, 100 s and then CW pulse capacity (∼ 20 10 ). A 2 MW, CW gyrotron test facility is being built at CRPP that will be used to develop the 2 MW coaxial tube, in addition to testing various components required by the EC system. EFDA has undertaken a parallel development of two launcher options: front (FS) and remote (RS) steering, with the aim of providing an optimum launcher for ITER weighing EC physics aspects and operation reliability. The FS launcher (ITER reference design) offers a significant enhancement in physics

  20. Female sex pheromone and male behavioral responses of the bombycid moth Trilocha varians: comparison with those of the domesticated silkmoth Bombyx mori

    Science.gov (United States)

    Daimon, Takaaki; Fujii, Takeshi; Yago, Masaya; Hsu, Yu-Feng; Nakajima, Yumiko; Fujii, Tsuguru; Katsuma, Susumu; Ishikawa, Yukio; Shimada, Toru

    2012-03-01

    Analysis of female sex pheromone components and subsequent field trap experiments demonstrated that the bombycid moth Trilocha varians uses a mixture of ( E, Z)-10,12-hexadecadienal (bombykal) and ( E,Z)-10,12-hexadecadienyl acetate (bombykyl acetate) as a sex pheromone. Both of these components are derivatives of ( E,Z)-10,12-hexadecadienol (bombykol), the sex pheromone of the domesticated silkmoth Bombyx mori. This finding prompted us to compare the antennal and behavioral responses of T. varians and B. mori to bombykol, bombykal, and bombykyl acetate in detail. The antennae of T. varians males responded to bombykal and bombykyl acetate but not to bombykol, and males were attracted only when lures contained both bombykal and bombykyl acetate. In contrast, the antennae of B. mori males responded to all the three components. Behavioral analysis showed that B. mori males responded to neither bombykal nor bombykyl acetate. Meanwhile, the wing fluttering response of B. mori males to bombykol was strongly inhibited by bombykal and bombykyl acetate, thereby indicating that bombykal and bombykyl acetate act as behavioral antagonists for B. mori males. T. varians would serve as a reference species for B. mori in future investigations into the molecular mechanisms underlying the evolution of sex pheromone communication systems in bombycid moths.

  1. Enhancement of oscillation characteristics of a gyrotron by a built-in quasi-optical mode converter

    International Nuclear Information System (INIS)

    Hayashi, Kenichi; Mitsunaka, Yoshika; Komuro, Mitsuo

    1994-01-01

    Oscillation characteristics are analyzed experimentally and numerically by using two gyrotrons with a power level of 500 kW, a conventional tube and a tube with a built-in quasi-optical mode converter. Both tubes have a 120 GHz, TE 12,2 cavity of the same geometry and a single disk alumina window. The quasi-optical mode converter consists of an α-cut launcher and five mirrors. In the conventional tube, reflection of the competing mode at the output window prevents the main mode from oscillating stably in the operation region predicted by the design. Mode selectivity of the quasi-optical mode converter removes the influence of the reflection on the oscillation. Consequently, the experimental results in the tube with the quasi-optical mode converter are in good agreement with the design values. (author)

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

    International Nuclear Information System (INIS)

    Hogge, J.P.

    1993-12-01

    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

  3. Surface dose characterisation of the Varian Ir-192 HDR conical surface applicator set with a vertically orientated source

    Energy Technology Data Exchange (ETDEWEB)

    Buchauer, Konrad; Henke, Guido; Schiefer, Hans; Plasswilm, Ludwig [Kantonsspital St. Gallen, Department of Radiation Oncology, St. Gallen (Switzerland)

    2014-12-15

    Conical surface applicators with an Ir-192 high-dose-rate brachytherapy source are a common modality for the treatment of non-melanomatous skin cancer with high tumour control rates. Surface dose characterisation of the Varian Varisource GammaMed+ IX afterloader vertical type surface applicators is performed two dimensionally using high-resolution film dosimetry. The focus of this study was to determine if Varian surface applicators with a vertical source suffer from the dose distribution irregularities reported for comparable applicators. Our goal was to evaluate if the irregularities found affected treatment and dose output verification procedures. Ionisation chamber-based verification of applicator output was established according to guidelines provided by the manufacturer. For additional measurement of surface dose Gafchromic EBT3 film dosimetry was used. The term ''therapeutic dose'' was defined as 85 % of the prescribed dose level. For the 10 different applicator inserts evaluated, cold spots were observed. Mean cold spot size was 2.0 mm x 3.6 mm (± 0.6 mm). The cold spots were dosimetrically well below 85 % of the prescribed dose. The cold spot was situated 2.2 mm (1.4-2.7 mm) unilaterally from the central axis and caused general asymmetry in the dose profiles intersecting the cold spot area. A source tilt of approximately 8 (± 1 ) was determined for the source used for irradiation. A central underdosed area exceeding 15 % of the prescribed dose has not been previously reported. Source tilt was observed and found to affect clinical use and possibly treatment outcome in applicators using a vertically arranged source. Surface applicators with a vertically orientated source were subject to dose irregularities that could impact on chamber-based applicator output verification procedures. We recommend film dosimetry-backed applicator commissioning to avoid systematic errors. (orig.) [German] Konische Oberflaechenapplikatoren sind ein

  4. Development program for a 200 kW, CW, 28 GHz gyroklystron. Final report, April 1976-September 1980

    International Nuclear Information System (INIS)

    Shively, J.; Conner, C.; Evans, S.

    1980-01-01

    The objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW, CW power output at 28 GHz. The use of the gyrotron or cyclotron resonance interaction was pursued. A room temperature hollow core solenoid magnet with an iron case was designed to produce the magnetic field required for electron cyclotron resonance. Three pulsed gyroklystron amplifiers were built providing increasing stable output powers of 6, 65 and 76 kW. A back-up pulsed gyrotron oscillator produced 248 kW. A ceramic cone broadband water load was developed. Tests are described for the various tubes that were developed

  5. Technical Report: Reference photon dosimetry data for Varian accelerators based on IROC-Houston site visit data

    Energy Technology Data Exchange (ETDEWEB)

    Kerns, James R.; Followill, David S.; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Imaging and Radiation Oncology Core-Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Graduate School of Biomedical Sciences, The University of Texas Health Science Center-Houston, Houston, Texas 77030 (United States); Lowenstein, Jessica; Molineu, Andrea; Alvarez, Paola; Taylor, Paige A. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Imaging and Radiation Oncology Core-Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Stingo, Francesco C. [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2016-05-15

    Purpose: Accurate data regarding linear accelerator (Linac) radiation characteristics are important for treatment planning system modeling as well as regular quality assurance of the machine. The Imaging and Radiation Oncology Core-Houston (IROC-H) has measured the dosimetric characteristics of numerous machines through their on-site dosimetry review protocols. Photon data are presented and can be used as a secondary check of acquired values, as a means to verify commissioning a new machine, or in preparation for an IROC-H site visit. Methods: Photon data from IROC-H on-site reviews from 2000 to 2014 were compiled and analyzed. Specifically, data from approximately 500 Varian machines were analyzed. Each dataset consisted of point measurements of several dosimetric parameters at various locations in a water phantom to assess the percentage depth dose, jaw output factors, multileaf collimator small field output factors, off-axis factors, and wedge factors. The data were analyzed by energy and parameter, with similarly performing machine models being assimilated into classes. Common statistical metrics are presented for each machine class. Measurement data were compared against other reference data where applicable. Results: Distributions of the parameter data were shown to be robust and derive from a student’s t distribution. Based on statistical and clinical criteria, all machine models were able to be classified into two or three classes for each energy, except for 6 MV for which there were eight classes. Quantitative analysis of the measurements for 6, 10, 15, and 18 MV photon beams is presented for each parameter; supplementary material has also been made available which contains further statistical information. Conclusions: IROC-H has collected numerous data on Varian Linacs and the results of photon measurements from the past 15 years are presented. The data can be used as a comparison check of a physicist’s acquired values. Acquired values that are well

  6. Technical Report: Reference photon dosimetry data for Varian accelerators based on IROC-Houston site visit data

    International Nuclear Information System (INIS)

    Kerns, James R.; Followill, David S.; Kry, Stephen F.; Lowenstein, Jessica; Molineu, Andrea; Alvarez, Paola; Taylor, Paige A.; Stingo, Francesco C.

    2016-01-01

    Purpose: Accurate data regarding linear accelerator (Linac) radiation characteristics are important for treatment planning system modeling as well as regular quality assurance of the machine. The Imaging and Radiation Oncology Core-Houston (IROC-H) has measured the dosimetric characteristics of numerous machines through their on-site dosimetry review protocols. Photon data are presented and can be used as a secondary check of acquired values, as a means to verify commissioning a new machine, or in preparation for an IROC-H site visit. Methods: Photon data from IROC-H on-site reviews from 2000 to 2014 were compiled and analyzed. Specifically, data from approximately 500 Varian machines were analyzed. Each dataset consisted of point measurements of several dosimetric parameters at various locations in a water phantom to assess the percentage depth dose, jaw output factors, multileaf collimator small field output factors, off-axis factors, and wedge factors. The data were analyzed by energy and parameter, with similarly performing machine models being assimilated into classes. Common statistical metrics are presented for each machine class. Measurement data were compared against other reference data where applicable. Results: Distributions of the parameter data were shown to be robust and derive from a student’s t distribution. Based on statistical and clinical criteria, all machine models were able to be classified into two or three classes for each energy, except for 6 MV for which there were eight classes. Quantitative analysis of the measurements for 6, 10, 15, and 18 MV photon beams is presented for each parameter; supplementary material has also been made available which contains further statistical information. Conclusions: IROC-H has collected numerous data on Varian Linacs and the results of photon measurements from the past 15 years are presented. The data can be used as a comparison check of a physicist’s acquired values. Acquired values that are well

  7. Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

    International Nuclear Information System (INIS)

    Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

    2016-01-01

    The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit. - Highlights: • A 3/6 MeV electron accelerator equipped with a high energy x-ray target was studied. • Monte Carlo modeling of photon flux was carried out for three accelerator configurations. • Human biological equivalent doses were evaluated within the accelerator facility building.

  8. Monte Carlo simulation of a varian 21EX Clinac 6 MV photon beam characteristics using GATE6

    Energy Technology Data Exchange (ETDEWEB)

    An, Jung Su [Korea Atomic Energy Research Institute, Nonproliferation System Research Division, Daejeon (Korea, Republic of); Lee, Chang Lae [Center for Radiological Environment and Health Science, Busan (Korea, Republic of); Baek, Cheol Ha [Dept. of Radiological Science, College of Health Science, Yonsei University, Seoul (Korea, Republic of)

    2016-12-15

    Monte Carlo simulations are widely used as the most accurate technique for dose calculation in radiation therapy. In this paper, the GATE6(Geant4 Application for Tomographic Emission ver.6) code was employed to calculate the dosimetric performance of the photon beams from a linear accelerator(LINAC). The treatment head of a Varian 21EX Clinac was modeled including the major geometric structures within the beam path such as a target, a primary collimator, a flattening filter, a ion chamber, and jaws. The 6 MV photon spectra were characterized in a standard 10 x 10 cm{sup 2} field at 100 cm source-to-surface distance(SSD) and subsequent dose estimations were made in a water phantom. The measurements of percentage depth dose and dose profiles were performed with 3D water phantom and the simulated data was compared to measured reference data. The simulated results agreed very well with the measured data. It has been found that the GATE6 code is an effective tool for dose optimization in radiotherapy applications.

  9. Modelling of a linear accelerator VARIAN 600 C/D for dosimetric study using the Monte Carlo Method; Modelamento de um acelerador linear VARIAN 600 C/D para estudo dosimétrico usando o Método de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Cancino, Jorge Luis Batista

    2016-07-01

    Based on the high availability of low energy linear accelerators in Brazil and with the goal of developing a reliable tool for dose distribution calculations in radiotherapy; this research aims to validate a linear accelerator head model using MCNP Monte Carlo code. The Varian 600 C/D linear accelerator installed at the Hospital São João de is taken as reference. The main components of the linear accelerator head were simulated based on detailed information of the manufacturer. In order to calculate dose distribution, a water phantom with dimensions of 30 x 30 x 30 cm{sup 3} was simulated and placed at 100 cm of source-surface distance. A monoenergetic electron beam of 6,3 MeV was considered as a source. The number of primary particles used in the simulation was 10{sup 8}. A Phase-Space Surface was used to scoring the photon spectrum below the tungsten target. Others two were placed in the model in order to reduce computational time and improve statistical accuracy. In order to validate the developed model, the X-ray spectrum generated by Bremsstrahlung was calculated and analyzed. Furthermore, the results of percentage depth doses and beam profiles calculations were compared with available measurements. The MCNP calculations results were compared to measurement showing good agreement between them. The comparison between MCNP calculations and measurement of PDD showed reasonable coherence at build-up region. The results were in an acceptable interval of confidence at the flat region of beam profiles comparison for three different field sizes. In this work, we compared MCNP calculations to experimental data in order to validate the developed LINAC head model. The results showed a good agreement according to the recommended criteria. The developed model was validated as an accurate tool for LINAC quality control procedures. (author)

  10. Orthogonal image pairs coupled with OSMS for noncoplanar beam angle, intracranial, single-isocenter, SRS treatments with multiple targets on the Varian Edge radiosurgery system

    Directory of Open Access Journals (Sweden)

    Jasmine A. Oliver, PhD

    2017-07-01

    Conclusion: Based on our study, CR-induced shifts with the Varian Edge radiosurgery system will not produce noticeable dosimetric effects for SRS treatments. Thus, replacing cone beam CT with orthogonal kV/kV pairs coupled with OSMS at the treatment couch angle could reduce the number of cone beam CT scans that are acquired during a standard SRS treatment while providing an accurate and safe treatment with negligible dosimetric effects on the treatment plan.

  11. SU-F-T-526: A Comparative Study On Gating Efficiency of Varian RPM Device and Calypso System

    Energy Technology Data Exchange (ETDEWEB)

    Ravindran, P [Christian Medical College Hospital, Vellore (India); Wui Ann, W; Lim, Y [The Brunei Cancer Center (Brunei Darussalam)

    2016-06-15

    Purpose: In general, the linear accelerator is gated using respiratory signal obtained by way of external sensors to account for the breathing motion during radiotherapy. One of the commonly used gating devices is the Varian RPM device. Calypso system that uses electromagnetic tracking of implanted or surface transponders could also be used for gating. The aim of this study is to compare the gating efficiency of RPM device and the calypso system by phantom studies. Methods: An ArcCheck insert was used as the phantom with a Gafchromic film placed in its holder. The ArcCheck insert was placed on a Motion Sim platform and moved in the longitudinal direction simulating a respiratory motion with a period of 5 seconds and amplitude of ±6mm. The Gafchromic film was exposed to a 2 × 2cm{sup 2} field, i) with the phantom static, ii) phantom moving but ungated iii) gated with gating window of 2mm and 3mm. This was repeated with Calypso system using surface transponders with the same gating window. The Gafchromic films were read with an EPSON 11000 flatbed scanner and analysed with ‘Medphysto’ software. Results: The full width at half maximum (FWHM) as measured with film at the level of the film holder was 1.65cm when the phantom was static. FWHM measured with phantom moving and without gating was 1.16 cm and penumbra was 7 mm (80–20%) on both sides. When the beam was gated with 2 mm gating window the FWHM was 1.8 cm with RPM device and 1.9 cm with Calypso. Similarly, when the beam was gated with 3 mm window, the FWHM was 1.9cm with RPM device and 2cm with Calypso. Conclusion: This work suggests that the gating efficiency of RPM device is better than that of the Calypso with surface transponder, with reference to the latency in gating.

  12. SU-F-BRE-10: Methods to Simulate and Measure the Attenuation for Modeling a Couch Top with Rails for FFF Treatment Delivery On the Varian Edge Linac

    International Nuclear Information System (INIS)

    Gulam, M; Gardner, S; Zhao, B; Snyder, K; Song, K; Li, H; Gordon, J; Wen, N; Chetty, I; Kearns, W

    2014-01-01

    Purpose: To measure attenuation for modelling of the KVue Couchtop for 6X and 10X FFF SRS/SBRT treatment Methods: Treatment planning simulation studies were done using 6X FFF beams to estimate the dosimetric impact of KVue couchtops (including the Q-Fix IGRT [carbon fiber] and Calypso [nonconductive Kevlar material]) with a structure model obtained from a research workstation (Eclipse, advanced planning interface (API) v13). Prior to installation on the Varian Edge linac, the couchtop along with (Kevlar) rails were CT scanned with the rails at various positions. An additional scan with the couchtop 15cm above the CT table top was obtained with 20cm solid water to facilitate precised/indexed data acquisition. Measurements for attenuation were obtained for field sizes of 2, 4 and 10 cm 2 at 42 gantry angles including 6 pairs of opposing fields and other angles for oblique delivery where the beams traversed the couchtop and or rails. The delivery was fully automated with xml scripts running in developer mode. The results were then used to determine an accurate structure model for AAA (Eclipse v11) planning of IMRT and RapidArc delivery. Results: The planning simulation relative dose attenuation for oblique entry was not significantly different than the Exact IGRT or BrainLab iBeam couch except that the rails added 6% additional attenuation. The relative attenuation measurements for PA, PA (rails: inner position), oblique, oblique (rails: outer position), oblique (rails: inner position) were: −2.0%, −2.5%, −15.6%, −2.5%, −5.0% for 6X FFF and −1.4%, −1.5%, −12.2%, − 2.5%, −5.0% for 10X FFF with slight decrease in attenuation versus field size. A Couch structure model (with HU values) was developed. Calculation compared to measurement showed good agreement except for oblique (rails: outer position) where differences approached a magnitude of 6%. Conclusion: A model of the couch structures has been developed accounting for attenuation for FFF beams

  13. 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.

  14. Validation of Varian TrueBeam electron phase–spaces for Monte Carlo simulation of MLC-shaped fields

    International Nuclear Information System (INIS)

    Lloyd, Samantha A. M.; Gagne, Isabelle M.; Zavgorodni, Sergei; Bazalova-Carter, Magdalena

    2016-01-01

    Purpose: This work evaluates Varian’s electron phase–space sources for Monte Carlo simulation of the TrueBeam for modulated electron radiation therapy (MERT) and combined, modulated photon and electron radiation therapy (MPERT) where fields are shaped by the photon multileaf collimator (MLC) and delivered at 70 cm SSD. Methods: Monte Carlo simulations performed with EGSnrc-based BEAMnrc/DOSXYZnrc and PENELOPE-based PRIMO are compared against diode measurements for 5 × 5, 10 × 10, and 20 × 20 cm 2 MLC-shaped fields delivered with 6, 12, and 20 MeV electrons at 70 cm SSD (jaws set to 40 × 40 cm 2 ). Depth dose curves and profiles are examined. In addition, EGSnrc-based simulations of relative output as a function of MLC-field size and jaw-position are compared against ion chamber measurements for MLC-shaped fields between 3 × 3 and 25 × 25 cm 2 and jaw positions that range from the MLC-field size to 40 × 40 cm 2 . Results: Percent depth dose curves generated by BEAMnrc/DOSXYZnrc and PRIMO agree with measurement within 2%, 2 mm except for PRIMO’s 12 MeV, 20 × 20 cm 2 field where 90% of dose points agree within 2%, 2 mm. Without the distance to agreement, differences between measurement and simulation are as large as 7.3%. Characterization of simulated dose parameters such as FWHM, penumbra width and depths of 90%, 80%, 50%, and 20% dose agree within 2 mm of measurement for all fields except for the FWHM of the 6 MeV, 20 × 20 cm 2 field which falls within 2 mm distance to agreement. Differences between simulation and measurement exist in the profile shoulders and penumbra tails, in particular for 10 × 10 and 20 × 20 cm 2 fields of 20 MeV electrons, where both sets of simulated data fall short of measurement by as much as 3.5%. BEAMnrc/DOSXYZnrc simulated outputs agree with measurement within 2.3% except for 6 MeV MLC-shaped fields. Discrepancies here are as great as 5.5%. Conclusions: TrueBeam electron phase–spaces available from Varian have been

  15. Validation of Varian TrueBeam electron phase–spaces for Monte Carlo simulation of MLC-shaped fields

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, Samantha A. M. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 3P6 5C2 (Canada); Gagne, Isabelle M., E-mail: imgagne@bccancer.bc.ca; Zavgorodni, Sergei [Department of Medical Physics, BC Cancer Agency–Vancouver Island Centre, Victoria, British Columbia V8R 6V5, Canada and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2 (Canada); Bazalova-Carter, Magdalena [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2 (Canada)

    2016-06-15

    spaces available from Varian have been implemented in two distinct Monte Carlo simulation packages to produce dose distributions and outputs that largely reflect measurement. Differences exist in the profile shoulders and penumbra tails for the 20 MeV phase–space off-axis and in the outputs for the 6 MeV phase–space.

  16. SU-E-T-325: The New Evaluation Method of the VMAT Plan Delivery Using Varian DynaLog Files and Modulation Complexity Score (MCS)

    Energy Technology Data Exchange (ETDEWEB)

    Tateoka, K [Proton Treatment Center, Radiation Therapy Research Institute, Social Medical Corporation Teishinkai, Sapporo (Japan); Graduate School of Medicine, Sapporo Medical University, Sapporo, JP (Japan); Fujimomo, K; Hareyama, M [Proton Treatment Center, Radiation Therapy Research Institute, Social Medical Corporation Teishinkai, Sapporo (Japan); Saitou, Y; Nakazawa, T; Abe, T; Nakata, A; Yano, M [Graduate School of Medicine, Sapporo Medical University, Sapporo, JP (Japan)

    2014-06-01

    Purpose: The aim of the study is to evaluate the use of Varian DynaLog files to verify VMAT plans delivery and modulation complexity score (MCS) of VMAT. Methods: Delivery accuracy of machine performance was quantified by multileaf collimator (MLC) position errors, gantry angle errors and fluence delivery accuracy for volumetric modulated arc therapy (VMAT). The relationship between machine performance and plan complexity were also investigated using the modulation complexity score (MCS). Plan and Actual MLC positions, gantry angles and delivered fraction of monitor units were extracted from Varian DynaLog files. These factors were taken from the record and verify system of MLC control file. Planned and delivered beam data were compared to determine leaf position errors and gantry angle errors. Analysis was also performed on planned and actual fluence maps reconstructed from those of the DynaLog files. This analysis was performed for all treatment fractions of 5 prostate VMAT plans. The analysis of DynaLog files have been carried out by in-house programming in Visual C++. Results: The root mean square of leaf position and gantry angle errors were about 0.12 and 0.15, respectively. The Gamma of planned and actual fluence maps at 3%/3 mm criterion was about 99.21. The gamma of the leaf position errors were not directly related to plan complexity as determined by the MCS. Therefore, the gamma of the gantry angle errors were directly related to plan complexity as determined by the MCS. Conclusion: This study shows Varian dynalog files for VMAT plan can be diagnosed delivery errors not possible with phantom based quality assurance. Furthermore, the MCS of VMAT plan can evaluate delivery accuracy for patients receiving of VMAT. Machine performance was found to be directly related to plan complexity but this is not the dominant determinant of delivery accuracy.

  17. TU-F-CAMPUS-T-04: An Evaluation of Out-Of-Field Doses for Electron Beams From Modern Varian and Elekta Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, C; Nitsch, P; Kudchadker, R; Howell, R; Kry, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: Accurately determining out-of-field doses when using electron beam radiotherapy is of importance when treating pregnant patients or patients with implanted electronic devices. Scattered doses outside of the applicator field in electron beams have not been broadly investigated, especially since manufacturers have taken different approaches in applicator designs. Methods: In this study, doses outside of the applicator field were measured for electron beams produced by a 10×10 applicator on two Varian 21iXs operating at 6, 9, 12, 16, and 20 MeV, a Varian TrueBeam operating at 6, 9, 12, 16, and 20 MeV, and an Elekta Versa HD operating at 6, 9, 12 and 15 MeV. Peripheral dose profiles and percent depth doses were measured in a Wellhofer water phantom at 100 cm SSD with a Farmer ion chamber. Doses were compared to peripheral photon doses from AAPM’s Task Group #36 report. Results: Doses were highest for the highest electron energies. Doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. Substantial dose differences were observed between different accelerators; the Elekta accelerator had much higher doses than any Varian unit examined. Surprisingly, doses were often similar to, and could be much higher than, doses from photon therapy. Doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. Conclusion: The results of this study indicate that proper shielding may be very important when utilizing electron beams, particularly on a Versa HD, while treating pregnant patients or those with implanted electronic devices. Applying a water equivalent bolus of Emax(MeV)/4 thickness (cm) on the patient would reduce fetal dose drastically for all clinical energies and is a practical solution to manage the potentially high peripheral doses seen from modern electron beams. Funding from NIH Grant number: #CA180803.

  18. Design and measurement of a TE{sub 13} input converter for high order mode gyrotron travelling wave amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Liu, Guo, E-mail: liuguo@uestc.edu.cn; Shu, Guoxiang; Yan, Ran; Wang, Li; Agurgo Balfour, E.; Fu, Hao; Luo, Yong [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wang, Shafei, E-mail: rockingsandstorm@163.com [North Electronic Device Research Institution, Box 947, Beijing 100141 (China)

    2016-03-15

    A technique to launch a circular TE{sub 13} 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) TE{sub 13} 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 TE{sub 32} and TE{sub 71} modes are suppressed to allow the transmission of the dominant TE{sub 13} 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 TE{sub 32} and TE{sub 71} 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.

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

    International Nuclear Information System (INIS)

    Vernon, R.J.

    1990-08-01

    This progress report is for the fifth year of a grant from the US Department of Energy (Contract FG02-85ER52122) for the design, development, and fabrication of ECRF transmission and mode conversion systems to transport microwave power from a gyrotron, or other high power source, to a magnetically confined plasma. (This period is also the second year covered by a three-year renewal proposal submitted in June of 1988.) The development 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. 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 in this work

  20. The application in detection the position accuracy of the multi-leaf collimator of Varian linear accelerator with dynamic therapy log files

    International Nuclear Information System (INIS)

    Li Changhu; Xu Liming; Teng Jianjian; Ge Wei; Zhang Jun; Ma Guangdong

    2010-01-01

    Objective: To explorer the application in detection the position accuracy of the multileaf collimator of Varian accelerator with dynamic therapy log files. Methods: A pre-designed MLC format files named PMLC for two Varian accelerators, the dynamic treatment log files were recorded 10 times on a different date, and be converted into the MLC format files named DMLC, compared with the original plan PMLC, so we can analysis two files for each leaf position deviation. In addition, we analysis the repeatability of MLC leaves position accuracy between 10 dynalog files of two accelerators. Results: No statistically significant difference between the average position of the 10 times leaf position of the two accelerators,their were 0.29 -0.29 and 0.29 -0.30 (z = -0.77, P=0.442). About 40%, 30%, 20% and 10% of the leaf position deviation was at ≤0.2 mm, 0.3 mm, 0.5 mm and 0.4 mm, respectively. the maximum value was 0.5 mm. More than 86% of the leaf position are completely coincident between 10 dynamic treatment files of two accelerators. The rate of position deviation no more 0. 05 mm was 96. 6% and 97.3%, respectively. And the maximum value was 0.09 mm. Conclusions: Dynamic treatment log file is a splendid tool in testing the actual position of multi-leaf collimator. The multi-leaf collimator of two accelerators be detected are precise and stabilized. (authors)

  1. Trophic transfer of trace metals from the polychaete worm Nereis diversicolor to the polychaete N. virens and the decapod crustacean Palaemonetes varians

    Science.gov (United States)

    Rainbow, P.S.; Poirier, L.; Smith, B.D.; Brix, K.V.; Luoma, S.N.

    2006-01-01

    Diet is an important exposure route for the uptake of trace metals by aquatic invertebrates, with trace metal trophic transfer depending on 2 stages - assimilation and subsequent accumulation by the predator. This study investigated the trophic transfer of trace metals from the sediment-dwelling polychaete worm Nereis diversicolor from metal-rich estuarine sediments in southwestern UK to 2 predators - another polychaete N. virens (Cu, Zn, Pb, Cd, Fe) and the decapod crustacean Palaemonetes varians (Cu, Zn, Pb, Cd, Fe, Ag, As, Mn). N. virens showed net accumulation of Cu, Zn, Pb and Cd from the prey; accumulation increased with increasing prey concentration, but a coefficient of trophic transfer decreased with increasing prey concentration, probably because a higher proportion of accumulated metal in the prey is bound in less trophically available (insoluble) detoxified forms. The trace metal accumulation patterns of P. varians apparently restricted significant net accumulation of metals from the diet of N. diversicolor to just Cd. There was significant mortality of the decapods fed on the diets of metal-rich worms. Metal-rich invertebrates that have accumulated metals from the rich historical store in the sediments of particular SW England estuaries can potentially pass these metals along food chains, with accumulation and total food chain transfer depending on the metal assimilation efficiencies and accumulation patterns of the animal at each trophic level. This trophic transfer may be significant enough to have ecotoxicological effects. ?? Inter-Research 2006.

  2. Evaluation using Monte Carlo simulations, of the effect of a shielding, called external shielding, for fotoneutrons generated in linear accelerators, using the computational model of Varian accelerator 2300 C/D operating in eight rotation angles of the GA

    International Nuclear Information System (INIS)

    Silva, Hugo R.; Silva, Ademir X.; Rebello, Wilson F.; Silva, Maria G.

    2011-01-01

    This paper aims to present the results obtained by Monte Carlo simulation of the effect of shielding against neutrons, called External Shielding, to be placed on the heads of linear accelerators used in radiotherapy. For this, it was used the radiation transport code Monte Carlo N-Particle - MCNPX, in which were developed computational model of the head of the linear accelerator Varian 2300 C/D. The equipment was simulated within a bunker, operating at energies of 10, 15 and 18 MV, considering the rotation of the gantry at eight different angles ( 0 deg, 45 deg, 90 deg, 135 deg, 180 deg, 225 deg, 270 deg and 315 deg), in all cases, the equipment was modeled without and with the shielding positioned attached to the head of the accelerator on its bottom. In each of these settings, it was calculated the Ambient Dose Equivalent due to neutron H * (10)n on points situated in the region of the patient (region of interest for evaluation of undesirable neutron doses on the patient) and in the maze of radiotherapy room (region of interest for shielding the access door to the bunker). It was observed for all energies of equipment operation as well as for all angles of inclination of the gantry, a significant reduction in the values of H * (10) n when the equipment operated with the external shielding, both in the region of the patient as in the region of the maze. (author)

  3. Evaluation of IsoCal geometric calibration system for Varian linacs equipped with on-board imager and electronic portal imaging device imaging systems.

    Science.gov (United States)

    Gao, Song; Du, Weiliang; Balter, Peter; Munro, Peter; Jeung, Andrew

    2014-05-08

    The purpose of this study is to evaluate the accuracy and reproducibility of the IsoCal geometric calibration system for kilovoltage (kV) and megavoltage (MV) imagers on Varian C-series linear accelerators (linacs). IsoCal calibration starts by imaging a phantom and collimator plate using MV images with different collimator angles, as well as MV and kV images at different gantry angles. The software then identifies objects on the collimator plate and in the phantom to determine the location of the treatment isocenter and its relation to the MV and kV imager centers. It calculates offsets between the positions of the imaging panels and the treatment isocenter as a function of gantry angle and writes a correction file that can be applied to MV and kV systems to correct for those offsets in the position of the panels. We performed IsoCal calibration three times on each of five Varian C-series linacs, each time with an independent setup. We then compared the IsoCal calibrations with a simplified Winston-Lutz (WL)-based system and with a Varian cubic phantom (VC)-based system. The maximum IsoCal corrections ranged from 0.7 mm to 1.5 mm for MV and 0.9 mm to 1.8 mm for kV imagers across the five linacs. The variations in the three calibrations for each linac were less than 0.2 mm. Without IsoCal correction, the WL results showed discrepancies between the treatment isocenter and the imager center of 0.9 mm to 1.6 mm (for the MV imager) and 0.5 mm to 1.1 mm (for the kV imager); with IsoCal corrections applied, the differences were reduced to 0.2 mm to 0.6 mm (MV) and 0.3 mm to 0.6 mm (kV) across the five linacs. The VC system was not as precise as the WL system, but showed similar results, with discrepancies of less than 1.0 mm when the IsoCal corrections were applied. We conclude that IsoCal is an accurate and consistent method for calibration and periodic quality assurance of MV and kV imaging systems.

  4. Mechanical characterization of the Varian Exact-arm and R-arm support systems for eight aS500 electronic portal imaging devices

    International Nuclear Information System (INIS)

    Grattan, Mark W. D.; McGarry, Conor K.

    2010-01-01

    Purpose: The aim of this study is to compare the positioning accuracy at different gantry angles of two electronic portal imaging devices (EPIDs) support arm systems by using EPID difference images as a measure for displacement. This work presents a comparison of the mechanical performance of eight Varian aS500 (Varian Medical Systems, Palo Alto, CA) EPIDs, mounted using either the Varian Exact-arm or R-arm. Methods: The mechanical performance of the two arm systems was compared by investigating the variation in sensitivity with gantry angle, both before and after the EPID position was adjusted after gantry rotation. Positional errors were investigated by subtracting images from a reference image taken at gantry 0 deg., and the amplitude of the peaks and troughs at the field edges for longitudinal (radial) and lateral (transverse) profiles across the resulting image was related to the distance of displacement. Calibration curves based on a pixel-by-pixel shift were generated for each EPID and the Varian hand pendant accuracy was compared to the calibration data. Results: The response of the EPIDs was found to change with gantry rotation, with the largest difference at 180 deg. The Exact-arm was found to correct well for any displacement, while the R-arm tended to overcorrect following repositioning using the hand pendant. The calibration curves were consistent within each set of matched linacs, and the hand pendant accuracy was similar for both arm systems, although generally in different directions. With respect to gantry rotation effects, the mechanical performance of the Exact-arm systems was found to be much better than that of the R-arm systems. At gantry positions 90 deg., 270 deg., and 180 deg. the average misalignment in the longitudinal direction was +4.2±0.2, +1.8±1.6, and +7.4±0.5 mm for the R-arms, and +2.9±0.2, +2.1±0.8, and +4.9±0.7 mm for the Exact-arms. In the lateral direction the average positional errors were +2.1±0.4, -4.7±0.4, and -2.5

  5. Design of planning target volume margin using an active breathing control and Varian image-guided radiotherapy (IGRT) system in unresectable liver tumor

    International Nuclear Information System (INIS)

    Yue Jinbo; Yu Jinming; Liu Jing; Liu Tonghai; Yin Yong; Shi Xuetao; Song Jinlong

    2007-01-01

    Objective: To define the planning target volume(PTV) margin with an active breathing control (ABC) and the Varian image-guided radiotherapy (IGRT) system. Methods: Thirteen patients with liver cancer were treated with radiotherapy from May 2006 to September 2006. Prior to radiotherapy, all patients had undergone transarterial chemoembolization (TACE) by infusing a mixture of iodized oil contrast medium and chemotherapeutic agents, kV fluoroscopy was used to measure the potential motion of lipiodol spot positions during ABC breath-holds. ABC was used for planning CT scan and radiation delivery, with the breath held at the same phase of the respiratory cycle (near end-exhalation). Cone beam CT (CBCT) was taken using Varian IGRT system, which was then compared online with planning CT using a 3 D-3 D matching tool. Analysis relied on lipiodol spots on planning CT and CBCT manually. The treatment table was moved to produce acceptable setup before treatment delivery. Repeated CBCT image and another analysis were obtained after irradiation. Results: No motion of the intrahepatic tumor was observed on fluoroscopy during ABC breath-holds. The estimated required PTV margins, calculated according to the Stroom formula, were 4.4 mm, 5.3 mm and 7.8 mm in the x, y and z axis directions before radiotherapy. The corresponding parameters were 2.5m, 2.6 mm and 3.9 mm after radiotherapy. Conclusions: We have adopted a PTV margin of 5 mm, 6 mm and 8 mm in the x, y and z axis directions with ABC, and 3,3 and 4 mm with ABC and on-line kilovoltage CBCT. (authors)

  6. SU-F-J-14: Kilovoltage Cone-Beam CT Dose Estimation of Varian On-Board Imager Using GMctdospp Monte Carlo Framework

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S; Rangaraj, D [Baylor Scott & White Health, Temple, TX (United States)

    2016-06-15

    Purpose: Although cone-beam CT (CBCT) imaging became popular in radiation oncology, its imaging dose estimation is still challenging. The goal of this study is to assess the kilovoltage CBCT doses using GMctdospp - an EGSnrc based Monte Carlo (MC) framework. Methods: Two Varian OBI x-ray tube models were implemented in the GMctpdospp framework of EGSnrc MC System. The x-ray spectrum of 125 kVp CBCT beam was acquired from an EGSnrc/BEAMnrc simulation and validated with IPEM report 78. Then, the spectrum was utilized as an input spectrum in GMctdospp dose calculations. Both full and half bowtie pre-filters of the OBI system were created by using egs-prism module. The x-ray tube MC models were verified by comparing calculated dosimetric profiles (lateral and depth) to ion chamber measurements for a static x-ray beam irradiation to a cuboid water phantom. An abdominal CBCT imaging doses was simulated in GMctdospp framework using a 5-year-old anthropomorphic phantom. The organ doses and effective dose (ED) from the framework were assessed and compared to the MOSFET measurements and convolution/superposition dose calculations. Results: The lateral and depth dose profiles in the water cuboid phantom were well matched within 6% except a few areas - left shoulder of the half bowtie lateral profile and surface of water phantom. The organ doses and ED from the MC framework were found to be closer to MOSFET measurements and CS calculations within 2 cGy and 5 mSv respectively. Conclusion: This study implemented and validated the Varian OBI x-ray tube models in the GMctdospp MC framework using a cuboid water phantom and CBCT imaging doses were also evaluated in a 5-year-old anthropomorphic phantom. In future study, various CBCT imaging protocols will be implemented and validated and consequently patient CT images will be used to estimate the CBCT imaging doses in patients.

  7. Research of the Electron Cyclotron Emission with Vortex Property excited by high power high frequency Gyrotron

    Science.gov (United States)

    Goto, Yuki; Kubo, Shin; Tsujimura, Tohru; Takubo, Hidenori

    2017-10-01

    Recently, it has been shown that the radiation from a single electron in cyclotron motion has vortex property. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally cancelled out due to the randomness in gyro-phase of electrons and the development of detection of the vortex property has not been well motivated. In this research, we are developing a method to generate the vortex radiation from electrons in cyclotron motion with controlled gyro-phase. Electron that rotates around the uniform static magnetic field is accelerated by right-hand circular polarized (RHCP) radiation resonantly when the cyclotron frequency coincides with the applied RHCP radiation frequency. A large number of electrons can be coherently accelerated in gyro-phase by a RHCP high power radiation so that these electrons can radiate coherent emission with vortex feature. We will show that vortex radiation created by purely rotating electrons for the first time.

  8. Development of two series ingnitron based crowbar protection system for 42 GHz and 82.6 GHz gyroton in SST-1

    International Nuclear Information System (INIS)

    Dhorajiya, Pragnesh; Dalakoti, Shefali; Patel, Harshida; Ingle, Krunal; Patel, Jatin; Sathyanarayana, K.; Rajanbabu; Shukla, B.K.

    2013-01-01

    Gyrotrons are used to generate the high power at microwave frequency that is used to heat the plasma inside a Tokamak. A conventional high voltage power supply is used for the testing of 82.6 GHz, 200 kW/CW and 42 GHz, 500 kW/500ms gyrotrons at our institute. Its maximum operating cathode parameters are -55 kV DC, 20 A. Like any other High RF power tubes gyrotrons need to be protected against arc faults within the tube. If the energy dumped in such arc fault is more than the critical crater energy of the tube, irreparable damage can occur inside the RF tube or microwave tube and rendering it useless. The specified maximum fault energy for the 42 GHz and 82.6 GHz gyrotrons is 10 joules. When conventional HVDC power supplies feed high power RF tubes or microwave tubes, a reliable crowbar protection is required which is tested separately to limit the energy to the tube in case of any type of fault to assure the tube safety. Two series ignitron (NL-37248) based crowbar system developed in-house is used to limit the arc fault energy under the acceptance level by diverting the fault current from the load or Gyrotron. Fault current diversion and interruption are initiated by the sensing element and protection system. The required protection cards are designed and developed in-house and required performance is achieved. With this crowbar system the high voltage switch-off to the gyrotron is achieved within 5 μsec after occurrence of critical faults. The crowbar is tested for voltage hold-off up to 80 kV DC. This paper presents the critical requirement of the time delay for the fault sensing and crowbar trigger generation and necessary protections that are incorporated with the ignitron switch crowbar like over voltage, pulsed over current and continuous over current. The crowbar system developed in-house, tested at rated value. The results obtained during the stand-alone tests and commissioning tests are also mentioned. Using this crowbar system the high voltage power

  9. Research on Gyrotrons.

    Science.gov (United States)

    1985-04-15

    8217 ) (2N’n I roBo )2wL(I - I/vo)exptEo2(aw/w) 2/2j { 2(kp , /mor4) 2("-1t[ 0 2L~o2 ( A/,’w)/2 - n ](2 TQV) ’, (1) C mw)m, = [n + (n2 + 42 .,4)i2 I/ 2 2...Acknowledgement The author would like to express his gratitude to his advisor , Professor Jay L. Hirshfield, for the indefatigable scientific discussion which

  10. SU-E-T-403: Evaluation of the Beam Performance of a Varian TrueBeam Linear Accelerator Under External Device-Based Gated Delivery Conditions

    International Nuclear Information System (INIS)

    Kobulnicky, K; Pawlak, D; Purwar, A

    2015-01-01

    Purpose: To examine the beam performance of a Varian TrueBeam linear accelerator under external device-based gated delivery conditions. Methods: Six gating cycles were used to evaluate the gating performance of a standard production TrueBeam system that was not specially tuned in any way. The system was equipped with a factory installed external gating interface (EXGI). An in-house EXGI tester box was used to simulate the input gating signals. The gating cycles were selected based on long beam-on and short beam-off times, short beam-on and long beam-off times, or equal beam on and off times to check linac performance. The beam latencies were measured as the time difference between the logic high gating signal and the first or last target pulses with an oscilloscope. Tissue-Phantom Ratio, beam flatness, and dose distributions from 5 different plans were measured using the 6 different gating durations and the un-gated irradiation. A PTW 729 2-D array was used to compare 5 plans versus the un-gated delivery with a 1%/1mm gamma index passing criteria. Results: The beam latencies of the linac were based off of 20 samples for beam-on and beam-off, for each gating cycle. The average beam-on delays were measured to be between 57 and 66msec, with a maximum of 88 msec. The beam off latencies averaged between 19 and 26msec, with a maximum of 48 msec. TPR20,10 measurements showed beam energy stability within 0.5% of the un-gated delivery. Beam flatness was better than 2.5% for all gated cycles. All but two deliveries, the open field with 4 seconds on, 1 second off, and a five field IMRT plan with 0.5 seconds on, 2.5 seconds off, had >90% passing rate. Conclusion: TrueBeam demonstrates excellent beam stability with minimal beam latencies under external device-based gated operations. Dosimetric measurements show minimal variation in beam energy, flatness, and plan delivery. Authors are employees of Varian Medical Systems, Inc

  11. SU-E-T-403: Evaluation of the Beam Performance of a Varian TrueBeam Linear Accelerator Under External Device-Based Gated Delivery Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kobulnicky, K; Pawlak, D; Purwar, A [Varian Medical Systems, Inc., Palo Alto, CA (United States)

    2015-06-15

    Purpose: To examine the beam performance of a Varian TrueBeam linear accelerator under external device-based gated delivery conditions. Methods: Six gating cycles were used to evaluate the gating performance of a standard production TrueBeam system that was not specially tuned in any way. The system was equipped with a factory installed external gating interface (EXGI). An in-house EXGI tester box was used to simulate the input gating signals. The gating cycles were selected based on long beam-on and short beam-off times, short beam-on and long beam-off times, or equal beam on and off times to check linac performance. The beam latencies were measured as the time difference between the logic high gating signal and the first or last target pulses with an oscilloscope. Tissue-Phantom Ratio, beam flatness, and dose distributions from 5 different plans were measured using the 6 different gating durations and the un-gated irradiation. A PTW 729 2-D array was used to compare 5 plans versus the un-gated delivery with a 1%/1mm gamma index passing criteria. Results: The beam latencies of the linac were based off of 20 samples for beam-on and beam-off, for each gating cycle. The average beam-on delays were measured to be between 57 and 66msec, with a maximum of 88 msec. The beam off latencies averaged between 19 and 26msec, with a maximum of 48 msec. TPR20,10 measurements showed beam energy stability within 0.5% of the un-gated delivery. Beam flatness was better than 2.5% for all gated cycles. All but two deliveries, the open field with 4 seconds on, 1 second off, and a five field IMRT plan with 0.5 seconds on, 2.5 seconds off, had >90% passing rate. Conclusion: TrueBeam demonstrates excellent beam stability with minimal beam latencies under external device-based gated operations. Dosimetric measurements show minimal variation in beam energy, flatness, and plan delivery. Authors are employees of Varian Medical Systems, Inc.

  12. 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.

  13. SU-G-201-13: Investigation of Dose Variation Induced by HDR Ir-192 Source Global Shift Within the Varian Ring Applicator Using Monte Carlo Methods

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y; Cai, J; Meltsner, S; Chang, Z; Craciunescu, O [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: The Varian tandem and ring applicators are used to deliver HDR Ir-192 brachytherapy for cervical cancer. The source path within the ring is hard to predict due to the larger interior ring lumen. Some studies showed the source could be several millimeters different from planned positions, while other studies demonstrated minimal dosimetric impact. A global shift can be applied to limit the effect of positioning offsets. The purpose of this study was to assess the necessities of implementing a global source shift using Monte Carlo (MC) simulations. Methods: The MCNP5 radiation transport code was used for all MC simulations. To accommodate TG-186 guidelines and eliminate inter-source attenuation, a BrachyVision plan with 10 dwell positions (0.5cm step sizes) was simulated as the summation of 10 individual sources with equal dwell times for simplification. To simplify the study, the tandem was also excluded from the MC model. Global shifts of ±0.1, ±0.3, ±0.5 cm were then simulated as distal and proximal from the reference positions. Dose was scored in water for all MC simulations and was normalized to 100% at the normalization point 0.5 cm from the cap in the ring plane. For dose comparison, Point A was 2 cm caudal from the buildup cap and 2 cm lateral on either side of the ring axis. With seventy simulations, 108 photon histories gave a statistical uncertainties (k=1) <2% for (0.1 cm)3 voxels. Results: Compared to no global shift, average Point A doses were 0.0%, 0.4%, and 2.2% higher for distal global shifts, and 0.4%, 2.8%, and 5.1% higher for proximal global shifts, respectively. The MC Point A doses differed by < 1% when compared to BrachyVision. Conclusion: Dose variations were not substantial for ±0.3 cm global shifts, which is common in clinical practice.

  14. SU-G-201-13: Investigation of Dose Variation Induced by HDR Ir-192 Source Global Shift Within the Varian Ring Applicator Using Monte Carlo Methods

    International Nuclear Information System (INIS)

    Yang, Y; Cai, J; Meltsner, S; Chang, Z; Craciunescu, O

    2016-01-01

    Purpose: The Varian tandem and ring applicators are used to deliver HDR Ir-192 brachytherapy for cervical cancer. The source path within the ring is hard to predict due to the larger interior ring lumen. Some studies showed the source could be several millimeters different from planned positions, while other studies demonstrated minimal dosimetric impact. A global shift can be applied to limit the effect of positioning offsets. The purpose of this study was to assess the necessities of implementing a global source shift using Monte Carlo (MC) simulations. Methods: The MCNP5 radiation transport code was used for all MC simulations. To accommodate TG-186 guidelines and eliminate inter-source attenuation, a BrachyVision plan with 10 dwell positions (0.5cm step sizes) was simulated as the summation of 10 individual sources with equal dwell times for simplification. To simplify the study, the tandem was also excluded from the MC model. Global shifts of ±0.1, ±0.3, ±0.5 cm were then simulated as distal and proximal from the reference positions. Dose was scored in water for all MC simulations and was normalized to 100% at the normalization point 0.5 cm from the cap in the ring plane. For dose comparison, Point A was 2 cm caudal from the buildup cap and 2 cm lateral on either side of the ring axis. With seventy simulations, 108 photon histories gave a statistical uncertainties (k=1) <2% for (0.1 cm)3 voxels. Results: Compared to no global shift, average Point A doses were 0.0%, 0.4%, and 2.2% higher for distal global shifts, and 0.4%, 2.8%, and 5.1% higher for proximal global shifts, respectively. The MC Point A doses differed by < 1% when compared to BrachyVision. Conclusion: Dose variations were not substantial for ±0.3 cm global shifts, which is common in clinical practice.

  15. Safe bunker designing for the 18 MV Varian 2100 Clinac: a comparison between Monte Carlo simulation based upon data and new protocol recommendations.

    Science.gov (United States)

    Beigi, Manije; Afarande, Fatemeh; Ghiasi, Hosein

    2016-01-01

    The aim of this study was to compare two bunkers designed by only protocols recommendations and Monte Carlo (MC) based upon data derived for an 18 MV Varian 2100Clinac accelerator. High energy radiation therapy is associated with fast and thermal photoneutrons. Adequate shielding against the contaminant neutron has been recommended by IAEA and NCRP new protocols. The latest protocols released by the IAEA (safety report No. 47) and NCRP report No. 151 were used for the bunker designing calculations. MC method based upon data was also derived. Two bunkers using protocols and MC upon data were designed and discussed. From designed door's thickness, the door designed by the MC simulation and Wu-McGinley analytical method was closer in both BPE and lead thickness. In the case of the primary and secondary barriers, MC simulation resulted in 440.11 mm for the ordinary concrete, total concrete thickness of 1709 mm was required. Calculating the same parameters value with the recommended analytical methods resulted in 1762 mm for the required thickness using 445 mm as recommended by TVL for the concrete. Additionally, for the secondary barrier the thickness of 752.05 mm was obtained. Our results showed MC simulation and the followed protocols recommendations in dose calculation are in good agreement in the radiation contamination dose calculation. Difference between the two analytical and MC simulation methods revealed that the application of only one method for the bunker design may lead to underestimation or overestimation in dose and shielding calculations.

  16. Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform); Applications cliniques de la radiotherapie guidee par l'image (RTGI)

    Energy Technology Data Exchange (ETDEWEB)

    Sorcini, B.; Tilikidis, A. [Karolinska Univ. Hospital, Dept. of Medical Physics, Stockholm (Sweden)

    2006-09-15

    Image-guided radiation therapy (IGRT) can be used to measure and correct positional errors for target and critical structures immediately prior to or during treatment delivery. Some of the most recent available methods applied for target localization are: trans-abdominal ultrasound, implanted markers with in room MV or kV X-rays, optical surface tracking systems, implantable electromagnetic markers, in room CT such as kVCT on rail, kilo-voltage or mega-voltage cone-beam CT (CBCT) and helical megavoltage CT. The verification of the accurate treatment position in conjunction with detailed anatomical information before every fraction can be essential for the outcome of the treatment. In this paper we present the on-board imager (OBI, Varian Medical Systems, Palo Alto, CA) that has been in routine clinical use at the Karolinska University Hospital since June 2004. The OBI has been used for on-line set-up correction of prostate patients using internal gold markers. Displacements of these markers can be monitored radiographically during the treatment course and the registered marker shifts act as a surrogate for prostate motion. For this purpose, on-board kV-kV seems to be an ideal system in terms of image quality. The CBCT function of OBI was installed in March 2005 at our department. It focuses on localizing tumors based on internal anatomy, not just on the conventional external marks or tattoos. The CBCT system provides the capacity for soft tissue imaging in the treatment position and real-time radiographic monitoring during treatment delivery. (authors)

  17. SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

    International Nuclear Information System (INIS)

    Deshpande, S; Dhote, D; Kumar, R; Thakur, K

    2015-01-01

    Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens doses were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT

  18. SU-F-J-42: Comparison of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Cranial Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, J; Shi, W; Andrews, D; Werner-Wasik, M; Lu, B; Yu, Y; Dicker, A; Liu, H [Thomas Jefferson University Hospital, Philadelphia, PA (United States)

    2016-06-15

    Purpose: To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac x-ray imaging systems for cranial radiotherapy. Method: Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (Version 2.5), which is integrated with a BrainLab ExacTrac imaging system (Version 6.1.1). The phantom study was based on a Rando head phantom, which was designed to evaluate isocenter-location dependence of the image registrations. Ten isocenters were selected at various locations in the phantom, which represented clinical treatment sites. CBCT and ExacTrac x-ray images were taken when the phantom was located at each isocenter. The patient study included thirteen patients. CBCT and ExacTrac x-ray images were taken at each patient’s treatment position. Six-dimensional image registrations were performed on CBCT and ExacTrac, and residual errors calculated from CBCT and ExacTrac were compared. Results: In the phantom study, the average residual-error differences between CBCT and ExacTrac image registrations were: 0.16±0.10 mm, 0.35±0.20 mm, and 0.21±0.15 mm, in the vertical, longitudinal, and lateral directions, respectively. The average residual-error differences in the rotation, roll, and pitch were: 0.36±0.11 degree, 0.14±0.10 degree, and 0.12±0.10 degree, respectively. In the patient study, the average residual-error differences in the vertical, longitudinal, and lateral directions were: 0.13±0.13 mm, 0.37±0.21 mm, 0.22±0.17 mm, respectively. The average residual-error differences in the rotation, roll, and pitch were: 0.30±0.10 degree, 0.18±0.11 degree, and 0.22±0.13 degree, respectively. Larger residual-error differences (up to 0.79 mm) were observed in the longitudinal direction in the phantom and patient studies where isocenters were located in or close to frontal lobes, i.e., located superficially. Conclusion: Overall, the average residual-error differences were within 0.4 mm in the translational

  19. TH-EF-BRB-10: Dosimetric Validation of a Trajectory Based Cranial SRS Treatment Technique On a Varian TrueBeam Linac

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B [University of British Columbia, Vancouver, BC (Canada); Vancouver Cancer Centre, Vancouver, BC (Canada); Gete, E [Vancouver Cancer Centre, Vancouver, BC (Canada)

    2016-06-15

    Purpose: This work investigates the dosimetric accuracy of a trajectory based delivery technique in which an optimized radiation beam is delivered along a Couch-Gantry trajectory that is formed by simultaneous rotation of the linac gantry and the treatment couch. Methods: Nine trajectory based cranial SRS treatment plans were created using in-house optimization software. The plans were calculated for delivery on the TrueBeam STx linac with 6MV photon beam. Dose optimization was performed along a user-defined trajectory using MLC modulation, dose rate modulation and jaw tracking. The pre-defined trajectory chosen for this study is formed by a couch rotation through its full range of 180 degrees while the gantry makes four partial arc sweeps which are 170 degrees each. For final dose calculation, the trajectory based plans were exported to the Varian Eclipse Treatment Planning System. The plans were calculated on a homogeneous cube phantom measuring 18.2×18.2×18.2 cm3 with the analytical anisotropic algorithm (AAA) using a 1mm3 calculation voxel. The plans were delivered on the TrueBeam linac via the developer’s mode. Point dose measurements were performed on 9 patients with the IBA CC01 mini-chamber with a sensitive volume of 0.01 cc. Gafchromic film measurements along the sagittal and coronal planes were performed on three of the 9 treatment plans. Point dose values were compared with ion chamber measurements. Gamma analysis comparing film measurement and AAA calculations was performed using FilmQA Pro. Results: The AAA calculations and measurements were in good agreement. The point dose difference between AAA and ion chamber measurements were within 2.2%. Gamma analysis test pass rates (2%, 2mm passing criteria) for the Gafchromic film measurements were >95%. Conclusion: We have successfully tested TrueBeam’s ability to deliver accurate trajectory based treatments involving simultaneous gantry and couch rotation with MLC and dose rate modulation along the

  20. Evaluation of latent variances in Monte Carlo dose calculations with Varian TrueBeam photon phase-spaces used as a particle source

    Science.gov (United States)

    Alhakeem, Eyad; Zavgorodni, Sergei

    2018-01-01

    The purpose of this study was to evaluate the latent variance (LV) of Varian TrueBeam photon phase-space files (PSF) for open 10  ×  10 cm2 and small stereotactic fields and estimate the number of phase spaces required to be summed up in order to maintain sub-percent LV in Monte Carlo (MC) dose calculations. BEAMnrc/DOSXYZnrc software was used to transport particles from Varian phase-space files (PSFA) through the secondary collimators. Transported particles were scored into another phase-space located under the jaws (PSFB), or transported further through the cone collimators and scored straight below, forming PSFC. Phase-space files (PSFB) were scored for 6 MV-FFF, 6 MV, 10 MV-FFF, 10 MV and 15 MV beams with 10  ×  10 cm2 field size, and PSFC were scored for 6 MV beam under circular cones of 0.13, 0.25, 0.35, and 1 cm diameter. Both PSFB and PSFC were transported into a water phantom with particle recycling number ranging from 10 to 1000. For 10  ×  10 cm2 fields 0.5  ×  0.5  ×  0.5 cm3 voxels were used to score the dose, whereas the dose was scored in 0.1  ×  0.1  ×  0.5 cm3 voxels for beams collimated with small cones. In addition, for small 0.25 cm diameter cone-collimated 6 MV beam, phantom voxel size varied as 0.02  ×  0.02  ×  0.5 cm3, 0.05  ×  0.05  ×  0.5 cm3 and 0.1  ×  0.1  ×  0.5 cm3. Dose variances were scored in all cases and LV evaluated as per Sempau et al. For the 10  ×  10 cm2 fields calculated LVs were greatest at the phantom surface and decreased with depth until they reached a plateau at 5 cm depth. LVs were found to be 0.54%, 0.96%, 0.35%, 0.69% and 0.57% for the 6 MV-FFF, 6 MV, 10 MV-FFF, 10 MV and 15 MV energies, respectively at the depth of 10 cm. For the 6 MV phase-space collimated with cones of 0.13, 0.25, 0.35, 1.0 cm diameter, the LVs calculated at 1.5 cm depth were 75.6%, 25.4%, 17

  1. 2 MW 110 GHz ECH heating system for DIII-D

    International Nuclear Information System (INIS)

    Moeller, C.; Prater, R.; Callis, R.; Remsen, D.; Doane, J.; Cary, W.; Phelps, R.; Tupper, M.

    1990-09-01

    A 2 MW 110 GHz ECH system using Varian 0.5 MW gyrotrons is under construction for use on the DIII-D tokamak by late 1991. Most of the components are being design and fabricated at General Atomics, including the gyrotron tanks, superconducting magnets, and transmission line. These components are intended for operation with 10 second pulses and, in the future, with 1 MW gyrotrons. 6 refs., 5 figs

  2. SU-E-J-47: Comparison of Online Image Registrations of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac Imaging Systems

    International Nuclear Information System (INIS)

    Li, J; Shi, W; Andrews, D; Werner-Wasik, M; Yu, Y; Liu, H

    2015-01-01

    Purpose To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac imaging systems. Methods Tests were performed on a Varian TrueBeam STx linear accelerator (Version 2.0), which is integrated with a BrainLab ExacTrac imaging system (Version 6.0.5). The study was focused on comparing the online image registrations for translational shifts. A Rando head phantom was placed on treatment couch and immobilized with a BrainLab mask. The phantom was shifted by moving the couch translationally for 8 mm with a step size of 1 mm, in vertical, longitudinal, and lateral directions, respectively. At each location, the phantom was imaged with CBCT and ExacTrac x-ray. CBCT images were registered with TrueBeam and ExacTrac online registration algorithms, respectively. And ExacTrac x-ray image registrations were performed. Shifts calculated from different registrations were compared with nominal couch shifts. Results The averages and ranges of absolute differences between couch shifts and calculated phantom shifts obtained from ExacTrac x-ray registration, ExacTrac CBCT registration with default window, ExaxTrac CBCT registration with adjusted window (bone), Truebeam CBCT registration with bone window, and Truebeam CBCT registration with soft tissue window, were: 0.07 (0.02–0.14), 0.14 (0.01–0.35), 0.12 (0.02–0.28), 0.09 (0–0.20), and 0.06 (0–0.10) mm, in vertical direction; 0.06 (0.01–0.12), 0.27 (0.07–0.57), 0.23 (0.02–0.48), 0.04 (0–0.10), and 0.08 (0– 0.20) mm, in longitudinal direction; 0.05 (0.01–0.21), 0.35 (0.14–0.80), 0.25 (0.01–0.56), 0.19 (0–0.40), and 0.20 (0–0.40) mm, in lateral direction. Conclusion The shifts calculated from ExacTrac x-ray and TrueBeam CBCT registrations were close to each other (the differences between were less than 0.40 mm in any direction), and had better agreements with couch shifts than those from ExacTrac CBCT registrations. There were no significant differences between True

  3. Observation of dynamic interactions between fundamental and second-harmonic modes in a high-power sub-terahertz gyrotron operating in regimes of soft and hard self-excitation.

    Science.gov (United States)

    Saito, Teruo; Tatematsu, Yoshinori; Yamaguchi, Yuusuke; Ikeuchi, Shinji; Ogasawara, Shinya; Yamada, Naoki; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka

    2012-10-12

    Dynamic mode interaction between fundamental and second-harmonic modes has been observed in high-power sub-terahertz gyrotrons [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009); T. Saito et al. Phys. Plasmas 19, 063106 (2012)]. Interaction takes place between a parasitic fundamental or first-harmonic (FH) mode and an operating second-harmonic (SH) mode, as well as among SH modes. In particular, nonlinear excitation of the parasitic FH mode in the hard self-excitation regime with assistance of a SH mode in the soft self-excitation regime was clearly observed. Moreover, both cases of stable two-mode oscillation and oscillation of the FH mode only were observed. These observations and theoretical analyses of the dynamic behavior of the mode interaction verify the nonlinear hard self-excitation of the FH mode.

  4. Measurements Techniques for Gyrotron characterization

    International Nuclear Information System (INIS)

    Castro, P.J. de.

    1987-08-01

    Experiments planned for the characterization of the 35GHz girotron, which is being built at the Plasma Laboratory of INPE, are described. The methods of the measurements are presented and the required instrumentation and devices are specified. Special attention is given to the measurement techniques of the resonator electric field profile. (author) [pt

  5. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    Science.gov (United States)

    Srivastava, Vishnu

    2012-11-01

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  6. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    International Nuclear Information System (INIS)

    Srivastava, Vishnu

    2012-01-01

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  7. SU-E-J-13: Six Degree of Freedom Image Fusion Accuracy for Cranial Target Localization On the Varian Edge Stereotactic Radiosurgery System: Comparison Between 2D/3D and KV CBCT Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H [Wayne State University, Detroit, MI (United States); Song, K; Chetty, I; Kim, J [Henry Ford Health System, Detroit, MI (United States); Wen, N [Henry Ford Health System, West Bloomfield, MI (United States)

    2015-06-15

    Purpose: To determine the 6 degree of freedom systematic deviations between 2D/3D and CBCT image registration with various imaging setups and fusion algorithms on the Varian Edge Linac. Methods: An anthropomorphic head phantom with radio opaque targets embedded was scanned with CT slice thicknesses of 0.8, 1, 2, and 3mm. The 6 DOF systematic errors were assessed by comparing 2D/3D (kV/MV with CT) with 3D/3D (CBCT with CT) image registrations with different offset positions, similarity measures, image filters, and CBCT slice thicknesses (1 and 2 mm). The 2D/3D registration accuracy of 51 fractions for 26 cranial SRS patients was also evaluated by analyzing 2D/3D pre-treatment verification taken after 3D/3D image registrations. Results: The systematic deviations of 2D/3D image registration using kV- kV, MV-kV and MV-MV image pairs were within ±0.3mm and ±0.3° for translations and rotations with 95% confidence interval (CI) for a reference CT with 0.8 mm slice thickness. No significant difference (P>0.05) on target localization was observed between 0.8mm, 1mm, and 2mm CT slice thicknesses with CBCT slice thicknesses of 1mm and 2mm. With 3mm CT slice thickness, both 2D/3D and 3D/3D registrations performed less accurately in longitudinal direction than thinner CT slice thickness (0.60±0.12mm and 0.63±0.07mm off, respectively). Using content filter and using similarity measure of pattern intensity instead of mutual information, improved the 2D/3D registration accuracy significantly (P=0.02 and P=0.01, respectively). For the patient study, means and standard deviations of residual errors were 0.09±0.32mm, −0.22±0.51mm and −0.07±0.32mm in VRT, LNG and LAT directions, respectively, and 0.12°±0.46°, −0.12°±0.39° and 0.06°±0.28° in RTN, PITCH, and ROLL directions, respectively. 95% CI of translational and rotational deviations were comparable to those in phantom study. Conclusion: 2D/3D image registration provided on the Varian Edge radiosurgery, 6 DOF

  8. SU-E-J-13: Six Degree of Freedom Image Fusion Accuracy for Cranial Target Localization On the Varian Edge Stereotactic Radiosurgery System: Comparison Between 2D/3D and KV CBCT Image Registration

    International Nuclear Information System (INIS)

    Xu, H; Song, K; Chetty, I; Kim, J; Wen, N

    2015-01-01

    Purpose: To determine the 6 degree of freedom systematic deviations between 2D/3D and CBCT image registration with various imaging setups and fusion algorithms on the Varian Edge Linac. Methods: An anthropomorphic head phantom with radio opaque targets embedded was scanned with CT slice thicknesses of 0.8, 1, 2, and 3mm. The 6 DOF systematic errors were assessed by comparing 2D/3D (kV/MV with CT) with 3D/3D (CBCT with CT) image registrations with different offset positions, similarity measures, image filters, and CBCT slice thicknesses (1 and 2 mm). The 2D/3D registration accuracy of 51 fractions for 26 cranial SRS patients was also evaluated by analyzing 2D/3D pre-treatment verification taken after 3D/3D image registrations. Results: The systematic deviations of 2D/3D image registration using kV- kV, MV-kV and MV-MV image pairs were within ±0.3mm and ±0.3° for translations and rotations with 95% confidence interval (CI) for a reference CT with 0.8 mm slice thickness. No significant difference (P>0.05) on target localization was observed between 0.8mm, 1mm, and 2mm CT slice thicknesses with CBCT slice thicknesses of 1mm and 2mm. With 3mm CT slice thickness, both 2D/3D and 3D/3D registrations performed less accurately in longitudinal direction than thinner CT slice thickness (0.60±0.12mm and 0.63±0.07mm off, respectively). Using content filter and using similarity measure of pattern intensity instead of mutual information, improved the 2D/3D registration accuracy significantly (P=0.02 and P=0.01, respectively). For the patient study, means and standard deviations of residual errors were 0.09±0.32mm, −0.22±0.51mm and −0.07±0.32mm in VRT, LNG and LAT directions, respectively, and 0.12°±0.46°, −0.12°±0.39° and 0.06°±0.28° in RTN, PITCH, and ROLL directions, respectively. 95% CI of translational and rotational deviations were comparable to those in phantom study. Conclusion: 2D/3D image registration provided on the Varian Edge radiosurgery, 6 DOF

  9. Prospects for development of powerful, highly efficient, relativistic gyrodevices

    International Nuclear Information System (INIS)

    Nusinovich, G.S.; Granatstein, V.L.

    1992-01-01

    For various applications the required parameters of sources of powerful microwave radiation lie far beyond the capabilities of existing tubes. This provokes an interest in reconsidering basic principles of relevant microwave sources in order to search for alternative concepts in their development. One of the most promising devices in the short-wavelength region of microwaves is the cyclotron resonance maser (CRM). During the last decade, two important varieties of CRMs have been distinguished, namely, gyrotrons, which operate at frequencies close to cut-off, and cyclotron autoresonance masers (CARMs), which operate at frequencies far from cut-off. When the axial phase velocity of the wave in properly adjusted to the beam voltage and electron pitch-ratio, the efficiency of relativistic CRMs may be high (≥50%). The method of optimizing efficiency based on a partial compensation of the shift in the relativistic electron cyclotron frequency by the change in the Doppler term can be, in principle, accompanied by a corresponding profiling of the external magnetic field and/or the wave phase velocity in a slightly irregular waveguide. These methods can be used in such relativistic CRMs as relativistic gyrotrons, gyroklystrons, gyro-traveling-wave-tubes and gyrotwistrons. The most important point is their sensitivity to a spread in electron parameters. As the beam voltage grows, the operation becomes more sensitive. However, at relatively low voltages such devices are quite tolerant to electron velocity spread

  10. Use of I.G.R.T. for prostate cancers (O.B.I.-C.B.C.T. VarianTM, ExacTrac BrainLABTM and M.V.C.T. Tomo-therapy)

    International Nuclear Information System (INIS)

    Delpon, G.; Llagostera, C.; Lisbona, A.; Le Blanc, M.; Rio, E.; Supiot, S.; Mahe, M.A.

    2009-01-01

    Introduction: The aim of this work was to report the experience of image-guided radiotherapy at the C.L.C.C. Nantes-Atlantique using three repositioning imaging devices, the ExacTrac (BrainLABTM), the on-board imager cone beam computed tomography (O.B.I.-C.B.C.T.) (Varian TM ) and the M.V.C.T. (Tomotherapy Inc TM ), in the case of prostate external radiotherapy.Material and methods: For each linac and its imaging device, a treatment plan was described. Moreover, studies concerning calculated shifts after imaging sessions were achieved. Using ExacTrac, for eight patients, a study compared daily shifts based on bony anatomy or on implanted markers. Considering mean values of displacements over a course of radiotherapy, dosimetric impact was evaluated. With the O.B.I.-C.B.C.T., two imaging modalities were used, kV-kV (0. and 270.) and C.B.C.T.. Up to now, whatever the images, displacements were calculated using the bony anatomy. For both modalities and for 26 patients, shifts were compared. Since the beginning of the Tomotherapy HiArt use, mega voltage cone tomography (M.V.C.T.) was performed for each session of each patient. For 12 patients, mean displacements were calculated after five fractions. Then the deviations to those values were calculated. This was done to show the relevance of daily M.V.C.T.. Results and conclusion: This work allows us to report the use of three repositioning imaging devices in the radiotherapy department. At least: they provide an efficient positioning tool. And they let us see the future radiotherapy which would probably be the dose-guided radiotherapy. (N.C.)

  11. Electronic tissue compensation achieved with both dynamic and static multileaf collimator in eclipse treatment planning system for Clinac 6 EX and 2100 CD Varian linear accelerators: Feasibility and dosimetric study

    Directory of Open Access Journals (Sweden)

    Kinhikar Rajesh

    2007-01-01

    Full Text Available Dynamic multileaf collimator (DMLC and static multileaf collimator (SMLC, along with three-dimensional treatment planning system (3-D TPS, open the possibility of tissue compensation. A method using electronic tissue compensator (ETC has been implemented in Eclipse 3-D TPS (V 7.3, Varian Medical Systems, Palo Alto, USA at our center. The ETC was tested for head and neck conformal radiotherapy planning. The purpose of this study was to verify the feasibility of DMLC and SMLC in head and neck field irradiation for delivering homogeneous dose in the midplane at a pre-defined depth. In addition, emphasis was given to the dosimetric aspects in commissioning ETC in Eclipse. A Head and Neck Phantom (The Phantom Laboratory, USA was used for the dosimetric verification. Planning was carried out for both DMLC and SMLC ETC plans. The dose calculated at central axis by eclipse with DMLC and SMLC was noted. This was compared with the doses measured on machine with ion chamber and thermoluminescence dosimetry (TLD. The calculated isodose curves and profiles were compared with the measured ones. The dose profiles along the two major axes from Eclipse were also compared with the profiles obtained from Amorphous Silicon (AS500 Electronic portal imaging device (EPID on Clinac 6 EX machine. In uniform dose regions, measured dose values agreed with the calculated doses within 3%. Agreement between calculated and measured isodoses in the dose gradient zone was within 3 mm. The isodose curves and the profiles were found to be in good agreement with the measured curves and profiles. The measured and the calculated dose profiles along the two major axes were flat for both DMLC and SMLC. The dosimetric verification of ETC for both the linacs demonstrated the feasibility and the accuracy of the ETC treatment modality for achieving uniform dose distributions. Therefore, ETC can be used as a tool in head and neck treatment planning optimization for improved dose uniformity.

  12. Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery.

    Science.gov (United States)

    Li, Jun; Shi, Wenyin; Andrews, David; Werner-Wasik, Maria; Lu, Bo; Yu, Yan; Dicker, Adam; Liu, Haisong

    2017-06-01

    The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery. Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient's treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared. In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences were cone-beam computed tomography image registration in intracranial treatments.

  13. RECENT DEVELOPMENTS ON THE 110 GHz ELECTRON CYCLOTRON INSTATLLATION ON THE DIII-D TOKAMAK

    International Nuclear Information System (INIS)

    PONCE, D.; CALLIS, R.W.; CARY, W.P.; FERRON, J.R.; GREEN, M.; GRUNLOH, H.J.; GORELOV, Y.; LOHR, J.; ELLIS, R.A.

    2002-01-01

    OAK A271 RECENT DEVELOPMENTS ON THE 110 GHZ ELECTRON CYCLOTRON INSTALLATION ON THE DIII-D TOKAMAK. Significant improvements are being implement4ed to the capability of the 110 GHz electron cyclotron system on the DIII-D tokamak. Chief among these is the addition of the fifth and sixth 1 MW class gyrotrons, increasing the power available for auxiliary heating and current drive by nearly 60%. These tubes use artificially grown diamond rf output windows to obtain high power with long pulse capability. The beams from these tubes are nearly Gaussian, facilitating coupling to the waveguide. A new fully articulating dual launcher capable of high speed spatial scanning has been designed and tested. The launcher has two axis independent steering for each waveguide. the mirrors can be rotated at up to 100 o /s. A new feedback system linking the DIII-D Plasma Control System (PCS) with the gyrotron beam voltage waveform generators permits real-time feedback control of some plasma properties such as electron temperature. The PCS can use a variety of plasma monitors to generate its control signal, including electron cyclotron emission and Mirnov probes. Electron cyclotron heating and electron cyclotron current drive (ECH and ECCD) were used during this year's DIII-D experimental campaign to control electron temperature, density, and q profiles, induce an ELM-free H-mode, and suppress the m=2/n=1 neoclassical tearing mode. The new capabilities have expanded the role of EC systems in tokamak plasma control

  14. ECH system developments including the design of an intelligent fault processor on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Ponce, D.; Lohr, J.; Tooker, J.F.; O'Neill, R.C.; Moeller, C.P.; Doane, J.L.; Noraky, S.; Dubovenko, K.; Gorelov, Y.A.; Cengher, M.; Penaflor, B.G.; Ellis, R.A.

    2011-01-01

    A new generation fault processor is in development which is intended to increase fault handling flexibility and reduce the number of incomplete DIII-D shots due to gyrotron faults. The processor, which is based upon a field programmable gate array device, will analyze signals for aberrant operation and ramp down high voltage to try to avoid hard faults. The processor will then attempt to ramp back up to an attainable operating point. The new generation fault processor will be developed during an expansion of the electron cyclotron heating (ECH) areas that will include the installation of a depressed collector gyrotron and associated equipment. Existing systems will also be upgraded. Testing of real-time control of the ECH launcher poloidal drives by the DIII-D plasma control system will be completed. The ECH control system software will be upgraded for increased scalability and to increase operator productivity. Resources permitting, all systems will receive an extra layer of interlocks for the filament and magnet power supplies, added shielding for the tank electronics, programmable filament boost shape for long pulses, and electronics upgrades for the installation of the advanced fault processor.

  15. HV Switch Tube Development Program status report: April 28, 1978

    International Nuclear Information System (INIS)

    Winje, R.A.

    1978-01-01

    The HV Switch Tube Development Program encompassed development contracts to both Eimac (Division of Varian) and RCA. Both companies were required to develop a design for the tube and to build and test two tubes. The development program began in April, 1976. Currently, both companies have built tubes; Eimac has built one and RCA has built two. As initially built, both tubes exhibited unstable operation; however, RCA has implemented design changes which stabilized the tube operation. Eimac has a design modification which they believe will produce stable operation when the change is implemented. Both tubes have been tested to a limited degree and no other abnormal characteristics have been observed

  16. A PROPOSED NOVEL ARCHITECTURE OF EC CONTROL SYSTEM USING IEEE 802.11n NETWORK AT ITER-INDIA GYROTRON TEST FACILITY

    Directory of Open Access Journals (Sweden)

    Deepak Mandge

    2017-06-01

    Full Text Available IEEE 802.11 Wi-Fi networks are increasingly becoming popular for its use in industrial applications. With the availability of recent amendments to IEEE 802.11 series of standards, particularly IEEE 802.11n, the adoption of Wi-Fi networks for process automation is gaining more focus and importance. The installation of Wireless networks naturally provides reduction in cable and its maintenance related costs, provides increased flexibility and mobility to enhance performance of industrial control system. The IEEE 802.11n supports parameterization that can be set for particular industrial applications and hence it has addressed to the aspects of timeliness and criticality to some extent. This paper proposes the use of IEEE 802.11n network to interconnect field instruments with Siemens PLC controller in harsh EMI/EMC environment. An application example is shown where the alternate control system architecture is developed in which non-critical and non-safety signals are communicated over Wi-Fi. While, for critical and safety signals, traditional hardwired signals methods can be implemented.

  17. Development of CVD Diamond for Industrial Applications Final Report CRADA No. TC-2047-02

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Olstad, R. [General Atomics, San Diego, CA (United States); Jory, H. [Communications and Power Industries, Palo Alto, CA (United States); Vikharov, A. L. [Russian Academy of Sciences (RAS), Moscow (Russian Federation)

    2017-09-08

    This project was a collaborative effort to develop and demonstrate a new millimeter microwave assisted chemical vapor deposition(CVD) process for manufacturing large diamond disks with greatly reduced processing times and costs from those now available. In the CVD process, carbon based gases (methane) and hydrogen are dissociated into plasma using microwave discharge and then deposited layer by layer as polycrystalline diamond onto a substrate. The available low frequency (2.45GHz) microwave sources used elsewhere (De Beers) result in low density plasmas and low deposition rates: 4 inch diamond disks take 6-8 weeks to process. The new system developed in this project uses a high frequency 30GHz Gyrotron as the microwave source and a quasi-optical CVD chamber resulting in a much higher density plasma which greatly reduced the diamond processing times (1-2 weeks)

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

    International Nuclear Information System (INIS)

    Vernon, R.J.

    1989-08-01

    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 Te 15,2 --TE 15, 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 TE 15,2 --TE 15,1 converter for possible use with the Varian 140 GHz gyrotron was also developed. Work was begun on a combined TE 15,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 TE 0n and TM 0n 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 TE 0n modes in a circular waveguide. 15 refs., 15 figs

  19. Development.

    Science.gov (United States)

    Boydell, Tom

    1982-01-01

    Explores the theories and models of self-actualization and human development. Twelve tables illustrate developmental stages, ways of knowing, moral and ethical development, management style, goals of learning, organizational development, and other dimensions. Availability: M.E.A.D. Subscriptions, C.S.M.L., University of Lancaster, Lancaster LA1…

  20. GA microwave window development

    International Nuclear Information System (INIS)

    Moeller, C.P.; Kasugai, A.; Sakamoto, K.; Takahashi, K.

    1994-10-01

    The GA prototype distributed window was tested in a 32 mm diam. waveguide system at a power density suitable for a MW gyrotron, using the JAERI/Toshiba 110 GHz long pulse internal converter gyrotron in the JAERI test stand. The presence of the untilted distributed window had no adverse effect on the gyrotron operation. A pulse length of 10 times the calculated thermal equilibrium time (1/e time) of 30 msec was reached, and the window passed at least 750 pulses greater than 30 msec and 343 pulses greater than 60 msec. Beyond 100 msec, the window calorimetry reached steady state, allowing the window dissipation to be measured in a single pulse. The measured loss of 4.0% agrees both with the estimated loss, on which the stress calculations are based, and with the attenuation measured at low power in the HE 11 mode. After the end of the tests, the window was examined; no evidence of arcing air coating was found in the part of the window directly illuminated by the microwaves, although there was discoloration in a recess containing an optical diagnostic which outgassed, causing a local discharge to occur in that recess. Finally, there was no failure of the metal-sapphire joints during a total operating time of 50 seconds consisting of pulses longer than 30 msec

  1. Developer

    OpenAIRE

    Lakew, Lakachew

    2016-01-01

    As companies grow managing the work becomes harder and harder, thus the ad-vantages of technology come into hand for increasing communication and facili-tating work. This thesis documents the design and development of a web and mobile applica-tion for a service company. The web and mobile applications are built using Laravel and Android Studio respectively. These two applications are designed to communicate with one another so that similar data can be used across these two platforms. ...

  2. Validation of Varian's AAA algorithm with focus on lung treatments

    International Nuclear Information System (INIS)

    Roende, Heidi S.; Hoffmann, Lone

    2009-01-01

    The objective of this study was to examine the accuracy of the Anisotropic Analytical Algorithm (AAA). A variety of different field configurations in homogeneous and in inhomogeneous media (lung geometry) was tested for the AAA algorithm. It was also tested against the present Pencil Beam Convolution (PBC) algorithm. Materials and methods. Two dimensional (2D) dose distributions were measured for a variety of different field configurations in solid water with a 2D array of ion chambers. The dose distributions of patient specific treatment plans in selected transversal slices were measured in a Thorax lung phantom with Gafchromic dosimetry films. A Farmer ion chamber was used to check point doses in the Thorax phantom. The 2D dose distributions were evaluated with a gamma criterion of 3% in dose and 3 mm distance to agreement (DTA) for the 2D array measurements and for the film measurements. Results. For AAA, all fields tested in homogeneous media fulfilled the criterion, except asymmetric fields with wedges and intensity modulated plans where deviations of 5 and 4%, respectively, were seen. Overall, the measured and calculated 2D dose distributions for AAA in the Thorax phantom showed good agreement - both for 6 and 15 MV photons. More than 80% of the points in the high dose regions met the gamma criterion, though it failed at low doses and at gradients. For the PBC algorithm only 30-70% of the points met the gamma criterion. Conclusion. The AAA algorithm has been shown to be superior to the PBC algorithm in heterogeneous media, especially for 15 MV. For most treatment plans the deviations in the lung and the mediastinum regions are below 3%. However, the algorithm may underestimate the dose to the spinal cord by up to 7%

  3. CBH1 homologs and varian CBH1 cellulase

    Energy Technology Data Exchange (ETDEWEB)

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Neefe, Paulien

    2014-07-01

    Disclosed are a number of homologs and variants of Hypocrea jecorina Cel7A (formerly Trichoderma reesei cellobiohydrolase I or CBH1), nucleic acids encoding the same and methods for producing the same. The homologs and variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted and/or deleted.

  4. Development and contribution of rf heating and current drive systems to long pulse, high performance experiments in JT-60U

    International Nuclear Information System (INIS)

    Moriyama, Shinichi; Seki, Masami; Terakado, Masayuki; Shimono, Mitsugu; Ide, Shunsuke; Isayama, Akihiko; Suzuki, Takahiro; Fujii, Tsuneyuki

    2005-01-01

    To contribute to high performance long pulse (∼65 s) experiments in JT-60U, the target of the electron cyclotron (EC) operation in long pulse is 0.6 MW for 30 s with four gyrotrons, though 10 MJ (2.8 MW and 3.6 s) was achieved in high power operation before 2003. One of the critical issues for the long pulse operation is detuning due to decay in beam current of the gyrotron. This decay comes from the cathode cooling by continuous electron emission. As a countermeasure for this issue, active adjustments for the heater current and anode voltage during the pulse have successfully extended the duration of a good oscillation condition for the gyrotron. As a result, 0.4 MW for 16 s with one gyrotron to the dummy load and for 8.7 s to the plasma have been achieved up to now

  5. Annual Progress Report on Contract AFOSR-81-0093, March 15, 1984 to March 14, 1985,

    Science.gov (United States)

    1985-04-30

    pulsar period. A recent development in pulsars was the observation of a pulsar outside our galaxy in the large { ( Magellanic cloud , with a period of 0.9...gyrotrons and other cyclotron masers. A. Goldenberg of the USSR gave a survey paper on gyrotron research in the USSR. He is from the city of Gorky...gas at 1 atmosphere, the purpose of which was not specified. G. L. Granatstein of the Naval Research Laboratory then gave a paper on Gyrotron and other

  6. 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.

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

    International Nuclear Information System (INIS)

    Thumm, M.

    1993-10-01

    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 P out = 0.58 MW, pulse length τ = 2.0 s and efficiency η = 34% are commercially available. Diagnostic gyrotrons deliver P out = 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, P out = 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: P out = 2 GW, τ = 20 ns, η = 13% at 140 GHz (LLNL) and P out = 15 kW, τ = 20 μs, η = 5% in the range from 120 to 900 GHz (UCSB). (orig.) [de

  8. Maturing ECRF technology for plasma control

    International Nuclear Information System (INIS)

    Callis, R.W.; .; Cary, W.P.; Chu, S.

    2003-01-01

    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)

  9. Development of Geometrical Quality Control Real-time Analysis Program using an Electronic Portal Imaging

    International Nuclear Information System (INIS)

    Lee, Sang Rok; Jung, Kyung Yong; Jang, Min Sun; Lee, Byung Gu; Kwon, Young Ho

    2012-01-01

    To develop a geometrical quality control real-time analysis program using an electronic portal imaging to replace film evaluation method. A geometrical quality control item was established with the Eclipse treatment planning system (Version 8.1, Varian, USA) after the Electronic Portal Imaging Device (EPID) took care of the problems occurring from the fixed substructure of the linear accelerator (CL-iX, Varian, USA). Electronic portal image (single exposure before plan) was created at the treatment room's 4DTC (Version 10.2, Varian, USA) and a beam was irradiated in accordance with each item. The gaining the entire electronic portal imaging at the Off-line review and was evaluated by a self-developed geometrical quality control real-time analysis program. As for evaluation methods, the intra-fraction error was analyzed by executing 5 times in a row under identical conditions and procedures on the same day, and in order to confirm the infer-fraction error, it was executed for 10 days under identical conditions of all procedures and was compared with the film evaluation method using an Iso-align quality control device. Measurement and analysis time was measured by sorting the time into from the device setup to data achievement and the time amount after the time until the completion of analysis and the convenience of the users and execution processes were compared. The intra-fraction error values for each average 0.1, 0.2, 0.3, 0.2 mm at light-radiation field coincidence, collimator rotation axis, couch rotation axis and gantry rotation axis. By checking the infer-fraction error through 10 days of continuous quality control, the error values obtained were average 1.7, 1.4, 0.7, 1.1 mm for each item. Also, the measurement times were average 36 minutes, 15 minutes for the film evaluation method and electronic portal imaging system, and the analysis times were average 30 minutes, 22 minutes. When conducting a geometrical quality control using an electronic portal imaging

  10. Competition between modes with different axial structures in gyrotrons

    International Nuclear Information System (INIS)

    Khutoryan, Eduard M.; Nusinovich, Gregory S.; Sinitsyn, Oleksandr V.

    2014-01-01

    This study was motivated by some experiments in which it was found that during the voltage rise, instead of expected excitation of a high-frequency parasitic mode, the excitation of a lower-frequency parasitic mode takes place in a certain range of voltages. For explaining this fact, the dependence of start currents of possible competing modes on the beam voltage was carried out in the cold-cavity approximation and by using the self-consistent approach. It was found that in the case of cavities, which consist of the combination of a section of constant radius waveguide and a slightly uptapered waveguide, these two approaches yield completely different results. Thus, experimentally observed excitation of the low-frequency parasitic mode can be explained by the self-consistent modification of the axial profile of the excited field, which has strong influence on the diffractive quality factor of competing modes. This modification is especially pronounced in the case of excitation of modes with many axial variations which can be excited in the region of beam interaction with the backward-wave component of such modes

  11. Construction of a 35 GHz 100 kW gyrotron

    International Nuclear Information System (INIS)

    Aso, Y.; Barroso, J.J.; Castro, P.J.; Correa, R.A.; Ludwing, G.O.; Montes, A.; Morgado, U.T.F.; Nono, M.C.A.; Rossi, J.O.; Silva, P.R.

    1989-09-01

    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

  12. Development of ECR ion source and LEBT technology for RIA

    International Nuclear Information System (INIS)

    Leitner, Daniela; Lyneis, Claude M.; Abbott, Steven R.; Dwinell, Roger D.; Leitner, Matthaeus; Silver, Charles S.; Taylor, Clyde E.

    2004-01-01

    The Rare Isotope Accelerator (RIA) Linac driver requires a great variety of high charge state ion beams with up to a magnitude higher intensity than currently achievable for the heaviest masses. The goal of the RIA injector R and D program for VENUS is the reliable production of intense medium charge state ion beams, e.g., 8 puA (particle mu A) of U29+. Therefore, the superconducting ECR ion source VENUS has been designed from the beginning for optimum operation at 28 GHz at high power (10 kW). In addition, a high intensity Low Energy Beam Transport, LEBT, that was developed to analyze and transport these multiply-charged, space charge dominated beams. During the last year VENUS was commissioned at 18 GHz and preparations for 28 GHz operation continued. Tests with various gases and recently metals have been performed with up to 2000 W of 18 GHz RF power. Promising performance has been measured in those preliminary beam tests. For example, 180 p mu A of O6+, 15 p mu A of Ar12+, 7.5 puA of X e20+ and 4puA of Bi24+ were produced in the early commissioning phase, ranking VENUS among the currently highest performance 18 GHz ECR ion sources. In FY04 a 10 kW 28 gyrotron system will be added, which will enable VENUS to reach full performance. The emittance of the beams produced at 18 GHz was measured with a two axis emittance scanner developed with earlier RIA R and D funds

  13. Study and development of different techniques for the generation, conversion, propagation, and radiation of high power microwaves for the electronic cyclotron frequency plasma heating

    International Nuclear Information System (INIS)

    Rebuffi, L.

    1987-10-01

    The development and optimization of a microwave technique, concerning the high frequency (electronic cyclotron frequency) plasma heating is presented. The experiments are effectuated on the Fontenay-aux-Roses TFR tokamak, with 660 kw whole power, during 100 msec, produced at 60 GHz. Low power tests are performed on the different transmission line components (there are 3, formed by metallic circular waveguides). The work also includes: the development of a lens formed by thin metallic plans; the study of slotted surface mirror; the development of a system for the accurate measurement (5.10 -6 ) of the gyrotronic frequency; a theory, based on the equivalent circuits method, generalized to the rotational and polarization mirrors; the development of a numerical simulation code. A practical scheme, for the optimization of the parameters concerning the optical transmission line project, is given. The results of this work can be applied to the experiment involving power levels, frequencies and times of impulsion increasingly higher (respectively about MW, 100 GHz and 10s) than the reported ones. Moreover, they can also be used in any experiment in the microwave field [fr

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

    International Nuclear Information System (INIS)

    Olstad, R.A.; Moeller, C.P.; Grunloh, H.J.

    1998-01-01

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

  15. Development of a VMAT quality assurance program

    International Nuclear Information System (INIS)

    Silva, Ricardo Goulart da

    2013-01-01

    Modern radiation therapy keeps evolving and the technological changes include new imaging modalities, new patient immobilization devices and new treatment delivery systems. These advances have made it possible to reduce the dose to normal tissue structures and consequently minimize the risk of toxicity and morbidity, while allowing for dose escalation to the tumor volumes, potentially leading to improved locoregional control. Traditional IMRT techniques offer all of these features but the treatment session time is usually long, mainly for the head and neck cases. Currently, the VMAT technique is a reality in reference centers around the world. This technology has improved delivery efficiency over IMRT, decreasing the treatment application time, as this modality introduces extra degrees of freedom in the optimization process. The modulation of the radiation beams is achieved by simultaneous variation of dynamic parameters such as dose rate, gantry speed and leaves speed. The high level of complexity associated to the new treatment trends, inevitably, requires more accuracy and more rigorous quality assurance programs. The commissioning methods reported for the Varian RapidArc system were extended to an Elekta Synergy linear accelerator, using custom files built in the iComCAT software. Specific tests for the machine quality assurance are presented and also the dosimetric validation process applied to the Monaco treatment planning system. The MLC parameters, modeled by the Monte Carlo algorithm, were analyzed and the TG 119 tests were adapted for VMAT planning. In the end, a specific program developed for the VMAT technology for Elekta accelerators is presented. (author)

  16. Developement of technologies for nuclear fusion at the Karlsruhe Research Center. Pt. 1

    International Nuclear Information System (INIS)

    Bahm, W.; Dammertz, G.; Glugla, M.; Janeschitz, G.; Komarek, P.; Mack, A.

    2002-01-01

    The planned ITER plant needs plasma heating powers of approx. 70-150 MW. Work performed at the Karlsruhe Research Center under this heading mainly comprises the development of microwave oscillators (gyrotrons) and their use for an electron cyclotron resonance heating system and for non-inductive plasma current operation. The plasma, which is approx. 100 million C hot, is confined in a 'magnetic cage' so as to avoid any contact with the wall structures of the vacuum vessel. Building up a magnetic field of this magnitude requires field strengths of at least 2-5 tesla in the plasma; field strengths of 11-13 tesla at the magnet coils are required for future fusion plants, such as ITER. Consequently, the development of the required future superconducting magnet coils enjoys high priority. The blanket, i.e. the enclosure around the combustion chamber of a fusion reactor, plays a major role in the design of a future fusion power plant. Blanket concepts meeting technical requirements are being developed and studied. A blanket must meet three requirements: It must convert the neutron energy into heat, breed the tritium fuel by nuclear reactions, and shield the magnets from neutron and gamma radiations. The fuel cycle of fusion reactors is determined by the gaseous phase of the two hydrogen isotopes, deuterium and tritium. In general, hydrogen handling technologies have been developed to a high level, but can be transferred to the handling of deuterium and radioactive tritium only to a very limited extent. Consequently, the necessary development work is carried out. The state of the plasma, also with respect to its purity, is a factor of special importance, as impurities will cause the plasma to dissolve and thus the fusion reaction to break down. Primary vacuum pumps, another area of activity of the Karlsruhe Research Center, first must evacuate the reactor vessel and then, during operation, maintain the necessary atmosphere. (orig.) [de

  17. Development of an IMRT quality assurance program using an amorphous silicon electronic portal imaging device

    International Nuclear Information System (INIS)

    Hunt, P.; Oliver, L.; Mallik, A.

    2000-01-01

    Full text: Quality Assurance (QA) for an intensity modulated radiotherapy (IMRT) megavoltage beam is a complex task. The positional accuracy of the MLC; its radiation leakage; the overall distribution of the dose delivered as compared to the treatment plan and; the accuracy of the calculated monitor units to deliver this dose, are all important parameters to clinically monitor. We are presently assessing the Varian version 6 software package with CadPlan, Helios with IMRT and inverse planning, VARiS Vision and the linear accelerator DMLC controller. Whilst conventional QA tools such as ionisation chamber and film measurements are used, these methods are inconvenient for directly monitoring an IMRT patient treatment. Varian Medical Systems has developed an improved electronic portal imaging device (EPID) with an amorphous silicon (a-Si) detector array. The A-Si has a sensitive area of 40x30cm and an improved image resolution of 512x384 pixels. Images are recorded at approximately 7-10 frames per second for an exposure rate of 100-600 MU/minute. Although the A-Si was designed as an EPID for a static treatment field, this new device could be a valuable IMRT QA tool for a range of different tests. Measurements taken on the RNSH and Varian prototype A-Si EPI devices showed a linear dose response for 6-18MeV X-ray energy. In addition to the Varian IAS2 internal software handlers, we have developed some image data handling programs to view and analyse these images in more detail. The software is primarily used to view the images; measure the reading in a region of interest or profile; or merge, overlay, add or subtract images during the analysis. The small pixel resolution provides a reliable, highly accurate means of measuring beam size, leaf position, MLC radiation leakage or profile intensity curves with a positional accuracy of 0.8mm. The images produced by an IMRT exposure is clearly discernible and appears consistent with the result expected. Step wedge images

  18. ECRH transmission system

    International Nuclear Information System (INIS)

    Tancredi, J.

    1983-01-01

    Hughes, Electron Dynamics Division is developing gyrotrons for ECRH requirements. In the development program, techniques have been evolved for transmission system components. These techniques include over-moded waveguide tapers, high average power windows, and rf water loads for testing

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

    International Nuclear Information System (INIS)

    Thumm, M.

    1995-04-01

    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 P out =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 P out =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, P out =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: P out =2 GW, τ=20 ns, η=13% at 140 GHz (LLNL) and P out =15 kW, τ=20 μs, η=5% in the range from 120 to 900 GHz (UCSB). (orig.) [de

  20. State-of-the-art of high power gyro-devices and free electron masers. Update 2015

    Energy Technology Data Exchange (ETDEWEB)

    Thumm, Manfred [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Hochleistungsimpuls- und Mikrowellentechnik, Programm Fusion

    2016-07-01

    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 KIT-CRPP-TED collaboration). The world record parameters of the European megawatt-class 140 GHz gyrotron are: 0.92 MW output power at 30 min. pulse duration, 97.5% Gaussian mode purity and 44% efficiency, employing a single-stage depressed collector (SDC) for energy recovery. A maximum output power of 1.5 MW in 4.0 s pulses at 45% efficiency was generated with the JAEA-TOSHIBA 110 GHz gyrotron. The Japan 170 GHz ITER gyrotron achieved 1 MW, 800 s at 55% efficiency and holds the energy world record of 2.88 GJ (0.8 MW, 60 min.) and the efficiency record of 57% for tubes with an output power of more than 0.5 MW. The Russian 170 GHz ITER gyrotron achieved 0.99 (1.2) MW with a pulse duration of 1000 (100) s and 53 (53) % efficiency. The prototype tube of the European 2 MW, 170 GHz coaxial-cavity gyrotron achieved in short pulses the record power of 2.1 MW at 46% efficiency and 96% Gaussian mode purity. Gyrotrons with pulsed magnet for various short-pulse applications deliver P{sub out}=210 kW with τ=20 μs at frequencies up to 670 GHz (η≅20%), P{sub out}=5.3 kW at 1 THz (η=6.1%), and P{sub out}=0.5 kW at 1.3 THz (η=0.6%). Gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: f ≥ 24 GHz, P{sub out}=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

  1. Operational upgrades to the DIII-D 60 GHz electron cyclotron resonant heating system

    International Nuclear Information System (INIS)

    Harris, T.E.; Cary, W.P.

    1993-10-01

    One of the primary components of the DIII-D radio frequency (rf) program over the past seven years has been the 60 GHz electron cyclotron resonant heating (ECRH) system. The system now consists of eight units capable of operating and controlling eight Varian VGE-8006 60 GHz, 200 kW gyrotrons along with their associated waveguide components. This paper will discuss the operational upgrades and the overall system performance. Many modifications were instituted to enhance the system operation and performance. Modifications discussed in this paper include an improved gyrotron tube-fault response network, a computer controlled pulse-timing and sequencing system, and an improved high-voltage power supply control interface. The discussion on overall system performance will include operating techniques used to improve system operations and reliability. The techniques discussed apply to system start-up procedures, operating the system in a conditioning mode, and operating the system during DIII-D plasma operations

  2. Wills Plasma Physics Department annual progress report 1987

    International Nuclear Information System (INIS)

    1988-01-01

    The experimental research program has three major themes - the study of hydromagnetic waves and RF heating using the TORTUS tokamak, the development of diagnostic techniques particularly those based on submillimetre lasers and the gyrotron, and gas discharge studies

  3. Conference Digest - International Conference on Infrared and Millimeter Waves (13th) Held in Honolulu, Hawaii on 5-9 December 1988. Volume 1039.

    Science.gov (United States)

    1989-12-09

    BY MICROSTRIP LINES - ERTIES OF GLASSES AND THE ENERGY TRANSFER TiROUGH S.T. Peng, NY Inst of Technology, Old Westbury, NY 11568; R.T. WINDOWS - R...Power is available from a Varian gyrotron oscillator design is an all-copper machined grating. The polarization in the TEo2 mode in 6.35-cm-diam...dielectric waveguide necessary. The Abel-inverted profile is shown in of *59 mm (Pyrex glass ). The laser beam is divided Fig.3(b). The measured density profile

  4. Large power electron tubes for high frequency heating

    International Nuclear Information System (INIS)

    Okamoto, Tadashi; Sato, Hisaaki.

    1988-01-01

    On the large power electron tubes used for electron cyclotron heating, lower hybrid resonance frequency heating, and ion cyclotron range of frequency heating, namely gyrotron, klystron and quadrupole tube, the features, the present status of development, the construction, the principle and so on are explained. The research and development of gyrotrons are most advanced in USSR, the inventor. The course of the development of gyrotrons in foreign countries and in Japan is described. There are many variants of gyrotrons, for example whispering gallery mode, klystron type, backward wave oscillator type, gyro-peniotron and others. The principle of gyrotrons is explained, and about the examples of the developed gyrotrons, the design parameters are shown. For the purpose of using for the LHRF heating in JT-60, a superlarge power klystron of 1 MW output at 2 GHz frequency, which is the largest class in the world, has been developed. Its total length is 2.7 m, and weight is 1.5 t. It features, construction, function and performance are reported. The trend of large power quadrupole tubes is toward stable action with large power in VHF zone, and the typical products in USA and Europe are shown. (Kako, I.)

  5. Verifikasi Dua Varian Protokol Ad hoc On demand Distance Vector dengan UPPAAL

    Directory of Open Access Journals (Sweden)

    Ika Oktavia Suzanti

    2015-01-01

    Abstract  MANET is a group of wireless mobile that connected one to each other without fixed infrastructure so topology could change at anytime. MANET routing protocol has two models which are reactive routing protocol that built routing table only when needed and proactive routing protocol that maintain routing table periodically. General property which had to be satisfied by ad-hoc network protocol are route discovery, packet delivery and loop freedom. AODV is a reactive protocol in MANET that has time standard to determine how long a route is valid to be used (route validity so route discovery and packet delivery property should be satisfied in a specifically certain time. Protocol verification process done by modeling protocol specification using technique, tool and mathematic language. In this research protocol modeled using timed automata which is a modeling language that could be used to model a time dependent system in each process. Verification using timed automata can automatically done by UPPAAL tool model checker. Protocol which will be verified are AODV Break Avoidance by Ali Khosrozadeh et al. and AODV Reliable Delivery by Liu Jian and Fang-Min. Result of this protocol verification prove that AODV BA could satisfied route discovery property and AODV Reliable Delivery could satisfied packet delivery property within their specification time.   Keywords—Protocol Verification, Timed Automata, AODV, UPPAAL

  6. Dose delivered from Varian's CBCT to patients receiving IMRT for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wen Ning; Guan Huaiqun; Hammoud, Rabih; Pradhan, Deepak; Nurushev, T; Li Shidong; Movsas, Benjamin [Henry Ford Health System, Detroit, MI (United States)

    2007-04-21

    With the increased use of cone beam CT (CBCT) for daily patient setup, the accumulated dose from CBCT may be significantly higher than that from simulation CT or portal imaging. The objective of this work is to measure the dose from daily pelvic scans with fixed technical settings and collimations. CBCT scans were acquired in half-fan mode using a half bowtie and x-rays were delivered in pulsed-fluoro mode. The skin doses for seven prostate patients were measured on an IRB-approved protocol. TLD capsules were placed on the patient's skin at the central axis of three beams: AP, left lateral (Lt Lat) and right lateral (Rt Lat). To avoid the ring artefacts centred in the prostate, the treatment couch was dropped 3 cm from the patient's tattoo (central axis). The measured AP skin doses ranged 3-6 cGy for 20-33 cm separation. The larger the patient size the less the AP skin dose. Lateral doses did not change much with patient size. The Lt Lat dose was {approx}4.0 cGy, which was {approx}40% higher than the Rt Lat dose of {approx}2.6 cGy. To verify this dose asymmetry, surface doses on an IMRT QA phantom (oval shaped, 30 cm x 20 cm) were measured at the same three sites using TLD capsules with 3 cm table-drop. The dose asymmetry was due to: (1) kV source rotation which always starts from the patient's Lt Lat and ends at Lt Lat. Gantry rotation gets much slower near the end of rotation but dose rate stays constant and (2) 370{sup 0} scan rotation (10{sup 0} scan overlap on the Lt Lat side). In vivo doses were measured inside a Rando pelvic heterogeneous phantom using TLDs. The left hip (femoral head and neck) received the highest doses of {approx}10-11 cGy while the right hip received {approx}6-7 cGy. The surface and in vivo doses were also measured for phantoms at the central-axis setup. The difference was less than {approx}12% to the table-drop setup.

  7. Assessment of beam stability of high energy and low energy Varian medical linear accelerators

    International Nuclear Information System (INIS)

    Jayesh, K.; Mohan, R.; Joshi, R.C.; Ganesh, T.; Hegazy, M.; Oubaye, A.J.; AI Idrisi, Maha

    2008-01-01

    An accurate measurement of the dose delivered to the tumor in external beam radiotherapy is one of the primary responsibilities of a medical physicist. In general, such measurements have been based on the application of a dosimetry protocol and quality assurance procedures. Clinically one must be able to assess the beam quality, flatness and symmetry and variation in the output on daily basis. Flatness and symmetry are the main parameters for determining the pattern of a photon and electron beam produced by linear accelerators. The quality assurance in routine clinical practice of radiotherapy and consequently the treatment-outcome depends definitely on the physical parameters of treatment-delivery. Several recommendations from national and international associations are reported to define the limits for the beam parameters. The review of literature and various reports on quality assurance in radiotherapy show that for flatness, symmetry and output constancy the optimal level of deviation should be within ±3%

  8. Dose delivered from Varian's CBCT to patients receiving IMRT for prostate cancer

    International Nuclear Information System (INIS)

    Wen Ning; Guan Huaiqun; Hammoud, Rabih; Pradhan, Deepak; Nurushev, T; Li Shidong; Movsas, Benjamin

    2007-01-01

    With the increased use of cone beam CT (CBCT) for daily patient setup, the accumulated dose from CBCT may be significantly higher than that from simulation CT or portal imaging. The objective of this work is to measure the dose from daily pelvic scans with fixed technical settings and collimations. CBCT scans were acquired in half-fan mode using a half bowtie and x-rays were delivered in pulsed-fluoro mode. The skin doses for seven prostate patients were measured on an IRB-approved protocol. TLD capsules were placed on the patient's skin at the central axis of three beams: AP, left lateral (Lt Lat) and right lateral (Rt Lat). To avoid the ring artefacts centred in the prostate, the treatment couch was dropped 3 cm from the patient's tattoo (central axis). The measured AP skin doses ranged 3-6 cGy for 20-33 cm separation. The larger the patient size the less the AP skin dose. Lateral doses did not change much with patient size. The Lt Lat dose was ∼4.0 cGy, which was ∼40% higher than the Rt Lat dose of ∼2.6 cGy. To verify this dose asymmetry, surface doses on an IMRT QA phantom (oval shaped, 30 cm x 20 cm) were measured at the same three sites using TLD capsules with 3 cm table-drop. The dose asymmetry was due to: (1) kV source rotation which always starts from the patient's Lt Lat and ends at Lt Lat. Gantry rotation gets much slower near the end of rotation but dose rate stays constant and (2) 370 0 scan rotation (10 0 scan overlap on the Lt Lat side). In vivo doses were measured inside a Rando pelvic heterogeneous phantom using TLDs. The left hip (femoral head and neck) received the highest doses of ∼10-11 cGy while the right hip received ∼6-7 cGy. The surface and in vivo doses were also measured for phantoms at the central-axis setup. The difference was less than ∼12% to the table-drop setup

  9. VARIAN NON-DELESI 9 PASANG BASA DNA MITOKONDRIA MANUSIA SAMPEL FORENSIK BALI

    Directory of Open Access Journals (Sweden)

    Gun Gun Gumilar

    2005-06-01

    Full Text Available One of human mitochondrial DNA (mtDNA variant is a 9 base pairs (bp deletion in the COII/tRNALys intergenic region. In construction mtDNA nomenclature, 9-bp deletion database consist of primary and secondary data is needed, including Bali bombing forensic samples. Here we report a 9-bp non- deletion mtDNA variant from Bali bombing forensic samples to complete primary data. Polymerase Chain Reaction (PCR technique with 2 set primer was used to detect 9-bp deletion. The PCR result was detected by agarose gel electrophoresis, which showed two bands (0.1 and 0.4 kb for non-deletion variant control, and one band (0.4 kb for deletion variant control. If the sample has 9-bp deletion, only one of the primer pairs could amplify a fragment of 0.4 kb. If the sample does not have 9-bp deletion, the other primer pair will amplify a 0.1 kb product. The result showed that none of the 24 samples has 9-bp deletion. These results are contributed to the human mtDNA database and nomenclature construction. Keywords: mtDNA, 9-bp deletion, PCR

  10. Introduction and implementation of the basic treatment equivalent in a varian-based department

    International Nuclear Information System (INIS)

    Herbert, C.E.; Joseph, D.J.; Whittall, D.S.; Wilkinson, S.

    2000-01-01

    The increasing popularity of 3-D planning leads to procedural alterations as both workload and resource utilization increase. Although the complexity of the techniques has increased (as well as the set-up and treatment times), the workload statistics must still include the number of fields treated. It is commonly known that machine statistics of fields treated per day do not accurately represent workload because there are major differences between techniques. A mantle treatment technique and an opposed spine technique both have (statistically) two fields, although the setup requirements and treatment times are very different. A basic treatment equivalent (BTE) formula was reported in early 1999 by Delaney et al. and incorporates a large number of variables inherent in patient treatment. The formula considers different factors that affect overall treatment time, and aims to represent a more accurate treatment time indicator. The aim of introducing the BTE into the Department of Radiation Oncology at Sir Charles Gairdner Hospital was to create a more accurate scheduling system and even out workloads on all treatment units. Therefore the BTE formula was used to assess accuracy of treatment times in order to determine if the values could be relied upon as accurate time indicators. Patients undergoing a variety of treatment techniques were timed for the duration of their treatment procedure, and their treatment times compared to the time estimated using the BTE formula. A few minor alterations were made to the equation for treatment units with multi-leaf collimation (MLC). A trial conducted at Sir Charles Gairdner Hospital found that, using the BTE formula (with a few modifications required for the MLC treatment units), of 60 patients timed for the duration of their set-up and treatment, 85% of values were in the range of ±3 min, and 95% were in the range of ± 5 min of the estimated times. Through the routine use of the BTE equation a more sensitive indication of treatment machine workload can be found. Advantages such as: (i) a more accurate measure of treatment workload (for comparison with other departments) and (ii) increased scheduling accuracy will succeed over the currently accepted system of fields per hour. Copyright (1999) Blackwell Science Pty Ltd

  11. Development of a flattening filter free multiple source model for use as an independent, Monte Carlo, dose calculation, quality assurance tool for clinical trials.

    Science.gov (United States)

    Faught, Austin M; Davidson, Scott E; Popple, Richard; Kry, Stephen F; Etzel, Carol; Ibbott, Geoffrey S; Followill, David S

    2017-09-01

    The Imaging and Radiation Oncology Core-Houston (IROC-H) Quality Assurance Center (formerly the Radiological Physics Center) has reported varying levels of compliance from their anthropomorphic phantom auditing program. IROC-H studies have suggested that one source of disagreement between institution submitted calculated doses and measurement is the accuracy of the institution's treatment planning system dose calculations and heterogeneity corrections used. In order to audit this step of the radiation therapy treatment process, an independent dose calculation tool is needed. Monte Carlo multiple source models for Varian flattening filter free (FFF) 6 MV and FFF 10 MV therapeutic x-ray beams were commissioned based on central axis depth dose data from a 10 × 10 cm 2 field size and dose profiles for a 40 × 40 cm 2 field size. The models were validated against open-field measurements in a water tank for field sizes ranging from 3 × 3 cm 2 to 40 × 40 cm 2 . The models were then benchmarked against IROC-H's anthropomorphic head and neck phantom and lung phantom measurements. Validation results, assessed with a ±2%/2 mm gamma criterion, showed average agreement of 99.9% and 99.0% for central axis depth dose data for FFF 6 MV and FFF 10 MV models, respectively. Dose profile agreement using the same evaluation technique averaged 97.8% and 97.9% for the respective models. Phantom benchmarking comparisons were evaluated with a ±3%/2 mm gamma criterion, and agreement averaged 90.1% and 90.8% for the respective models. Multiple source models for Varian FFF 6 MV and FFF 10 MV beams have been developed, validated, and benchmarked for inclusion in an independent dose calculation quality assurance tool for use in clinical trial audits. © 2017 American Association of Physicists in Medicine.

  12. Development of a computational system based in the code GEANT4 for dosimetric evaluation in radiotherapy

    International Nuclear Information System (INIS)

    Oliveira, Alex Cristovao Holanda de

    2016-01-01

    The incidence of cancer has grown in Brazil, as well as around the world, following the change in the age profile of the population. One of the most important techniques and commonly used in cancer treatment is radiotherapy. Around 60% of new cases of cancer use radiation in at least one phase of treatment. The most used equipment for radiotherapy is a linear accelerator (Linac) which produces electron or X-ray beams in energy range from 5 to 30 MeV. The most appropriate way to irradiate a patient is determined during treatment planning. Currently, treatment planning system (TPS) is the main and the most important tool in the process of planning for radiotherapy. The main objective of this work is to develop a computational system based on the MC code Geant4 for dose evaluations in photon beam radiotherapy. In addition to treatment planning, these dose evaluations can be performed for research and quality control of equipment and TPSs. The computer system, called Quimera, consists of a graphical user interface (qGUI) and three MC applications (qLinacs, qMATphantoms and qNCTphantoms). The qGUI has the function of interface for the MC applications, by creating or editing the input files, running simulations and analyzing the results. The qLinacs is used for modeling and generation of Linac beams (phase space). The qMATphantoms and qNCTphantoms are used for dose calculations in virtual models of physical phantoms and computed tomography (CT) images, respectively. From manufacturer's data, models of a Varian Linac photon beam and a Varian multileaf collimator (MLC) were simulated in the qLinacs. The Linac and MLC modelling were validated using experimental data. qMATphamtoms and qNCTphantoms were validated using IAEA phase spaces. In this first version, the Quimera can be used for research, radiotherapy planning of simple treatments and quality control in photon beam radiotherapy. The MC applications work independent of the qGUI and the qGUI can be used for

  13. New development of advanced superconducting electron cyclotron resonance ion source SECRAL (invited)

    International Nuclear Information System (INIS)

    Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Guo, X. H.; Zhao, H. Y.; Feng, Y. C.; Li, J. Y.; Ma, H. Y.; Ma, B. H.; Wang, H.; Li, X. X.; Xie, D. Z.; Lu, W.; Cao, Y.; Shang, Y.

    2010-01-01

    Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e μA of 129 Xe 43+ , 22 e μA of 209 Bi 41+ , and 1.5 e μA of 209 Bi 50+ . To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e μA of 129 Xe 27+ and 152 e μA of 129 Xe 30+ , although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and 129 Xe 27+ , 78 Kr 19+ , 209 Bi 31+ , and 58 Ni 19+ beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development

  14. Intensity Modulated Radiation Therapy. Development of the technique

    International Nuclear Information System (INIS)

    Rafailovici, L.; Alva, R.; Chiozza, J.; Donato, H.; Falomo, S.; Cardiello, C.; Furia, O.; Martinez, A.; Filomia, M.L.; Sansogne, R.; Arbiser, S.; Dosoretz, B.

    2008-01-01

    Full text: Introduction: Intensity Modulated Radiation Therapy (IMRT) is a result of advances in computer sciences that allowed the development of new technology related to planning and radiation therapy. IMRT was developed to homogenize the dose in the target volumes and decrease the dose in the surrounding healthy tissue. Using a software with high calculation capacity a simultaneous irradiation with different doses in a given volume is achieved. IMRT is based on internal planning. Material and methods: 628 patients were treated with IMRT in prostate lesions, head and neck, breast, thorax, abdomen and brain since August 2008. The software for IMRT is the XIO CMS and the accelerator used is a Varian Clinac 6 / 100. IMRT requires a first simulation, where immobilization systems are selected (mats, thermoplastic masks, among others) and the demarcation of the target structures, healthy tissue and dose prescription by a tattoo. Images of CT / MRI are merged when necessary. Once the system made the treatment optimization, this one is regulated by modulators. These are produced by numerical control machines from digital files produced by software. In a second modulation the planned irradiation is checked and tattoo is carried out according with this. We have a strict process of quality assurance to assess the viability of the plan before its implementation. We use the Map Check it possible to compare the dose on the central axis and the distribution in the whole plane regarding to that generated by the planning system. From 03/2008 the virtual simulation process was implemented integrating the described stages. Results and Conclusions: IMRT is a complex technique. The meticulous planning, implementation of process and quality control allows the use of this technique in a reliable and secure way. With IMRT we achieved a high level of dose conformation, less irradiation of healthy tissue, lower rates of complications and the dose escalation for some tumors. (authors) [es

  15. Development and implementation of a software for assessment of calculations in radiotherapy monitor units

    International Nuclear Information System (INIS)

    Mueller, Marcio Rogerio; Silva, Marco Antonio da; Rodrigues, Laura Natal

    2005-01-01

    Objective: To develop and implement a software based on the manual calculation algorithm for verification of the calculations in radiotherapy monitor units and to establish acceptance levels as a mechanism of quality assurance. Materials and methods: Data were obtained from Clinac 600C and 2100C Varian linear accelerators and the computerized treatment planning system used was CadPlan TM . Results: For the 6 MV beams the acceptance levels for deviations among the calculations of monitor units, divided by treatment area, were the following: breast (0.0%±1.7%), head and neck (1.5%±0.5%), hypophysis (-1.7%±0.5%), pelvis (2.1%±2.1%) and thorax (0.2%±1.3%). For the 15 MV beams the suggested level for pelvis in all the treatment techniques was (3.2%±1.3%). Conclusion: The present data are sufficient to justify the use of the software in the clinical practice as a tool for the quality assurance program. (author)

  16. PXIe based data acquisition and control system for ECRH systems on SST-1 and Aditya tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Jatinkumar J., E-mail: jatin@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar (India); Shukla, B.K.; Rajanbabu, N.; Patel, H.; Dhorajiya, P.; Purohit, D. [Institute for Plasma Research, Bhat, Gandhinagar (India); Mankadiya, K. [Optimized Solutions Pvt. Ltd (India)

    2016-11-15

    Highlights: • Data Aquisition and control system (DAQ). • PXIe hardware–(PXI–PCI bus extension for Instrumention Express). • RHVPS–Regulated High Voltage Power supply. • SST1–Steady state superconducting tokamak. - Abstract: In Steady State Superconducting (SST-1) tokamak, various RF heating sub-systems are used for plasma heating experiments. In SST-1, Two Electron Cyclotron Resonance Heating (ECRH) systems have been installed for pre-ionization, heating and current drive experiments. The 42 GHz gyrotron based ECRH system is installed and in operation with SST-1 plasma experiments. The 82.6 GHz gyrotron delivers 200 kW CW power (1000 s) while the 42 GHz gyrotron delivers 500 kW power for 500 ms duration. Each gyrotron system consists of various auxiliary power supplies, the crowbar unit and the water cooling system. The PXIe (PCI bus extension for Instrumentation Express)bus based DAC (Data Acquisition and Control) system has been designed, developed and under implementation for safe and reliable operation of the gyrotron. The Control and Monitoring Software applications have been developed using NI LabView 2014 software with real time support on windows platform.

  17. PXIe based data acquisition and control system for ECRH systems on SST-1 and Aditya tokamak

    International Nuclear Information System (INIS)

    Patel, Jatinkumar J.; Shukla, B.K.; Rajanbabu, N.; Patel, H.; Dhorajiya, P.; Purohit, D.; Mankadiya, K.

    2016-01-01

    Highlights: • Data Aquisition and control system (DAQ). • PXIe hardware–(PXI–PCI bus extension for Instrumention Express). • RHVPS–Regulated High Voltage Power supply. • SST1–Steady state superconducting tokamak. - Abstract: In Steady State Superconducting (SST-1) tokamak, various RF heating sub-systems are used for plasma heating experiments. In SST-1, Two Electron Cyclotron Resonance Heating (ECRH) systems have been installed for pre-ionization, heating and current drive experiments. The 42 GHz gyrotron based ECRH system is installed and in operation with SST-1 plasma experiments. The 82.6 GHz gyrotron delivers 200 kW CW power (1000 s) while the 42 GHz gyrotron delivers 500 kW power for 500 ms duration. Each gyrotron system consists of various auxiliary power supplies, the crowbar unit and the water cooling system. The PXIe (PCI bus extension for Instrumentation Express)bus based DAC (Data Acquisition and Control) system has been designed, developed and under implementation for safe and reliable operation of the gyrotron. The Control and Monitoring Software applications have been developed using NI LabView 2014 software with real time support on windows platform.

  18. 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.

  19. FY92 Progress Report for the Gyrotron Backward-Wave-Oscillator Experiment

    Science.gov (United States)

    1993-07-01

    C. SAMPLE CABLE CALIBRATION 23 D. ASYST CHANNEL SETUPS 26 E. SAMPLE MAGNET INPUT DATA DECK FOR THE GYRO-BWO 32 F. SAMPLE EGUN INPUT DATA DECK FOR THE...of the first coil of the Helmholtz pair; zero also corresponds to the diode end of the experiment). Another computer code used was the EGUN code (Ref...a short computer program was written to superimpose the two magnetic fields; DC and Helmholtz). An example of an EGUN input data file is included in

  20. Ellipsoidal diffraction grating as output coupler for quasi-optical gyrotrons

    International Nuclear Information System (INIS)

    Hogge, J.P.; Cao, H.; Tran, T.M.; Tran, M.Q.; Paris, P.J.; Kasparek, W.

    1991-01-01

    The use of a diffraction grating arranged in the -1 Littrow mount as an output coupler for a quasi-optical Fabry-Perot resonator at microwave frequencies (100 GHz) was suggested in 1990. A planar grating with curvilinear grooves (in order to match the Littrow condition everywhere on the surface for a given Gaussian beam) gives a power coupling efficiency of 85% which is limited by the depolarization but gave approximately the same global efficiency because of distortion. We report low power tests on an improvement of the second scheme, based on curved grooves on an ellipsoidal surface, which gives a global efficiency of 94%. (author) 3 figs., 3 refs

  1. 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

  2. Derivation of gyrotron's reduced equations and its application on the analysis of resonant cavities

    International Nuclear Information System (INIS)

    Correa, R.A.; Barroso, J.J.; Montes, A.

    1988-05-01

    In this paper, it is presented a derivation of a reduced set of equations for the electron motion, based upon Lorentz equation, where the applicability conditions and approximations employed are clearly indicated. As an example of practical interest, scaling relations are discussed in the analysis of cavities appropriate for high efficiency operation. (author)

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

    Indian Academy of Sciences (India)

    particular quality factor for TE mode at the frequency 42 GHz. The perturbation tech ... frequency 42 GHz. The good agreement ... see its performance before the final assembly of the device. This paper .... theoretical work was found. The results ...

  4. Low power excitation of gyrotron-type modes in cylindrical waveguide using quasi-optical techniques

    International Nuclear Information System (INIS)

    Alexandrov, N.L.; Whaley, D.R.; Tran, M.Q.; Denisov, D.R.

    1995-03-01

    Experimental results of low power excitation of a 118 GHz TE 22,6 rotating mode are presented. A rectangular mode is converted to a TE 22,6 circular waveguide using quasi-optical techniques. A good conversion efficiency is measured and the experimentally observed field intensity profiles show the percentage of unwanted modes to be small. (author) 10 figs., 10 refs

  5. Design of the ITER Electron Cyclotron Heating and Current Drive Waveguide Transmission Line

    Science.gov (United States)

    Bigelow, T. S.; Rasmussen, D. A.; Shapiro, M. A.; Sirigiri, J. R.; Temkin, R. J.; Grunloh, H.; Koliner, J.

    2007-11-01

    The ITER ECH transmission line system is designed to deliver the power, from twenty-four 1 MW 170 GHz gyrotrons and three 1 MW 127.5 GHz gyrotrons, to the equatorial and upper launchers. The performance requirements, initial design of components and layout between the gyrotrons and the launchers is underway. Similar 63.5 mm ID corrugated waveguide systems have been built and installed on several fusion experiments; however, none have operated at the high frequency and long-pulse required for ITER. Prototype components are being tested at low power to estimate ohmic and mode conversion losses. In order to develop and qualify the ITER components prior to procurement of the full set of 24 transmission lines, a 170 GHz high power test of a complete prototype transmission line is planned. Testing of the transmission line at 1-2 MW can be performed with a modest power (˜0.5 MW) tube with a low loss (10-20%) resonant ring configuration. A 140 GHz long pulse, 400 kW gyrotron will be used in the initial tests and a 170 GHz gyrotron will be used when it becomes available. Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725.

  6. Poster — Thur Eve — 30: 4D VMAT dose calculation methodology to investigate the interplay effect: experimental validation using TrueBeam Developer Mode and Gafchromic film

    Energy Technology Data Exchange (ETDEWEB)

    Teke, T; Milette, MP [BC Cancer Agency Centre for the Southern Interior (Canada); Huang, V; Thomas, SD [BC Cancer Agency Fraser Valley Cancer Centre (Canada)

    2014-08-15

    The interplay effect between the tumor motion and the radiation beam modulation during a VMAT treatment delivery alters the delivered dose distribution from the planned one. This work present and validate a method to accurately calculate the dose distribution in 4D taking into account the tumor motion, the field modulation and the treatment starting phase. A QUASAR™ respiratory motion phantom was 4D scanned with motion amplitude of 3 cm and with a 3 second period. A static scan was also acquired with the lung insert and the tumor contained in it centered. A VMAT plan with a 6XFFF beam was created on the averaged CT and delivered on a Varian TrueBeam and the trajectory log file was saved. From the trajectory log file 10 VMAT plans (one for each breathing phase) and a developer mode XML file were created. For the 10 VMAT plans, the tumor motion was modeled by moving the isocentre on the static scan, the plans were re-calculated and summed in the treatment planning system. In the developer mode, the tumor motion was simulated by moving the couch dynamically during the treatment. Gafchromic films were placed in the QUASAR phantom static and irradiated using the developer mode. Different treatment starting phase were investigated (no phase shift, maximum inhalation and maximum exhalation). Calculated and measured isodose lines and profiles are in very good agreement. For each starting phase, the dose distribution exhibit significant differences but are accurately calculated with the methodology presented in this work.

  7. TU-AB-BRD-04: Development of Quality Management Program

    Energy Technology Data Exchange (ETDEWEB)

    Thomadsen, B. [University of Wisconsin (United States)

    2015-06-15

    Current quality assurance and quality management guidelines provided by various professional organizations are prescriptive in nature, focusing principally on performance characteristics of planning and delivery devices. However, published analyses of events in radiation therapy show that most events are often caused by flaws in clinical processes rather than by device failures. This suggests the need for the development of a quality management program that is based on integrated approaches to process and equipment quality assurance. Industrial engineers have developed various risk assessment tools that are used to identify and eliminate potential failures from a system or a process before a failure impacts a customer. These tools include, but are not limited to, process mapping, failure modes and effects analysis, fault tree analysis. Task Group 100 of the American Association of Physicists in Medicine has developed these tools and used them to formulate an example risk-based quality management program for intensity-modulated radiotherapy. This is a prospective risk assessment approach that analyzes potential error pathways inherent in a clinical process and then ranks them according to relative risk, typically before implementation, followed by the design of a new process or modification of the existing process. Appropriate controls are then put in place to ensure that failures are less likely to occur and, if they do, they will more likely be detected before they propagate through the process, compromising treatment outcome and causing harm to the patient. Such a prospective approach forms the basis of the work of Task Group 100 that has recently been approved by the AAPM. This session will be devoted to a discussion of these tools and practical examples of how these tools can be used in a given radiotherapy clinic to develop a risk based quality management program. Learning Objectives: Learn how to design a process map for a radiotherapy process Learn how to

  8. TU-AB-BRD-04: Development of Quality Management Program

    International Nuclear Information System (INIS)

    Thomadsen, B.

    2015-01-01

    Current quality assurance and quality management guidelines provided by various professional organizations are prescriptive in nature, focusing principally on performance characteristics of planning and delivery devices. However, published analyses of events in radiation therapy show that most events are often caused by flaws in clinical processes rather than by device failures. This suggests the need for the development of a quality management program that is based on integrated approaches to process and equipment quality assurance. Industrial engineers have developed various risk assessment tools that are used to identify and eliminate potential failures from a system or a process before a failure impacts a customer. These tools include, but are not limited to, process mapping, failure modes and effects analysis, fault tree analysis. Task Group 100 of the American Association of Physicists in Medicine has developed these tools and used them to formulate an example risk-based quality management program for intensity-modulated radiotherapy. This is a prospective risk assessment approach that analyzes potential error pathways inherent in a clinical process and then ranks them according to relative risk, typically before implementation, followed by the design of a new process or modification of the existing process. Appropriate controls are then put in place to ensure that failures are less likely to occur and, if they do, they will more likely be detected before they propagate through the process, compromising treatment outcome and causing harm to the patient. Such a prospective approach forms the basis of the work of Task Group 100 that has recently been approved by the AAPM. This session will be devoted to a discussion of these tools and practical examples of how these tools can be used in a given radiotherapy clinic to develop a risk based quality management program. Learning Objectives: Learn how to design a process map for a radiotherapy process Learn how to

  9. Estimating effective wedge factor for enhanced dynamic wedge 2100CD a Varian Clinac; Calculo De factor cuna efectiva para cuna dinamica mejorada de un Clinac 2100CD de Varian

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro Trigo, F.; Morillas Ruiz, J.; Nunuz Martinez, L.; Sanchez Jimenez, J.

    2011-07-01

    The purpose of this paper is to compare different methods of calculating the effective factor enhanced dynamic wedge (EDWF) with the values ??obtained in measurements of symmetric and asymmetric fields.

  10. Progress of the 10 MW ECRH System for W7-X

    International Nuclear Information System (INIS)

    Michel, G.; Brand, P.; Dammertz, G.

    2003-01-01

    The electron cyclotron resonance heating system for the W7-X stellarator is a joint effort of the Max-Planck-Institut fuer Plasmaphysik in Greifswald, the Institut fuer Plasmaforschung Stuttgart and the Forschungszentrum Karlsruhe under the supervision of the latter. Currently it is being constructed at the Greifswald branch of IPP. It will consist of 10 gyrotrons (each with 1 MW 140 GHz in the CW regime) and a quasi optical multi-beam transmission line. W7-X gyrotron candidates are being developed separately in Western Europe and the USA. The prototype phase of the gyrotrons is almost over and significant results have been achieved. The manufacturing of the transmission line is ongoing. An overview over the system including data acquisition and control issues will be given and the current status of the construction will be presented. (authors)

  11. The Compact Ignition Tokamak and electron cyclotron heating: Description of need; assessment of prospects

    International Nuclear Information System (INIS)

    Ignat, D.W.; Cohn, D.R.; Woskov, P.P.

    1989-01-01

    The CIT will benefit from auxiliary heating of 10 to 40 MW. The schedules of both the CIT construction project and the operating plan contain adequate time to develop and implement ECH systems based on the gyrotron and the induction free electron laser (IFEL). Each approach has advantages and is the object of R and D at the level of many millions of dollars per year. While the gyrotron is further advanced in terms of power and pulse length achieved, rapid progress is scheduled for the IFEL, including experiments on tokamaks. Plans of CIT, gyrotron, and IFEL make 1992 an appropriate time frame to commit to one or both systems. 12 refs., 8 figs., 2 tabs

  12. Development of a computational system based in the code GEANT4 for dosimetric evaluation in radiotherapy; Desenvolvimento de um sistema computacional baseado no Codigo GEANT4 para avaliacoes dosimetricas em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Alex Cristovao Holanda de

    2016-10-01

    The incidence of cancer has grown in Brazil, as well as around the world, following the change in the age profile of the population. One of the most important techniques and commonly used in cancer treatment is radiotherapy. Around 60% of new cases of cancer use radiation in at least one phase of treatment. The most used equipment for radiotherapy is a linear accelerator (Linac) which produces electron or X-ray beams in energy range from 5 to 30 MeV. The most appropriate way to irradiate a patient is determined during treatment planning. Currently, treatment planning system (TPS) is the main and the most important tool in the process of planning for radiotherapy. The main objective of this work is to develop a computational system based on the MC code Geant4 for dose evaluations in photon beam radiotherapy. In addition to treatment planning, these dose evaluations can be performed for research and quality control of equipment and TPSs. The computer system, called Quimera, consists of a graphical user interface (qGUI) and three MC applications (qLinacs, qMATphantoms and qNCTphantoms). The qGUI has the function of interface for the MC applications, by creating or editing the input files, running simulations and analyzing the results. The qLinacs is used for modeling and generation of Linac beams (phase space). The qMATphantoms and qNCTphantoms are used for dose calculations in virtual models of physical phantoms and computed tomography (CT) images, respectively. From manufacturer's data, models of a Varian Linac photon beam and a Varian multileaf collimator (MLC) were simulated in the qLinacs. The Linac and MLC modelling were validated using experimental data. qMATphamtoms and qNCTphantoms were validated using IAEA phase spaces. In this first version, the Quimera can be used for research, radiotherapy planning of simple treatments and quality control in photon beam radiotherapy. The MC applications work independent of the qGUI and the qGUI can be used for

  13. Kapasitas Antioksidan Ekstrak Buah Salak (Salacca Zalacca (Gaertn.) Voss) Varian Gula Pasir Menggunakan Metode Penangkapan Radikal Dpph

    OpenAIRE

    Puspitasari, Endah; Ningsih, Indah Yulia

    2016-01-01

    The aim of this study was to evaluate antioxidant capacity of gula pasir variant of snake fruit (Salacca zalacca (Gaertn.) Voss) water extract using free radical scavenging activity of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). The inhibition concentration (IC50) sufficient to elicit 50% of a maximum effect estimated in 100% was 40.89±6.35 μg/mL for the DPPH radical scavenging activity. While the positive control, quercetin, had IC50 value of 8.79±0.90 μg/mL. Based on the IC50 value, w...

  14. Studi Analisis Varians Ranking Dua- Arah Friedman terhadap Kompetensi Dimensi Pengetahuan Auditor di Kantor Akuntan Publik Jakarta

    OpenAIRE

    Ratnawati, Ratnawati; Samosir, Perak

    2012-01-01

    In conducting the auditing, the auditor should have the competence dimension of knowledge. It can be analyzed through therespondent's answers to the statements relating to the competence dimension of knowledge of an auditor. The purpose of this studyis to see if there is a statement to the effect of the respondent's answer and whether there is a correlation between the grain statements.The method used analysis of auditor competence dimension of knowledge in performing auditing and other data ...

  15. A model to generate beam profiles of the Varian Clinac 4 for three-dimensional dose calculation: open fields

    International Nuclear Information System (INIS)

    Lam, K.S.; Lam, W.C.

    1984-01-01

    For the Clinac 4, open field profiles measured in the principal plane have higher intensity ''horns'' than those in off-axis planes. The maximum deviation occurs at 1-cm depth, where in the worst case of large field sizes and off-axis distances the deviation can be as high as 16% in the region near the horns. A model is proposed to generate open field beam profiles in off-axis planes, based on measured profiles in the transverse principal plane and in the largest field size diagonal plane of the machine. Within the central 90% portion of the field, the maximum deviation of the generated profiles from the measured ones at the same off-axis distance varies from about 3% at 1-cm depth to about 2% at 13-cm depth and then increases to less than 5% at 25-cm depth, even for very large field sizes and off-axis distances. Very little additional computer time and data storage are required for this procedure. Using these profiles, the Milan and Bentley method can be extended to three-dimensional treatment planning with good accuracy

  16. An improved Monte-Carlo model of the Varian EPID separating support arm and rear-housing backscatter

    International Nuclear Information System (INIS)

    Monville, M E; Greer, P B; Kuncic, Z

    2014-01-01

    Previous investigators of EPID dosimetric properties have ascribed the backscatter, that contaminates dosimetric EPID images, to its supporting arm. Accordingly, Monte-Carlo (MC) EPID models have approximated the backscatter signal from the layers under the detector and the robotic support arm using either uniform or non-uniform solid water slabs, or through convolutions with back-scatter kernels. The aim of this work is to improve the existent MC models by measuring and modelling the separate backscatter contributions of the robotic arm and the rear plastic housing of the EPID. The EPID plastic housing is non-uniform with a 11.9 cm wide indented section that runs across the cross-plane direction in the superior half of the EPID which is 1.75 cm closer to the EPID sensitive layer than the rest of the housing. The thickness of the plastic housing is 0.5 cm. Experiments were performed with and without the housing present by removing all components of the EPID from the housing. The robotic support arm was not present for these measurements. A MC model of the linear accelerator and the EPID was modified to include the rear-housing indentation and results compared to the measurement. The rear housing was found to contribute a maximum of 3% additional signal. The rear housing contribution to the image is non-uniform in the in-plane direction with 2% asymmetry across the central 20 cm of an image irradiating the entire detector. The MC model was able to reproduce this non-uniform contribution. The EPID rear housing contributes a non-uniform backscatter component to the EPID image, which has not been previously characterized. This has been incorporated into an improved MC model of the EPID.

  17. Annual report on major results and progress of Fusion Research and Development Directorate of JAEA from April 1, 2006 to March 31, 2007

    International Nuclear Information System (INIS)

    Suzuki, Satoshi; Ishii, Yasutomo; Sukegawa, Atsuhiko; Iwai, Yasunori; Nakamura, Hiroo; Sugie, Tatsuo

    2008-08-01

    This annual report provides an overview of major results and progress on research and development (R and D) activities at Fusion Research and Development Directorate of Japan Atomic Energy Agency (JAEA) from April 1, 2006 to March 31, 2007, including those performed in collaboration with other research establishments of JAEA, research institutes, and universities. In JT-60, as a result of ferritic steel tiles (FSTs) installation to reduce the toroidal field ripple and the application of the real time current profile control, high boot strap current fraction (∼0.7) has successfully been sustained about 8 s. In addition, the conceptual design of JT-60SA, which was placed as a combined project of JA-EU Satellite Tokamak Programme under the Broader Approach Programme and JAEA's programme for national use, was progressed. In theoretical and analytical researches, studies on ITB events and their triggers, plasma shape effect on edge stability and driven magnetic island evolution in rotating plasmas were progressed. In the NEXT project, computer simulations of the plasma turbulence were progressed. In fusion reactor technologies, R and Ds for ITER and fusion DEMO plants have been carried out. For ITER, a steady state operation of the 170GHz gyrotron up to 10min with 0.82MW was demonstrated. Also current density of the neutral beam injector has been extended to 146A/m 2 at 0.84MeV. In the ITER Test Blanket Module (TBM), designs and R and Ds of Water and Helium Cooled Solid Breeder TBMs including tritium breeder/multiplier materials were progressed. Tritium processing technology for breeding blankets and neutronics integral experiments with a blanket mockup were also progressed. For ITER and DEMO blankets, studies on neutron irradiation effects and ion irradiation effects on F82H steel characteristics were continued using HFIR, TIARA and so on. In the IFMIF program, transitional activities to EVEDA were continued. In the ITER Program, under the framework of the ITER

  18. Development and Validation of a Rapid RP-HPLC Method for the Determination of Venlafaxine Hydrochloride in Pharmaceutical Dosage forms using Experimental Design

    Directory of Open Access Journals (Sweden)

    Vanita Somasekhar

    2009-01-01

    Full Text Available The objective of the current study was to develop a simple, accurate, precise and rapid reversed-phase HPLC method and subsequent validation as per ICH guidelines for the determination of venlafaxine hydrochloride in pharmaceutical dosage forms. The proposed RP-HPLC method utilizes a 5 μm Varian® Microsorb-MV 100 C18 column (250 mmx4.6 mm at ambient temperature. A 23 factorial design consisting of 3 factors at 2 levels was set up to standardize the chromatographic conditions. A numerical optimization technique employing the desirability approach was used to locate the optimum chromatographic conditions. The optimum mobile phase consisted of acetonitrile, 0.04 M potassium dihydrogen phosphate buffer and methanol (45:25:30, v/v, with pH adjusted to 5.5 using 10% phosphoric acid solution. The mobile phase was delivered isocratically at a flow rate of 1 mL/min with UV detection at 224 nm. The calibration plots constructed using the optimized chromatographic conditions displayed good linear relationship in the concentration range of 1-50 μg/mL with r=0.9992. The method was validated for precision, accuracy, robustness and recovery. The minimum detectable and minimum quantifiable amounts were found to be 0.568 and 1.72 μg/mL, respectively and the method was found to be reproducible from the statistical data generated. Venlafaxine hydrochloride was eluted at 3.43 min

  19. Brain Development

    Science.gov (United States)

    ... Become a Member Home Early Development & Well-Being Brain Development A child’s brain undergoes an amazing period of development from birth ... neural connections each second. The development of the brain is influenced by many factors, including a child’s ...

  20. Recent developments on the 110 GHz electron cyclotron installation on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Ponce, D.; Callis, R.W.; Cary, W.P.; Ferron, J.R.; Green, M.; Grunloh, H.J.; Gorelov, Y.; Lohr, J.; Ellis, R.A.

    2003-01-01

    Significant improvements are being implemented to the capability of the 110 GHz electron cyclotron system on the DIII-D tokamak. Chief among these is the addition of the fifth and sixth 1 MW class gyrotrons, increasing the power available for auxiliary heating and current drive by nearly 60%. These tubes use artificially grown diamond r.f. output windows to obtain high power with long pulse capability. The beams from these tubes are nearly Gaussian, facilitating coupling to the waveguide. A new fully articulating dual launcher capable of high speed spatial scanning has been designed and tested. The launcher has two axis independent steering for each waveguide. The mirrors can be rotated at up to 100 deg./s. A new feedback system linking the DIII-D Plasma Control System (PCS) with the gyrotron beam voltage waveform generators permits real-time feedback control of some plasma properties such as electron temperature. The PCS can use a variety of plasma monitors to generate its control signal, including electron cyclotron emission and Mirnov probes. Electron cyclotron heating and electron cyclotron current drive were used during this year's DIII-D experimental campaign to control electron temperature, density, and q profiles, induce an ELM-free H-mode, and suppress the m=2/n=1 neoclassical tearing mode. The new capabilities have expanded the role of EC systems in tokamak plasma control

  1. Employees development

    OpenAIRE

    Kilijánová, Radka

    2010-01-01

    Employees development is one of the main activities of human resources management. It is connected with other activites, such as training of employees, career development and performance management. In the recent days there is an increased importance put on employees development, although the current economic crisis still has some consequences, such as reduced development budget of many organizations. The thesis mentiones employees development in the first place in the context of management o...

  2. 110GHz ECH on DIII-D

    International Nuclear Information System (INIS)

    Cary, W.P.; Allen, J.C.; Callis, R.W.; Doane, J.L.; Harris, T.E.; Moetler, C.P.; Neren, A.; Prater, P.; Rensen, D.

    1992-01-01

    This paper reports on a new high power electron cyclotron heating (ECH) system which has been introduced on DIII-D. This system is designed to operate at 110 GHz with a total output power of 2 MW. The system consists of four Varian VGT-8011 gyrotrons (output power of 500 kW), and their associated support equipment. All components have been designed for up to a 10 second pulse duration. The 110 GHz system is intended to further progress in rf current drive experiments on DIII-D when used in conjunction with the existing 60 GHz ECH (1. 6 MW) , and the 30-60 MHz ICH (2MW) systems. H-mode physics, plasma stabilization experiments and transport studies are also to be conducted at 110 GHz

  3. Multimobile Development

    CERN Document Server

    Baxter-Reynolds, Matthew

    2010-01-01

    You've developed a killer app for one mobile device - now it's time to maximize your intellectual investment and develop for the full spectrum of mobile platforms and devices. With Multimobile Development, you'll learn how to quickly retool between the iPhone and Android platforms and broaden the interest and audience of your app, without working with burdensome and error-prone compatibility layers and toolkits. Multimobile Development takes you, the developer, through the same mobile software development project on both platforms, learning the differences between and the relative strengths an

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

    International Nuclear Information System (INIS)

    Callis, R.W.

    1997-08-01

    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

  5. Representing Development

    DEFF Research Database (Denmark)

    Representing Development presents the different social representations that have formed the idea of development in Western thinking over the past three centuries. Offering an acute perspective on the current state of developmental science and providing constructive insights into future pathways, ...

  6. Economic Development

    Science.gov (United States)

    Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded : Environmental Documents, Reports LANL Home Calendar Search Contacts Community » Economic Development LANL 75th logo Economic Development Los Alamos National Laboratory is committed to investing and partnering in

  7. Modularizing development

    DEFF Research Database (Denmark)

    Müller, Anders Riel; Doucette, Jamie

    a deeper and wider understanding of Korea’s development experience with the hope that Korea’s past can offer lessons for developing countries in search of sustainable and broad‐based development" (KSP 2011). To do so, the KSP provides users with a modularized set of policy narratives that represent Korea...

  8. SU-F-BRB-16: A Spreadsheet Based Automatic Trajectory GEnerator (SAGE): An Open Source Tool for Automatic Creation of TrueBeam Developer Mode Robotic Trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Etmektzoglou, A; Mishra, P; Svatos, M [Varian Medical Systems, Palo Alto, CA (United States)

    2015-06-15

    translate research ideas into machine readable scripts without programming knowledge. As an open source initiative, it also enables researcher collaboration on future developments. I am a full time employee at Varian Medical Systems, Palo Alto, California.

  9. SU-F-BRB-16: A Spreadsheet Based Automatic Trajectory GEnerator (SAGE): An Open Source Tool for Automatic Creation of TrueBeam Developer Mode Robotic Trajectories

    International Nuclear Information System (INIS)

    Etmektzoglou, A; Mishra, P; Svatos, M

    2015-01-01

    translate research ideas into machine readable scripts without programming knowledge. As an open source initiative, it also enables researcher collaboration on future developments. I am a full time employee at Varian Medical Systems, Palo Alto, California

  10. Developing Collaborative Product Development Capabilities

    DEFF Research Database (Denmark)

    Mahnke, Volker; Tran, Yen

    2012-01-01

    innovation strategies’. Our analyses suggest that developing such collaboration capabilities benefits from the search for complementary practices, the combination of learning styles, and the development of weak and strong ties. Results also underscore the crucial importance of co-evolution of multi......Collaborative product development capabilities support a company’s product innovation activities. In the context of the fast fashion sector, this paper examines the development of the product development capabilities (PDC) that align product development capabilities in a dual innovation context......, one, slow paced, where the firm is well established and the other, fast paced, which represents a new competitive arena in which the company competes. To understand the process associated with collaborative capability development, we studied three Scandinavian fashion companies pursuing ‘dual...

  11. 1990's annual report of INPE's Plasma Associated Laboratory

    International Nuclear Information System (INIS)

    1991-06-01

    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.)

  12. 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

    A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclot...

  13. Numerical Development

    Science.gov (United States)

    Siegler, Robert S.; Braithwaite, David W.

    2016-01-01

    In this review, we attempt to integrate two crucial aspects of numerical development: learning the magnitudes of individual numbers and learning arithmetic. Numerical magnitude development involves gaining increasingly precise knowledge of increasing ranges and types of numbers: from non-symbolic to small symbolic numbers, from smaller to larger…

  14. Child Development

    Science.gov (United States)

    ... developmental conditions. More Child Development Basics Early Brain Development Developmental Screening Screening for Professionals Positive Parenting Tips Infants (0-1 year) Toddlers (1-2 years) Toddlers (2-3 years) Preschoolers (3-5 years) Middle Childhood (6-8 years) Middle Childhood (9-11 years) ...

  15. Stamen development

    NARCIS (Netherlands)

    Keijzer, C.J.

    1986-01-01

    In this thesis the development of the stamen is investigated, using structural and histochemical observations, micromanipulation and in-vitro culture.

    Formation and exposure of pollen are the two main goals of the developing stamen. The main processes of the pollen formation were

  16. Africa Development

    African Journals Online (AJOL)

    Africa Development is the quarterly bilingual journal of CODESRIA. It is a social science journal whose major focus is on issues which are central to the development of society. Its principal objective is to provide a forum for the exchange of ideas among African scholars from a variety of intellectual persuasions and various ...

  17. Photocathode development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of photocathodes for use in streak image tubes is described. This is one task in the development of a high-resolution, high-speed x-ray streak camera system whose primary application is for diagnostics in underground nuclear testing. There are three objectives in the photocathode development program: (1) the development of new x-ray photocathodes compatible with the requirements of streak tubes; (2) the development of the capability to process high-quality visible light photocathodes as well as x-ray photocathodes; and (3) the design and construction of a transfer photocathode system. Design and construction of all the major components of the transfer photocathode system were completed. Assembly should be completed in early FY 80

  18. Developing markets?

    DEFF Research Database (Denmark)

    Figueiredo, Bernardo; Chelekis, Jessica; DeBerry-Spence, Benet

    2015-01-01

    acknowledging complex, systemic interdependencies between markets, marketing, and society. Based on a critical review of the meaning of development and an interrogation of various developmental discourses, the authors develop a conceptual framework that brings together issues of development, wellbeing......, and social inequalities. We suggest that these issues are better understooda nd addressed when examined via grounded investigations of the role of markets in shaping the management of resources, consumer agency, power inequalities and ethics. The use of markets as units of analysis may lead to further cross...

  19. Developing Friendships:

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    2005-01-01

    reparations and - to a lesser degree - ODA as repentance for war crimes. Officials and other invlved parties often coded their interventions of development projects in language of friendship, whereby they expressed a Japanese desire to change the image of Japan from enemy to friend. In the wake of WWII...... of these programs in development assistance initiatives reflected Japanese attempts to redefine themselves as friends rather than enemies in the minds of Asian neighbors. Other donors also used friendship vocabulary in relation to their development assistance and I will apply a comparative perspective in order...

  20. Development and implementation of a software for assessment of calculations in radiotherapy monitor units; Elaboracao e implementacao de um programa para verificacao dos calculos das unidades monitoras em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Marcio Rogerio; Silva, Marco Antonio da; Rodrigues, Laura Natal [Sao Paulo Univ., SP (Brazil). Hospital das Clinicas. Servico de Radioterapia]. E-mail: mrmuller@usp.br

    2005-12-01

    Objective: To develop and implement a software based on the manual calculation algorithm for verification of the calculations in radiotherapy monitor units and to establish acceptance levels as a mechanism of quality assurance. Materials and methods: Data were obtained from Clinac 600C and 2100C Varian linear accelerators and the computerized treatment planning system used was CadPlan{sup TM}. Results: For the 6 MV beams the acceptance levels for deviations among the calculations of monitor units, divided by treatment area, were the following: breast (0.0%{+-}1.7%), head and neck (1.5%{+-}0.5%), hypophysis (-1.7%{+-}0.5%), pelvis (2.1%{+-}2.1%) and thorax (0.2%{+-}1.3%). For the 15 MV beams the suggested level for pelvis in all the treatment techniques was (3.2%{+-}1.3%). Conclusion: The present data are sufficient to justify the use of the software in the clinical practice as a tool for the quality assurance program. (author)

  1. Organisational development.

    Science.gov (United States)

    2017-03-30

    The aim of the NHS Improvement national leadership and improvement strategy is to encourage leaders at all levels to develop leadership skills in their staff and themselves. It focuses on fostering compassionate, collaborative and inclusive leadership.

  2. Personality Development

    Directory of Open Access Journals (Sweden)

    Osman Ozdemir

    2012-12-01

    Full Text Available Personality is the integration of characteristics acquired or brought by birth which separate the individual from others. Personality involves aspects of the individual's mental, emotional, social, and physical features in continuum. Several theories were suggested to explain developmental processes of personality. Each theory concentrates on one feature of human development as the focal point, then integrates with other areas of development in general. Most theories assume that childhood, especially up to 5-6 years, has essential influence on development of personality. The interaction between genetic and environmental factors reveals a unique personality along growth and developmental process. It could be said that individual who does not have any conflict between his/her basic needs and society's, has well-developed and psychologically healthy personality.

  3. Toddler Development

    Science.gov (United States)

    ... is exciting to watch your toddler learn new skills. The normal development of children aged 1-3 includes several areas: Gross motor - walking, running, climbing Fine motor - feeding themselves, drawing Sensory - seeing, hearing, tasting, ...

  4. Untenable development

    International Nuclear Information System (INIS)

    Coimbra, Guilhermina Lavoz

    1995-01-01

    The author analyses the energy - the role of law and environmental rights for sustainable development - from a critical point of view that is in accordance with internationally accepted jurisprudence. (author). 12 refs

  5. Toddler development

    Science.gov (United States)

    ... a secure place. Keep toddlers away from the kitchen with a safety gate. Place them in a ... development. In: Marcdante KJ, Kliegman RM, eds. Nelson Essentials of Pediatrics . 7th ed. Elsevier Saunders; 2015:chap ...

  6. Site development

    International Nuclear Information System (INIS)

    Noack, J.

    1975-01-01

    The subject of this paper is a general view over all necessary considerations to develop the site after it has been chosen and before starting with the construction of a nuclear power plant. (orig./RW) [de

  7. Professional development

    International Nuclear Information System (INIS)

    McAndrew-Benavidas, E.

    2007-01-01

    This presentation outlines the functions of the North American Young Generation in Nuclear. Activities of the organization include professional development, recruiting, retention, public outreach, leadership, networking, workforce issues, mentoring and communications

  8. Adolescent development

    Science.gov (United States)

    ... to: Understand abstract ideas. These include grasping higher math concepts, and developing moral philosophies, including rights and ... of safe play and how to approach more advanced activities. Young people need to be very aware ...

  9. Toddler development.

    Science.gov (United States)

    Colson, E R; Dworkin, P H

    1997-08-01

    The toddler years are ones of exciting and challenging changes in cognitive, affective, and physical growth. Physical growth is particularly remarkable for the child's increasing skills and ability to navigate the environment. Affective development is marked by the push for autonomy and independence and the highly visible nature of the child's temperament or behavioral style. The toddler also enters the wonderful years of imagination and pretend play. Perhaps most noteworthy is the child's dramatic increase in ability to communicate with others through speech and language, as evidence of the progression to symbolic thinking. The dynamic changes in children's development during the toddler years have important implications for child health supervision. Familiarity with toddler development will enable the pediatrician to monitor children's development effectively and to address common, stage-related behaviors with families during anticipatory guidance.

  10. Recent Developments

    CERN Multimedia

    Lankford, A J

    Progress has proceeded rapidly on many parallel developments throughout the Trigger, Data Acquisition, and Detector Controls Project. As design has proceeded on the component TDAQ/DCS systems and subsystems, significant integration tests have been performed. Late last year and early this year, high level trigger and data acquisition developments were brought together in what we called the Phase 1 integrated prototype. During the same period, work was started on integrating the Detector Control System (DCS) with the Online Software that will be used to control, configure, and monitor ATLAS. In addition, integration tests between components of the Level 1 Trigger (LVL1) and Dataflow systems have been performed. The Phase 1 integrated prototype involved integrating the prototype level 2 trigger system (LVL2) developed by the LVL2 Pilot Project with the prototype data acquisition system and one of the Event Filter prototypes developed by the DAQ/EF -1 Prototype project. The integrated prototype included a VME Re...

  11. Process development

    Energy Technology Data Exchange (ETDEWEB)

    Schuegerl, K

    1984-01-01

    The item 'process development' comprises the production of acetonic/butonal with C. acetobylicum and the yeasting of potato waste. The target is to increase productivity by taking the following measures - optimation of media, on-line process analysis, analysis of reaction, mathematic modelling and identification of parameters, process simulation, development of a state estimator with the help of the on-line process analysis and the model, optimization and adaptive control.

  12. Instrumentation development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Areas being investigated for instrumentation improvement during low-level pollution monitoring include laser opto-acoustic spectroscopy, x-ray fluorescence spectroscopy, optical fluorescence spectroscopy, liquid crystal gas detectors, advanced forms of atomic absorption spectroscopy, electro-analytical chemistry, and mass spectroscopy. Emphasis is also directed toward development of physical methods, as opposed to conventional chemical analysis techniques for monitoring these trace amounts of pollution related to energy development and utilization

  13. Future development

    International Nuclear Information System (INIS)

    Zavitz, J.; Hetherington, C.

    1997-01-01

    Issues regarding future development by oil and gas companies in Canada's Arctic and the Beaufort Sea were discussed. It was suggested in the Berger report that Northern development should be under the control of the people whose lives and economy are being changed. Aboriginal people are now much more sophisticated politically, and have a better understanding of what is involved. Most of them would like the financial benefits from development, but the development would have to be on their terms. Most people involved with Arctic oil exploration feel that there is enough oil in the Arctic to warrant production. (Reserves in the Beaufort Sea are estimated at two billion barrels of good quality oil). If development were to continue, there exist two methods of transportation to move the oil to market. Gulf, Imperial Oil and Panarctic favour the use of pipelines, whereas Dome Petroleum Ltd. favours the use of ice-breaking tankers. In each case the favored option seems to depend upon the location of the company's leases, the capital and operating costs, and the potential environmental impacts. Undoubtedly, any future development will be guided by the scientific information and technical expertise of oil industry pioneers of the 1960s and the 1970s, and the wisdom gained from the experiences of the many participants whose views and insights are recorded in this book

  14. Annual report of Fusion Research and Development Directorate of JAEA

    International Nuclear Information System (INIS)

    Kubo, Hirotaka; Hoshino, Katsumichi; Isei, Nobuaki; Nakamura, Hiroo; Sato, Satoshi; Shimada, Katsuhiro; Sugie, Tatsuo

    2009-01-01

    This annual report provides an overview of major results and progress on research and development (R and D) activities at Fusion Research and Development Directorate of Japan Atomic Energy Agency (JAEA) from April 1, 2007 to March 31, 2008, including those performed in collaboration with other directorates of JAEA, research institutes, and universities. The JT-60U operation regime was extended toward the long sustainment of high normalized beta (β N ) with good confinement (β N =2.6 x 28 s). Effectiveness of real-time control of current profile was demonstrated in high β plasmas. Toroidal momentum diffusivity and the convection velocity were systematically clarified for the first time, and intrinsic rotation due to pressure gradient was discovered. Effects of toroidal rotation and magnetic field ripple on type 1 ELM size and pedestal performance were clarified, and type I ELM control was demonstrated by toroidal rotation control. Variety of inter-machine experiments, such as JT-60U and JET, and domestic collaborations were performed. In theoretical and analytical researches, for the NEXT (Numerical Experiment of Tokamak) project, numerical simulations of a tokamak plasma turbulence progressed and a zonal field generation was investigated. Also, nonlinear MHD simulations found the Alfven resonance effects on the evolution of magnetic islands driven by externally applied perturbations. Integrations of several kinds of element codes progressed in the integrated transport/MHD model, the integrated edge/pedestal model and the integrated SOL/divertor model. In fusion reactor technologies, R and Ds for ITER and fusion DEMO plants have been carried out. For ITER, a steady state operation of the 170GHz gyrotron up to 800 s with 1 MW was demonstrated. Also extracted beam current of the neutral beam injector has been extended to 320 mA at 796 keV. In the ITER Test Blanket Module (TBM), designs and R and Ds on Water and Helium Cooled Solid Breeder TBMs were progressed. For

  15. Site development

    International Nuclear Information System (INIS)

    Gaynor, R.K.

    1989-01-01

    Development of a low-level radioactive waste land disposal facility is little different than any industrial development of similar scope. Consideration must be made for normal business and operations management, security, facility maintenance, traffic control and necessary amenities for personnel. The item specific to the low-level waste site is the handling of radioactive waste materials and the regulatory and environmental protection procedures that must be planned for and accomodated in the site design and development. Each of these elements and the facility as a whole must be designed to be compatible with local land use plans, available transportation and support services, and the social and economic goals of the local community. Plans should also be made for quality control and orderly construction. This chapter deals with those aspects of the facility, its design and construction which are integral parts to the overall performance of the site

  16. Divine development

    DEFF Research Database (Denmark)

    Agarwala, Rina

    2015-01-01

    position in the world system and support poverty alleviation efforts within a neoliberal development framework. Indian-American Muslims draw from their poor status in India to overturn economic inequities within India by shifting India's development rhetoric from identity to class. Collective religious......This article examines how Indian Americans’ religious organizations send not only financial remittances to India, but also social remittances that shape development ideologies. Comparing Indian-American Hindu and Muslim organizations, I find both groups draw from their socioeconomic experiences...... in India and use their position as elite immigrants in the United States to identify and empower their respective religious constituencies in India and overturn different social relations (not just religious practices). Hindu Americans draw from their majority status in India to overturn India's lower...

  17. Diagnostic development

    International Nuclear Information System (INIS)

    Barnett, C.F.; Brisson, D.A.; Greco, S.E.

    1978-01-01

    During the past year the far-infrared or submillimeter diagnostic research program resulted in three major developments: (1) an optically pumped 0.385-μm D 2 O-laser oscillator-amplifier system was operated at a power level of 1 MW with a line width of less than 50 MHz; (2) a conical Pyrex submillimeter laser beam dump with a retention efficiency greater than 10 4 was developed for the ion temperature Thompson scattering experiment; and (3) a new diagnostic technique was developed that makes use of the Faraday rotation of a modulated submillimeter laser beam to determine plasma current profile. Measurements of the asymmetric distortion of the H/sub α/ (6563 A) spectral line profile show that the effective toroidal drift velocity, dv/sub two vertical bars i/dT/sub i/, may be used as an indicator of plasma quality and as a complement to other ion temperature diagnostics

  18. Development economics

    International Nuclear Information System (INIS)

    Roebuck, F.

    1992-01-01

    This paper discusses term development economics which refers to the economic evaluation of investment opportunities that occur after the discovery well is drilled and completed. with specific regard to the techniques used and the economic yardsticks available for investment decisions. Three potential situations are considered in this paper: the incorporation of development wells into the outcomes of the original exploration project, mutually exclusive or alternative investment opportunities, and the installation of improved or enhanced recovery projects during or at the end of the primary producing life of a property

  19. Diverting Developments

    DEFF Research Database (Denmark)

    Taudal Poulsen, René

    2013-01-01

    developments in the two industries have diverted after 1970. All the large and medium-sized Danish shipyards have ceased, whereas several equipment suppliers have endured and some have built up strong positions within their respective fields. Focusing on corporate strategies in shipbuilding and marine...... equipment manufacturing, this article examines the diverting developments of the two industries and asks what has caused this divergence?......Over the last couple of decades, the shipbuilding and marine equipment industries in Denmark and elsewhere in Europe have been exposed to strong competition from new and rapidly expanding maritime nations in Asia. In the 1970s, Denmark had a stronghold in both industries, which have been closely...

  20. Development of a model using narrow slit beam profiles to account for the backscatter response of an amorphous silicon electronic portal imaging device

    International Nuclear Information System (INIS)

    Maria Das, K.J.; Ostapiak, Orest

    2008-01-01

    An electronic portal imaging device (EPID), currently used for determining proper patient placement during irradiation in a radiotherapy treatment, can also be used for the purpose of pre- treatment IMRT QA. However, the Varian aS500 portal imager exhibits dosimetric artifacts caused by non-uniform backscatter from mechanical support structures located behind the imager

  1. Interorganizational Development.

    Science.gov (United States)

    Schermerhorn, John R., Jr.

    1979-01-01

    Interorganizational development is the application of social science knowledge to the creation of planned, systematic and mutually beneficial cooperative relationships between otherwise autonomous organizations. This paper introduces the concept as a means of focusing attention on key action and research issues associated with interorganizational…

  2. Leadership Development

    OpenAIRE

    Oana Simona Hudea

    2014-01-01

    This paper aims at rendering the main characteristics distinguishing leaders from common individuals, as well as from managers, while identifying the progressive steps and the key elements needed for leader development. Learning how to lead oneself is a prerequisite for leading others, but without continuous training, coaching or mentoring, and above all, without effective experience, individuals will never get to become real leaders.

  3. New Developments

    Science.gov (United States)

    Lohmander, Maelis Karlson; Vandenbroeck, Michel; Pirard, Florence; Peeters, Jan; Alvestad, Marit

    2009-01-01

    New developments and challenges regarding early childhood education (ECE) policy and practice in Norway and in the Flemish and French communities in Belgium are presented in this issue. There are clear differences between the countries when comparing systems they have chosen for ECE. In Belgium, supervision and responsibilities for education,…

  4. Developing Globalization

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    2017-01-01

    This chapter is the first qualitative micro case study of one aspect of globalization: personal networks as a concrete outcome of development assistance spending. The empirical findings related in this paper present circumstantial evidence that Japanese foreign aid has contributed to globalization...

  5. Infrastructure Development

    DEFF Research Database (Denmark)

    Williams, Idongesit

    2012-01-01

    access and service of telecommunications/ICTs have been stalled. This paper throws light on a possible Public Private Partnership framework as a development path that will enable affordable network technologies to be deployed in rural areas at a cost that will translate to what the rural dweller...

  6. Process development

    International Nuclear Information System (INIS)

    Zapata G, G.

    1989-01-01

    Process development: The paper describes the organization and laboratory facilities of the group working on radioactive ore processing studies. Contains a review of the carried research and the plans for the next future. A list of the published reports is also presented

  7. Contraceptive Development.

    Science.gov (United States)

    Troen, Philip; And Others

    This report provides an overview of research activities and needs in the area of contraceptive development. In a review of the present state, discussions are offered on the effectiveness and drawbacks of oral contraceptives, intrauterine devices, barrier methods, natural family planning, and sterilization. Methods of contraception that are in the…

  8. Dairy development

    NARCIS (Netherlands)

    Leegwater, P.; Hoorweg, J.C.

    2000-01-01

    The growth of the dairy sector as it has occurred in Kilifi and Malindi Districts is one of the few examples of successful agricultural development in the coastal region in the past decades. Between 1985 and 1997 dairy cattle have more than doubled in number. Three livestock systems are described:

  9. Instrumentation development

    International Nuclear Information System (INIS)

    Ubbes, W.F.; Yow, J.L. Jr.

    1988-01-01

    Instrumentation is developed for the Civilian Radioactive Waste Management Program to meet several different (and sometimes conflicting) objectives. This paper addresses instrumentation development for data needs that are related either directly or indirectly to a repository site, but does not touch on instrumentation for work with waste forms or other materials. Consequently, this implies a relatively large scale for the measurements, and an in situ setting for instrument performance. In this context, instruments are needed for site characterization to define phenomena, develop models, and obtain parameter values, and for later design and performance confirmation testing in the constructed repository. The former set of applications is more immediate, and is driven by the needs of program design and performance assessment activities. A host of general technical and nontechnical issues have arisen to challenge instrumentation development. Instruments can be classed into geomechanical, geohydrologic, or other specialty categories, but these issues cut across artificial classifications. These issues are outlined. Despite this imposing list of issues, several case histories are cited to evaluate progress in the area

  10. Leadership Development

    Science.gov (United States)

    Mallon, Melissa

    2017-01-01

    This issue's column focuses on online tools and resources available for leadership development of academic, public services staff. The resources are not targeted solely to professional librarians, but rather to all levels of library staff engaged with the public. In addition to inspirational and coaching videos, reviewers recommend resource guides…

  11. Sustainable development

    International Nuclear Information System (INIS)

    Boiteux, M.

    2004-01-01

    Marcel Boiteux evokes the results of the work on the sustainable development by the Academie des Sciences Morales et Politiques. This is a vast political programme with the goal of allowing all humanity to live well in growing unity while protecting the environment and favouring economic growth. (author)

  12. Sustainable Development

    African Journals Online (AJOL)

    Tsegai Berhane Ghebretekle

    Ethiopia is selected as a case study in light of its pace in economic growth ... Interrogating the Economy-First Paradigm in 'Sustainable Development' … 65 .... agreement, since such effective global cooperation on climate change ultimately ..... and foster innovation; reduce inequality within and among countries; make cities.

  13. Engendering Development

    OpenAIRE

    Monsod, Solita C.

    1994-01-01

    This article discusses the productive and reproductive roles Filipino women perform and assesses their contributions to human development. It also examines the reality of their marginalization from the country’s social, economic and political life. It then suggests on measures by which women can be empowered to achieve the goals of gender equality and equity.

  14. Elaboração e implementação de um programa para verificação dos cálculos das unidades monitoras em radioterapia Development and implementation of a software for assessment of calculations in radiotherapy monitor units

    Directory of Open Access Journals (Sweden)

    Márcio Rogério Müller

    2005-12-01

    Full Text Available OBJETIVO: Desenvolvimento e implementação de um programa, fundamentado no algoritmo de cálculo manual, para verificação dos cálculos de unidades monitoras em radioterapia e estabelecimento de patamares de aceitação, como mecanismo de garantia da qualidade. MATERIAIS E MÉTODOS: Os dados apresentados foram obtidos a partir dos aceleradores lineares modelo Clinac 600C e 2100C, da Varian, e o sistema de planejamento de tratamento computadorizado utilizado foi o CadPlan™. RESULTADOS: Para os feixes de 6 MV os patamares de aceitação para desvios entre os cálculos de unidades monitoras, separados por região de tratamento, foram: mama (0,0% ± 1,7%, cabeça e pescoço (1,5% ± 0,5%, hipófise (-1,7% ± 0,5%, pelve (2,1% ± 2,1% e tórax (0,2% ± 1,3%. Para os feixes de 15 MV, o patamar sugerido para pelve em todas as técnicas de tratamento foi de (3,2% ± 1,3%. CONCLUSÃO: Os dados são suficientes para justificar seu uso na prática clínica como ferramenta no programa de garantia da qualidade.OBJECTIVE: To develop and implement a software based on the manual calculation algorithm for verification of the calculations in radiotherapy monitor units and to establish acceptance levels as a mechanism of quality assurance. MATERIALS AND METHODS: Data were obtained from Clinac 600C and 2100C Varian linear accelerators and the computerized treatment planning system used was CadPlan™. RESULTS: For the 6 MV beams the acceptance levels for deviations among the calculations of monitor units, divided by treatment area, were the following: breast (0.0% ± 1.7%, head and neck (1.5% ± 0.5%, hypophysis (-1.7% ± 0.5%, pelvis (2.1% ± 2.1% and thorax (0.2% ± 1.3%. For the 15 MV beams the suggested level for pelvis in all the treatment techniques was (3.2% ± 1.3%. CONCLUSION: The present data are sufficient to justify the use of the software in the clinical practice as a tool for the quality assurance program.

  15. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  16. EOS developments

    Science.gov (United States)

    Sindrilaru, Elvin A.; Peters, Andreas J.; Adde, Geoffray M.; Duellmann, Dirk

    2017-10-01

    CERN has been developing and operating EOS as a disk storage solution successfully for over 6 years. The CERN deployment provides 135 PB and stores 1.2 billion replicas distributed over two computer centres. Deployment includes four LHC instances, a shared instance for smaller experiments and since last year an instance for individual user data as well. The user instance represents the backbone of the CERNBOX service for file sharing. New use cases like synchronisation and sharing, the planned migration to reduce AFS usage at CERN and the continuous growth has brought EOS to new challenges. Recent developments include the integration and evaluation of various technologies to do the transition from a single active in-memory namespace to a scale-out implementation distributed over many meta-data servers. The new architecture aims to separate the data from the application logic and user interface code, thus providing flexibility and scalability to the namespace component. Another important goal is to provide EOS as a CERN-wide mounted filesystem with strong authentication making it a single storage repository accessible via various services and front- ends (/eos initiative). This required new developments in the security infrastructure of the EOS FUSE implementation. Furthermore, there were a series of improvements targeting the end-user experience like tighter consistency and latency optimisations. In collaboration with Seagate as Openlab partner, EOS has a complete integration of OpenKinetic object drive cluster as a high-throughput, high-availability, low-cost storage solution. This contribution will discuss these three main development projects and present new performance metrics.

  17. Bone development

    DEFF Research Database (Denmark)

    Tatara, M.R.; Tygesen, Malin Plumhoff; Sawa-Wojtanowicz, B.

    2007-01-01

    The objective of this study was to determine the long-term effect of alpha-ketoglutarate (AKG) administration during early neonatal life on skeletal development and function, with emphasis on bone exposed to regular stress and used to serve for systemic changes monitoring, the rib. Shropshire ram.......01). Furthermore, AKG administration induced significantly higher bone mineral density of the cortical bone by 7.1% (P

  18. Leadership Development

    Directory of Open Access Journals (Sweden)

    Oana Simona Hudea

    2014-12-01

    Full Text Available This paper aims at rendering the main characteristics distinguishing leaders from common individuals, as well as from managers, while identifying the progressive steps and the key elements needed for leader development. Learning how to lead oneself is a prerequisite for leading others, but without continuous training, coaching or mentoring, and above all, without effective experience, individuals will never get to become real leaders.

  19. SU-E-T-256: Development of a Monte Carlo-Based Dose-Calculation System in a Cloud Environment for IMRT and VMAT Dosimetric Verification

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Y [Tokai University School of Medicine, Isehara, Kanagawa (Japan)

    2015-06-15

    Purpose: Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are techniques that are widely used for treating cancer due to better target coverage and critical structure sparing. The increasing complexity of IMRT and VMAT plans leads to decreases in dose calculation accuracy. Monte Carlo simulations are the most accurate method for the determination of dose distributions in patients. However, the simulation settings for modeling an accurate treatment head are very complex and time consuming. The purpose of this work is to report our implementation of a simple Monte Carlo simulation system in a cloud-computing environment for dosimetric verification of IMRT and VMAT plans. Methods: Monte Carlo simulations of a Varian Clinac linear accelerator were performed using the BEAMnrc code, and dose distributions were calculated using the DOSXYZnrc code. Input files for the simulations were automatically generated from DICOM RT files by the developed web application. We therefore must only upload the DICOM RT files through the web interface, and the simulations are run in the cloud. The calculated dose distributions were exported to RT Dose files that can be downloaded through the web interface. The accuracy of the calculated dose distribution was verified by dose measurements. Results: IMRT and VMAT simulations were performed and good agreement results were observed for measured and MC dose comparison. Gamma analysis with a 3% dose and 3 mm DTA criteria shows a mean gamma index value of 95% for the studied cases. Conclusion: A Monte Carlo-based dose calculation system has been successfully implemented in a cloud environment. The developed system can be used for independent dose verification of IMRT and VMAT plans in routine clinical practice. The system will also be helpful for improving accuracy in beam modeling and dose calculation in treatment planning systems. This work was supported by JSPS KAKENHI Grant Number 25861057.

  20. SU-E-T-256: Development of a Monte Carlo-Based Dose-Calculation System in a Cloud Environment for IMRT and VMAT Dosimetric Verification

    International Nuclear Information System (INIS)

    Fujita, Y

    2015-01-01

    Purpose: Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are techniques that are widely used for treating cancer due to better target coverage and critical structure sparing. The increasing complexity of IMRT and VMAT plans leads to decreases in dose calculation accuracy. Monte Carlo simulations are the most accurate method for the determination of dose distributions in patients. However, the simulation settings for modeling an accurate treatment head are very complex and time consuming. The purpose of this work is to report our implementation of a simple Monte Carlo simulation system in a cloud-computing environment for dosimetric verification of IMRT and VMAT plans. Methods: Monte Carlo simulations of a Varian Clinac linear accelerator were performed using the BEAMnrc code, and dose distributions were calculated using the DOSXYZnrc code. Input files for the simulations were automatically generated from DICOM RT files by the developed web application. We therefore must only upload the DICOM RT files through the web interface, and the simulations are run in the cloud. The calculated dose distributions were exported to RT Dose files that can be downloaded through the web interface. The accuracy of the calculated dose distribution was verified by dose measurements. Results: IMRT and VMAT simulations were performed and good agreement results were observed for measured and MC dose comparison. Gamma analysis with a 3% dose and 3 mm DTA criteria shows a mean gamma index value of 95% for the studied cases. Conclusion: A Monte Carlo-based dose calculation system has been successfully implemented in a cloud environment. The developed system can be used for independent dose verification of IMRT and VMAT plans in routine clinical practice. The system will also be helpful for improving accuracy in beam modeling and dose calculation in treatment planning systems. This work was supported by JSPS KAKENHI Grant Number 25861057

  1. Annual report of Fusion Research and Development Directorate of JAEA for FY2008 and FY2009

    International Nuclear Information System (INIS)

    Isei, Nobuaki

    2011-03-01

    This annual report provides an overview of major results and progress on research and development (R and D) activities at Fusion Research and Development Directorate of Japan Atomic Energy Agency (JAEA) for FY2008 (from April 1, 2008 to March 31, 2009) and FY2009 (from April 1, 2009 to March 31, 2010), including those performed in collaboration with other research establishments of JAEA, research institutes, and universities. Concerning the ITER project, JAEA was nominated as the domestic agency by the Japanese government after the ITER Agreement took effect, and has fulfilled the obligations. In the development of superconducting conductors, JAEA constructed a technical platform for the fabrication of superconducting conductors for toroidal field (TF) coils ahead of other countries. JAEA immediately started and completed the construction of a plant to fabricate superconducting conductors, and started their fabrication ahead of other countries. In the development of gyrotron high-frequency heating equipment, since only the JAEA satisfies the ITER's procurement specifications among supplier countries, the ITER Organization requested JAEA to conduct confidence tests, and achieved results such as data acquisition that could contribute to the development of the ITER's operational scenario. For the development of neutral beam injectors, advantages of the multi-stage acceleration system developed by JAEA was recognized as a result of comparative experiments with single-stage acceleration systems developed in Europe for the particle acceleration system, and was adopted in the ITER's technical specifications. For the Broader Approach (BA) activities, JAEA was designated as the implementing agency by the Japanese government after the BA Agreement took effect, and has fulfilled the obligations and promoted three projects in the BA activities steadily through domestic cooperation and coordination with Europe. Concerning activities related to the International Fusion Energy

  2. Professional development

    Science.gov (United States)

    Yoon, Jin Hee; Hartline, Beverly Karplus; Milner-Bolotin, Marina

    2013-03-01

    The three sessions of the professional development workshop series were each designed for a different audience. The purpose of the first session was to help mid-career physicists aspire for and achieve leadership roles. The second session brought together students, postdoctoral fellows, and early-career physicists to help them plan their career goals and navigate the steps important to launching a successful career. The final session sought to increase awareness of the results of physics education research, and how to use them to help students-especially women-learn physics better. The presentations and discussions were valuable for both female and male physicists.

  3. 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

  4. Energy development

    Science.gov (United States)

    Lovich, Jeffrey E.; Jones, L.L.C.; Lovich, R. L.; Halama, K.J.

    2016-01-01

    Large areas of the desert southwest are currently developed or being evaluated for construction of utility-scale renewable energy projects. These projects include numerous solar and wind energy facilities some of which will be massive. Unfortunately, peer-reviewed scientific publications are not yet available to evaluate the potential effects of solar-based utility-scale renewable energy development (USRED) on any species of wildlife, including amphibians and reptiles (herpetofauna). Scientific publications on the effects of wind-based USRED and operation (USREDO) are focused almost exclusively on flying wildlife including birds and bats. To the best of our knowledge the only publications on the effects of wind-based USREDO on herpetofauna are three publications on desert tortoise ecology at a wind energy facility near Palm Springs, California. Those studies suggested that not all effects of USREDO were detrimental in the short-term. However, additional research is required to determine if wind energy operation is compatible with conservation of this long-lived species over longer periods of time.

  5. Accelerator development

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Because the use of accelerated heavy ions would provide many opportunities for new and important studies in nuclear physics and nuclear chemistry, as well as other disciplines, both the Chemistry and Physics Divisions are supporting the development of a heavy-ion accelerator. The design of greatest current interest includes a tandem accelerator with a terminal voltage of approximately 25 MV injecting into a linear accelerator with rf superconducting resonators. This combined accelerator facility would be capable of accelerating ions of masses ranging over the entire periodic table to an energy corresponding to approximately 10 MeV/nucleon. This approach, as compared to other concepts, has the advantages of lower construction costs, lower operating power, 100 percent duty factor, and high beam quality (good energy resolution, good timing resolution, small beam size, and small beam divergence). The included sections describe the concept of the proposed heavy-ion accelerator, and the development program aiming at: (1) investigation of the individual questions concerning the superconducting accelerating resonators; (2) construction and testing of prototype accelerator systems; and (3) search for economical solutions to engineering problems. (U.S.)

  6. Injection control development of the JT-60U electron cyclotron heating system

    Energy Technology Data Exchange (ETDEWEB)

    Hiranai, Shinichi; Shinozaki, Shin-ichi; Yokokura, Kenji; Moriyama, Shinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sato, Fumiaki [Nippon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan); Suzuki, Yasuo [Atomic Energy General Service Co., Ltd., Tokai, Ibaraki (Japan); Ikeda, Yoshitaka [Japan Atomic Energy Research Inst., Kashiwa, Chiba (Japan)

    2003-03-01

    The JT-60U electron cyclotron heating (ECH) System injects a millimeteric wave at 110 GHz into the JT-60 Plasma, and heats the plasma or drives a current locally to enhance the confinement performance of the JT-60 plasma. The system consists of four sets of high power gyrotrons, high voltage power supplies and transmission lines, and two antennas that launch electron cyclotron (EC) beams toward the plasma. The key features of the injection control system are streering of the direction of the EC beam by driving the movable mirror in the antenna, and capability to set any combination of polarization angle and ellipticity by rotating the two grooved mirrors in the polarizers. This report represents the design, fabrication and improvements of the injection control system. (author)

  7. Development of chromatographic methods for the determination of genotoxic impurities in cloperastine fendizoate.

    Science.gov (United States)

    García, Antonia; Rupérez, Francisco J; Ceppa, Florencia; Pellati, Federica; Barbas, Coral

    2012-03-05

    The classification of an impurity of a drug substance as genotoxic means that the "threshold of toxicological concern" (TTC) value of 1.5 μg/day intake, considered to be associated with an acceptable risk, should be the admissible limit in the raw material and that leads to new analytical challenges. In this study, reliable chromatographic methods were developed and applied as limit tests for the control of three genotoxic impurities (GTIs) in cloperastine fendizoate, drug widely used as an antitussive active pharmaceutical ingredient (API). In particular, GC-MS was applied to the determination of one alkyl halide (2-chloroethanol, 2-CE), while HPLC-DAD was selected for the analysis of two sulfonate esters (methyl p-toluenesulfonate, MPTS, and 2-chloroethyl p-toluenesulfonate, CEPTS). Regarding GC-MS, strong anion-exchange (SAX)-SPE was applied to remove fendizoate from the sample solutions, due its low volatility and its high amount in the raw material. The GC-MS analysis was performed on a Factor Four VF-23 ms capillary column (30 m × 0.25 mm I.D., film thickness 0.25 μm, Varian). Single ion-monitoring (SIM) detection mode was set at m/z 80. In the case of HPLC-DAD, a suitable optimization of the chromatographic conditions was carried out in order to obtain a good separation of the impurity peaks from the drug substance peaks. The optimized method utilizes a SymmetryShield RP(8) column (250 mm × 4.6 mm, 5 μm, Waters) kept at 50°C, with phosphate buffer (pH 3.0; 10 mM)-methanol (containing 10% ACN) (45:55, v/v) as the mobile phase, at the flow-rate of 1.7 mL/min and UV detection at 227 nm. The required sensitivity level was achieved by injecting 80 μL of sample solution, purified from fendizoate by SAX-SPE, followed by a 1:1 (v/v) dilution of the SPE eluate with water. For both GC-MS and HPLC-DAD, the method validation was performed in relation to specificity and limit of detection (LOD), as required by ICH guidelines in relation to limit assays. The

  8. Heating filament system of a Mig-type electron gun for a 35 GHz, 100 k W gyrotron

    International Nuclear Information System (INIS)

    Patire Junior, H.; Barroso, J.J.; Spassovsky, I.P.; Rossi, J.O.

    1993-01-01

    Cathode temperature tests of a Mig-type electron gun have been performed to determine the temperature of the electron emitting surface as a function of heater voltage and current. The test have been conducted partway through the construction phase of the gun as a means to minimize both the necessary heater input power and to reduce radiating of gun components. (author)

  9. Thermal and mechanical study of a MIG-type electron gun for a 31 GHz, 100 k W gyrotron

    International Nuclear Information System (INIS)

    Patire Junior, H.; Barroso, J.J.

    1994-01-01

    A thermal and mechanical study of a MIG-type electron gun has been made to determine the temperature distribution in all the gun elements as a function of the input heater power. Appropriate materials were selected to minimize both the conduction and radiation thermal losses. The electron emitting surface operates at an average temperature of 1000 0 C with 374 W input power in the heating filament system. The purpose of the present study is to reduce the input heater power while keeping the required operating cathode temperature and to improve the gun design from a constructional point of view aiming at extending the capabilities of the electron gun. A thermal software has been used by considering the operation conditions taking into account external convection by forced air and thermal radiation transfer between the electrodes of the gun. (author). 5 refs, 4 figs, 1 tab

  10. Biofilm Development

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2015-01-01

    During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction or terminat......During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction...... or termination of biofilm matrix production via the second messenger molecule c-di-GMP. In between initiation and termination of biofilm formation we have defined specific biofilm stages, but the currently available evidence suggests that these transitions are mainly governed by adaptive responses......, and not by specific genetic programs. It appears that biofilm formation can occur through multiple pathways and that the spatial structure of the biofilms is species dependent as well as dependent on environmental conditions. Bacterial subpopulations, e.g., motile and nonmotile subpopulations, can develop...

  11. SU-F-J-28: Development of a New Imaging Filter to Remove the Shadows From the Carbon Fiber Grid Table Top

    Energy Technology Data Exchange (ETDEWEB)

    Maehana, W [Kanagawa Cancer Center, Yokohama, Kanagawa (Japan); Yokohama National University, Yokohama, kanagawa (Japan); Nagao, T [Yokohama National University, Yokohama, kanagawa (Japan)

    2016-06-15

    Purpose: For the image guided radiation therapy (IGRT), the shadows caused by the construction of the treatment couch top adversely affect the visual evaluation. Therefore, we developed the new imaging filter in order to remove the shadows. The performance of the new filter was evaluated using the clinical images. Methods: The new filter was composed of the band-pass filter (BPF) weighted by the k factor and the low-pass filter (LPF). In the frequency region, the stop bandwidth were 8.3×10{sup 3} mm{sup −1} on u direction and 11.1×10{sup 3} mm{sup −1} on v direction for the BPF, and the pass bandwidth were 8.3×10{sup 3} mm{sup −1} on u direction and 11.1×10{sup 3} mm{sup −1} on v direction for the LPF. After adding the filter, the shadows from the carbon fiber grid table top (CFGTT, Varian) on the kV-image was removed. To check the filter effect, we compared the clinical images, which are thorax and thoracoabdominal region, with to without the filter. The subjective evaluation tests was performed by adapting a three-point scale (agree, neither agree nor disagree, disagree) about the 15 persons in the department of radiation oncology. Results: We succeeded in removing all shadows of CFGTT using the new filter. This filter is very useful shown by the results of the subjective evaluation having the 23/30 persons agreed to the filtered clinical images. Conclusion: We concluded that the proposed method was useful tool for the IGRT and the new filter leads to improvement of the accuracy of radiation therapy.

  12. Development of a head phantom to be used for quality control in stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Barbosa, Nilseia Aparecida

    2010-05-01

    It was designed and developed a geometric acrylic head phantom (GHP) for Quality Assurance (QA) in Stereotactic Radiosurgery (SRS). Inside the phantom there are inserts that are able to accommodate acrylic targets representing the tumor tissue and organ at risk in the region cranial brain, the brain stem. The tumor tissue is represented by two semi-spheres of acrylic with a diameter of 13.0 mm and cavities in the central region for accommodation of a TLD-100 detector and a small radiochromic EBT Gafchromic filmstrip. The brain stem is represented by the two parts of acrylic cylinder with a diameter 18.0 mm, 38.0 mm length and cavities along the central region to accommodate the 5 detectors TLD-100 and yet another of EBT film. The distance tumor - brain stem is 2.0 mm. The experimental setup was filled with water, attached to the stereotactic frame to determine the coordinates of the target and underwent computed tomography (CT). Cf images were transferred to the SRS planning system BrainLab (BrainScan). The contours of the lesion and organ at risk were delineated and, through the technique of multiple circular arcs, the planning was conduced with five arches, one isocenter and a collimator of 17.5 mm from the combination between the table and gantry . The dose delivered to the isocenter of the lesion was 3.0 Gy and the total coverage of tumor volume corresponds to the 75% isodose. This experimental arrangement is subjected to radiosurgery treatment, after which the dosimeters are evaluated and their responses compared with the values of planned doses. The linear accelerator used was a Varian CLlNAC 2300 CID, photon beam of 6 MV, installed at the National Cancer Institute (INCA). For verification of dose distributions in 3D, the films were irradiated in three planes: sagittal, caronal and axial. The .films were scanned and digitized on a scanner Microtek ScanMaker 9800XL model. The dose distributions in irradiated films were compared with the distributions of doses

  13. MO-FG-202-03: Efficient Data Collection of Continuous 2D and Discrete Relative Dosimetric Data for Annual LINAC QA Using TrueBeam Developer Mode and a 1D Scanning Tank

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, N; Schmidt, M [Rhode Island Hospital, Providence, RI (United States); University of Rhode Island, Kingston, RI (United States); University of Massachusetts Lowell, Lowell, MA (United States); Nguyen, N [Rhode Island Hospital, Providence, RI (United States); University of Massachusetts Lowell, Lowell, MA (United States); Belley, M [Rhode Island Hospital, Providence, RI (United States); University of Rhode Island, Kingston, RI (United States); Price, M [Rhode Island Hospital, Providence, RI (United States); University of Rhode Island, Kingston, RI (United States); Alpert Medical School of Brown University, Providence, RI (United States)

    2016-06-15

    Purpose: To develop a method to exploit real-time dynamic machine and couch parameter control during linear accelerator (LINAC) beam delivery to facilitate efficient performance of TG-142 suggested, Annual LINAC QA tests. Methods: Varian’s TrueBeam Developer Mode (Varian Medical Systems, Palo Alto, CA) facilitates control of Varian’s TrueBeam LINAC via instructions provided in Extensible Markup Language (XML) files. This allows machine and couch parameters to be varied dynamically, in real-time, during beam delivery. Custom XML files were created to allow for the collection of (1) continuous Tissue Maximum Ratios (TMRs), (2) beam profiles, and (3) continuous output factors using a 1D-scanning tank. TMRs were acquired by orienting an ionization chamber (IC) at isocenter (depth=25cm) and synchronizing a depth scan towards the water surface while lowering the couch at 1mm/s. For beam profiles, the couch was driven laterally and longitudinally while logging IC electrometer readings. Output factors (OFs) where collected by continually varying field sizes (4×4 to 30×30-cm{sup 2}) at a constant speed of 6.66 mm/s. To validate measurements, comparisons were made to data collected using traditional methods (e.g. 1D or 3D tank). Results: All data collecting using the proposed methods agreed with traditionally collected data (TMRs within 1%, OFs within 0.5% and beam profile agreement within 1% / 1mm) while taking less time to collect (factor of approximately 1/10) and with a finer sample resolution. Conclusion: TrueBeam developer mode facilitates collection of continuous data with the same accuracy as traditionally collected data with a finer resolution in less time. Results demonstrate an order of magnitude increase in sampled resolution and an order of magnitude reduction in collection time compared to traditional acquisition methods (e.g. 3D scanning tank). We are currently extending this approach to perform other TG-142 tasks.

  14. Introduction: translocal development, development corridors and development chains.

    NARCIS (Netherlands)

    Zoomers, E.B.; Westen, A.C.M. van

    2011-01-01

    This paper offers an introduction to this Special Issue of International Development Planning Review. It uses the concepts of translocal development, development corridors and development chains to secure a better grasp of what development means in the context of globalisation and how ‘local

  15. SU-E-T-641: Development and Verification of Automatic Reading Dose of Interest From Eclipse's DVH

    International Nuclear Information System (INIS)

    Wu, Q

    2014-01-01

    Purpose: According to clinical and research requirement, we develop a function of automatic reading dose of interest from dose volume histogram(DVH), to replace the traditional method with a mouse one by one point, and it's also verified. Methods: The DVH automatic reading function will be developed in an in-house developed radiotherapy information management system(RTIMS), which is based on Apache+PHP+MySQL. A DVH ASCII file is exported from Varian Eclipse V8.6, which includes the following contents: 1. basic information of patient; 2. dose information of plan; 3. dose information of structures, including basic information and dose volume data of target volume and organ at risk. And the default exported dose volume data also includes relative doses by 1% step and corresponding absolute doses and cumulative relative volumes, and the volumes are 4 decimal fraction. Clinically, we often need read the doses of some integer percent volumes, such as D50 and D30. So it couldn't be directly obtained from the above data, but we can use linear interpolation bye the near volumes and doses: Dx=D2−(V2−Vx)*(D2−D1)/(V2−V1), and program a function to search, read and calculate the corresponding data. And the doses of all preseted volume of interest of all structures can be automatically read one by one patient, and saved as a CSV file. To verify it, we select 24 IMRT plans for prostate cancer, and doses of interest are PTV D98/D95/D5/D2, bladder D30/D50, and rectum D25/D50. Two groups of data, using the automatic reading method(ARM) and pointed dose method(PDM), are analyzed with SPSS 16. The absolute difference=D-ARM-D-PDM, relative difference=absolute difference*100%/prescription dose(7600cGy). Results: The differences are as following: PTV D98/D95/D5/D2: −0.04%/− 0.04%/0.13%/0.19%, bladder D30/D50: −0.02%/0.01%, and rectum D25/D50: 0.03%/0.01%. Conclusion: Using this function, the error is very small, and can be neglected. It could greatly improve the

  16. SU-E-T-641: Development and Verification of Automatic Reading Dose of Interest From Eclipse's DVH

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q [Department of Radiation Oncology, Beijing Hospital, Ministry of Health, Beijing (China)

    2014-06-15

    Purpose: According to clinical and research requirement, we develop a function of automatic reading dose of interest from dose volume histogram(DVH), to replace the traditional method with a mouse one by one point, and it's also verified. Methods: The DVH automatic reading function will be developed in an in-house developed radiotherapy information management system(RTIMS), which is based on Apache+PHP+MySQL. A DVH ASCII file is exported from Varian Eclipse V8.6, which includes the following contents: 1. basic information of patient; 2. dose information of plan; 3. dose information of structures, including basic information and dose volume data of target volume and organ at risk. And the default exported dose volume data also includes relative doses by 1% step and corresponding absolute doses and cumulative relative volumes, and the volumes are 4 decimal fraction. Clinically, we often need read the doses of some integer percent volumes, such as D50 and D30. So it couldn't be directly obtained from the above data, but we can use linear interpolation bye the near volumes and doses: Dx=D2−(V2−Vx)*(D2−D1)/(V2−V1), and program a function to search, read and calculate the corresponding data. And the doses of all preseted volume of interest of all structures can be automatically read one by one patient, and saved as a CSV file. To verify it, we select 24 IMRT plans for prostate cancer, and doses of interest are PTV D98/D95/D5/D2, bladder D30/D50, and rectum D25/D50. Two groups of data, using the automatic reading method(ARM) and pointed dose method(PDM), are analyzed with SPSS 16. The absolute difference=D-ARM-D-PDM, relative difference=absolute difference*100%/prescription dose(7600cGy). Results: The differences are as following: PTV D98/D95/D5/D2: −0.04%/− 0.04%/0.13%/0.19%, bladder D30/D50: −0.02%/0.01%, and rectum D25/D50: 0.03%/0.01%. Conclusion: Using this function, the error is very small, and can be neglected. It could greatly improve the

  17. SU-E-T-110: Development of An Independent, Monte Carlo, Dose Calculation, Quality Assurance Tool for Clinical Trials

    Energy Technology Data Exchange (ETDEWEB)

    Faught, A [UT MD Anderson Cancer Center, Houston, TX (United States); University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, TX (United States); Davidson, S [University of Texas Medical Branch of Galveston, Galveston, TX (United States); Kry, S; Ibbott, G; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States); Fontenot, J [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Etzel, C [Consortium of Rheumatology Researchers of North America (CORRONA), Inc., Southborough, MA (United States)

    2014-06-01

    Purpose: To develop a comprehensive end-to-end test for Varian's TrueBeam linear accelerator for head and neck IMRT using a custom phantom designed to utilize multiple dosimetry devices. Purpose: To commission a multiple-source Monte Carlo model of Elekta linear accelerator beams of nominal energies 6MV and 10MV. Methods: A three source, Monte Carlo model of Elekta 6 and 10MV therapeutic x-ray beams was developed. Energy spectra of two photon sources corresponding to primary photons created in the target and scattered photons originating in the linear accelerator head were determined by an optimization process that fit the relative fluence of 0.25 MeV energy bins to the product of Fatigue-Life and Fermi functions to match calculated percent depth dose (PDD) data with that measured in a water tank for a 10x10cm2 field. Off-axis effects were modeled by a 3rd degree polynomial used to describe the off-axis half-value layer as a function of off-axis angle and fitting the off-axis fluence to a piecewise linear function to match calculated dose profiles with measured dose profiles for a 40×40cm2 field. The model was validated by comparing calculated PDDs and dose profiles for field sizes ranging from 3×3cm2 to 30×30cm2 to those obtained from measurements. A benchmarking study compared calculated data to measurements for IMRT plans delivered to anthropomorphic phantoms. Results: Along the central axis of the beam 99.6% and 99.7% of all data passed the 2%/2mm gamma criterion for 6 and 10MV models, respectively. Dose profiles at depths of dmax, through 25cm agreed with measured data for 99.4% and 99.6% of data tested for 6 and 10MV models, respectively. A comparison of calculated dose to film measurement in a head and neck phantom showed an average of 85.3% and 90.5% of pixels passing a 3%/2mm gamma criterion for 6 and 10MV models respectively. Conclusion: A Monte Carlo multiple-source model for Elekta 6 and 10MV therapeutic x-ray beams has been developed as a

  18. Wills Plasma Physics Department annual progress report 1984

    International Nuclear Information System (INIS)

    1984-01-01

    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

  19. Leading and Managing Continuing Professional Development: Developing People, Developing Schools

    Science.gov (United States)

    Earley, Peter; Bubb, Sara

    2004-01-01

    This book has been written for those who lead and manage continuing professional development (CPD). Continuing professional development co-coordinators hold a key role and one that needs to be developed further in many schools. This book is intended to help people think more deeply about the professional development and training of staff--all…

  20. TH-C-12A-12: Veritas: An Open Source Tool to Facilitate User Interaction with TrueBeam Developer Mode

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, P [Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Varian Medical Systems, Palo Alto, CA (United States); Lewis, J [Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Etmektzoglou, T; Svatos, M [Varian Medical Systems, Palo Alto, CA (United States)

    2014-06-15

    developments and collaboration with other researchers. I am an employee of Varian Medical Systems.