RF power structures and systems
Paper Title Page
THCCH01
 Pulse Power System for New Industrial Accelerator ILU-14  
 
  • V.V. Bezuglov, A.A. Bryazgin, B.L. Faktorovich, E.N. Kokin, V.M. Radchenko, E.A. Shtarklev, A. YU. Vlasov
    BINP SB RAS, Novosibirsk, Russia
  
  Accelerator ILU-14 consist of multi resonator accelerating structure and two cascade HF generator. Two cascade HF generator consists of primary generator and four terminal generators. It has demanded development of a pulse power source capable to provide 16 MW pulse power. Choice of creation of the modulator reaching such parameters or using of several standard modulators supplying accelerators of ILU type (up to 30 KV, 250 A, 500 mks, 50 Hz), has been made in favour of the joint work of three modulators powering HF generator. This report consist of the way of an unitization of three modulators for a power supply of the two cascade HF generator, It's describe a problem of this power supply configuration and the way of their solution. Also the control system of three modulator pulse power structure and results of the work are presented.  
slides icon Slides THCCH01 [1.004 MB]  
 
THCCH02 Characteristics of the Model of Linear Accelerator Based on Parallel Coupled Accelerating Structure with Beam Loading 164
 
  • Y.D. Chernousov
    ICKC, Novosibirsk, Russia
  • A.M. Barnyakov, A.E. Levichev, V.M. Pavlov
    BINP SB RAS, Novosibirsk, Russia
  • V. Ivannikov, I.V. Shebolaev
    ICKC SB RAS, Novosibirsk, Russia
  
  The 5-cavity model of linear accelerator based on the parallel coupled accelerating structure (LAPCAS) is under study. Linear accelerator is equipped with focusing system based on permanent magnet and three-electrode gun with RF control. The work of accelerator with electron beam is demonstrated. The parameters of short pulses mode are following: electron energy - 4 MeV, pulse current - 0.3 A, pulse duration - 2.5 ns; the parameters of long pulses mode are following: energy - 2.5 MeV, pulse current - 0. 1A, pulse duration - 0.1 - 4 us. Working frequency of the accelerator is 2.45 GHz. In RF-controlled mode the capture of about 100% is demonstrated. The beam loading effect is observed. The compensation of energy spread of accelerated electrons by delaying the moment of injection in the LAPCAS is demonstrated. The equations of transient process in the accelerating cavity which is powered by an external RF generator and excited by electron bunches in a simple form are presented.  
slides icon Slides THCCH02 [1.154 MB]  
 
MOPPA018 Localization of the RF Breakdown in the Parallel Coupled Accelerating Structure 281
 
  • Y.D. Chernousov, A.M. Barnyakov, A.E. Levichev, V.M. Pavlov
    BINP SB RAS, Novosibirsk, Russia
  • V. Ivannikov, I.V. Shebolaev
    ICKC SB RAS, Novosibirsk, Russia
  
  Parallel coupled accelerating structures (PCAS) with parallel RF power feeding of accelerating cavities has some features and advantages in compare with conventional traveling wave and standing wave structures with sequential RF power feeding. Parallel feeding of accelerating cavities minimizes the RF power flow via coupling slot and determines individual behavior of each cell in the regime of RF breakdown. These features can be used for developing of high gradient accelerating structures. The experimental data of the breakdown modes in the PCAS are presented.  
 
MOPPA019 RF Antenna Lead 284
 
  • A.M. Barnyakov, A.E. Levichev
    BINP SB RAS, Novosibirsk, Russia
  • Y.D. Chernousov
    ICKC, Novosibirsk, Russia
  • V. Ivannikov, I.V. Shebolaev
    ICKC SB RAS, Novosibirsk, Russia
  
  RF antenna lead is described. This lead is used for RF power input to high voltage electrodes. The device consists of receiving and transmitting antennas realized as symmetrical parts of coaxial cavity with dielectric disk between the parts. Main operating characteristics are the following: high voltage is over 60 kV, coefficient of transmission at the operating frequency is over 0.97, bandpass is over 70% (at the level of -3dB). The scheme of the device, principle of work and measured results are presented.  
 
MOPPA020 Multipactor Discharge in eLINAC Accelerator 287
 
  • M. Gusarova, I.I. Petrushina
    MEPhI, Moscow, Russia
  • V. Zvyagintsev
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  
  This paper concerns numerical simulations and experimental investigation of multipacting discharge in accelerating cavities and feeding waveguide section of eLINAC accelerator. The threshold values of accelerating gradient and input power for discharge may occur in these structures have been obtained experimentally and compared to numerical predictions. Secondary emission influence on discharge behavior were also considered.  
 
MOPPA021 176 MHz Solid State Microwave Generator Design 290
 
  • A.Yu. Smirnov, E.V. Ivanov, K.I. Nikolskiy, S.A. Polikhov, N.V. Tikhomirova
    Siemens Research Center, Moscow,, Russia
  • O. Heid, T.J.S. Hughes
    Siemens AG, Erlangen, Germany
  
  This paper concerns the R&D work upon design of a compact RF amplifier to be used for linear accelerators. The machine under development will operate at 176 MHz with output power of 25 kW in continuous wave regime. It consists of 48 push-pull PCB modules (approx. 500W output power each), connected in parallel to several radial filter rings, which both allow class-F operation and combine the power from the modules, delivering it to a single 50 Ω coax cable. The CST simulations and the results of 324 MHz test prototype measurements are presented.  
 
MOPPA022 Status of INR DTL RF System 293
 
  • A.I. Kvasha, A. Feschenko, V.L. Serov
    RAS/INR, Moscow, Russia
  
  INR Linac is in regular operation since 1993. The accelerator incorporates DTL and DAW structures operating at 198.2 MHz and 991 MHz correspondingly. Initially two types of high power vacuum tubes specially designed for INR linac (GI-54A for final amplifier and GI-51A for intermediate amplifier) were used in DTL RF power system. However production of these tubes has been terminated resulting in a need of DTL RF system upgrade. The main goal of the recent upgrade is replacement of the old tubes by modern ones. The difficulty of replacement arises due to a need to minimize mechanical changes of the existing equipment. Another goal is improving of operational reliability. The reliability depends on vacuum tube reliability and to a large extent - on crowbar operation. The results and the experience of INR DTL RF system upgrade are presented  
 
MOPPA023 Investigation of INR DTL RF System Operation at 100 Hz Repetition Rate 296
 
  • V.L. Serov, A.N. Drugakov, A. Feschenko, A.I. Kvasha, A.N. Naboka
    RAS/INR, Moscow, Russia
  
  INR Linac has been operating with 50 Hz beam repetition rate so far. Increasing the repetition rate up to 100 Hz is of importance as it results in doubling of the beam intensity. To solve the task several accelerator systems must be modernized but the most critical one is the DTL rf system (up to 100 MeV). The problems related to the DTL rf system repetition rate increasing are described. One of them is a 50 Hz modulation of a 100 Hz rf pulse sequence. Though the instabilities of accelerating field due to the modulation are reduced by the feedback systems, nevertheless exploration of the effect and its minimizing is of importance. The analysis of the effect is given and the results of experimental studies are presented.  
 
MOPPA024
 Proposal of New Version of Modulator for LUE-200 LINAC  
 
  • A.P. Sumbaev, V. Kobets, V.N. Shvetsov
    JINR, Dubna, Moscow Region, Russia
  
  The new version of the modulator for powerful (50 - 80 MW) S-band klystron as a source of RF power for accelerating system of linac LUE-200 of IREN installation, based on modern element base is presented. By results of the analysis of design parametres and the requirements shown to the modulator, technical offers on the device, a forming line and switchboards are formulated. Settlement schemes and cost estimations of the offered technical decisions are resulted.  
 
MOPPA025
 Characteristics Research and Improvement of the High Power S-Band Klystron RF Sources on Linacs  
 
  • Y.D. Tur
    NSC/KIPT, Kharkov, Ukraine
  
  Results on characteristics research, parameters improvement and upgrading of high power S-band klystrons KIU-12 "AURORA" and KIU-53 "ARKHAR", executed in the process of development, implementation, industrial production and exploitation on the linear electron accelerators are presented. Data on design and research of parameters of sample quantity of high-efficiency 40 MW klystrons "ARSENAL" are also submitted.  
 
MOPPA026
 The Deflecting Cavities (Wobbler) Assembling for High-Energy Heavy Ion Hollow Beam Formation  
 
  • A. Sitnikov, A. Golubev, V.A. Koshelev, T. Kulevoy, S. Minaev
    ITEP, Moscow, Russia
  • E. Suleymenov
    MEPhI, Moscow, Russia
  
  Funding: "Rosatom", contract #N.4e.45.90.1065
The study of high-energy-density in matter (HEDM) is one of the most challenging and interesting topics in modern physics. An intense ion beam can be used to achieve low-entropy compression of a sample material like hydrogen or ice that is enclosed in a heavy cylindrical tamper shell. Such a target will be driven by a hollow beam with an annular focal spot. This experiment was called LAPLAS (Laboratory Planetary Sciences) at the FAIR project*. In the experiment, it will be possible to achieve physical conditions that exist in the interior of giant planets, Jupiter and Saturn. Another goal of the LAPLAS experiment will be to study the problem of hydrogen metallization. In order to make a hollow beam with an annular focal spot it has been proposed to rotate the ion beam around the longitudinal axis with a high frequency using a radio frequency deflecting system (Wobbler). The Wobbler consisted of two four-cell H-mode deflecting cavities with a resonant frequency of 297 MHz is under development. The deflecting cavities of the Wobbler system were manufactured and assembled. The measured electro-dynamics characteristics of the cavities as well as methods used for the cavities frequency tuning are presented.
* High Energy Density Matter Research Using Intense Heavy Ion Beams at the Future FAIR Facility at Darmstadt, N A Tahir et. al., IFSA2007 		 
 
MOPPA028
 Design and Simulation of 505.8 MHz Strip Line Ferrite Circulator for Indus 2  
 
  • M. Ahlawat, R.S. Shinde
    RRCAT, Indore (M.P.), India
  
  Circulator is an amazing device which can couple the power entering in anyone of its ports to the next port in one rotation only, and offers high isolation in reverse direction. Circulators find most wide applications in RF systems as a duplexer, and as an isolator with third port terminated with matched load. In particle accelerators ferrite circulators are used for the attenuation of reflected back power from a mismatched load or cavity to RF source to avoid the damage of RF source. To meet this requirement a strip line ferrite circulator has been designed and simulated using CST MICROWAVE STUDIO at 505.8 MHz for Indus 2 applications. Circulator geometries and biasing DC fields have been optimized (above resonance), and good results are observed with high reflection of 27 dB, with 30 dB isolation and 0.4 dB insertion loss. A MATLAB program has been developed for automatic calculations of circulator geometries, for given frequency and design parameters. Also thermal analysis has been done by observing the temperature rise with input power using thermally coupled simulation in CST Microwave studio. For 1000 watt input power maximum temperature in the circulator is 79 C without any forced cooling. This paper presents the design aspects, calculations and electromagnetic and thermal simulation of ferrite circulator.