03 Technology
3C RF Power Sources and Power Couplers
Paper Title Page
SUPB024 Development of Permanent Magnet Focusing System for Klystrons 62
 
  • Y. Fuwa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • S. Fukuda, S. Michizono
    KEK, Ibaraki, Japan
 
  The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.  
 
SUPB032 The C-band RF Pulse Compression for Soft XFEL at SINAP 83
 
  • C.P. Wang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
 
  A compact soft X-ray free electron laser facility is presently being constructed at shanghai institute of applied physics (SINAP), Chinese academy of science in 2012 and will be accomplished in 2014. This facility requires a compact linac with a high-gradient accelerating structure for a limited overall length less than 230 m. The c-band technology which is already used in KEK/Spring-8 linear accelerator is a good compromise for this compact facility and a c-and traveling-wave accelerating structure was already fabricated and tested at SINAP, so a c-band pulse compression will be required. AND a SLED type RF compression scheme is proposed for the C-band RF system of the soft XFEL and this scheme uses TE0.1.15 mode energy storage cavity for high Q-energy storage. The C-band pulse compression under development at SINAP has a high power gain about 3.1 and it is designed to compress the pulse width from 2.5 μs to 0.5 μs and multiply the input RF power of 50 MW to generate 160 MW peak RF power, and the coupling coefficient will be 8.5. It has three components: 3 dB coupler, mode convertors and the resonant cavities.  
 
TUPLB12 Development of Permanent Magnet Focusing System for Klystrons 470
 
  • Y. Fuwa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • S. Fukuda, S. Michizono
    KEK, Ibaraki, Japan
 
  The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.  
slides icon Slides TUPLB12 [1.357 MB]  
 
TUPB090 Development of Permanent Magnet Focusing System for Klystrons 669
 
  • Y. Fuwa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • S. Fukuda, S. Michizono
    KEK, Ibaraki, Japan
 
  A permanent magnet focusing system for klystrons is under development to improve reliability of RF supply system and reduce power consumption. To save production cost, anisotropic ferrite magnets are used in this system. A test model has been fabricated and the power test of a 750 kW klystron with this focusing magnet is carried out. 60 % of the nominal output power has been achieved at a preliminary power test so far  
 
TUPB091 176 MHz Solid State Microwave Generator Design 672
 
  • A.Yu. Smirnov, E.V. Ivanov, A.A. Krasnov, K.I. Nikolskiy, 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 superconducting CW cavities. The machine under development will operate at 176 MHz with output power of 25 kW in continuous wave regime. It consists of 50 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 ad the design of 324 MHz test prototype are presented.  
 
TUPB092 High Power Amplifier Systems for SARAF Phase II 675
 
  • B. Kaizer, I. Fishman, I.G. Gertz
    Soreq NRC, Yavne, Israel
 
  Soreq NRC initiated the establishment of SARAF - Soreq Applied Research Accelerator Facility. SARAF is based on a continuous wave (CW), proton/deuteron RF superconducting linear accelerator with variable energy (5–40 MeV) and current (0.04-5 mA). RF power to each cavity is driven by a High Power Solid State Amplifiers. The paper outlines the design concept of the 10 and 15 kW at 176 MHz power amplifiers that were designed, built, and 10 kW successfully tested. 15 kW is now under construction. The amplifiers are combined from basic 5.5 kW compact 19" 7U water cooled drawer.  
 
TUPB093 Compact 4 kW Variable RF Power Coupler for FRIB Quarter-wave Cavities 678
 
  • M.P. Kelly, Z.A. Conway, M. Kedzie, S.V. Kutsaev
    ANL, Argonne, USA
  • J.L. Crisp, L.L. Harle
    FRIB, East Lansing, Michigan, USA
 
  A new compact 4 kW power coupler has been designed and prototyped at Argonne National Laboratory in collaboration with Michigan State University. The coupler is intended for use on the β=0.085 80.5 MHz superconducting quarter-wave cavities for the FRIB driver linac and also for the planned ReA6 quarter-wave cavity cryomodule. The design has a cold RF window and a 3 cm variable bellows section. The 16 cm overall length of the RF window and bellows facilitates a simple and compact installation onto the cavity inside the clean room. A prototype have been cold tested with high power under realistic conditions at Argonne and results are presented.  
 
TUPB094 High Power Tests of TRASCO RFQ Couplers 681
 
  • E. Fagotti, L. Antoniazzi, F. Grespan, A. Palmieri, F. Scarpa
    INFN/LNL, Legnaro (PD), Italy
  • O. Brunasso Cattarello, R. Panero
    INFN-Torino, Torino, Italy
  • M. Desmons
    CEA/DSM/IRFU, France
 
  The 352.2 MHz 7.13 m long TRASCO RFQ requires an overall amount of 900 kW CW RF power in order to deliver the 40 mA proton beam from the initial energy of 80 keV to the final energy of 5 MeV. For such a purpose a system of eight compact (ϕext=38 mm, ϕint=19.4 mm) loop-based couplers was designed. In a first phase, only the first two (out of six) modules of the RFQ were tested at full power. Therefore only two (out of eight) couplers were used. In order to completely characterize these couplers, a dedicated test bench was prepared, consisting of a bridge waveguide and diagnostics (reflected power, vacuum, arc detectors etc.), onto which a couple of couplers was connected for transmission measurements. Each coupler was tested with a forward power of up to 140 kW. The description of the experimental setup and procedure, as well as the main results of the conditioning procedure will be reported in this paper.  
 
TUPB095 Design of Coupler for Direct Coupled Amplifier to Drift Tube Linac Cavities of the Injector RILAC2 for RIKEN RI Beam Factory 684
 
  • K. Suda, S. Arai, Y. Chiba, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
 
  A new linac RILAC2 was constructed at RIKEN RI Beam Factory as an injector for very heavy ions such as uranium and xenon of a high mass to charge ratio m/q  ∼  7, but high intensity ions can be extracted from an ion source. Three drift tube linac cavities, operate in continuous wave mode at 36.5 MHz, have been designed and built. In order to reduce an installation area, and to save a construction cost, we adopted a direct coupling method for a power amplifier without using a long transmission line. A complicated design procedure was performed in order to take into account a change of resonant frequency of the cavity caused by a capacitance of a power tube used in the amplifier. A design of the coupler, as well as the cavity was performed using a three-dimensional electromagnetic calculation code, CST Microwave Studio (MWS). The measured input impedance seen from the amplifier (700 – 1100 Ω) was reproduced well by the calculation of MWS. Also, in order to examine MWS, a case of a coupling with 50 Ω were calculated. The coupling conditions obtained by MWS were compared with the measurement and a calculation with a lumped circuit model.  
 
TUPB097 The C-band RF Pulse Compression for Soft XFEL at SINAP 687
 
  • C.P. Wang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
 
  A compact soft X-ray free electron laser facility is presently being constructed at shanghai institute of applied physics (SINAP), Chinese academy of science in 2012 and will be accomplished in 2014. This facility requires a compact linac with a high-gradient accelerating structure for a limited overall length less than 230 m. The c-band technology which is already used in KEK/Spring-8 linear accelerator is a good compromise for this compact facility and a c-and traveling-wave accelerating structure was already fabricated and tested at SINAP, so a c-band pulse compression will be required. AND a SLED type RF compression scheme is proposed for the C-band RF system of the soft XFEL and this scheme uses TE0.1.15 mode energy storage cavity for high Q-energy storage. The C-band pulse compression under development at SINAP has a high power gain about 3.1 and it is designed to compress the pulse width from 2.5 μs to 0.5 μs and multiply the input RF power of 50 MW to generate 160 MW peak RF power, and the coupling coefficient will be 8.5. It has three components: 3 dB coupler, mode convertors and the resonant cavities.  
 
TUPB108 Uppsala High Power Test Stand for ESS Spoke Cavities 711
 
  • R.A. Yogi, T.J.C. Ekelöf, V.A. Goryashko, L. Hermansson, M. Noor, R. Santiago Kern, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • D.S. Dancila, A. Rydberg
    Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
  • K.J. Gajewski, T. Lofnes, R. Wedberg
    TSL, Uppsala, Sweden
  • R.J.M.Y. Ruber
    CERN, Geneva, Switzerland
 
  The European Spallation Source (ESS) is one of the world’s most powerful neutron source. The ESS linac will accelerate 50 mA of protons to 2.5 GeV in 2.86 ms long pulses at a repetition rate of 14 Hz. It produces a beam with 5 MW average power and 125 MW peak power. ESS Spoke Linac consists of 28 superconducting spoke cavities, which will be developed by IPN Orsay, France. These Spoke Cavities will be tested at low power at IPN Orsay and high power testing will be performed at a test stand which will be set up at Uppsala University. The test stand consists of tetrode based RF amplifier chain at 352 MHz, 350 kW power and related RF distribution. Outputs of two tetrodes shall be combined with the hybrid coupler to produce 350 kW power. Preamplifier for a tetrode shall be solid state amplifier. As the spoke cavities are superconducting, the test stand also includes horizontal cryostat, Helium liquefier, test bunker etc. The paper describes features of the test stand in details.  
 
WE2A02 Solid State Marx Modulators for Emerging Applications 743
 
  • M.A. Kemp
    SLAC, Menlo Park, California, USA
 
  A class of intelligent, Marx-topology modulators are under development at SLAC. These modulators combine numerous advanced features that could be employed in any significant new HPRF installation. The talk will describe the design features and operational experience.  
slides icon Slides WE2A02 [1.117 MB]