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Asano, H.

Paper Title Page
MOPEC066 Status of Mass Production of the ACS Cavity for the J-PARC Linac Energy Upgrade 618
 
  • H. Ao, K. Hirano, T. Morishita
    JAEA/LINAC, Ibaraki-ken
  • H. Asano, N. Ouchi, N. Tsubota
    JAEA/J-PARC, Tokai-mura
  • K. Hasegawa
    JAEA, Ibaraki-ken
  • F. Naito, K. Takata
    KEK, Ibaraki
  • V.V. Paramonov
    RAS/INR, Moscow
  • Y. Yamazaki
    J-PARC, KEK & JAEA, Ibaraki-ken
 
 

The mass production of the ACS (Annular Coupled Structure) cavity started from March 2009 for the J-PARC Linac energy upgrade from 181 MeV to 400 MeV. This upgrade project requires 18 ACS accelerating modules and two debunchers additionally within three years. The construction schedule is so tight that we have to optimize the fabrication process. For example the geometrical beta is varied for each accelerating module, thus the several test cells were fabricated and for the all beta before the mass production to confirm the initial design and the frequency tuning procedure. This paper describes our approach for the mass production and the current status and results.

 
TUPEA046 LLRF Controller Upgrade for the J-PARC 400 MeV LINAC 1434
 
  • Z. Fang, S. Anami, Y. Fukui, M. Kawamura, C. Kubota, S. Michizono, F. Naito, K. Nanmo, S. Yamaguchi
    KEK, Ibaraki
  • H. Asano, K. Hasegawa, T. Itou, T. Kobayashi, S. Shinozaki, N. Tsubota
    JAEA/J-PARC, Tokai-mura
  • E. Chishiro, H. Suzuki
    JAEA, Ibaraki-ken
 
 

The output energy of the J-PARC LINAC will be upgraded from 181 to 400 MeV in the next two years by adding high-beta acceleration sections. The upgrade of the FPGA-based digital LLRF controller for the 400 MeV LINAC will be presented in this paper. The new LLRF control system works for both the 324 MHz low-beta and 972 MHz high-beta sections. Many functions are added into the LLRF controller, such as 1) working for different RF frequencies, 2) gradually increasing the feedback gains in the feedback loop instead of fixed ones, 3) automatic chopped-beam compensation, 4) automatically switching the beam loading compensation in accordance with the different beam operation mode, 5) input rf-frequency tuning carried out by a FPGA to match the rf cavities during the rf start-up, 6) auto-tuning of the rf cavity tuner by detecting the phase curve of the rf cavity during the field decay instead of the phase difference between the cavity input and output signals.

 
THPEB047 The Development of L-band Inductive Output Tube without Trolly toward Higher Applied Voltage. 3984
 
  • M. Yoshida, S. Fukuda
    KEK, Ibaraki
  • H. Asano, M. Kubosaki, Y. Moriguchi
    Mitsubishi Electric Corp., Communication Systems Center, Amagasaki City, Hyogo
 
 

The L-band inductive output tube (IOT) without trolly was developed to operate under higher applied voltage. The operation frequency of conventional IOTs is tuned using its trolly. This mechanism is based on the lower frequency IOT. However it causes less insulation voltage of the ceramics since the electric insulation oil is not available for its trolly and the length of the insulation ceramics is limited because it is a part of the resonant cavity. In case of IOTs, it is important to increase the applied voltage for higher output power since the grid gap is very narrow and its area cannot be increased to keep the gain. Thus we developed an IOT which has a longer insulating ceramic and the input cavity is filled with vacuum to use the electric insulation oil. Further the dielectric waveguide can solve to feed the input microwave to the cathode grid without trolly. These new features of the IOT is very effective for the fixed frequency application such as the accelerator, for example the energy recovery linac. The design and the experimental results will be presented in this report.