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Kondo, Y.

Paper Title Page
TUP049 Vane Machining by the Ball-end-mill for the New RFQ in the J-PARC Linac 518
 
  • T. Morishita, K. Hasegawa, Y. Kondo
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Baba, Y. Hori, H. Kawamata, H. Matsumoto, F. Naito, Y. Saito, M. Yoshioka
    KEK, Ibaraki
  
 

The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A numerical controlled machining with a conventional ball-end-mill has been chosen for the vane modulation cutting instead of the wheel shape cutter. In this presentation we will report the machining procedure, the results of the vane machining, RF properties, and some topics during the fabrication.

  
TUP050 Vacuum Brazing of the New RFQ for the J-PARC Linac 521
 
  • T. Morishita, K. Hasegawa, Y. Kondo
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Baba, Y. Hori, H. Kawamata, H. Matsumoto, F. Naito, Y. Saito, M. Yoshioka
    KEK, Ibaraki
  
 

The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A one-step vacuum brazing of a unit tank has been chosen to unite these four vanes together with the flanges and ports. In this presentation we will report the results of the vacuum brazing with the dimension accuracy and an RF property.

  
THP070 Simulation Study of the RF Chopper 911
 
  • Y. Kondo
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • M. Ikegami, F. Naito
    KEK, Ibaraki
  • J. Qiang
    LBNL, Berkeley, California
  
 

For the beam current upgrade of the J-PARC linac, a new RFQ (RFQ III)is developing. The peak beam current of RFQ III is 50mA. To increase the peak current from the existing RFQ (RFQ I), the longitudinal and/or transverse emittances are expected to be increased. However, the increase of the longitudinal emittance will affect the performance of the RF chopper system. In this paper, detailed simulations of the RF chopper system are described and the requirement for the longitudinal emittance of the RFQ is clarified.