Author: Nanmo, K.
Paper Title Page
TUPB099 Input Coupler of the J-PARC DTL 690
  • F. Naito, K. Nanmo, H. Tanaka
    KEK, Ibaraki, Japan
  • K. Hirano, T. Ito
    JAEA/J-PARC, Tokai-mura, Japan
  Each tank of J-PARC DTL has two input couplers. The coupler has a movable coupling loop with an capacitive element which increase the coupling with the tank. The loop position is the outside of the tank, where is the atmosphere. The tank vacuum is kept by the ceramic window on the wall for the coupler port. The ceramic is made of Aluminum oxide of 99.7 % purity. RF properties and the mechanical structure of the coupler were designed adequately in order to achieve the desired performance. We will report the design of the coupler in detail and the experiences for the practical operation of the DTL.  
TUPB100 Recovery and Status Report of DTL/SDTL for the J-PARC After Earthquake 693
  • T. Ito, K. Hirano
    JAEA/LINAC, Ibaraki-ken, Japan
  • F. Naito, K. Nanmo
    KEK, Ibaraki, Japan
  The J-PARC facilities had big damages because of the earthquake on March 11, 2011. The J-PARC linac in the tunnel had also damages. For instance the alignment of the cavity was deformed more than 40 mm and there had been observed about 0.2 mm in horizontal direction for a few DTs in the DTL. However, as the result of the recovery work which includes the re-alignment and re-conditioning of whole cavities, we were able to restart the beam acceleration of the linac. The stability of the DTL and SDTL has returned to the state before the earthquake except for a few tanks of SDTL. In this paper, we will present the recovery works from the earthquake and the operating status of the DTL and the SDTL.  
TUPB101 Beam Loss Occurred at DTL Cavity in J-PARC Linac 696
  • A. Miura, K. Hirano, T. Ito, T. Maruta
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Ikegami
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Miyao, F. Naito, K. Nanmo
    KEK, Ibaraki, Japan
  The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.