Author: Matsumoto, H.
Paper Title Page
MOPWA004 Development of a Non-inductive Ceramic Resistor 669
  • T. Sugimoto, K. Fan, K. Ishii, H. Matsumoto
    KEK, Ibaraki, Japan
  • K. Abe
    Hitachi Haramachi Electronics Co. Ltd., Hitachishi, Ibaraki, Japan
  • S. Fukuoka
    University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
  Non-inductive ceramic resistors, based on alumina and carbon, are used for impedance matching in the circuit of the J-PARC main ring injection kicker system. The kickers were installed in December 2011, and have been in operation successfully since then. However, discharges at the edge of the ceramic bulk were observed after several weeks’ operation, which increase resistance from O(100) to O(1M). Investigation indicates that poor contact with the rough surface of the ceramic bulk due to irregular shaped spots causes micro-gaps, which trigger the discharge. In order to improve the contact, one type of brazing technology has been experimentally applied to one resistor. Another resistor had an annealed thin copper plate inserted, and both resistors were tested and compared. In this paper, we will describe details of the development of the resistors and give future prospects.  
MOPWA009 Development of a Fast Compensation Kicker System for J-PARC Main-ring Injection 684
  • S. Fukuoka
    University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
  • K. Fan, K. Ishii, H. Matsumoto, T. Sugimoto
    KEK, Ibaraki, Japan
  Injection system of J-PARC main ring employs four lumped kickers to deflect the incoming beam. The residual field caused by tail and reflection of excitation current increases the closed beam orbit leading to particle loss in high power operation. A correction method using a fast kicker system to compensate the remaining angle is being developed. Doe to the narrow bunch spacing, transmission line kicker is selected to satisfy requirements of fast rise and fall time. The kicker magnet uses ceramic capacitors instead of parallel metal plates to make the magnet compact and reduce the stray inductance. Capacitors are installed in vacuum chamber. A very thin core is used to reduce distributed inductance. A bandwidth is calculated as 160 MHz. A Marx generator using FET switches has been studied, which is able to produce fast rise and fall time as 50 ns. Any pulse shape is generated by choosing switches to fire. A prototype magnet and a power supply have been fabricated for parameters test. In this paper, we will report the details of the system design, analyze the measurement results and give future prospects.  
WEPEA016 Upgrade Study of JPARC Main Ring Fast Extraction Septa System 2531
  • K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Morita
    KEK, Ibaraki, Japan
  The JPARC main ring fast extraction (FX) system has two functions, deliver high power beam to the neutrino experimental facility and dump the beam at any time in case of hardware failures. The present FX system consists of five pair of bipolar kickers and eight pair of bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, the conventional multi-turn low-field septa will be replaced by eddy current type septa. Several configurations of the new design has been studied to realize the requirements of thinner septum, higher field quality, lower leakage and higher mechanical stability. To provide sufficient flat top field for the FX beam, superposition of 3rd harmonic pulse has been employed.  
WEPFI045 PAL-XFEL Accelerating Structures 2806
  • H.-S. Lee, H. Heo, J.Y. Huang, W.H. Hwang, S.D. Jang, Y.D. Joo, H.-S. Kang, I.S. Ko, S.S. Park, Y.J. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
  • I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • H. Matsumoto
    KEK, Ibaraki, Japan
  • S.J. Noh, K.M. Oh
    Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea
  We need 172 accelerating structures for the PAL-XFEL 10 GeV main linac. It takes long time for these structures to be delivered. So we are trying to find suppliers of the accelerating structures. First, we made an order of 40 accelerating structures to Mitsubishi Heavy Industry (MHI), which have Quasi-type couplers to reduce the quadruple and sextuple components of the electric field in the coupling cavity. And Research Instruments (RI) has fabricated a 3m long race type accelerating structure for PAL-XFEL. Also, Vitzrotech which is a domestic company and IHEP in China are under developing accelerating structures for PAL-XFEL respectively. We will describe the current status of accelerating structures and high power test results of the newly developed structures in this paper.