Author: Michizono, S.
Paper Title Page
WEPPD050 Upgrade of the RF Reference Distribution System for 400 MeV LINAC at J-PARC 2630
 
  • K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
    KEK, Ibaraki, Japan
  • F. Sato, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
 
  In J-PARC, the accelerator systems are controlled using the 12 MHz master clock in center control building. In the present J-PARC Linac, the negative hydrogen is accelerated by 181 MeV using the RFQ, DTLs, and SDTLs which have the resonance frequency of 324 MHz. The low-level radio frequency (LLRF) system is based on the reference signal of 312 MHz (LO) synchronized with the master clock. We are planning to upgrade Linac by the accelerated energy to 400 MeV by the installation of ACS cavities with the resonance frequency of 972 MHz. Then, not only 312 MHz but also 960 MHz reference signals are necessary. Therefore, a new RF reference signal oscillator was installed at J-PARC LINAC. The phase noise of the output signal in this module was measured by the signal source analyzer. The jitter of the output signal, which was estimated from the integration of phase noise from 10 Hz to 1 MHz, becomes about 40 fs and was two order smaller than that of the old system (about 1700 fs) by the installation of new oscillator and the optimization of the path of the master clock. It can be expected to improve the operating ratio in J-PARC LINAC.  
 
TUPPR005 Linac Upgrade in Intensity and Emittance for SuperKEKB 1819
 
  • T. Higo, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
    KEK, Ibaraki, Japan
  • D. Satoh
    TIT, Tokyo, Japan
 
  The SuperKEKB is designed to produce 40 times luminosity than that of the KEKB. In order to realize such a high luminosity, the injector linac should provide both electron and positron beams of about 4-5 nC/bunch, which is several times higher than before. In addition, their emittance requirement of the injection beam to the rings is 20 microns, which is a factor of a few tens smaller than before. The intensity and emittance of the electron beam are realized directly by developing the photo RF gun. In contrast, the positron intensity is increased by adopting a higher capture efficiency system with flux concentrator followed by large-aperture accelerators, while its emittance is reduced by a damping ring. For preserving such a low emittance of both beams toward the injection to the rings, the suppression of the emittance growth is crucial. To this end, the alignment of the accelerator components should be a few tens of microns, where we need an improvement by more than a factor 10. The beam-based alignment is definitely needed with better-resolution BPMs. In the present paper are reviewed the overall progress and perspective of the design and the associated component developments.  
 
THPPC009 Investigation of the Approaches to Measure the RF Cable Attenuation 3290
 
  • K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
    KEK, Ibaraki, Japan
  • F. Sato, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
 
  In the accelerator facilities, many RF cables are used for the various purposes such as the transmission system and the cavity monitor. The knowledge of the power attenuation in those cables is important role to control RF. In general, the cable attenuation is measured from S parameters to use a network analyzer. However, the control system is located far from the place of the cavities, and it difficult to measure by a network analyzer. Then we investigated other methods to measure the RF cable attenuation.