Author: Fujita, T.
Paper Title Page
MOPMB028 Development of Beam Diagnostic System for the SPring-8 Upgrade 149
 
  • H. Maesaka, T. Ohshima, Y. Otake
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • H. Dewa, T. Fujita, K. Kobayashi, M. Masaki, S. Matsubara, T. Nakamura, S. Sasaki, S. Takano
    JASRI/SPring-8, Hyogo-ken, Japan
 
  The goal of the beam diagnostic system for the SPring-8 upgrade is to deliver brilliant X-rays enabled by the new low-emittance ring to experimental stations with ultimate stability. Developments of accurate electron and photon beam position monitors (EBPM and XBPM, respectively) with both short and long-term stability are the most critical. The EBPM sensitivity is also crucial for low-current beam commissioning to accomplish the first beam storage in the ring. We designed a button electrode to obtain sufficiently high-intensity signals while suppressing high-Q trapped modes leading to impedance and heating issues. We also designed a precise EBPM block and a rigid support to achieve mechanical accuracy and stability. Another challenge is the development of a reliable and stable XBPM, which should be an accurate reference for an orbit feedback without any photon-energy dependences. A significant improvement of a blade-type XBPM or an invention of a novel XBPM detecting the core of an intense X-ray beam are necessary. The other diagnostic instrumentations can be utilized for the new ring with minor improvements.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB028  
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MOPMW009 RF System of the SPring-8 Upgrade Project 414
 
  • H. Ego, T. Fujita, N. Hosoda, K. Kobayashi, T. Masuda, S. Matsubara, T. Sugimoto
    JASRI/SPring-8, Hyogo-ken, Japan
  • T. Asaka, T. Fukui, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
 
  The RF system of the SPring-8 storage ring has stably generated an accelerating voltage of 16 MV at a frequency of 508.58 MHz since 1997. In the upgrade of the SPring-8, a beam energy is lowered from 8 to 6 GeV and a needed voltage is 7 MV. The upgrade employs multi-bending optics, and shortens the straight sections available for RF accelerating cavities by 30%. On account of the space, the RF system is to be so rearranged that the number of cavities can be reduced to half. The analog low-level RF (LLRF) system in use controls the voltage with sufficiently small deviations of less than 0.1 % in amplitude and less than 0.1 degree in phase, but becomes out-of-dates and hard to be maintained. We plan to replace them with a compact digital LLRF system in the MTCA.4 standard and based on under-sampling scheme. The SACLA linac is used for injecting a low-emittance beam to the ring. Because we have to balance the FEL operation and the beam injection on demand, pulse-by-pulse control of beam parameters is going to be implemented to the SACLA LLRF modules. Furthermore, we build a timing system for injection to a target bucket-position in the ring within a time deviation of 3 ps.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW009  
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