Author: Satou, K.
Paper Title Page
TUOAB3 Development of Wide Dynamic Range Beam Loss Monitor System for the J-PARC Main Ring 1248
 
  • K. Satou, N. Kamikubota, T. Toyama, S. Yamada
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • S.Y. Yoshida
    Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
 
  The new beam loss monitor (BLM) system now in operation at the main ring of J-PARC consists of an isolated front-end current to voltage converter, a VME-based 24 bit ADC system. A dual detector system employs a proportional-type gas chamber (PBLM) and an air-filled ionization chamber (AIC). The system shows a wide dynamic range of 160 dB. It can detect the low level signal that would arise in the case of the detection of residual dose in the ring itself after the beam has been turned off as well as an event such as high level beam loss at the collimators. The signal rise time of the waveform obtained is 17 us which fast enough to meet the speed requirement of the Machine Protection System (MPS); which is that the MPS should dump the beam within 100 us when the beam loss signal exceeds the reference levels set in the ADC system.  
slides icon Slides TUOAB3 [2.692 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOAB3  
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THPVA010 Electron Cloud Simulations for the Main Ring of J-PARC 4436
 
  • B. Yee-Rendón, R. Muto, K. Ohmi, K. Satou, M. Tomizawa, T. Toyama
    KEK, Ibaraki, Japan
 
  The simulation of beam instabilities is a helpful tool to evaluate potential threats against the machine protection of the high intensity beams. At Main Ring (MR) of J-PARC, signals related to the electron cloud have been observed during the slow beam extraction mode. Hence, several studies were conducted to investigate the mechanism that produces it, the results confirmed a strong dependence on the beam intensity and the bunch structure in the formation of the electron cloud, however, the precise explanation of its trigger conditions remains incomplete. To shed light on the problem, electron cloud simulations were done using an updated version of the computational model developed from previous works at KEK. The code employed the signals of the measurements to reproduce the events seen during the surveys.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA010  
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