Author: Friend, M.L.
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MOOB04 Upgrade of the Machine Protection System Toward 1.3 MW Operation of the J-PARC Neutrino Beamline 18
  • K. Sakashita, M.L. Friend, K. Nakayoshi
    KEK, Tsukuba, Japan
  • Y. Koshio, S. Yamasu
    Okayama University, Faculty of Science, Okayama City, Japan
  The machine protection system (MPS) is one of the essential components to realize safe operation of the J-PARC neutrino beamline, where a high intensity neutrino beam for the T2K long baseline neutrino oscillation experiment is generated by striking 30GeV protons on a graphite target. The proton beam is extracted from the J-PARC main ring proton synchrotron (MR) into the primary beamline. The beamline is currently operated with 485kW MR beam power. The MR beam power is planned to be upgraded to 1.3+ MW. The neutrino production target could be damaged if the high intensity beam hits off-centered on the target, due to non-uniform thermal stress. Therefore, in order to protect the target, it is important to immediately stop the beam when the beam orbit is shifted. A new FPGA-based interlock module, with which the beam profile is calculated in real time, was recently developed and commissioned. This module reads out signals from a titanium-strip-based secondary emission profile monitor (SSEM) which is placed in the primary beamline. An overview of the upgrade plan of the MPS system and the results of an initial evaluation test of the new interlock module will be discussed.  
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MOPB07 Beam Parameter Measurements for the J-PARC High-Intensity Neutrino Extraction Beamline 85
  • M.L. Friend
    KEK, Ibaraki, Japan
  Proton beam monitoring is absolutely essential for the J-PARC neutrino extraction beamline, where neutrinos are produced by the collision of 30 GeV protons from the J-PARC MR accelerator with a long carbon target. Continuous beam monitoring is crucial for the stable and safe operation of the extraction line high intensity proton beam, since even a single misfired beam spill can cause serious damage to beamline equipment at 2.5x1014 and higher protons-per-pulse. A precise understanding of the proton beam intensity and profile on the neutrino production target is also necessary for predicting the neutrino beam flux with high precision. Details of the suite of monitors used to continuously and precisely monitor the J-PARC neutrino extraction line proton beam will be shown, including recent running experiences, challenges, and future upgrade plans.  
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WEPC08 Optical System of Beam Induced Fluorescence Monitor Toward MW Beam Power at the J-PARC Neutrino Beamline 505
  • S.V. Cao, M.L. Friend, K. Sakashita
    KEK, Ibaraki, Japan
  • M. Hartz
    Kavli IPMU, Kashiwa, Japan
  • A. Nakamura
    Okayama University, Okayama, Japan
  A Beam Induced Fluorescence (BIF) monitor is being developed as an essential part of the monitor update toward MW beam power operation at the J-PARC neutrino beamline. By measuring the fluorescence light from proton-gas interactions, the BIF monitor will be used as a continuous and non-destructive diagnostic tool for monitoring the proton beam profile spill-by-spill, with position and width precision on the order of 200 µm. The main challenge lies in collecting a sufficient amount of fluorescence light for the beam profile reconstruction while controlling the beam-induced noise with the current beamline configuration. A study is presented with a particular focus on the optical system under development, which allows us to transport fluorescence light away from the high radiation environment near the proton beamline and detect the optical signal with a Multi-Pixel Photon-Counter-based fast readout.  
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