Keyword: neutron
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TUAL02 A New Beam Loss Monitor Concept Based on Fast Neutron Detection and Very Low Photon Sensitivity detector, photon, simulation, electron 277
  • J. Marroncle, A. Delbart, D. Desforge, C.L.H. Lahonde-Hamdoun, Ph. Legou, T. Papaevangelou, L. Segui, G. Tsiledakis
    CEA/IRFU, Gif-sur-Yvette, France
  Superconductive accelerators may emit X-rays and Gammas mainly due to high electric fields applied on the superconductive cavity surfaces. Indeed, electron emissions will generate photons when electrons impinge on some material. Their energies depend on electron energies, which can be strongly increased by the cavity radio frequency power when it is phase-correlated with the electrons. Such photons present a real problem for Beam Loss Monitor (BLM) systems since no discrimination can be made between cavity contributions and beam loss contributions. Therefore, a new BLM is proposed which is based on gaseous Micromegas detectors, highly sensitive to fast neutrons, not to thermal ones and mostly insensitive to X-rays and Gammas. This detector uses Polyethylene for neutron moderation and the detection is achieved using a 10B or 10B4C converter film with a Micromegas gaseous amplification. Simulations show that detection efficiencies > 8 % are achievable for neutrons with energies between 1 eV and 10 MeV.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUAL02  
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WEPG59 Thermal Simulations of Wire Profile Monitors in ISIS Extracted Proton Beamline 1 simulation, proton, target, electron 785
  • D.W. Posthuma de Boer, A. Pertica
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  Wire scanners and secondary emission (SEM) grids are used for measurements of transverse beam profile at the ISIS neutron and muon source. Silicon carbide-coated carbon fibre wires are used in profile monitors throughout the ISIS accelerator. One such SEM grid is currently installed close to the target in EPB2 and is intercepted by the 800 MeV proton beam at a repetition rate of 10 Hz. Future profile measurements will require another of these monitors to be installed close to the target in EPB1; intercepted with a repetition rate of 40 Hz. Wires intercepting the ion beam are heated due to the deposition of beam-energy. Thermal simulations for the higher repetition rate were performed using ANSYS and a numerical code. The numerical code was then expanded to include various beam, wire and material properties. Assumptions for temperature dependent material emissivities and heat capacities were included in the simulation. Estimated temperatures due to the energy deposited by protons, and approximate values of deposited energy from the expected neutron flux are presented. The effects on wire-temperature of various beam and wire parameters are also discussed.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG59  
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