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For the IFMIF-EVEDA project, a prototype accelerator is being built in Europe and installed at Rokkasho (Japan). It is designed to accelerate 125 mA CW Deuteron to 9 MeV. The very high space charge and high power (1.125 MW) of the beam make this accelerator very challenging. For hands-on maintenance requirements, losses must be well less than 1W/m, i.e. 10-6 of the beam. That is why, in the 5-9 MeV superconducting Linac, beam dynamics physicists search to tune the beam by minimizing the very external part of the halo. The need is thus to be able to measure very tiny beam losses, called μ-losses, at all the focusing magnets. Only neutrons and γ exit from the beam pipe due to the low deuteron beam energy. Thus such beam loss detectors have to be sensitive to neutrons, but rather insensitive for X-rays and γ to decrease their contributions coming from super-conducting cavity emission. They must be radiation hardness qualified, and capable to work at cryogenic temperature. Single CVD diamonds (4×4×0.5 mm3) are studied for these purposes and first results seem to fulfill the requirements up to now.
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