Proton Detection in MAST-U using Silicon and Diamond Surface Barrier Detectors

A silicon based surface barrier detector (SSB) array has previously been used at MAST (Perez et al.) to detect unconfined energetic 3MeV fusion protons. In a tokamak environment detector heating can strongly affect the energy resolution and detection efficiency.  To study these we have used an Am-241 α particle source to evaluate the behavior of a Si-based SSB detector with an active area of 50 mm² and a depletion depth of 300 μm and a diamond detector with an active area of  3 mm² and  100 μm depletion depth over a temperature range of up to 50^oC. Both types of detectors will be installed in MAST-U and first results will  be shown if available. The diamond detectors are planned to be used in 

a new version of the PD array consisting of six channels. Is it expected that a diamond PD-array will avoid the degradation that was previously found in some SSB detectors and be able to operate in future longer MAST-U pulses.