Characterisation of scCVD diamond detectors with γ sources

A single-crystal CVD (Chemical Vapor Deposition) diamond detector was used to measure γ rays in order to assess its performance in terms of energy resolution and linearity. For this purpose, 57Co, 133Ba, 22Na, 207Bi and 137Cs γ sources were used. Electrons scattered by the backward Compton process were detected in the diamond, in coincidence with (backscattered) γs measured in a NaI detector, placed at 180° from the CVD diamond detector with respect to the source. The resulting calibration shows a linear dependence of the charge deposited in the diamond and a resolution of about 24 keV FWHM for the energy of the incident γs between 40 keV (57Co) and 477 keV (137Cs), comparable with the resolution of our electronic chain.