Growth and characterization of single crystal CVD diamond film based nuclear detectors

The deposition conditions and the detection properties of a homoepitaxial diamond film, grown by microwave Chemical Vapor Deposition (CVD) on a HPHT single crystal substrate are reported. The charge collection spectrum, measured under irradiation with a triple 239Pu 241Am 244Cm source emitting 5.16, 5.48 and 5.80 MeV α-particles respectively, shows three clearly resolved peaks with an energy resolution of about 1.1%. Both the charge collection efficiency and the energy resolution reach saturation values when the applied voltage exceeds 60 V, suggesting 100% collection efficiency. The detector was also tested with 14.8 and 14.1 MeV neutrons. The obtained collection spectra show a well separated 12C(n,α0)9Be reaction peak with an energy spread of 0.5 MeV for 14.8 MeV neutrons and 0.3 MeV for 14.1 MeV neutrons, which are fully compatible with the energy spread of the incident neutrons.