Performance of CVD diamond alpha particle detectors

The inherent properties of diamond can, in principle, make it an ideal material for radiation detectors with interesting capabilities. We have fabricated a particle detector using a free-standing CVD diamond film with a thickness of 300 μm and area of 2 cm×2 cm and measured 5.5 MeV α spectra from an 241Am source. The I–V characteristics indicate that a fine Ohmic contact is formed between the CVD diamond and electrode. At the external electric field 10 kV/cm, the collection efficiency reaches an average value of 41%, corresponding to a charge collection distance (CCD) of about 259 μm and the energy resolution achieves 4.3%.