Development of a synthetic diamond radiation detector with a boron doped CVD diamond contact

A boron doped CVD diamond contact was applied to a diamond radiation detector for suppressing a polarization phenomenon. A boron doped CVD diamond layer was grown on a synthetic type IIa single crystal diamond; it was then used as a contact. The contact was completely free from radiation damage which is unavoidable in a contact made by an ordinary ion implantation technique. An energy resolution of 0.39% for 5.486 MeV α particles was achieved. A steady counting rate higher than 50 cps for α particles was confirmed by the developed detector. It is proposed that the boron doped CVD diamond contact functioned as a blocking contact on this detector.