CVD diamond for medical dosimetry applications

Diamond is potentially a very suitable material for use as a radiation dosimeter; the wide band gap results in low dark currents and low sensitivity to visible light, the high carrier mobilities can give rapid response, the very high density of strong bonds in the crystal structure make diamond very resistant to radiation damage and it is tissue equivalent. Recent advances in the synthesis of polycrystalline diamond by chemical vapour deposition (CVD) techniques have allowed material with electronic properties suitable for dosimetry applications to be consistently produced. This paper reports on simple dosimeters which have been fabricated from CVD diamond plates with Cr–Au electrodes in a sandwich configuration. The performance of the devices is compared with a silicon diode dosimeter and a commercial natural diamond dosimeter in tests using 250 kV X-rays from a clinical source.