Characterisation of a coplanar CVD diamond radiation detector

Studies have been made of the performance of polycrystalline CVD diamond fo r use as a radiation detector in high temperature or high radiation environ ments. In this work, we have fabricated a coplanar CVD diamond detector con sisting of inter-digitated metal electrodes deposited only on the 'growth' side of the diamond film. This device geometry produces lateral electric fi eld distributions close to the growth surface of the film, where the diamon d crystallites are significantly better ordered and largest in size. Pulse height spectra were acquired using a Am-241 alpha particle source which sho wed a broad full-energy peak corresponding to a charge collection efficienc y of approximately 15%. The X-ray response of the detector was also measure d using a silver anode X-ray generator. The observed photocurrent showed a slow time evolution before reaching a steady value, indicating the presence of significant charge traps in the material. The measured sensitivity of t he detector to 30kV((peak)) X-rays was 2.1 x 10(-5)C/Gy. (C) 2001 Elsevier Science B.V. All rights reserved.