Studies on the application of CVD diamonds as active detectors of ionising radiation

Abstract

Due to its tissue-equivalence, radiation hardness, resistivity to chemicals and thermal stability, diamond is becoming an interesting material for developing dosimeters of ionising radiation. Several types of CVD diamonds grown at the Institute for Materials Research at the Limburg University, Belgium, were used to construct detectors working in ionisation chamber mode, applicable in medical physics. CVD diamonds with substrate removed, cut into 3 mm x 3 mm x 0,8 mm pieces and with deposited Au contacts, exposed in an external field of 320 kVp X-rays demonstrated sensitivity which varied from 50 to 630 nC/Gy, and a sublinear response with dose rate. A pencil-shaped holder was developed and used for testing the diamond detectors. The main deficiency of the system so far are extended periods required to reach signal saturation and recovery after irradiation. We expect this deficiency to be overcome by improving the quality of CVD diamonds. (C) 2001 Elsevier Science B.V. All rights reserved.