CVD DIAMOND TIPS AS X-RAY-DETECTORS

Diamond is a very attractive material for use as a radiation detector due to its inertness, radiation hardness and tissue equivalence. The d evelopment of diamond radiation detectors was limited by the availabil ity of good and reproducible natural samples. The advent of chemical v apour deposition techniques has allowed these drawbacks to be overcome and applications of CVD diamond in X-ray and nuclear dosimetry to be explored by several researchers. In this paper, we report the fabricat ion and characterisation of miniaturised (0.1 mm(3)) X-ray detectors m ade from polycrystalline diamond films (10/20 mu m thick) deposited by hot filament vapour deposition technique on metallic (tungsten) 300-m u m-diameter tips. The detector response to X-ray flux produced by an X-ray generator with peak energies ranging from 50 to 250 keV and by e lectron linear accelerator used in radiotherapy with a peak energy of 6 MeV has been investigated. The linearity and the sensitivity of the detector as a function of dose rate at different photon energies has b een evaluated, and the collection length has been estimated by analysi ng the behaviour of the photocurrent as a function of the applied bias voltage. (C) 1998 Elsevier Science S.A.