CVD Diamond Films For Radiation Detection

Diamond films produced by microwave plasma enhanced chemical vapor deposition (CVD) technique have been used to fabricate radiation detectors. The polycristalline diamond films have a measured resistivity of 1012 Ω.cm, a carrier mobility of 280 cm2/V.s and a carrier lifetime of about 530 ps. The detector response to laser pulses (λ = 355, 532 and 1064 nm), Xray flux (15 50 keV) and alpha particles (241Am, 5.49 MeV) has been investigated. The response speed of the detector is in the 100 ps range. A sensitivity of about 3 x 10–10 A/V.(Gy/s) was measured under 50 keV Xray flux. The detector current response to Xray flux is almost linear. It is also shown that CVD diamond detectors can be used for alpha particle counting.