Influence of temperature on the response of diamond radiation detectors

The response of chemically vapor deposited diamond detectors under alpha pa rticle irradiation was studied as a function of operating temperature in th e 20-280 degreesC range. The detector characteristics were studied for two initial states: (i) the detector being either preirradiated under x-rays at a dose of 8 Gy (pumped state) or (ii) preannealed at 400 degreesC for 15 m in (depumped state). Pumped detectors were found to exhibit a stable respon se (evaluated by measurement of the charge collection efficiency eta) with temperature up to 120 degreesC, above which a decrease of eta was observed. Preannealing at 400 degreesC was shown to induce, at room temperature, a d rastic deterioration of the detector response, when compared to that of pum ped devices, whereas above 150 degreesC a reversed trend was observed. Corr elations between the response of the diamond detectors and the presence of traps were determined by comparing the detector response for alpha particle s with the thermally stimulated current (TSC) spectrum. The temperature dep endence of the detector response was shown to be related to the presence of a trapping level measured around 260 degreesC by TSC. (C) 2001 American In stitute of Physics.