CVD Diamond X-ray Detectors for Radiotherapy Dosimetry
X-ray detectors were fabricated from a range of commercially-available synthetic diamond fabricated using chemical vapour deposition (CVD). As these detectors are intended as dosimeters for use in radiotherapy (beam calibration and profiling, in-situ dose measurements etc.), they were appropriately packaged and tested in a clinical environment, using clinical apparatus and following clinical procedures. The combination of linear dose-rate dependence of the photocurrent, negligible dark current levels (pA or less, compared to nA photocurrents), low priming doses (few Gy) and high specific sensitivities (of up to 460 nCGy-1mm-3, compared to reported values of 50–140 nCGy-1mm-3 for a commercial natural diamond-based X-ray detector) demonstrates the potential of these devices as simple–to–use, small size, tissue-equivalent, sensitive X-ray dosimeters.