Study of the Thermoluminescence of CVD Diamond

This work reports some thermoluminescent properties of chemical vapour deposition diamond film grown by 5 kW microwave assisted plasma chemical vapour deposition. The 2" diamond sample with the thickness of 32 μm was exposed to gamma radiation in the dose range 0.6-55 Gy. The thermoluminescent glow curve of diamond sample displayed a peak with the maximum centered at 240°C. The linearity of the detector response in the range of 10-55 Gy was observed. The bleaching effect, seen as fading of the thermoluminescent signal when the device was exposed to light in the visible range, was also noticed. Two-dimensional dose distribution was measured using 2D thermoluminescent reader equipped with a sensitive 640 × 480 pixels charge coupled device camera. The surface morphology of the diamond film was observed with scanning electron microscope and atomic force microscope. The grain size was estimated as about 15 μm. The Raman spectroscopy was used to characterize phase purity. The width and position of the diamond Raman band around 1332 $cm^{-1}$ indicated that the coating is crystalline and of good quality. It is concluded that good quality chemical vapour deposition diamond coating could be promising material for thermoluminescent dosimetry.