Synthetic CVD diamond, being non-toxic and tissue equivalent, has been proposed as a ionizing radiation passive dosimeter with relevant applications in radiotherapy and clinical dosimetry. In the present work, the thermoluminescence (TL) properties of microwave-assisted chemical vapor deposition (MWCVD) diamond, 6m thick film grown on (100) silicon substrates, were studied after room temperature -irradiation for 2.4, 3.1, 5.94, 13.1, 20.67, 43.4 and 81.11Gy min-1 dose rates in the range of 0.05-10kGy. At fixed irradiation dose the TL efficiency increases as the dose rate increases. As the dose increases the peak temperature at the maximum intensity of the TL glow curve is shifted about 10K degrees toward the lower temperature side. The TL glow curve shape resembles first-order kinetics for low-radiation doses and second-order kinetics for higher doses. Linear dose behavior was found for doses below 200Gy and supralinear for higher doses; respectively, with a significant dependence on the dose rate, reaching saturation for higher doses around 2.0kGy. Due to the dose rate dependence of the TL properties of the CVD diamond sample, it is necessary to take these effects into consideration for dosimetric applications involving synthetic CVD diamond.
Bibliographical noteFunding Information:
The authors are indebted to Dr. B. Gan for growing the samples and Prof. C. Furetta for enthusiastic and enlightening discussions. We acknowledge financial support from the Oficina de Colaboración Interinstitucional UNAM, SEP and Conacyt grants No. 36521, 37641 and 32069.
- CVD diamond films
- Dose rate effects
- Gamma radiation