X-Ray Thermoluminescence Dosimetry Characterization of Commercially Available CVD Diamond

High quality commercially available CVD diamonds are being tested in novel clinical high energy photons, hadron therapy, and high energy physics applications. In the present work, the authors report on the thermoluminescence (TL) and dosimetry properties of commercial synthetic CVD diamond sample from Element6, exposed to X-ray irradiation at dose rates of 3.9-120 Gy min(-1) from 0.13 to 90 Gy. The TL glow curves are composed of four peaks with maxima at about 104, 150, 210, and 280 degrees C and activation energies of 0.78, 0.79, 0.81, and 1.0 eV, respectively. The dose response of the area under TL glow curves is linear at doses lower than 0.6 Gy, supralinear between 0.6 and 6 Gy and sublinear at higher doses. The samples exhibited a strong TL fading of the low temperature 104 degrees C peaks that fades away around 120 min after irradiation, which is accompanied by increasing of the 210 and 280 degrees C peaks. The measured TL cycle reproducibility was very good, in spite of the fading exhibited by the lower temperature peak, with values of 0.1-3.0% at different dose rates and doses. It is concluded that CVD commercially single crystal electronic grade diamond may be securely used in clinical radiotherapy.