Thermoluminescence analysis of β- and γ-irradiated chemical vapour deposited diamond films

The thermoluminescent (TL) response of a set of synthetic diamond films obtained by chemical vapour deposition was investigated using gamma and beta radioactive sources over the dose range from 60 mGy to 3.5 Gy. A TL response linear with dose was generally observed. A numerical curve-fitting procedure was applied to deconvolute the complex-structured TL glow curves, which were found to be composed at most by five peaks in the temperature range between 25 degrees C to 400 degrees C. A short preheat treatment after irradiation allowed us to obtain a very stable smooth-shaped glow curve composed of a unique peak close to 300 degrees C. This isolated structure followed first-order kinetics over the whole dose range. The activation energy of the main peak, approximate to 1 eV, was determined considering all samples and all irradiation doses using both the peak shape method and the fitting procedure. The corresponding frequency factor was estimated to be within the range 10(7)-10(9) s(-1). The TL sensitivity of the diamond films calculated considering the isolated high-temperature peak compares favourably with that measured with a set of LIF TLD100 and TLD700 standard dosimeters.