THERMOLUMINESCENCE ANALYSIS OF BETA-IRRADIATED AND GAMMA-IRRADIATED CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS

The thermoluminescent (TL) response of a set of synthetic diamond film s 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 c urve-fitting procedure was applied to deconvolute the complex-structur ed TL glow curves, which were found to be composed at most by five pea ks in the temperature range between 25 degrees C to 400 degrees C. A s hort preheat treatment after irradiation allowed us to obtain a very s table 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, approxim ate to 1 eV, was determined considering all samples and all irradiatio n doses using both the peak shape method and the fitting procedure. Th e 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 wit h that measured with a set of LIF TLD100 and TLD700 standard dosimeter s.