Linear-supralinear-sublinear beta-ray dose dependences of TL, OSL and afterglow in undoped CVD diamond

The thermoluminescence (TL), optically stimulated luminescence (OSL) and afterglow (AG) properties of chemical vapour deposition (CVD) diamond film irradiated by beta rays with doses from 0.5 to 1000 Gy have been studied. The film (23 µm) was grown for 47 h on monocrystalline silicon. The TL dose responses are similar for all the peaks and exhibit the typical linear–supralinear–sublinear behaviour. The supralinear growth starts at about 1.0 Gy and goes up to 100 Gy. At higher doses the dose responses go to saturation. The AG and OSL dose responses are similar to the TL one and exhibit the supralinear–sublinear behaviour. The linear part (if it exists) is not observed due to low AG and OSL intensity at doses lower than 2.0 Gy. The diamond film that had been irradiated with high doses, partially preheated and irradiated again with low test dose, exhibits increased TL, OSL and AG sensitivity that can be considered as a mixture of the supralinearity and sensitization. Pure sensitization is observed for the 350 and 400 K TL peaks and AG after preheating the sample to temperatures higher than 500 K. This sensitization gradually decreases from 10 to 1 as the preheating increases from 500 to 770 K.