Abstract
Thermoluminescence (TL) of CaSO4:Dy phosphor, irradiated by 48MeV Li-7 ions with different fluences in the range 1 x 10(9)-5 x 10(11) ions cm(-2) has been studied. The samples from the same batch were also exposed to gamma-rays from a Co-60 source for comparative studies. The TL glow curve of the material, irradiated with the ion beam has a simple structure with a prominent peak at around 494 K along with three small shoulders at around 424, 592 and 662 K. The TL saturation has been observed at around the fluence 1 x 10(11) ions cm(-2). As the fluence is increased from 1 x 10(9) to 5 x 10(11) ions cm- 2, a shift in the peak positions towards the lower temperature side, by around 7 K was observed. However, with increasing fluence, the TL glow curve structure remains invariant with no change in the relative intensities between the 494 and 424 K peaks, while in the case of gamma-irradiated samples, in contrast, the intensity ratios of these peaks increase exponentially with exposures. Theoretical analysis of the glow curves of the ion beam and gamma-irradiated samples was done by the glow curve deconvolution method. The efficiency of CaSO4 : Dy to 48MeV(7)Li ions has been measured relative to gamma-rays of Co-60 and found to be 0.81. This result, along with the observed good linearity over a large span of fluences, shows that this phosphor is quite suitable as a dosimeter for heavy charged particles.