Calculated energy dependence of CaSO4 : Dy TL phosphor and phosphor embedded Teflon for X and gamma rays

The energy dependence of a CaSO4:Dy TL phosphor for 21 monoenergetic photon s of energy ranging from 0.01 to 3 MeV was calculated by using MCNP4A code. The calculation results show good agreement with those of other authors wi thin +/-5% relative error. Calculations and experiments are also performed to determine the energy dependence of CaSO4: Dy phosphor with Dy concentrat ions from 0.01 to 1.5 mol%, and with the compositions of TL-Teflon from 10 to 90 wt%. The calculated energy responses show good agreement with the exp eriment results within +/- 20% relative error except fora concentration low er than 0.1 mol% Dy and the low energy regions of M30 (Eave.= 20keV) and M6 0 (Eave.= 34keV). For the TL-Teflon mixture, the energy dependence shows an decreasing trend with the increase of Teflon concentration in MCNP calcula tion but shows no dependence for TL-Teflon mixture proportions in experimen t. These differences are due to the non-homogeneous distribution of Dy conc entration and the effect of large grain size in the phosphors. The energy d ependence of the 30 wt/o CaSO4 (0.1 mol%;Dy) and 70 wt/o Teflon that is pla ced behind the filters of plastic, aluminum, copper, tin and lead with a th ickness from 0.1 to 2 mm were calculated, respectively. (C) 2001 Elsevier S cience Ltd. All rights reserved.