Modeling the thermoluminescent response of CaSO4:Dy by MCNPX method

Full text: Dysprosium doped calcium sulfate (CaSO4:Dy) phosphors are widely used for gamma radiation dosimetry. A calibration system to field application is done for each type application. Therefore, calibration of the TL phosphors against of gamma radiation is not sufficient for relating the TL readout to absorbed dose or to quantities relevant in radiation protection, without suitable correction. In this work presents the simulated results of CaSO4:Dy after gamma irradiated. In order to study the photon interaction in the matter, a cylindrical model of 1 cm3 was used. The gamma radiation source was placed at 1 m to object, the source is considered as an isotropic source of 60Co. The energy deposited into cylindrical model was determined by the Monte Carlo Neutron Particle (MCNPX) method. The CaSO4:Dy phosphor used in this investigation were considered as nanopowder form. In order to simulate the distribution energy into cylindrical volume model filled completely nanosize particles CaSO4:Dy. Measurements of the TL phosphors were obtained by irradiating of the powder under gamma radiation. TL glow curve of CaSO4:Dy after gamma irradiated at a 1 Gy of absorbed dose was obtained. In the future work TL response as a function of grain size will be determined using the MCNPX method and its will correlated with thermoluminescence efficiency