STUDY IN COMPUTATIONAL AND EXPERIMENTAL PHOTON ENERGY DEPENDENCE FOR CaSO4:Dy AND Al2O3:C MATERIALS

Tóm tắt

In this work, energy dependence of thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) for photon by the computational and experimental results was studied. Mass energy-absorption coefficients [in μen/ρ (cm2/g)] for calcium, sulfur, oxygen, aluminum, carbon and dysprosium using the Mathematica software were calculated. For materials composed of various elements, one may assume that the contribution of each element to the total interaction of the photon is additive “mixture rule”. The results obtained from the experiments and the computation were normalized to 137Cs energy response. Within method uncertainty, the calculated energy dependency shows a good agreement with experimental results. Both CaSO4:Dy powder (Made in Dalat Nuclear Reasearch Institute) and Al2O3:C dosimeters (InLight Basic, Landauer Inc., USA) showed very good uniformity, sensitivity, batch reproducibility, linearity and low fading for a wide range of doses. Choosing a correct energy for TLDs’ calibration is an important factor that can affect the accuracy of the absorbed dose. The results showed that TLDs and OSLDs have non-uniform response at different energies and both type of dosimeters are quite sensitive in the low photon energy region.