ساخت دزیمتر EPR نانوبلور استرانسیوم سولفات آلاییده با دیسپرسیوم و بررسی خواص دزیمتری آن

The dosimetric characteristics of γ-radiation induced defects in strontium sulfate rod dosimeter were investigated using electron paramagnetic resonance (EPR) technique focusing on the dose range of 10–15000 Gy. The most significant EPR signals of spectroscopic splitting factor (g-value) g=2.0036 ، g=2.0090 and g=2.0160 were observed and attributed respectively to the SO4¯, SO3¯ and O3¯ peaks, which were created by gamma radiation. The intensity of the signals increases linearly with increasing absorbed doses up to 10000 Gy. In this research, nano-crystalline of SrSO4:Dy, SrSO4:Tb and SrSO4:Dy&Tb with grain sizes of 45–55nm has been prepared by the co-precipitation method. EVA and paraffin wax were selected as binding materials for strontium sulfate. It was not observed any interferences or noises in the EPR signal. The spectrum of SrSO4 with different dopants and concentrations were compared. The results showed that SrSO4 doped with 0.2 mole % dysprosium has high intensity. Then it was chosen for comparing with pure SrSO4. The intensity of SO4¯, SO3¯ and O3¯ peaks in the dosimetry range 10-15000 Gy for both EPR dosimeters of pure SrSO4 and SrSO4: Dy (0.2%mol) were compared. The obtained results revealed increase in sensitivity and dosimetry range of SrSO4:Dy (0.2%mol) by factors of three and ten, respectively.