ESR studies to elucidate the origin of the RPL emission of undoped-CaSO4

Recent research has shown that CaSO4, without any intentional addition of impurities, exhibits remarkable radiophotoluminescence (RPL) properties. However, the origin of the RPL in CaSO4 has yet to be fully understood. ESR measurements were carried out to identify the defect species responsible for RPL and elucidate the luminescence's origin. ESR measurements on undoped-CaSO4 with different radiation sensitivities showed SO4-, SO2-+SO3-, PO42-, Si=O-3 in P2O5-SiO2 (E' center), Al2O3 hole center and Mn2+ defect species in CaSO4. This means that CaSO4 contains Al2O3, Mn2+, P, and Si as impurities, which are not intentionally added to CaSO4. As the results of this study, the different impurity states may influence the radiation sensitivity of the materials. It is suggested that the deliberate addition of P and Si elements, Al2O3 and Mn2+ could control the RPL properties.

Automated summary

Recent research has found that CaSO4 exhibits remarkable radiophotoluminescence (RPL) properties without intentional addition of impurities. ESR measurements were conducted to identify the defect species responsible for RPL and determine the luminescence's origin. The results showed the presence of various impurities, including Al2O3, Mn2+, P, and Si, in CaSO4, which may affect the radiation sensitivity. Hence, deliberate addition of specific elements is suggested to control the RPL properties.