Thermoluminescence of SrSO₄:Dy and BaSO₄:Dy (dosimetric properties)

Abstract

The thermoluminescence of SrSO4 and BaSO4 doped with dysprosium and thulium was studied. The phosphors were crystallized from H2SO4 solution by evaporation. SrSO4:Dy and SrSO4:Tm exhibit the same glow curve, both having a major glow peak at 140 degrees C. BaSO4:Dy and BaSO4:Tm also exhibit identical glow peaks at 130 degrees C which are similar to the SrSO4 peaks except for the small shift in temperature. The sensitivities of SrSO4:Dy and BaSO4:Dy relative to CaSO4:Dy are 90 and 27%, respectively, for 60Co irradiation. The following dosimetric properties of these phosphors were also measured: fading, linearity with dose and response versus photon energy. SrSO4:Dy appears most suitable for dosimetry; particularly as a quality indicator for personnel dosimetry. Its behaviour from 100 mR to 1R is, however, somewhat nonlinear.