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Radiation Protection Dosimetry 33:31-33 (1990)
© 1990 Oxford University Press
Role of Dy in the Thermoluminescence of CaSO4:Dy
Building on recent models of the thermoluminescence (TL) process in CaSO4:Dy, work is undertaken to delineate more specifically the role of the Dy impurity in the TL process. Thermally stimulated currents observations show that the recombination mechanism for peak 3 is bimolecular while that for peak 1 is monomolecular. TL results clearly show that the absence of Dy removes the dosimetric peak 3 near 220 oC in this material. Apparently, only Dy impurity develops the appropriate SO4--VCa centres needed for observation of these peaks. The peak-3-related centres are shown to be quite different in behaviour from that of the structurally similar peak-1 - related SO4--VCa centres. These results emphasise the importance of Dy impurities in stabilising the TL process needed to observe the dosimetric peak in this system.