CaSO4:Dy,Mn: A new and highly sensitive thermoluminescence phosphor for versatile dosimetry

Abstract

Abstract With the advent of newer techniques for dose reduction coupled with the development of more sensitive detectors, the radiation doses in radiological medical investigation are decreasing. Nevertheless, keeping the tenet in mind that all radiation doses could entail risk, there is a need to develop more sensitive dosimeters capable of measuring low doses. This paper gives the account of the development of a new and sensitive phosphor CaSO 4 :Dy,Mn and its characterization. The standard production procedure based on the recrystallization method was used to prepare CaSO 4 :Dy,Mn. The Thermoluminescence (TL) studies were carried out by exposing it with gamma radiation (Cs-137) from 10 µGy to 100 Gy. The theoretical studies to determine the number of peaks and kinetic parameters related to the TL glow peaks in CaSO 4 :Dy,Mn was performed using the Computerized Glow Curve Deconvolution (CGCD) method. Experiments were performed to determine optimum concentration of the dopants Dysprosium (Dy) and Mangnese (Mn) in the host CaSO 4 so that maximum sensitivity of the phosphor may be achieved. The optimum dopant concentration turned out to be 0.1 mol%. As there were two dopants Dy and Mn their relative ratio were varied in steps of 0.025 keeping the concentration of total dopant (Dy and Mn) 0.1 mol% always. The maximum TL intensity was seen in the CaSO 4 :Dy(0.025),Mn(0.075) combination. The TL sensitivity of this phosphor was found to be about 2 and 1.8 times higher than that of popular phosphor CaSO 4 :Dy and LiF:Mg,Cu,P (TLD-700H) respectively. This new phosphor CaSO 4 :Dy,Mn showed fading of 11% which is similar to that of the standard phosphor CaSO 4 :Dy. The paper concludes that the new, highly sensitive TL phosphor CaSO 4 :Dy,Mn has shown higher sensitivity and hence the potential to replace commonly used CaSO 4 :Dy.