Preparation, thermoluminescent and electron spin resonance characteristics of LiF:Mg,Cu,P phosphor

Abstract

A highly sensitive and tissue equivalent LiF:Mg,Cu,P thermoluminescent (TL) phosphor in powder form has been developed. The TL sensitivity of this phosphor is about 1.5 times that of Harshaw-Bicron LiF:Mg,Cu,P (TLD100-H) by peak height measurements. Its dose against TL response is linear up to 10 Gy. The annealing temperature was found to affect the glow curve shape and sensitivity. Defect centres formed in the LiF:Mg,Cu,P phosphor after high gamma dose were studied using electron spin resonance. Two centres assigned to (PO4)(2-) and an F-centre were observed at room temperature. Step annealing measurements indicate possible association between the (PO4)(2-) centre and the TL peak at 120 degreesC. Phosphorus appears in the form of the (PO4)(3-) moiety in the lattice and is responsible for the high TL sensitivity.