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

A highly sensitive and tissue equivalent LiF:Mg,Cu,P thermoluminescent (TL) phosphor in powder form has been developed. The TL sensitivity of this pho sphor is about 1.5 times that of Harshaw-Bicron LiF:Mg,Cu,P (TLD100-H) by p eak 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 se nsitivity. Defect centres formed in the LiF:Mg,Cu,P phosphor after high gamma dose wer e studied using electron spin resonance. Two centres assigned to (PO4)(2-) and an F-centre were observed at room temperature. Step annealing measureme nts indicate possible association between the (PO4)(2-) centre and the TL p eak at 120 degreesC. Phosphorus appears in the form of the (PO4)(3-) moiety in the lattice and is responsible for the high TL sensitivity.