提高LiF:Mg,Cu,P热释光探测器热稳定性和降低残余信号的研究

The study of improving the stability to heat treatment and reducing the residual signal of LiF:Mg,Cu,P

通过改变杂质Mg和Cu的浓度的方法,制备了一种新的LiF:Mg,Cu,P探测器,在不退火重复使用中灵敏度稳定的前提下,降低了残余信号.在250～270℃范围内,退火10min时,发光曲线形状没有发生明显的变化,且灵敏度保持稳定.灵敏度约为GR-200A的一半,TLD-100的30多倍,退火温度和读出温度可以提高到260℃,重复使用灵敏度保持稳定;残余信号小于0.2%,约为GR-200A的1/5.保持了GR-200A的主要优点,且具有较低的残余信号和较好的热稳定性.

This new LiF：Mg,Cu,P allows temperature treatments above 240℃to reduce the residual signals on condition that its thermoluminescent response keeps stable in re-use cycles without the necessity of an initialisation procedure. The glow curve shape shows minimal differences and the sensitivity remains stable when annealed in the range from 250℃to 270℃ for 10 min. The TL sensitivity to gamma radiation is about half in that of GR-200A and 30 times higher than that of TLD-100. The residual signal is less than 0. 2% following a 260℃ readout for 12s at a heating rate of 15℃/s, which is roughly 5 times lower than that of the standard LiF.Mg,Cu,P（GR-200A）. The TL response at 260℃ is reproducible within a coefficient of variation of 2 % over ten re-use cycles without systematic decrease. The new samples remain the main advantages of GR-200A phosphor, and have lower residual signal and bet- ter stability to heat treatment.