Mehta S K, Sengupta S
Phys Med Biol. 1977 Sep;22(5):863-72. doi: 10.1088/0031-9155/22/5/005.
Thermal annealing characteristics of the glow peaks from 200 to 650 degrees c in Al2O3 thermoluminescent (TL) phosphor have been studied. All the glow peaks show exponential decay and follow first-order kinetics. The trap depths and frequency factors for the glow peaks have been determined from their isothermal decay and from their initial rise. The trap depths, E, obtained for different glow peaks (peak temperature Tm) can be approximated by the relation E(eV)=Tm (K)/325 and the corresponding frequency factor, s, varies from 10(14) to 10(16) s-1. The measured values of E, s and Tm for the glow peaks are shown to be consistent with the equation for glow peak temperature. The annealing characteristics and actual high temperature irradiations show that the 250, 475 and 635 degree c peaks can be used for elevated temperature dosimetry up to 150, 300 and 440 degrees C respectively. It is suggested that surface defects related to Si impurity in Al2O3, propagated into the lattice on high temperature treatment close to the melting point, are responsible for the TL traps. The trapped charges responsible for TL are shown to be electrons by photostimulated thermoluminescence studies under the F centre excitation in this phosphor.
研究了Al2O3热释光（TL）荧光粉中200至650摄氏度辉光峰的热退火特性。所有辉光峰均呈指数衰减并遵循一级动力学。通过等温衰减和初始上升确定了辉光峰的陷阱深度和频率因子。不同辉光峰（峰值温度Tm）获得的陷阱深度E（电子伏特）可通过E(eV)=Tm (K)/325近似，相应的频率因子s在10(14)至10(16) s-1之间变化。辉光峰的E、s和Tm测量值与辉光峰温度方程一致。退火特性和实际高温辐照表明，250、475和635摄氏度的峰分别可用于高达150、300和440摄氏度的高温剂量测定。有人认为，与Al2O3中Si杂质相关的表面缺陷在接近熔点的高温处理时扩展到晶格中，是TL陷阱的原因。通过在该荧光粉中F中心激发下的光激发热释光研究表明，负责TL的俘获电荷是电子。
