Folkard M, Roper M J, Michael B D
Cancer Research Campaign, Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, UK.
Phys Med Biol. 1989 Jun;34(6):707-15. doi: 10.1088/0031-9155/34/6/006.
Measurements of the response of lithium fluoride TLD-100 to 1.5 keV ultrasoft x-rays, 240 keV x-rays and 137Cs gamma-rays at doses below 70 Gy are presented and the implications for the track interaction model are discussed. This model proposes that thermoluminescence is due to the combination electrons and holes formed along secondary charged particle tracks. As the dose is increased, the average distance between particle tracks is reduced and there is a greater probability of combination between neighbouring tracks; this mechanism is used to explain the supralinear response of lithium fluoride to certain radiations. Measurements using ultrasoft x-rays are interesting in this context because the energy from each photon is deposited in a small volume, therefore the probability of combination between neighbouring events should only be significant at high doses. The results, however, show that lithium fluoride exhibits a significant supralinear response to 1.5 keV x-rays after only a few tens of grays and suggests that the track interaction model alone cannot explain the phenomenon of supralinearity.
本文给出了在剂量低于70 Gy时，氟化锂TLD - 100对1.5 keV超软X射线、240 keV X射线和137Csγ射线的响应测量结果，并讨论了其对径迹相互作用模型的影响。该模型认为热释光源于沿次级带电粒子径迹形成的电子与空穴的复合。随着剂量增加，粒子径迹之间的平均距离减小，相邻径迹复合的概率增大；此机制用于解释氟化锂对某些辐射的超线性响应。在这种情况下，使用超软X射线进行测量很有意思，因为每个光子的能量沉积在一个小体积内，因此相邻事件复合的概率仅在高剂量时才显著。然而，结果表明，氟化锂在仅几十戈瑞的剂量后就对1.5 keV X射线表现出显著的超线性响应，这表明仅靠径迹相互作用模型无法解释超线性现象。
