On the relationship between dose-, energy- and LET-response of thermoluminescent detectors
On the relationship between dose-, energy- and LET-response of thermoluminescent detectors
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DOI：
10.1093/rpd/nci611
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发表时间：
2006-09-01
影响因子：
1
通讯作者：
Waligorski, M. P. R.
中科院分区：
文献类型：
--
作者：
Olko, P.;Bilski, P.;Waligorski, M. P. R.
热释光（TL）探测器的伽马射线剂量高到足以观察到信号饱和后的响应测量提供输入到微剂量模型，该模型将该伽马射线响应与低剂量光子（伽马射线和低能X射线）和高LET照射后的能量响应相关联。为了测量它们的γ射线响应达到饱和，用Co-60 γ射线在1-5000戈伊范围内照射LiF：Mg、Ti（MTS-7和MTT）、LiF：Mg、Cu、P（MCP-7）、CaSO 4：Dy（KCD）和Al 2 O 3：C探测器。还测量了CaSO 4：Dy和Al 2 O 3：C在β射线和α粒子剂量后的X射线光子能量响应和TL效率（相对于γ射线）。微剂量和轨道结构建模，然后应用到实验数据。以类似于LiF：Mg，Cu，P的方式，与截面计算相比，在α-Al_2 O_3：C对< 100 keV的X射线的响应下实验观察到的，被解释为由该探测器的响应的饱和引起的微剂量效应，而没有预先的超线性（沿轨道沿着的陷阱的饱和）。CaSO_4：Dy的增强的X射线光子能量响应与高γ射线剂量后在该材料中观察到的超线性有关，类似于LiF：Mg，Ti中的超线性。所讨论的模型方法支持TL探测器中剂量，能量和电离密度响应的一般规则：如果它们的伽马射线响应在饱和之前是次线性的，则测得的光子能量响应较低，如果它是超线性的，则可能高于仅从相互作用截面的计算中预期的。由于类似的规则已被发现适用于其他固态探测器系统，微剂量测定可以提供一个有价值的贡献，固态剂量测定，甚至在不同的TL探测器的物理现象的机械解释之前。
Measurements of the response of thermoluminescent (TL) detectors after gamma ray doses high enough to observe signal saturation provide input to microdosimetric models which relate this gamma-ray response with the energy response after low doses of photons (gamma rays and low-energy X rays) and after high-LET irradiation. To measure their gamma ray response up to saturation, LiF:Mg,Ti (MTS-7 and MTT), LiF:Mg,Cu,P (MCP-7), CaSO4:Dy (KCD) and Al2O3:C detectors were irradiated with Co-60 gamma rays over the range 1-5000 Gy. The X-ray photon energy response and TL efficiency (relative to gamma rays) after doses of beta rays and alpha particles, were also measured, for CaSO4:Dy and for Al2O3:C. Microdosimetric and track structure modelling was then applied to the experimental data. In a manner similar to LiF:Mg,Cu,P, the experimentally observed under response of alpha-Al2O3:C to X rays < 100 keV, compared with cross-section calculations, is explained as a microdosimetric effect caused by the saturation of response of this detector without prior supralinearity (saturation of traps along the tracks). The enhanced X-ray photon energy response of CaSO4:Dy is related to the supralinearity observed in this material after high gamma ray doses, similarly to that in LiF:Mg,Ti. The discussed model approaches support the general rule relating dose-, energy- and ionisation density-responses in TL detectors: if their gamma ray response is sublinear prior to saturation, the measured photon energy response is lower, and if it is supralinear, it may be higher than that expected from the calculation of the interaction cross sections alone. Since similar rules have been found to apply to other solid-state detector systems, microdosimetry may offer a valuable contribution to solid-state dosimetry even prior to mechanistic explanations of physical phenomena in different TL detectors.