Microdosimetry, track structure and the response of thermoluminescence detectors
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- 作者：Pawel Olko
- 刊名：Radiation Measurements
- 出版年：2006
- 出版时间：1 December 2006
- 年：2006
- 卷：41
- 期：Supplement 1
- 页码：S57-S70
- 全文大小：558 K
文摘
Several properties of the response of thermoluminescence detectors after doses of ionising radiation can be explained by analysing the structure of charged particle tracks. Information on the topology of interaction points around the path of a charged particle can be represented through the radial distribution of average dose around the particle's path (Track Structure) or through quantities such as lineal energy, y, or specific energy, z, applied in Microdosimetry. A principal assumption in all microdosimetric and track structure models is that, on a per average dose basis, the local efficiency of the TL processes taking place in any small volume located in the non-uniformly distributed dose distribution around the particle's path is similar to that after irradiation with a uniformly distributed dose of γ-rays. Since saturation of γ-ray response at high doses then translates to saturation of this response over regions of high dose close to the path of the heavy charged particle, track structure theory and microdosimetric models are able to explain the decrease of TL efficiency after irradiation by heavy charged particles, and the anomalously low photon energy response of LiF:Mg,Cu,P after doses of X-rays. The enhanced photon energy response and enhanced response after heavy charged particle irradiation of LiF:Mg,Ti are connected with the supralinearity of this detector at higher doses of gamma-rays: if this response is sublinear (prior to saturation) the measured photon energy response is lower, and if it is supralinear—it is higher than that expected from the calculation of the interaction cross sections alone. The explanation of the correlation between dose-, energy- and LET-responses of TLDs is perhaps the most important contribution of microdosimetry to solid state dosimetry.