Monte Carlo calculation of the efficiency response of a low-background well-type HPGe detector
Monte Carlo calculation of the efficiency response of a low-background well-type HPGe detector
复制标题
低本底井型 HPGe 探测器效率响应的蒙特卡罗计算
DOI：
10.1016/s0168-9002(01)00942-1
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Girard
中科院分区：
文献类型：
--
作者：
J. Laborie;G. Petit;D. Abt;M. Girard
井式HPGe探测器具有联合收割机的低本底和高探测效率的特点，非常适合于少量环境样品的分析。在Modane地下实验室安装了一个低本底井型探测器。在井的几何形状中，重合求和效应很高，并且使得利用通常的校准标准难以构建全能量峰值效率曲线，特别是在高能量范围内。使用GEANT代码，考虑到检测器和源的详细描述，效率曲线已被建模为几个灌装高度的小瓶。用一个特殊的程序，考虑到放射性核素的衰变计划，已计算出的符合求和效应时发生的测量样品含有238 U，232 Th或134 Cs的校正。计算结果与实验数据吻合较好。结果表明，在~（134）Cs的604和796 keV谱线情况下，三重符合对计数损失的影响占对符合影响的7-15%。
Well-type HPGe detectors are well suited for the analysis of small amounts of environmental samples, as they can combine both low background and high detection efficiency. A low-background well-type detector is installed in the Modane underground Laboratory. In the well geometry, coincidence-summing effects are high and make construction of the full energy peak efficiency curve difficult with the usual calibration standard, especially in the high energy range. Using the GEANT code, taking into account a detailed description of the detector and the source, efficiency curves have been modelled for several filling heights of the vial. With a special routine, taking into account the decay schemes of the radionuclides, corrections have been computed for coincidence-summing effects that occur when measuring samples containing238U,232Th or134Cs. The results are found to be in good agreement with experimental data. It is shown that triple coincidences effect on counting losses accounts for 7–15% of pair coincidences effect in the case of the 604 and 796keV lines of134Cs.