高纯锗探测器探测效率研究

The detecting efficiency of HPGe detector

利用系列标准γ射线源对高纯锗探测器的探测效率进行了各种测量,与蒙特卡罗计算程序相结合,对于高纯锗探测效率进行了分析和讨论。计算效率与测量效率在4％以内吻合。在一定探测距离条件下面源与点源的探测效率在1％以内吻合,而且面源的自吸收可以用平行束在材料中的自吸收来计算;当面源靠近探测器时,由于γ射线的倾斜入射,这种方法就不适用了,需要用蒙特卡罗方法进行自吸收较正。

Measurements of HPGe efficiency were made by several standard gamma-ray sources. Analysis was made by the way of measurement and Monte Carlo calculation program. The efficiency results of calculation agreed with the measurement in the accuracy of 4%. At sufficient distance from the detector, the efficiency of point source equaled to plate source in 1%, and the gamma-ray self-absorption of plate source can be calculated by the parallel beam geometry. However, when the plate source was close to the detector, the expression for the parallel beam geometry does not apply because of the oblique angles of the gamma rays accepted by the detector. The sample absorption can be calculated with Monte Carlo techniques.