水下γ谱测量中水体距离与探测效率关系研究

Study on the Relationship Between Water-to-Detection Crystal Distance and Detection Efficiency in Underwater γ Spectrum Measurement

水下γ谱仪壳体外形尺寸设计需要确定水体至探测晶体距离与探测效率的量化关系。本研究根据水下γ谱测量条件,建立溴化镧探测晶体及空心水球模型,通过数学方法,计算到达探测器晶体的特征γ射线计数率,并通过MC抽样计算方法,计算γ射线全能峰计数率。结果显示探测晶体至水体距离发生变化时,探测晶体对水中发射的特定γ射线全能峰的探测效率为恒量。该结论为水下γ谱仪壳体结构设计提供依据。

The quantitative relationship between the water to detection crystal distance and the detector efficiency must be determined in the design of the shell dimension of the underwater gamma spectrometer.In this study,a 3-inch LaBr3 crystal and hollow water sphere model was established based on the underwater γ spectrum measurement conditions.The γ-ray counting rate that reached the surface of the detector crystal and γ ray full-energy peak counting rate were calculated respectively through mathematical calculation and Monte Carlo sampling calculation.The results show that the detection efficiency of the specificγray full energy peak emitted from the water is constant while the distance between the detection crystal and the water is changing.The conclusion provides a basis for the design of the shell structure of the underwater gamma spectrometer.