江门地下中微子实验室HPGe γ谱仪性能模拟研究

Simulation Study on the Performance of HPGe gamma Spectrometer in Jiangmen Underground Neutrino Observatory

利用Geant4模拟研究HPGe γ谱仪在江门地下700 m实验室的性能。研究表明:江门地下实验室中,HPGe γ谱仪的本底(100 - 2 700 keV)将可达到低于0.105计数/min。该研究结果将可用于江门及其他类似实验室的低本底高纯错γ谱仪的设计和性能参考。提出了能够进一步改进高纯错γ谱仪性能的方法,即在HPGe γ谱仪中增加反康普顿探测器。增加反康普顿探测器后,谱仪积分本底将可减少约为原来的1/27,对40K的检出限降低至μBq/kg。

The Geant4 simulation is used to study the performance of the HPGe γ spectrometer in the Jiangmen underground 700 m laboratory. The results show that the background of the HPGe γ spectrometer (100~2 700 keV) in Jiangmen underground laboratory can reach less than 0.105 count/min. The results of this study will be used in the design and performance reference of low background high purity gamma spectrometers in Jiangmen and other similar laboratories. A method to further improve the performance of the high-purity gamma spectrometer is proposed, which is to add an anti-Campton detector to the HPGe γ spectrometer. When the anti-Compton detector is added, the spectrometer integration background can be reduced by about 27 times, and the detection limit of is reduced to μBq/kg.