基于镅铍中子源的核素分析探测系统优化

Optimization of a Nuclide Detection System Based on Am-Be Source

基于镅铍中子源及瞬发伽马分析技术,构建了核素分析探测系统,对系统进行了优化设计;实验测量了屏蔽设计对瞬发伽马能谱的影响,评估了LaBr_3:Ce探测系统的探测下限。结果表明,设计的慢化屏蔽结构有效提高了待测样品中的热中子密度,同时降低了伽马本底;系统能够实现核素的定性分析测量,对C、H、O、N等常见核素的探测下限约在千克量级。

A nuclide detection system using prompt gamma activation analysis techniques was established based on an Am-Be neutron source. The shielding configuration of the system was designed and optimized, and its effect on the prompt gamma energy spectra was analyzed experimentally. The detection threshold of the system was evaluated according to the back- ground interference, neutron spectrum, and detection efficiency. The results show that the shielding configuration of the system can greatly enlarge the flux of the thermal neutrons in the sample and effectively decrease the background gamma-rays, and the detection thresholds for C, H, O, and N are at kilogram level.