Qing Shan, Hongkui Zhu, Zhiling Kong, Wenbao Jia, Daqian Hei, Yongsheng Ling
Department of Nuclear Science and Engineering, College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, Jiangsu, People's Republic of China; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Suzhou, 215000, Jiangsu, People's Republic of China.
Department of Nuclear Science and Engineering, College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, Jiangsu, People's Republic of China.
Appl Radiat Isot. 2019 Jul;149:60-64. doi: 10.1016/j.apradiso.2019.04.022. Epub 2019 Apr 20.
A new method is proposed to detect fast neutron flux: the neutron-induced X-ray fluorescence method. In this method, the neutrons are firstly converted to charged particles, and then the charged particles interact with the target to generate the characteristic X-ray fluorescence. Finally, the Kα X-ray emission from the target is detected for measurement of the neutron flux. On the basis of this method, the structure of the detection device is designed: it is composed mainly of a layer of a fast neutron converter and a layer of the target. The Geant4 Monte Carlo simulation toolkit is used to optimize the detection device. According to the simulation results, the detection device is manufactured so as to perform the feasibility verification experiments. In the experiments, a D-T neutron generator is used as the neutron source, and the number of neutrons is changed in two ways: by change of the working voltage of the neutron generator or by change of the measurement time. The experimental results show that there is a good linear relationship between the number of neutrons and the Kα X-ray counts when the measurement time is changed. When the working voltage of the neutron generator is changed, a He proportional counter is used as a reference detector. The results show that the trend of the Kα X-ray counts is in good agreement with the trend for the He proportional counter. It is proved that this method is feasible for fast neutron flux measurement.
中子诱发X射线荧光法。在该方法中，中子首先被转换为带电粒子，然后带电粒子与靶相互作用产生特征X射线荧光。最后，检测靶的Kα X射线发射以测量中子通量。基于该方法，设计了检测装置的结构：它主要由一层快中子转换器和一层靶组成。使用Geant4蒙特卡罗模拟工具包对检测装置进行优化。根据模拟结果制造检测装置，以进行可行性验证实验。在实验中，使用D-T中子发生器作为中子源，通过两种方式改变中子数量：改变中子发生器的工作电压或改变测量时间。实验结果表明，当改变测量时间时，中子数量与Kα X射线计数之间存在良好的线性关系。当改变中子发生器的工作电压时，使用氦正比计数器作为参考探测器。结果表明，Kα X射线计数的趋势与氦正比计数器的趋势高度一致。证明了该方法用于快中子通量测量是可行的。
