基于微通道板的中子探测器γ射线灵敏度

研制了一种基于微通道板的超快脉冲中子探测器，对其γ射线灵敏度进行了理论和实验研究。建立了探测器的γ射线灵敏度理论计算模型，利用蒙特卡罗方法模拟计算了不同能量γ射线在不同厚度聚乙烯靶中产生的出射电子能谱和出射角度分布，并结合经验公式计算了单个电子在微通道板(MCP)孔道中产生的二次电子产额，最后得到了探测器的γ射线灵敏度，结果表明当聚乙烯靶厚度大于某一值时，γ射线灵敏度基本相同。利用西北核技术研究所的标准γ射线放射源对探测器的γ射线灵敏度进行了实验标定，实验结果与理论计算结果一致。

Gamma ray sensitivity of neutron detector based on microchannel plate

A new ultrafast pulse neutron detector based on MCP is introduced. The γ-ray sensitivity of the detector was investigated through simulation and experiment. A model of theoretical simulation was set up for γ-ray sensitivity calculation. In this model, the energy spectra and emitting angle distribution of electrons which were produced by different energy's γ-ray injecting into the different thickness' polyethylene were calculated through Monte Carlo methods. Then, the yields of secondary electrons produced by the single electron injecting into microchannel of MCP were also calculated through the experiential formula. The γ-ray sensitivity of the detector was finally obtained. The results shown that the γ-ray sensitivity of the detector was almost constant when the thickness of polyethylene was above a certain value. Some experiments were performed to test the γ-ray sensitivity at the standard gamma ray sources of Northwest Institute of Nuclear Technology. The simulated results agree with the results of experiments considering the uncertainties.