单粒子效应辐照实验50~500 MeV准单能中子源模拟研究

Simulation of 50-500 MeV Quasi-monoenergetic Neutron Source for Single Event Effect Irradiation Experiment

中子引发单粒子效应会影响航空飞行器和地面核设施用电子器件的可靠性。准单能中子是研究中子单粒子效应规律和机理的重要中子源,通过开展辐照实验获取中子单粒子效应截面的能量依赖曲线,能预估器件在不同中子辐射环境中的单粒子错误率。基于核反应理论,研究了50~500 MeV质子与锂相互作用的中子产额及中子单能峰产额,并基于SRIM程序计算了质子在1~3 MeV能损时Li靶厚度随质子能量的变化趋势。选取质子能损为2 MeV时的Li靶厚度,采用蒙特卡罗方法,模拟计算了50~500 MeV质子与Li靶核反应的次级中子产额和不同出射方向的中子能谱。研究结果表明,0°出射方向中子具有最好的单色性,且质子流强为1μA,靶厚在质子能损为2 MeV时,准单能中子注量率可达104~105 cm^(-2)·s^(-1)(距靶5 m),单能峰占比约为50%,可满足中子单粒子效应研究需求。

The neutron-induced single event effect affects the reliability of electronic devices used in aircraft and ground nuclear facilities.With the progress of semiconductor technology,device feature sizes become smaller and more integrated,radiation sensitivity increases and neutron single event effects become more of an emphasis.To evaluate the performance of electronic devices against neutron single event effects,ground-based neutron irradiation experiments are the most commonly used method in China and abroad.The quasi-monoenergetic neutron is an important neutron source for studying the law and mechanism of the neutron single event effects.Meanwhile,through irradiation experiments with multi-energy neutron beam,the energy dependence curve of the neutron single event effect cross section can be obtained,which can be used to predict the error rate of electronic devices exposed to various neutron radiation environments.Systematic experimental studies of the energy dependence of the neutron single event effect cross section have not been carried out in China,mainly due to the fact that there are few neutron sources suitable for conducting neutron single event effect experiments in China,especially the long-term lack of quasi-monoenergetic neutron sources above 20 MeV.In recent years,with the gradual completion and commissioning of several medium-and high-energy proton accelerators in China,quasi-monoenergetic neutron experimental research has become increasingly available.Theoretical simulation studies prior to the implementation of experimental studies.Based on the nuclear reaction theory,the secondary neutron yield and the neutron single energy peak yield were studied with 50-500 MeV proton and lithium bombardment.The trend of lithium target thickness was calculated by SRIM software with 1-3 MeV proton energy loss in lithium target.The thickness of lithium target with proton energy loss of 2 MeV,secondary neutron yield and neutron energy spectrum in different emission directions were simulated by Monte Carlo method for 50-500 MeV proton.The simulation results show that quasi-monoenergetic neutrons in 0°direction have the best monochromaticity,the neutron fluence rate can reach 104-105 cm^(-2)·s^(-1) and the proportion of single energy peak is about 50%,for the position of 5 m from the Li target,when the proton intensity is 1μA and the target thickness is 2 MeV proton energy loss,which can meet the research requirements of neutron single event effect.In conclusion,this work provides theoretical guidance for the design of quasi-monoenergetic neutron targets,beamlines and experimental terminals for neutron single event effect experiments,as well as for the implementation of neutron single event effect irradiation experiments.