空间中子对在轨运行的航天器及航天员的辐射安全会产生重要影响，对其开展测量是关乎航天安全的重要工作。由于空间射线具备高能、种类多等特点，而在轨运行设备又在发射质量、尺寸和运行功率等方面受限，因此，对适用于空间辐射测量探测器的研制是较为困难的。本论文对基于Cs2LiYCl6:Ce3+(CLYC)闪烁体的空间中子测量技术开展了研究，为国家重大专项项目“载人空间站工程空间应用系统空间环境要素监测”（科总字[2017]7号）提供了技术实现方案。 由高能宇宙射线反应生成的空间中子具有能量范围宽的特点，因此要求探测器具备对 [热中子,100] MeV 能区的快中子探测能力。目前，对CLYC探测器在20MeV 以下能区已开展了较为充分的实验研究，但对20MeV以上能区尚未进行深入探索。高能中子在与探测器发生作用时，核反应和电离发光过程都非常复杂，无法通过理论分析或模拟计算来得到关于中子能谱的可信结果，必须开展实验研究。高能单能中子束流的获取方法，以及高能中子能谱的非单能响应特性给解谱矩阵的获取与解谱算法提出的挑战，均是本论文要解决的难题。 在论文工作中，研制了基于 SiPM 读出的 CLYC 探测器，设计了双通路读出电子学以使探测器可覆[0.1,100] MeV的中子能区。结合中国散裂中子源Back-n束线提供的 [0.1,100]MeV白光中子，设计实验并尽可能减少质子双束团结构对中子飞行谱测量的影响，获得了[0.1,100]MeV 能区中子的探测器响应矩阵；发展了基于Tikhonov正则化方法的解谱算法，实现了 [0.1, 100] MeV 宽能区中子能谱的重建。在此基础上，通过设置反符合探测器和利用脉冲形状甄别技术分别判弃了?子和𝛾射线本底，成功地对不同海拔高度的环境中子能谱进行了测量，得到了海拔高度从 575 米到 8000 米的中子能谱，结果与理论分析值及其他实验结果符合得较好。此外，空间站实验舱的中子测量范围要求为热中子-100MeV，而热中子-0.1MeV 范围中子与 6Li 的反应能（ Q=+4.78MeV）远大于入射中子能量，很难进一步区分中子能量。因此，热中子-0.1MeV 中子通过反应的特征峰来确定， [0.1, 100] MeV 中子通过解谱进行确定。 论文工作所研制的探测器及实现的测量方法，已经通过中国科学院国家空间科学中心的初样鉴定，为接下来的正样鉴定和升空工作奠定了良好基础。
Neutrons will have important effects on the radiation safety of orbiting spacecraft and astronauts, and their measurement is an important task related to space safety. Because cosmic rays have the characteristics of high energy and various types, and the on-orbit operating equipment is limited by the mass, size and operating power, it is difficult to develop detectors suitable for space radiation measurement. This paper studies the detection of space neutrons based on Cs2LiYCl6:Ce3+ (CLYC) scintillator, which provides a technical implementation plan to meet the ”Monitoring of Space Environment Elements of Manned Space Station Engineering Space Application System” ([2017] No.7). Space neutrons generated by high-energy cosmic ray reactions have a wide energy range, so the detectors are required to have the ability to detect neutrons in the [thermal neutron,100] MeV energy region. Experimental research has been carried out on the CLYC detector in the energy region below 20 MeV, but the energy region above 20 MeV has not been deeply explored. The nuclear reaction and ionization luminescence process are very complicated when the high-energy neutron interacts with the detector, and it is impossible to obtain reliable results about the neutron energy spectrum by theoretical analysis or simulation calculation. So experimental research must be carried out. The acquisition method of the high-energy monoenergetic neutron beam, and the challenges that the non-monoenergy response characteristics of the high-energy neutron spectrum pose to the acquisition of the unfolded matrix and the unfolded algorithm are all difficult problems to be solved in this paper. In our work, a CLYC detector based on SiPM readout is developed, and the dualchannel readout electronics are designed so that the detector can cover the neutron energy region of [0.1,100] MeV. Using the [0.1,100] MeV white neutrons provided by the China Spallation Neutron Source Back-n beamline, an experiment was designed and the effect of the proton double-bunch structure on the neutron flight spectrum measurement was unfolded? the detector response matrix of neutrons in the [0.1, 100] MeV energy region was obtained? a unfolded algorithm based on the Tikhonov regularization method was developed? the reconstruction of the neutron energy spectrum in the [0.1, 100] MeV wide energy region was realized. by setting up anti-coincidence detectors and using pulse shape discrimination techniques, the backgrounds of the ? and 𝛾 rays were discarded, and the neutron energy spectra at different altitudes were successfully measured.obtained the neutron energy spectrum from 575 meters to 8000 meters above sea level. The results are in good agreement with the theoretical analysis values and other experimental results. Inaddition, the neutron measurement range of the experimental cabin of the space station is required to be thermal neutron-100MeV， Because the reaction energy (Q=+4.78MeV) of neutron and 6Li with the thermal neutron-0.1MeV range is much larger than the incident neutron energy, it’s difficult to further distinguish neutron energies. Therefore, thermal neutrons-0.1MeV neutrons are identified by the characteristic peaks of the reaction, and [0.1,100]MeV neutrons are identified by unfolded algorithm. The detector developed in this thesis work and the measurement method realized have passed the initial sample identification of the National Space Science Center of the Chinese Academy of Sciences, which has laid a good foundation for the subsequent identification and lift-off of the original sample.
