分类： 物理学 >> 核物理学 提交时间： 2025-03-26
Wang, Prof. Xiaoli
Shi, Mr. Shucheng
Han, Mr. Chenyao
Ma, Mr. Yiming
Shi, Prof. Quanqi
Wang, Dr. Shuai
Feng, Ms. Jiao
Wang, Mr. Shuai
摘要： In recent years, there have been fewer missions to detect neutrons in the low Earth orbit (LEO), and the data obtained have been extremely limited. Studying the distribution of the neutron energy spectrum in LEO through detection can help to solve three major scientific problems: the source of particles in the inner radiation belt, information on solar accelerated particles and the proportion of neutrons from different sources in near-Earth space. The detection efficiency and accuracy of neutrons are affected by the charged particles and primary particles in the environment and the secondary neutrons produced by the spacecraft itself, which has been a hot research topic. The neutron spectrometer developed in this paper adopts two combinations of 15 silicon detectors in terms of detector type and arrangement, which are used for neutron detection by nuclear reaction method and recoil proton method, respectively, in which 27 $\upmu$m-thick $^6$LiF conversion layer is used for thermal neutron detection up to 0.4 eV and 300 $\upmu$m-thick high density polyethylene (HDPE) conversion layer is used for fast neutron detection up to 14 MeV and below. The design of the detector set can also remove the influence of primary charged particles and secondary neutrons in the environment to be detected to a certain extent, improving the accuracy of neutron detection. This paper has completed the neutron spectrometer hardware, firmware, software design, and the basic performance of the front-end readout chip SKIROC2A was tested, the readout circuit of each channel baseline ADC code is less than 17, so the channel consistency is good. The RMS noise of the channel baseline is only 7.1 mV and has good stability. The maximum number of events that can be processed per second is 75. The overall power consumption is 3 W, weight is 792 g, and volume is less than 1 dm$^{3}$. In addition, the neutron spectrometer was tested for principle and detection efficiency using various neutron sources such as $^{241}$Am-Be neutron source, 2.5 MeV neutron beam current, 14 MeV neutron beam current, etc., and the experiments were analyzed with corresponding simulations. The experimental data and the simulation results are in good agreement and meet the design expectations. The intrinsic detection efficiency of the probes used in neutron spectrometer is 1.05\% for 14 MeV fast neutrons.
分类： 物理学 >> 核物理学 提交时间： 2025-01-22
Wang, Prof. Xiaoli
Shi, Mr. Shucheng
Han, Mr. Chenyao
Ma, Mr. Yiming
Shi, Prof. Quanqi
Wang, Dr. Shuai
Feng, Ms. Jiao
Wang, Mr. Shuai
摘要： In recent years, there have been fewer missions to detect neutrons in the low Earth orbit (LEO), and the data obtained have been extremely limited. Studying the distribution of the neutron energy spectrum in LEO through detection can help to solve three major scientific problems: the source of particles in the inner radiation belt, information on solar accelerated particles and the proportion of neutrons from different sources in near-Earth space. The detection efficiency and accuracy of neutrons are affected by the charged particles and primary particles in the environment and the secondary neutrons produced by the spacecraft itself, which has been a hot research topic. The neutron spectrometer developed in this paper adopts two combinations of 15 silicon detectors in terms of detector type and arrangement, which are used for neutron detection by nuclear reaction method and recoil proton method, respectively, in which 27 $\upmu$m-thick $^6$LiF conversion layer is used for thermal neutron detection up to 0.4 eV and 300 $\upmu$m-thick high density polyethylene (HDPE) conversion layer is used for fast neutron detection up to 14 MeV and below. The design of the detector set can also remove the influence of primary charged particles and secondary neutrons in the environment to be detected to a certain extent, improving the accuracy of neutron detection. This paper has completed the neutron spectrometer hardware, firmware, software design, and the basic performance of the front-end readout chip SKIROC2A was tested, the readout circuit of each channel baseline ADC code is less than 17, so the channel consistency is good. The RMS noise of the channel baseline is only 7.1 mV and has good stability. The maximum number of events that can be processed per second is 75. The overall power consumption is 3 W, weight is 792 g, and volume is less than 1 dm$^{3}$. In addition, the neutron spectrometer was tested for principle and detection efficiency using various neutron sources such as $^{241}$Am-Be neutron source, 2.5 MeV neutron beam current, 14 MeV neutron beam current, etc., and the experiments were analyzed with corresponding simulations. The experimental data and the simulation results are in good agreement and meet the design expectations. The intrinsic detection efficiency of the probes used in neutron spectrometer is 1.05\% for 14 MeV fast neutrons.
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