Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501 A liquid scintillation detecto...Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501 A liquid scintillation detector is described. The recoil proton spectrum of 241Am-Be neutrons was obtained experimentally. With the NRESP7 code, the response matrix of detector was simulated.Combining the recoil proton spectrum and response matrix, the unfolding of neutron spectra was performed by GRAVEL iterative algorithm. A MatLab program based on the GRAVEL method was developed. The continuous neutron spectrum of 241Am-Be source and monoenergetic neutron spectrum of D-T source have been unfolded successfully and are in good agreement with their standard reference spectra. The unfolded 241Am-Be spectrum are more accurate than the spectra unfolded by artificial neural networks in recent years.展开更多
With a Geant4 software package based on the Monte Carlo method, a multi-cell 4π detection system is designed, which consists of 40 Gadolinium-loaded liquid scintillation detectors. These detectors, associated with a ...With a Geant4 software package based on the Monte Carlo method, a multi-cell 4π detection system is designed, which consists of 40 Gadolinium-loaded liquid scintillation detectors. These detectors, associated with a fission chamber in its geometrical center, constitute a platform. This platform is mainly used for the measurement of a fissionable nucleus(n, 2n) reaction cross section. In order to properly determine the experimental set-up, we carry out a systematic numerical simulation using our model which is established by the Geant4 software package. This work provides rich and valuable reference data for experiments on the fissionable nucleus(n, 2n) cross section measurement in the future.展开更多
文摘Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501 A liquid scintillation detector is described. The recoil proton spectrum of 241Am-Be neutrons was obtained experimentally. With the NRESP7 code, the response matrix of detector was simulated.Combining the recoil proton spectrum and response matrix, the unfolding of neutron spectra was performed by GRAVEL iterative algorithm. A MatLab program based on the GRAVEL method was developed. The continuous neutron spectrum of 241Am-Be source and monoenergetic neutron spectrum of D-T source have been unfolded successfully and are in good agreement with their standard reference spectra. The unfolded 241Am-Be spectrum are more accurate than the spectra unfolded by artificial neural networks in recent years.
基金Supported by National Natural Science Foundation of China(No.11375063)the Fundamental Research Funds for the Central Universities(No.13QN59)
文摘With a Geant4 software package based on the Monte Carlo method, a multi-cell 4π detection system is designed, which consists of 40 Gadolinium-loaded liquid scintillation detectors. These detectors, associated with a fission chamber in its geometrical center, constitute a platform. This platform is mainly used for the measurement of a fissionable nucleus(n, 2n) reaction cross section. In order to properly determine the experimental set-up, we carry out a systematic numerical simulation using our model which is established by the Geant4 software package. This work provides rich and valuable reference data for experiments on the fissionable nucleus(n, 2n) cross section measurement in the future.
文摘本文详述了自主研发的一种新型液体闪烁体探测器。该探测器的灵敏体积由一个圆柱体和一个圆台拼接而成,因此使得最大直径为3 in的液体闪烁体可以通过圆台能够与1.5 in光电倍增管进行直接对接,无需额外光导。为了选取圆台的最佳倾斜角度,首先利用Geant4模拟软件对不同圆台倾斜角度的探测器光收集效率进行模拟,然后制作角度分别为30°、45°和60°的探测器进行最佳角度的实验验证。实验首先使用22Na和60Coγ源对探测器进行能量刻度并进行光收集效率对比,在误差范围内实验测得的光收集效率随角度的变化规律与模拟结果基本一致,即随着斜面角度的增大,光的收集效率逐渐增高,并且随着角度增大光收集效率的增加越来越快。然后使用252Cf中子源对其中子γ甄别性能进行测试,并基于电荷比较法计算出相同能量阈值下的FOM(Figure of Merit)值,计算结果表明,随着液闪探测器光收集效率的提升,其中子γ甄别性能也得到增强。
