Measurement of 169Tm(n,2n)168Tm reaction cross sections from 12 to 19.8 MeV

The cross sections of the ¹⁶⁹Tm(n,2n)¹⁶⁸Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique,relative to the ⁹³Nb(n,2n)^92mNb reaction.Thulium(Tm) samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the ³H(d,n)⁴He reaction at the 5SDH-2 1.7-MV Tandem accelerator in China.Theoretical model calculations were performed.The present data we...     

铝材料高能反射中子测量与计算

用~6~种阈探测器测得有无铝反射体时的绝对活化反应率, 获得了铝材料的高能中子反射率, 其值基本在1—1.14之间, 变化趋势比较一致. 结果表明: 高能反射中子场在小角度测量点比较弱, 而在大角度测量点, 尤其在120°点比较强. 高能中子反射率随阈能的增大而变小. 中子反射率的实验不确定度为3.4%—4.2%. 模拟计算结果与实验结果在大多数点基本相符.     

D—D中子在聚乙烯球壳内的反应率测量

开展D-D聚变中子与聚乙烯球壳作用的中子学积分实验，用于检验计算方法和相关核数据。实验装置由D—D中子源与聚乙烯球壳组成，中子源在聚乙烯球壳外，距球壳外表面35mm。聚乙烯球壳由两个半球壳组成，外径φ386mm，厚度100mm。聚乙烯球壳中心与靶心的轴线水平。     

探测系统能量分辨在中子能谱数值模拟中的应用

针对中子能谱实验的数值模拟研究中涉及到的探测系统能量分辨问题,基于系统探测伽玛和中子的对应关系以及对伽玛射线的能量分辨率,介绍了一种简便实用的数值模拟方案,利用探测系统对中子、伽玛的光响应对应关系以及其对伽玛的能量分辨率,得到系统对中子的能量分辨率,再进一步把它应用到中子能谱的数值模拟中,并对数值计算结果与相关实验数据进行比较分析。结果表明,该方法可以很好地应用于中子能谱的数值模拟研究。     

Energy calibration of a BC501A liquid scintillator using a γ-γ coincidence technique

An accurate energy calibration of a BC501A liquid scintillator by means of Compton scattering of γ-rays is described.The energy resolution and the position of the Compton edge have been precisely determined using a γ-γ coincidence technique and fitting the coincidence spectrum with a Gaussian function superimposed on a quadratic polynomial for the background.The position of the Compton edge relative to the position of the maximum and the half height of the distribution in dependence on the relevant energy resolution is discussed in detail.The results indicate that the maximum energy of the recoil Compton electron does not occur at the half height distribution but at 0.90±0.05 of the maximum height in the energy range considered.The energy resolution varies from 15.6% to 8.02% for electrons in the energy region from 0.5 MeV to 3 MeV.