铝材料高能反射中子测量与计算

Measurement and Calculation of High-Energy Reflected Neutrons from Aluminum

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．

Using six different high-threshold neutron-activation detectors, the activation reaction rates are obtained with and without the A1 reflector. Measured reflectivities of high-energy neutrons from A1 reflector are also obtained as the ratio of measured data and range from 1 to 1.14. For different activation detectors, the shape of the reflectivities as function of measurement angles is rather similar. The intensity of the reflected high-energy neutron field is high at large angles and smaller towards smaller angles. With increasing thresholds of the activation detectors, the reflectivities decrease. Evaluated total uncertainties of reflectivities are 3.4%-4.2%. Calculated results of reflectivities agree with the experimental results at the majority of the measuring points.