脉冲高度权重技术测量~(197)Au中子俘获截面

The pulse height weighting technique is a data processing method for measuring neutron capture cross-sections using a C₆D₆ detector. At the Back-n target station of the China Spallation Neutron Source (CSNS), the reliability of this method was verified by measuring the neutron capture cross-section of a gold target (¹⁹⁷Au). Firstly, the Geant4 Monte Carlo program was used to simulate and give basic items such as the detector efficiency and the pulse height weighting function under different target conditions, making the weighted detector efficiency proportional to the γ energy. Then, the neutron capture cross-section of ¹⁹⁷Au was measured experimentally. The results show that the measured neutron capture cross-section data are in agreement with the ENDF/B - VIII.0 evaluated data. At the same time, it was found that with the difference in the experimental target size and the increase in the proton beam power, the subtraction error of the experimental background will become larger and larger.

脉冲高度权重技术是利用C_6D_6探测器测量中子俘获截面的一种数据处理方法。在中国散裂中子源(China Spallation Neutron Source,CSNS)的反角白光中子源(Back-n)靶站上,通过测量金靶(~(197)Au)的中子俘获截面,验证了该方法的可靠性。首先利用Geant4蒙特卡罗程序模拟给出了不同靶条件下的探测器效率,脉冲高度权重函数等基本项,使得加权后的探测器效率与γ能量成正比。然后通过实验测量了~(197)Au中子俘获截面。结果表明:测量获得的中子俘获截面数据和ENDF/B-VIII.0评价数据相符合,同时发现随着实验靶尺寸的不同和质子束功率的增加,会使得实验本底的扣除误差越来越大。