^(115)In中子非弹性散射截面的实验测量及蒙特卡罗修正

Experimental measurement and Monte Carlo correction of neutron inelastic scattering cross section of ^(115)In

^(115)In是一种重要的活化材料,准确测量它的中子非弹性散射截面数据对中子注量监测具有重要意义。在四川大学原子核科学技术研究所2.5 MV静电质子加速器上,利用核反应D(d,n)~3He产生的单能中子,以^(197)Au作为标准,采用活化法测量了2.95 Me V、3.94 Me V、5.24 Me V能点的^(115)In中子非弹性散射截面。用Monte Carlo程序MCNPX(Monte Carlo N-Particle eXtended)对靶头材料、冷却水层和样品的包层材料等引起的多次散射效应及注量率衰减效应等进行了修正计算,得到最终结果与Loevestam的计算值符合较好,并且实验中可通过减小靶管、靶底衬、水层及样品的包层材料等厚度来减小多次散射效应和自屏蔽效应的影响。

Background： As a kind of important activating material, accurate measurement of 115In neutron inelastic scattering cross section data of neutron flux monitoring is of great significance. Purpose： The purpose is to measure 115In neutron inelastic scattering cross section, and compare the results with the existing data. Methods： The cross section at 2.95 MeV, 3.94 MeV and 5.24 MeV was measured using the activation technique at a 2.5 MeV electrostatic accelerator of Sichuan University, and the reaction of D（d,n）3He was used for neutron sources. The deflections which were caused by multiple scattering and self-shielding of the experiment were corrected with MCNPX. Results： 115In neutron inelastic scattering cross section data at three energy values were obtained after Monte Carlo correction and the results fit well with the calculated values of Loevestam. Conclusion： The effect of multiple scattering effects and self-shielding effect can be reduced by reducing the thickness of the target tube, bottom lining, water layer and cladding material of the sample.