单球中子谱仪的能量响应模拟及解谱方法研究

Energy response simulation and unfolding method research of single sphere neutron spectrometer

本文阐述了单球中子谱仪的原理,介绍了基于单慢化球和19对6Li-7Li闪烁体探测器构成的单球中子谱仪的结构及解谱方法,使用蒙特卡罗中子输运程序模拟了单球中子谱仪的中子响应函数。计算结果表明,该谱仪具有较好的空间对称性,能根据谱仪中各探测器的计数对源的大致方位进行判断;模拟了单球谱仪在241Am-Be源照射下各探测器的计数,使用Unfolding with Maxed and Gravel (UMG)解谱程序在不同解谱算法以及初始谱的情况下对模拟数据进行解谱计算,在使用最大熵散发以及与源项相同的预置谱的情况下,解谱结果最为准确,验证了响应函数的准确性。

The principle and structure of the single sphere neutron spectrometer based on a spherical polyethylene moderator with 19 pairs of 6 Li and 7 Li scintillation detectors was described in this paper. Calculated neutron response functions by Monte Carlo Neutron-particle Transport Code showed that this spectrometer has good spatial symmetry, and the source location can be estimated by detector's counts. Simulated spectrometer was exposed in 241 Am-Be radiation field to obtain counts of each detector and to unfold the simulated results by using Unfolding with Maxed and Gravel (UMG) code to get the energy spectrum. Different algorithms and default spectrum were considered in unfolding process. Compared with expected spectrum, the spectrum unfolded by default spectrum of 241Am-Be standard source and maximum entropy method is the most accurate. The accuracy of response function is verified.