中国散裂中子源多功能反射谱仪屏蔽设计  

Shielding design of the multi-purpose reflectometer of China spallation neutron source

作　　者：沈飞[1,2,3] 梁泰然[2,3,4] 殷雯[2] 于全芝[2] 左太森[3] 姚泽恩[1] 朱涛[2] 梁天骄[2] 

机构地区：[1]兰州大学核科学与技术学院,兰州730000 [2]中国科学院物理研究所,北京100190 [3]中国科学院高能物理研究所,北京100049 [4]南开大学物理系,天津300071

出　　处：《物理学报》2014年第15期68-76,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:91026009;11174358;11075203)资助的课题~~

摘　　要：本文介绍了利用蒙特卡罗粒子输运程序MCNPX2.5.0进行中国散裂中子源多功能反射谱仪屏蔽设计的屏蔽需求、辐射源项、计算方法和设计结果等内容.在计算中考虑慢化器泄漏源项、中子导管损失源项等不同辐射源项,使用分步计算和源项角度偏移、源项能量偏移、几何分裂等多种减方差方法,在保证计算结果精度的同时提高计算速度.在谱仪束线传输段、第二中子开关、散射室等的屏蔽计算中,通过比较了不同条件下的所需屏蔽确定最终屏蔽设计,确保谱仪屏蔽外人员可到达区域的剂量低于安全限值2.5μSv/h.The shielding design employing the Monte Carlo simulation code of MCNPX 2.5.0 for multi-purpose reflectometer of China spallation neutron source （CSNS） is introduced, including the shielding needs, radiation source terms, calculating methods and simulation results, etc. Various radiation source terms such as the moderator leakage source term, and the neutron guide loss source term etc. are taken into account in the simulation, and step-by-step calculation method and variance reduction methods such as source angular biasing, source energy biasing, and geometry splitting, are adopted to improve the computing speed while the precision of the results is guaranteed. In the shielding design of instrument transport beamline, second shutter, and scattering room etc., the final shielding parameters are determined by comparing the shielding need under different operating conditions, to ensure the dose rate below the 2.5 μSv/h limitation in accessible locations outside the shielding.

关 键 词：屏蔽设计 MCNPX 中国散裂中子源 多功能反射谱仪 

分 类 号：O571.5[理学—粒子物理与原子核物理]