用FLUKA程序模拟设计中国散裂中子源的束流垃圾桶结构

Using FLUKA code to simulate and design the beam dumps' structure of CSNS

为使用FLUKA程序模拟设计中国散裂中子源(CSNS)的束流垃圾桶结构,先利用日本原子能研究所(JAERI)使用MCNPX程序对其3 GeV质子束流垃圾桶的辐射剂量计算结果,作了FLUKA与MCNPX的对比验证。结果表明,在30%误差范围内,FLUKA模拟结果与MCNPX的结果相符,束斑大小对辐射剂量无重要影响。随后采用梯形切片划分垃圾桶区域,用FLUKA模拟了CSNS上1.6GeV的束流垃圾桶结构。结果表明,用FLUKA程序并采用梯形切片,可方便地引入区域重要性方差减小技巧和改变垃圾桶材料厚度,从而优化束流垃圾桶结构。

To use FLUKA code calculating beam dumps' structure of Chinese spallation neutron source(CSNS),FLUKA and MCNPX were compared through the results got by Japan atomic energy research institute(JAERI) utilizing MCNPX code for calculating the radiation dose of its 3 GeV proton beam dump.Calculation results indicated that FLUKA agreed well with MCNPX within 30% error range,and beam spot size impact little to radiation dose.After this test,FLUKA was used for simulating and designing the structure of 1.6 GeV beam dump of CSNS,by dividing the whole beam dump into small trapezoid sections.The result shows that using FLUKA code and trapezoid section can easily employ variance reduction technique of importance biasing and optimize the beam dump geometry.