三维方孔硅探测器的热中子探测影响研究

采用基于Monte-Carlo方法的Geant4程序对填充~6LiF中子转换材料的三维方孔硅探测器的热中子探测进行了模拟,研究了探测器结构与探测效率、能量沉积谱的关系。探究了方孔截面尺寸、孔间距、孔深度、系统最小可探测限(LLD)等参数对热中子探测效率的影响。研究结果表明,探测效率随截面尺寸或孔间距的增大先增加后减小,随孔深度的增加而增大,直到一个极限值。经优化结构参数,在LLD为300 keV的情况下,孔间距大于6μm的三维方孔硅探测器的探测效率受LLD的影响较小。理论上,三维方孔硅探测器的最佳尺寸为孔间距6μm、孔截面尺寸30μm、孔深度1 mm,其探测效率可达59.5%。

Study on Effect of Thermal Neutron Detection for Three-dimensional Square Pore Silicon Detector

The detection efficiency of thermal neutron and deposited energy spectrum for various structures of three-dimensional square pore silicon detector with 6LiF used as a neutron conversion material were simulated with Geant4 program based on Monte-Carlo method.The influence of pore parameter on detection efficiency was studied in detail.The pore size,pore space,pore depth and the lowest limit of detection (LLD) were employed to discuss the change of detection efficiency of thermal neutron.The results show that the detection efficiency increases at first and then decreases with increase of pore size or pore space,while it increases constantly to an extreme with pore depth.When the LLD is 300 keV,the detection efficiency of three-dimensional square pore silicon detector with pore space more than 6 μm is less affected by LLD.In theory,the three-dimensional square pore silicon detector with pore space of 6 μm,pore size of 30 μm and pore depth of 1 mm achieves the highest detection efficiency of 59.5 ％.