同轴高纯锗探测器探测效率的MCNP模拟与电荷收集时间的计算

摘要

HPGe detectors have a fine energy resolution,and are known as golden standards in nuclide analysis and considered as standard detective equipments in various detection areas.In the processing of HPGe detector,some parameters can be determined under Monte Carlo method.MCNP4 code is used to complete the simulation,and determined the material of entrance window and the thickness of the dead layer for coaxial HPGe detector,which based on the simulation result.Moreover,the code is used to compare influences of different materials and γ ray of different energy to the HPGe detector,then provide guidance for our future fabrication of HPGe detector.Furthermore,electric field simulation work inside the coaxial HPGe has been done,then the collection time of charges,produced from different energy deposition positions inside the coaxial HPGe,has been calculated.Changing positions of energy deposition can provide a perceptual intuition of the collection time of charges produced from different energy deposition positions inside the coaxial HPGe.%高纯锗探测器具有很好的能量分辨率,被认为是核素分析的黄金标准,在很多检测领域成为规定的标准检测设备.在高纯锗探测器的制备过程中,可以采用蒙特卡罗方法对探测器进行模拟,用于确定探测器制备过程中的参数.采用MCNP4软件对同轴高纯锗探测器探测效率进行模拟,研究了不同材质入射窗、不同能量γ射线对高纯锗探测器探测效率的影响,并根据模拟结果选择合适的入射窗材料并确定死层厚度,进而为高纯锗探测器研制提供指导.还对高纯锗探测器晶体的内部电场进行模拟,计算得到能量沉积点的电荷收集时间,通过改变能量沉积点位置,更直观地反映晶体内部不同位置的电荷收集时间.