摘要
安全壳内放射性气溶胶总β测量为壳内污染情况及一回路系统承压边界有无破坏、泄漏提供判断依据。对β射线敏感的塑料闪烁体对γ也敏感,γ本底扣除是总β测量中的难题。新型组合探测器用塑料闪烁体作为总β测量主探测元件,BGO作为γ测量从探测元件。根据两种闪烁体光衰减时间差可实现它们各自输出信号的甄别与计数,参照BGO中产生的脉冲计数扣除塑料闪烁体中γ本底。本工作推导出探测器中两种闪烁体对γ绝对探测效率的计算公式,用蒙特卡罗方法模拟,确定γ分别在BGO与塑料闪烁体中引起脉冲数的比例。结果表明,该组合探测器能使γ本底降低约1个数量级。
The level of gross β for radioactive aerosol in the containment of nuclear plants can indicate how serious the radioactive pollution is in the shell,and it can provide evidence which shows whether there is the phenomenon of leak in the boundaries of confined aquifer of the primary coolant circuit equipment.In the process of measuring,the counting of gross β is influenced by γ.In order to avoid the influence of γ,a new method was introduced and a new detector was designed using plastic scintillator as the major detecting component and BGO as the sub-component.Based on distinctive difference of light attenuation time,signal induced in them can be discriminated.γ background in plastic scintillator was subtracted according to the counting of γ in BGO.The functions of absolute detection efficiency were obtained.The simulation for Monte-Carlo method shows that the influence of γ background is decreased about one order of magnitude.
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2010年第1期105-109,共5页
Atomic Energy Science and Technology
关键词
放射性气溶胶
总β测量
组合探测器
radioactive aerosol
gross beta measuring
complex detector
