含硼塑料闪烁体的中子-γ甄别

Neutron-γ Discrimination of Boron Loaded Plastic Scintillator

含硼塑料闪烁体在中子探测方面具有许多优良特性,由于^(10)B具有很高的慢中子俘获截面,氢具有很高的快、慢中子散射截面,因此能够实现对慢中子和快中子的同时探测。为有效区分中子和γ事件,用过零时间法对含硼塑料闪烁体BC454的中子-γ甄别能力进行了实验测量。三组对比实验的结果表明,脉冲上升时间谱存在三个明显的高斯分布,它们从左到右依次分别对应于γ射线、快中子和慢中子,因此BC454具有一定的中子-γ甄别能力,能够进行快、慢中子的同时测量。

Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to ^10 B. Both reactions have large cross sections, leading to high detection efficiency of incident neutrons. However, gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BCA54 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and slow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons＇ energy becomes higher.