金刚石探测器材料研制与中子探测性能研究

Material Development and Neutron Detection Performance of Diamond Detector

核技术领域快中子监测需要探测器具有耐辐照、快响应和耐高温等特点。相比于其它探测器,金刚石探测器具有体积小、抗辐照能力强、时间响应快等优点,目前国内市场上成熟的探测器产品均采用国外的探测器级金刚石材料。本文基于市售的高温高压单晶晶种,采用氧原子等离子体净化实现杂质并入的控制,获得了低杂质含量的高质量单晶金刚石。金刚石经封装后应用于中国散裂中子源进行中子监测试验,实现了对中子脉冲的能量监测。探测器的中子飞行时间谱显示出明显的脉冲分辨,由于C-12原子核与高能中子高的散射截面,在飞行时间谱上产生了对应的共振峰结构,且中子飞行时间谱显示出较高的可靠性,受探测器波动的影响较小,表明当前的金刚石探测器能够满足快中子束流监测的需求。

Fast neutron monitoring in nuclear technology requires detectors with radiation resistance,fast response and high temperature resistance.Compared with other detectors,the diamond detector has the advantages of small size,strong irradiation resistance and fast time response.At present,all the mature detector products in domestic market are made of foreign diamond materials.Based on high pressure and high temperature(HPHT)single crystal diamond seeds,high quality single crystal diamond with low impurity content was obtained by using atomic oxygen plasma purification to control the impurity incorporation.The encapsulated diamond was used in neutron monitoring test of China spallation neutron source(CSNS),and the energy monitoring of neutron pulse was realized.The neutron time-of-flight spectrum of the detector shows obvious pulse resolution.Due to the high scattering cross section between C-12 nucleus and high-energy neutron,the corresponding resonance peaks are generated on the time-of-flight spectrum.Moreover,the neutron time-of-flight spectrum shows high reliability and is less affected by detector fluctuations,indicating the diamond detector can meet the requirements of fast neutron beam monitoring.