涂硼电离室中子探测效率和灵敏度

从电离室工作原理导出了平板型涂硼中子电离室探测效率及灵敏度的计算公式，并求得其热中子探测效率和灵敏度。电离室对热中子探测效率饱和值为1.35%，灵敏度饱和值为9.65×10^-14A?cm^-2?s^-1，与已有公式所得结果8.43×10^-14A?cm^-2?s^-1相近。α粒子和Li离子对探测效率的贡献相差不大，但α粒子对灵敏度的贡献占主导地位。适当的硼膜厚度、慢化快中子、选用浓缩硼均有利于提高涂硼电离室探测效率和灵敏度。

Detection Efficiency and Sensitivity of Boron-Lined Ionization Chamber for Neutron

Formulas for detection efficiency and sensitivity of plate boron-lined ionization chamber were derived from its working principle, and their values for thermal neutrons were obtained. The saturated value of the detection efficiency for thermal neutrons of ionization chamber is 1.35% and the sensitivity is 9.65×10^-14 A?cm^-2?s^-1, which approximately coincides with the result of 8.43×10^-14 A?cm^-2?s^-1 given by a known formula. Contribution of α particles to the detection efficiency shows small difference with Li ions while that to the sensitivity is predominating. A suitable thickness of boron film, slowing fast neutron and using enriched boron can improve both detection efficiency and sensitivity of boron-lined ionization chamber.