薄壁快脉冲^252Cf裂变电离室的研制及性能测试

Design and Test of a Thin Wall and Fast Pulse ^(252)Cf Ionization Chamber

介绍了用于中子探测器效率刻度的薄壁快脉冲252Cf裂变电离室。在用飞行时间法测量中子能谱时,该裂变电离室能够给出252Cf裂变中子发射时刻信号,输出脉冲上升时间约为5.5 ns,电离室由厚度为0.15 mm的不锈钢构成。测试结果表明,对裂变碎片的探测效率为99.2%,α粒子脉冲幅度和碎片脉冲幅度可清晰分开。

A thin wall, fast pulse ^252 Cf ionization chamber, which was designed for calibrating efficiency of neutron detectors, was described. The ionization chamber can be used as the start detector in time-of-flight measurements of the ^252Cf fission neutron spectrum. The chamber is composed of 0.15 mm thick stainless steel, the rise time of pulse signals is about 5.5 ns. As the test result shows, the detection efficiency of fission fragments is 99.2%, and pulse signals caused by fissions are distinguished clearly from those caused by α decays.