一种~(252)Cf裂变中子源的中子、γ射线飞行时间谱测量新方法

摘要

针对~(252)Cf快中子、γ射线的飞行时间谱测量要求,提出并建立一种基于高速数据采集卡的新型测量系统.采用1 GHz高速A/D转换单元和现场可编程门阵列高速处理单元,进行脉冲时间序列的在线检测,时间精度为1 ns.使用相关函数法,通过PC机的数据处理、互相关函数计算和数值统计等实现中子、γ射线飞行时间谱的测量.实验结果表明,该系统可以获得~(252)Cf自发裂变中子源的中子、γ射线飞行时间谱,与经典的飞行时间谱测量方法相比较,其图谱表达及数值结果有着很高的吻合度.%For the measurement of flight time spectrum for ~(252)Cf fast neutron and gamma ray, a new measuring system based on high-speed data acquisition card is put forward and constructed. The data acquisition card uses high speed A/D converting unit (1 GHz) and high speed processing unit. It can accomplish on-line time detecting of pulse sequence at 1 ns precision. The measurement of flight time spectrum is done by correlation function. Through data processing arrangement and cross correlation function calculation designed on PC, flight time spectra of ~(252)Cf Source fission neutron and gamma ray can be obtained. The results a-gree with those from the classical measuring system in a degree of 99. 9%, which consists of time-amplitude converter and multichannel analyzer.