【摘要】 载钆液闪探测器是高能物理及核物理实验中重要的粒子探测工具。通过研制得到了一台大体积的直径为30 cm等高圆柱形载钆液闪探测器,载钆液闪溶液的载钆量为0.5%wt;利用252Cf中子源进行了中子与γ分辨性能实验测试,结果表明,直径30 cm等高圆柱形载钆液闪的中子与γ分辨性能较差;利用飞行时间技术通过符合测量的方法,分别测量了中子与伽马分辨谱中的中子与γ信号的时间分布,两者峰位之间的时间差为2 ns;利用252Cf裂变电离室的裂变碎片信号作为开门信号,通过符合测量的方法,获得了直径30 cm等高圆柱形载钆液闪的中子俘获时间分布实验数据,中子俘获平均时间为11μs。对于较大体积条件下,载钆液闪的中子与γ分辨性能较差的物理现象,通过实验给出了合理解释和分析。更多还原

【Abstract】 Background:The gadolinium-loaded liquid scintillator detector is an important tool for particle detecting in the area of high energy physics and nuclear physics experiments.Purpose:In this work,a large-size φ30 cm×30 cm gadolinium-loaded liquid scintillator detector has been developed for neutron measurement.Neutron gamma discrimination and distribution of neutron capture time of gadolinium-loaded liquid scintillator were main values of detecting performance.Methods:The n-gamma discrimination of the large-size gadolinium-loaded liquid scintillator detector has been studied using a 252 Cf spontaneous fission neutron source by zero-crossing method.It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was poor.n-gamma discrimination spectra of φ30 cm×30 cm gadolinium-loaded liquid scintillator detector within 1 ms after the fission event were captured with coincidence method based on the start signal of fission fragment from 252 Cf fission chamber.Results:It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was also poor.The time distributions of neutron and gamma in the n-gamma discrimination spectra were measured by time-of-flight(TOF) technique and coincidence method.The peak time difference of neutron time distribution and gamma time distribution was 2 ns.The distribution of neutron capture time was measured for a φ30 cm×30 cm gadolinium-loaded liquid scintillator detector with coincidence method based on the start signal of fission fragment from 252 Cf fission chamber.The main signals of γ by neutron capture of φ30 cm×30 cm gadolinium-loaded liquid scintillator detector were in about 30 ms.The average time of neutron capture is 11 ms.Conclusion:The neutron capture time property of homemade gadolinium-loaded liquid scintillator meets the experimental requirements.For the most signal of neutron and gamma within the superposition,single peak was presented in the n-gamma discrimination spectra.Therefore,the n-gamma discrimination could not be realized.The phenomenon of the poor neutron-gamma discrimination property of φ30 cm×30 cm gadolinium-loaded liquid scintillator detector was explained clearly based on the experiments.更多还原