252Cf裂变γ射线伴随飞行时间法刻度液体闪烁体中子探测效率

宏观检验实验是检验核数据正确性的重要实验方法之一。液体闪烁体中子探测器是中子核数据宏观检验实验中快中子能谱测量的主要探测器，其探测效率曲线的准确性关系到实验结果的精度。本文采用²⁵²Cf中子源的伴随γ射线和飞行时间法测得了液体闪烁体对2.0～10.0 MeV中子的相对探测效率曲线，同时利用飞行时间法和400 kV脉冲中子发生器的d-D反应中子源测得了2.9 MeV单能中子的绝对探测效率。将相对探测效率曲线归一到单能点的绝对效率，得到探测器在这一能区的绝对探测效率曲线。使用蒙特卡罗程序NEFF模拟相同参数的液体闪烁体探测器对10.0 MeV以下中子的探测效率曲线。最后将实验结果与模拟结果对比，结果表明实验得到的探测效率曲线合理、准确。

Calibration of Neutron Detection Efficiency for Liquid Scintillator with 252Cf Fission Gamma Ray and Time-of-Flight Method

The benchmark experiment is one of the important experiment methods for verifying the nuclear data. Liquid scintillator detector is the main detector used in the neutron nuclear data benchmark experiments, and the accuracy of the experiment results is affected by the precision of the detection efficiency of the detector directly. Using time-of-flight method and a ²⁵²Cf neutron source, the neutron relative detection efficiency curve of the liquid scintillator was measured in 2.0-10.0 MeV energy region. And the absolute detection efficiency of mono-energetic neutrons was also measured at 2.9 MeV with the time-of-flight method and the d-D reaction neutron source. After normalizing the relative detection efficiency curve to the absolute detection efficiency at 2.9 MeV, the absolute detection efficiency curve in this energy region was obtained. The calibrated detection efficiency of the liquid scintillator was also compared with the calculation result of the Monte-Carlo code NEFF, and good agreement was obtained.