An experimental facility for measuring the secondary neutron emission spectra from slab sample with collimated D-T neutron source based on time-of-flight (TOF) technique has been established at China Institute of Atomic Energy (CIAE). The measurement of the neutrons leakage spectra from polyethylene slab samples of different thickness at 30-and 50-was carried out firstly. The measured results were compared with the calculated ones by MCNP simulation. The angle dependent neutron energy spectra of the neutron source, influence of the target material on the neutron source, width of pulse beam and detection efficiency were considered carefully in the simulation. The experimental results agree with the calculated results within the experimental uncertainties.%本文介绍了中国原子能科学研究院建立的准直中子束积分实验装置.该装置利用T(d,n)4 He反应产生14.8 MeV脉冲中子束,经1.1m厚重水泥屏蔽墙上的准直孔道后与样品作用,用飞行时间法测量样品不同方向的泄漏中子谱.首次测量了样品厚度分别为4.5、9、18和27 cm的大块板状聚乙烯样品在30°和50°方向的泄漏中子谱；考虑靶结构、源中子能谱和角分布、脉冲束宽度及探测器效率,利用MCNP程序模拟计算了相同实验条件下的泄漏中子飞行时间谱.实验结果与模拟结果符合较好.
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