Integral Experiment of Large Slab Polyethylene Samples With 14.8 MeV Collimated Neutron Beams

An experimental facility for measuring the secondary neutron emission spectrafrom 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.