3.24 Measurements of photo-neutron energy spectra from thick targets produced by irradiation of 2.0 GeV electron beam

摘要

Photo-neutron spectra produced by 2.04 GeV electron incident on thick Al, Cu, Sn, and Pb targets were measured by TOF method. A Pb attenuator was placed at the middle point of the flight path to suppress #gamma# -flash signals. The thickness of the attenuator was changed from 10 cm to 30 cm for each target, and the effects of the attenuator on the neutron spectra were calculated by a combination of small changed LAHET2.7 code and ENDF-HE/VI data. Obtained neuton spectra are larger than calculated values predicted by a combination of EGS4, our modified PICA95 and LAHET2.7 codes.