Measurement of double differential neutron emission cross sections at 14.1 MeV for Ca, Mn, Co and W

Using the neutron TOF spectrometer at OKTAVIAN, double differential neutron emission cross sections at 14.1 MeV were measured for Ca, Mn, Co and W which are of interest for shielding and structural material elements of fusion reactors. Data were obtained for 16 angle points from 15 to 160 deg in the LAB system for each element, covering the secondary neutron energy region from 0.5 MeV to 15 MeV. Statistics and energy resolution of obtained data are satisfactory. The double differential cross sections in the LAB system were once converted to those in the center-of-mass system and integrated over scattering angle to obtain neutron emission spectra. Angle-differential cross sections were obtained for the elastic and discrete-inelastic scatterings whose peaks in DDX spectra could be resolved. The measured DDX data are so numerous that only their graphs are shown in this report. However, the graphs and numerical tables are given for the neutron emission spectra and the angle-differential cross sections. In the graphs, preliminary comparisons are made with evaluated data (ENDF/B-IV and JENDL-3T). The ENDF/B-IV data for Ca are satisfactory in the high energy region, but overestimate the experimental values in the low energy region. The JENDL-3T data for Mn reproduce well the angle-integrated neutron emission spectrum, though underestimation is seen in the 6-13 MeV region. It is noted that ENDF/B-IV underestimates the emission spectrum of Co in the 3-13 MeV region. The ENDF/B-IV data for W do not agree at all with the experimental spectral patterns. (author)