Assessment of nuclear data for copper and silicon by neutron spectra in these piles

As a part of the series of nuclear data assessment for structural materials for fission and fusion reactors at KURRI, neutron spectra from a few keV to a few MeV in both spherical piles of Cu and Si were measured by the time-of-flight method using an electron linac. The measured spectra were compared with the calculated ones by one dimensional Sn code with two evaluated nuclear data files, ENDF/B-IV and JENDL-2. From these intercomparisons, it can be seen that: (1) ENDF/B-IV for Cu gives better results in general than JENDL-2 (however, there still exists a little discrepancy between the calculated spectrum by ENDF/B-IV and the measured); and (2) both nuclear data files for Si afford rather poor prediction of the spectrum in the Si pile