AN EXPERIMENTAL STUDY OF THE INTEGRAL PROPERTIES OF U235 AND Pu239 IN AN INTERMEDIATE ENERGY SPECTRUM, AND COMPARISON WITH THEORETICAL PREDICTION

摘要

This is an area where the fissile nuclide cross-section data, particularly that for radiative capture, are still inadequately defined, as evidenced by the considerable discrepancies between various determinations. The difficulties stem from the problems of resolving and analysing the properties of closely spaced resonances and particularly in separating the fission and capture contributions. Prom the parameters of the resolved resonances, the distributions of the partial widths must be derived in order to provide a sound basis for the calculation of the averaged properties in the unresolved region, which constitute a significant part of the region of interest. The correct assignment of the fission and capture widths and their distributions is also necessary for the calculation of the spectrum-average capture to fission ratio (a), which has an important bearing on conversion and breeding ratios.