The problem of unknown parameters in neutron resonance theory

In this thesis, three problems concerned with the estimation of unknown resonance parameters in slow neutron spectroscopy are treated, fhe average level spacing < D > as a function of nuclear excitation energy E can he calculated by considering the nucleus as a gas of free fermions and then including corrections for the interactions present in actual nuclei. In Chapter II, the correction parameters used for this purpose by Gilbert and Cameron (1965) are readjusted so that excellent agreement with the observed level spacings is obtained. This work, described in section lie is the original work of the candidate and has been previously published (Cook, Ferguson and Musgrove 1967). The improved parameters codify all experimental masses as well as level spacings. Chapter III deals with the problem of inferring the thermal neutron cross section when no information is available about the nucleus in question. The original contribution of the candidate in sections Illb-e has been previously published (Musgrove 1968a). Statistical methods were used to obtain the mean and variance of thermal cross sections on the basis of a uniform sequence of levels and on a more exact model where the distribution of level spacings and reduced neutron widths are taken into account.