Nuclear structure studies via neutron interactions. Progress report, 1 July 1994--30 June 1995

Abstract

Neutron total cross section measurements of {sup 122}Sn has been analyzed over the energy range 0.013 to 0.310 MeV. The R - matrix analysis has resulted in resonance and average parameters which provide for a complete representation of the neutron entrance the s{sub 1/2}, p{sub 1/2}, and p{sub 3/2} contributions. The s - and p - neutron strength functions have been determined to be 0.123 {plus_minus} 0.023 and 2.0 {plus_minus} 0.200, respectively (in units of 10{sup {minus}4}). Limits are placed on level spacings and strength functions for the individual partial wave components. The s - wave potential scattering radius has been determined to be 6.3 {plus_minus} 0.1 fm. Average scattering functions, deduced from the average parameters, have been used to determine the real well depth of an optical model potential which reproduces these functions. We find, as have others, that the real well depth is parity dependent. Two computer codes were developed: (1) a minimization program for finding parameters of a dispersive optical model which reproduce the high resolution data of the ORELA facility, and (2) an X-windows graphical user interface has been developed to permit interactive resonance analysis of the neutron total cross section data using analysis-and-minimization codes developed previously. These will contribute to the more routine analysis of ORELA data.