UBC Theses and Dissertations
Inelastic neutron scattering to isomeric levels Truant, Paul Thomas
In order to use inelastic neutron scattering to isomeric levels as a tool in evaluating nuclear strength functions, we derive the appropriate evaporation formulae; both with and without corrections for the statistical fluctuations of the compound nucleus reduced partial widths. The isomeric activity induced by inelastic neutron scattering is calculated for: In¹¹⁵, Rh¹º³, Y⁸⁹ and Nb⁹³; and is used to illustrate the effect of the fluctuation corrections and the level spin and parity assignments, on the calculated cross sections. Comparison with experimental data is used to infer probable assignments of level spins and parities for In¹¹⁵ and Rh¹º³. We also show that for any nucleus lying near an even or odd partial wave strength function resonance, the inelastic neutron scattering cross section to isomeric levels will be directly proportional to l ≥ 2 strength functions. In the examples cited above, it is the d-wave strength function; and the isomeric cross section shows the corresponding dependence on the optical model potential, being directly proportional to the strength of the imaginary part and insensitive to the real part of the potential.
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