S- and p-wave neutron spectroscopy Xc. Intermediate structure: 88Sr

Abstract

Neutron total cross section measurements of natural Sr were made from 50–875 keV using a high resolution proton beam and the 7Li( p, n) reaction as a neutron source. These data were analyzed with the help of an R-Matrix code to extract resonance (energies and other) parameters up to about 850 keV. 2 p-1 h and particle-vibration doorway interpretation of the s-, p- and d-wave resonances is attempted in terms of the sum rule Σ γ n 2 = γ d 2. Predictions based on both of these models agree with the experimental results. As expected the p-wave resonances are stronger than either s- and d-wave structure. Theory accounts for the p-wave strength remarkably well. Possible location of the p-wave s.p. resonance is reproduced with a real potential and its damping due to the imaginary potential is calculated. More fragmentation of the strong p-wave doorways is observed than was expected for a compound nucleus so near 90Zr, but a larger strength function is observed apparently due to the p-wave giant resonance.