The Neutron Capture Cross Section of Yttrium-89

The resonance neutron capture cross section of ⁸⁹Y has been measured between 2.5 and 100 keV with the neutron capture facility at the 40-m flight station on the Oak Ridge Electron Linear Accelerator. Resonance parameters were extracted for levels below 50-keV bombarding energy. The average s-wave radiative width 〈Γγ〉_s = 115 ± 15 meV. Spin assignments were made for the 13 largest p-wave resonances from shape analysis. The average radiative width for these resonances is 〈Γγ〉_p = 307 ± 31 meV. The strong correlation bjetween p-wave reduced neutron widths and radiative width is ascribed to valence neutron effects. The magnitude of the effect is close to that estimated using the optical model formalism of the valence theory.