Resonance parameters, capture. gamma. -rays and reaction mechanism in /sup 98/ /sup 100/Mo + n

Abstract

In recent years the mechanism of the neutron capture reaction has found wide interest due to the detection of ''non-statistical'' effects. Among the most distinct examples for non-statistical effects in resonance neutron capture are the strong p-wave resonances in the Mo isotopes /sup 92/Mo and /sup 98/Mo. Especially in the case of /sup 98/Mo, it has been shown that the large partial radiative widths can be quantitatively explained on the basis of a simple version of the valence model. Like /sup 98/Mo, also the neighboring isotope /sup 100/Mo shows strong p-wave resonances at low neutron energies. Therefore, /sup 100/Mo provides another interesting test case for the validity of the valence model. Thus neutron resonances in /sup 100/Mo were studied at the Oak Ridge electron linear accelerator time-of-flight facility. The transmission of two oxide samples (97.4% /sup 100/Mo) was measured at an 80 m flight path and the neutron capture cross section was measured at 40 m. Resonance analysis yielded parameters of 123 resonances. Capture ..gamma..-ray spectra from 11 resolved resonances have been measured with a Ge(Li)-detector at a 10 m flight path. Contrary to the neighboring nuclei, partial radiative widths of strong p-wave resonances are not in agreement with valence model predictions