Sup 187 Os + n Resonance Parameters in the Interval 27-500 EV Neutron Energies

摘要

The neutron total cross section for sup 187 Os, in the energy range, 27 eV to 500 eV, has been measured at the ORELA facility by the neutron time-of-flight technique, utilizing a 2.0 gm osmium sample (n = 0.008401 Os-nuclei/barn) enriched to 70.38% sup 187 Os. Measurements were performed at a 80 m flight station with an energy resolution, delta E/E, of 0.1% using a sup 6 Li glass scintillator. Resolved resonances have been analyzed by a Reich-Moore multilevel code (SAMMY) to obtain parameters for 85 resonances up to 500 eV. Preliminary determinations of the level spacing (5 eV) and s-wave strength function (3.9 x 10 exp -4 ) for sup 187 Os are in agreement with recent analyses of the osmium isotopes, made in connection with the use of the Re/Os chronometer for estimating the duration of stellar nucleosynthesis. (ERA citation 10:047760)