Reaction Rates for 146Sm Production in Supernovae

Correlations of the 142 Nd/ 144 Nd ratio with the Sm/Nd ratio in some meteorites have been previously explained by the-decay of long-lived 146 Sm. In order to account for these observations, a necessary production ratio for 146 Sm/ 144 Sm in the-process of 0.1{0.7 was deduced. The ratio (148 Gd(,n) 147 Gd)/(148 Gd(,) 144 Sm), which plays the dominant role in the production of 146 Sm/ 144 Sm, has been re-determined in the present paper by improved statistical model calculations. Utilization of folding potentials for current address 1 the-channel reduce the (,) rate by a factor of 3, which would enhance the production ratios, previously predicted at the lower limit of the allowed range 0.1{0.7. However, additional improvements in the treatment of nuclear level densities also reduce the (,n) rate by a factor of 0.4. Thus, in total the new cross section calculations result, at best, only in a modestly enhanced production ratio of 146 Sm/ 144 Sm.