The Importance of Delayed Fission in the Production of very Heavy and Superheavy Elements

Abstract

Recent advances in the calculation of fission barriers and in the experimental determination of beta strength functions make it possible to derive reliable estimates of the effect of beta-delayed fission in the decay of very heavy nuclides far from the line of beta-stability. The model presented here is used to calculate the amount of delayed fission during the decay back of nuclides produced in the astrophysical decay r -process. An interesting feature of these calculations is that they reproduce the reversal of the odd-even effect found for the yield of beta-stable nuclides obtained in the thermonuclear explosions. The preliminary results from the r -process calculations indicate that the effect of delayed fission has to be considered when the yield of very heavy beta stable nuclides from this process is estimated.