SPROCESS Studies: Branching and the Time Scale
Abstract
The theory of sprocess heavyelement formation is reformulated to allow for competition between beta decay and neutron capture at various nuclei along the path. Solutions to the resulting branching network equations are presented (under the assumption of constant temperature and neutron flux) that do not require steady flow for the neutron current. Using the exponential exposure distribution p( ) = G exp ( T/ 7o) and recently calculated temperaturedependent betadecay rates, comparison of several key branches yields the following average conditions for the solarsystem sprocess enviroument: T 3.1 x l0 K, n 1.6 x l0 neutrons cm  . For T0 = 0.25 n mb 1 we find that about 4.8 neutron captures per exposed iron seed are required over a time of the order of a few thousand years for synthesis of the bulk of the solarsystem sprocess material, with an average neutron capture time 10 years (for a 500 mb). Subject headings: abundances  nucleosynthesis  stars: interiors
 Publication:

The Astrophysical Journal Supplement Series
 Pub Date:
 May 1976
 DOI:
 10.1086/190373
 Bibcode:
 1976ApJS...31...33W