Beta-decay half-lives of very neutron-rich Kr to Tc isotopes on the boundary of the r-process path : an indication of fast r-matter flow

The beta-decay half-lives of 38 neutron-rich isotopes from Kr-36 to Tc-43 have been measured; the half-lives of Kr-100, Sr103-105, Y106-108, Zr108-110, Nb-111,Nb-112, Mo112-115, and Tc-116,Tc-117 are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A approximate to 110 region. A revised model based on the second generation gross theory of beta decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.