Beta decay along the N=Z line and its relevance in rp-process and X-Ray bursts

Nucleosynthesis in Type I X-ray bursts (XRB) proceeds eventually through the rp-process near the proton drip-line. Several N=Z nuclei act as waiting points in the reaction network chain. Astrophysical calculations of XRB light curves depend upon the theoretical modelling of the beta decays of interest, with the N=Z waiting points Ge-64, Se-68, Kr-72, Sr-76, and their second-neighbours N=Z+2 being key nuclei in this context. We have carried out different experimental campaigns at ISOLDE (CERN) to determine the B(GT) distributions, in the decay of several N=Z, N=Z+2 and their daughters, of particular relevance in rp-process calculations. To this aim the Total Absorption Spectroscopy technique is applied. Here we present results on the beta decay of Ga-64 and the status of the analysis of Ge-64. Our results provide benchmarks for testing and constraining models under terrestrial conditions that can be used later for predictions in stellar environments.