Half-life measurement for the rp-process waiting point nuclide 80Zr

X-ray bursts have been suggested as a possible site for the astrophysical rp-process. The time scale for the process is governed by beta-decay half-lives of several even-even N = Z waiting point nuclei, in particular, N = Z = 40 80Zr. A 4.1(+0.8/-0.6)-s beta(+)/EC half-life for 80Zr was determined by observing delayed 84-keV gamma rays depopulating a T(1/2) = 4-&mgr;s isomer at 312 keV in the daughter 80Y. As this half-life is lower than many previously predicted values, the calculated excessive production of A = 80 nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides.