Half-Life Measurement for therp-Process Waiting Point NuclideZ80r

X-ray bursts have been suggested as a possible site for the astrophysical $\mathrm{rp}$-process. The time scale for the process is governed by $\ensuremath{\beta}$-decay half-lives of several even-even $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}Z$ waiting point nuclei, in particular, $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40$ ${}^{80}\mathrm{Zr}$. A $4.1({+0.8}{\ensuremath{-}0.6})\ensuremath{-}\mathrm{s}$ ${\ensuremath{\beta}}^{+}/\mathrm{EC}$ half-life for ${}^{80}\mathrm{Zr}$ was determined by observing delayed 84-keV $\ensuremath{\gamma}$ rays depopulating a ${T}_{1/2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4\ensuremath{-}\ensuremath{\mu}\mathrm{s}$ isomer at 312 keV in the daughter ${}^{80}\mathrm{Y}$. As this half-life is lower than many previously predicted values, the calculated excessive production of $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}80$ nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides.