Mass Measurement on the rp-Process Waiting Point $^{72}Kr

With the aim of improving nucleosynthesis calculations, we performed for the first time, a direct high-precision mass measurement on the waiting point in the astrophysical rp-process $^{72}$Kr. We used the ISOLTRAP Penning trap mass spectrometer located at ISOLDE/CERN. The measurement yielded a relative mass uncertainty of $\deltam/m = 1.2 \times 10^{−7}$. In addition, the masses of $^{73}$Kr and $^{74}$Kr were measured directly with relative mass uncertainties of $1.0 \times 10^{−7} and 3 \times 10^{−8}$, respectively. We analyzed the role of $^{72}$Kr in the rp-process during X-ray bursts using the ISOLTRAP and previous mass values of $^{72−74}$Kr