Testing the mass surface of the nuclear chart with ISOLTRAP

The atomic nucleus is pictured as a system of bound nucleons. The mass of each nuclide results from the sum of the masses of the nucleons minus the binding energy of the system. The mass surface of the nuclear chart is built from the masses of all stable and radioactive nuclides. On this surface nuclear structure effects are seen as sudden irregularities. Additionally, nucleosynthesis and nuclear structure models are constrained by accurately known masses of nuclei. Precise mass measurements are routinely carried out by the online Penning-trap mass spectrometer ISOLTRAP, based at the radioactive ion-beam facility ISOLDE/CERN. New mass investigations of ${}^{69,70}$As, ${}^{49-51}$Sc and ${}^{72,73}$Br were performed during the latest experiment campaigns. The measurements were accomplished by using multi-reflection time-of-flight mass spectrometry and the Penning-trap based time-of-flight ion-cyclotron-resonance detection technique. The masses of ${}^{69,70}$As and ${}^{49-51}$Sc were previously known only through their $\beta$ decay Q-values. The new mass data provides an important test of the nuclear models in this region of the mass surface. This contribution will present results of the aforementioned measurements and discuss the impact of the refined mass values on the neighbouring isotopes.