First observation of ${}^{59}\mathrm{Ge}$

In an experiment at the A1900 spectrometer of the National Superconducting Cyclotron Laboratory at Michigan State University the new isotope ${}^{59}\mathrm{Ge}$ was identified and the cross section for production of the most neutron-deficient ${}^{59-62}\mathrm{Ge}$ isotopes in the fragmentation of a ${}^{78}\mathrm{Kr}$ beam at 150 MeV/nucleon measured. This experimental information is relevant for the hunt of new two-proton emitters in the region above the doubly-magic ${}^{48}\mathrm{Ni}$.

Figure 1

Schematic of the experimental configuration. Drawing not to scale. See text for details.

Figure 2

Identification plot for the ion-optics setting of the A1900 optimized for ${}^{59}\mathrm{Ge}$. See text for details.

Figure 3

Waveforms of signals giving the $\mathrm{\Delta }E$ (red, negative), ToF1 (blue, positive, left), and ToF2 (green, positive, right) ion-identification information for the three events of ${}^{59}\mathrm{Ge}$ acquired by DAQ2 oscilloscope. See text for details.

Figure 4

Cross section for the production of neutron-deficient germanium isotopes in the fragmentation of a ${}^{78}\mathrm{Kr}$ beam on a beryllium target. Data from this work [(red) circles] are compared to literature data from the previous A1900 experiment [9] (black triangles) and EPAX3 calculations [15] [(blue) squares]. Only statistical uncertainties are shown for the data from this work.