[en] The N = 28 isotone "6"0Ge, T_z = -2, was produced and selected among the products of the fragmentation reaction of a "7"8Kr beam at 150 MeV/nucleon and a Be target by means of the A1900 fragment separator at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). Its decay was studied for the first time using the optical time projection chamber. The β-decay of "6"0Ge was found to be dominated by β-delayed proton emission, with a branching of ∼ 100 % and half-life T_1_/_2 = 20_-_5"+"7 ms. (orig.)

No abstract available

[en] Two new neutron-deficient isotopes, ⁶⁰Ge and ⁶⁴Se, were observed for the first time. They were produced by projectile fragmentation of a 140-MeV/nucleon ⁷⁸Kr primary beam on a beryllium target. The secondary fragments were unambiguously identified after separation in the A1900 fragment separator. The nucleus ⁶⁰Ge corresponds to the heaviest isotone of the N=28 neutron shell and it is most likely the last isotone to be observed. Lower limits of 110 and 180 ns were extracted for the half-life of ⁶⁰Ge and ⁶⁴Se, respectively. No events of ⁵⁹Ga or ⁶³As have been observed, providing very strong evidence that these nuclei are unbound with respect to proton emission. This non-observation implies an upper limit for the half-life of 43 ns for ⁵⁹Ga and ⁶³As

[en] The single-particle proton spectra of the neutron-deficient isotopes "5"0","5"2Ni, "5"6","5"8","6"0","6"2Zn, and "6"0","6"2","6"4Ge were calculated on the basis of the dispersive optical model whose parameters were extrapolated from the region of stable isotopes. The resulting parameter values lead to agreement between the total number of protons in bound states and the charge number Z of the respective nucleus. The results of the calculations are indicative of a weakly magic character of the "5"8Zn nucleus, which has a traditional magic number of N = 28 and a nearly magic number of Z = 30, and the "6"4Ge nucleus, for which N = Z = 32