Discovery of doubly magic 48Ni
In an experiment at the SISSI/LISE3 facility of GANIL, we used the projectile fragmentation of a primary 58Ni26+ beam at 74.5 MeV/nucleon with an average current of 3 &mgr;A on a natural nickel target to produce very neutron-deficient isotopes. In a 10-day experiment, 287 42Cr isotopes, 53 45Fe isotopes, 106 49Ni isotopes, and 4 48Ni isotopes were unambiguously identified. The doubly magic nucleus 48Ni, observed for the first time, is the most proton-rich isotope ever identified with an isospin projection T(z) = -4. It is probably the last doubly magic nucleus with "classical" shell closures accessible for present-day facilities. Its observation allows us to deduce a lower limit for the half-life of 48Ni of 0.5 &mgr;s.
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CEN Bordeaux-Gradignan, Le Haut-Vigneau, F-33175 Gradignan Cedex, France.
Chartier
M
Czajkowski
S
Giovinazzo
J
Pravikoff
MS
Thomas
J
de France G
de Oliveira Santos F
Lewitowicz
M
Borcea
C
Grzywacz
R
Janas
Z
Pfutzner
M