Identification and halflife measurement of 100Sn and neighbouring nuclei

We report the first observation of the doubly-magic nucleus 100Sn. This isotope was produced by nuclear fragmentation of 124Xe projectiles at 1095 A MeV using the heavy-ion synchrotron SIS at GSI, Darmstadt. The projectile fragments were separated in flight with the projectile fragment separator FRS and identified by measuring event by event magnetic rigidity, the time of flight and the energy deposition. The analysis of the decay events following the implantation of the fragments into a stack of Si detectors revealed for the first time the halflives of the isotopes 100Sn, 104Sb, 105Sb. (orig.)