Production, identification, and halflife measurement of ¹⁰⁰Sn

We report the first observation of the doubly-magic nucleus ¹⁰⁰Sn. The 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 the magnetic rigidity, the time of flight and the energy deposition. After identification the ions were implanted into a silicon detector stack and the decay was studied. We report preliminary results of the halflife determination.