Eur. Phys. J. A (2005) 25: 335-338
https://doi.org/10.1140/epjad/i2005-06-192-y

ENAM 2004

Discovery of ⁶⁰Ge and ⁶⁴Se

¹ National Superconducting Cyclotron Laboratory, 48824, East Lansing, MI, USA
² Department of Physics & Astronomy, Michigan State University, 48824, East Lansing, MI, USA
³ Department of Chemistry, Michigan State University, 48824, East Lansing, MI, USA

^* e-mail: stolz@nscl.msu.edu

Received: 17 January 2005
Accepted: 28 April 2005
Published online: 15 July 2005

Abstract

Very neutron-deficient fragments 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. Three events of ⁶⁰Ge and four events of ⁶⁴Se have been observed for the first time, making ⁶⁰Ge the heaviest known isotone of the N = 28 neutron shell. No events of ⁵⁹Ga and ⁶³As have been observed providing very strong evidence that these nuclei are unbound with respect to proton emission.