alpha decay of (273)110: Shell closure at N=162

Abstract

In bombardments of Pu-244 with S-34 we discovered the alpha-decaying nuclide (273)110. We conducted an extensive off-line search of the raw data for event sequences which fit the expected pattern of implantation in a position-sensitive detector and subsequent decay of (273)110 and its descendants. We observed one three-member sequence of genetically linked alpha decays, resulting in E(alpha)=11.35 MeV, a half-life of 0.3(-0.2)(+1.3) ms, and a production cross section of about 0.4 pb for (273)110. Other possible (273)110 event chains were also observed. The measured a-particle energy for the N=163 nuclide (273)110 provides direct evidence for a neutron shell closure at N=162.