New superheavy element isotopes: ²⁴²Pu(⁴⁸Ca,5n) ²⁸⁵114

Phys Rev Lett. 2010 Oct 29;105(18):182701. doi: 10.1103/PhysRevLett.105.182701. Epub 2010 Oct 26.

Abstract

The new, neutron-deficient, superheavy element isotope ²⁸⁵114 was produced in ⁴⁸Ca irradiations of ²⁴²Pu targets at a center-of-target beam energy of 256 MeV (E*=50 MeV). The α decay of ²⁸⁵114was followed by the sequential α decay of four daughter nuclides, 281Cn, 277Ds, 273Hs, and 269Sg. 265Rf was observed to decay by spontaneous fission. The measured α-decay Q values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The²⁴²Pu (⁴⁸Ca,5n²)²⁸⁵114 cross section was 0.6(-0.5)+0.9 pb.