Decay spectroscopy at the two-proton drip line: Radioactivity of the new nuclides Os and W
A.D. Briscoe (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom, Accelerator Laboratory, Department of Physics, University of Jyväskylä, Jyväskylä, Finland)
; R.D. Page (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom)
; J. Uusitalo (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom, Accelerator Laboratory, Department of Physics, University of Jyväskylä, Jyväskylä, Finland); D.T. Joss (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom); M.A.M. AlAqeel (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom, Physics Department, Imam Mohammad Ibn Saud Islamic University (IMISU), P.O. Box 90950, Riyadh, Saudi Arabia); et al - Show all 64 authors
The radioactivity of Os$_{84}$ and W$_{82}$ that lie at the two-proton drip line has been measured in an experiment performed at the Accelerator Laboratory of the University of Jyväskylä. The $^{160}$Os nuclei were produced using fusion-evaporation reactions induced by a beam of 310 MeV $^{58}$Ni ions bombarding a $^{106}$Cd target. The $^{160}$Os ions were separated in flight using the recoil separator MARA and implanted into a double-sided silicon strip detector, which was used to measure their decays. The α decays of the ground state of $^{160}$Os ( = 7092(15) keV, = 97 μs) and its isomeric state ( = 8890(10) keV, = 41 μs) were measured, allowing the excitation energy of the isomer to be determined as 1844(18) keV. These α-decay properties and the excitation energy of the isomer are compared with systematics. The α decays were correlated with subsequent decays to investigate the β decays of the ground state of $^{156}$W, revealing that unlike its isotones, both low-lying isomers were populated in its daughter nuclide, $^{156}$Ta. An improved value for the half-life of the proton-decaying high-spin isomeric state in Ta$_{83}$ of 333 ms was obtained in a separate experiment using the same experimental systems with a $^{102}$Pd target. This result was employed to improve the precision of the half-life determined for $^{156}$W, which was measured as 157 ms.