Discovery of rare neutron-rich Zr, Nb, Mo, Tc, and Ru isotopes in fission: Test of β half-life predictions very far from stability

J. Äystö; A. Astier; T. Enqvist; K. Eskola; Z. Janas; A. Jokinen; K.-L. Kratz; M. Leino; H. Penttilä; B. Pfeiffer; J. Zylicz

doi:10.1103/PhysRevLett.69.1167

Discovery of rare neutron-rich Zr, Nb, Mo, Tc, and Ru isotopes in fission: Test of β half-life predictions very far from stability

J. Äystö, A. Astier, T. Enqvist, K. Eskola, Z. Janas, A. Jokinen, K.-L. Kratz, M. Leino, H. Penttilä, B. Pfeiffer, and J. Zylicz

Phys. Rev. Lett. 69, 1167 – Published 24 August 1992

Abstract

In experiments employing fast ion-guide-based on-line mass separation we have identified six new, rare nuclides of highly refractory elements produced in the fission of ${}^{238}U$ by 20-MeV protons. The new isotopes ${}^{105}{Zr}$ , ${}^{107}{Nb}$ , ${}^{109}{Mo}$ , ${}^{110}{Mo}$ , ${}^{113}{Tc}$ , and ${}^{115}{Ru}$ were identified through (β, $K_{α}$ x-ray) coincidences and β-delayed γ decay. The observed β half-lives range from 130 ms to approximately 1 s. All our recent β half-life data are compared with predictions of the deformed quasirandom-phase-approximation model. The main uncertainty is found to be the inaccuracy of the decay energy predictions.

Received 17 April 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.1167

Authors & Affiliations

J. Äystö, A. Astier, T. Enqvist, K. Eskola, Z. Janas, A. Jokinen, K.-L. Kratz, M. Leino, H. Penttilä, B. Pfeiffer, and J. Zylicz

Department of Physics, University of Jyväskylä, Jyväskylä, Finland
Institute de Physique Nucléaire, Uníversité Claude Bernard, Villeurbanne, France
Department of Physics, University of Helsinki, Helsinki, Finland
Department of Experimental Physics, Warsaw University, Warsaw, Poland
Institut für Kerchemie, Universität Mainz, Mainz, Germany