Decay properties of isomeric states in radium isotopes close to N = 126
Gesellschaft für Schwerionenforschung mbH, D-64220, Darmstadt, Germany
2 Institut für Physik, Johannes Gutenberg - Universität Mainz, D-55099, Mainz, Germany
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Accepted: 18 May 2004
Published online: 9 November 2004
Isomeric states in 210-215Ra have been populated by the decay of the compound nuclei 216, 220Ra produced in irradiations of 204, 208Pb with 12C at E lab = (68-136)MeV. Published values for γ-ray energies and half-lives were confirmed for 212m-215m Ra. Our data for 210m Ra agree with the γ-energies and the half-life measured at the RITU separator, University of Jyväskylä (Finland). Its decay pattern is complex. Two series of γ-rays of E γ = 96.7, 774.6, 578.0, 604.5keV and E γ = 96.7, 602.1, 750.5, 604.5keV were observed. A half-life of ( 2.36±0.04)μs was measured. The isomeric state is attributed to an 8+ state at E * = 2053.8keV. A previously unknown isomeric state was assigned to 211m Ra. It has a half-life of (4.0±0.5)μs and it decays by emission of γ-rays with energies of 396.1keV and 802.0keV. It is attributed to a 13/2+ state at E * = 1198.1keV.
© Società Italiana di Fisica and Springer-Verlag, 2004