Eur. Phys. J. A (2004) 22: 253-260
https://doi.org/10.1140/epja/i2003-10233-9

Decay properties of isomeric states in radium isotopes close to N = 126

¹ Gesellschaft für Schwerionenforschung mbH, D-64220, Darmstadt, Germany
² Institut für Physik, Johannes Gutenberg - Universität Mainz, D-55099, Mainz, Germany

^* e-mail: f.p.hessberger@gsi.de

Received: 28 October 2003
Accepted: 18 May 2004
Published online: 9 November 2004

Abstract

Isomeric states in ^210-215Ra have been populated by the decay of the compound nuclei ^{216, 220}Ra produced in irradiations of ^{204, 208}Pb 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.