Direct observation of long-lived isomers in $^{212}$Bi
Abstract
Long-lived isomers in 212Bi have been studied following 238U projectile fragmentation at 670 MeV per nucleon. The fragmentation products were injected as highly charged ions into the GSI storage ring, giving access to masses and half-lives. While the excitation energy of the first isomer of 212Bi was confirmed, the second isomer was observed at 1478(30) keV, in contrast to the previously accepted value of >1910 keV. It was also found to have an extended Lorentz-corrected in-ring halflife >30 min, compared to 7.0(3) min for the neutral atom. Both the energy and half-life differences can be understood as being due a substantial, though previously unrecognised, internal decay branch for neutral atoms. Earlier shell-model calculations are now found to give good agreement with the isomer excitation energy. Furthermore, these and new calculations predict the existence of states at slightly higher energy that could facilitate isomer de-excitation studies.
Keywords
Cite
@article{arxiv.1306.0475,
title = {Direct observation of long-lived isomers in $^{212}$Bi},
author = {L. Chen and P. M. Walker and H. Geissel and Yu. A. Litvinov and K. Beckert and P. Beller and F. Bosch and D. Boutin and L. Caceres and J. J. Carroll and D. M. Cullen and I. J. Cullen and B. Franzke and J. Gerl and M. Górska and G. A. Jones and A. Kishada and R. Knöbel and C. Kozhuharov and J. Kurcewicz and S. A. Litvinov and Z. Liu and S. Mandal and F. Montes and G. Münzenberg and F. Nolden and T. Ohtsubo and Z. Patyk and W. R. Plaß and Zs. Podolyák and S. Rigby and N. Saito and T. Saito and C. Scheidenberger and E. C. Simpson and M. Shindo and M. Steck and B. Sun and S. J. Williams and H. Weick and M. Winkler and H. -J. Wollersheim and T. Yamaguchi},
journal= {arXiv preprint arXiv:1306.0475},
year = {2013}
}
Comments
published in PRL 110, 122502