Alpha-decay study of 218U; a search for the sub-shell closure at Z = 92

Research paper by A. -P. Leppänen, J. Uusitalo, S. Eeckhaudt, T. Enqvist, K. Eskola, T. Grahn, F. P. Heßberger, P. T. Greenlees, P. Jones, R. Julin, S. Juutinen, H. Kettunen, P. Kuusiniemi, M. Leino, P. Nieminen, et al.

Indexed on: 22 Jun '05Published on: 22 Jun '05Published in: The European Physical Journal A


Neutron-deficient uranium isotopes were studied via α spectroscopic methods. A low-lying α-decaying isomeric state was found in 218U. The new isomeric state was assigned spin and parity Iπ=8+. The isomer decays by α emission with an energy E = 10678(17)keV and with a half-life T1/2 = (0.56+0.26-0.14)ms. The known alpha-decay properties of the ground state of 218U was measured with improved statistics. The ground-state α-decay has an energy E = 8612(9)keV and a half-life T1/2 = (0.51+0.17-0.10)ms.