Nuclear Data Sheets for A=218

Abstract

The evaluated data are presented for 11 known A=218 nulcides (Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th, Pa and U). For 218Pb, 218Bi, 218At and 218Pa, data are available only for the ground states. For 218U, only the g.s. and a high-spin isomer are known, with no data on γ-ray transitions available. For 218Po, ten excited states are known from 218Bi decay, with no knowledge on the multipolarities of gamma-ray transitions. For 218Th, five excited states in the g.s. band are known from an in-beam γ-ray study. Data on level half-lives, multipolarities and mixing ratios of gamma transitions is generally lacking for A=218 nuclei. The static magnetic dipole moment has been measured for only an isomer in 218Fr. With the exception of a new nuclide, 218Pb, and measurements of half-lives of ground states of a few nuclides of A=218 and A=222, no substantial structure information has become available since the previous evaluation in 2006. Q values are adopted from 2017Wa10 (AME-2016). The present evaluation supersedes the previous A=218 ENSDF evaluations, 2006Ja03, 1995El08, 1987El12 and 1977To13. This evaluation was carried out as part of a joint IAEA-ICTP workshop for Nuclear Structure and Decay Data, organized and hosted by the IAEA, Vienna, and ICTP, Trieste, October 15–26, 2018.