Nuclear Data Sheets for A=244

Abstract

Available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass numbers A=244 have been compiled and evaluated. The adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are quoted. Unexpected or discrepant experimental results are also noted. Information provided in 244U is tentative as it from the the possible production in the study of 1960Di03 of debris of the first large-scale thermonuclear test (Ivy Mike) of November 1, 1952 in the Pacific Ocean. No new data are available for 244Np and the information for g.s Jp is tentative. More experiment work is needed for 244Np as theoretical work suggest an isomer with Jp=7− and g.s with Jp=2+. In 244Pu, a new K isomer was identified and in addition rotational bands built on the isomer have been observed via the deep inelastic excitation. In 244Am, specifically in the (d,p) transfer reaction and in the (n,g ) secondary g ’s, there are a large number of gammas that are unplaced. Since its last measurement in 1966, the electron capture dataset has been updated with a tentative partial level scheme for 244Cm which also provided a new half life measurement for 244Bk. In 244Fm, a fusion evaporation experiment measured the half life and provided upper limit for the SF, a and EC branching. A summary and compilation of the discovery of various isotopes in this mass region is given in 2013Fr02 (244Np, 244Pu, 244Am, 244Cm, 244Bk, and 244Cf), 2011Me01 (244Es), and 2013Th02 (244Fm). This work supersedes the 2003 evaluation by Y.A. Akovali (2003Ak04).