test of half-life predictions for neutron-rich isotopes of refractory elements
نویسندگان
چکیده
Beta-decay gross properties of neutron-rich isotopes 104 Y and Tc produced in 25 MeV proton-induced fission of U have been measured. Decays of 104 Y with a half-life of 180"60 ms and of Tc with a half-life of 150"30 ms are 112,113,114 Ž . reported for the first time. Beta-delayed neutron emission probabilities of Tc are determined as 1.5"0.2 %, Ž . Ž . 2.1"0.3 % and 1.3"0.4 %, respectively. Comparison of the observed P values with a recent theoretical calculation n Ž . based on deformed quasiparticle random phase approximation QRPA shows good overall agreement for Tc isotopes. However, comparison of beta-decay half-lives of neutron-rich isotopes of Y to Rh with the QRPA model and the refined gross theory shows only modest agreement, pointing to inadequate treatment of structure of these very neutron-rich nuclei lying in a region of rapidly changing deformation. q 1999 Elsevier Science B.V. All rights reserved.
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