Beta-decay study of neutron-rich isotopes of Bromine and Krypton

Short-lived neutron-rich nuclei including 93 Br, 93 Kr and 94 Kr were produced in proton-induced fission of 238 U at the HRIBF in Oak Ridge. Their beta decay was studied by means of a high resolution on-line mass separator and beta-gamma spectroscopy methods. The half-life of 93Br T1/2 = 152(8) ms and beta-delayed branching ratio of Pn = 53-8+11 may be compared to the previously reported values of T1/2 = 102(10) ms and Pn = 68(7)%. At the same time the half-life of 94Kr T1/2 = 227(14) ms and B-delayed branching ratio of Pn = 1.9+0.6-0.2 % of 93Kr are in very good agreement with literature values. The decay properties of 93Br include four new gamma transitions following beta-delayed neutron emission.