Branching ratio of 133Sb decay to 133Te isomers

Abstract Antimony samples were quickly separated from fission products and, after a short decay period, Te daughters were isolated and their γ rays observed with a Ge(Li) detector. The fractions of decay of 2·7 min 133 Sb to 12·5 min 133 g Te and 55 min 133 m Te were found to be 0·58±0·06 and 0·42±0·06, respectively. The cumulative yield of 133 Sb in thermal neutron fission of 235 U was measured as 1·7±0·4 per cent. An upper limit of 0·29 per cent was determined for the yield of an 11 sec 134 Sb in thermal-neutron fission of 235 U.