NEUTRON DECAY OF ISOBARIC ANALOG RESONANCES IN ZR-90

Excitation functions and angular distributions of the radiation from Zr89 following the reaction Y89(p,n) have been measured with a 56-cm3 Ge(Li) detector in the range from 5.4- to 7.8-MeV bombarding energy. At 6.00-, 6.16-, 7.28-, and 7.45-MeV bombarding energy, resonances in several neutron channels were observed which were attributed to isobaric analog states in the compound system Zr90. From an analysis of the 6.16-MeV 1- resonance in terms of Robson's theory, the level shift 86 keV was obtained which was compared with an estimate derived from the spreading width of this resonance. New states in Zr89 were identified at 1834-, 2081-, 2130-, 2220-, 2298-, 2389-, 2570-, and 2610-keV excitation energy. From a Hauser-Feshbach analysis of the -ray excitation functions and angular distributions, the spins of a number of these states and mixing ratios of -ray transitions were found. Evidence is given for a weak coupling multiplet of a g92 neutron hole coupled to the 2.18-MeV 2+ state in Zr90. © 1969 The American Physical Society.