NEW YTTRIUM ISOMERS OF MASSES 86 AND 90

Cyclotron bombardment of Rb with alpha particles and Sr with deuterons yield two new yttrium activities. Y/sup 86m/ decays with a half life of 49.0 plus or minus 1.5 min. The isomer is supported by a highly converted 7.2 kev isomeric transition followed by a 210 kev gamma ray having a conversion coefficient e/ gamma = 0.06 plus or minus 0.01. Y/sup 90m/ has a half life of 3.19 plus or minus 0.06 hr, decaying to the Y/sup 90/ ground state with emission of two gamma rays: 476 kev, e/ gamma = 0.10 plus or minus 0.02; and 203 kev, e/ gamma = 0.036 plus or minus 0.007. Spin and parity assignments are made for the Y/sup 90/ levels. (auth)