DECAY OF Y$sup 85$ ISOMERS
Two isomers of Y/sup 85/ were identified and their half lives determined as 2.68 plus or minus 0.05 h and 5.0 plus or minus 0.2 h. Measurements were made by means of successive timed daughter separations and by direct observation of the decay of radiations from yttrium. Both isomers decay independently by positron emission. The 2.68-h isomer decavs to the 70-min Sr/sup 85m/-- while the 5.0-h isomer decays to the 64-d Sr/sup 85/. No isomeric transition was observed. Positron spectra were measured with a BETA -ray spectrometer. The spectrum for the 2.68-h isomer has an end-point energy of 1.54 plus or minus 0.02Mev, and the components of the 5-h isomer have end points of 2.24 plus or minus 0.01, 2.01 plus or minus 0.01, and 1.1 plus or minus 0.1 Mev. Conversion electron measurements disclosed a 503-kev transition, with a half life of 2.68 h, K conversion coefficient of 1.9 x 10/sup -3/, and K/L ratio of approximates 10. The gamma spectrum for the Y/sup 89/ isomeric mixture is complex. The observed transitions are: 503 and 925 kev from the 2.68-h isomer, and 231, 700, 772, (1030), from the 5.0-h isomer. Sum-coincidence spectra showed summation of the following radiations: (231-- 511), (503-cidence measurements showed that the 2.01-Mev position group is coincident with the 231-kev gamma ray and that the 1.54-Mev positron from the 2.68-h isomer is in coincidence with the 503-kev gamma ray. The 5.0-h isomer of Y/sup 85/ is 3.26 Mev above the ground level of Sr/sup 85/ while the 2.68-h isomer is at 3.30 Mev, thus being 40 plus or minus 30 kev higher. Spins of 9/2/sup +/ and 1/2/sup -/ were assigned to the 5.0-h and 2.68-h isomers, respectively. A partial decay scheme is presented. (auth)
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- NSA Number:
- NSA-18-002927
- OSTI ID:
- 4145565
- Report Number(s):
- BNL-7181; 0031-899X
- Journal Information:
- Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Vol. Vol: 132; Other Information: BNL-7181. Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- United States
- Language:
- English
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