LEVELS OF SR85 POPULATED IN THE DECAY OF Y85 AND Y85M,
Abstract
Evidence is presented for the existence of two isomers in Y(85) with half-lives of 2.9 plus or minus 0.2-h and 4.7 plus or minus 0.2-h. Positron, photon and x-ray measurements, both singles and coincidence, were performed. No evidence was obtained for the existence of an isomeric transition between the two isomers. A tentative decay scheme for 2.9-h Y(85) is presented which includes levels in Sr(85) at 0.237 (Sr(85m), 1/2-), 0.740 (1/2-, 3/2-) and 1.152 (1/2-, 3/2-) MeV. A decay scheme for 4.7-h Y(85) is proposed with levels at 0.231 (7/2+), 0.769, (0.802), 1.263, 1.353, 1.556, 1.630, 2.118, 2.169, (2.329), 2.351 and 2.779 MeV. Consideration of the data suggests that 2.9-h Y(85) has spin and parity 1/2-, and lies approximately 0.040 MeV above 4.7-h Y(85) which has spin and parity 9/2+. The logft values suggest that most of the levels populated in the 4.7-h decay have spins and parities 7/2+, 9/2 or 11/2+, the latter being less preferred because of the photon branching ratios. Although additional experimental data are required to make possible a detailed comparison with the even parity level structure of Sr(85) as predicted by Talmi and Unna (Nucl. Phys. 19:225 (1960)), the apparent preponderance of levels with spins between 7/2 and 11/2 indicates one might expect poor agreement. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 18, 1965
- Accession Number
- AD0629576
Entities
People
- Daniel J. Horen
- W. H. Kelly
Organizations
- Naval Radiological Defense Laboratory