Investigation of nuclei near N = 82 and Z = 64 VIA radioactive decay of high-spin isomers
An island of very high spin isomers was found recently in neutron-deficient Gd-Lu nuclei near the N = 82 closed shell in (H.I.,xn) measurements. This exciting discovery has led to a large number of experiments trying to identify the structures of these isomers and the nuclei in which they occur. These attempts have been helped in many instances by available spectroscopic information at low excitation energies. A systematic investigation of the low-lying structure of nuclei near N = 82 and Z greater than or equal to 64 was carried out. Heavy-ion beams were used to produce proton-rich isotopes which were then transported, with the use of gas-jet systems, to shielded areas where singles and coincidence ..gamma..-ray measurements could be made. Earlier investigations dealt with the decay of terbium (/sup 146 -149/Tb) and dysprosium (/sup 147 -152/Dy) nuclei. During the past two years the research program was extended to holmium nuclides (A less than or equal to 152) produced in /sup 10/B bombardments of samarium. Two new isotopes, /sup 149/Ho and /sup 148/Ho, were identified. The decay data of 21-s /sup 149/Ho supplement in-beam results and locate the hg//sub 2/ neutron state in /sup 149/ Dy to be at 1091 keV. The most intense ..gamma..-ray associated with 9-s /sup 148/Ho has an energy of 1688 keV. It is possibly the first-excited to ground-state transition in /sup 148/Dy. Recent in-beam measurements have shown that the first-excited state in /sup 146/Gd is, unespectedly, 3/sup -/ in contrast to doubly evenN = 82 nuclei below gadolinium where it is 2/sup +/. It would be interesting to determine whether the 1688-keV level in /sup 148/Dy, the next nucleus in this isotonic series, is 2reverse arrow or 3/sup -/ in character. 12 references.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6313489
- Report Number(s):
- CONF-790323--1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
A=90-149
Experimental-- Energy Levels & Transitions-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BETA DECAY
DATA
DATA FORMS
DECAY
DYSPROSIUM ISOTOPES
ENERGY LEVELS
EXPERIMENTAL DATA
GRAPHS
HIGH SPIN STATES
HOLMIUM ISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOTOPES
NUCLEI
NUMERICAL DATA
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
TERBIUM ISOTOPES