RADIOACTIVE DECAY OF Pm$sup 143$, Pm$sup 144$, AND Pm$sup 14$$sup 6$
The decay of Pm/sup 143/, Pm/sup 144/, and Pm/sup 146/ was studied. Results on the electron-capture decay of Pm/sup 143/ and Pm/sup 144/ are in agreement with previously reported results. The results of gamma-gamma directional-correlation measurements are consistent with the spin assignments for the Nd/sup 144/ levels made by Ofer. Pm/sup 146/ (T/sub 1/2, approximately 710 days) was found to decay both by beta emission to a level of 749 kev in Sm/sup 146/ and by electron capture to levels of 453 and 1198 kev in Nd/sup 146/ The percentage branchings were 35%, 35%, and 30%, respectively. Gamma-ray transitions of 453 and 745 kev in cascade in Nd/sup 146/ and 749 kev in Sm/sup 146/ were observed. The end-point energy for the beta-decay branch was measured to be 779 kev. The beta spectrum appeared to have an allowed shape but the experimental data are not precise enough to rule out a forbidden shape. Directionalcorrelation and internal-conversion coefficient measurements were most consistent with a 3+ assignment for the 1198 kev level in Nd/sup 146/. A 2+ assignment was possible, but less likely, since the cross-over transition was absent or extremely weak. (auth)
- Research Organization:
- University of Notre Dame, Notre Dame, Ind.
- NSA Number:
- NSA-14-026267
- OSTI ID:
- 4137469
- Report Number(s):
- TID-6458
- Country of Publication:
- United States
- Language:
- English
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