Abstract
The half-life of was determined by following the decay of and for 14 yr. Mixed sources containing and and pure sources of and were prepared and their γ-ray spectra were measured with a Ge spectrometer once or twice a year. Counts in the 1157.0-keV γ-ray photopeak of and the 1173.2- and 1332.5-keV γ-ray photopeaks of were used for this measurement. From the decay of the and activity ratios, the half-life of was determined. Using a value of 5.2711±0.0004 yr for half-life, we determined the half-life of as 58.9±0.3 yr. Special efforts were made to check for systematic errors and these were found to be negligible within the quoted uncertainty.
- Received 12 June 2006
DOI:https://doi.org/10.1103/PhysRevC.74.065803
©2006 American Physical Society