Half lives of the 482.2 keV and 615.3 keV levels in 181Ta

The half lives of the excited levels at 482.2 keV and 615.3 keV in 181Ta have been measured by the delayed coincidence technique. In the nanosecond time range (482.2 keV level) the most serious sources of errors are jitter, walk and drift phenomena. To minimize those the time pick-off has been defined carefully by means of modern fast timing detectors and electronics. In the microsecond time range (615.3 keV level) the ratio of true delayed coincidences to chance coincidences influences considerably the final accuracy of the half-life measurements. It has been reduced as much as possible. From a series of independent measurements half lives of Tsub(1/2)=(10.67+-0.05) ns and Tsub(1/2)=(17.64+-0.14) μs have been deduced for the 482.2 keV and 615.3 keV levels, respectively. The results have been compared with other values published before. (orig.)