Final results of the internal /sup 235/U sample intercomparison and the half-life of /sup 234/U

Finalized values were recieved from all laboratories which contributed samples to the /sup 235/U mass intercomparison carried out at Argonne National Laboratory. A least-squares fit was made which included the quoted masses and the absolute low-geometry and relative 2..pi..-geometry alpha data as well as the relative fission ratios measured at ANL. Correlations between the measured values were taken into account. The values quoted by the contributing laboratories were found to be within +-0.35% of the values obtained from the LS fit. Very precise values for the isotopic composition were known for two of the sample materials which permitted a determination of the half-life of /sup 234/U. The value obtained is T/sub 1/2/ = (2.457 +- 0.005) x 10/sup 5/ years. Including this value in the present data base results in a current best value of T/sub 1/2/ = (2.4566 +- 0.0044) x 10/sup 5/ years. 6 references, 2 figures, 6 tables.