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{beta}{sup +} decay and cosmic-ray half-lives of {sup 143}Pm and {sup 144}Pm

Description: The positron decay partial half-lives of {sup 143}Pm and {sup 144}Pm are needed to assess the viability of elemental Pm as a cosmic-ray clock. We have conducted experiments to measure the {beta}{sup +} branches of these isotopes; we find {beta}{sup +} branches of these isotopes; we find {beta}{sup +} branches of <5.7 {times}10{sup {minus}8} for {sup 143}Pm and <8{times}10{sup {minus} 7} for {sup 144}Pm. Through these branches are a factor of 20 lower than the previous experimental limits, the resulting partial half-lives are still too uncertain to permit any firm conclusions.
Date: April 12, 1993
Creator: Hindi, M. M.; da Cruz, M. T. F.; Larimer, R. M.; Lesko, K. T.; Norman, E. B.; Sur, B. et al.
Partner: UNT Libraries Government Documents Department


Description: Phase transfer of Pr by electrolysis at a lithium amalgam cathode was found to be linear with time for fixed electrolysis conditions. The rate of electrolysis of Pr decreased with increasing lithium citrate concentration. Extraction of Pm from Pm--Gd mixtures with saturated lithium amalgam was found to vary with virtually any change in electrolyte composition. The Pm extraction was first order with respect to Pm concentration, but the extraction rate decreased with increasing excess citrate concentration. The presence of Gd did not affect the extraction of Pm very much at Gd concentrations less than 0.1 M, but at higher concentrations of Gd the amount of Pm extracted was diminished. The results indicate that the exchange reactions are very fast and it may be possible to interpret rate data in terms of equilibria in the electrolyte phase. (auth)
Date: January 1, 1963
Creator: Onstott, E.I.; Smyrl, W.H. & Macander, R.F.
Partner: UNT Libraries Government Documents Department