Beta Decay Energy of Tritium

摘要: The extrapolated end point from Kurie plots of the tritium beta spectrum between 14 and 18 kev has been measured as 18.61\ifmmode\pm\else\textpm\fi{}0.02 (internal consistency) on Argonne double-lens spectrometer. Composite sources tritiated estradiol 10-hr thorium B (${\mathrm{Pb}}^{212}$) its daughters allow calibration at 25 (the "$A$" line) well some check effect source thickness line. A review other measurements, including mass difference data, average energy determination, proportional counter work, shows agreement with present magnetic spectrometer result, 18.6\ifmmode\pm\else\textpm\fi{}0.1 (this error includes estimate possible systematic effects). Two notable exceptions give lower values, 18.2 18.0 kev---one an a result. 18.6-kev decay half-life 12.43 years $ft=1137\ifmmode\pm\else\textpm\fi{}20$ sec.