| 摘要 |
PURPOSE:To measure and analyze mixed specimens of tritium and carbon 14 and find the radioactivity of nickel 63 accompanying exact radioactivity determination of tritium by using standard specimens of low relative counting efficiency and acting on three correction factors. CONSTITUTION:In order to obtain the radioactivity of tritium by an automatic efficiency tracer method, standard specimens which show sufficiently lower counting efficiency than those used by the conventional automatic efficiency tracer method must be used. But it is difficult to obtain extrapolation value when such tritium standard specimens are used. Thus, in order to overcome a difficult point, secondary regression formula I multiplied by correction factor f1 is secondary regression formula II and further the formula II multiplied by correction factor f1 is secondary regression formula III. Next, when the value which indicates counting efficiency of 100% of tritium is found by secondary regression formula III, it is corrected by correction factor f3 introduced from secondary regression formula N and final radioactivity of tritium is determined.
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