Effect of radionuclide impurities on activity calibration

Equations for the calculation of the correction for radionuclide impurities are derived, and numerical values of the corrections are given for all nuclides important from the practical point of view. It is shown that the impurity contents can be determined from variations of the slope of the extrapolated straight line and from variations of the calibration constants of the 4π-γ ionization chamber. The sensitivity of these methods lies within 0.3 and 1.6% (P=99) even for pure β-emitter impurities. (author). 1 fig., 2 tab., 6 refs