Mott-Scattering Analysis of Longitudinal Polarization of Electrons fromCo60

Mott scattering has been used to analyze the degree of longitudinal polarization of beta particles emitted from radioactive nuclei. The reliability of this method and the influences of the various systematic errors associated with this method on the accuracy of the measurement have been investigated in detail and are discussed. On the basis of a linear extrapolation of the inverse of the Mott asymmetry to zero scatterer thickness, the polarization of 194-kev electrons from ${\mathrm{Co}}^{60}$ was found to be $-(0.994\mathrm{}\pm 0.057)\frac{v}{c}$ with all known corrections applied. The effects of atomic screening and finite nuclear size have not been included. Using the quoted value for the polarization measured in the pure Gamow-Teller transition in ${\mathrm{Co}}^{60}$ yields ${C_A}^{\prime }=(0.7\mathrm{} \mathrm{to} 1.45)C_A$.