Measurement of the electron polarization in the β decay of 45Ca and 147Pm

In the present thesis measurements of the longitudinal degree of polarization of electrons from the β decays of 45Ca and 147Pm are described. In the measurement procedure used here the longitudinal polarization is transformed to a transverse one by means of a Wien filter and the degree of polarization thereafter analysed by Mott scattering. The problematics of an absolute calibration of the Mott polarimeter is circumvented by relative measurements. As reference serves the Gamov-Teller decay of 60Co the degree of polarization of which is considered as well known. Apparative uncertainties concerning the scattering geometry are removed by reversal fo the spin orientation in the Wien filter, turning of the Mott polarimeter around the beam axis, and correction by means of additional counters for the scattering events in forward direction. The results are in the studied energy range of 80-160 keV compatible with a degree of polarization P=-v/c. By this the results are in accordance with the statements of the (V-A) theory. Additionally especially in the case of 147Pm strong constraints of influences of the nulcear structure result. Details of these fundamentally possible nuclear structure effects and approaches to the theoretical description of the interaction are discussed. (orig.)