A target for precise Mّller polarimetry

In order to achieve better accuracy on the measurement of electron beam polarization employing ē - ē scattering, we have developed an improved polarized electron target. Using a pure iron foil saturated out-of-plane in a 4 T magnetic field one can reduce the systematical errors to the promille level. Measurement of the relative target polarization using polarized light and the Kerr effect allows to observe on-line the change in target polarization due to heating by the electron beam.