Plane Polarization of 8.5 MeV Bremsstrahlung

Abstract

The polarization of bremsstrahlung produced by 8.5 MeV electrons incident on thin Al, Ag, Au and U targets in a betatron was studied with D 2 O-loaded nuclear emulsions. The Polarization was measured at the characteristic emission angle \(\varTheta{=}mc^{2}/E_{0}\) by observing the azimuthal angular distribution of photoprotons from deuterons. The results show different energy dependence of polarization for different elements. For low Z targets the polarization is positive and large in the lower energy part of bremsstrahlung spectrum, in qualitative agreement with the theoretical calculations. For high Z targets the polarization is negative in the higher energy range and positive in the lower energy range. This reversal of the sign of polarization occurs at much lower energies than those expected from the theory.