Asymmetry of bremsstrahlung from transversely polarized electrons

By using an electron-photon coincidence method the photon emission asymmetry in the elementary process of bremsstrahlung from transversely polarized electrons was measured. For an electron beam of 300 keV incident on a gold target the asymmetry for spin up and down of the primary beam was measured for fixed direc-tions of the outgoing electrons and photons as a function of the energy split. Asymmetries up to 30% were found. The measurements are a proper test for theories going beyond the first Born approximation.