Study of electron bremsstrahlung in strong coulomb fields at the ESR storage ring

Electron bremsstrahlung has been investigated for collisions of 223.2 MeV/amu He-like uranium ions with N 2 and Ar gaseous targets. The doubly differential cross-sections for bremsstrahlung are compared to the predictions of relativistic first order Born calculations (Bethe-Heitler formula with Elwert correction factor) and to the calculations based on the exact wave-functions for electrons moving in the external point-Coulomb potential of the projectile. Whereas the "exact" IPA calculations give an improved agreement with experimental data, as compared to the Bethe-Heitler theory, in particular at the end-point region of the bremsstrahlung spectra, discrepancies still remain at lower photon energies. Typeset using REVT E X I. INTRODUCTION In relativistic atomic collisions the x-ray emission due to charge changing and excitation processes is accompanied by continuum radiation originating from electron bremsstrahlung. For low-Z systems the bremsstrahlung cross-sections are generally..