5.1 Figure 1

 

Doubly differential cross-sections for bremsstrahlung in collisions of 223.2 MeV/amu U⁹⁰⁺ with N₂ (left), and Ar (right) at observation angles $\Theta=132^{o}$ and $\Theta=90^{o}$, respectively. The experimental data are compared to the Bethe-Heitler-Elwert model taking into account the Doppler broadening and the electron momentum distribution of the target atom (dotted line), and to the ``exact'' point-Coulomb field calculations (solid line).