Atomic collision processes at relativistic energies

The increasing opportunities to do atomic physics at high energy accelerators bring a whole new field of atomic collisions. For example, during the collision of two bare relativistic heavy ions an electron-positron pair can be created with the electron materializing directly bound to an ion. The authors made the first experimental observation of this process at the Lawrence Berkeley Laboratory's Bevalac using U92+ and La57+ beams with energies ranging from 405 MeV/u to 1400 MeV/u. They found that, unlike the other known capture mechanisms (radiative electron capture and non-radiative electron capture), the cross section of capture from pair production increases with increasing the collision energy