X rays from radiative electron capture into continuum states in relativistic heavy-ion collisions

Continuum x rays originated from radiative electron capture into continuum states (RECC) of relativistic Ne10+ ions have been observed. It has been found that the intensities of x rays decrease as their energy increases and the observed spectra show a clear edge which corresponds to the maximum energy transferred to free electrons under energetic projectile-ion collisions. The edge becomes dramatically sharp as the incident projectile energy decreases from 290 to 75 MeV/amu, indicating that the cross sections for RECC sharply increase at low projectile energies, which is in agreement with the theoretical expectation. copyright 1997 The American Physical Society