X-ray emission studies in relativistic collisions of Li-like uranium ions with gaseous target

The X-ray spectra produced by K-shell ionization in collisions of Li-like (U89+) uranium ions at an energy of 397 MeV/u with gaseous N2 target have been measured. The very high level selectivity during such collision has been found. The effect allows us to measure undistorted two-photon energy distribution from a decay of the 1s2s1S0 state in He-like uranium.