AN X-RAY LASER OPERATING ON 2S-2P TRANSITIONS OF A NE-LIKE ION

A new x-ray laser using Ne-like ions and exploiting certain features o f the fine structure of these ions is discussed theoretically. The pum ping is a resonant photoexcitation, which sends a 2S electron from the ground state into 3P, 4P, etc., excited sublevels. As a result, a 2S hole forms in the L shell. The filling of this hole by 2P electrons ma y result in lasing. Calculations of the gain coefficients on 2S-2P tra nsitions in Ne-like Ge as a function of the pump intensity and the den sity of the active medium are reported for the particular example of t he Mg-Ge resonant pair.