32.8-nm X-ray laser produced in a krypton cluster jet

We have interpreted the well-known experimental quantum yield data for a 32.8-nm X-ray laser operating at the 3d⁹4d (J = 0) – 3d⁹4p (J = 1) transition of Kr⁸⁺ with the use of gaseous krypton or a krypton cluster jet. Proceeding from our model we propose a novel scheme for the 32.8-nm laser produced in a krypton cluster jet. The quantum yield is shown to saturate for a plasma length of ~300 μm, a krypton ion density n_Kr ~ (4 Ndash; 9) × 10¹⁹ cm^-3, and an electron temperature Te ~ 5000 eV. In this case, the energy conversion coefficient amounts to ~5 × 10^-3 of the pump pulse energy. We propose the experimental setup for producing a highefficiency subpicosecond X-ray laser in a krypton cluster jet.