A 64-ANGSTROM NE-LIKE GE X-RAY LASER RESONANTLY PHOTOPUMPED BY LY-ALPHA MG RADIATION

A new laboratory X-ray laser is proposed which lases between single el ectron holes involving several 2sBAR-->2pBAR transitions between 64 an d 89 angstrom in neon-like germanium and which is photo-pumped by a 2p -->1s emission line in hydrogen-like magnesium. The bar over the 2s an d 2p states represents a single electron hole in an otherwise closed L shell configuration. The lasing occurs with quantum efficiencies as h igh as 13% on these inner shell transitions. Lasing is also enhanced o n several 3p-->3s transitions in Ne-like Ge which would be expected to lase from collisional excitations and recombination processes, theref ore it should be much easier to observe the photo-pumping process on t hese longer wavelength transitions as it will increase an already fini te exponential pin. Calculations of the gain of these transitions in s teady-state equilibrium plasmas are presented.