A 33 angstrom laboratory X-ray laser

A new laboratory X-ray laser is proposed which lases between single electron holes involving several overline3s_{1}/{2} → overline3p_{3}/{2} transitions near 33 Å in nickel-like dysprosium and which is photo-pumped by a 2p _{3}/{2}→1s _{1}/{2} emission line in hydrogen-like silicon. The bar over the 3s and 3p states represents a single electron hole in an otherwise closed M shell configuration. The lasing occurs on these inner shell electrons. Calculations of the gain of these transitions in steady-state equilibrium plasmas are presented.