X-ray emission from KrF laser-produced Al plasmas

Abstract
A high power (200 J, 50 ns) 249‐nm KrF laser has been focused onto solid Al targets in vacuum at a peak irradiance of 3×1013 W cm2. High‐temperature (>200 eV) plasmas are produced and x‐ray measurements show intense emission of the resonance spectra of Al XII and Al XIII in the wavelength range 0.6–0.8 nm. Absolute x‐ray intensity measurements indicate a maximum source brightness of 1.1×1017 erg cm2 s1 sterad1 in Δν/ν=103 (Al XII, 1 1S0–2 1P1, 0.776 nm) and a conversion efficiency from laser power to x‐ray power of 0.2% for 1.5 keV<hν<2.5 keV.