High resolution X-ray emission spectra from picosecond laser irradiated Ge targets

Investigations of a high resolution X-ray emission spectrum in the range 0.66-0.75 nm obtained by irradiating a Germanium target with high-power p-polarized, 40 picosecond laser radiation at 532 nm wavelength was done. Spectra in the wavelength region of 2l-4l' and 2l-5l' L-shell transitions in F-like, Ne-like and Na-like germanium ions were recorded using the FSSR-21) spectrometer equipped with a spherically bent quartz crystal with a spectral resolution lambda/Delta lambda better than 5000. Spectral lines were compared with theoretical values obtained using the LANL, plasma kinetic code ATOMIC. Fair agreement between experimental and theoretical spectral lines has been observed, which allowed to measure enough high bulk electron temperature values of 560 eV and electron density of similar to 10(21) cm(-3) in Ge plasma irradiated by rather small commercial high repetition rate Nd:YAG laser system.