High-luminosity focusing x-ray spectrograph for laser plasma investigations

A Johann-type focusing x-ray spectrograph with a concave mica crystal was constructed. When a laser plasma was used as an x-ray source, this spectrograph was found to be characterized by a high luminosity, good spectral resolution, and minimum influence on the source size on the resolution. When the radiation flux density generated by a neodymium laser was (5–7)X10¹² W/cm² on the target surface, a single laser flash was sufficient to record the hydrogen- and helium-like spectra of the Na, Mg, and Al ions. The high luminosity of the instrument made it possible to record the Mg XI and XII spectra with a spatial resolution of 120 μ, and to determine the dependences of the electron temperatures T_e and electron density N_e on the distance from the target.