High-luminosity x-ray spectrograph with a spherically bent crystal analyzer, designed for laser plasma diagnostics

A detailed theoretical analysis is made of the operation of an x-ray spectrograph with a spherical crystal analyzer in two types of task encountered in laser plasma research: measurement of the line profiles, and determination of the position of lines in a wide spectral range. It is shown that in the profile measurements the luminosity of a spectrograph with a spherical crystal can be more than an order of magnitude higher than the luminosity of a spectrograph with a cylindrical crystal. The results are reported of an experimental study in which a spectral resolution of λ/Δλ~2×10⁴ was achieved. The high luminosity of the spectrograph made it possible to record the expansion of a plasma jet at a distance of several millimeters from the target surface using just one laser flash of energy amounting to a few joules.