A Cauchois-Johansson optical scheme is proposed, based on a specially desig
ned cylindrical quartz crystal. The corresponding x-ray spectrograph is man
ufactured, which provides high spectral resolution in transmission and refl
ection regimes and covers the wide energy range of 1.5-400 keV. The device
is calibrated with an x-ray tube and is suggested to be used in high-temper
ature plasma diagnostics. (C) 2001 American Institute of Physics.