Spectral resolution of an X-ray spectrograph with a Jogansson spherical crystal

Calculations of characteristics of a spectrograph with a Jogansson spherica l crystal, whose analog was manufactured at the Kurchatov Institute Russian Research Center together with the Ecopulse Company (USA), are presented. I t is shown that the resolving power of such a spectrograph is three times h igher than that of a spectrometer with a Jogann spherical crystal and excee ds the resolution of a Jogansson spectrograph with a cylindrical crystal by a factor of 4Cos(2)Theta(B). Such calculations were performed for the firs t time. Argon spectra measured on a "plasma focus" setup, by using Jogann a nd Jogansson instruments, with cylindrical and spherical quartz crystals, r espectively, are presented.