Grazing-incidence Monk-Gillieson monochromator based on surface normal rotation of a varied-line-spacing grating

Koike, Masato; Namioka, Takeshi*

A plane grating monochromator having a simple wavelength scanning method requiring only a rotation of a grating about its normal was analyzed on the basis of the light path function. This scanning method has been known as surface normal rotation (SNR). A varied line spacing (VLS) plane grating was assumed to be illuminated by a convergent beam generated by a spherical mirror. We gave the analytical expressions for the grating equation, focal conditions, direction of dispersion, slant angle and length of astigmatic image, and a method to optimize the groove parameters of the VLS grating. The results of this analysis and the expected resolving power were evaluated by means of ray tracing for two model systems.