Design of a varied-line-spacing plane grating monochromator at NSRL for surface physics experiments

Abstract

The optical design of a varied-line-spacing plane grating monochromator for surface physics experiments at NSRL is presented. The monochromator consists of a plane mirror and two interchangeable gratings with line densities of 400 l/mm and 1200 l/mm to cover the energy range 20-600 e V. The expected resolving power E/ΔE is about 10000 at 29 eV and 244 eV with entrance slit's width of 30 μm. The photon flux is above 5×1010 phs/sec/300mA for most of the photon energy covered. The grating groove density parameters are chosen by minimizing coma and spherical aberration.