Comparison of monochromators with a bent parabolic mirror and a varied-spacing grating for the 2.0 GeV high-brilliance synchrotron radiation source (VSX).

A design study of monochromators for a 2.0 GeV electron/positron storage ring for high-brilliance synchrotron radiation in the vacuum ultraviolet (VUV) and the soft X-ray regions is described. Two types of VUV/soft X-ray grazing-incidence monochromators, one with a bent parabolic mirror and the other with a varied-spacing grating, are designed. Without any slope error, the expected resolving power of the former is much higher, but the latter is less affected by slope errors of the optical elements.