Design of a conical diffraction type plane holographic grating monochromator for use in the energy region of 1-4 keV

Koike, Masato; Namioka, Takeshi*

The high brightness soft X-ray sources have been playing an important role in frontier sciences and high technologies. Then it is often required to perform high-resolution spectroscopic measurements in the energy region of 1-10 keV by using a single instrument. Unfortunately, both the grating and the crystal spectrometer cannot meet the requirement satisfactorily, because of various problems they have in the efficiency, spectral resolution, and wavelength scanning range. To overcome these problems we have developed a conical diffraction type grating spectrometer for use in the 1-4 keV region. The spectrometer employs a toroidal mirror and a plane holographic grating to separate the imaging and dispersing functions. This spectrometer works both as monochromator and as spectrograph. In this paper, we describe details of the design and give the expected performance of the spectrometer for cases of practical interest in the use of soft X-ray synchrotron radiation and laboratory sources.