Development of wide band soft X-ray grating spectrographs in 50-4000 eV and their application to electron microscopes

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*

For study of the electronic structure of materials including rechargeable lithium ion batteries and solar cells by means of soft X-ray emission spectroscopy based on electron microscopes (EMs), an objective flat-field grating spectrograph are designed to have an expanded detection range of 50-4000 eV with high resolution compared to commercially available wavelength or energy dispersive X-ray spectrometer. We have divided the energy range into four ranges, i.e., (1) 50-200 eV, (2) 155-350 eV, (3) 300-2200 eV, and (4) 2000-4000 eV, and designed the dedicated laminar holographic varied-line-spacing gratings for the respective ranges. All gratings can be accommodated by a single retractable spectrograph. Therefore, the energy range can be easily selected by exchanging the gratings. Furthermore, especially for the range of (4), a grating coated with a newly invented wide band multilayer is developed to cover the whole energy range at a constant angle of incidence.