Wideband multilayer gratings for soft X-ray emission spectroscopy in 2-4 keV

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*; Sano, Kazuo*

A novel multilayer mirror has been invented to uniformly enhance the reflectivity in a few keV energy range at a fixed angle of incidence. The structure of the multilayer consists of a BC/W bilayer with topmost layer of W deposited on a W/BC multilayer with a topmost layer of BC, thus the order is inverted. This multilayer mirror is based on the scheme that the lights in the short and long wavelength ranges are reflected in the bottom and top regions, respectively. It is applied to a multilayer grating (MLG) for the purpose of use in a flat-field spectrograph attached to a conventional electron microscope. The diffraction efficiency is evaluated at the angle of incidence of 88.65 in the energy region of 2-4 keV. It is revealed that the MLG is effective to uniformly enhance the diffraction efficiency.