A new multilayer-coated varied line-spaced grating, JS4000, was fabricated and tested for extending the upper limit of a grating X-ray spectrometer for electron microscopy. This grating was designed for 2-3.8 keV at a grazing incidence angle of 1.35°. It was revealed that this new multilayer structure enables us to take soft-X-ray emission spectra continuously from 1.5 to 4.3 keV at the same optical setting. The full-width at half maximum of Te-L(α1,2) (3.8 keV) emission peak was 27 eV. This spectrometer was applied to indium tin oxide particles and clearly resolved Sn-L(α) (3444 eV) and In-L(β1) (3487 eV) peaks, which could not be resolved by a widely used energy-dispersive X-ray spectrometer.
Keywords: indium tin oxide; multilayer coated grating; soft-X-ray emission spectroscopy; wavelength-dispersive spectroscopy.