Development of high energy-resolution soft-X-ray emission spectroscopy microscope

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A new grating for a grazing incidence flat-field spectrograph was designed from 400eV to 1200eV with a groove density of 2400 lines/mm. The grating has a two times larger energy dispersion than that of a commercial grating. A new spectrometer chamber was designed to used not only for the new grating but also for commercial gratings. As energy region of 60-1200 eV is accessible by using the new and commercial gratings.X-ray reflection mirrors were designed to improve X-ray intensity to go into the grating. The mirrors have elliptical curvatures. The material for the mirrors was tungsten of about 100 nm thickness, which was formed on a cleaved natural mica crystal. The length and the width of the mirror were 135 mm and about 10 mm, respectively. Two mirrors were put between the grating and the specimen. Spectral intensity was improved by four times compared with those obtained without the mirror. The effective collection angle 2.8x10^<-3>sr.The developed soft-X-ray spectrometer attached to a transmission electron microscope (TEM) of JEM-2000FX. Energy dispersions per CCD detector channel (13.5 μm) of this spectrometer are about 0.1eV for Si L-emission (〜100eV), 0.2eV for B K-emission (〜180eV) and 0.7eV for Cu L-emission (〜930 eV). Cu L-emission spectra were obtained with a probe current of 10 nA at an acquisition time of 20 min. A VLS grating with line density of 24001/mm was used. The spectra clearly showed four L-emission peaks of L_α(M_y(3d)→L_<III>(2p)), L_β(M_<IV>(3d)→L_<II>(2p)), L_1(M_I(3s)→L_<III>(2p)) and Lη(M_I(3s)→L_<II>(2p)).The density of states of boron nano-belts and bundles of carbon nanotubes were obtained by using the X-ray emission spectroscopy microscope.