High performance slit-less spectrometer for soft x-ray emission spectroscopy

We have designed and constructed a new flat-field-type slit-less soft x-ray emission spectrometer that enables high detection efficiency and high energy resolution in the energy range of 250-1000 eV. The energy resolution is optimized in the C 1s and O 1s regions, where the maximum energy resolution of 2500 (E/Delta E) is expected using a focused beam whose spot size is 5 mu m full width at half maximum in the vertical direction. A distortion of the linear profile of the focused image on the charge-coupled device (CCD) detector is successfully removed by using a cylindrical grating. This enabled us to apply a super-resolution reconstruction technique to compensate for the lack of spatial resolution of the CCD detector.