SXES focuses on the emission of soft X-rays resulting from the relaxation of excited states in the material created by electron bombardment.  The sample is bombarded with a low-energy (< 5 keV) electron beam using an EPMA and the energies and intensities of the soft X-rays emitted due to valence-to-core transitions are detected by using a varied line spaced grating.  Because the core-level vacancies are filled by valence-orbital electrons, SXES spectra give information about the chemical bonding.

The SXES spectrometer consists of two varied line-space gratings and a back-illuminated CCD, which is cooled to -70 C with a Peltier cooling device.  The system enables parallel collection of X-rays with energies in the range from 50 eV to 210 eV, with high energy resolution (0.2 eV @ Al  L Fermi edge, 73 eV) and high sensitivity.  The spectrometer can detect soft X-rays of more than 70 elements. The capabilities of the system include both chemical bonding state analysis and mapping. Quantitative elemental analysis using a calibration curve can also be performed.