JEOL has developed an unprecedented new type of wavelength dispersive spectrometer (WDS) that utilizes a variable grating, allowing the efficient and parallel collection of very low energy-rays (so called “soft” X-rays). This new Soft X-ray Emission Spectrometer (SXES) boasts not only high spectral resolution (0.3eV) which allows for the Nitrogen Kα and Titanium Lℓ line to be separated, but also ultra-low energy, low-concentration sensitivity with the capability to detect Li even at low single digit weight percent concentration. An additional, and maybe its strongest asset, is its ability to do chemical state analysis. The spectrometer detects differences between conduction band and valence band electrons when they emit X-rays allowing the distinction between bonding and crystal structure in samples containing the same elements. An example would be differentiating highly ordered pyrolytic graphite vs. diamond, both of which are made only of carbon.
The SXES is available for both FE-SEM and EPMA.
Li Detection: Peak shape in compounds
In metallic Li, a single K-line is detected. In Li-compounds, and additional satellite peak can occur depending on the occupancy of the valence band.
High Energy Resolution Spectral Mapping
The SXES allows for direct observation of the Li-K emission for the first time. It is even capable of mapping the different chemical states within a Li-battery that result from different levels of battery charge. Two different Li-K emission lines can be mapped. The intensity of the lower energy Li-K line corresponds to the degree of charge in the battery and the higher energy Li-K line corresponds to the amount of metallically bonded Li.
Fast Parallel Detection
A newly developed aberration corrected grating system and a high sensitivity X-ray CCD allow the SXES to simultaneously collect a wide energy spectrum.
Chemical State Analysis
With the SXES, chemical state analysis is comparable to that of XPS or EELS. The SXES has an energy resolution of only 0.3 eV, as demonstrated using the Fermi-edge of the Al-L emission of Al metal.