JEOL has developed an unprecedented new type of wavelength dispersive spectrometer (WDS) that utilizes a variable space grating, allowing the efficient and parallel collection of very low energy-rays (so called “soft” X-rays). These new Soft X-ray Emission Spectrometers (SXES) boast not only high spectral resolution (0.3eV) which allows for the Nitrogen Kα and Titanium Lℓ line to be resolved with a separation of only 1.78eV, 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 vs. amorphous C, all of which are made only of carbon.
JEOL has also added another version of the Soft X-ray Emission Spectrometer with an extended energy range (SXES-ER). The SXES-ER has a spectral range of 100eV to ~2300eV. This extended range allows collection of not only light elements, but transition metals and heavy element using L, M, and N lines.
The SXES is available for both JEOL FE-SEMs and JEOL W/LaB6/FEG EPMA systems.
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 spectrum over a wide energy range.
Chemical State Analysis
With the SXES, chemical state analysis is comparable to that of XPS or EELS. The SXES has an energy resolution of 0.3 eV, as demonstrated using the Fermi-edge of the Al-L emission of Al metal.