JEOL has developed a remarkable class of wavelength-dispersive spectrometers (WDS) that efficiently and concurrently captures very low energy rays, or so-called “soft” X-Rays, using a variable space grating.
With their ultra-low energy and low concentration sensitivity, these new Soft X-Ray Emission Spectrometers (SXES) can detect Li even at low single-digit weight percent concentrations. They also have a high spectral resolution (0.3 eV), which allows the separation between the Nitrogen Kα and Titanium Lℓ lines to be resolved with only 1.78 eV.
Its ability to perform chemical state analysis is another, and possibly the most significant, feature.
When electrons produce X-Rays, the spectrometer detects differences between the valence band and conduction band electrons, enabling bonding and crystal structure in samples containing the same elements. For example, it distinguishes the highly ordered pyrolytic graphite from the entirely carbon-based diamond and amorphous C.
JEOL has added a new Soft X-Ray Emission Spectrometer (SXES-ER) version with a wider energy range. The SXES-ER has a spectral range of 100 eV to about 2300 eV. By utilizing the L, M, and N lines, users can gather heavy and transition metal elements in addition to light elements.
JEOL W/LaB6/FEG EPMA systems and JEOL FE-SEMs can use the SXES.
Li Detection: Peak Shape in Compounds
In metallic Li, one K-line is found. Li-compounds have the potential to form an additional satellite peak, contingent on the valence band's occupancy.
High Energy Resolution Spectral Mapping
Thanks to the SXES, Li-K emission can now be directly observed for the first time. Additionally, it can map the various chemical states that arise in Li batteries at different battery charge levels.
Two independent Li-K emission lines can be mapped. The degree of battery charge is correlated with the lower energy Li-K line intensity, and the amount of metallically linked Li is correlated with the higher energy Li-K line intensity.
Fast Parallel Detection
A newly constructed aberration-corrected grating system and a highly sensitive X-Ray CCD allow the SXES to simultaneously capture a spectrum over a broad energy range.
Chemical State Analysis
The SXES can perform chemical state analysis in the same way as XPS or EELS. Using the Fermi-edge of the Al-L emission of Al metal, the SXES was shown to have an energy resolution of 0.3 eV.
Key Features
SXES
- Al-L fermi edge with an extreme spectral resolution of 0.3 eV
- Because there are no moving parts, the stability and reproducibility are high
- Part of an integrated analytical system or as a stand-alone detector
- Simple spectral mapping
- Excellent detection of light elements (fit for Li)
- Ideal for light element chemical state analysis, which is crucial for battery research
- Excellent sensitivity; in steel, only a few 10 s of ppm B
- Energy range: 50 eV to 210 eV (even third- and second-order lines have a high resolution and P/B ratio).
SXES-ER
- Zr-M z 1.2 eV FWHM JS300N and Fe-L α 5.0 eV FWHM JS200N exhibit ultrahigh spectral resolution.
- Because there are no moving parts, the stability and reproducibility are high.
- Part of an integrated analytical system or as a stand-alone detector.
- Simple spectral mapping
- Excellent first-order light element detection (B-S).
- Enables first-order K lines (N-S), L lines (Ca-Mo), and M lines (Cd-Bi) to be detected.
- Trace element analysis of Be-N's chemical state.