VG HB 501
The VG HB 501 is a dedicated Scanning Transmission Electron Microscope (STEM). It is NCEM’s first aberration-corrected instrument, operating at 100 kV and under ultra-high vacuum (with typical pressures in the specimen chamber in the mid 10e-9 mbar range. Combining the power of aberration correction and the low native energy spread of its cold field emission gun (FEG) allows for electron energy loss spectra to be recorded on the high-resolution Enfina parallel EELS detector at simultaneous energy and spatial resolutions of 0.4 eV and 1.0 A respectively. This instrument is therefore ideal for high-end, high-resolution, experiments aiming to probe locally the structural and electronic properties of materials at the angstrom level.
For instrument schedule and requirements: contact Quentin Ramasse.
| Specifications | |
| Accelerating voltage | 100 kV |
| Spherical aberration (corrected) | -0.03 mm |
| Chromatic aberration | 1.0 mm |
| Operating vacuum (specimen) | ~10e-9 mbar |
| Cold FEG | |
| Detectors |
| High-angle annular dark field |
| Medium-angle annular dark field |
| Bright field |
| Parallel EELS spectrometer (high resolution Enfina) |
| Resolution |
| Imaging: 1.0 A |
| Energy resolution: <0.4 eV |
 |
High-angle annular dark field imaging: “Z-contrast High resolution unprocessed HAADF image of a hydrogen-encapsulating type-I clathrate, KxSi46. The inset shows a crystallographic average of the same image obtained with the 2dx software package, with the theoretical ball-and-stick structure superimposed. By comparing quantitatively such images with sets of simulations it was possible to determine the site occupancy of guest K atoms in the structure and to relate this value to the observed H intake of the compound.
|
 |
EELS at high spatial resolution HAADF image of an icosahedral FePt particle (false colors): thanks to the small probe size, it is possible to probe precisely the chemical structure of samples at the atomic level, revealing here a small crystalline layer of iron oxide surrounding the outermost shell of the particle. |