Scanning transmission electron microscope offers outstanding mapping and analysis through electron energy loss spectroscopy or energy dispersive X-ray systems
Outstanding spatial resolution at the nanometre level can be achieved on chemical element mapping in the HD-2300 scanning transmission electron microscope from Hitachi High-Technologies. Mapping and analysis can be achieved using either electron energy loss spectroscopy (Eels) or energy dispersive X-ray (EDX) systems.
In addition to the ability to produce elemental maps at 2nm spatial resolution, the Eels system also has excellent energy resolution, which makes it possible to resolve adjacent peaks that cannot be adequately separated by EDX methods.
Eels is particularly sensitive for detecting trace quantities of transition elements, rare earth elements and low atomic number elements.
The Eels system has a high collection efficiency, not only giving high sensitivity, but also allowing data to be acquired rapidly.
Element maps can be acquired in as little as 40 seconds.
It is possible to switch from one element to another during a scan.
This allows precise boundaries between elements to be determined with nanometre resolution.
For EDX analysis, nanometre-level resolution for element mapping is achieved in the HD-2300 because a focused beam is used and the specimen is very thin.
This makes the interaction volume of the beam with the sample very small.
This is completely different from the SEM where the interaction volume can be as large as one micron.
EDX analysis in the HD-2300 offers improved sensitivity compared to conventional field emission transmission electron microscopes. This is because the solid angle for X-ray collection subtended at the EDX detection is 2.5 times greater than that in the TEM, which results in a corresponding increase in sensitivity.
For some applications where X-ray count rates are low, it may be necessary to collect EDX data over extended periods of time.
A dynamic drift compensation system is available for the HD-2300 which eliminates specimen drift which would otherwise result in reduced spatial resolution.
