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Analytical Electron Microscope


The CM300FEG is a Transmission Electron Microscope equipped with spectroscopic detectors to allow chemical, elemental, and other analytical measurements to be performed at high spatial resolution. The CM300 operates between 100 keV and 300 keV electron beam energy, and uses a thermal (Schottky) field emission electron source to illuminate the sample. It can be used in full-field imaging mode as both a conventional TEM and a phase-contrast high resolution TEM for imaging the atomic scale lattice in many materials. It can also be used as a high resolution scanning transmission electron microscope (STEM), where a finely focused electron beam is scanned across the sample and an image is forming using one of several available electron or spectroscopic signals. This latter mode is particularly useful for performing elemental and chemical analyses of very small analytical volumes. The above capabilities are supplemented by a full suite of electron diffraction capabilities, including selected area electron diffraction (SAED) and convergent beam electron diffraction (CBED). These diffraction modalities allow the instrument to probe the crystallographic phase and microstructure of samples in addition to their structural and chemical properties.

The CM300 is also equipped with a post-column Gatan Imaging Energy Filter (GIF). The GIF can function as a conventional parallel electron energy-loss spectrometer (EELS) to record spectra of the energy losses experienced by the beam electrons as they scatter from sample atoms. It can also be used as an imaging energy filter to form energy-selected TEM images. This enables nanoscale elemental imaging methods such as energy filtered transmission electron microscopy (EFTEM). A 2k by 2k digital camera on the GIF allows the CM300 to acquire digital images.

Specifications / Capabilities:

* up to 300 keV electron beam energy
* Super-Twin Alpha objective lens pole piece
* +/- 80 degrees specimen tilt
* high-tilt tomographic and chemical/analytical experiments possible
* tomographic, low-background, heating, cryo, double tilt, double tilt plus rotate specimen holders
* electron energy-loss spectroscopy (EELS), with 1 eV energy resolution
* imaging energy filter
* energy filtered imaging (EFTEM)
* 2k CD digital image acquisition
* approximately 0.23 nm point-to-point spatial resolution in TEM mode
* approximately 1 nm STEM spatial resolution
* selected area electron diffraction modes
* convergent beam electron diffraction modes

Scientific Opportunities / Applications:

* tomographic and 3D elemental distributions
* sub-micrometer chemical heterogeneity
* nanoparticle imaging and chemical characterization
* magnetic nanostructure characterization
* semiconductor device measurements
* gate dielectric thickness metrology
* catalyst particle morphology, structure, and chemistry

Access Information:

Individual collaborative projects to address NIST measurement needs are possible when the work is consistent with the Surface and Microanalysis Science Division mission space. Contact Ian Anderson and John Henry Scott to discuss possible collaborations.

Associated Programs/Projects:

* 3D Chemical Imaging at the Nanoscale
* Compressive Sensing
* Bioimaging

Credit: NIST

Name: Ian Anderson
Phone: 301-975-8907
100 Bureau Drive, MS 8370
Gaithersburg, MD  20899-8370

Name: John Henry Scott
Phone: 301-975-4981