Electron microscopy
NanoMEGAS and Its Systems
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        



Table 1175. NanoMEGAS and its systems.

NanoMEGAS Created in 2004 [1]
Reciprocal cell Can be reconstructed automatically and precisely (error 2-5%) [1]
Crystal cell parameters Can be evaluated automatically and precisely (error 2-5%) [1]
Beam size 50 nm or less [1]
Hardware DigiSTAR
Diffraction mode Selected Area Electron Diffraction (SAED), Nanobeam Electron Diffraction (NED), Pair Distribution Function(PDF)
Diffraction intensity Quasi-kinematical integrated intensities [1]
Detectable reflections Enables the collection of higher-order reflections, which are more sensitive than lower-order reflections to small changes in lattice parameters [2]
Rotation frequency ~100 Hz [2]
ASTAR Automatic crystallographic indexing and orientation/phase mapping tool for TEM
The electron beam is scanned in combination with beam precession through the sample area of interest [1]
Beam scanning is done by the NanoMEGAS DigiSTAR precession unit without using an inbuilt STEM mode [1]

A number of ED (Electron Diffraction) patterns from several sample locations can be acquired at high speed [1]

Local crystal orientation(s) are obtained by comparing all individually obtained ED spot patterns via cross-correlation matching techniques with pre-calculated ED templates [1]

ADT3D software module

Allows users to index every reflection and to extract intensities useable for structure analysis procedure [1]

EDS and EELS measurements Beam Precession reduces channeling effects in EELS and EDS spectroscopy measurements














[1] Advanced Tools For Electron Diffraction.
[2] A. D. Darbal, R. D. Narayan, C. Vartuli, G. Lian, R. Graham, F. Shaapur, S. Nicolopoulos and J. K. Weiss, Automated High Precision Strain Measurement Using Nanobeam Diffraction Coupled with Precession, Microsc. Microanal. 19 (Suppl 2), 2013.