NanoMEGAS was formed in 2004 by a team of scientists and experts in the field of electron crystallography and catalysis. They have created advanced electron diffraction tools dedicated to help TEM and X-ray users to solve unknown nanocrystal structures.
Introduction
Spinning Star
NanoMEGAS unique precession inteface SPINNING STAR can be adapted to any TEM ( old or brand new from 100-400 kv ) . By precessing incident beam at a constant angle around a zone axis in combination with a similar precession (descan) of the ED pattern below the specimen, the equivalent mechanism of the precession of the specimen is obtained.
SPINNING STAR takes control of TEM coils in order that scanning and de-scanning of the beam are exactly compensated for any spot size and any TEM ( even without STEM presence ) and in order that ED pattern remain stationary during precession.When precession interface is switched on, is fully independent from working mode of the microscope. ;when precession is switched off, the system is fully disconnected from TEM. With precession electron diffraction kinematically forbidden reflections and multiple scatterings are greatly reduced, making space group identification easier. and also reduces sensitivity of ED intensities to crystal thickness, misorientation effects and Ewald sphere curvature.
Using precession in a ED pattern results to huge extension of visible reflections at very high angles (diffraction order up to 0.05 nm) and an important redistribution of electron diffraction intensities due to the practical elimination of dynamical diffraction/multiple diffraction contributions.
- SPINNING STAR can easily be retrofitted to any (old or new) 100- 400 kV TEM
- Precession is possible for any beam size 300 - 10 nm ( or less )
- Precession is possible for parallel or convergent beam
- SPINNING STAR may ENHANCE OR UPGRADE capabilities of new or older TEMs
- Precession angle can vary continuously (0 - 70 mrad ) to reveal true crystal symmetry.
[ 1 1 1 ] cubic ( a = 11.982 A ) mayenite crystal Ca12Al14O33
electron diffraction reflections turn from dynamical to kinematical by continuously increasing precession angle from 0º to 3º with “spinning star” precession unit at TEM
Digistar
ASTAR
ASTAR - Automatic phase and orientation mapping for TEM
- ASTAR can easily be retrofitted to any (old or new) 100- 400 kV TEM
- TEM based technique similar to EBSD for SEM (with much higher resolution details)
- Perform detailed orientation maps (Orientation resol < 1º , < 5 nm step size) for metals, ceramics , semiconductors and any type of diffracting material, any crystal symmetry, no sample preparation
- Perform detailed crystal phase maps (resolution < 5 nm -TEM FEG , < 25 nm - LaB6 TEM)
- Ultra-fast data acquisition (< 5 min ) (e.g. 5x 5 microns, 500 x 500 points) with CCD camera
- Scanning in combination with precession for accurate orientation and phase maps
- Generation of simulated ED patterns (templates) for all possible crystal symmetries and comparison with experimental ED patterns via cross – correlation techniques. to retrieve accurate phase and orientation maps (any crystal symmetry)