An FEI Co. Tecnai G2 F20 S-Twin 200keV field-emission Scanning Transmission Electron Microscope (S/TEM) was installed in March 2005.
The super twin lens allows for 80° tilt and a point to point resolution of 0.16nm. A 1nm STEM probe allows for an imaging resolution of 0.19nm, and a high angle annular dark field detector (HAADF) allows for Z-contrast imaging in STEM mode at high resolution.
High resolution analytical capabilities are provided on the TF20 STEM. It is equipped with an EDAX energy dispersive x-ray spectrometer (EDS), a NanoMegas TOPSPIN Precession Electron Diffraction (PED) acquisition system and Thermo Fisher CETA 16M digital camera and an on-axis Bright-Field/Dark-Field STEM detector.
Instrument Specifications
Electron Source
- Flexible high tension (20, 40, 80, 120, 160, 200 kV and values in between)
- Schottky field emitter with high maximum beam current (> 100 nA)
- High probe current (0.5 nA or more in 1 nm probe)
- Small energy spread (0.7 eV or less)
- Spot drift < 1 nm/minute
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Specimen Stage
- Fully computer-controlled, eucentric side-entry, high stability CompuStage
- Maximized tilts for any X,Y,Z, α and β combination
- Choice of a variety of specimen holders
- X, Y movement ± 1 mm, Z movement ± 0.375 mm; specimen size 3 mm
- Specimen recall reproducibility: ≤ 0.3 μm (after movement of 300 μm in x and y) and ≤ 0.1 (α tilt)
- Drift ≤ 0.5 nm/minute with a standard holder attainable
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Imaging
- Coma-free alignment for high resolution objective lens centering
- Ranged, rotation-free magnification and diffraction series
- Magnification reproducible within ± 1.5%
- FEI CETA 16M CMOS Camera
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Software
Xplore3D™: FEI's intelligent tomography solution for TEM and STEM [CURRENTLY UNAVAILABLE]
TrueImage: FEI's patented focal series acquisition and reconstruction software package [CURRENTLY UNAVAILABLE]
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STEM
- Fully digital scan system
- Bright Field and Annular Dark-Field Mode
- High resolution STEM with HAADF detector
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S-Twin Objective Lens
- Information limit (nm) 0.14
- Extended resolution (nm) 0.16
- Minimum focus step (nm) 1.8
- TEM magnification range 25x - 1,030kx
- Camera length (mm) 30 - 4,500
- Maximum diffraction angle ±13°
- STEM HAADF resolution (nm) 0.19
- STEM magnification range 150 x - 230 Mx
- Maximum tilt angle with double-tilt holder ±40°
- Maximum tilt angle with tomography holder ±80°
- EDS solid angle (srad) 0.13
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Microanalysis
- Excellent EDS in-hole performance
(< 1% hole count)
- Low system background in EDS
(< 1% spurious peaks)
- High P/B ratio (Fiori number) > 4000
- EDAX Octane T Optima 30mm2 SDD EDS
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