The Tecnai G2 F30 S-TWIN microscope is a 300 kV transmission electron microscope with a field emission gun (FEG). It is a multi-purpose and multi-user tool with ease in operation, for the field of nanomaterials research, comprising TEM, EFTEM & STEM as operating modes. The instrument provides an optimal balance between contrast at high inclination angles of the specimen introduced for analysis and an excellent resolution. With a dedicated tomography holder, even larger tilt angles are possible, which allow high-resolution tomography on the system. With the field emission gun (FEG), fine analysis techniques (such as STEM with HAADF detector) can be easily performed. In addition, the flexibility offered by the 300 kV acceleration voltage allows users to select the optimal operating conditions for each experiment, exceeding the highest resolution that can be achieved with dedicated systems with maximum acceleration voltages of 200 kV.
The composition of the microscope
- Microscope column: contains the field emission gun with a Schottky field emitter and
vacuum system that allows the isolation of the gun from the rest of the column (the column
can be aired while the gun is in high vacuum), two condenser lenses, S-TWIN objective
lenses with a goniometer with computerized movements, motorized on 5 axes and eucentric
(allows the sample to be tilted without moving the target area on the captured image, whether
the area of interest is in the center or outside the specimen), diffraction lenses, intermediary
lenses, two projector lenses and ports for CCD cameras, power filters and other accessories.
Below the column is the projection camera with two viewing windows, a large fluorescent
screen (160 mm diameter), a small fluorescent screen for critical focusing using a high quality
binocular optical microscope with 12x magnification and a beam closing mechanism. - STEM: : The incorporation of STEM increases the versatility of the instrument without
compromising other modes of operation (TEM, EFTEM, analytical). In all modes of
operation, the samples are located in the eucentric position. This is the optimal position for all
operating modes, making it possible to quickly switch between TEM and STEM operating
modes. The STEM option consists of hardware components (Bright Field/Dark Field and/or
High-Angle, Annular Dark Field detector – HAADF) and software (Image Scan Mode), and
can be retro-fitted if necessary. - X-ray analysis: The EDS package provides all the hardware and software required for EDS
qualitative and quantitative analysis as well as for the EDS spectral image. - EFTEM: The functions of the microscope can be extended by using an energy filter
positioned under the projection chamber. It allows for composition mapping, filtering at zero
energy losses and at non-zero losses, as well as spectroscopy. The software is integrated in the
main Graphical Interface Tecnai User Interface through which all the main functions of the
filter can be controlled. The spectrometer also contains the EELS module and the CCD
spectral image obtained with a second CCD camera that allows the capture of digital images
for non-EFTEM applications.
Technical characteristics
Optical electronics | |
TEM point resolution | 2 Å |
Extended resolution (TrueImage) | 1,6 Å |
Information limit | 1,4 Å |
TEM line resolution | 1,02 Å |
STEM HAADF resolution | 1,9 Å |
High voltage | 50 – 300 kV; can be software switched in steps (preset values of 50, 100, 150, 200, 250, 300 kV) or continuously, between 10 and 300 kV with a minimum step of 70V; switch in less than 1 min. |
High voltage stability | ≤ 1 ppm |
Illumination modes | Microprobe, nanoprobe, LM (Low Mag) |
Number of focus dimensions | 11 |
Minimum beam dimension | ≤ 3 Å for nanoprobe mode (STEM); 10 Å for microprobe mode (TEM, HR-TEM and TEM-LOW-DOSE); 85 Å for LM (Low Mag) mode |
Number of condenser lenses | 5 condenser lens system: cannon lens, C1, C2, mini-condenser and pre-field objective lens |
Number of C1 apertures (condenser 1) | 4 interchangeable: 2000, 70, 50 & 30 µm Pt |
Number of C2 apertures (condenser 2) | 4 interchangeable: 150, 100, 70 & 50 µm |
Number of objective apertures | 8 interchangeables: 100, 70, 60, 50, 40, 30, 20 & 10 µm
The objective apertures are found within the focal plane of the objective lenses. |
Number of selected area (SA) apertures | 4 interchangeabla: 800, 200, 40 & 10 µm Pt |
Distance between the polar pieces of the objective lense | 5,4 mm |
Focal length | 2,3 mm |
Spherical aberration constant (Cs) | 1,2 mm |
Chromatic aberration constant (Cc) | 1,4 mm |
Minimum focus step | 1,8 nm |
TEM magnification range | 60x – 1 000 000x |
STEM magnification range | 150x – 230 000 000x |
Camera length (mm) | 80 – 4 500 |
Diffraction convergence angle | 100 mRad |
Diffraction grating | ± 12° |
Electron source | |
Type | Schottky Field emitter with zirconium oxide tip |
Beam current | > 100 nA (up to 150 nA) |
Beam current for a beam dimension of 1 nm | ≥ 0,6 nA (up to 1nA) |
Energy spread | ≤ 0,8 eV (up to ≤ 0,7 eV) |
Spot drift | < 1 nm/min |
Specimen handling | |
Specimen positioning | With high-precision CompuStage eucentric goniometer Automatic positioning of the specimen in the eucentric position immediately after loading |
Specimen tilt to the alpha angle | ± 40° for any combination of X, Y, Z, α, β with double-tilt object holder and 3 mm diameter TEM grid;
± 80°for any combination of X, Y, Z, α, β with tomographic slide and 3 mm diameter TEM grid |
X/Y movement | ± 1 mm |
Z movement | ± 0,375 mm |
Specimen recall reproducibility | ≤ 0.3 μm (after movement of 300 μm in X and Y) ≤ 0.1 μm (alpha angle tilt) |
Number of memorized positions | Infinite, including optical settings (intensity, magnification, spot dimension) |
Sample change time | <1 minute, software programmable pump time for sample introduction hatch, without interruption of the high voltage or filament heating |
STPS | Smart Tracking Position Tracking – interfaţă grafică pentru vizualizarea traseelor pe care s-a efectuat căutarea pe probă, inclusiv a poziţiilor fixe memorate |
Advanced repositioning | Repositioning the stage through a comment |
Specimen drift | ≤ 0,5 nm/min. |
Modes | |
STEM mode | With high-resolution, retractable HAADF detector installed above the projection camera Fast switching between TEM and STEM modes due to positioning of the sample in the eucentric position of the protractor in any of the operating modes STEM acquisition can be done simultaneously with CCD camera image acquisition and EDS acquisition |
EDS spectrometer | Detector with retraction and return to the motorized measuring position EDX detector resolution: ≤ 132 eVEDX Detector Window: SUTW (Super Ultra Twin Window) EDX solid detector angle: 0.13 str Signal to noise ratio: > 18,000:1 False peak rate: < 1% High-performance specialized software |
EELS spectrometer | EELS spectrometer, 0.4 eV resolution; diameter of the inlet aperture of 3 mm, observed energy field of 1024 eV at 300 KV |
Additional tools
– Double-tilt holder (left-right and front-rear), high visibility and low induced
background noise
– STEM hardware system for FEG
– Image scanning mode
– HAADF detector for 300 kV
– EDAX Analyzer (DPP-II)
– Motorized retractable detector with super ultra thin window (r-TEM SUTW Detector Unit) for Tecnai 300 kV TWIN and S-TWIN
– EDX spectroscopy mode
– TrueImage Professional TEM AutoAdjust software
– Acquisition of focal series
– Reconstruction of focal series
– TEM AutoGun
– Gatan GIF2001 P for 300 kV
– Energy filter holder
– EFTEM EELS mode
– CCD camera support