ZEISS - LIBRA® 200 MC
Monochromated Field Emitter
Symmetric hexapole shaped fields in the electrostatic omega-type imaging element MC cancel 2nd order aberrations to yield minimum loss of brightness while producing a non-dispersive image of the source at the MC exit plane. As a result of no source image dispersion the monochromator also maintains the original spot size and unlike other dispersive designs is ideal for both MC-STEM and EELS spectroscopy under all operating conditions.
A large energy dispersion of 12 um/eV allows a range of selectable energy widths from ~0.7 eV (non-monochromated) down to 0.2 eV. Energy width is controlled by a set of mechanically or electro-optically driven apertures in the energy dispersive plane of the element. The electrostatic gun lens control and MC is persistently powered and continuously ready for use with no significant alignments required over a wide range of operating conditions.
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Features of LIBRA® 200 MC
LIBRA® 200MC offers a unique ease-of-use in a design that preserves both the angular and spatial distribution of the source to deliver an uncompromised monochromated spot for STEM mode and even energy illumination with improved temporal coherence in TEM mode with minimum loss of brightness. No longer limited by the energy spread of the source, the corrected Omega energy filter com-bines with the monochromator to yield high resolution EELS spectroscopy enabling access to chemistry, structure and electronic state infor-mation at less than 0.14 nm spatial resolution on the LIBRA® 200MC.
General Specifications
| Magnification | 8 to 1000000 x |
| Electron Microscope Type | TEM |
| Microscope Type | Electron |
Additional Specifications
Field Emitter: Schottky Field Emission System with integrated
OMEGA type monochromator
Accelerating voltage: 200 kV
Patented Koehler Illumination (parallel illumination):
*Three-lens condenser system for parallel and homogeneous
*TEM wide-field illumination independent of illumination
intensity
*Quick and easy switching between TEM and Spot mode by
push-button operation
*Reproducible and controlled illumination conditions in TEM
and Spot mode
Spatial resolution: Truly symmetrical objective lenses = two variants:
Point resolution: 0.24 nm (HR) 0.29 nm (HT)
Information Limit: 0.14 nm (HR) 0.19 nm (HT)
STEM resolution: 0.30 nm (HR) 0.45 nm (HT)
Energy resolution: = = 0.2 eV (Electrostatic OMEGA-shaped monochromator
design, dispersion-free spot formation, 12µm/eV dispersion
at filter slit plane, selectable slits with various widths)
Corrected OMEGA filter: Corrected for 2nd order and optimized for 3rd order aberrations
Alignment: Factory alignment
Dispersion: 1.85 µm/eV @ 200 kV
Distortion: 100mrad @ ?E = 10 eV slit width and 200 kV
> 150mrad @ ?E = 20 eV slit width and 200 kV
Non-Isochromaticity: < 0.5 eV over Ø 2.5 µm field-of-view on sample
Specimen stage: 5-axes fully eucentric goniometer
Tilt range:
a / ß ± 30° / ± 30° (HR pole piece)
a / ß ± 70° / ± 30° (HT pole piece)
both with double-tilt analytical holder
a ± 70° (HR pole piece)
with special tomography holder
Imaging system: Two 3 lens projector groups in front and behind the energy filter
Magnification
STEM: 2,000 x - 5,000,000 x
EELS: 20 x - 315 x (spectrum magnification)
Vacuum system:
Oil-free and differentially pumped vacuum system
Pre-vacuum scroll pump with buffer tank
TMP for viewing chamber, filter and airlock
IGPs for the column
2 IGPs for the emitter area
System control: WinTEMTM Graphical User Interface (GUI) based on Windows® XP,
operated by mouse, keyboard and dedicated control panels