Apreo LoVac scanning electron microscope (FEG-SEM)

a field-emission gun SEM with nm resolution for the study of the morhology, elemental composition, and grain orientation in solid materials.

Main features:

- accelerating voltage between 200 V and 30 kV (with beam deceleration even 20 eV landing energy available), making possible high-contrast imaging at low interaction energies; 
- can be operated under both high and low vacuum conditions (vacuum-sensitive and non-conducting materials can be studied); resolution in high vacuum 0.8 nm, in low vacuum 1.2 nm;
- imaging with secondary electrons (3 SE detectors), back-scattered electrons (2 BSE detectors); and in transmission (STEM) mode;
- energy-dispersive X-ray (EDS) detector for the quantitative analysis of elemental compositions and elemental mapping;
- electorn back-scattered detector (EBSD) for the analysis of grain orientations in crystalline materials.

Accelerating voltage:

- variable in the 200 V – 30 kV range, landing voltage in the 20 V – 30 kV range.

Gun:

-Schottky field-emission source, with a probe current of 400 nA at 5 kV accelerating voltage.

Vacuum system:

- oil-free, high-vacuum mode 10^-4 Pa; low-vacuum mode 500 Pa.

Resolution:

- at 15 kV accelerating voltage and in high vacuum 1.0 nm; in low vacuum 1.2 nm.
- at 1 kV accelerating voltage without beam deceleration, in high vacuum 1.3 nm.

Electron optics and scanning electronics:

- external magnetic field-free objective lens; scanning with variable pixel density, drift compensation.

Specimen stage and holders:

- Specimen stage with x-y translation 110×110 mm, z translation 65 mm, tiltable and rotatable, motorized on all five axes, eucentric and compucentric; 18 position SEM specimen holder; horizontal, 6 position STEM specimen holder.

Everhart-Thornley SE detector; SE detector for low vacuum; ”in-lens” SE and BSE detectors; motorized, retractable, solid state BSE detector; retractable, annular, multisegment STEM detector for both bright- and dark-field imaging.

EDS system:

- Be and heavier elements detectable;
- Si drift detector operated without liquid nitrogen, 30 mm2 active surface;
- 35˚ take-off angle; 129 eV resolution (at the Mn Kα peak, at 100000 counts/sec mellett);
- drift correction for elemental mapping.

Electron backscattered diffraction, EBSD:

- vertically adjustable, high-speed EBSD detector;
- simultaneous EBSD and EDX data collection,
- 1000 point/sec speed;
- automatic calibration;
- phase analysis (the system includes a crystallographic database);
- indexing and determination of crystallographic orientation;
- grain boundary analysis,
- calculation of orientation frequency distribution,
- display of 3D pole map.