Field Emission Scanning Electron Microscope

Instrument specification

Thermo Scientfic Verios G4 UC High resolution field emission scanning electron microscope (FESEM) operates at a variety of voltages ranging from 2 – 30 kV. It has Schottky FEG electron gun having an adjustable probe current ranging between 0.8 nA – 100 nA. It has a magnification of over 1,000,000 x providing a high resolution of 0.6 nm. FESEM operates under a vacuum system that is entirely oil-free. Differential pumping on the electron column ensures tip operation at the ultra-high vacuum levels (10-10 mbar).

Technicalities

The Verios G4 UC features through-the-lens (TLD) SE and BSE detection specifically designed for high-resolution, imaging at both high and low kVs, as well as an Everhart-Thornley SE detector for conventional SE detection. The in-lens SE detector features a technique where the energy range of the detected secondary electrons can be selected. The sample stage can be rotated 360 o and tiled to – 60 o making the system very versatile. Scan rate for the system ranges from 50 ms all the way upto 50 s.

Key features

Theory of operation

A scanning electron microscope is a type of electron microscope that produces images of sample by scanning the surface of the sample with a focused beam of electrons. These electrons interact with atoms in the sample, producing various signals that contain information about the surface topology and composition of the sample. Electron beam upon impact with the surface emits, secondary electrons, back scattered electrons, characteristic X-rays and light. These captured by various detectors.

To learn more about the working principle of SEM, please visit, https://en.wikipedia.org/wiki/Scanning_electron_microscope

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