training for advanced research


Glossary terms about Charging

A build-up of electrons from the primary beam on the surface of non-conducting samples. The built-up charge can cause deflection of the primary beam, or discharge, which causes instability in SE images.

12 pages mention Charging

Acceleration voltage vs. specimen type
With a higher accelerating voltage the electron beam penetration is greater and the interaction volume is larger. 
Generating an image
This coating is applied for two main reasons: (1) Non-conductive specimens are often coated to reduce surface charging that can block the path of SE and cause distortion of signal level and image form; and (2) Low atomic number (Z) specimens (e. 
High vacuum mode and pump system
In this mode, a small amount of air is leaked into the chamber, where it ionises and reduces surface charging of insulating materials. 
Introduction - aims and learning outcomes
Risk assessment example: transport and analysis of a SEM sample
Risk assessment example: using a SEM
Saturating the filament
SEM challenge
Troubleshooting: edge effect, charging, sample damage
charging is produced by build-up of electrons in the sample and their uncontrolled discharge, and can produce unwanted artefacts, particularly in secondary electron images. 
Variable Pressure or Low Vacuum scanning electron microscopy (LVSEM)
This type of machine is basically like a conventional SEM but has the advantage in low vacuum (LV) mode that the pressure can be adjusted in the sample chamber until the artefact of "electron charging" is removed from images. 
What is resolution?