Contrast formation in low vacuum and environmental SEMs

This project covers the whole image formation process in low vacuum or environmental Scanning Electron Microscopes(LV- or ESEM). It is essential to understand exactly the processes where secondary electrons create ions by collisions with gas molecules on their way to a biased detector. Additionally, more information on the behaviour of these ions (drift velocity, electron ion recombination) has to be gathered, which dominantly effects the contrast and thus the quality of images. Besides that experiments are preformed to get additional sample information by using mechanisms of image formation (charge contrast imaging).