Environmental Scanning Electron Microscopy
The Environmental Scanning Electron Microscope is utilized to view biological and nonconductive samples. Since the ESEM uses a partial pressure of water vapor (10 Torr vacuum) to image, non-conductive samples do not build up a negative charge which would render any normal SEM useless.

![Environmental Scanning Electron Microscope [Photo by David A. Lange, UIUC]](http://publish.illinois.edu/concretemicroscopylibrary/files/2014/04/envsem.jpg)