Last month I addressed the phenomena of beam scatter in the environmental and low vacuum SEM. In that article I covered how beam scatter is affected by chamber pressure, working distance, and accelerating voltage. To briefly summarize, beam scatter becomes worse at higher chamber pressure, longer working distance, and lower accelerating voltages. As the beam scatters, electrons strike the sample some distance away from the primary beam and as a result, generate X-rays from unwanted areas of the sample. It is advantageous for the analyst to keep beam scatter to a minimum to reduce the generation of these X-ray signals. Under conditions of high chamber pressure, long working distance, and low accelerating voltage, it is possible for electrons from the beam to strike the sample on the order of a millimeter or more from the primary beam.