Acquiring Electron Images at Different Dwell Times

During the initial configuration and running of a preview electron image, the quality of the image may be somewhat poor at the default dwell time of 1 µs. Open the SEM Image Prefs panel to adjust the dwell time for each acquired image (blue cursor):

Changing the dwell will immediately update any preview that is running. Changing the dwell while an image is being acquired will not change the run-time dwell for that particular image. The table below shows typical results for 1 µs, 20 µs, and 100 µs dwells.

1 µs	20 µs	100 µs

Low dwells are recommended for setup and configuration work. Medium dwells may be adequate for most needs, depending on the statistics of your setup. Dwells higher than 100 µs are rarely needed for publication-quality images. The same principles apply to X-ray maps, although the dwell times for maps are commonly 1-3 orders of magnitude higher than for electron images.