The ADF detector window allows to adjust the size of the Bright Field (BF), Dark Field (DF) and Sector Detector (SD) as well as to modify the centering of all of them (Fig. 1). The sector detector consists in annulus made of 4 quadrants. It's inner size radius is larger or equal to the BF radius and it's outer size radius smaller or equal to the DF innner radius. The DF inner radius is also lager or equal to the BF radius.
The ADF imager allows to calculate at once 4 BF or DF images of increasing collection angles. The increment is selected by steps of 5, 10, 15, 20 or 25 mrad.