Imaging at very high resolution (1nm at 20keV and 2.5nm at 5keV) is possible with the Keck FE-SEM, a LEO 1550, which utilizes a Schottky Field Emitter. Its superb performance, particularly at low accelerating voltages (< 1keV), is aided by a Beam Booster. At 20keV and below, an additional 8keV is added to the chosen accelerating voltage. Boosting the beam to a higher energy means it is less sensitive to any stray electromagnetic fields as it travels down the column. At the pole piece the beam is then decelerated by 8keV, returning to its original chosen energy. The decelerating field of the Beam Booster also acts as an electrostatic lens, and its field is superimposed on the electromagnetic field of the objective lens. Together they form the light-optical equivalent of a lens triplet. This combination of lenses lowers the coefficients of chromatic and spherical aberration, particularly at low beam energies.
Its current user base is drawn from a wide variety of disciplines and includes chemists, physicists, biologists, material scientists, electrical engineers and others.