PARTICLE OPTICAL APPARATUS

摘要

A particle optical apparatus including an aperture plate for shaping a particle beam before the particle beam enters a monochromator filter assembly. The aperture plate has at least one aperture and is adjustable with respect to the monochromator filter assembly, in normal operating conditions, so that the size of the aperture used to shape the particle beam can be varied, and therefore the beam current entering the filter assembly can be varied.