The invention relates to an
electron imaging apparatus (23) configured to be connected to an energy analyzer apparatus. The
electron imaging apparatus comprises a receiving aperture (22), a
control unit, and a field
generating unit (65). The receiving aperture is configured for receiving electrons from a
focal volume (200) which form an
electron beam (25). The
control unit is configured for providing a
control signal to the field
generating unit based on a desired height of the electron beam in an energy dispersive direction (y) of the energy analyzer apparatus at a proximal end (90) of the electron imaging apparatus and a desired
angular distribution (α p ) in the energy dispersive direction at the proximal end. The field
generating unit is configured for generating at least one electrostatic, magnetic, or electrostatic and
magnetic field based on the at least one
control signal such that the at least one electrostatic, magnetic, or electrostatic and
magnetic field is configured for exerting a force on the electrons of the electron beam in the energy dispersive direction such that a height of the electron beam in the energy dispersive direction at the proximal end corresponds to the desired height in the energy dispersive direction at the proximal end and an
angular distribution in the energy dispersive direction at the proximal end corresponds to the desired
angular distribution in the energy dispersive direction at the proximal end.