Multi-beam source

A multi-beam source for generating a plurality of beamlets of energetic electrically charged particles, the multi-beam source comprising:

• an illumination system;
• and
• a beam-forming system,
• wherein the illumination system is adapted to generate energetic electrically charged particles and to form said particles into a wide illuminating beam, and
• the beam forming system is configured to be illuminated by the illuminating beam emerging from the illumination system and is adapted to form a plurality of beamlets of energetic particles out of the beam, said beam forming system comprising:
• a beam-splitting means having a plurality of apertures transparent to the energetic particles of the particle beam to form the plurality of beamlets out of the beam, and
• an electrical zone device, said electrical zone device comprising a composite electrode being positioned along a two-dimensional plane oriented orthogonally to an optical axis of the electrical zone device and having lateral dimensions covering at least an area permeated by the particle beam, said composite electrode being composed of a plurality of substantially planar partial electrodes, said partial electrodes being arranged adjoining to each other according to a partitioning of the surface area of the electrical zone device and said partial electrodes being adapted to be applied different electrostatic potentials, the electrical zone device further comprising a plurality of openings transparent to the energetic particles of the particle beam.