US Patent 11705252 Vacuum chamber arrangement for charged particle beam generator

The disclosure relates to an electron-optical module of an electron-optical apparatus. The electron-optical module comprises a vacuum chamber, a high voltage shielding arrangement located within the vacuum chamber, and an aperture array configured to form a plurality of beamlets from an electron beam and located within the high voltage shielding arrangement. Wherein the electron-optical module can be configured to be removable from the electron-optical apparatus.