A charged particle multi-beamlet system for exposing a target (11) using a plurality of beamlets. The system comprises a charged particle source (1) for generating a charged particle beam (20), a beamlet aperture array (4D) for defining groups of beamlets (23) from the generated beam, a beamlet blanker array (6) comprising an array of blankers for controllably blanking the beamlets (23), a beam stop array (8) for blanking beamlets (23) deflected by the blankers, the beam stop array (8) comprising an array of apertures, each beam stop aperture corresponding to one or more of the blankers, and an array of projection lens systems (10) for projecting beamlets on to the surface of the target. The system images the source (1) onto a plane at the beam stop array (8), at the effective lens plane of the projection lens systems (10), or between the beam stop array (8) and the effective lens plane of the projection lens systems (10), and the system images the beamlet aperture array (4D) onto the target (11).