Charged particle system, aperture array, charged particle tool and method of operating a charged particle system

A charged particle system for generating a charged particle multi beam along a charged particle multi beam path, the charged particle system comprising:

• a charged particle source;
• a condenser lens system;
• a beam-limit array;
• and
• an aperture array comprising a center and a pattern of apertures, wherein the pattern comprises a superposition of:
• a template pattern at a first rotation about the center and a first magnification, and
• the template pattern at a second rotation about the center and a second magnification.

A method of operating a charged particle system comprising an aperture array in which is defined an array of apertures, a beam-limit array arranged downbeam of the aperture array and in which is defined an array of beam-limit apertures, and a condenser lens system arranged between the aperture array and the beam-limit array, the method comprising:

• passing a charged particle beam through the apertures of the aperture array;
• operating the condenser lens system at two or more different rotation settings, each rotation setting defining a different beam path between the aperture array and the beam-limit array;
• and
• for each rotation setting, directing the charged particles from the aperture array through each of the beam-limit apertures of the beam-limit array.