| CPC H01J 37/1475 (2013.01) [H01J 37/09 (2013.01); H01J 37/141 (2013.01); H01J 37/153 (2013.01); H01J 37/28 (2013.01); H01J 2237/0453 (2013.01); H01J 2237/1532 (2013.01); H01J 2237/24564 (2013.01)] | 20 Claims |

|
1. A method, comprising:
generating a plurality of particle beams such that each particle beam passes through a multipole element, wherein each multipole element comprises a plurality of deflection elements arranged in a circumferential direction around a center of the multipole element, and each multipole element is either intact or defective;
focusing the particle beams in a predetermined plane;
determining excitations for the deflection elements of the multipole elements to influence the particle beams passing through the multipole elements, wherein the excitations for the deflection elements of each multipole element are determined such that focusing of each particle beam in the predetermined plane satisfies a predetermined criterion;
exciting the deflection elements of the multipole elements that are intact with the determined excitations;
modifying the determined excitations for the deflection elements of at least one multipole element of the multipole elements that are defective; and
exciting the deflection elements of the defective multipole element with the modified excitations,
wherein modifying the determined excitations comprises adding corrective excitations to the determined excitations, and the corrective excitations are the same for all deflection elements of the defective multipole element.
|