Patent ID: 7525103

Claim:
An apparatus for improving uniformity of a ribbon beam having a plurality of beamlets, the apparatus comprising: a first corrector-bar assembly having a first set of magnetic core members and a first plurality of coils distributed along the first set of magnetic core members; and a second corrector-bar assembly having a second set of magnetic core members and a second plurality of coils distributed along the second set of magnetic core members, wherein the second corrector-bar assembly is located at a predetermined distance from the first corrector-bar assembly; wherein each of the first plurality of coils is individually excited to deflect at least one beamlet in the ribbon beam, thereby causing the plurality of beamlets to arrive at the second corrector-bar assembly in a desired spatial spread, and wherein each of the second plurality of coils is individually excited to further deflect one or more beamlets in the ribbon beam, thereby causing the plurality of beamlets to exit the second corrector-bar assembly at desired angles.