Two dogmas of charged particle optics
Abstract
Designs of charged particle optical systems are invariably based on two assumptions: (1) The existence of a reference trajectory and (2) midplane symmetry. The reference trajectory is taken to be the path of a charged particle with certain specified initial conditions. Conditions which break the continuity of the reference trajectory are misalignments of magnets, excess horizontal field in a bending magnet, and vertically bending field in a horizontally bending magnet. Even if midplane symmetry is violated in a magnetic system it is usually respected in each magnetic element. Violation of midplane symmetry in a bending magnet occur if the field is not symmetric about the magnetic midplane. Equations of motion have been worked out for the case where both the above mentioned conditions are violated. Solutions have been produced and incorporated into the first and secondorder formalism of charged particle optics.
 Publication:

Nuclear Instruments and Methods in Physics Research A
 Pub Date:
 August 1987
 DOI:
 10.1016/01689002(87)909247
 Bibcode:
 1987NIMPA.258..417C