| CPC H01J 37/1472 (2013.01) [H01J 37/05 (2013.01); H01J 2237/057 (2013.01); H01J 2237/1516 (2013.01); H01J 2237/26 (2013.01)] | 24 Claims |

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1. An electrode structure for guiding a beam of charged particles along a longitudinal path,
wherein the electrode structure has multipole electrode arrangements that are spaced apart from one another along the longitudinal path, the multipole electrode arrangements having DC voltage electrodes, the DC voltage electrodes being configured to generate static multipole fields centered around the longitudinal path in transverse planes oriented perpendicular to the longitudinal path,
wherein field strengths of the static multipole fields in the transverse planes each have a local minimum at a location of the path and increase as a distance from the location of the path increases,
wherein field directions of the static multipole fields vary periodically with a period length along the longitudinal path so that the charged particles propagating along the longitudinal path are subjected to an inhomogeneous alternating electric field due to their intrinsic movement and experience a transverse return force towards the longitudinal path on average over time, and
wherein the period length is less than 60 mm.
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