Electrode structure for guiding a charged particle beam

A method of guiding a beam of charged particles along a longitudinal path, the method comprising:

• providing an electrode structure, 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;
• applying electrode voltages varying periodically along the longitudinal path to the DC voltage electrodes of the electrode arrangements so that charged particles propagating along the path are subjected to an oscillating inhomogeneous alternating electric field due to their intrinsic movement and experience a transverse return force towards the longitudinal path on average over time;
• feeding the charged particles along the longitudinal path into the electrode structure;
• and
• guiding the charged particles along the longitudinal path by the transverse return force.

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,
• wherein the electrode structure comprises electrode arrangements formed as a junction,
• wherein the electrode arrangements of the junction vary along the longitudinal path such that the longitudinal path can be split into a first partial path and a second partial path so that a first portion of the charged particles can be guided along the first partial path and a second portion of the charged particles can be guided along the second partial path,
• wherein the electrode arrangements of the junction each comprise three DC voltage electrodes that are arranged next to one another in a transverse direction and that have an inner electrode and two outer electrodes arranged at both sides of the inner electrode,
• wherein the inner and outer electrodes of individual electrode arrangements form three electrode rows extending along the longitudinal path, and
• wherein a transverse width of the inner electrodes increases along the longitudinal path.