Patent ID: 6194730
Filing Date: 2001-02-27
Classification: H01J

Abstract:
Electrostatic lens for focusing the beams of charged particles, more particularly of ions, which have at least two electrodes forming an electric conductor with a ring-shaped cross-section, the inner edge of which is essentially circular, each electrode being connected to a power supply being connectable to an electric potential and being fastened on a holding device, characterized in that:at least one of the electrodes comprises sector areas succeeding one another along the periphery of the electrode, and,each sector area covering one predetermined angle area of the periphery,the sector areas being electrically connected to one another,the sector areas being linked to the holding device via at least one adjusting element per sector areas andthe position of said sector areas being adjustable independent of the other sector areas by means of the at least one adjusting element during operation of the electrostatic lens.