Energy filter for charged particle beam apparatus
AssigneeU.S. Philips Corporation
InventorHarald Rose
Life of this patent
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Abstract
An energy selecting filter comprising a structure of four hemispheres to be transpassed successively by a beam of charged particles to be filtered. The structure is symmetrically with respect to a plane of symmetry in which the energy selecting element, such as slit or a knife-edge is introduced. In a charged particle beam apparatus such as a high resolution electron microscope the energy spread introduced by a source can adjustable be reduced to below for example 0,1 eV without introducing any beam deviation at the cost of only a small lengthening of the apparatus.
Claims13
Energy filter for monochromizing a charged particle beam in a charged particle beam apparatus characterized in that the filter comprises four basically hemispherically shaped condenser structures being arranged symmetrically on both sides of a plane of symmetry within the filter, each condenser comprising an outer hemispherical electrode and an inner hemispherical electrode to be connected to different potentials respectively.
Dependencies are inferred from the claim text.