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Abstract

A particle beam apparatus has an optical axis (OA), an illuminating system (1, 2, 3, 4) for illuminating an object, which is positioned in an object plane (7), with a beam of charged particles and an objective (6) for imaging the illuminated object. The beam of charged particles is split at the object into a null beam and higher diffraction orders. The illuminating system is so configured that it generates an annularly-shaped illuminating aperture in a plane Fourier transformed to the object plane (7). A phase-shifting element (9) is mounted in a focal plane (15) of the objective (6) or in a plane conjugated thereto. The focal plane (15) faces away from the object plane (7). The phase-shifting element can be an einzel lens having two outer electrodes and one or several inner electrodes disposed therebetween when seen in the direction of the optical axis. The phase-shifting element can have an additional electrode at or near the optical axis.

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First Claim