Patent ID: 7842930

Claim:
A charged particle beam apparatus comprising: an objective lens adapted for focusing a primary charged particle beam on a specimen plane, so that charged particles are emitted from a specimen with a spatial distribution; and a charged particle detector assembly for detecting a spatial distribution of charged particles, the charged particle detector assembly comprising: a particle detector having at least one particle sensitive region for detecting at least a portion of the spatial distribution of charged particles and for generating a two-dimensional optical signal which correlates to the detected spatial distribution, wherein the particle sensitive region is an essentially singly connected region; an image conduit having an input coupled to the particle sensitive region of the particle detector for transmitting the two-dimensional optical signal to at least one optical detector; and a selecting means for selecting at least a portion of the two-dimensional optical signal, wherein the particle detector is arranged in front of the specimen with respect to a main propagation direction of the primary charged particle beam.