Patent ID: 8421027

Claim:
A charged particle analyser comprising: a first non-imaging electrostatic lens for receiving charged particles having divergent trajectories and for converting the said trajectories into substantially parallel trajectories; at least one planar filter, comprising one or more planar electrostatic filter grids, for receiving the charged particles having the said substantially parallel trajectories and for filtering the charged particles in accordance with their respective energies, wherein the filter is adapted to provide a decelerating field to prevent passage of charged particles having energies below a predetermined threshold; a second non-imaging electrostatic lens for receiving the energy filtered charged particles and selectively modifying their trajectories as a function of their energies; and a charged particle detector for receiving the charged particles in accordance with their selectively modified trajectories; wherein the charged particle analyser is positioned on a beam side of a specimen for the receipt of electrons scattered from the specimen as a result of interaction between the specimen and the electron beam.