Patent ID: 9202670
Filing Date: 2015-12-01
Classification: H01J

Abstract:
1. A method of investigating a wavefront of a charged-particle beam that is directed from a source through an illuminator so as to traverse a sample plane and land upon a detector, an output of the detector being used in combination with a mathematical reconstruction technique so as to calculate at least one of phase information and amplitude information for the wavefront at a pre-defined location along its path to the detector in which: said beam is caused to traverse a particle-optical lens system disposed between said sample plane and said detector; at a selected location in the path from said source to said detector, a modulator is used to locally produce a given modulation of the wavefront; in a series of measurement sessions, different such modulations are employed, and the associated detector outputs are collectively used in said mathematical reconstruction; wherein said selected location is disposed in an image space of said lens system.