Transmission charged particle microscope with adjustable beam energy spread

Abstract

A method of using a Transmission Charged Particle Microscope comprising: A specimen holder, for holding a specimen; A source, for producing a beam of charged particles; An illuminator, for directing said beam along an optical axis so as to irradiate the specimen, the illuminator comprising: a monochromator, which is configured to produce an output beam with a given energy spread ΔE0; and a condenser lens assembly; An imaging system, for receiving a flux of charged particles transmitted through the specimen and directing it onto a sensing device; A controller, for controlling at least some operational aspects of the microscope, comprising the following steps: In a first use session, selecting at least one of: (a) an excitation of a first lens of said condenser lens assembly; (b) a width of a condenser aperture downstream of said first lens, so as to produce a first width W1—and associated first energy spread ΔE1—of an emerging beam exiting said aperture; In a second use session, selecting at least one of said parameters (a) and (b) so as to produce a second, different width W2—and associated second, different energy spread ΔE2—of said emerging beam.

Dependencies are inferred from the claim text.