Patent ID: 11942316
Assignee: SCIENTA OMICRON AB
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An aperture device attachable to a lens system, comprising a first end, and a second end at a distance from the first end, wherein the lens system is arranged to form a particle beam of charged particles, emitted from a sample surface of a particle emitting sample, which enter the lens system at the first end and to transport the charged particles to the second end,
wherein the aperture device comprises
an end surface which is to be arranged facing the sample surface,
at least one aperture arranged in the end surface for allowing at least a part of said particles to enter the lens system when the aperture device is attached to the lens system, and
a length axis which extends through the centre of said at least one aperture and is essentially perpendicular to the end surface,
characterized in that the aperture device further comprises
at least one gas outlet, which is arranged at a transverse distance perpendicular from the length axis, and is arranged to direct gas into a volume between the at least one aperture and the sample surface,
wherein the aperture device, within a distance of less than 10 times the transverse distance, perpendicular from the length axis, comprises gas flow constriction surface, to constrain the flow of gas from the volume between the at least one aperture and the sample surface and the gas flow constriction surface encircles the at least one gas outlet and the at least one aperture.