Abstract:
A magnetic lens system, in particular for an electron microscope, comprising two thin small disc magnets, provided with small openings and magnetized axially in opposite directions, which are united straight into an electron-optic achromatic as well as rotation-free and distortionfree system that forms lens fields, at a distance that is practically equal to the diameter of the small openings.
Abstract:
According to one aspect of the invention for which protection is sought, there is provided an electron beam generator (100, 200) comprising: an electron source (104, 204) for generating a beam (120, 220) of electrons from an emission site of the source; means for accelerating the electrons; and focussing means for focussing the electrons onto a surface of a sample provided in an image plane, wherein the electron beam is arranged to pass through a plurality of apertures between the source and the image plane, each aperture having a diameter greater than that of the electron beam at the point at which the beam passes through the aperture, the generator being operable to image directly electrons from the emission site onto the image plane, the focussing means comprising a microscale lens (150, 250) comprising a lens element arranged to generate a magnetic field thereby to focus the electron beam onto the image plane, the lens element having a lens aperture therethrough through which in use electrons to be focussed are passed.
Abstract:
A fine-adjustable charged particle lens (10) comprises a magnetic circuit assembly (20) including permanent magnets (21) and a yoke body (25), surrounding a beam passage (11) extending along the longitudinal axis (cx). The permanent magnet is arranged between an inner yoke component (250) and an outer yoke component (251) so as to form a magnetic circuit having at least two gaps (290, 291), generating a magnetic field (61) reaching inwards into the beam passage, into which a sleeve insert (50) having electrostatic electrodes can be inserted, which may also generate an electric field (65) spatially overlapping said magnetic field. An electromagnetic adjustment coil (31) is located between the inner and outer yoke shell (250, 251). This electromagnetic adjustment coil (31) is driven by an adjustable supply current running primarily along a circumferential direction and modifies the magnetic flux in the magnetic circuit to cause a variation in the magnetic flux density in the gaps (290, 291).
Abstract:
Disclosed herein is an electron column using a magnetic lens layer. The electron column includes a magnetic lens layer for condensing an electron beam using permanent magnets. The magnetic lens layer includes a support plate, an aperture formed through the support plate, and permanent magnets arranged around the aperture and disposed on or inserted into the support plate.