Scanning electron microscope electron beam source SEM 20

Electron source for SEM and Auger experiments with spot size better than 20 nm at 25 kV beam voltage/0.5 nA beam current, at 25 mm working distance. 1 - 25 keV thermal field emission electron source (Schottky emitter), maximum beam current >100 nA. Electrostatic focusing column with double lens system, beam alignment quadrupoles, beam blanking plates, and octopole for deflection and stigmation. Beam current is continuously adjustable by an electron-optically variable aperture. Internal beam current measurement facility by blanking onto a Faraday cup aperture connected to a B feedthrough. Pneumatically operated column isolation valve. Required source area vacuum <1 x 10-8 mbar. Pumping port NW 35 CF (2 " OD) at the side of the source chamber. Bakeable to 180 C. Mounting flange NW 63 CF (4 " OD).