Bede Scientific Instruments Limited

Graham Vincent Fraser

John Leonard Wall

Neil Loxley

Mark Taylor

An X-ray generator comprises an evacuated and sealed X-ray tube, containing an electron gun and an X-ray target. An electron beam is produced by the electron gun in which the cathode is at negative high voltage, the electron gun consisting of a filament just inside the aperture of a Wehnelt grid which is biased negatively with respect to the filament. Two sets of beam deflection coils, are employed in two planes, mounted between the anode of the electron gun and the focussing lens to center the beam. Between the focussing lens and the target is an air-cored quadripole magnet which acts as a stigmator in that it turns the circular cross-section of the beam into an elongated one. This quadripole can be rotated about the tube axis so as to adjust the orientation of the line focus. The beam can be moved about on the target surface by controlling the currents in the four coils of the quadripole.

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Darlington, United Kingdom

Graham Vincent Fraser