Particle beam emitting assembly
AssigneeThe Welding Institute
InventorAllan Sanderson
Life of this patent
Estimating the term…
Abstract
A charged particle emitting assembly comprises an emitter member (5) for emitting charged particles of one polarity. A tubular shield electrode (6) circumferentially surrounds the emitter member and is held in use at the same polarity as the charged particles. A tubular accelerating electrode (7) is positioned substantially coaxially with the shield electrode (6) and is held in use at the opposite polarity to the shield electrode. The arrangement is such that charged particles from the emitter member (5) initially spread laterally outwardly and then are focused into a beam which passes through the tubular accelerating electrode (7).
Claims37
A charged particle emitting assembly comprising an emitter member for emitting charged particles of one polarity;
- a tubular shield electrode circumferentially surrounding the emitter member and held in use at the same polarity as the charged particles;
- and a tubular accelerating electrode positioned substantially coaxially with the shield electrode and held in use at the opposite polarity to the shield electrode, the arrangement being such that charged particles from the emitter member initially spread laterally outwardly and then are focused into a beam which passes through the tubular accelerating electrode.
A charged particle emitter comprising an emitter member mounted in an aperture of a support member to which it is electrically connected, the emitter member having a lower work function than the support member whereby at a working temperature, the emitter member emits charged particles from an exposed surface characterised in that the exposed surface of the emitter member is substantially flush with or set back from an outwardly facing surface of the support member surrounding the aperture.
A charged particle beam column assembly for mounting to an evacuated charged particle beam source chamber, the assembly having a sequence of controlled pressure chambers, each having inlet and outlet apertures through which a charged particle beam can pass and an evacuation port for connection to a pump to enable the pressure in the chamber to be controlled, whereby the pressure in successive chambers increases in use characterised in that an evacuation port is connected to a downstream chamber via a conduit which extends within the assembly past at least one upstream chamber.
Dependencies are inferred from the claim text.