Charged Particle Generation With A Resonant Electrical Circuit

PCT No. PCT/GB93/02376 Sec. 371 Date Jul. 22, 1994 Sec. 102(e) Date Jul. 22, 1994 PCT Filed Nov. 19, 1993 PCT Pub. No. WO94/13006 PCT Pub. Date Jun. 9, 1994Apparatus for generating a stream of charged particles, for example for use in an electron beam welding device. The apparatus includes a charged particle source (5) such as a filament and a target (6). The charged particle source (5) is connected in series with a resonant electrical circuit and the target is connected in parallel with the circuit. The source and target (5,6) are relatively juxtaposed such that under working conditions, when the circuit is in resonance, electric current passing through the source (5) causes emission of first charged particles and the potential difference between the source (5) and the target (6) accelerates the first charged particles towards the target.