Magnetic Trap Devices For Elimination Of High Voltage Breakdown In Electron Beam Welding Equipment

TWI Industrial Member Report Summary 48/1977

By A Sanderson

Background

High voltage breakdown of electron beam guns due to particle streams generated in the weld capillary is generally known to be an inherent weakness of the electron beam process. Conventional techniques for reducing gun discharging can lead to excessive beam aberration, unacceptable beam spot movement and difficulties of column alignment.

New double and triple magnetic trap devices are described which minimise beam spot movement without introducing excessive beam aberration. In particular the triple deflection system has been shown to eliminate gun dischargeing for gassy and volatile materials up to high power levels. In addition this device is easy to set up and potentially applicable to a wide range of equipment.