Electron beam basics - an introduction

Electron beam (EB) technology has existed for over a century, during which time it has developed from laboratory experiments to a powerful industrial tool in diverse applications.

This section gives an overview of the technology and puts TWI's EB technologies into context with other power beam processes and other EB applications.

Why electrons?

Electrons have a unique range of properties and characteristics that, in the view of many, make for a formidable power beam. The electron beam is powerful, controllable, precise and versatile; because of these qualities it finds a unique range of applications.

Electron beams are generated in a high vacuum environment, typically via a thermal cathode that is heated to more than 2000°C, and an accelerating potential of at least 10000 volts. This sounds a little exotic, and unlikely to be an everyday occurrence, but Electron Beams are used for more things than you might think.

They are used for:

TWI's involvement with EB technology began over forty years ago; it is just one element in the complex history of EB technology. Our involvement has mainly concentrated on welding processes, but activities such as electron gun design and prototype manufacture have widened our involvement to include many of the other EB processes.

It is impossible to give a full insight into the myriad aspects of EB technology in a few pages, but links give access to more detailed information where appropriate.

Electrons are charged particles with unique properties. They may be guided and focused into incredibly intense beams by using a combination of electrostatic and magnetic forces. Typical electron guns utilise a 'triode' gun system.

Typical electron gun columns incorporate various other elements such as lenses and deflection/alignment coils that allow beam manipulation.

Contact: electronbeam@twi.co.uk