The Duoplasmatron is a type of Ion source invented by Manfred von Ardenne. It operates as follows: a cathode filament emits electrons into a vacuum chamber. A gas such as argon is introduced in very small quantities into the chamber, where it becomes charged or ionized through interactions with the free electrons from the cathode, forming a plasma. The plasma is then accelerated through a series of at least two highly charged grids, and becomes an ion beam, moving at fairly high speed from the aperture of the device. Later development by Harold R. Kaufman resulted in the Kaufman Duoplasmatron which has been used for applications as diverse as semiconductor manufacture, and spacecraft propulsion.
- Brown, I.G., "The Physics and Technology of Ion Sources", Wiley-VCH (2004), p.110