ABSTRACT
Electron cyclotron resonance (ECR) ion sources were first proposed by R. Geller in 1965 and H. Postma using their experience with mirror machines for fusion plasma studies. ECR ion sources for the generation of multiply charged ions need the highest possible plasma confinement to reach a high value of the product of electron density and confinement time, net, necessary for step-by-step ionization of the ions. This ECR ion source, called MAFIOS, delivered just moderate charge states as from a penning ionization gauge ion source because ion lifetime in the plasma was short. In 1975 Geller reported on a new ECR ion source design using a two-stage arrangement called SuperMAFIOS. In the presence of a sufficiently high magnetic field, electron cyclotron resonance heating of the electrons will occur. The higher magnetic field improves the confinement of the ions and in this way improves the charge state distribution.
