Study of the characteristics of the ion beam extracted from an rf discharge in hydrogen under conditions of resonance

The characteristics of an ion beam issued from a hydrogen plasma have been studied. This plasma is obtained by means of a high-frequency discharge set under conditions of resonance. This resonance is obtained by inductively exciting the discharge in a transverse static magnetic field (perpendicular to the axis of the vessel). The resonance, of which we give the characteristics, permits a considerable increase in the ionization degree, and is therefore of interest as regards to ion sources. The beam of particles extracted from this discharge in resonance is studied by means of a magnetic analyzer. The energy distributions of the various ions consist of two parts. A comparative analysis of the characteristics of the beam, with and without resonance, shows that this resonance improves the properties of the system. In particular, for the H1+ ion, the energy dispersion is reduced to 25 eV and its proportion in the beam reaches 85%. This resonance proves to be a convenient and very simple means to obtain an H1+ ion beam.