Measurement of the spatial distribution and time stability of the hexapolar radial magnetic field used in the multicharge heavy ion source RECRIS

The Nd Fe B permanent hexapolar magnet of the 14.5 GHz multicharge heavy ion source RECRIS, realized in 1993, provides the radial magnetic field for the plasma confinement. The magnetic field measurement performed with a Hall probe showed a good axial uniformity of the radial field along the 200 mm of the magnet length. This uniformity is an important condition for an efficient confinement of the plasma of the ion source plasma chamber. The very long term stability of the magnetic field given by the permanent hexapolar magnet is also important having in view that a complex research facility as the ion source RECRIS is, has to be used for many years. The present magnetic field measurements showed a good concordance with the values obtained in a previous measurement performed two years ago, thus demonstrating a good long term stability of the hexapolar magnet parameters. (author)