Sufficient cusp field generated by permanent magnet for compact ECR ion source

摘要

Cusp modified minimum-B field configuration hag been used earlier for designing electron cyclotron resonance ion source (ECRIS) for 2.45 GHz mu-wave (microwave) frequency but the usage was very rare. Few ECRIS of this type were tested for >2.45 GHz using conventional minimum-B configuration comprising the axial field and radial multipole field created by permanent magnets. Some people used permanent magnet also to generate conventional field or cusp field configuration for such source. In this Note, it has been attempted to understand the problems of the old cusp field ECRIS. They are mitigated using available permanent magnet having very high remanence and coercivity and negatively-biased metal ring and disk in the mid-plane and at the injection end for designing and constructing a compact and very cost-effective ECRIS of the future.