A 60 mA DC H− multi cusp ion source developed at TRIUMF

This paper describes the latest high-current multi cusp type ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H−) of 60 mA of direct current at 140V and 90A arc. The results achieved to date including emittance measurements and filament lifetime issues are presented. The low current version of this ion source is suitable for medical cyclotrons as well as accelerators and the high current version is intended for producing large neutral hydrogen beams for fusion research. The description of the source magnetic configuration, the electron filter profile and the differential pumping techniques given in the paper will allow the building of an arc discharge H− ion source with similar properties.