Development of a compaction source with a hot hollow cathode

Summary form only given. A 16 mm diameter, 30 mm long compact ion source with a hot hollow cathode was developed. A hot hollow cathode having a coaxial current flowing path does not produce any magnetic field. Therefore, the hot hollow cathode does not disturbed plasma until heating by several tens ampere of cathode current. Two tantalum tubes which were connected at one side tip of both tubes consist to the hot hollow cathode. The hot hollow cathode was adapted to a Bernas-type ion source to confirm a plasma production and beam extraction performance. The hot hollow cathode produced a clearer and more focused shape plasma along the external magnetic field of a Bernas-type ion source than by a hair-pin cathode. The extraction singly charged ion beam from the plasma with a hot hollow cathode was increased more than twice from the ion source with a hair-pin cathode. The multiply charged ion beam current was enhanced up to more than five times the current produced with a hair-pin cathode. A compact ion source with an extraction axis aligned to the axis of the cathode was designed and tested. The ion source was cylindrical in shape with 60 mm in diameter and 160 mm in length. The dimensions of the hot hollow cathode were 2 mm the diameter of an inner tube, 3.2 mm the diameter of an outer tube and about 30 mm length. A source gas was supplied through into an inner tube of the hot hollow cathode. A source gas ran through the inner tube of the cathode at a temperature high enough to yield enough thermionic electron emission. Thus, it is expected to enhance a dissociation of molecular species. As a preliminary test, argon gas discharge was observed at less than 20 V discharge voltage at 0.2 pa gas pressure and 60 A cathode heating current. The ion source had a single stage extraction system. A diameter of an extraction hole was 4 mm and gap length 1 mm. 1.0 mA extraction current at 50 V/ 1120 mA, 0.02 Pa Argon discharge and 1 kV extraction voltage was observed.