Development of a miniaturized duoplasmatron ion source.

A miniature sized duoplasmatron ion source mountable on a standard 34 mm diameter copper gasket flange was designed, and its performance was tested. A hollow cathode exited a stable discharge in the anode through a 3 mm diameter orifice of the intermediate electrode with less than 10 W discharge power for Ar. The extracted ion beam current was larger at a smaller discharge current and was maximum at 5 mA below, where the discharge became unstable. A Faraday cup located 200 mm downstream of the extractor detected 1 µA beam current at 5 mA discharge current with 390 V discharge voltage and 2 kV extraction potential. The source required higher discharge voltage for operation of hydrogen gas.