Development of a Compact Ion Source with a Hot Hollow Cathode

A compact ion source with 14 mm diameter, 30 mm long discharge region was developed. A total size of the ion source including the beam extraction system was 60 mm in diameter and 160 mm in length. A high temperature coaxial cathode consisting of thin‐wall tantalum and tungsten tubes produced a discharge plasma. A source gas was supplied through the inner W tube of the coaxial cathode. A stable plasma of H2 was maintained with the discharge current of 2.0 A at 68 A cathode heating current. The optimum H2 gas pressure for ion beam extraction was 2×10−2 Pa. Hydrogen ion beam current was 120 μA (1 mA/cm2) at 2.0 A discharge current and 3.0 kV extraction voltage.