Power Supplies for Cold Cathode Penning Discharge Ion Sources

For the generation of heavy ions at high charge states, the cold-cathode Penning discharge ion source requires a power supply capable of both the high potential essential for striking an arc and the high current for sustaining it. A series-regulated power supply developed at Oak Ridge provides up to 6 kV of striking voltage and up to 12 amperes of arc current. The power supply operates in a constant current mode with the arc voltage dependent on the gas pressure in the ion source. With this source in ORIC, the typical operating conditions are 5 to 10 amperes arc current, 600 to 2000 volts arc potential, and 5 to 20 kW power dissipation in the arc. A larger power supply is planned for extending the arc current to about 25 amperes. Various arrangements, including pre-regulators and multiple power supplies, are under consideration to reduce power dissipation in the series regulator tubes.