Improving efficiency of plasma generation in H− ion source with saddle antenna

Abstract

Progress on the development of RF H− surface plasma source (SPS) with saddle antenna radio frequency (SA RF) discharge is considered. Several versions of new plasma generators with different antennas and magnetic field configurations were tested in the SNS small Test Stand. The efficiency of positive ion generation in plasma has been improved up to 0.18 A/cm2 per 1 kW of RF power at 13.56 MHz. A first prototype SA SPS with AlN chamber was installed in the SNS Test Stand that achieved current of H− ions up to 67 mA with an apparent efficiency of up to 1.6 mA/kW at RF frequency 2 MHz. A new version of the RF assisted triggering plasma source (TPS) has been designed, fabricated and tested. After cesiation emission of negative ions was increased from 1 mA to 5 mA with RF power 2.5 kW.