ENHANCED HIGH VOLTAGE HOLDING UNDER VACUUM BY FIELD INDUCED ADSORPTION OF GAS ON METAL SURFACES

The energy of future neutral beam injector heating systems of fusion power plants ranges from 1 to 2 MeV. They are based on powerful hydrogen negative ion electrostatic accelerators where electrodes are polarized by high-voltage DC power supplies. The bushing is a high-voltage feed-through that allows supply of the accelerator electrodes. In this paper, a new high-voltage bushing concept is presented. The main advantages of the concept are a likely reduction of the electron field emission by the field induced gas adsorption effect in the inner part of the bushing where the electric field intensity is highest. This effect also yields to a reduction in size, and mechanical simplification of the device.