Improvement of the FEBIAD ion source at SPIRAL1

Abstract

The behaviour of the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source used at GANIL within the Target Ion Source System (TISS) of the “Système de Production d’Ions Radioactifs Accélérés en Ligne” (SPIRAL1) has been recently investigated to improve its performances and render them reproducible. Off line systematic studies of the evolution of working parameters (cathode shape, cathode heating, anode current) with time and temperature configuration have clearly shown the origin of issues was mainly related to an excessive temperature of the anode insulators. Modifications of the TISS have allowed the reduction of the anode current drift and an ionisation efficiency of 40Ar of 15%, stable over more than eight days. The system is still under improvement to stabilize its Ar ionization efficiency to 25%, which is the maximum observed during testing.

Ion-source development at the off-line LERIB test-facility at iThemba LABS

“…Modifications will be made inside the target-chamber in order to install and operate this source. A magnetic solenoid may also later be incorporated, as this should improve the ionization efficiency due to increased electron-beam focusing [6].…”