TECHNOLOGY INNOVATIONS FOR VACCUM ARC ION SOURCES

ION SOURCES BASED ON VACUUM ARC TECHNOLOGY HAVE SEVERAL IMPORTANT ADVANTAGES. THEY CAN GENERATE A WIDE VARIETY OF METAL IONS, PRODUCE HIGH CURRENT FRACTIONS OF MULTIPLY-CHARGED IONS, AND ARE EASY TO OPERATE. UNFORTUNATELY, EXISTING ARC SOURCES HAVE TECHNOLOGICAL DRAWBACKS. A STABLE DISCHARGE REQUIRES HIGH CURRENT (>200A), LIMITING THE SOURCE PULSE LENGTH AND LIFETIME. IN THIS PHASE I PROJECT, IMPROVEMENTS TO ARC SOURCES BASED ON RECENT PUBLISHED EXPERIMENTS ARE DESCRIBED. THE GOAL IS TO ACHIEVE RELIABLE ARC TRIGGERING AND ION EXTRACTION EFFICIENCY. FOR PULSED APPLICATIONS, AN ALL-METAL ARC ASSEMBLY WITH A GAS TRIGGER FOR EXTENDED LIFETIME IS BEING DEVELOPED. DETAILED STUDIES OF AN IMPROVED EXTRACTION GEOMETRY ARE BEING CARRIED OUT, AND A METHOD TO CHANNEL ARC ELECTRON FLOW TO INCREASE AVAILABLE ION FLUX IS BEING STUDIED. FOR PHASE II, THE EXTRACTION OF MULTIPLY-CHARGED IONS THROUGH CONTROL OF THE SPACECHARGE POTENTIAL OF PLASMA EXPANDING FROM THE ARC WILL BE DEMONSTRATED. SOURCES WITH HEATED CATHODES WILL ALSO BE DEVELOPED TO REDUCE THE MINIMUM CURRENT NECESSARY TO SUSTAIN A STABLE ARC. WITH THIS APPROACH, IT MAY BE POSSIBLE TO OPERATE STEADY STATE SOURCES AT LOW ARC CURRENT.