Experiments on a 14.5 GHz ECR source

The 14.5 GHz ECR4 source supplied to CERN in the framework of the Heavy Ion Facility collaboration provided Pb27+ operational beams to a new heavy ion linac in 1994. This source, which operates in the pulsed "afterglow" mode, has surpassed its design specification of 80 emA and now provides currents >120 emA on an operational basis for this charge state. Early tests showed the existence of extremely stable modes of operation which are fully exploited, and in 1996 the source was operational on a 24 hour basis for more than 2400 hours. Future operational requirements will benefit from the 10 Hz repetition rate of the source, but will require beam pulse length modulation. In the search for higher intensities a number of experiments have been performed on gas composition, RF power matching, extraction, plasma chamber liner and a biased dynode. The results of these tests will be presented.