A reliable noble gas duoplasmatron for the 10 mA range

Duoplasmatrons have been employed at GSI as accelerator sources of multiply charged heavy ions, but extensive experience was collected also with singly charged noble gas ions. Other ion species can be produced from volatile compounds. provided that the cathode is protected from aggressive vapours by an additional noble gas. In a second source modification. the sputter duoplasmatron, ions are directly obtained from solid material. Recently the GSI-duoplasmatron has been equipped with plasma expansion cups in order to raise the ion current output. Generally, at least a factor of three is gained in beam intensity and other aspects of source performance are improved, too. A new cathode design considerably enhances life-time and reliability, permitting uninterrupted operation for a few hundred hours. Tables of measured ion beam currents are given.