Design and Operating Characteristics of the Developmental H- Ion Source for 30-HZ Injection into the Argonne National Laboratory (ANL) Booster

A tandem-acceleration extended stationary arc duoplasmatron used for 1-Hz injection into the ANL booster is undergoing further development for 30-Hz operation. A 200-¿s, 50-MeV H- beam of at least 4 mA at 30 Hz will be required by the booster in its final development phase. To meet this requirement and to offset losses occurring in the linac and in the 750-keV and 50-MeV beam lines, the source must provide about 10 mA of H-ions. The present source produces negative ion currents of this order but the H-component is typically only 50% of the total beam; the remainder of the beam consists of ions with mass numbers in the neighborhood of 17. Source design will be discussed and data will be presented for typical operating conditions on the test bench and in the 75-keV terminal of the preaccelerator. Physical and chemical properties of materials which affect their suitability for use in pulsed ion sources as load-bearing structural materials, as functional components, and as vacuum walls will also be discussed.