A Direct Extraction H- Ion Source

A direct extraction H- ion source of the Penning design described by Dudnikovl has been built and tested. To date a beam of 108 mA has been extracted from a 10 ?? 0.5 mm2 slit and transported through a 90?? bending magnet into a Faraday cup at a duty factor of ~7 Hz ?? 700 ??s (0.5%). The duty factor limitation is imposed by operating temperature requirements so that at reduced arc current a dc beam of 4 mA has been reached.