Pulsed Cryogenic Ion Source for Pure Beam Extraction

Recent work on pulsed cryogenic ion sources at the Tokyo Institute of Technology are reviewed briefly. Surface flashover processes of low-temperature dielectric materials are investigated experimentally in connection with the cryogenic ion sources. Values of dc or pulse breakdown voltage are measured, and fast-frame photographs are taken to observe the luminous surfaces. Characteristics of magnetically insulated cryogenic diodes with externally applied radial fields are clarified as a function of the anode temperature. Hydrogen, nitrogen, or argon ion beam is extracted from each ice on the anode surface of the cryogenic diode.