Results from ZMEVVA: A new source for heavy-ion accelerators

We are developing a new approach for heavy ion beam injection (e.g., into the Relativistic Heavy Ion Collider [RHIC] at BNL). While conventional Metal Vapor Vacuum Arc (MEVVA) ion sources (I.G. Brown, Rev. Sci. Instrum. 65, 3061 (1994).) can produce up to hundreds of milliamps or more of several-times-ionized metal ions (e.g., U/sup 3+/), the recent results from Batalin et al. (V.A. Batalin et al. ITEP, Moscow, Reprints 18-93 (1993), 33-94 (1994); Proc. EPAC 1994, p.1453.) indicate that the addition of an energetic electron beam (EMEVVA) may lead to considerably higher charge states (e.g., U/sup 17+/). An alternative way to produce the electron beam is ZMEVVA, in which a z-discharge plasma is used to enhance multiple ionization. As the vacuum arc plasma plume expands into a magnetized drift region, a z-discharge is triggered in the drifting metal plasma. The ions are then extracted and analyzed using a time-of-flight system. We report recent results using applied discharge voltages from 1 to 2 kV.