Self-cooling of highly charged ions during extraction from electron beam ion sources and traps

Evaporative self-cooling can produce a dramatic reduction in the temperature and emittance of ions extracted from electron beam ion sources and traps for favorable values of ion density and charge if the trapping potential is removed slowly. For existing electron beam ion traps, calculations predict that 20% of trapped Ar18+ ions can be extracted with an average emittance 30 times lower than the uncooled emittance. It may be possible to construct sources of very-highly charged ions with an absolute brightness of order 2x10(10) ions/mm(2) mrad(2) s, a value more than four orders of magnitude larger than that of existing highly charged ion sources. (C) 1999 Elsevier Science B.V. All rights reserved.