Selective removal of electrons from a Penning trap for negative ion autodetachment studies

It is shown that free electrons can be selectively removed from a Penning trap used to store heavy autodetaching negative ions by application of a series of small positive extraction pulses to one of the end electrodes of sufficient amplitude to extract the electrons yet not significantly perturb the heavy ion motion. This minimizes reattachment in the trap and increases the level of detailed information regarding ion lifetimes (and other properties) that can be obtained by monitoring the time evolution of the trapped ion population. (C) 2005 American Institute of Physics.