A HIGH-CAPACITY ION-SOURCE FOR AMS

A new ion source and sample manipulation system for accelerator mass s pectrometry (AMS), is being designed and built as a collaboration betw een IsoTrace and High Voltage Engineering Europa B.V. Since the initia l description of this system [W.E. Kieser et al., Nucl. Instr. and Met h. B 79 (1993) 613-616.], the vacuum system and the horizontal and ver tical sample transport systems have been completed and tested. The lat ter system has proved to be capable of changing from one sample to ano ther in under one second. Tests of the caesium guns used to generate t he primary sputtering beams for this system have shown that the ion so urce as a whole is capable of generating higher currents than previous ly thought possible, provided that proper space charge control is used for the primary beam and steering of the secondary beam is adjusted. This work has also led to investigations of a variety of strategies fo r exploiting the dual primary beam feature of this source, such as the use of neutral primary caesium beams, initially at low energies as a surface passivator for non-conducting samples and later at higher ener gies and fluxes for sputtering all types of samples.