CARBON-DIOXIDE SPUTTER SOURCE DEVELOPMENT AT OXFORD

Considerable development has taken place of the CO2 sputter source at Oxford. The use of a hemispherical ioniser has increased reproducibili ty of beam behaviour and a more open source design has helped to impro ve the initial cleaning of the targets. The operation of the source wi th graphite has also been investigated with C-12- currents in excess o f 300 muA achieved. Space charge effects in the injection system have been reduced by neutralisation which can be achieved using a ps dosing valve in the region of the first beam waist. Preliminary experiments have been done to test the feasibility of linking the source to a GC s ystem for GC-AMS.