Developments in micro-sample C-14 AMS at the ANTARES AMS facility

We continue development of micro-sample radiocarbon sample preparation and AMS measurement at the ANTARES AMS facility. We routinely prepare samples containing 10-200 mu g of carbon using an iron catalyst with an excess of hydrogen in similar to 2.5 mL graphitisation reactors. These use a tube furnace to heat the catalyst to 600 degrees C and a Peltier-cooled water trap. Samples containing just a few micrograms of carbon can be prepared. We describe progress with a 0.5 mL laser-heated 'microfurnace' we are developing for the rapid and efficient graphitisation of similar to 5 mu g samples. Following operating experience with a prototype unit, work has commenced on the development of a second-generation device with the goal of fully automated operation with minimal introduction of extraneous carbon. Key to development of micro-sample C-14 AMS is the ability to reliably handle the graphite/iron sample and to mount it in the ion source target holder. We have developed a target holder that permits the sample to be loaded in a 1 mm diameter recess and rear pressed, ensuring a high quality surface finish, at a reproducible depth. Additionally we have developed a method for systematically aligning the sample stage with the cesium beam following ion source servicing. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.