7Be and 10Be concentrations in recent firn and ice at Law Dome, Antarctica

Over the past three years, the Australian National Tandem for Applied Research (ANTARES) AMS facility at ANSTO has been expanding its sample preparation and measurement capability, particularly for Be-10, Al-26 and Cl-36, During this time, ANSTO has continued its collaboration with the AAD and CSIRO Atmospheric Research on the measurement of cosmogenic isotopes from Law Dome, Antarctica. This research program has been supported by the construction of a dedicated geochemistry laboratory for the processing of ice and rock samples for the preparation of AMS targets. Here we present our first results for Be-10 concentrations measured in ice cores from three sites at Law Dome and describe the sample processing protocol and aspects of the AMS measurement procedure. These sites are characterised by an eightfold difference in accumulation rate with a common precipitation source. In combination with an established ice chronology, this has enabled some preliminary findings concerning the relationship between the snow accumulation rate and the measured Be-10 concentration for Law Dome during recent times. Additionally, we present Be-7 and Be-10/Be-7 measurements made for a few surface snow samples from Law Dome and Australia. (C) 2000 Elsevier Science B.V. All rights reserved.