Status of the 14 C-AMS Laboratory in Brazil
K. D. Macario 1*, P. S. Gomes 1, R. M. Anjos 1, R. Linares 1, E. A. Queiroz 1, C. A. Carvalho 2, F. M. Oliveira 1, L. Cardozo 1
1 Physics Institute, Universidade Federal Fluminense
2 Physics Institute, Universidade Federal do Rio de Janeiro
The Brazilian Accelerator Mass Spectrometry program started 20 years ago and along this period collaborative projects have been developed, involving researchers from the Physics Institute of UFF, researchers from Archeology, Marine Geology, Geochemistry, Oceanography areas and external AMS laboratories, like ANU (Canberra), the PRIME Lab at Purdue University and the University of California-Irvine. Recently, a radiocarbon sample preparation laboratory was installed at the Physics Institute of the Fluminense Federal University in Brazil (L4C-UFF).
The AMS technique provides ultra-sensitive analysis of reduced size samples or even specific compounds since sample atoms are accelerated to high energies and measured using nuclear particle detectors. Sample preparation is extremely important for accurate radiocarbon measurement and includes chemical pre-treatment to remove all possible contaminants. For beam extraction in the accelerator ion source, samples are usually converted to graphite. At the L4C-UFF a stainless steel based vacuum line was constructed for carbon dioxide separation and graphitization is performed in sealed quartz tubes in a muffle oven. Successful graphite production is important to provide stable beam currents and minimize isotopic fractionation. Performance tests for graphite production are currently under way and isotopic analysis will soon be possible with the acquisition of a Single Stage AMS System by our group.
The Single Stage Accelerator produced by National Electrostatic Corporation is a 250 kV air insulated accelerator especially constructed to measure the amount of 14 C in small modern graphite samples to a precision of 0.3% or better. With the installation of such equipment at UFF in the beginning of 2012, the L4C-UFF will be the first independent laboratory dedicated to 14 C-AMS not only in Brazil, but in Latin America and will be open to collaborative researches.