C-14 measurements of sub-milligram carbon samples from aerosols

Accelerator mass spectrometry (AMS) at the milligram level is routinely performed, but it is difficult to go substantially below 100 mu g of carbon, we discuss various approaches for sample preparation, machine operation and data evaluation, to meet the special requirements of C-14 AMS measurements at the microgram-carbon level. Furthermore, we present first results obtained at the Vienna Environmental Research Accelerator (VERA) from C-14 measurements of a snow sample from Gaithersburg, Maryland, USA, prepared at the National Institute of Standards and Technology (NIST).