AMS ~(14)C SAMPLE PREPARATION AT THE KCCAMS/UCI FACILITY: STATUS REPORT AND PERFORMANCE OF SMALL SAMPLES

摘要

We present an overview of accelerator mass spectrometry (AMS) radiocarbon sample preparation and measurements, describing the technical upgrades that now allow us to routinely obtain 0.2-0.3 percent precision for 1-mg carbon samples. A precision of approx 1 percent on samples with 100 mu g of carbon can also be achieved. We have also developed graphitization techniques and AMS procedures for ultra-small samples (down to 0.002 mg of carbon). Detailed time series are presented for large and small aliquots of standards such as NIST OX-I and OX-II; FIRI-C and -D; IAEA-C6, -C7 and -C8; and ~(14)C-free samples.