Size Matters: Radiocarbon Dates of <200 µg Ancient Collagen Samples with AixMICADAS and Its Gas Ion Source
Résumé
For many of archaeology’s rarest and most enigmatic bone artifacts (e.g. human remains, bone
ornaments, worked bone), the destruction of the 500mg material necessary for direct accelerator mass spectrometry
(AMS) dating on graphite targets would cause irreparable damage; therefore many have not been directly dated. The
recently improved gas ion source of the MICADAS (MIni CArbon DAting System) offers a solution to this problem
by measuring gaseous samples of 5–100 μg carbon at a level of precision not previously achieved with an AMS
gas ion source. We present the results of the first comparison between “routine” graphite dates of ca. 1000 μg C
(2–3mg bone collagen) and dates from aliquots of gaseous samples of <100 μg C (<0.2mg bone collagen), undertaken
with the highest possible precision in mind. The experiment demonstrates the performance of the AixMICADAS
in achieving reliable radiocarbon measurements from <0.2 mg collagen samples back to 40,000 14C BP. The
technique has great implications for resolving chronological questions for key archaeological artifacts.