Preliminary Results in the Development of 14C AMS at the University of Notre Dame's Nuclear Science Laboratory

Accelerator Mass Spectrometry (AMS) has proven the most sensitive method of measuring the amount of 14C present in a material for the purpose of radiocarbon dating. The AMS group at the University of Notre Dame’s Nuclear Science Laboratory has graphitized and dated both a sample believed to be sourced from the shipwreck of Le Griffon and an insect living in the depletion zone of the Alaskan glaciers provided by collaboration with the University of Notre Dame Department of Biology. Preliminary results of the former show a radiocarbon age of 1105±641 years, while preliminary results from the latter show a radiocarbon age of 6738±1290 years. Since Le Griffon sank in 1679, further study is required to determine the sample's source.

To achieve these results, each sample was measured in sets of four consecutive fifteen-minute trials along with 14C standards and blanks to calibrate the resultant counts. OxCal software was used to determine the age range of the sample from the calculated 14C/12C ratio.

The wide error margins are due to inconsistent count rates of 14C between trials. For a discussion of developments in measurement precision and capability, see Griffin Mulcahy’s CEU abstract, Carbon Dating for Interdisciplinary Research and Teaching: Developing 14C AMS at Notre Dame. The first results of these experiments will be presented at the CEU poster session and will include recent developments.