Issue Date
1998-01-01Keywords
combustionisotope fractionation
mathematical methods
size
C 14 C 12
accuracy
graphite
native elements
data processing
accelerator mass spectroscopy
mass spectroscopy
spectroscopy
sample preparation
methods
C 14
carbon
isotopes
radioactive isotopes
carbon dioxide
stable isotopes
absolute age
Metadata
Show full item recordCitation
Pearson, A., McNichol, A. P., Schneider, R. J., Von Reden, K. F., & Zheng, Y. (1998). Microscale AMS 14C measurement at NOSAMS. Radiocarbon, 40(1), 61-75.Journal
RadiocarbonDescription
From the 16th International Radiocarbon Conference held in Gronigen, Netherlands, June 16-20, 1997.Additional Links
http://radiocarbon.webhost.uits.arizona.edu/Abstract
Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605 degrees C. Measured 14C/12C ratios of the resulting targets are affected by machine-induced isotopic fractionation, which appears directly related to the decrease in ion current generated by the smaller sample sizes. It is possible to compensate effectively for this fractionation by measuring samples relative to small standards of identical size. Examination of the various potential sources of background 14C contamination indicates that the sample combustion process is the largest contributor, adding ca. 1 micrograms of carbon with a less-than-modern 14C concentration.Type
Proceedingstext
Language
enISSN
0033-8222ae974a485f413a2113503eed53cd6c53
10.1017/S0033822200017902