Error analysis at the NSF-Arizona AMS facility

This article presents a detailed explanation of the analytical method used to monitor and quantify measurement uncertainties at the NSF-Arizona Accelerator Mass Spectrometry (AMS) Laboratory. The method is applicable to all of the isotopes measured at the facility, including 14C, 10Be, 129I and 26Al. It is used for a variety of analytical purposes, including: calculation of random machine error (rme), calculation of radiocarbon dates, and as an indicator of daily and long-term machine performance. An algorithm for a diagnostic program used to monitor rme is described in detail. The performance of the AMS machine as measured by rme calculations is given for the most recent six month period. The long-term accuracy of the machine is discussed in terms of blind sample analyses made under the Third (TIRI), Fourth (FIRI) and Fifth (VIRI) International Radiocarbon Intercomparisons.