The IAEA ¹⁴C Intercomparison Exercise 1990

Abstract

As a follow-up to the meeting of experts convened at the International Atomic Energy Agency (IAEA) in February 1989, and the International 14C Workshop held in Glasgow in September 1989, the 14C Quality Assurance Program was formulated. In a joint effort of several radiocarbon teams and IAEA staff, we have prepared a set of five new intercomparison materials. These are natural materials frequently used by radiocarbon laboratories. The materials were distributed to 137 laboratories in May 1990. In February 1991, a meeting of experts was convened in Vienna to evaluate the results, to determine the radiocarbon activity of the five samples expressed in % Modern (pMC) terms and to define the 13C/12C ratio, and to make recommendations on further use of these materials. We present here the results of the exercise and the agreed consensus values for each of the five materials and discuss the different analyses that were undertaken.

Ultra-Small Graphitization Reactors for Ultra-Microscale 14C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

“…Figure 3 illustrates that all "dead" standards do indeed fall on a single line, implying a common process blank. To determine the magnitude of fractionation introduced by the ultra-small reactors, graphite was produced from HOx-I, IAEA C-6 (Rozanski et al 1992), IAEA C-2 (Rozanski et al 1992), and IAEA C-1 standards, spanning a range of δ 13 C values, then subsequently combusted back to CO 2 by elemental analyzer. The δ 13 C value of the resulting CO 2 was measured by a dual-inlet isotope-ratio mass spectrometer.…”

Zinc Reduction as an Alternative Method for AMS Radiocarbon Dating: Process Optimization at Circe

“…value (errors in parentheses) (Rozanski et al 1992; NBS SRM 4990C certificate). The measured ζ variable is distributed around a mean value of -0.01, with a standard deviation of 1.21 (observed standard error on η = 33 samples was 0.21) (Figure 4).…”

Is Comparability of 14C Dates an Issue?: A Status Report on the Fourth International Radiocarbon Intercomparison

“…For more than 15 years, the radiocarbon community has participated in a series of laboratory intercomparisons in response to the issue of comparability of measurements as perceived within the wider user communities (Scott et al 1990;Rozanski et al 1992;Gulliksen and Scott 1995;Scott et al 1997). In this report, we provide an update on the current 14 C laboratory intercomparison and reflect on future issues linked to the laboratory intercomparison program, not least those resulting from a significant growth in the number of accelerator mass spectrometry (AMS) facilities providing routine dating of small samples (milligram size).…”