The AMS Golden Valley laboratory is equipped with two accelerator mass spectrometers: the AMS facility from the Budker Institute of Nuclear Physics (BINP) and the Mini Carbon Dating System (MICADAS-28) from Ionplus AG and two graphitization systems: the Automated Graphitization Equipment (AGE-3) from Ionplus AG and the Absorption-catalytic setup (ACS) developed at the Boreskov Institute of Catalysis (BIC). The ACS was designed for graphite preparation from labeled biomedical samples, dissolved organics, and dissolved or gaseous carbon dioxide but has proven to be suitable for the traditional dating of objects no older than 35,000 years. Here we present two series of AMS data for the samples from Glasgow International Radiocarbon Inter-comparison (GIRI), prepared using AGE-3 and ACS, and then measured on MICADAS-28. The mean value of the background F14C was 0.0024 ± 0.0009 and 0.012 ± 0.003 for AGE-3 and ACS, respectively, and both methods gave reproducible results for the OXI.

The AMS Golden Valley radiocarbon analysis laboratory is equipped with two accelerator mass spectrometers: AMS facility from Budker Institute of Nuclear Physics (BINP AMS) and MIni CArbon DAting System (MICADAS-28) from Ionplus AG and two graphitization systems: Automated Graphitization Equipment (AGE-3) from Ionplus AG and Absorption-catalytic setup developed in Boreskov Institute of Catalysis (ACS BIC). The laboratory provides routine 14C analyses of various samples: collagen, cellulose, humic acids, carbonates from sediments, etc. The main focus of the laboratory is to determine the age of archaeological artifacts by radiocarbon dating. This work presents a comprehensive description of the BINP AMS facility, with its operation compared with that of MICADAS in the same laboratory. In 2022, the AMS Golden Valley laboratory participated for the first time in the Glasgow International Radiocarbon Inter-comparison (GIRI). The samples were graphitized on the AGE-3 and subsequently measured in both AMS facilities. A comparison of the results of the two series of experiments, namely AGE-3 + MICADAS-28 and AGE-3 + BINP AMS, is given.

GIRI (Glasgow International Radiocarbon Intercomparison) was designed to meet a number of objectives, including to provide an independent assessment of the analytical quality of the laboratory/measurement and an opportunity for a laboratory to participate and improve (if needed). The principles in the design of GIRI were to provide the following: (a) a series of unrelated individual samples, spanning the dating age range, (b) linked samples to earlier intercomparisons to allow traceability, (c) known age samples, to allow independent accuracy checks, (d) a small number of duplicates, to allow independent estimation of laboratory uncertainty, and (e) two categories of samples—bulk and individual—to support laboratory investigation of variability. All of the GIRI samples are natural (wood, peat, and grain), some are known age, and overall their age spans approx. >40,000 years BP to modern. The complete list of sample materials includes humic acid, whalebone, grain, single ring dendro-dated samples, dendro-dated wood samples spanning a number of rings (e.g., 10 rings), background and near background samples of bone and wood. We present an overview of the results received and preliminary consensus values for the samples supporting a more in-depth evaluation of laboratory performance and variability.

The SUERC Radiocarbon Laboratory reports approximately 3000 unknown samples per year with an additional 1200 samples processed for quality assurance purposes. In addition to the primary OxII standard (SRM-4990C) required for AMS batch normalization, secondary “known-age” standards have been used over many years to evaluate individual batch quality. These have included wood (as prepared alpha-cellulose), barley mash, humic acid, a background mammoth bone, known-age bones, and a whisky sample. In this paper, we present some of the results gathered over routine laboratory operation (for more than 10 years) and examine the results illustrating how they are being used to monitor and quality assure performance. Since many of these samples have also been used in the Glasgow intercomparisons, we will also reflect on the results, as well as the actual and potential uses of such samples.

A laboratory intercomparison project was carried out on 20 annually resolved late-wood samples from the Danish oak record. The project included the following three laboratories: (1) the University of Arizona AMS Laboratory, University of Arizona, USA (AA); (2) HEKAL AMS Laboratory, MTA Atomki, Hungary (DeA); and (3) Aarhus AMS Centre (AARAMS), Aarhus University, Denmark (AAR). The large majority of individual data points (96%) lie within ±2σ of the weighted mean. Further assessment of the accuracy associated with the individual laboratories showed good agreement, indicating that consistent and reliable 14C measurements well in agreement with each other are produced at the three laboratories. However, the quoted analytical uncertainties appear to be underestimated when compared to the observed variance of differences from the geometric mean of the samples. This study provides a general quality check of the single-year tree-ring 14C measurements that are included in the new calibration curve.

The application of accelerator mass spectrometry radiocarbon (AMS 14C) dating in forensics is made possible by the use of the large excursion of the 14C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of forensics still appears to be limited by different issues due to possible complex interpretation of the results. We present the results of an intercomparison exercise carried out in the framework of an International Atomic Energy Agency (IAEA) CRP-Coordinated Research Project between three AMS laboratories in Italy, Hungary, and Switzerland. Bone and ivory samples were selected with ages spanning from background (>50 ka) to 2018. The results obtained allow us to assess the high degree of reproducibility of the results and the remarkable consistency of the experimental determinations.

The ages of mortars and plaster can help reveal the history of monuments, their construction, or restoration times. However, these anthropogenic carbonates pose a challenge when it comes to separation of the atmospheric radiocarbon (14C) signal of the CO2 fixed in the mortar at the time of consolidation, i.e., the time of binder formation. The variety and heterogeneity of mortars require individual assessments of each sample and 14C results. Here we present our current preparation method and summarize experience based on results collected during the last 20 years of mortar dating at the ETH laboratory.

We studied a suitable procedure for preparing of water samples used in radiocarbon intercomparisons involving dissolved inorganic carbon (DIC). The water samples must have inter-batch consistency and stable 14C concentrations and no sterilizing agent (e.g., HgCl2) should be added, in order to avoid the production of hazardous material. Six water samples, containing widely different amounts and types of salts, DIC, and 14C concentrations (1–100 pMC), were prepared in order to assess the procedure. Sample consistency was investigated through δ13C and chemical compositions; their low variabilities indicate that our procedure can be applied to radiocarbon intercomparison. A specific sample preparation protocol was developed for this kind of applications.

Radiocarbon (14C) dating is routinely used, yet occasionally, issues still arise surrounding laboratory offsets, and unexpected and unexplained variability. Quality assurance and quality control have long been recognized as important in addressing the two issues of comparability (or bias, accuracy) and uncertainty or variability (or precision) of measurements both within and between laboratories (Long and Kalin 1990). The 14C community and the wider user communities have supported interlaboratory comparisons as one of several strands to ensure the quality of measurements (Scott et al. 2018). The nature of the intercomparisons has evolved as the laboratory characteristics have changed s. The next intercomparison is currently being planned to take place in 2019–2020. The focus of our work in designing intercomparisons is to (1) assist laboratories by contributing to their QA/QC processes, (2) supplement and enhance our suite of reference materials that are available to laboratories, (3) provide consensus 14C values with associated (small) uncertainties for performance checking, and (4) provide estimates of laboratory offsets and error multipliers which can inform subsequent modeling and laboratory improvements.

Each of the laboratory intercomparisons (from ICS onwards) has included wood samples, many of them dendrochronologically dated. In the early years, as a result of the majority of laboratories being radiometric, these samples were typically blocks of 20–40 rings, but more recently (SIRI), they have been single ring samples. The sample ages have spanned background through to modern. In some intercomparisons, we have examined different wood pretreatment effects, in others the focus has been on background samples. In this paper, we illustrate what we have learned from these extensive intercomparisons involving wood samples and how the results contribute to the global IntCal effort.

Over the past 30 years, the format of the radiocarbon (14C) intercomparison studies has changed, however, the selection of sample types used in these studies has remained constant—namely, natural and routinely dated materials that could subsequently be used as in-house reference materials. One such material is peat which has been used 12 times, starting with the ICS in 1988. Peat from Iceland (TIRI), Ellanmore (TIRI), Letham Moss (ICS, VIRI, and SIRI), and St Bees, UK (FIRI and VIRI) have been used, as well as a near-background peat from Siberia. In the main, these peat samples have been provided as the humic acid fraction, with the main advantage being that the humic acid is extracted in solution and then precipitated (the solution phase providing the homogenisation) which is a key requirement for a reference material. In this paper, we will revisit the peat results and explore their findings. In addition, for the last 8 years, the Letham Moss sample has been used in the SUERC 14C laboratory as an in-house standard or reference material. This has resulted in several thousand measurements. Such a rich data set is explored to illustrate the benefits arising from the intercomparison program.

We performed a new series of measurements on samples that were part of early measurements on radiocarbon (14C) dating made in 1948–1949. Our results show generally good agreement to the data published in 1949–1951, despite vast changes in technology, with only two exceptions where there was a discrepancy in the original studies. Our new measurements give calibrated ages that overlap with the known ages. We dated several samples at four different laboratories, and so we were also able to make a small intercomparison at the same time. In addition, new measurements on samples from other Egyptian materials used by Libby and co-workers were made at UC Irvine. Samples of tree rings used in the original studies (from Broken Flute Cave and Centennial Stump) were obtained from the University of Arizona Laboratory of Tree-Ring Research archive and remeasured. New data were compared to the original studies and other records.

Seven radiocarbon laboratories: Åbo/Aarhus, CIRCE, CIRCe, ETHZ, Poznań, RICH, and Milano-Bicocca performed separation of carbonaceous fractions suitable for 14C dating of four mortar samples selected for the MOrtar Dating Inter-comparison Study (MODIS). In addition, optically stimulated luminescence (OSL) analyses were completed by Milano-Bicocca and IRAMAT-CRP2A Bordeaux. Each laboratory performed separation according to laboratory protocol. Results of this first intercomparison show that even though consistent 14C ages were obtained by different laboratories, two mortars yielded ages different than expected from the archaeological context.

Radiocarbon (14C) dating is used widely in many projects as a basis for the creation and testing of chronological constructs. 14C measurements are by their nature complex and the degree of sample pretreatment varies considerably depending on the material. Within the United Kingdom and Europe, there are a number of well-established laboratories and increasingly, archaeologists are not just commissioning new dates, but also using statistical modelling of assemblages of dates, perhaps measured in different laboratories, to provide formal date estimates for their sites. The issue of comparability of measurements (and thus bias, accuracy and precision of measurement) from the diverse laboratories is one which has been the focus of some attention both within the 14C community and the wider user communities for some time. As a result of this but also as part of laboratory benchmarking and quality assurance, the 14C community has undertaken a wide-scale, far-reaching, and evolving program of intercomparisons, to the benefit of laboratories and users alike. This paper summarizes the most recent exercise, the Sixth International Radiocarbon Intercomparison (SIRI).

Combining atmospheric Δ14CO2 data sets from different networks or laboratories requires secure knowledge on their compatibility. In the present study, we compare Δ14CO2 results from the Heidelberg low-level counting (LLC) laboratory to 12 international accelerator mass spectrometry (AMS) laboratories using distributed aliquots of five pure CO2 samples. The averaged result of the LLC laboratory has a measurement bias of –0.3±0.5‰ with respect to the consensus value of the AMS laboratories for the investigated atmospheric Δ14C range of 9.6 to 40.4‰. Thus, the LLC measurements on average are not significantly different from the AMS laboratories, and the most likely measurement bias is smaller than the World Meteorological Organization (WMO) interlaboratory compatibility goal for Δ14CO2 of 0.5‰. The number of intercomparison samples was, however, too small to determine whether the measurement biases of the individual AMS laboratories fulfilled the WMO goal.

Residual stresses impact on a wide variety of industrial sectors including the automotive, power generation, industrial plant, construction, aerospace, railway and transport industries, and a range of materials manufacturers and processing companies. The X-ray diffraction (XRD) technique is one of the most popular methods for measuring residual stress (Kandil et al., 2001) used routinely in quality control and materials characterization for validating models and design. The VAMAS TWA20 Project 3 activity on the “Measurement of Residual Stresses by X-ray Diffraction” was initiated by NPL in 2005 to examine various aspects of the XRD test procedure in support of work aimed at developing an international standard in this area. The purpose of this project was to examine and reduce some of the sources of scatter and uncertainty in the measurement of residual stress by X-ray diffraction on metallic materials, through an international intercomparison and validation exercise. One of the major issues the intercomparison highlighted was the problem associated with measuring residual stresses in austenitic stainless steel. The following paper describes this intercomparison, reviews the results of the exercise and details additional work looking at developing best practice for measuring residual stresses in austenitic stainless steel, for which X-ray measurements are somewhat unreliable and problematic.

Les activités utilisant des rayonnements ionisants évoluent et nécessitent une surveillance dosimétrique adaptée. Dans le même temps, les techniques dosimétriques ont également évolué offrant notamment un choix de dosimètres électroniques plus important en particulier pour les neutrons ainsi qu’une diversification des techniques utilisables (TLD, OSL, RPL) pour la dosimétrie passive de routine. L’étude de poste est devenue incontournable afin de déterminerla façon la plus réaliste les caractéristiques de l’exposition dont résulte, entre autres, le choix des techniques passives et opérationnelles. Les différents dosimètres passifs aujourd’hui proposés par les laboratoires agréés présentent des performances globalement satisfaisantes. Par ailleurs, il existe sur le marché de multiples modèles de dosimètres électroniques susceptibles de couvrir les besoins associés à la dosimétrie opérationnelle. L’organisation d’intercomparaisons constitue un élément important du dispositif de contrôle de la bonne mise en œuvre des techniques de dosimétrie passive par les laboratoires agréés et des performances des dosimètres actifs dans des conditions réalistes d’utilisation. De telles intercomparaisons sont réalisées périodiquement, tant à un niveau national qu’international, afin de prendre en compte les évolutions des matériels, des pratiques et du plus grand nombre de situations possibles.