A new facility for radiocarbon dating by accelerator mass spectrometry (AMS) was established in early 2015 at the Inter-University Accelerator Centre in New Delhi, India. The facility uses a 500 kV National Electrostatic Corporation (NEC) Pelletron accelerator for AMS measurements on graphite produced using the automated graphitization equipment (AGE) interfaced with an elemental analyzer and the carbonate handling system (CHS). A precision of better than 1‰ in the ratio of 14C/12C for the modern carbon sample and the background level of 1 × 10–15 from dead carbon sample has been achieved. This is the first dedicated accelerator of India only for AMS activities. This AMS system has the capabilities to perform 10Be and 26Al measurements as well.

This list contains the results of measurements of 172 radiocarbon samples made between January 1983 and December 1985. An additional 152 samples were measured, but these were submitted without detailed information, such as sample location and sampling depth; therefore, they were excluded from the list.

Two floating tree-ring chronologies were developed from oak timbers recovered during salvage excavations of a pre-Roman wharf in Este, a prominent center of the Veneti people, who lived in northeastern Italy during the Iron Age. Wiggle-match radiocarbon dating shows that one chronology spans the 10th and 9th centuries cal BC, and that the waterfront was probably built ∼800 cal BC. The second chronology apparently spans most of the 7th century cal BC, and is associated with a phase of construction about 2 centuries after the first. One of the samples gave what appeared to be anomalous 14C results that may best be explained as evidence of a short-term fluctuation in atmospheric 14C level, which can be seen in short-lived samples but is not apparent in the decadal or bidecadal calibration data. Both chronologies cover periods for which there are no other tree-ring chronologies in this region, and could become key to refining the local Iron Age chronology.

This radiocarbon laboratory began operation in 1980 using the benzene scintillation method. The benzene synthesizer is essentially identical with that of Ikeda (1976). A liquid scintillation counter is Aloca LSC-LB1. Samples dated are wood, charcoal, shell, and coral.

Pretreatment of wood and charcoal is a standard acid-alkali procedure, using 2% HCl and 2% NaOH at elevated temperatures. Charcoal is further heated in concentrated HNO3 for one hour, diluted in water, stands one night, and is washed and dried. Pretreated wood and charcoal are carbonized before combustion. The combustion products are passed over CuO, and are collected in an ammonium hydroxide bubbler system, and precipitated with calcium chloride.

Age offsets of accelerator mass spectrometry (AMS) assays on food residue taken from pottery vessels are well-documented in Europe and Asia in cultural contexts were freshwater aquatic products are attested, but are less well studied in North America. The present study examines a series of residue dates from the late prehistoric Central Plains of North America, comparing them with context dates run on annual plant remains. At least 13 of 23 assays are either incongruent with ages on annual plant remains, inconsistent among themselves within a site, or not credible for their cultural context. The conclusion is that food residue from ceramics does not produce consistently accurate dates. Some possible factors that may serve to introduce old carbon to residue samples are discussed. It also is noted that one's conclusions about the reliability of residue may be conditioned by the precision of the age determinations and by the goals of a specific chronology-building effort.

The radiocarbon dating laboratory of Queens College, CUNY, was established with the joint support of the Research Foundation of the City University of New York and the departments of Anthropology, Biology, Chemistry, and Earth and Environmental Sciences of Queens College. The laboratory has been operational since June, 1975 and is located in the basement of a two-story concrete and brick building.

Hikobe House is an important cultural property located in Gunma prefecture. It is one of the oldest manor houses in the Kanto region of Japan. The age of the Hikobe House has up to now been uncertain. There are no architectural records or memorandum tags that indicate when the Hikobe House was built. The living room of the Hikobe House has a style of the latter half of the 17th century, while the guest rooms exhibit a style more typical of the 16th century. So, architectural historians did not agree when the house was built. The wooden materials of the Hikobe House (zelkova, cherry tree, and Japanese red pine) are species that are not well suited to dendrochronology. Thus we investigated the materials of the Hikobe House using the radiocarbon (14C) dating method. Using both the 14C wiggle-match dating method on short tree-ring sequences and observations of remodeling traces of the materials, we were able to establish a credible age of Hikobe House as dating from the late 17th century.

While assessing the environmental impact of nuclear power plants, researchers have focused their attention on radiocarbon (14C) owing to its high mobility in the environment and important radiological impact on human beings. The 10 MW high-temperature gas-cooled reactor (HTR-10) is the first pebble-bed gas-cooled test reactor in China that adopted helium as primary coolant and graphite spheres containing tristructural-isotropic (TRISO) coated particles as fuel elements. A series of experiments on the 14C source terms in HTR-10 was conducted: (1) measurement of the specific activity and distribution of typical nuclides in the irradiated graphite spheres from the core, (2) measurement of the activity concentration of 14C in the primary coolant, and (3) measurement of the amount of 14C discharged in the effluent from the stack. All experimental data on 14C available for HTR-10 were summarized and analyzed using theoretical calculations. A sensitivity study on the total porosity, open porosity, and percentage of closed pores that became open after irradiating the matrix graphite was performed to illustrate their effects on the activity concentration of 14C in the primary coolant and activity amount of 14C in various deduction routes.

California's Northern Channel Islands have long been an epicenter of specialized fishing economies dating from 13,000 yr ago to the mid-19th century. With thousands of well-preserved shell middens, some dominated by single shellfish species and little to no material culture, it can be difficult to distinguish between specialized prehistoric and historical deposits at some site types. Beginning at least in the Early Holocene and continuing into the Historic period, California mussels, turban snails, and abalone were targeted for specialized collection and processing by Native Americans and later Chinese and Euro-American fishers. Here, we demonstrate how selective accelerator mass spectrometry (AMS) radiocarbon dating of specialized abalone processing camps can help distinguish between prehistoric and historical sites. While unconventional, our case study demonstrates the utility of 14C dating at sites less than 300 yr old.

The chronologic record of late Quaternary biota from central Alberta has broad implications for understanding the archaeological, geological, paleontological, and paleoenvironmental record of western North America. Radiocarbon dates on remains of Pleistocene megafauna were previously used as proxies for the advance and retreat of ice sheets across Alberta (e.g. Young et al. 1994; Dyke 2005), and are important for understanding landscape changes that likely influenced the timing of human dispersal into North America (Burns 1996). 14C records of Holocene age continue to refine our understanding of landscape change leading up to modern environmental conditions (Beaudoin 2003). Here, we report 15 14C dates from new and previously recorded sites in central Alberta, and one from just across the border within Saskatchewan (Figure 1).

The complex geographical scenario of Mexico allowed the cultural diversification and development of multiple cultures such as Tolteca, Teotihuacan, Mexica, and Maya, among others. Despite this rich cultural heritage, radiometric dating of Mexican cultural samples with radiocarbon (14C) began only in the 1980s and with accelerator mass spectrometry (AMS) in 2013. Analysis of 14C with AMS is the most widely used technique to date archaeological objects and cultural heritage. Since 2013, the Accelerator Mass Spectrometry Laboratory (LEMA) facility of the Institute of Physics at UNAM (IF-UNAM) has supported archaeological research in Mexico, but also investigation in other areas such as geology, physics, chemistry, and environmental sciences through the analysis of 14C, 10Be, 26Al, 129I, and Pu. The absolute dating with 14C continues to be the core of LEMA’s work, where different geographical scenarios of the country and climatic conditions present very diverse analytical challenges. This work presents a basic description of the AMS system of the LEMA laboratory and describes some applications that are currently being developed.

In 1968, H. Quitta, J. Herrmann, G. Kohl and P. H. Thong initiated cooperation between the Archaeological Institute in Hanoi and the Radiocarbon Dating Laboratory in Berlin. Since 1969, the Berlin 14C laboratory has measured 215 14C dates from 65 archaeological sites in Vietnam. As a result, important problems in Vietnamese archaeology have been recognized and partially solved with the aid of a secure chronological framework.

Processing and measurement of 200 biomedical samples has provided an opportunity to better understand the characteristics of accelerator mass spectrometry (AMS) analysis of such samples. We have utilized established procedures (Vogel 1992) and developed new methods for handling various biological samples. We have included secondary standards of known isotope ratio for all assays. A method of determining maximum precision for each unknown sample value is also reported. The presented data are an update of the ongoing radiocarbon AMS biomedical program at Purdue University.

Radiocarbon (14C) is a key radionuclide in the assessment of the safety of underground geological disposal facilities for radioactive wastes, and the understanding of the 14C behavior in stainless steel may lead to a re-evaluation of the near-surface repository for the disposal of wastes containing this radionuclide in high concentrations. To achieve this objective, leaching experiments were planned for two different scenarios. The first is where the leaching solution, NaOH solution of pH ca. 12 in aerobic conditions, simulates the expected conditions in a cement-based near-surface repository over long time periods. The other one uses an acid solution of 1M H3PO4, which has been proved as a high efficiency chemical removal agent of 14C in graphite. The development of both analytical methods and protocols to measure the release of 14C from the activated steel samples and the speciation in the aqueous and gaseous phase has been undertaken as part of the EC CAST (CArbon-14 Source Term) project. Analytical methods, suitable for identifying and quantifying low molecular weight organic molecules, comprise ion chromatography (IC) and gas chromatography coupled to mass spectrometry (GC-MS); they are described for aqueous and gaseous samples, respectively. In this paper the preparation of leaching experiments to measure the release of 14C and the results obtained are described.

Bone points were one of the major hunting implements in northern European hunter-gatherer societies. They differ in shapes, types, and manufacturing techniques. In this paper, we investigate 22 bone points from the territory of Lithuania, by studying their morpho-technological characteristics, direct dates, and adhesive residues. The majority are isolated finds, but four points were selected from excavated archaeological sites dated between the 5th and 3rd millennia cal BC. Most of the points belong to the barbed points category, but six slotted points were also studied. Of the 22, 16 previously undated points were sampled for accelerator mass spectrometry radiocarbon (AMS 14C) dating. The results of 10 successfully dated samples are discussed together with previously published 14C dates of bone points from the same region. ATR-FTIR analysis of adhesive residues from six points suggest that birch bark tar was used to haft barbed points and lithic inserts. The results reveal the diversity of types of Early Holocene bone points in the territory of Lithuania, while the slotted and Kunda-type bone points fall into narrow timeframes.

As an alternative to the accelerator technique, a simple, compact, small counter system has been developed and tested for routine 14C dating. Our small counter is an all-metal design made of the OFHC copper with quartz supports for the anode (25μm stainless steel). Careful selection of materials for the counter construction was made based on the measurements of the alpha contamination. Methane as the counter filling gave better resolution and gas gain stability, whereas CO2 gave lower background counting rate and it was easier to prepare and to handle. The long term run using CH4 showed that the gas gain remained stable within 1–2% for months after the initial drop which followed the counter filling. A 7-day counting period was sufficient to achieve a 3% relative standard deviation which was considered acceptable for routine dating of younger samples.