In 1981, the first 14C and Archaeology Symposium was organized because it was felt necessary to have a symposium that focused on the specific problems related to the use of 14C dating in archaeology. The dating method has been constantly changing and approving itself technically as well as in the application of the method. The relationship between the archaeologists and the 14C dating laboratories has, however, never been straightforward. For a lot of 14C laboratories, archaeology was not their core business. For archaeologists, the main problem arose from an insufficient knowledge of natural sciences. The last decennia, however, 14C and archaeology are growing towards one another. One of the reasons might be the introduction of small exclusively 14C-dedicated machines and the availability of fully automatic graphitization lines.

The present research is focused on the dating of the Oglakhty burial ground, the key site of stage I of the Tashtyk culture. Despite the numerous well-preserved burials of that type investigated at the Oglakhty complexes, their chronological position has remained unclear. From the early 20th century until the present, 2 different time periods had been identified for the Tashtyk burials: (1) from the 1st century BC until the 1st century AD and (2) from the 1st until the 2nd century AD. New data obtained in the 1990s suggested a different age for Tashtyk burials, namely the 3rd–4th centuries AD. This considerable shift in chronology needed to be checked with independent data. The chronological position of one of the Oglakhty burials, tomb 4, has been investigated with the use of wiggle-matching, applied to wooden logs used in the construction of tomb 4. The resulting dates for this burial strongly suggest its age as being limited to the 3rd–4th centuries AD, which is corroborated by the archaeological dates of the imported artifacts found in the grave and which is in agreement with the chronological position of the Oglakhty site, as proposed by previous investigations.

Regional offsets from Northern Hemisphere radiocarbon (14C) calibration curves are widely recognized for monsoon Asia and often hinder accurate 14C dating. In this paper, we explore the possible linkage between summer monsoon intensity and 14C offsets using tree-ring δ18O and 14C data from Thailand. We developed a 297-yr floating tree-ring δ18O chronology comprising seven teak log-coffin samples from the Ban Rai rock shelter site, northwestern Thailand. The outermost ring of our chronology was estimated to date from 358–383 CE, within a 95.4% (2σ) probability range, based on a total of 10 14C measurements that were wiggle-matched against a mixed calibration curve evenly weighted from the IntCal20 and SHCal20 curves. Backward trajectory analysis showed that an intensified (weakened) summer monsoon detected in a modern tree-ring δ18O chronology was most likely to be induced by increased (decreased) air mass transport from the tropical Indian Ocean, which is an area of intense upwelling where the 14C concentration is lower than the atmospheric 14C level. However, partly because of the limited sample size and dating uncertainty, the direct linkage between the tree-ring δ18O series and 14C records obtained from our teak log-coffin samples could not be statistically verified.

In 2016, a burial chamber hewn into limestone was discovered at Khirbet Aqabet Al Qadi on the northwestern slope of Mount Ebal, 2km north of the city center of Nablus. The floor of the chamber is 3.15 × 2.9 m and the height averages 1.8 m. A movable closure at the entrance consists of a limestone slab. The burial chamber houses four sarcophagi. The aim of this case study is to give information not only on the burial chamber but also, for the first time in the region, on human remains. Stable isotope analysis of a human bone sample enabled us to obtain dietary information on one individual. Due to low collagen content, the sample did not allow precise dating but it can be placed between 50 BC and 50 AD. Systematic illegal excavation and looting at funerary sites in the Nablus area has caused material for potential information to be missing at the site. Nonetheless, the dietary information obtained supports other material finds indicating Mediterranean agricultural use of the land. Our evidence demonstrates that the site dates to between the 1st and 3rd centuries AD.

The Gaspereau Lake Reservoir Site Complex in Nova Scotia, Canada, yielded a large ceramic assemblage that permitted the first fine-grained analysis of ceramic change in the region at the Middle–Late Woodland Transition from ca. 1550 BP to ca. 1150 BP. The aim of this study was to refine the standard regional chronology first proposed by researchers J B Petersen and D Sanger. To do this, ceramics were directly dated using accelerator mass spectrometry (AMS), and the assemblage was categorized and analyzed to identify clusters of attributes. Ten AMS dates were acquired on carbonized food residue on the interiors of pottery and yielded the largest continuous ceramic sequence in the Maritime Provinces of Canada. This sequence was used to infer a change in manufacturing practices between the Middle (2150–1300 BP) and Late (1300–500 BP) Woodland periods and to propose five new subperiods between 1650 BP and 950 BP. Increasing incidence of coil breaks and temper percentage from the Middle to the Late Woodland were found to be chronologically sensitive. The analysis showed that, at Gaspereau Lake, a gradual shift from finely decorated and manufactured pottery to expediently made pottery suggests that pottery was made in larger numbers to support large-scale gatherings.

A workshop on atmospheric radiocarbon measurements was held in conjunction with the 21st International Radiocarbon conference in July 2012. The main topics were intercomparison of measurements of 14C in atmospheric CO2, the potential for use of gas standards for atmospheric 14C measurements, reporting of uncertainties, and expansion of intercomparison activities to other atmospheric trace gases. This report documents the discussions and conclusions of this workshop.

It is known that 12C beam transmission through the accelerator decreases at high beam currents. This effect depends on machine design and varies across different types of AMS instruments. For beam currents of about 100 μA, the effect is small on the 500 kV tandem CAMS unit, whereas beam saturation is observed for similar high beam currents on the 250 kV SSAMS unit. While this effect is very evident for high 12C beam currents, we have also observed that even the 13C beam is found to suffer modest transmission loss with beam current. As a result, the 13C/12C ratio does not remain constant with beam current. By correcting for the effects of 12C beam saturation and decreased 13C transmission, we have obtained online δ13C values that are more accurate and precise at moderately high beam currents for SSAMS.

The earliest years of photography were full of experimentation and innovation; many photographers from this era carefully documented their experimental procedures. Consequently, it is possible to reproduce historically accurate photographs and negatives today. One of the oldest forms of photographic technology is the waxed paper negative, popular during the mid-19th century. It consists of a photosensitive sheet of writing paper coated with a layer of wax to render it transparent. Modern waxed paper negatives made using 19th century paper can potentially pass for historically significant 19th century negatives. This poses problems to museums and others interested in studying or collecting authentic 19th century photographic images. We have developed methods for separating the organic components of waxed paper negatives and measuring their radiocarbon content as a means of distinguishing between modern and historic waxed paper negatives. By detecting the presence or lack of bomb carbon in a given negative, this process can act as a tool for authentication. We have mainly focused on the extraction and 14C measurement of the wax component, reasoning that modern photographers might have easy access to 19th century paper, but would less likely use 19th century beeswax.

Natural C14 measurements at the Institute of Physical and Chemical Research (RIKEN) became routine in 1962. The counters presently used are made of stainless steel with a volume of about 2.7 L. They are surrounded by 2.5 cm of pure lead, a ring of 22 propane gas-flow anticoincidence counters, about 10 cm of boric acid and 20 cm of iron. When filled with dead CO2 up to 2 atm, they gave a background counting rate of about 9 cpm (Hamada, 1960).

In this article, results obtained for geologic and archaeologic samples since 1962 are described. Dates have been calculated on the basis of the C14 half-life of 5568 yr, and 95% of NBS oxalic acid as modern standard. Correction for isotopic fractionation was not applied.

Radiocarbon measurements have been continued on a variety of projects and materials. Chemical and counting procedures remain the same as indicated in R, v 20, p 274-282. Dates are calculated using the Libby 14C half-life of 5568 years; errors are reported as one-standard deviation (1σ) based only on statistical counting uncertainties in background, modern standard, and sample activities. All samples for which 13C/12C ratios are available are corrected for isotopic fractionation by normalizing to —25‰. A 400 year reservoir age correction has been applied to marine carbonates.

A kohitsugire is a paper fragment from an old manuscript written mainly in the Heian and Kamakura periods. Although they contain significant information for historical, literary, and paleographical study, because of their antique handwriting and description of historical incidents, there are many copies and counterfeits written several centuries later. In this study, radiocarbon ages of kohitsugire were measured by accelerator mass spectrometry (AMS). On the kohitsugire attributed to the famous calligraphists in the Kamakura period (Fujiwara no Sadaie and Prince Munetaka), 14C dating indicated that they were not genuine and should be excluded from the materials for study of the calligraphists. Calibrated 14C ages of the kohitsugire attributed to Fujiwara no Yukinari indicated the middle Heian period. This calligraphy was written on Tobikumogami paper, which has a billowing cloud pattern decorated with indigo-blue-dyed fiber. Although it was commonly accepted that the Tobikumogami is peculiar to the middle 11th to early 12th century, the results from 14C dating also suggested that the origin of the Tobikumogami would date back to the last of the 10th or the early 11th century, when Fujiwara no Yukinari flourished as a calligraphist. Calibrated 14C ages of the kohitsugire attributed to Nijo Tameuji and Reizei Tamesuke showed that they are fragments of old manuscripts describing lost tales and were written in the 13th–14th century. Consequently, 14C dating clarified the existence of ancient tales which had been unknown and indicated their worth as a material for the study of classical Japanese literature.

A simple way to upgrade the Peking University 500kV NEC radiocarbon facility (CAMS) for 10Be measurements is presented. In a first phase, a silicon nitride foil as passive boron degrader was mounted in front of the electrostatic deflector near the focal plane of 10Be. The Si detector at the end of the beam line was replaced with a high-resolution ΔE-Eres gas ionization chamber. In addition, a Faraday cup for the measurement of 9Be1+ was installed. Tests with this arrangement showed promising results: a 10Be/9Be background level of 3.4 × 10–14 and an overall transmission for 10Be of 2.2% were obtained. Measurements of standards showed very good stability and reproducibility. In the next step, it is planned to add a second magnet to reduce the background and to partly compensate losses due to energy and angular straggling in the degrader foil by the energy and angular refocusing effect of a magnetic sector field. With this final arrangement, a performance with 10Be/9Be background levels at 10−15 and 10Be overall transmission of 6–7% can be expected. The design proposed in this paper has the advantage that the modifications can be realized in a rather inexpensive way and that the measurement performance for 14C will not be affected.

Precise manometric pressure, volume, and temperature (P-V-T) measurements of carbon in samples, standards, and blanks are critical for radiocarbon studies. While P and T uncertainties depend on instrument choice and environmental stability, V uncertainties depend on their method of measurement and are often overlooked. We used numerical simulations and error propagation to find optimum procedures for measuring “cold-finger” volumes equipped with capacitance diaphragm gauges (CDGs) by two common application of Boyle’s Law: cryogenic transfers and serial gas expansions with a reference flask of known volume. Minimum relative uncertainties of cold-finger volumes are comparable for these two methods (∼0.002), but the serial gas expansion method is preferred due to its convenience. Serial gas expansions can be performed to high precision by using dry air, an initial pressure ∼76% full-scale (e.g., 760 Torr), and a reference flask with an optimal volume based on preliminary estimates of cold-finger volumes and an empirical power function. The volumes of cold-fingers ≥ 12 cm3 can be determined with minimum achievable relative uncertainties of 0.0021 to 0.0023. This limit translates to minimum achievable relative uncertainties of 0.0026 to 0.0027 for P-V-T measurements of moles of gas simulated here.

Study of the dependence of core top ages for G menardi and G sacculifer on water depth in cores of low sedimentation rate (∼2cm/103 yr). The study was initiated by Lisa Dubois of Brown University on cores originally studied by Curry and Lohmann of Woods Hole Oceanographic (see Table 2).

About ten radiocarbon laboratories operate in Japan and have dated more than 25,000 samples since 1960. Geomorphic development and human activities since the last glaciation have been documented with radiocarbon determinations. In order to apply these dates more effectively, the author finds it necessary to create and maintain a radiocarbon database system, which he has been doing since 1985, using a personal computer system linked to a telephone line. A researcher may access, search and retrieve data from the Radiocarbon Database System of Japan.

The design of FIRI is such that for each laboratory, we have some basic, though limited, information on the laboratory procedures, including the method of pretreatment applied to the samples, the modern standard, and the background material used. These can be considered as factors in the experiment and through statistical analysis, we can investigate whether they offer a statistically significant explanation of the observed variation. The different levels of the factors are described in Table 4.1. In addition, the laboratory type is also considered as a further factor (with 3 levels of LSC, GPC, and AMS).

Rýzmburk Castle is one of the largest and most important medieval castles in Bohemia, documented since 1250 AD. Its North tower is assumed to be built in 1260–1300 AD. To test this assumption, the surface layers of mortar were inspected for the presence of charcoals suitable for radiocarbon dating, and 10 charcoals were found. The charcoals probably originated from wood used for lime burning. The results of radiocarbon dating using accelerator mass spectrometry agree with the historical estimation. Single post-1287 sample indicates that the building date might be refined to 1287–1300 AD.

This list begins a program of publishing our large backlog of unpublished dates. The dates listed here are not a specific block of dates but simply those ready for publication. In many cases we have received comments from submitters, to whom we are grateful. Where no comment is included, none was received.

The automatic β-counting system plays a significant role in obtaining high-level reproducibility and reliability in conventional radiocarbon dating. I review here the results achieved by using the “Fully Automatic Radiocarbon Dating System” developed by Omoto (1982). Since setting up the system in 1981, I was able not only to save operator time in β counting, but also to obtain accurate dates with only minimal uncertainties. Another positive result was the introduction of the automatic voltage correction program, which produced excellent results for counting sample materials over a long period.