Ignalina NPP contains two Units with RBMK-1500 reactors. After shutdown, several Unit 1 systems and equipment were radiologically characterized and dismantled. The highest volume of reactor structures is attributed to the graphite stack of the reactor core, radiological characterization of which has not yet been performed. The stack can be visualized as a vertical cylinder 8 m high and 14 m diameter, made up of 2488 columns where each column is made up from several graphite blocks. The total mass of the graphite stack blocks is about 1700 tonnes. Therefore, the main goal of work reported in this paper was to estimate the inventory of 14C and other key radionuclides in the irradiated graphite by a combination of activity measurements and full 3D reactor graphite stack neutron activation modeling. Obtained results show that, based on the combination of modeling and measurement techniques, the total inventory of 14C in graphite stack is estimated at 3.22×1014 Bq at 9 years after Unit 1 reactor final shutdown. 14C activity is the highest among the analyzed radionuclides; the second highest is 60Co (~6 times lower).

Insoluble bone collagen is one of the most common materials used for high-resolution radiocarbon (14C) dating. Unfortunately, in some bones, poor preservation of the insoluble collagen excludes the possibility of dating. During the burial of the bone the collagen sometimes degrades into peptides. These peptides are soluble in the acid used to dissolve the bone mineral. It is known that under appropriate conditions, collagen has the ability to self-assemble. Here we exploit this capability and present a method for reassembling the soluble collagen peptides in archaeological bones and dating them. We treated the acid fraction generated during the demineralization of the bone by desalting and neutralizing the solution by dialysis. During the dialysis, the soluble collagen peptides reassemble and precipitate in the dialysis bag. We used FTIR spectroscopy to determine that the precipitated material is indeed collagen. The 14C dates obtained from the reassembled collagen were compared to the dates of “standard” insoluble collagen, extracted in parallel from the same bone. Although there are some divergences of the dates, 3 out of 10 samples could have been dated only by the reassembled collagen. This shows that collagen peptides reassembly can be a valuable tool for dating bones with little or no insoluble collagen.

The following radiocarbon measurements made since our last date list (R, v 17, p 112–120), are a partial list of projects and samples released for publication by the submitters. The technique employed is liquid scintillation counting of wholly synthesized benzene as described by Noakes et al (1965) and discussed in R, v 16, p 402–408. Errors are reported as one standard deviation. No correction factors are applied.

Deposits linked to abandonment have been widely recorded across the Maya lowlands, associated with the final activities occurring in ceremonial areas of Classic Maya centers. Various models have been applied to explain the activities that lie behind the formation of these contexts, including those linked to rapid abandonment (e.g., warfare) and others focused on more protracted events (termination rituals, and/or pilgrimages). Here, we assess Bayesian models for three chronological scenarios of varying tempo to explain the formation of peri-abandonment deposits at Baking Pot, Belize. Using stratigraphic information from these deposits, hieroglyphic dates recovered on artifacts, and direct dates on human skeletal remains and faunal remains from distinct layers in three deposits in Group B at Baking Pot, we identify multiple depositional events that spanned the eighth to ninth centuries AD. These results suggest that the processes associated with the breakdown of institutionalized rulership and its command of labor to construct and maintain ceremonial spaces were protracted at Baking Pot, with evidence for the final depositional activity dated to the mid-to-late ninth century. This interval of deposition was temporally distinct from the earlier deposition(s) in the eighth century. Together, these data offer a detailed view of the end of the Classic period at Baking Pot, in which the ceremonial spaces of the site slowly fell into disuse over a period of more than a century.

Since May 1952 the Isotope Physics Laboratory in Groningen has dated ca 13,000 14C samples. Due to lack of time the publication of date lists in Radiocarbon ceased in 1971 and probably will not be resumed in the standard way. Most dates have been published but they are scattered over a great variety of books and articles.

The Meade thrust, in southeastern Idaho, is a major element of the Western Overthrust Belt. The allochthon is of geo-economic importance both as a potential hydrothermal area and as the principal mining area within the Western Phosphate Field. To assist in the development of these two resources, an understanding of the regional ground-water circulation was sought. Geologic and hydrologic data from boreholes in this area are virtually nonexistent. Waterwell development in the area has not occurred because of the abundance of springs and only a few hydrocarbon exploration boreholes have been drilled. Thus, the problem lends itself to evaluation by isotope hydrologic and geochemical methods. Ten springs from within the thrust block and around its periphery were sampled for major ions, 2H/18O, and 14C/13C analysis. Data from these analyses and from field geologic evidence have identified two distinct flow regimes within the Meade thrust allochthon. Shallow flow systems lie above the impermeable Phosphoria Formation, usually within a few hundred meters of the surface. Most of the spring waters from this system are recent and cool. In all cases, they have mean subsurface residence times of less than a few hundred years. The deeper flow systems which lie below the Phosphoria formation are hydraulically isolated from the shallow system. Warm waters from these springs have 14C contents suggesting mean ground-water residence times on the order of 15,000 years. Although these waters could have circulated to as deep as 1900m, 2H/18O results show that high temperatures were never reached. There is no evidence to suggest that water from beneath the Meade thrust has contributed to the circulation in the allochthon.

Until recently, the only chronometric technique applied to Sahulian archaeological sites was 14C dating; the ages obtained rarely exceeded 40,000 bp. Belief that the region was first colonized around that time has recently been shaken by luminescence dates from several archaeological sites in northern Australia that suggest people arrived between 60,000 and 55,000 bp. The ensuing debate over their validity revealed that some participants misunderstood luminescence dating and the temporal limitations of 14C dating, illustrated here through a discussion of the tempo and mode of Sahulian colonization. Radiometric techniques cannot distinguish between the models proposed because they are unable to resolve temporal issues that occur within their limits of error.

The following list covers the measurements in our institute from January 1962 to March 1963. Sample preparation and conversion into acetylene are described by Wendt, Schneekloth and Budde (1962).

An Oeschger counter with an effective volume of 1.5 L came into operation in 1962. It is shielded by 4 cm of iron and 10 cm of lead. The background amounts to 2.24 cpm, the standard C14 counting-rate 17.05 cpm. In routine measurements, the impure acetylene, after a four-week storing period, is put into the counters. Examination of purity of the gas is carried out by means of an external Cs137 source. In case the gas shows bad plateau characteristics, it is converted by a new process into ethane, using H2 and a palladium catalyst. Thereby, the plateau characteristics improve considerably. The 50%-voltage then is 200 v lower, the slope of the plateau only amounts to 0.2 %/100 v (with external source), and the plateau length increases from 600 v to 1200 v. The additional work amounts to 1/2 hour.

Both dendrochronology and radiocarbon (14C) dating have their roots back in the early to mid-1900s. Although they were independently developed, they began to intertwine in the 1950s when the founder of dendrochronology, A. E. Douglass, provided dated wood samples for Willard Libby to test his emerging 14C methods. Since this early connection, absolutely dated tree-rings have been key to calibration of the Holocene portion of the 14C timescale. In turn, 14C dating of non-calendar-dated tree-rings has served to place those samples more precisely in time, advance development of long tree-ring chronologies, and bring higher resolution to earlier portions of the 14C calibration curve. Together these methods continue to shape and improve chronological frameworks across the globe, answering questions in archaeology, history, paleoclimatology, geochronology, and ocean, atmosphere, and solar sciences.

Routine radiocarbon analyses were last reported for the Laboratory of Isotope Geochemistry at the University of Arizona in 1971 (Haynes, Grey, and Long, 1971), and a special date list on packrat middens appeared in 1978 (Mead, Thompson, and Long, 1978). This list presents results obtained from our gas proportional counting facility before its major renovation and before the addition of a liquid scintillation counting system. The characteristics of these new systems will be described in the next date list.

The radiocarbon dating laboratory at the Smithsonian Institution, Division of Radiation and Organisms, was established in September 1962. After careful calibration with known samples and refinements in the methane synthesis system, routine analysis of samples was begun in the spring of 1963.

Two simple algorithms are suggested here to correct for the effect of diffusion and diagenetic sulfate reduction on radiocarbon age determination of marine porewater. The correction algorithms were developed from mass balances of sulfate, dissolved inorganic carbon (DIC), and 14C of the DIC (14CDIC) in vertical concentrations profiles in porewater starting from the sediment water interface. The algorithms were tested on data collected during our recent study of sediment porewaters extracted from the deep Eastern Mediterranean. The real ages of these porewaters varied from present (top of the core) to approximately 30 ka BP (bottom of the core) covering most of the dynamic range of the 14C method (approximately 5 half lives). These ages were markedly older than the ages calculated from 14CDIC analyses by the regular age equation.

It is clearly demonstrated that in this case the correction of the apparent age for diffusion across the sediment/water interface is overwhelmingly larger than the correction for the effect of sulfate reduction. The correction for the effect of 14C diffusion alone results in a perfect match between the calculated apparent 14C ages and the real ages of porewater and therefore is the preferred algorithm for correcting apparent ages of porewater.

This study addresses the development of an absolute chronology for prominent burial sites of Inner Asian nomadic cultures. We investigate Saka archaeological wood from a well-known gold-filled Baigetobe kurgan (burial mound #1 of Shilikty-3 cemetery) to estimate its calendar age using tree-ring and 14C dating. The Saka was the southernmost tribal group of Asian Scythians, who roamed Central Asia during the 1st millennium BC (Iron Age). The Shilikty is a large burial site located in the Altai Mountains along the border between Kazakhstan and China. We present a new floating tree-ring chronology of larch and five new 14C dates from the construction timbers of the Baigetobe kurgan. The results of Bayesian modeling suggest the age of studied timbers is ~730–690 cal BC. This places the kurgan in early Scythian time and authenticates a previously suggested age of the Baigetobe gold collection between the 8th and 7th centuries BC derived from the typology of grave goods and burial rites. Chronologically and stylistically, the Scythian Animal Style gold from the Baigetobe kurgan is closer to Early Scythians in the North Caucasus and Tuva than to the local Saka occurrences in the Kazakh Altai. Our dating results indicate that the Baigetobe kurgan was nearly contemporaneous to the Arjan-2 kurgan (Tuva) and could be one of the earliest kurgans of the Saka-Scythian elite in Central Asia.

A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. We compared the time it took to complete the procedure and the amount of sample material remaining. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. We also observed a darker discoloration of the KOH solutions, indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method.

The Indonesian Arc represents the subduction of the Indian-Australian plate beneath Asia. It has been the scene of catastrophic tectonic activity, including the recent 2004 M=9.1 Aceh earthquake and resulting Indian Ocean tsunami. We have dated planktonic forams associated with historic tephras (Tambora, 1815 and Krakatau, 1883) in marine sediment cores to determine radiocarbon reservoir ages for 2 locations along the arc. Our best estimates for 19th century regional reservoir corrections (ΔR) are +90 ± 40 yr for surface-dwelling species and +220 ± 40 yr for mixed planktic assemblages containing some upper thermocline species, but scatter in the data suggests that past surface reservoir ages may have varied by about ±100 yr. We used the results of this study to investigate a proposed very large AD 535 eruption at or near Krakatau. We find no evidence for ash from such an eruption, and although this is negative evidence, we consider it sufficiently strong to rule out any possibility that one took place.

Alpine glaciers are valuable archives for the reconstruction of human impact on the environment. Besides dating purposes, measurement of radiocarbon (14C) content provides a powerful tool for long-term source apportionment studies on the carbonaceous aerosols incorporated in ice cores. In this work, we present an extraction system for 14C analyses of dissolved organic carbon (DOC) in ice cores. The setup can process ice samples of up to 350 g mass and offers ultra-clean working conditions for all extraction steps. A photo-oxidation method is applied by means of external UV irradiation of the sample. For an irradiation time of 30 min with catalyzation by addition of Fe2+ and H2O2, we achieve an efficiency of 96 ± 6% on average. Inert gas working conditions and stringent decontamination procedures enable a low overall blank of 1.9 ± 1.6 μg C with a F14C value of 0.68 ± 0.13. This makes it possible to analyze the DOC in ice samples with a carbon content of as low as 25 μg C kg−1 ice. For a first validation, the new method was applied to ice core samples from the Swiss Alps. The average DOC concentration and F14C values for the Fiescherhorn ice core samples show good agreement with previously reported data for the investigated period of 1925–1936 AD.

The C14 dates given below are a continuationof the work presented in our previous list (RIKENII), and have been obtained by countingCO2 at ca. 2 atm pressure in a 2.7 Lstainless steel counter. Results obtained during1966 are described.

Atmospheric carbonaceous aerosol is traditionally divided into organic carbon (OC) and elemental carbon (EC). Their respective carbon amounts are usually analyzed by means of an OC/EC analyzer and their fossil and non-fossil origins can be determined by radiocarbon analysis, which has proven to be a powerful tool for carbonaceous aerosol source apportionment. Thus far, separation of OC and EC has been performed off-line by manual and time-consuming techniques. We present an on-line system that couples a commercial OC/EC analyzer with the gas ion source of the accelerator mass spectrometer (AMS) MICADAS and its CO2 feeding system. The performance achieved with reference materials and blanks are discussed to demonstrate the potential of this coupling for source apportionment of atmospheric carbonaceous particulate matter.

This list reports 14C measurements completed between August 1973 and November 1975. Other projects completed in that period will be reported later. Age calculations are based on 14C half-life of 5568 yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background, and modern, and are ± 1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted, 12C/13C measurements were not made and results are not corrected for 13C fractionation. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed: a Packard Tri-Carb Model 3002, and 2 Beckman LS-230 spectrometers obtained through a grant from the National Science Foundation.