The chief objective of this paper is to improve our understanding of the Neolithic in Eastern Hungary using absolute chronological data. To accomplish this we calibrated new measurements as well as previously published dates. The up-to-date, standardized evaluation of 261 calibrated measurements showed temporal overlaps between archaeological cultures defined on the basis of ceramic styles. The increasing number of dates suggest that the Neolithic period began at the turn of the 6th and 7th millennia bc and lasted for ca. 1500 yr in the present area of the Great Hungarian Plain (Alföld). Further research should be aimed at complementing the current data set with dates from western Hungary and establishing additional correlations among stratigraphic, typological and radiocarbon dates.

The activity of radiocarbon in 14CO2 and 14CnHm chemical forms is measured in the vicinity of Paks nuclear power plant (NPP), Hungary, by sampling environmental air. Four differential sampling units at different sites collected samples less than 2 km away from the 100-m-high stacks of Paks NPP, and for reference a sampler was operated at a station ∼30 km away from Paks NPP. We present the results of continuous observations at the 5 stations covering the time span from 2000 to 2005. The samples have been analyzed by a proportional counting technique. During a cleaning tank incident at unit 2 of Paks NPP in April 2003, a significant release of radioactive isotopes took place from the damaged fuel assemblies, and gaseous products escaped through the chimney. We evaluate the possible short- and long-term impact of this incident on the 14C content of the atmosphere in the surroundings of Paks NPP. Comparing our 14CO2 measurements with data sets from Jungfraujoch and Schauinsland, as well as from Košetice (Czech Republic), we demonstrate that the incident had no definite influence on the 14C content of the atmosphere.

Two 2 m long ice cores (BA and BB) were extracted from the floor ice of Borştig Ice Cave in December 2005. Below a co-existing dust horizon (~13 cm underneath the 10 December 2005 ice surface) neither core presented any sign of hiatus, so the ice deposition is considered to be continuous. Tritium concentration of 94 samples from a 1.85 m long ice section were analysed by liquid scintillation counting technique. Samples from the lower 0.33 m of the sequence did not contain tritium above the critical level (7.2 TU). The highest value of tritium content (166.4±4.0 TU) was found at ~96 cm below the surface. This salient value is considered to be synchronous with the climax of tritium concentration in the Northern Hemisphere's atmospheric precipitation (1963). Beside this characteristic global radiochemical marker event, minor events were also detected, and dated (ie, 1954, 1958 and 1975) by corresponding peaks in the tritium concentration record of BB ice core to peaks of an estimation of tritium activity of past precipitation at Borştig Ice Cave location. The estimation was based on a data set from four nearby stations of the Global Network of Isotopes in Precipitation. The highest annual accumulation rate (6.74 cm/yr) was between 1958 and 1963 and gradually decreased to 0.54 cm/yr for the recent decades. The mean ice accumulation rate was 4.34 cm/yr over the 1954—1986 period. The estimated age at the bottom of the 21 m thick ice block assuming constant accumulation is roughly 500 years.

Approximately 10% of Hungary is covered by dust sequences of the Quaternary period. Samples have been taken from more than 50 outcrops and boreholes during fieldwork in the past 20 yr. Some 81 bulk samples taken from 27 profiles of the Hungarian loess regions have been analyzed for radiocarbon. Based on the 14C results, loess layers that accumulated between 33,000 and 12,000 BP were selected for further investigation. The sedimentation rates of the 27 loess profiles suggest periods of slow and quick dust accumulation in the Carpathian Basin during the Upper Weichselian period. It seems to us that some soil development and intense weathering periods interrupted the loess development during the Upper Weichselian in Hungary. According to the 14C dates, the estimated average rate of sedimentation was 0.31 mm/yr in both the northern and southern parts of the Carpathian Basin between 33,000 and 12,000 BP.

ABSTRACT.A high-precision atmospheric CO 2 monitoring station was developed as a field unit. Within this, an integrating CO 2 sampling system was applied to collect samples for radiocarbon measurements. One sampler was installed in the second largest city of Hungary (Debrecen station) and 2 independent 14 CO 2 sampling lines were installed ~300 km from Debrecen in a rural site at Hegyhátsál station as independent background references, where high-precision atmospheric CO 2 mixing ratios have been measured since 1994. Fossil fuel CO 2 content in the air of the large Hungarian city of Debrecen was determined during the winter of 2008 using both the measurements of CO 2 mixing ratio and 14 C content of air. Fossil fuel CO 2 was significantly enhanced at Debrecen relative to the clean-air site at Hegyhátsál.

ABSTRACT. We present our new graphite target production system, developed in the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), for accelerator mass spectrometry (AMS) radiocarbon dating measurements. The system consists of a gas handling line and a graphite target production system. Results of AMS measurements, stable isotope mass spectrometry measurements, and gravimetric/pressure yield determinations have been used to find the proper conditions for the graphitization process. We have also investigated the 14 C contamination and the memory effect of the system during the graphitization processes. This paper covers the details of these experiments and a discussion of the results.

ABSTRACT. Fossil CO 2 emissions have been diluting the global 14 C/C ratio of atmospheric CO 2 (Suess effect). We estimated the 14 CO 2 amount in the atmosphere (and its trend) utilizing the calculated 14 CO 2 activity concentration in the atmosphere (a acn , reported in mBq m -3 ). This parameter, calculated from  14 CO 2 and the CO 2 mixing ratio (reported in micromoles of CO 2 per mole of air), is connected with the 14 CO 2 quantity in the volume or mass unit of air, which is not influenced by the Suess effect. This parameter can only be influenced by processes linked to 14 CO 2 emissions/uptake, e.g. associated with atmosphere-biosphere or atmosphere-ocean CO 2 exchange as well as by anthropogenic emissions of 14 CO 2 . Results obtained from measurements at Schauinsland station, Germany, indicate a stable amount of 14 CO 2 in the atmosphere since the early 1990s.

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