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The atmospheric tests of nuclear weapons caused a sudden increase in the radiocarbon concentration in the atmosphere from 1955, reaching its maximum value in 1963-1965. Once the nuclear tests in the atmosphere were halted, the C concentration started to decrease. This behavior of the radiocarbon concentration is called the 'Bomb Peak', and it has successfully been used as a tool for high-precision radiocarbon measurements, in forensic sciences and biology. In the art field, the possibility of dating canvas, wood and paper, widely used as supports for paintings, may be an invaluable tool in modern art studies. [ABSTRACT FROM AUTHOR]

The issue of contamination in radiocarbon dating is well known and can affect not only archaeological findings but also artworks. In the latter case, a possible source of contamination is represented by the products used during the restoration, e.g. resins of synthetic origin like the well-known Paraloid, applied to wood artifacts as a strengthening and preserving agent. In the case of incomplete removal prior to dating, the resins produce an apparent aging of the samples. Mechanical cleaning using traditional tools and the standard pretreatment acid-base-acid (ABA) protocol are not sufficient to remove such contaminants, while the use of organic solvents, in particular petroleum solvents and chlorine-based products, can be effective. However, the most widely used protocol, based on the Soxhlet extraction system, is very time consuming. Here, in the presence of chloroform-soluble applied products, like the widespread Paraloid B-72, this study proposes the use of a new easily operated pretreatment procedure, developed at INFN-LABEC in Florence, based on the use of chloroform (CHCl3) as solvent and on a simple extraction. First, the effectiveness of this procedure was checked by applying it to remove the resin from wood samples of known age, which had been previously intentionally contaminated by applying large quantities of Paraloid. 14C AMS measurements performed on the test samples before and after contamination and application of the proposed procedure proved its effectiveness for removal, while this was not the case when applying standard ABA protocols. Fourier transform infrared (FTIR) spectroscopy analyses also were used to check the removal of contaminants. The new procedure was applied in two case studies: the wood frame of an altar piece from the Renaissance and a painting on canvas from the early 20th century. For both artworks, the use of synthetic resins was documented in restorations performed a relatively long time ago: the wood frame was restored using just Paraloid, the canvas using a thermoplastic polymer soluble in chloroform. Enough time elapsed for the resins to create cross-linking bonds with the original material. Despite this, the results obtained by 14C AMS dating confirm the reliability of the new chloroform-based pretreatment in removing the contaminations. Also in these cases, spectroscopic techniques were used to compare the effectiveness of the ABA and the new treatments in removing the contaminants. [ABSTRACT FROM AUTHOR]

Since installation of the new accelerator at INFN-LABEC in Florence in 2004, the workload has progressively increased in the radiocarbon dating laboratory, requiring a faster sample preparation throughput and greater versatility to allow for a larger variety of treated materials. The "standard" sample preparation line is based on an elemental analyzer (EA) for the combustion of the pretreated samples, and a vacuum line where the CO2 is collected and then converted to graphite. This line has been recently redesigned while maintaining the EA, since this instrument provides us reliable and fast sample combustion and separation of gases. The volumes were optimized and all the mechanical parts (e.g. the fittings) were changed in order to improve the vacuum level, thus decreasing the possibility of contamination; finally, the number of graphitization reactors was doubled (from 4 to 8). In those rare cases involving samples characterized by a complex nearly graphitic structure (e.g. burnt residues), the EA might not guarantee a complete combustion. For these samples, we successfully tested the new sample preparation line that has been recently installed at LABEC and especially dedicated to aerosol samples. This line is equipped with a custom-made combustion oven able to heat to 1000 °C. The subsequent gas separation is accomplished by chemical and thermal traps. As an example, the dating of organic matter collected from an Etruscan bronze statue will be presented and discussed. [ABSTRACT FROM AUTHOR]

Radiocarbon dating of bones can be very useful in archaeological contexts, especially when dealing with funerary deposits lacking material culture, e.g. pottery vessels. 14C measurements of bone samples are usually performed on the extracted collagen residue. The content and the quality of collagen can vary significantly, mainly depending on bone preservation and diagenesis. Generally speaking, environmental conditions such as low pH level of soils, high temperatures, and percolating groundwaters, typical of arid and tropical zones, can affect the preservation of collagen; at the same time, bones recovered in such environments are more likely to be contaminated with carbon from the surrounding environment. Possible contamination of samples can also occur in temperate zones. While low collagen content is a condition we cannot overcome, we can use several chemical and elemental indicators in order to assess collagen quality. Among these, the C/N atomic ratio is considered a good parameter for detecting low-quality collagen and possibly contaminated samples. In a combustion and graphitization setup like that installed at INFN-LABEC, Florence, measurement can be easily performed using an elemental analyzer when combusting the sample prior to graphitization, thus requiring no extra effort (or extra amount of sample) during the preparation procedure. Bone samples recently 14C dated at INFN-LABEC have confirmed that the measurement of C/N atomic ratios can give some indications of the collagen quality. The bone material was collected from 3 necropoles of the Bronze Age period in Cyprus (Erimi-Laonin tou Porakou, Lophou-Kolaouzou, and Erimi-Kafkalla&Pitharka, along the Kouris Valley), an area characterized by environmental conditions that do not favor bone preservation. Samples were treated to extract collagen and measured by accelerator mass spectrometry (AMS). 14C results have been compared with the archaeological evidence, showing some relationship between measured C/N atomic ratios and collagen quality. In particular, when grouping the measured samples according to their C/N ratio, the agreement between 14C dates and archaeological evidence is good or inconsistent when the C/N ratio clearly falls inside or outside the "recommended" range, respectively, with a still reasonable agreement also when it is slightly above the upper limit of that range. [ABSTRACT FROM AUTHOR]

The site area of Erimi-Laonin tou Porakou (Limassol, Cyprus) has been surveyed and systematically excavated since 2007 as a joint research project of the University of Florence and the Department of Antiquities of Cyprus. A focused investigation was dedicated to analyzing funerary evidence from the southern Cemetery (Area E), where 7 singlechamber graves were excavated. The offering goods assemblages from the burials point to a general date ranging from Early to Late Bronze Age I, and draw a sequence of use that is contemporary to the stratigraphic deposits from the top mound Workshop Complex (Area A). During the 2010 field season, charcoal samples from the Workshop Complex and bone samples from the skeleton remains of 2 burials (tombs 228, 230) were opportunely taken for radiocarbon analyses. 14C dating was performed at the AMS-IBA Tandetron accelerator of the INFN-LABEC Laboratory in Florence. This paper will discuss the results of the 14C analyses and compare them with the archaeological evidence in order to outline a chronological sequence for the settlement and cemetery areas at Erimi-Laonin tou Porakou, thus collecting further data on the development and pattern of occupation of the Early to Late Cypriote period in the Kourion area. [ABSTRACT FROM AUTHOR]