The AMS 14C dating of Iron Age rice chaff ceramic temper from Ban Non Wat,Thailand: First results and its interpretation

Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS ¹⁴C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2–0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other ¹⁴C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region.     

14C dating of small archaeological samples: neolithic to iron age in the central alpine region

Accelerator mass spectrometry (AMS) radiocarbon ¹⁴C dating will widen enormously the range and scope of archaeological investigations. This is due mainly to 100- to 1000-fold sample size reduction over conventional dating. In order to determine the size and the quality of samples that can be accepted for AMS ¹⁴C dating, we have selected archaeological samples relating to the Neolithic to Iron Age. The basis of our AMS target preparations is the coking (pyrolysis) of organic matter after elimination of impurities by various physical and chemical treatments. The effect of the morphology as well as of the grain size distribution of the charcoal particles was determined in order to achieve optimal conditions for accelerator dating.     

The hardwater effect in AMS 14C dating of food crusts on pottery

The pottery investigated in this study comes from late mesolithic inland sites next to rivers in Northern Germany. The first AMS ¹⁴C datings of food crusts from these sites showed surprisingly high ages, which could be caused by the hardwater effect.Modern samples from the rivers have ages of several hundred ¹⁴C years, and a modern food crust prepared from fish with a certain reservoir age shows the same age as the fish. Surprisingly, there was a large age difference between water samples and fish/mollusc shell from the same river. Associated archaeological samples of terrestrial and fluvial origin show age differences of several hundred and up to 3000 years. These high age differences are only to a limited extent transferred to the archaeological food crusts.     

Characterization of pre-Hispanic pottery from Teotihuacan, Mexico, by a combined PIXE–RBS and XRD analysis

A combined analysis of IBA techniques (Proton Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectroscopy (RBS)) and a complementary study by X-ray Diffraction (XRD) were performed to characterize pottery corresponding to the Epiclassic period (A.D. 700–900) from Teotihuacan, Mexico. Elemental compositions of pottery samples were measured by simultaneous PIXE and RBS using 2.6 MeV protons. Red, white and brown pottery pigments were studied by non-vacuum PIXE and a proton beam of 3 MeV. The various mineralogical phases of the pottery were identified by XRD. From pottery elemental compositions and its mineralogical phases, some differences among the pottery samples and groups were established.     

沉积环境地球化学变化对牙齿ESR-U系联合法测年的影响

在进行考古测年时,沉积环境的地球化学变化可能会影响野外环境剂量率的测定,从而导致基于辐射暴露原理的测年方法结果的不准确性,如释光和电子自旋共振(ESR).实验通过对采自法国南部Arago洞穴中三种不同沉积环境下的同层牙齿样品进行ESR-U系联合法年代学分析,探讨了不同沉积环境及沉积环境的不均一性对测年结果产生的影响.其中出自石英矿物环境的样品年龄约为330 ka,而另两种不同沉积环境(碳酸盐和磷酸盐)下的样品年龄约480 ka,前者比后者年轻约150 Ka,这一现象可能是由于对石英矿物环境样品野外环境剂量率的高估造成的.     

前剂量饱和指数法测定中国瓷器年代

用前剂量饱和指数法测定了23件中国瓷器的年代,结果表明,热释光年代与考古年代在一个标准偏差为27％以内的一致性非常良好,这样的误差在瓷器的年代测定中是可以接受的。     

前剂量法断代的自动化测量

用ＲＩＳＯ ＴＬ－ＯＳＬ仪进行了年轻陶器样品的前剂量法自动化测龄。对明代陶器的断代结果与细颗粒－添加剂量法结果相比符合率达１００％；鉴别古陶膺品也准确可靠。     

Radiocarbon dating and wiggle matching of wooden poles forming circular structures in the 1st Millennium BC at the Mawaki archaeological site,central Japan

Wooden circular structures, presumed archaeologically as a structure related with ritual of ancient people in the Final Jomon period, are specific to archaeological sites excavated mainly in the coastal region around Noto peninsula, central Japan. So far, only few attempts have been made at chronological studies on these wooden structures. ¹⁴C dating has been attempted to wooden poles forming the structures, which had been excavated at the Mawaki archaeological site, Ishikawa prefecture, central Japan, to examine construction period of the structures. It was revealed that these structures were constructed in the Final Jomon period, most probably within 900–400 cal BC. In addition, we have tried wiggle matching of ¹⁴C ages for several annual rings separated from three and two poles that were constituting two circular structures, the oldest and the newest ones. ¹⁴C dates of annual rings measured with AMS were wiggle-matched to IntCal04 data sets by Bayesian statistics. The results indicated that the construction period of these wooden structures can be placed within ca. 820–680 cal BC, being narrowed by about 350 calendar years successfully.     

Radiocarbon dating of microgram samples: Accelerator mass spectrometry and electromagnetic isotope separation

An exploratory experiment was performed to investigate methods for extending the direct atom counting technique to natural radiocarbon samples containing only micrograms of carbon. A threefold approach was adopted for the study: direct measurement of a microgram-size sample, in the form of elemental carbon; dilution of a few micrograms of an environmental (atmospheric particulate) reference sample with inert (“dead”) carbon; and implantation of carbon ions (as CO⁺) into copper foil prior to placement in the tandem accelerator ion source. The last experiment, which linked work with the NBS variable-geometry electromagnetic isotope separator and the NSRL tandem Van de Graaff, automatically led to isotopic enrichment during the implantation step. All three phases of the experiment were unique (not previously attempted) and gave consistent results, indicating great promise for the future application of direct atom counting to individual trace chemical species of environmental or archaeological importance. The directly measured sample of elemental carbon was prepared from the new ¹⁴C dating standard, and it yielded a result having an imprecision of 3% where ions were counted for about 15 min using less than 40 μg carbon in the tandem ion source.     

偃师商城宫城建筑基址夯土的光释光测年初步研究

用光释光测年技术对河南偃师商城宫城部分宫殿和围墙基址夯土进行了定年。在夯土基址的建造过程中，有些石英颗粒可能见光而使其光释光信号被释放回零，光释光‘时钟’重新开始计时。本文用单片再生剂量法测夯土中粗颗粒石英的等效剂量，测得的等效剂量值的分布说明石英颗粒的光释光信号在基址建造过程中有不同程度的晒退。据晒退相对彻底的石英颗粒得出的夯土光释光年龄分别是4.0ka、2.2ka和2.5ka。尽管这些年龄值与考古年龄存在差异，但表明用光释法测年技术对宫殿建筑基址夯土进行定年是可行的。     

陶器细粒混合矿物的前剂量年代测定

提出将陶器细粒混合矿物法直接用于前剂年代测定，这个方法的优点是采用“一次激活技术”和不需要作热激活特性试验，从而避免了因加热引起的激活特性变化。本方法已应用在古代陶器的真伪鉴定上，结果表明，对那些年龄很轻或高温热释光性能不好的样品，本方法能发挥其特殊的作用。     

A compositional study of a museum jewellery collection (7th–1st BC) by means of a portable XRF spectrometer

Within the framework of the project “Jewelmed” (ICA3-1999-10020), the chemical composition of 34 gold and four silver jewels was examined. These jewels belong to the Benaki museum's collection in Athens, Greece and are dating from the 7th to the 1st century BC. The compositional analysis of the jewels was performed by means of a “home-made” portable X-ray fluorescence (XRF) spectrometer. The XRF results have shown that the gold jewels can be categorized in two groups, which include artifacts made by native and by high purity gold, respectively. For the silver jewels the results have provided interesting information regarding the manufacturing technology, the authenticity of the jewels and the raw materials used. The potential and the limitations of the XRF technique, applied in the chemical analysis of archaeological metal artifacts, are also discussed.     

陶粉样品的光晒退实验研究

本文绘出了用红、黄和白炽等普通灯泡以及荧光灯做的陶粉样品的光晒退实验结果;分析了光晒退与光强和光谱分布的关系。     

Nanoparticles of Al2O3:Cr as a sensitive thermoluminescent material for high exposures of gamma rays irradiations

Aluminum Oxide (Al₂O₃) doped with proper activators is a highly sensitive phosphor commonly used for radiation dosimetry using thermoluminescence (TL) technique. Nanoparticles of this material activated with Chromium (Cr) have been synthesized using the propellant chemical combustion technique and studied for their TL response. They were characterized by X-ray diffraction and scanning electron microscope. The synthesized material has spherical nanoparticles with grain size around 25 nm. These nanoparticles were exposed to heavy doses from γ-rays of ¹³⁷Cs. The TL glow curves show a prominent peak at around 474 K. This peak is found to be sensitive for high exposures of γ-rays and has linear response in the range of 100 Gy-20 kGy without showing saturation. This remarkable result suggests that Al₂O₃:Cr nanoparticles might be used for the dosimetry of food and seed irradiations.     

内蒙古大青山南麓古土壤14C测年研究

对采自内蒙古自治区土默特左旗上达赖村附近的大青山南麓山前断裂带上5个钙质古土壤样品和1个陶片样，分别用NaOH溶液将古土壤样品分离出胡敏酸、胡敏素和古土壤全碳以及无机碳酸盐等不同组分，对这些组分进行^14C年代测定，同时对陶片进行热释光的年龄测定，以探讨古土壤的中不同组分的HC测年可靠性。     

“非剂量”热释光断代

本文叙述了一个“非剂量”热释光断代方法。在这个方法中,总热释光和年热释光分别用考古样品中的天然矿物和人造热释光材料测定,并用热释光直接估算年龄。用本方法测定了28个考古样品,结果表明,这些年龄与用剂量法测得的热释光年龄一致,并具有误差降低和不需要刻度放射源的优点。     

EDXRF analysis of Marajoara pubic covers

This work evaluated the elemental composition of decorated pottery pubic covers (tangas) from the Marajoara culture of Marajó Island (at the mouth of the Amazon River, Brazil) using EDXRF technique. The XRF system used in this work consists in a Si(Li) detector from ORTEC, with resolution of 180 eV, at 5.9 keV, and a mini X-ray tube with Mo anode. The elements identified in the samples were: S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Ga, Rb, Sr, Y, Zr and Pb. Principal components analysis (PCA) was used to evaluated the provenance of the samples.