THE COMPLEMENTARY USE OF NEUTRONS AND X‐RAYS FOR THE NON‐DESTRUCTIVE INVESTIGATION OF ARCHAEOLOGICAL OBJECTS FROM SWISS COLLECTIONS*

This paper shows the possibilities offered by the combined use of non‐destructive neutron and X‐ray beams in archaeological research on metallic finds. The following five artefacts from Swiss excavations were submitted to investigation, each with dedicated aims: a Roman sword, a Roman dagger, an Iron Age bucket, Iron Age spearheads and a Roman finger ring. The images obtained with both methods—neutrons and X‐rays—are discussed in length in this paper. The investigations took place at the Paul Scherrer Institute and the archaeologists who studied the objects come from the Universities of Lausanne and Zurich.     

Beyond the Visible: Combined Neutron and X‐ray Imaging of an Altar Stone from the Former Augustinian Church in Fribourg,Switzerland

An altar table from the former Augustinian church in Fribourg (Switzerland) was studied by means of neutron and X‐ray imaging to investigate the embedded reliquary. The neutron transmission images showed that the sepulcrum contained three objects showing high contrast and high attenuation. As the particles were almost invisible in the X‐ray image, it was assumed that they were organic material. Comparative measurements on reference samples of materials possibly contained in such a reliquary (bone, teeth, leather, incense and parchment) suggest that the particles are bone fragments. Besides an assessment of the content, the results from the neutron investigation allowed a proposal of the probable geometry (i.e., shape and dimensions) of the sepulcrum.     

NEUTRON TOMOGRAPHY AS A VALUABLE TOOL FOR THE NON‐DESTRUCTIVE ANALYSIS OF HISTORICAL BRONZE SCULPTURES

This paper explains, with the example of a Roman object (the ‘Mars from Oberweningen’, Switzerland), why neutrons can be used preferentially for the non‐destructive analysis of metallic objects of relatively large size. This method is superior to the conventional X‐ray tomography method due to the higher penetration ability in metals such as copper, tin and even lead. With this method, differing materials can also easily be differentiated. In this way, the inner and outer structures of objects can be observed with the help of tools based on mathematical algorithms. Slices at arbitrary positions and segmentation of different material clusters aid the understanding of manufacturing processes and can describe the present preservation status. This helps in selecting optimal and additional conservation measures in museums for further preservation. Beside the qualitative overview on structure and inner properties of the objects, quantitative information can be derived about material content and composition. This method and the subsequently needed facilities for this method are available at PSI for similar studies on demand.     

Recycled Blessings: An Investigative Case Study of a Rewrapped Egyptian Votive Mummy Using Novel and Established 3D Imaging Techniques

This case study was the first of its kind, where neutron computed tomography (CT) was applied to a wrapped mummified animal. Conventional X‐ray CT was also used to allow for meaningful comparison, and complementary data for a comprehensive investigation. Previous applications of both techniques are limited to metallic objects, such as bronze Buddhas. The mummy used in this study (IA.2402) is dated between the Third Intermediate Period (1069–664 bce ) to Late Period (664–332 bce ) according to the wrapping style, and was originally believed to contain a complete skeleton of a feline. However, precise date and provenance were unknown. Our results prove the presence of only partial juvenile feline remains, and provide a date range for artefact creation (900–804 bce ± 30) and alteration (367–204 bce ± 30). Therefore, this study implements an established imaging technique (neutron CT) in a novel way, while preserving and conserving the intrinsic value of the artefact through non‐destructive investigation.     

Eighteenth‐Century Meissen Porcelain Reference Data Obtained By Proton‐Beam Analysis (PIXE–PIGE)

Prior to their restoration, the porcelain bodies of broken pieces from 31 authentic Meissen objects of the early 18th century were investigated by proton‐beam analysis. Attention was paid so that the proton beam probed only the bare porcelain paste areas of fractures. Thus, contributions to the measured X‐ray and γ‐ray spectra from adjacent surface glaze were prevented. The chemical compositions, obtained by simultaneous detection of elements with Z ≥ 13 (X‐rays) and lighter elements Z ≤ 14 (γ‐rays), represent rather consistent mixtures of paste ingredients. This result highlights the durable recipes and raw materials used in early Meissen porcelain production in the years 1725–50. Mean concentration values of element oxides, deduced from the detailed measurements, prove suitable for use as a database for Meissen porcelain paste identification. Material authentication of intact objects, without access to the bare porcelain body, is demonstrated by inspection of the white glaze. Unique museum objects are examined in atmosphere and without sampling. A low proton‐beam intensity and a short irradiation time ensure non‐destructive analysis. Simultaneous radiation and backscattered particle detection allow complete composition analysis, using the established ion beam techniques of particle‐induced X‐ray emission (PIXE), particle‐induced gamma‐ray emission (PIGE) and Rutherford backscattering spectrometry (RBS).     

NEUTRON RESONANCE CAPTURE ANALYSIS OF SOME GENUINE AND FAKE ETRUSCAN COPPER ALLOY STATUETTES*

The probability of nuclei capturing neutrons reveals sharp peaks, so‐called ‘resonances’, which occur at neutron energies that are specific for each element. These resonances are very suitable for analysing the elemental composition of objects. They are the basis of a new analytical method, ‘neutron resonance capture analysis’ (NRCA). This is a fully non‐destructive method, which is applicable to almost all stable isotopes, determines the bulk elemental composition, does not require any sample preparation and results in a negligible residual activity. Recently, NRCA has been applied in a study of a series of bronze statuettes, obtained from the National Museum of Antiquity in Leiden (NL).     

Non-destructive Phase Analysis of Archaeological Ceramics using TOF Neutron Diffraction

Mineral phase analysis of ancient ceramics carried out by neutron diffraction yields complementary information to X-ray diffraction analysis. Since neutrons are highly penetrating, neutron diffraction in general allows non-destructive investigations of bulk samples rather than of surface layers or powdered material. This means complete, intact specimens can be studied. A time-of-flight (TOF) neutron diffractometer offers additional advantages considering experimental set-up, accommodation of large objects and data collection times. First test measurements with respect to archaeometric applications have been performed on different fragments of medieval Rhenish pottery using the TOF neutron diffractometer ROTAX at the spallation source ISIS, U.K. Phase fractions obtained from a Rhenish stoneware jar fragment compare well with those from a powder sample prepared from the same fragment. This finding indicates that reliable results can be obtained by illuminating a large piece or even a complete ceramic object without causing damage.     

The production and technology of glazed ceramics from the middle ages,found in the saepinum territory (Italy): a multimethodic approach*

A collection of ceramics from the Middle Ages found in Altilia and Terravecchia (the Saepinum area, Campobasso, Italy) were characterized by using different mineralogical analyses to investigate their provenance and production techniques. The body ceramic was investigated using Rietveld phase analysis of X‐ray powder diffraction patterns, X‐ray fluorescence spectrometry and scanning electron microscopy. The chemical compositions of the coatings were measured by scanning electron microscopy and their mineralogical compositions were determined using a particular technique of X‐ray small‐angle scattering (SAS) optimized for studies of thin films. Moreover, the material used for decoration was studied using micro‐Raman spectroscopy. The archaeometric results confirmed the distinction into two different ceramic classes, already individuated from archaeological analysis: the Altilia objects belong to the protomajolica class, whereas the objects from Terravecchia are RMR (ramina‐manganese‐red) ceramics. A comparison between the chemical and mineralogical compositions of good‐quality ceramic objects and those of waste products indicated local production of the ceramics. A sharp distinction was found in the chemical composition of the coatings: the Altilia products have tin‐opacified lead glazes, while the Terravecchia ones have transparent high‐lead glazes. Among the Altilia products, the unsuccessful process that produced a large quantity of discarded materials was attributed to the high lead content of the glazes. In fact, the principal advantage of the high lead content was to make the preparation and application of the glaze suspension easier, but the risk of reduction of lead oxide to metallic lead was greatly increased. Using micro‐Raman spectroscopy, the following minerals were identified as pigments: pyrolusite for the dark colour, malachite for green, lepidocrocite for yellow and hematite for red.     

The Use of Optical Coherence Tomography for Monitoring the Subsurface Morphologies of Archaic Jades

We demonstrate the use of the Optical Coherence Tomography (OCT) technique for non‐invasive scanning of the subsurface morphologies of jade objects. The two‐dimensional tomography images show the refractive index or dielectric constant variations in the samples, reflecting their structures. Three samples of archaic jade objects from the Qijia and Liangzhu cultures in China are scanned in order to understand the subsurface morphologies of the naturally whitened jades. Also, two jade objects with artificial treatments (burning) are scanned and compared with the original materials in subsurface structures. In the original objects, the jade materials can generally be quite transparent, such that the backscattering intensity is weak, although the large‐scale (tens of microns or larger) subsurface morphology can be clearly observed. After burning, small‐scale (smaller than a few microns) structures are formed and the backscattering intensity is enhanced. In this situation, the large‐scale structures may be preserved or even newly generated. On the other hand, in an archaic object with natural whitening, small‐scale structures are also formed. Hence, the deeper distributions of significant backscattering intensity are observed, when compared with the unwhitened objects. Nevertheless, the large‐scale features diminish during the whitening process. With OCT scanning, such differences in subsurface morphology can provide us a valuable reference for authenticating archaic jade objects.     

FIELD AND LABORATORY MULTI‐TECHNIQUE ANALYSIS OF PIGMENTS AND ORGANIC PAINTING MEDIA FROM AN EGYPTIAN COFFIN (26TH DYNASTY)

This paper describes the physico‐chemical analyses performed on an Egyptian wood coffin on the occasion of its restoration in the hall of the National Archaeological Museum of Parma (Italy), with the aim of investigating the pigments and organic materials originally used. Pigment determination was performed both in situ by a portable energy‐dispersive X‐ray fluorescence (EDXRF) spectrometer and in the laboratory using a micro‐Fourier‐transform‐infrared (micro‐FTIR) and a Fourier‐transform (FT) Raman spectrometer. The identification of organic materials was performed through gas chromatography – mass spectrometry (GC–MS) and micro‐FTIR analysis. Amongst the pigments, special attention was paid to the green, which appeared to be severely degraded and was examined using powder X‐ray diffraction (XRD) and scanning electron microscopy – energy‐dispersive X‐ray (SEM–EDX) in addition to the above‐cited techniques. Other materials used in the polychromatic decorations are Egyptian blue, cinnabar and possibly orpiment, while calcium carbonate was used for the ground layer. The organic materials were identified as beeswax, mastic and gum arabic, sometimes as mixtures.     

PETROGRAPHIC AND CHEMICAL CHARACTERIZATION OF POTTERY PRODUCTION OF THE LATE MINOAN I KILN AT HAGHIA TRIADA,CRETE*

Pottery from the Late Minoan I kiln at Haghia Triada in the Mesara Plain, southern Crete, was analysed by a range of techniques, comprising thin‐section petrography, scanning electron microscopy, X‐ray diffraction, X‐ray fluorescence and neutron activation analysis. The project characterizes the ceramic fabrics and probable raw materials, correlates paste recipes with shape, reconstructs the firing conditions of the kiln and establishes a chemical reference group, taking into account post‐burial alteration and contamination. Comparison of the reference group formed with that from the neighbouring, broadly contemporary, kiln at Kommos shows an unexpected differentiation of the two kilns.     

文物库房的虫害治理

仓库害虫是有机质地物的大致,做好害虫防治工作对于有机质地物保护具有重要的意义。本针对物库房中虫害隐患的现状,分析了隐患产生的原因,提出了预防虫害的措施,并对物保护领域常用的数种杀虫方法作了介绍。     

三组明清织物装饰捻金线的技术分析与比较研究

为了对比分析不同金属线的形貌、材质和工艺差异,理解不同时代金属线差异产生的原因,利用显微形貌观察与科学仪器分析对三组明清纺织品捻金线样品的金属箔条、有机质背层、芯线进行了形貌观察分析。对比了三组捻金线的形貌、结构、尺寸和材质特征,对其制作工艺进行了对比分析,得出了三组捻金线的质量优劣等次,发现了金属线的选用与被装饰织物的时代、功用性质和文化属性之间存在一定关系的现象。含金量高的金属箔条、蚕丝芯线、尺寸纤细、制作精细的捻金线属于高等次的捻金线,常用于等级高、文化属性及功用重要的纺织品文物装饰,其中不带背层的金属线等级又高于带有背层的金属线。本研究对开展金属线系统分析和金属线对比研究具有较高的参考价值。     

First Evidence Of The Use Of Freshwater Pearls As A Cosmetic In Ancient China: Analysis Of White Makeup Powder From A Northern Song Dynasty Lv Tomb (Lantian,Shaanxi Province,China)

The Lv family tombs in Lantian, Shaanxi Province are one of the most important archaeological sites of China in recent years, providing numerous objects and a wealth of information for the study of the history of the Northern Song dynasty. There were a large number of exquisite cultural relics unearthed from the tombs, including one porcelain box containing white powder, which was identified as women's makeup. The phase composition, microstructure, thermal properties and characteristics of the trace elements in the unearthed white cosmetic powder were comprehensively analysed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry – thermogravimetry (DSC–TG), Fourier transform infrared (FT–IR) microscopy and inductively coupled plasma atomic emission spectroscopy (ICP–AES). The white makeup powder was determined to be a product made from high‐quality freshwater pearls. These results, for the first time, showed evidence that freshwater pearl powder was used as a cosmetic in ancient China using archaeological objects, providing scientific evidence and new clues to enrich and expand research into the ancient Chinese cosmetic materials.     

中子衍射和成像技术在文物领域中的应用进展

中子衍射和成像技术是利用中子束穿透性强、元素分辨率高等特点,对物体进行原位、无损和块扫描,实现材料组成定性定量分析和内部结构可视化检测。在此通过介绍中子衍射和成像技术的基本原理和特点,总结其在国内外文物领域的应用研究现状,显示中子衍射和成像技术在文物研究中的突出优势和广阔应用前景,为其在中国文化遗产保护领域的应用研究提供参考。     

NEUTRON ACTIVATION ANALYSIS OF ANCIENT BURMESE SILVER COINS WITH A LOW FLUX AMERICIUM/BERYLLIUM NEUTRON SOURCE

Nondestructive neutron activation analysis is by now a well-established technique for the analysis of ancient silver coins. The high activation cross-section of silver for thermal neutrons makes it possible to also use this method with the low neutron fluxes available from an isotopic neutron source. In this case due consideration must be given to minimize the self-shielding effect which is encountered with coins above a few tenths of a millimetre thickness. A simple method for the determination of the silver, copper and gold content in silver coins based on the self-shielding properties of silver alloys of different fineness is described. The method has been found to be useful for the quick routine assay of silver coins for the purpose of their classification. Seventeen ancient Burmese silver coins from three different cultural periods of Burma, and two British coins for comparison have been analyzed by this method.     

Characterization Of Early Imperial Lacquerware From The Luozhuang Han Tomb,China

This paper focuses on the characterization of materials from fragmented pieces of an imperial lacquer plate in the Luozhuang Han tomb, which dates to the early Western Han dynasty. Various non‐invasive and minimally invasive techniques were performed, including optical and electron microscopy, XRF, Raman spectromicroscopy, FT–IR, XRD and THM‐Py–GC/MS. The lacquerware pieces consist of a five‐layer structure, which includes (from the top): a red pigmented layer, two lacquer finish layers, a ground layer and a canvas/wood foundation layer. The red layer consists of ground cinnabar mixed with urushi. The lacquer finish layers are made of urushi mixed with perilla or tallow tree oil, without any pigment. The ground layer is a mixture of organic materials including urushi, tree oil and amorphous carbon (possibly burned ashes) and inorganic fillers such as quartz, albite and potassium feldspar. Urushi was also identified in the canvas/wood foundation layer. Though highly degraded, the canvas is probably made of hemp (bast fibres). The identification of high concentration of drying oil indicates an intentional addition of oil into the urushi to retard the rate of hardening and to increase gloss.     

CHARMed PyMca,Part I: A Protocol for Improved Inter‐laboratory Reproducibility in the Quantitative ED‐XRF Analysis of Copper Alloys

This paper describes a protocol for quantification of heritage copper alloys by energy‐dispersive X‐ray fluorescence spectroscopy (ED‐XRF). The protocol, nicknamed CHARMed PyMca, is designed for users who wish to maximize inter‐laboratory reproducibility of quantitative ED‐XRF results for the wide range of copper alloys found in heritage materials. By maximizing reproducibility, this protocol should facilitate collaboration and allow the rigorous use of shared data and databases. The protocol uses free, open‐source, fundamental parameters software called PyMca. PyMca allows for a consistent and transparent application of the fundamental parameters approach independent of the ED‐XRF instrumentation used. The proposed protocol calls for calibration of standardless PyMca results against a set of certified reference materials designed specifically for use with heritage copper alloys, the so‐called copper CHARM set. Finally, this protocol calls for the calibration‐to‐standards to be carried out following a consistent strategy, including error modelling and the incorporation of a validation procedure. A reproducibility study was conducted using CHARMed PyMca and eight different ED‐XRF instruments of six different types. In comparison to a 2010 study conducted according to the same method, CHARMed PyMca showed a dramatic improvement in reproducibility and method sensitivity.     

THE CHARACTERIZATION OF PAINTS AND WATERPROOFING MATERIALS FROM THE SHIPWRECKS FOUND AT THE ARCHAEOLOGICAL SITE OF THE ETRUSCAN AND ROMAN HARBOUR OF PISA (ITALY)*

This work presents the results of a diagnostic survey on the shipwrecks from the archaeological site of the ancient harbour of San Rossore (Pisa, Italy). The original waterproofing, caulking and painting materials were characterized by Fourier transform infrared spectroscopy (FTIR), gas chromatography – mass spectrometry (GC–MS), energy‐dispersive X‐ray microanalysis (EDX) and X‐ray diffraction (XRD). The major constituents of the waterproofing and caulking materials detected on the planks were tricyclic abietanes showing a high degree of aromatization. These compounds are indicative of a pitch obtained from the wood of trees of the Pinaceae family. The analysis of the organic components of the paint samples revealed diterpenoid acids characteristic of Pinaceae resins together with linear long‐chain alcohols and fatty acids, highlighting the presence of beeswax. Noticeably, the characteristic odd carbon number alkanes that are normally present in beeswax were not detected. The EDX and XRD analyses showed that hematite, calcite, cerussite and kaolinite were employed as pigments to paint the ships’ hulls.