The Use of Neutron Analysis Techniques for Detecting The Concentration And Distribution of Chloride Ions in Archaeological Iron

Chloride (Cl) ions diffuse into iron objects during burial and drive corrosion after excavation. Located under corrosion layers, Cl is inaccessible to many analytical techniques. Neutron analysis offers non‐destructive avenues for determining Cl content and distribution in objects. A pilot study used prompt gamma activation analysis (PGAA) and prompt gamma activation imaging (PGAI) to analyse the bulk concentration and longitudinal distribution of Cl in archaeological iron objects. This correlated with the object corrosion rate measured by oxygen consumption, and compared well with Cl measurement using a specific ion meter. High‐Cl areas were linked with visible damage to the corrosion layers and attack of the iron core. Neutron techniques have significant advantages in the analysis of archaeological metals, including penetration depth and low detection limits.     

Comparison of analytical techniques for analysis of archaeological bronze

While many analyses of archaeological bronzes have been reported in the literature, in practice it is very difficult to compare them. To assess the present status of the chemical analysis of bronze two ancient objects—a flat axe (arsenic bronze) and a sickle (tin bronze)—were cut into pieces weighing about 2 g each and were distributed to 11 laboratories. The participants used the following methods for analysis: INAA, ED–XRF, PIXE, TRXRF, FAAS, ICP–AES, ICP–MS, SEM–EDS, LA–ICP–MS and PGAA. The samples were analysed in at least quadruplicate. Dixon's and Iglewicz and Hoaglin's tests were used to detect outliers. The majority of methods provided comparable results, especially for macroelements, independent of the technique and standards used. The number of determined elements depended on the method and, naturally, on the concentration level. Therefore an important recommendation that can be made is to supply, with each archaeometric investigation, data from the analysis of appropriate Certified Reference Materials (CRMs) used in the study.     

COLD NEUTRON PROMPT GAMMA ACTIVATION ANALYSIS—A NON‐DESTRUCTIVE METHOD FOR CHARACTERIZATION OF HIGH SILICA CONTENT CHIPPED STONE TOOLS AND RAW MATERIALS*

Recently, several archaeometrical projects have been started on the prehistoric collection of the Hungarian National Museum. Among the analytical methods applied, non‐destructive prompt gamma activation analysis has a special importance. We have also tested the potential of this method on chipped stone tools, with the aim of determining their exact provenance. On the basis of major and trace element components, characterizations of stone tools and their raw materials—silicites (flint, chert, radiolarite and hornstone) as well as volcanites (felsitic porphyry and obsidian)—were performed. We discuss some important results concerning each group, as case studies. Compiling the data set of different PGAA analysis series, compositions of 110 samples are reported, including 76 archaeological pieces. In the future, we plan to extend the number of investigated objects in each class.