xxiii πανελληνιο ÏƒÏ Î½ÎµÎ´ÏÎ¹Î¿ Ï†Ï ÏƒÎ¹ÎºÎ·Ï‚ στερεας καταστασης & επιστημης ...

Simulating the neutron diffraction profiles of the mineralogical variations during firing
in ancient ceramics
I.M.Siouris 1 , V.Moumtzi 2 ,F.Moumtzis 2 ,, W. Kockelmann 3
1
Department of Production and Management Engineering , Democritus University of Thrace
Xanthi, 67 1 00 Xanthis, Greece
2 Altec SA, Research Programmes Division, 56429 Thessalonica, Greece
3 Rutherford Appleton Laboratory, ISIS Facility, OX11 0QX Chilton, United Kingdom
*jsiou@pme.duth.gr
The possibility to perform quantitative phase analysis on intact archaeological ceramic objects or pottery
fragments by neutron diffraction (ND) was extensively demonstrated before [1,2]. However, the determination
and interpretation of maximum firing temperatures is the subject of many debates in the archaeology community
[3]. The knowledge of the mineral content and the firing temperatures are of interest since they permit an
assessment of the raw materials used and of details of the firing procedures. This information may allow for an
assessment of the technical skills of the ancient potters and hence on the cultural achievements of ancient
civilizations. When only oxidizing firing is considered, the physical and chemical transformations taking place in
pottery clays cannot be reversed by firing again below the original firing temperature [4]. Such in-situ
measurements of mineral phase transformation are well performed on a neutron diffractometer that do not
require detector scans. The current study was the first part of a proposed systematic investigation, using TOF-
ND, on the characterization of ancient pottery from different periods ranging from prehistoric to 1 st
century BC, found at various excavation sites in North Greece. The aim of this project is to supply a
ceramic/pottery database on the constituent minerals, firing and weathering conditions, to both archaeologist and
scientists in the field. The present experiment was performed in two steps. First, each of the eight ceramic pieces
of approximate dimensions 3 - 15 cm 2 and 0.7 – 1.5 cm thick, were exposed to the beam for several hours at
room temperature and ND patterns were collected (Fig. 1).
Fig.1: Observed diffraction patterns collected at room temperature of seven ceramic samples.
During the second step a single piece of very low fired pottery from Karabournaki was selected for
firing measurements in a furnace. In-situ of ND patterns were collected (Fig.2). The aim was to estimate the
firing temperature by re-firing pottery samples on the beam line and record the neutron diffraction pattern after
each firing step. The starting temperature was 600 ºC and the first significant changes in the diffraction pattern
were observed for temperatures above 650 ºC. Then the temperature was increased from 700 to 975 ºC in
steps of 25 ºC. The neutron diffraction data was analyzed and structure refinement on the observed mineral
phases was performed using the program AMPhOrAe (Archeometric Multi Phase Ornament & Artefacts
analyses)[5]. This program was developed to serve the multiphase modeling requirements of TOF –ND data
analysis. The neutron diffraction data was analyzed and structure refinement on the observed mineral phases
was performed using the program AMPhOrAe (Archeometric Multi Phase Ornament & Artefacts analyses)[5].
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