DOI: 10.5281/zenodo.4018839
title: EDS and XRD analysis of medieval ceramics from Beaupréau-en-Mauges (France)

description: This dataset contains analyses of 76 ceramic samples from the medieval workshop of Les Landes (Beaupréau-en-Mauges, Maine-et-Loire, France). The chemical composition of the samples was obtained by energy-dispersive X-ray fluorescence spectrometry (EDS). The mineralogical composition of the samples was studied by powder X-ray diffraction (XRD).

Method

The outer surfaces of all the samples were mechanically removed prior to analysis.

EDS

The samples were heated to 950°C for one hour after 24h drying at 50°C, weighted for LOI calculation and ground in a tungsten carbide mortar. Measurements were made on pelletized powders.

The data were collected by energy dispersive X-ray fluorescence spectrometry (Oxford INCA 300 spectrometer) coupled with scanning electron microscopy imaging (JEOL JSM 6460LV variable pressure microscope). The measurements were carried out under partial vacuum (20 Pa) with an acceleration voltage of 20 kV. The acquisition time is 90 s per spectrum, over the energy range 0-20 keV. For all EDS spectra, the dead time during acquisition is about 30%, for an average number of hits per spectrum greater than 106. The compositions are calculated from Oxford Instruments standards made of metals, synthetic compounds and natural minerals.

Six measurements were carried out on each pellet (the area analyzed during each measurement is approximately 5.10-2 mm2). The results are expressed in mass percentages of oxides and are normalized to 100%. Ten major elements were quantified: Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3 (total iron). Although results of elementary composition below 0.5 wt% lack quantitative precision, they are mentioned in the general composition as they hold qualitative information. Values below 0.01% must be considered unreliable.

The EDS.csv file contains all the chemical compositions, with the following columns:



sample: sample reference.

analysis: analysis reference (1 to 6 per sample).

date: date of the analysis.

laboratory: analysis laboratory.

fait, stratigraphy, isolat: stratigraphic unit.

artefact: typology.

LOI: loss on ignition (percent).

Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3 (total): oxide mass percents.


XRD

The data were collected with a D8 Advance (Bruker) diffractometer in Bragg-Brentano configuration working at 1.6 kW (40 kV, 40 mA) and equipped with a copper anode source (kα1 = 1.5406 ; the kβ ray being removed by a Ni-filter in the diffracted beam). The tube was equipped with a 0.3° divergence slit and an 8 mm anti-scattering slit was mounted in front of the LynxEye© CCD detector.

Data recording was performed from 3° to 70° (2θ), in steps of 0.02° with an acquisition time of 2 s, the sample being rotated. The stability of the device was controlled between the different series of measurements by the analysis of a standard (corundum crystal, NIST 1976).

The XRD.zip archive contains all diffractograms in the Bruker raw format. The XRD.csv file contains all results expressed in counts, one sample per row, the first line gives the angular position (2 thêta) and the first columns contains the sample code.