The discovery of ancient artefacts and artworks usually raises a variety

of questions such as the correct determination of their historical and cultural

timeframe, the place and method of production, the choice of treatments and conditions

for restoration and preservation. In the field of archaeometry, new perspectives

are opened up by the use of neutron techniques. Results on a selection of archaeological

samples, Etruscan bronzes coming from the Museo Nazionale di Villa Giulia and Roman marbles from Villa Adriana (Tivoli, Rome), are presented. ANCIENT

CHARM project aims to develop a quantitative 3D imaging technique. This work presents some of results on a series of experimental investigation performed on test

samples called “Black Boxes”. Elements’ and compounds’ identification on the internal features of the boxes are obtained by the combined use of different neutron analysis methods. The presented studies successfully showed the high potential of neutron techniques in the study of ancient archaeological artefacts

Andreani, C

Cattaneo, R

Festa, G

Gorini, G

Perelli Cippo, E

Pietropaolo, A

Tardocchi, M

Archivio della Ricerca - Università di Roma Tor vergata

DOI 10.1393/ncb/i2008-10418-9
IL NUOVO CIMENTO Online First
Study of archaeological samples via neutron techniques
G. Festa for the Ancient Charm Collaboration
Centro NAST and Dipartimento di Fisica, Universita` di Roma “Tor Vergata”
Via Ricerca Scientiﬁca 1, 00133 Rome, Italy
(ricevuto il 7 Gennaio 2008; approvato il 14 Febbraio 2008; pubblicato online il 14 Aprile 2008)
Summary. — The discovery of ancient artefacts and artworks usually raises a va-
riety of questions such as the correct determination of their historical and cultural
timeframe, the place and method of production, the choice of treatments and condi-
tions for restoration and preservation. In the ﬁeld of archaeometry, new perspectives
are opened up by the use of neutron techniques. Results on a selection of archaeo-
logical samples, Etruscan bronzes coming from the Museo Nazionale di Villa Giulia
and Roman marbles from Villa Adriana (Tivoli, Rome), are presented. ANCIENT
CHARM project aims to develop a quantitative 3D imaging technique. This work
presents some of results on a series of experimental investigation performed on test
samples called “Black Boxes”. Elements’ and compounds’ identiﬁcation on the in-
ternal features of the boxes are obtained by the combined use of diﬀerent neutron
analysis methods. The presented studies successfully showed the high potential of
neutron techniques in the study of ancient archaeological artefacts.
PACS 83.85.Hf – X-ray and neutron scattering.
PACS 89.90.+n – Other topics in areas of applied and interdisciplinary physics.
The discovery of ancient artefacts and artwork usually raises a variety of questions
such as the correct determination of their historical and cultural timeframe, the place
and method of production, the choice of treatments and conditions for restoration and
preservation.
In the ﬁeld of archaeometry, new perspectives are opened up by the use of neutron
techniques. Neutron is a very suitable means for the collection of information from
the bulk of large cultural-heritage objects. In fact neutrons penetrate through objects
without substantial attenuation, a property that makes them ideal for non-destructive
testing.
Information on the artefacts is relative to composition, presence of alteration, crusts,
inclusions, structure of the bulk, typology of the location of materials extraction, manu-
facturing techniques, refractoriness, porosity, ﬁring temperature. Provenance and state
of conservation of ancient objects are of key importance to address matters of attribution
and restoration of archaeological objects.
A recent preliminary application of neutron techniques in the cultural-heritage ﬁeld
is a neutron diﬀraction study of marbles from Villa Adriana in Tivoli (Rome) [1, 2]
c© Societa` Italiana di Fisica 1
2 G. FESTA FOR THE ANCIENT CHARM COLLABORATION
Fig. 1. – View of Villa Adriana site, Tivoli, Rome, Italy.
(see ﬁg. 1). Villa Adriana is an exceptional complex of classical buildings designed and
erected in the 2nd century AD by the Roman emperor Hadrian, and is recorded by the
UNESCO in the World Heritage List. Analytical investigations on monumental com-
plexes of the Roman Empire age complement the studies carried out on architectural
and building engineering in order to achieve unitary views on this historical period. In
this context, neutron diﬀraction techniques have been used for the characterisation of
ancient Roman marble fragments from the Ediﬁcio con Tre Esedre palace, located in
Villa Adriana. The marble decorations were built with a technique known as opus sec-
tile, typical of Hadrian’s time, with wall decorations belonging to the 2nd century AD.
A reconstruction of the Palace’s marble wall decoration positioning is shown in ﬁg. 2.
Fragments of such decorations (used as samples) are shown in ﬁg. 3. Marble is one of the
most common stones used for monuments, statues and other objects of archaeological
interest and is typically composed of either calcite or dolomite or a combination of the
two. The ongoing study aims at distinguishing diﬀerent marble types on the basis of the
mineral phase compositions and the crystallographic textures. Information obtained can
be used to distinguish diﬀerent types and hopefully identify the origin of the diﬀerent
marbles. The diﬀraction experiments on marbles were performed on the Time-Of-Flight
(TOF) diﬀractometers GEM, INES and ROTAX located at ISIS Neutron Spallation
source (UK). The use of multi-detector TOF neutron diﬀractometers allows us to per-
form quantitative analysis on stationary samples in a reasonably short time (from a few
minutes to a few hours according to instrumentation and sample characteristics). This
technique has many advantages: a stationary experimental set-up to collect a complete
diﬀraction pattern can be used, objects of variable shapes or sizes can be illuminated
STUDY OF ARCHAEOLOGICAL SAMPLES VIA NEUTRON TECHNIQUES 3
Fig. 2. – Reconstruction of the marble wall decoration of the Palace Ediﬁcio con Tre Esedre.
without prior preparation, and composition and preferred orientation or texture eﬀects
are easily recognised. Multi-phase and multi-bank analyses of the diﬀraction patterns
were carried out with standard crystallographic public-domain software (GSAS [3] for
quantitative phase analysis and MAUD [4] for texture analysis). An example of exper-
imental data for marble 11, together with the ﬁnal GSAS Rietveld reﬁnement is shown
in ﬁg. 4.
The texture information is displayed in pole ﬁgures. Pole ﬁgures are the “maps” of
the crystal grains orientations, caused in marbles by geological processes, and can be
used as a ﬁngerprint to identify them. In ﬁg. 5 a sketch of a pole ﬁgure reconstruction
from the diﬀraction measurements for marble fragments is shown. Pole ﬁgures indicate
deviations from a random crystallite orientation distribution (e.g., in sample n. 17).
Another recent application of neutron techniques was performed on bronze samples
(ﬁgs. 6 and 7) coming from the Museo Nazionale di Villa Giulia, Rome, Italy. Non-
destructive Neutron Diﬀraction (ND) on VIII century BC laminated Etruscan bronzes
was performed with the aim of collecting information related to the main composition of
the artefacts, the presence and nature of alterations or inclusions and the bulk structure.
The experiments were carried out at ISIS spallation neutron source. The bronze vases are
part of an Etruscan collection discovered in the necropolises of Osteria-Poggio Mengarelli
and Cavalupo in the outskirts of Vulci (Viterbo, Italy).
The samples, 14 fragments, were analysed with regard to chemical-phase compositions
and corrosion products. Bronze is composed of copper, tin (Cu, 85–95%, Sn, 5–15%) and
small quantities of other metals. The determination of the exact copper/tin/lead rela-
tive composition provides important information on the working process and technologies
adopted and, indirectly, on the authenticity of the artefacts. Furthermore the presence of
other components, like corrosion products, is linked to the past environment and to the
4 G. FESTA FOR THE ANCIENT CHARM COLLABORATION
Fig. 3. – Marble fragments coming from Villa Adriana site.
Fig. 4. – Example of ﬁnal GSAS Rietveld reﬁnements plot for one of the marble samples (no. 11).
STUDY OF ARCHAEOLOGICAL SAMPLES VIA NEUTRON TECHNIQUES 5
Fig. 5. – Marbles from Villa Adriana: texture reconstruction along the (006) axis. Pole ﬁgures.
Samples n. 3, 18, 22, 9, 11, 28, 16, 17.
physical and chemical events that transformed the object into a partially corroded matrix
(e.g., burial environment or exposure to the atmosphere, marine conditions and labora-
tory environment) [5]. An example of experimental data for bronze samples, together
with the ﬁnal GSAS Rietveld reﬁnement is shown ﬁg. 8.
Results obtained from ND investigation of objects show that 60% to 95% by weight is
uncorroded alloy that presents a composition (Cu = 90± 4%) which is typical of low-tin
Fig. 6. – Etruscan bronze cup coming from Museo Nazionale di Villa Giulia.
6 G. FESTA FOR THE ANCIENT CHARM COLLABORATION
Fig. 7. – Etruscan bronze vase coming from Museo Nazionale di Villa Giulia.
Fig. 8. – Example of ﬁnal GSAS Rietveld reﬁnements plot, sample no. 6, detector bank no. 1
at 2θ = 163. Components: bronze (Cu/Sn), cuprite (Cu2O), lead, tenorite (CuO), nantokite
(CuCl).
STUDY OF ARCHAEOLOGICAL SAMPLES VIA NEUTRON TECHNIQUES 7
Fig. 9. – Relative variation of the bronze-Bragg peak width for the diﬀerent samples.
ancient bronzes, thus supporting the authenticity of the samples. ND measurements also
provided information about working methods of bronzes through the analysis of relative
bronze peaks width Δd/d as a function of d-spacing (see ﬁg. 9): annealing and two
diﬀerent types of cooling dynamics (fast and slow) are present while hammering could
also be present. Furthermore ND data analysis showed that the combination of corrosion
products in the single samples is in agreement with possible environmental conditions
in which the objects were in contact. Most of the samples were buried. Some of these
were in contact with salted water. This could come from seawater percolation or simply
salted food contained in the vases. Additionally it has been possible to trace probable
quantitative values for the concentration of certain environment components such as CO2
and NaCl present in the tombs.
In this context ANCIENT CHARM (Analysis by Neutron resonant Capture Imag-
ing and other Emerging Neutron Techniques: new Cultural Heritage and Archaeological
Research Methods) is a research project funded by the European Commission under
the “New and Emerging Science and Technology” programme. The aim of the project
is to develop non-invasive 3D tomographic imaging of the elemental and phase compo-
sition based on established neutron techniques as Neutron Resonant Capture Analysis
(NRCA), Prompt Gamma Activation Analysis (PGAA) and Neutron Diﬀraction (ND) [6]
for cultural heritage.
In order to develop a protocol with the aim of combining Tomography, Prompt
Gamma Activation Analysis (PGAA) and Neutron Diﬀraction (ND) data collected on
the same archaeological object, test samples of varying complexity were constructed and
analysed by the diﬀerent neutron methods. Two series of closed and sealed “Black Boxes”
have been constructed by Bonn University, Germany and by the Hungarian National Mu-
seum. The ﬁrst set consists of ten hollow aluminium cubes of 40mm edge length that
8 G. FESTA FOR THE ANCIENT CHARM COLLABORATION
Table I. – Results coming from prompt gamma activation analysis (PGAA) measurements (a)
and from neutron diﬀraction (b). The numbers identiﬁcate the zone of neutron irradiation and
are the same of ﬁg. 10 (a,b).
contain 2D or 3D arrangements of materials that are relevant for archaeological samples.
The second set consists of similar pieces yet made of iron and with edge length of 50mm.
The inner composition and the distribution of the ﬁlling materials were initially known
exclusively by the creators. The aim of such “blind” investigations is to assess potential-
ities and limitations of each technique and the eﬀects of technique combinations [7].
In fact ND provides information about compounds while PGAA about elements. The
combination of both techniques gives a good picture of the inside of the objects. As an
example table I a,b reports the ND and PGAA results on Bonn Al4 “Black Box” (ﬁg. 10).
The ﬁnal interpretation of the resulting data is that the box is divided into two parts
with diﬀerent ﬁlling materials: salt (NaCl) and clay consisting of quartz (25 wt% SiO2)
and calcite (75wt% CaCO3). The objects in the two chambers are made of diﬀerent
materials: two of these are made of a f.c.c.-structure of Cu-type and two of a b.c.c.
lattice speciﬁcally made of ferrite (Fe). Therefore, the main components are identiﬁed
by TOF-ND. PGAA is required to unambiguously detect the f.c.c.-material by providing
the elements it is made of. The clay is composed by two main components which were
identiﬁed with approximately the correct proportions, also an extra phase (the cementite)
was observed in the ferrite.
STUDY OF ARCHAEOLOGICAL SAMPLES VIA NEUTRON TECHNIQUES 9
Fig. 10. – X-ray radiographies of test sample (Al4 “Black Box”). There are evident the points
of irradiation during the diﬀerent measurements: (a) prompt gamma activation analysis, (b)
neutron diﬀraction. The numbers of the points are the same of table I (a,b).
The study was completed through the identiﬁcation of the spatial distribution of the
internal objects in the “Black Boxes” via X-ray radiography and neutron tomography.
Conclusions
Neutron techniques are very suitable for non-destructive investigation of bulky archae-
ological samples. With regard to such diverse objects interesting results were observed.
Marbles and stones coming from Villa Adriana were studied via ND obtaining com-
positional and textural information related to the geological characteristics.
Etruscan bronzes coming from the Museo Nazionale di Villa Giulia were analysed with
the aim to determine the corrosion products which are directly related to conservation
environment, alloy composition and working methods.
Studies on test samples (“Black Boxes”), within the Ancient Charm European re-
search project, were performed. These studies successfully showed the high potential of
neutron techniques in the study of ancient archaeological artefacts.
∗ ∗ ∗
The authors acknowledge Consiglio Nazionale delle Ricerche (CNR-Italy) for ﬁnancial
support, within the agreement CNR-CCLRC ISIS and ISIS sample environment team.
Work performed with ﬁnancial support by the European Community “New and Emerging
Science and Technology” Contract No. 15311.
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10 G. FESTA FOR THE ANCIENT CHARM COLLABORATION
[3] Larson A. C. and Vondreele R. B., GSAS: Generalized Structure and Analysis Software,
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Study of archaeological samples via neutron techniques

The discovery of ancient artefacts and artworks usually raises a variety
of questions such as the correct determination of their historical and cultural
timeframe, the place and method of production, the choice of treatments and conditions
for restoration and preservation. In the field of archaeometry, new perspectives
are opened up by the use of neutron techniques. Results on a selection of archaeological
samples, Etruscan bronzes coming from the Museo Nazionale di Villa Giulia and Roman marbles from Villa Adriana (Tivoli, Rome), are presented. ANCIENT
CHARM project aims to develop a quantitative 3D imaging technique. This work presents some of results on a series of experimental investigation performed on test
samples called “Black Boxes”. Elements’ and compounds’ identification on the internal features of the boxes are obtained by the combined use of different neutron analysis methods. The presented studies successfully showed the high potential of neutron techniques in the study of ancient archaeological artefacts

FESTA, GIULIA

ANDREANI, CARLA

Tardocchi, M.

English

FESTA, G

ANDREANI, C

Cineca Institutional Research Information System

https://art.torvergata.it/retrieve/handle/2108/54057/11490/ncb10261-ARTICOLO%20SIF.pdf

Study of archaeological samples via neutron techniques

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