Neutron and X-ray imaging for Cultural Heritage research

Giulia Festa University of Rome Tor Vergata

University of Milano-Bicocca

Group Research Activities

Research Activities

Sub-femtosecond quantum dynamics in light and heavy atoms

Neutron detectors

developmentCHIP

Irradiation

Neutron applications to

cultural heritage

Simulation

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Neutron applications to Cultural Heritage

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Time Of Flight Neutron Diffraction

Powerful to investigating the crystal structure to the samples

TOF: determination of neutron’s energy for a ‘white beam’ measuring their time of flight

mn = neutron massL = flight length between the moderator to the sampleTOF = employed time to cover the L distance

Bragg’s Law

• Structural informationPhase structure – compound contents Crystal structure – atomic arrangement of each phaseGrain structure – texture (size, shape and orientation grains)Micro-structure – structural deviation from ideal crystal within the grain

• Effects on the diffraction patternsDiffraction peak position: lattice parameters, macro and micro strainDiffraction peak width: particle size, micro-strain broadeningDiffraction peak intensities: atomic arrangement and grain orientation

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Prompt Gamma Activation Analysis

• Based on radiative capture of neutrons (ZA + n→ZA+1 + γ)• Prompt-: measurements during sample irradiation (due to

the de-excitation of the compound nucleus)• Delayed-: due to the beta decay of the new-formation

instable nucleus

spectra:characteristic for any elementused for elemental composition and isotope’s identification

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Neutron Resonance Capture Analysis

NRCA: uses epithermal neutrons (En from 1 eV up to 1 keV) to investigate the elemental composition of the irradiated sample. Neutrons impinging onto materials are captured by the nuclei.

For many nuclear species, especially metals, there are intense peaks in the absorption cross section called resonances. Emitted gammas are detected by a standard photon detector counter as function of Time Of Flight.

150

MeV

LINAC Sample

Udepl

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Neutron radiography/tomography

A non destructive testing.

Principle: when beam pass trough a sample, part of the radiation is attenuated by the material – related with the absorption coefficient

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Radiography/Tomography

Phase+structure+textureAnalysis

By neutron attenuation

Making techniques

Making techniquesGenuine or fake

By neutron diffraction

Neutrons in archaeometry

ProvenanceAttribution

Element Analysis

By neutron activation analysis

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X-Ray / Neutrons cross-sections

• RX scattered by atomic electrons → cross section is linear depended with the square of atomic number

• Neutrons scattered by atomic nuclei → cross section vary from an isotope to an other

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Neutron applied to Cultural Heritage

Research

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Integrated neutron analysis of Ghiberti relief from the Battistero di Firenze

Prompt Gamma Activation Imaging (PGAI)

Gilding state

Neutron Radiography+

Neutron Diffraction

Extension of the secondary fusion

Neutron Diffraction

Difference between two melting: composition and

working methods

Conclusions:

1) Gilding state: Chlorine was detected in the laser-pulished area (to be consider in the choice of microclimatic conditions for conservation) 2) Second fusion and emty volume inside: Definition fo an hollow volume and detection fo the extension of the secondary melting3) Treatments: First fusion thermal treatmentsSecond fusion without treatments

Critical aspects: 1) Gilding state, 2) Extension of the secondary melting, 3) Study of the two melting about composition and working methods

1) G. Festa, C. Andreani, et al., Journal of Applied Physics, 106, N.4 (2009).2) G. Festa, R. Senesi, C. Andreani, et al., Journal of Applied Physics, 109, n.6 (2011)

A Neutron-Gamma Logging System for Applications to Cultural Heritage (a Monte Carlo Study) 

Neutron-gamma logging is a nuclear technique based on the measurement of gamma rays under neutron irradiation. We investigate the feasibility of the technique for applications in cultural heritage by using Monte Carlo simulations.

Simulated neutron logging system inside borehole.

Simulated energy spectrum measured by the gamma ray detector.

Simulated neutron capture gamma ray spectra with (top) and without (bottom) copper sample in the energy region 6.5 – 8 MeV.

1) A. Miceli, G. Festa, R. Senesi, C. Andreani, et al., atti di convegno Fotonica 2013, AEIT codice ISBN 9788887237160 2) A.Miceli, G. Festa, R. Senesi, C. Andreani et al., in pubblicazione come contribution for Proceedings of the 17th CHNT peer reviewed

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Bi-parametric time-energy acquisition Prompt Gamma Activation Analysis (T-PGAA) for Cultural Heritage studies.

The time-resolved Prompt Gamma Activation Analysis consists in the measurement of gamma energy spectrum induced by radiative capture as a function of incident neutron Time Of Flight.

Layout of the designed experiment and n-gamma spectra recorded at different time of flight t0<t1<t2

Simulated gamma spectra (a) neutron resonance energy range from 200eV to 900eV (b) total neutron energy range from 0 to 1.2 KeV.

Potential to enhance the capabilities of both the NRCA and PGAA techniques, providing a simultaneous element sensitivity not currently available.

1) G. Festa, A. Miceli, R. Senesi, C. Andreani et al. atti di convegno Fotonica 2013, AEIT codice ISBN 9788887237160 2) A.Miceli, G. Festa, R. Senesi, G. Gorini, C. Andreani. Under review for Journal of Physics: Conference Series (2013)

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Neutron and X-ray Imaging applied to Cultural Heritage

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Simultaneous and integrated neutron-based techniques for material analysis of a metallic ancient flute

A metallic 19th century flute instrument coming from ‘Accademia Nazionale di Santa Cecilia’ was studied by : Neutron Diffraction, Neutron Radiative Capture Analysis and Neutron Radiography.

The aim of this study is showing the potential application of the multiple and integrated neutron-based techniques approach for musical instruments.

Results: a non homogeneous composition of the flute. The body of the instrument is mainly composed of zinc covered by palladium (generally used for larger organ pipes), mouthpiece mainly composed by lead (material typically used for organ pipes of small dimensions).

1) G. Festa, C. Andreani, et al., In pubblication in Measurement Science and Technology (giugno 2013)

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Neutrons and X-ray imaging to study wood musical instruments.

Six musical instruments and two instrument cares coming from the 'Fondo Antico della Biblioteca del Sacro Convento' in Assisi, Italy, were investigated by Neutron and X-ray radiographies-tomographies.

Measurements dedicated to studying: the internal structure of the samples, position of added materials like metals, the wood fibre displays, deformations, presence of adhesives and their spatial distribution to give information about construction methods and guide the restoration process.

In collaboration with Giovanni Tardino (BauArt, Basel)

1) G. Festa, C. Andreani, et al., In preparation

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Photo 3D reconstruction – isosurface 3D reconstruction – isosurface

In collaboration with the’ Servizio di Antropologia Soprintendenza Beni Archeologici Lazio’

Examination of human fossil materials through X-ray tomography

1) M. Rubini, V. Cerroni, G. Festa, R. Sardella, P. Zaio, In preparation for Journal of Human Evolution (2013)

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Thank you.

Team: Prof. C. Andreani, G. Festa, A. Miceli, R. Senesi