Neutron and X- ray imaging for Cultural Heritage research

1. Neutron and X-rayimaging for Cultural Heritage research Giulia Festa University of Rome Tor Vergata University of Milano-Bicocca

2. Group Research Activities Sub-femtosecond quantum dynamics in light and heavy atoms Simulation Research Activities Neutron detectors development CHIP Irradiation Neutron applications to cultural heritage

3. Neutron applications to Cultural Heritage Giulia Festa

4. 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 Structural information Phase structure – compound contents Crystal structure – atomic arrangement of each phase Grain structure – texture (size, shape and orientation grains) Micro-structure – structural deviation from ideal crystal within the grain Effects on the diffraction patterns Diffraction peak position: lattice parameters, macro and micro strain Diffraction peak width: particle size, micro-strain broadening Diffraction peak intensities: atomic arrangement and grain orientation Bragg’s Law mn = neutron mass L = flight length between the moderator to the sample TOF = employed time to cover the L distance Giulia Festa

5. 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 element • used for elemental composition and isotope’s identification Giulia Festa

6. U depl Sample 150 MeV LINAC 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. Giulia Festa

7. 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 Giulia Festa

8. Neutrons in archaeometry Element Analysis Phase+structure +textureAnalysis Radiography/Tomography Byneutronactivationanalysis Byneutronattenuation Byneutrondiffraction Making techniques Making techniques Genuineorfake ProvenanceAttribution Giulia Festa

9. X-Ray / Neutrons cross-sections • RX scattered by atomic electrons → cross section is linear depended with the square of atomic number • Neutrons scattered byatomic nuclei → cross section vary from an isotope to an other Giulia Festa

10. Neutronapplied to Cultural Heritage Research Giulia Festa

11. Critical aspects: 1) Gilding state, 2) Extension of the secondary melting, 3) Study of the two melting about composition and working methods Prompt Gamma ActivationImaging (PGAI) • Gilding state 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 melting 3) Treatments: First fusion  thermal treatments Second fusion without treatments NeutronDiffraction NeutronRadiography + NeutronDiffraction Difference between two melting: composition and working methods • Extension of the secondary fusion Integrated neutron analysis of Ghibertirelief from the Battistero di Firenze • 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)

12. 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 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. Simulated neutron logging system inside borehole. 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

13. 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. Simulated gamma spectra neutron resonance energy range from 200eV to 900eV 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. Andreaniet 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) Layout of the designed experiment and n-gamma spectra recorded at different time of flight t0<t1<t2

14. Neutron and X-rayImagingapplied to Cultural Heritage Giulia Festa

15. 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)

16. Neutrons and X-rayimaging to studywood musical instruments. Six musical instruments and two instrument cares coming from the 'FondoAnticodellaBiblioteca del SacroConvento' 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

17. Examination of human fossilmaterialsthrough X-raytomography Photo 3D reconstruction – isosurface 3D reconstruction – isosurface In collaboration with the’ Servizio di Antropologia Soprintendenza Beni Archeologici Lazio’ • 1) M. Rubini, V. Cerroni, G. Festa, R. Sardella, P. Zaio, In preparation for Journal of Human Evolution (2013)

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