Neutron and X-ray imaging for
Cultural Heritage research
Giulia Festa
University of Rome Tor Vergata
University of Milano-Bicocca
Group Research Activities
Sub-femtosecond quantum
dynamics in light and heavy
atoms
Simulation
Research Activities
Neutron
detectors
development
Neutron
applications to
cultural heritage
CHIP Irradiation
Neutron applications to
Cultural Heritage
3/07/2013
Giulia Festa
3
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
•
Bragg’s Law
•
mn = neutron mass
L = flight length between the moderator to the sample
TOF = employed time to cover the L distance
3/07/2013
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, microstrain broadening
Diffraction peak intensities: atomic
arrangement and grain orientation
Giulia Festa
4
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
3/07/2013
Giulia Festa
5
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.
Udepl
Sample
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.
3/07/2013
Giulia Festa
6
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
3/07/2013
Giulia Festa
7
Neutrons in archaeometry
Element
Analysis
Radiography/
Tomography
By neutron
diffraction
By neutron
activation
analysis
By neutron
attenuation
Making techniques
Genuine or fake
Provenance
Attribution
Making
techniques
Phase+structure
+texture
Analysis
3/07/2013
Giulia Festa
8
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
3/07/2013
Giulia Festa
9
Neutron applied to
Cultural Heritage
Research
3/07/2013
Giulia Festa
10
Integrated neutron analysis of Ghiberti relief from the Battistero di Firenze
Critical aspects: 1) Gilding state, 2) Extension of the secondary melting,
3) Study of the two melting about composition and working methods
Prompt Gamma Activation
Imaging (PGAI)
Conclusions:
Gilding state
Neutron Radiography
+
Neutron Diffraction
Extension of the secondary
fusion
Neutron Diffraction
Difference between two
melting: composition and
working methods
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
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)
11
A Neutron-Gamma Logging System for Applications to
Cultural Heritage (a Monte Carlo Study)
Counts
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.
104
Simulated energy
spectrum measured by
the gamma ray detector.
103
102
10
1
0
2000
4000
6000
8000
Gamma-ray energy (keV)
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
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 ngamma 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)
13
Neutron and X-ray Imaging
applied to Cultural Heritage
3/07/2013
Giulia Festa
14
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)
15
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
16
Examination of human fossil materials
through X-ray tomography
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)
17
Counts
Thank you.
104
103
102
10
1
0
2000
4000
6000
8000
Gamma-ray energy (keV)
Team: Prof. C. Andreani, G. Festa, A. Miceli, R. Senesi
3/07/2013
Giulia Festa
18