Nuclear Physics techniques and methods for Cultural Heritage - P.A. Mandò - Bruxelles
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Nuclear Physics techniques
and methods for Cultural Heritage
P.A. Mandò
Bruxelles
TechItaly
October 4, 2012
Main contributions of Nuclear Physics (principles and technologies) to the diagnostics of Cultural Heritage •dating 14C (radiocarbon), luminescence techniques •material analysis Ion Beam Analysis (IBA), X Ray Fluorescence (XRF) 2
In Italy....
long tradition of IBA applied to Cultural
Heritage problems
in Florence, e.g., we
started more than 25 years
ago using an old 3 MV
Van de Graaff accelerator
inherited from previous
INFN experiments
we have now a dedicated laboratory, based on state-of-the-art
instrumentation, working in close contact with humanists,
conservation institutions and other scientists, in Italy and in
Europe
Laboratoire de Recherche des Musées de France - Louvre
Max Planck Institut für WissenschaftsGeschichte Berlin
Centro de Micro Análisis de Materiales Madrid
Centro Nacional de Acceleradores Sevilla
University of Surrey, Guildford
International Atomic Energy Agency
Tandetron accelerator, 3 MV max terminal voltage
Ion Beam Analysis (IBA)
• Material composition analysis through beam particle
bombardment
– typically proton or alpha beams at some MeV energy
Radiation detection and Emission of radiation of
spectral analysis characteristic energies
1000
800
Si Lapislazzuli
(X-rays, g, particles…)
Conteggi
600
Al
400
S Ca
200 Na
K
0
particle beam
Object to
particle accelerator analyse
Ion Beam Analysis (IBA)
Ion Beam Analysis (IBA)
X ray
emission
(PIXE)
a
secondary
particles emission
or inelastic
scattering of
incident ions
elastically
scattered gamma ray
particles (PESA) emission
(PIGE)
Pros of IBA techniques
NON invasive, NON destructive, NO damage
widely multi-elemental
(simultaneous detection of almost all elements)
very reliable quantitative analysis
information (through PESA or differential PIXE)
also on layer structure if present, as is often the
caseAn essential facility to perform IBA
especially in the field of Cultural Heritage
The external beam set-up
1 cm
11At LABEC, two dedicated external beamlines
Beam defined by collimation Strong focusing system
(Ø 0.2 ÷ 1 mm) (Ømin 8 – 10 mm)Using external beam set-ups
we can investigate
in a totally non-destructive way
the complete quantitative
composition of any kind of artworkAnalysis of stone manufacts,
“Disc with star”, and jewel case, from “Collezione Medicea di Pietre
Ornamentali”, Natural History Museum, Florence...ancient illuminated ...historical documents,
manuscripts,
External-beam PIXE analysis of the
frontispiece of Pl.16,22 (XV century, Inks in Galileo’s manuscripts (Florence
Biblioteca Laurenziana in Florence) National Library) analysed by external PIXE...drawings, PIXE-PIGE analysis of a drawing on PIXE-PIGE analysis of a drawing on prepared paper, by Leonardo or his school prepared paper, school of Verona, XVI cent.
...paintings on wood or canvas,
Differential PIXE and PIGE analysis of the Micro-PIXE and -PIGE analysis of the
Madonna dei Fusi by Leonardo “Ritratto Trivulzio” by Antonello da MessinaGiorgio Vasari Andrea Mantegna
S.Lucia, from Pala Albergotti, Madonna col Bambino, painting on
Arezzo canvas, Accademia Carrara di Bergamo...glazed terracottas, ...metal manufacts
External PIXE analysis of the
“Ritratto di fanciullo” by Luca Della PIXE and PESA analysis of some gilded
Robbia – before restoration at the chalices from the Museum of Casa Siviero,
Opificio delle Pietre Dure in Florence
FlorenceIBA with an external scanning
ion microbeamIon beam
One can reconstruct elemental maps
something similar to what is done with the well
known scanning electron microprobe (EMPA),
but with two main crucial advantages:
• much better sensitivity (trace elements)
• even more important for C.H., the “target” is
not in vacuum: no need of picking up
samples from the workDiagnostics of ink elements distribution in
a XVII century document
2 mm S
max
2 mm
Ca Fe Cu
min
damage
2 mm S Ca Fe
precursor?Antonello da
Messina
Portrait of a man
(also known as
Ritratto Trivulzio)
Torino, Museo Civico
di Palazzo Madama
Oil painting on wood,
38 x 30
1476 2526
27
28
Ritratto Trivulzio: scanning PIXE measurements
Max. HgM+SK Immagine ottica
Min. 1 mm
AlK KK
1 mm
Al and K are correlated with darker areas ( red lacquer) and
are on surface; Hg and S (cinnabar) come from belowMantegna, Madonna col Bambino (1460)
Accademia Carrara (Bergamo)
2 mm
Au Lα Pb Lα
Sn K Fe
2 mm
Au Lα
30
Si Al Pb LαArchaeological dating
The 14C method is a great contribution of
Nuclear Physics to Archaeology
The method is indeed based on a naturally
occurring nuclear phenomenon, i.e. the
radioactive decay of 14CPrinciple of dating through 14C
14C is present in atmosphere
(equilibrium concentration: disappears by radioactive
decay but is continuos produced by cosmic rays)
Through various methabolic mechanisms,
ALL LIVING ORGANISMS PARTICIPATE IN THIS
EQUILIBRIUM
and have therefore the same 14C concentration
UNTIL LIVINGPrinciple of dating through 14C
photosynthesis
food chainPrinciple of dating through 14C
Starting from the death of the organism, the
radioactive decay of 14C is no more
compensated by any uptake; thus, its
concentration decreases continuouslyPrinciple of dating through 14C
· 10-12
1,2
14R(t) = 14R0 · e –t/t
1
with 14R0 = 1.18 10-12 and t = 8266 y
R (14concentration
C/12C ratio)
0,8
t = t · ln [14R0 / 14R(t)]
0,6
0,4
C-14
14
0,2
0
0 10000 20000 30000 40000
time from death (years)14C dating
Also nuclear are the techniques for measuring
14C residual concentrations:
the now dominant technology is
Accelerator Mass Spectrometry (AMS)The challenge of AMS
Attaining a huge sensitivity
still keeping high precision
Indeed, ultra-low 14C concentrations (down to 10-15) must
be measured with
small uncertainty
(e.g.: 0.5% error on concentration 40 years on age)
Accelerator Mass Spectrometry can do that
.. without destroying significant quantities of the find (few
milligrams, or even less, are sufficient)Measuring 14C with AMS
Stripping at HV terminal
(eliminates interference
of 13CH, 12CH2)
Tandem accelerator
Analysis and
detection systems
Multi-sample
source
Negative ion source Magnetic + electrostatic analysis +
(eliminates interference detection systems of high energy ions
of 14N) (remove residual interferences)39
40
Examples of dating at
LABEC
41St. Francis’ relics from
Cortona and from the
Basilica of Santa Croce
in Florence
Archaeological excavations
of Etruscan sites
River sediments – Abak Creek in Etiopia
Excavations of medieval sites
in downtown Florence
(Palazzo Vecchio and 42
Biblioteca Magliabechiana)Artemidorus papyrus
The frame of a tryptic by
Ambrogio Lorenzetti
The Rosano Crucifix44
Exploiting the effect of nuclear explosions
in atmosphere during the cold war
200
of Modern Carbon)
190
Reference curve for the
180
Boreal Emisphere
170
160
150
pMC (percent pMC
140
130
120
110
100
90
1940 1950 1960 1970 1980 1990 2000
year AD 45Many intersting applications in forensics
and biology,
but these rapid variations can also be
used to discover recent fakes of
contemporary art e.g. from the first
half of the XX century
46Samples of fine paper produced in different
years
220
Fine paper samples
200 Bomb04NH1
14C conc. (pMC)
180
160
140
120
100
1940 1950 1960 1970 1980 1990 2000
Anno
The date found must be compatible with at least one date prior to
productionCanvas samples from dated paintings
217
Tele
Bomb04NH1
197
14C conc. (pMC)
177
157
137
117
97
1900 1920 1940 1960 1980 2000
Year reported
Annoon the paintingBut...if the painting support is only compatible with a later period...
But...if the painting support is only
compatible with a later period...
A canvas sample from a painting
initially attributed to Fernand Legér
200
190
180 129.05 ± 0.68
170
pMC
160
150
pMC
140
130
120
110
100
90
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
year ADNot only accelerator-based
techniques among nuclear
techniques at LABEC
Developed an innovative XRF
transportable system
for certain aspects, approaching the performance of
IBA techniquesThe new portable XRF spectrometre
● independent PS for the two
tubes
● He bottle
● acquisition, He flow, x-y
translations and camera are remotely
Ethernet-controlled by the same
computer
Controller
Measuring head
● 2 X tubes (30 kV max, 500 mA max) with
different anodes (typically Mo and Ti; W if needed)
● interchangeable collimators; typical X
ray beam diametre 1 mm
● SDD X ray detector (10 mm2 active area, 450
μmthickness, FWHM 139 eV @ 5.9 keV)
● helium flow in front of both X ray tubes and
detector
● 2 lasers for accurate
positioning
● viewing cameraUsing this portable XRF....
UltramarineStesura
blue oltremare
ultramarine
layer on aartificiale
blue layer preparation
chalk
6000
Si
5000
4000
conteggi
3000 S (+Mo)
Al
2000
Ca
1000
Na K Ca Fe
0
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
energia (eV)
Mo 22kVAffresco della
Resurrezione
Piero della Francesca
Sansepolcro,
Museo Civico
5455
Crucifix, Maestro di Figline
Santa Croce
56Santa Croce, Cappella Bardi –
cycle of frescoes by Giotto
57Madonna del Granduca
Raffaello
Galleria Palatina
58La Chimera di Arezzo
Museo Archeologico
Firenze
59Beato Angelico, Crocifissione Capitolare, San Marco, Firenze
Thank you
mando@fi.infn.itYou can also read
