Photodetectors atPhotodetectors at «« Le LouvreLe Louvre »»XX--ray, ray, γγ--rayray andand visible visible spectrometries spectrometries

appliedapplied to to Art Art and Archaeologyand Archaeology issues issues

T. Calligaro, Centre de recherche et de restauration des musées de France

UMR 171 – Palais du Louvre

New Developments in Photodetection, June 21, 2002

Outline•• PresentationPresentation of of the the C2RMF C2RMF •• Examination Examination of of artifactsartifacts

•• Visible light, IR Visible light, IR reflectographyreflectography, UV fluorescence XR , UV fluorescence XR imagingimaging•• examplesexamples of application to of application to examinationexamination ofof paintingspaintings and and sculpturessculptures

•• Characterisation Characterisation of of materialsmaterials•• Introduction to Introduction to acceleratoraccelerator--based methods based methods •• Example Example of of detection detection of of fakes using chemical fakes using chemical compositioncomposition•• Example Example of of materials materials identification identification and determinationand determination of of

provenanceprovenance

•• Specific problemsSpecific problems•• Improvement Improvement of of the sensitivity the sensitivity to trace to trace elementselements•• Chemical environment with Chemical environment with HiHi--Res Res XX--ray ray spectrometryspectrometry•• Portable Portable detection systems detection systems for for onon--the fieldthe field analysisanalysis

Conclusions Conclusions and and prospectsprospects

Presentation of the Center for research and restoration of the

museums of France (C2RMF)

Belongs to the French Ministry of Culture Created in 1999 by the merging

of the laboratory and restoration centre

Laboratory

Founded in 1931 by 2 Argentinean physicians

Located in Paris under the Carrousel gardens of the Louvre

Staff ~70 : Culture (curators, engineers), CNRS, CEA

Associated with CNRS since 1996 – UMR 171

Location of the C2RMF

Missions of Missions of thethe C2RMFC2RMF

Diagnosis, short studies on art and archaeology works• acquisition (authentication)• restoration • exhibition

Long-term research• archaeometry : studies of ancient technologies and provenance• conservation science : understanding the artists techniques• preventive conservation : investigation of alteration process

Publishing and teaching

Main tools for examination and characterisation of cultural heritage

•• ExaminationExamination of of artifactsartifacts•• Visible light, IR Visible light, IR reflectographyreflectography, UV fluorescence , UV fluorescence •• XX--ray ray imagingimaging, , betagraphybetagraphy, , emissiographyemissiography•• Scanning Scanning electronelectron microscope (SEM)microscope (SEM) imagingimaging

•• Characterisation Characterisation of of materialsmaterials•• Structural Structural analysisanalysis : XRD, FT: XRD, FT--IR, Raman IR, Raman •• Inorganic chemical Inorganic chemical composition : IBA, XRF, SEMcomposition : IBA, XRF, SEM--EDXEDX•• OrganicOrganic composition :composition : ChromatographyChromatography, GC, GC--MSMS

•• DatingDating•• ThermoluminescenceThermoluminescence•• 1414C C using acceleratorusing accelerator--based based mass mass spectrometryspectrometry

ExaminationExamination of of works works of artof art

Paintings and Paintings and sculpturessculptures

Photography with direct and grazing light:evidence of the Van Gogh’s technique

in « Mademoiselle Gachet au jardin »

Ven

usG

enitr

ix1st

-2nd

AD

visible light ultraviolet

Venus Genitrix (detail)restored hand made in a different marble

Principle of infrared reflectography :access to the charcoal underdrawing

mid-rangeinfrared(1.8-2.5µm)

Raphael’s painting

Examination by infrared reflectography

Radiography studio for paintings

Radiography of the « Gobeur d’oursins » of Picasso (1946):painted on top of a portrait of Gal Vanderberg

Radiography

Examination of a Spanish painting from the XVIth centurydirect light grazing light

Spanish painting : UV fluorescence reveals restorations

visible light ultraviolet

Spanish painting :X-rays reveals a second character : part of a wider composition

Infrared Radiography

AnalysisAnalysis ofof material usingmaterial usingnonnon--destructive techniques:destructive techniques:

thethe case ofcase of acceleratoraccelerator--based methodsbased methods

Fundamentals Fundamentals of PIXE et PIGE of PIXE et PIGE methodsmethods((PParticlearticle IInducednduced XX--rayray EEmissionmission et et PParticlearticle IInducednduced γγ--rayray EEmissionmission ))

XX--rays rays γγ--r

ays

rays

Beryllium : 9Be(p,αγ)6Li 3562 keV

Lithium : 7Li(p,p’γ)7Li 477 keV

Fluorine : 19F(p,p’γ)19F 197 keVtarget atomstarget atoms

e-expelled electronexpelled electron

33--MeV MeV protonsprotons

acceleratoraccelerator

HPGe HPGe detectordetector Si(Li) Si(Li) detector detector

AAccelerateur ccelerateur GGrand rand LLouvre pour l’ouvre pour l’AAnalyse nalyse EElémentairelémentaire

22--MV tandemMV tandem acceleratoraccelerator«« AGLAEAGLAE »»

Control Control andand datadataacquisistionacquisistion roomroom

PIXE PIXE external beam setup and experimentalexternal beam setup and experimental conditionsconditionsProton Proton energyenergy : 3 : 3 MeVMeVBeam intensityBeam intensity : 2 nA: 2 nA

integratedintegrated dosedose : 0,25 : 0,25 µµC C --> no damage> no damagebeam diameter beam diameter on on the targetthe target : 20 : 20 µµmmbeambeam exit foil : 0.1 exit foil : 0.1 µµm m silicon nitridesilicon nitride

sample

L

H

�

�

He flow«« low energylow energy »»

L L --detectordetector«« high energyhigh energy »»

H H -- detector detector entranceentrancewindowwindow

0.25 0.25 µµmm boron boron nitridenitride

6 6 µµmm BeBe

absorberabsorber 1 1 µµmm carboncarbonHe atmosphereHe atmosphere

100 100 µµmmaluminumaluminum

energyenergy rangerange 0,6 0,6 -- 20 20 keVkeV 5 5 -- 4040 keVkeV

elementelementrangerange

matrixmatrixoxygenoxygen--ironiron

tracetrace elementselementscalciumcalcium--yttriumyttrium

solidsolid angleangle 1 1 msrmsr 100100 msrmsr

CloseClose--up of up of the external beam the external beam systemsystem

Target : Target : gemstonegemstone

Low energyLow energy XX--ray ray detector detector for major for major elementselements e.g. Al, Si…e.g. Al, Si…

HighHigh energyenergy XX--ray ray detector detector for trace for trace elementselements e.g. e.g. CrCr, , TiTi, V, , V, FeFe, , GaGa……

HPGeHPGeγγ--ray ray detectordetector

Helium Helium fluxflux

videovideo cameracamera

Charged particle Charged particle beam beam exitexit

Main Main featuresfeatures of of acceleratoraccelerator--based methodsbased methodsBenefitsBenefits•• non destructive non destructive analysisanalysis of of objects with any shape and objects with any shape and sizesize•• no no samplingsampling, no , no preparationpreparation ((conductiveconductive coatingcoating etc.)etc.)•• simultaneous measurement simultaneous measurement of a of a wide wide range of range of elementselements (10< Z < 92)(10< Z < 92)•• sensistivity sensistivity to trace to trace elementselements (down to (down to thethe µg/g µg/g levellevel))•• 30 µm30 µm33 probedprobed volume: volume: selectionselection of of detailsdetails•• truly truly quantitative quantitative methodsmethods•• elemental mapselemental maps (micro et (micro et macroscopicmacroscopic scalescale))

DisadvantagesDisadvantages•• no information about no information about thethe chemical chemical statestate•• no structural information (XRD, IR, Raman)no structural information (XRD, IR, Raman)•• nearnear surface (1 surface (1 –– 30 µm) (30 µm) (problems with altered objectsproblems with altered objects) ) •• expensive expensive large large scale facilityscale facility

First First application of application of thethe PIXE PIXE method method : : Indirect Indirect dating dating of of paintingspaintings

The The portrait of Bernard Palissyportrait of Bernard PalissyPainting suppossedly Painting suppossedly representing representing B. B. Palissy, French Palissy, French scientist and artist scientist and artist of of the the RenaissanceRenaissance

(1580(1580--1620)1620)

Proposed Proposed to to be be acquiredacquired by by the the French French museumsmuseums

First First application of application of thethe PIXE PIXE method method : : detectiondetection of of forgeriesforgeries

PresencePresence of CrPbOof CrPbO44 green pigment green pigment only introducedonly introduced after after 18501850

This This painting is probablypainting is probably a a forgeryforgery

Application of Application of thethe PIXE PIXE method method : : materialsmaterials identification identification and and provenanceprovenance

Ishtar’s eyesIshtar’s eyesStatuette Statuette exhibited exhibited in in thethe Louvre Louvre museummuseumDatedDated toto the Parthian periodthe Parthian period (1(1stst BC BC –– 22nd nd AD)AD)

LikelyLikely representingrepresenting Ishtar, Ishtar, the famous mesopotamian the famous mesopotamian mother goddessmother goddess

(Astarté or Venus)(Astarté or Venus)

DiscoveredDiscovered in 1863 in in 1863 in thethevicinityvicinity of of BabylonBabylon

The statuette is placed in the external beam system

PIXE PIXE spectra recorded spectra recorded on one on one eyeeye

X-ray energy (keV)

coun

ts

1

10

100

1000

10000

1e5

0 5 10 15 20 25

high energy X-ray detector spectrum

low energy X-ray detector spectrum

OK

Al K

Ti K V K CrK Fe K

Ga K

SriLankIndia 1

India 2

Burma

Cambodia

Thailand

Afghanistan

VietNam

Babylon

Map of Middle East and Asia : sources of rubies

Sri Lanka

Trace Trace element fingerprint element fingerprint of of rubies from rubies from Ishtar Ishtar and various depositsand various deposits

Iron(ppm)

Chr

omiu

m (p

pm) T T TTT

TT

TT

TT

T

TTT

V

V

VV

V

VVV

V

VV

KKKK

KK

MM

MM

MM

MM

MM

MM

MM

MM

M M

MM

B BB

B B

B

B

B

B BBB

B

B

B

BB

B

B

B

B

BB

B

B BB

B

B

B

BB

B

B BB

BB

B

BBB

BBB

B

BBB B

B

BBB

BBB

BBB BBB

B

BB B BBB

BB

B

BB

B

BB

BBB

B

B

B

BB B

BB

B BB

B

BB

B

BB B

BBBB

B

B

BBBBB

BB

B

B

B

B

BBBB BBB

BB B

BB B

BBBBB

BBBBB B B

BBBBBB

BBBBB B

BB B

B BB BB

BBBB

BB

B

BBBBB BB BB BBB

B

B

B

B B

B

B

B

B

BB

A

A

AA

A

A AA

AAA

A AAB

BB

TT

TC CCVVV

SS

S

MMM

II

II

II

I

II

III

BB

BBB

B

B

B

BB

B

B

BB

B

B

B

X XX

XB

XX

XX

SSSSSS

SS

SS

SS

S

S

SSS

S

SS

SS

SSS

SS

S SS

S

S

S SS

S

SS S

SS

SS

S

SSS

S

S

S

S

SS

S

SSS

S

S

S

S

SS

B

T

10

100

1000

10000

10 100 1000 10000

Statuette of Ishtar

group IBurmaVietnam A

group IIAfghanistanSriLankaVietnam B

group IIIThailandCambodiaKenyaMadagascarIndia

Proof of Proof of authenticityauthenticity of of the the statuettestatuette

Original report of Mr P. Original report of Mr P. DelaporteDelaporte, French consul , French consul at at BagdadBagdad

who discovered thewho discovered the statuettestatuetteDocument Document written at Hillahwritten at Hillah, , close to close to BabylonBabylon

JanuaryJanuary 21, 186321, 1863

Results

The eyes and the navel of Ishtar are not made of red glass, nor red garnets, as previously reported, but rather proved to be fine rubies.

According to the age of the statuette, this is the most ancient rubies found in Middle-East.

Evidence of a gem route between South-East Asiaand Mesopotamia during the 1st century BC.

The jewelsThe jewels ofof the first the first kingskings of Franceof France

SaintSaint--DenisDenis BasilicaBasilica ((northnorth of Paris)of Paris)cemetarycemetary ofof the kingsthe kings of Franceof France

since the Merowingiansince the Merowingian

paire of brooches 450-500 A.D

plaque-boucle 470-500 A.D

plaque « bull » 480-510 A.D

5-digits brooch~500 A.D

pair of brooch

500-520 A.D

2 disc brooches« reine Aregonde »

575-600 A.D

Quatrefoil brooch600-625 A.D

2 square brooches 500-550 A.D

TheThe garnetsgarnets

H = 6½ - 8½r = 3.5 - 4.3 g.cm-3

n = 1.78 - 1.89

Chemical composition of garnets A3

++B2+++ (SiO4)3

end-members

grossularAlCaouvaroviteCrCaandraditeFeCa

spessartiteAlMnpyropeAlMg

almandineAlFe

Actually garnets are a solide solution of end membersexample :

rhodolite = mixing of 50% pyrope / 50% almandin

Fe/Mg plot : three groups of garnets

Mg vs Fe

Fe (ppm)

Mg

(ppm

)

0

20000

40000

60000

80000

1e5

1,2e5

1,4e5

1,6e5

1,8e5

0 60000 1,2e5 1,8e5 2,4e5 3e5 3,6e5

Pyropes

Rhodolites

Almandins

Ca/Mg plot : 2 types of almandines

othersquatrefoil5 fingers brooch

MgO (ppm)

CaO

(ppm

)

0

10000

20000

30000

40000

50000

60000

70000

10000 30000 50000 70000 90000 1,1e5 1,3e5 1,5e5 1,7e5 1,9e5

almandines :

pyropes :types IV & V

rhodolites :type III

type I

type II

othersquatrefoil5 fingers brooch

MgO (ppm)

CaO

(ppm

)

0

10000

20000

30000

40000

50000

60000

70000

10000 30000 50000 70000 90000 1,1e5 1,3e5 1,5e5 1,7e5 1,9e5

almandines :

pyropes :types IV & V

rhodolites :type III

type I

type II

Yttrium content confirms 2 sources of almandines

eagle A5 fingerseagle Bbullquatrefoilkidneysquare Bsquare A3 fingers A3 fingers BArégonde AArégonde B

Magnesium (ppm)

Yttri

um (p

pm)

-100

100

300

500

700

900

1100

1300

0 40000 80000 120000 160000

type II

type I

type III

type IVtype V

Scattered content in yttrium : macroscopic zoning

Comparison with published data on garnets: Quast & Schlüsser 2000 (SEM-EDX)

Results

The garnets set on the Merowingian jewels were extracted from India and Sri Lanka

Evidence of two sources indian deposits

Coming from the East during the great Invasions, the first Frankish kings have kept their sources oriental ofgarnets

On the latest jewels (7th century), the type of garnetschanges: pyropes from Bohemia

Surprisingly from the 5th to the 7th century AD, the Barbarians have established a gem route to Asia.

study of provenance of gold used in Merowingian jewellery

The key feature for improving the limit of detection is the Peak/Background ratio of X-ray detectors

The interesting trace element are the Platinum Group elements (Ru, Rh, Pd, Os, Ir, Pt and Sn Sb . Typical content is 100 µg/g. The related lines lie in the 20 keV-range. Pt has its lines just underneath the Au lines at 9.44 keV

PIXE spectrum on the brooch

The interesting trace element : Platinum Group elements : (Ru, Rh, Pd, Pt, Os, Ir) and Sn Sb .

Typical content is 100 µg/g

The related lines lie in the 20 keV-range. Pt has its lines just underneath the Au lines at 9.44 keV

Improve manufacturing technology (reduce charge collection loss)

reduce shaping time / use digital pulse processor in order to reduce sum peaks

Hi-res spectrometry for chemical speciation

Chemical state (valence) accessible by means of X-ray satellite peaks resulting of bombardment withheavy particle (multiple shell ionization).

WDS ?

µ-Calorimeter ?

development of a portable XRF system for on the field analysis(museum, archaeological site…)

Peltier-cooled Si-drift diode300-µm crystal thickness: efficiency drops above 10 keVageing problemspoor peak/background ratio

Conclusion

The photon probe, due its non-destructive character, is recognised as a valuable tool for study of art and acheological artifacts

The study of cultural heritage will benefit from developments in photodetectors

Encouraging prospects

Good old Mona Lisa…

investigated using a state of the art detector…

…and with a new generation photodetector