The Invisible technology

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The “Invisible” technology

A new method for anti-counterfeiting in the cultural heritage field

Marco Peloi, Luca Gregoratti, Giuseppina Palma

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Marco Peloi – SIF – 27 September 2013 |

“Invisible” technology

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Elettra – Sincrotrone Trieste has developed an anti-counterfeiting technology based on optical

properties of microscopic

fluorescent particles, activated using a focused synchrotron light beam.

Using these particles it is possible to make anti-counterfeiting marks, visible only when enlightened by a specific wavelength.

Patents: PCT/EP2008/051320 filed 4/02/2008 PCT/EP2010/070096 filed 17/12/2010

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Elettra Sincrotrone Trieste

Who we are

No profit shareholder company recognized of national interest.

Shareholders:

Area Science Park,

Friuli Venezia Giulia Region,

CNR,

Invitalia.

Established 27 years ago to build and manage synchrotron light

sources to be open internationally.

What we do

The mission is to promote cultural, social and economic growth

through basic and applied research in relevant fields,

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Marco Peloi – SIF – 27 September 2013 | 5

Elettra at a glance



400 employees



100000 m

2



5000 hours /year



34 beamlines



more than 1000 Users

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A powerful light source

Booster Storage Ring Beamline Measurement station

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Marco Peloi – SIF – 27 September 2013 | 7

Synchrotron light properties

High brilliance

Wavelength tunability

Coherent and collimated light

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Color Centers

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• A color center (CC) is a defect in a crystalline structure in which a

vacancy is filled by one or more electrons and are characterized by their absorption and emission bands . • CC could be generated by ionizing

radiation such as Synchrotron Radiation.

• In LiF the more relevant CC are F₂ and F₃+

• If LiF CC are illuminated by an

appropriate (~ 450 nm) radiation, they fluoresce and emit light in the visible region (R=648 nm, G=541 nm) of the electromagnetic spectrum.

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ESCA Microscopy

• Linearly Polarised Undulator

• Photon energy range: 350 – 1200 eV • SGM monochromator equipped with 2 gratings for low and high photon energy • Zone Plate

• Beam size =135 nm (SPEM)

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LiF Fluorescent Grating…

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• 0.3 μm tickness LiF film • Si substrate

• Beam spot size up to ≈130 nm • exposure time 100 ms

• Flux = 2x1018_{photons / cm}2 _s _3.5 μm

…. and many other patterns using stepper and piezo driven motors with 1 μm and 10 nm accuracy.

FWHM 800 nm

“Luminescent nanostructures based on colour centres produced in LiF films by direct writing with an X-ray microprobe”, phys. stat. sol. (c) 2, No. 1, 298 – 301 (2005)

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How to see fluorescence

Fluorescent light can be observed using a 450 nm wavelength light, produced

by low cost lighting device

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Different excitation source /

different emission spectra

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CC produced using synchrotron radiation have a characteristic spectrum that cannot be produced using other activation methods.

Comparison between two emission spectra of CC obtained using synchrotron radiation (blue curve) and an electron source (red curve).

The blue curve is typical of Synchrotron light activated CC.

synchrotron radiation

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Different excitation flux /

different emission spectra

Synchrotron Radiation Excitation leads to different spectra depending on the radiation flux.

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How to use these features

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Using an optical fiber mounted on a xy scanner and connected to a spectrometer that excites fluorescence and collects

emitted light it is possible to map the drawing on green and red channels separately

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Different flux / different green

shades

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Features

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 Invisible labels or marks fluoresce under visible light when excited with blue light produced by low cost lighting device (first level of security).

 The activation process of LiF films can be made in different ways, each

producing a specific fluorescence spectrum that can be observed either with portable medium cost analytical tools or directly in a central laboratory to serve as central service (second level of security).

 LiF films activated using Synchrotron radiation have a characteristic

spectrum that can be produced only in similar laboratories (<20 in the world). This feature helps to certify the origin of the particles used to produce marks or labels (third level of security).

Promising technology for anti-counterfeiting but …

… all marks are to be made @ Elettra

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Solution… pigment for inks

LiF crystalline powder

Synchrotron light activation (@ Elettra)

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How to apply the technique

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The CC can be produced (activation process) in a powder of small crystals and applied to several support surfaces and in several ways.

Some of these methods are listed below:

 Evaporation. Microscopic particles can be evaporated on a surface forming a thin

film with a thickness of few tens of nanometers on almost all substrates and the mark can be generated by using a narrow beam of electrons or synchrotron light.

 Printing. Activated particles can be used as a component of ink or paint. Inks or paints can be applied on many substrates through the standard printing techniques such as flexography, inkjet, … or applied directly using stamps, airbrush and

paintbrushes.

 Mixing. Activated particles can be mixed with other components like glue, and used

to fix tags on products. The simple presence in the glue of a fluorescent component guarantees the authenticity of the tag.

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Applications

Industrial

ID field, Fashion, Banking industry, …

Custom

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Cultural Heritage

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During 2005-2006 the Italian Guardia di Finanza has retrived 16,352

specimens of archaeological interest and 972 paintings. During this

period 332,158 counterfeit works have been seized.

According to the FBI the market of works of art is second only to drug

trade in terms of turnover and in the United States "moves" 64 billion

dollars a year.

A resesearch of the University of Washington

and the University of

California has established that 91% of the sculptures and drawings of

artists Henry Moore and Alexander Calder for sale on Ebay are fake.

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Cultural Heritage

Standard techniques use visible

marks or tags associated to the

objects.

They are visible and easily

reproducible eve by counterfeters

Coins. Since visible marks are too

invasive, coins are usually placed in

a sealed envelope, together with the

documents of authenticity.

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Application with airbrush

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The activated powder is mixed with other components to produce an ink

that can be applied using a airbrush and a mask in which is impressed the

code or the logo to be placed on artwork.

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Example #1: ancient coins

Ancient coin marked with activated particles, observed under natural light (a) and an blue source (b). Detail of the surface of the coin showing the

fluorescent writing (c). Each character is 0.5 millimeter large.

a) b) c)

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Example #2

Tesoretto Celtico di Manerbio

25 In cooperation with the “Comune di Brescia - Servizio collezioni e aree archeologiche”

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Example #3: Lithographic print

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Giambattista Tiepolo

“Due maghi e un bambino” Acquaforte, sec. XVIII

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Mark applied with a stamp

Ascanio di Brazzà –Drawing “testa di bue”, sex XIX

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Example #4: painting (front)

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Observed under natural light

Observed using blue light

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Example #5: painting (back)

Stamp applied to the back of a painting, on the wooden frame (a-b) and on canvas (c)

In cooperation with the “Comune di Udine - Musei Civici”

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Other Applications

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Many other tests have been carried out on different materials: ceramic pots,

canvas for paintings and plaster statues.

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Summary of Mark Features

 Labels or marks are invisible if observed under normal lighting but visible (and their authenticity can be verified) when excited with blue light

produced by low cost lighting device (first level of security).

 The activation process of the microscopic particles can be made in

different ways, each producing a specific fluorescence spectrum that can be observed either with portable medium cost analytical tools or directly in a dedicated laboratory to serve as central service (second level of

security).

 Particles activated using Synchrotron radiation have a characteristic

spectrum that can be produced only in similar laboratories (< 20 in the world). This feature helps to certify the origin of the particles used to produce marks or labels (third level of security).

 Synchrotron radiation activated powder could be produced at a relatively low cost.

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Acknowledgements

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Researchers involved in the development of this technique:

Luca Gregoratti Giusy Palma

Matteo Maria Dalmiglio Annalisa Boscaino Marco Peloi

Elettra – Sincrotrone Trieste

Marija Kosec

Danjela Kuscer Hrovatin

Jozef Stefan Institute - Ljubljana

Raffaela Rimaboschi

Art Conservation

The activity has been done in cooperation with:

AREA Science Park - Progetto Sister

Soprintendenza per i Beni Archeologici del Friuli Venezia Giulia Comune di Udine - Musei Civici

Comune di Brescia - Settore Musei, Cultura e Turismo

Soprintendenza per i beni archeologici del Friuli Venezia Giulia

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