The Invisible technology

Transcription

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2 The Invisible technology A new method for anti-counterfeiting in the cultural heritage field Marco Peloi, Luca Gregoratti, Giuseppina Palma Elettra Sincrotrone Trieste 2

3 Invisible technology 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/ filed 4/02/2008 PCT/EP2010/ filed 17/12/2010 3

4 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, technical and scientific training, and technology transfer. 4

5 Elettra at a glance 400 employees m hours /year 34 beamlines more than 1000 Users from more than 50 countries 5

6 A powerful light source Storage Ring Booster Measurement station Beamline 6

7 Synchrotron light properties High brilliance Wavelength tunability Coherent and collimated light Elettra 7

8 The beginning 8

9 Color Centers 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 F 2 and F 3 + 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. 9

10 ESCA Microscopy scanning photoemission microscope Linearly Polarised Undulator Photon energy range: ev SGM monochromator equipped with 2 gratings for low and high photon energy Zone Plate Beam size =135 nm (SPEM) 10

11 LiF Fluorescent Grating 0.3 μm tickness LiF film Si substrate Beam spot size up to 130 nm exposure time 100 ms Flux = 2x10 18 photons / cm 2 s. and many other patterns using stepper and piezo driven motors with 1 μm and 10 nm accuracy. 3.5 μm 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, (2005) 11

12 How to see fluorescence Fluorescent light can be observed using a 450 nm wavelength light, produced by low cost lighting device 12

13 Different excitation source / different emission spectra 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 electron source synchrotron radiation

14 Different excitation flux / different emission spectra Synchrotron Radiation Excitation leads to different spectra depending on the radiation flux. 14

15 How to use these features Scanning fluorescence spectrometer 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 15

16 Different flux / different green shades Synchrotron Radiation Excitation 16

17 Features 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 Elettra 17

18 Solution pigment for inks LiF crystalline powder Activated pigment for Inks Synchrotron light activation Elettra) 18

19 How to apply the technique 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. 19

20 Applications Industrial ID field, Fashion, Banking industry, Custom Cultural Heritage, Small security projects 20

21 Cultural Heritage During 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. 21

22 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. 22

23 Application with airbrush 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. 23

24 Example #1: ancient coins a) b) c) 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. In cooperation with the Soprintendenza per i Beni Archeologici del Friuli Venezia Giulia 24

25 Example #2 Tesoretto Celtico di Manerbio In cooperation with the Comune di Brescia - Servizio collezioni e aree archeologiche 25

26 Official agreements 26

27 Example #3: Lithographic print Giambattista Tiepolo Due maghi e un bambino Acquaforte, sec. XVIII In cooperation with the Comune di Udine - Musei Civici 27

28 Mark applied with a stamp Ascanio di Brazzà Drawing testa di bue, sex XIX In cooperation with the Comune di Udine - Musei Civici 28

29 Example #4: painting (front) Observed under natural light Observed using blue light 29

30 Example #5: painting (back) a) b) c) 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 30

31 Other Applications Many other tests have been carried out on different materials: ceramic pots, canvas for paintings and plaster statues. 31

32 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. 32

33 Acknowledgements 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: Soprintendenza per i beni archeologici del Friuli Venezia Giulia 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 33

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