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Outline

ANCIENT CHARM A new project for neutron-based 3D imaging with applications to cultural heritage research G. Gorini on behalf of the Ancient Charm collaboration. Outline. ANCIENT CHARM State of the art Project objectives and plans. ANCIENT CHARM. ANCIENT CHARM. C ultural H eritage and

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Outline

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  1. ANCIENT CHARMA new project for neutron-based 3D imagingwith applications to cultural heritage researchG. Gorinion behalf of the Ancient Charm collaboration G.Gorini

  2. Outline ANCIENT CHARM State of the art Project objectives and plans G.Gorini

  3. ANCIENT CHARM G.Gorini

  4. ANCIENT CHARM Cultural Heritage and Archaeological Research Methods Analysis by Neutron resonant Capture Imaging and other Emerging Neutron Techniques:new EU funded ADVENTURE project under the New and Emerging Science and Technology (NEST) programme of FP6. Expected start date: 01/2006. Duration: 36 months G.Gorini

  5. Aim of ANCIENT CHARM “To provide a new, comprehensive neutron-based imaging approach, which will be applied here for the 3D imaging of elemental and phase composition of objects selected as a result of a broad scope archaeological research.” G.Gorini

  6. The ANCIENT CHARM Collaboration A mix of expertise in neutron instrumentation and archaeology G.Gorini

  7. Available neutron sources NIPS, Budapest (reactor) PGAA in regular use @ 107 n/cm2s Recently awarded a national grant to renew instrumentation. Expected increase of the neutron flux: factor or 5. FRM-II, Garching (reactor) NT+PGAA beamline available in 2007 @ 109 n/cm2 GELINA, Geel (150 MeV LINAC, pulsed) NRCA in regular use ISIS, Chilton (800 MeV p beam, pulsed) ND systems in regular use. Provides highest flux of epithermal neutrons. G.Gorini

  8. PGA beam line at the new research reactor FRM-II, Garching, Germany Experimental hall Neutron guide hall The new PGA and cold neutron tomography station Neutron flux ~ 1.5 – 6 109 cm-2 s-1 Initial beam size = 5 cm x 11.5 cm Available in 2007 FRM-II 20 MW reactor 2.03.2004 First time critical G.Gorini

  9. The ISIS Facility G.Gorini

  10. Neutrons and Cultural Heritage Research • A large variety of chemical, physical and microstructural techniques • are employed to characterize objects of cultural significance. • Most of these methods are invasive. • Probes like X-rays and charged particles have limited penetration. • Neutrons penetrate thick layers depending on their energy. • Use neutrons for quantitative, non-invasive analysis in bulk. • Neutron-based techniques: a recent development (exception: INAA). G.Gorini

  11. E g Neutron Capture Resonances Neutron Energy NRCA PGAA Cross section E T1/2 (I)NAA G.Gorini

  12. Neutrons-based techniques Neutron Radiography/Tomography (widespread)- similar to CT-3D images Neutron Diffraction (widespread)-mainly structural analysis-2D Prompt Gamma Activation Analysis (a few places)-elemental analysis-0D Neutron Resonant Capture Analysis (GELINA)-elemental analysis-0D G.Gorini

  13. STATE OF THE ART G.Gorini

  14. Cold Neutron Tomography G.Gorini

  15. Radiograph Sample Radiation source Cold Neutron Tomography Measurement Analysis : Back-projection G.Gorini

  16. Detection system Sample Beam xyz translation rotation table Table CCD Lead glass Mirror 12 bit CCD SensiCam camera Pixel size : 6.7  6.7 mm2 Number of pixels : 1280  1024 Readout Time : 8 fps Pb + 6LiF Field of view : 2.7 mm x 3.4 mm Image size : 640 x 512 Effective pixel size = 54 mm Typical exposure time ~ 2 s Binning 2x2 Conversion screen 420 mm-thick ZnS(Ag) / 6LiF with Al backing 100 mm-thick ZnS(Ag) / 6LiF G.Gorini

  17. Application in Aerospace Industry Quality-control of pyrotechnic cutters used in space programs (Ariane) Computer assisted inspection G.Gorini

  18. beam dimensions Neutron focusing lens PSI: Kumakhov capillary-based neutron lens: entrance height: 50mm entrance width: 20mm length: 155mm focal distance: 150mm focus at FWHM: 0.7mm max. gain on the spot: 16 FRM II: Polycapillary bending and focusing lens: entrance height: 45mm entrance width: 50mm length: 190mm focal distance: ~95mm focus: ~0.65mm gain on the spot:~20 new spot: 20mm bellow the incoming beam G.Gorini

  19. Neutron Diffraction G.Gorini

  20. GEM G.Gorini

  21. ENGIN-X G.Gorini

  22. The ENGIN-X transmission detector Hamamatsu 16 channel position sensitive PMTs Fibre light guides GS20 Glass scintillator pixels Efficiency 85% at 1Å Pixel array 10 x 10 Pixel size 2 mm x 2 mm on 2.5 mm pitch Count rate 106 per PMT ie or 64 mm2 100 element transmission detector for residual stress measurements G.Gorini

  23. Neutron transmission and Bragg edges Incident spectrum Pulsed neutron source Transmitted spectrum Sample (r, A) x Pixelated detector G.Gorini

  24. Strain around a cold expanded hole G.Gorini

  25. Prompt Gamma Activation Analysis G.Gorini

  26. The NIPS experimental station G.Gorini

  27. Sensitivities at the PGAA-NIPS facility G.Gorini

  28. Neutron beam 1 mm Pilot experiment for imaging Cu SiO2 HPGe detector G.Gorini

  29. Neutron ResonantCapture Analysis G.Gorini

  30. NRCA on a prehistoric bronze axe G.Gorini

  31. PGAA c thermal capture cross section  branching  detection efficiency a atomic abundance NRCA A,r resonance area 1/Er flux shape Comparison: NRCA vs. PGAA G.Gorini

  32. PGAA (at Budapest) and NRCA (GELINA) Accuracy for Cu in a bronze artefact about 1% PGAA <----> NRCA  ko and Sr relative to Cu PGAA best for light elements • H, S, P, and K NRCA best for heavy elements • As, Ag, Sb, Sn, Au and Pb G.Gorini

  33. Pilot NRCA tests on ISIS Small YAP detector Threshold: ≈0.6 MeV G.Gorini

  34. PROJECT OBJECTIVESAND PLANS G.Gorini

  35. G.Gorini

  36. From NRCA to NRCI/NRT • Spatially resolved information: combination of • -tight neutron beam collimation, • -multiple positioning of the sample, • -simultaneous measurement of neutron resonances with different strengths. • => “Neutron Resonant Capture Imaging” combined with “Neutron Resonance Transmission” (NRCI/NRT): • Transmission and measurements simultaneously. • Use YAP crystals for  detection. • Produce images using a few resonances. G.Gorini

  37. 400 mm YAP Crystal detectors 400 mm Boron collimator Transmission detector XYZ- stage Li (or B) cladding G.Gorini

  38. Transmission vs. measurements •  measurements • Requires a small beam. • Produces cord-integrated 0-D points. • Need to scan in 3 D (YZ) • Contrast is produced by the intensity of the  peak. •  background is an issue. • Has problems at low concentrations if background is high. • Transmission • Requires good angular collimation and a large beam. • Produce 2D images directly (like neutron tomography) • Need to scan in 1 dimension () • Contrast is produced using the depth of the resonant absorption. • Neutron and  background not an issue. • Has problems with very diluted and very concentrated systems. G.Gorini

  39. A 2D NRT detector • Experience on existing detectors at ISIS • Engin-X 2D transmission monitor: 100 pixels, 2x2x2 mm3 for thermal -cold neutrons • PEARL NRC detector, single pixel, 7X7X25 mm3 • Issues • Pixels must be deep for efficiency. Alignment? • Require large beam with low angular divergence and short S-D distance (similar to radiography). Currently about 10 mrad. A 2D NRT detector with 1-2mm pixel resolution should be feasible G.Gorini

  40. Conclusions:in 3 years.Meanwhile... G.Gorini

  41. G.Gorini

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