Presentation on theme: "1XIXNPDC07092005G.Gorini ANCIENT CHARM A new project for neutron-based 3D imaging with applications to cultural heritage research G. Gorini on behalf."— Presentation transcript:
1XIXNPDC G.Gorini 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
2XIXNPDC G.Gorini Outline ANCIENT CHARM State of the art Project objectives and plans
3XIXNPDC G.Gorini ANCIENT CHARM
4XIXNPDC G.Gorini ANCIENT CHARM Analysis by Neutron resonant Capture Imaging and other Emerging Neutron Techniques: new Cultural Heritage and Archaeological Research Methods EU funded ADVENTURE project under the New and Emerging Science and Technology (NEST) programme of FP6. Expected start date: 01/2006. Duration: 36 months
5XIXNPDC G.Gorini 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.
6XIXNPDC G.Gorini The ANCIENT CHARM Collaboration A mix of expertise in neutron instrumentation and archaeology
7XIXNPDC G.Gorini Available neutron sources NIPS, Budapest (reactor) PGAA in regular 10 7 n/cm 2 s 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 10 9 n/cm 2 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.
8XIXNPDC G.Gorini 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 – cm -2 s -1 Initial beam size = 5 cm x 11.5 cm Available in 2007 FRM-II 20 MW reactor First time critical
9XIXNPDC G.Gorini The ISIS Facility
10XIXNPDC G.Gorini 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).
11XIXNPDC G.Gorini (I)NAA PGAA NRCA T 1/2 E Resonances Neutron Energy Cross section E Neutron Capture
12XIXNPDC G.Gorini 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
16XIXNPDC G.Gorini xyz translation rotation table Detection system Table Sample Beam Pb + 6 LiF Lead glass CCD Mirror 420 m-thick ZnS(Ag) / 6 LiF with Al backing 100 m-thick ZnS(Ag) / 6 LiF Conversion screen Field of view : 2.7 mm x 3.4 mm Image size : 640 x 512 Effective pixel size = 54 m Typical exposure time ~ 2 s Binning 2x2 12 bit CCD SensiCam camera Pixel size : m 2 Number of pixels : Readout Time : 8 fps
17XIXNPDC G.Gorini Quality-control of pyrotechnic cutters used in space programs (Ariane) Application in Aerospace Industry Computer assisted inspection
18XIXNPDC G.Gorini 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 beam dimensions 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 Neutron focusing lens
19XIXNPDC G.Gorini Neutron Diffraction
20XIXNPDC G.Gorini GEM
21XIXNPDC G.Gorini ENGIN-X
22XIXNPDC G.Gorini The ENGIN-X transmission detector 100 element transmission detector for residual stress measurements Efficiency 85% at 1 Å Pixel array 10 x 10 Pixel size 2 mm x 2 mm on 2.5 mm pitch Count rate 10 6 per PMT ie or 64 mm 2 GS20 Glass scintillator pixels Fibre light guides Hamamatsu 16 channel position sensitive PMTs
23XIXNPDC G.Gorini Neutron transmission and Bragg edges Pulsed neutron source Incident spectrum Sample (, A) Transmitted spectrum x Pixelated detector
24XIXNPDC G.Gorini Strain around a cold expanded hole
30XIXNPDC G.Gorini NRCA on a prehistoric bronze axe
31XIXNPDC G.Gorini Comparison: NRCA vs. PGAA PGAA c thermal capture cross section branching detection efficiency a atomic abundance NRCA A,r resonance area 1/E r flux shape
32XIXNPDC G.Gorini PGAA NRCA PGAA (at Budapest) and NRCA (GELINA) Accuracy for Cu in a bronze artefact about 1% k o and S r 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
33XIXNPDC G.Gorini Pilot NRCA tests on ISIS Small YAP detector Threshold: 0.6 MeV
34XIXNPDC G.Gorini PROJECT OBJECTIVES AND PLANS
36XIXNPDC G.Gorini 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.
37XIXNPDC G.Gorini 400 mm Boron collimator YAP Crystal detectors Transmission detector XYZ- stage Li (or B) cladding
38XIXNPDC G.Gorini Transmission vs. measurements 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. 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.
39XIXNPDC G.Gorini A 2D NRT detector Experience on existing detectors at ISIS 1.Engin-X 2D transmission monitor: 100 pixels, 2x2x2 mm 3 for thermal - cold neutrons 2.PEARL NRC detector, single pixel, 7X7X25 mm 3 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
40XIXNPDC G.Gorini Conclusions: in 3 years. Meanwhile...