Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 1/21 Nuclear Emulsion Scanning in OPERA: Methods and Results The ECC technique in OPERA The European Scanning System The Japanese Scanning System Data quality and analysis capabilities

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 2/21 The ECC technique in OPERA Emulsion Cloud Chamber: a stack of dense material (e.g. lead) interleaved with thin tracking planes of nuclear emulsions Ionizing particles sensitize atoms Upon development, metallic Ag grows in grains 0.5÷1 μm AgBr in gel matrix – continuous sensitivity since production Opera ECC cell: 1 lead plate (1 mm) 1 emulsion plate (291μm) in contact Emulsion layers (43 μm) Transparent plastic support (205 μm)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 3/21 The ECC technique in OPERA Opera: ECC bricks in a beam (CNGS), searching for appearance due to neutrino flavour oscillation Average residuals of grains from microtrack fit: μm Topological analysis of interactions is possible to search for nonambiguous appearance signature CNGS microtrack = sequence of aligned grains in a single emulsion layer

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 4/21 The ECC technique in OPERA Evolution of automatic scanning systems OPERA (CERN-LNGS) TS (Track Selector) Nagoya NTS (New Track Selector) Nagoya UTS (Ultra Track Selector) Nagoya S-UTS (Super UTS) Nagoya SySal (System of Salerno) Salerno ESS (European Scanning System) European labs CERN- NIKHEF system Speed: 1 cm 2 /h/side Speed: cm 2 /h/side CHORUS (WA95-CERN)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 5/21 The European Scanning System CMOS camera 1280×1024 pixel 256 gray levels 376 frames/sec (Mikrotron MC1310) XY stage (Micos) 0.1 μm nominal precision Emulsion Plate Z stage (Micos) 0.05 μm nominal precision Illumination system, objective (Oil 50× NA 0.85) and optical tube (Nikon)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 6/21 The European Scanning System The ESS is mostly SW-based and very modular New, better components are quickly integrated and performances increase DALSA 1M60 Camera, 3×Genesis Photonfocus camera,Matrox Odyssey Mikrotron cameraSW improvements Hitachi KPF110 camera Scanning speed (area scan of 43 m thick emulsion)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 7/21 280×365μm 2 Tomographic sequences Z axis moving, 2D images spanning emulsion thickness Move XYZ to next view Process/save data Next field of view, Z at top, new cycle The European Scanning System DAQ cycle (185 ms) Camera 2D Images (peak 452 MB/s, avg. 97 MB/s) Vision Processor (Matrox Odyssey) Binarized 2D Images Host PC (Dual Pentium Workstation) Running WinXP 3D microtracks XYZ Motion Commands Motion Controller (National Instruments FlexMotion) Motors (VEXTA Nanostep) Power Functional blocks

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 8/21 The European Scanning System 15 images 10 grains signal/image, 3000 grains background+ noise, shadows, scratches, spots 2D FIR Filter+ Equalization+ Threshold Grain recognition (Host PC, multithreaded Assembler code) 300 ÷ 3000 microtracks / view 3D microtrack reconstruction (Host PC, multithreaded C++ code)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 9/21 The European Scanning System Data sent to temporary file servers Distributed computing based on.NET Batch Manager coordinates jobs and directs Scan Servers Data Processing Servers take care of heavy computing for data postprocessing Data ready for physics analysis are written to Oracle DB servers (also used to share data)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 10/21 A track is the result of the connection of two microtracks on opposite sides of a plate The European Scanning System Performances of the European Scanning System Scanning speed: 20 cm 2 /h/side (40 GB/day/microscope of raw data) Purity: 10 fake tracks / cm 2 (slope < 0.5) Efficiency: up to 95% using tracks, ~100% using microtracks (however, background is larger with microtracks) 0.3÷0.7μm precision for reconstructed tracks

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 11/21 The Japanese Scanning System Custom CMOS camera 512×512 pixel 3000 frames/sec Piezoelectric fine drive for Z motion of lens X axis is driven with continuous motion Oil objective 35× NA 0.85 Mechanics based on Nikon microscope stages X/Y/Z nominal precision = 0.1 m Super-UTS microscope (Japanese scanning system)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 12/21 The Japanese Scanning System The Super-UTS is mostly hardware based, with many custom components High speed achieved mostly by high repetition rate of DAQ cycle Piezoelectric motion for lens allows high accelerations with minimum vibrations X axis is operated in continuous motion on a line; Y axis moves to switch to next line X Y Lens motion is synchronised with X motion of stage to follow the field of view

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 13/21 The Japanese Scanning System The Super-UTS is mostly hardware based, with many custom components Camera 2D Images (3000/s) Super-UTS Image processing, largely based on FPGA Motion control 3D microtracks Host PC 3D microtracks Start/Stop, Control Motors, Piezo drive Power Functional blocks Image processing and motion control are combined in a single piece of HW: synchronisation must be perfect!

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 14/21 The Japanese Scanning System Principle of track recognition in SUTS: pile up and sum pulse height Grains of a microtrack in the optical tomography (after noise filtering) Shift images (many trials using predefined slopes) Sum images and get a peak over a background

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 15/21 The Japanese Scanning System Data flow in the SUTS-based scanning station Data reduction is applied at the level of the local storage server by deleting tracks that cannot be connected across neighbour plates (linklet concept) SUTS Host PCs Local storage server OPERA Central DB (Oracle)

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 16/21 A track is the result of the connection of two microtracks on opposite sides of a plate The Japanese Scanning System Performances of the Super-UTS Scanning speed: 50 cm 2 /h/side average (72 cm 2 /h/side peak) Purity: 10 4 fake tracks / cm 2 (slope < 0.4) Efficiency: 95% using tracks 10 4 base trk/cm 2 /(±0.4) 2 Different Ph sum cut Efficiency vs Number of Fake

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 17/21 Data quality and analysis capabilities Residuals of tracks w.r.t. multi-plate fit of 8 GeV t, l Slope=0.2 t~0.3 m Top view Side view Slope=0.2 l~0.5 m Slope=0.7 t~0.7 m t l plate-to-plate alignment by high-energy passing-through-tracks

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 18/21 Data quality and analysis capabilities Interaction/decay vertex reconstruction interaction vertex from test exposure at NuMi beam (FERMILAB): not a simulation! Distance of extrapolations at vertex point (in lead): 6.2 m Sample of multi-prong interaction vertices from NuMi beam

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 19/21 Data quality and analysis capabilities Momentum measurement through Multiple Coulomb Scattering Particle momentum is related to the fluctuation of track slope due to scattering (mostly in lead) Pb j i ij Em Good agreement between reconstructed and simulated momenta 26% momentum resolution obtained at 8 GeV/c

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 20/21 Data quality and analysis capabilities Particle identification through neural network analysis Input variables : track and film number longitudinal and transversal profile Network output

Cristiano Bozza – The OPERA Collaboration – Oct 2007, Villa Olmo (Como – Italy) 21/21 Conclusions The two automated scanning systems used in OPERA have been presented: the ESS has a SW-oriented approach the SUTS has a HW-oriented approach Unprecedented scanning speed is coupled with precision, efficiency and purity 20÷50 cm 2 /h/side on 43 m emulsion layers 0.3÷0.7 m precision 90%÷95% track finding efficiency 10÷10 4 fake tracks / cm 2 (slope < 0.5) Automatic measurements with micrometric precision allow large scale sample for several analysis modes: Topological event reconstruction (unique feature of nuclear emulsion) Momentum measurement (26% resolution at 8 GeV/c) Particle identification (95% e- separation with 1% contamination above 2 GeV/c)