1. The OPERA Experiment 12 th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD10) 7-10 June 2010, Siena, Italy Jonas Knüsel Albert Einstein Center for Fundamental Physics Laboratory for High Energy Physics University of Berne On behalf of the OPERA collaboration 1 jonas.knuesel@lhep.unibe.ch

2. The Photographic Emulsion Technology of the OPERA Experiment on its Way to Find the  →  Oscillation OPERA Oscillation Project with Emulsion tRacking Apparatus 2 jonas.knuesel@lhep.unibe.ch

3. JINST 4 (2009) P06020 New Journal of Physics (2006) 303a JINST 4 (2009) P06020 Introduction The OPERA experiment The nuclear emulsion technology On the way to find the  →  oscillation Conclusion 3 jonas.knuesel@lhep.unibe.ch

4. Introduction The OPERA collaboration LAPP Annecy IPNL Lyon IPHC Strasbourg INR, LPI, ITEP, SINP Moscow JINR Dubna IRB Zagreb Bari Bologna L’Aquila LNF Frascati LNGS Napoli Padova Roma Salerno Bern ETH Zurich ULB Brussels Hamburg Münster Rostock Aichi Toho Kobe Nagoya Utsunomiya Technion Haifa METU Ankara Jinju 33 Institutions ~200 physicist 4

5. Introduction Physics motivation Neutrinos as fundamental particles of the SM Flavour vs. Mass Eigenstates: – Mixing – Oscillation! Oscillation parameters: θ and ∆m 2, available in experiment: L, E Detection of Tau Neutrino from an oscillated muon neutrino via the tau decay kink. – High target mass to compensate low neutrino cross section: use LEAD – High granularity and resolution to see the tau kink: use PHOTGRAPHIC EMULSIONS Prove neutrino oscillation by observing the Tau appearance. 5 jonas.knuesel@lhep.unibe.ch

6. Introduction Principle of topological  detection Topology Selection   μ, e, h, 3h h h cτ = 87 micron Tau decay kink Also other topologies, according to decay: 6 jonas.knuesel@lhep.unibe.ch  

7. 17 GeV L730 km ( e + e )/  CC 0.87%  /  CC 2.1%  prompt negligible The OPERA experiment From CERN to Gran Sasso CERN LNGS 730 km 7 jonas.knuesel@lhep.unibe.ch Expected number of interactions in 5 years running: ~23600  CC + NC ~205 e + e CC ~115  CC (  m 2 =2.5 x 10 -3 eV 2 ) ~ 10 tau decays are expected to be observed, with less than 1 background event

8. The OPERA experiment The OPERA detector Dimension of the detector: 20m x 10m x 10m 8

9. The OPERA experiment The OPERA detector Brick Wall and Brick Manipulation system. bricks scintillator 9 jonas.knuesel@lhep.unibe.ch

10. The OPERA experiment The OPERA basic unit: the „brick“ 125mm 100mm 75.4mm 8.3kg 10X 0 Neutrino Beam OPERA emulsion film Lead plate : 1mm The Emulsion Cloud Chamber (ECC) The OPERA emulsion film plays the main role in this experiment. These emulsion films are scanned by automatic optical microscopes. > 200000 m 2 of emulsion surface in OPERA 57 emulsion per brick CSd 10 jonas.knuesel@lhep.unibe.ch

11. The OPERA experiment The scanning systems Scanning speed/system: 75cm 2 /h High speed CCD camera (3 kHz), Piezo- controlled objective lens FPGA Hard-coded algorithms Japan overall capacity: ~ 200 cm 2 /h Scanning speed/system: 20cm 2 /h Customized commercial optics and mechanics Asynchronous DAQ software EU overall capacity: ~ 200 cm 2 /h 11 jonas.knuesel@lhep.unibe.ch JapanEurope ESS: (European Scanning System)SUTS (Super Ultra Track Selector)

12. The OPERA experiment The scanning procedure  12 57 565554 53 5251504948 … 2 1 CSd Scanback Track follow-up film by film: Alignment using cosmic ray tracks Definition of the stopping point Volume-Scan Volume scanning (2-3 cm 2 ) around the stopping point 12 jonas.knuesel@lhep.unibe.ch

13. The OPERA experiment The scanning analysis JINST 4 (2009) P04018 Different steps of the emulsion data processing All base-tracks in the 11 films Long tracks for the alignment Tracks belonging to the vertex ≈ 2  m Position residuals for the position alignment 13 jonas.knuesel@lhep.unibe.ch

14. The OPERA experiment From the m to the  m scale Detector Muon Spectrometer O (m) 14 jonas.knuesel@lhep.unibe.ch

15. The OPERA experiment From the m to the  m scale Target Tracker O (m)  O (cm) 15 jonas.knuesel@lhep.unibe.ch

16. The OPERA experiment From the m to the  m scale The ECC brick O (m)  O (cm) extraction 16 jonas.knuesel@lhep.unibe.ch

17. The OPERA experiment From the m to the  m scale The Changeable Sheet (CS) O (m)  O (cm)  O (mm) JINST 3 (2008) P07005 CS: 2 emulsion film located on the brick 17 jonas.knuesel@lhep.unibe.ch

18. The OPERA experiment From the m to the  m scale O (m)  O (cm)  O (mm) emulsion film doublets CS confirmes prediction by electronic detectors. Move from cm-range (electronic detector) to mm-range Bricks are only developed after CS confirmes prediction 18 jonas.knuesel@lhep.unibe.ch

19. The OPERA experiment From the m to the  m scale O (m)  O (cm)  O (mm)  O (  m) The emulsion This is the main part of the OPERA experiment. The essentiall stuff happens here. Vertex finding and topology classification. 1 cm 19 jonas.knuesel@lhep.unibe.ch

20. The nuclear emulsion technology Renaissance The central part of OPERA happens in emulsion films: AgBr Crystal, size ~ 0.2 microns Semiconductor detector technique, band gap ~ 2.6eV Signal amplified by developing the photographic films. After developing the „silver grains“ are read out by optical microscopes Plastic Base (205micron) Emulsion Layer Emulsion Layer (44micron) 20 jonas.knuesel@lhep.unibe.ch

21. The nuclear emulsion technology Sub micron resolution 3D tracking 50 micron Microscopic Image Recorded as silver grains along the line particle passed through Resolution of 0.3 micron 21 jonas.knuesel@lhep.unibe.ch cτ of tau: ~87 microns

22. The nuclear emulsion technology Microscope images JINST 4 (2009) 6020 Nuclear emulsion image as seen by the microscope Peculiar event: neutrino interaction occured inside the emulsion layer 22 jonas.knuesel@lhep.unibe.ch

23. On the way to find the  →  oscillation First OPERA run 2006 Only electronic detectors, at that time: No bricks in target, then. Cosmic muon induced background Muons from CNGS beam. Angle w.r.t. earth curvature: 3.4 degree. New Journal of Physics 8 (2006) 303 23 jonas.knuesel@lhep.unibe.ch ✔ Neutrino beam ✔ Electronic detector

24. On the way to find the  →  oscillation  CC interaction muon primary vertex 4 tracks with IP < 2  m secondary vertex 2 tracks with IP < 4  m 2.2 cm 7 mm 24

25. y On the way to find the  →  oscillation  CC interaction muon primary vertex 4 tracks with IP < 2  m 6 Gammas reconstructed 4 Gammas from 1ry vtx 2 Gammas from 2ry vtx secondary vertex 2 tracks with IP < 4  m 2.2 cm 7 mm 25

26. On the way to find the  →  oscillation Charm candidates Theta kink : 0.204 rad P daughter : 3.9 (+1.7 -0.9) GeV P T : 800 MeV Flight length: 3247.2 μm 2 EM-showers point to vertex Charm topology analogous to tau (similar lifetime): reference sample for the decay finding efficiency 26 jonas.knuesel@lhep.unibe.ch

27. On the way to find the  →  oscillation Charm candidates Event in Europe (D0 4 prong)Event in Japan (kink) TopologyKinkVeeTrident4Vee Observed events5+2N151+N31 27 jonas.knuesel@lhep.unibe.ch

28. On the way to find the  →  oscillation e interaction 6 e interactions found in a subsample of 690 CC located interaction (expected are about 6) 28 jonas.knuesel@lhep.unibe.ch

29. On the way to find the  →  oscillation search for  Search for  is ongoing Systematic decay studies are performed for all interactions About 2  are expected from 2008-2009 run 29 jonas.knuesel@lhep.unibe.ch ChannelSignalBackground  →   → e3.50.17  → h3.10.24  → 3h0.90.17 Total10.40.75

30. On the way to find the  →  oscillation work in progress... CNGS run 2010 is going well (started on April 20th 2010) Continuous extraction of bricks from triggered events About 100 bricks / week are extracted, developed and sent to the labs Systematic decay search studies are performed to find all possible decay topologies. 30 jonas.knuesel@lhep.unibe.ch

31. Conclusion OPERA, the largest nuclear emulsion experiment is successfully taking data. OPERA has collected for 5.3E19 pot in 2008 and 2009. The full chain of events handling/analysis is proven. Electronic detector performance is reliable and well understood. Several charm events are found as expected. The first  event is close... 31 jonas.knuesel@lhep.unibe.ch

32. 32 jonas.knuesel@lhep.unibe.ch

33. Additional Information 2008 run status (May 5th, 2010) 0mu1muAll Events predicted by the electronic detector40612921698 Found in CS27610561332 Neutrino interactions in the bricks155798953 Located in dead material84048 Interaction in the upstream brick63541 Decay search completed130673803 Decay search completed for 84.3% of the sample 22 observed charm candidates 33 jonas.knuesel@lhep.unibe.ch

34. Decay search completed for 42.1% of the located event sample 4 observed charm candidates 0mu1muAll Events predicted by the electronic detector109724603557 Events with at least 1 brick extracted105023893439 CS scanned82621432969 Found in CS44714181865 Neutrino interactions in the bricks112550662 Located in dead material31518 Interactions in the upstream brick45054 Decay search completed53226279 Additional Information 2009 run status (May 5th, 2010) 34 jonas.knuesel@lhep.unibe.ch

35. Additional Information Decay search – detect kink topology 35 jonas.knuesel@lhep.unibe.ch