1. OPERA Experiment, Brick Finding Program A. Chukanov Joint Institute for Nuclear Research ISU, 12 th February, 2007

2. Outline OPERA experiment Status of the OPERA detector Brick Finding program description Conclusion

3. OPERA: Oscillation Project with Emulsion tRacking Apparatus 732 km Long baseline experiment Direct search for    oscillations by looking at the appearance of  in a pure  beam to explain atmospheric neutrinos anomaly and results of K2K and MINOS. Search for the sub-dominant   e oscillations for  13 measurement OPERA Detector

4. Detection of the  appearance signal Two conflicting requirements:  Large mass  low Xsection  High granularity  signal selection  background rejection Target:1800 tons, 5 years running 30 000 neutrino interactions ~150  interactions ~15  identified < 1 event of background Toplogy selection:  Kink signature The challenge is to identify  interactions from  interactions   -- Decay “kink”  -- ~1 mm  oscillation --

6.  Target (31 TT modules + 31 Brick walls / SM) Magnetic Spectrometers SM1SM2 Modular structure: 2 super-modules Total target mass: 1.8 kt The OPERA detector

7. Target Tracker 7 m 6.9m 1.7m Plastic scintillator strips (AMCRYS-H, 6.7m x 2.6cm x 1cm) readout by Kuraray WLS fibres + Hamamatsu PMT’s (64 channels) Target Tracker tasks Target Tracker tasks ● Trigger:  > 99% ● Brick finding :   70  80% ● Initiate muon tagging 31 walls

9. Muon spectrometer  identification:  > 95% (TT)  p/p < 20%, p < 50 GeV/c misidentified  charge prob. < 0.3% B= 1.55 T base slabs coil 8.2 m M ~ 950t Drift tubes 12 Fe slabs (5cm thick) RPC’s ● muon identification (TT) ● range measurement 11 + 11 planes of RPC’s 21 bakelite RPC’s (2.9x1.1m 2 ) / plane Inner Tracker Precision Tracker 6 planes of drift tubes space resolution:  300µm ● momentum measurement

11. Lead – Emulsion target 8.3kg brick (target unit) 56 Pb plates + 57 emulsions 2 emulsion layers (44  m thick) poured on a 200  m plastic base 12.5cm 10.2cm 10 X0’s ● Micro-metric space resolution (Emulsion) + target mass (Lead) ● Compact and modular structure Total target mass : 1766 t (206336 bricks, 12 M emulsions and Pb plates)

12. Brick Manipulator System Ventouse Vehicle Brick Carousel mechanism Robot for brick insertion (target filling) and removal (during run)

13. Automatic scanning of nuclear emulsions High speed CCD Camera (3 kHz) Piezo-controlled objective lens Constant speed stage Synchronization of objective lens and stage ~ 30 bricks will be daily extracted from target and analyzed using high-speed automatic systems S-UTS (Japan) Customized commercial optics and mechanics + asynchronous DAQ software Hard-coded algorithms scanning speed ~ 20 cm 2 / h European Scanning System

14. Two testing runs August 2006 testing CNGS beam testing Changeable Sheet October 2006 register events in real bricks water leak in a reflector cooling system 

15. There are 28 beam correlated events have been registered during october run

20. Brick Finder Program

21. Brick Finding Program requirements – high efficiency No new bricks will be inserted (to save the effective mass of target) ~30 Bricks per day (5 years of data taking)

22. Cleaning Event Cellular Automation

23. Reconstruction muon track direction Hough Method Kalman Filter Tracing Method

24. Reconstruction Hadron Jet direction Reweighting hits method

25. Define wall with interaction Neural Network

26. Find Brick Define most probable brick

27. Results (   CC events) “1 of 3” Full detector Wall reconstruction efficiency: 1 wall 0.940.85 Brick finding efficiency 1 brick0.710.70 2 bricks0.870.85 3 bricks0.910.92