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The OPERA long baseline neutrino experiment: status and first results

The OPERA long baseline neutrino experiment: status and first results. Luigi Salvatore Esposito Laboratori Nazionali del Gran Sasso on behalf of the OPERA collaboration. Summary. Aim and strategy of the experiment OPERA detector CNGS 2007 run

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The OPERA long baseline neutrino experiment: status and first results

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  1. The OPERA long baseline neutrino experiment: status and first results Luigi Salvatore Esposito Laboratori Nazionali del Gran Sasso on behalf of the OPERA collaboration

  2. Summary • Aim and strategy of the experiment • OPERA detector • CNGS 2007 run • Neutrino interactions in a lead-emulsion target • CNGS 2008 run • Conclusions QUARKS-2008, Sergiev Posad L.S.Esposito

  3. The OPERA collaboration Brussels Bern Neuchatel Zurich Annecy, Lyon, Strasbourg Dubna, Moscow (INR,LPI,ITEP,SINP MSU) Obninsk Zagreb Hamburg, Münster, Rostock Sofia Aichi, Toho Kobe, Nagoya Utsunomiya L’Aquila, Bari, Bologna, Frascati, LNGS, Napoli, Padova, Roma, Salerno Technion Haifa Gyeongsang 36 INSTITUTIONS, ~200 PHYSICISTS METU Ankara QUARKS-2008, Sergiev Posad L.S.Esposito

  4. Physics motivations OPERA is designed for the direct observation of nt appearance in a pure νμ beam in order to provide a final confirmation of neutrino oscillations in the atmospheric sector best fit: M.C. Gonzalez-Garcia et M.Maltoni arXiv:0704.1800 [hep-ph] QUARKS-2008, Sergiev Posad L.S.Esposito

  5. The Cern Neutrino to Gran Sasso (CNGS) program CERN CERN  beam optimized to study the  appearance by  detection 730 Km LNGS Beam mean features: L=730 km ; <E>=17 GeV m/ = 2.1% (e+ e)/ = 0.68%  prompt negligible QUARKS-2008, Sergiev Posad L.S.Esposito

  6. - nm m- nt nm h- nt n(po) e- nt ne p+ p- p- nt n(po) B. R. ~ 17% n B. R. ~ 50% B. R. ~ 18% t decay modes n B. R. ~ 14% Decay “kink” - nm oscillation t- nt ~1 mm Detection of the nt appearance signal The challenge is to identifyntinteractions fromninteractions • Long-baseline, flavour oscillation: small fraction of ν: Far-away source, low flux, weak interaction: • →large targetmassrequired (as usual for ’s …) • CC interactions of ν tagged by the decay(c = 87 μm) : • → need high spatial resolution& lepton Id OPERA solution is a hybrid technique:tracking apparatus with “many” Emulsion Cloud Chamber target units (lead/emulsion structure) QUARKS-2008, Sergiev Posad L.S.Esposito

  7. 1 mm 10 X0 8.3 Kg t n Pb Emulsion layers 10.2cm 12.5cm Electron track The OPERA target • The brick is the target basic component: • 57 nuclear emulsion films interleaved by 1 mm thick lead plates • “Changeable Sheets doublet” made of two double refreshed emulsion films,vacuum packed and glued onto the bottom of each brick to connect TT- brick Emulsion analysis: Vertex, decay kink,e/gID, multiple scattering, kinematics measurements on event-by-event basis!… limited by statistics 2 emulsion layers (44 m thick) poured on a 205 m plastic base 130 000 m² Emulsion: Measuring a vector in space (δx=1 μm δθ=1 mrad) The OPERA target is composed of 155000 bricks QUARKS-2008, Sergiev Posad L.S.Esposito

  8. p.h. 0 max OPERA: a hybrid detector • What the brick cannot do: • trigger for a neutrino interaction • muon identification and momentum/charge measurement  need a hybrid detector On-line analysis of electronic data Spectrometer Target Tracker + Brick Walls Brick finding algorithm   Selected brick is removed from the target and exposed to cosmic rays (alignment). Emulsions are developed and sent to scanning stations / labs QUARKS-2008, Sergiev Posad L.S.Esposito

  9. SM2 SM1 Target tracker Veto Spectrometer: XPC, HPT, RPC, magnet BMS • Modular, Hybrid Detector: • Two supermodules, each containing • a Target Section • - 31 Target Walls to host target units (ECC bricks) • - 31 Target Tracker modules (scintillator strips) • a Magnetic Spectrometer (XPC, RPC, Drift tubes) • Upstream: VETO (glass RPC) • Both sides:Brick Manipulation System (BMS) • Nearby: Brick Assembly Machine (BAM) - Hall B • Data Taking: (1) DAQ nodes + time stamp [Gran Sasso] • (2) Emulsion scanning [Europe and Japan] • … &several facilities for brick & emulsion film handling • (X-ray systems, “Changeable sheets” refreshing and assembly, cosmic-ray exposure, film development) The OPERA detector 8 m 10 m 19m CNGS beam Hall C -Gran Sasso Underground Lab (Italy) QUARKS-2008, Sergiev Posad L.S.Esposito

  10. Brick Assembly Machine: piling/pressing section Brick Assembly Machine: wrapping section Status of brick production • 9*106 emulsions & lead plates • 155 000 bricks to be produced • production rate ~ 700/day • Filling under completion, • ~ 88% now June 10th July 28th QUARKS-2008, Sergiev Posad L.S.Esposito

  11. Automated emulsion scanning Off-line Data Taking ~ 30 bricks will be daily extracted from target and analyzed using high-speed automatic systems Several labs distributed in Europe and Japan S-UTS (Japan) European Scanning System High speed CCD Camera (3 kHz) Piezo-controlled objective lens Synchronization of objective lens and stage scanning speed ~ 20 cm2 / h Constant speed stage Customized commercial optics and mechanics + asynchronous DAQ software Hard-coded algorithms QUARKS-2008, Sergiev Posad L.S.Esposito

  12. nm CC interaction CS doublet h ECC brick 2 mm muon 2 cm Automated emulsion analysis Emulsion scanning is performed in a fully automatic way. About 40 microscopes are operational in the various OPERA scanning laboratories (Europe and Japan). • Predictions from electronic detectors are searched in the Changeable Sheet doublet. • If an interaction is detected in the CS, the brick is exposed to cosmic rays (alignment) and the emulsions are developed and sent to scanning stations/labs • The tracks measured in CSd are followed back inside the brick until tracks stop. • A full scanning around neutrino interaction vertex is performed • Finally the event topology and kinematics reconstructed is performed QUARKS-2008, Sergiev Posad L.S.Esposito

  13. Field of view 16 tomographic images 40m emulsion sheet 2D Image processing 3D reconstruction of particle tracks Passing-through tracks rejection 200 mm Vertex reconstruction Track segments found in 8 consecutive plates Emulsion scanning 0.2 mm Momentum measurement by Multiple Scattering dE/dx for /µ separation at low energy Electron identification and energy measurement QUARKS-2008, Sergiev Posad L.S.Esposito

  14. Status of the experiment May 2003: start of detector construction May 2006: completion of electronic detectors commissioning Aug 2006: technical run, 0.76*1018 pot collected 319 interactions in the rock, mechanical structure and iron of the spectrometer Oct 2006: start of brick production Oct 2007: short physics run (~40% target) 0.824*1018 pot collected 38 events collected in the target May 2008: 135000 bricks inserted (~88% target) Jun 2008:OPERA target will be completed. Start of full data taking, expected about 2.1*1019 pot in130 days of SPS running. QUARKS-2008, Sergiev Posad L.S.Esposito

  15. 2007 run: Interactions outside the Target 331 events passed the analysis cut 303 had been expected: ratio similar to the one observed in 2006 Muon vertical angle Energy of the muon (RPC) QUARKS-2008, Sergiev Posad L.S.Esposito

  16. 2007 run: Interactions inside the Target • 31.5 ± 6expected events in bricks • 38events registered in the target (bricks + scintillators + walls  extra 10% contribution) during the 2007 CNGS run: • 29 CC-like • 9 NC-like Brick handling, Film Processing, Scanning : first test on real neutrino interactions Event analysis is almost completed on this small sample Unfortunately statistics has been quite limited. Wall Finding: > 95% Brick Finding: 80%  7% Position accuracy: 2-3 cm QUARKS-2008, Sergiev Posad L.S.Esposito

  17. CS to brick connection: design accuracy  = 5 mrad  = 22 µm QUARKS-2008, Sergiev Posad L.S.Esposito

  18. CS to brick connection: neutrino interactions  = 54 µm  = 9 mrad Systematical uncertainties (gap, marks, …) dominate QUARKS-2008, Sergiev Posad L.S.Esposito

  19. Scan-back accuracy  = 2 mrad  = 4 µm QUARKS-2008, Sergiev Posad L.S.Esposito

  20. 19 m 8 m 43 mm 17 mm Example of nmCC interaction 5 prongs associated to the neutrino interaction <IP> = 9 mm Electromagnetic shower pointing to the vertex (g conversion) QUARKS-2008, Sergiev Posad L.S.Esposito

  21. PRELIMINARY Kink Charm candidate Secondary Vertex Daughter momentum = 3.9 +1.7-0.9 q kink = 0.204 rad Flight length = 3247 μm Pt = 796 MeV PtMIN = 606 MeV (90% C.L.) QUARKS-2008, Sergiev Posad L.S.Esposito

  22. OPERA τ search sensitivity • 5 years CNGS data taking • ( 4.5 1019 pot/year ) • 1.35 ktons target mass QUARKS-2008, Sergiev Posad L.S.Esposito

  23. Discovery probability % 3 σ sensitivity 4 σ sensitivity SK 90% CL (L/E analysis) Last MINOS measurement OPERA nt observation probability QUARKS-2008, Sergiev Posad L.S.Esposito

  24. The 2008 OPERA run Start: ~ June 20th End: Nov 10th 130 days for the CNGS (200) 2.1*1019 p.o.t (4.5*1019) QUARKS-2008, Sergiev Posad L.S.Esposito

  25. Conclusions The OPERA experiment is running • Electronic detectors fully commissioned • Target filling in progress (completed by June) • Scanning labs are ready (~40 microscopes available) • The OPERA 2007 run allowed to test the full operation chain: • - Test electronic detectors and data acquisition • Test the brick finding algorithm • Test brick handling • Test CS doublet scanning • - Test the target tracker to brick matching and scanning strategy The concept of the OPERA detector has been experimentally validated by measuring neutrino events in the detector. In June the first high luminosity OPERA run will start. With some luck we will measure the first nt candidate event by the end of this year! QUARKS-2008, Sergiev Posad L.S.Esposito

  26. BACKUP SLIDES QUARKS-2008, Sergiev Posad L.S.Esposito

  27. GPS Tflight = 2.44 msec TOPERA = Event TimeStamp TCERN = Time Stamp SPS extraction TOPERA - (TCERN + Tflight) < ∆TGate Time Selection of Beam Events GPS Time Stamp resolution ~ 100 ns QUARKS-2008, Sergiev Posad L.S.Esposito

  28. 10.5 ms 10.5 ms 50 ms The 2006 commissioning run: CNGS and cosmics August 2006 Integrated: 7.6x1017 p.o.t. 319 “beam-related” events [New J. Phys. 8 (2006) 303] QUARKS-2008, Sergiev Posad L.S.Esposito

  29. Primary lepton not identified ,e- ,e Coulombian large angle scattering of muons in Lead : Bck. to t m Charm production in CC, common to the 3 channels Good muon identification is fundamental + e+ h+ D+ Same decay topology as  Hadronic interactions in Pb: Bck. to t h or to t m (if hadron mis-identified as muon)   Expected number of background events after 5 years running with nominal beam: h h -  τsearch: backgrounds QUARKS-2008, Sergiev Posad L.S.Esposito

  30. 6.4o 7.1o m232 = 2.5 x 10-3 eV2 23 = 45° (pt)miss 2.5x10-3 eV2 90% C.L. limits on sin2(213) and 13 : sin2(213)<0.05 13 < 7.1º GeV   eoscillation search nominal CNGS beam 5 years Combined fit of Ee, Evis, (pt)miss to improve S/B ratio QUARKS-2008, Sergiev Posad L.S.Esposito

  31. electronic equipment Designated “radiation safe” areas for electronics electronic equipment CNGS control electronics failure The failed ventilation electronics were installed along the TSG4 (service gallery), next to the ventilation ducts, and in the TCV4 (ventilation chamber). In both areas the radiation levels, as predicted by the FLUKA simulations and confirmed by the radiation protection measurements, are far too high for COTS components the electronics should have failed and they did!! QUARKS-2008, Sergiev Posad L.S.Esposito

  32. Actions for 2008 shutdown During the 2007/2008 shutdown, work is organized to remedy the problem and assure nominal running of the facility for 2008 and beyond. • General guideline: • Replace damaged electronics • Move the electronics out of the CNGS tunnels as possible • For the equipment which must stay in the area: • Create a “radiation-safe” area by adding adequate shielding and move all the electronics into this area • Address the sensitivity to radiation of the installed electronics and investigate upgrade possibilities • Install a radiation monitoring system for electronics as in LHC • Radiation damages repair and protection: • the work is fully funded • electronics repair and reshuffling has started, shielding plugs defined, civil engineering starting • completion of the work expected by the end of week 23 (June 6th) • stable beam during week 25 (~June 20th) QUARKS-2008, Sergiev Posad L.S.Esposito

  33. Summary Event Location & Data analysis QUARKS-2008, Sergiev Posad L.S.Esposito

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