The CNGS project and OPERA experiment at LNGS

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The CNGS project and OPERA experiment at LNGS

The CNGS projectandOPERA experiment at LNGSChiara Sirignano (Salerno University)for the OPERA CollaborationNeutrino 2006 Santa Fe, June 13-19 2006


Outline• Introduction• CNGS beam• OPERA detector status• Emulsion analysis• Oscillation search expected results• Conclusions


Oscillation Projectwith Emulsion tRacking ApparatusInternational Collaboration (Europe + Japan)IIHE (ULB-VUB), BrusselsSofiaIHEP Beijing, ShandongIRB ZagrebLAPP Annecy, IPNL Lyon, LAL Orsay,IRES StrasbourgBerlin Humboldt, Hagen, Hamburg, Münster, RostockTechnion HaifaBari, Bologna, LNF Frascati, L’Aquila, LNGS, Napoli,Padova, Roma La Sapienza, SalernoAichi, Kobe, Nagoya, Toho, UtsunomiyaINR Moscow, ITEP Moscow, JINR Dubna, ObninskBern, Neuchâtel, ZurichMETU Ankara• Long baseline experimentCNGS pure ν μbeam, = 732 km, = 17 GeV• Appearance signal ν μ→ ν τ(by product ν μ→ ν e)• Hybrid setup (Nuclear Emulsions + electronics)• Atmospheric neutrino data allowed region oscillation search


ν τappearance signature• Detection of ν τ CC interaction and direct observationof decay topologies• High background rejectionν ττdecaykinkτ~ 0.6 mmτ − μ − ν τ ν μ (17.4%)τ − e - ν τ ν e (17.8%)τ − h - ν τ n(π ο ) (49.5%)τ − π + π − π − ν τ n(π ο ) (14.5%)Nuclear emulsions (ECC)• 3D particle reconstruction• Sub-micron spatial resolution


CNGS beamThe beam was optimized tomaximize ν τCC interaction rateat LNGS.732 KmWe will have 4.5x10 19p.o.t./year, 200days/year17 GeV(ν e+ ν e) / ν μ0.87%ν μ/ ν μ2.1%ν τpromptnegligibleν μCC + NC int/yearν τ CCint/year~ 6200~25(Δm 2 = 2.4x10 -3 eV 2 ,maximal mixing)


700 m 100 m 1000m 67 mvacuumHornDecay tubevacuum tests successfulCivil engineering completed (June ’03)Hadron stopper and decay tube installed (June ’04)Target section completed (commissioning July ‘06)Hadron stop


OPERA detector at LNGSTarget mass: 1766 tons, 206336 ECC bricks(24 M of Pb + emulsion plates)rock thickness 1400m (3800SM1m.w.e.)cosmic muon flux: ∼1/m 2 /hSM2υHall BHall CICARUSBOREXINOTargets(31TT+31Walls/SM)OPERA (CNGS1)Magnetic Spectrometers(Magnet + RPC + XPC + HPT)


OPERA bricks1 ECC= 56 Pb + 57 emulsions•ECC : target basic component• Em Provides high space resolution+ Lead active target mass•Compact and modular structure1 mmDedicated robotswill pile 10 X0’s up andhandle 1000 ECC/day8.3 KgνPbτBrick Emulsion Assembly layersMachine10.2cmNeutrino interaction location and study12.5cm2 emulsion layers(44 μm thick)poured on a200 μm plastic base12 M emulsion films12 M thin lead foilsbyFuji Film (Japan)JLGoslar (Germany)- Measurement of hadrons momenta by MCS- dE/dx pion/muon separation at low energy- Electron identification and energy measurements for electrons andphotons


Active target (brick walls + electronic trackers)Suspensionfrom the topwall31 X 2 walls52 x 64 bricks/wallTensioningfrom thebottom- Bricks are arranged in walls- Refined and light structure- Accurate alignment achievedTime correlation and interactionBrick selection is provided byelectronic detectors31 tracking planes (TT)/super modulesυp.h.0 max


Target tracker● Trigger: ε > 99%● Brick finding : ε ≈ 70÷80%● Initiate muon taggingPlastic scintillator strips(AMCRYS-H, 6.7m x 2.6cm x 1cm)readout by Kuraray WLS fibres +Hamamatsu PMT’s (64 channels)Reconstructed cosmic track1.7 m64 strips/module2 x 256 strips6.9mTracker wallLNGS


Muon spectrometerM ~ 950tcoil12 Fe slabs(5cm thick)8.2m2 cm gapsRPC’sDrift tubesB= 1.55 TbaseslabsInner Tracker: 11 planes of RPC’s22 bakelite RPC’s (2.9x1.1m 2 ) / planePrecision tracker: 6 planes ofdrift tubesμ identification: ε > 95% (TT)Δp/p < 20% , p < 50 GeV/cmisidentified μ charge prob. ≈ 0.1 ÷ 0.3%diameter 38mm, length 8m4 staggered layers / plane,each layer consisting of 168 tubesefficiency: ∼99%space resolution: ∼300µm


OPERA run…νPb/Em.bersaglioμLoading stationTarget Trackers+ ECCVacuum sucker Vehicle (VV)Selected bricksextracted by the BMSFast emulsion scanning required (20 cm 2 /h/side)30 bricks/day extracted


Detector construction statusXPC A 1&2Mar ‘05HPT A 1- 6Mar’05-May’06Magnet 1&2May’03-Apr’05ElectronicsJul’05-Jun’06Mechanical structureMay’04-Jul’05BMS rs & csDec’05-Mar’06VetoJun 06SM1 TargetDec’05-Nov’05SM2 TargetJan-May ’06XPC B 1&2CompletedHPT B 1-6Jun-Dec06


Detector commissioningElectronics commissioning is now ongoing in order to beready during CNGS low intensity runTT reconstructionRPC efficiency


Automatic emulsion scanningEuropean Scanning SystemS-UTS(Japan)High speedCCD Camera (3 kHz)Piezo-controlledobjective lensConstant speed stageSynchronization ofobjective lens and stageCustomized commercialoptics and mechanicsDedicated hardwareAsynchronous DAQ softwareScanning speed ~ 20 cm 2 /h/sideSingle side track finding efficiency ~ 95%Sheet-to-sheet alignment (8 GeV/c) ~ 0.5 μmAngular resolution ~ 2 mradScanning speed in point scan mode 1.2 s/prediction(⇒ 15 min/brick for 15 predictions, 1h35min/brick for 100 predictions)


On-lineField of view16 tomographic images3D reconstruction of particle tracks2D ImageprocessingOff-linePlate to platealignment&Vertexreconstructionσ=0.43 μm734 entries


Interaction studyScan-back strategy tested on 8 GeV/c pions to produce interactions• Scanback: measure tracks on downstreamplate and follow back to interactionpoint• Area Scan around track disappearancepoints to confirm the interactionTrackG 1TrackM980μmTrackD 2TrackD 1TrackG 2TrackM50 μmTrackD 3TrackD 2TrackD 1More than 200 pioninteractions fullyreconstructed


PEANUT:rehearsal exposure to NUMIDesigned to observe ν interactions in OPERA-like bricksHybrid apparatus (ECC+SFT)in front of MINOS near detectorat Fermi LabExpected ~ 5 evts/day/brickWide area scanning and predictionscanning were successfulboth in Europe and JapanMINOSSB dataSFT tagged vertexExample of a neutrinointeraction fullyreconstructed


ν μ →ν τ oscillation searchτ decaychannelSignalΔm 2 = 3.0 x 10 -3 eV 2Backgroundτ → µΔm 2 = 2.4 x 10 -3 eV 2 19.9 1.03.65.60.23τ → e4.36.70.23τ → h3.85.90.32τ → 3h1.11.70.22ALL12.8Main background sources:full mixing, 5 years run @ 4.5x10 19pot / year-charm production and decays- hadron re-interactions in lead- large-angle muon scattering in lead


OPERA potential4σ discovery probability Exclusion plot at 90% c.l.


ν μ → ν e oscillation searchΔm 232 = 2.5 x 10 -3 eV 2 Θ23 = 45°nominal CNGS beam5 yearsCombined fit of E e , E vis , (pt) miss2.5x10 -3 eV 2 090% C.L. limits on sin 2 (2Θ 13 ) and Θ 13 :sin 2 (2Θ 13 )


Conclusions• The OPERA experiment was designed to unambiguouslyconfirm ν μ → ν τ oscillations at atmospheric Δm 2 scale• The detector construction and installation at LNGS isalmost completed and the electronics is under commissioning• Emulsion scanning can locate and fully reconstructpion and neutrino interactions both in Europe and in Japan• CNGS beam (low intensity) will be delivered to LNGS fromAugust 18 and the DAQ is ready.


Event rate in 2006Bricks in the targetNeutrino interactionsin the target3/7/20063/7/2006DaysDaysInteractions/day31/8/2006In this scenario, the high intensitybeam will be delivered in midOctober and 100 neutrinointeractions will be collectedDays

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