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Status of the OPERA long-baseline neutrino experiment

Magali Besnier. PIC 07- Annecy. Status of the OPERA long-baseline neutrino experiment. June 27 th 2007. OPERA. 37 INSTITUTS, ~ 160 PHYSI CISTS. International Collaboration (Europe + Japan) IIHE (ULB-VUB), Brussels Sofia IHEP Beijing, Shandong IRB Zagreb

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Status of the OPERA long-baseline neutrino experiment

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  1. Magali Besnier PIC 07- Annecy Status of the OPERA long-baseline neutrino experiment June 27th 2007

  2. OPERA 37 INSTITUTS, ~160 PHYSICISTS International Collaboration (Europe + Japan) IIHE (ULB-VUB), Brussels Sofia IHEP Beijing, Shandong IRB Zagreb LAPP Annecy, IPNL Lyon, IRES Strasbourg Berlin Humboldt, Hagen, Hamburg, Münster, Rostock Technion Haifa Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Napoli, Padova, Roma La Sapienza,Salerno Aichi, Kobe, Nagoya, Toho, Utsunomiya INR Moscow, ITEP Moscow, JINR Dubna, Obninsk Bern, Neuchâtel, Zurich METU Ankara Possibility of nmneoscillation search for q13 measurement First direct observation of nmnt oscillation Oscillation ProjectwithEmulsiontRackingApparatus Search for tauneutrino appearance at Gran Sasso laboratory in a pure muonneutrinobeam produced at CERN (732 km)

  3. 700 m 100 m 1000m 67 m vacuum 4.5 1019 p.o.t. /year Hadron stop Decay tube vacuum tests successful Horn CNGS beam (CERN Neutrino to Gran Sasso) To Gran Sasso 400GeV Ø at GS=2km 3.2° angle Civil engineering completed (June ’03) Hadron stopper and decay tube installed (June ’04) Target section completed in 2006 (first CNGS beam in August 2006)

  4. CNGS beam (CERN Neutrino to Gran Sasso) 4.5 1019 p.o.t. /year nmFlux at Gran Sasso (given by Fluka) Number of expected events at Gran Sasso (0-100 GeV): (before reconstruction and detection efficiencies) N nm CC= 3000/yr/kT N neCC= 20 /yr/kT N nt CC= 19 /yr/kT P(nm->nt)*s(nt CC) Dm223= 2.5 10-3 eV² nm flux  appearance signature .Detection of  CC interaction and direct observation of decay topology .High background rejection tdecay kink t • t-m- nt nm (17.4%) • t-e- nt ne (17.8%) • t-h-nt n(po) (49.5%) • t-p+ p- p-nt n(po)(14.5%) ~ 0.6 mm nt

  5. OPERA Performances fornmnt oscillation full mixing, 5 years run @ 4.5x1019 pot / year Number of expected signal and background events Most important background : charm particle production Best value ofDm223= 2.5 10-3 eV² 3s range : 1.9 - 3.2 10-3 eV² T.Schwetz, hep-ph/0606060

  6. m spectrometer: Dipolar magnet + RPC chambers B=1.6 T Hall B n Precision tracker: Drift tubes ICARUS(CNGS2) brick (56 Pb/Em. “cells”) BOREXINO Hall C OPERA (CNGS1) 8 cm (10X0) module Target Trackers Pb/Em. target 2 super modules 1 super module = 31 walls + 31 Target Tracker + 1 muon spectrometer (21 RPC planes + 6 drift tube planes) 52*64 bricks/wall brick wall 206 336 bricks Lead target : 1.8 kTon ~6000 nmCC/yr scintillator strips p/p < 20% for E<50GeV OPERA detector at LNGS (Notional Laboratories of Gran Sasso, Italy, 120 kms from Rome) rock thickness 1400m (3800 m.w.e.) cosmic muon flux: 1/m2/h

  7. OPERA bricks : main target detector component Emulsion Cloud Chamber (ECC) :1 ECC brick = 56 sheets Pb + 57 photographic emulsions 12 M emulsion films and 12 M thin lead foils by Fuji Film (Japan) JLGoslar (Germany) 1 mm t n 2 emulsion layers(44 m thick)poured on a200 m plastic base Pb Emulsion layers Résolution (microtracks) spatial : 0.06 µm Angular : ~ 2 mrad This technology allows a spatial micrometric resolution, and a 3D reconstruction of particle tracks, necessary fortdetection 10.2cm 2mm 12.5cm Vertex position resolution : ~1µm in transverse plane The most precise tracker 6mm - Measurement of hadrons momenta by MCS - dE/dx pion/muon separation at low energy - Electron identification and energy measurements for electrons and photons Reconstructed electronic shower n 8 cm 12.5 cm 10 cm 8.6 kg

  8. BAM(Brick Assembling Machine) Automatic lead/emulsion piling in a dark room (500-700 bricks/day) Brick production and insertion 30000 The BMS(Brick Manipulator System) one robot on each side of the detector 25000 Daily total 20000 15000 Insertion and extraction of bricks following intelligent procedures. 10000 5000 Begining 2007 now Target preparation

  9. Detector today : electronics fully instrumented and tested Brick filling on the way : 27000 Bricks already inserted LNGS Hall C

  10. OPERA event analysis procedure Neutrino nm events in OPERA-like bricks (PEANUT test-beam) Brick finding : selection of the interaction brick provided by time correlation of electronic detectors Emulsion Development of candidate bricks at Gran Sasso (surface facilities)  31 tracking scintillator planes (TT)/super modules Salerno scanning lab analysis Emulsion shipment Trigger(>99%) +Brick finding(7080%) NUMI beam at low energy configuration Emulsion Scanning with automated microscopes : Scanning labs performance tests and improvements with : -p/e test-beams -nm test-beam -cosmic runs 15 laboratories in Europe and Japan Example of a vertex in emulsion p.h. 0 max 20-30 bricks extracted / day

  11. First OPERA results with CERN neutrino beam Beam events cosmics Positive electronic tests during first beam run (August 06 : 0.084 1019 integrated pot) ninteraction in magnet (Fe) • More than 300 registred events correlated in time with beam : interactions inside the rock and inside the detector (TT and spectrometers) First events from the CNGS neutrino beam detected in the OPERA experiment R. Acquafredda et al 2006 New J. Phys. 8 303 Next CNGS run : Autumn 2007

  12. Muon track inside emulsions First OPERA results with target bricks from cosmic run(May 07) < 1 event per day inside the acceptance ! ~20 ‘good’ bricks per month April 17th- May 15th : ~30 bricks extracted 18 scanned 8/18 muons already found in emulsions Cosmic muons in OPERA detector (ray bandle) • Prediction accuracy : • Δx = 5.5 mm (along the tray) • Δy = 0.4 mm (vertical direction) • Δθx = 16.6 mrad • Δθy = 24.8 mrad first data confirm the good accuracy of the ED predictions

  13. Conclusion OPERA is the first experiment for nt appearance in a nm beam Hybrid detector with passive lead target and active electronic detectors Electronic parts fully instrumented and tested 27000 Bricks yet inserted in the detector - full detector expected for summer 2008 First results -Neutrino events have been observed in emulsions from PEANUT NUMI test-beam -CNGS beam run in August 2006 : electronic detectors gave good results -Cosmic run : brick candidate extraction ; scanning and analysis on the way to validate the full analysis chain Future Next CNGS beam run : Autumn 2007 with ~60000-70000 bricks and a beam intensity of 0.43 1019 integrated pot 180 expected events in bricks

  14. 1.7 m 6.9m 64 strips/module 2 x 256 strips LNGS Tracker wall Target Tracker ●Trigger: > 99% ●Brick finding :  7080% ● Initiate muon tagging Plastic scintillator strips (AMCRYS-H, 6.7m x 2.6cm x 1cm) readout by Kuraray WLS fibres + Hamamatsu PMT’s (64 channels) Reconstructed cosmic track

  15. Muon spectrometer coil M ~ 950t 12 Fe slabs (5cm thick) 8.2 m B= 1.55 T 2 cm gaps slabs RPC’s base Drift tubes Inner Tracker: 11 planes of RPC’s 21 bakelite RPC’s (2.9x1.1m2) / plane Precision tracker: 6 planes of drift tubes diameter 38mm, length 8m 4 staggered layers / plane, each layer consisting of 168 tubes efficiency: 99% space resolution: 300µm  identification:  > 95% (TT) p/p < 20% , p < 50 GeV/c misidentified  charge prob.  0.1  0.3%

  16. Scanning : emulsion digitisation 16 tomographic images = 45µm Field of vue 300µm 300µm 2D images processing 3D reconstruction of particle tracks 2 emulsion sides (45 mm) speed : 20cm²/hour/emulsion side Résolution (grains) spatial : 0.06 µm Angular : ~ 2 mrad 1 plastic base (200 mm) 1 emulsion sheet (2 sides) : 12h scanning - ~5Go Reconstruction of micro-tracks (45µm) 15 scanning laboratories in Europe and Japan

  17. PEANUT : OPERA test-beam at FERMILAB goal : to observe neutrino interactions in OPERA bricks Detector placed in the front of the MINOS near detector: -4 walls of 3*4 OPERA bricks exposed to NUMI beam (nm ) in « low energy » configuration (<E>=10GeV, Epeak=3GeV ) -DONUT SFT (scintillators) between each wall Brick piling in dark room 5 nm events/brick /day expected bricks exposed ~20days Exposure time: October 18th 2005 -> Mars 1st 2006 total 160 Bricks made, exposed and developped developper SFT-emulsions alignment Neutrino reconstruction in emulsions ~500µm spatial resolution ~5mrad angular resolution Salerno scanning lab analysis

  18. m232 = 2.5 x 10-3 eV2 23 = 45° nominal CNGS beam 5 years Combined fit of Ee, Evis, (pt)miss 2.5x10-3 eV2 sin2(213)<0.06 13 < 7.1º   eoscillation search 90% C.L. limits on sin2(213) and 13 :

  19. Reason for rupture : Alignment errors and geometry too rigid Vibration Accident during assembly (?) Improvements of new design drain connection : Absorb better any misalignment errors Water and vapour tightness maintained Rigourous Quality during assembly Reparing on the way for Autumn 2007 October 27th 2006 shutdown : leaking Drain Connection in the reflector cooling system Outer conductor (Al) Ceramic insulator (500V) (brazed to the Ti joints) Clamps for vapor tightness Titanium joints Rupture point – leak!! Bellows to give (some) flexibility

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