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Commissioning and perspectives of the LHCb Experiment

Commissioning and perspectives of the LHCb Experiment. W. Baldini, INFN Ferrara, on behalf of the LHCb Collaboration XCIV congresso SIF, Genova 22-27 Sett. 2008. Outlook. The LHCb experiment Subdetectors commissioning Global commissioning Time alignment Space alignment

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Commissioning and perspectives of the LHCb Experiment

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  1. Commissioning and perspectives of the LHCb Experiment W. Baldini, INFN Ferrara, on behalf of the LHCb Collaboration XCIV congresso SIF, Genova 22-27 Sett. 2008

  2. Outlook • The LHCb experiment • Subdetectors commissioning • Global commissioning • Time alignment • Space alignment • A possible running scenario… W. Baldini, INFN-Ferrara

  3. The LHCb experiment • CP violation and rare decays of b (and c) hadrons • Constraint unitarity triangle and search for new physics • Luminosity ~ 2 x 1032 cm-2 s-1(not focussed beam) • Max propability of one interaction/bunch, but multiple interaction identification needed • sb b-bar≈ 230 mb , spp≈ 80 mb • ~ 30 long tracks / primary vertex: • efficient trigger • precise tracking • powerful PID W. Baldini, INFN-Ferrara

  4. b The LHCb Detector b • Single arm forward spectrometer • Angular acceptance 250 mrad x 300 mrad (bending plane), projective geometry • Precise tracks and vertex reconstruction: VELO, Tracking System • Excellent PID: RICH(1-2), Calorimeters, Muon System • Selective and flexible trigger: • VELO, Calorimeters, Muon W. Baldini, INFN-Ferrara

  5. M5 M4 M3 M2 MAGNET ECAL SPS HCAL RICH2 TS RICH1 VELO TT Installation of all sub-detectors is complete except for M1 (installation starting soon..?) The LHCb detector W. Baldini, INFN-Ferrara

  6. M5 M4 p M3 M2 MAGNET ECAL SPS HCAL RICH2 TS RICH1 VELO TT IP p VErtex LOcator • primary/secondary vertices recostruction • Multiple interaction suppression (pile-up) • Absolute luminosity measurement • 30 mm impact parameter resolution • 40 fs B0s proper time resolution W. Baldini, INFN-Ferrara

  7. f p r IP p Vertex LOcator • 2 movable detector halves (retracted during beam filling) • 21 stations (+ 2 “pile up”) per half detector • r,f measurement per each station • pitch: r→ 30-100 mm , f → 40 - 100 mm W. Baldini, INFN-Ferrara Pile-up stations

  8. Subdetectors commissioning: VELO • Main issue is the space alignment (at micron level) • first detector standalone alignment performed with a test beam on 10 modules to test also the software for real tracks alignment (based on millipede) • Measured resolution: • r: 9 – 25 mm • f: 9 - 20 mm • Will improve further taking into account X-talk • First measurements done exploiting particles from LHC injection tests confirms results, precise alignment will be performed as soon as more tracks are available • 99.2% operational and ready for beam • New test beam @ FNAL is forseen to better understand radiation effects on sensors and a possible high luminosity upgrade mm DX z (mm) mm DY z (mm) First alignment measurements for VELO right half for two sets of data (tracks on VELO from injection tests) W. Baldini, INFN-Ferrara

  9. Outer Tracker OT Inner Tracker IT T - Tracker Tracking System: IT - OT - TT M5 M4 MAGNET M3 M2 ECAL SPS HCAL RICH2 IT-OT RICH1 VELO TT • IT: silicon detector, 4layers/station , 200 mm pitch, 2% of area but 20% of tracks • TT: silicon detector,2 layers/station, large area (7 m2), pitch ~ 200 mm • OT: 4 double layers of straw tubes (d=5mm) per station, drift gas: Ar(70%) CO2(30%) • Average reconstruction eff: 95% (B decays) W. Baldini, INFN-Ferrara

  10. IT status T1 T2 IT3 T3 IT2 A C IT1 TT status Sub detector commissioning: Inner & Trigger Trackers Run 31557 IT data Run 31557: 5 hours cosmic run160 k-events, Aug. 29-th • IT: • 96.4% of the detector is working properly (1.9% dead channels, 1.7% noisy) • First approx time alignment done thanks to LHC injection test tracks • Internal spatial alignment at measured at mm level, to be refined with first collisions • TT: • 99% of the detector is operational, 91% decoded, connection to be improved Run 31557 TT data % of TT decoded channels W. Baldini, INFN-Ferrara

  11. before heating after heating Sub detector commissioning: Outer Tracker • The detector is operational at 95% • First approx. time and spatial alignment ongoing with cosmics (no drift time) • Loss of efficiency in some modules was observed after moderate irradiation, due to Araldite outgassing (not an aging problem). • The Problem has been extensively studied, various beneficial effects found: • heating • Adding in the mixture small amount of (N02) • HV training • Re-test and recovery of bad modules under way OT- alignment with cosmics Dx OT hitmaps W. Baldini, INFN-Ferrara

  12. M5 M4 M3 M2 MAGNET ECAL SPS HCAL RICH2 TS RICH1 VELO TT RICH-2 RICH system • RICH1 Aerogel: 1 - 10 GeV •  C4F10 : 10 – 70 GeV • RICH2 CF4 : beyond 100 GeV • Pixelated (0.5x0.5 mm2) HPDs readout • Kaon ID: k→k 97% , p →k 5% RICH-1 W. Baldini, INFN-Ferrara

  13. before correction after correction s ~ 1.0 mm s ~ 0.7 mm Single photon accumulated image taken shining from a projector (the same used for the magn. distortion) on the C-side of RICH2. The light level over the whole surface is ~100 pe per event. Subdetectors commissioning:RICH system • For the moment filled with C02 , change to right gases for first collisions • At present the detector is fine apart from a vacuum leak in some HPDs (42/484, 20 already replaced) • Magnetic calibration of HPDs is ongoing, photodetector plane resolution better that a mm W. Baldini, INFN-Ferrara

  14. M5 M4 M3 M2 MAGNET ECAL SPS HCAL RICH2 TS RICH1 VELO TT Calorimeters: Hcal, Ecal, PS,SPD • Ecal: shashlik, 6k cells • Hcal: tile (Fe+scint.), 1.5k cells • PS/SPD: lead/scintillator, 12k cells • e,g , h, PID + L0-Trigger W. Baldini, INFN-Ferrara

  15. Subdetectors commissioning: Calorimeters • Internal time alignment ongoing with LED (each single cell equipped, to mimic a particle signal) and with cosmics: • LED internal time alignment: • Hcal  RMS ~ 1.3 ns • Ecal  RMS ~ 2-4 ns • Cosmics internal time alignment: • Hcal  ± 4 ns • Ecal  ± 3 ns • PS/SPD aligned within 5 ns • Hcal scan with a radioactive source (137Cs ) showed only two dead cells • Relative time alignment among CALO detectors (PS/SPD, Ecal, Hcal) is ongoing exploiting cosmics • Beam injection tests were also very useful to check the detector…. Source scan of Hcal SPD event during injection test W. Baldini, INFN-Ferrara

  16. M2-M5 M5 M4 M3 M2 MAGNET ECAL SPS HCAL RICH2 TS RICH1 VELO TT M1to be installed Muon System • 5 stations (M1…M5), 4 regions/station (R1…R4) • 1368 MWPCs + 12 GEMs (innermost part of M1) • two movable structures • L0 trigger: high pt , m-ID W. Baldini, INFN-Ferrara

  17. M3 M2 M4 M5 Bunch of particles from injection test Subdetectors commissionig: Muon System M5 station • Very large area detector (435 m2), 1380 single chambers to be installed, connected, aligned, tested….. • “Hardware” detector alignment completed in June: <3 mm misalignment from surveyers and software confirmed with cosmics • Reproducibility after opening/closing half stations better than 5 mm • Internal time alignment ongoing with cosmics and particles from LHC injection tests • During LHC injection test about 92% of the detector detected 19/19 bunches  very first indication of a good efficiency W. Baldini, INFN-Ferrara

  18. Front-end Velo Calo Muon Trackers RICH L0 Trigger Y/N Y/N Trigger and Fast control Readout network trigger datafast controlfull data Event Filter Farm 1000-2000 nodes CPU CPU CPU Trigger DAQ Trigger System 40 Mhz (visible collisions 12 MHz) • L0 trigger (Hardware): • high pt from Muon • high E from CALO • no pile-up L0 full detector readout: 1 MHz • High Level Trigger (software): • L0 confirmation • high IP events • full event reconstruction HLT on tape2 kHz Event size: ~ 35 kB W. Baldini, INFN-Ferrara

  19. LHCb Global Commissioning Global commissioning is ongoing since few months. Subdetectors joined the global commissioning phase as soon as ready… exploiting cosmics for the large area detectors (OT, Muon, Calorimeters) and particles from LHC when available (beam gas interactions, injection test particles….) W. Baldini, INFN-Ferrara

  20. Global commissioning:Time Alignment Calo time distributions • rough time alignment Calo-Muon is ongoing with cosmics and particles from injection tests • Dedicated trigger for cosmics (SPD multiplicity and muon M3 with wide time window) • Muon and Calorimeter are aligned within 1 bunch crossing (~16 ns) • For precise time alignment we have to wait for first collisions (take into account correct TOF from IP) Muon time distributions Muon Calo W. Baldini, INFN-Ferrara Muon-Calo time distributions

  21. OT- cosmics Residual’s mean [mm] Track type M2 C side M4 C side X All Forward backward 1.8±0.6 1.1±0.7 0.7±0.8 0.32±0.32 0.12±0.41 0.1±0.5 Y All Forward backward -1.2±1.1 -3.2±1.5 0.5±1.7 0.28±0.48 -2.9±0.6 3.3±0.7 Global commissioning: Spatial alignment • The strategy: • internal sub-detectors alignment (with cosmics if possible or with first interactions) • Tracking system (VELO-TT-IT-OT) relative alignment with tracks and B=0 • Rich – Calo - Muon alignment wrt tracking system • VELO- TT alignment ongoing, first results: ~ 300 mm, VELO- IT more problematic due to more noise • some preliminary measurements with cosmics for OT and Muon show mis-alignments of few mm • tracks from IP needed for precise alignment, waiting for first collisions Dx VELO- IT alignment residual distribution VELO- TT alignment residual distribution W. Baldini, INFN-Ferrara Muon-cosmics

  22. Sept. 10-th 2008 LHC startup Some reconstructed tracks from OT- Calo – Muon during the LHC startup on Sept. - 10th W. Baldini, INFN-Ferrara

  23. Very first beam from LHC… Calorimeters Rich2 LHCb Control Room Outer Tracker Muon W. Baldini, INFN-Ferrara

  24. A possible Running Scenario… • LHC plans will be more clear in the next weeks…. • 2008 possible scenarios: • 2 months shutdown + some beam (december??) • No beam during 2008 • Start as soon as area is accessible M1 installation and some subdetectors intervention… • End 2008 beginning 2009: first collisions @ L ≈ 1031 cm-2s-1 • Precise time / spatial alignments • calibration of the apparatus and efficiency calculation (e.g unbiased samples of Ks and L from min. bias and J/y → mm with trigger on one hight pt muon ) • 2009: data taking @ L ≈ 2 x 1031 cm-2s-1 , first results on CP violation and rare decays (Bs→ J/ψf , mm ) • 2010 expected ≈ 2 fb-1 per year, full physics program. Expected about 10 fb-1 by 2013. • 2013 LHCb upgrade….? W. Baldini, INFN-Ferrara

  25. Conclusions • The LHCb detector is in rather good shape • Subdetectors have been commissioned and are working at ≈ 95% level, few issue to be solved but no major problems • Given the last LHC events we will probably continue in the next weeks to improve as much as possible the performances of the detector to be in excellent shape for the first collisions…. W. Baldini, INFN-Ferrara

  26. SPARE W. Baldini, INFN-Ferrara

  27. 2. Beam Absorber (TDI) • Beam Stopper (TED) • Horizontal 12 mrad • Vertical 8 mrad BEAM Beam-2 Beam-1 W. Baldini, INFN-Ferrara

  28. Tracking Performances From MC W. Baldini, INFN-Ferrara

  29. Vertexing From MC W. Baldini, INFN-Ferrara

  30. Luminosity monitor W. Baldini, INFN-Ferrara

  31. RICH W. Baldini, INFN-Ferrara

  32. W. Baldini, INFN-Ferrara

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