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LHCb

LHCb. SAC Review Meeting April 17, 2008 Marcel Merk for the LHCb group. Contents: Velo and PileUp Outer Tracker Software. b-b in LHCb. q b. q b. vertices and momenta (mass) reconstruction effective particle identification ( π , К, μ , е, γ ) triggers. LHCb event rate: 40 MHz

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LHCb

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  1. LHCb SAC Review Meeting April 17, 2008 Marcel Merk for the LHCb group • Contents: • Velo and PileUp • Outer Tracker • Software

  2. b-b in LHCb qb qb • vertices and momenta (mass) reconstruction • effective particle identification(π, К, μ, е, γ) • triggers LHCb event rate: 40 MHz 1 in 160 is a b-b event

  3. The VErtex LOcator in LHCb • Velo “Specials”: • Detectors move to 8mm from beam • Detectors inside vacuum • Cooling with 2-phase CO2 • Silicon strip detector • Reconstruct primary and secondary vertices • Tracking, use R-Phi geometry • Pile-Up Trigger in L0 

  4. The Outer Tracker in LHCb • Straw tube detector • Momentum determination with TT and magnet • Tracking, use XUVX geometry • 3 OT stations: T1, T2, T3 

  5. View of LHCb in Cavern Muon det Muon det Calo’s Calo’s Magnet RICH-2 RICH-2 Magnet RICH-1 OT OT RICH-1 VELO VELO Installation of major structures is complete

  6. VeLo Project Collab.: Heidelberg, MPI, Liverpool, Glasgow, CERN, Lausanne, Syracuse, VU, Nikhef NIKHEF provides Velo deputy projectleader • Nikhef Contributions: • Mechanics + RF • Vacuum control • Motion control • CO2 cooling • Pile-Up trigger • Commissioning

  7. The Detector Vacuum box (“RF Box”) • Thin, leak-tightcorrugated RF foilbetween sensors and beam 30 mm • Superplastic pressing of 300 mm Al foilwith hot gas • Welding into a vacuumtight box

  8. The Detector Vacuum box (“RF-box”) • Dp < 5 mbar at all times! • Leak rate between beam and detector volumes determined to be : 3.2x10-5 mbar.l/s @ 1 mbar He • No problem for normal operation, venting and evacuation • Risk: saturation NEG coating during installation • Replacement in 2009 • R&D ongoing for improved production method

  9. Half Velo-detector in assembly lab • Operation of both detector halvestested in assembly lab

  10. Installation (Oct 2007)

  11. CO2 cooling system • 2-phase CO2 cooling system • Low mass • Radiation hard • Redundant / backup system Only passive components in radiation area Detector temperature (evaporator) is controlled by pressure in accumulator Isothermal because of liquid-vapor mixture accumulator cooling plant shielding wall VELO detector 2-phase CO2 loop condenser -25 ‘C restriction -25 ‘C evaporator R507a chiller pump 60 m concentric tube liquid liquid -40 ‘C 2-phase -25 ‘C

  12. Cooling Plant Installation (summer 2007) Controls PLC accumulators Freon Unit CO2 Unit

  13. Velo Cooling tests under vacuum T (oC) Performs well 20oC 10oC 0oC -10oC T= -10oC -20oC TRF-foil≈ +9oC Time (hours)

  14. Vacuum • During pumpdown and venting: • p < 5 mbar between beam-vacuum and detector-vacuum

  15. Effect of Cooling on Vacuum 10-2 Reach p < 10 -8: OK P [mbar] pdetector 10-5 T= -10oC TRF-foil≈ +9oC 10-8 pbeam Time

  16. Velo Commissioning • All cables and connectors checked • (20% LV modules missing) • Cooling, Vacuum and Motion being finalized • Hardware interlocks tested • Basic ECS software available, continuously being improved • First R-f station been powered up and read out under bias voltage (80 V): Outlook Velo (May-June): • Power up C-side modules under neon • Operate C-side under vacuum • Repeat for A-side detector half • Then look forward to beam… Noise level OK

  17. Pile-Up detector • 2 dedicated R-stations provide: • 1,2,n vertices for each bunch crossing • luminosity per time interval • All detectors/cables/fibers connected • Datapathestablished (apart from Output Board) • Final test of connections in May • Implementation in Trigger/DAQ to be worked on • Test with Level-0 decision unit planned in June • PVSS work ongoing Analog Tell1 digital tell1 Hybrids kapton cables repeater boards transition boards optical boards VEPROB boards output board L0DU @IP8

  18. Outer Tracker Project Collab.: Dortmund, Heidelberg, Warsaw, Cracow, Bejing, VU, Nikhef NIKHEF provides OT project leader • Nikhef Contributions: • Production and Installation: • mechanics & electronics • Infrastructure: • frames and support bridge • Quality Assurance • Commissioning • Irradiation Studies

  19. Detector Installation - completed Detector Modules Cooling and Gas LV,HV, ECS/TFC.. • Alignment: • Stations positionedwithnox-y-zrotations to +- 0.5 mm • xyz of modules known to +- 0.5 mm • Reproducibility of open-close ~ 30 mm (except 1 C-frame) • Final x-alignment of C-frames using RASNIK (RASNIK installation completes in April)

  20. OT Electronics . • 80% detector is equipped and installed • 80% -> 90% is ready for installation • 90% -> 100% • Produced and tested: May • Installed: June • 100% -> 110% • Finished after summer C-frame equipped with FE boxes

  21. OT Commissioning • Testingindividualchannelswith a source: 21 bad wires out of 32040 • DAQ: OT has been succesfullyincluded in globalcommissioning runs • Cosmics: Cosmic tracks and showers have been observed… Cosmic trigger in OT

  22. Ageing Phenomenon Ratio Plot: Iafter/Ibefore Carbon deposit on the surface Gas flow • Gain loss “in the neighborhood” • of the irradiation point: Croissant? Bean? Kidney? • Only at moderate intensity • Upstream of gas flow A real surprise – this was not seen in the aging tests performed over the last years with test modules

  23. Ageing: The Cause Put fresh glue (AralditeAW103, HY991) at straw entrance of Aluminum test module Test module: 17 hrs, 2 mCi TraBond 558 hr, 20 mCi Build full-scale module with different glue: TraBond 2115

  24. Beneficial Treatments L 1) Flushing: • PreventingTreatments: 1) Long term flushing 2) Heating of the modules 3) Lowering the gas flow 4) Adding O2 to the counting gas  Gain loss (%) ½ year ½ year 2) Heating (Lab):  Flushing Time (weeks) No heating: 20 hrs2mCi 90Sr With heating: 325 hrs2mCi 90Sr

  25. Recovery Treatment  Relative Gain  Irradiation Time (hours) 1st HV training 2nd HV training 3rd HV training • HV training (24 hours, 1900 V, G~106) • Darkcurrent ~10 m A/wire • Wireinspectionpromising: • no carbon depositsdespitelargecurrents Before HV training Trained half After HV training Non-trained half

  26. Outer Tracker Outlook OT • Detector installed and aligned • Electronics production being finalized • Commissioning underway • Irradiation resistance studies ongoing: • Detectors being flushed and heated • Investigating HV training procedure • Further testing of ``TraBond module´´

  27. Software: Reconstruction, Trigger & Physics NIKHEF provides Trigger deputy project leader (HLT implementation) • Nikhef Contributions: • Kalman Filter track fitting • Software Alignment: • Framework, Geometry, Kalman filter implementation • HLT implementation • DaVinci and LoKi physics frameworks

  28. Display of LHCb simulated event 28

  29. Key measurements – NIKHEF group s b b s s b Looking for effects of new physics in the flavour sector: • CKM Metrology: • Amix: Bs→ Dsp Dms ACP: Bs→ Ds Kg-fs • ACP: Bs→ J/y f fs • Rare Decays: • Br: B(s)→mm • Afb: B0 →K*mm , b →s mm “Box” “Penguin” 4 “teams”: each with 1-2 staff, 1 postdoc, 2-3 students • Well matched to our activities: • VeLo and OT construction • Track reconstruction

  30. Kalman Track Fitting and Alignment z • Reconstruct tracks including multiple scattering. • Tracking in realistic (misaligned) geometry. • Simultaneous detector element alignment fit and trackfit Track c2/dof: Dimuon mass resolution: • Unaligned • O Aligned • Default • Unaligned • O Aligned • Default J/y peak

  31. Example: Bs→ J/y f . signal backg sum • Simultaneouslikelihoodanalysis in time, mass, angular distribution domains time mass cosqf cos qtr ftr

  32. Theses b-physics • Theses on LHCb: • (2001) N. Zaitsev Pile-up and Bs→J/yf • (2002) R. v.d. Eijk OT and tracking • (2003) R. Hierck Tracking and Bs→DsK/p • (2004) N. v. Bakel Velo and Bs mixing • (2005) S. Klous Velo and Bs →J/y f • (2005) J. v. Tilburg Tracking and Bs→Ds K/p • (2006) B. Hommels Tracking and Trigger • (2007) J.Nardulli Reconstruction of two body B decays in LHCb • Theses on Hera-B: • (2002) M. Bruinsma J/y in pA • (2002) W. Hulsbergen Track reconstruction • (2003) M. Mevius B cross-section • (2005) H. Wahlberg B cross-section • (2006) A. Sbrizzi B X-section & pentaquark • Thesis on Babar: • (2006) M.Baak CKM angle gamma

  33. The B-Team The “technical” Beauties! (the real backbone) The B-team The mad young geniuses: The Muscles: Those who love it when a plan comes together (the Planners): Nikhef-evaluation

  34. Summary • Velo • Cooling, vacuum, motion control are “ready” • The devil is in the (unforseen) detail • PileUp detectors installed, trigger implementation requires effort • New RF-boxes being produced • Outer Tracker • Detector installed and aligned • Electronics installation under time pressure • Irradiation studies ongoing with high priority • Software • Reconstruction framework ready • Tracking fitting and Alignment algorithms tested • Selection and physics algorithms being developed • Upgrade • Investigating contributions: • Better RF boxes • Velo module replacement • OT operation under high luminosity • 40 MHz readout electronics

  35. The End

  36. The Scientific Team (NIKHEF, VU) • Scientific Staff: (~9 FTE) • Bauer(0,5 OT), v Beuzekom(0.8, Velo),v/d Brand (0.5, Velo),Bulten(0.5,Phys), Hulsbergen(1, Reco), Jans(1, Velo),Ketel(0.5, OT/Velo),Merk(1),Pellegrino(1,OT),Raven (1,Phys), Tuning(1, OT,Phys),de Vries(0.8, Velo),Wiggers(0.7, PileUp/Upgrade) • Post-docs: • Belyaev(Phys),Kazu(Velo/Phys), Palacios (Reco), Serra(Phys), Terrier(OT) , Van Lysebetten(Velo) • Graduate Students: • Amoraal(Reco),Bos(Reco),Jansen(OT),M’charek(OT/Phys), Mous(Velo),Papadelis(Velo),du Pree(Phys), Simioni(OT/Phys),Snippe(Velo), Snoek(Babar),Storaci(OT ),Ybeles-Smit(Phys) • Master Students: • Aaij(Reco),Hooft v. Huysduynen(Phys)

  37. The group • StaffMembers • 12 people (~9 FTE) : 2(30+), 4(40+), 5(50+), 1(60+) • Postdocs • 3 FOM-Nikhef, 1 FOM-PR, 1 NWO-Vidi • TechnicalStaff • 7 (3 OT+4 Velo) MechanicsEngineers, 4 (2 OT+2 Velo) Mechanics Workshop, 8 (3 OT+5 Velo) Electronics, 1 Computing • GraduateStudents • 6 FOM-Nikhef, 1 FOM-BUW, 1 VU, 1 NWO-Vidi • 2 Masterstudents

  38. LHCb experiment in the cavern Offset interaction point (to make best use of existing cavern) Shielding wall(against radiation) Electronics + CPU farm Detectors can be moved away from beam-line for access

  39. b-b in LHCb qb qb Background Supression Flavour tagging Decay time measurement LHCb event rate: 40 MHz 1 in 160 is a b-b event • vertices and momenta (mass) reconstruction • effective particle identification(π, К, μ, е, γ) • triggers

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