1. Construction, Installation and Commissioning of a High- Efficiency and High-Resolution Straw Tube Tracker for the Experiment ●Introduction ○B-physics at LHCb ○The LHCb experiment ●The LHCb Outer Tracker ○Design and construction ○Installation and commissioning Fabian Jansen (Nikhef) On behalf of the LHCb Outer Tracker group 11th Pisa meeting on advanced detectors La Biodola, Isola d’Elba (Italy), May 24-30 2009

2. May 25, 200911 th Pisa Meeting on Advanced Detectors 2 / 28 B-physics ●The physics of hadrons containing b-quarks 1.CP-violation (Charge-Parity asymmetry) with B-mesons ○measurable through B/anti-B mixing and decay 2.New physics with rare B decays ○B decays with small conventional branching fractions involving loop diagrams ○New physics may contribute at the same scale as conventional physics V tb Nobel prize 2008: 1.spontaneous symmetry breaking + 2.at least three families of quarks = possible CP violation B mixing new physics? K*K* B0B0 μ+μ+ μ-μ- b s rare decay B 0 → K* μ + μ -

3. May 25, 200911 th Pisa Meeting on Advanced Detectors 3 / 28 B-physics at LHCb ●The LHC will act as a B factory with large b-quark production rate ○σ bb ~ 500μb for pp collisions at  s = 14TeV ●B hadrons are produced predominantly forward/backward ●LHCb ○forward spectrometer (10-300 mrad) ○dedicated to B physics ○“modest” luminosity L~ 2  10 32 cm -2 s -1 ○expected 10 12 bb/year (10 7 sec) 100  b 230  b p p b b p p collision 250mrad

4. May 25, 200911 th Pisa Meeting on Advanced Detectors 4 / 28 LHCb detector: overview ●One-arm forward spectrometer: subdetectors cascade in beam direction proton beam collision point ~1 cm B proton beam

5. May 25, 200911 th Pisa Meeting on Advanced Detectors 5 / 28 LHCb detector: vertex locater ●contains the pp-collision point ●precise determination of primary and secondary vertices (B lifetime) ~1 cm B

6. May 25, 200911 th Pisa Meeting on Advanced Detectors 6 / 28 LHCb detector: RICH1,RICH2 ●Particle IDentification; kaon-pion separation

7. May 25, 200911 th Pisa Meeting on Advanced Detectors 7 / 28 LHCb detector: calorimeter system ●particle identification; electron, photon, hadron ●trigger (at 40MHz)

8. May 25, 200911 th Pisa Meeting on Advanced Detectors 8 / 28 LHCb detector: muon system ●muon tracking ●trigger (at 40MHz)

9. May 25, 200911 th Pisa Meeting on Advanced Detectors 9 / 28 LHCb detector: tracking stations ●charged particle momentum determination ●TT before magnet, Inner and Outer Tracker after magnet

10. May 25, 200911 th Pisa Meeting on Advanced Detectors 10 / 28 OT expected occupancy: Average = 4.5% Hottest region = 9% Outer tracker performance requirements ●High speed ○25ns bunch crossing cycle ●Momentum resolution (Δp/p) better than 0.5% (2-100GeV tracks) ○precise (B-)mass reconstruction ○=► spatial resolution less than 200μm ●Occupancy below 10% ○efficient track reconstruction ●High efficiency ○efficient B reconstruction beam pipe and Inner Tracker expected J/ψ mass distribution σ=11MeV!

11. May 25, 200911 th Pisa Meeting on Advanced Detectors 11 / 28 The Outer Tracker consists of 3 stations ~0.5m apart ●Station ○2 support frames (C-frames) mounted vertically with 2 layers of detector modules ○=► 4 layers of modules with orientation 0 0,+5 0,-5 0,0 0 ○Every C-frame is in two halves that can be moved horizontally in and out around the beam pipe ●Layer ○14 type F modules; full height ○4 type S modules; half height outside the hot region Outer Tracker module design and production 2400 mm Type F S1 3070 mm S3 S2 2900 mm 0 0 +5 0 -5 0 Inner Tracker

12. May 25, 200911 th Pisa Meeting on Advanced Detectors 12 / 28 Outer Tracker module design and production ●Module ○2 staggered layers of 64 straw tubes ○split in electrically independent upper and lower sections with Front End electronics on both sections ○1module: X/X 0 = 0.37%! ●Straw ○5mm radius ○25μm anode wire at 1550V ○Ar(70%)/CO 2 (30%) module top view aluminum laminated kapton wound on carbon doped kapton-XC 4800 mm 340 mm

13. May 25, 200911 th Pisa Meeting on Advanced Detectors 13 / 28 Outer Tracker module design and production ●2004-2005: OT module production ● Quality assurance during production ○wire tension (<7%) ○wire position (<100μm) ○dark current (<10nA at 1600V) ●Quality assurance after production ○gas tightness (<1mbar/minute) ○dark current (<10nA at 1600V and Ar(70%)/CO 2 (30%) ) ●Detector response to 90 Sr source; full scan (every cm) of all OT modules ●Module production summary ○dead channels: disconnected shorts (0.6‰) ○“noisy” channels: high dark current (0.7‰), often cured after HV training Cracow: all straw-support panels Warsaw: 124 type S modules Heidelberg: 62 type F modules Nikhef: 130 type F modules Detector Module mass construction ~ assembly of: - 56,000 straws - 56,000 wires - 200,000 soldered joints - 620 panels - 185 F and 124 S Modules LHCb note: lhcb-2004-078

14. May 25, 200911 th Pisa Meeting on Advanced Detectors 14 / 28 OT Front End electronics design and production ●HV circuit board ○330 pF capacitors decouple signal from HV ○embedded capacitors reduce leakage currents ●ASDBLR amplifier ○discriminate signal against threshold ○high speed through elimination of long ion tail by shaping and baseline restoring of signal; dead time ~20ns ○low noise through differential logic swing ○low threshold =► good efficiency & resolution ●OTIS time-to-digital converter ○25ns LHC bunch clock into 64 TDC bins ○incorporate up to three BX drift time ●GOL ○Transfer of data of 128 channels (+headers) via optical fiber at 1.6Gb/s See poster: The FE Electronics of the LHCb Straw Tube Tracker

15. May 25, 200911 th Pisa Meeting on Advanced Detectors 15 / 28 OT Front End electronics design and production ●2005-2008 OT FE electronics production ●All components tested and selected individually before assembly ●All FE boxes tested after assembly on ○threshold characteristics ○timing behavior ○noise and cross talk ○trigger latency response threshold scan insensitive channels ASDBLR’s replaced nonlinear channel OTIS replaced All Front End electronics components with bad characteristics/behavior/response were replaced! LHCb note: lhcb-2007-122 linearity scan rejected components

16. May 25, 200911 th Pisa Meeting on Advanced Detectors 16 / 28 Test beam at Desy ● Beginning of 2005: beam test at Desy ● First four half-length OT modules ● Final prototype FE electronics LHCb Note: lhcb-2005-076 ●Efficiency ●Resolution ●Noise & Cross Talk ●High Voltage ●Amplifier threshold ●Position along straw VS

17. May 25, 200911 th Pisa Meeting on Advanced Detectors 17 / 28 Test beam results (1) r (mm) Drift time (ns) RT-relation 2.45 mm r (mm) Efficiency efficiency profile next slide  resolution and efficiency for different HV and amplifier threshold results for 1550V HV, 800mV threshold

18. May 25, 200911 th Pisa Meeting on Advanced Detectors 18 / 28 Test beam results (2) 100 0.2 0 0 0.6 HV(V) 1400 1550 1200 1400 Good efficiency and resolution for HV > 1550V ε  98% σ  200 µm oCorresponds to Gain > 50,000 Resolution (mm) Efficiency

19. May 25, 200911 th Pisa Meeting on Advanced Detectors 19 / 28 Outer tracker module installation (1) bridge beam pipe module support frame (C-frame) 2x9 detector modules 4x9 FE boxes cooling, gas Low Voltage, High Voltage, etc.

20. May 25, 200911 th Pisa Meeting on Advanced Detectors 20 / 28 Outer Tracker module installation (2) ●2006-2007: Assembly of modules into C-frames and installation of C-frames in detector ●Before assembly of modules, C-frames tested for ○gas tightness of gas distribution system <1mbar/minute at 10mbar CO 2 ○High Voltage leakage currents <10nA/RMS<1nA ○Low Voltage connections OK ○optical fiber attenuation<30dBm ●After assembly of modules into C-frame,modules tested for ○gas tightness: <1mbar/minute & matching production ○High Voltage leakage currents<100nA/channel at 3 minutes 1.8kV-CO 2 ●Functionality test with 55 Fe source ○>2700 straws (~½OT) individually tested ○13 dead channels; 11 known at production ●2008: Installation of FE electronics LHCb note lhcb-2008-033

21. May 25, 200911 th Pisa Meeting on Advanced Detectors 21 / 28 Outer Tracker commissioning overview ok FE not installed I2C problem BxID mismatch QPLL not locked other problem optical link problem desynchronisation all TELL1 OK this is a snap shot, work is ongoing!

22. May 25, 200911 th Pisa Meeting on Advanced Detectors 22 / 28 Data taking (1) ●During the last months OT was taking data in global LHCb commissioning ○random and calibration triggers (test pulse possibility) ○cosmic muons triggered by CALO/MUON ○“media day” (beam!) media day

23. May 25, 200911 th Pisa Meeting on Advanced Detectors 23 / 28 Data taking (2) ●Look at various type of data with various goals ○Random trigger for noise, FE debugging, … ○Calibration test pulse trigger for threshold characteristics, timing behavior,… oCosmics trigger for ○t 0 calibration/time alignment ○ RT calibration ○ Alignment ○track reconstr. ○… cosmics event Next slides: first t 0 & RT calibrations with cosmics

24. May 25, 200911 th Pisa Meeting on Advanced Detectors 24 / 28 Cosmics data (1) ●Use calorimeter to trigger cosmic muons ●Correct for downstream (early OT hits) or upstream (late OT hits) ●Correct for Time Of Flight and wire propagation time TDC = t cosmic + t TOF + t drift + t prop + t 0

25. May 25, 200911 th Pisa Meeting on Advanced Detectors 25 / 28 ●t 0 calibration with cosmics: a first analysis Cosmic data (2) Faulty CLK fan-outs, now replaced! module t 0 (ns) module average t 0 (ns) module <3ns variation in t 0 ’s!

26. May 25, 200911 th Pisa Meeting on Advanced Detectors 26 / 28 Cosmic data (3) ●RT relation with cosmics: a first analysis RT-relation in beam test RT-relation from cosmics calibration with cosmics ongoing work!

27. May 25, 200911 th Pisa Meeting on Advanced Detectors 27 / 28 Summary ●LHCb will be ready to collect data with its full detector as LHC turns on: oTest of Charge-Parity asymmetry oprobe rare B decays ●Tracking system performance of crucial importance oOuter Tracker consisting of straw-tubes modules oAll OT modules and electronics built and tested Quality Assurance during production Beam tests ●All OT modules and electronics installed and re-tested in situ oCommissioning well advanced Electronics debugging Cosmic trigger for OT commissioning: track reconstruction, T0 and RT calibration, alignment, etc Beam for B physics

28. May 25, 200911 th Pisa Meeting on Advanced Detectors 28 / 28