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

May 25, 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 -

May 25, 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 ( mrad) ○dedicated to B physics ○“modest” luminosity L~ 2  cm -2 s -1 ○expected bb/year (10 7 sec) 100  b 230  b p p b b p p collision 250mrad

May 25, 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

May 25, 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

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

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

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

May 25, 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

May 25, 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!

May 25, 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 S mm S3 S mm Inner Tracker

May 25, 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

May 25, th Pisa Meeting on Advanced Detectors 13 / 28 Outer Tracker module design and production ● : 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 panels F and 124 S Modules LHCb note: lhcb

May 25, 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

May 25, th Pisa Meeting on Advanced Detectors 15 / 28 OT Front End electronics design and production ● 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 linearity scan rejected components

May 25, 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 ●Efficiency ●Resolution ●Noise & Cross Talk ●High Voltage ●Amplifier threshold ●Position along straw VS

May 25, 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

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

May 25, 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.

May 25, th Pisa Meeting on Advanced Detectors 20 / 28 Outer Tracker module installation (2) ● : 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

May 25, 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!

May 25, 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

May 25, 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

May 25, 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

May 25, 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!

May 25, 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!

May 25, 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

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