Tracking with the LHCb Spectrometer Detector Performance and Track Reconstruction Niels Tuning (Outer Tracker Group LHCb) NIKHEF Amsterdam, The Netherlands Tracking detectors in LHCb Detector construction Detector performance Tracking performance Many thanks to Jeroen van ! Hunen Tilburg 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning LHCb in a nutshell pp with s =14 TeV L = 2.1032 cm-2s-1 1012 b-hadrons per year Both b’s are produced forward: Aim: measure CP violation and rare decays 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning The LHCb Detector 26 June 2006 Imaging2006, Stockholm, Niels Tuning

The LHCb Tracking System Tracking Detectors Vertex Locator Liverpool CERN Glasgow Heidelberg NIKHEF Syracuse Trigger Tracker Inner Tracker Zurich Lausanne Santiago Heidelberg Novosibirsk Outer Tracker NIKHEF Cracow Heidelberg Warsaw 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning Tracks in LHCb 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning Vertex Locator Vertex Tank f sensors R 8mm 42 mm Si sensor n+-on-n 2048 channels, analog readout non-uniform radiation environment 13(0.5) 1013 neq/cm2/yr at R=8(42)mm R sensor: pitch: 38 μm - 103μm thickness: 300μm φ sensor: pitch: 39 μm - 98μm thickness: 300 μm 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning The Trigger Tracker TT = Station before the magnet. Used in the trigger for momentum estimate Fringe field between magnet and VELO Silicon sensors: 9.4*9.6 cm2, 500m thick Long modules of 14 sensors, with max 4 sensors per front-end (Beetle)  55pF Long Kapton cables front-end  sensors 0.12 Tm  z(m) 26 June 2006 Imaging2006, Stockholm, Niels Tuning

The Outer and Inner Tracker Outer Tracker : Inner Tracker 595 cm 450 cm IT occupancy: Hottest region = 2.3% OT occupancy: Average = 4.5% Hottest region = 9% Beam Pipe 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning The Inner Tracker Silicon sensor: p in n-bulk, 198m pitch, 420m and 300m thick. 7.8cm 1mm thick carbon sandwich 25m kapton isolation 11cm 3 stations (T1 – T3) 4 detector boxes per station. Per box: 4 Silicon layers 4x7 modules (1 or 2 sensors each) Kapton hybrid Beetle (0.25 m CMOS) front-end 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning Outer Tracker One large straw tube module: 34 x 490 cm2 4 x 64 = 256 straw tubes 340 mm Total nr of channels: 53.760 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Detector Beam Tests Example: Outer Tracker rt-relation: efficiency profile: Drift time (ns) Efficiency, ε r (mm) r (mm) 2.45 mm 2.45 mm  Resolution and efficiency for different HV and amplifier threshold 26 June 2006 Imaging2006, Stockholm, Niels Tuning

OT Beam Test: Good Detector Performance Good efficiency and resolution for HV > 1520 V ε  98% σ  200 µm Corresponds to Gain>50,000 0.6 Resolution (mm) 0.2 1400 100 Efficiency, ε 1200 1400 1550 HV(V) 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning LHCb Tracking VELO seeds Long track (forward) Long track (matched) T seeds Upstream track Downstream track T track VELO track T tracks  useful for RICH2 pattern recognition Long tracks  highest quality for physics (good IP & p resolution) Downstream tracks  needed for efficient KS finding (good p resolution) Upstream tracks  lower p, worse p resolution, but useful for RICH1 pattern recognition VELO tracks  useful for primary vertex reconstruction (good IP resolution) 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning Tracking Outer tracker station VELO TT T1 T2 T3 26 June 2006 Imaging2006, Stockholm, Niels Tuning

The Expected Tracking Performance 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Expected Tracking Performance (1) Nmeas Ntracks Long tracks ~38 measurements per track Efficiency >95% (for p>12GeV) Ghost rate <7% (for p>12GeV) Robust: track multiplicity x2: efficiency 91% ghost rate 14% efficiency ghost rate 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Expected Tracking Performance (2) IP resolution 1/pt distribution for B tracks 42 mm Vertex Locator Momentum resolution p distribution for B tracks 11cm 500cm Outer+Inner Tracker

Imaging2006, Stockholm, Niels Tuning Conclusions Construction of the LHCb tracking system well advanced Vertex Locator: 8 ‘pre-series’ modules produced (out of 84) Trigger Tracker: 80 half modules in production (need 128) Outer Tracker: All modules produced Inner Tracker: 100 modules produced & 60 are fully tested (need 336) Expected performance (for p>12 GeV): tracking efficiency >95% ghost rate <7% (B-meson decay time resolution is 37 fs !) Detectors are being shipped to CERN for installation! 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Imaging2006, Stockholm, Niels Tuning Backup 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Vertex Locator: Fast and Efficient TDC (ns) S/N ratio Pulse shape 25ns Noise occupancy vs. S/N cut Signal/Noise Cut Overspill vs. S/N cut Signal/Noise Cut 0.1% 25% Radius (cm) Cluster Resolution 20μm 10μm 1cm 4cm Sufficient cluster efficiency (>99 %) Acceptable noise occupancy (<0.1 %) Low overspill (fake cluster rate from previous bunch crossing) (<25 %) Single cluster resolution: 10-20 μm 26 June 2006 Imaging2006, Stockholm, Niels Tuning

Outer Tracker Beam Test Final detector modules Final prototype electronics 6 GeV electrons at DESY Efficiency Resolution Noise Cross talk HV Amplifier threshold Position along straw vs beam See: LHCb-2005-076 26 June 2006 Imaging2006, Stockholm, Niels Tuning