Status of the LHCb Experiment Werner Witzeling CERN, Geneva, Switzerland On behalf of the LHCb Collaboration
Introduction The LHCb experiment aims to investigate CP violation in the B meson decays at LHC and perhaps reveal new physics beyond the Standard Model At s = 14 TeV the pp collisions at LHC will yield abundantly b-hadrons that will be mostly produced in the forward direction The detector is designed as a single arm forward spectrometer for a Luminosity of 2 x 10 32 satisfying following requirements: Efficient trigger for many B decay topologies Good pi/k separation Good decay time resolution Good mass resolution 19/10/2004 IEEE NSS 2004, Rome 2
Layout Single arm forward spectrometer 250/300 mrad v/h Acceptance 10 mrad p-p collisions 19/10/2004 IEEE NSS 2004, Rome 3
Magnet Warm magnet (Aluminium conductor) Coils shaped to follow acceptance window Bdl = 4 Tm Power = 4.2 MW Fe Yoke 1600 tons Commissioning is starting Better photo to come 19/10/2004 IEEE NSS 2004, Rome 4
Beam Pipe Al 0.3 mm 2 mm thick aluminium window Critical components prototyped Final parts in production 19/10/2004 IEEE NSS 2004, Rome 5
Detectors 21 pairs of silicon strip detectors arranged in two retractable halves around the interaction point Two types of 200-300 µm thick sensors: R strips and phi strips with high spatial resolution Fast algorithm for vertex finding used in L1 trigger p Vertex Locator (1) Prototype (2048 channels) Primary vertex resolution (Lvl1 trigger) p σ x =20µm σ z =85µm VELO electronics at this conference: A.Bates N 26-3 19/10/2004 IEEE NSS 2004, Rome 6
Vertex Locator (2) Vacuum Vessel Beam vacuum separated from detector vacuum by thin Aluminium foils (max p 10 mbar) Requires complex vacuum control system Vacuum vessel and other components in construction Interaction point 300 µm aluminium foil 2 mm thick aluminium window 19/10/2004 IEEE NSS 2004, Rome 7
Tracking System (1) 3 stations Outer Tracker (OT) B IT OT 4 planes per station with 0,+5,-5,0 degrees Double layers of straw tubes Readout of straws on both ends Module production has started in three centres, 15% produced (of ~300) TT ~ 5 m Ph [mv] 250 FM_Hd_09 200 150 100 50 Gain uniformity of one module AL-126.5 cm AU-126,5 cm BL-126,5 cm BU-126,5 cm 0 0 10 20 30 40 50 60N ch Talks at this conference: S.Bachmann N 39-4 U.Uwer (poster) N 33-112 19/10/2004 IEEE NSS 2004, Rome 8
Tracking System (2) Trigger Tracker (TT) 1.4 x 1.2 m 2 4 stereo layers 3 and 4 sensors chained on common ladder with Kapton interconnect cable Inner Tracker (IT) 3 stations with 4 boxes each 2 sensors/column 410 µm thick 1 sensor/column 320 µm thick Production of elements starting Talk at this conference: S.Koestner N 26-5 19/10/2004 IEEE NSS 2004, Rome 9
RICH Detectors (1) RICH-1 RICH-2 RICH-1 Radiators: Aerogel and C 4 F 10 Velo exit window and beam pipe are part of gas enclosure π/k separation in the range of 2-100 GeV/c Magnetic shields Beryllium spherical mirrors Photon detector arrays Detailed design ongoing Aerogel at this conference D.Peregod (poster) N 16-101 19/10/2004 IEEE NSS 2004, Rome 10
RICH Detectors (2) RICH-2 Volume ~ 100 m 3 Radiator CF 4 Assembly well advanced Photon Detector Hybrid Photon Detector (HPD) Developed in collaboration with industry ~500 pieces needed to cover 2.6 m 2 HPD talks at this conference: M.Patel N 21-1 G.Aglieri Rinella N 30-4 M.Campbell (poster) N 16-108 19/10/2004 IEEE NSS 2004, Rome 11
SPD/PS HCal Calorimeters (1) Scintillating Pad Detector (SPD) and Preshower detector Located in front of calorimeters, 2 planes of scintillator pads separated by 1.5 cm thick lead converter Read-out: WLS and MaPMTs (64 channel) About 12000 tiles required, production in full swing ECal 19/10/2004 IEEE NSS 2004, Rome 12
Calorimeters (2) Electromagnetic calorimeter Shashlik type: 25 X 0 Lead/scintillator with WLS readout by PMT 3 regions with different cell size All 3300 modules produced Assembly to start beginning of 2005 σ E E (9.4±0.2)% E (0.83 ± 0.02)% ((145 ± 13) MeV)/E E GeV 19/10/2004 IEEE NSS 2004, Rome 13
Hadron calorimeter Calorimeters (3) Iron/scintillator of Tile type with 5.6 λ I, Read-out with WLS and PMTs 2 x 26 modules required, 90% produced Installation to start beg 2005 Energy resolution of production modules: 75%/ E 19/10/2004 IEEE NSS 2004, Rome 14
MWP chambers Muon System (1) GEM chambers 5 Stations with 1380 MWPCs Centre of first station: triple GEM Projective geometry Each station has 4 layers where 2 are logically OR ed (except first station: 2 layers) Read-out: wires, pads or mixed connected to form logical pads Talks at this conference: MWPC J.S.Graulich N 29-1 GEMs W. Bonivento N 1-4 P. De Simone N 39-5 Electronics: C.Deplano N 18-6 S.Caddedu (poster) N 33-14 19/10/2004 IEEE NSS 2004, Rome 15
Muon System (2) Multi Wire Proportional Chambers: Semi-automatic production tooling and testing equipment developed Wiring machine Construction of the 1380 MWP chambers (20 different types) has started in 5 centres, ~ 10% produced M3R1 Gain uniformity (M3R4) ±33% 19/10/2004 IEEE NSS 2004, Rome 16
Trigger Level-0 40 MHz Calorimeters, Muon system, Pile-up system P t of µ, e, h, γ 1 MHz Level-1 Level-0 information + Vertex Locator + Trigger Tracker 40 khz High Level Trigger Reconstruction of final states using full detector 200 Hz L0 Prototype Test bed Sub-farm 2005 Trigger challenge : Test the Real Time Framework and Trigger software in a realistic environment 19/10/2004 IEEE NSS 2004, Rome 17
Level-1 Traffic 1000 khz 5.5 GB/s DAQ Architecture Front-end Electronics FE FE FE FE FE FE FE FE FE FE FE FE TRM HLT Traffic 40 khz 1.6 GB/s TIER0 Switch Switch Switch Switch Switch Multiplexing Layer Readout Network L1-Decision Sorter Storage System 40 MB/s total SFC SFC SFC 7.1 GB/s 94 SFCs SFC SFC TFC System Switch Switch Switch Switch Switch Gb Ethernet Level-1 Traffic HLT Traffic Mixed Traffic ~1500 s Farm 19/10/2004 IEEE NSS 2004, Rome 18
Offline LHCb has a complete simulation, reconstruction and analysis chain in C++ Data challenge 2004 (production of events on distributed computing resources) was successfully completed: ~50 computing sites (DIRAC and LCG) ~470.years 210 M events produced Talks at this conference: G.Corti N 38-10 S.Easo N 44-6 G.Daquino N 44-8 19/10/2004 IEEE NSS 2004, Rome 19
Summary The LHCb experiment is a single-arm forward spectrometer that will allow precision studies of CP violating effects in the B meson system The construction of the detector is in progress and installation in the experimental area has started LHCb is expected to be ready for data taking in 2007 19/10/2004 IEEE NSS 2004, Rome 20