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Forward detector overview

Forward detector overview. Si-FMD (Forward Multiplicity Detector) NBI+INR Si-strip Ring counters (5) with 25600 channels -5.1<  < -1.7; 1.7<  < 3.4 Precise off-line charged particle multiplicity for A+A, p+p Fluctuations event-by-event, flow analysis

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Forward detector overview

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  1. Forward detector overview Si-FMD (Forward Multiplicity Detector) NBI+INR • Si-strip Ring counters (5) with 25600 channels • -5.1<  < -1.7; 1.7<  < 3.4 • Precise off-line charged particle multiplicity for A+A, p+p • Fluctuations event-by-event, flow analysis T0 (Beam-Beam Detector) Jyvæskyla + MEPhI, INR, Budker, Kurchatov • 2 arrays of 12 Cerenkov radiators + PM tubes • -5<  < -4.5; 2.9<  < 3.3 • Fast timing LVL0 signal (=50ps), online vertex determination • Main time reference and backup for MinBias trigger V0 (Centrality and collsion vertex) Lyon+Mexico • 2 arrays of plastic scintillator tiles w. fiber+PMT • -5.1<  < -2.5; 1.7<  < 3.8 • Main LVL0 MinBias for p+p and A+A and centrality trigger A+A • Background rejection Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  2. Forward detectors V01.7 < |h| < 3.8and –5.1 < | h | < -2.5 Interaction trigger, centrality trigger and beam-gas rejection. Two arrays of 72 scintillator tiles readout via fibers PMD pre-shower det. T0L T0R2.9 < |h| < 3.3 T0 for the TOF (< 50 ps time res.) Two arrays of 12 quartz counters. Also backup to V0 SI-FMD Multiplicity and dn/dh 1.7 < h < 3.4 and -5.1 < h < -1.7 Silicon pad detector disks (slow readout) Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  3. Integration in ALICE Si-1 V0-R Si-2 T0-R Si-3 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  4. Si1 inner and outer V0 Si 1 outer Si 1 outer 2 Rings 2 Rings Si 1 inner Si 1 inner T0 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  5. Si-FMD Overall Geometry Si1 Si2 Si3 • -5.1<  <-1.7 • 3.4 <  < 1.7 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  6. CERN Maquette 1:1 ITS-pixels V0-R T0-R Si1(outer) Si1 (inner) Absorber Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  7. Si rings manufactured of 6” wafers Inner: Rin=4.2 cm Rout=17.2 cm Outer: Rin=15.4 cm Rout=28.4 cm 128 256 10x2x256=5120 20x2x128=5120 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  8. Coverage in pseudorapidity Design criteria: Largest possible  coverage Largest symmetry left and right Overlap between systems Constraints: Vacuum tube outer envelope: 42 mm, Outer radius, ITS, Absorber, cables Background from secondaries(small angles) Si1: Out: 1.70< <2.29In: 2.01< <3.40 Si2: Out: -2.29<<-1.7 In: -3.68< <-2.28 Si3: In: -5.09< <-3.68 Vertex shift (10cm): |d|  0.1  Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  9. Be, Al, or Inox beam pipe ? * Primary signal Flange Std Al/Be pipe Beam pipe Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  10. Background: secondariesDensity / cm2 => Main background is due to ITS+ services and vaccuum chamber +supports Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  11. Ring geometry and segmentation Design Criteria: Keep modest occupancy for central Pb+Pb Number of azimuthal and radial sectors matched to physics (<0.1, <2/20, fluctuations and ellipt. flow) Strip areas matched to Front-end electronics Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  12. Charged particle occupancy including secondaries 20  sectors 256 strips each 5120 channels 40  sectors 128 strips each 5120 channels 20  sectors 256 strips each 5120 channels Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  13. Multiplicity resolution RMS=6% For 1 full sector. Same for =0.1 ring Central Pb+Pb: multiplicity resolution better than 5% from analog signal p+p: occupancy <0.01/strip => counting mode Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  14. Front end electronics REQUIREMENTS: Adapted for 5-25pF capacitance (300m Si, 0.5 cm2: 25pF, 1MIP: 22.400 e-) Dynamic range: 0-50 MIPS Radiation hardness: >200kRad Peaking time: 1-2 s Low noise (good S/N) High integration Sample/hold and serial read-out, 10 MHz clock Moderate power consumption Simple slow controls and power reg. Affordable cost VA32 _RICH (IDEAS): Input capacitance: 10-30 pF 0-40 MIPs >1MRad (0.8 m tech.) 1-3 s 475 e- at 25 pF 32 (or higher) 10 Mhz clock 1.3 mW/ch Test system available OK Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  15. Si inner ring design Si FEE Hybrid Support Honeycomb Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  16. Inner and outer Si rings Si-FMD outer Si-FMD inner Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  17. Si-FMD (inner) sensors VA-32 pre-amp. chip 256 strips 2  sectors Connector Daisy chain 256 ch => 25 sec DT Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  18. Si-FMD Timetable Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  19. BRAHMS @ RHIC Beam-Beam Tiles and Si Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  20. pp RHIC vs. LHC • RHIC (s=130 AGeV): -5 << 5 Plateau: –2 << 2 (40% of range) dN/d(=0)=550. (s=200 AGeV): -6 << 6 dN/d(=0)=625. Nch =5600 50% over p+p • LHC (s=5800 AGeV): -9 << 9 BRAHMS @ RHIC 200 Subm. PRLdec 2001 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  21. SPS Limiting particle prod. in fragmentation region BRAHMS: RHIC 200.Subm. PRL Nucl-ex. 00112001 • RHIC: saturation of particle production in fragmentation region is already achieved at SPS. • Width of Frag. Region is   3. • LHC:  = (–9,+9) • RHIC200:  = (–6,+6). •  May expect that central region at LHC extends to –(6,+6). •  Si-FMD and V0 detectors cover (-5.1,+1.7), i.e. most of the interesting region. BRAHMS. Phys Lett. B523 (2001) 227 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  22. V0 detector • Two segmented scintillator hodoscopes on either side of IP • Minimum bias trigger:p-p and Pb-Pb • Main on-line LVL0 centrality trigger:Pb-Pb • Background filter for the dimuon spectrometer • Two arm for beam-gas rejection • Luminositycontrol • Multiplicity measurement (high occupancy) Absorber V0-R Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  23. V0 Segmentation • V0-L and V0-R: 5 rings each • Rings 1-4: 30° sectors (12) • Ring 5: 15° sectors (24) • Rings 1-3 are in the dimuon arm acceptance Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  24. V0 scintillator element • Plastic Scintillator • Wave Lenght Shifting fibers in groove • Clear optical fibers for light transport (25 m) • Photomultiplier • Present tests in lab. and in beam: Optimization of the light in PM • Time resolution measurement approx. 1 ns expected Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  25. V0 Triggering • LVL 0 triggering with fast electronics (25 ns) • Dynamic range: 1- 300 MIP’s • 1 MIP efficiency > 97% • Three trigger signals to the CTP corresponding to 3 sum energy levels: Low:MB for pp and Pb-Pb (low) High: central and Medium: semi-central Pb- Pb Simulations: AliRoot w/ PYTHIA 6.15 in pp at 7 TeV L and R single efficiencies: 85% L*R : 79% Eff. of Inelastic component: 100% HIJING in Pb-Pb at 5.5 ATeV (to be explored) Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  26. V0 Timetable • Constructionin 2004/2005 V0L by Mexico V0R by Lyon Electronics by Lyon • Final system Commissionning → middle 2005 • Ongoing work • Light optimization → geometry of the counter/fiber elements • PM test and choice • Electronics specification • System baseline design to be decided by June 2002(ALICE note) • Electronics developpement in Lyon and in-beam tests → end 2003 • Tests of sector(s) → end of 2003 • Response to multi-particles • Test in real situation (LHC clock) with final electronics Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  27. T0 Beam-Beam counter • Precise event timing (=50ps) • Start detector for ALICE-TOF • Main LVL0 event trigger • Pre-trigger for TRD • Rough on-line vertex determination <1.5 cm • Beam-gas suppression • Output Signals: • T0 = (tr+tl)/2+td • T0v = tr-tl • T0-L, T0-R, Coinc • Time and energies • 3 levels of sum energy (low, medium, high) Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  28. T0 elements and beam test • PM tubes: fine mesh • Hamamatsu R3432-01 (26 mm Ø) or FEU-187 (30 mm Ø) • 30 mm thick radiator (Lucite) • Time resolution with broad 1.28GeV/c pion beam measured to 55ps. • Set threshold at 200 photons • (1 MIP gives 600 Photons) Photons in T0-R Photons in T0-L Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  29. T0 efficiency • ALIROOT and Pythia simulations for MB p+p • 200 photon threshold applied • Coinc. eff (L*R) = 83% • Left array: =71 and 87 % • Right array: =78 and 94 % T0-R * T0-L 83% T0-R T0-L 94% 87% Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  30. T0 timetable • 2002 ongoing • CFD development, dynamic range 1:500 • Time meaner, TDC • PM Tests with pulsed laser in magn. field. • CERN beam tests • Trigger scheme and electronics • Early 2003: Protoype w. mech. Mounting • 2004: Construct full system • Ready in 2005 Responsibilities: Jyvæskylæ, MEPhI, INR, Budker, Kurchatov. Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  31. Summary • FWD detectors baseline defined • Physics role defined • FWD detectors will supply basic day 1 physics (LVL0 trigger, global reaction information) • Moving into concrete prototyping phase, industrial bids • Projects on track • Main open issues: integration and installation procedures, materials budget (bgd), Back End Electronics and DAQ integration, analysis software Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  32. Extra’s Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  33. Physics and rates Central Pb+Pb : Nch(Si) 15.000-20.000 p+p Nch(Si) 50-100 Pb+Pb 8kHz. (1kHz central) Average event spacing >100s p+p up to 1 coll/bunch crossing Average event spacing 25 ns WHO does it? LVL0 Timing: T0 Vertex ( 1-2 cm) T0 Vertex ( 0.1-0.2 cm) TPC Rough on-line Centrality cut on dE V0 p+p trigger V0 Timing+vertex(p+p) T0,V0 Precise centrality Si Fluctuations Si Azimuthal distribution Si Off-Line PID (dE) Si Level 0 T0,V0 Off-line, Higher level Si Forward Detectors Role in Trigger Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  34. FWD Detector layout V0-R T0-L V0-L T0-R Si3 Si1 Si2 Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  35. Centrality determinationVertex distribution 1m Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  36. Momentum dist. and occupancies: B=0.2 and 0.4 T Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

  37. Origin of particlesB=0.2 and 0.4T Jens Jørgen Gaardhøje, NBI, gardhoje@nbi.dk

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