ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Forward detector overview Si-FMD (Forward Multiplicity Detector) NBI+INR oSi-strip Ring counters (5) with channels o-5.1<  < -1.7; 1.7<  < 3.4 oPrecise off-line charged particle multiplicity for A+A, p+p oFluctuations event-by-event, flow analysis T0 (Beam-Beam Detector) Jyvæskyla + MEPhI, INR, Budker, Kurchatov o2 arrays of 12 Cerenkov radiators + PM tubes o-5<  < -4.5; 2.9<  < 3.3 oFast timing LVL0 signal (  =50ps), online vertex determination oMain time reference and backup for MinBias trigger V0 (Centrality and collsion vertex) Lyon+Mexico o2 arrays of plastic scintillator tiles w. fiber+PMT o-5.1<  < -2.5; 1.7<  < 3.8 oMain LVL0 MinBias for p+p and A+A and centrality trigger A+A oBackground rejection

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Forward detectors T0 R 2.9 < |  | < 3.3 T 0 for the TOF (< 50 ps time res.) Two arrays of 12 quartz counters. Also backup to V0 SI-FMD Multiplicity and dn/d  1.7 <  < 3.4 and -5.1 <  < -1.7 Silicon pad detector disks (slow readout) V0 1.7 < |  < 3.8 and –5.1 < |  | < -2.5 Interaction trigger, centrality trigger and beam- gas rejection. Two arrays of 72 scintillator tiles readout via fibers T0 L PMD pre-shower det.

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Integration in ALICE Si-1 Si-2 Si-3 V0-R T0-R

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si1 inner and outer 2 Rings Si 1 inner Si 1 outer 2 Rings Si 1 inner Si 1 outer T0 V0

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si-FMD Overall Geometry o-5.1<  <-1.7 o 3.4 <  < 1.7 Si3 Si2 Si1

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, CERN Maquette 1:1 Si1 (inner)Si1(outer) V0-R T0-R Absorber ITS-pixels

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si rings manufactured of 6” wafers 256 Inner: Rin=4.2 cm Rout=17.2 cm Outer: Rin=15.4 cm Rout=28.4 cm 10x2x256= x2x128=

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Coverage in pseudorapidity Constraints: Vacuum tube outer envelope: 42 mm, Outer radius, ITS, Absorber, cables Background from secondaries(small angles) Design criteria: Largest possible  coverage Largest symmetry left and right Overlap between systems Si1: Out: 1.70<  <2.29 In: 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 

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Be, Al, or Inox beam pipe ? Beam pipe Flange Std Al/Be pipe * Primary signal

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Background: secondaries Density / cm 2 Radius (cm) Primary Ch.Part. Total Ch. part Primary /total Pipe /total ITS /total T0Abs Si1 inner Si1 outer Si => Main background is due to ITS+ services and vaccuum chamber +supports

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Ring geometry and segmentation Rin (cm) Rout (cm) Particle density (cm -2 ) Phi sectors Radial sectors Strip area (cm -2 ) Average occupancy Strip capacitance (pF) Si1 inner Si 1 outer Si2 inner Si 2 outer Si 3 inner 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

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Charged particle occupancy including secondaries 20  sectors 256 strips each 5120 channels 20  sectors 256 strips each 5120 channels 40  sectors 128 strips each 5120 channels

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Multiplicity resolution Central Pb+Pb: multiplicity resolution better than 5% from analog signal p+p: occupancy counting mode RMS=6% For 1 full sector. Same for  =0.1 ring

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Front end electronics REQUIREMENTS: Adapted for 5-25pF capacitance (300  m Si, 0.5 cm2: 25pF, 1MIP: 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: 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

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si inner ring design Si FEE Hybrid Support Honeycomb

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Inner and outer Si rings Si-FMD outerSi-FMD inner

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si-FMD (inner) sensors 256 strips 2  sectors VA-32 pre-amp. chip Connector Daisy chain 256 ch => 25  sec DT

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Si-FMD Timetable ItemEstimated completion dateStatus Overall system designMarch 2002Baseline and envelopes defined Choice of FE electronicsJune 2002Basic choices made Procure test wafersAugust 2002 Procure test FE electronicsOctober 2002 Design Back end (BE) electronicsJune 2003 Mech. Design and integrationDecember 2002 Assembly test detectorMarch 2003 Test with sources/e- beam/BRAHMS at RHIC December 2003 Final DesignJanuary 2004 Procure full Si and electronicsJanuary 2004 Manufacture mechanicsJune 2004 Delivery Si and FEEJune 2004 Assembly full systemDecember 2004 Test full systemMarch 2005

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, RHIC Beam-Beam Tiles and Si

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, RHIC vs. LHC oRHIC (  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 = % over p+p oLHC (  s=5800 AGeV): -9 <  < 9 RHIC 200 Subm. PRL dec 2001 pppp

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Limiting particle prod. in fragmentation region oRHIC: saturation of particle production in fragmentation region is already achieved at SPS. o  Width of Frag. Region is   3. oLHC:  = (–9,+9) oRHIC200:  = (–6,+6). o  May expect that central region at LHC extends to – (6,+6). o  Si-FMD and V0 detectors cover (-5.1,+1.7), i.e. most of the interesting region. BRAHMS. Phys Lett. B523 (2001) 227 SPS BRAHMS: RHIC 200. Subm. PRL Nucl-ex

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, 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 Luminosity control Multiplicity measurement (high occupancy) V0-R Absorber

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, 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 Rin g V0LV0R R min /R max η max /η min /ΔηR min /R max η max /η min /Δη 143/ /- 4.6/ /603.8/3.4/ / /- 4.2/ /923.4/2.9/ / /- 3.7/ /1412.9/2.5/ / /- 3.2/ /2162.5/2.1/ / /- 2.8/ /3362.1/1.7/0.42

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, V0 scintillator element oPlastic Scintillator oWave Lenght Shifting fibers in groove oClear optical fibers for light transport (25 m) oPhotomultiplier oPresent tests in lab. and in beam: Optimization of the light in PM  Time resolution measurement approx. 1 ns expected

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, V0 Triggering  LVL 0 triggering with fast electronics (25 ns)  Dynamic range: 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)

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, V0 Timetable  Construction in 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

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, T0 Beam-Beam counter oPrecise event timing (  =50ps) oStart detector for ALICE- TOF oMain LVL0 event trigger oPre-trigger for TRD oRough on-line vertex determination <1.5 cm oBeam-gas suppression oOutput Signals: oT0 = (t r +t l )/2+t d oT0v = t r -t l oT0-L, T0-R, Coinc oTime and energies o3 levels of sum energy (low, medium, high)

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, T0 elements and beam test oPM tubes: fine mesh oHamamatsu R (26 mm Ø) or FEU-187 (30 mm Ø) o30 mm thick radiator (Lucite) oTime resolution with broad 1.28GeV/c pion beam measured to 55ps. oSet threshold at 200 photons o(1 MIP gives 600 Photons) Photons in T0-R Photons in T0-L

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, T0 efficiency oALIROOT and Pythia simulations for MB p+p o200 photon threshold applied oCoinc. eff (L*R) = 83% oLeft array:  =71 and 87 % oRight array:  =78 and 94 % T0-R * T0-L T0-RT0-L 94% 87% 83%

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, T0 timetable o2002 ongoing oCFD development, dynamic range 1:500 oTime meaner, TDC oPM Tests with pulsed laser in magn. field. oCERN beam tests oTrigger scheme and electronics oEarly 2003: Protoype w. mech. Mounting o2004: Construct full system oReady in 2005 Responsibilities: Jyvæskylæ, MEPhI, INR, Budker, Kurchatov.

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Summary oFWD detectors baseline defined oPhysics role defined oFWD detectors will supply basic day 1 physics (LVL0 trigger, global reaction information) oMoving into concrete prototyping phase, industrial bids oProjects on track oMain open issues: integration and installation procedures, materials budget (bgd), Back End Electronics and DAQ integration, analysis software

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Extra’s

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Forward Detectors Role in Trigger Physics and rates oCentral Pb+Pb : Nch(Si) op+p Nch(Si) oPb+Pb 8kHz. (1kHz central) oAverage event spacing >100  s op+p up to 1 coll/bunch crossing oAverage event spacing 25 ns WHO does it? oLVL0 Timing: T0 oVertex (  1-2 cm) T0 oVertex (  cm) TPC oRough on-line Centrality cut on dE V0 op+p trigger V0 oTiming+vertex(p+p) T0,V0 oPrecise centrality Si oFluctuations Si oAzimuthal distribution Si oOff-Line PID (dE) Si oLevel 0 T0,V0 oOff-line, Higher level Si

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, FWD Detector layout Si1 Si3 Si2 V0-R V0-L T0-R T0-L

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Centrality determination Vertex distribution 1m

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Momentum dist. and occupancies: B=0.2 and 0.4 T

ALICE Si-FMD,T0,V0 12/ Jens Jørgen Gaardhøje, NBI, Origin of particles B=0.2 and 0.4T