Slide 1

ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk1 Forward detector overview Si-FMD (Forward Multiplicity Detector) NBI+INR oSi-strip Ring counters (5) with 25600 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) Jyvskyla + 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 Slide 2 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk2 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. Slide 3 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk3 Integration in ALICE Si-1 Si-2 Si-3 V0-R T0-R Slide 4 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk4 Si1 inner and outer 2 Rings Si 1 inner Si 1 outer 2 Rings Si 1 inner Si 1 outer T0 V0 Slide 5 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk5 Si-FMD Overall Geometry o-5.1< ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk17 Si-FMD (inner) sensors 256 strips 2 sectors VA-32 pre-amp. chip Connector Daisy chain 256 ch => 25 sec DT Slide 18 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk18 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 Slide 19 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk19 BRAHMS @ RHIC Beam-Beam Tiles and Si Slide 20 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk20 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 =5600 50% over p+p oLHC ( s=5800 AGeV): -9 < < 9 BRAHMS @ RHIC 200 Subm. PRL dec 2001 pppp Slide 21 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk21 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. 00112001 Slide 22 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk22 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 Slide 23 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk23 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 max / min /R min /R max max / min / 143/69 -5.1/- 4.6/0.47 40/603.8/3.4/0.42 269/110 -4.6/- 4.2/0.47 60/923.4/2.9/0.42 3110/174 -4.2/- 3.7/0.46 92/1412.9/2.5/0.42 4174/276 -3.7/- 3.2/0.46 141/2162.5/2.1/0.42 5276/445 -3.2/- 2.8/0.47 216/3362.1/1.7/0.42 Slide 24 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk24 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 Slide 25 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk25 V0 Triggering LVL 0 triggering with fast electronics (25 ns) Dynamic range: 1- 300 MIPs 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) Slide 26 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk26 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 Slide 27 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk27 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 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk33 Forward Detectors Role in Trigger Physics and rates oCentral Pb+Pb : Nch(Si) 15.000-20.000 op+p Nch(Si) 50-100 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 ( 0.1-0.2 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 Slide 34 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk34 FWD Detector layout Si1 Si3 Si2 V0-R V0-L T0-R T0-L Slide 35 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk35 Centrality determination Vertex distribution 1m Slide 36 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk36 Momentum dist. and occupancies: B=0.2 and 0.4 T Slide 37 ALICE Si-FMD,T0,V0 12/03 2002Jens Jrgen Gaardhje, NBI, gardhoje@nbi.dk37 Origin of particles B=0.2 and 0.4T