Forward detector overview

1
Forward detector overview

• Si-FMD (Forward Multiplicity Detector) NBIINR
• Si-strip Ring counters (5) with gt50.000 channels
• -5.1lt ? lt -1.7 1.7lt ? lt 3.4
• Precise off-line charged particle multiplicity
  for AA, pp
• Fluctuations event-by-event, flow analysis
• T0 (Beam-Beam Detector) Jyvæskyla MEPhI, INR,
  Budker, Kurchatov
• 2 arrays of 12 Cerenkov radiators PM tubes
• -5lt ? lt -4.5 2.9lt ? lt 3.3
• Fast timing LVL0 signal (?50ps), online vertex
  determination
• Main time reference and backup for MinBias
  trigger
• V0 (Centrality and collision vertex) LyonMexico
• 2 arrays of plastic scintillator tiles w.
  fiberPMT
• -5.1lt ? lt -2.5 1.7lt ? lt 3.8
• Main LVL0 MinBias for pp and AA and centrality
  trigger AA
• Background rejection

2
Forward detectors
V0 1.7 lt h lt 3.8 and 5.1 lt h lt -2.5
Interaction trigger, centrality trigger and
beam-gas rejection. Two arrays of 72 scintillator
tiles readout via fibers
PMD pre-shower det.
T0L
T0R 2.9 lt h lt 3.3 T0 for the
TOF (lt 50 ps time res.) Two arrays of 12 quartz
counters. Also backup to V0
SI-FMD Multiplicity and dn/dh 1.7 lt h lt 3.4
and -5.1 lt h lt -1.7 Silicon pad detector disks
(slow readout)
3
Integration in ALICE
Si-1
V0-R
Si-2
T0-R
Si-3
4
FWD detectors
5
CERN Maquette 11
ITS-pixels
V0-R
T0-R
Si1 (inner)
Si1(outer)
Absorber
6
Si-FMD Overall Geometry
Si1
Si2
Si3

• -5.1lt ? lt-1.7
• 3.4 lt ? lt 1.7

7
Si rings manufactured of 6 wafers
Inner Rin4.2 cm Rout17.2 cm Outer Rin15.4
cm Rout28.4 cm
128
256
10x2x2565120 20x2x1285120
8
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 1.70lt ?lt2.29 In 2.01lt ?lt3.40
• Si2
• Out -2.29lt?lt-1.7 In -3.68lt ?lt-2.28
• Si3
• In -5.09lt ?lt-3.68
• Vertex shift (10cm) d? ? 0.1

?
9
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
May increase number of strips by factor of 2 or 3
using 128 ch VA-prime PA chip at same cost !
10
Multiplicity resolution
11
Hybrid with Viking PA chips
Connector(s) for power, control, read-out

• Hybrid cards contain
• FEPreampl. chips
• Bias voltages distribution
• Gate/strobe distribution
• Read-out clock distribution
• Detector bias connection

Other components
VA preampshaper 128 ch
Si detector
12
Front end electronics

• REQUIREMENTS
• Adapted for 5-25pF capacitance
• (300?m Si, 0.5 cm2 25pF, 1MIP 22.400 e-)
• Dynamic range 0-20 MIPS
• Radiation hardness gt200kRad
• 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

VA1 prime 2 (Viking-IDEAS) Input capacitance lt
30 pF 0-20 MIPs gt1MRad (0.35 ?m tech.) 1-3
?s 475 e- at 25 pF gt S/N 201 128 10 Mhz clock
1.3 mW/ch Test system available OK
13
FMD RO strategy
14
FMD FEE test setup
Labview DAQ
15
Si-FMD timetable (1)
A FRONT END (FE) READ OUT ELECTRONICS Completed
1 Demonstrate functionality of conceptual layout of FEE (Viking PA chip, control system, interface to ALTRO test board) April 1 2003
2 Final choice of VA pre-ampl. chip. RO test June 1, 2003
3 Test FEE system coupled to sample Si detector. Source and electron beam tests. June 1, 2003
4 Design, construction and test of prototype FMD digitizer card (FMDD), RO test with mini FMD-RCU October 1, 2003
5 Full Si detector element electronics chain RO with realistic RCU and DDL link to DAQ. June 1 , 2004
B MECHANICS AND INTEGRATION Completed
1 Full scale model manufactured (Si1) February 1, 2003
2 Cabling and Cooling issues resolved April 1, 2003
3 Full integration sequence decided June 1, 2003
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Si-FMD timetable (2)
C. SILICON DETECTOR Completed by
1 Complete market survey February 1, 2003
2 Define final specs March 1, 2003
3 Place order for prototype with industry April 1, 2003
4 Delivery Si-wafer prototype June 1, 2003
5 Start production of Si-hybrid FEE card June 1, 2003
6 Delivery prototype hybrid August 1, 2003
7 Si prototype test with FEE and BEE test RO setup December 1, 2003
8 Place final order for Si with industry April1, 2004
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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)

Absorber
V0-R
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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

Ring V0L V0L V0R V0R
Ring ?max/?min ?max/?min ?max/?min ?max/?min
1 -5.1/-4.6 -0.7/-1.2 3.8/3.4 2.6/3.8
2 -4.6/4.2 -1.2/-1.7 3.4/2.9 3.8/6.3
3 -4.2/-3.7 -1.7/-2.8 2.9/2.5 6.3/9.4
4 -3.7/-3.2 -2.8/-4.7 2.5/2.1 9.4/14.0
5 -3.2/-2.8 -4.7/-7.0 2.1/1.7 14.0/20.7
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V0 Ligth collection test

• For 1 MIP
• Setup A
• light yield 12 p.e. time resolution (?)
  1.6 ns
• Setup B
• Light yield 33 p.e. time resolution(?) 1.2
  ns

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V0 Triggering

• LVL 0 triggering with fast electronics (25 ns)
• Dynamic range 1- 300 MIPs
• 1 MIP efficiency gt 97
• Three trigger signals to the CTP corresponding to
  3 sum energy levels
• LowMB 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
• LR 79
• Eff. of Inelastic component 100
• HIJING in Pb-Pb at 5.5 ATeV (to be explored)

21
V0 Timetable

• Ongoing work
• Light optimization ? geometry of the
  counter/fiber elements with beam tests -gt end
  2002 (OK)
• Electronics specification ongoing,
• PM test and choice in Lyon
• Tests of full quadrant w. Beam
• -gt end 2003 (delayed from october
  2002)

• Construction in 2004/2005
• V0L by Mexico
• V0R by Lyon
• Electronics by Lyon
• Final system Commissionning
• ? middle 2005

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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 lt1.5 cm
• Beam-gas suppression
• Output Signals
• T0 (trtl)/2td
• T0v tr-tl
• T0-L, T0-R, Coinc
• Time and energies
• 3 levels of sum energy (low, medium, high)

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T0 Full scale model
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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
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T0 efficiency

• ALIROOT and Pythia simulations for MB pp
• 200 photon threshold applied
• Coinc. eff (LR) 83
• Left array ?71 and 87
• Right array ?78 and 94

T0-R T0-L
83
T0-R
T0-L
94
87
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T0 timetable

• RD of Cerenkov detector units
• -HV divider 2 prototypes ready,
• 3rd under const. (OK)
• -Quartz radiators waiting for
• final dimensions (no concern)
• RD of fast electronics unit
• -RD trigger generation unit (CAMAC
• prototype ready)
• -prototype I of CFD (failed, high
• cross-talk but problem solved)
• -prototype II of CFD (ready, very good
• test results)
• -prototype III of CFD (ready, very good
• test results)
• -prototype IV of CFD (DTD) (theo.stud.)
• -time meaner (2 options) (1 prototype ready)

• RD laser calibration system
• Market survey and purchase (manufacturer located
  but the purchase is delayed to assure the best
  configuration)
• Development of the calibration system (still
  in study)
• RD DAQ and trigger electronics
• Collaboration with TOF to guarantee the required
  performance (TOF is only sub-detector requiring
  high-precision off-line T0)
• Athens has expressed the wish to join. Funding
  situation should be clear within a few months.
• Mechanical construction
• 11 prototype ready
• TDR progressing as planned

Responsibilities Jyvæskylæ, MEPhI, INR, Budker,
Kurchatov.
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Summary

• FWD detectors baseline defined
• Physics role defined
• FWD detectors will supply basic day 1 physics
  (LVL0 trigger, global reaction information)
• Main detector parameters specified
• Concrete prototyping and industrial bids started
• Projects on track
• Aim at TDR by mid-2002
• Main open issues integration and installation
  procedures, materials budget (bgd), cooling, Back
  End Electronics and DAQ integration, analysis
  software

Si-FMD
V0
T0