12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 1
ALICE Si-FMD,T0,V0Forward detector overview
Si-FMD (Forward Multiplicity Detector) NBI+INRo Si-strip Ring counters (5) with 25600 channels o -5.1< < -1.7; 1.7< < 3.4o Precise off-line charged particle multiplicity for A+A, p+p o Fluctuations event-by-event, flow analysis
T0 (Beam-Beam Detector) Jyvæskyla + MEPhI, INR, Budker, Kurchatov
o 2 arrays of 12 Cerenkov radiators + PM tubeso -5< < -4.5; 2.9< < 3.3o Fast timing LVL0 signal (=50ps), online vertex determinationo Main time reference and backup for MinBias trigger
V0 (Centrality and collsion vertex) Lyon+Mexicoo 2 arrays of plastic scintillator tiles w. fiber+PMTo -5.1< < -2.5; 1.7< < 3.8o Main LVL0 MinBias for p+p and A+A and centrality trigger A+Ao Background rejection
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 2
ALICE Si-FMD,T0,V0Forward detectors
T0R 2.9 < || < 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/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
T0L
PMD pre-shower det.
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 3
ALICE Si-FMD,T0,V0Integration in ALICE
Si-1Si-2
Si-3
V0-R
T0-R
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 4
ALICE Si-FMD,T0,V0Si1 inner and outer
2 Rings
Si 1 inner
Si 1 outer2 Rings
Si 1 inner
Si 1 outer
T0
V0
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 5
ALICE Si-FMD,T0,V0Si-FMD Overall Geometry
-5.1< <-1.7 3.4 < < 1.7
Si3 Si2Si1
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 6
ALICE Si-FMD,T0,V0CERN Maquette 1:1
Si1 (inner)Si1(outer)
V0-R T0-R
Absorber
ITS-pixels
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 7
ALICE Si-FMD,T0,V0Si 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=5120
20x2x128=5120
128
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 8
ALICE Si-FMD,T0,V0Coverage 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 9
ALICE Si-FMD,T0,V0Be, Al, or Inox beam pipe ?
Beam pipe
Flange
Std Al/Be pipe
* Primary signal
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 10
ALICE Si-FMD,T0,V0Background: secondariesDensity / cm2
Radius(cm)
Primary
Ch.Part.
TotalCh. part
Primary
/total
Pipe Pipe/total
ITS ITS/total
T0 Abs
Si1 inner
5 26.7 42.7 0.62 14.5 0.34 1.1 0.02 0.1 0.3
10 8.2 11.9 0.69 1.9 0.16 1.8 0.15 0.1 0.3
15 3.5 7.6 0.44 0.8 0.10 2.8 0.37 0.1 0.3
Si1 outer
15 2.8 5.8 0.48 0.8 0.13 1.8 0.31 0.0 0.3
20 2.0 4.4 0.46 0.5 0.10 1.5 0.35 0.0 0.1
25 1.5 2.7 0.53 0.3 0.11 0.7 0.26 0.0 0.1
28 1.2 2.4 0.52 0.2 0.10 0.7 0.28 0.0 0.1
Si 3
5 13.3 58.2 0.22 44.0 0.75 0.6 0.01 0.2 0.0
10 5.2 20.6 0.25 14.3 0.69 0.8 0.04 0.1 0.0
15 2.8 10.3 0.27 6.8 0.65 0.6 0.05 0.1 0.0
=> Main background is due to ITS+ services and vaccuum chamber +supports
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 11
ALICE Si-FMD,T0,V0Ring 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
4.2 17.2 7-50 20 256 0.07-0.27
1.9-3.5 7-14
Si 1 outer
15.4
28.4 2.4-5.8 40 128 0.25-0.45
1.1-1.5 14-20
Si2 inner
4.2 17.2 6-40 20 256 0.07-0.27
1.6-2.8 7-14
Si 2 outer
15.4
28.4 2.4-5.8 40 128 0.25-0.45
1.1-1.5 14-20
Si 3 inner
4.2 17.2 10-60 20 256 0.07-0.27
2.7-4.2 7-14
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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 12
ALICE Si-FMD,T0,V0Charged 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 13
ALICE Si-FMD,T0,V0Multiplicity resolution
Central Pb+Pb: multiplicity resolution better than 5% from analog signal
p+p: occupancy <0.01/strip => counting mode
RMS=6%
For 1 full sector. Same for =0.1 ring
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 14
ALICE Si-FMD,T0,V0Front end electronics
REQUIREMENTS: Adapted for 5-25pF
capacitance(300m Si, 0.5 cm2: 25pF,
1MIP: 22.400 e-)Dynamic range: 0-50 MIPSRadiation hardness:
>200kRadPeaking time: 1-2 sLow noise (good S/N)High integrationSample/hold and serial read-
out, 10 MHz clockModerate power consumptionSimple 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 s475 e- at 25 pF32 (or higher)10 Mhz clock
1.3 mW/chTest system available
OK
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 15
ALICE Si-FMD,T0,V0Si inner ring design
Si
FEE
Hybrid
Support
Honeycomb
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 16
ALICE Si-FMD,T0,V0Inner and outer Si rings
Si-FMD outer Si-FMD inner
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 17
ALICE Si-FMD,T0,V0Si-FMD (inner) sensors
256 strips
2 sectors
VA-32 pre-amp. chip
Connector
Daisy chain 256 ch => 25 sec DT
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 18
ALICE Si-FMD,T0,V0Si-FMD Timetable
Item Estimated completion date Status
Overall system design March 2002 Baseline and envelopes defined
Choice of FE electronics June 2002 Basic choices made
Procure test wafers August 2002
Procure test FE electronics October 2002
Design Back end (BE) electronics
June 2003
Mech. Design and integration
December 2002
Assembly test detector March 2003
Test with sources/e-beam/BRAHMS at RHIC
December 2003
Final Design January 2004
Procure full Si and electronics
January 2004
Manufacture mechanics June 2004
Delivery Si and FEE June 2004
Assembly full system December 2004
Test full system March 2005
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 19
ALICE Si-FMD,T0,V0BRAHMS @ RHIC
Beam-Beam
Tiles and Si
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 20
ALICE Si-FMD,T0,V0RHIC 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. PRL dec 2001
pp
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 21
ALICE Si-FMD,T0,V0Limiting particle
prod. in fragmentation region
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
SPS
BRAHMS: RHIC 200. Subm. PRL Nucl-ex. 00112001
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 22
ALICE Si-FMD,T0,V0V0 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 23
ALICE Si-FMD,T0,V0V0 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 V0R
Rmin/Rmax ηmax/ηmin/Δη Rmin/Rmax ηmax/ηmin/Δη
1 43/69-5.1/-
4.6/0.47 40/60
3.8/3.4/0.42
2 69/110-4.6/-
4.2/0.4760/92
3.4/2.9/0.42
3 110/174-4.2/-
3.7/0.4692/141
2.9/2.5/0.42
4 174/276-3.7/-
3.2/0.46141/216
2.5/2.1/0.42
5 276/445-3.2/-
2.8/0.47216/336
2.1/1.7/0.42
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 24
ALICE Si-FMD,T0,V0V0 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 25
ALICE Si-FMD,T0,V0V0 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 TeVL and R single efficiencies: 85%L*R : 79%Eff. of Inelastic component: 100%HIJING in Pb-Pb at 5.5 ATeV (to be explored)
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 26
ALICE Si-FMD,T0,V0V0 Timetable
Construction in 2004/2005V0L by MexicoV0R by LyonElectronics 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 27
ALICE Si-FMD,T0,V0T0 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)
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 28
ALICE Si-FMD,T0,V0T0 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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 29
ALICE Si-FMD,T0,V0T0 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
T0-R T0-L
94% 87%
83%
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 30
ALICE Si-FMD,T0,V0T0 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.
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 31
ALICE Si-FMD,T0,V0Summary
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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 33
ALICE Si-FMD,T0,V0Forward Detectors Role in Trigger
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 >100s
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
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 34
ALICE Si-FMD,T0,V0FWD Detector layout
Si1Si3
Si2
V0-R
V0-L
T0-R
T0-L
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 35
ALICE Si-FMD,T0,V0Centrality
determinationVertex distribution
1m
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 36
ALICE Si-FMD,T0,V0Momentum dist. and
occupancies: B=0.2 and 0.4 T
12/03 2002
Jens Jørgen Gaardhøje, NBI, [email protected] 37
ALICE Si-FMD,T0,V0Origin of particlesB=0.2 and 0.4T