Forward detector overview

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


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


ALICE Si-FMD,T0,V0Integration in ALICE

Si-1Si-2

Si-3

V0-R

T0-R

12/03 2002


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


ALICE Si-FMD,T0,V0Si-FMD Overall Geometry

-5.1< <-1.7 3.4 < < 1.7

Si3 Si2Si1

12/03 2002


ALICE Si-FMD,T0,V0CERN Maquette 1:1

Si1 (inner)Si1(outer)

V0-R T0-R

Absorber

ITS-pixels

12/03 2002


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


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


ALICE Si-FMD,T0,V0Be, Al, or Inox beam pipe ?

Beam pipe

Flange

Std Al/Be pipe

* Primary signal

12/03 2002


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


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


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


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


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


ALICE Si-FMD,T0,V0Si inner ring design

Si

FEE

Hybrid

Support

Honeycomb

12/03 2002


ALICE Si-FMD,T0,V0Inner and outer Si rings

Si-FMD outer Si-FMD inner

12/03 2002


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


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


ALICE Si-FMD,T0,V0BRAHMS @ RHIC

Beam-Beam

Tiles and Si

12/03 2002


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


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


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


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


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


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


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


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


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


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


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


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


ALICE Si-FMD,T0,V0Extra’s

12/03 2002


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


ALICE Si-FMD,T0,V0FWD Detector layout

Si1Si3

Si2

V0-R

V0-L

T0-R

T0-L

12/03 2002


ALICE Si-FMD,T0,V0Centrality

determinationVertex distribution

1m

12/03 2002


ALICE Si-FMD,T0,V0Momentum dist. and

occupancies: B=0.2 and 0.4 T

12/03 2002


ALICE Si-FMD,T0,V0Origin of particlesB=0.2 and 0.4T

Forward detector overview

Documents

Transcript of Forward detector overview