1 jan conrad (cern) psd liverpool, sept. 2005 jan.conrad @cern.ch (cern) beam test performance and...

Jan Conrad (CERN)1

PSD Liverpool, Sept. 2005Jan.Conrad @cern.ch (CERN)

Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector

INFN and Università Bari, Comenius Univ. Bratislava,INFN and Università Catania, CERN Geneva, Institute of Experimental Physics, Kosice, INFN Laboratori Nazionali Legnaro (LNL), INFN and Università Padova, INFN and Università Salerno, INFN and Università Udine

J. Conrad (CERN)

On behalf of the SPD project in the ALICE Collaboration

12.09.2005

Jan Conrad (CERN)2


Content• Introduction:

- ALICE@LHC Inner Tracking System (ITS) Silicon Pixel Detector (SPD)

• Beam tests at CERN SPS- 2002+2003 (SPD)

- 2004 (ITS)

• Simulation of the Silicon Pixel Detector

• Conclusions

Prime goal: validation of electronics

Spin off : efficiencies, intrinsic precisions

Integration: detectors used to test DAQ/triggers etc…

Jan Conrad (CERN)3


The ALICE experiment @ LHC

• ALICE is dedicated to Heavy Ion Physics

- PbPb @ 5.5 TeV

- cope with high multiplicity (up to 8000 /unit rapidity) high granularity

- measure large range in pt

low magnetic field B < 0.5 T low material budget

• Initially interesting p-p physics

ITS

Jan Conrad (CERN)4


Silicon Pixel Detectors (SPD)

Silicon Drift Detectors (SDD)

Silicon Strip Detectors (SSD))

44 c

m44

cm

39 cm

39 cm

24 cm24 cm

15 cm15 cm

7.6 cm7.6 cm3.9 cm3.9 cm

SSDSSD

SDDSDD

SPDSPD

The Inner Tracking System

- 6 barrel layers

- 2 Silicon Pixel (hybrid), 2 Silicon Drift (true 2 dimensional r/o )

- 2 double sided Silicon Strips

- in total 12.5 Million sensitive cells (75 % SPD)

- material budget reduced to minimum

- |η| < 0.9

- 220 krad, 3 x 1012 (1 MeV n)/cm2 , 10 years integrated (SPD layer)

The ITS in numbers:-primary vertexing to better than 100 m -secondary vertices: (ex. D0 K- π+)-low momentum tracking (p < 100 MeV) -high pT tracking improvement-minimum bias trigger in

pp mode (SPD)

The ITS Physics Tasks

SPD: digital r/o

SDD/SSD: analog r/o

Jan Conrad (CERN)5


1 ladder1 ladder

R/O (MCM)

R/O (MCM)

INFN Pad

ova

INFN Pad

ova

5 ALICE1 5 ALICE1

RO ChipsRO Chips

Si sensorSi sensor

193 mm long

193 mm long

ALICE1ALICE1readout chipreadout chip

P. R

iedl

erP

. Rie

dler

Pixelr φ: 50 μz:425 μ

The (hybrid) Silicon Pixel Detector

half-stave

half-stave

200 μ- 2 barrel layers,

- 240 silicon sensors 5 r/o-chips/sensor (a “ladder”),

- 9.83 million pixels, (32x256 = 8192)/chip

- 2 ladders and r/o = half stave

- 8 inch wavers, bumped, thinned down to 150 µ

-Alu-Polyimide Pixel Bus

The SPD in numbers

Jan Conrad (CERN)6


Beam Tests: 2002 and 20032002 CERN SPS : 350 GeV p/π, 200 and 300 µ sensors tested

2003 CERN SPS : 120 GeV p/π , 158 GeV/A Indium ions on target, 300 µ sensors tested

~ 70 cm

~ 100 cm

Omitted:

- set ups with ladder assemblies

- ion-on-target setups

- plane with complete read-out chain (2003)

,next slide

Schematics of Proton Setup 2002

Schematics of Proton Setup 2003No magnetic field !

Jan Conrad (CERN)7


2002/2003 Setups

Complete Readout chain2003

2002

Jan Conrad (CERN)8


Beam Tests Results 2002/2003: Overview• Beam Test 2002

- Online: - read-out of multi-chip configuration tested

- Offline:- Efficiency: > 99 % at working point.- Spatial precision (rφ) at working point:

σ = (11.1 ± 0.2) µm

• Beam Test 2003- Online:

- full read-out chain (prototypes) tested- read-out tested in higher multiplicity environment

- Offline: - efficiencies and spatial precision of 300 µ sensor - In-on-Pb target runs analysis under way (Pulvirenti et. al., Pixel 2005).

Jan Conrad (CERN)9


2002/2003 results: intrinsic precision

• Use 4 planes as reference planes to define tracks residual distribution

• Residual Distribution = Tracking error folded with intrinsic precision of the device tested.

• Tracking error ?- Multiple scattering- Intrinsic precision of tracking device

(but tracking device ≈ test device ?)

Iterative Method

?

Precision as function of angle,cluster size: not shown

Residual distributions 2003:

large pix dim small pix dim

6000 e 3000 e

Point of operation

Jan Conrad (CERN)10


Beam Test: 2004

120 GeV p/π beam

w/o target

SPD SDD SSD

2 full half staves

P. R

iedl

erP

. Rie

dler

Jan Conrad (CERN)11


Beam Test 2004

SSD brains

SDD brains ?

SPD brains

High Tec cooling system

SPD r/o electronics and

trigger rack

Jan Conrad (CERN)12


Beam Test Results 2004• Online

- First test of: - ALICE Trigger with > 1 subsystem - ALICE DAQ with > 1 subsystem - SPD: full read-out with final components

• Offline- Software framework AliRoot for data analysis used for hardware debugging during beam test.

- Initial results obtained using standard tools within AliRoot (so far only applied to simulated data !)

- Results used to validate use of FLUKA in the ALICE detector simulation

Beam Test 2002/2003:

Learning about the detector

Beam Test 2004:

Learning using the detector F.

Care

na

F.

Care

na

Jan Conrad (CERN)13


SPD simulation

2002 data

Simulation

Cluster Sizes :

Cluster Types :

INFNINFN BariBari

• Based on GEANT3• Charge sharing: Gaussian diffusion, charge cloud

spread out during the particle’s traversal: σdiff dsensor / √Vbias ≈ 5 – 15 μm

• tuning of model parameters under way

Jan Conrad (CERN)14


Conclusions

• Beam Tests of the SPD in CERN in 2002 and 2003- successfully tested the read-out system of the SPD- detector efficiency and intrinsic detector precision determined as

function of relevant parameters

• Beam Tests of the ITS at CERN SPS in 2004- SPD halfstaves used as tool- ALICE DAQ/Trigger system successfully used for >1 subdetector of

ALICE for the first time- beam test used to validate use of ALICE software framework AliRoot

for data analysis and simulation

• Simulation of the Silicon Pixel Detector- simulation based on GEANT3, including charge sharing by diffusion

qualitatively reproduces beam test data- model parameters currently being tuned using beam test data of

2002 and 2003- use of other particle tracking packages (FLUKA) validated using beam

test data/simulation

MORE DETAILS IN PROCEEDINGS !

Jan Conrad (CERN)15


BACK-UP SLIDES

Jan Conrad (CERN)16


SPD Multilayer Bus

• wire bonds to the readout chips and MCM

• provides data -, control- and power-lines between readout chips and MCM

AluminumPolyimideGlue

12

34

56

READOUT CHIP

PIXEL DETECTOR

12

56

COOLING TUBE

11mm2mm

7 77 7SMD component

240µm

200µm

150µm

Jan Conrad (CERN)17


Tasks of the Inner Tracking System

-primary vertexing to better than 100 primary vertexing to better than 100 m m -secondary vertices: (ex. -secondary vertices: (ex. D0 K- π+)-low momentum tracking (p < 100 MeV) -low momentum tracking (p < 100 MeV) -high pT tracking improvement-high pT tracking improvement-minimum bias trigger in pp mode (SPD)-minimum bias trigger in pp mode (SPD)

p/p

(%

)

10

30

50

ITS

SPD

no ITS

with ITS

PbPb D0 π- π+

Jan Conrad (CERN)18


Setup 2002: more detailed view

Jan Conrad (CERN)19


Setup 2003

ScintillatorsScintillators

4mm Pb target4mm Pb target

Minibus 0 (two readout chips)Minibus 0 (two readout chips)

Minibus 1 (two readout chips)Minibus 1 (two readout chips)P

lane

0P

lane

0P

lane

1P

lane

1

270270291291

615615

1038103810601060

12741274

Middle plane (single readout chip)Middle plane (single readout chip)

Jan Conrad (CERN)20


2002/2003 results: detector efficiency1)

1) Only cluster within < 10

σ(residual) are considered

The Detector efficiency

The detector is fully efficient (> 99%) above a threshold setting of DAC 150 (~ 4000 e).

Operational Point:

DAC 200!!

Threshold (e)

INFN

INFN

Bari

Bari

Jan Conrad (CERN)21


Intrinsic Precision: GEANT simulation and data

INFN

INFN

Bari

Bari

Jan Conrad (CERN)22


Results 2002/2003: Intrinsic Precision

1px . 2px .

smaller threshold

larger threshold

Short pixel dimension

1,2 px clusters in test plane

INFN

INFN

Bari

Bari

Threshold (DAC 200 ≈ 3000 e)

Point of operation

Typical track angle in HI coll (2nd layer)

Jan Conrad (CERN)23


Diffusion and no diffusion

INFN

INFN

Bari

Bari

INFNINFN BariBari

Jan Conrad (CERN)24


Simulation GEANT/FLUKA/DATA

Jan Conrad (CERN)25


Multi Chip Module

Clock/Trig

Pixel Chip 1 Pixel Chip 10

AnalogPILOT

Digital PILOTGOLSerializer

OpticalModule

Ref. levels

Analog Multiplicity

Fast-OR

JTAG/Ck

Data Data out

JTAG

Pixel Bus MCM

FADC

Thermal sensors

. . . . .

…Data

JTAG/Ck

Jan Conrad (CERN)26


TID Fluence 1MeV n eq. [cm-2] @ 10 years

ATLAS Pixels 50 Mrad 1.5 x 1015

ATLAS Strips 7.9 Mrad 2 x 1014

CMS Pixels ~24Mrad ~6 x 1014 *CMS Strips 7.5Mrad 1.6 x 1014

ALICE Pixel 220krad 3 x 1012

LHCb VELO - 1.3 x 1014/year**

*Set as limit, inner layer reaches this value after ~2 years **inner part of detector (inhomogeneous irradiation )

Radiation LevelsRadiation Levels

P. RiedlerP. Riedler

1 jan conrad (cern) psd liverpool, sept. 2005 jan.conrad @cern.ch (cern) beam test performance and...

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