Geometry baseline of the new Inner Tracking System, ALICE Chinorat Kobdaj

Geometry baseline of the new Inner

Tracking System, ALICE

Chinorat KobdajSuranaree University of

Technology, ThailandOn behalf of the ALICE

CollaborationAug 8, 2013

APCTP 2013 LHC Physics Workshop @ Korea, August 6-8, 2013, Konkuk Univeristy, Seoul, South Korea

The ALICE Detector

The Current ALICE Detector2


Introduction to the Inner Tracking System upgrade

ALICE ITS (present detector)

ALICE ITS

Current ITS 6 concentric barrels, 3 different technologies• 2 layers of silicon pixel (SPD)• 2 layers of silicon drift (SDD)• 2 layers of silicon strips (SSD)

The Current ALICE Inner Tracking System

3

ALICE ITS

ALICE ITS


LoI and ITS CDR endorsed by LHCC in Sep 2012

APCTP 2013 LHC Physics Workshop @ Korea, August 6-8, 2013, Konkuk Univeristy, Seoul, South Korea 4

2013 Selection of Technology

2014 Final Design

2015-2016 Construction / Test detector modules

ALICE ITS Upgrade

2017-2018 Assembly / Installation

2019-2020 Test run / Full run

2021 Comple

te

5

LongShutdown

1

EvaluationTechnology

Construction and Installation

Time Line

R &D

2012 2013 2014 2015 2016 2017 2018

Today

2019 2020 2021 2022

ConceptualDesign Report

Prototype

TechnicalDesign Report

FinalDesign

andValidation

Pb-Pbat

√sNN= 5.1 TeV

Pb-Pbat

√sNN = 5.5 TeV

LongShutdown

2Production/Construction

and Test of Detector

modulesPre-commissioning

and Assembly

LongShutdown

3Complete

Ar-Arhigh

luminosity run

p-Pbat

full energy

Run

Pb-Pb

Selectionof

Technologies Installation in the cavern

Full deployment of

DAQ/HLT


New ITS Design goals

1. Improve impact parameter resolution by a factor of ~3• Get closer to IP (position of first

layer): 39mm 22mm • Reduce material budget: X/X0

/layer: ~1.14% ~ 0.3% (for inner layers)• Reduce pixel size

ocurrently 50mm x 425mmmonolithic pixels O(20mm x 20mm), hybrid pixels state-of-the-art O(50mm x 50mm)

7APCTP 2013 LHC Physics Workshop @ Korea, August 6-8, 2013, Konkuk Univeristy, Seoul, South Korea


2. Improve tracking efficiency and pT resolution at low pT

• Increase granularity: 6 layers 7 layers , reduce pixel size

• Increase radial extension: 39-430 mm 22– 430 (500) mm

3. Fast readout• readout of Pb-Pb interactions

at > 50 kHz and pp interactions at ~ several MHz

4. Fast insertion/removal for yearly maintenance• possibility to replace non

functioning detector modules during yearly shutdown

Upgrade optionsTwo design options have being studied A.7 layers of pixel

detectors (baseline)B.3 inner layers of pixel

detectors and 4 outer layers of strip detectors

7 layers of pixels

Option A

3 layers of pixels

4 layers of strips

Option B

Pixels: O(20x20µm2 – 50 x 50µm2) Pixels: O( 20x20µm2

– 50 x 50µm2)Strips: 95 µm x 2 cm, double sided 9


New ITS (baseline)Inner Barrel: 3 layersOuter Barrel: 4 layersDetector module (Stave) consists of - Carbon fiber mechanical support- Cooling unit- Polyimide printed circuit board- Silicon chips (CMOS sensors)


Inner Barrel Layers • 3 innermost layers at

r= 22, 28 and 36 mm• Same z-length: 27 cm• Assumed chip size: 15

mm x 30 mm >> 9 chips/module

• X/X0≤ 0.3%Modules Chips

Layer 1 12 108Layer 2 16 144Layer 3 20 180Total 48 432


11

Middle and Outer Barrel Layers• 4 outermost layers at

r= 48, 52, 96 and 102 mm• 84 cm < z-length <

150 cm• Double chip rows per

module• X/X0≤ 0.8%

Modules

Chips

Layer 4

48 2688

Layer 5

52 2912

Layer 6

96 9600

Layer 7

102 10200

Total 298 25400


2

Project Coordination(PL, DPL, SPL, TC, RC,

Upgrade Tasks Coordinators)

Institute Board

(PL, DPL, SPL, TC, Team Leaders)

3. Pixel chip design4. Sensor Post Processing and Mass test

5. Characterization and Qualification6. Inner Layers Module7. Middle Layers Module8. Outer Layers Module

10.Readout Electronics

2. Detector Simulation and Reconstruction1. Physics Performance

PROJECT ORGANIZATION

ITS Operation(RC, PL, DPL, SPL, TC, QAC, CC,

experts)9. Mechanics and Cooling

UPG

RAD

E


14

OrganizationParticipating Institutes• CERN• China (Wuhan)• Czech Republic

(Prague)• France IN2P3-

CNRS (Strasbourg)• Italy INFN (Bari,

Bologna, Cagliari, Catania, Frascati, Legnaro, Padova, Roma, Torino, Trieste)

• Korea (Inha, Pusan, Yonsei)

• Netherlands (Nikhef and Utrecht)


• Pakistan (COMSATS)• Russia (St.

Petersburg)• Slovakia (Kosice

IEP)• Thailand (Nakhon

Ratchasima SUT)• UK STFC

(Daresbury, RAL), Univ. of Birmingham

• Ukraine (Kharkov, Kiev)

• USA (Berkeley)

15

Upgraded beampipe - studies

C- side Al section

A-side Al section

Central Be part


16

The upgraded beampipe, drawing v4.0


17

Effect of Al-extension on A sideBackground visible in Central Barrel detectors

a) Entries in (x,y) plane

b) Entries vs Radius

Extract only the secondary vertices physics events to see only the contribution from the new beampipe

PIPE

New ITS

PhysicsBackground


MC with the beampipe

MC without the beampipe

A-side Al section

C- side Al section


18

19

Secondary vertices versus z direction

Effect of Al-extension on A sideBackground visible in Central Barrel detectors

MC settings: HiJing central PbPb, interaction diamond: 6 cmSecondary particles further out (>20cm) are clearly negligible ...

Effect ofAl-part

(|z|>40cm)is negligible

< 1 per eventAPCTP 2013 LHC Physics Workshop @ Korea, August 6-8,

2013, Konkuk Univeristy, Seoul, South Korea

20

Studies: Impact of materials in forward direction

Compares number of gamma conversion between Al and Be extension on the A-side


21

Results of the beampipe studies

● No impact of Al-extension in terms of background in the Central Detectors

● 80 cm is sufficient for the central part (Be) of the new beam-pipe (no significant background is observed from the Al part further away).

● Forward direction, difference between Al/Be clearly visible, up to 60% of gammas converted at eta~5.5

● Impact of Al-extension on the physics case to be answered by the Forward-Calorimeter teamAPCTP 2013 LHC Physics Workshop @ Korea, August 6-8,

2013, Konkuk Univeristy, Seoul, South Korea

Model 0 in the CDRwith cooling pipes at the

vertices


22

Stave modeling and material budgets

Model 0 in Aliroot of the 1st layer

a = 23 degreeAPCTP 2013 LHC Physics Workshop @ Korea, August 6-8,

2013, Konkuk Univeristy, Seoul, South Korea23

Model 0 material budgetcooling pipe outer radius of 1.5 mm

Model 1 in the CDRwith polyimide microchannel

cooling


24

Model 1 in Aliroot of the 1st layer

a = 57 degreeAPCTP 2013 LHC Physics Workshop @ Korea, August 6-8,

2013, Konkuk Univeristy, Seoul, South Korea25

Model 1 material budget

Model 2 in the CDR with pipe cooling in the

middle


26

Model 2.1 in AliRoot of the 1st layer

a = 57 degree


27

Model 2.1 Material budget with Cooling pipe outer radius =1.5 mm

Model 2.2 in Aliroot of the 1st layer

a = 57 degree


28

Model 2.2 Material budget with cooling pipe outer radius =1.0 mm


Model 3 in the CDR with silicon microchannel cooling

Model 3 in Aliroot


30

Model 3 Material budget

Material Budgets of different models

CDR(no

overlaps)

Aliroot with overlaps

Model 0

0.26% 0.324%

Model 1

0.30% 0.357%

Model 2.12.2

0.31%

-

0.378%0.282%

Model 3

- 0.257% 31APCTP 2013 LHC Physics Workshop @ Korea, August 6-8, 2013, Konkuk Univeristy, Seoul, South Korea

The Flip-chip Mounting

Consider the interconnection between ASIC and the module PCB


CHIP 1

CHIP 2

CHIP 3

CHIP 4CHIP 5

CHIP 6

CHIP 7

CHIP 8

CHIP 9

33


Mounting to the stave

PCB design – inner layer modulesContact pads distributed

over chip surface:

Aliroot Model in TGeo

CHIP 1CHIP 2

CHIP 3CHIP 4

CHIP 5CHIP 6

CHIP 7CHIP 8CHIP 9


Results of the flip-chip mounting • Radius of solder balls does not affect the total material budget much (0.002%) • The thickness of the flex cable contributes significantly to the total material budget

Our studies confirm the material budget for inner layers : X/X0 /layer ~ 0.3%

Conclusion


Documents

Geometry baseline of the new Inner Tracking System, ALICE Chinorat Kobdaj