considerations on integration, mechanics and cooling r. santoro, d. perini its upgrade plenary...

Considerations on integration, mechanics and cooling

R. Santoro, D. PeriniITS Upgrade plenary meeting, 29-May 2011

ITS upgrade plenary meeting 2

Outlook ITS integration before the upgrade Upgrade requirement Upgrade conceptual design Basic ideas on cooling and thermal coupling structures

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ALICE DetectorInner Tracking System (ITS) Three different silicon detector technologies, two

layers each Pixels (SPD), Drift (SDD), double side Strips (SSD)

Side C

SSD

SDD

SPDParameter Pixels Drifts Strips radius (inner plane) cm 3.9 15.0 38.0 radius (outer plane) cm 7.6 23.9 43.0 length ±z (inner layer) cm 14.1 22.2 43.1 length ±z (outer layer) cm 14.1 29.7 48.9 cell size (r z) µm2 50 425 202 294 95 40000 spatial precision (r) µm 12 35 20 spatial precision (z) µm 100 25 830 max. occupancy (Pb-Pb central) % 2.1 2.5 4 max. expected dose (10 years) Gy 2,7x103 2,5x102 5x101 total area m2 0.21 1.3 5 total no. of channels 9.8 M 133 k 2.6 M material budget (both layers) % X0 2.28 2.39 1.69

SSD

SDD

SPD

Side A


Silicon Pixel Detector (SPD)

2 layers of silicon pixel detector grouped in 2 half barrels to be mounted face to face around the beam pipe

Half-barrelOuter surface

Half-barrelInner surface

Half-barreland services

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SPD positioning

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Beryllium Beam pipe

1st half-barrel

SPD Internal mean radius 3.9 cmBeam pipe radius 3 cm

1st half-barrelin place

2nd half-barrelin place


Positioning of the rest of ITS and TPCSDD+SSD moved over the SPD to form the ITS

SDD + SSDSPD fully connected

on side C

ITS fully connected on side C

TPC

TPC moved over the ITS

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ITS: side view

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Absorber

Forward Detectors

Drift and StripSilicon detectors

Side A Side C

Silicon Pixel Detectors and

mechanical structure

Beam Pipe


ITS upgrade under discussion Main requirements

Low material budget (less than 0.5% X/X0) First layer as closer as possible to the interaction point to improve the impact parameter

Radius of the new beam pipe will be 20mm Fast insertion / extraction of the inner layers: winter shut down (less than 10 weeks)

Services routed only on side A. The absorber blocks the access on the other side New tracker in the forward region: end caps between ITS and absorber

Conical beam pipe is requested to reduce the material budget for tracks at high η Operating at room temperature

First scenario under study: insertion of 1 extra layer of pixel detector Reduced effort, but incompatible with the conical beam pipe

Second scenario under study: 3 new layers of silicon pixel detectors Compatible with the conical beam pipe and the Muon Forward Tracker (MFT) Further improvement wrt the 1st scenario in terms of impact parameter

Third scenario under study: 7 new layers of silicon detectors 3 (or 4) layers of pixels 4 (or 3) layers of strip End cups on both sides

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AbsorberDrift and StripSilicon detectors

Side A Side C

Beam Pipe

Space for the new pixel detector

ITS: side view

AbsorberDrift and StripSilicon detectors

Side A Side C

Beam Pipe

ITS: side view Space for the conical beam pipe

and the Muon Forward

Tracker

ITS upgrade plenary meeting 11R. Santoro

Requirements for the Scenario 2 3 insertable new pixel layers + SDD + SSD and space for MFT

Beam pipe 20 mm

Drift constrain 100 mm

Number of staves (#S) / layer Free

Mean sensors radial position (3 layers) 23mm (1st), 47mm (2nd), 90mm (3th)

Detector area (rphy x z) 15 x free mm2

Dead area (rphy) 2.5 mm (hybrid option)2 x 2.5 mm in opposite sides (MALICE option)

Stave length (z) if |η| = 1 and σz=7.94cm 220mm (1st), 270mm (2nd), 365mm (3th)

Power consumption As low as possible: reasonable range 0.25 - 0.5 W/cm2

Services2 x #S flat cables for the power (200 mu thick?)1 x #S optical links (1 or 2 fibers per optical link) 2 x #S cooling tubes (not needed in case of air cooling)

Total material budget (X/X0) per layer As low as possible: upper limit 0.5 %

Hybrid option material budget contribution

Total = 0.5%- Detector (sensor = 100 um + FEE = 50 um) = 0.16 %- Bus (half of the actual bus or even better) < 0.24 % - Mechanics/cooling = 0.1 % (200µm carbon fiber equivalent)

Monolithic option material budget contribution

Total = 0.39 %- Detector (50 um) = 0.055 %- Bus (half of the actual bus or even better) < 0.24 % - Mechanics/cooling = 0.1 % (200µm carbon fiber equivalent)


New pixel detector: first conceptual design 3 layers of SI-pixel sensors: 1st layer at 23 mm from the IP Full structure divided in 2 half, to be mounted around the beam pipe and to be moved

along the beam pipe towards the final position Modules fixed to the 2 carbon fiber wheels All the services on side A

Carbon Fiber skin

3 Si-pixelLayers

Carbon fiber support wheel

Cooling tubes

Options under discussion rφ ermeticity Cooling:

Water, CO2 and fluorocarbons Single and double phase

Thermal coupling structures Carbon foam (used in this draw) Polyimide micro-channel Silicon micro-channel


Muon Forward Tracker

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Side C

Conical beam pipe

Free space for the MFT

Requirements 6 planes of pixel detectors between the ITS and the muon absorber (MFT)

3°- 9° of acceptance with respect to the beam line (range @ -3η) Conical beam pipe is required to reduce the beam pipe material budget at these angles

Under study Mechanical integration Feasibility of such a beam pipe Coexistence of Barrel (|η| < 1) and

forward acceptance


Carbon Foam: Conceptual design

Inspired on ATLAS and PANDA design

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Single module Side view

Carbon fiber support skin

Carbon foam

Inlet / outlet Cooling tube

Volume indicating sensor + electrical bus

Suitable for all the coolant options: water, CO2 and fluorocarbons Suitable for single and double phases cooling Studies are needed to select the material and to optimize thickness / geometry for the optimal

rigidity

Layout details Carbon fiber skin 200µm thick (x/x0 ≈ 0.1%) Carbon foam

1st layer: 500µm thick in the central part (x/x0 ≈ 0.07%)

2nd and 3rd layers: 900µm thick in the central part (x/x0 ≈ 0.125%)

Peek tube: Øext 1.2mm / Øint 1mm (x/x0 ≈ 0.12 %)

Estimated material budget: 1st layer

Central part (≈0.17 %) Along the tubes (≈0.26 % + liquid)

2nd and 3rd layers: Central part (x/x0 ≈ 0.225%) Along the tubes (≈0.275 % + liquid)


Polyimide micro-channel

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Pyralux® LF7001 (Kapton®) 24µm

Pyralux® PC 1020 (polyimide) 200µm

Pyralux® LF110 (Kapton®) 50µm

Material budget considerations with single phases cooling Water or C6F14

Fabrication process Starting point: sheet 50 µm of LF110 lamination 200 µm of Photo imageable coverlay

4 layers of PC1020 Creation of the grooves by photolithography process @ 180°C glue by hot pressing the sheet 24 µm LF7001 on top of the

structure Cure all the object @ 180°C for 10 Hours.


Polyimide Micro-channel Layout optimization

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Analytic evaluation with simplified geometry (inlet and outlet in opposite sides) to optimize the micro-channel dimension


CFD analysis: water

R. Santoro Outlet section channelInlet section channel Middle section channel

Axonometric view single

channel

L = 20 cm

W= 1.6 cm

T water in 15°C

T water out 18°C

INOUT

16.65 °C

20.62 °CT water in

15°C

T water out 18°C

Upper surface

N° 16 channels800 X 200 µm


The prototype with the optimized geometry has been delivered House made connectors for test purpose have been produced Characterization tests are on the way:

Geometrical measurements Ducts area: CNC Machine (Mitutoyo) surface roughness: NTEGRA platform (atomic force microscope)

Mechanical test Leak test Mechanical resistance Strain –stress behavior

Thermo fluid dynamic test Cooling performance Vs fluid dynamic at working condition

Polyimide micro-channel: on-going activities

Si-Micro-channel: Conceptual design Micro-channels made on silicon plates by etching and covered with Si-plate by fusion bonding

no CTE mismatch and high pressure resistance Two layouts are under discussion

Distributed micro-channels: material budget equally distributed below the sensitive area Sideline micro-channels: micro-channels confined at the chip’s border, where there is the major power

consumption (first prototype in July)

Distributed micro-channels

x/x0 < 0.16%x/x0 = 0.05% (no liquid inside)x/x0 = 0.08% (C4F10)

Further considerations Suitable with double-phases cooling (C02 or fluorocarbons)

Simulation and R&D are needed Limitation: the length of the wafer is presently <= 100 mm Layout optimization and services to be studied

Sideline micro-channels

hole

%X0 = 0 in the sensitive area !!

Common Inlet pipe

Module n

Module n+1

Common return pipe


Summary

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The ITS upgrade requirements has been discussed Main focus was on the 2nd scenario: 3 new layers of pixel detectors with the possibility to allocate

a conical beam pipe

A first mechanics conceptual design was shown Big effort in the integration is now needed

Material budget of the order of 0.1% for mechanical support and cooling is the goal at least for the first layer

The different options concerning cooling and thermal coupling were discussed Carbon foam: simulation and material procurement for tests are needed Polyimide micro-channel: simulation is progressing well and the prototype has been delivered.

The tests are on the way Silicon micro-channel: discussions on prototype design is started


Spare

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1st layer

2nd layer

1,5

x/x0

Skin 0,1

Foam 0,300 0,042

Tube 0,12

Total 0,262

1,6

x/x0

Skin 0,1

Foam 0,400 0,056

Tube 0,12

Total 0,276


CFD analysis: C6F14

R. Santoro Outlet section channelInlet section channel Middle section channel

Axonometric view single

channelINOUT

17.16 °C

26.01 °CT C6F14 in

15°C

Upper surface

T C6F14 out 18°C

L = 20 cm

W= 1.6 cm

T water in 15°C

T water out 18°C

N° 16 channels800 X 200 µm

Power consumption0.5 W/cm2

Outlet section channel

Results CFD analysis [H2O vs C6F14]

Cosimo Pastore & Irene Sgura ( Politecnico di Bari & INFN Bari) 20-04-2011 16

Assonometric view single

channel

Outlet section channel

H2O C6F14

INOUT

CONSIDERATIONSA) @ height channel 200 mm the thermo-fluid dynamic H2O behavior IS MORE EFFICIENT then C6F14.

B) WATER doesn’t allow (very difficult) to reduce the height of the channel minor then 200 mm due to the pressure drops (no leak- less mode)


μ-channels in NA62

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Channels 100 µm deep

Manifolds 280 µm deep

Interface to the connector

First prototypes tested successfully!

IN

OUT

flow

Pictures taken from NA62 GTK WG meeting presentation - P. Petagna

NA62 requirements:• Acceptable DT over sensing area ~ 5 °C• Dimensions of sensing area: ~ 60 x 40 mm

• Max heat dissipation: ~ 2 W/cm2 • Target T on Si sensor ~ -10 °C

Forward spectrometer – conceptual design

• Conceptual design– Highly segmented calorimeter at

small angles• Electromagnetic front section

– Sandwich silicon-tungsten– 30 longitudinal layers– Sensitive layers:

MAPS technology, e.g. MIMOSA/ULTIMATE (20mm x 20mm)

• Hadron section– Sandwich tungsten/iron-scintillator– 60 longitudinal layers– Sensitive layers:

scintillators (3cm x 3cm) read out by Multi-Pixel Avalanche Photodiodes (ala PSD @ NA61)

– Rebuilt (wide gap) and relocated compensator magnet

– Low mass beam pipe– Silicon pixel tracker close to the IP

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considerations on integration, mechanics and cooling r. santoro, d. perini its upgrade plenary...

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