Summary: Mechanics - Overview of the MFT in ALICE. - Description of the MFT. - Description of a MFT detection plane. - Environment of the MFT. - Procedure

Summary:

Mechanics- Overview of the MFT in ALICE.- Description of the MFT.- Description of a MFT detection plane.- Environment of the MFT.- Procedure and tools for MFT installation.- Conclusion, discussion

Cooling- Thermal and fluidic studies on the MFT.- Preliminaries studies of the impact of cooling on the MFT barrel.

Next steps

MFT – WG7Mechanics and cooling

[email protected] ITS-MFT common week 10-13 March 2014

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mailto:[email protected]

The place of the MFT in ALICEcross section at the beginning of the project (11/2011)

beam

MFT

ITSabsorberBeam pipe

IP

TPC

V0, T0, FIT?

C side

A side

Disclaimer: the following presentation is mainly based on the MFT LoIwith some modifications: 6th plane added, planes position versus IP modified

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FITMFT barrel

Cage fixe

Beam pipeBeam pipe support

Service room

General view of the MFT in ALICESketch of integration MFT-ITS-FIT-BPrelease MFT – 11/2013Version TDR 6 ITS, BP od 19.8 mm MFT

AbsorberITS

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MFT cone

MFT disk

The dimensions of the beam pipe are crucial for us.They need to be fixed as soon as possible, od 19 mm will be better for MFT

MFT description. LoI release- 6 detection planes- 2 sealed half cone (up et down), (almost) symmetric

coneDetection plane

BP* gutter

*BP : Beam Pipe

BP support gutter

Front disk

Rear disk

Kapton sheet Room needed for the BP support

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Disk 0Disk 1Disk 2Disk 3Disk 4Disk 5

IP

768

569

688

531

493

455

Proposed distances between each disc and the IPIn accordance with ICD_20140207_MFT_vs_BP-1.ppt and related documents

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D 4

3.6

D 5

0.4

D 5

4.4

D 6

0.4

D 7

0

D 6

4

D 7

2

Diameter’s values are diameter of the beam pipe or bellow plus safety room of 4 mm given by CERN.

MFT’s detection plan description

Plan type 04

Beam pipe passage

Detection ladderAir cooling nozzle

Air inletAir outlet

Optical fiber6


Spilt view of the plan 04Objects constituting a plan

Front detection area

Rear detection area

Ladder support

pcb Optical transceivers

Air cooling nozzle

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Technical proposal for a diskPCB

Front detection area

Rear detection area

Ladder supportLadder support

ladders

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Here are the possible sizes of the various zones of every disks

Disc 0 to 3 Disc 4 and 5

20°

D1 D2

D3

PCB area

detection area

mm Disc 0 Disc 1 Disc 2 Disc 3 Disc 4 Disc 5

D1 380 400 420 440 520 560

D2 192 200 209 221 260 286

D3 49.6 49.6 49.6 60.4 70 78

D2 and D3 obtain according to the 3° and 9.4° angles, D1 defined according to ITS positionD3 values defined by adding a conservative safety room of 6 mm (2x3mm) for integration of the MFT’s ladders. (less than 2 mm expected).

preliminary

data

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MFT’s detection plane and ladder description

Listing of plane component and power consumption for a half MFT

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* 954 sensors @ 325 mW/ASIC => 310 W

* 75 GBT @ 2.5W/GBT => 190 W

* 52 W for optic transceiver

* 252 W for DC-DC converters

about 800 W for a half MFT

C. Renard and S. Bouvier, 19/02/2014

sensors

flex

Connector (PCB side)

Connector (flex side)stiffener

3 sensors ladder

MFT environment

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Beam Pipe

BP Support

fixe cage

C side BP support

« wing » of the BP support

Removables rails

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- Installation tools, « MFT down »

After the assembly of the MFT detector:MFT mounted on the MFT barrel

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MFT barrel

The half MFT complete is installed inside the MFT barrel.All the services will pass through the MFT barrel, with an exit on the C side.

A side

C side

Room for optical fiber

Zone de fixation FIT

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- Installation tools, « MFT down barrel »

Room for electrical and optical services

MFT fixing area

Passage air/water coolingInlet and outlet

Sketch of the MFT barrel

Fit fixing area

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- Procedure and tooling for MFT installation

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Insertion of the assembly (MFT, FIT, MFT barrel)The MFT and its barrel are mounted around the BP,then the assembly is translated along the BP (Y, YZ).

The MFT barrel will move along slider installed on the fixe cage.Fixation of the assembly will be made at the end of the sliding movement.

The same procedure will be made with the MFT “up”.

along Y

along YZ

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- Procedure and tooling for MFT installation

ITS, TPC, …

ITS outer and middle layers ITS inner layers

Rails extraction

Internal TPC cage

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- Conclusion et discussion

Area to be studied

Questions and interface discussions

Beam pipe dimension need to be fixedOd 19 mm? but also the other od and the BP support?

ITS TDR need to be fixed* Extremity close to MFT of the middle layer

* Room needed for MFT services

FIT* Mounted on the MFT barrel, ok* Fully independent from MFT, ok

but* Now updated dimensions needed

* Design of MFT barrel need information about FIT’s services

« middle et outer layers »Envelope (TDR6)

Modification proposalX

X

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- Cooling

Summary:

Mechanics- Overview of the MFT in ALICE.- Description of the MFT.- Description of a plan of the MFT.- Environment of the MFT.- Procedure and tooling for MFT installation.- Conclusion, discussion


- Next step

The estimated model is in accordance with that presented in the LoI (power, geometry), the power coming from the read out is not counted, the change of the geometry of the disk due to BP support and its “wing” is not taken into account.

Several estimated models, with various materials for the disk supports (TPG, Beryllium, composites), with various modes of cooling (conductive and convective).

Conclusion, first proposal Use of an airflow at room temperature to cool detection planes, on surface and inside the planes. - Simplify the design, simplifies constraints. - allows to limit the quantity of material used (lowering X0).

Proposal of the use of Beryllium for the planes material, good ratio rigidity, X0, thermal conductivity (LoI).Composite cabon/epoxy work also, less costly than Beryllium

Abstract of the MFT’s preliminary thermal studies

1,4 mm

2 mm

Full diskoutside

outside

inside3 distincts air flux

Air outlet

Air inlet

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Air 1 Air 2Air 3

Air 4 Air 5

Air 6

Beam pipe

Particules

Detection area

Example of simulation of air flow in the MFT

Air speeds inside the MFT are lower than 10 m/s

Average wall heat transfer are::

50 W/m².K outside the planes

30 W/m²K inside the planes

AIR5

AIR56

AIR6 Zoom INLET

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Simple geometry, goal was to test several material and kind of cooling.

ASIC

insulationflexsupport

ASIC:0,18µmLength 30 mm, width 8 mm(5 mm active, 3 mm passive)thickness 50µmpower deposit: 515 mW/sensor (LoI)Very conservative, actual value is: 325 mW/sensors

Flex: 2 x 57 µm aluminum

Insulation: 3 x 50µm de Kapton

Support/stiffener: 0,2 mm, Beryllium

convection

Water coolingPower deposit

convection

convection

Example of thermal simulation of a ASIC group

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Quarter plan description (LoI) :13 ladder1 ladder with 1 sensor1 ladder with 2 sensors6 ladders with 3 sensors5 ladders with 4 sensors

41 sensors for the studied quarter plan, about 328 sensors for the full disk (2 plans, recto and verso).

Power deposit on sensor is 515 mW. About 169 w for the full disk.Maximal air flow speed inferior at 10m/s.Wall heat transfer upside the sensors is 40 W/m².KWall heat transfer inside the plan is 25W/m².KAir flow temperature is 22°C

Calculated maximum temperature of the ASIC is about 30°C.

Thermal simulation on one MFT disk

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The use of the air at room temperature with a air flow speed lower than 10 m/s on the detection planes allows to obtain temperatures of functioning of the ASIC lower than 30 °C,

1/ first cost estimate (170 k€) concerning the manufacturing of support disk in Beryllium is too high, the use of composites Carbone-Epoxy should be favored. The Alloy AlBeMet could be an interesting candidate also (46 k€). Good to know that the use of one of these three materials cheek few on the results.

2/ assure the cooling of the complete MFT with only of a air flow is not a unique, definitive or settled solution; the final amount of total powers dissipated in the plans as well as other considerations (of geometry, mechanical design) will make that we can be brought to complete the air cooling by a liquid cooling, in the area located out of the zone of detection in particular.In addition, the front end electronic on the PCB will maybe need to be water cooled.

3/ The previous simulation have been made with sensor power consumption of 515mW/sensor, nowthe sensors power deposit last value is 325mW/sensor. This reduction of the power will allow to reduce the speed ofthe air flow, and/or suppress the air cooling inside plan (simplification of the mechanical design).

First conclusion

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Quick estimate of the amount of cooling water to put in the " MFT Barrel "

P = dm*Cp*DT

hypothesis:P = power = 1.6 kW/2 = 800 W = 0.8J/s dm = mass flow rate (kg/s) Cp = heat capacity= 4.2 kJ/kW*K DT = delta T= 3 °K 0.8 = dm*4.2*3 dm = 0.063 kg/s roughly 0.06litres/s = 0,06.10-3 m3

I’ll take a velocity of 1m/s in order to limit the pressure loss along the pipes.

0,06.10-3/1 = 0,6.10-4 m² make 60 mm², the cross section of 8.74 mm diameter pipe, round off at 9mm.

So we have a 9 mm inlet pipe and a 9 mm outlet pipe for each half MFT, that is to say two 9 mm diameter pipe per MFT barrel.

If we want smaller pipe we will multiplicate the number or pipe (pay attention to the pressure loss phenomena).So with a diameter of 3 mm we will have 18 pipes (9 inlet et 9 outlet). Etc…

Reminder!In these calculations all the power is evacuated by the water, in reality a big part will be evacuated by the air . So in reality we will need less pipes of water to achieve the cooling (2 or 3 time less).We will need to evaluat the « leakless » system (it will bring some limitation in the quality of the cooling).It's better to forbit the watercooling in the area of detection ( PCB area).If it is possible it will be necessary to plan some redundancy in the number of pipes.

Inlet pipe

Outlet pipe

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Summary:

Mechanics- Overview of the MFT in ALICE.- Description of the MFT.- Description of a plan of the MFT.- Environment of the MFT.- Procedure and tooling for MFT installation.- Conclusion, discussion


- Next steps



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Next steps (3 to 6 next months) MFT TDR preparation.

Cooling: - update of the thermal simulation, according to the up to date MFT power consumption and geometry.- new proposal, or confirmation and optimization of actual solution with read out Electronics and DC-DC converter taken into account- Design of a thermal test mockup.

Mechanics:- Optimization of the shape of the MFT cone (+ accessories) according to ITS TDR and discussion between ITS and MFT WG on mechanics.- Detailed mechanical design of a disk, then building of an integration mockup.- Participation at the WG5, stiffener design and supply,first carbon/epoxy stiffener available for the end of march).- Initiate work on MFT disk vibration (need more detailed mechanical design of the disk).- Service/ installation : updated and technical proposal for the MFT barrel.



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Documents

Summary: Mechanics - Overview of the MFT in ALICE. - Description of the MFT. - Description of a MFT detection plane. - Environment of the MFT. - Procedure