1

LHCb Central Tracker Upgrade

E. Thomas,on behalf of LHCb Collaboration

2013 IEEENSS/MIC/RTSD

Efficient trigger for many B decay topologies

Muon System

CALORIMETERSPRS + ECAL+ HCAL

RICH1

VERTEX LOCATOR

Efficient PID

Good decay time resolution

Magnet

Good tracking and mass resolution

RICH2

Trigger Tracker Inner and Outer Trackers

Beam 1

Beam 2

The LHCb detector at CERN

3

LHCb and LHC operation plans2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 …

1- 4 1032cm2s-1 2 1033cm2s-14 1032cm2s-1

LS1 LS2

3fb-1

0.9 – 7 TeV

5-7 fb-1 50 fb-1

13 – 14 TeV 13 – 14 TeV

50 ns 25 ns 25 ns

1 MHz 1 MHz 40 MHz

L∫L

Beam Energy

Bunch Spacing

L0 rate

After LS2,High occupancy in the central region requires new

detectors technology and granularitySilicon detectors with embedded r-o electronics must

be replaced

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The LHCb tracker UPGRADE

2 x ~3 m

2 x

~ 2.

5 m

readout

readout

Silicon strips

Straw Tubes Scintillating Fibers + SiPM

(An hybrid version combining Scintillating fibers and Straw Tube is also considered)

• 3 stations of X-U-V-X scintillating fibre planes (≤5°).=> 12 planes

• Every plane is made of 5 layers of Ø250 mm fibres, 2.5 m long.

• Symmetry around y=0• Read out by SiPM outside

acceptance• Minimize the dose to

read-out electronics and dead materials in the acceptance.

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Scintillating Fibers and SiPM

Npe

SiPM array

1 SiPM channel

Resolution (c.o.g.) 50-70 um

Double cladded scint. fibres, e.g. Kuraray SCSF-78, Ø 250 um

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Scintillating Fibers and SiPM already been used in HEP but: not for read out of 2.5m SciFi not in high radiation environment.

Main Challenges Radiation hardness of SiPM (increase of dark current with radiation) Radiation hardness of Fibers (decrease of light yield and attenuation length) LHC environment (25 ns), high occupancy and background Detector geometry and integration in existing experiment.

Main Challenges

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Radiation Profile: Fluka Simulation

Max dose to fibers 35 kGy (err 8%)Dose distribution strongly peaked around the beam pipe Dose to the SiPM: (6 1011 1MeV n eq)

-375 -300 -225 -150 -75 0 75 150 225 300 3751.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

total dose [Gy] @ at OT1 (central plane)

Y [cm]

FLUKA simulation for 50 fb-1 integrated luminosity

Gy/collision

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Fibers Radiation Tolerance

Irradiation performed at CERN and Karlruhe, up to ~60k Gy

Attenuation length decreases with absorbed dose

Logarithmic dependence (effect observed already at low dose)

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Mirror studies

C. Joram / CERN 9

R corr new Al.M. R corr new ESR R corr new TFC0

0.2

0.4

0.6

0.8

1

0.86

0.66

0.850.87

0.75

0.84

Plat

e 1

Plat

e 2

Refle

ctivi

ty

Aluminized mylar foil

3M ESR foil Aluminium thin film coating

Two samples of each type

Cheapest and technically simplest solution gives the best result.

Mirror

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Effect of radiations and mirror

Non-irradiated fibersIrradiated fibers (50 fb-1 eq.)

With Mirror

Without Mirror

Relative photon yield vs distance from SiPM

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SiPM Radiation Hardness studies

In UX85 – LHCb cavern: Cooled vs non cooled

SiPM

Radiation hardness studies and simulation have shown that SiPMshall be cooled down to ~-40C to operate smoothly over the entireLHCb upgrade (6 1011 1MeV n eq.)

Dark

Cur

rent

Time

Observation:Dark current increase with absorbed dose Possible annealing effect SiPM dark current is reduced by a factor ~2/8C

CFD simulation

SiPM arrays Scintillating FibersCooling pipe

Cooling SiPM to -40 C

Many configuration envisaged to optimize heat transfers

CFD Summary

Heat load dominated by incoming heat transfer (SiPM power < 2w/module)

Insulation thickness defined by dew point in LHCb cavern (<10-12C)

Heat load estimated to 5-10 Watt per module of 53 cm

SiPM cooling: mock-up testsThermal mock-up for 16 SiPM arrays

C3F8 2 phase cooling tests (in collab. with CTU Prague)

Also considering• 2-phase C2F6, blends• Single phase (Air, C6F14 ..)• CO2• Thermo electric

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R&D for fiber ribbon productionSe

mi-Man

ual tec

hnique

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LHCb Fiber ribbon assemblydevice being constructed at TU Dortmund – technique developped for PEBS at RWTH Aachen

R&D for fiber ribbon productionAuto

mated Te

chnique

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R&D for fiber ribbon productionAuto

mated Te

chnique

Winding wheel

Fiber supplyGroove to drive the fiber

OKPositioning precision <20 mm RMS

Not OKFaulty 4th layer

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SciFi modules 1-3

VELO telescope

SciFi Irradiated module 2

SiPM temperature control

TEST BEAM SPS OCT/NOV 2012

SciFi long module

GOALS • Test of irradiated vs non-irradiated

module (SiPM and Fibers)• Effect of temperature on SiPM noise.• Comparison KETEK vs Hamamatsu• Effect of mirror

Nov. 2012

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TEST BEAM resultsNov. 2012

Comparison of Hamamatsu and KETEK photon yieldWith mirror / without mirror at the far end

Mirror do improve the light yield from the far end Significant differences are observed between different manufacturer. Improvements expected from both manufacturers

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Readout electronicsThere is no adequate SiPM readout chip available

on the market Need to develop a new analog readout optimized

for 40MHz

Design choices depend on SiPM response, occupancy distributions, light propagation times

Options with part of the ASIC functionality transferred to FPGAs (more flexibility, cost?, radiation?) are also being studied

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The Fiber Tracker planning2013 2014 2015 2016 2017 2018 2019 2020

LS1 LS2

R&D

Demo-Modules

Detector components series production

Assembly ofStations

ToolingPre-module production

Assembly of modules

Dismantling of IT and OT detectors

Install Stations

Install ServicesPower, cooling,

shielding

Metrology and alignment

Commissioning

18 month