ATLAS Detector : status and upgrade plans

ATLA

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ATLAS Detector: status and upgrade

plans

P. Morettini - ATLAS Collaboration

3/9/2013 1Paolo Morettini - ICNFP 2013

ATLA

SOutlineIn this talk, we will briefly review the performance of the ATLAS detector in its present configuration and we will illustrate the upgrade plan: ATLAS performance 2010-2012 Motivations for the upgrade Phase 0 upgrade – LS1 i.e. now Phase 1 upgrade – LS2 – 2018-2019 Phase 2 upgrade – LS3 – 2022-2023

An obvious disclaimer: experience teaches us that many things can change in ten years, so, especially for Phase 2, there are many unknowns (from the scientific and also from the financial point of view) that can modify our plans.

3/9/2013Paolo Morettini - ICNFP 2013 2

ATLA

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Muon spectrometer m tracking

• MDT (Monitored drift tubes)

• CSC (Cathode Strip Chambers)

• RPC (Resistive Plate Chamber) Trigger

• TGC (Thin Gas Chamber) Trigger

• Toroid Magnet

3 Level Trigger system

• L1 – hardware – 100 kHz 2.5 ms latency

• L2 – software – 3-4 kHz 10 ms latency

• EF – software – 100 Hz 1-2 s latency

Inner Detector (ID)Tracking

• Silicon Pixels 50 x 400 mm2

• Silicon Strips (SCT) 80 mm stereo

• Transition Radiation Tracker (TRT) up to 36 points/track

• 2T Solenoid Magnet

Calorimeter systemEM and Hadronic energy

• Liquid Ar (LAr) EM barrel and end-cap

• LAr Hadronic end-cap• Tile calorimeter (Fe –

scintillator) hadronic barrel

The ATLAS Detector

4/7/2012 3Paolo Morettini - iWoRID 2012

Tile Calorimeter Liquid Argon calorimeter

TRT Pixel Detector SCTSolenoid Magnet

Muon Detector

Toroid Magnet

ATLAS Performance

ATLA

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Paolo Morettini 46/5/2013

ATLAS Trigger and DAQ108 channels on-detector

(40 MHz readout)

L2 trigger – 10 kHz – 20 msOn L1 selected geometrical regions. Software.

L1 trigger – 100 kHz – 25 usThen extraction from detector to readout system

Event Filter – 400 Hz – 2 sSoftware.

ATLAS Performance

ATLA

SLHC Performance 2010-2012

LHC performed extremely well in the three years of the first run.

In 2012, peak luminosity has been systematically above 7 1033 cm-2 s-1

Total accumulated luminosity was 23.3 fb-1, enough to firmly establish the Higgs discovery and its basic parameters. 3/9/2013Paolo Morettini - ICNFP 2013 5

ATLAS Performance

2012

20112010

ATLA

SATLAS Performance 2010-2012

ATLAS performance was as well satisfactory, with an average data taking efficiency exceeding 93% and a fraction of active channels of 95%

It is important to note that most of 2012 data was taken with an average number of pile-up events per crossing around 35, due to the 50 ns spacing. A data-taking environment more challenging than the one expected at design luminosity and 25 ns spacing.


ATLAS Performance

ATLA

STrigger performanceThe ATLAS trigger system demonstrated to be robust and flexible enough to follow the rapid LHC luminosity increase maintaining full efficiency.

Many algorithms (more than 500 trigger items) were developed to guarantee optimal selection.

Stability vs pile-up was a concern, but no problem observed so far.


ATLAS Performance

Single e, Et > 25 GeVEfficiency vs pile-up

ATLA

SHiggs physics perspectivesAs recognized in the recent European Strategy symposium, the priority after the consolidation of the Higgs discovery is to obtain precise measurement of the parameters of the new particle: Mass and width Quantum numbers Couplings and self-coupling Comparison with the SM

LHC has been recognized as the natural facility to complete these studies, but obviously an increase in luminosity would significantly enhance the achievable precision.


Motivations for the upgrade

ATLA

SBeyond the Standard ModelAn increase in luminosity would as well be beneficial to extend the range of the searches for SUSY particle and for other “exotic” processes.



SUSY particles at HL-LHC3 TeV for squarks

~ 2.5 TeV for gluinos400 GeV rise in sensitivity wrt

the L=300 fb-1 case

ttbar resonances at HL-LHC6.7 TeV L=3000 fb-1 leptons +

jets5.6 TeV L=3000 fb-1 dileptons4.3 TeV L=300 fb-1 leptons +

jets4 TeV L=300 fb-1 dileptons

ATLA

SLHC upgrade plan



ATLA

SMotivations for the upgradeBased on the experience of the first LHC run, we can say that ATLAS as is can successfully operate at 1034 cm-2s-1 and possibly more. However, the ultimate goal of accumulating 3000 fb-1 in more than 15 years at 5 x 1034 cm-2s-1 requires some intervention: Several detectors, especially close to the beam line,

will be damaged by the accumulated dose The large number of interactions per crossing (<m>

up to 150) will saturate read-out links and generate large occupancies.

A more and more selective trigger will be necessary to efficiently isolate the few interesting events



10

33 c

m-

2s-

15

10

34

cm-2s

-1

ATLA

SATLAS detector upgrade plan


LS1 ↠ PHASE 0 ℒ = 1034cm-2s-1

<m>=24100 fb-1 (2014-2017)

LS2 ↠ PHASE 1 ℒ = 2x1034cm-2s-1

<m>=50350 fb-1 (2019-2021)

LS3 ↠ PHASE 2 ℒ =5x1034cm-2s-

1<m>=1403000 fb-1 (2023-2030)

• Installation of the 4th Pixel Detector Layer

• Pixel Detector improvements

• DBM beam monitor• Silicon tracker cooling system replacement

• Muon EE chambers completion

• New Muon Small Wheel detector

• Upgrade of the central L1 trigger processor

• Topological L1 triggers

• L1 Calo granularity increase

• New “All Silicon” tracker

• New L0-L1 trigger schema

• Inclusion of track info at L1

• Upgrade of the calorimeter readout

• Upgrade of the muon spetrometer

Phase 0

In Progress…

ATLA

SPixel detector upgradeNeed to cure progressive radiation damage and mitigate inefficiencies due to pile-up effects. Two substantial interventions are in progress during LS1: Replacement of service

distribution panels, to cure malfunctioning channels, increase accessibility and bandwidth.

Installation of a 4th layer (IBL), close to the beam pipe(33-38 mm from the beam line).


Phase 0

New SQP

“old

” B

eam

Pip

eR

= 2

9 m

mIB

L se

tup

25 mm

31-40 mm

ATLA

SIBL technologies Originally thought as a LS2 intervention, the Pixel

upgrade was anticipated to guarantee a more robust tracking system and a less radioactive working environment.

New technologies prototyping Phase 2 upgrade: New FE chip (FE-I4) in 130 nm CMOS, with smaller cells (50

x 250 mm2) and faster output links


Phase 0

Pixel Read-out inefficiency vs LHC LuminosityFE-I3 FE-I4

b-tagging rejectionvs

pile-up

With IBL

Without IBL

ATLA

SIBL technologies Originally thought as a LS2 intervention, the Pixel

upgrade was anticipated to guarantee a more robust tracking system and a less radioactive working environment.

New technologies prototyping Phase 2 upgrade: New FE chip (FE-I4) in 130 nm CMOS, with smaller cells (50

x 250 mm2) and faster output links 3D sensors in the forward region (lower bias voltage,

immunity to bulk defects), planar, slim edge, n-in-n in the central region.


Phase 0

ATLA

SMore LS1 interventions… As a part of the IBL installation, we will replace the

beam pipe: the central part will be in beryllium, the outer part in aluminium.

The evaporative cooling system of Pixel and Strips will be replaced.

More Muon End-cap Extension chambers(EE) will be installed, to improve coveragein the 1.0 < |n| < 1.3 region.

Add specific neutron shielding Diamond Beam Monitor (DBM)

diamond pixel detector with IBL readout

Then, in this long shutdown, as in the following ones, many small interventions will be performed here and there to cure problems that cannot be addressed in a regular shutdown or to replace obsolete components (e.g. power supplies, readout elements, …) 3/9/2013Paolo Morettini - ICNFP 2013 16

Phase 0

EE

ATLA



LS1 ↠ PHASE 0 ℒ = 1034cm-2s-1

<m>=24100 fb-1 (2014-2017)

LS2 ↠ PHASE 1 ℒ = 2x1034cm-2s-1

<m>=50350 fb-1 (2019-2021)


1<m>=1403000 fb-1 (2023-2030)














Phase 1

Preparing TDR

ATLA

SMuon Small Wheel upgradeThe innermost layer of the muon endcap is extremely sensitive to beam background. While working fine at the moment, the existing detector would produce an excessive fake L1 rate at luminosities above 1034 cm-2s-1. Will be replaced with a new detector with higher position resolution (100 mm) and direction reconstruction capability (1 mrad) to select tracks pointing to the primary vertex.


Phase 1

ATLA

SNew Small Wheel impactFrom the detector technology point of view, NSW will use two solutions: Small strip Thin Gas Chambers (sTGC) for L1 trigger Micromegas (MM) for precision tracking

The new detector will ensure a strong reduction of single muon rates with a reasonable safety margin up to 5 x 1034 cm-2s-1


Phase 1

Muon L1 Rates vs pt threshold

NOW with NSW x3 reduction for pT(μ)>20 GeV at

1034 cm‐2s‐1

sTGC

MM

sTGC

ATLA

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Calorimetric trigger The granularity of the EM L1

trigger will be increased, to exploit shower longitudinal and transvers shape.

Better electron-jet separation will be achievable.

Will allow un-prescaled single electron triggers at Et ~ 25 GeV above 1034 cm-2s-1

Together with an update of the central L1 trigger processor, topological L1 triggers will be available.


Phase 1

ATLA

SFTKFTK is a track trigger processor.It can produce tracks with a quality similar to the off-line in ~25 ms. Based on CDF experience Pattern recognition is done

using associative memories, track fit with a FPGA processor.

In ATLAS, FTK uses L2 trigger data, but the output is ready at the beginning of L2 software processing.

Better HLT algorithms for b-tagging, t identification and lepton isolation will be available.


Phase 1

ATLA



LS1 ↠ PHASE 0 ℒ = 1034cm-2s-1

<m>=24100 fb-1 (2014-2017)

LS2 ↠ PHASE 1 ℒ = 2x1034cm-2s-1

<m>=50350 fb-1 (2019-2021)


1<m>=1403000 fb-1 (2023-2030)














Phase 2

LoI submitted

ATLA

SNew “All Silicon” trackerTo face the challenge of HL LHC ATLAS will need a new tracker: Progressive radiation damage

will make the old detector inefficient

More granularity and more bandwidth is needed to operate at 5 x 1034 cm-2 s-1, due to the large pileup.

The layout proposed in the LoI provides 14 points/track to |n| < 2.7 Pixel: 4 layers + 5 disks, 25

x 150 (in) / 50 x 150 (out) mm2

Strips: 5 layers + 7 disks stereo


Phase 2

ATLA

STracker layoutClearly there are many options under investigation, and the details of the tracker layout will be fixed later. The challenge is always the same: Produce a mechanical support

with the best possible thermal and mechanical characteristics and, at the same time, as light as possible.

Find room and power dissipation capabilities for the on-detector electronics and the links needed to transmit the enormous amount of data. Present estimate

2500-3000 lpGBT links at 9.6 Gb/s


Phase 2

ATLA

STDAQ upgradeOne interesting possibility open by the complete redesign of the tracker and by modern data transmission technologies is the inclusion of tracks at L1. This requires, however, some deep modification of the trigger strategy, as it is impossible to build tracks at full rate in few ms. The idea is to use a calorimetric and muon pre-trigger (called L0) to select events were tracks will be reconstructed. L0 signal will be sent only to tracker modules in selected space regions.


Phase 2

Level-0Rate 500 kHz, Lat. 6

msMuon + Calo

Level-1Rate 200 kHz, Lat. 20

msMuon + Calo + Tracks

ATLA

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Calorimeter upgrade No upgrade is required for the EM

and Hadronic calorimeter to run at HL LHC.

The FE electronics (both LAr and Tile) needs however to be replaced. The idea is to move off-detector data from each collision (no on-detector buffering) and do L0, L1 processing off detector.

Hadronic endcap is designed for 1000 fb-1. A replacement is considered.

Forward calorimeter (3.2 < |n| < 4.9) may have overheating problems at high luminosities. A complete new system could be installed or just a new calorimeter in front of the existing one.


Phase 2

ATLA

SMuon spectrometer upgrade


Phase 2

Extra layers with more resolution

High resolution forward

chambers

New trigger chambers

ATLA

SSummaryA sophisticated apparatus like ATLAS needs constant care to operate efficiently.

This is even more true if optimal performance has to be maintained over 20 years with a luminosity increase of a factor of 5 (and possibly more) compared to the original design.

ATLAS has a three stage upgrade plan, following the LHC upgrade, with the emphasis on: Replacing detectors damaged by radiation or

saturated by the luminosity increase. Add flexibility to the trigger system and

bandwidth to the readout. Replace obsolete components with newer and

more maintainable technologies. 3/9/2013Paolo Morettini - ICNFP 2013 28

ATLAS Detector : status and upgrade plans

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