didier lacour cern hadron structure 2002 - herl'any slovakia september 22-271 status of the...

Didier Lacour CERN Hadron Structure 2002 - Herl'any Slovakia September 22-27

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Status of the ATLAS Detector Construction

Outline :Overall detector concept

Sub-systemsInner detectorCalorimetryMuon instrumentation

Magnet system

Experimental area

Didier Lacour CERN, for the ATLAS CollaborationHadron Structure 2002, Herl’any Slovakia


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ATLAS Collaboration

Albany, Alberta, NIKHEF Amsterdam, Ankara, Ann Arbor, LAPP Annecy, Argonne NL, Arizona, Arlington UT, Athens, NTU Athens, Baku, IFAE Barcelona, Bergen, Berkeley LBL and UC, Bern, Birmingham, Bonn, Boston, Brandeis,

Bratislava/SAS Kosice, Brookhaven NL, Bucharest, Cambridge, Carleton/CRPP, Casablanca/Rabat, CERN, Chinese Cluster, Chicago, Clermont-Ferrand, Columbia, NBI Copenhagen, Cosenza, INP Cracow, FPNT Cracow,

Dortmund, JINR Dubna, Duke, Frascati, Freiburg, Fukui, Geneva, Genoa, Glasgow, ISN Grenoble, Technion Haifa, Hampton, Harvard, Heidelberg, Helsinki, Hiroshima, Hiroshima IT, Indiana, Innsbruck, Iowa SU, Irvine UC,

Istanbul Bogazici, KEK, Kobe, Kyoto, Kyoto UE, Lancaster, Lecce, Lisbon LIP, Liverpool, Ljubljana, QMW London, RHBNC London, UC London, Lund, UA Madrid, Mainz, Manchester, Mannheim, CPPM Marseille, MIT, Melbourne,

Michigan SU, Milano, Minsk NAS, Minsk NCPHEP, Montreal, FIAN Moscow, ITEP Moscow, MEPhI Moscow, MSU Moscow, Munich LMU, MPI Munich, Nagasaki IAS, Naples, Naruto UE, New Mexico, Nijmegen, Northern Illinois,

BINP Novosibirsk, Ohio SU, Okayama, Oklahoma, LAL Orsay, Oslo, Oxford, Paris VI and VII, Pavia, Pennsylvania, Pisa, Pittsburgh, CAS Prague, CU Prague, TU Prague, IHEP Protvino, UFRJ Rio de Janeiro, Rochester, Rome I, Rome II, Rome III, Rutherford Appleton Laboratory, DAPNIA Saclay, Santa Cruz UC, Sheffield, Shinshu, Siegen,

Southern Methodist, NPI Petersburg, Stockholm, KTH Stockholm,Stony Brook, Sydney, AS Taipei, Tbilisi, Tel-Aviv, Thessaloniki, Tokyo ICEPP, Tokyo MU, Tokyo UAT, Toronto, TRIUMF, Tsukuba, Tufts, Udine, Uppsala, Urbana UI,

Valencia, UBC Vancouver, Victoria, Washington, Weizmann Rehovot, Wisconsin, Wuppertal, Yerevan

149 Institutions 1500 physicists

Collaboration composition


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Overall detector concept and basic design criteria

• Very good electromagnetic calorimetry for electron and photon identification and measurements, complemented by full-coverage hadronic calorimetry for accurate jet and missing transverse energy measurements;

• High-precision muon momentum measurements, with the capability to guarantee accurate measurements at the highest luminosity using the external muon spectrometer alone;

• Efficient tracking at high luminosity for high-pT lepton momentum measurements, electron and photon identification, -lepton and heavy-flavour identification and full event reconstruction capability at lower luminosity;

• Large acceptance in pseudo-rapidity () with almost full azimuthal angle () coverage everywhere.

• Triggering and measurements of particles at low-pT thresholds, providing high efficiencies for most physics processes of interest at LHC.

See also the talk of Anna Di Ciaccio on “Physic at LHC with ATLAS’’


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Dimensions are 22 m X 44 mTotal weight is about 7000 Tons

ATLAS detectorA Toroidal LHC ApparatuS


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The Inner Detector (ID) is contained within a cylinder of length 7 m and a radius of 1.15, in a solenoidal magnetic field of 2 T. The ID consists of three units: a barrel part extending over ± 80 cm, and two identical end-caps covering the rest of the cylindrical cavity.

For : Pattern recognition, momentum and vertex measurements, electron identification. With : a combination of discrete high-resolution semiconductor Pixels and SiliconTracker (SCT) in the inner part of the tracking volume, Continuous straw tube tracking detector with Transition Radiation capability (TRT) in its outer part.

Inner Detector (ID)

Typically, three pixel layers and eight strip layers (four space points) are crossed by each track. A large number of tracking points (typically 36 per track) is provided by the straw tube tracker (TRT), which provides continuous track-following with much less material per point and a lower cost.


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• In the barrel region, the high-precision detector layers are arranged on concentric cylinders around the beam axis, while the end-cap detectors are mounted on disks perpendicular to the beam axis.

• The pixel layers are segmented in R and z.

• The SCT detector uses small angle (40 mrad) stereo strips to measure both coordinates, with one set of strips in each layer measuring

• The barrel TRT straws are parallel to the beam direction.

System Position Area Resolution (m) 10^6 channels || coverage

Pixels 1 removal barrel layer

2 barrel layers

5 end-cap disks / side

0.2

1.4

0.7

R12, z=66

R12, z=66

R12, R=77

16

81

43

+/- 2.5

+/- 1.7

1.7-2.5

Silicon strips

4 barrel layers

9 end-cap wheels / side

34.4

26.7

R16, z=580

R16, R=580

3.2

3.3

+/- 1.4

1.4-2.5

TRT Axial barrel straws

Radial end-cap straws

36 straws/track

170 / straw

170 / straw

0.1

0.32

+/- 0.7

0.7-2.5

Inner Detector (ID)


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Pre-production Pixel sensors

High-granularity, high-precision measurements as close to the interaction point as possible.

3 barrels, 5 disks, 1500 barrel modules, 700 disk modules.

Each module is 62.4 mm long and 21.4 wide, with 61 440 pixel elements read out by 16 chips, each serving an array of 24 by 160 pixels.

Sensor pre-series from two producers have passed successful tests. First deliveries done on May June 2002

The developments of the hybridization, the local and the global supports proceed well.The Pixel sub-system now moves forward with moduleproduction and system tests.

Pixel Detector


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The ATLAS SCT consists of 4088 silicon modules. Each module is made up of 4 silicon sensors with 1536 readout strips.Individual strips are connected to FE amplifiers, discriminators and pipelines on the module. There are12 radiation hard ASICs, each containing 128 channels on the module.

Production is proceeding smoothly with over half the components delivered. The components of a module - 4 silicon sensors, a Cu/polyimide hybrid and pitch adaptor, and 12 ASICs - need to be carefully and precisely assembled onto a carbon and ceramic framework.

Semiconductor Tracker (SCT)

SCT end-cap module system test SCT barrel module system test


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Transition radiation tracker (TRT)

Production of the end-cap wheels has started at the two assembly sites, Gatchina andDubna, Russia

The TRT is a straw detectors, allowing a large number of measurements, typically 36, to be made on every track at modest cost. Electron identification capability is added by employing xenon gas to detect transition-radiation photons created in a radiator between the straws.

Each straw is 4 mm in diameter and equipped with a 30 mm diameter gold-plated wire, giving a fast response and good mechanical and electrical properties for a maximum straw length of 144 cm in the barrel. The total number of electronic channels is 420 000. Each channel provides a drift-time measurement, giving a spatial resolution of 170 mm per straw.

The barrel section is built of individual modules with between 329 and 793 axial straws each, covering the radial range from 56 to 107 cm. The two end-caps each consist of 18 wheels. The 14 wheels nearest the interaction point cover the radial range from 64 to 103 cm, while the last four wheels extend to an inner radius of 48 cm in order to maintain a constant number of crossed straws over the full acceptance.


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TRT barrel module TRT end-cap wheel assembly

During the year 2002, the TRT is focusing on final design issues and module/wheel construction.

The end-cap wheel construction has now started fully at the two sites, after initial start-up problems which are overcome. Barrel production has been resumed in August 2002.

Transition radiation tracker (TRT)


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CalorimetersHighly granular liquid-argon / lead electromagnetic sampling calorimetry covers the pseudo rapidity range ||<3.2.Over the pseudorapidity range ||< 1.8,it is preceded by a presampler detector.

The LAr calorimetry is contained in a cylinder with an outer radius of 2.25 mand extends longitudinally to 6.64 malong the beam axis. In the end-caps, the LAr technology is also used for the hadronic calorimeters (copper LAr detector withparallel-plate geometry) which share the cryostats with the EM end-caps.

The same cryostats also house the special LAr forward calorimeters (a dense LAr calorimeter with

rod-shaped electrodes in a tungsten matrix) which extend the pseudorapidity coverage to ||=4.9.

The hadronic barrel calorimeter is a cylinder divided into three sections: the central barrel and two identical extended barrels. It is based on a sampling technique with plastic scintillator plates(tiles) embedded in an iron absorber. The outer radius of the scintillator-tile calorimeter is 4.25 and its half length is 6.10 m.


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LAr e.m. CalorimetryThe EM calorimeter is divided into a barrel part and two end-caps.

It is a lead LAr detector with accordion-shaped Kapton electrodes and lead absorber plates over its full coverage. The accordion geometry provides complete symmetry without azimuthal cracks.

The total thickness of the EM calorimeter is 24 radiation lengths.

Over the region devoted to precision physics the EM calorimeter is segmented into three longitudinal sections. The strip section is equipped with narrow strips with a pitch of ~4 mm in the direction. This section acts as a ‘preshower’ detector, enhancing particle identification and providing a precise position measurement in.

The signals from the EM calorimeters are extracted at the detector inner and outer faces and sent to preamplifiers located outside the cryostats close to the feedthroughs.


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LAr e.m. Calorimetry

e.m. calorimeter Barrel End-Cap

Coverage || < 1.475 1.375 < || < 3.2

Longitudinal segmentation

3 samplings

3 samplings 1.5 < || < 2.5

2 samplings 1.375 < || < 1.5

2.5 < || < 3.2

Granularity ( x )

Sampling 1

Sampling 2

Sampling 3

0.003 x 0.1

0.025 x 0.025

0.05 x 0.025

0.025 x 0.1 1.375 < || < 1.5

0.003 x 0.1 1.5 < || < 1.8

0.004 x 0.1 1.8 < || < 2.0

0.006 x 0.1 2.0 < || < 2.5

0.1 x 0.1 2.5 < || < 3.2

0.025 x 0.025 1.375 < || < 2.5

0.05 x 0.025 1.5 < || < 2.5

Number of channels 102400 62208


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The absorber fabrication has progressed in a steady pace, with about 60% for the end-caps and about 70%for the barrel completed.

Stacking and cabling of the modules proceeds at 3barrel and 2 end-cap assembly sites.

Completion is expected for spring 2003 (barrel) and fall 2003 (end-caps).

LAr e.m. barrel and end-cap modules


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The LAr hadronic end-cap series production continues to run smoothly: 107 out of 134 modules (including spares) have been completed, and 83 cold tested and accepted.

Assembly of three series frontmodules ready for cold testing

LAr Hadronic End-Cap calorimeters

Each HEC consists of two independent wheels, of outer radius 2.03 m. The upstream wheel is built out of 25 mm copper plates, while the cheaper other one, farther from the interaction point, uses 50 mm plates. In both wheels, the 8.5 mm gap between consecutive copper plates is equipped with three parallel electrodes, splitting the gap into four drift spaces of about 1.8 mm.

The readout electrode is the central one, which is a three layer printed circuit, as in the EM calorimeter.


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LAr end-cap calorimeter system test and calibration set-up, with EM and HECmodules installed in the cryostat at the SPS H6 test beam test beam of this year.

Test beam cryostat


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The LAr forward calorimeter module assembly is now also in full swing.The absorber structures for the first side is almost complete and for the second side work is well on its way.

FCAL2 and FCAL1

assemblyfor the first

side

LAr forward calorimeter

The FCAL consists of three sections : the first one is made of copper, while the other two are made out of tungsten. In each section the calorimeter consists of a metal matrix with regularly spaced longitudinal channels filled with concentric rods and tubes. The rods are at positive high voltage while the tubes and matrix are grounded.


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LAr Barrel Cryostat and Feedthroughs

The barrel cryostat is at CERN and essentially ready for the detector installation:

•Integration work is now finished •All feedthroughs installed (signal and HV)•All cryolines installed •Leak tests successfully done

EM calorimeter installation : Nov 2002 to June 2003

Install solenoid, final seals, pump lineand final cryostats tests : July 2003


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LAr End-Cap Cryostats and Feedthroughs

The first end-cap cryostat (side C) has been manufactured. Global leak and pressure tests done at the end of 2001. Cryogenics tests done in February 2002.

The first End-Cap Cryostat is now at CERN

Detector insertion : Nov 2002 – Aug 2003

Final cryogenics tests : Sep 2003.

The second End-Cap cryostat (side A) is planned to be delivered to CERN: Oct 2002


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The major integration activities have started in Hall 180 where the modules will be assembled into half-barrel rings and wheels for the end-caps, and then introduced into the barrel and the two end-cap cryostats respectively

The considerable pre-operation activities will include complete cold tests of the three fully loaded LAr calorimeter units (as well as the solenoid for the barrel) with test electronics

HEC wheels assembly and rotation tool Assembly of eight EM barrel modules

LAr Integration in Hall 180 at CERN


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Tile Calorimeter

Steel absorber structure

Photomultiplier

Plastic scintillator

Wavelength Shifting Fiber (WLS)

Sampling calorimeter using iron and scintillating tiles

Total number of channels : 10000

Mechanics series production is progressing very smoothly at all sub-module and module assembly sites, nearing completion

Almost 85% of all modules are at CERN and equipped with their optical components, ready for the initial Cs-source calibration


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Muon spectrometer

The outer chambers of the barrel are at a radius of about 11 m. The half-length of the barrel toroid coils is 12.5 m, and the third layer of the forward muon chambers is located about 23 m from the interaction point.

The conceptual layout of the muon spectrometer is based on the magnetic deflection of muontracks in the large superconducting air-coretoroid magnets.

In the barrel region, tracks are measured in chambers arranged in three cylindrical layers around the beam axis.In the transition and end-cap regions,the chambers are installed vertically, also in three stations.


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Muon Spectrometer Instrumentation

Alignment system in the barrel

Over most of the -range, a precision measurement of the track coordinates in the principalbending direction of the magnetic field is provided by Monitored Drift Tubes (MDTs).

At large pseudorapidity and close to the interaction point, Cathode Strip Chambers (CSCs) with higher granularity are used in the innermost plane over 2 <||< 2.7.

Resistive Plate Chambers (RPCs) are used in the barrel.Thin Gap Chambers (TGCs) are used in the end-cap regions.

RPC

TGS

RPC

TGS

MDT

CSC

http://m.home.cern.ch/m/muondoc/www/software/Database/PhotoGallery/RPC_Detail.gif


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Muon Precision Chambers MDTs

In terms of series MDT tubes about a third havebeen assembled and tested, rejected tube rates are well below the acceptable level

The quality of sample series chambers is regularly monitored with one X-ray facility, andall sites are found to fulfill the required high accuracy

The production planning conforms to the required installation dates for the initial detectorconfiguration

End-cap MDT chamber

Pre-series FE MDT electronics is workingin first chamber stations, and the final version Is being tested now


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The muon detector integration is very closely linked to the overall detector integration, and major work has progressed together with Technical Coordination on (movable) supports, shielding, services routing from the ID and calorimeters, and access scenarios, leading to new fixed baselinedimensionsThe large system test facility, both for projective end-caps and barrel sectors, in the SPS H8 beam is now becoming operational for first series chambers tests performed this year

Muon Integration and System Aspects

SPS H8 systemtest structures

Monitored driftchambers tested

during august 2002

http://documents.cern.ch/cgi-bin/setlink?base=PHO&categ=photo-ex&id=0208006


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Magnet system

The ATLAS superconducting magnet system is an arrangement of a central solenoid (CS) providing the Inner Detector with magnetic field, surrounded by a system of three large air-core toroids generating the magnetic field for the muon spectrometer.

The overall dimensions of the magnet system are 26 m in length and 20 m in diameter. The two end-cap toroids (ECT) are inserted in the barrel toroid (BT) at each end and line up with the CS. They have a length of 5 m, an outer diameter of 10.7 m and an inner bore of 1.65 m. The CS extends over a length of 5.3 m and has a bore of 2.4 m.

The CS provides a central field of 2 T with a peak magnetic field of 2.6 T at the superconductor itself. The peak magnetic fields on the superconductors in the BT and ECT are 3.9 and 4.1 T respectively.


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Barrel Toroid

Production of the main components of the Barrel Toroid coils is well advanced in industry.

Two vacuum vessels have been delivered to CERN by Felguera Construcciones Mecanicas.

Three coil casings have been completed at ALSTOM Power Switzerland .

The tested ATLAS Central Solenoid was delivered to CERN from Japan, in September 2001.It is now stored away, and ready for integration into the LAr barrel cryostat in 2003.


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End Cap Toroid

Cooling Circuit

Coil ModulesKeystone Box Module

Axial Force Tie Rods

Engineering & Monitoring @ RAL, NIKHEF

The two vacuum vessels were delivered to CERN by Schelde Exotech, Netherlands.


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Experimental Area

Underground civil engineering will end in Spring 2003

Most of the surface building will be handed over to ATLAS this year (Oct-Nov 2002)

ATLAS will start installation at Point-1 in April 2003


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Excavation ended.


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9 months of operation in the pit, starting end of 2003

Engineering pre-study done (CEA)

It needs now the final engineering work (including tooling)

Installation


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SummaryInner DetectorComponent fabrication is in general well under way. Progress on many critical items (electronics).Just at the threshold of module production start-up (Pixels, SCT)

CalorimetryMore than half of the modules constructed!Integrations and pre-assemblies are a focus of major activities.

Muon instrumentationChamber construction is now well underway at many sites.The large system test facility at H8/CERN is operational.

Magnet systemSolenoid fabrication complete, final integration still to come.Real visible construction progress on the toroids.


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The detector construction is in general coming well along the planning for the initial staged detector, operational for full commissioning in the second half of 2006.

More and more large components and modules of the detector (sub-) systems, are being delivered to CERN.

Large pre-assembly and module integration activities have started.

Conclusion

A Higgs event in ATLAS

didier lacour cern hadron structure 2002 - herl'any slovakia september 22-271 status of the...

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