Didier Lacour CERN Hadron Structure Herl'any Slovakia September Status of the ATLAS Detector Construction Outline : Overall detector concept Sub-systems Inner detector Calorimetry Muon instrumentation Magnet system Experimental area Didier Lacour CERN, for the ATLAS Collaboration Hadron Structure 2002, Herl’any Slovakia

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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’’

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Dimensions are 22 m X 44 m Total weight is about 7000 Tons ATLAS detector A Toroidal LHC ApparatuS

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 Silicon Tracker (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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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. SystemPositionArea Resolution (  m) 10 ^6 channels |  | coverage Pixels 1 removal barrel layer 2 barrel layers 5 end-cap disks / side R  12, z=66 R  12, R= / / Silicon strips 4 barrel layers 9 end-cap wheels / side R  16, z=580 R  16, R= / TRT Axial barrel straws Radial end-cap straws 36 straws/track 170 / straw / Inner Detector (ID)

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 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 module production and system tests. Pixel Detector

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 are 12 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 testSCT barrel module system test

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Transition radiation tracker (TRT) Production of the end-cap wheels has started at the two assembly sites, Gatchina and Dubna, 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 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September TRT barrel moduleTRT 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 Transition radiation tracker (TRT)

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Calorimeters Highly 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 m and extends longitudinally to 6.64 m along the beam axis. In the end-caps, the LAr technology is also used for the hadronic calorimeters (copper LAr detector with parallel-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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September LAr e.m. Calorimetry The 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September LAr e.m. Calorimetry e.m. calorimeterBarrelEnd-Cap Coverage |  | < < |  | < 3.2 Longitudinal segmentation 3 samplings 3 samplings 1.5 < |  | < samplings < |  | < < |  | < 3.2 Granularity (  x  ) Sampling 1 Sampling 2 Sampling x x x x < |  | < x < |  | < x < |  | < x < |  | < x < |  | < x < |  | < x < |  | < 2.5 Number of channels

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 3 barrel 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 front modules 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September LAr end-cap calorimeter system test and calibration set-up, with EM and HEC modules installed in the cryostat at the SPS H6 test beam test beam of this year. Test beam cryostat

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 assembly for 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 line and final cryostats tests : July 2003

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 Cryogenics tests done in February The first End-Cap Cryostat is now at CERN Detector insertion : Nov 2002 – Aug 2003 Final cryogenics tests : Sep The second End-Cap cryostat (side A) is planned to be delivered to CERN: Oct 2002

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Tile Calorimeter Steel absorber structure Photomultiplier Plastic scintillator Wavelength Shifting Fiber (WLS) Sampling calorimeter using iron and scintillating tiles Total number of channels : 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 muon tracks in the large superconducting air-core toroid 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Muon Spectrometer Instrumentation Alignment system in the barrel Over most of the  -range, a precision measurement of the track coordinates in the principal bending 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Muon Precision Chambers MDTs In terms of series MDT tubes about a third have been 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, and all sites are found to fulfill the required high accuracy The production planning conforms to the required installation dates for the initial detector configuration End-cap MDT chamber Pre-series FE MDT electronics is working in first chamber stations, and the final version Is being tested now

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 baseline dimensions The 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 system test structures Monitored drift chambers tested during august 2002

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 It is now stored away, and ready for integration into the LAr barrel cryostat in 2003.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September End Cap Toroid Engineering & RAL, NIKHEF The two vacuum vessels were delivered to CERN by Schelde Exotech, Netherlands.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Excavation ended.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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

Didier Lacour CERN Hadron Structure Herl'any Slovakia September Summary Inner Detector Component fabrication is in general well under way. Progress on many critical items (electronics). Just at the threshold of module production start- up (Pixels, SCT) Calorimetry More than half of the modules constructed! Integrations and pre-assemblies are a focus of major activities. Muon instrumentation Chamber construction is now well underway at many sites. The large system test facility at H8/CERN is operational. Magnet system Solenoid fabrication complete, final integration still to come. Real visible construction progress on the toroids.

Didier Lacour CERN Hadron Structure Herl'any Slovakia September 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 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