ATLAS Construction:A Status Report

Lake Louise Winter InstituteFebruary 2006

Anna SfyrlaUniversity of Geneva

On behalf of the ATLAS Collaboration

27 km circumferenceoperating luminosity 1034cm-2s-1

bunch spacing 25ns -> ~23 collisions per bunch crossing

7 TeV beam energy

LHCA Large Hadron Collider

ATLASA Toroidal LHC Apparatus

Length : ~ 46 m Radius : ~ 12 m Weight : ~ 7000 tons~ 108 electronic channels~ 3000 km of cables

General purpose p-p detectorClassic layered structureShape defined by the ~4T toroidal magnet

The toroid systemSuperconducting air core toroids

provide the (~4T) magnetic field for the muon spectrometer

Barrel Toroid8 separate coils

Endcap Toroid8 coils in a common cryostat

Barrel toroid mechanical installation complete.Electrical and cryogenic connections being made now,

To be completed for the first test by Spring 2006!

Endcaps under Construction. Tests to be performed at 80K

before moving to cavern

Muon Spectrometer

Precision Tracking- Cathode Strip Chambers (CSC)

- Monitored Drift Tube Chambers (MDT)

Triggering- Resistive Plate Chambers (RPC)

- Thin Gap Chambers (TGC)

Barrel Construction Innermost chambers well advanced Middle and outer chamber integration with RPCs and cosmic testing – in progressBarrel InstallationAlready started and in good progressTo be completed by AugustBarrel CommissioningCombined cosmics run together with Tile Calo

Endcap ‘Big Wheel’ endcap under assembly Current speed not sufficient, being addressed with increased resources (plan in progress)

CalorimetryElectromagnetic

Calorimeter- LAr sampling

- Accordion shaped absorber plates

Calorimeter barrel (+central solenoid) into their final position at the center of ATLAS (endcap installation in

process)(November 2005)

Hadronic Calorimeter- LAr sampling in the inner FWD part

- Iron/Scintillator sampling (Tile) surrounding the LAr parts

A cosmic ray muon registered in the barrel Tile Calorimeter

The Tracking System- Cylindrical cavity, length:6.8m, diameter:2.2m- Axial field of max strength 2T (superconducting solenoid in front of the ECAL- Precision tracking, 2ndary vertex detection, good time resolution vsvs big amount of material (FE electronics, power cables, cooling pipes…)

PixelsSi Pixel Detectors

3 Barrels & 2*3 Endcap Disks~0.8*108 channels

3 space points4cm < R < 12cm

Big challenge: rad-hardness

SemiConductor Tracker (SCT)

Si Strip Detectors4 Barrels & 2*9 Endcap Disks

~6*106 channels4 space points

30cm < R < 52cm

Transition Radiation Tracker

(TRT)Straw tubes

~50K Barrel tubes & ~ 320K Endcap tubes

~4*105 channels36 space points

R < 1mElectron ID

The Tracking System-- pixels --

2 completed pixels disks

2.2M channels each

Probably the most challenging detector part of ATLAS!

Very good progress in Pixel Sensors, Front End electronics and Readout, Mechanics, Staves and DisksSchedule affected by technical problems:- Faulty potting of controller chip on a fraction of barrel modules (solved)- Delamination of a fraction of barrel stave supports (solved)- Corrosion leaks in the barrel cooling tubes (highest priority is given to an optimum strategy for repair and rebuilding of staves)

Schedule risk for the in time installation for the start up.(the Pixel sub-system can be installed independently from the rest of the ID)

Completed barrel stave

The Tracking System-- SCT --• Barrel assembly

completed at Oxford

• January-August 2005: Barrels shipped at CERN.

• July-September 2005: 4-barrel + thermal

enclosure integration

•99.7% of >3M channels fully functional

inserting B6 into the thermal

enclosure (7/05)

a completed endcap disk

Barrels and services

• All disks for the 1st endcap finished, almost finished for the second

one.• Disks assembled to

endcaps in Liverpool and NIKHEF

• New fabrication of LMTs (Low Mass Tapes for electrical services) because of material

failures is on schedule

The Tracking System-- TRT --

Cosmic rays recorded by the TRT

• Barrel modules built and tested in US, re-tested at CERN• Integration of modules, FE electronics boards, gas and cooling with space frame completed• Acceptance tests completed• Tests with cosmic rays performed since last summer • Leaks in the barrel cooling line manifolds, due to bad brazing:redesign was adopted, and has been implemented.

• Endcap wheels built and tested in Russia, re-tested at CERN• Acceptance tests completed, integration in progress.

The Tracking System-- SCT & TRT integration --

• After reception tests,SCT to ‘cantilever’ stand• Test seals and functionality• Align ID rails• TRT on ‘ID trolley’• Roll trolley over SCT maintaining alignment• Combined testing…

For Barrels and Endcaps similar procedure but

different tooling

The Tracking System-- SCT & TRT integration --

Initial tests to take place:-Performance tests of SCT and TRT-Once the above tests accomplished, emphasis will be given in cosmics run (~4wks)

Lowering to the pit will take place at around June Friday, 17 February 2006

ATLASConstruction Status Summary

• The installation schedule is very tight for the coming 15 months

• Global commissioning of ATLAS is planned to take place April 07 – June 07, followed by ATLAS combined cosmics tests, planned for June 07 – August 07

• Last year’s progress has been very impressive, but the next year will be critical for the on schedule detector completion

• Despite the delays (ex. Barrel Muon installation) and the still existing critical areas (ex. Pixels), large collective efforts are taking place to

rearrange the schedule, in order to minimize the overall impact.

ATLASOverall summary installation schedule

Version 7.09