22 Feb 2011






The ATLAS tracker system consists of three concentric layers: The pixel detectors, the Semi-Conductor Tracker (SCT) (link opens in a new window) (silicon strips) and the TRT straw-tube tracker. The SCT consists of 4 barrels and 2 endcaps, each with 9 disks. These detectors are now installed in the pit, and commissioning for physics started in late 2008.

Construction at RAL

The construction was a collaborative effort in which we (PPD & TD) worked very closely with colleagues from all over the world, but in particular UK University groups and Dutch colleagues in NIKHEF.

For the Barrel, we

  • Built 730 modules - a little over a quarter of the total number.
  • Made the cooling circuits.
  • Assembed the services to the carbon-fibre cylinders.
  • Supported module mounting at Oxford.

For the End-cap, we

  • Designed the support structures.
  • Made the cooling circuits.
  • Assembled the services to the carbon-fibre disks.
  • Supported the End-cap assembly at Liverpool.
  • Arranged the transport of the UK End-cap to CERN.

And in general for the whole SCT, we

  • Undertook performance studies to guide the design.
  • Oversaw much of the SCT and tracker engineering.
  • Designed most of the services from the detectors to the PPF1 patch panels.
  • Undertook much of the DAQ commissioning.

Operation of the SCT

Now we are actively participating in the operation of this detector. We have an on-going responsibility for the readout and detector controls​ and are part of the team ensuring the detector works as expected during data-taking.​