1. ATLAS SCT End-Cap C Integration 1.Introduction: to the SCT within ATLAS 2.End-Cap C Reception at CERN 3.Final Assembly 4.Integration with the TRT 5.Combined Testing Paul Bell Christmas Meeting December 2006

2. Paul Bell Christmas 2006 The Inner Detector and the SCT Within ATLAS A side Barrel C side Z

3. The 9 disks of each end-cap are tiled with a total of 986 modules Modules were constructed in different sites worldwide and shipped to Liverpool (Nikhef for EC-A) for assembly to disk, and for disk insertion to the carbon-fibre support cylinder Modules consist of two silicon wafers with 768 readout strips, back to back At one end, “hybrid” circuit holds FE chips which read out the strips Readout is binary: 6 chips per side (dealing with 128 channels each) providing shaping, amplification, discrimination against threshold and pipeline memory storage awaiting L1 Background: The Construction of the SCT Paul Bell Christmas 2006

4. SCT End-Cap C at a Glance (as it left Liverpool)

5. Paul Bell Christmas 2006 Temporary Bosch profile support structure Services thermal feed through Disk 1 end (towards interaction point) “The cylinder” with copper ground sheet Low Mass Tapes Data/Command Fibres Disk 9 end (where its plugged in) SCT End-Cap C at a Glance (as it left Liverpool) Temporary Patch Panel (TPP)

6. February/March SCT EC-C arrived CERN Feb 23rd after a three day journey by road from Liverpool Four weeks of reception testing covered: Electrical connectivity: Resistance checks from TPP to each module Optical connectivity: All harnesses checked Cooling circuits: All 36 cooling circuits leak checked  Problems identified: Found ~100 connectivity problems at the TPP (“temporary interconnects” – not on the EC) Also found electrical disconnections at PPF0 (between disks and cylinder)  Several weeks to investigate and repair Arrival and Reception Tests Paul Bell Christmas 2006 Checking the disk alignment: A pair of telescopes positioned at the disk 1 end and precision “spectacles” at the disk 9 end defined two lines of sight, passing through apertures of decreasing size in the disks.

7. April For insertion to the TRT, the SCT had to be first transferred to the cantilever stand Move to Cantilever Stand Paul Bell Christmas 2006

8. April For insertion to the TRT, the SCT had to be first transferred to the cantilever stand Wheels were added to the Bosch support frame and it was wheeled over the stand Move to Cantilever Stand Paul Bell Christmas 2006

9. Move to Cantilever Stand April For insertion to the TRT, the SCT had to be first transferred to the cantilever stand Wheels were added to the Bosch support frame and it was wheeled over the stand Electrical rework was still on-going, so the EC spent several weeks half on the beam, allowing space around the TPP to work: (Had to move here to create space for end- cap A which arrived at Easter) Paul Bell Christmas 2006

10. May SCT operates at -7degC in a nitrogen environment; separate volume from the room temperate CO 2 of the TRT:  end-cap has its own thermal enclosure Seal at the inner diameter provided by the Inner Thermal Enclosure (ITE): carbon fibre cylinder with foam layer and copper ground sheet ITE was inserted by rolling along the cantilever beam on carriages: sealed and electrically connected at each end (forms faraday cage as well as gas seal) Construction of Thermal Enclosure

11. June TE completed at both ends with a gas and grounding & shielding membrane July/August Before adding the Outer Thermal Enclosure, it was found that the optical fibres needed to be relayed along the cylinder more efficiently  Complete rechecking of electrical continuity then required, several weeks delay introduced With TE complete, leak checking began: Completion of End-Cap Paul Bell Christmas 2006

12. 987654321 Average All disks – Single Disks = -7e STDEV All disks – Single Disks = 23e Average CERN - Liverpool = 115e STDEV CERN - Liverpool = 70e Liverpool ~ 0°C CERN ~ 25°C Δσ ~ 5e / °C Electrical Testing Inside Thermal Enclosure September Ran 1/8 of a slice through all disks with cooling for proper noise studies with the modules now inside their close-to-final grounding/shielding environment Paul Bell Christmas 2006

13. October TRT was transferred to trolley, rails installed and aligned on the floor Rolled TRT over the SCT on the beam Transferred weight of SCT to the rails in the trolley; performed final survey of the two detectors Integration to TRT Paul Bell Christmas 2006

14. November/December Scintillators set up in the test area of SR1 for the cosmic trigger PS cabling, cooling and DCS prepared Connected 1 whole quadrant (quarter slice through all 9 disks) Ran cooling and performed noise scans of those 247 modules  This is where I joined the HLT… Several weeks of cosmic events collected Ahead… Cosmic data taking now finished as of 10 th December: collected ~150k events January will be spent preparing for pit installation (February?) Paul Bell Christmas 2006 SCT/TRT Combined Testing

15. Showed at the last Christmas meeting the plan for the SCT integration: 1. Reception testing (basic connectivity tests) 2. Transfer to cantilever beam and assembly of thermal enclosure 3. Testing inside thermal enclosure (including noise performance) 4. Integration with TRT 5. Combined testing with TRT  At that time envisaged completion mid-September 2006 We lost ~three months in total, mainly to the reworking of the fibres along the cylinder and to the early reworking of the temporary electrical connections We avoided cutting corners on the testing: an extra testing stage was effectively introduced following the fibre rework; cosmic tests were not originally foreseen Overall: no insurmountable problems, completion on a timescale compatible with the global ATLAS installation schedule. Paul Bell Christmas 2006 Summary