atlas sct end-cap c integration 1.introduction: to the sct within atlas 2.end-cap c reception at...
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ATLAS SCT End-Cap C Integration
1. Introduction: to the SCT within ATLAS2. End-Cap C Reception at CERN3. Final Assembly4. Integration with the TRT5. Combined Testing
Paul BellChristmas Meeting
December 2006
Paul Bell Christmas 2006
The Inner Detector and the SCT Within ATLAS
A side
BarrelC side
Z
• 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
Paul Bell Christmas 2006
SCT End-Cap C at a Glance (as it left Liverpool)
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)
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.
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
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
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
Paul Bell Christmas 2006
May
• SCT operates at -7degC in a nitrogen environment; separate volume from the room temperate CO2 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
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
800
1000
1200
1400
1600
1800
2000
Inp
ut
No
ise
(EN
C)
Liverpool Single Disks All Disks
9 8 7 6 5 4 3 2 1
Average All disks – Single Disks = -7e
STDEV All disks – Single Disks = 23e
Average CERN - Liverpool = 115e
STDEV CERN - Liverpool = 70e
<T> Liverpool ~ 0°C
<T> 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
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
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 10th December: collected ~150k events
• January will be spent preparing for pit installation (February?)
Paul Bell Christmas 2006
SCT/TRT Combined Testing
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