atlas sct end-cap c integration 1.introduction: to the sct within atlas 2.end-cap c reception at...

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