Elementary Electromagnetic Particle Physics
The Atlas Project

The Kapton Coated Copper Cable Home Page


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Arizona Atlas

Cable Overview

The cables that will carry the signal from the electrodes to the electronics are specially made Kapton coated copper co-axial. Each cable is 308 centimeters long and there is a total of 128 cables needed for Fcal 1 alone. Fcal 2 will require 64 cables that are 223 centimeters in length and Fcal 3 requires 32 cables, 207 centimeters long. These cables connect to the electrodes on the face of each forward calorimeter and carry the signal to the summing boards.


Kapton Cable Harness

Mock-ups to Test Specific Features of the Cables

Cable Mock-up on Module 0

The attachment of the cables to the electrodes on the face of the Forward Calorimeters will be done shortly before the devices are placed into the Endcap Cryostat. Since it will be to late to resolve last minute problems with cable features at that time, mock-ups of the different cable features must be addressed now. One of those features is how well the cables from an individual phi slice of the Fcal 1 module fit down the cable trough and how flat can they lay across the face of the module. Keeping in mind that the cables from all electrodes are the same length a design must be incorporated that allows the most consistant travel length over the face of the module. All of the cables must end at the same connector without kinks or sharp turns.

[Mod 0 Phi slice cable!]
One Phi slice of Module 0 fully cabled

Cable Mock-up on PVC, full size model

This PVC mock-up of a full-size Fcal 1 module has been built to review the cabling pattern for the electrodes. It will be used to determine the best procedure to follow during final cabling of the Forward Calorimeter at CERN. The wires that are attached to the face plate have the same diameter as the Kapton cables we will use. The different colors represent four complete phi sections. Directly behind the PVC mock-up is a full-size drawing of the HEC modules and how the Fcal summing boards will be mounted with cabling out to the feed-throughs. These cable paths will need to be verfied also prior to final assembly into the endcap at CERN.

[Leif Shaver with PVC Mock-Up!]
Leif Shaver with PVC Mock-Up

Tests on Cables for Specific Performance

Continuity Tests for Cables

The Time-Domain Reflectometer (TDR) is a short-range cable tester that sends an electrical pulse down a cable and detects any reflections made by discontinuities. The Tektronix 1502C is sensitive to impedance changes, any problems along the length of the cable will be displayed as changes in the impedance. This tester is capable of finding shorts, opens, defects in the shield, foreign substances in the cable, kinks, and more.

Tektronix Time-Domain Reflectometer (TDR), Model 1502C

Tests for Cold Cable Continuity

Each cable will also be tested with the TDR device while in Liquid Argon (LArG) since this is the medium it will be operated in for ATLAS. Initial tests for continuity will be done on each cable at room temperature and the changes in impedance documented. Then the cables will be submerged in LArG and the same impedance documentation will be done. Each cable used with the Forward Calorimeters will have the TDR measurement, for both room temperature and LArG operation, recorded and archived.

Experimental Elementary Particle Physics Departmental Telephone: (520) 626-96