Prime wires for ATLAS

In an award ceremony on 3 September, ATLAS honoured the French company Axon Cable for its special coaxial cables, which were purpose-built for the Liquid Argon calorimeter modules.

Working for CERN since the 1970s, Axon' Cable received the ATLAS supplier award last week for its contribution to the liquid argon calorimeter cables of ATLAS (LAL/Orsay, France and University of Victoria, Canada), started in 1996. Its two sets of minicoaxial cables, called harnesses "A" and "B", are designed to function in the harsh conditions in the liquid argon (at 90 Kelvin or -183°C) and under extreme radiation (up to several Mrads).
The cables are mainly used for the readout of the calorimeters, and are connected to the outside world by 114 signal feedthroughs with 1920 channels each. The signal from the detectors is transmitted directly without any amplification, which imposes tight restrictions on the impedance and on the signal propagation time of the cables.

Bundled in harnesses of 64 cables each, they are fitted with custom-developed connectors at each end, which are much smaller than normal connectors since there is no room to spare in the calorimeter. Given the total number of harnesses (more than 6000) and their average length, the total supply amounts to about 1000 km of cable.
The cables form an essential part of the project, since without prime cables the detector would not be functional; "there would be no signal" without the cables and feedthroughs, says Paul Poffenberger, from the University of Victoria. The cables are designed for 10 years of operation, and therefore have to be very reliable.
At the award ceremony, Peter Jenni, the ATLAS spokesperson, commented not only on the high quality of the cables - during the testing of the cables there were no failures - but also on the good teamwork. "With a high level of professionalism and a devotion to the tight schedule of the project, Axon Cable has contributed a crucial part to the complex puzzle of the Liquid Argon calorimeter."