The Liquid Argon Hadronic Endcap Calorimeters (HEC) standing at each end of the Atlas detector are designed to detect hadrons emitted at small angles (5 - 25 degrees) relative to the two proton beams, where the radiation is most intense. The HEC consists of 32 triangular shaped modules arranged in a ring, and each module is made of several 2.5 cm thick copper plates positioned 8 mm apart in a bath of liquid argon that is subjected to a large electric field.
The HECs were designed and partially built at TRIUMF. Their assembly at CERN was overseen by TRIUMF personnel, who designed the specialized tooling required for this challenging task.
The radiation-hard front-end electronics for the liquid argon calorimeters were designed by a TRIUMF scientist at the University of Alberta. TRIUMF engineers made major contributions to the design and construction of the forward calorimeters (FCAL) and a TRIUMF scientist led the project to construct one third of the FCAL (FCAL2) at Carleton University. TRIUMF engineers contributed to the design, construction, and installation of the complex and delicate feedthroughs, which bring cables from the endcap and forward calorimeters out of the cryostat.