Heat exchangers in the ATLAS liquid argon calorimeter

The Liquid Argon Calorimeter plays a central role in the future ATLAS detector at LHC. It is built from two end-caps and one barrel, housed in three separated cryostats. While operating, the cryostats will be filled with liquid argon at a temperature of approximately 87 K. Before the cryostats are filled with liquid argon, the calorimeter must be cooled down from ambient temperature to the temperature of filling. The Liquid Argon Calorimeter will be cooled down at least twice. First in the CERN West Area for cold tests, and a second time in its final position in the underground cavern of the ATLAS detector. Estimation of the cool-down time is therefore of significance.This diploma thesis evaluates the cool-down time of the Barrel Liquid Argon Calorimeter, which is defined as the time needed to cool down from ambient temperature to the temperature in which the cryostat can be filled with liquid argon...