Perfluorocarbons and their use in cooling systems for semiconductor particle detectors

Abstract We report on the development of evaporative fluorocarbon cooling for the semiconductor pixel and micro-strip sensors of inner tracking detector of the ATLAS experiment at the future CERN large hadron collider (LHC). We proceeded with studies using perfluoro- n -propane (3M-“PFG 5030”; C 3 F 8 ), perfluoro- n -butane (3M-“PFG 5040”; C 4 F 10 ), trifluoro-iodo-methane (CF 3 I) and custom C 3 F 8 /C 4 F 10 mixtures. Certain thermo-physical properties had to be verified for these fluids. Sound velocity was calculated for the pure fluids and custom mixtures. A sonar instrument was developed for the measurement of sound velocity in the above fluids at a variety of temperatures and pressures. Irradiation studies were made on the fluids using neutrons and gamma rays to determine their suitability for use in the high radiation environment at LHC.