Thermal analysis of one LHC tunnel octant

Some of the electronic equipment to be installed in the rack space under the future LHC dipoles and quadripoles is expected to dissipate considerable heat, putting at risk the integrity of the equipment itself and causing thermal strains on the QRL (cryogenic distribution line) and cryostat vacuum vessels. Moreover, the ventilation injection and extraction points being separated by approximately 2.5 Km (one octant), a significant increase in the air bulk temperature is also expected along the distance. Further to a simple heat balance, three alternatives have been analysed to reduce the vacuum vessels exposure to the heat dissipated by the electronic equipment.