In each final-focusing section, we constantly need to get rid off about 200 watts of power. This corresponds to the heat generated by a couple of strong light bulbs, assuming they burn inside the beam pipe. At ultra-low temperatures and in the middle of a superconducting magnet, this is a major engineering challenge. The helium absorbs the excess heat generated by the beam, transports it to a heat exchanger inside the vacuum vessel, and a separate stream of liquid helium carries the heat outside the vessel, where refrigerating units re-cool the helium. Fermilab's first LHC prototype magnet will be ready around the end of the year.
Technicians currently install the superconducting coils.
Soon the steel yoke will be in place. Next, they will outfit the prototype with supports and pipes of the cooling system. Once all equipment is installed, we carefully slide the whole construction into the vacuum vessel. Next summer, after completing the prototype tests, production and final assembly of the magnets will start. Fermilab will ship the last quadrupole magnet to CERN in 2004, allowing physicists there to continue exploring the secrets of matter at the smallest scales.