Cooling for magnets
The world’s largest particle accelerator is the annular Large Hadron Collider (LHC). It has a circumference of 27 kilometers and is located about a hundred meters underground beneath the French-Swiss border near Geneva. The LHC is used to conduct research into the composition of matter and the processes that determined the creation of the universe. The LHC has a total of eight extremely powerful superconducting magnets. They are operated at a temperature of minus 271 degrees Celsius. Helium is used here to maintain the constant temperature required for superconductivity. When the accelerator has to be cooled down again after use, the helium is first pre-cooled with liquid nitrogen from Messer. Two subsequent process steps continue to cool down the noble gas till the magnets reach the target temperature.