The first cryogenic feedbox designed to supply electricity to the superconducting magnets for one of eight arcs has been installed at Point 8 of the Large Hadron Collider (LHC). This milestone is the precursor to the cool-down of sector 7-8, scheduled for the coming months. Researchers will position a total of 16 such feedboxes at either end of the eight arcs, forming the ends of the continuous sections of cryostat. Each one weighs 12.7 t, is 10 m long and must withstand a pressure of 0.25 MPa.
Power leads, the lower extremities of which are immersed in liquid helium, bring the electrical power from room temperature to cryogenic temperature. Helium gas actively cools them and is injected at their base at 20 K and comes out at room temperature at the top. The power leads use ceramic high-temperature superconductor to limit the heat loads – the first time that these materials have been used on this scale.
The power supply to the LHC’s straight sections requires smaller electrical feedboxes. There will be 44 feedboxes around the LHC ring, equipped with 1200 current leads carrying 120–13,000 A.
Meanwhile, on 5 September the 1000th cryomagnet (superconducting magnet system) was installed between Point 3 and Point 4. During the same week, the final cryomagnet for sector 8-1 was also installed. There are 1746 cryomagnets, of which 1232 are the famous dipoles.
