Knocking on Heaven's Door - Lisa Randall [78]
Following the CMS water trouble, the next crisis in the construction of the LHC machine itself struck in June 2004, when problems were discovered in the helium distribution line known as the QRL. The CERN engineers who investigated discovered the French firm that had taken on this construction project had replaced the material designated in the original design with what Lyn described as a “five-dollar spacer.” The replacement material cracked, allowing thermal contraction of the inner pipes. This faulty component wasn’t unique, and all the connections had to be checked.
By this time the cryogenic line had been partially installed and many other pieces had already been produced. To avoid blocking the supply chain and introducing further delays, the CERN engineers decided to repair what had already been produced while leaving industry to correct the problem before delivering the remaining parts. CERN’s factory operations and the need to move and reinstall large pieces of the machine cost the LHC a year delay. At least the delay was far less than the decade delay Lyn and others feared had lawyers been involved.
Without pipes and the cryogenic system, no one could install magnets. So 1,000 magnets sat around in the CERN parking lot. Even with the high-end BMWs and Mercedes that grace the lot at times, $1 billion worth of magnets probably exceeded the usual parking lot contents’ net worth. No one stole the valuable magnets, but a parking lot isn’t a great place to store technology, and further delays associated with restoring the magnets to their initial specification were inevitable.
In 2005, yet another near crisis occurred, having to do with the inner triplet constructed at Fermilab in the United States and in Japan. The inner triplet provides the final focusing of the proton beams before they collide. It combines three quadrupole magnets with cryogenic and power distribution—hence the name. This inner triplet failed during pressure tests. Although the failure was an embarrassment and an annoying delay, the engineers could fix it in the tunnel so the time cost wasn’t too severe in the end.
Overall, the year 2005 was more successful than its predecessor. The CMS cavern was inaugurated in February, though no horn graced the day. Another landmark event occurred in February—the lowering of the first cryodipole magnet. Magnet construction had been critical to the LHC enterprise. A close collaboration between CERN and commercial industry facilitated their timely and economical construction. Though designed at CERN, the magnets were produced at companies in France, Germany, and Italy. Initially, CERN engineers, physicists, and technicians placed an order for 30 dipoles in 2000, which they might then carefully examine to ensure quality and cost control before placing the final order for more than 1,000 magnets in 2002. CERN nonetheless maintained responsibility for procuring the main components and raw materials in order to maximize quality and uniformity and minimize cost. To do so, CERN moved 120,000 metric tons of material within Europe, employing an average of 10 big trucks a day for four years. And that was only one piece of the LHC effort.
After delivery, the magnets were all tested and carefully lowered through a vertical shaft into the tunnel near the Jura Mountains that overlook the CERN site. From there, a special vehicle transported them to their destination along the tunnel. Because these magnets are enormous and only a few centimeters separated the wall of the tunnel from the LHC installations, the vehicle was automatically guided by an optically detected line painted on the floor. The vehicle moved forward at a rate of only about a mile