Knocking on Heaven's Door - Lisa Randall [66]
The collisions we’ll study at the LHC are akin to those that took place in the first trillionth of a millisecond after the Big Bang. They will teach us about small distances and about the nature of matter and forces at this very early time. You might think of the Large Hadron Collider as a super-microscope that allows us to study particles and forces at incredibly small sizes—on the order of a tenth of a thousandth of a trillionth of a millimeter.
The LHC achieves these tiny probes by creating higher energy particle collisions than ever before achieved on Earth—up to seven times the energy of the highest existing collider, the Tevatron in Batavia, Illinois. As explained in Chapter 6, quantum mechanics and its use of waves tells us these energies are essential for investigating such small distances. And—along with the increase in energy—the intensity will be 50 times higher than at the Tevatron, making discovering the rare events that could reveal nature’s inner workings that much more likely.
Despite my resistance to hyperbole, the LHC belongs to a world that can only be described with superlatives. It is not merely large: the LHC is the biggest machine ever built. It is not merely cold: the 1.9 kelvin (1.9 degrees Celsius above absolute zero) temperature necessary for the LHC’s superconducting magnets to operate is the coldest extended region that we know of in the universe—even colder than outer space. The magnetic field is not merely big: the superconducting dipole magnets generating a magnetic field more than 100,000 times stronger than the Earth’s are the strongest magnets in industrial production ever made.
And the extremes don’t end there. The vacuum inside the proton-containing tubes, a 10 trillionth of an atmosphere, is the most complete vacuum over the largest region ever produced. The energy of the collisions are the highest ever generated on Earth, allowing us to study the interactions that occurred in the early universe the furthest back in time.
The LHC also stores huge amounts of energy. The magnetic field itself stores an amount equivalent to a couple of tons of TNT, while the beams store about a tenth of that. That energy is stored in one-billionth of a gram of matter, a mere submicroscopic speck of material under ordinary circumstances. When the machine is done with the beam, this enormously concentrated energy is dumped into a cylinder of graphite composite eight meters long and one meter in diameter, which is encased in 1,000 tons of concrete.
The extremes achieved at the LHC push technology to its limits. They don’t come cheaply and the superlatives extend to cost. The LHC’s $9 billion price tag also makes it the most expensive machine ever built. CERN paid about two-thirds of the cost of the machine, with CERN’s 20 member countries contributing to the CERN budget according to their means, ranging from 20 percent from Germany to 0.2 percent from Bulgaria. The remainder was paid for by nonmember states, including the United States, Japan, and Canada. CERN contributes 20 percent to the experiments themselves, which are funded by international collaborations. As of 2008, when the machine was essentially built, the United States had more than 1,000 scientists working on CMS and ATLAS and had contributed $531 million toward the LHC enterprise.
THE BEGINNING OF THE LHC
CERN, which houses the LHC, is a research facility, with many programs operating simultaneously. However, CERN’s resources are generally concentrated in a single flagship program.