Fermilab History. Fermilab, originally named the National Accelerator Laboratory, was commissioned by the U.S. Atomic Energy Commission, under a bill signed by President Lyndon B. Johnson on November 21, 1967. Universities Research Association built the laboratory, and has operated the facility under those principles since its founding. On May 11, 1974, the laboratory was renamed in honor of 1938 Nobel Prize winner Enrico Fermi, one of the preeminent physicists of the atomic age.

Fermilab's 6,800-acre site was originally home to farmland, and to the village of Weston. Some of the original barns are still in use by the laboratory, for purposes ranging from storage to social events. A small burial ground, with headstones dating back to 1839, has been maintained in the northwest corner of the site. Robert Wilson was buried in the Pioneer Cemetery following his death on January 16, 2000 at the age of 85. Among Wilson's early imprints on the lab was the establishment of a herd of American bison, symbolizing the Fermilab's presence on the frontiers of high-energy physics, and the connection to its prairie origins. The herd stands today, and new calves are born every spring.

Director of Fermilab Pier J. Oddone (from 2005).

The Department of Energy promotes scientific and technological innovation to advance the national, economic and energy security of the United States. As part of the DOE strategic goals, Fermilab's mission is to advance the understanding of the fundamental nature of matter and energy: unlocking nature's deepest secrets, and learning how the universe is made and how it works. Fermilab's world-class scientific research facility allows qualified researchers from around the world to conduct fundamental research at the frontiers of high-energy physics and related disciplines.

Accelerators in Fermilab. Fermilab builds and operates the accelerators, detectors and other facilities that physicists need to carry out forefront research in high-energy physics. Fermilab is the largest high-energy physics laboratory in the United States, and is second in the world only to CERN, the European Laboratory for Particle Physics.

To explore the smallest particles, those inside an atom, physicists use the largest of scientific instruments, particle accelerators with a length measured in miles. These giant tools of particle physics can accelerate particles to very close to the speed of light.

All particle accelerators start from the principle that electrically charged objects exert a force on each other--opposite charges attract; like charges repel. If there are no other forces keeping the objects in place, the electric force will accelerate them. With an accelerator, physicists apply an electric force again and again to continually accelerate particles such as electrons, positrons, protons or antiprotons. In a circular accelerator, like Fermilab's Tevatron, the particles repeatedly pass the same force-exerting equipment and soon reach speeds close to the speed of light.

To make the simplest kind of accelerator, physicists use a battery and two parallel metal plates separated by a gap. We connect one plate to the positive battery terminal and the other to the negative terminal. The battery creates an electric field in the gap between the two plates. Positively charged particles that enter the gap near the positive plate experience a force and accelerate across the gap toward the negative plate, gaining an amount of energy that depends on the voltage of the battery. For a 10-volt battery, a proton gains 10 electron volts, or 10 eV, as it accelerates between the plates. Putting many power supplies in a row, physicists have accelerated particles to millions of electron volts (MeV).

At some point it is impractical to increase the voltage between the metal plates, as sparks will begin to fly across the gap. To accelerate particles to even higher energy, physicists use a large number of metal plates, all with a hole in the middle. Using alternating currents, the plates can be charged either positively or negatively. A positively charged particle, such as a proton, is drawn to the negatively charged plate in front of it, flying toward the hole. When the proton passes through the hole, the voltage of the plate is switched to a positive value, giving the proton an extra push. At the same time the next plate in front of the proton becomes negatively charged, attracting and accelerating the proton. Hence every gap between two plates provides energy to the proton as long as the voltage of the plates is switched whenever the proton crosses a hole. In high-energy accelerators, switching the voltage happens several billion times per second, or gigahertz frequencies.

Putting many plates in a row, physicists create linear accelerators, or linacs, that can accelerate charged particles to billions of electron volts (GeV). The more plates and gaps a linac has, the higher the energy it can give to a particle – and the longer the linac gets.

Rather than building longer and longer linacs, physicists are able to use magnets to guide charged particles in a circle. In doing so, physicists are able to send the particles again and again through the same set of plates, increasing the energy of the particles with each revolution.

As the particles gain energy, it is more and more difficult to keep them on the same circular path. The strength of the magnetic field must be increased. Ring-shaped particle accelerators operate the most powerful magnets in the world. The power of a ring-shaped proton accelerator is limited by its circumference and the strength of the magnets that are used. In the Tevatron, protons are accelerated to energy of almost 100 billion electron volts, or 1000 GeV. This is also called 1 TeV, which inspired the name Tevatron.

Fermilab's Tevatron is the world's highest-energy particle accelerator and collider. In the Tevatron, counter-rotating beams of protons and antiprotons produce collisions allowing scientists to examine the most basic building blocks of matter, and the forces acting on them. Particle physics research has grown into an international effort, with experiment collaborations numbering in the hundreds. Later this decade, the Large Hadron Collider at CERN will start producing collisions at seven times the energy of the Tevatron. More than 1,200 U.S. scientists are involved in the LHC and its experiments.

The Tevatron, four miles in circumference and originally named the Energy Doubler when it began operation in 1983, is the world's highest-energy particle accelerator. Its 1,000 superconducting magnets are cooled by liquid helium to -268 degrees C (-450 degrees F). Its low-temperature cooling system was the largest ever built when it was placed in operation in 1983. The American Society of Mechanical Engineers has designated the Tevatron cryogenic system an International Historic Mechanical Engineering Landmark.

Fermilab has added the two-mile Main Injector accelerator to increase the number of proton-antiproton collisions in the Tevatron, greatly enhancing the chances for important discoveries in Run II. The two apartment building-sized collider detectors, CDF and DZero, have undergone extensive upgrades during the nearly decade-long preparations for Run II.

Two major components of the Standard Model of Fundamental Particles and Forces were discovered at Fermilab: the bottom quark (May-June 1977) and the top quark (February 1995). In July 2000, Fermilab experimenters announced the first direct observation of the tau neutrino, the last fundamental particle to be observed. Filling the final slot in the Standard Model, the tau neutrino set the stage for new discoveries and new physics with the inauguration of Collider Run II of the Tevatron in March 2001. Dramatic discoveries in high-energy physics, including those at Fermilab, have revolutionized our understanding of the interactions of the particles and forces that determine the nature of matter in the universe. And there are more discoveries ahead, with Collider Run II of the Tevatron leading the way into the 21st century.

By Vasil Sidorov on February 2, 2009 from Fermilab  

E-mail: sidorovvasil@gmail.com

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