An electrical device that generates charged particles, such as electrons, protons and ions, at high energy. So-called "nuclear accelerators" are used to split the atom for scientific research, but most particle accelerators are built for more practical applications. They are used to manufacture myriad products including semiconductors. They are also used as X-ray machines for cancer treatment and for detecting weaknesses in materials.
The Large Hadron Collider (LHC) is being built at CERN, the European laboratory for nuclear research. Costing around $8 billion and expected to roll out in 2008, it will be the largest particle accelerator in the world for nuclear research. While making 17-mile laps at nearly the speed of light, protons will be made to collide into other particles 10 million times per second. The main purpose is to find the Higgs boson, considered by some scientists to be the fundamental element of matter and often called the "God Particle."
In order to process the data coming from the accelerator, a huge computing grid that uses resources from more than 150 institutions around the world, began testing in 2006. See peer-to-peer computing.
Looking like science fiction, this accelerator is used for a very mundane application. Standing about 10 feet tall, it radiates plastic heat shrinkable tubing to give it a memory. The tubing is then moved to a machine that increases its diameter. Used to protect wires and connections in electronic and electrical circuits, when the tubing is placed over the wires and heated, it returns to its original size because of the radiation.
A machine (sometimes called an “atom smasher”), often very large, that brings elementary particles (usually either protons or electrons) to a very high speed and then allows them to collide with a target. From the resulting behavior of the particles and the target, scientists deduce the structure of the particles.
Almost all of our knowledge of the nucleus and of elementary particles depends on experiments using particle accelerators.
Any of several machines, such as the cyclotron and linear accelerator, that increase the speed and energy of protons, electrons, or other atomic particles, and direct them at atomic nuclei or other particles to cause high-energy collisions. Such collisions produce other particles, whose paths are tracked and analyzed. Particle accelerators are used to study the nature of the atomic nucleus, subatomic particles, and the forces relating them, and to create radioactive isotopes.
A Closer Look The particle accelerators used by physicists are not as remote from our everyday experience as one might imagine. The cathode ray tubes of televisions and computer monitors, commonly known as picture tubes, are in fact small, low-energy particle accelerators, creating beams of electrons guided and focused by magnets that hit a phosphorescent screen to produce light. The electrons, having an electric charge, are accelerated by an electric field produced by a voltage difference of about a thousand volts. Accelerating electrons to higher velocities, using voltages in the tens of thousands, allows higher-energy radiation to be released; the x-ray tubes used in diagnostic imaging operate on this principle. Today's high-energy particle accelerators, such as synchrocyclotrons and synchrotrons, accelerate charged particles such as electrons and protons using the same basic principles as ordinary picture tubes, but to much higher velocities. These machines are ring-shaped, often extremely large (some more than ten miles in length), and they accelerate particles to velocities so close to the speed of light that the effects of relativity, such as time dilation and increased particle mass, become important factors. For theoretical physicists, these high speeds are generated to smash the particles against other particles as hard as possible—just like smashing a rock against a wall—just to see what happens. For example, particles once thought to be elementary, like protons, have been shown to consist of yet smaller constituents (quarks, in this case) by observing the scattering patterns that follow certain collisions. A large variety of exotic particles have been created as well in the shower of particles that result from some collisions, and explaining their existence and behavior has deepened theories of fundamental physics. From the explosive aftermath of these artificial high-energy particle collisions, robust theories of the most fundamental constituents of the natural world are being developed.