The first synchrotron to use the "racetrack" design with straight sections, a 300 MeV electron synchrotron at University of Michigan in 1949, designed by Dick Crane.
A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The magnetic field which bends the particle beam into its closed path increases with time during the accelerating process, being synchronized to the increasing kinetic energy of the particles (see image). The synchrotron is one of the first accelerator concepts to enable the construction of large-scale facilities, since bending, beam focusing and acceleration can be separated into different components. The most powerful modern particle accelerators use versions of the synchrotron design. The largest synchrotron-type accelerator, also the largest particle accelerator in the world, is the 27-kilometre-circumference (17 mi) Large Hadron Collider (LHC) near Geneva, Switzerland, built in 2008 by the European Organization for Nuclear Research (CERN). It can accelerate beams of protons to an energy of 6.5 teraelectronvolts (TeV).
Several specialized types of synchrotron machines are used today:
A storage ring is a special type of synchrotron in which the kinetic energy of the particles is kept constant.
A synchrotron light source is a combination of different electron accelerator types, including a storage ring in which the desired electromagnetic radiation is generated. This radiation is then used in experimental stations located on different beamlines. In addition to the storage ring, a synchrotron light source usually contains a linear accelerator (linac) and another synchrotron which is sometimes called booster in this context. The linac and the booster are used to successively accelerate the electrons to their final energy before they are magnetically "kicked" into the storage ring. Synchrotron light sources in their entirety are sometimes called "synchrotrons", although this is technically incorrect.
A cyclic collider is also a combination of different accelerator types, including two intersecting storage rings and the respective pre-accelerators.