Storage ring

A storage ring is a special form of a synchrotron particle accelerator, specializing in the collection and long maintenance of a high beam current. It consists of a ring-shaped vacuum vessel are maintained in the high-energy charged particles by magnets on a closed orbit.

The filling of a storage ring is usually a separate particle accelerator; however, a synchrotron also work even as a storage ring by the acceleration voltage is low or off and the field of the bending magnets is kept constant. Some plant can therefore equally well be called a synchrotron as a storage ring.

Most of the accelerator many bunches are accumulated (hence the name "Memory" ), so that the intensity in the storage ring is much higher than in the accelerator beam in the storage ring. In large plants, so beam currents generated by several amperes. To achieve a long residence time of the beam in the storage ring of sometimes many hours, an extremely good vacuum is necessary because collisions with the residual gas reduce the beam strength and also affect the beam quality. An exiting beam from the ring to experimental purposes is either not provided or is of secondary importance. There are storage rings for electrons and a large variety of ions, from protons and anti- protons to heavy ions such as gold and lead.

Generation of synchrotron

Electron storage rings are often operated primarily for the purpose of generation of synchrotron radiation. For increasing the intensity of the synchrotron radiation special components to be installed, the so-called wiggler and undulator, through which the electrons are placed on the straight line in a shaft and thus to the increased delivery of the radiation. In the acceleration sections, the radiation losses are compensated.


A special form of storage rings are the so-called Collider (English collide: collide ), which are composed mostly of two rings with opposite direction of rotation. The particles are placed in one or more intersection points for collision. In this way, unlike the bombardment of a stationary target, the total kinetic energy is converted into mass of new particles, because there is no kinetic energy for a further movement of the center of gravity of the particle system is required (see Colliding Beam Experiment).

It also exists in the use of high-energy light particles like electrons to the problem of all circular accelerators, the energy loss due to synchrotron radiation. Therefore, new concepts for high energy electron collider see two oppositely directed linear accelerator before such as when being planned International Linear Collider.

Physical Basics

Due to the Lorentz force, a moving at the speed charged particle of mass m and charge q in a magnetic field is forced into a circular orbit of radius r. Substituting the Lorentz force and centripetal force equal, you can resolve the resulting equation with respect to and determine the diameter of the circle, move on the the particles at a given magnetic field. Also, by electric fields particles can be deflected. In a storage ring fast electrically charged particles (eg electrons) held by magnetic fields on a closed path and then saved.

Storage ring locations

Storage rings can be found

  • At CERN near Geneva LHC - Large Hadron Collider ( range: 27 km, planned mass energy: 14 TeV, commissioning November 2009)
  • LEP - Large Electron Positron Storage Ring ( size: 27 km, reached the highest center of mass energy 209 GeV, operating from 1989 to 2000 )
  • Intersecting Storage Rings ( circumference approx 940 m, center of mass energy: 56 GeV, operating from 1971 to 1984 )
  • BESSY II at the Helmholtz Centre Berlin for Materials and Energy ( HZB) ( length 240 m, energy 1.7 GeV )
  • MLS (Willy Wien Laboratory ) of the Physikalisch -Technische Bundesanstalt ( PTB) ( 48 m circumference, energy 200-600 MeV)
  • ANKA - Angströmquelle Karlsruhe (circumference 100 m, energy 2.5 GeV )
  • DELTA - Dortmund electron storage ring facility ( 115.2 m)
  • DORIS - Double Ring Store ( range: 300 m, energy 4.6 GeV )
  • PETRA - Positron Electron Tandem Ring Accelerator ( range: 2.3 km, maximum center of mass energy 47 GeV, operating as a collider from 1978 to 1986, from 2009 working as a synchrotron radiation source)
  • HERA - Hadron Electron Ring Accelerator (circumference: 6,3 km, running from 1991 to 2007 )
  • Tevatron - proton -antiproton accelerator (circumference: 6,3 km, center of mass energy 1.96 TeV, operating since 1983)
  • ESR - experimental storage ring
  • TSR
  • PEP - II