The Chasman–Green lattice, also known as a double bend achromat lattice (DBA lattice), is a special periodic arrangement of magnets designed by

Renate Chasman Renate Wiener Chasman (January 10, 1932 – October 17, 1977) was a physicist. She was born Renate Wiener to German Jewish parents in Berlin. Her father, Hans Wiener, was a founder of the Social Democratic Party of Germany. In 1938, the Wiener f ...

and

George Kenneth Green George Kenneth Green (1911 – August 15, 1977) was an American accelerator physicist. Green studied at the University of California, Berkeley, where he belonged to the group of Ernest Lawrence. Later, he worked at Brookhaven National Laboratory ...

Brookhaven National Laboratory Brookhaven National Laboratory (BNL) is a United States Department of Energy national laboratories, United States Department of Energy national laboratory located in Upton, New York, a hamlet of the Brookhaven, New York, Town of Brookhaven. It w ...

in the mid-1970s for

synchrotron 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 strength of the magnetic field which bends the particle beam i ...

s. This lattice provides optimized bending and focusing of electrons in

storage ring A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating, typically for many hours. Storage of a particular particle depends upon the mass, momentum, and usually the charge o ...

s designed for

synchrotron light source A synchrotron light source is a source of electromagnetic radiation (EM) usually produced by a storage ring, for scientific and technical purposes. First observed in synchrotrons, synchrotron light is now produced by storage rings and othe ...

s. An electron storage ring constructed with a Chasman–Green lattice has the important property that the circulating

electron beam Since the mid-20th century, electron-beam technology has provided the basis for a variety of novel and specialized applications in semiconductor manufacturing, microelectromechanical systems, nanoelectromechanical systems, and microscopy. Mechani ...

s have very low emittance, which results in the emission of

synchrotron light Synchrotron radiation (also known as magnetobremsstrahlung) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity (). It is produced artificially in some types ...

of exceptional brightness. For this reason it is the lattice of choice for most of the premier synchrotron light source facilities worldwide. Each period of the Chasman–Green lattice contains a focusing

quadrupole magnet Quadrupole magnets, abbreviated as Q-magnets, consist of groups of four magnets laid out so that in the planar multipole expansion of the field, the dipole terms cancel and where the lowest significant terms in the field equations are quadrupole. ...

symmetrically located between a pair of identical

dipole magnet A dipole magnet is the simplest type of magnet. It has two poles, one north and one south. Its magnetic field lines form simple closed loops which emerge from the north pole, re-enter at the south pole, then pass through the body of the magnet. ...

s, which transports incident electrons through a bending arc to an exit path that is independent of the electron energy.

References

Accelerator physics {{accelerator-stub