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Encyclopedia > Synchrotron radiation
General Electric synchrotron accelerator built in 1946, the origin of the discovery of synchrotron radiation.
General Electric synchrotron accelerator built in 1946, the origin of the discovery of synchrotron radiation.
This article concerns the physical phenomenon of synchrotron radiation. For details on the production of this radiation in laboratories, see synchrotron. For applications, see synchrotron light.

Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i.e., moving near the speed of light) charged particles through magnetic fields. This may be achieved artificially by storage rings in a synchrotron, or naturally by fast moving electrons moving through magnetic fields in space. The radiation typically includes radio waves, infrared light, visible light, ultraviolet light, and x-rays. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Synchrotrons are now mostly used for producing monochromatic high intensity X-ray beams; here, the synchrotron is the circular track, off which the beamlines branch. ... Synchrotrons are now mostly used for producing monochromatic high intensity X-ray beams; here, the synchrotron is the circular track, off which the beamlines branch. ... Synchrotron radiation emerging from a beam port. ... It has been suggested that this article or section be merged with light. ... Cyclotron radiation is a type of bremsstrahlung (braking) radiation. ... In physics, ultrarelativistic is said of a particle when its speed is very close to the speed of light , such that its total energy is almost completely due to its momentum (), and thus can be approximated by . ... A line showing the speed of light on a scale model of Earth and the Moon The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness. It is the speed of all electromagnetic radiation... Synchrotrons are now mostly used for producing monochromatic high intensity X-ray beams; here, the synchrotron is the circular track, off which the beamlines branch. ... It has been suggested that this article or section be merged with radio frequency. ... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... UV redirects here. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...


The radiation was named after its discovery in a General Electric synchrotron accelerator built in 1946 and announced in May 1947 by Frank Elder, Anatole Gurewitsch, Robert Langmuir, and Herb Pollock in a letter entitled "Radiation from Electrons in a Synchrotron"[1]. Pollock recounts:

"On April 24, Langmuir and I were running the machine and as usual were trying to push the electron gun and its associated pulse transformer to the limit. Some intermittent sparking had occurred and we asked the technician to observe with a mirror around the protective concrete wall. He immediately signaled to turn off the synchrotron as "he saw an arc in the tube." The vacuum was still excellent, so Langmuir and I came to the end of the wall and observed. At first we thought it might be due to Cherenkov radiation, but it soon became clearer that we were seeing Ivanenko and Pomeranchuk radiation."[2]

Contents

Cherenkov radiation glowing in the core of a TRIGA reactor Cherenkov radiation (also spelled Cerenkov or sometimes Čerenkov) is electromagnetic radiation emitted when a charged particle passes through an insulator at a speed greater than the speed of light in that medium. ... Dmitri Ivanenko (Russian: Дмитрий Дмитриевич Иваненко) (1904 - 1994) was a Professor of Moscow State University (since 1943), made the great contribution to the physical science (especialy, to gravitational physics) of the twentieth century. ... Isaak Yakovlevich Pomeranchuk (1913-1966) was a Polish-born Ukrainian physicist. ...

Synchrotron radiation from storage rings

Synchrotron radiation is characterized by:

  • High brightness and high intensity, many orders of magnitude more than with X-rays produced in conventional X-ray tubes
  • High brilliance, exceeding other natural and artificial light sources by many orders of magnitude: 3rd generation sources typically have a brilliance larger than 1018 photons/s/mm2/mrad2/0.1%BW, where 0.1%BW denotes a bandwidth 10-3w centered around the frequency w.
  • High collimation, i.e. small angular divergence of the beam
  • Low emittance, i.e. the product of source cross section and solid angle of emission is small
  • Widely tunable in energy/wavelength by monochromatization (sub eV up to the MeV range)
  • High level of polarization (linear or elliptical)
  • Pulsed light emission (pulse durations at or below one nanosecond, or a billionth of a second);

Electrons are accelerated to high speeds in several stages to achieve a final energy that is typically in the GeV range. The electrons are stored in an ultrahigh vacuum ring on a closed loop and thus circle the ring a vast number of times. The electrons are forced to travel in a closed loop by strong magnetic fields. The magnets also need to repeatedly recompress the Coulomb-exploding space charge electron bunches. The change of direction is a form of acceleration and thus the electrons emit radiation at GeV frequencies. This is similar to a radio antenna, but with the difference that the relativistic speed changes the observed frequency due to the Doppler effect by a factor γ. Relativistic Lorentz contraction bumps the frequency by another factor of γ, thus multiplying the GeV frequency of the resonant cavity that accelerates the electrons into the X-ray range. Another dramatic effect of relativity is that the radiation pattern is also distorted from the isotropic dipole pattern expected from non-relativistic theory into an extremely forward-pointing cone of radiation. This makes synchrotron radiation sources the brightest known sources of X-rays. The planar acceleration geometry makes the radiation linearly polarized when observed in the orbital plane, and circularly polarized when observed at a small angle to that plane. High Energy X-rays or HEX-rays are very hard X-rays, with 80 keV - 1000 keV typically one order of magnitude higher in energy than conventional X-rays. ... This page is a list of sources of light. ... Look up second in Wiktionary, the free dictionary. ...


The advantages of using synchrotron radiation for spectroscopy and diffraction have been realized by an ever-growing scientific community, beginning in the 1960s and 1970s. In the beginning, storage rings were built for particle physics and synchrotron radiation was used in "parasitic mode" when bending magnet radiation had to be extracted by drilling extra holes.


As the application of synchrotron radiation became more intense and promising, devices that enhanced the intensity of synchrotron radiation were built into existing rings. Third-generation synchrotron radiation sources were conceived and optimized from the outset to produce bright X-rays.


Nowadays, fourth-generation sources that will include different concepts for producing ultrabright, pulsed time-structured X-rays for extremely demanding and also probably yet-to-be-conceived experiments are under consideration.


As mentioned above, bending electromagnets are usually used to generate the radiation, but to generate stronger radiation, another kind of device, called an insertion device, is sometimes employed. Current third-generation synchrotron radiation sources are typically heavily based upon these insertion devices, when straight sections in the storage ring are used for inserting periodic magnetic structures (composed of many magnets that have a special repeating row of N and S poles) that force the electrons into a sinusoidal path or helical path. Thus, instead of a single bend, many tens or hundreds of "wiggles" at precisely calculated positions add up or multiply the total intensity that is seen at the end of the straight section. Thus these devices are called wigglers or undulators. The main difference between an undulator and a wiggler is the intensity of their magnetic field and the amplitude of the deviation from the straight line path of the electrons. An undulator is a device from high-energy physics and usually part of a larger installation, a synchrotron. ... An wiggler is an insertion device for a synchrotron. ...


There are openings in the storage ring to let the radiation exit and follow a beam line into the experimenters' vacuum chamber. A great number of such beamlines can emerge from modern third-generation synchrotron radiation sources.


Synchrotron radiation is used in particle accelerators in radiation damping, a method of reducing beam emittance. A particle accelerator uses electric fields to propel charged particles to great energies. ... Radiation damping in accelerator physics is a way of reducing the beam emittance of a beam of accelerated charged particles. ... The beam emittance of a particle accelerator is the amount of spread of the beam as it travels. ...


Synchrotron radiation in astronomy

M87's Energetic Jet. The glow is caused by synchrotron radiation, high-energy electrons spiraling along magnetic field lines, and was first detected in 1956 by Geoffrey R. Burbidge in M87 confirming a prediction by Hannes Alfvén and Nicolai Herlofson in 1950, and Iosif S. Shklovskii in 1953.
M87's Energetic Jet. The glow is caused by synchrotron radiation, high-energy electrons spiraling along magnetic field lines, and was first detected in 1956 by Geoffrey R. Burbidge in M87 confirming a prediction by Hannes Alfvén and Nicolai Herlofson in 1950, and Iosif S. Shklovskii in 1953.

Synchrotron radiation is also generated by astronomical structures and motions, typically where relativistic electrons spiral (and hence change velocity) through magnetic fields. Two of its characteristics include (1) Non-thermal radiation (2) Polarization.[3] Download high resolution version (611x638, 41 KB)from http://hubblesite. ... Download high resolution version (611x638, 41 KB)from http://hubblesite. ... The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... Geoffrey Ronald Burbidge (born September 24, 1925) is a British-American physics professor in the University of California, San Diego. ... Hannes Alfvén (1908-1995), winning the Nobel Prize for his work on magnetohydrodynamics [1]. Hannes Olof Gösta Alfvén (May 30, 1908; Norrköping, Sweden – April 2, 1995; Djursholm, Sweden) was a Swedish plasma physicist who won the 1970 Nobel Prize in Physics for his work developing the... Iosif Samuilovich Shklovsky (Ио́сиф Самуи́лович Шкло́вский) (July 1, 1916 – March 3, 1985) was a Soviet/Russian astronomer and astrophysicist. ... In electrodynamics, polarization (also spelled polarisation) is the property of electromagnetic waves, such as light, that describes the direction of their transverse electric field. ...


History

It was first detected, in a jet emitted by M87, in 1956 by Geoffrey R. Burbidge [4], who saw it as confirmation of a prediction by Iosif S. Shklovskii in 1953, but it had been predicted several years earlier by Hannes Alfvén and Nicolai Herlofson [5] in 1950. The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... Geoffrey Ronald Burbidge (born September 24, 1925) is a British-American physics professor in the University of California, San Diego. ... Iosif Samuilovich Shklovsky (Ио́сиф Самуи́лович Шкло́вский) (July 1, 1916 – March 3, 1985) was a Soviet/Russian astronomer and astrophysicist. ... Hannes Alfvén (1908-1995), winning the Nobel Prize for his work on magnetohydrodynamics [1]. Hannes Olof Gösta Alfvén (May 30, 1908; Norrköping, Sweden – April 2, 1995; Djursholm, Sweden) was a Swedish plasma physicist who won the 1970 Nobel Prize in Physics for his work developing the...


T. K. Breus noted that questions of priority on the history of astrophysical synchrotron radiation is quite complicated, writing:

"In particular, the Russian physicist V.L. Ginsburg broke his relationships with I.S. Shklovsky and did not speak with him for 18 years. In the West, Thomas Gold and Sir Fred Hoyle were in dispute with H. Alfven and N. Herlofson, while K.O. Kiepenheuer and G. Hutchinson were ignored by them."[6]

Supermassive black holes have been suggested for producing synchrotron radiation, by gravitationally accelerating ions through magnetic fields. Vitaly Lazarevich Ginzburg (Russian: ; born October 4, 1916 in Moscow) is a Soviet/Russian theoretical physicist and astrophysicist, a member of the Academy of Sciences of the former Soviet Union, and the successor to Igor Tamm as head of the Academys physics institute (FIAN). ... Iosif Samuilovich Shklovsky (Ио́сиф Самуи́лович Шкло́вский) (July 1, 1916 – March 3, 1985) was a Soviet/Russian astronomer and astrophysicist. ... Thomas Gold (May 22, 1920 – June 22, 2004) was an Austrian astrophysicist, a professor of astronomy at Cornell University, and a member of the US National Academy of Sciences. ... Sir Frederick Hoyle (born on June 24, 1915 in Gilstead, Yorkshire, England – August 20, 2001 in Bournemouth, England)[1] was a British astronomer, notable for a number of his theories that run counter to current astronomical opinion, and a writer of science fiction, including a number of books co-authored... Hannes Alfvén (1908-1995), winning the Nobel Prize for his work on magnetohydrodynamics [1]. Hannes Olof Gösta Alfvén (May 30, 1908; Norrköping, Sweden – April 2, 1995; Djursholm, Sweden) was a Swedish plasma physicist who won the 1970 Nobel Prize in Physics for his work developing the... Top: artists conception of a supermassive black hole drawing material from a nearby star. ...


Footnotes

  1. ^ Elder, F. R.; Gurewitsch, A. M.; Langmuir, R. V.; Pollock, H. C., "Radiation from Electrons in a Synchrotron" (1947) Physical Review, vol. 71, Issue 11, pp. 829-830
  2. ^ Handbook on Synchrotron Radiation, Volume 1a, Ernst-Eckhard Koch, Ed., North Holland, 1983, reprinted at "Synchrotron Radiation Turns the Big Five-O"
  3. ^ Vladimir A. Bordovitsyn, "Synchrotron Radiation in Astrophysics" (1999) Synchrotron Radiation Theory and Its Development, ISBN 981-02-3156-3
  4. ^ Burbidge, G. R. "On Synchrotron Radiation from Messier 87. Astrophysical Journal, vol. 124, p.416"
  5. ^ Alfvén, H.; Herlofson, N. "Cosmic Radiation and Radio Stars" Physical Review (1950), vol. 78, Issue 5, pp. 616-616
  6. ^ Breus, T. K., "Istoriya prioritetov sinkhrotronnoj kontseptsii v astronomii %t (Historical problems of the priority questions of the synchrotron concept in astrophysics)" (2001) in Istoriko-Astronomicheskie Issledovaniya, Vyp. 26, p. 88 - 97, 262 (2001)

See also

Synchrotrons are now mostly used for producing monochromatic high intensity X-ray beams; here, the synchrotron is the circular track, off which the beamlines branch. ... Synchrotron radiation emerging from a beam port. ... In the physics of electromagnetism, the radiation reaction is the recoil force felt by a charged object that is emitting electromagnetic radiation. ...

External links


  Results from FactBites:
 
Synchrotron radiation - Wikipedia, the free encyclopedia (932 words)
Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i.e., moving near the speed of light) electrons through magnetic fields.
Current third generation synchrotron radiation sources typically are heavily based upon these insertion devices, when straight sections in the storage ring are used for inserting periodic magnetic structures (composed of many magnets that have a special repeating row of N and S poles) that force the electrons on a sinusoidal path or helical path.
Synchrotron radiation is used in particle accelerators in radiation damping, a method of reducing beam emittance.
Synchrotron - Wikipedia, the free encyclopedia (1171 words)
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field (to turn the particles so they circulate) and the electric field (to accelerate the particles) are carefully synchronized with the travelling particle beam.
Synchrotron radiation is useful for a wide range of applications and many synchrotrons have been built especially to produce synchrotron light.
Synchrotrons which are useful for cutting edge research are large machines, costing tens or hundreds of millions of dollars to construct, and each beamline (there may be 20 to 50 at a large synchrotron) costs another two or three million dollars on average.
  More results at FactBites »

 
 

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