BESSY
Encyclopedia
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
Storage Ring
Storage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...
Society for Synchrotron Radiation
Synchrotron radiation
The electromagnetic radiation emitted when charged particles are accelerated radially is called synchrotron radiation. It is produced in synchrotrons using bending magnets, undulators and/or wigglers...
), abbreviated BESSY, is a research establishment in the Adlershof
Adlershof
-External links:*...
district of Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
. Founded on 5 March 1979, it currently operates Germany's only 3rd generation synchrotron radiation facility
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronised with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...
, BESSY II. Originally part of the Gottfried Wilhelm Leibniz Scientific Community, BESSY now belongs to the Helmholtz-Zentrum Berlin
Helmholtz-Zentrum Berlin
The Helmholtz-Zentrum Berlin for Materials and Energy is a research centre and part of the Helmholtz Association of German Research Centres. The institute carries out research into the structure and dynamics of novel materials and also investigates solar cell technology.Several large scale...
(since 1 January 2009).
Owing to the radiometry
Radiometry
In optics, radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye...
lab of the PTB http://www.bessy.de/?idart=86&changelang=5, BESSY is the European calibration standard for electromagnetic radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
.
BESSY supplies synchrotron light and provides support for science and industry. There are institutional long-time users, like the Max-Planck-Society, the German Federal Institute for Materials Research and Testing
Bundesanstalt für Materialforschung und -prüfung
The Federal Institute for Materials Research and Testing or Bundesanstalt für Materialforschung und -prüfung is a German material research institute.-History:...
(BAM) and the national metrology
Metrology
Metrology is the science of measurement. Metrology includes all theoretical and practical aspects of measurement. The word comes from Greek μέτρον , "measure" + "λόγος" , amongst others meaning "speech, oration, discourse, quote, study, calculation, reason"...
institute of Germany (the PTB
Physikalisch-Technische Bundesanstalt
The Physikalisch-Technische Bundesanstalt is based in Braunschweig and Berlin. It is the national institute for natural and engineering sciences and the highest technical authority for metrology and physical safety engineering in Germany....
). Furthermore, research groups from other institutes or universities can apply for utilization (so called beam time) for certain projects.
BESSY I
This original synchrotron facility, costing the equivalent of 66.5 million EuroEuro
The euro is the official currency of the eurozone: 17 of the 27 member states of the European Union. It is also the currency used by the Institutions of the European Union. The eurozone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg,...
, became operational on 19 December 1981. It was situated in Wilmersdorf
Wilmersdorf
Wilmersdorf is an inner city locality of Berlin, formerly a borough by itself but since Berlin's 2001 administrative reform a part of the new borough of Charlottenburg-Wilmersdorf.-History:...
, then a borough of Berlin
Boroughs and localities of Berlin
Berlin is both a city and one of Germany’s federal states. It is made up of twelve boroughs , each with its own borough government, though all boroughs are subject to Berlin’s city and state government.-History:Each borough is made up of several officially recognized localities...
. The storage ring had a circumference of approx. 60 m. The circulating electrons that provided the radiation were in the energy range of 200 to 800 MeV (Vacuum Ultraviolet through Extreme Ultraviolet
Extreme ultraviolet
Extreme Ultraviolet radiation is high-energy ultraviolet radiation, generally defined to be electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 120 nm down to 10 nm, and therefore having photons with energies from 10 eV up to 124 eV...
).
After its decommissioning in 1999, the component parts of the BESSY I machine were donated to the SESAME project
International Centre for Synchrotron-Light for Experimental Science Applications in the Middle East
The International Centre for Synchrotron-Light for Experimental Science and Applications in the Middle East is an independent laboratory formally created under the auspices of UNESCO on 30 May 2002...
by the German Authorities and have consequently been shipped to Jordan
Jordan
Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...
.
Famous achievements of BESSY I were the calibration
Calibration
Calibration is a comparison between measurements – one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device....
of the spectrometers for the solar oberservatory probe SOHO
Solar and Heliospheric Observatory
The Solar and Heliospheric Observatory is a spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May...
as well as for the detectors for the Chandra X-ray Observatory
Chandra X-ray Observatory
The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. It was named in honor of Indian-American physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit.Chandra...
BESSY II
Groundbreaking for the new improved BESSY II synchrotron source in Adlershof took place on 4 July 1994, and the facility was inaugurated on 4 September 1998. The project cost was an equivalent of approximately 100 million Euros. The successor of BESSY I has a circumference of 240 m, providing 46 beam lines, and offers a multi-faceted mixture of experimental opportunities (undulatorUndulator
An undulator is an insertion device from high-energy physics and usually part of a largerinstallation, a synchrotron storage ring. It consists of a periodic structure of dipole magnets . The static magnetic field is alternating along the length of the undulator with a wavelength \lambda_u...
, wiggler
Wiggler (synchrotron)
A wiggler is an insertion device in a synchrotron. It is a series of magnets designed to periodically laterally deflect a beam of charged particles inside a storage ring of a synchrotron...
and dipole
Dipole magnet
A dipole magnet, in particle accelerators, is a magnet constructed to create a homogeneous magnetic field over some distance. Particle motion in that field will be circular in a plane perpendicular to the field and collinear to the direction of particle motion and free in the direction orthogonal...
sources) with excellent energy resolution. The combination of brightness
Brightness
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target...
and time resolution enables both femtosecond time and picometer spatial resolutions.
Electrons can be accelerated to an energy of up to 1.7 GeV (X-ray regime), and are subsequently injected into the storage ring. Synchrotron radiation emerges from the dipole magnets that bend the beam on a circular path, as well as from undulators and wigglers. The total power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
input during regular operation is 2.7 MW
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
.
BESSY II can be run in different modes, according to the time-distance between the electron wave packet
Wave packet
In physics, a wave packet is a short "burst" or "envelope" of wave action that travels as a unit. A wave packet can be analyzed into, or can be synthesized from, an infinite set of component sinusoidal waves of different wavenumbers, with phases and amplitudes such that they interfere...
s that circulate in the storage ring:
- multi bunch: This is the most common mode. Around 350 equal packets are in the ring, with a time-distance of 2 nsNanosecondA nanosecond is one billionth of a second . One nanosecond is to one second as one second is to 31.7 years.The word nanosecond is formed by the prefix nano and the unit second. Its symbol is ns....
- single bunch: This mode is in effect for two weeks each half-year. Only one single electron packet is in the ring, thus enabling the users to measure with the highest possible time resolution. Two light pulses arrive with a gap of 800 ns and can therefore be easily separated.
- low alpha: This mode exists in single and multi bunch sub-modes. The spatial resolution of the electron packet is higher (it is comprimated), which leads to a higher rate of Terahertz radiation and shorter light pulses.
Experiments at BESSY II are in the fields of X-ray absorption spectroscopy, Photoemission spectroscopy
Photoemission spectroscopy
Photoemission spectroscopy , also known as photoelectron spectroscopy, refers to energy measurement of electrons emitted from solids, gases or liquids by the photoelectric effect, in order to determine the binding energies of electrons in a substance...
, Photoemission electron microscopy, X-ray microscopy
X-ray microscope
An X-ray microscope uses electromagnetic radiation in the soft X-ray band to produce images of very small objects.Unlike visible light, X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore the basic process of an X-ray microscope is to expose film or use a...
, femtosecond slicing
Laser cutting
Laser cutting is a technology that uses a laser to cut materials, and is typically used for industrial manufacturing applications, but is also starting to be used by schools, small businesses and hobbyists. Laser cutting works by directing the output of a high-power laser, by computer, at the...
, X-ray lithography
X-ray lithography
300px|thumbX-ray lithography, is a process used in electronic industry to selectively remove parts of a thin film. It uses X-rays to transfer a geometric pattern from a mask to a light-sensitive chemical photoresist, or simply "resist," on the substrate...
, and protein structure analysis
X-ray crystallography
X-ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and causes the beam of light to spread into many specific directions. From the angles and intensities of these diffracted beams, a crystallographer can produce a...
.
BESSY maintains a close co-operation with other synchrotron sources in the world, most notably with DESY
DESY
The DESY is the biggest German research center for particle physics, with sites in Hamburg and Zeuthen....
in Hamburg
Hamburg
-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...
.
Further Facilities
- In September 2008, the Metrology Light Source (MLS) http://www.ptb.de/mls/ was inaugurated. This facility in close proximity to BESSY II is run by PTB and provides synchrotron radiation in the energy range of far infrared and Terahertz radiationTerahertz radiationIn physics, terahertz radiation refers to electromagnetic waves propagating at frequencies in the terahertz range. It is synonymously termed submillimeter radiation, terahertz waves, terahertz light, T-rays, T-waves, T-light, T-lux, THz...
. The two facilities complement one another.
- In 2000, the construction of a free electron laserFree electron laserA free-electron laser, or FEL, is a laser that shares the same optical properties as conventional lasers such as emitting a beam consisting of coherent electromagnetic radiation which can reach high power, but which uses some very different operating principles to form the beam...
on the BESSY site was planned, which was dubbed BESSY-FEL http://www.bessy.de/cms.php?idcat=31&idart=421&changelang=5. It was supposed to create extremely short and bright ultraviolet and X-ray pulses. In the autumn of 2008, the project was cut, and only an extension to the FLASHFLASHFLASH, acronym of Free Electron LASer in Hamburg, a particle accelerator-based soft x-ray laser located at the DESY accelerator facilities in Hamburg, Germany. It can generate very powerful, ultrashort pulses of coherent radiation in the energy range 10 eV to 200 eV...
free electron laser in Hamburg is now to be built.