German electron synchrotron
The German Electron Synchrotron DESY in the Helmholtz Association is a research center for basic scientific research based in Hamburg and Zeuthen .
DESY has four main research areas:
- Development, construction and operation of particle accelerators
- Particle physics
- Astroparticle physics
- Research with photons .
The DESY research center is a foundation under civil law and is financed by public funds. The foundation “Deutsches Electron Synchrotron DESY” was founded on December 18, 1959 in Hamburg by a state treaty signed by Siegfried Balke - the then Federal Minister for Nuclear Energy and Water Management - and the Hamburg Mayor Max Brauer . The DESY Foundation is a member of the Helmholtz Association of German Research Centers .
tasks
DESY's task is basic scientific research . The research center focuses on three main areas in Hamburg:
- Development, construction and operation of particle accelerators;
- Investigation of the fundamental properties of matter and forces in the context of particle physics or high energy physics ;
- Research with photons , d. H. Synchrotron radiation and free-electron laser in (among others) physics , chemistry , biology , geology and medicine .
At the Zeuthen location there is another research focus:
- Astroparticle physics by applying the methods of particle physics in the context of astrophysics.
DESY makes accelerator facilities available to science that are used nationally and internationally by various institutes and universities.
Locations
DESY has two locations. The larger location is in Hamburg-Bahrenfeld near the Altonaer Volkspark . On January 1, 1992, DESY was expanded to include a second location in Zeuthen (until 1991 Institute for High Energy Physics ), southeast of Berlin .
Budget and Financing
The research center has an annual budget of around € 230 million. Approx. € 211 million of this is attributable to the Hamburg location, the remaining approx. € 19 million to the Zeuthen location. 90% of the funding is provided by the Federal Ministry of Education and Research and 10% by the city of Hamburg or the state of Brandenburg .
Employees and training
DESY employs a total of around 2300 people. Around 2100 employees are employed at the Hamburg location and around 200 at the Zeuthen location. Included in these numbers are over 100 trainees in industrial and technical professions as well as over 100 diploma students, more than 350 doctoral students and approx. 300 young scientists who are supervised by DESY.
International cooperation
Over 3000 scientists from over 45 nations use the DESY facilities.
The HERA particle accelerator was the first internationally financed large-scale project in particle research. Previously, the construction of accelerators had always been 100% financed by the country in which they were located, and the national and foreign institutes involved only took part in the experiments they used. However, the desire for the HERA accelerator facility was so great that international institutions agreed to contribute to the construction of the particle accelerator. A total of twelve countries with more than 45 institutes participated in the construction of the facility (approx. 22% of the HERA construction costs of approx. € 700 million were taken over by foreign institutions).
Following the example of HERA, many major scientific projects were carried out jointly by several countries in the following years. The model has now established itself, and international cooperation is widespread even during the construction of the plants.
Particle accelerators and facilities
The accelerators from DESY were created one after the other with the demand of the particle physicists for ever higher particle energies in order to improve the investigation of particle structures. With the construction of newer accelerators, the older accelerators were converted into pre-accelerators and sources for synchrotron radiation .
The development of the various systems is treated chronologically below:
DESY
Construction of the first particle accelerator DESY ( D eutsches E lektronen - Sy nchrotron ), who gave the research center its name, began in 1960. The ring accelerator at the time was the world's largest facility of its kind and could electrons to 7.4 GeV accelerate. On January 1, 1964, electrons were accelerated in the synchrotron for the first time and research on elementary particles began. Between 1965 and 1976 the facility was used for particle physics research.
DESY first attracted international attention in 1966 with its contribution to testing quantum electrodynamics . The results confirmed this theory. In the following decade, DESY established itself as a competence center for the development and operation of particle accelerator systems.
Research with photons began at the research center in 1964 by using synchrotron radiation, which occurs as a side effect when electrons are accelerated in the DESY accelerator, for measurements.
The electron synchrotron DESY II and the proton synchrotron DESY III were put into operation as pre-accelerators for HERA in 1987 and 1988, respectively.
Today DESY is used as a pre-accelerator for the synchrotron radiation source PETRA III and as a test beam for detector development.
DORIS
DORIS ( Do ppel- Ri ng- S PEICHER ), built from 1969 to 1974 was the second ring accelerator and the first storage ring at DESY. The circumference of DORIS is almost 300 meters . Originally developed as an electron- positron storage ring , DORIS was the first to carry out collision experiments between electrons and their antiparticles at energies of 3.5 GeV per particle beam. In 1978 the energy of the rays was increased to 5 GeV. DORIS was used for particle physics research until 1992.
By observing excited charmonium states , DORIS made an important contribution in 1975 to the detection of heavy quarks . In 1987, the conversion of a B meson into its antiparticle , an anti-B meson, was observed for the first time in the ARGUS detector (originally “A Russian-German-United States-Swedish Collaboration”) of the DORIS storage ring . From this it could be concluded that the second heaviest quark - the bottom quark - can change into another quark under certain conditions. Furthermore, it followed from the observation that the not yet found sixth quark - the top quark - must have a very large mass. The top quark was finally detected for the first time in 1995 at the Fermilab in the USA.
With the establishment of Ha mburger Sy nchrotronstrahlungs lab ors HASYLAB in 1980 the synchrotron originally produced by DORIS as a by-product was used for research. Initially only a third of the DORIS operating time was available for research with synchrotron radiation, from 1993 the storage ring under the name DORIS III served exclusively as a radiation source for HASYLAB and was operated up to 4.5 GeV. In order to obtain more intensive and better controllable synchrotron radiation, DORIS was equipped with wigglers and undulators from 1984 . The accelerated electrons could now be put on a slalom course using a special magnet arrangement . As a result, the intensity of the emitted synchrotron radiation was increased by several orders of magnitude compared to conventional storage ring systems . For two decades, DORIS was one of the five strongest sources in the world and was also the strongest X-ray source in Europe. On October 22, 2012, HASYLAB was separated from DORIS III. The OLYMPUS experiment was still running until January 2, 2013, before DORIS was shut down after almost 40 years of operation.
PETRA
Petra ( P ositron- E lektron- T andem- R ING A nLocated) was built from 1975 to 1978. At the time of commissioning, the accelerator was the largest storage ring of its kind with a length of 2,304 meters and is still the second largest ring accelerator at DESY after HERA. PETRA originally served to research elementary particles. Positrons and electrons could be accelerated to 19 GeV. One of the greatest successes is the detection of gluon , the carrier particle of the strong force , at PETRA in 1979.
Research at PETRA led to more intensive international use of DESY facilities. Scientists from China, England, France, Israel, Japan, the Netherlands, Norway and the USA participated in the first investigations at PETRA.
In 1990 the facility was put into operation under the name PETRA II as a pre-accelerator of protons and electrons / positrons for the new particle accelerator HERA. Electrons or positrons were accelerated up to 12 GeV, protons up to 40 GeV.
In March 1995, PETRA II was equipped with an undulator to generate synchrotron radiation with an intense X-ray light component. After that, PETRA II also served HASYLAB as a source for high-energy synchrotron radiation with two test measuring stations.
PETRA III
On July 2, 2007, the use of PETRA II as a pre-accelerator for HERA ended because HERA was shut down. Then began the conversion from PETRA II to PETRA III, an extremely brilliant X-ray light source. For this purpose, about 300 meters of the 2.3 kilometers of the ring were completely rebuilt and equipped with 14 undulators. On November 16, 2009, PETRA III was put into operation with 14 new measuring stations. The north (Paul-Peter-Ewald-Halle) and east (Ada-Yonath-Halle) halls were also built to increase the number of measuring stations and thus make the radiation from this light source accessible to more users. After one year of renovation work, research on PETRA III was resumed in April 2015.
HERA
HERA ( H adron- E lektron- R ING A nLocation) with a circumference of 6336 meters, the largest circular accelerator has built the DESY. Construction of the facility located in the tunnel began in 1984. In November 1990 the accelerator was put into operation. The first proton-electron collision took place on October 19, 1991. Thus, the first experiments could begin their measuring operation in 1992. HERA was in operation until the end of June 2007.
The HERA accelerator was built in international cooperation (see "HERA model" ). New technologies were developed for the construction of HERA. HERA was the first particle accelerator in which superconducting magnets were installed on a large scale.
The HERA tunnel is located 10 to 25 meters below the earth's surface and has an inner diameter of 5.2 meters. The same technology was used for the construction that is otherwise used for the construction of underground tunnels. Two ring-shaped particle accelerators run in the tunnel. One accelerates electrons to an energy of 27.5 GeV, the other protons to an energy of 920 GeV. Both particle beams fly through their accelerator rings in opposite directions at almost the speed of light about 47,000 times in one second.
The electron and proton beams could be brought to collision at two points on the ring. Electrons or positrons were scattered on the building blocks of the proton, the quarks. The products of these particle reactions, the scattered lepton and the hadrons resulting from the fragmentation of the proton , were detected in large detectors. In addition, there are two further interaction zones in the HERA-Ring, in which the particles could collide with stationary targets . All four zones are housed in large underground halls, each approx. 1.5 km apart (see research at HERA ).
FLASH
The free-electron laser FLASH ( F ree-electron Las it in H amburg) is a superconducting linac with free-electron laser for radiation in the soft X-ray range. FLASH works according to the SASE principle ( self-amplified spontaneous emission ) and is based on a test facility built in 1997 for the TESLA project, which was expanded in 2003 from approx. 100 meters in length to approx. 260 meters. By April 2006, the facility was first called VUV-FEL ( V acuum - U ltra- V iolet - F reie- E lektronen- L aser). FLASH continues to serve as a test facility for possible future superconducting linear accelerators , in particular the European X-ray laser project XFEL and the International Linear Collider ILC .
In addition to FLASH, FLASH II was opened in 2014, which uses the same accelerator but a new undulator section and offers additional measuring stations.
More accelerators
In addition to the large facilities, there are several small particle accelerators at DESY, most of which function as pre-accelerators for PETRA and HERA. These include the linear accelerators LINAC I (from 1964 to 1991 for electrons), LINAC II (since 1969 for positrons) and LINAC III (since 1988 as a pre-accelerator for protons for HERA).
In addition, the Zeuthen Photo Injector Test Stand (PITZ) has existed at the Zeuthen site since 2001. This is a linear accelerator on which, among other things, the electron sources for FLASH and (since 2015) the European XFEL are studied, optimized and prepared for use in user operations.
research
HERA
HERA was used to study the structure of protons from quarks and gluons and the properties of heavy quarks. HERA was the only storage ring facility in the world in which protons could be made to collide with the much lighter electrons or their antiparticles , the positrons (see also colliding beam experiment ).
The experiments H1, ZEUS, HERMES and HERA-B were housed in the four underground HERA halls, each of which was built and operated by its own international working group. Data from the experiments will continue to be evaluated (as of 2015).
H1
H1 was a universal detector for the collision of electrons and protons and was located in the HERA hall “North”. It was in operation from 1992 to 2007, was 12 m × 10 m × 15 m in size and weighed around 2,800 tons .
The tasks of H1 were the deciphering of the inner structures of the proton, the research of the strong interaction as well as the search for new forms of matter and for phenomena unexpected in particle physics .
H1 was able to show that two fundamental natural forces , the electromagnetic force and the weak force, unite at high energies. At low energies, the weak force is considerably weaker than the electromagnetic force, which is why it is not noticeable in everyday life. With the collision energies of the particles in HERA, however, both forces become equally strong. This helped to show that both forces have a common origin, the electroweak force, and was a major step towards unifying all fundamental forces.
The particle collisions measured in H1 provided information about the strength of the strong force . For the first time, it was possible to measure the strength of the strong force over a large energy range in a single experiment and document the change in strength: the closer the quarks are to one another, the lower the strong force between them. The greater the distance between the quarks, the stronger the strong force that holds the quarks together.
ZEUS
Similar to H1, ZEUS was a universal detector for the collision of electrons and protons and was located in the HERA hall “South”. It was in operation from 1992 to 2007, measures 12 m × 11 m × 20 m and weighed around 3,600 tons.
The tasks of ZEUS are similar to those of the H1 detector. ZEUS and H1 complemented and checked each other in their investigations. All research results mentioned by H1 must be credited to ZEUS to the same extent. The measurements of ZEUS and H1 enabled the understanding of the structure of the proton to be expanded and improved. The particle collisions in HERA simulate a state that prevailed in the universe a short time after the Big Bang . Research on the HERA accelerator has therefore expanded our understanding of the first moments after the Big Bang.
HERMES
HERMES was an experiment in the HERA hall "East" and was operated from 1995 to 2007. The longitudinally polarized electron beam from HERA was used to study the spin structure of nucleons . For this purpose, the electrons were scattered at an internal gas target with an energy of 27.5 GeV . This target and the particle detector were specially designed with spin-polarized physics in mind. The detector was 3.50 m by 8 m by 5 m and weighed about 400 tons .
HERMES investigated how the total spin of a proton is created. Only one third of the total spin of a proton can be explained by the spins of the three main components of the proton, the three valence quarks . HERMES was able to show that the spins of the gluons in the proton also make a significant contribution to the overall spin. The spin of the sea quarks in the proton, on the other hand, only contributes a small part to the total spin.
HERA-B
HERA-B was an experiment in the HERA hall “West” and collected data between 1999 and February 2003. The dimensions of the particle detector were 8 m × 20 m × 9 m and its weight was around 1,000 tons. At HERA-B, the proton beam collided with solid aluminum wires in the detector, creating particles that consist of heavy quarks , including B mesons .
B mesons serve u. a. to study symmetry in physics. B mesons can be used to investigate why the universe today consists almost entirely of matter, although in the Big Bang both matter and antimatter were created in equal amounts. Later, the physicists around HERA-B concentrated on special questions about strong forces, e.g. B. how elementary particles arise from heavy quarks in matter and how these particles react with matter.
The HERA-B particle detector has now also been decommissioned and is now partially dismantled and serves as an exhibition item for visitors. The data evaluation for the physics of the heavy quarks is still ongoing. HERA-B also provided knowledge for modern detector construction and the analysis of large amounts of data in particle physics .
HASYLAB
The Ha mburger Sy nchrotronstrahlungs lab or HASYLAB at DESY was opened in 1980 and serves the research with radiation from the accelerator facilities . HASYLAB uses two types of radiation sources, storage rings , which generate synchrotron radiation when in operation , and linear free-electron lasers , which generate laser- like radiation. The research spectrum ranges from experiments in u. a. Physics , chemistry , biology , biochemistry , molecular biology , medicine , geology and materials science through to application-oriented studies and industrial cooperation.
The first experiments with synchrotron radiation began in 1964 at the DESY ring accelerator , after devices for observing the electron beam had already been installed in the accelerator with the aid of synchrotron radiation. The new radiation source provided focused, intense and short bursts of radiation over a wide spectrum , which was used by a growing group of scientists. The synchrotron radiation from the storage rings DORIS (since 1974) and PETRA (since 1995) was also used by the scientists later .
At the beginning of the 1980s, HASYLAB had 15 measuring stations at the DORIS storage ring. The installation of wigglers and undulators from 1984 made it possible to increase the radiation intensity at the measuring stations. From 1993 until the separation in October 2012, the DORIS storage ring was operated exclusively for the generation of synchrotron radiation and further measuring stations were set up.
The synchrotron radiation from PETRA has been used by HASYLAB since 1995 when PETRA was not used as a pre-accelerator for HERA. Since 2009, after a two-year renovation, PETRA III has been used exclusively for generating synchrotron radiation. This means that one of the world's most brilliant X-ray sources is available for research.
The free-electron laser FLASH in Hamburg has also been in operation as a radiation source since 2004. Researchers can use the laser-like X-ray radiation from FLASH at five measuring stations for scientific experiments.
Examples of applications for radiation from HASYLAB are:
- In 1975 the first tests of X-ray lithography took place at DESY , later the procedure for X-ray deep lithography was further developed.
- In 1984 the first Mößbauer spectrum obtained by synchrotron radiation was recorded at HASYLAB .
- In 1985 the detailed structure of the rhinitis virus could be clarified through the further development of X-ray technology .
- In 1986 it was possible for the first time to use synchrotron radiation to excite individual lattice vibrations ( phonons ) in solids. Inelastic X-ray scattering (IXS) made it possible to investigate the properties of materials that were previously only possible in nuclear reactors with neutron scattering (INS).
- At times, the Osram company used the HASYLAB systems to examine the filaments of their lamps using synchrotron radiation . The new knowledge gained about the glow process made it possible to better control the durability of lamps in certain areas of application.
- At HASYLAB, the smallest impurities in silicon for computer chips are analyzed, the mode of action of catalysts is researched, the microscopic properties of materials are examined and protein molecules are screened with X-ray light from synchrotron radiation.
AMANDA and IceCube
DESY, represented in particular by the Zeuthen site , is involved in two research projects in astroparticle physics , the neutrino telescope Antarctic Muon And Neutrino Detector Array (AMANDA) and the IceCube based on it .
DESY scientists from Zeuthen operate the AMANDA neutrino telescope in international cooperation . Located at the South Pole, AMANDA registers neutrinos that leave their tracks in the ice. Since the neutrinos rarely react with other particles, they can fly through the earth. Neutrinos therefore provide information from areas of the universe that would otherwise be inaccessible to astronomers, e.g. B. from inside the sun or from star explosions .
Scientists from Zeuthen were involved in the development of the AMANDA neutrino telescope. In the meantime, the AMANDA project has been expanded into the IceCube. In this project, DESY is involved in the production of the detector modules and the data evaluation.
theory
The advancement of physics requires a collaboration between theoretical physics and experimental physics . So that this collaboration at DESY is possible, there are scientists at DESY who deal with the theoretical physics behind the experiments.
Particular focus is on particle physics and cosmology . In Zeuthen, DESY operates massively parallel high-performance computers in the “Center for Parallel Computing” . a. can be used for calculations in theoretical particle physics.
Further projects with DESY participation
ILC
The next big project in high energy physics is the International Linear Collider (ILC). ILC is a global project with DESY participation for a 30 to 40 kilometer long linear accelerator in which electrons collide with their antiparticles, the positrons , at energies of up to 1 TeV . The aim of the project is to answer central questions in particle and astrophysics about the nature of matter , energy, space and time, etc. a. for dark matter , dark energy and the existence of extra dimensions to investigate. All interested researchers agreed early on that there should only be one facility of this size in the world.
In August 2004, the "International Technology Recommendation Panel ITRP" recommended building the linear accelerator on the basis of superconducting accelerator technology, which DESY and its international partners jointly developed as TESLA technology and successfully tested in a pilot plant in Hamburg.
XFEL
In 2009, the construction of the X-ray laser XFEL ( X-Ray Free-Electron Laser ) began in European and international cooperation, which extends in a three-kilometer tunnel from the DESY site in Hamburg to Schenefeld . Particles are accelerated in the tunnel and in the end generate X-ray flashes of high intensity and of short duration (approx. 10–100 fs ). This makes the XFEL one of the strongest sources of X-rays on earth, many orders of magnitude stronger than X-rays from today's storage rings , and opens up new possibilities and areas of application for research , e.g. B. chemical reactions of individual atoms can be mapped three-dimensionally. The XFEL was commissioned in 2017.
CFEL
On January 1st, 2008 the Center for Free-Electron Laser Science CFEL started its work. CFEL is a cooperation between DESY and the University of Hamburg with the Max Planck Society MPG.
TESLA technology
TESLA ( TeV-Energy Superconducting Linear Accelerator ) is a project proposal from the year 2000 on what a next-generation particle accelerator could look like. This linear accelerator was to be built in a 33-kilometer-long tunnel from Hamburg to the north-northwest, relatively close to the surface of the earth. The superconducting TESLA technology and other findings from this project flow into both the European X-ray laser project XFEL and the International Linear Collider (ILC).
Chair of the DESY Board of Directors (DESY Directors)
- 1959 to 1970: Willibald Jentschke , founding director
- 1971 to 1972: Wolfgang Paul
- 1973 to 1980: Herwig Schopper
- 1981 to 1993: Volker Soergel , German physicist, 1974 to 1979 Chairman of the Council of the German Electron Synchrotron DESY in the Helmholtz Association, 1981 to 1993 also coordinator for the construction of the HERA electron-proton storage ring
- 1993 to 1999: Bjørn Wiik , Norwegian physicist
- 1999 to early 2009: Albrecht Wagner
- since March 2, 2009: Helmut Dosch , formerly at the Max Planck Institute for Metals Research , Stuttgart
Historical-sociological research on DESY
The shift in focus at DESY to photon science has been investigated by the Wuppertal organizational sociologist Thomas Heinze and his colleagues Olof Hallonsten (University of Lund) and Steffi Heinecke (Max Planck Society). In a series of three essays, the team of authors historically reconstructed the changes at DESY in the years 1962–1977, 1977–1993 and 1993–2009. Heinze et al. use theoretical categories of historical institutionalism in their analysis, in particular the change processes of layering (overlay), conversion (conversion) and displacement (displacement). Heinze and Hallonsten have also shown in two further articles that the theoretical framework of historical institutionalism is also suitable for comparing DESY with other research organizations, in particular with the US SLAC National Accelerator Center in Menlo Park, California. The transformation of DESY is part of a change process in which a new organizational field " photon science " has emerged.
literature
- Erich Lohrmann , Paul Söding : About fast particles and bright light: 50 years of the German Electron Synchrotron DESY , Wiley / VCH 2009
- Olof Hallonsten, Thomas Heinze: From particle physics to photon science: Multi-dimensional and multi-level renewal at DESY and SLAC. Science and Public Policy, No. 40. Oxford University Press, Oxford 2013, pp. 591-603.
Web links
- DESY website
- HASYLAB website
- Erich Lohrmann and Paul Söding : 50 years of DESY (PDF, 55 MB)
- www.weltderphysik.de:
- DESY underground - visit report, with photos and tunnel panorama
- Helmholtz Podcast (mp3) June 07 - DESY from min 02:22 ( Memento from September 28, 2007 in the Internet Archive )
Individual evidence
- ↑ DESY at a glance. In: DESY. Retrieved May 20, 2015 .
- ↑ New facility in Desy - With “Petra III”, researchers from today onwards look into the heart of matter . Hamburger Abendblatt, November 16, 2009
- ↑ desy.de: PETRA III Extension
- ↑ Ilka Flegel, Paul Söding, Robert Klanner (eds.), Das Supermikroskosp HERA - A View into the Inner Heart of Matter , October 2002, accessed on September 6, 2014.
- ↑ desy.de: Extension of the FLASH Facility with FLASH II. Accessed on July 15, 2015 (English).
- ^ Center for Free-Electron Laser Science
- ↑ The CFEL foundation stone has been laid DESY News, 2009
- ↑ DESY under new management - DESY News, March 2, 2010
- ↑ Thomas Heinze, Olof Hallonsten, Steffi Heinecke: From Periphery to Center: Synchrotron Radiation at DESY, Part I: 1962-1977 . Historical Studies in the Natural Sciences, No. 45 . University of California Press, Oakland 2015, pp. 447-492 ( ucpress.edu ).
- ↑ Thomas Heinze, Olof Hallonsten, Steffi Heinecke: From Periphery to Center: Synchrotron Radiation at DESY, Part II: 1977-1993 . Historical Studies in the Natural Sciences, No. 45 . University of California Press, Oakland 2015, pp. 513-548 ( ucpress.edu ).
- ↑ Thomas Heinze, Olof Hallonsten, Steffi Heinecke: Turning the Ship: The Transformation of DESY, 1993–2009 . Physics in Perspective, No. 19 . Springer, Berlin, Heidelberg, New York 2017, pp. 424-451 ( springer.com ).
- ↑ Olof Hallonsten, Thomas Heinze: From particle physics to photon science: Multi-dimensional and multi-level renewal at DESY and SLAC . Science and Public Policy, No. 40 . Oxford University Press, Oxford 2013, pp. 591-603 ( oup.com ).
- ↑ Olof Hallonsten, Thomas Heinze: "Preservation of the Laboratory is not a Mission." Gradual Organizational Renewal in National Laboratories in Germany and the USA . In: Thomas Heinze, Richard Münch (Ed.): Innovation in Science and Organizational Renewal. Historical and Sociological Perspectives. Palgrave Macmillan., New York, pp. 117-146 .
- ↑ Olof Hallonsten, Thomas Heinze: Formation and expansion of a new organizational field in experimental science . Science and Public Policy, No. 42 . Oxford University Press, Oxford 2015, pp. 8414-854 ( oup.com ).
Coordinates: 53 ° 34 ′ 33 ″ N , 9 ° 52 ′ 46 ″ E