Editing DESY (section)

== History ==
[[Image:Desy.jpg|thumb|German 1984 postal stamp – 25th anniversary of the foundation of DESY]]

DESY was founded on 18&nbsp;December 1959 in Hamburg.<ref name="Lohrmann_Söding_CC"> Erich Lohrmann, Paul Söding: [https://cerncourier.com/a/desy-marks-50-years-of-accelerator-research/ "DESY marks 50 years of accelerator research"]. In: CERN Courier, 7 December 2009. Retrieved 23 December 2022.</ref> According to its statutes, DESY's mission is "the promotion of basic scientific research [...] in particular through the development, construction and operation of accelerators and their scientific use, in photon science and in the fields of particle and astroparticle physics, as well as through research and development work related thereto".<ref>DESY: Statutes of the Foundation [https://www.desy.de/sites2009/site_www-desy/content/e410/e207099/e207101/211208_DESY-Satzung_ger.pdf Deutsches Elektronen-Synchrotron DESY]. (PDF; 40 KB) In: www.desy.de. 8 December 2021. Retrieved 23 December 2022 (in German).</ref>

[[Image:DESY2.jpg|thumb|The [[ARGUS (experiment)|ARGUS]] detector at the former electron–positron storage ring DORIS at DESY]]

[[File: 1980-09-22 TASSO-Event Gluon Entdeckung sw.jpg |thumb|In 1979, the particle physics experiments at the electron–positron storage ring PETRA at DESY discovered the gluon, the messenger particle of the strong force.]]

From 1959 to 2007, the DESY accelerators were primarily used for [[particle physics]], initially with the eponymous [[DESY (particle accelerator)|DESY electron synchrotron]] (1964–present), followed by [[DORIS (particle accelerator)|DORIS]] (Double Ring Storage Facility, 1974–1992), [[PETRA]] (Positron–Electron Tandem Ring Facility, 1978–present) and [[HERA (particle accelerator)|HERA]] (Hadron–Electron Ring Accelerator, 1992–2007). In 1987, the [[ARGUS (experiment)|ARGUS]] experiment at DORIS was the first to observe a large mixing of [[B mesons]] and thus a process in which matter and [[antimatter]] behave differently.<ref name=" Lohrmann_Söding_CC " /><ref>Till Mundzeck: [https://cerncourier.com/a/the-three-lives-of-doris-from-charm-quarks-to-cell-biology/ "The three lives of DORIS: from charm quarks to cell biology"]. In: Cern Courier, 27 November 2012. Retrieved 23 December 2022.</ref> The most important discovery of the experiments [[TASSO]], [[JADE (particle detector)|JADE]], MARK-J and [[PLUTO detector|PLUTO]] at PETRA was the detection of the [[gluon]], the messenger particle of the [[strong force]], in 1979.<ref name=" Lohrmann_Söding_CC " /> From 1990, PETRA served as a pre-accelerator for the even larger [[storage ring]] HERA with its four experiments [[H1 (particle detector)|H1]], [[ZEUS (particle detector)|ZEUS]], [[HERMES experiment|HERMES]] and [[HERA-B]]. HERA was the only storage ring facility in the world in which [[proton]]s collided with electrons or [[positron]]s. In these collisions, the point-like electron acted like a probe, scanning the inner structure of the proton and making it visible with high resolution. HERA's precise insights into the interior of the proton formed the basis for numerous other particle physics experiments, especially at the [[Large Hadron Collider]] (LHC) at the research centre [[CERN]] and for numerous developments in theoretical particle physics.<ref name=" Lohrmann_Söding_CC " /><ref>Rolf-Dieter Heuer, Albrecht Wagner: [https://cerncourier.com/a/hera-leaves-a-rich-legacy-of-knowledge/ "HERA leaves a rich legacy of knowledge"]. In: Cern Courier, 21 January 2008. Retrieved 23 December 2022.</ref>

[[File:PETRA III Max von Laue Hall 2014.png|thumb|"Max von Laue" experimental hall at the synchrotron radiation source PETRA III on the DESY campus in Hamburg]]

In parallel, as early as the 1960s, research groups from DESY, various universities and the [[Max Planck Society]] developed the technology for using the [[synchrotron radiation]] produced by the accelerators.<ref>Thomas Heinze, Olof Hallonsten, Steffi Heinecke: "From periphery to center: Synchrotron radiation at DESY, Part I: 1962–1977". Historical Studies in the Natural Sciences 45, 447–492 (2015) [https://doi.org/10.1525/hsns.2015.45.3.447 DOI 10.1525/hsns.2015.45.3.447]</ref> To meet the rapidly growing national and European demand, DESY founded its own large laboratory: the Hamburg Synchrotron Radiation Laboratory HASYLAB, which opened in 1980.<ref>Thomas Heinze, Olof Hallonsten, Steffi Heinecke: "From periphery to center: Synchrotron radiation at DESY, Part II: 1977–1993". Historical Studies in the Natural Sciences 45, 513–548 (2015) [https://doi.org/10.1525/hsns.2015.45.4.513 DOI 10.1525/hsns.2015.45.4.513]</ref> It provided measuring stations at DORIS, and it was here that the Israeli biochemist [[Ada Yonath]] (Nobel Prize in Chemistry 2009) conducted experiments from 1986 to 2004 that led to her deciphering the [[ribosome]].<ref name=" Lohrmann_Söding_CC " /><ref>Till Mundzeck: [https://cerncourier.com/a/the-three-lives-of-doris-from-charm-quarks-to-cell-biology/ "The three lives of DORIS: from charm quarks to cell biology"]. In: Cern Courier, 27 November 2012. Retrieved 23 December 2022.</ref> From 1995, both synchrotron radiation and particle physics experiments were conducted at PETRA. In 2009, the PETRA facility was upgraded for exclusive use as a [[synchrotron light source|synchrotron radiation source]] for [[X-ray#energy ranges|hard X-rays]] (PETRA III).<ref name=" Lohrmann_Söding_CC " /> Today, PETRA III serves over 40 experimental stations, and there are plans to expand it into the PETRA IV 3D X-ray microscope.<ref>[https://www.wayforlight.eu/facility/20469 PETRA III at DESY]. In: www.wayforlight.eu. Retrieved 23 December 2022.</ref><ref>Christian Schroer et al.: "PETRA IV: the ultralow-emittance source project at DESY". In: J. Synchrotron Radiat. 25 (5), 1277–1290 (2019). Retrieved 23 December 2022. [https://doi.org/10.1107/S1600577518008858 DOI 10.1107/S1600577518008858].</ref> With the shutdown of DORIS in early 2013, the name HASYLAB was abandoned, and the use of DESY's light sources has since been carried out in its Photon Science division.

[[File: 2015-04-10 FLASH2 DN-MKX-4904.jpg |thumb|In the free-electron laser FLASH at DESY, electrons generate laser light in the soft X-ray range as they pass through special magnetic arrangements known as undulators (yellow).]]

In the early 1990s, DESY began to develop a new technology: [[radio frequency]] accelerator technology based on [[superconductivity|superconducting]] [[resonator#cavity resonators|cavities]] made of [[niobium]], which are cooled to approximately 2&nbsp;K (−271&nbsp;°C) with liquid [[helium]]. The first accelerator on this basis was a test facility for superconducting [[linear accelerator]]s at DESY to test the principle of [[self-amplified spontaneous emission]] (SASE) of X-ray laser light.<ref>Jochen Schneider, Ilka Flegel: [https://cerncourier.com/a/flash-the-king-of-vuv-and-soft-x-rays/ "FLASH: the king of VUV and soft X-rays"]. In: CERN Courier, 30 November 2010. Retrieved 23 December 2022.</ref> The SASE theory was developed and refined at DESY and at institutes in Russia, Italy and the USA from 1980 onwards.<ref>A.M. Kondratenko and E.L. Saldin: [https://s3.cern.ch/inspire-prod-files-8/872da099a0e9c171a4dca19256f7ca0e "Generation of Coherent Radiation by a Relativistic Electron Beam in an Ondulator"]. In: Part. Accelerators 10, 207–216 (1980). Retrieved 23 December 2022.</ref> In 2000 to 2001, the test facility at DESY was the first [[free-electron laser]] in the world to produce light flashes in the [[ultraviolet#Subtypes|vacuum ultraviolet]] and [[X-ray#energy ranges|soft X-ray]] range.<ref>Jochen Schneider, Ilka Flegel: [https://cerncourier.com/a/flash-the-king-of-vuv-and-soft-x-rays/ "FLASH: the king of VUV and soft X-rays"]. In: CERN Courier, 30 November 2010. Retrieved 23 December 2022.</ref> Today, the [[FLASH]] facility produces ultrashort light pulses in the soft X-ray range for seven experimental stations.<ref>[https://www.wayforlight.eu/facility/23603 FLASH at DESY]. In: wwwwayforlight.eu. Retrieved 23 December 2022.</ref> Since 2020, it has been expanded to further optimise the properties of the radiation (FLASH2020+ project).<ref> Ralf Röhlsberger et al.: "Light Source Upgrades at DESY: PETRA IV and FLASH2020+". In: Synchrotron Radiat. News 32 (1), 27–31 (2019). Retrieved 23 December 2022. [https://doi.org/10.1080/08940886.2019.1559605 DOI 10.1080/08940886.2019.1559605]</ref>

From 2009 to 2016, an international consortium led by DESY developed the European X-ray free-electron laser [[European XFEL]]. The international research facility, which involves 12 European shareholder countries, is operated by the non-profit company European XFEL [[GmbH]]. The core of the facility is a 1.7&nbsp;km superconducting linear accelerator. With an electron energy of 17.5&nbsp;GeV, it is the most powerful superconducting linear accelerator in the world to date. DESY operates the accelerator on behalf of European XFEL GmbH.<ref>[https://www.xfel.eu/facility/overview/desy/index_eng.html DESY and the European XFEL]. In: www.xfel.eu. Retrieved 23 December 2022.</ref><ref>Eric Beaurepaire, Fabrice Scheurer, Hervé Bulou, Jean-Paul Kappler (eds.): "Magnetism and Synchrotron Radiation", Springer, Berlin Heidelberg 2010, ISBN 9783642044984, p. 416.</ref>

Since 2010, DESY has been developing [[plasma acceleration|plasma-based accelerator technology]] (both laser- and electron-beam-driven) as a possible alternative to conventional accelerator technologies, with the aim of enabling compact accelerators for photon science, particle physics as well as medical and industrial applications.<ref>DESY: [https://www.desy.de/sites2009/site_www-desy/content/e410/e84441/e326618/Accelerators2021_ger.pdf Accelerators 2021. Highlights and Annual Report]. (PDF; 13 MB) In: www.desy.de. 1 May 2022. Retrieved 23 December 2022.</ref>