DESY, short for Deutsches Elektronen-Synchrotron (English: German Electron Synchrotron), is a national research centre for fundamental science located in Hamburg and Zeuthen near Berlin in Germany. It operates particle accelerators used to investigate the structure, dynamics and function of matter, and conducts a broad spectrum of interdisciplinary scientific research in four main areas: particle and high energy physics; photon science; astroparticle physics; and the development, construction and operation of particle accelerators. Its name refers to its first project, an electron synchrotron. DESY is publicly financed by the Federal Republic of Germany and the Federal States of Hamburg and Brandenburg and is a member of the Helmholtz Association.
Functions and mission DESY's function is to conduct fundamental research for solely civil and peaceful purposes. It specialises in particle accelerator development, construction and operation, particle physics, astroparticle physics and photon science research to explore the fundamental relationships between the structure, dynamics and function of matter. In cooperation with its partner organisations, its photon science research spans surface physics, material science, chemistry, molecular biology, geophysics and medicine through the use of synchrotron radiation and free-electron lasers.DESY: Statutes of the Foundation Deutsches Elektronen-Synchrotron DESY. (PDF; 40 KB) In: www.desy.de. 8 December 2021. Retrieved 22 December 2022 (in German).DESY: Mission and guiding principles of the research centre DESY. (PDF; 3 MB) In: www.desy.de. May 2013. Retrieved 22 December 2022.
In addition to operating its own large accelerator facilities, DESY participates in many major international research projects, for example the European X-Ray Free-Electron Laser in Germany, the Large Hadron Collider in Switzerland, the Belle II experiment in Japan, the IceCube Neutrino Observatory at the South Pole and the worldwide Cherenkov Telescope Array Observatory.German Federal Ministry of Education and Research (BMBF): Deutsches Elektronen-Synchrotron – DESY . In: www.bmbf.de. Retrieved 22 December 2022 (in German).
Sites
DESY operates in two locations. The primary location is in the Bahrenfeld quarter of Hamburg. In 1992, DESY expanded to a second site in Zeuthen near Berlin.
Hamburg The DESY Hamburg site is located in the quarter Bahrenfeld, in the west of the city in the district of Altona. Its main accelerators are located here.
Zeuthen Following German reunification, DESY expanded to a second site in Zeuthen near Berlin. In 1939, the German Postal Ministry founded a nuclear physics laboratory there. After World War II, the laboratory was first named "Institute X", to become the Institute for High Energy Physics (), the high-energy physics laboratory of the German Democratic Republic belonging to the Academy of Sciences of the GDR. The institute was merged with DESY on 1 January 1992. It focuses on parallel computing for theoretical particle physics, the development and construction of electron sources for X-ray lasers as well as astroparticle physics with a focus on gamma-ray and neutrino astronomy.Matthew Chalmers: . In: CERN Courier, 8 May 2019. Retrieved 22 December 2022.
Employees and training DESY employs about 3,000 staff members from more than 60 nations. Most staff work at the Hamburg site, with about 270 at the Zeuthen site. These numbers include more than 130 trainees in various industrial-technical professions and about 500 PhD students and postdocs supervised by DESY. In addition, there are numerous master students from various universities.About DESY. In: www.desy.de. Retrieved 27 March 2024.
Budget and financing The research centre is a foundation under civil law financed by public funds. In 2024, DESY had an annual budget of about 359 million euros (according to the German federal budget plan as part of institutional funding).Federal Ministry of Education and Research (BMBF): Bundeshaushaltsplan 2024 – Einzelplan 30, p. 110. In: www.bundeshaushalt.de. Retrieved 30 October 2025 (in German). In addition, it had a project funding income of about 32 million euros. 90% of the annual budget is provided by the German Federal Ministry of Research, Technology and Space and 10% respectively by the Free and Hanseatic City of HamburgFree and Hanseatic City of Hamburg: Gesamthaushalt 2023-2024, p. 76-77. In: www.hamburg.de. Retrieved 30 October 2025 (in German). and the German federal state of Brandenburg.Land Brandenburg: Haushaltsplan 2023/2024 – Band VI, Einzelplan 06, p. 65-66. In: mdfe.brandenburg.de. Retrieved 30 October 2025 (in German).
Particle accelerators and other facilities
DESY's accelerators were not all built at once, but were rather added one by one to meet the growing demand of the scientists for higher and higher energies to gain more insight into particle structures. In the course of the construction of new accelerators, the older ones were converted to pre-accelerators or to sources for synchrotron radiation for laboratories with new research tasks.
DESY
The DESY synchrotron (short for "Deutsches Elektronen-Synchrotron") has been in operation since 1964. Its circumference is 300 m. It was used until 1978 for particle physics experiments and first measurements with synchrotron radiation. Since then, rebuilt and upgraded several times, it has served as a pre-accelerator and as a test beam facility delivering high-energy particle beams for testing detector systems.Test beams at DESY. In: www.desy.de. Retrieved 23 December 2022.
DORIS
The DORIS storage ring (short for Double Ring Storage Facility) operated from 1974 to 2013. It had a circumference of 289 m. Until 1992, it collided electrons with positrons for particle physics experiments (including the ARGUS experiment). From 1980 on, the synchrotron radiation generated by DORIS was used for photon science experiments; from 1993 to 2012, the storage ring served exclusively as a synchrotron radiation source. The particle physics experiment OLYMPUS then ran in 2012 before DORIS was shut down at the beginning of 2013.
PETRA
The PETRA storage ring (short for Positron–Electron Tandem Ring Accelerator) has been in operation since 1978. It has a circumference of 2,304 m. Until 1986, electrons and positrons collided in PETRA for research in particle physics (experiments JADE, MARK-J, TASSO and PLUTO). From 1990 on, PETRA served as a pre-accelerator for the HERA storage ring, and from 1995 on also as a synchrotron radiation source with two test experimental stations. Since 2009, the facility has been delivering hard X-ray beams of very high brilliance to over 40 experimental stations under the name PETRA III.
HERA
The HERA storage ring (short for Hadron–Electron Ring Accelerator) operated from 1992 to 2007. It has a circumference of 6,336 m. It was DESY's largest ring accelerator and Germany's largest research instrument to date. Until 2007, HERA was the only storage ring facility in the world to enable collisions of electrons or positrons with protons for particle physics (experiments H1, ZEUS, HERMES and HERA-B) for studies of the inner structure of the proton.
FLASH
The free-electron laser (FEL) FLASH (short for Free-Electron Laser in Hamburg) has been in operation since 2000. It has a length of 315 m. It is based on a test facility for superconducting accelerator technology built in 1997 for the TESLA project and has served as a user facility for experiments with the generated FEL radiation since 2005. FLASH provides ultrashort light pulses in the extreme ultraviolet and soft X-ray range for seven experimental stations and is also used as a test facility for the development of accelerator and FEL technologies.
European XFEL accelerator
DESY operates the 1.7 km superconducting linear accelerator of the European XFEL X-ray free-electron laser, an international research facility that delivers ultrashort light pulses in the high-energy X-ray range.
PITZ
Since 2001, the DESY site in Zeuthen has been home to the photoinjector test facility PITZ, a linear accelerator used to study, optimise and prepare the electron sources for FLASH and (since 2015) for the European XFEL.
Other facilities The building of the former DORIS storage ring now houses the SINBAD ("Short Innovative Bunches and Accelerators at DESY") accelerator complex with various infrastructures for accelerator R&D: the linear accelerator ARES for accelerator research with ultrashort electron pulses for medical purposes, the AXSIS facility for terahertz-driven acceleration to generate ultrashort X-ray pulses for materials science or medical imaging, and the high-power laser KALDERA for research into laser-driven plasma acceleration.
The LUX facility is also used for research into laser-driven plasma acceleration, the FLASHForward experiment at FLASH for electron-beam-driven plasma acceleration. The relativistic electron beam source REGAE generates ultrashort electron pulses for time-resolved diffraction experiments.
The tunnel of the former HERA storage ring now houses the ALPS II experiment, which uses converted superconducting dipole magnets of the HERA proton ring to study extremely light particles.
Computing DESY provides extensive storage and computing capacity for research in all its divisions within the Interdisciplinary Data and Analysis Facility (IDAF).Christoph Beyer et al.: „Beyond HEP: Photon and accelerator science computing infrastructure at DESY“. In: EPJ Web Conf., 245 07036 (2020). Retrieved 22 September 2025. DOI 10.3204/PUBDB-2020-04519.IDAF: Interdisciplinary Data and Analysis Facility. In: www.desy.de. Retrieved 22 September 2025. The Maxwell HPC Cluster, a high-performance computing platform, serves photon science analysis and accelerator science and operations.Maxwell HPC Cluster. In: www.desy.de. Retrieved 22 September 2025. As part of the Worldwide LHC Computing Grid (WLCG), DESY operates a Tier-2 computer centre that offers computing and storage systems for the ATLAS, CMS and LHCb experiments at the Large Hadron Collider (LHC). In addition, the DESY grid infrastructure is used by other experiments such as Belle II or IceCube.DESY Grid. In: www.desy.de. Retrieved 22 September 2025. It is complemented by the National Analysis Facility (NAF) for particle physics data analysis.NAF: National Analysis Facility. In: www.desy.de. Retrieved 22 September 2025.Computing infrastructure. In: www.desy.de. Retrieved 23 December 2022. IDAF storage is provided using DCache and General Parallel File System (GPFS).
Research areas Research at DESY is organised into four divisions: Accelerators, Photon Science, Particle Physics and Astroparticle Physics.
The Accelerator division develops fundamental technologies for the accelerator facilities that DESY and its partners use in their scientific mission. In addition to the operation and further development of existing facilities (PETRA IV and FLASH2020+ projects, expansion of the European XFEL), essential activities include research into new accelerator concepts, in particular plasma wakefield acceleration, and the improvement of superconducting radio frequency accelerator technology.DESY: Accelerators 2021. Highlights and Annual Report. (PDF; 13 MB) In: www.desy.de. Retrieved on 23 December 2022.Sven Kiele et al: National Strategy for the Further Development of Accelerator-Based User Facilities for Research with Photons and with High Electromagnetic Fields ("Helmholtz Photon Science Roadmap"). (PDF; 6 MB). In: www.helmholtz.de. 15 June 2021. Retrieved 23 December 2022 (in German).