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An energy recovery linac (ERL) is a type of linear particle accelerator that provides a beam of electrons used to produce x-rays by synchrotron radiation. [1] First proposed in 1965 [2] the idea gained interest since the early 2000s. [3]
The usefulness of an x-ray beam for scientific experiments depends upon the beam's spectral radiance, which tells how much power of a given wavelength is concentrated on a spot. Most scientific literature on x-ray sources uses a closely related term called brilliance , which counts the rate of photons produced, rather than their power. The energy of a photon is inversely proportional to the photon's wavelength.
Very high power is usually achieved by delivering the energy in short pulses, allowing the apparatus to work within reasonable power demands and cooling limits. Depending upon the pulse length and repetition rate, the average spectral radiance will be much lower than the peak spectral radiance. The peak spectral radiance and the average spectral radiance are both important properties of an x-ray beam. For some experiments, the peak value is most important, but for other experiments, the average value is most important.
As a synchrotron light source, the performance of an energy recovery linac falls between a storage ring and a free-electron laser (FEL). Energy recovery linacs have high repetition rates and therefore high average spectral radiance, but lower peak spectral radiance than a FEL. [4]
While using a recirculating charged particle beam with a magnet lattice resembling that of a storage ring, each particle travels through the recirculating arc before being decelerated in a linac structure. The same linac structure also accelerates new low-energy particles that are continuously injected into the linac. Thus, instead of recycling the particle beam continuously, while its emittance increases by synchrotron radiation emission, only its kinetic energy is recycled, enabling a low beam emittance while maintaining high repetition rates comparable to synchrotrons.
BNL-ERL is aimed at 500mA at 20MeV. It is now under commissioning at the Collider Accelerator Department at Brookhaven National Laboratory. One of the main feature of this ERL is a superconducting laser photocathode RF gun powered by a 1MW CW klystron and equipped with a load-lock system for the insertion of high quantum efficiency photocathodes. This ERF gun will provide high brightness electron beams at an unprecedented average power. The objective of this ERL is to serve as a platform for R&D into high current ERL. In particular issues of halo generation and control, Higher-order mode issues, coherent emissions for the beam and high brightness, high power beam generation and preservation. Following its completion we plan to use it for various applications, such as the generation of THz radiation and high power x rays through compton scattering of laser light off its electron beam. [5]
Cornell University, in partnership with Brookhaven National Laboratory, are in the process of constructing CBETA, [6] [7] an ERL built using FFAG optics and superconducting RF cavities, targeting up to 100 mA of CW electron beam at up to 150 MeV, as part of a research program for a future electron-ion collider.
A recent study suggests to improve CERN's Large Hadron Collider (LHC), the largest accelerator existing at present (2013), by adding to the large storage ring of the LHC a tangential construction of two electron Energy recovery linacs, each of 1008 m length, producing thus the possibility to obtain not only Hadron-Hadron smashes, but also, e.g., Hadron-Electron ones, and thus to improve the LHC into some kind of "LHeC".
For this suggestion, originating from a special committee of CERN physicists, M. Klein (Liverpool university), on the suggestion of the UK's Institute of Physics, received the 2013 mutual Max Born Prize of the British and the German Physical Societies. [8] [9]
DESY, short for Deutsches Elektronen-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 of German Research Centres.
A linear particle accelerator is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline. The principles for such machines were proposed by Gustav Ising in 1924, while the first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University. Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy, serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles for particle physics.
The Large Electron–Positron Collider (LEP) was one of the largest particle accelerators ever constructed. It was built at CERN, a multi-national centre for research in nuclear and particle physics near Geneva, Switzerland.
A collider is a type of particle accelerator that brings two opposing particle beams together such that the particles collide. Colliders may either be ring accelerators or linear accelerators.
A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The magnetic field which bends the particle beam into its closed path increases with time during the accelerating process, being synchronized to the increasing kinetic energy of the particles. The synchrotron is one of the first accelerator concepts to enable the construction of large-scale facilities, since bending, beam focusing and acceleration can be separated into different components. The most powerful modern particle accelerators use versions of the synchrotron design. The largest synchrotron-type accelerator, also the largest particle accelerator in the world, is the 27-kilometre-circumference (17 mi) Large Hadron Collider (LHC) near Geneva, Switzerland, built in 2008 by the European Organization for Nuclear Research (CERN). It can accelerate beams of protons to an energy of 6.5 tera electronvolts (TeV or 1012 eV).
The Compact Linear Collider (CLIC) is a concept for a future linear particle accelerator that aims to explore the next energy frontier. CLIC would collide electrons with positrons and is currently the only mature option for a multi-TeV linear collider. The accelerator would be between 11 and 50 km long, more than ten times longer than the existing Stanford Linear Accelerator (SLAC) in California, USA. CLIC is proposed to be built at CERN, across the border between France and Switzerland near Geneva, with first beams starting by the time the Large Hadron Collider (LHC) has finished operations around 2035.
The International Linear Collider (ILC) is a proposed linear particle accelerator. It is planned to have a collision energy of 500 GeV initially, with the possibility for a later upgrade to 1000 GeV (1 TeV). Although early proposed locations for the ILC were Japan, Europe (CERN) and the USA (Fermilab), the Kitakami highland in the Iwate prefecture of northern Japan has been the focus of ILC design efforts since 2013. The Japanese government is willing to contribute half of the costs, according to the coordinator of study for detectors at the ILC.
The High Energy Accelerator Research Organization, known as KEK, is a Japanese organization whose purpose is to operate the largest particle physics laboratory in Japan, situated in Tsukuba, Ibaraki prefecture. It was established in 1997. The term "KEK" is also used to refer to the laboratory itself, which employs approximately 695 employees. KEK's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics, material science, structural biology, radiation science, computing science, nuclear transmutation and so on. Numerous experiments have been constructed at KEK by the internal and international collaborations that have made use of them. Makoto Kobayashi, emeritus professor at KEK, is known globally for his work on CP-violation, and was awarded the 2008 Nobel Prize in Physics.
High-energy nuclear physics studies the behavior of nuclear matter in energy regimes typical of high-energy physics. The primary focus of this field is the study of heavy-ion collisions, as compared to lighter atoms in other particle accelerators. At sufficient collision energies, these types of collisions are theorized to produce the quark–gluon plasma. In peripheral nuclear collisions at high energies one expects to obtain information on the electromagnetic production of leptons and mesons that are not accessible in electron–positron colliders due to their much smaller luminosities.
The Budker Institute of Nuclear Physics (BINP) is one of the major centres of advanced study of nuclear physics in Russia. It is located in the Siberian town Akademgorodok, on Academician Lavrentiev Avenue. The institute was founded by Gersh Budker in 1959. Following his death in 1977, the institute was renamed in honour of Budker.
The Super Proton Synchrotron (SPS) is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, 6.9 kilometres (4.3 mi) in circumference, straddling the border of France and Switzerland near Geneva, Switzerland.
The Cornell Laboratory for Accelerator-based ScienceS and Education (CLASSE) is a particle accelerator facility located in Wilson Laboratory on the Cornell University campus in Ithaca, NY. CLASSE was formed by merging the Cornell High-Energy Synchrotron Source (CHESS) and the Laboratory for Elementary-Particle Physics (LEPP) in July 2006. Nigel Lockyer is the Director of CLASSE in spring of 2023.
The Proton Synchrotron is a particle accelerator at CERN. It is CERN's first synchrotron, beginning its operation in 1959. For a brief period the PS was the world's highest energy particle accelerator. It has since served as a pre-accelerator for the Intersecting Storage Rings (ISR) and the Super Proton Synchrotron (SPS), and is currently part of the Large Hadron Collider (LHC) accelerator complex. In addition to protons, PS has accelerated alpha particles, oxygen and sulfur nuclei, electrons, positrons, and antiprotons.
The Proton Synchrotron Booster (PSB) is the first and smallest circular proton accelerator in the accelerator chain at the CERN injection complex, which also provides beams to the Large Hadron Collider. It contains four superimposed rings with a radius of 25 meters, which receive protons with an energy of 160 MeV from the linear accelerator Linac4 and accelerate them up to 2.0 GeV, ready to be injected into the Proton Synchrotron (PS). Before the PSB was built in 1972, Linac 1 injected directly into the Proton Synchrotron, but the increased injection energy provided by the booster allowed for more protons to be injected into the PS and a higher luminosity at the end of the accelerator chain.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.
The Low Energy Ion Ring (LEIR) is a particle accelerator at CERN used to accelerate ions from the LINAC 3 to the Proton Synchrotron (PS) to provide ions for collisions within the Large Hadron Collider (LHC).
The CERN Hadron Linacs are linear accelerators that accelerate beams of hadrons from a standstill to be used by the larger circular accelerators at the facility.
The Large Hadron Electron Collider (LHeC) is an accelerator study for a possible upgrade of the existing LHC storage ring - the currently highest energy proton accelerator operating at CERN in Geneva. By adding to the proton accelerator ring a new electron accelerator, the LHeC would enable the investigation of electron-proton and electron-ion collisions at unprecedented high energies and rate, much higher than had been possible at the electron-proton collider HERA at DESY at Hamburg, which terminated its operation in 2007. The LHeC has therefore a unique program of research, as on the substructure of the proton and nuclei or the physics of the newly discovered Higgs boson. It is an electron–ion collider, similar to the plans in the US and elsewhere, although the present design would not include polarized protons.
The Future Circular Collider (FCC) is a proposed particle accelerator with an energy significantly above that of previous circular colliders, such as the Super Proton Synchrotron, the Tevatron, and the Large Hadron Collider (LHC). The FCC project is considering three scenarios for collision types: FCC-hh, for hadron-hadron collisions, including proton-proton and heavy ion collisions, FCC-ee, for electron-positron collisions, and FCC-eh, for electron-hadron collisions.
The LEP Pre-Injector (LPI) was the initial source that provided electrons and positrons to CERN's accelerator complex for the Large Electron–Positron Collider (LEP) from 1989 until 2000.