Particle accelerator - SpeedyLook encyclopedia

The particle accelerator are instruments which use electric fields and/or magnetic to bring particles electrically charged to high Speed S. In other words they communicate energy with the particles.

One distinguishes two main categories from them: linear accelerators and circular accelerators.

In 2004 there was more 15 000 accelerators in the world. A hundred only are very large installations, main roads or supranational (CERN). The electrostatic machines of industrial type compose more than 80% of the world park of the industrial accelerators of electrons. Very many small linear accelerators are used in medicine (antitumor radiotherapy).

History

In 1919, the physicist Ernest Rutherford (1871-1937) transformed nitrogen atoms into isotopes of oxygen atom by bombarding them with particles alpha generated by a natural radioactive isotope. But the study of the atom and especially of its core requires very high energies. The particles coming from the natural radioelements are too very few and not very energy to penetrate the barrier of potential of the core of the heaviest elements. The potential on the nuclear surface grows of a million volts for ordinary hydrogen to 16 million for uranium. The astroparticules (cosmic rays) allowed major discoveries but their energy is very variable and it is necessary to go to seek them in altitude where they are less rare and energy. In the years 1920, it appears obvious that a thorough study of the structure of the matter was going to require energy and more controlled beams particles. The source of the particles charged was varied. The discharges in gases produce ions, whereas for the electrons, it was possible to use the emission by a heated wire or other systems. The energy (E) of a particle in an electric field corresponds to the product of its load (Q) multiplied by the tension (U) of the field: E = q.U. Thus, a first possible solution was primarily to accelerate the particles in a vacuum tube subjected to very an high voltage. The race to the million volts had started. Several systems were proposed.

In England John Cockcroft and Ernest Walton, which, in 1932, achieved the first successful disintegration of the core by electrically accelerated particles, used a multiplier of tension using a complicated assembly of Redresseur S and Condensateur S (Greinacher assembly, 1919). Without any doubt, one of the best ideas was developed by Robert Jemison VAN DE GRAAFF, who chooses to develop a machine starting from the electrostatic antique. Finally, the others (such as Ernest Orlando Lawrence with its Cyclotron) chose a completely different way: renonçant to obtain from a blow the 10 or 20 MeV necessary to penetrate all the cores Ernest Orlando Lawrence thought of reaching these energies by successive alternative electric impulses. Periodic impulses suppose the maintenance of a certain synchronism with the accelerated particle which naturally describes a straight line at very an high speed. By using a powerful electromagnet in the air-gap of which the particles are confined by the magnetic field itself, E.O. Lawrence has solved simultaneously the two problems.

The principal ingredients necessary to accelerate the particles are the electric fields and magnetic and a Vide of good quality.

The classification of the particle accelerators can follow the history of technologies employed: for example, the electrostatic accelerator, machines “tandem”, linear accelerators with ultra high frequencies, the cyclotrons (of which the isochronous cyclotron and the bétatron), the synchrotrons (of which the synchrocyclotron, synchrotrons with protons, electrons), the rings of the collisions (rings electron-positron, rings of collision to protons). Of course, each machine can be associated with the historical discoveries which they allowed.

Classification by energy: Low energies of 10-100 MeV. Average energy of 100-1000 MeV. High energies more than 1 GeV and the TeV (Tera électronvolt=10¹² eV).

Other classifications are possible according to the applications of the accelerator: industry, medicine, basic research, exploration and comprehension of the elementary components of the matter, energy and space and time.

More simply, these very large machines of the S can be classified according to the geometry of the trajectories of acceleration: linear or circular. The fundamental character of many modern accelerators is the presence of a magnetic field rolling up the trajectories in the form of circles or of spirals. One can call them “circulars”. Others accelerate in straight line, they are called “rectilinear or linear”.

The diagram of Livingston

Stanley Livingston, physicist specialist in the particle accelerators, established this diagram in the years 1960. It shows the exponential growth of the energy of the beams accélérés.
This traditional diagram is modified : the horizontal axis was extended to the years 2010. The vertical axis was extended to 100000 TeV. To compare the various accelerators, the energy of the colliders, which is expressed in the center of mass, was recomputed as if the energy of the particles observed were the result of a collision with a proton at rest. The cost by eV of energy of the beam is tiny room of a factor 1000 per period of 7 ans.
Dans the past, one gained a factor 10 the every 7-8 years in the energy of the collisions carried out. If the evolution had been maintained, one would have reached 60 TeV since 2005. LHC (Broad Collider High-energy particle, 7 TeV + 7 TeV, CERN, 2008) thus does not follow extrapolation. One notes a Net decline in the performances which perhaps indicates a first sign of tiredness of the discipline.

Applications

The accelerators have applications as varied as

the Nuclear physics (production of neutrons), for the fundamental Recherche on the elementary particles of high energies.
the medical field, for the treatment of the Cancer S by Radiotherapy.
the military field, in particular for the simulation of the nuclear weapons.

In fundamental physics, they are used to accelerate beams of particles charged (electrons, positrons, protons, antiprotons, ions…) to make them enter in collision and study the elementary particles generated during this collision. The energy of the particles thus accelerated is measured in electronvolt S (eV) but the units are often the million (1Mev=10⁶ eV), the billion electronvolts (1Gev=10⁹ eV). high-energy physics (or subnucléaire or of the elementary particles) precisely definite starting from GeV and beyond that.

Common characteristics

All the particle accelerators consist of several successive subsets, fulfilling various functions, of the source to the target and in a high vacuum:

Production and emission of the particles charged (for example thanks to a Cathode): ions (Proton) or electron S in general, antiparticles like the antiproton and the positron.
injection in the air space cylindrical tube where the particles will be accelerated.
acceleration itself (possibly by several successive sections), using various technical processes: continuous or alternate electric fields high frequency.
the focusing of the beam to prevent its divergence (magnetic lenses).
finally preparation of the beam of particles to its use:

deflecting which moves the beam in the desired direction.
system of collimation (also for the medical applications).
detecting of the particles.
target (thick or thin), metal intended to produce x-rays of high energy (in particular for the medical applications). The target can be another beam.
connection with another accelerator (research in physics of the particles).

Rectilinear or linear accelerators

One finds several techniques of acceleration, for example:

electrostatic accelerators : A static high voltage is applied between 2 electrodes thus producing a static electric field :

the multipliers of tension (combination in cascade of condensers and rectifiers) of type Greinacher or Cockcroft and Walton make it possible to obtain high voltages which have the characteristics of the properly electrostatic machines (Singletron®, Tandetron® of HVEE). The energy acquired by the particles is equal, in electronvolt S, with the potential difference.
the Electron microscope is most known of the electrostatic accelerators. Acceleration under a few hundreds of KeV provides wavelengths adapted to dimensions of the cells, viruses, microcrystals and larger molecules.
the electrostatic generator most typical is the Générateur of VAN DE GRAAFF: the potential difference is of some MeV (20 MeV for the accelerator-tandem of the type Vivitron® or Laddertron® or Pelletron®). To increase energy with constant tension, one can only increase the electric charge. But the sources of multichargés ions are, in general, complexes, and it is not very convenient to place them in an electrode high voltage. The electrostatic accelerator tandem (1958) brings a solution to this problem. The ions produced by the source are accelerated until the medium of the tube (potential +V). They cross a cleaner of electrons ( stripper ), while passing through a small quantity of matter (small gas section or very thin carbon or metal sheeting). The positive ions thus formed are accelerated by the tension V. final energy is worth (n+1) eV then if N is the number of load of the provided ion. The source of ions and the target are both with the mass (or ground). For protons, final energy is the double of that permitted by a traditional machine. The heaviest ions can reach final energies several hundreds of MeV.

linear accelerators with radio frequencies of the type Wideroë (1928) or Alvarez (1947) . Usually called LINAC (elements laid out in straight line): the trajectory of the particles is always rectilinear, but the electric field is high frequency . The alternative sources High frequency used are almost always Klystron S (amplifying tubes ultra high frequencies) whose power of peak can reach 60 MW. The particles are accelerated by successive impulses suitably synchronized without having to isolate from the potential differences equivalent to final energy. The beam while passing in a succession of cavities where reign an alternate electric field will be able to reach an energy of a few hundreds of MeV. One distinguishes two more types according to whether it is a question accelerating from ions (low energies) or electrons (high energy). The linear accelerators are older than the circular accelerators; they appeared as of 1931 with the linear accelerator of Wideroë, taken again by Sloan and Lawrence with the the United States. In France, at the beginning of the Years 1960, one built with Orsay in the Essonne a linear accelerator and its Ring of Collision (ACO) whose energy was about the GeV. The accelerator linear did not make it possible, initially, to produce beams of as great energy as the circular accelerators. On the other hand they have many advantages. Indeed, the geometry is “open”, i.e. that one can send or extract the beam easily and a beam of high flow could be transported with current technologies. They are often used as injectors of beams in the great structures (circular colliders), and now developed like elements of large linear colliders. Currently, the largest linear accelerator in the world is that of Stanford in the United States: to see the Center of the linear accelerator of Stanford. Length 3050 meters, many Klystrons 244. Power of peak per klystron: 30 MW. Maximum energies 24 GeV (33, 4 GeV with cavities High frequency of storage). Peak current: 80 my. The enormous power transported by the beam (1 continuous MW) poses technological problems.

Circular accelerators

In fact the circular accelerators hold the record of energy. It is easy to include/understand why. The energy received per meter of trajectory, i.e. the intensity of the accelerating electric field, is limited by physical and technical factors. In “rolling up” the trajectory, one obtains the equivalent of a rectilinear accelerator having, not kilometers, but thousands of kilometers length.

Among the “circulars” one distinguishes initially those which employ a magnetic field fixes , (and a massive magnet) and where, consequently, the trajectories are spirals: they are the cyclotron (E. Lawrence, 1929) and the synchrocyclotron (conceived in Berkeley in 1946). On the contrary, in the synchrotrons (E. Mc Milan and V. Veksler), the magnetic field varies during acceleration, so that this one takes place on an invariable circle and that the electromagnet (annular) is, with equal energy, considerably reduced. The synchrotrons are thus, for economic reasons, the accelerators making it possible to have orbits of very large ray.

One thus distinguishes two types of circular accelerators:

the Cyclotron S:

Machines with Synchrotron radiation

Storage rings

They are used to put on standby and to reinforce the beams of particles who will be injected into the accelerator collider. The storage rings can act as colliders when the beams stored on separate orbits are put in interaction (by short-circuit of the electrostatic high voltage of separation).

the shock of face (in the center of mass) of two beams of particles releases all the kinetic energy acquired during acceleration. The useful profit of energy is considerable. That does not go without difficulties, because the density of the particles in the beam of an accelerator is much lower than the density of the cores in a fixed target. To obtain a detectable rate of interaction, it is thus necessary to have very intense currents accelerated, which led to the development of the techniques of storage and accumulation of the beams. It is about a synchrotron which one keeps the constant magnetic field. Two electron beams and of positrons can circulate there simultaneously. The storage ring can function out of ring of collision.

the Ring of Collision of Orsay (ACO) functioned of the beginning of the year 1960 until in 1988.Pour causing collisions between puffs of electrons and puffs of positrons, the particles were injected at the rate of ten puffs a second. One needs thousands of puffs to form a stored beam. On the whole, the injection of the two types of particles lasted approximately half an hour.

storage rings to intersection ( Intersecting Storage Boxing rings ; ISR) make it possible to store in two separate rings only one type of particle. The beams of protons cross into 6 or 8 points. The ISR ( CERN, 1971-1984 ) were a technical exploit but the results of their physics were not with the height. They made it possible to observe the production of particles with great transverse impulse.

Colliders

The current machines of point are colliders.

To examine the intimate structure of the components of the atomic nucleus the accelerators must accelerate the particles beyond 1 GeV. The laws of quantum mechanics make it possible to describe the particles at the same time by their physical trajectory and their function of wave. If the wavelength of the particle probe is short, the matter can be examined on an extremely small scale. Quantum mechanics connects this wavelength with the energy of the particles entering in collision: the shorter energy is high, is the wavelength. There is another reason with the use of high energies. The majority of the objects which interest the physicists of the elementary particles today do not exist in a free state in nature; they must be created artificially in laboratory. The famous equation E=mc² control surface the energy of necessary collision E to produce a particle of mass m . Several of the most interesting particles are so heavy that energies of collision of hundreds of GeV are necessary to create them. In fact to include/understand and consolidate the current theories it is necessary to go beyond TeV (by building accelerators allowing physics Terascale ).

There are four category of colliders: electrons against positrons, high-energy particles against high-energy particles (protons against protons, proton against antiprotons, electron against protons), ions against ions.

Circulars

These accelerators colliders are similar to the synchrotrons in the direction where the particles also circulate along a circular trajectory of ray invariant. The difference is that the colliders produce collisions directly between two beams of particles accelerated in opposite direction and either on a fixed target. The invention of the colliders makes it possible to overcome the fall of output (related to the laws of relativistic mechanics) of the accelerators when energy grows. The shock between an accelerated proton, for example, with a proton at rest generates, in the system of the center of mass , an energy much weaker than the energy of the projectile. The proportion of energy really usable decrease with the energy of the projectiles. If one makes enter in collision two particles of opposed directions, each one having energy E , energy in the center of mass will be equal to 2nd . Such a shock makes it possible to use all produced energy, and not a fraction as in the fixed target experiments of the traditional accelerators. With CERN, Geneva, the Super Proton Synchrotron (SPS) reached energies of 450 GeV. It was used as injector with the Broad Electron Positron (LEP) and will be used for the future Broad High-energy particle Collider (LHC, 21e century) which will largely use the Supraconductivité.

Linear

linear colliders electron-electrons .
the linear collider electrons - positons of Stanford:
L' ICL (International Linear Collider) is in process of study with the SLAC (21e century). With the Broad High-energy particle Collider of the CERN, it will make it possible, between 2012 and 2019, to explore the matter beyond our current knowledge (and of the possibilities of the current accelerators). The nature of the collisions with the ILC should make it possible to supplement the questions raised by discoveries of the LHC (dark matter, existence of the supersymmetries). Two 20 kilometers length LINAC will face. The electron beams and of positrons will 99.9999999998% reach each one 99,9999999998% speed of light. Each beam will contain 10 billion electrons or positrons compressed in a section of three nanometers. To go collisions, the accelerating cavities with Supraconductivité will operate at a temperature close to the absolute zero. The beams will enter in collision 2000 times a second.

Elastic collision and inelastic collision

The system of the laboratory is that where the experimental device is with the repos.
the system of the center of mass is that where the two initial particles have equal impulses and opposées.
After an elastic collision , the two incidental particles are preserved, only their impulses are modified. In the center of mass only the directions of the particles have changé.
After an inelastic collision , other particles are created, in the place or in addition to the incidental particles. Part of energy was transformed into mass. The vectorial sum of the impulses is preserved.

Cross section and luminosity

The probability of an interaction at the time of the collision between two particles is called its cross section (dimension of a surface L ²). Its unit is the barn (b). 1 B = 10^-24 cm².Les rare or very rare processes are expressed under multiples of the barn: µb (microbarn), Nb (nanobarn), Pb (picobarn), Bfr (femtobarn).
the quality of a collider to produce collisions is called its luminosity . It is measured in cm^-2.s^-1.La high luminosity of a collider is as important as high energy in the search for rare events. For example the Broad High-energy particle Collider will have a luminosity of 10³⁴cm^-2s^-1 in nominal mode.

Manufacturers

Electrostatic accelerators

The commercial production of the accelerators with D.C. current began at the end of the years 1930 with the series from Cockcroft-Walton machines built by Philips in Eindhoven. In France at the end of the second world war, No5el Felici in Grenoble started to build electrostatic generators with cylinder functioning in hydrogen. The SAMES built and marketed Felici generators of 1MV and 100µA until they are détrônés by the generators with rectified currents. In Switzerland, Haefely developed multiplying generators of tension, pressurized in air to feed from the injectors of cyclotron. J. VAN DE GRAAFF and his/her colleagues created in 1946 HVEC (High Voltage Engineering Corporation). Electrostatic accelerators of electrons and ions, with energies from 0,4 to 5,5 MeV started production. The request was such as a European subsidiary company began a production in the Netherlands under the name of HVEE (High Voltage Europa Engineering). The production of electrostatic accelerators Tandem started in 1958. In the USSR the production of accelerators with belt started in 1955 in Leningrad ( Research institute into electrophysic Efremov ). Simple electrostatic accelerators with 5MV and a vertical Tandem of 6MV were designed in the USSR and were exported in Finland, China and elsewhere. In 1958 Radiation Dynamics Inc. built multiplying generators of tension of the Dynamitron type imagined by Cleland, to feed from the accelerators of electrons and ions. Ray Herb replaced the belt of the VAN DE GRAAFF by a system of load per chain alternating nylon element and steel elements: the Pelletron system. In 1964 it founded NEC (National Electrostatics Corporation) which built vertical and horizontal accelerators for research and the nuclear physics. One owes him Pelletron of 25 MV of Oak Ridge (world records in this class of electrostatic accelerators). In 1978 Purser, at General Ionex Corporation , started to manufacture small tandem accelerators for research by using the system invented by Cleland. Under the name of Tandetron and Singletron , these machines based on generators with D.C. current are now manufactured by HVEE. In 1984 Letournel in Strasbourg created VIVIRAD (at the origin of the manufacture of the VIVITRON).

Other accelerators

The history of the manufacturers of the cyclotrons and the synchrotrons remains to be written. The large equipment was the subject of a co-operation where the names of General Electric are found, Siemens, the general Company of radiology, Alsthom, Mitsubishi, Kraftanlagen, Argos.

In the medical applications (radiotherapy) the small linear accelerators are built by Varian Clinac (Varian - Linear accelerators), Siemens , Elekta , OSI (International Oncology Services), IBA (Ion Beam Application) with Leuwen-the-New, Belgium.

The 20 km of electromagnets of the LHC are wound with 7000 kilometers of superconductive cable. This cable is produced, since the year 2000, in four factories in Europe, one in Japan and one in the United States. On the whole, four companies are implied in this production: Alstom , European Advanced Superconductors , Outokumpu and Furukawa .

Contributions of the Supraconductivity

One of the technological advance most important of the years 1970-1990 was the control of the superconductors intended for the magnets and the accelerating cavities. Certain metals cooled at a temperature close to the absolute zero (- 273 °C) lose any electrical resistance then, which makes it possible to make there circulate without loss of the high currents. To manufacture superconductive electromagnets was a succession of difficulties related to the quenching (the magnetic field can deteriorate supraconductivity and thus superconductive metal). The electromagnets must reach 4 to 5 Teslas (40000 to 50000 Gauss) to be used in the accelerators. The goal was reached with the Tevatron thanks to a ring of superconductive magnets. Supraconductivity can reduce the electricity consumption of the cavities to radio frequencies, especially in the colliders electron-positrons, where energy is dissipated in heat almost as far as it is communicated to the particles.

List accelerators

See also: List of the accelerators in physics of the particles

See ''' the list ''' updated regularly by ELSA, institute of physics, university of Good (Germany).

Geographical sites

the United States: Brookhaven, Cornell, Stanford, Fermilab

Tevatron with the Fermilab with Chicago (E. - U.) 1984: Synchrotron with protons of 1 TeV with superconductive magnets - 1986: Collider proton-antiprotons. With license the description of the quark signal in 1995 (174 GeV).
RIA with the Michigan State University] ([[the United States of America|E. - U.]]) * [http://www.slac.stanford.edu/ SLAC] in Stanford. The particle accelerator 3,2 km length located on the site is the longest linear accelerator in the world. ([[the United States of America|E. - U.]]). * [http://www-project.slac.stanford.edu/ilc/ ILC in Stanford] * [[Relativistic Heavy Ion Collider|RHIC]] with Upton, New York ([[the United States of America|E. - U.]]) [http://www.bnl.gov/RHIC/ Official site]. ''' France ''' * [http://www.lal.in2p3.fr/ LAL] [[Laboratory of the Linear Accelerator]], Orsay, France * [[VIVITRON]] in Strasbourg ([[France]]) Stop of activity in 2003. * [[European Synchrotron Facility Radiation|ESRF]] with [[Grenoble]] ([[France]]): [http://www.esrf.eu/Decouvrir/ Official site] * [[Large national accelerator of heavy ions|GANIL]] with [[Caen]] ([[France]]): [http://ganinfo.in2p3.fr/ Official site]. * [[Synchrotron Sun]] with [[Saint-Aubin (the Essonne)]] ([[France]]) ''' Europe ''' * [[UNILAC]] with [[GSI]] with [[Darmstadt]] ([[Germany]]) * [[DESY]] with [[Hamburg]] ([[Germany]]) * [[High-energy particle Electron Accelerator Boxing ring]] or [[HERA]] with [[Hamburg]] ([[Germany]]) * [[PETRA]] with [[Hamburg]] ([[Germany]]) * [[Broad Electron Positron]] or LEP with [[CERN]] with [[Geneva]] ([[Swiss]]) * [[Broad Collider High-energy particle]] or LHC with [[CERN]] with [[Geneva]] ([[Swiss]]) * [[AGOR cyclotron]] [[KVI]] with [[Groningen]] [[the Netherlands]] * Nuclear Research Institute Rez plc [[Czech Republic]] isochronous Cyclotron with protons Source International Atomic Energy Agency. ''' Russia and Bielorussia ''' * [[UNK]] with [[Serpukhov]] * [[VEPP]] with [[Novosibirsk]] * Joint Institute for Power and Nuclear Research, [[Minsk]] [[Bielorussia]] Generating electrostatics 250 KeV with 10 mASource International Atomic Energy Agency. * (PNPI) Petersburg Nuclear Physics Institute [[Federation of Russia]] Synchrocyclotron with protons 1000 MeV with 0,003 mASource International Atomic Energy Agency. * (ITEP) Institute for Theoretical and Experimental Physics [[Federation of Russia]] Synchrotron with protons of 2600 MeV Source International Atomic Energy Agency. ''' China: Beijing ''' * [http://www.ihep.ac.cn/english/E-Bepc/index.htm BEPC Beijing Electron Collider Positron]. Linac and storage ring 240 meters in diameter. ''' Japan ''' * [http://www.kek.jp/intra-e/ KEK High Energy Physics and Accelerator] (" Koh-Ene-Ken")in Tsukuba ([[Japan]]) Linac - * [[TRISTAN]] with [[Tokyo]] ''' Korea ''' * [[KAERI]] Korea Atomic Energy Research Institute (KAERI) [[Republic of Korea]] Accelerator linear with proton 1000 MeV, 20 my. == the abandoned failures or projects == ===ISABELLE (Intersting Storage Accelerator + Beautiful) === Storage ring and collider proton-proton which was to be operational in Brookhaven (BNL). Work started in 1978 but in 1981 the superconductive magnets were not shown as powerful as it would have been necessary. It is the delay of the development of these magnets with superconductors which brought the bankruptcy of the projet Michel Crozon, '' the Raw material - the research of the particles fundamental and their interactions '', Seuil, 1987, p 268 . The discovery in 1983 of the bosons W and Z° with the CERN decreased the attraction of the ISABELLE project then. The project is abandoned in July 1983 by the department of Energy. === Super Superconductive Collider SC === Of a circumference of 87 kilometers on a surface of Waxahachie in Texas this collider of high-energy particles, called '' Desertron '', was to transport beams of 20 TeV to contribute to the description of Boson of Higgs. Construction started in 1991 and 23,5 kilometers of tunnel were dug at the end of 1993. The American Congress decided to give up the project in 1993 because of the prohibitory cost of the realization and perhaps of the collapse of the Soviet Union. The site is currently unoccupied. This abandonment leaves its European competitor, it [[Broad Collider High-energy particle]], only in race to take up the challenge of the experimental confirmation of the existence of boson of Higgs. ===Le Vivitron of IReS=== The Nuclear research center of Strasbourg had solid experience as regards electrostatic accelerators of various energies. The last asset, with the beginning of the year 1970, was a VAN DE GRAAFF Tandem whose maximum tension had been carried to 16 million volts. The basic idea, '' a better distribution of the electric field thanks to electrodes laid out judiciously '', was built-in the project of an electrostatic accelerator, the ''' Vivitron ''', of a maximum tension of 35 million volts, in theory. The technical prowesses were promising, impressive dimensions: length of “tank” of 50 meters, diameter in the center of the tank 8,50 meters, 60 tons of SF6. Thus the belt of load had a 100 meters length and went from an end to the other of the tank. This VAN DE GRAAFF tandem differed from the largest machines of this type by its mechanical structure interns, realized starting from horizontal members big length in composite epoxy-fiber of glass and radial studs into epoxy charged with alumina. The uniform distribution of the electric field was obtained by a system of 7 gantries equipped each of 7 discrete electrodes. The studies started in 1983, the assembly between 1990 and 1993. In 1996, operation was reliable to 18 MV. The schedule of conditions was not filled, the maximum tension reached was of 25 million volts (as in the similar projects in the United States and in Great Britain). The exploitation of Vivitron ended in 2003. == accelerators of demain== === the International committee for the future accelerators === The financial problems become all the more sensitive as the size of the accelerators tends to grow démesurémentMichel Crozon, '' the Raw material - the research of the fundamental particles and their interactions '', p 327, Seuil, 1987. . Following the reflections of the ICFA (International Comitee for Future Accelerators http://www.fnal.gov/directorate/icfa/ ), several teams undertook to seek novel methods of acceleration of the particles. The science of the accelerators which was until now the prerogative of the laboratories manufacturers, is now the object of collaborations between the specialists in plasmas, those of the lasers and other branches of physics. ===Perspectives=== linear ====Accélérateurs of physics fondamentale==== The concept '' Terascale '' qualifies a physics which describes the collisions of the particles with high energies starting from TeV (10¹² eV). The LHC and Tevatron are accelerators '' Terascale ''. *L' after [[LHC]] (circular collider) is represented with [[DESY]] ('' Deutsche Elektron Synchrotron '', Germany) by the linear project of super-collider TESLA ('' Tera-Electronvolt Energy Superconducting Linear Accelerator ''), linear collider e⁺e^- entirely superconductive. The TESLA project is a 33 kilometers length linear accelerator, 21000 superconductive cavities which will function to -271 degrees, of the fields of acceleration higher than 25 MV/mètre, 500 GeV with 800 GeV of energy supplied to each collision. The boson of Higgs and the indices of the supersymmetries will be studied. *Une second way is represented by the '' project CLICK '', prepared by the CERN but late on TESLA. The linear accelerator of the CERN which will succeed the LHC, is the '' Compact LInear Collider '' (CLICK), which will use accelerating copper cavities. The CLICK project aims at an energy from 3 to 5 TeV. Its copper cavities make it possible to obtain very great accelerations of the particles, which reduces the size of the accelerator. It adopts a concept called “acceleration with two beams”, which consists in using a beam of weak energy and high intensity (beam controls) to create a beam with high energy and of low intensity (principal beam), to some extent the equivalent of an electric transformer. That remains however to be validated on the technological level. *L ''' International Linear Collider '' (ILC) is programmed by Fermilab for the years 2012-2019 (linear collider 31 km length e⁺e^-). *Le '' project X '' is a small-scale model (700 meters) of the ILC, linear accelerator with protons of 8 GeV which will be integrated into the center of the ring of [[Tevatron]]. * The American physicists (Fermilab) consider collisions of muons and neutrino factories. ====Accélérateurs synchrotrons==== Whereas one is already to the 3 {{E}} generation of machines, the technical evolution of [[synchrotron]] the S is far from being completed, of progress being awaited on the inverters, the optics of the lines of light, and the instrumentation, and in particular the detectors. Of new prospects exist in terms of machines derived from the current synchrotrons but complementary, them [[laser]] S with free electrons (LEL) http://www.jlab.org/fel/ Laser with free electrons of Jefferson Laboratory. ===Alternatives=== In these conventional structures, the accelerating field is limited to some 50 MV/m because of breakdown of the walls for more important fields. In order to reach raised energies, it is thus necessary to build gigantic structures ([[LEP]], [[LHC]] but abandonment of the SC). A possible alternative is it [[Acceleration laser-plasma|acceleration of electrons per interaction laser-plasma]]. Acceleration takes place in a medium already ionized, which eliminates the problems from breakdown. The accelerating fields are raised also definitely, which makes it possible to reduce the length of acceleration. == Références == to ==Voir aussi== ===Liens interns=== * [[Generating of VAN DE GRAAFF]] * [[Center of the linear accelerator of Stanford]] - See in particular the klystrons * [[Cyclotron]] * [[Synchrocyclotron]] * [[Synchrotron]] * [[Synchrotron radiation]] * [[Synchrotron Sun]] * [[Laboratory of the linear accelerator]] * [[Tevatron]] * [[Super Proton Synchrotron]] ''' SPS ''' * [[Broad Electron Positron]] ''' LEP ''' * [[Broad Collider High-energy particle]] ''' LHC ''' * [[List of particles]] * [[Elementary particle]] * [[Physical of the particles]] * [[List of the accelerators in physics of the particles]] * [[Particle (physical)]] * [[standard Model (physical)]] * [[National institute of nuclear physics and physics of the particles]] or IN2P3 ===Liens externes=== * [http://www.sciences.univ-nantes.fr/physique/perso/gtulloue/Meca/Charges/linac.html Principle of a linear accelerator (animation Flash)] * [http://www.sciences.univ-nantes.fr/physique/perso/gtulloue/Meca/Charges/cyclotron.html Principle of the cyclotron (animation Flash)] * {{in}} [http://ireswww.in2p3.fr/ires/recherche/vivitron/uk/welcome.html English Page of Supertandem Vivitron of Strasbourg] * {{in}} [electrostatic http://www.phy.ornl.gov/hribf/accelerator/tandemweb/ Accelerator Supertandem Pelletron] * {{in}} [http://daytona.tunl.duke.edu/pipermail/sneap/ Files of the SNEAP Symposium off Northeastern Accelerator Personal] technical Exchanges between personnel responsible for the maintenance of the accelerators. * {{in}} [http://www-adsdb.iaea.org/index.cfm Database on the accelerators] Site of [International Atomic Energy Agency (IAEA) * {{in}} [http://www.pelletron.com/ Site of the accelerators of the Pelletron type] Lists of Pelletrons (NEC) indexed. * {{in}} [http://www.highvolteng.com/ Site of accelerators HVEE] List of indexed Singletron and Tandetron. * {{in}} [http://cas.web.cern.ch/cas/Pruhonice/PDF/DC-accel-DB1.pdf cd. Accelerators] Accelerator electrostatic and with multipliers of tension. * [http://xjubier.free.fr/site_pages/CERN/CERN_LHC_ATLAS_CMS_pg01.html LHC with the CERN]. * [http://www.cea.fr/recherche_fondamentale/les_accelerateurs_de_particules particle accelerators on the site of the ECA.] * {{in}} [http://www-elsa.physik.uni-bonn.de/accelerator_list.html accelerators in the world] * {{in}} Hellborg, Ragnar, ED. '' Electrostatic Accelerators: Fundamentals and Applications '' [N.Y., N.Y.: Springer, 2005]. Available partly on line here: [http://books.google.com/books?id=tc6CEuIV1jEC&pg=PA51&lpg=PA51&dq=electrostatic+accelerator+book&source=web&ots=Qa0DbmiZJt&sig=bLoYaz_VUpBr7-Wv4lk_fLBnUo4#PPP1,M1] * [http://phototheque.in2p3.fr/albums.php Photographic library of in2P3] * {{in}} [http://www.fnal.gov/directorate/icfa/ ICFA] (International Commitee For Future Accelerators) ==Bibliography récente== Patrick Janot, “Of the giants to track the infinitely small”, '' For Science '', n°361, November 2007, p 98-104 {{physical gate}} {{Bond BA|be}} [[Category: Particle accelerator|*]] [[bg: Ускорителначастици]] [[Ca: Accelerador of partícules]] [[Cs: Urychlovač]] [[da: Partikelaccelerator]] [[of: Teilchenbeschleuniger]] [[el: Επιταχυντής σωματιδίων]] [[in: Particle accelerator]] [[be: Acelerador of partículas]] [[F: شتابدهندهذرهای]] [[fi: Hiukkaskiihdytin]] [[He: מאיץחלקיקים]] [[hu: Részecskegyorsító]] [[id: Pemercepat partikel]] [[is: Eindahraðall]] [[it: Particelle Acceleratore di]] [[ja: 加速器]] [[KB: 입자가속기]] [[it: Particularum acceleratorium]] [[lt: Dalelių greitintuvas]] [[ml: കണികാത്വരണി]] [[nl: Deeltjesversneller]] [[pl: Akcelerator cząstek]] [[Pt: Acelerador of partículas]] [[ro: Accelerator of particle]] [[Ru: Ускорительзаряженныхчастиц]] [[sk: Časticový urýchľovač]] [[SSL: Pospeševalnik]] [[sv: Partikelaccelerator]] [[tr: Parçacık hızlandırıcı]] [[ur: ذراتیمسرع]] [[VI: Máy gia tốc hạt]] [[zh: 粒子加速器
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