A microtron is a type of particle accelerator concept originating from the cyclotron in which the accelerating field is not applied through large D-shaped electrodes, but through a linear accelerator structure. The classic microtron was invented by Vladimir Veksler around 1944. [1] [2] The kinetic energy of the particles is increased by a constant amount per field change (one half or a whole revolution). Microtrons are designed to operate at constant field frequency and magnetic field in the ultrarelativistic limit. Thus they are especially suited for very light elementary particles, namely electrons.
In a microtron, due to the electrons' increasing momentum, the particle paths are different for each pass. The time needed for that is proportional to the pass number. The slow electrons need one electric field oscillation, the faster electrons need an integer multiple of this oscillation.
A racetrack microtron is a larger-scale microtron which uses two electromagnets instead of one. Both electromagnets supply a homogeneous magnetic field in a half-circle formed region, and the particles path between both magnets is thus straight. One advantage of this is that the accelerator cavity can be larger, enabling the use of different linear accelerator (linac) forms, and is not installed in a region with large magnetic fields.
The linac is placed near the edge of the gap between the dee-shaped magnets. The remainder of the gap is used for focusing devices. The electron is readmitted to the linac after each revolution. This procedure can be repeated until the increasing radius of the particle's path makes further acceleration impossible. The particle beam is then deflected into an experiment area or a further accelerator stage. The world's largest racetrack-microtron is the Mainz Microtron. [3]
Microtrons provide high-energy electron beams with a low beam emittance (no radiation equilibrium) and a high repetition rate (equal to the operation frequency of the linac).
A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying electric field. Lawrence was awarded the 1939 Nobel Prize in Physics for this invention.
A klystron is a specialized linear-beam vacuum tube, invented in 1937 by American electrical engineers Russell and Sigurd Varian, which is used as an amplifier for high radio frequencies, from UHF up into the microwave range. Low-power klystrons are used as oscillators in terrestrial microwave relay communications links, while high-power klystrons are used as output tubes in UHF television transmitters, satellite communication, radar transmitters, and to generate the drive power for modern particle accelerators.
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.
An insertion device (ID) is a component in modern synchrotron light sources, so called because they are "inserted" into accelerator tracks. They are periodic magnetic structures that stimulate highly brilliant, forward-directed synchrotron radiation emission by forcing a stored charged particle beam to perform wiggles, or undulations, as they pass through the device. This motion is caused by the Lorentz force, and it is from this oscillatory motion that we get the names for the two classes of device, which are known as wigglers and undulators. As well as creating a brighter light, some insertion devices enable tuning of the light so that different frequencies can be generated for different applications.
A dipole magnet is the simplest type of magnet. It has two poles, one north and one south. Its magnetic field lines form simple closed loops which emerge from the north pole, re-enter at the south pole, then pass through the body of the magnet. The simplest example of a dipole magnet is a bar magnet.
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.
A betatron is a type of cyclic particle accelerator for electrons. It consists of a torus-shaped vacuum chamber with an electron source. Circling the torus is an iron transformer core with a wire winding around it. The device functions similarly to a transformer, with the electrons in the torus-shaped vacuum chamber as its secondary coil. An alternating current in the primary coils accelerates electrons in the vacuum around a circular path. The betatron was the first machine capable of producing electron beams at energies higher than could be achieved with a simple electron gun, and the first circular accelerator in which particles orbited at a constant radius.
The Neutrino Factory is a type of proposed particle accelerator complex intended to measure in detail the properties of neutrinos, which are extremely weakly interacting fundamental particles that can travel in straight lines through normal matter for thousands of kilometres. The source of the neutrinos would be the decay of accelerated muons in straight sections of a storage ring. The technical issues surrounding these projects are broadly similar to those of a muon collider.
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.
Electron scattering occurs when electrons are displaced from their original trajectory. This is due to the electrostatic forces within matter interaction or, if an external magnetic field is present, the electron may be deflected by the Lorentz force. This scattering typically happens with solids such as metals, semiconductors and insulators; and is a limiting factor in integrated circuits and transistors.
The Mainz Microtron, abbreviated MAMI, is a microtron which provides a continuous wave, high intensity, polarized electron beam with an energy up to 1.6 GeV. MAMI is the core of an experimental facility for particle, nuclear and X-ray radiation physics at the Johannes Gutenberg University in Mainz (Germany). It is one of the largest campus-based accelerator facilities for basic research in Europe. The experiments at MAMI are performed by about 200 physicists of many countries organized in international collaborations.
The Alternating Gradient Synchrotron (AGS) is a particle accelerator located at the Brookhaven National Laboratory in Long Island, New York, United States.
Accelerators and Lasers In Combined Experiments (ALICE), or Energy Recovery Linac Prototype (ERLP) is a 35MeV energy recovery linac test facility at Daresbury Laboratory in Cheshire, England. The project was originally conceived as a test bed for the 4th Generation Light Source (4GLS), and consists of:
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies to contain them in well-defined beams. Small accelerators are used for fundamental research in particle physics. Accelerators are also used as synchrotron light sources for the study of condensed matter physics. Smaller particle accelerators are used in a wide variety of applications, including particle therapy for oncological purposes, radioisotope production for medical diagnostics, ion implanters for the manufacture of semiconductors, and accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating, typically for many hours. Storage of a particular particle depends upon the mass, momentum, and usually the charge of the particle to be stored. Storage rings most commonly store electrons, positrons, or protons.
Vladimir Aleksandrovich Teplyakov was a Russian experimental physicist known for his work on particle accelerators. Together with I.M. Kapchinsky, he invented the principle of the radio-frequency quadrupole (RFQ), which revolutionized the acceleration of low-energy charged particle beams.
A Fixed-Field alternating gradient Accelerator is a circular particle accelerator concept that can be characterized by its time-independent magnetic fields and the use of alternating gradient strong focusing.
In accelerator physics, a magnetic lattice is a composition of electromagnets at given longitudinal positions around the vacuum tube of a particle accelerator, and thus along the path of the enclosed charged particle beam. The lattice properties have a large influence on the properties of the particle beam, which is shaped by magnetic fields. Lattices can be closed, linear and are also used at interconnects between different accelerator structures.
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. First proposed in 1965 the idea gained interest since the early 2000s.
In a medical facility, such as a hospital or clinic, a gantry holds radiation detectors and/or a radiation source used to diagnose or treat a patient's illness. Radiation sources may produce gamma radiation, x-rays, electromagnetic radiation, or magnetic fields depending on the purpose of the device.