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Strong Focusing
In accelerator physics strong focusing or alternating-gradient focusing is the principle that, using sets of multiple electromagnets, it is possible to make a particle beam simultaneously converge in both directions perpendicular to the direction of travel. By contrast, weak focusing is the principle that nearby circles, described by charged particles moving in a uniform magnetic field, only intersect once per revolution. Earnshaw's theorem shows that simultaneous focusing in two directions transverse to the beam axis at once by a single magnet is impossible - a magnet which focuses in one direction will defocus in the perpendicular direction. However, iron "poles" of a cyclotron or two or more spaced quadrupole magnets (arranged in quadrature) can alternately focus horizontally and vertically, and the net overall effect of a combination of these can be adjusted to focus the beam in both directions. Strong focusing was first conceived by Nicholas Christofilos in 1949 but not pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aust
Aust is a small village in South Gloucestershire, England, about north of Bristol and about south west of Gloucester. It is located on the eastern side of the Severn estuary, close to the eastern end of the Severn Bridge which carries the M48 motorway. The village has a chapel, a church and a public house. There is a large area of farmland on the river bank, which is sometimes flooded due to the high tidal range of the Severn. Aust Cliff, above the Severn, is located about from the village. The civil parish of Aust includes the villages of Elberton and Littleton-upon-Severn. History Overview Aust, on the River Severn, was at one end of an ancient Roman road that let to Cirencester. Its name, Aust, may be one of the very few English place-names to be derived from the Latin ''Augusta''. The name of Aust is recorded in 793 or 794 as ''Austan'' (''terram aet Austan v manentes'') when it was returned to the Church of Worcester after having been taken by King Offa's earl, Bynna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hartland Snyder
Hartland Sweet Snyder (1913, Salt Lake City – 1962) was an American physicist who along with Robert Oppenheimer calculated the gravitational collapse of a pressure-free sphere of dust particles as described by Einstein's general relativity, and found they contracted onto a radial distance, the Schwarzschild radius. It was later interpreted as the particles ending in the particles disappearing beneath the 'event horizon' associated with a Black Hole singularity. In recent years, it was shown by Trevor Marshall that the particle trajectories end in a shell of infinite density at the 'event horizon' radius, supporting the shell collapsar as endpoint. Snyder’s argument that the “star thus tends to close itself off from any communication with a distant observer” which is quoted as an early inference of a Black Hole, does not follow from his model. Only the very surface of the infinite density shell could reflect or emit radiation and solutions without a density singularity are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Gun
An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode-ray tubes (CRTs), used in nearly all television sets, computer displays and oscilloscopes that are not flat-panel displays. They are also used in field-emission displays (FEDs), which are essentially flat-panel displays made out of rows of extremely small cathode-ray tubes. They are also used in microwave linear beam vacuum tubes such as klystrons, inductive output tubes, travelling wave tubes, and gyrotrons, as well as in scientific instruments such as electron microscopes and particle accelerators. Electron guns may be classified by the type of electric field generation (DC or RF), by emission mechanism (thermionic, photocathode, cold emission, plasmas source), by focusing (pure electrostatic or with magnetic fields), or by the number of electrodes. Characteristics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ray Transfer Matrix Analysis
Ray transfer matrix analysis (also known as ABCD matrix analysis) is a mathematical form for performing ray tracing calculations in sufficiently simple problems which can be solved considering only paraxial rays. Each optical element (surface, interface, mirror, or beam travel) is described by a 2×2 ''ray transfer matrix'' which operates on a vector describing an incoming light ray to calculate the outgoing ray. Multiplication of the successive matrices thus yields a concise ray transfer matrix describing the entire optical system. The same mathematics is also used in accelerator physics to track particles through the magnet installations of a particle accelerator, see electron optics. This technique, as described below, is derived using the ''paraxial approximation'', which requires that all ray directions (directions normal to the wavefronts) are at small angles ''θ'' relative to the optical axis of the system, such that the approximation \sin \theta \approx \theta remains val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextupole Magnet
A sextupole magnet (also known as a hexapole magnet) consist of six magnetic poles set out in an arrangement of alternating north and south poles arranged around an axis. They are used in particle accelerators for the control of chromatic aberrations and for damping the head tail instability. Two sets of sextupole magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...s are used in transmission electron microscopy, transmission electron microscopes to correct for spherical aberration. The design of sextupoles using electromagnets generally involves six steel pole tips of alternating polarity. The steel is magnetised by a large electric current that flows in the coils of wire wrapped around the poles. The coils may be formed from hollow copper magnet wire that carry coolant, usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternating Gradient Synchrotron
The Alternating Gradient Synchrotron (AGS) is a particle accelerator located at the Brookhaven National Laboratory in Long Island, New York, United States. The Alternating Gradient Synchrotron was built on the innovative concept of the alternating gradient, or strong-focusing principle, developed by Brookhaven physicists. This new concept in accelerator design allowed scientists to accelerate protons to energies that were previously unachievable. The AGS became the world's premiere accelerator when it reached its design energy of 33 billion electron volts (GeV) on July 29, 1960. Until 1968, the AGS was the highest energy accelerator in the world, slightly higher than its 28 GeV sister machine, the Proton Synchrotron at CERN, the European laboratory for high-energy physics. While 21st century accelerators can reach energies in the trillion electron volt region, the AGS earned researchers three Nobel Prizes and today serves as the injector for Brookhaven's Relativistic Heavy Ion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review
''Physical Review'' is a peer-reviewed scientific journal established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical Society (APS). The journal is in its third series, and is split in several sub-journals each covering a particular field of physics. It has a sister journal, ''Physical Review Letters'', which publishes shorter articles of broader interest. History ''Physical Review'' commenced publication in July 1893, organized by Cornell University professor Edward Nichols and helped by the new president of Cornell, J. Gould Schurman. The journal was managed and edited at Cornell in upstate New York from 1893 to 1913 by Nichols, Ernest Merritt, and Frederick Bedell. The 33 volumes published during this time constitute ''Physical Review Series I''. The American Physical Society (APS), founded in 1899, took over its publication in 1913 and star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brookhaven National Laboratory
Brookhaven National Laboratory (BNL) is a United States Department of Energy national laboratory located in Upton, Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base and Japanese internment camp. Its name stems from its location within the Town of Brookhaven, approximately 60 miles east of New York City. It is managed by Stony Brook University and Battelle Memorial Institute. Research at BNL includes nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience, and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider and National Synchrotron Light Source II. Seven Nobel Prizes have been awarded for work conducted at Brookhaven Lab. Overview BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernest Courant
Ernest Courant (March 26, 1920 – April 21, 2020) was an American accelerator physicist and a fundamental contributor to modern large-scale particle accelerator concepts. His most notable discovery was his 1952 work with Milton S. Livingston and Hartland Snyder on the Strong focusing principle, a critical step in the development of modern particle accelerators like the synchrotron, though this work was preceded by that of Nicholas Christofilos. Courant was a member of the National Academy of Sciences, and remained active as a distinguished scientist emeritus at Brookhaven National Laboratory. He played a part in the work of Brookhaven for sixty years and had also been mentor to several generations of students. In this kind of generative academic influence, he can be compared to his father, the mathematician Richard Courant. He turned 100 in March 2020 and died the following month. Early life Courant was born March 26, 1920 in Göttingen, Germany, the first of four children ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerator Physics
Accelerator physics is a branch of applied physics, concerned with designing, building and operating particle accelerators. As such, it can be described as the study of motion, manipulation and observation of relativistic charged particle beams and their interaction with accelerator structures by electromagnetic fields. It is also related to other fields: *Microwave engineering (for acceleration/deflection structures in the radio frequency range). *Optics with an emphasis on geometrical optics (beam focusing and bending) and laser physics (laser-particle interaction). *Computer technology with an emphasis on digital signal processing; e.g., for automated manipulation of the particle beam. *Plasma physics, for the description of intense beams. The experiments conducted with particle accelerators are not regarded as part of accelerator physics, but belong (according to the objectives of the experiments) to, e.g., particle physics, nuclear physics, condensed matter physics or m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicholas Christofilos
Nicholas Constantine Christofilos ( el, Νικόλαος Χριστοφίλου; December 16, 1916 – September 24, 1972) was a Greek physicist. The Christofilos effect, a type of electromagnetic shielding, is named after him. Career Christofilos was born in Boston, Massachusetts and raised in Greece. He attended the National Technical University of Athens at age 18, and graduated with a degree in Electrical and Mechanical Engineering in 1938. He remained in Greece during World War II, working for an Athens elevator maintenance company during the Nazi occupation. He later founded his own elevator company. During all of this, he maintained an amateur interest in accelerator physics and high-energy particle physics, and studied German and American texts on the subjects extensively. In 1946 he independently developed ideas for a synchrotron and in 1949 he conceived the strong-focusing principle. Rather than publishing in a journal he submitted a patent application in the US an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
