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Intersecting Storage Rings
The ISR (standing for "Intersecting Storage Rings") was a particle accelerator at CERN. It was the world's first hadron collider, and ran from 1971 to 1984, with a maximum center of mass energy of 62 GeV. From its initial startup, the collider itself had the capability to produce particles like the J/ψ and the upsilon, as well as observable jet structure; however, the particle detector experiments were not configured to observe events with large momentum transverse to the beamline, leaving these discoveries to be made at other experiments in the mid-1970s. Nevertheless, the construction of the ISR involved many advances in accelerator physics, including the first use of stochastic cooling, and it held the record for luminosity at a hadron collider until surpassed by the Tevatron in 2004. History The ISR was proposed in 1964 for conducting the head-on proton-proton collisions at a beam energy of 28 GeV; to the study of the new particles created in such collisions.&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISR Surface
ISR may refer to: Organizations * Institute for Strategy and Reconciliation, a think tank, relief and development organization * Institutional and Scientific Relations, a Directorate of the European Commission * International Star Registry, a company which publishes the book ''Your Place in the Cosmos'' * Institute for Social Research – CSUS, affiliated with California State University, Sacramento * International School on the Rhein, one of the top IB schools in Germany Publications * ''ISR'', a monthly socialist magazine published from 1900 until 1918 * ''Information Systems Research'', an academic journal in the information systems discipline * ''International Socialist Review'' (other), any of several U.S. publications * ''International Statistical Review'', a journal of the International Statistical Institute * ''International Studies Review'', an academic journal of the International Studies Association * ''Israel Studies Review'', an academic journal of the Ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity (scattering Theory)
In scattering theory and accelerator physics, luminosity (''L'') is the ratio of the number of events detected (''dN'') in a certain period of time (''dt'') to the cross-section (''σ''): : L = \frac\frac. It has the dimensions of events per time per area, and is usually expressed in the cgs units of cm−2· s−1 or the non-SI units of b−1·s−1. In practice, ''L'' is dependent on the particle beam parameters, such as beam width and particle flow rate, as well as the target properties, such as target size and density. A related quantity is integrated luminosity (''L''int), which is the integral of the luminosity with respect to time: : L_\mathrm = \int L \ dt. The luminosity and integrated luminosity are useful values to characterize the performance of a particle accelerator. In particular, all collider experiments aim to maximize their integrated luminosities, as the higher the integrated luminosity, the more data is available to analyze. Examples of collider l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiproton
The antiproton, , (pronounced ''p-bar'') is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived, since any collision with a proton will cause both particles to be annihilated in a burst of energy. The existence of the antiproton with electric charge of , opposite to the electric charge of of the proton, was predicted by Paul Dirac in his 1933 Nobel Prize lecture. Dirac received the Nobel Prize for his 1928 publication of his Dirac equation that predicted the existence of positive and negative solutions to Einstein's energy equation (E = mc^2) and the existence of the positron, the antimatter analog of the electron, with opposite charge and spin. The antiproton was first experimentally confirmed in 1955 at the Bevatron particle accelerator by University of California, Berkeley physicists Emilio Segrè and Owen Chamberlain, for which they were awarded the 1959 Nobel Prize in Physics. In terms of valence quarks, an antiproton consists o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Particle
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways. Alpha particles are named after the first letter in the Greek alphabet, α. The symbol for the alpha particle is α or α2+. Because they are identical to helium nuclei, they are also sometimes written as or indicating a helium ion with a +2 charge (missing its two electrons). Once the ion gains electrons from its environment, the alpha particle becomes a normal (electrically neutral) helium atom . Alpha particles have a net spin of zero. Due to the mechanism of their production in standard alpha radioactive decay, alpha particles generally have a kinetic energy of about 5 MeV, and a velocity in the vicinity of 4% of the speed of light. (See discussion below for the limits of these figures in alpha decay.) T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deuteron
Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium atom, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutrons in the nucleus. Deuterium has a natural abundance in Earth's oceans of about one atom of deuterium among all atoms of hydrogen (see heavy water). Thus deuterium accounts for approximately 0.0156% by number (0.0312% by mass) of all the naturally occurring hydrogen in the oceans, while protium accounts for more than 99.98%. The abundance of deuterium changes slightly from one kind of natural water to another (see Vienna Standard Mean Ocean Water). (Tritium is yet another hydrogen isotope, with two neutrons, that is far more rare and is radioactive.) The name ''deuterium'' is derived from the Greek , meaning "second", to denot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CERN Proton Synchrotron
The Proton Synchrotron (PS, sometimes also referred to as CPS) 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. Today, the PS is part of CERN's accelerator complex. It accelerates protons for the LHC as well as a number of other experimental facilities at CERN. Using a negative hydrogen ion source, the ions are first accelerated to the energy of 160 MeV in the linear accelerator Linac 4. The hydrogen ion is then stripped of both electrons, leaving only the nucleus containing one proton, which is injected into the Proton Sync ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proton Synchrotron
The Proton Synchrotron (PS, sometimes also referred to as CPS) 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. Today, the PS is part of CERN's accelerator complex. It accelerates protons for the LHC as well as a number of other experimental facilities at CERN. Using a negative hydrogen ion source, the ions are first accelerated to the energy of 160 MeV in the linear accelerator Linac 4. The hydrogen ion is then stripped of both electrons, leaving only the nucleus containing one proton, which is injected into the Proton Synchrotron B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Acceleration
Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons, and ions, using the electric field associated with electron plasma wave or other high-gradient plasma structures (like shock and sheath fields). The plasma acceleration structures are created either using ultra-short laser pulses or energetic particle beams that are matched to the plasma parameters. These techniques offer a way to build high performance particle accelerators of much smaller size than conventional devices. The basic concepts of plasma acceleration and its possibilities were originally conceived by Toshiki Tajima and John M. Dawson of UCLA in 1979. The initial experimental designs for a "wakefield" accelerator were conceived at UCLA by Chandrashekhar J. Joshi et al. Current experimental devices show accelerating gradients several orders of magnitude better than current particle accelerators over very short distances, and about one order of magnitude better (1 GeV ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed-field Alternating Gradient Accelerator
A Fixed-Field alternating gradient Accelerator (FFA; also abbreviated FFAG) is a circular particle accelerator concept that can be characterized by its time-independent magnetic fields (''fixed-field'', like in a cyclotron) and the use of alternating gradient strong focusing (as in a synchrotron). In all circular accelerators, magnetic fields are used to bend the particle beam. Since the magnetic force required to bend the beam increases with particle energy, as the particles accelerate, either their paths will increase in size, or the magnetic field must be increased over time to hold the particles in a constant size orbit. Fixed-field machines, such as cyclotrons and FFAs, use the former approach and allow the particle path to change with acceleration. In order to keep particles confined to a beam, some type of focusing is required. Small variations in the shape of the magnetic field, while maintaining the same overall field direction, are known as weak focusing. Strong, or al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conductors can radiate into space as electromagnetic waves ( radio waves). This is the basis of radio technology. * RF current does not penetrate deeply into electrica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Of Mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe. In the case of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five major unincorporated territories, nine United States Minor Outlying Islands, Minor Outlying Islands, and 326 Indian reservations. The United States is also in Compact of Free Association, free association with three Oceania, Pacific Island Sovereign state, sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Palau, Republic of Palau. It is the world's List of countries and dependencies by area, third-largest country by both land and total area. It shares land borders Canada–United States border, with Canada to its north and Mexico–United States border, with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
