Owen Chamberlain was an American physicist, Nobel laureate in physics for his discovery, with collaborator Emilio Segrè, of the antiproton, a sub-atomic antiparticle. Born in San Francisco, Chamberlain graduated from Germantown Friends School in Philadelphia in 1937, he studied physics at Dartmouth College, where he was a member of Alpha Theta chapter of Theta Chi Fraternity, at the University of California, Berkeley. He remained in school until the start of World War II, joined the Manhattan Project in 1942, where he worked with Segrè, both at Berkeley and in Los Alamos, New Mexico, he married Beatrice Babette Copper in 1943, with. In 1946, after the war, Chamberlain continued with his doctoral studies at the University of Chicago under physicist Enrico Fermi. Fermi acted as an important guide and mentor for Chamberlain, encouraging him to leave behind theoretical physics for experimental physics, for which Chamberlain had a particular aptitude. Chamberlain received his Ph. D. from the University of Chicago in 1949.
In 1948, having completed his experimental work, Chamberlain returned to Berkeley as a member of its faculty. There he, Segrè, other physicists investigated proton-proton scattering. In 1955, a series of proton scattering experiments at Berkeley's Bevatron led to the discovery of the anti-proton, a particle like a proton but negatively charged. Chamberlain's research work included the time projection chamber, work at the Stanford Linear Accelerator Center. Chamberlain was politically active on issues of peace and social justice, outspoken against the Vietnam War, he was a member of Scientists for Sakharov and Shcharansky, three physicists of the former Soviet Union imprisoned for their political beliefs. In the 1980s, he helped found the nuclear freeze movement. In 2003 he was one of 22 Nobel Laureates. Chamberlain was diagnosed with Parkinson's disease in 1985, retired from teaching in 1989, he died of complications from the disease on February 28, 2006, in Berkeley at the age of 85. Chamberlain plays a central role in Jacob M. Appel's Sherwood Anderson Award-winning short story, "Measures of Sorrow".
Chamberlain, Owen. Of Antiprotons, Radiation Laboratory University of California predecessor to the Ernest Orlando Lawrence Berkeley National Laboratory, United States Atomic Energy Commission predecessor to the U. S. Department of Energy. Chamberlain, Owen. S. Department of Energy. Chamberlain, Owen. Experiments on Antiprotons: Antiproton-Nucleon Cross Sections, Radiation Laboratory University of California predecessor to the Ernest Orlando Lawrence Berkeley National Laboratory, United States Atomic Energy Commission predecessor to the U. S. Department of Energy. Chamberlain, O; the Early Antiproton Work, Radiation Laboratory University of California predecessor to the Ernest Orlando Lawrence Berkeley National Laboratory, United States Atomic Energy Commission predecessor to the U. S. Department of Energy. Chamberlain, O. Personal History of Nucleon Polarization Experiments, Lawrence Berkeley Laboratory predecessor to the Ernest Orlando Lawrence Berkeley National Laboratory, U. S. Department of Energy.
Owen Chamberlain The Nobel Prize in Physics 1959 Short Bio at Berkeley Guide to the Owen Chamberlain Papers at The Bancroft Library New York Times obituary National Academy of Sciences Biographical Memoir
The magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include: loops of electric current, permanent magnets, elementary particles, various molecules, many astronomical objects. More the term magnetic moment refers to a system's magnetic dipole moment, the component of the magnetic moment that can be represented by an equivalent magnetic dipole: a magnetic north and south pole separated by a small distance; the magnetic dipole component is sufficient for large enough distances. Higher order terms may be needed in addition to the dipole moment for extended objects; the magnetic dipole moment of an object is defined in terms of the torque that object experiences in a given magnetic field. The same applied magnetic field creates larger torques on objects with larger magnetic moments; the strength of this torque depends not only on the magnitude of the magnetic moment but on its orientation relative to the direction of the magnetic field.
The magnetic moment may be considered, therefore. The direction of the magnetic moment points from the south to north pole of the magnet; the magnetic field of a magnetic dipole is proportional to its magnetic dipole moment. The dipole component of an object's magnetic field is symmetric about the direction of its magnetic dipole moment, decreases as the inverse cube of the distance from the object; the magnetic moment can be defined as a vector relating the aligning torque on the object from an externally applied magnetic field to the field vector itself. The relationship is given by: τ = m × B where τ is the torque acting on the dipole, B is the external magnetic field, m is the magnetic moment; this definition is based on how one could, in principle, measure the magnetic moment of an unknown sample. For a current loop, this definition leads to the magnitude of the magnetic dipole moment equaling the product of the current times the area of the loop. Further, this definition allows the calculation of the expected magnetic moment for any known macroscopic current distribution.
An alternative definition is useful for thermodynamics calculations of the magnetic moment. In this definition, the magnetic dipole moment of a system is the negative gradient of its intrinsic energy, with respect to external magnetic field: m = − x ^ ∂ U i n t ∂ B x − y ^ ∂ U i n t ∂ B y − z ^ ∂ U i n t ∂ B z. Generically, the intrinsic energy includes the self-field energy of the system plus the energy of the internal workings of the system. For example, for a hydrogen atom in a 2p state in an external field, the self-field energy is negligible, so the internal energy is the eigenenergy of the 2p state, which includes Coulomb potential energy and the kinetic energy of the electron; the interaction-field energy between the internal dipoles and external fields is not part of this internal energy. The unit for magnetic moment in International System of Units base units is A⋅m2, where A is ampere and m is meter; this unit has equivalents in other SI derived units including: A ⋅ m 2 = N ⋅ m T = J T, where N is newton, T is tesla, J is joule.
Although torque and energy are dimensionally equivalent, torques are never expressed in units of energy. In the CGS system, there are several different sets of electromagnetism units, of which the main ones are ESU, EMU. Among these, there are two alternative units of magnetic dipole moment: 1 statA ⋅ cm 2 = 3.33564095 × 10 − 14 A ⋅ m 2 1 erg G = 10 − 3 A ⋅ m 2,where statA is statamperes, cm is centimeters, erg is ergs, G is gauss. The ratio of these two non-equivalent CGS units is equal to the speed of light in free space, expressed in cm⋅s−1. All formula
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists are interested in the root or ultimate causes of phenomena, frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole; the field includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies; the study and practice of physics is based on an intellectual ladder of discoveries and insights from ancient times to the present.
Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture, for example in the work of Euclid, Thales of Miletus and Aristarchus. Roots emerged in ancient Asian culture and in the Islamic medieval period, for example the work of Alhazen in the 11th century; the modern scientific worldview and the bulk of physics education can be said to flow from the scientific revolution in Europe, starting with the work of Galileo Galilei and Johannes Kepler in the early 1600s. Newton's laws of motion and Newton's law of universal gravitation were formulated in the 17th century; the experimental discoveries of Faraday and the theory of Maxwell's equations of electromagnetism were developmental high points during the 19th century. Many physicists contributed to the development of quantum mechanics in the early-to-mid 20th century. New knowledge in the early 21st century includes a large increase in understanding physical cosmology; the broad and general study of nature, natural philosophy, was divided into several fields in the 19th century, when the concept of "science" received its modern shape.
Specific categories emerged, such as "biology" and "biologist", "physics" and "physicist", "chemistry" and "chemist", among other technical fields and titles. The term physicist was coined by William Whewell in his 1840 book The Philosophy of the Inductive Sciences. A standard undergraduate physics curriculum consists of classical mechanics and magnetism, non-relativistic quantum mechanics, statistical mechanics and thermodynamics, laboratory experience. Physics students need training in mathematics, in computer science. Any physics-oriented career position requires at least an undergraduate degree in physics or applied physics, while career options widen with a Master's degree like MSc, MPhil, MPhys or MSci. For research-oriented careers, students work toward a doctoral degree specializing in a particular field. Fields of specialization include experimental and theoretical astrophysics, atomic physics, biological physics, chemical physics, condensed matter physics, geophysics, gravitational physics, material science, medical physics, molecular physics, nuclear physics, radiophysics, electromagnetic field and microwave physics, particle physics, plasma physics.
The highest honor awarded to physicists is the Nobel Prize in Physics, awarded since 1901 by the Royal Swedish Academy of Sciences. National physics professional societies have many awards for professional recognition. In the case of the American Physical Society, as of 2017, there are 33 separate prizes and 38 separate awards in the field; the three major employers of career physicists are academic institutions and private industries, with the largest employer being the last. Physicists in academia or government labs tend to have titles such as Assistants, Professors, Sr./Jr. Scientist, or postdocs; as per the American Institute of Physics, some 20% of new physics Ph. D.s holds jobs in engineering development programs, while 14% turn to computer software and about 11% are in business/education. A majority of physicists employed apply their skills and training to interdisciplinary sectors. Job titles for graduate physicists include Agricultural Scientist, Air Traffic Controller, Computer Programmer, Electrical Engineer, Environmental Analyst, Medical Physicist, Oceanographer, Physics Teacher/Professor/Researcher, Research Scientist, Reactor Physicist, Engineering Physicist, Satellite Missions Analyst, Science Writer, Software Engineer, Systems Engineer, Microelectronics Engineer, Radar Developer, Technical Consultant, etc.
A majority of Physics terminal bachelor's degree holders are employed in the private sector. Other fields are academia and military service, nonprofit entities and teaching. Typical duties of physicists with master's and doctoral degrees working in their domain involve research and analysis, data preparation, instrumentation and development of industrial or medical equipment and software development, etc. Chartered Physicist is a chartered status and a professional qualification awarded by the Institute of Physics, it is denoted by the postnominals "CPhys". Achieving chartered status in any profession denotes to the wider community a high level of specialised subject knowledge and professional competence. According to the Institute of Physics, holders of the award of the Chartered Physicist demonst
University of California, Berkeley
The University of California, Berkeley is a public research university in Berkeley, California. It was founded in 1868 and serves as the flagship institution of the ten research universities affiliated with the University of California system. Berkeley has since grown to instruct over 40,000 students in 350 undergraduate and graduate degree programs covering numerous disciplines. Berkeley is one of the 14 founding members of the Association of American Universities, with $789 million in R&D expenditures in the fiscal year ending June 30, 2015. Today, Berkeley maintains close relationships with three United States Department of Energy National Laboratories—Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory and Los Alamos National Laboratory—and is home to many institutes, including the Mathematical Sciences Research Institute and the Space Sciences Laboratory. Through its partner institution University of California, San Francisco, Berkeley offers a joint medical program at the UCSF Medical Center.
As of October 2018, Berkeley alumni, faculty members and researchers include 107 Nobel laureates, 25 Turing Award winners, 14 Fields Medalists. They have won 9 Wolf Prizes, 45 MacArthur Fellowships, 20 Academy Awards, 14 Pulitzer Prizes and 207 Olympic medals. In 1930, Ernest Lawrence invented the cyclotron at Berkeley, based on which UC Berkeley researchers along with Berkeley Lab have discovered or co-discovered 16 chemical elements of the periodic table – more than any other university in the world. During the 1940s, Berkeley physicist J. R. Oppenheimer, the "Father of the Atomic Bomb," led the Manhattan project to create the first atomic bomb. In the 1960s, Berkeley was noted for the Free Speech Movement as well as the Anti-Vietnam War Movement led by its students. In the 21st century, Berkeley has become one of the leading universities in producing entrepreneurs and its alumni have founded a large number of companies worldwide. Berkeley is ranked among the top 20 universities in the world by the Academic Ranking of World Universities, the Times Higher Education World University Rankings, the U.
S. News & World Report Global University Rankings, it is considered one of the "Public Ivies", meaning that it is a public university thought to offer a quality of education comparable to that of the Ivy League. In 1866, the private College of California purchased the land comprising the current Berkeley campus in order to re-sell it in subdivided lots to raise funds; the effort failed to raise the necessary funds, so the private college merged with the state-run Agricultural and Mechanical Arts College to form the University of California, the first full-curriculum public university in the state. Upon its founding, The Dwinelle Bill stated that the "University shall have for its design, to provide instruction and thorough and complete education in all departments of science and art, industrial and professional pursuits, general education, special courses of instruction in preparation for the professions". Ten faculty members and 40 students made up the new University of California when it opened in Oakland in 1869.
Frederick H. Billings was a trustee of the College of California and suggested that the new site for the college north of Oakland be named in honor of the Anglo-Irish philosopher George Berkeley. In 1870, Henry Durant, the founder of the College of California, became the first president. With the completion of North and South Halls in 1873, the university relocated to its Berkeley location with 167 male and 22 female students where it held its first classes. Beginning in 1891, Phoebe Apperson Hearst made several large gifts to Berkeley, funding a number of programs and new buildings and sponsoring, in 1898, an international competition in Antwerp, where French architect Émile Bénard submitted the winning design for a campus master plan. In 1905, the University Farm was established near Sacramento becoming the University of California, Davis. In 1919, Los Angeles State Normal School became the southern branch of the University, which became University of California, Los Angeles. By 1920s, the number of campus buildings had grown and included twenty structures designed by architect John Galen Howard.
Robert Gordon Sproul served as president from 1930 to 1958. In the 1930s, Ernest Lawrence helped establish the Radiation Laboratory and invented the cyclotron, which won him the Nobel physics prize in 1939. Based on the cyclotron, UC Berkeley scientists and researchers, along with Berkeley Lab, went on to discover 16 chemical elements of the periodic table – more than any other university in the world. In particular, during World War II and following Glenn Seaborg's then-secret discovery of plutonium, Ernest Orlando Lawrence's Radiation Laboratory began to contract with the U. S. Army to develop the atomic bomb. UC Berkeley physics professor J. Robert Oppenheimer was named scientific head of the Manhattan Project in 1942. Along with the Lawrence Berkeley National Laboratory, Berkeley was a partner in managing two other labs, Los Alamos National Laboratory and Lawrence Livermore National Laboratory. By 1942, the American Council on Education ranked Berkeley second only to Harvard in the number of distinguished departments.
During the McCarthy era in 1949, the Board of Regents adopted an anti-communist loyalty oath. A number of faculty members led by Edward C. Tolman were dismissed. In 1952, the University of California became; each campus was give
In physics, the electronvolt is a unit of energy equal to 1.6×10−19 joules in SI units. The electronvolt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences, because a particle with electric charge q has an energy E = qV after passing through the potential V. Like the elementary charge on which it is based, it is not an independent quantity but is equal to 1 J/C √2hα / μ0c0, it is a common unit of energy within physics used in solid state, atomic and particle physics. It is used with the metric prefixes milli-, kilo-, mega-, giga-, tera-, peta- or exa-. In some older documents, in the name Bevatron, the symbol BeV is used, which stands for billion electronvolts. An electronvolt is the amount of kinetic energy gained or lost by a single electron accelerating from rest through an electric potential difference of one volt in vacuum. Hence, it has a value of one volt, 1 J/C, multiplied by the electron's elementary charge e, 1.6021766208×10−19 C.
Therefore, one electronvolt is equal to 1.6021766208×10−19 J. The electronvolt, as opposed to volt, is not an SI unit, its derivation is empirical, which means its value in SI units must be obtained by experiment and is therefore not known unlike the litre, the light-year and such other non-SI units. Electronvolt is a unit of energy; the SI unit for energy is joule. 1 eV is equal to 1.6021766208×10−19 J. By mass–energy equivalence, the electronvolt is a unit of mass, it is common in particle physics, where units of mass and energy are interchanged, to express mass in units of eV/c2, where c is the speed of light in vacuum. It is common to express mass in terms of "eV" as a unit of mass using a system of natural units with c set to 1; the mass equivalent of 1 eV/c2 is 1 eV / c 2 = ⋅ 1 V 2 = 1.783 × 10 − 36 kg. For example, an electron and a positron, each with a mass of 0.511 MeV/c2, can annihilate to yield 1.022 MeV of energy. The proton has a mass of 0.938 GeV/c2. In general, the masses of all hadrons are of the order of 1 GeV/c2, which makes the GeV a convenient unit of mass for particle physics: 1 GeV/c2 = 1.783×10−27 kg.
The unified atomic mass unit, 1 gram divided by Avogadro's number, is the mass of a hydrogen atom, the mass of the proton. To convert to megaelectronvolts, use the formula: 1 u = 931.4941 MeV/c2 = 0.9314941 GeV/c2. In high-energy physics, the electronvolt is used as a unit of momentum. A potential difference of 1 volt causes an electron to gain an amount of energy; this gives rise to usage of eV as units of momentum, for the energy supplied results in acceleration of the particle. The dimensions of momentum units are LMT−1; the dimensions of energy units are L2MT−2. Dividing the units of energy by a fundamental constant that has units of velocity, facilitates the required conversion of using energy units to describe momentum. In the field of high-energy particle physics, the fundamental velocity unit is the speed of light in vacuum c. By dividing energy in eV by the speed of light, one can describe the momentum of an electron in units of eV/c; the fundamental velocity constant c is dropped from the units of momentum by way of defining units of length such that the value of c is unity.
For example, if the momentum p of an electron is said to be 1 GeV the conversion to MKS can be achieved by: p = 1 GeV / c = ⋅ ⋅ = 5.344286 × 10 − 19 kg ⋅ m / s. In particle physics, a system of "natural units" in which the speed of light in vacuum c and the reduced Planck constant ħ are dimensionless and equal to unity is used: c = ħ = 1. In these units, both distances and times are expressed in inverse energy units (while energy and mass are expressed in the same units, see mas
A cloud chamber known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic charged particle interacts with the gaseous mixture by knocking electrons off gas molecules via electrostatic forces during collisions, resulting in a trail of ionized gas particles; the resulting ions act as condensation centers around which a mist-like trail of small droplets form if the gas mixture is at the point of condensation. These droplets are visible as a "cloud" track that persist for several seconds while the droplets fall through the vapor; these tracks have characteristic shapes. For example, an alpha particle track is thick and straight, while an electron track is wispy and shows more evidence of deflections by collisions. Cloud chambers played a prominent role in the experimental particle physics from the 1920s to the 1950s, until the advent of the bubble chamber.
In particular, the discoveries of the positron in 1932 and the muon in 1936, both by Carl Anderson, used cloud chambers. Discovery of the kaon by George Rochester and Clifford Charles Butler in 1947 was made using a cloud chamber as the detector.. In each case, cosmic rays were the source of ionizing radiation. Charles Thomson Rees Wilson, a Scottish physicist, is credited with inventing the cloud chamber. Inspired by sightings of the Brocken spectre while working on the summit of Ben Nevis in 1894, he began to develop expansion chambers for studying cloud formation and optical phenomena in moist air, he discovered that ions could act as centers for water droplet formation in such chambers. He pursued the application of this discovery and perfected the first cloud chamber in 1911. In Wilson's original chamber the air inside the sealed device was saturated with water vapor a diaphragm was used to expand the air inside the chamber, cooling the air and starting to condense water vapor. Hence the name expansion cloud chamber is used.
When an ionizing particle passes through the chamber, water vapor condenses on the resulting ions and the trail of the particle is visible in the vapor cloud. Wilson, along with Arthur Compton, received the Nobel Prize in Physics in 1927 for his work on the cloud chamber; this kind of chamber is called a pulsed chamber because the conditions for operation are not continuously maintained. Further developments were made by Patrick Blackett who utilised a stiff spring to expand and compress the chamber rapidly, making the chamber sensitive to particles several times a second. A cine film was used to record the images; the diffusion cloud chamber was developed in 1936 by Alexander Langsdorf. This chamber differs from the expansion cloud chamber in that it is continuously sensitized to radiation, in that the bottom must be cooled to a rather low temperature colder than −26 °C. Instead of water vapor, alcohol is used because of its lower freezing point. Cloud chambers cooled by dry ice or Peltier effect thermoelectric cooling are common demonstration and hobbyist devices.
Diffusion-type cloud chambers will be discussed here. A simple cloud chamber consists of a warm top plate and a cold bottom plate, it requires a source of liquid alcohol at the warm side of the chamber where the liquid evaporates, forming a vapor that cools as it falls through the gas and condenses on the cold bottom plate. Some sort of ionizing radiation is needed. Methanol, isopropanol, or other alcohol vapor saturates the chamber; the alcohol falls as it cools down and the cold condenser provides a steep temperature gradient. The result is a supersaturated environment; as energetic charged particles pass through the gas they leave ionization trails. The alcohol vapor condenses around gaseous ion trails left behind by the ionizing particles; this occurs because alcohol and water molecules are polar, resulting in a net attractive force toward a nearby free charge. The result is a misty cloud-like formation, seen by the presence of droplets falling down to the condenser; when the tracks are emitted radially outward from a source, their point of origin can be determined.
Just above the cold condenser plate there is a volume of the chamber, sensitive to ionization tracks. The ion trail left by the radioactive particles provides an optimal trigger for condensation and cloud formation; this sensitive volume is increased in height by employing a steep temperature gradient, stable conditions. A strong electric field is used to draw cloud tracks down to the sensitive region of the chamber and increase the sensitivity of the chamber; the electric field can serve to prevent large amounts of background "rain" from obscuring the sensitive region of the chamber, caused by condensation forming above the sensitive volume of the chamber, thereby obscuring tracks by constant precipitation. A black background makes it easier to observe cloud tracks. A tangential light source is needed; this illuminates the white droplets against the black background. The tracks are not apparent until a shallow pool of alcohol is formed at the condenser plate. If a magnetic field is applied across the cloud chamber and negatively charged particles will curve in opposite directions, according to the Lorentz force law.
The bubble chamber was invented by Donald A. Glaser of the United States in 1952, for this, he was awarded the Nobel
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to high speeds and energies, to contain them in well-defined beams. Large accelerators are used for basic research in particle physics; the most powerful accelerator is the Large Hadron Collider near Geneva, built by the European collaboration CERN. It is a collider accelerator, which can accelerate two beams of protons to an energy of 6.5 TeV and cause them to collide head-on, creating center-of-mass energies of 13 TeV. Other powerful accelerators are KEKB at KEK in Japan, RHIC at Brookhaven National Laboratory, the Tevatron at Fermilab, Illinois. Accelerators are 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 manufacture of semiconductors, accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.
There are more than 30,000 accelerators in operation around the world. There are two basic classes of accelerators: electrodynamic accelerators. Electrostatic accelerators use static electric fields to accelerate particles; the most common types are the Cockcroft -- the Van de Graaff generator. A small-scale example of this class is the cathode ray tube in an ordinary old television set; the achievable kinetic energy for particles in these devices is determined by the accelerating voltage, limited by electrical breakdown. Electrodynamic or electromagnetic accelerators, on the other hand, use changing electromagnetic fields to accelerate particles. Since in these types the particles can pass through the same accelerating field multiple times, the output energy is not limited by the strength of the accelerating field; this class, first developed in the 1920s, is the basis for most modern large-scale accelerators. Rolf Widerøe, Gustav Ising, Leó Szilárd, Max Steenbeck, Ernest Lawrence are considered pioneers of this field and building the first operational linear particle accelerator, the betatron, the cyclotron.
Because colliders can give evidence of the structure of the subatomic world, accelerators were referred to as atom smashers in the 20th century. Despite the fact that most accelerators propel subatomic particles, the term persists in popular usage when referring to particle accelerators in general. Beams of high-energy particles are useful for fundamental and applied research in the sciences, in many technical and industrial fields unrelated to fundamental research, it has been estimated that there are 30,000 accelerators worldwide. Of these, only about 1% are research machines with energies above 1 GeV, while about 44% are for radiotherapy, 41% for ion implantation, 9% for industrial processing and research, 4% for biomedical and other low-energy research; the bar graph shows the breakdown of the number of industrial accelerators according to their applications. The numbers are based on 2012 statistics available from various sources, including production and sales data published in presentations or market surveys, data provided by a number of manufacturers.
For the most basic inquiries into the dynamics and structure of matter and time, physicists seek the simplest kinds of interactions at the highest possible energies. These entail particle energies of many GeV, the interactions of the simplest kinds of particles: leptons and quarks for the matter, or photons and gluons for the field quanta. Since isolated quarks are experimentally unavailable due to color confinement, the simplest available experiments involve the interactions of, leptons with each other, second, of leptons with nucleons, which are composed of quarks and gluons. To study the collisions of quarks with each other, scientists resort to collisions of nucleons, which at high energy may be usefully considered as 2-body interactions of the quarks and gluons of which they are composed, thus elementary particle physicists tend to use machines creating beams of electrons, positrons and antiprotons, interacting with each other or with the simplest nuclei at the highest possible energies hundreds of GeV or more.
The largest and highest energy particle accelerator used for elementary particle physics is the Large Hadron Collider at CERN, operating since 2009. Nuclear physicists and cosmologists may use beams of bare atomic nuclei, stripped of electrons, to investigate the structure and properties of the nuclei themselves, of condensed matter at high temperatures and densities, such as might have occurred in the first moments of the Big Bang; these investigations involve collisions of heavy nuclei – of atoms like iron or gold – at energies of several GeV per nucleon. The largest such particle accelerator is the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Particle accelerators can produce proton beams, which can produce proton-rich medical or research isotopes as opposed to the neutron-rich ones made in fission reactors. An example of this type of machine is LANSCE at Los Alamos. Besides being of fundamental interest, electrons accelerated in the magnetic field causes the high energy electrons to emit extre