Particle physics experiments
Encyclopedia
Particle physics experiments briefly discusses a number of past, present, and proposed experiments with particle accelerators, throughout the world. In addition, some important accelerator interactions are discussed. Also, some notable systems components are discussed, named by project.
at CERN
. In addition, AEGIS is an acronym for: Antimatter Experiment: Gravity, Interferometry, Spectroscopy)
The proposed experiment:
It would attempt to determine if gravity affects antimatter
in the same way it affects matter
by testing its effect on an antihydrogen
beam. By sending a stream of antihydrogen through a series of diffraction grating
s, the pattern of light and dark patterns would allegedly enable the position of the beam to be pinpointed with up to 1% accuracy.
research project that took place at the AD Ring at CERN
. In 2005 ATHENA was disbanded and many of the former members became the ALPHA Collaboration. In August 2002, it was the first experiment to produce 50,000 low-energy antihydrogen atoms, as reported in the journal Nature
.
The experiment:
For antihydrogen
to be created, antiproton
s and positron
s must first be prepared. Once the antihydrogen is created, a high-resolution detector is needed to confirm that the antihydrogen was created, as well as to look at the spectrum of the antihydrogen in order to compare it to "normal" hydrogen.
The antiprotons are obtained from CERN's Antiproton Decelerator while the positrons are obtained from a positron accumulator. The antiparticles are then led into a recombination trap to create antihydrogen. The trap is surrounded by the ATHENA detector, which detects the annihilation of the antiprotons as well as the positrons.
Institutionalo collaboration:
The ATHENA Collaboration comprised the following institutions:
experiment that ran at the electron-positron collider ring DORIS II at DESY
. It is the first experiment that observed the mixing of the B meson
s (in 1987).
The ARGUS detector was a hermetic detector
with 90% coverage of the full solid angle. It had drift chambers, a time-of-flight system, an electromagnetic calorimeter
and a muon chamber system.
In physics
, the ARGUS distribution, named after this experiment, is the probability distribution
of the reconstructed invariant mass of a decayed particle candidate in continuum background. Its probability density function
(not normalized) is:
Sometimes a more general form is used to describe a more peaking-like distribution:
Here parameters c, χ, p represent the cutoff, curvature, and power (p = 0.5 gives a regular ARGUS) respectively.
developed out of TRAP, a collaboration whose members pioneered cold antiproton
s, cold positron
s, and first made the ingredients of cold antihydrogen
to interact. ATRAP members also pioneered accurate hydrogen
spectroscopy
and first observed hot antihydrogen atoms. The collaboration includes investigators from Harvard, the University of Bonn
, the Max Planck Institute for Quantum Optics, the University of Amsterdam, York University
, Seoul National University
, NIST, Forschungszentrum Jülich.
experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers investigating CP-violation effects at the High Energy Accelerator Research Organisation (KEK
) in Tsukuba, Ibaraki Prefecture
, Japan
.
at the University of Aarhus
, Århus, Denmark
. It is located in the lower levels of the University of Aarhus Department of Physics and Astronomy.
Its construction was announced on 18 September 1987. By 1998, it had been improved several times, notably increasing its maximum operation time to 30–35 hours. In December 2008, a contract was awarded to design and build ASTRID 2, which will be built adjacent to ASTRID.
ASTRID will be used to "top up" the new ring, allowing ASTRID 2 to operate nearly continuously.
at the University of Aarhus
, Århus, Denmark
.The contract to build the ring was awarded in December, 2008, and plans are expected to be complete by the end of 2009. It will be built in the lower levels of the University of Aarhus Department of Physics and Astronomy, adjacent to the existing ASTRID particle storage ring
. Rather than having an electron beam which decays over time, it will be continually "topped up" by a feed from ASTRID, allowing nearly constant current. It will generate synchrotron radiation
to provide a tunable beam of light, expected to be of "remarkable" quality, with wavelengths from the ultraviolet through x-rays.
at the CERN
laboratory in Geneva
. The decelerated antiproton
s are ejected to one of the connected experiments.
Current experiments
Former experiments:
experiments, an absorber is a block of material used to absorb
some of the energy of an incident particle
. Absorbers can be made of a variety of materials, depending on the purpose; lead
and liquid hydrogen
are common choices.
Most absorbers are used as part of a detector.
A more recent use for absorbers is for ionization cooling
, as in the International Muon Ionization Cooling Experiment
.
In solar power
, the most important part of the collector takes up the heat of the solar
radiation
through a medium (water + antifreeze
). This is heated and circulates between the collector and the storage tank. A high degree of efficiency is achieved by using black absorbers or, even better, through selective coating.
In sunscreen
, ingredients which absorb UVA/UVB rays, such as avobenzone
and octyl methoxycinnamate
, are known as absorbers. They are contrasted with physical "blockers" of UV radiation such as titanium dioxide
and zinc oxide
.
s.
The experiments conducted with particle accelerators are not regarded as part of accelerator physics. These belong (according to the objectives of the experiments) to particle physics
, nuclear physics
, condensed matter physics
, materials physics, etc. as well as to other sciences and technical fields. The types of experiments done at a particular accelerator and/or its other uses are largely constrained by the characteristics of the accelerator itself, such as energy (per particle), types of particles, beam intensity, beam quality, etc.
experiment, event
reconstruction is the process of interpreting the electronic
signals produced by the detector to determine the original particle
s that passed through, their momenta, directions, and the primary vertex of the event. Thus the initial physical process that occurred at the interaction point
of the particle accelerator
, whose study is the ultimate goal of the experiment, can be determined. The total event reconstruction is rarely possible (and rarely necessary); usually, only some part of the data described above is obtained and processed.
AEGIS (particle physics)
AEGIS is a proposed experiment to be set up at the Antiproton DeceleratorAntiproton Decelerator
The Antiproton Decelerator is a storage ring at the CERN laboratory in Geneva. It was built as a successor to the Low Energy Antiproton Ring and started operation in the year 2000...
at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
. In addition, AEGIS is an acronym for: Antimatter Experiment: Gravity, Interferometry, Spectroscopy)
The proposed experiment:
It would attempt to determine if gravity affects antimatter
Antimatter
In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...
in the same way it affects matter
Matter
Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume...
by testing its effect on an antihydrogen
Antihydrogen
Antihydrogen is the antimatter counterpart of hydrogen. Whereas the common hydrogen atom is composed of an electron and proton, the antihydrogen atom is made up of a positron and antiproton...
beam. By sending a stream of antihydrogen through a series of diffraction grating
Diffraction grating
In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as...
s, the pattern of light and dark patterns would allegedly enable the position of the beam to be pinpointed with up to 1% accuracy.
Athena
ATHENA was an antimatterAntimatter
In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...
research project that took place at the AD Ring at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
. In 2005 ATHENA was disbanded and many of the former members became the ALPHA Collaboration. In August 2002, it was the first experiment to produce 50,000 low-energy antihydrogen atoms, as reported in the journal Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
.
The experiment:
For antihydrogen
Antihydrogen
Antihydrogen is the antimatter counterpart of hydrogen. Whereas the common hydrogen atom is composed of an electron and proton, the antihydrogen atom is made up of a positron and antiproton...
to be created, antiproton
Antiproton
The antiproton 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....
s and positron
Positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1e, a spin of ½, and has the same mass as an electron...
s must first be prepared. Once the antihydrogen is created, a high-resolution detector is needed to confirm that the antihydrogen was created, as well as to look at the spectrum of the antihydrogen in order to compare it to "normal" hydrogen.
The antiprotons are obtained from CERN's Antiproton Decelerator while the positrons are obtained from a positron accumulator. The antiparticles are then led into a recombination trap to create antihydrogen. The trap is surrounded by the ATHENA detector, which detects the annihilation of the antiprotons as well as the positrons.
Institutionalo collaboration:
The ATHENA Collaboration comprised the following institutions:
- University of AarhusUniversity of AarhusAarhus University , located in the city of Aarhus, Denmark, is Denmark's second oldest and second largest university...
, DenmarkDenmarkDenmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark... - University of BresciaUniversity of BresciaThe University of Brescia is a college situated in Brescia, Italy. It was founded in 1982 and is branched in 4 Faculties.The first phase goes back to 1964, when the chamber of commerce of Brescia tried to create a biennial degree course of engineering; unfortunately the cost was too high...
, ItalyItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and... - CERNCERNThe European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
- University of GenoaUniversity of GenoaThe University of Genoa is one of the largest universities in Italy.Located in Liguria on the Italian Riviera, the university was founded in 1471. It currently has about 40,000 students, 1,800 teaching and research staff and about 1,580 administrative staff.- Campus :The University of Genoa is...
, Italy - University of PaviaUniversity of PaviaThe University of Pavia is a university located in Pavia, Lombardy, Italy. It was founded in 1361 and is organized in 9 Faculties.-History:...
, Italy - RIKENRIKENis a large natural sciences research institute in Japan. Founded in 1917, it now has approximately 3000 scientists on seven campuses across Japan, the main one in Wako, just outside Tokyo...
, Japan - Federal University of Rio de Janeiro, Brazil
- University of Wales Swansea, United KingdomUnited KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
- University of TokyoUniversity of Tokyo, abbreviated as , is a major research university located in Tokyo, Japan. The University has 10 faculties with a total of around 30,000 students, 2,100 of whom are foreign. Its five campuses are in Hongō, Komaba, Kashiwa, Shirokane and Nakano. It is considered to be the most prestigious university...
, JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south... - University of ZurichUniversity of ZurichThe University of Zurich , located in the city of Zurich, is the largest university in Switzerland, with over 25,000 students. It was founded in 1833 from the existing colleges of theology, law, medicine and a new faculty of philosophy....
, SwitzerlandSwitzerlandSwitzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition.... - National Institute for Nuclear Physics, Italy
ARGUS (experiment)
The ARGUS experiment was a particle physicsParticle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
experiment that ran at the electron-positron collider ring DORIS II at DESY
DESY
The DESY is the biggest German research center for particle physics, with sites in Hamburg and Zeuthen....
. It is the first experiment that observed the mixing of the B meson
B meson
B mesons are mesons composed of a bottom quark or bottom antiquark and either an up , down , strange or charm quark . The combination of a bottom antiquark and a top quark is not thought to be possible because of the top quark's short lifetime...
s (in 1987).
The ARGUS detector was a hermetic detector
Hermetic detector
In particle physics, a hermetic detector is a particle detector designed to observe all possible decay products of an interaction between subatomic particles in a collider by covering as large an area around the interaction point as possible and incorporating multiple types of sub-detectors...
with 90% coverage of the full solid angle. It had drift chambers, a time-of-flight system, an electromagnetic calorimeter
Calorimeter (particle physics)
In particle physics, a calorimeter is an experimental apparatus that measures the energy of particles. Most particles enter the calorimeter and initiate a particle shower and the particles' energy is deposited in the calorimeter, collected, and measured. The energy may be measured in its...
and a muon chamber system.
In physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, the ARGUS distribution, named after this experiment, is the probability distribution
Probability distribution
In probability theory, a probability mass, probability density, or probability distribution is a function that describes the probability of a random variable taking certain values....
of the reconstructed invariant mass of a decayed particle candidate in continuum background. Its probability density function
Probability density function
In probability theory, a probability density function , or density of a continuous random variable is a function that describes the relative likelihood for this random variable to occur at a given point. The probability for the random variable to fall within a particular region is given by the...
(not normalized) is:
Sometimes a more general form is used to describe a more peaking-like distribution:
Here parameters c, χ, p represent the cutoff, curvature, and power (p = 0.5 gives a regular ARGUS) respectively.
ATRAP
The ATRAP collaboration at CERNCERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
developed out of TRAP, a collaboration whose members pioneered cold antiproton
Antiproton
The antiproton 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....
s, cold positron
Positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1e, a spin of ½, and has the same mass as an electron...
s, and first made the ingredients of cold antihydrogen
Antihydrogen
Antihydrogen is the antimatter counterpart of hydrogen. Whereas the common hydrogen atom is composed of an electron and proton, the antihydrogen atom is made up of a positron and antiproton...
to interact. ATRAP members also pioneered accurate hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
and first observed hot antihydrogen atoms. The collaboration includes investigators from Harvard, the University of Bonn
University of Bonn
The University of Bonn is a public research university located in Bonn, Germany. Founded in its present form in 1818, as the linear successor of earlier academic institutions, the University of Bonn is today one of the leading universities in Germany. The University of Bonn offers a large number...
, the Max Planck Institute for Quantum Optics, the University of Amsterdam, York University
York University
York University is a public research university in Toronto, Ontario, Canada. It is Canada's third-largest university, Ontario's second-largest graduate school, and Canada's leading interdisciplinary university....
, Seoul National University
Seoul National University
Seoul National University , colloquially known in Korean as Seoul-dae , is a national research university in Seoul, Korea, ranked 24th in the world in publications in an analysis of data from the Science Citation Index, 7th in Asia and 42nd in the world by the 2011 QS World University Rankings...
, NIST, Forschungszentrum Jülich.
Belle experiment
The Belle experiment is a particle physicsParticle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers investigating CP-violation effects at the High Energy Accelerator Research Organisation (KEK
KEK
, known as KEK, is a national organization whose purpose is to operate the largest particle physics laboratory in Japan, which is situated in Tsukuba of Ibaraki prefecture. Established in 1997. The term "KEK" is also used to refer to the laboratory itself, which employs approximately 900 employees...
) in Tsukuba, Ibaraki Prefecture
Ibaraki Prefecture
is a prefecture of Japan, located in the Kantō region on the main island of Honshu. The capital is Mito.-History:Ibaraki Prefecture was previously known as Hitachi Province...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
ASTRID particle storage ring
ASTRID is a particle storage ringStorage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...
at the University of Aarhus
University of Aarhus
Aarhus University , located in the city of Aarhus, Denmark, is Denmark's second oldest and second largest university...
, Århus, Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
. It is located in the lower levels of the University of Aarhus Department of Physics and Astronomy.
Its construction was announced on 18 September 1987. By 1998, it had been improved several times, notably increasing its maximum operation time to 30–35 hours. In December 2008, a contract was awarded to design and build ASTRID 2, which will be built adjacent to ASTRID.
ASTRID will be used to "top up" the new ring, allowing ASTRID 2 to operate nearly continuously.
ASTRID 2 particle storage ring
ASTRID 2 will be a 46 meter particle storage ringStorage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...
at the University of Aarhus
University of Aarhus
Aarhus University , located in the city of Aarhus, Denmark, is Denmark's second oldest and second largest university...
, Århus, Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
.The contract to build the ring was awarded in December, 2008, and plans are expected to be complete by the end of 2009. It will be built in the lower levels of the University of Aarhus Department of Physics and Astronomy, adjacent to the existing ASTRID particle storage ring
ASTRID particle storage ring
ASTRID is a particle storage ring at Department of Physics and Astronomy Aarhus University, Aarhus, Denmark...
. Rather than having an electron beam which decays over time, it will be continually "topped up" by a feed from ASTRID, allowing nearly constant current. It will generate synchrotron radiation
Synchrotron radiation
The electromagnetic radiation emitted when charged particles are accelerated radially is called synchrotron radiation. It is produced in synchrotrons using bending magnets, undulators and/or wigglers...
to provide a tunable beam of light, expected to be of "remarkable" quality, with wavelengths from the ultraviolet through x-rays.
Anti-proton deccelerator
The Antiproton Decelerator (AD) is a storage ringStorage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...
at the CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
laboratory in Geneva
Geneva
Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...
. The decelerated antiproton
Antiproton
The antiproton 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....
s are ejected to one of the connected experiments.
Current experiments
| Expt. | Acronym | Full name |
|---|---|---|
| AD-2 | ATRAP | Anti-hydrogen Trap Collaboration |
| AD-3 | ASACUSA | Atomic Spectroscopy And Collisions Using Slow Anti-protons |
| AD-4 | ACE | Anti-proton Cell Experiment |
| AD-5 | ALPHA | Anti-hydrogen Laser Physics Apparatus |
| AD-6 | AEGIS | Anti-hydrogen Experiment: Gravity, Interferometry, Spectroscopy |
Former experiments:
| Expt. | Acronym | Full name |
|---|---|---|
| AD-1 | ATHENA Athena In Greek mythology, Athena, Athenê, or Athene , also referred to as Pallas Athena/Athene , is the goddess of wisdom, courage, inspiration, civilization, warfare, strength, strategy, the arts, crafts, justice, and skill. Minerva, Athena's Roman incarnation, embodies similar attributes. Athena is... |
ApparaTus for High-precision Experiments on Neutral Antimatter |
Absorber
In high energy physicsParticle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
experiments, an absorber is a block of material used to absorb
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
some of the energy of an incident particle
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
. Absorbers can be made of a variety of materials, depending on the purpose; lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
and liquid hydrogen
Liquid hydrogen
Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
are common choices.
Most absorbers are used as part of a detector.
A more recent use for absorbers is for ionization cooling
Ionization cooling
Ionization cooling is a process by which the beam emittance of a beam of particles may be reduced.In ionization cooling, particles are passed through some material. The momentum of the particles is reduced as they ionize atomic electrons in the material. Thus the normalised beam emittance is reduced...
, as in the International Muon Ionization Cooling Experiment
International Muon Ionization Cooling Experiment
The International Muon Ionization Cooling Experiment is a high energy physics experiment dedicated to observing ionization cooling of muons for the first time. This is a process where by the beam emittance of a beam is reduced in order to reduce the beam size, so that more muons can be accelerated...
.
In solar power
Solar power
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...
, the most important part of the collector takes up the heat of the solar
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
through a medium (water + antifreeze
Antifreeze
Antifreeze is a freeze preventive used in internal combustion engines and other heat transfer applications, such as HVAC chillers and solar water heaters....
). This is heated and circulates between the collector and the storage tank. A high degree of efficiency is achieved by using black absorbers or, even better, through selective coating.
In sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
, ingredients which absorb UVA/UVB rays, such as avobenzone
Avobenzone
Avobenzone is an oil soluble ingredient used in sunscreen products to absorb the full spectrum of UVA rays....
and octyl methoxycinnamate
Octyl methoxycinnamate
Octyl methoxycinnamate or octinoxate , trade names Eusolex 2292 and Uvinul MC80, is an organic compound that is an ingredient in some sunscreens and lip balms. It is an ester formed from methoxycinnamic acid and 2-ethylhexanol...
, are known as absorbers. They are contrasted with physical "blockers" of UV radiation such as titanium dioxide
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
and zinc oxide
Zinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...
.
Accelerator physics
Accelerator physics deals with the problems of building and operating particle acceleratorParticle accelerator
A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...
s.
The experiments conducted with particle accelerators are not regarded as part of accelerator physics. These belong (according to the objectives of the experiments) to particle physics
Particle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
, nuclear physics
Nuclear physics
Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those...
, condensed matter physics
Condensed matter physics
Condensed matter physics deals with the physical properties of condensed phases of matter. These properties appear when a number of atoms at the supramolecular and macromolecular scale interact strongly and adhere to each other or are otherwise highly concentrated in a system. The most familiar...
, materials physics, etc. as well as to other sciences and technical fields. The types of experiments done at a particular accelerator and/or its other uses are largely constrained by the characteristics of the accelerator itself, such as energy (per particle), types of particles, beam intensity, beam quality, etc.
Event reconstruction
In a particle detectorParticle detector
In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify high-energy particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a...
experiment, event
Event (particle physics)
An event in particle physics describes one set of particle interactions occurring in a brief span of time, typically recorded together. At modern particle accelerators this refers to the interactions that occur as a result of one beam crossing inside a detector....
reconstruction is the process of interpreting the electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
signals produced by the detector to determine the original particle
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
s that passed through, their momenta, directions, and the primary vertex of the event. Thus the initial physical process that occurred at the interaction point
Interaction point
In particle physics, an interaction point is the place where particles collide. One differentiates between the nominal IP, which is the design position of the IP, and the real or physics IP, which is the position where the particles actually collide...
of the particle accelerator
Particle accelerator
A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...
, whose study is the ultimate goal of the experiment, can be determined. The total event reconstruction is rarely possible (and rarely necessary); usually, only some part of the data described above is obtained and processed.
See also
- ALPHA Collaboration
- AntimatterAntimatterIn particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...
- CERNCERNThe European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
- List of synchrotron radiation facilities
- Gravitational interaction of antimatterGravitational interaction of antimatterThe gravitational interaction of antimatter with matter or antimatter has not been conclusively observed by physicists. While the overwhelming consensus among physicists is that antimatter will attract both matter and antimatter at the same rate that matter attracts matter, there is a strong...
- Particle physicsParticle physicsParticle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
External links
- ANTARES accelerator
- ANSTO home page
- National Medical Cyclotron
- Webpage of ARGUS Fest, a symposium to commemorate the 20th anniversary of the discovery of B-meson oscillations. (Last accessed on Sept. 10, 2007)
- ISA page for the ASTRID facility
- ISA page for the ASTRID 2 facility
- University of Aarhus Department of Physics and Astronomy
- The antimatter webpage of CERN for public
- A good figure about AD from http://athena-positrons.web.cern.ch/ATHENA-positrons/wwwathena/figpic.html
- The official web-site of the Antiproton Decelerator
- Official site
- CERN's public site
