In experimental and applied

particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and ...

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the ...

, and

nuclear engineering Nuclear engineering is the branch of engineering concerned with the application of breaking down atomic nuclei (fission) or of combining atomic nuclei ( fusion), or with the application of other sub-atomic processes based on the principles of nu ...

, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing

particle In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, fro ...

s, such as those produced by nuclear decay,

cosmic radiation Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...

, or reactions in a

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to contain them in well-defined particle beam, beams. Large accelerators are used for fun ...

. Detectors can measure the particle energy and other attributes such as momentum, spin, charge, particle type, in addition to merely registering the presence of the particle.

Examples and types

Many of the detectors invented and used so far are ionization detectors (of which

gaseous ionization detector Gaseous ionization detectors are radiation detection instruments used in particle physics to detect the presence of ionizing particles, and in radiation protection applications to measure ionizing radiation. They use the ionising effect of radia ...

s and semiconductor detectors are most typical) and scintillation detectors; but other, completely different principles have also been applied, like Čerenkov light and transition radiation. Alpha radiation in a cloud chamber

Historical examples * Bubble chamber * Wilson cloud chamber (diffusion chamber) *

Photographic plate Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thi ...

;Detectors for radiation protection The following types of particle detector are widely used for radiation protection, and are commercially produced in large quantities for general use within the nuclear, medical, and environmental fields. * Dosimeter * Electroscope (when used as a portable dosimeter) *

Gaseous ionization detector Gaseous ionization detectors are radiation detection instruments used in particle physics to detect the presence of ionizing particles, and in radiation protection applications to measure ionizing radiation. They use the ionising effect of radia ...

Geiger counter A Geiger counter (also known as a Geiger–Müller counter) is an electronic instrument used for detecting and measuring ionizing radiation. It is widely used in applications such as radiation dosimetry, radiological protection, experimental ...

Ionization chamber The ionization chamber is the simplest type of gas-filled radiation detector, and is widely used for the detection and measurement of certain types of ionizing radiation, including X-rays, gamma rays, and beta particles. Conventionally, the ter ...

Proportional counter The proportional counter is a type of gaseous ionization detector device used to measure particles of ionizing radiation. The key feature is its ability to measure the energy of incident radiation, by producing a detector output pulse that is ''pro ...

Scintillation counter A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses. It consists of a scintillator w ...

* Semiconductor detector Commonly used detectors for particle and nuclear physics *

*** Multiwire proportional chamber *** Drift chamber *** Time projection chamber *** Micropattern gaseous detector **

Geiger–Müller tube The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation. It is named after Hans Geiger, who invented the principle in 1908, and Walther Müller, who collaborated ...

Spark chamber {{short description, Charged particle detector A spark chamber is a particle detector: a device used in particle physics for detecting electrically charged particles. They were most widely used as research tools from the 1930s to the 1960s and ha ...

*Solid-state detectors: ** Semiconductor detector and variants including CCDs ***Silicon Vertex Detector ** Solid-state nuclear track detector **

Cherenkov detector A Cherenkov detector (pronunciation: /tʃɛrɛnˈkɔv/; Russian: Черенко́в) is a particle detector using the speed threshold for light production, the speed-dependent light output or the speed-dependent light direction of Cherenkov radi ...

***

Ring-imaging Cherenkov detector The ring-imaging Cherenkov, or RICH, detector is a device for identifying the type of an electrically charged subatomic particle of known momentum, that traverses a transparent refractive medium, by measurement of the presence and characteristic ...

(RICH) **

and associated

photomultiplier A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for s ...

, photodiode, or

avalanche photodiode An avalanche photodiode (APD) is a highly sensitive semiconductor photodiode detector that exploits the photoelectric effect to convert light into electricity. From a functional standpoint, they can be regarded as the semiconductor analog of ...

*** Lucas cell *** Time-of-flight detector **

Transition radiation detector A transition radiation detector (TRD) is a particle detector using the \gamma-dependent threshold of transition radiation in a stratified material. It contains many layers of materials with different indices of refraction. At each interface betw ...

Calorimeter A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal micro calorimeters, titration calorimete ...

* Microchannel plate detector * Neutron detector

Modern detectors

Modern detectors in particle physics combine several of the above elements in layers much like an

onion An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the oni ...

Research particle detectors

Detectors designed for modern accelerators are huge, both in size and in cost. The term '' counter'' is often used instead of ''detector'' when the detector counts the particles but does not resolve its energy or ionization. Particle detectors can also usually track ionizing radiation (high energy

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are Massless particle, massless ...

s or even visible

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

). If their main purpose is radiation measurement, they are called ''radiation detectors'', but as photons are also (massless) particles, the term ''particle detector'' is still correct.

At colliders

*At CERN **for the

LHC The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundr ...

*** CMS ***

ATLAS An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geograp ...

***

ALICE Alice may refer to: * Alice (name), most often a feminine given name, but also used as a surname Literature * Alice (''Alice's Adventures in Wonderland''), a character in books by Lewis Carroll * ''Alice'' series, children's and teen books by ...

***

LHCb The LHCb (Large Hadron Collider beauty) experiment is one of eight particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parame ...

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Fermilab Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy United States Department of Energy National Labs, national laboratory specializing in high-energy parti ...

**for the

Tevatron The Tevatron was a circular particle accelerator (active until 2011) in the United States, at the Fermi National Accelerator Laboratory (also known as ''Fermilab''), east of Batavia, Illinois, and is the second highest energy particle collider ...

*
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DESY The Deutsches Elektronen-Synchrotron (English ''German Electron Synchrotron''), commonly referred to by the abbreviation DESY, is a national research center in Germany. It operates particle accelerators used to investigate the structure of matt ...

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HERA In ancient Greek religion, Hera (; grc-gre, Ἥρα, Hḗrā; grc, Ἥρη, Hḗrē, label=none in Ionic and Homeric Greek) is the goddess of marriage, women and family, and the protector of women during childbirth. In Greek mythology, she ...

*** H1 ***

HERA-B The HERA-B detector was a particle physics experiment at the HERA accelerator at the German national laboratory DESY that collected data from 1993 to 2003. It measured 8 m x 20 m x 9 m and weighed 1000 tons. The HERA-B collaboration consisted of s ...

***

HERMES Hermes (; grc-gre, Ἑρμῆς) is an Olympian deity in ancient Greek religion and mythology. Hermes is considered the herald of the gods. He is also considered the protector of human heralds, travellers, thieves, merchants, and orato ...

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ZEUS Zeus or , , ; grc, Δῐός, ''Diós'', label=genitive Boeotian Aeolic and Laconian grc-dor, Δεύς, Deús ; grc, Δέος, ''Déos'', label=genitive el, Δίας, ''Días'' () is the sky and thunder god in ancient Greek religion, ...

*At BNL **for the

RHIC The Relativistic Heavy Ion Collider (RHIC ) is the first and one of only two operating heavy-ion colliders, and the only spin-polarized proton collider ever built. Located at Brookhaven National Laboratory (BNL) in Upton, New York, and used by a ...

***

PHENIX Phenix or Phénix may refer to: Buildings * Phenix Baptist Church, West Warwick, Rhode Island, formerly on the National Register of Historic Places * Phenix Building (Chicago), an office building, demolished in 1957 * De Phenix, Marrum, a smock ...

*** Phobos *
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SLAC SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...

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Cornell Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to teac ...

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UC Irvine UC may refer to: Arts and entertainment * '' University Challenge'', a popular British quiz programme airing on BBC Two ** ''University Challenge (New Zealand)'', the New Zealand version of the British programme * Universal Century, one of the t ...

Under construction

*For

International Linear Collider The International Linear Collider (ILC) is a proposed linear particle accelerator. It is planned to have a collision energy of 500 GeV initially, with the possibility for a later upgrade to 1000 GeV (1 TeV). Although early proposed ...

(ILC) ** CALICE (Calorimeter for Linear Collider Experiment)

Without colliders

* Antarctic Muon And Neutrino Detector Array (AMANDA) * Cryogenic Dark Matter Search (CDMS) *

Super-Kamiokande Super-Kamiokande (abbreviation of Super-Kamioka Neutrino Detection Experiment, also abbreviated to Super-K or SK; ja, スーパーカミオカンデ) is a neutrino observatory located under Mount Ikeno near the city of Hida, Gifu Prefectur ...

XENON Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

On spacecraft

Alpha Magnetic Spectrometer The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment module that is mounted on the International Space Station (ISS).Kristine Rainey (April 2, 2013)Alpha Magnetic Spectrometer (AMS): How It Works NASA. Retrieved June 2, 20 ...

(AMS) *

JEDI Jedi (), Jedi Knights, or collectively the Jedi Order are the main heroic protagonists of many works of the '' Star Wars'' franchise. Working symbiotically alongside the Old Galactic Republic, and later supporting the Rebel Alliance, the Jedi ...

(Jupiter Energetic-particle Detector Instrument)

Theoretical Models of Particle Detectors

Beyond their experimental implementations, theoretical models of particle detectors are also of great importance to theoretical physics. These models consider localized non-relativistic quantum systems coupled to a quantum field. They receive the name of particle detectors because when the non-relativistic quantum system is measured in an excited state, one can claim to have detected a particle. The first instance of particle detector models in the literature dates from the 80's, where a particle in a box was introduced by

W. G. Unruh William George "Bill" Unruh (; born August 28, 1945) is a Canadians, Canadian physicist at the University of British Columbia, Vancouver who described the hypothetical Unruh effect in 1976. Early life and education Unruh was born into a Mennonit ...

in order to probe a quantum field around a black hole. Shortly after, Bryce DeWitt proposed a simplification of the model, giving rise to the Unruh-DeWitt detector model. Beyond their applications to theoretical physics, particle detector models are related to experimental fields such as

quantum optics Quantum optics is a branch of atomic, molecular, and optical physics dealing with how individual quanta of light, known as photons, interact with atoms and molecules. It includes the study of the particle-like properties of photons. Photons have ...

, where atoms can be used as detectors for the quantum electromagnetic field via the light-matter interaction. From a conceptual side, particle detectors also allow one to formally define the concept of particles without relying on asymptotic states, or representations of a quantum field theory. As M. Scully puts it, from an operational viewpoint one can state that "a particle is what a particle detector detects", which in essence defines a particle as the detection of excitations of a quantum field.

References

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