In experimental and applied

particle physics Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...

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 th ...

, and

nuclear engineering Nuclear engineering is the engineering discipline concerned with designing and applying systems that utilize the energy released by nuclear processes. The most prominent application of nuclear engineering is the generation of electricity. Worldwide ...

, 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 corpuscle 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, from s ...

s, such as those produced by nuclear decay,

cosmic radiation Cosmic rays or astroparticles 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 Sol ...

, 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 to contain them in well-defined particle beam, beams. Small accelerators are used for fundamental ...

. 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.

The operating of a nuclear radiation detector

The operating principle of a nuclear radiation detector can be summarized as follows: The detector identifies high-energy particles or photons—such as alpha, beta, gamma radiation, or neutrons—through their interactions with the atoms of the detector material. These interactions generate a primary signal, which may involve ionization of gas, the creation of electron-hole pairs in semiconductors, or the emission of light in scintillating materials. The primary signal is then amplified and processed by electronic systems. Finally, the resulting electrical pulse is analyzed to determine characteristics of the radiation, such as its energy, count rate, or spectral distribution.

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 detector A scintillator ( ) is a material that exhibits scintillation (physics), scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintill ...

s; 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 A bubble chamber is a vessel filled with a superheated transparent liquid (most often liquid hydrogen) used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded th ...

* Wilson cloud chamber (diffusion chamber) *

Photographic plate Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, d ...

(

Nuclear emulsion A nuclear emulsion plate is a type of particle detector first used in nuclear and particle physics experiments in the early decades of the 20th century. https://cds.cern.ch/record/1728791/files/vol6-issue5-p083-e.pdf''The Study of Elementary Partic ...

) ;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 A radiation dosimeter is a device that measures the equivalent dose, dose uptake of external ionizing radiation. It is worn by the person being monitored when used as a personal dosimeter, and is a record of the radiation dose received. Modern el ...

Electroscope The electroscope is an early scientific instrument used to detect the presence of electric charge on a body. It detects this by the movement of a test charge due to the Coulomb's law, Coulomb electrostatic force on it. The amount of charge on ...

(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 **

Ionization chamber The ionization chamber is the simplest type of gaseous ionisation detector, and is widely used for the detection and measurement of many types of ionizing radiation, including X-rays, gamma rays, alpha particles and beta particles. Conventionall ...

Proportional counter The proportional counter is a type of gaseous ionization detector device used to measure Charged particle, particles of ionizing radiation. The key feature is its ability to measure the Electronvolt, energy of incident radiation, by producing a det ...

Scintillation counter A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the Electron excitation, excitation effect of incident radiation on a Scintillation (physics), scintillating material, and detecting the resultant li ...

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

*** Multiwire proportional chamber ***

Drift chamber A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, by tracking the trails of gaseous ionization. was located via ...

***

Time projection chamber In physics, a time projection chamber (TPC) is a type of particle detector that uses a combination of electric fields and magnetic fields together with a sensitive volume of gas or liquid to perform a three-dimensional reconstruction of a particle ...

***

Micropattern gaseous detector Micropattern gaseous detectors (MPGDs) are a group of gaseous ionization detectors consisting of microelectronic structures with sub-millimeter distances between anode and cathode electrodes. When interacting with the gaseous medium of the detect ...

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 collaborate ...

** Spark chamber *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 type particle detector designed to detect and identify particles by the Cherenkov Radiation produced when a charged particle travels through the medium of th ...

*** Ring-imaging Cherenkov detector (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 sh ...

photodiode A photodiode is a semiconductor diode sensitive to photon radiation, such as visible light, infrared or ultraviolet radiation, X-rays and gamma rays. It produces an electrical current when it absorbs photons. This can be used for detection and me ...

, or avalanche photodiode *** Lucas cell *** Time-of-flight detector ** Transition radiation detector *

Calorimeter A calorimeter is a device 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 calorimeters ...

* 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'' , from Latin ), 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 onion which was classifie ...

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 particles that can ...

s or even visible

light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...

). 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 The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...

**for the LHC *** CMS ***

ATLAS An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets. Atlases have traditio ...

***

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 a particle physics detector collecting data at the Large Hadron Collider at CERN. LHCb specializes in the measurements of the parameters of CP violation in the interactions of b- and c-hadro ...

**for the LEP *** Aleph

*** Delphi

*** L3 *** Opal

**for the SPS *** The COMPASS Experiment *
Gargamelle
*
NA61/SHINE
*At

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

**for the

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

*
CDF
*
D0
** Mu2e *At

DESY DESY, short for Deutsches Elektronen-Synchrotron (English: ''German Electron Synchrotron''), is a national research centre for fundamental science located in Hamburg and Zeuthen near Berlin in Germany. It operates particle accelerators used to ...

**for

HERA In ancient Greek religion, Hera (; ; in Ionic Greek, Ionic and Homeric Greek) is the goddess of marriage, women, and family, and the protector of women during childbirth. In Greek mythology, she is queen of the twelve Olympians and Mount Oly ...

*** H1 *** HERA-B ***

HERMES Hermes (; ) is an Olympian deity in ancient Greek religion and mythology considered the herald of the gods. He is also widely considered the protector of human heralds, travelers, thieves, merchants, and orators. He is able to move quic ...

***

ZEUS Zeus (, ) is the chief deity of the List of Greek deities, Greek pantheon. He is a sky father, sky and thunder god in ancient Greek religion and Greek mythology, mythology, who rules as king of the gods on Mount Olympus. Zeus is the child ...

*At BNL **for the RHIC *** PHENIX *** Phobos *
STAR
*At SLAC **for th
PeP-II
*** BaBar **for th
SLC
*

*At Cornell **for CESR *** CLEO *** CUSB *At BINP **for th
VEPP-2M
an
VEPP-2000
*** ND *** SND ***CMD **for th
VEPP-4
*

*Others
MECO
from

UC Irvine UC may refer to: Education In the United States * University of California system * University of Charleston, West Virginia * University of Chicago, Illinois * University of Cincinnati, Ohio * Upsala College, East Orange, New Jersey (''defunct ...

Under construction

*For International Linear Collider (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; ) is a neutrino detector, neutrino observatory located Kamioka Observatory, under Mount Ikeno near the city of Hida, Gifu, Hida, ...

XENON Xenon is a chemical element; it has 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 (AMS) * DAMPE (DArk Matter Particle Explorer) * Fermi Gamma-ray Space Telescope *

JEDI Jedi (), Jedi Knights, or collectively the Jedi Order are fictional characters, and often protagonists, featured in many works within the '' Star Wars'' franchise. Working symbiotically alongside the Galactic Republic, the Jedi Order is depic ...

(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 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 and quantum chemistry that studies the behavior of photons (individual quanta of light). It includes the study of the particle-like properties of photons and their interaction ...

, 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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