In experimental and applied particle physics, nuclear physics, 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 n ...

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

, or reactions in a particle accelerator. 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 detectors and semiconductor detectors are most typical) and

scintillation detector Scintillation can refer to: *Scintillation (astronomy), atmospheric effects which influence astronomical observations *Interplanetary scintillation, fluctuations of radio waves caused by the solar wind *Scintillation (physics), a flash of light pro ...

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 * 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 thinn ...

;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 **

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 ph ...

** Ionization chamber ** Proportional counter *

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 * Gaseous ionization detector ** Ionization chamber ** Proportional counter *** 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 w ...

** 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 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 characteristics ...

(RICH) **

and associated photomultiplier,

photodiode A photodiode is a light-sensitive semiconductor diode. It produces current when it absorbs photons. The package of a photodiode allows light (or infrared or ultraviolet radiation, or X-rays) to reach the sensitive part of the device. The packag ...

, or avalanche photodiode ***

Lucas cell A Lucas cell is a type of scintillation counter. It is used to acquire a gas sample, filter out the radioactive particulates through a special filter and then count the radioactive decay. The inside of the gas chamber is coated with ZnS( Ag) - a ...

***

Time-of-flight detector A time-of-flight (TOF) detector is a particle detector which can discriminate between a lighter and a heavier elementary particle of same momentum using their time of flight between two scintillators. The first of the scintillators activates a clo ...

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 betwe ...

* Calorimeter * Microchannel plate detector * Neutron detector

Modern detectors

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

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 photons or even visible light). 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 a northwestern suburb of Gene ...

**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 hundre ...

*** CMS *** ATLAS ***

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 **for the LEP *** Aleph

*** Delphi

*** L3 *** Opal

**for the

SPS SPS may refer to: Law and government * Agreement on the Application of Sanitary and Phytosanitary Measures of the WTO * NATO Science for Peace and Security * Single Payment Scheme, an EU agricultural subsidy * The Standard Procurement System, fo ...

*** The COMPASS Experiment *
Gargamelle
*
NA61/SHINE
*At Fermilab **for the Tevatron *
CDF
*
D0
** Mu2e *At

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 ...

**for

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 *** ZEUS *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 *
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

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 * XENON

On spacecraft

* Alpha Magnetic Spectrometer (AMS) * 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, 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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