Difference between revisions 1229603 and 1284779 on enwikiversity

[[Image:Detectors summary 3.png|thumb|right|200px|This tree diagram shows the relationship between types and classification of most common particle detectors. Credit: [[commons:User:Wdcf|Wdcf]].]]
{{complete}}⏎
'''Radiation detectors''' provide a signal that is converted to an electric current. The device is designed so that the current provided is proportional to the characteristics of the incident radiation.
{{experimental}}
There are detectors that provide a change in substance as the signal and these may be automated to provide an electric current or quantified proportional to the amount of new substance.
{{primary}}
{{secondary}}
{{tertiary}}
{{research}}⏎
{{article}}
{{lecture}}
{{astronomy}}
{{Materials science}}
{{physics}}
{{technology}}

=Notation=

'''Notation''': let the symbol '''Def.''' indicate that a definition is following.

'''Notation''': symbols between [ and ] are replacement for that portion of a quoted text.

'''Notation''': let the symbol '''...''' indicate unneeded portion of a quoted text.

Sometimes these are combined as '''[...]''' to indicate that text has been replaced by '''...'''.

=Universals=

To help with definitions, their meanings and intents, there is the learning resource [[theory of definition]].

'''Def.''' a "characteristic or property that particular things have in common"<ref name=UniversalWikt>{{ cite web
|title=universal, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 28,
|year=2014
|url=https://en.wiktionary.org/wiki/universal
|accessdate=2014-06-04 }}</ref> is called a '''universal'''.

"When we examine common words, we find that, broadly speaking, proper names stand for particulars, while other substantives, adjectives, prepositions, and verbs stand for '''universals'''."<ref name=Russel>{{ cite book
|author=Bertrand Russel
|title=Chapter 9, In: ''The Problems of Philosophy''
|publisher=
|location=
|month=
|year=1912
|editor=
|pages=
|url=
|arxiv=
|bibcode=
|doi=
|pmid=
|isbn=
|accessdate=2014-06-04 }}</ref>

Such words as "entity", "object", "thing", and perhaps "body", words "connoting ''universal'' properties, ... constitute the very highest genus or "summum genus"" of a classification of universals.<ref name=Copi>{{ cite book
|author=Irving M. Copi
|title=Introduction to Logic
|publisher=The MacMillan Company
|location=New York
|month=
|year=1955
|editor=
|pages=472
|url=
|bibcode=
|doi=
|pmid=
|isbn=
|pdf=
|accessdate=2011-09-26 }}</ref> To propose a definition for say a plant whose flowers open at dawn on a warm day to be pollinated during the day time using the word "thing", "entity", "object", or "body" seems too general and is.

=Proof of concept=

'''Def.''' a “short and/or incomplete [[wikt:realization|realization]] of a certain [[wikt:method|method]] or idea to demonstrate its feasibility"<ref name=ProofofConceptWikt>{{ cite web
|title=proof of concept, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 10,
|year=2012
|url=http://en.wiktionary.org/wiki/proof_of_concept
|accessdate=2013-01-13 }}</ref> is called a '''proof of concept'''.

'''Def.''' evidence that demonstrates that a concept is possible is called '''proof of concept'''.

The proof-of-concept structure consists of
# background,
# procedures,
# findings, and
# interpretation.<ref name=Lehrman>{{ cite journal
|author=Ginger Lehrman and Ian B Hogue, Sarah Palmer, Cheryl Jennings, Celsa A Spina, Ann Wiegand, Alan L Landay, Robert W Coombs, Douglas D Richman, John W Mellors, John M Coffin, Ronald J Bosch, David M Margolis
|title=Depletion of latent HIV-1 infection in vivo: a proof-of-concept study
|journal=Lancet
|month=August 13,
|year=2005
|volume=366
|issue=9485
|pages=549-55
|url=http://www.sciencedirect.com/science/article/pii/S0140673605670985
|arxiv=
|bibcode=
|doi=10.1016/S0140-6736(05)67098-5
|pmid=
|pdf=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1894952/
|accessdate=2012-05-09 }}</ref>

Proof of concept for a radiation detector is that the radiation characteristics are accurately reported. This requires standards of performance and standard radiation sources.

=Control groups=
[[Image:Lewis rat.jpg|thumb|right|200px|This is an image of a Lewis rat. Credit: Charles River Laboratories.]]
The findings demonstrate a statistically systematic change from the status quo or the [[control group]].

“In the design of experiments, treatments [or special properties or characteristics] are applied to [or observed in] experimental units in the '''treatment group'''(s).<ref name=Hinkelmann>{{ cite book
|author=Klaus Hinkelmann, Oscar Kempthorne
|year=2008
|title=Design and Analysis of Experiments, Volume I: Introduction to Experimental Design
|url=http://books.google.com/?id=T3wWj2kVYZgC&printsec=frontcover
|edition=2nd
|publisher=Wiley
|isbn=978-0-471-72756-9
|mr=2363107 }}</ref> In ''comparative'' experiments, members of the complementary group, the '''control group''',  receive either ''no''&nbsp;treatment or a ''standard'' treatment.<ref name="Bailey">{{ cite book
|author=R. A. Bailey
|title=Design of comparative experiments
|publisher=Cambridge University Press
|url=http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521683579
|year=2008 
|mr=2422352
|isbn=978-0-521-68357-9
|url1=http://www.maths.qmul.ac.uk/~rab/DOEbook/ }}</ref>"<ref name=ControlGroup>{{ cite web
|title=Treatment and control groups, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 18,
|year=2012
|url=http://en.wikipedia.org/wiki/Control_group
|accessdate=2012-05-31 }}</ref>
{{clear}}⏎
⏎
=Astronomy=

A detector in [[radiation astronomy]] may need to be able to separate a collection of incoming radiation to obtain a clear set of signals for the radiation of interest. For example, a detector designed for [[red astronomy]] may need to be on the rocky-object surface of the [[Earth]] to separate X-rays and gamma-rays from red rays.

=Radiation=

(contracted; show full)

=Continuum=
[[Image:Continuous radiation source.jpg|thumb|right|200px|This is a xenon lamp which serves as a continuous light radiation source. Credit: Analytik Jena AG.]]
"A '''xenon arc lamp''' is a specialized type of gas discharge lamp, an electric light that produces light by passing electricity through ionized xenon gas at high pressure. It produces a bright white light that closely mimics natural sunlight."<ref name=XenonArcLamp>{{ cite 
journalweb
|title=Xenon arc lamp⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 6,
|year=2013
|url=http://en.wikipedia.org/wiki/Xenon_arc_lamp
|pdf=⏎
|accessdate=2013-05-22 }}</ref>

"[C]ontinuous spectra (as in bremsstrahlung and thermal radiation) are usually associated with free particles, such as atoms in a gas, electrons in an electron beam, or conduction band electrons in a metal. In particular, the position and momentum of a free particle have a continuous spectrum, but when the particle is confined to a limited space their spectra become discrete."<ref name=ContinuousSpectrum>{{ cite journalweb
|title=Continuous spectrum⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 31,
|year=2013
|url=http://en.wikipedia.org/wiki/Continuous_spectrum
|pdf=⏎
|accessdate=2013-05-22 }}</ref>

"Inverse Compton scattering is important in astrophysics. In X-ray astronomy, the accretion disc surrounding a black hole is presumed to produce a thermal spectrum. The lower energy photons produced from this spectrum are scattered to higher energies by relativistic electrons in the surrounding corona."<ref name=ComptonScattering>{{ cite journalweb
|title=Compton scattering⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 16,
|year=2013
|url=http://en.wikipedia.org/wiki/Compton_scattering
|pdf=⏎
|accessdate=2013-05-22 }}</ref>
{{clear}}

=Emissions=

"Condensed noble gases, most notably liquid xenon and liquid argon, are excellent radiation detection media. They can produce two signatures for each particle interaction: a fast flash of light (scintillation) and the local release of charge (ionisation). In two-phase xenon – so called since it involves liquid and gas phases in equilibrium – the scintillation light produced by an interaction in the liquid is detected directly with photomultiplier tubes; the ionisation electrons released at the interaction site are drifted up to the liquid surface under an external electric field, and subsequently emitted into a thin layer of xenon vapour. Once in the gas, they generate a second, larger pulse of light (electroluminescence or proportional scintillation), which is detected by the same array of photomultipliers. These systems are also known as xenon 'emission detectors'.<ref name="dolgoshein">B. A. Dolgoshein, V. N. Lebedenko & B. I. Rodionov, "New method of registration of ionizing-particle tracks in condensed matter", ''JETP Lett.'' 11(11): 351 (1970)</ref>"<ref name=ZEPLINIII>{{ cite journalweb
|title=ZEPLIN-III⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 10,
|year=2013
|url=http://en.wikipedia.org/wiki/ZEPLIN-III
|pdf=⏎
|accessdate=2013-05-22 }}</ref>

=Absorptions=
[[Image:Spectroscopy overview.svg|thumb|upright=2|center|300px|'''AThis is an overview of [[w:electromagnetic radiation|electromagnetic radiation]] absorption'''. This example discusses the general principle using [[w:Visible spectrum|visible light]] as a specific example. A white beam [[w:light source|source]] – emitting light of multiple wavelengths – is focused on a sample (the [[w:complementary color|complementary color]] pairs are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) are ''absorbed'' in order to excite the molecule. Other photons transmit unaffected and, if the radiation is in the visible region (400-700nm), the sample color is the complementary color of the absorbed light.  By comparing the [[w:attenuation|attenuation]] of the transmitted light with the incident, an absorption spectrum can be obtained. Credit: .]]
[[Image:Sodium in atmosphere of exoplanet HD 209458.jpg|thumb|upright=2|An example of applying Absorption spectroscopy is the first direct detection and chemical analysis of the atmosphere of a planet outside our solar system in 2001. Sodium filters the alien star  light of [[w:HD 209458|HD 209458]] as the hot Jupiter planet passes in front. The process and absorption spectrum are illustrated above. Credit: A. Feild, STScI and NASA website.]]
"'''Absorption spectroscopy''' refers to [[w:spectroscopy|spectroscopic]] techniques that measure the [[w:absorption (electromagnetic radiation)|absorption]] of [[w:electromagnetic radiation|radiation]], as a function of [[w:frequency|frequency]] or [[w:wavelength|wavelength]], due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the [[w:Absorption spectroscopy#Absorption spectrum|absorption spectrum]]. Absorption spectroscopy is performed across the [[w:electromagnetic spectrum|electromagnetic spectrum]]."<ref name=AbsorptionSpectroscopy>{{ cite journalweb
|title=Absorption apectroscopy⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 13,
|year=2013
|url=http://en.wikipedia.org/wiki/Absorption_spectroscopy
|pdf=⏎
|accessdate=2013-05-22 }}</ref>⏎
⏎
This example in the image at center discusses the general principle using [[w:Visible spectrum|visible light]] as a specific example. A white beam [[w:light source|source]] – emitting light of multiple wavelengths – is focused on a sample (the [[w:complementary color|complementary color]] pairs are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) are ''absorbed'' in order to excite the molecule. Other photons transmit unaffected and, if the radiation is in the visible region (400-700nm), the sample color is the complementary color of the absorbed light. By comparing the [[w:attenuation|attenuation]] of the transmitted light with the incident, an absorption spectrum can be obtained.
{{clear}}

=Bands=
[[Image:Bandgap in semiconductor.svg|right|thumb|200px|Semiconductor [[w:Electronic band structure|band structure]] is diagrammed qualitatively. Credit: [[commons:User:Pieter Kuiper|Pieter Kuiper]].]]
"[A] '''band gap''', also called an '''energy gap''' or '''bandgap''', is an energy range in a solid where no electron states can exist. In graphs of the [[w:electronic band structure|electronic band structure]] of solids, the band gap generally refers to the energy difference (in electron volts) between the top of the [[w:valence band|valence band]] and the bottom of the [[w:conduction band|conduction band]] in [[w:Electrical insulation|insulators]] and [[w:semiconductor|semiconductor]]s. This is equivalent to the energy required to free an [[w:Valence shell|outer shell]] [[w:Valence electron|electron]] from its orbit about the [[w:Atomic nucleus|nucleus]] to become a mobile [[w:charge carrier|charge carrier]], able to move freely within the solid material. So the band gap is a major factor determining the [[w:electrical conductivity|electrical conductivity]] of a solid. Substances with large band gaps are generally [[w:insulator (electrical)|insulators]], those with smaller band gaps are [[w:semiconductor|semiconductor]]s, while [[w:Electrical conductor|conductors]] either have very small band gaps or none, because the valence and conduction bands overlap."<ref name=BandGap>{{ cite journalweb
|title=Band gap⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 11,
|year=2013
|url=http://en.wikipedia.org/wiki/Band_gap
|pdf=⏎
|accessdate=2013-05-23 }}</ref>

"Every solid has its own characteristic energy band structure. This variation in band structure is responsible for the wide range of electrical characteristics observed in various materials. In semiconductors and insulators, electrons are confined to a number of bands of energy, and forbidden from other regions. The term "band gap" refers to the energy difference between the top of the valence band and the bottom of the conduction band. Electrons are able to jump from one band to another. However, in order for an electron to jump from a valence band to a conduction band, it requires a specific minimum amount of energy for the transition. The required energy differs with different materials. Electrons can gain enough energy to jump to the conduction band by absorbing either a phonon (heat) or a photon (light)."<ref name=BandGap/>

"[T]he '''electronic band structure''' (or simply '''band structure''') of a solid describes those ranges of energy, called ''energy bands'', that an electron within the solid may have ("allowed bands"), and ranges of energy called band gaps ("forbidden bands"), which it may not have."<ref name=ElectronicBandStructure>{{ cite journalweb
|title=Electronic band structure⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 20,
|year=2013
|url=http://en.wikipedia.org/wiki/Electronic_band_structure
|pdf=⏎
|accessdate=2013-05-23 }}</ref>

=Backgrounds=

"The main components of background noise in neutron detection are high-energy photons, which aren't easily eliminated by physical barriers."<ref name=NeutronDetection/>

"'''[N]oise''' is a random fluctuation in an electrical signal, a characteristic of all [[w:electronics|electronic]] [[w:electrical circuit|circuits]].<ref name=noise>{{ cite book
|author=C. D. Motchenbacher, J. A. Connelly
(contracted; show full)

"'''[S]pikes''' are fast, short duration electrical transients in voltage (voltage spikes), current (current spikes), or transferred energy (energy spikes) in an electrical circuit."<ref name=VoltageSpike>{{ cite 
journalweb
|title=Voltage spike⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 15,
|year=2013
|url=http://en.wikipedia.org/wiki/Voltage_spike
|pdf=⏎
|accessdate=2013-05-24 }}</ref>

"Fast, short duration electrical transients (overvoltages) in the electric potential of a circuit are typically caused by"<ref name=VoltageSpike/>

* Lightning strikes,
* Power outages,
* Tripped circuit breakers,
* Short circuits,
(contracted; show full)
“The basic set-up consists of 1600 water tanks ([[w:Cherenkov detector|water Cherenkov Detectors]], similar to the [[w:Haverah Park experiment|Haverah Park experiment]]) distributed over 3,000 square kilometres (1,200 sq mi), along with four atmospheric [[w:fluorescence|fluorescence]] detectors (similar to the [[w:High Resolution Fly's Eye Cosmic Ray Detector|High Resolution Fly's Eye]]) overseeing the surface array.”<ref name=PierreAugerObservatory>{{ cite 
journalweb
|title=Pierre Auger Observatory⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 10,
|year=2012
|url=http://en.wikipedia.org/wiki/Pierre_Auger_Observatory
|pdf=⏎
|accessdate=2012-06-19 }}</ref>

“The Pierre Auger Observatory is unique in that it is the first experiment that combines both ground and fluorescence detectors at the same site thus allowing cross-calibration and reduction of systematic effects that may be peculiar to each technique. The Cherenkov detectors use three large photomultiplier tubes to detect the [[w:Cherenkov radiation|Cherenkov radiation]] produced by high-energy particles passing through water in the tank. The time of arrival of high-e(contracted; show full)ing produced along the path of the charged particle. These tracks have distinctive shapes (for example, an alpha particle's track is broad and shows more evidence of deflection by collisions, while an electron's is thinner and straight). When any uniform magnetic field is applied across the cloud chamber, positively and negatively charged particles will curve in opposite directions, according to the Lorentz force law with two particles of opposite charge"<ref name=CloudChamber>{{ cite 
journalweb
|title=Cloud chamber⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 15,
|year=2013
|url=http://en.wikipedia.org/wiki/Cloud_chamber
|pdf=⏎
|accessdate=2013-05-17 }}</ref>

"The '''diffusion cloud chamber''' ... differs from the expansion cloud chamber in that it is continuously sensitized to radiation, and in that the bottom must be cooled to a rather low temperature, generally as cold as -15 degrees fahrenheit. Alcohol vapor is also often used due to its different phase transition temperatures. Dry-ice-cooled cloud chambers are a common demonstration and hobbyist device; the most common fluid used in t(contracted; show full)the kind of neutron detector used [such as] the [[w:Scintillation counter|scintillation detector]] and to the electronics used in the detection setup. Further, the hardware setup also defines key experimental parameters, such as source-detector distance, [[w:Solid angle|solid angle]] and detector shielding. Detection software consists of analysis tools that perform tasks such as graphical analysis to measure the number and energies of neutrons striking the detector.”<ref name=NeutronDetector>{{ cite 
journalweb
|title=Neutron detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 6,
|year=2012
|url=http://en.wikipedia.org/wiki/Neutron_detector
|pdf=⏎
|accessdate=2012-06-19 }}</ref>

“Neutrons react with a number of materials through elastic scattering producing a recoiling nucleus, [[w:Inelastic scattering|inelastic scattering]] producing an excited nucleus, or absorption with transmutation of the resulting nucleus. Most detection approaches rely on detecting the various reaction products.”<ref name=NeutronDetector/>

“[D]etection approaches for neutrons fall into several major categories<ref name=Tsoul>{{ cite book
(contracted; show full)
[[Image:Stopping H in Al.png|thumb|right|200px|The stopping power of aluminum for protons is plotted versus proton energy. Credit: H.Paul.]]
"Some of the alpha particles are absorbed by the atomic nuclei. The [alpha,proton] process produces protons of a defined energy which are detected. Sodium, magnesium, silicon, aluminium and sulfur can be detected by this method. This method was only used in the Mars Pathfinder APXS."<ref name=AlphaParticleXRaySpectrometer>{{ cite 
journalweb
|title=Alpha particle X-ray spectrometer⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 6.
|year=2013
|url=http://en.wikipedia.org/wiki/Alpha_particle_X-ray_spectrometer
|pdf=⏎
|accessdate=2013-05-17 }}</ref>

At right, the second figure shows the '''stopping power''' of aluminum metal single crystal for protons.

(contracted; show full)ctor (EPD) aboard the [[w:Galileo (spacecraft)|Galileo Orbiter]] is "designed to measure the numbers and energies of ... electrons whose energies exceed about 20 [[w:keV|keV]] ... The EPD [can] also measure the direction of travel of [electrons] ...  The EPD [uses] silicon solid state detectors and a [[w:time-of-flight|time-of-flight]] detector system to measure changes in the energetic [electron] population at Jupiter as a function of position and time."<ref name=GalileoSpacecraft>{{ cite 
journalweb
|title=Galileo (spacecraft)⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 7,
|year=2012
|url=http://en.wikipedia.org/wiki/Galileo_(spacecraft)
|pdf=⏎
|accessdate=2012-08-11 }}</ref>

"[The] two bi-directional, solid-state detector telescopes [are] mounted on a platform which [is] rotated by a stepper motor into one of eight positions. This rotation of the platform. combined with the spinning of the orbiter in a plane perpendicular to the platform rotation, [permits] a 4-pi [or 4π] steradian coverage of incoming [electrons]. The forward (0 degree) ends of the two telescopes [have] an unobstructed view over the [4π] sphere or [can] be positioned(contracted; show full)on|argon]] or [[w:germanium|germanium]], respectively, which are created by neutrinos interacting with the original substance. [[w:MINOS|MINOS]] uses a solid plastic [[w:scintillator|scintillator]] watched by phototubes, [[w:Borexino|Borexino]] uses a liquid [[w:pseudocumene|pseudocumene]] scintillator also watched by phototubes while the proposed [[w:NOνA|NOνA]] detector will use liquid scintillator watched by [[w:avalanche photodiode|avalanche photodiode]]s."<ref name=NeutrinoDetector>{{ cite 
journalweb
|title=Neutrino detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 23,
|year=2012
|url=http://en.wikipedia.org/wiki/Neutrino_detector
|pdf=⏎
|accessdate=2012-06-19 }}</ref>
{{clear}}

=Gamma-rays=
[[Image:HPGe detector90.jpg|thumb|center|250px|High-purity germanium detector (disconnected from liquid nitrogen dewar) is imaged. Credit: [[w:User:Sergio.ballestrero|Sergio.ballestrero]].]]
(contracted; show full)usion to make an n<sup>+</sup> ohmic contact, and boron implantation to make a p<sup>+</sup> contact. Coaxial detectors with a central n<sup>+</sup> contact are referred to as n-type detectors, while p-type detectors have a p<sup>+</sup> central contact. The thickness of these contacts represents a dead layer around the surface of the crystal within which energy depositions do not result in detector signals."<ref name=SemiconductorDetector>{{ cite 
journalweb
|title=Semiconductor detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 26,
|year=2013
|url=http://en.wikipedia.org/wiki/Semiconductor_detector
|pdf=⏎
|accessdate=2013-05-17 }}</ref>
{{clear}}

=X-rays=
[[Image:Proportional Counter Array RXTE.jpg|thumb|right|200px|This is an image of a real X-ray detector. The instrument is called the Proportional Counter Array and it is on the [[w:Rossi X-ray Timing Explorer|Rossi X-ray Timing Explorer]] (RXTE) satellite. Credit: NASA.]]
[[Image:Suzaku HXD.jpg|thumb|left|200px|The Suzaku Hard X-ray Detector is imaged before installation to the satellite. Credit: NASA.]]
Detectors such as the X-ray detector at right collect individual X-rays (photons of X-ray light), count them, discern the energy or wavelength, or how fast they are detected.

"'''X-ray detectors''' are devices used to measure the flux, spatial distribution, spectrum or other properties of X-rays. They vary in shape and function depending on their purpose. Some common principles used to detect X-rays include the ionization of gas, the conversion to visible light in a scintillator and the production of electron-hole pairs in a semiconductor detector."<ref name=XRayDetector>{{ cite journalweb
|title=X-ray detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 9,
|year=2013
|url=http://en.wikipedia.org/wiki/X-ray_detector
|pdf=⏎
|accessdate=2013-05-17 }}</ref>

"X-ray spectra can be measured either by energy dispersive or wavelength dispersive spectrometers."<ref name=XRayDetector/>

(contracted; show full)
|url=http://fuse.pha.jhu.edu/papers/technical/aas95/aas95.html
|title=The Far Ultraviolet Spectroscopic Explorer Mission
|work=JHU.edu
|author=D.J. Sahnow, et al.
|date=1995-07-03
|accessdate=2007-09-07 }}</ref>"<ref name=FarUltravioletSpectroscopicExplorer>{{ cite 
journalweb
|title=Far Ultraviolet Spectroscopic Explorer⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 9,
|year=2012
|url=http://en.wikipedia.org/wiki/Far_Ultraviolet_Spectroscopic_Explorer
|pdf=⏎
|accessdate=2012-06-26 }}</ref>

"Two mirror segments are coated with silicon carbide for reflectivity at the shortest ultraviolet wavelengths, and two mirror segments are coated with lithium fluoride over aluminum that reflects better at longer wavelengths." Each segment such as with silicon carbide has a dedicated microchannel plate. The other microchannel plates are for the lithium fluoride mirror system.

"LYRA will monitor the solar irradiance in four UV passbands. They have been chosen for their relevance to solar physics, aeronomy and Space Weather:"<ref name=LYRA>{{ cite journalweb
|title=LYRA⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 25,
|year=2013
|url=http://en.wikipedia.org/wiki/LYRA
|pdf=⏎
|accessdate=2013-05-24 }}</ref>

# the 115-125&nbsp;nm ''[[w:Lyman series|Lyman-α]] channel'',
# the 200-220&nbsp;nm ''[[w:Gerhard Herzberg|Herzberg]] continuum channel'',
# the ''Aluminium filter channel'' (17-50&nbsp;nm) including He II at 30.4&nbsp;nm, and
# the ''Zirconium filter channel'' (1-20&nbsp;nm).

"Diamond sensors make the instruments radiation-hard and solar-blind: their high bandgap energy makes them quasi-insensitive to visible light".<ref name=LYRA/>

Solar blind Cs-Te and Cs-I photocathode materials are sensitive to vacuum-UV and ultraviolet [and] [i]nsensitive to visible light and infrared (CsTe has cutoff at 320 nm, CsI at 200 nm)."<ref name=Photomultiplier>{{ cite journalweb
|title=Photomultiplier⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 14,
|year=2013
|url=http://en.wikipedia.org/wiki/Photomultiplier
|pdf=⏎
|accessdate=2013-05-24 }}</ref>

"Magnesium fluoride transmits ultraviolet down to 115 nm. [But, it is] [h]ygroscopic, though less than other alkali halides usable for UV windows."<ref name=Photomultiplier/>

=Opticals=

"'''Transition radiation''' (TR) is a form of [[w:electromagnetic radiation|electromagnetic radiation]] emitted when a [[w:charged particle|charged particle]] passes through [[w:Homogeneity and heterogeneity#Heterogeneity|inhomogeneous]] media, such as a boundary between two different media. This is in contrast to [[w:Cherenkov radiation|Cherenkov radiation]], which occurs when a charged particle passes through a [[w:Homogeneity and heterogeneity#Homogeneity|homogeneous]] [[w:dielectric|dielectric]] medium at a speed greater than the [[w:phase velocity|phase velocity]] of [[w:electromagnetic wave|electromagnetic wave]]s in that medium."<ref name=TransitionRadiation>{{ cite journalweb
|title=Transition radiation⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 28,
|year=2013
|url=http://en.wikipedia.org/wiki/Transition_radiation
|pdf=⏎
|accessdate=2013-05-20 }}</ref>

"'''Optical Transition radiation''' is produced by [[w:Theory of relativity|relativistic]] charged particles when they cross the interface of two media of different dielectric constants. The emitted radiation is the homogeneous difference between the two inhomogeneous solutions of [[w:Maxwell's equation|Maxwell's equation]]s of the electric and magnetic fields of the moving particle in each medium separately. In other words,(contracted; show full)n increases with the relativistic [[w:Lorentz factor|gamma factor]].  Thus particles with large <math>\gamma</math> give off many photons, and small <math>\gamma</math> give off few. For a given energy, this allows a discrimination between a lighter particle (which has a high <math>\gamma</math> and therefore radiates) and a heavier particle (which has a low <math>\gamma</math> and radiates much less)."<ref name=TransitionRadiationDetector>{{ cite 
journalweb
|title=Transition radiation detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 7,
|year=2013
|url=http://en.wikipedia.org/wiki/Transition_radiation_detector
|pdf=⏎
|accessdate=2013-05-20 }}</ref>

"Multialkali (Na-K-Sb-Cs) [photocathode materials have a] wide spectral response from ultraviolet to near-infrared [where] special cathode processing can extend range to 930 nm. [These are] [u]sed in broadband spectrophotometers."<ref name=Photomultiplier/>

"Borosilicate glass [window material] is commonly used for near-infrared to about 300 nm."<ref name=Photomultiplier/>

=Visuals=

(contracted; show full)

The F502N is centered at 501.85 nm with a band pass of 2.97 nm. The F547M is centered at 546.1 nm with a band pass of 43.8 nm.

The Wide Field Planetary Camera (PC-2) replaced PC-1 and carried the following filters on the same filter wheels: F467M, F502N, F547M, F555W, and the F569W.<ref name=Krist/> In December 1993 PC-1 was replaced with PC-2 and the HST was declared operational on January 13, 1994.<ref name=HubbleSpaceTelescope>{{ cite 
journalweb
|title=Hubble Space Telescope⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=January 21,
|year=2013
|url=http://en.wikipedia.org/wiki/Hubble_Space_Telescope
|pdf=⏎
|accessdate=2013-01-22 }}</ref>

Onboard the HST is the Faint Object Camera (FOC) which carries filters for green astronomy: F470M, F480LP, F501N, F502N, and the F550M.<ref name=Krist/>

"The '''Wide Field Camera 3''' (WFC3) is the [[w:Hubble Space Telescope|Hubble Space Telescope]]'s last and most technologically advanced instrument to take images in the visible spectrum. It was installed as a replacement for the [[w:Wide Field and Planetary Camera 2|Wide Field and Planetary Camera 2]] during the first spacewalk of Space Shuttle mission [[w:STS-125|STS-125]] on May 14, 2009."<ref name=WideFieldCamera3>{{ cite journalweb
|title=Wide Field Camera 3⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=January 15,
|year=2013
|url=http://en.wikipedia.org/wiki/Wide_Field_Camera_3
|pdf=⏎
|accessdate=2013-01-22 }}</ref>

=Yellows=

"[T]he #8 yellow filter is used to show [[w:Classical albedo features on Mars|Mars's maria]] and [[w:Atmosphere of Jupiter#Zones, belts and jets|Jupiter's belts]].<ref name="lumicon">{{ cite web
|url=http://www.lumicon.com/astronomy-accessories.php?cid=1&cn=Filters
|title=filters - popular and hot telescope filters
|publisher=Lumicon international
|date=
|accessdate=2010-11-22
|url= http://web.archive.org/web/20101125034023/http://lumicon.com/astronomy-accessories.php?cid=1&cn=Filters
| archivedate= 25 November 2010 
| deadurl= no}}</ref>"<ref name=AstronomicalFilter>{{ cite journalweb
|title=Astronomical filter⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=25 January
|year=2013
|url=http://en.wikipedia.org/wiki/Astronomical_filter
|pdf=
|accessdate=2013-01-25 }}</ref>

Initially the Hubble Space Telescope had the Wide Field/Planetary Camera (WF/PC-1) aboard where the F555W, F569W, F588N, and F606W cover the entire yellow portion of the electromagnetic spectrum.

The Hubble's Faint Object Camera (FOC) uses F550M and F600M which cover from either side.
(contracted; show full)ave to be cooled to cut [[w:thermal noise|thermal noise]]. The materials in these are [[w:semiconductors|semiconductors]] with narrow band gaps. Incident IR photons can cause electronic excitations. In [[w:photoconductive|photoconductive]] detectors, the [[w:resistivity|resistivity]] of the detector element is monitored. [[w:Photovoltaic|Photovoltaic]] detectors contain a [[w:p-n junction|p-n junction]] on which photoelectric current appears upon illumination."<ref name=InfraredDetector>{{ cite 
journalweb
|title=Infrared detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 8,
|year=2012
|url=http://en.wikipedia.org/wiki/Infrared_detector
|pdf=⏎
|accessdate=2012-06-19 }}</ref>

The Hubble PC-1 used the F785LP, F791W, F814W, F850LP, F875M, F889N, F1042M, and F1083N filters for [[infrared astronomy]]. The PC-2 used F785LP, F791W, F814W, F850LP, F953N, and F1042M.

=Submillimeters=

"Metal-mesh filters have many applications for use in the far infrared (FIR)<ref name=melo08>{{ cite journal
|doi = 10.1364/AO.47.006064
(contracted; show full)|journal = Applied Optics
|year = 2008
|volume = 47
|issue = 33
|pages = 6251–6256
|url = http://www.opticsinfobase.org/ao/abstract.cfm?uri=ao-47-33-6251
|pmid = 19023391
|bibcode = 2008ApOpt..47.6251P }}</ref>"<ref name=MetalMeshOpticalFilters>{{ cite 
journalweb
|title=Metal-mesh optical filters⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=February 20,
|year=2013
|url=http://en.wikipedia.org/wiki/Metal-mesh_optical_filters
|pdf=⏎
|accessdate=2013-05-25 }}</ref>

=Radios=
[[Image:Coherer.jpg|right|thumb|A metal filings coherer is imaged. Credit: [[w:User:JA.Davidson|JA.Davidson]].]]
"The '''coherer''' ... consists of a tube or capsule containing two [[w:electrode|electrode]]s spaced a small distance apart, with metal filings in the space between them. When a [[w:radio frequency|radio frequency]] signal is applied to the device, the initial high [[w:resistance (electricity)|resistance]] of the filings reduces, allowing an electric current to flow through it."<ref name=Coherer>{{ cite journalweb
|title=Coherer⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 22,
|year=2013
|url=http://en.wikipedia.org/wiki/Coherer
|pdf=⏎
|accessdate=2013-05-25 }}</ref>
{{clear}}

=Superluminals=
[[Image:Lhcbview.jpg|thumb|left|200px|LHCb detector is diagrammed. Credit: [[w:User:Oswald_le_fort|Oswald_le_fort]].]]
[[Image:Alpha Magnetic Spectrometer - 02.jpg|thumb|right|200px|AMS-02 is a RICH detector for analyzing cosmic rays. Credit: NASA.]]
(contracted; show full);math>N</math> is the number of ions observed in a time <math>t</math> (in seconds), <math>I</math> is the measured current (in [[w:amperes|amperes]]) and <math>e</math> is the [[w:elementary charge|elementary charge]] (about 1.60 × 10<sup>−19</sup> [[w:coulomb|C]]). Thus, a measured current of one nanoamp (10<sup>−9</sup> A) corresponds to about 6 billion ions striking the faraday cup each second."<ref name=FaradayCup>{{ cite 
journalweb
|title=Faraday cup⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 16,
|year=2013
|url=http://en.wikipedia.org/wiki/Faraday_cup
|pdf=⏎
|accessdate=2013-05-25 }}</ref>

=Gaseous objects=

"A '''gas detector''' is a device which detects the presence of various gases within an area"<ref name=GasDetector>{{ cite journalweb
|title=Gas detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 17,
|year=2013
|url=http://en.wikipedia.org/wiki/Gas_detector
|pdf=⏎
|accessdate=2013-05-26 }}</ref> or volume.

"The combination of [[w:nanotechnology|nanotechnology]] and [[w:microelectromechanical systems|microelectromechanical systems]] (MEMS) technology allows the production of a hydrogen microsensor that functions properly at room temperature. One type of MEMS-based hydrogen sensor is coated with a film consisting of nanostructured [[w:indium(III) oxide|indium oxide]] (In<sub>2</sub>O<sub>3</sub>) and [[w:tin oxide|tin oxide]] (SnO<(contracted; show full)
"A liquid is made up of tiny vibrating particles of matter, such as atoms and molecules, held together by intramolecular bonds. ... Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist."<ref name=Liquid>{{ cite 
journalweb
|title=Liquid⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 25,
|year=2013
|url=http://en.wikipedia.org/wiki/Liquid
|pdf=⏎
|accessdate=2013-05-26 }}</ref>

The first image at right shows liquid water using an infrared detector, but information confirming the presence of liquid water solely from the infrared image is inferred.

The image at left uses a visual radiation detector to record a meteor collision with liquid water.

"Reconstructions of seismic waves in the deep interior of the Earth show that there are no [[w:S-waves|S-waves]] in the [[w:outer core|outer core]]. This indicates that the outer core is liquid, because liquids cannot support shear. The outer core is liquid, and the motion of this highly conductive fluid generates the Earth's field (see [[w:geodynamo|geodynamo]])."<ref name=Geophysics>{{ cite journalweb
|title=Geophysics⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 18,
|year=2012
|url=http://en.wikipedia.org/wiki/Geophysics
|pdf=⏎
|accessdate=2012-11-16 }}</ref>
{{clear}}

=Rocky objects=
[[Image:Venus globe.jpg|thumb|left|200px|This is a false color image of Venus produced from a global [[w:Radar|radar]] view of the surface by the [[w:Magellan probe|Magellan probe]] while radar imaging between 1990-1994. Credit: NASA.]]
Often a rocky object is detected by the observation of impact craters usually using [[visual astronomy]] as part of [[crater astronomy]].

(contracted; show full)vided by a primary radiation source, an electron from an outer shell drops into its place. There are a limited number of ways in which this can happen ... The main transitions are given names: an L→K transition is traditionally called Kα, an M→K transition is called Kβ, an M→L transition is called Lα, and so on. Each of these transitions yields a fluorescent photon with a characteristic energy equal to the difference in energy of the initial and final orbital."<ref name=XRayFluorescence>{{ cite 
journalweb
|title=X-ray fluorescence⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=March 20,
|year=2013
|url=http://en.wikipedia.org/wiki/X-ray_fluorescence
|pdf=⏎
|accessdate=2013-05-12 }}</ref>
{{clear}}

=Compounds=

"[T]he detection of absorption by interstellar hydrogen fluoride (HF) [in the submillimeter band occurs] along the sight line to the submillimeter continuum sources W49N and W51."<ref name=Sonnentrucker>{{ cite journal
(contracted; show full)form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. If a piece of electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces a magnetic field of its own. If another coil is used to measure the magnetic field (acting as a magnetometer), the change in the magnetic field due to the metallic object can be detected."<ref name=MetalDetector>{{ cite 
journalweb
|title=Metal detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 13,
|year=2013
|url=http://en.wikipedia.org/wiki/Metal_detector
|pdf=⏎
|accessdate=2013-05-17 }}</ref>

"Modern top models are fully computerized, using integrated circuit technology to allow the user to set sensitivity, discrimination, track speed, threshold volume, notch filters, etc., and hold these parameters in memory for future use. Compared to just a decade ago, detectors are lighter, deeper-seeking, use less battery power, and discriminate better."<ref name=MetalDetector/>

(contracted; show full) energy particles have an estimated arrival rate of just 1 per km<sup>2</sup> per century, therefore the Auger Observatory has created a detection area the size of [[w:Rhode Island|Rhode Island]] — over 3,000 km<sup>2</sup> (1,200 sq mi) — in order to record a large number of these events. It is located in western [[w:Argentina|Argentina]]'s [[w:Mendoza Province|Mendoza Province]], in one of the South American [[w:Pampas|Pampas]].”<ref name=PierreAugerObservatory>{{ cite 
journalweb
|title=Pierre Auger Observatory⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 16,
|year=2013
|url=http://en.wikipedia.org/wiki/Pierre_Auger_Observatory
|pdf=⏎
|accessdate=2013-05-17 }}</ref>
{{clear}}

==Next to water==
[[Image:Old dome of the Big Bear Solar Observatory (Big Bear Lake, California).jpg|thumb|right|200px|The old dome on the main BBSO building is viewed from Big Bear Lake. Credit: [[w:User:Magi Media|Magi Media]].]]
"The '''Big Bear Solar Observatory''' (BBSO) is a [[w:solar observatory|solar observatory]] located on the north side of [[w:Big Bear Lake|Big Bear Lake]] in the [[w:San Bernardino Mountains|San Bernardino Mountains]] of southwestern [[w:San Bernardino County|San Bernardino County]], [[w:California|California]] (USA), approximately 120 kilometers (75 mi) east of downtown [[w:Los Angeles|Los Angeles]]."<ref name=BigBearSolarObservatory>{{ cite journalweb
|title=Big Bear Solar Observatory⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 31,
|year=2012
|url=http://en.wikipedia.org/wiki/Big_Bear_Solar_Observatory
|pdf=⏎
|accessdate=2012-11-06 }}</ref>

"The location at Big Bear Lake is optimal due to the clarity of the sky and the presence a body of water. The lake surface is about {{convert|2055|m|ft|sp=us}} above [[w:sea level|sea level]], putting it above a significant portion of the atmosphere. The main observatory building is in the open waters of the lake, and was originally reached by boat, though a causeway was added later.<ref name=BBSOCWAY>{{ cite web
|title=Big Bear Solar Observatory - Causeway
(contracted; show full)
 |author=R. Abbasi ''et al.'' (IceCube Collaboration)
 |year=2009
 |title=The IceCube Data Acquisition System: Signal Capture, Digitization, and Timestamping
 |journal=Nuclear Instruments and Methods A
 |volume=601 |pages=294–316
 |doi=10.1016/j.nima.2009.01.001
 |bibcode = 2009NIMPA.601..294T
 |arxiv=0810.4930 }}</ref>"<ref name=IceCubeNeutrinoObservatory>{{ cite 
journalweb
|title=IceCube Neutrino Observatory⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=August 10,
|year=2012
|url=http://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory
|pdf=⏎
|accessdate=2012-08-23 }}</ref>

==Under water==

"'''ANTARES''' is the name of a [[w:neutrino detector|neutrino detector]] residing 2.5&nbsp;km under the [[w:Mediterranean Sea|Mediterranean Sea]] off the coast of Toulon, France. It is designed to be used as a directional ''Neutrino Telescope'' to locate and observe neutrino flux from cosmic origins in the direction of the [[w:Southern Hemisphere|Southern Hemisphere]] of the [[Earth]], a complement to the southern hemisphere neutrino detector [[w:IceCube|IceCube]] that detects neutrinos from the North."<ref name=ANTARESTelescope>{{ cite journalweb
|title=ANTARES (telescope)⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=July 4,
|year=2012
|url=http://en.wikipedia.org/wiki/ANTARES_(telescope)
|pdf=⏎
|accessdate=2012-08-23 }}</ref>

=History=
[[Image:Oso5 wheel.gif|thumb|left|200px|The figure of the OSO 5 wheel contains detectors for gamma-rays, X-rays, ultraviolet, and visible (Zodiacal light). Credit: HEASARC, NASA.]]
[[Image:Oso5 NRLxrd.gif|thumb|right|The diagram of the Naval Research Laboratory Solar X-ray Radiation Ion Chamber Photometer shows the location of the center crystal. Credit: NASA.]]
(contracted; show full)
where ''n'' is the initial energy level, ''n&prime;'' is the final energy level, and ''R'' is the [[w:Rydberg constant|Rydberg constant]]. Meaningful values are returned only when ''n'' is greater than ''n&prime;'' and the limit of one over infinity is taken to be zero."<ref name=Hydrogenspectral>{{ cite 
journalweb
|title=Hydrogen spectral series⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 2,
|year=2012
|url=http://en.wikipedia.org/wiki/Hydrogen_spectral_series
|pdf=⏎
|accessdate=2012-05-14 }}</ref>

=Physics=
"A [[w:relativistic jet|relativistic jet]] coming out of the center of an [[w:active galactic nucleus|active galactic nucleus]] is moving along AB with a velocity v. We are observing the jet from the point O. At time <math>t_1</math> a light ray leaves the jet from point A and another ray leaves at time <math>t_2</math> from point B. Observer at O receives the rays at time <math>t_1^\prime</math> and <math>t_2^\prime</math> respectively."<ref name=SuperluminalMotion>{{ cite journalweb
|title=Superluminal motion⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 22,
|year=2013
|url=http://en.wikipedia.org/wiki/Superluminal_motion
|pdf=⏎
|accessdate=2013-05-26 }}</ref>

: <math>AB \ = \ v\delta t</math>
: <math>AC \ = \ v\delta t \cos\theta</math>
: <math>BC \ = \ v\delta t \sin \theta</math>
: <math>t_2-t_1 \ = \ \delta t</math>

: <math>t_1^\prime = t_1 + \frac{D_L+v\delta t \cos\theta}{c}</math>
(contracted; show full)rty of [[w:luminescence|luminescence]]<ref name=Leo>Leo, W. R. (1994). [http://books.google.com/books?id=8VufE4SD-AkC&printsec=frontcover “Techniques for Nuclear and particle Physics Experiments”], 2nd edition, Springer, ISBN 354057280</ref> when excited by [[w:ionizing radiation|ionizing radiation]]. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate, i.e., reemit the absorbed energy in the form of light."<ref name=Scintillator>{{ cite 
journalweb
|title=Scintillator⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 7,
|year=2012
|url=http://en.wikipedia.org/wiki/Scintillator
|pdf=⏎
|accessdate=2012-06-19 }}</ref> Here, "particle" refers to "ionizing radiation" and can refer either to charged [[w:Particle radiation|particulate radiation]], such as [[w:electrons|electrons]] and heavy charged particles, or to uncharged radiation, such as [[w:photons|photons]] and [[w:neutrons|neutrons]], provided that they have enough energy to induce ionization.

(contracted; show full)fying effect at each dynode stage. Each stage is at a higher potential than the previous to provide the accelerating field. The resultant output signal at the anode is in the form of a measurable pulse for each photon detected at the photocathode, and is passed to the processing electronics. The pulse carries information about the energy of the original incident radiation on the scintillator. Thus both intensity and energy of the radiation can be measured."<ref name=ScintillationCounter>{{ cite 
journalweb
|title=Scintillation counter⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 7,
|year=2013
|url=http://en.wikipedia.org/wiki/Scintillation_counter
|pdf=⏎
|accessdate=2013-05-17 }}</ref>

"The time evolution of the number of emitted scintillation photons ''N'' in a single scintillation event can often be described by the linear superposition of one or two exponential decays. For two decays, we have the form:<ref name=Leo/>

:<math>
N = A\exp\left(-\frac{t}{{\tau}_f}\right) + B\exp\left(-\frac{t}{{\tau}_s}\right)
</math>

(contracted; show full)ures are based on a single [[w:diode|diode]], they are called '''semiconductor diode detectors'''. When they contain many diodes with different functions, the more general term semiconductor detector is used. Semiconductor detectors have found broad application during recent decades, in particular for [[w:gamma ray|gamma]] and [[w:X-ray|X-ray]] [[w:spectrometry|spectrometry]] and as [[w:particle detector|particle detector]]s."<ref name=SemiconductorDetector>{{ cite 
journalweb
|title=Semiconductor detector⏎
|journal=, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=June 19,
|year=2012
|url=http://en.wikipedia.org/wiki/Semiconductor_detector
|pdf=⏎
|accessdate=2012-06-19 }}</ref>

"[[Radiation|[R]adiation]] is measured by means of the number of [[w:charge carrier|charge carrier]]s set free in the detector, which is arranged between two [[w:electrode|electrode]]s. Ionizing radiation produces free [[electron]]s and [[w:Electron hole|holes]]. The number of electron-hole pairs is proportional to the [[w:energy|energy]] transmitted by the radiation to the semiconductor.  As a result, a number of electrons are transferred from the [[w:valence ban(contracted; show full)onverted to a voltage and then a digital signal, which is interpreted by a computer to produce a digital image. Although silicon has outstanding electronic properties, it is not a particularly good absorber of X-ray photons. For this reason, X-rays first impinge upon scintillators made from such materials as gadolinium oxysulfide or caesium iodide. The scintillator absorbs the X-rays and converts them into visible light photons that then pass onto the photodiode array."<ref name=XRayDetector/>


=Research=

==Proof of concept==

'''Def.''' a “short and/or incomplete [[wikt:realization|realization]] of a certain [[wikt:method|method]] or idea to demonstrate its feasibility"<ref name=ProofofConceptWikt>{{ cite web
|title=proof of concept, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 10,
|year=2012
|url=http://en.wiktionary.org/wiki/proof_of_concept
|accessdate=2013-01-13 }}</ref> is called a '''proof of concept'''.

'''Def.''' evidence that demonstrates that a concept is possible is called '''proof of concept'''.

The proof-of-concept structure consists of
# background,
# procedures,
# findings, and
# interpretation.<ref name=Lehrman>{{ cite journal
|author=Ginger Lehrman and Ian B Hogue, Sarah Palmer, Cheryl Jennings, Celsa A Spina, Ann Wiegand, Alan L Landay, Robert W Coombs, Douglas D Richman, John W Mellors, John M Coffin, Ronald J Bosch, David M Margolis
|title=Depletion of latent HIV-1 infection in vivo: a proof-of-concept study
|journal=Lancet
|month=August 13,
|year=2005
|volume=366
|issue=9485
|pages=549-55
|url=http://www.sciencedirect.com/science/article/pii/S0140673605670985
|arxiv=
|bibcode=
|doi=10.1016/S0140-6736(05)67098-5
|pmid=
|pdf=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1894952/
|accessdate=2012-05-09 }}</ref>

Proof of concept for a radiation detector is that the radiation characteristics are accurately reported. This requires standards of performance and standard radiation sources.

==Control groups==
[[Image:Lewis rat.jpg|thumb|right|200px|This is an image of a Lewis rat. Credit: Charles River Laboratories.]]
The findings demonstrate a statistically systematic change from the status quo or the [[control group]].

“In the design of experiments, treatments [or special properties or characteristics] are applied to [or observed in] experimental units in the '''treatment group'''(s).<ref name=Hinkelmann>{{ cite book
|author=Klaus Hinkelmann, Oscar Kempthorne
|year=2008
|title=Design and Analysis of Experiments, Volume I: Introduction to Experimental Design
|url=http://books.google.com/?id=T3wWj2kVYZgC&printsec=frontcover
|edition=2nd
|publisher=Wiley
|isbn=978-0-471-72756-9
|mr=2363107 }}</ref> In ''comparative'' experiments, members of the complementary group, the '''control group''',  receive either ''no''&nbsp;treatment or a ''standard'' treatment.<ref name="Bailey">{{ cite book
|author=R. A. Bailey
|title=Design of comparative experiments
|publisher=Cambridge University Press
|url=http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521683579
|year=2008 
|mr=2422352
|isbn=978-0-521-68357-9
|url1=http://www.maths.qmul.ac.uk/~rab/DOEbook/ }}</ref>"<ref name=ControlGroup>{{ cite web
|title=Treatment and control groups, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=May 18,
|year=2012
|url=http://en.wikipedia.org/wiki/Control_group
|accessdate=2012-05-31 }}</ref>
{{clear}}⏎
⏎
=See also=
{{div col|colwidth=12em}}
* [[Principles of Radiation Astronomy]]
* [[Radiation]]
* [[Radiation astronomy]]
{{Div col end}}

=References=
(contracted; show full)* [http://www.springerlink.com/ SpringerLink]
* [http://www.tandfonline.com/ Taylor & Francis Online]
* [http://www.wikidoc.org/index.php/Main_Page WikiDoc The Living Textbook of Medicine]
* [http://onlinelibrary.wiley.com/advanced/search Wiley Online Library Advanced Search]
* [http://search.yahoo.com/web/advanced Yahoo Advanced Web Search]

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