Editing Ion source (section)

==Gas-discharge ion sources==
[[File:NASA NEXT Ion thruster.712983main NEXT LDT Thrusterhi-res full.jpg|thumb|300px|NASA's [[NEXT (ion thruster)]] space craft propulsion system]]
These ion sources use a [[plasma (physics)|plasma]] source or [[electric discharge]] to create ions.

===Inductively-coupled plasma===
{{Main|inductively coupled plasma}}
Ions can be created in an inductively coupled plasma, which is a plasma source in which the [[energy]] is supplied by [[electrical current]]s which are produced by [[electromagnetic induction]], that is, by time-varying [[magnetic field]]s.<ref>{{cite journal |last1=Broekaert |first1=J. A. C. |title=Inductively Coupled Plasmas in Analytical Atomic Spectrometry Eds.: A. Montaser and D. W. Golightly VCH, Weinheim, 2nd Edition. 1992, ISBN 3-527-28339-0, 984 pp., Hardcover, DM 296,— |journal=Acta Hydrochimica et Hydrobiologica |date=January 1993 |volume=21 |issue=6 |pages=327–328 |doi=10.1002/aheh.19930210610}}</ref>


===Microwave-induced plasma===
Microwave induced plasma ion sources are capable of exciting electrodeless gas discharges to create ions for trace element mass spectrometry.<ref name="Okamoto1994">{{cite journal|last1=Okamoto|first1=Yukio|title=High-sensitivity microwave-induced plasma mass spectrometry for trace element analysis|journal=Journal of Analytical Atomic Spectrometry|volume=9|issue=7|date=1994|page=745|issn=0267-9477|doi=10.1039/ja9940900745}}</ref><ref name="DouglasFrench1981">{{cite journal|last1=Douglas|first1=D. J.|last2=French|first2=J. B.|title=Elemental analysis with a microwave-induced plasma/quadrupole mass spectrometer system|journal=Analytical Chemistry|volume=53|issue=1|date=1981|pages=37–41|issn=0003-2700|doi=10.1021/ac00224a011}}</ref> A microwave plasma has high frequency [[electromagnetic radiation]] in the [[GHz]] range. It is capable of exciting electrodeless [[gas discharge]]s. If applied in [[surface-wave-sustained mode]], they are especially well suited to generate large-area plasmas of high plasma density. If they are both in surface-wave and [[resonator mode]], they can exhibit a high degree of spatial localization. This allows to spatially separate the location of plasma generations from the location of surface processing. Such a separation (together with an appropriate gas-flow scheme) may help reduce the negative effect, that particles released from a processed substrate may have on the [[plasma chemistry]] of the [[gas phase]].

===ECR ion source===
{{Main|electron cyclotron resonance#ECR ion sources}}
The ECR ion source makes use of the electron cyclotron resonance to ionize a plasma. Microwaves are injected into a volume at the frequency corresponding to the electron cyclotron resonance, defined by the magnetic field applied to a region inside the volume. The volume contains a low pressure gas.

===Glow discharge===
{{Main|glow discharge}}
[[File:Quarzkapillaritron.Betrieb.jpg|thumb|right|[[Capillaritron]] with quartz capillary in operation within a vacuum chamber: On the left the glowing capillary with the plasma up to the extraction cathode and on the right behind it the bluish glowing ion beam.]]
Ions can be created in an electric glow discharge. A glow discharge is a plasma formed by the passage of electric current through a low-pressure gas. It is created by applying a voltage between two metal [[electrode]]s in an evacuated chamber containing gas. When the voltage exceeds a certain value, called the [[striking voltage]], the gas forms a plasma.

A [[duoplasmatron]] is a type of glow discharge ion source that consists of a [[hot cathode]] or [[cold cathode]] that produces a plasma that is used to ionize a gas.<ref name="Wolf1995"/><ref name="Lejeune1974">{{cite journal|last1=Lejeune|first1=C.|title=Theoretical and experimental study of the duoplasmatron ion source|journal=Nuclear Instruments and Methods|volume=116|issue=3|date=1974|pages=417–428|issn=0029-554X|doi=10.1016/0029-554X(74)90821-0|bibcode=1974NucIM.116..417L}}</ref> THey can produce positive or negative ions.<ref name="Aberth1967">{{cite journal|last1=Aberth|first1=William|last2=Peterson|first2=James R.|title=Characteristics of a Low Energy Duoplasmatron Negative Ion Source|journal=Review of Scientific Instruments|volume=38|issue=6|date=1967|page=745|issn=0034-6748|doi=10.1063/1.1720882|bibcode=1967RScI...38..745A}}</ref> They are used for secondary ion mass spectrometry, ion beam etching, and high-energy physics.<ref name="CoathLong1995">{{cite journal|last1=Coath|first1=C. D.|last2=Long|first2=J. V. P.|title=A high-brightness duoplasmatron ion source for microprobe secondary-ion mass spectrometry|journal=Review of Scientific Instruments|volume=66|issue=2|date=1995|page=1018|issn=0034-6748|doi=10.1063/1.1146038|bibcode=1995RScI...66.1018C|doi-access=free}}</ref><ref name="Mahoney2013">{{cite book|author=Christine M. Mahoney|title=Cluster Secondary Ion Mass Spectrometry: Principles and Applications|url=https://books.google.com/books?id=hVSqwK0uqfsC&pg=PA65|date=9 April 2013|publisher=John Wiley & Sons|isbn=978-1-118-58925-0|pages=65–}}</ref><ref name="Humphries2013">{{cite book|author=Stanley Humphries|title=Charged Particle Beams|url=https://books.google.com/books?id=1GjCAgAAQBAJ&pg=PA309|date=25 July 2013|publisher=Dover Publications|isbn=978-0-486-31585-0|pages=309–}}</ref>

===Flowing afterglow===
{{Main|plasma afterglow}}
In a flowing plasma afterglow, ions are formed in a flow of inert gas, typically [[helium]] or [[argon]].<ref name="FergusonFehsenfeld1969">{{Cite book|last1=Ferguson|first1=E. E.|title=Chemical Reactions in Electrical Discharges|last2=Fehsenfeld|first2=F. C.|last3=Schmeltekopf|first3=A. L.|volume=80|date=1969|pages=83–91|issn=0065-2393|doi=10.1021/ba-1969-0080.ch006|chapter=Ion-Molecule Reaction Rates Measured in a Discharge Afterglow|series=Advances in Chemistry|isbn=978-0-8412-0081-4}}</ref><ref name="Ferguson1992">{{cite journal|last1=Ferguson|first1=Eldon E.|title=A Personal history of the early development of the flowing afterglow technique for ion-molecule reaction studies|journal=Journal of the American Society for Mass Spectrometry|volume=3|issue=5|date=1992|pages=479–486|issn=1044-0305|doi=10.1016/1044-0305(92)85024-E|pmid=24234490|url=https://zenodo.org/record/1258658|type=Submitted manuscript|doi-access=free|bibcode=1992JASMS...3..479F }}</ref><ref name="Bierbaum2014">{{cite journal|last1=Bierbaum|first1=Veronica M.|title=Go with the flow: Fifty years of innovation and ion chemistry using the flowing afterglow|journal=International Journal of Mass Spectrometry|date=2014|issn=1387-3806|doi=10.1016/j.ijms.2014.07.021|volume=377|pages=456–466|bibcode = 2015IJMSp.377..456B }}</ref> Reagents are added downstream to create ion products and study reaction rates. [[Flowing-afterglow mass spectrometry]] is used for trace gas analysis for organic compounds.<ref name="SmithŠpaněl2005">{{cite journal|last1=Smith|first1=David|last2=Španěl|first2=Patrik|title=Selected ion flow tube mass spectrometry (SIFT-MS) for on-line trace gas analysis|journal=Mass Spectrometry Reviews|volume=24|issue=5|date=2005|pages=661–700|issn=0277-7037|doi=10.1002/mas.20033|pmid=15495143|bibcode = 2005MSRv...24..661S }}</ref><ref>{{Cite journal|last1=Dhooghe|first1=Frederik|last2=Vansintjan|first2=Robbe|last3=Schoon|first3=Niels|last4=Amelynck|first4=Crist|date=2012-08-30|title=Studies in search of selective detection of isomeric biogenic hexen-1-ols and hexanal by flowing afterglow tandem mass spectrometry using [H3O]+ and [NO]+ reagent ions|journal=Rapid Communications in Mass Spectrometry|language=en|volume=26|issue=16|pages=1868–1874|doi=10.1002/rcm.6294|pmid=22777789|issn=1097-0231}}</ref>

===Spark ionization===
{{Main|spark ionization}}
Electric spark ionization is used to produce gas phase [[ion]]s from a solid sample. When incorporated with a mass spectrometer the complete instrument is referred to as a spark ionization mass spectrometer or as a spark source mass spectrometer (SSMS).<ref>{{cite journal |author1=H. E. Beske |author2=A. Hurrle |author3=K. P. Jochum | title = Part I. Principles of spark source mass spectrometry (SSMS) | date = 1981 | journal = [[Fresenius' Journal of Analytical Chemistry]] | volume = 309 | issue = 4 | pages = 258–261 | doi = 10.1007/BF00488596|s2cid=92433014 }}</ref>

A closed drift ion source uses a radial magnetic field in an annular cavity in order to confine electrons for ionizing a gas. They are used for [[ion implantation]] and for space propulsion ([[Hall-effect thruster]]s).