Editing Ion source (section)

===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>