Editing Ion source (section)

===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>