Editing Helium (section)

==== Scientific uses ====
The use of helium reduces the distorting effects of temperature variations in the space between [[lens (optics)|lenses]] in some [[telescope]]s due to its extremely low [[index of refraction]].<ref name="enc" /> This method is especially used in solar telescopes where a vacuum tight telescope tube would be too heavy.<ref>{{Cite journal|author = Jakobsson, H. |title = Simulations of the dynamics of the Large Earth-based Solar Telescope |journal = Astronomical & Astrophysical Transactions |volume = 13 |issue = 1 |pages = 35–46 |date= 1997 |doi = 10.1080/10556799708208113|bibcode = 1997A&AT...13...35J }}</ref><ref>{{Cite journal|bibcode = 1983ApOpt..22...10E|title = Tests of vacuum VS. helium in a solar telescope|author = Engvold, O.|author2 = Dunn, R.B.|author3 = Smartt, R. N.|author4 = Livingston, W. C.| journal = Applied Optics|date = 1983|pages = 10–12|issue = 1|volume = 22|pmid = 20401118|doi = 10.1364/AO.22.000010}}</ref>

Helium is a commonly used carrier gas for [[gas chromatography]].

The age of rocks and minerals that contain uranium and thorium can be estimated by measuring the level of helium with a process known as [[helium dating]].<ref name="nbb" /><ref name="enc" />

Helium at low temperatures is used in [[cryogenics]] and in certain cryogenic applications. As examples of applications, liquid helium is used to cool certain metals to the extremely low temperatures required for [[superconductivity]], such as in [[superconducting magnet]]s for [[magnetic resonance imaging]]. The [[Large Hadron Collider]] at [[CERN]] uses 96 [[metric ton]]s of liquid helium to maintain the temperature at {{convert|1.9|K|C F}}.<ref name="CERN-LHC">{{cite web|url=http://visits.web.cern.ch/visits/guides/tools/presentation/LHC_booklet-2.pdf |archive-url=https://web.archive.org/web/20110706223231/http://visits.web.cern.ch/visits/guides/tools/presentation/LHC_booklet-2.pdf |archive-date=2011-07-06 |title=LHC: Facts and Figures|publisher=[[CERN]]|access-date=2008-04-30}}</ref>