Editing Argon (section)

===Scientific research===
Liquid argon is used as the target for neutrino experiments and direct [[dark matter]] searches. The interaction between the hypothetical [[Weakly interacting massive particles|WIMP]]s and an argon nucleus produces [[scintillation (physics)|scintillation]] light that is detected by [[photomultiplier tubes]]. Two-phase detectors containing argon gas are used to detect the ionized electrons produced during the WIMP–nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation light yield (about 51 photons/keV<ref>
{{cite journal
 |display-authors= 4
 |author= Gastler, Dan
 |author2= Kearns, Ed
 |author3= Hime, Andrew
 |author4= Stonehill, Laura C.
 |author5= Seibert, Stan
 |author6= Klein, Josh
 |author7= Lippincott, W. Hugh
 |author8= McKinsey, Daniel N.
 |author9= Nikkel, James A
 |s2cid= 6876533
 |date= 2012
 |title=Measurement of scintillation efficiency for nuclear recoils in liquid argon
 |doi= 10.1103/PhysRevC.85.065811
 |journal= Physical Review C
 |volume= 85
 |issue= 6
 |pages= 065811
 |arxiv=1004.0373
|bibcode = 2012PhRvC..85f5811G }}</ref>), is transparent to its own scintillation light, and is relatively easy to purify. Compared to [[xenon]], argon is cheaper and has a distinct scintillation time profile, which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic beta-ray background is larger due to {{chem|39|Ar}} contamination, unless one uses argon from underground sources, which has much less {{chem|39|Ar}} contamination. Most of the argon in Earth's atmosphere was produced by electron capture of long-lived {{chem|40|K}} ({{chem|40|K}} + e<sup>−</sup> → {{chem|40|Ar}} + ν) present in natural potassium within Earth. The {{chem|39|Ar}} activity in the atmosphere is maintained by cosmogenic production through the knockout reaction {{chem|40|Ar}}(n,2n){{chem|39|Ar}} and similar reactions. The half-life of {{chem|39|Ar}} is only 269&nbsp;years. As a result, the underground Ar, shielded by rock and water, has much less {{chem|39|Ar}} contamination.<ref>
{{Cite journal|author= Xu, J.
 |author2= Calaprice, F.
 |author3= Galbiati, C.
 |author4= Goretti, A.
 |author5= Guray, G.
 |s2cid= 117711599
 |name-list-style= amp
 |date= 26 April 2012
 |title=A Study of the Residual {{Chem|39|Ar}} Content in Argon from Underground Sources
 |journal= Astroparticle Physics
 |volume= 66
 |issue= 2015
 |pages= 53–60
 |arxiv=1204.6011 |display-authors=etal|doi= 10.1016/j.astropartphys.2015.01.002
 |bibcode= 2015APh....66...53X
 }}</ref> Dark-matter detectors currently operating with liquid argon include [[DarkSide (dark matter experiment)|DarkSide]], [[WIMP Argon Programme|WArP]], [[ArDM]], [[Cryogenic Low-Energy Astrophysics with Neon|microCLEAN]] and [[DEAP]]. Neutrino experiments include [[ICARUS (experiment)|ICARUS]] and [[MicroBooNE]], both of which use high-purity liquid argon in a [[time projection chamber]] for fine grained three-dimensional imaging of neutrino interactions.

At Linköping University, Sweden, the inert gas is being utilized in a vacuum chamber in which plasma is introduced to ionize metallic films.<ref>{{Cite web|title=Plasma electrons can be used to produce metallic films|url=https://phys.org/news/2020-05-plasma-electrons-metallic.html|date=May 7, 2020|website=Phys.org|access-date=May 8, 2020}}</ref> This process results in a film usable for manufacturing computer processors. The new process would eliminate the need for chemical baths and use of expensive, dangerous and rare materials.