Editing Diffusion pump (section)

==History==
In the late 19th century, most vacuums were created using a [[Sprengel pump]], which had the advantage of being very simple to operate, and capable of achieving quite good vacuum given enough time. Compared to later pumps, however, the pumping speed was very slow and the [[vapor pressure]] of the liquid mercury limited the ultimate vacuum.

Following his invention of the [[Holweck pump|molecular pump]], [[Wolfgang Gaede]] invented the diffusion pump in 1915,<ref>{{cite journal | year = 1915 | journal = [[Annalen der Physik]] | volume = 46 | page = 357 | author = Gaede, W. | doi = 10.1002/andp.19153510304 | title = Die Diffusion der Gase durch Quecksilberdampf bei niederen Drucken und die Diffusionsluftpumpe | issue = 3|bibcode = 1915AnP...351..357G | url = https://zenodo.org/record/1447291 }}</ref> and originally used [[Mercury (element)|elemental mercury]] as the working fluid. After its invention, the design was quickly commercialized by [[Leybold GmbH|Leybold]].<ref>{{cite web | last=Sella | first=Andrea | title=Classic Kit: Gaede's diffusion pump | website=Chemistry World | date=2009-04-28 | url=https://www.chemistryworld.com/opinion/classic-kit-gaedes-diffusion-pump/3004912.article | access-date=2019-08-03}}</ref> It was then improved by [[Irving Langmuir]]<ref>{{cite journal|title=The Condensation Pump: An Improved Form of High Vacuum Pump|first=Irving|last=Langmuir|journal=General Electric Review|year=1916|volume=19|pages=1060–1071|url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015075043383&view=1up&seq=1104}}</ref> and W. Crawford. [[Cecil Reginald Burch]] discovered the possibility of using [[silicone oil]] in 1928.<ref>{{cite journal | author = C. R. Burch | title = Oils, greases and high vacua | journal = [[Nature (journal)|Nature]] | volume = 122 | year = 1928 | page = 729 | doi = 10.1038/122729c0 | issue = 3080|bibcode = 1928Natur.122..729B | s2cid = 4126707 | doi-access = free }}</ref>