Editing Getter (section)

==Types==
To avoid being contaminated by the atmosphere, the getter must be introduced into the vacuum system in an inactive form during assembly, and activated after evacuation. This is usually done by heat.<ref name="Espe">{{cite journal |last=Espe |first=Werner |author2=Max Knoll |author3=Marshall P. Wilder|title=Getter Materials for Electron Tubes |journal=Electronics |pages=80–86|publisher=McGraw-Hill |date=October 1950 |url=http://www.tubebooks.org/file_downloads/Getter_Material.pdf |issn=0883-4989 |access-date=21 October 2013}} on Pete Miller's [http://www.tubebooks.org/ Tubebooks] website</ref> Different types of getter use different ways of doing this:
; Flashed getter: The getter material is held inactive in a reservoir during assembly and initial evacuation, and then heated and evaporated, usually by [[induction heating]]. The vaporized getter, usually a volatile metal, instantly reacts with any residual gas, and then condenses on the cool walls of the tube in a thin coating, the ''getter spot'' or ''getter mirror'', which continues to absorb gas. This is the most common type, used in low-power [[vacuum tube]]s.
; Non-evaporable getter (NEG)<ref name="Jousten">{{cite book |last=Jousten |first=Karl |title=Handbook of Vacuum Technology |publisher=John Wiley & Sons |year=2008 |pages=463–474 |url=https://books.google.com/books?id=Gco_ytUu4QYC&pg=PA463 |isbn=978-3-527-40723-1}}</ref>: The getter remains in solid form.{{glossary
}}{{term
 | Coating getter}}{{defn
 | A coating applied to metal parts of the vacuum system that will be heated during use. Usually a nonvolatile metal powder sintered in a porous coating to the surface of the electrodes of power vacuum tubes, maintained at temperatures of 200 to 1200&nbsp;°C during operation.}}{{term
 | Bulk getter}}{{defn
 | Sheets, strips, wires, or sintered pellets of gas absorbing metals which are heated, either by mounting them on hot components or by a separate heating element. These can often be renewed or replaced.}}{{term
 | Getter pump or sorption pump}}{{defn
 | In laboratory vacuum systems, the bulk NEG getter is often held in a separate vessel with its own heater, attached to the vacuum system by a valve, so that it can be replaced or renewed when saturated.<ref name="Jousten" />{{glossary}}{{term
  | Ion getter pump}}{{defn
  | Uses a high voltage electrode to [[ionize]] the gas molecules and drive them into the getter surface. These can achieve very low pressures and are important in [[ultrahigh vacuum]] (UHV) systems.<ref name="Jousten" />
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