Editing Vacuum tube (section)

=== Use of Radioactive Materials ===
[[File:Zellweger Glow Tube.jpg|thumb|Zellweger glow tube that contains Radium-226 or Tritium. There are no indicators to alert to the presence of radioactive materials]]
Certain vacuum tubes have utilized radioactive materials to enhance their performance. These radioative materials are used to ionize the fill gas within the tube. This ionization process ensures reliable and consistent operation by providing a steady current when a high voltage is applied, thereby improving the tube's performance and stability. The radioactive source speeds up the operation of the tube and ensures that the tube output is steady and not subject to random fluctuations by providing an instantaneous current when a high voltage is applied.<ref>{{Cite web |title=Electron Tubes |url=https://www.orau.org/health-physics-museum/collection/consumer/miscellaneous/electron-tubes.html |access-date=2025-02-12 |website=Museum of Radiation and Radioactivity |language=en}}</ref>

The various radioactive sources that have been used in these devices include:

* [[Tritium]] (H-3)
* [[Carbon-14]] (C-14)
* [[Cobalt-60]] (Co-60)
* [[Nickel-63]] (Ni-63)
* [[Krypton-85]] (Kr-85)
* [[Cesium-137]] (Cs-137)
* [[Isotopes of promethium|Promethium-147]] (Pm-147)
* [[Lead-210]] (Pb-210)
* [[Radium-226]] (Ra-226)
* [[Thorium-232]] (Th-232)

Examples include the Western Electric 346B tube, which contains radium-226, and the [[Zellweger off-peak|Zellweger ZE22/3]] glow tube, which may contain either radium-226 or tritium.