Editing Rubidium standard

{{Short description|Frequency standard}}
{{More footnotes|date=December 2022}}
[[File:Rb oscillator.jpg|thumb|right|Rb oscillator]]
[[File:Rubidium-oscillator.jpg|thumb|right|Schematic of a Rubidium Oscillator]]
A '''rubidium standard''' or '''rubidium atomic clock''' is a [[frequency standard]] in which a specified [[Hyperfine_structure#Use_in_defining_the_SI_second_and_meter|hyperfine transition]] of [[electron]]s in [[rubidium]]-87 atoms is used to control the output frequency.<ref name="wjrhist">{{cite journal |last1=Riley |first1=William J. Jr |title=A History of the Rubidium Frequency Standard |journal=IEEE Uffc-S |date=December 2019 |url=https://www.wriley.com/A%20History%20of%20the%20Rubidium%20Frequency%20Standard.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.wriley.com/A%20History%20of%20the%20Rubidium%20Frequency%20Standard.pdf |archive-date=2022-10-09 |url-status=live}}</ref>

==Synopsis==
The Rb standard is the most inexpensive, compact, and widely produced [[atomic clock]], used to control the frequency of [[television station]]s, [[cellular base station|cell phone base stations]], in test equipment, and [[global navigation satellite system]]s like [[Global Positioning System|GPS]]. Commercial rubidium clocks are less accurate than [[Caesium standard|caesium atomic clock]]s, which serve as [[Primary standard|primary frequency standards]], so a rubidium clock is usually used as a [[secondary frequency standard]]. 

Commercial rubidium frequency standards operate by disciplining a [[crystal oscillator]] to the rubidium hyperfine transition of 6.8 GHz ({{val|6834682610.904|u=Hz}}). The intensity of light from a rubidium [[discharge lamp]] that reaches a [[photodetector]] through a resonance cell will drop by about 0.1% when the rubidium vapor in the resonance cell is exposed to [[microwave]] power near the [[Hyperfine structure|transition frequency]]. The crystal oscillator is stabilized to the rubidium transition by detecting the light dip while sweeping an [[Radio frequency|RF]] [[frequency synthesizer|synthesizer]] (referenced to the crystal) through the transition frequency.

==See also==
* [[Hydrogen maser]]

== References ==
{{reflist}}

===Bibliography===
* [https://www.thinksrs.com/downloads/pdfs/catalog/PRS10c.pdf Stanford Research Systems documentation on the PRS10 frequency standard]
* {{NIST-PD|article=Time and Frequency from A to Z|url=https://www.nist.gov/pml/time-and-frequency-division/popular-links/time-frequency-z/time-and-frequency-z-re-ru|accessdate=January 14, 2024}}
* {{FS1037C}}


[[Category:Electronics standards]]
[[Category:Atomic clocks]]
[[Category:Rubidium]]