Editing Caesium (section)

===Other uses===
[[File:Electrostatic ion thruster-en.svg|thumb|upright=1.4|Schematics of an electrostatic ion thruster developed for use with caesium or mercury fuel|alt=Electrons beamed from an electron gun hit and ionize neutral fuel atoms; in a chamber surrounded by magnets, the positive ions are directed toward a negative grid that accelerates them. The force of the engine is created by expelling the ions from the rear at high velocity. On exiting, the positive ions are neutralized from another electron gun, ensuring that neither the ship nor the exhaust is electrically charged and are not attracted.]]
Caesium and mercury were used as a propellant in early [[ion thruster|ion engines]] designed for [[spacecraft propulsion]] on very long interplanetary or extraplanetary missions. The fuel was ionized by contact with a charged [[tungsten]] electrode. But corrosion by caesium on spacecraft components has pushed development in the direction of inert gas propellants, such as [[xenon]], which are easier to handle in ground-based tests and do less potential damage to the spacecraft.<ref name="USGS"/> Xenon was used in the experimental spacecraft [[Deep Space 1]] launched in 1998.<ref>{{cite journal |doi=10.1063/1.1150468 |title=NSTAR Xenon Ion Thruster on Deep Space 1: Ground and flight tests (invited) |date=2000 |last1=Marcucci |first1=M. G. |last2=Polk |first2=J. E. |journal=Review of Scientific Instruments |volume=71 |pages=1389–1400 |bibcode=2000RScI...71.1389M |issue=3}}</ref><ref>{{cite web |url=http://gltrs.grc.nasa.gov/reports/1999/TM-1999-209439.pdf |title=A Synopsis of Ion Propulsion Development Projects in the United States: SERT I to Deep Space I |first1=James S. |last1=Sovey |first2=Vincent K. |last2=Rawlin |first3=Michael J. |last3=Patterson |publisher=NASA |access-date=12 December 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090629225625/http://gltrs.grc.nasa.gov/reports/1999/TM-1999-209439.pdf |archive-date=29 June 2009}}</ref> Nevertheless, [[field-emission electric propulsion]] thrusters that accelerate liquid metal ions such as caesium have been built.<ref>{{cite conference |url=http://trs-new.jpl.nasa.gov/dspace/handle/2014/11649 |title=In-FEEP Thruster Ion Beam Neutralization with Thermionic and Field Emission Cathodes |format=PDF |access-date=25 January 2010 |conference=27th International Electric Propulsion Conference |place=Pasadena, California |date=October 2001 |pages=1–15 |author=Marrese, C. |author2=Polk, J. |author3=Mueller, J. |author4=Owens, A. |author5=Tajmar, M. |author6=Fink, R. |author7=Spindt, C. |name-list-style=amp |url-status=dead |archive-url=https://web.archive.org/web/20100527071653/http://trs-new.jpl.nasa.gov/dspace/handle/2014/11649 |archive-date=27 May 2010}}</ref>

[[Caesium nitrate]] is used as an [[oxidizing agent|oxidizer]] and [[pyrotechnic colorant]] to burn [[silicon]] in [[infrared]] [[flare (pyrotechnic)|flares]],<ref>{{cite web |url=http://www.freepatentsonline.com/6230628.html |work=United States Patent 6230628 |title=Infrared illumination compositions and articles containing the same |publisher=Freepatentsonline.com |access-date=25 January 2010 |archive-date=8 July 2021 |archive-url=https://web.archive.org/web/20210708104649/https://www.freepatentsonline.com/6230628.html |url-status=live }}</ref> such as the LUU-19 flare,<ref>{{cite web |url=https://fas.org/man/dod-101/sys/dumb/luu19.htm |title=LUU-19 Flare |publisher=Federation of American Scientists |date=23 April 2000 |access-date=12 December 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100806093502/http://www.fas.org/man/dod-101/sys/dumb/luu19.htm |archive-date=6 August 2010}}</ref> because it emits much of its light in the [[infrared|near infrared]] spectrum.<ref>{{cite journal |doi=10.1016/j.tca.2006.04.002 |title=Determination of the temperature and enthalpy of the solid–solid phase transition of caesium nitrate by differential scanning calorimetry |date=2006 |last1=Charrier |first1=E. |first2=E. L. |first3=P. G. |first4=H. M. |first5=B. |first6=T. T. |journal=Thermochimica Acta |volume=445 |pages=36–39 |last2=Charsley |last3=Laye |last4=Markham |last5=Berger |last6=Griffiths|issue=1 |bibcode=2006TcAc..445...36C }}</ref> Caesium compounds may have been used as fuel additives to reduce the [[radar cross-section|radar signature]] of [[exhaust gas|exhaust plumes]] in the [[Lockheed A-12]] [[CIA]] reconnaissance aircraft.<ref>{{cite book |isbn=978-1-84176-098-8 |page=47 |title=Lockheed SR-71: the secret missions exposed |last=Crickmore |first=Paul F. |publisher=Osprey |date=2000}}</ref> Caesium and rubidium have been added as a [[carbonate]] to glass because they reduce electrical conductivity and improve stability and durability of [[optical fiber|fibre optics]] and [[night vision]] devices. Caesium fluoride or caesium aluminium fluoride are used in fluxes formulated for brazing [[aluminium]] alloys that contain [[magnesium]].<ref name="USGS"/>

[[MHD generator|Magnetohydrodynamic (MHD) power]]-generating systems were researched, but failed to gain widespread acceptance.<ref>{{cite book |author=National Research Council (U.S.) |publisher=National Academy Press |date=2001 |title=Energy research at DOE—Was it worth it? |access-date=26 September 2010 |url=http://books.nap.edu/openbook.php?isbn=0309074487&page=52 |isbn=978-0-309-07448-3 |pages=190–194 |doi=10.17226/10165 |archive-date=23 March 2016 |archive-url=https://web.archive.org/web/20160323154247/http://www.nap.edu/read/10165/chapter/1 |url-status=live }}</ref> Caesium metal has also been considered as the working fluid in high-temperature [[Rankine cycle]] turboelectric generators.<ref>{{cite book |title=Economics of Caesium and Rubidium (Reports on Metals & Minerals) |publisher=Roskill Information Services |date=1984 |place=London, United Kingdom |author=Roskill Information Services |page=51 |isbn=978-0-86214-250-6}}</ref>

Caesium salts have been evaluated as antishock reagents following the administration of [[arsenic toxicity|arsenical drugs]]. Because of their effect on heart rhythms, however, they are less likely to be used than potassium or rubidium salts. They have also been used to treat [[epilepsy]].<ref name="USGS"/>

Caesium-133 can be [[laser cooling|laser cooled]] and used to probe fundamental and [[Quantum technology|technological]] problems in [[quantum mechanics|quantum physics]]. It has a particularly convenient [[Feshbach resonance|Feshbach]] spectrum to enable studies of [[ultracold atom]]s requiring tunable interactions.<ref>{{cite journal |last1=Chin |first1=Cheng |last2=Grimm |first2=Rudolf |last3=Julienne |first3=Paul |last4=Tiesinga |first4=Eite |date=29 April 2010 |title=Feshbach resonances in ultracold gases |journal=Reviews of Modern Physics |volume=82 |issue=2 |pages=1225–1286 |doi=10.1103/RevModPhys.82.1225 |arxiv=0812.1496 |bibcode=2010RvMP...82.1225C |s2cid=118340314}}</ref>