Editing Francium (section)

==Production==
[[File:franciumtrap.PNG|thumb|left|A [[magneto-optical trap]], which can hold neutral francium atoms for short periods of time.<ref name="sbtrapping" />|alt=A complex experimental setup featuring a horizontal glass tube placed between two copper coils.]]
Francium can be synthesized by a [[nuclear fusion|fusion]] reaction when a gold-197 target is bombarded with a beam of oxygen-18 atoms from a [[linear accelerator]] in a process originally developed at the physics department of the [[State University of New York at Stony Brook]] in 1995.<ref name="sbproduction">{{cite web| title = Production of Francium| work = Francium| publisher = [[State University of New York at Stony Brook]]| date = February 20, 2007| url = http://fr.physics.sunysb.edu/francium_news/production.HTM| access-date = March 26, 2007| url-status = dead| archive-url = https://archive.today/20071012010344/http://fr.physics.sunysb.edu/francium_news/production.HTM| archive-date = October 12, 2007}}</ref> Depending on the energy of the oxygen beam, the reaction can yield francium isotopes with masses of 209, 210, and 211.

:<sup>197</sup>Au + <sup>18</sup>O → <sup>209</sup>Fr + 6 n
:<sup>197</sup>Au + <sup>18</sup>O → <sup>210</sup>Fr + 5 n
:<sup>197</sup>Au + <sup>18</sup>O → <sup>211</sup>Fr + 4 n
{{multiple image
| align = right
| image1 = Francium (200,000 francium atoms in a magneto-optical trap).jpg
| width1 = {{#expr:150*150/165 round 0}}
| alt1 = A round ball of red light surrounded by a green glow
| caption1 = Image of light emitted by a sample of 200,000 francium atoms in a magneto-optical trap
| image2 = Fr,87.jpg
| width2 = 150
| alt2 = A small white spot in the middle surrounded by a red circle. There is a yellow ring outside the red circle, a green circle beyond the yellow ring and a blue circle surrounding all the other circles.
| caption2 = Heat image of 200,000 francium atoms in a magneto-optical trap, around 100 attograms
| footer = 
}}
The francium atoms leave the gold target as ions, which are neutralized by collision with [[yttrium]] and then isolated in a [[magneto-optical trap]] (MOT) in a gaseous unconsolidated state.<ref name="sbtrapping">{{cite web| title = Cooling and Trapping| work = Francium| publisher = [[State University of New York at Stony Brook]]| date = February 20, 2007| url = http://fr.physics.sunysb.edu/francium_news/trapping.HTM| access-date = May 1, 2007| url-status = dead| archive-url = https://archive.today/20071122170110/http://fr.physics.sunysb.edu/francium_news/trapping.HTM| archive-date = November 22, 2007}}</ref> Although the atoms only remain in the trap for about 30 seconds before escaping or undergoing nuclear decay, the process supplies a continual stream of fresh atoms. The result is a [[steady state]] containing a fairly constant number of atoms for a much longer time.<ref name="sbtrapping" /> The original apparatus could trap up to a few thousand atoms, while a later improved design could trap over 300,000 at a time.<ref name="chemnews">{{cite journal|url=http://pubs.acs.org/cen/80th/francium.html|title=Francium|journal=Chemical and Engineering News|date=2003|first=Luis A. |last=Orozco |volume=81|issue=36|pages=159|doi=10.1021/cen-v081n036.p159}}</ref> Sensitive measurements of the light emitted and absorbed by the trapped atoms provided the first experimental results on various transitions between atomic energy levels in francium. Initial measurements show very good agreement between experimental values and calculations based on quantum theory. The research project using this production method relocated to [[TRIUMF]] in 2012, where over 10<sup>6</sup> francium atoms have been held at a time, including large amounts of <sup>209</sup>Fr in addition to <sup>207</sup>Fr and <sup>221</sup>Fr.<ref>{{cite report |url= https://www.osti.gov/servlets/purl/1214938 |title= Project Closeout Report: Francium Trapping Facility at TRIUMF |publisher= U.S. Department of Energy |date= September 30, 2014 |doi= 10.2172/1214938 |last1= Orozco |first1= Luis A.}}</ref><ref>{{cite journal |journal= Journal of Instrumentation |title= Commissioning of the Francium Trapping Facility at TRIUMF |first1= M |last1= Tandecki |first2= J. |last2= Zhang |first3= R. |last3= Collister |first4= S. |last4= Aubin |first5= J. A. |last5= Behr |first6= E. |last6= Gomez |first7= G. |last7= Gwinner |first8= L. A. |last8= Orozco |first9= M. R. |last9= Pearson |s2cid= 15501597 |volume= 8 |issue= 12 |pages= 12006 |year= 2013 |doi= 10.1088/1748-0221/8/12/P12006 |arxiv= 1312.3562 |bibcode= 2013JInst...8P2006T}}</ref>

Other synthesis methods include bombarding radium with neutrons, and bombarding thorium with protons, [[deuterium|deuterons]], or [[helium]] [[ion]]s.<ref name="mcgraw">{{Cite book| contribution = Francium| date = 2002| title = McGraw-Hill Encyclopedia of Science & Technology| volume = 7| pages = [https://archive.org/details/mcgrawhillencycl165newy/page/493 493–494]| publisher = McGraw-Hill Professional| isbn = 978-0-07-913665-7| title-link = McGraw-Hill Encyclopedia of Science & Technology}}</ref>

<sup>223</sup>Fr can also be isolated from samples of its parent <sup>227</sup>Ac, the francium being milked via elution with NH<sub>4</sub>Cl–CrO<sub>3</sub> from an actinium-containing cation exchanger and purified by passing the solution through a [[silicon dioxide]] compound loaded with [[barium sulfate]].<ref>{{Ullmann | first1=Cornelius |last1=Keller |first2=Walter |last2=Wolf |first3=Jashovam |last3=Shani | title = Radionuclides, 2. Radioactive Elements and Artificial Radionuclides | doi = 10.1002/14356007.o22_o15}}</ref>

In 1996, the Stony Brook group trapped 3000 atoms in their MOT, which was enough for a video camera to capture the light given off by the atoms as they fluoresce.<ref name="chemnews" /> Francium has not been synthesized in amounts large enough to weigh.<ref name="andyscouse" /><ref name="nbb" /><ref name="losalamos">{{cite web | title = Francium |publisher = Los Alamos National Laboratory |year = 2011 |url = http://periodic.lanl.gov/87.shtml |access-date = February 19, 2012}}</ref>