Editing Antimatter (section)

===Positrons===
{{Main|Positron}}

Positrons were reported<ref>
{{cite press release
 |publisher=[[Lawrence Livermore National Laboratory]]
 |date=3 November 2008
 |title=Billions of particles of anti-matter created in laboratory
 |url=https://phys.org/news/2008-11-billions-particles-anti-matter-laboratory.html
 |archive-url=https://web.archive.org/web/20151206012202/http://phys.org/news/2008-11-billions-particles-anti-matter-laboratory.html
 |url-status=dead
 |archive-date=6 December 2015
 |access-date=19 November 2008
}}</ref> in November 2008 to have been generated by [[Lawrence Livermore National Laboratory]] in large numbers. A [[laser]] drove [[electrons]] through a [[gold]] target's [[atomic nucleus|nuclei]], which caused the incoming electrons to emit [[energy]] [[quantum|quanta]] that decayed into both matter and antimatter. Positrons were detected at a higher rate and in greater density than ever previously detected in a laboratory. Previous experiments made smaller quantities of positrons using lasers and paper-thin targets; newer simulations showed that short bursts of ultra-intense lasers and millimeter-thick gold are a far more effective source.<ref>
{{cite magazine
 |date=19 November 2008
 |title=Laser creates billions of antimatter particles
 |url=http://www.cosmosmagazine.com/news/2345/laser-creates-billions-particles-antimatter
 |magazine=[[Cosmos Magazine]]
 |access-date=1 July 2009
 |archive-url=https://web.archive.org/web/20090522151227/http://www.cosmosmagazine.com/news/2345/laser-creates-billions-particles-antimatter
 |archive-date=22 May 2009
 |url-status=live
}}</ref>

In 2023, the production of the first electron-positron beam-plasma was reported by a collaboration led by researchers at [[University of Oxford]] working with the [[High-Radiation to Materials]] (HRMT)<ref>{{Cite journal |last1=Efthymiopoulos |first1=I |last2=Hessler |first2=C |last3=Gaillard |first3=H |last4=Grenier |first4=D |last5=Meddahi |first5=M |last6=Trilhe |first6=P |last7=Pardons |first7=A |last8=Theis |first8=C |last9=Charitonidis |first9=N |last10=Evrard |first10=S |last11=Vincke |first11=H |last12=Lazzaroni |first12=M |date=2011|journal = 2nd International Particle Accelerator Conference |title=HiRadMat: A New Irradiation Facility for Material Testing at CERN |url=https://cds.cern.ch/record/1403043}}</ref> facility at [[CERN]].<ref name=":0">{{Cite journal |last1=Arrowsmith |first1=C. D. |last2=Simon |first2=P. |last3=Bilbao |first3=P. J. |last4=Bott |first4=A. F. A. |last5=Burger |first5=S. |last6=Chen |first6=H. |last7=Cruz |first7=F. D. |last8=Davenne |first8=T. |last9=Efthymiopoulos |first9=I. |last10=Froula |first10=D. H. |last11=Goillot |first11=A. |last12=Gudmundsson |first12=J. T. |last13=Haberberger |first13=D. |last14=Halliday |first14=J. W. D. |last15=Hodge |first15=T. |date=2024-06-12 |title=Laboratory realization of relativistic pair-plasma beams |journal=Nature Communications |language=en |volume=15 |issue=1 |pages=5029 |doi=10.1038/s41467-024-49346-2 |pmid=38866733 |pmc=11169600 |issn=2041-1723|arxiv=2312.05244 |bibcode=2024NatCo..15.5029A }}</ref> The beam demonstrated the highest positron yield achieved so far in a laboratory setting. The experiment employed the 440 GeV proton beam, with <math>3\times 10^{11}</math> protons, from the [[Super Proton Synchrotron]], and irradiated a particle converter composed of [[carbon]] and [[tantalum]]. This yielded a total <math>1.5\times 10^{13}</math> electron-positron pairs via a [[particle shower]] process. The produced pair beams have a volume that fills multiple [[Debye length|Debye spheres]] and are thus able to sustain collective plasma oscillations.<ref name=":0" />