Beijing Electron–Positron Collider II
{{Short description|Chinese particle accelerator}}
The Beijing Electron–Positron Collider II (BEPC II) is a Chinese electron–positron collider, a type of particle accelerator, located in Shijingshan District, Beijing, People's Republic of China. It has been in operation since 2008 and has a circumference of 240.4 m.{{cite web
| url =http://www.ihep.ac.cn/english/E-Bepc/
| title =Beijing Electron Positron Collider (BEPC)
| date =2004-01-09
| publisher =Institute of High Energy Physics Chinese Academy of Sciences
| access-date =2015-10-15
| archive-url =https://web.archive.org/web/20160316234203/http://www.ihep.ac.cn/english/E-Bepc/
| archive-date =2016-03-16
| url-status =dead
}}
It was intended as a charm factory and continues the role of CLEO-c detector. The center of mass energy can go up to 4.6 GeV with a design luminosity of 1033 cm−2·s−1.{{Cite journal|title = Charm Factories: Present and Future|last = BESIII Collaboration|date = 17 Aug 2009|journal = AIP Conference Proceedings |volume=1182 |issue = 1|pages=406–409 |doi = 10.1063/1.3293832 |arxiv = 0908.2157 |bibcode = 2009AIPC.1182..406Z|s2cid = 118363265}} Operations began in summer 2008 and the machine has run at multiple energies.
History
File:BEPCmedallionFront 01.jpg
The construction of the original Beijing Electron Positron Collider was approved in 1983, as China was emerging from the Cultural Revolution, based on a proposal developed by Xie Jialin, who went on to oversee the construction of the machine. The construction of this collider was considered so important that then vice-premier Deng Xiaoping attended the groundbreaking in 1984 and returned in 1988 as the machine neared operation.Matin Durrani, Pushing the Boundaries, [https://physicsworld.com/a/pushing-the-boundaries/ Physics World], 15 Sep 2011.Min Zhang and Qian Pan, Jialin Xie wins China’s top science award, [https://newsline.linearcollider.org/2012/02/23/jialin-xie-wins-chinas-top-science-award/ International Linear Collider Newsline], 23 February 2012.Deng Xiaoping, China Must Take Its Place In the Field of High Technology, Oct. 24, 1988, [https://dengxiaopingworks.wordpress.com/2013/03/18/china-must-take-its-place-in-the-field-of-high-technology/ The Selected Works of Deng Xiaoping]
The original Beijing Electron Positron Collider was commissioned in 1989 and decommissioning began in 2000 as plans were developed for BEPC II, although operation continued until 2004. The shape of the BEPC has been described as a tennis racquet, with a linac with a beam energy of from 1.5 to 2.8 GeV serving as the handle, injecting counter-rotating beams of particles into a storage ring at the head, giving collision energies in the range from 3.0 to 5.6 GeV. The BEPC was built to investigate tau-charm physics, using the Beijing Spectrometer. Major accomplishments of the original BEPC included precision measurement of the Tau mass.[https://cerncourier.com/a/future-plans-take-shape-in-beijing/ Future Plans Take Place in Beijing], Cern Courier, 30 October 2000.{{cite journal | url=https://www.science.org/doi/abs/10.1126/science.262.5132.368 | doi=10.1126/science.262.5132.368 | title=The Present and Future of China's Particle Physics Research | year=1993 | last1=Zheng | first1=Zhipeng | journal=Science | volume=262 | issue=5132 | page=368 | pmid=17789941 | bibcode=1993Sci...262..368Z }}{{Cite book |url=https://doi.org/10.1007/978-3-030-34245-6_10 |doi=10.1007/978-3-030-34245-6_10 |chapter=The Largest Accelerators and Colliders of Their Time |title=Particle Physics Reference Library |year=2020 |last1=Hübner |first1=K. |last2=Ivanov |first2=S. |last3=Steerenberg |first3=R. |last4=Roser |first4=T. |last5=Seeman |first5=J. |last6=Oide |first6=K. |last7=Mess |first7=Karl Hubert |last8=Schmüser |first8=Peter |last9=Bailey |first9=R. |last10=Wenninger |first10=J. |pages=585–660 |isbn=978-3-030-34244-9 |s2cid=219874352 }} See Table 10.11, Historical listing of electron-electron and electron-positron colliders
BES III
{{main|BES III}}
The BES III (Beijing Spectrometer III) is the main detector{{Cite web |url=http://www.hep.umn.edu/bes3/ |title=Minnesota BES-III home page |access-date=2010-10-23 |archive-date=2010-09-01 |archive-url=https://web.archive.org/web/20100901213520/http://www.hep.umn.edu/bes3/ |url-status=dead }} for the upgraded BEPC II.
BES III uses a large superconducting solenoid to provide a 1-tesla magnetic field, and also features a helium gas-based tracking chamber and an electromagnetic calorimeter using 6240 caesium iodide crystals.
See also
References
{{reflist}}
{{coord missing|Beijing}}
External links
Record for [https://inspirehep.net/experiments/1239434 BEPC-BES II] experiment on INSPIRE-HEP
{{DEFAULTSORT:Beijing Electron-Positron Collider II}}
Category:2008 establishments in China
Category:Projects established in 2008
Category:Particle physics facilities
Category:Science and technology in the People's Republic of China