Beijing Electron–Positron Collider II

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The Beijing Electron–Positron Collider II (BEPC II) is a Chinese electron–positron collider, a type of particle accelerator, located in Beijing, People's Republic of China. It has been in operation since 2008 and has a circumference of 240m.[citation needed]

It was intended as a charm factory and continues the role CLEO-c detector. The center of mass energy can go up to 4.6 GeV with a design luminosity of 1033 cm−2s-1.[1] Operations began in summer 2008 and has run at multiple energies.

BES III[edit]

The BES III (Beijing Spectrometer III) is the main detector[2] for the upgraded BEPC II.

BES III uses a large superconducting solenoid (the most powerful magnet in China[citation needed]) 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[edit]


  1. ^ BESIII Collaboration (17 Aug 2009). "Charm Factories: Present and Future". AIP Conf.Proc.1182:406-409,2009. 
  2. ^ Minnesota BES-III home page