Beijing_Electron–Positron_Collider_II
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.[1]
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.[2] Operations began in summer 2008 and the machine has run at multiple energies.