Beijing Electron-Positron Collider，BEPC, is a unique e--e+ collider operating in τ-charm energy region and also a synchrotron radiation source. It consists of an injector linac, transport lines, a storage ring, the Beijing Spectrometer (BES) and the Beijing Synchrotron Radiation Facility (BSRF). BEPC was completed and put into operation in 1988 in IHEP. Numbers of physics results have been obtained including τ-mass measurement, 2-5 GeV R-value measurement, and discovery of X (1835), and etc. As a major upgrading project of BEPC, BEPCII is a double ring e--e+ collider and a synchrotron radiation facility with its outer ring. BEPCII operates in the beam energy range of 1-2.1 GeV with the design luminosity of
at 1.89 GeV. As a light source, it operates at the beam energy of 2.5 GeV with the intensity of 250 mA. The project started construction in the beginning of 2004 and completed in 2008. Since then, the collider has been operated for both high energy physics and synchrotron radiation programs. It is expected that the nature of the τ and charm physics will be deeply explored with BEPCII.
