The Beijing Electron-Positron Collider (BEPC) has been well operated not only for high energy physics, but also for synchrotron radiation application for more than 15 years since 1989. Its upgrade scheme BEPCII is a double-ring collider which two beams have same energies. It aims at the research of t-charm physics with a designed luminosity of 1.0´1033 cm-2s-1, which is about two orders higher than BEPC at the beam energy of 1.89 GeV. The two new rings of BEPCII have been built in the existing BEPC tunnel while keeping the machine as a synchrotron radiation source. According to the requirements of high energy physics,BEPCII has been operated in a large beam energy region from 0.9 GeV to 2.5 GeV since 2009.
BEPCII has produced the world’s largest samples of J/Ψ and Ψ’events,as well as events at a range of 1.5 GeV to 2.5 GeV. Using these samples,the BESIII experiment has made important discoveries including the Zc(3900) and other so-called XYZ states. For synchrotron radiation experiments,up till the end of 2024 BSRF has supported over 12,000 experiments,leading to over 10000 publications.
The BEPCII upgrade project was approved in July,2021 according to strong requirements for the new high energy physics study. The upgrade scheme aims at increasing luminosity by a factor of 3 at beam energy of 2.35GeV and extending maximum beam energy up to 2.8GeV. The installation of upgrade project started on July 1,2024 and the commissioning started on Jan. 2,2025.
