IHEP Beijing, Beijing
BEPCII is major upgrades of BEPC (Beijing Electron-Positron Collider). It is a double ring e±e collider as well as a synchrotron radiation (SR) source with its outer ring, or SR ring. As a collider, BEPCII operates in the beam energy region of 1-2.1 GeV with design luminosity of 1*1033cm-2s-1 at 1.89 GeV. As a light source, the SR ring operates at 2.5 GeV and 250 mA. Construction of the project started in the beginning of 2004. Installation of the storage ring components completed in October 2007. The BESIII detector was moved to the Interaction Region (IR) on May 6, 2008. In accordance to the progress of construction, the beam commissioning of BEPCII is carried out in 3 phases: Phase 1, with conventional magnets instead of the superconducting insertion magnets (SIM’s)n in the IR; Phase 2, with SIM’s in the IR; Phase 3, joint commissioning with the detector. The maximum luminosity reached to 2.3*1032cm-2s-1. This paper summarizes progress of the construction and commissioning in 3 phases, while focusing on the third phase.
* On behalf of the BEPCII Team
IHEP Beijing, Beijing
Funding: Work supported by National Natural Science Foundation of China contract 10725525
The upgraded project of the Beijing Electron-Positron Collider (BEPCII) can be operated not only for high energy physics experiments as a charm factory, but for synchrotron radiation users as a first generation light source. The design of the synchrotron radiation (SR) mode of the BEPCII storage ring keeps all the original beam lines of the BEPC. The lattice based on the layout of the collider can meet all the requirements of the SR users, and the emittance is minimized. Optimization of the SR mode focuses on reducing the effects from wigglers around the ring. Some results from the operations of the SR mode are also given.