In the most recent run of BEPCII in dedicated synchrotron radiation mode, the Digital Beam Position Monitor (DBPM) electronics, developed by the Institute of High Energy Physics, operated successfully for the first time.
The DBPM was in stable operation for 12 days with the beam current ranging from 120mA to 250mA. The beam position resolution of closed orbit distortion (COD) in the vertical direction was about 3.17μm, with data acquisition from 12:00 a.m. on July 23 to 8:00 a.m. on July 24.
The beam position resolution results for the IHEP-developed DBPM (Image by IHEP)
Before connecting it to the Beam Position Monitor (BPM) system in BEPCII, the closed orbit response matrix of BEPCII was measured using the DBPM. The DBPM gain in the vertical direction was 0.93, with a measurement error smaller than 10%, which meets BEPCII requirements well.
Response measurement results for the domestically made DBPM (Image by IHEP)
As for the DBPM, its higher positon resolution was difficult to realize because of its complicated hardware and firmware. The DBPM group of IHEP has conquered all kinds of difficulties and made great progress in DBPM development over the past three-and-a-half years.
This is the first time a domestically developed DBPM has been used on an electron storage ring in China, proving that IHEP's DBPM can be put into service. It also lays a solid foundation for upgrading BEPCII's analog BPM electronics and for the upcoming High Energy Photon Source (HEPS) project.
Mr. Guo Lijun
International Office, IHEP