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Beam Instrumentation

The purpose of the Beam Instrumentation group is to measure and broadcast various parameters of the beam during the commissioning and daily operations of SSRF, helping the accelerator physicists and the operators detecting and monitoring the beam behavior by processing information like the position, the size and the charge.

The SSRF beam instrumentation system, consisting of 61 stripline BPMs, 152 button BPMs, 2 DCCTs, 11 Wall Current Monitors (WCM), 3 ICTs, 1 faraday cup, 18 screen monitors, 2 tune monitors, 3 transport line slits, 2 ring scrapers, 1 multi bunch feedback system, 1 filling pattern monitor and 1 dedicated diagnostics beam line, has been built for commissioning, operation and machine study. The data acquisition system for beam instrumentation is designed on EPICS platform, which follows “standard model” architecture. Five kinds of IOCs were used in this system: VME bus IOC, Libera embedded IOC, PXI bus IOC, scope embedded IOCs, and soft IOC.

The Beam Position Monitor system along with the Libera electronics from IT calculates the beam position information with various data rate from the raw ADC readings. The sum signals of the BPM, calibrated by the ICT, are used as a relative beam charge and transport efficiency measurement in LINAC and the sum signals calibrated by the DCCT are used as a beam current, beam lifetime and filling pattern measurement in the booster or the storage ring. The beam spectra calculated from the beam positions are used to monitor the betatron tunes and the resolutions are better than 0.001. The transverse feedback system along with the beam position monitors has been stabilizing the beam orbit during operations on the storage ring.

Two (horizontal and vertical) interferometers and an X-ray pinhole camera are equipped on the diagnostics beamline to measure the transverse beam sizes as well as the transverse emittances and a streak camera is used to measure the bunch length. A fast-gated camera has also been used on the beamline to study the transient process during injections.

ICTs from Bergoz and WCMs from TOYAMA are used in the LINAC or the transport lines to do absolute bunch charge measurements and longitudinal bunch distribution measurements respectively. DCCTs from Bergoz are used in the booster ring or the storage ring to do absolute beam direct current measurements. Profiles, scrappers and other beam diagnostic instrumentations are always ready in case there will be machine studies.

The performance of completed BI system is shown below:




The group is currently composed of 9 members.



Yongbin Leng


Kairong Ye


Luyang Yu


Renxian Yuan


Jie Chen


Zhichu Chen


Longwei Lai


Tong Shen


Sang Wu



Digital BPM Processor



The performance of completed BI system is shown below: