Non-Invasive Machine Parameters Measurement in a Storage Ring Based on Bunch-by-Bunch 3d Position Data Correlation Analysis
X.Y. Xu, Y.B. Leng
SSRF, Shanghai, People’s Republic of China
X.Y. Xu
University of Chinese Academy of Sciences, Beijing, People’s Republic of China
X.Y. Xu
SINAP, Shanghai, People’s Republic of China
In order to improve machine performance, the machine parameters of the storage ring (including optics parameters and insert devices parameters, etc.) need to be accurately measured. It is difficult to measure them with traditional methods during the user operation run. The behaviour of each bunch in the ring will not be exactly the same, but has its own personality (different transverse positions, longitudinal phases and different bunch charges). If the bunch-by-bunch 3D position can be accurately measured, every individual bunch can be used as probes to extract the dynamics parameters of the storage ring. Based on a broadband oscilloscope with a high sampling rate, a bunch-by-bunch three-dimensional parameter measurement system was built at the Shanghai synchrotron radiation facility(SSRF). The measurement uncertainty of longitudinal phase is less than 0.2 ps, the uncertainty of transverse position is less than 10 um and the charge uncertainty is 0.3% under the condition that the bunch charge is 600 pC. A general software package was developed to process the bunch signals and extract bunch parameters. The functions of this software package mainly include three-dimensional position, charge extraction, refilled charge signal stripping, and cable reflection signal stripping. Using this software package, the injection transient process was studied and the momentum contraction factor, dispersion function, and longitudinal damping oscillation parameters measurement were realized during the normal operation at SSRF. Because the software package does not require special acquisition equipment and does not have strict requirements on the state of the accelerator, the software package can be widely used in the bunch-by-bunch measurement of all ring accelerators.
Right click on video for Picture-in-Picture mode or Full screen display.
