Hefei Light Source Beam Stability Measurement And Horizontal Analog Feedback

Brightness and stability are key specifications of synchrotron radiation light sources.Continual endeavor is directed to acquire high current,high brightness and favorable stability.Whereas the knowledge of coupling impedance(by which we mean the interaction between a beam and the surrounding vacuum chamber) indicates that the probability of improving performance of storage ring is limited by complicated beam surroundings.What caused the beam unstable,and how to cure the beam instabilities are the key questions,which all the accelerator researchers around the world need to face.Firstly,the HLS turn by turn measurement(TBT) system integration and application are introduced.A couple of system control software and data processing procedures are developed.The transient tune extraction based on NAFF algorithm and damping time calculating based on digital phased-locked amplifier are introduced. The measurement and calculation of the phase space are summed up and development, also,the x y coupling.Secondly,the HLS analog transverse feedback prototype has been improved. Analysis the existing problems of feedback prototype and proposed the following improvements:front-end signal processing module reconstruction;joined the DC component removed units;improved the signal vector resultant modules and added four high-frequency phase control modules;joined the XY feedback gain independent control module;fully optimize the signal transmission line,effectively solute the issue of signal reflection.This article has also developed a system based on the EPICS control software.Finally,a couple of experiments for HLS electron storage ring are conducted based on turn-by-turn measurement systems and improved analog transverse feedback system.This article also analyzed the influence of longitude oscillation to the transverse feedback system.For HLS electron storage ring,the growth and damping rate of Beta oscillation are given,the transient tune changed with time and corresponding changes in phase space are showed.This paper has also introduced the debugging of improved analog transverse feedback system at 200MeV injection status, and the injection beam instabilities phenomenon have been measured and analyzed.