• L.-H. Chang, F.-T. Chung, M.-C. Lin, Y.-H. Lin, C.-K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
  NSRRC, Hsinchu

The direct RF feedback has been adopted in storage ring to reduce the beam loading effect for maximizing the stored beam current. Its performance in reducing beam loading is determined by the operational parameters, including the feedback gain, RF phase shift and the loop delay time. This paper presents a mathematical method, based on the Pedersen model, to study the effects of the direct RF feedback on beam loading. Through an example, the influences of different operational parameters on the performance of the direct RF feedback is analyzed by examining the characteristic equation of the feedback loop. The Nyquist criterion is applied for the determination of system stability.