• 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.

• M.-S. Yeh, L.-H. Chang, L.J. Chen, F.-T. Chung, K.T. Hsu, M.-C. Lin, C.H. Lo, Ch. Wang
  NSRRC, Hsinchu

The quasi-constant current operation is achieved in the NSRRC by periodically injecting electrons from the booster to the storage ring. It means the booster RF system keeps running during operation period, even the injection period occupies only a small portion of the total operation time. To benefit both the energy saving and klystron life, an energy saving controller has been developed and integrated into the TLS booster RF system. The cathode current of the klystron is decreased during the top-injection period. The energy consumption is thus dramatically reduced. A continuous record since the beginning of 2009 shows this controller can save about 78 percent of energy consumption of the booster RF system during normal operation. An overview of the control architecture and its functionality is presented herein.

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

To improve the reliability of a contemporary synchrotron as light source, a diagnostic system is crucial. A satisfactory diagnostic system must enable a clear presentation of the reason for a system fault, and provide sufficient information to the data analyzer for system recovery and improvement. To identify a fault and to monitor the operation of a RF system, many diagnostic utilities have been adopted. The architecture for the diagnostics of the TLS RF system is here reported.