학술논문

Control of heavily-beam-loaded sns-ring cavities
Document Type
Conference
Source
Proceedings of the 2003 Particle Accelerator Conference Particle accelerator conference Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the. 5:3380-3382 2003
Subject
Fields, Waves and Electromagnetics
Engineered Materials, Dielectrics and Plasmas
Nuclear Engineering
Robotics and Control Systems
Delay effects
Feedback loop
Structural beams
Stability
Propagation delay
Control systems
RF signals
Three-term control
Demodulation
Delay estimation
Language
ISSN
1063-3928
Abstract
In each of four RF stations that make up the RF buncher system in the SNS accumulator ring, cavity voltage and phase are control led through a negative-feedback system employing digital electronics. With peak beam currents as high as 75 amperes near the end of each 1.1 ms machine cycle, the RF cavities in the SNS ring are strongly driven by the beam. To provide adequate regulation of cavity fields in the presence of high SNS beam currents, basic feedback loop parameters are pushed to levels where stability becomes a major concern. This note presents a LabVIEW simulation of the ring RF system that demonstrates how Smith compensation can be used to mitigate the destabilizing effect of dead-time delay in the feedback loop and assure adequate regulation of cavity fields. A digital implementation of Smith compensation is outlined that could be incorporated into the LLRF system being provided by BNL