Improving Beam-Based Regulation for Continuous-Wave Linear Accelerators with a Disturbance Model-Based Design

The present thesis is devoted to improving the temporal resolution of time-resolved accelerator-based experiments. Due to the fact that this temporal resolution is largely determined by the accelerator stability, specifically by the stability of the underlying electron beam, this work concentrates on the analysis, design and implementation of regulation algorithms in order to enhance the temporal stability of the electron beam. In this context, Chapter 2 investigates the problem of exploiting radio frequency noise for the purpose of modeling an electron beam disturbance. The investigation shows that a disturbance model that is based on the radio frequency noise may become
unnecessarily high-order, and even so, does not fully reflect the actual electron beam noise measured on the accelerator. Following this, Chapter 3 describes the design of a beam-based regulator that features a disturbance model that is derived from the measured electron beam noise data. The designed regulator is successfully evaluated on the continuous-wave linear accelerator ELBE. The presented results demonstrate that a single regulation stage, which is installed in a continuous-wave linear accelerator and features a disturbance model-based beam-based regulator, has a potential to outperform a commonly used proportional regulator, without compromising the plant stability. Finally, Chapter 4 presents a real-time feasible implementation of a high-order beam-based regulator that is ready to be employed for fast beam-based feedback.