The subject of this thesis was to construct and test a digital radio-frequency control system for the superconducting Darmstadt electron accelerator S-DALINAC. The controller consists of two components, a low-frequency and a high-frequency module. The high-frequency module developed within this framework is constructed from modern integrated circuits that offer, besides enhanced high-frequency properties, a built-in temperature stabilization. Currently, three superconducting cavities are controlled by the new modules via level converters, thus proving the suitability, and reliability in operation. A new low-frequency module was also commissioned during the course of the present work. It is based, in contrast to the existing control loops, not on analogue but on digital signal processing provided by fast Field Programmable Gate Arrays (FPGA). The fast signal processing capabilities of the new low-frequency unit enabled the implementation of a new, compared to the existing circuit, more advanced control algorithm for the digital control. Within this algorithm integral controllers were added to the proportional controllers in the amplitude as well as in the phase control loops. The digital control can now correct smallest residual errors that could not be compensated by the existing proportional controllers. Additionally, the phase control range was increased to ±180° by the implementation of a vector rotation. Spurious fix points of the control loop were prevented by a modified amplitude modulation. With these two components, namely, the high- and low-frequency module, the first digital radio-frequency control loop for the S-DALINAC was realized and successfully tested, operating on a superconducting cavity. Under typical operation conditions, an amplitude stability of 2.5·10−4 and a phase stability of 0.28° were emonstrated. Compared to the current control loops this implies an improved amplitude stability by a factor of 8, while the phase stability remains approximately unchanged. To achieve the required amplitude stability of 8·10−5 further improvements to the control algorithm are needed. Within the framework of this thesis, an universal and modular data acquisition system was put into operation, being the basis of an active energy stabilization system for the electron beam by means of time of flight analysis. The required analysing system was designed and installed. First tests showed that relative energy shifts of 7.6·10−5 can be measured reliably. Meanwhile, the modular data acquisition system is used for diagnostic purposes and for the processing of additional signals. These include the acquisition of beam currents, the monitoring of temperatures and the control of the high-voltage platform. | English |