A novel microwave switch-based LLRF system for long-term system phase drift calibration

Abstract

Long-term phase stability is a significant issue for Low-level RF systems. Crosstalk and temperature effect on the RF field detectors would significantly limit the performance of phase detecting and phase locking. A novel microwave switch-based LLRF system has been developed in Tsinghua Accelerator Lab. Microwave switches are applied in the chopper circuit to turn continuous waves into pulse waves in the time domain to avoid mutual interference of signals. In this paper, the LLRF sys-tem based on microwave switches is presented. The result of preliminary long-term experiments shows the phase stability can achieve about 50fs RMS slow drift. The peak-to-peak value of the slow drift was ~100fs (~2 °C p-p) in 4 days.