Ultrahigh spatiotemporal resolution beam signal reconstruction with bunch phase compensation

Abstract

Various electromagnetic signals are excited by the beam in the acceleration and beam-diagnostic elements of a particle accelerator. It is important to obtain time-domain waveforms of these signals with high temporal resolution for research, such as the study of beam–cavity interactions and bunch-by-bunch parameter measurements. Therefore, a signal reconstruction algorithm with ultrahigh spatiotemporal resolution and bunch phase compensation based on equivalent sampling is proposed in this paper. Compared with traditional equivalent sampling, the use of phase compensation and setting the bunch signal zero-crossing point as the time reference can construct a more accurate reconstructed signal. The basic principles of the method, simulation, and experimental comparison are also introduced. Based on the beam test platform of the Shanghai Synchrotron Radiation Facility (SSRF) and the method of experimental verification, the factors that affect the reconstructed signal quality are analyzed and discussed, including the depth of the sampled data, quantization noise of analog-to-digital converter, beam transverse oscillation, and longitudinal oscillation. The results of the beam experiments show that under the user operation conditions of the SSRF, a beam excitation signal with an amplitude uncertainty of 2% can be reconstructed.