Application of RF direct sampling technology for beam diagnostics

Abstract In particle beam diagnostics, analog down-conversion structures have been widely used, particularly in systems such as cavity Beam Position Monitors/Beam Arrival Monitors (BPM/BAM) for Free-Electron Lasers (FEL) and bunch-by-bunch feedback systems in storage rings, to process GHz frequency signals. However, the integration of numerous analog components in the RF front-end module can negatively impact system performance, increase design complexity, and raise costs. To overcome these challenges, direct digitization of the RF signal for processing in the digital domain has become a key objective in modern beam diagnostics electronics. This paper presents the development of an RF direct sampling processor, featuring an analog-to-digital converter (ADC) with a bandwidth of 9 GHz and a sampling rate of 2.6 GSPS. The processor serves as a prototype for processing cavity BPM/BAM signals in FEL systems and hybrid BPM signals in bunch-by-bunch feedback systems. Upon final development, this RF direct sampling processor will enable independent, high-performance signal processing without the need for a front-end module, thus improving overall system efficiency. This innovation represents a significant advancement in the field of particle beam diagnostics, with potential applications in FEL and synchrotron radiation facilities.