Next Generation LLRF Control and Monitoring System for S-Band Linear Accelerators

TL;DR

This paper presents a next-generation LLRF control system for S-band linear accelerators using RFSoC technology, achieving improved pulse stability and simplified architecture, validated through experiments and high-power tests at SLAC.

Contribution

Development and characterization of a novel RFSoC-based LLRF system for S-band accelerators, extending previous C-band designs with enhanced performance and simplified design.

Findings

Pulse-to-pulse fluctuation levels improved beyond requirements

Successful extension of RFSoC-based LLRF to S-band frequencies

High-power testing confirms system viability in accelerator environments

Abstract

The low-level RF (LLRF) systems for S-band linear accelerating structures are typically implemented with heterodyne base architectures. We have developed and characterized the next generation LLRF (NG-LLRF) based on the RF system-on-chip (RFSoC) for C-band accelerating structures, and the platform delivered the pulse-to-pulse fluctuation levels considerably better than the requirement of the targeted applications. The NG-LLRF system uses the direct RF sampling technique of the RFSoC, which significantly simplified the architecture compared to the conventional LLRF. We have extended the frequency range of the NG-LLRF to S-band and experimented with different RFSoC devices and system designs to meet the more stringent requirements for S-band LLRF applications. In this paper, the characterization results of the platform with different system architectures will be summarized and the high-power test results of the NG-LLRF with the S-band accelerating structure in the Next Linear Collider Test Accelerator (NLCTA) test facility at the SLAC National Accelerator Laboratory will be presented and analyzed.