A Compact Low-level RF Control System for Advanced Concept Compact Electron Linear Accelerator

TL;DR

This paper presents a novel compact low-level RF control system using RFSoC technology for advanced electron linear accelerators, achieving high stability and reduced size by eliminating analogue mixers.

Contribution

Introduction of a compact LLRF control system based on RFSoC with direct RF sampling, significantly reducing size and weight compared to conventional architectures.

Findings

Achieved magnitude and phase fluctuation below 1% and 1 degree.

Demonstrated stable control over 2 microseconds RF pulses.

Validated system performance with accelerator cavities.

Abstract

A compact low-level RF (LLRF) control system based on RF system-on-chip (RFSoC) technology has been designed for the Advanced Concept Compact Electron Linear-accelerator (ACCEL) program, which has challenging requirements in both RF performance and size, weight and power consumption (SWaP). The compact LLRF solution employs the direct RF sampling technique of RFSoC, which samples the RF signals directly without any analogue up and down conversion. Compared with the conventional heterodyne based architecture used for LLRF system of linear accelerator (LINAC), the elimination of analogue mixers can significantly reduce the size and weight of the system, especially with LINAC requires a larger number of RF channels. Based on the requirements of ACCEL, a prototype LLRF platform has been developed, and the control schemes have been proposed. The prototype LLRF system demonstrated magnitude and phase fluctuation levels below 1% and 1 degree, on the flat top of a 2 microseconds RF pulse. The LLRF control schemes proposed for ACCEL are implemented with a prototype hardware platform. This paper will introduce the new compact LLRF solution and summarize a selection of experimental test results of the prototype itself and with the accelerating structure cavities designed for ACCEL.