PXIe-based LLRF architecture and versatile test bench for heavy ion linear acceleration

TL;DR

This paper presents a versatile digital Low-Level RF control system for heavy-ion accelerators, implemented on a PXIe platform with real-time control, IQ modulation, and adaptable sampling techniques, demonstrated on a prototype test bench.

Contribution

It introduces a flexible, high-performance LLRF architecture using PXIe hardware and LabVIEW, suitable for heavy-ion accelerator applications with real-time digital control.

Findings

Successful implementation of an 80MHz CW LLRF test bench

Versatile control using direct sampling and undersampling techniques

Real-time amplitude, phase, and frequency control of RF cavity

Abstract

This work describes the architecture of a digital LLRF system for heavy-ion acceleration developed under the specification of the projected future heavy-ion accelerator facility in Huelva, Spain. A prototype LLRF test bench operating at 80MHz in CW mode has been designed and built. The core LLRF control has been digitally implemented on a PXIe chassis, including an FPGA for digital signal processing and a real time controller. The test bench is completed with a good quality signal generator used as master frequency reference, an analog front end for reference modulation and signal conditioning, small RF components completing the circuit, as well as a tunable resonant cavity at 80 MHz, whose RF amplitude, phase and frequency are real-time controlled and monitored. The presented LLRF system is mainly digitally implemented using a PXIe platform provided by National Instruments, and is based on IQ modulation and demodulation. The system can be configured to use both direct sampling and undersampling techniques, resulting thus in a high performance and versatile RF control system without the need of excessive computational resources or very high speed acquisition hardware. All the system is programmed using the LabVIEW environment, which makes much easier the prototyping process and its reconfigurability.