The low level radio frequency control system for DC-SRF photo-injector at Peking University

TL;DR

This paper presents the design and implementation of a low level RF control system for a 2K DC-SRF photo-injector at Peking University, achieving high stability in amplitude and phase for both CW and pulsed operations.

Contribution

The paper introduces a reliable LLRF control system capable of operating in GDR and SEL modes, with precise amplitude and phase stability for DC-SRF cavities.

Findings

Achieved 0.13% amplitude stability

Achieved 0.1° phase stability

System works reliably in GDR and SEL modes

Abstract

A low level radio frequency (LLRF) control system is designed and constructed at Peking University, which is for the DC-SRF photo injector operating at 2K. Besides with continuous wave (CW), the system is also reliable with pulsed RF and pulsed beam, the stability of amplitude and phase can achieve 0.13% and 0.1{\deg}respectively. It is worth noting that the system works perfectly when the cavity is driven at both generator driven resonator (GDR) and self-excited loop (SEL), the latter is useful in measuring the performance of the cavity.