State-of-the-art cryogenics process control for the operation of the ESS superconducting linac

This paper presents the strategy for the simultaneous cryogenic operation of the ESS superconducting linac, consisting of 43 cryomodules. It details the process logic required for different operational phases and introduces a novel control system designed to manage these complexities. Key features of the system are discussed, including multiple independent automatic control sequences, a master controller for system synchronization, failure response protocols, and operator interface design. Fully deployed in December 2024, the system played a critical role in the successful cooldown of the accelerator. The paper also addresses lessons learned during this deployment and outlines potential improvements for future operations.