First Years of Linac4 RF Operation

Following the construction, commissioning, run-in, and connection, in 2021 Linac4 at CERN saw its successful start-up to full operation. Being composed primarily of RF systems, occupying most of the tunnel and the equipment hall, a coordinated effort has been put in place by four RF teams providing cavities, amplifier chains, low-level RF and general control systems. While all parts came together with impressive performance from day one, many details required a considerable debugging effort to achieve the requested availability of at least 95% from first operation in the synchrotron complex. This contribution focuses on issues in equipment reliability, radiation to electronics, thermal stability, systems interaction, as well as a few aspects of complex low-level RF setup. It will also discuss decisions taken with respect to spare policies and upgrades for the coming years.