GANIL (Grand Accélérateur National d'Ions Lourds) started the operation of the SPIRAL2 superconducting linac in 2022. Experiments in the Neutron For Science (NFS) room, specific beam dynamics studies and different technical improvements are carried out during its operation in the second half of each year, after the run of the cyclotrons in the first half of the year. Up to now, accelerated particles are mainly D+ and 4He2+ beams with energies between 7 and 20 MeV/A. First linac tunings with 18𝑂6+ and 40𝐴𝑟14+ ion beams at energies between 7 and 14.5 MeV/A were also carried out to prepare the Super Separator Spectrometer (𝑆3) experimental area commissioning. The paper presents a summary of the beam time distribution during the second year of operation, preliminary results of specific studies on cavity failure recovery and on pressure variation in the warm linac sections induced by beam losses.

Reliability is an important feature for high power particle accelerators. This is particularly true for Accelerator-Driven Systems (ADS), for that every beam interruption can strongly affect the availability of the nuclear reactor. Many of these outages come from the loss of accelerating cavities or of their associated systems. Cavity failures can be compensated for by retuning other cavities of the linac. Finding the ideal compensation settings is however a difficult challenge that involves beam dynamics and multi-objective optimisation, and which raises very different issues according to the linac under study. For instance in the SPIRAL2 linac, a lot of cavities are mobilized for the compensation and the search space has a very high number of dimensions. Plus, it has quite low margins on the longitudinal acceptance. Linacs for ADS (such as the Japan Atomic Energy Agency ADS or MYRRHA) have a specific fault-tolerance design which facilitate the optimisation, but cavities have to be retuned in a few seconds. Hence we developed LightWin, a tool to automatically and systematically find compensation settings for every cavity failure of any given linac. In this study, we will present LightWin’s latest developments as well as the compensation strategies that we developed for SPIRAL2 and ADS linacs, both from a beam dynamics and a mathematical point of view.