The full-energy beam injection system from SACLA to the SPring-8 storage ring has been developed. Low-emittance beam injection is required for the future upgrade of SPring-8 due to its small injection beam aperture. The electron beam injection from an X-ray free-electron laser linear accelerator not only satisfies the emittance requirement but also it confers a cost benefit compared to a conventional dedicated injector system. In SPring-8, the SACLA linear accelerator is now delivering X-ray free-electron laser photon beams and serving as a full-time injector of SPring-8 in parallel.2 MoreReceived 13 August 2021Accepted 11 October 2021DOI:https://doi.org/10.1103/PhysRevAccelBeams.24.110702Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeam injection, extraction & transportBeam opticsBeam optics transportPhysical SystemsFree-electron lasersSynchrotron radiation & free-electron lasersSynchrotron radiation facilitiesAccelerators & Beams