SuperKEKB vacuum system operation in the last 6 years operation

The operation of the SuperKEKB has been ongoing since 2016. vacuum systems main ring (MR) which consists a 7-GeV electron (HER) and 4-GeV positron (LER), damping (DR) for 1.1 GeV positrons in middle injector linac have working well as whole. As June 2022, maximum stored beam currents MR are 1.46 1.14 A LER HER, respectively, approximately 30 mA DR. pressure increase per unit current is steadily decreasing new components developed expected. No significant cloud effect observed after installing solenoids drift spaces 2017 apply magnetic fields direction. recent behavior with increased explained by considering thermal gas desorption induced photon-stimulated desorption. Currently, lifetime primarily limited Touschek rather than pressure, their degrees contribution evaluated. challenges associated high currents, such damage to beam-collimator heads excess heating pipes at wiggler sections become more apparent increased. status system experiences during past 6 years presented here.27 MoreReceived 5 October 2022Accepted 7 December 2022DOI:https://doi.org/10.1103/PhysRevAccelBeams.26.013201Published American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this work must maintain attribution author(s) published article’s title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasBeam instabilitiesCryogenics & technologyVacuum technologyAccelerators Beams