Pulsed sextupole injection for Sweden’s new light source MAX IV

The MAX IV facility presently under construction will include two storage rings for the production of synchrotron radiation. Both rings will be operated at a constant 500 mA of stored current with top-up shots supplied by the MAX IV linac acting as a full-energy injector. Until recently, injection into both storage rings was designed using a conventional approach: a closed four-kicker injection bump brings the stored beam to the septum blade where the injected bunches are captured in a single turn. This method, although commonly found in third generation light sources, has significant disadvantages. Therefore, an alternative injection into the storage rings using pulsed multipoles has been investigated. This type of injection does not require an injection bump and has the potential to make top-up injection fully transparent to users. Design studies have been successfully completed and as a consequence it has been decided to replace the originally foreseen conventional injection scheme with pulsed multipole injection in both MAX IV storage rings. This paper reports on these studies, presents pulsed sextupole injection schemes, and summarizes requirements for the pulsers, sextupole magnets, and vacuum chambers.