Impact of and protection against failures of the LHC injection kickers

The LHC injection systems consist of horizontally deflecting steel septum magnets and vertically deflecting kickers. A mobile beam stopper is placed downstream of the kickers for setting up with single bunches and to protect the superconducting machine elements during normal injection in the event of a malfunctioning of the kickers. The effects of various potential kicker failures and their impact on the machine have been investigated. The injection parameters, the design principles of the stopper and additional protection measures are discussed.