Testing of the ESS MB-IOT Prototypes

ESS is considering the use of MB-IOTs for parts of the high-beta linac. Two prototypes have been built by industry, namely L3 and CPI/Thales and have passed the factory acceptance test with excellent results. Both tubes will go through further extensive testing at CERN for ESS following delivery and a final decision on tube technology will be taken in April 2018. This invited talk presents the background for the technical decision of IOTs vs klystrons, associated impact for ESS, and latest plans for industrial production of these IOTs for ESS.