TH2167HE High-Efficiency Klystron for the Hi-Lumi LHC

The development and test results of a high-efficiency klystron (TH2167HE) designed to deliver over 350 kW of continuous-wave (CW) power at 400.8 MHz with an efficiency exceeding 70 % are presented. This collaborative effort between Thales AVS MIS and CERN focuses on designing and fabricating an upgraded version of the TH2167 klystron to meet the demands of the High Luminosity Large Hadron Collider (HL-LHC). The development of the prototype is partially funded by the European Union under the IFAST program. Key challenges such as side bands and Multipactor effects were addressed. The unit is now ready for final characterization in operational conditions, ensuring compatibility with existing infrastructure.