L3 L6200 Multibeam IOT for the European Spallation Source

L3 Electron Devices has developed a high-power multibeam inductive output tube (MBIOT) for the European Spallation Source. In July 2014, L3 was awarded a contract for the design, manufacture, and test of a 1.2 MW, 704.42 MHz, pulsed power MBIOT. In October 2016, factory acceptance testing of the L6200 1.2-MW MBIOT was completed at L3 Electron Devices. In October 2017, site acceptance testing was successfully completed at the European Organization for Nuclear Research (CERN). The ten-beam, permanent magnet-focused device meets the maximum 1.2-MW output power specification with a dc-to-RF efficiency of 70%; efficiency is maintained above 60% down to 650 kW. Factory testing at L3 was limited to a cathode voltage of 43.6 kV and a maximum pulsewidth of 200 μs. The CERN MBIOT test stand enabled operation at the preferred cathode voltage of 45 kV and at the full pulsewidth of 4 ms. The CERN test stand also offered the ability to individually adjust the filament voltage and bias voltage to each gun, which was not possible with the L3 test configuration. The CERN test stand and MBIOT are currently being prepared to demonstrate long-duration operation.