CEA, Gif-sur-Yvette
Coaxial 704 MHz power couplers have been developed for high intensity superconducting proton linacs. Projects like the Superconducting Proton Linac (SPL) at CERN or the European Spallation Source ESS require up to 1 MW pulsed power with a high duty cycle in the high energy section of superconducting elliptical cavities. One pair of couplers has been successfully conditioned on the 704 MHz test stand at Saclay at room temperature at a maximum power of 1.2 MW, with 2 ms pulses and 50 Hz repetition rate, equivalent to10% duty cycle. In order to test the coupler in realistic conditions with its cryogenic environment, we prepare a cold test with a cavity in the horizontal cryostat Cryholab.
CEA, Gif-sur-Yvette
IFMIF is the future neutrons irradiation facility that aims to qualify advanced materials for the fusion reactors successor to ITER. The required neutrons flux is created from the irradiation of a lithium target by two high intensity deuteron ion beams (125 mA @ 40 MeV CW) produced by two parallel superconducting accelerators. The niobium cavities are Half Wave Resonators (HWR) at 175 MHz operating at 4.5K. All cavities are equipped with the same power coupler designed to transfer a maximum power of 200 kW in CW. The present phase of the project, IFMIF-EVEDA, is aimed to validate the technical options for IFMIF, by the construction of an accelerator prototype: 1 cryomodule with 8 HWRs and 8 couplers providing RF power up to 70 kW. Nevertheless, these couplers are designed to be able to operate at 200 kW, and they will be tested and conditioned at this power. This paper describes the overall operating requirements of these high power couplers, presents the main choices that have been made up to now and the RF design of the coupler components.
