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.
KEK, Ibaraki
LAL, Orsay
IHEP Beiing, Beijing
High power tests of the STF cryomodule including four MHI cavities and STF-1 input couplers were carried out at KEK. The maximum input rf power of 360 kW was successfully transfered to the cavity operated at high gradients at 2 K. After the cryomodule tests, the conditioning test of the coupler at room temperature was carried out, and rf processing up to 650 kW (1.5 ms and 5 Hz) was achieved. TTF-V couplers were shipped from LAL to KEK, and the high power test was carried out at KEK-STF. Rf processing up to 2 MW in the short pulse of 400 us (5 Hz) and 1 MW in the long pulse of 1.5 ms (5Hz) was demonstrated. The results of the coupler processing at KEK will be reproted in this talk.
