Conditioning Experience of the ESS Spoke Cryomodule Prototype

The prototype cryomodule for the ESS double spoke cavities is tested in the FREIA laboratory at Uppsala University. One of the goals of this test is to establish an efficient way to assess one series cryomodule within a due time (about one month). In 2017, the dedicated high-power test for dressed cavities in the horizontal cryostat (HNOSS) revealed that one of the possible challenges is a conditioning process of the coupler and cavity multipacting. Each process should not damage any components of the cryomodule but at the same time it should be finished in a reasonable time scale. More importantly, unlike the previous tests in the vertical or horizontal cryostat, conditioning two cavities in one cryomodule in due time may require parallel processing in some part of the procedure. This study will be the first practical experience of double spoke cavity conditioning in a cryomodule, and will lead to a standard conditioning recipe for future projects containing superconducting spoke cavities. In this presentation, a preliminary result of cryomodule testing will be shown with a special focus on the conditioning processes.
Proceedings of the 19th International Conference on RF Superconductivity, SRF2019, Dresden, Germany