Synergies for testing Superconducting RF cavities
Fig 1, left: XFEL series cavity during incoming inspection at DESY. Image credit: DESY
Fig2, right: Vertical test inserts equipped with XFEL superconducting accelerator series cavities. Image credit: DESY.
Within the 36 month period of the CRISP project the main objective of WP4 is to upgrade and harmonize the SRF Accelerator Structures for ESS, ILC, LHC upgrade and the European XFEL. The activity supports an optimised surface treatment, the application of advanced test and preparation infrastructure as well as state-of-the-art diagnostics tools.
At CERN the SRF cavity test infrastructure is under upgrade to allow 2 Kelvin operation needed for the characterisation of a first cryomodule for the ESS and the CERN-SPL. The upgrade includes a new cryogenic transfer line between the cryoplant and RF test stand area with two horizontal cryomodule test places and four vertical RF test cryostats. Two of the vertical cryostats have been modified for 2K operation, which is necessary for the testing of the SPL cavities.
The industrial production of the series accelerator cavities for the European XFEL started successfully beginning of 2013. Until end October 2013, 164 series accelerator and ILC-HiGrade cavities for the European XFEL have been delivered to DESY. For many of the cavities that didn’t pass the tests an additional treatment applying a chemical surface removal (“Buffered Chemical Polishing BCP”) is under consideration. The development of advanced diagnostics like high resolution optical inspection and the experience of industrial cavity production and surface treatment will be extremely beneficial for any other European large scale SRF project such as ESS as well as for the preparation of the ILC.
