IFJ PAN’s contribution to the HL-LHC: DQW crab cavity preparation and testing at CERN

The Double Quarter Wave (DQW) Crab Cavity was designed to rotate the colliding bunches and in consequence to increase the luminosity of the LHC machine. Prior to launching series production detailed RF validation tests, both without and with beam, were performed at CERN. For the cavity preparation and RF performance validation before installation in the cryomodule, a comprehensive programme of RF surface preparation and cavity performance evaluation in liquid helium temperatures were carried out. Due to the unusual geometry of the DQW cavity there were a number of challenges both in preparation and RF testing that had to be addressed. The results and conclusions of the preparation process and cavity performance in the vertical test cryostat are presented in this paper in the form of a short technical report.