Design and Prototyping of HL-LHC Double Quarter Wave Crab Cavities for SPS Test

The LHC high luminosity project envisages the use of the crabbing technique for increasing and levelling the LHC luminosity. Double Quarter Wave (DQW) resonators are compact cavities especially designed to meet the technical and performance requirements for LHC beam crabbing. Two DQW crab cavities are under fabrication and will be tested with beam in the Super Proton Synchrotron (SPS) at CERN by 2017. This paper describes the design and prototyping of the DQW crab cavities for the SPS test

Design of Dressed Crab Cavities for the HL-LHC Upgrade

The HL-LHC upgrade relies on a set of RF crab cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final geometry is provided along with an insight in the mechanical and thermal analyses performed to validate the design of this critical component. Emphasis is also given to material selection, prototyping, initial fabrication and test campaigns that are aimed at fulfilling the highly demanding tolerances of the couplers

Crab cavity and cryomodule development for HL-LHC

The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This paper overviews the main design choices for the cryomodule and its different components, which have the goal of optimizing the structural, thermal and electro-magnetic behavior of the system, while respecting the existing constraints in terms of integration in the accelerator environment. Prototyping and testing of the most critical components, manufacturing, preparation and installation strategies are also described