A proposal for a scientific and technical R&D facility based on a recirculating superconducting linac is under active development at CERN. The conceptual design of this facility allows for a staged construction with a number of well-defined intermediate steps, leading to an ultimate beam energy of about 1 GeV. Aside from various other technical and physics goals and applications considered, this ERL facility, in particular, aims at investigating the ERL principle, including its specific beam dynamics, operational and reliability issues as relevant for the LHeC, and at providing a test stand both for superconducting (SC) RF cavity modules and for controlled beam induced quenches of SC magnets.
A sketch of the ERLTF conceptual configuration is provided in the figure below. It shows a principal structure of two parallel linacs comprising two 4-cavity cryomodules each to achieve 150 MeV acceleration per Linac and pass. There are up to three passes. Possibly there will be a pre-acceleration unit following the source to enter the ERL with already relativistic electrons (>5 MeV).
First considerations and studies of the optics and magnet configurations etc. have been launched within the BE-ABP group, first studies of the cavity and cryomodule are about to start with a CERN fellow in the BE-RF group. A complete conceptual design of the ERLTF, including rigorous beam dynamics studies, will yet require more time and effort and comprises the RF system, the injector, the dump, the optics system, the instrumentation, the beam dynamics and first cost and schedule studies. The 4-cavity cryomodule is considered central and should be prototyped during this first design stage to allow verification of its performance reach.