An electron–hadron collider at the high-luminosity LHC

Abstract We discuss a concept of a lower-energy version of the Large Hadron–electron Collider (LHeC), delivering electron–hadron collisions concurrently to the hadron-hadron collisions at the high-luminosity LHC at CERN Assuming the use of a 20 GeV electron energy recovery linac (ERL), we report the results on the optimised beam dynamics, accelerator technologies, and detector constraints required for such a ‘phase-one’ LHeC. Finally, we also discuss the ERL configurations and the possibility of delivering electron–hadron collisions during the planned Run5 of the LHC, which opens excellent research capabilities—the unique scientific potential of the proposed facility is outlined.