Electron cloud studies for alternative train congurations and bunch spacings at the HL-LHC

The High Luminosity LHC (HL-LHC) has the ambitious goal of delivering an integrated luminosity of 3000 fb-1 in 10-12 years. The main potential issues that could undermine optimum performance with the baseline bunch spacing of 25 ns are, in particular, beam-beam eects, excessive pile-up events in the detectors and electron cloud build up. Several lling schemes aiming to reduce the rst two eects have been suggested. An analysis of the associated electron-cloud induced heat load in the arc dipoles has recently been carried out in order to assess their feasibility. In this note we describe the dierent lling schemes, compare their integrated luminosity performance with the baseline 25-ns scenario and present the results of pertinent electron-cloud studies.