Recommended modifications of the ESS baseline architecture for ESSnuSB

This report is a summary of measures, which should to be taken in order to enable the operation of the ESS linac as 5 MW proton driver for the ESSnuSB initiative in addition to its regular operation as 5 MW ESS proton source. An assessment of this option was made during a visit by F Gerigk (CERN) and E Montesinos (CERN) to ESS on 24 – 25 June together with staff members of ESS. The visit took place on the initiative and with the support of the University of Uppsala (Tord Ekelöf). We are very grateful to Yogi Rutambhara and Dave McGinnis who organized our visit at ESS and who made it possible for us to discuss with the relevant ESS experts and work package leaders. In the following we start with the charge to the committee, the considered scenarios for ESSnuSB, an executive summary containing a list of 9 recommendations and then a detailed list of findings, comments and recommendations ordered by subject.