Design of Temporary Beam Stops and Bunker Wall Plugs at ESS

The European Spallation Source (ESS) is currently under construction in Lund, Sweden. At the time of the first beam-on-target, foreseen in 2025, a first set of neutron scattering instruments will be commissioned, in addition to a test beamline for characterization of the source. For every planned beamline, all optics components will already have been installed in the monolith shielding surrounding the spallation target, but instruments will still be under construction in the neutron bunker area. Blocks of shielding, referred to as temporary beam stops or wall plugs, are then required to capture neutrons that will come out through the bunker wall feedthroughs during operation. This paper presents the results of parametric studies carried out to design temporary beam stops to assess the possibilities of reducing the weight and cost of such components and also to investigate the shielding efficiency of a wall plug as an alternative solution.