Around 450 researchers and technicians will need to be employed in order to operate the ESS facility. Guest researchers from around Europe, visiting ESS in order to perform their experiments, will only stay for short periods. They will have to compete for research time at ESS. Only the best projects are allocated research time.

Today, there are around 5000 European researchers who use neutron scattering in their work. However, since neutron scattering will acquire a much broader range of application in the future, this number can change.