Central to the HighNESS project is the design of a second neutron source for the European Spallation Source (ESS), to usher in an era of scientific research with high-intensity cold neutrons. These neutrons will be unique probes into matter, complementing those insights obtained by the ESS’s first neutron source. They could also answer questions in materials science and fundamental physics that have not been previously addressable at all.

Designing a second neutron source like this is not straightforward. Although many of the principles and materials involved have been tried and tested elsewhere, no-one has ever built a neutron source that operates at such high intensity over such a broad spectrum of neutron energies. Technical challenges abound. The design must be based not only on the latest research into neutron behaviour, but also on new simulations and measurements of neutron behaviour performed specifically for the HighNESS project. Different options must be considered, taking into account their relative costs and the constraints of the existing infrastructure, as well as the possible needs of future experiments in materials science and fundamental physics.

In presenting a design for a second ESS neutron source, HighNESS will help keep the European scientific community at the forefront of scientific progress. Nevertheless, it is important to the HighNESS partners that all the knowledge they gain is also made available to developers outside the project, for the development of other new neutron sources around the world.