ESS, European Spallation Source, Lund (SE)



The European Spallation Source ESS in Lund (Sweden) is a research facility under construction that will produce long pulses of neutron radiation with very high intensity. In contrast to X-rays normally used in materials research, neutrons do not interact with the shell of electrons of the atoms of the materials under investigation. For this reason, it enables research into the structure and dynamics of materials at the molecular and atomic scale that is not possible with X-rays.

ESS will be the most powerful source of neutrons in the world and as such will offer unique opportunities for cutting-edge research into both applied and basic fields. Whether the aim is to probe the molecular composition of the materials of archaeological artefacts or of metal construction parts, analyse biomolecular processes, understand the electronic structure and dynamics of new superconductors, or identify the basic causes of parity violation in elementary particle physics, ESS will enable new discoveries and technological progress in these and other fields of research.

This international research infrastructure is based in Sweden and Denmark, and established under the legal form of a European Research Infrastructure Consortium (ERIC). Switzerland joined as a founding member of the ESS-ERIC on July 13, 2015, when construction began.

The costs of construction and operation of ESS until 2026 are expected to amount to some EUR 2.65 billion, of which EUR 1.84 billion will be spent on construction work (at 2013 prices). An initial phase of operations began in 2019, in parallel with the completion of infrastructure construction. It is estimated that full operation from 2026 onwards will cost around EUR 140 million per year.

In contrast to the traditional neutron sources (for example the source exploited by the Institute Laue-Langevin – ILL – in Grenoble), the neutrons at ESS are not produced through nuclear fission in a reactor, but through spallation by bombarding metal (Wolfram) with protons. In terms of both new technology and nominal performance, ESS enters unprecedented territories and great advances in the knowledge are expected.

Neutron sources are already in operation in the US, including HFIR (reactor) and SNS (spallation), Japan with JPARC (spallation), Germany, with e.g. FRM II and BER II (reactors), France with ILL (reactor) as well as Switzerland with SINQ (spallation). Because of its higher performance, the ESS will complement these facilities by opening up new research perspectives that cannot be addressed by current neutron sources.

Swiss participation

Switzerland has been involved in the planning of ESS and the construction work from the outset and will continue to take an active part in its operation. With the federal decree of 20 March 2015 on Switzerland's participation in ESS-ERIC, the Federal Assembly approved a total of CHF 130 million until 2026, corresponding to approximately 3.5% of construction and operation costs. This credit was increased by CHF 35.6 million with the federal decree of September 16, 2020. Swiss researchers and institutions, such as the PSI and EPFL, have already been prominent in the ESS planning phase and will continue to be actively involved in the future. Switzerland pays part of its contributions to ESS-ERIC in kind, in the form of components developed in Swiss research institutions.

Switzerland's involvement in ESS complements the investments in existing neutron source facilities both at the national level (SINQ) and international level (ILL), as a result of which Swiss researchers are ensured the best possible access to such leading research centres. The State Secretariat for Education, Research and Innovation (SERI) is responsible for Switzerland's participation in ESS.

As part of Switzerland's participation in ESS, Swiss industrial companies have the possibility to compete in ESS' invitations to tender. For further information, interested companies and institutions should contact ‘Swiss Industry Liaison Office'.


SERI, Xavier Reymond
Head of the Swiss delegation in the ESS-ERIC Council

Prof. Christian Rüegg
Scientific delegate representing Switzerland

SERI, Simon Berger
Swiss representative in the ESS-ERIC Finance Committee