Gaps and Needs in the Domain
In the PSE domain, Europe is presently at the forefront of research with world-leading Research Infrastructures like CERN, ESO, ESRF, ILL, European XFEL or ELI, and soon ESS, FAIR, CTAO, SKAO and hopefully Einstein Telescope, as well as with human exploration and permanent bases on the Moon and Mars. Nevertheless, Europe must remain vigilant to ensure that it has the means to maintain this leadership. In this perspective, some principal gaps and needs are identified below.
Over the last few decades, with the commissioning of the LHC in 2008 and the concomitant shutdown of the Fermilab Tevatron in the United States in 2011, CERN has consolidated its position as the undisputed world leader in the field of high-energy Physics. Since then, there is a worldwide tacit understanding that the global effort in Particle Physics at the energy frontier should focus on CERN facilities while America and Asia should deal with the main experiments at the intensity frontier, in particular the long baseline neutrino facilities. Some long-term initiatives are nevertheless explored in Europe in this field, e.g. in the ESSnuSB project. In order to keep this leadership in the future, Europe and CERN need to schedule as soon as possible the future machine to be hosted at CERN after the completion of the HL-LHC programme, which is supposed to end in the early 2040s. On the basis of the priorities identified by the Particle Physics community (see section A), the proposed reference scenario is the Future Circular Collider, with an electron-positron Higgs and electroweak factory as a first stage (FCC-ee) followed by a discovery hadron collider with a centre-of-mass energy of at least 100 TeV (FCC-hh). This scenario, which arose from Japan’s indecision since 2013 to embark on its ILC Higgs-factory project, will be scrutinised in the coming years for a possible decision in 2028.
Further theoretical research covering the full spectrum of Particle Physics should also be intensified, fostering links with Cosmology, Astroparticle Physics, and Nuclear Physics. This might open alternative pathways to new approaches towards revealing the nature of dark energy and dark matter. On this respect, another gap to be addressed is a ton-scale neutrinoless double beta decay experiment, which might be located in Europe and/or in Canada and is among the priorities of the US and European neutrino communities.
Another potential future gap to be underlined concerns the neutron scattering landscape. As underlined by the LENS consortium in its Neutron Science in Europe 2022 document, the world-leading ecosystem of neutron facilities in Europe has been created by decades of investment, but the landscape is now undergoing major changes. Many of the national reactor-based sources have closed, reducing European experimental capacity in the 2030s (when ILL is likely to reach the end of its operation) to around 60% of that available in 2019. At the same time, the world’s most innovative countries beyond Europe are planning to bolster their capacity and capability in this sphere. Some of these losses will be mitigated by the European Spallation Source and by the further development of existing sources. However, although ESS will be the most powerful neutron source in the world once fully operational, it will initially provide less than half the current capacity of ILL. The only route for entirely new facilities with significant capacity are High Current Accelerator-driven Neutron Sources (Hi-CANS), which could occupy the role played by national reactor-based sources in the past. Designs need to be demonstrated in practice through the realisation of an operational facility of this type.
More generally, to keep its world-leading position in the PSE domain, Europe needs to secure adequate and sustainable funding for the proper operation, maintenance and development of Research Infrastructures. Many PSE RIs require significant financial resources, with construction costs sometimes at the multi-billion-euros level (e.g. ESS and FAIR presently), and it is essential to secure funding of the whole PSE portfolio in the long run. Ensuring the education and training of new generations of technical and scientific staff is also crucial, as well as providing incentives for increased staff mobility between Research Infrastructures to allow the exchange of skills and foster collaborations between teams, institutions, and countries, which is a great tool for diplomacy. Administrative and legal procedures especially for the establishment of ERICs need to be streamlined and better adapted to the accession of international members and organisations.
The on-going war in Ukraine represents an additional risk and a source of concern, which could possibly lead to additional gaps and needs. Besides the generic side effects like the rise of inflation, the volatility of energy prices or the difficulties in the supply of some scientific equipment or fluids (e.g. semiconductors, helium), several PSE research domains have been particularly impacted by the freeze of the scientific collaborations with Russia. This is the case for Nuclear Physics, for which the JINR in Dubna was a major partner, providing enriched rare stable isotopes for many European Research Infrastructures in the field. The war has also led to the sudden loss of European access to Russian space launch capacity, adding on already existing restrictions on Europe’s independent launch capacity. The impact on CERN, whose Council decided to conclude cooperation with Russia and Belarus in 2024, is also severe with multiple impacts being mitigated on budgets, human resources and available expertise. In 2024, Russia is still a funding shareholder of ESRF, European XFEL (through the Kurchatov Institute) and FAIR (through ROSATOM), but without Russian scientists and experts benefiting of proper access to these facilities. Even if contingency plans are being put in place, this unstable situation is likely to jeopardise the operation model of these infrastructures in the upcoming years.
In most of the PSE Research Infrastructures, the original science case often evolves in substantial ways during the long life-time of the facility, requiring significant updates towards next-generation instruments. Preparing for such upgrades necessitates the implementation of continuous and lively dedicated R&D programmes. In this area, even if Horizon Europe is supporting rather well such programmes in a transverse way, there is presently a lack of funding opportunities to support specific high-budget R&D projects (from several million euros to several tens of millions of euros) specifically targeting the development of large-scale pioneering technological demonstrators or innovative scientific instruments (e.g. high efficiency, high repetition rate, high-power lasers, high-temperature superconducting magnets, energy recovery linac technology, next-generation optics for telescopes, beyond state-of-the-art detectors…). This gap should be addressed.
To encourage the establishment of public-private partnerships for innovative developments, it would be opportune to make European industry more aware of the opportunities and synergies offered by the PSE Research Infrastructures. The BSBF (Big Science Business Forum) events, which aim to promote collaboration between large scientific Research Infrastructures and industry, are a step in this direction. Another possible route for innovation would be to further promote the exchange of staff between universities, national research institutes, Research Infrastructures and industry to increase cross-fertilisation and foster mutual trust and effective engagement.
Finally, sustainability, including environmental impact and energy consumption, has become a central and crucial issue for all Research Infrastructures, especially in field of PSE and Energy. Each RI develops its own approach and contribution to the subject of sustainability. There is currently a lack of a forum for global information on the sustainability of RIs to measure and compare approaches and share good practices. The ‘Energy for Sustainable Science at Research Infrastructures’ (ESSRI) Workshop is an embryo of such a forum which could be more formalised and serve as a basis for a collective platform.