Recent activities and developments for science and applications at the CERN neutron time-of-flight facility n_TOF

Neutron induced reactions have been, and still are, of paramount importance in many areas of research activities, ranging from basic nuclear science, to astrophysics, to applied nuclear technologies.

Conceived by Carlo Rubbia in the late ‘90s, the neutron time-of-flight facility, n_TOF at CERN, is poised to celebrate its 25th year of operation in 2026. The success of the research activities at n_TOF is deeply rooted in the unique characteristics of the neutron beams it provides, blending exceptionally wide neutron energy spectrum and resolution with high instantaneous flux. This combination allows for a wide array of neutron-induced reaction experiments, yielding crucial fundamental data for nuclear astrophysics, advanced nuclear technologies, and basic nuclear science. Currently, n_TOF operates three distinct experimental areas: two dedicated to time-of-flight measurements at 185 and 20 meters (EAR1, EAR2), and a third at 5 meters (NEAR) designed for neutron irradiations and activation studies. This diverse configuration effectively balances the demands for energy resolution and neutron beam intensity, both essential for neutron-induced nuclear reaction experiments.

The research conducted at n_TOF on neutron-induced reactions provides invaluable insights into astrophysics, particularly in unravelling the origins of chemical elements in the universe, notably through the study of the slow neutron capture nucleosynthesis (s-process). n_TOF routinely generates nuclear data with unprecedented accuracy across broad energy ranges, data that are instrumental in driving innovation in advanced nuclear technologies across various scientific disciplines. Looking ahead, planned upgrades will significantly enhance the facility's capabilities, opening doors to new research areas such as space technology and fusion science.

Furthermore, the n_TOF Collaboration is actively exploring the opportunities presented by the upcoming CERN SPS Beam Dump Facility (BDF). This facility will enable the expansion of activation measurements, a core component of neutron-induced reaction studies. The recently endorsed BDF will produce ultra-high neutron fluxes across a broad energy spectrum. These neutrons, when appropriately filtered and combined with a pneumatic rabbit system, will facilitate the measurement of neutron-induced activation cross sections on short-lived radioactive nuclear species. This development is particularly exciting due to its potential synergy with the radioactive ion beam facility ISOLDE, enabling collaborative studies on nuclear structure properties and neutron interactions with unstable nuclei.

A thriving community of over 150 scientists has coalesced around the n_TOF facility at CERN. The n_TOF Collaboration stands as a well-established and vibrant research community, deeply integrated within the broader nuclear physics landscape both in Europe and worldwide.