Researchers at the n_TOF experiment at CERN have reached a significant milestone in nuclear physics. The team successfully completed the first experimental measurement of the neutron capture probability of niobium-94. This isotope acts as a critical junction in the nuclear processes occurring within dying stars, where heavy elements are created.
The findings help clarify a long-standing mystery regarding the composition of ancient stardust. Presolar grains found in meteorites on Earth contain higher levels of molybdenum-94 than previous theoretical models could explain. By accurately measuring how niobium-94 captures neutrons at the EAR2 station, the team provided data that allows current stellar models to better account for these observed abundances.
The project involved a massive collaborative effort across international institutes. The IFW Dresden prepared the stable niobium-93 sample, the Institut Laue-Langevin converted it to niobium-94, and the Paul Scherrer Institute performed the characterization. The unique neutron flux at the CERN EAR2 facility then allowed the team to isolate the signal necessary for this specific measurement.
While this result solves a major portion of the puzzle, scientists acknowledge that further work is required. Future research will target the beta decay rate of niobium-94, the other path at this nuclear crossroads. Refining these measurements will provide a more complete understanding of the origins of heavy elements in our galaxy.