CERN’s n_TOF facility reported the first experimental measurement of neutron capture by radioactive niobium-94. The result matters because niobium-94 is part of a pathway scientists use to understand molybdenum-94 found in presolar grains. CERN’s page, dated August 19, 2026, describes the first experimental determination.
What n_TOF measured
The measurement focused on the neutron-capture cross section of niobium-94. A cross section describes how likely a nuclear reaction is under different neutron energies. The team used a time-of-flight technique, which infers neutron properties from how long particles take to travel a known distance.
How niobium-94 connects to molybdenum-94
The reaction pathways described for niobium-94 lead to different products: neutron capture produces niobium-95, while beta decay produces molybdenum-94. That second route matters to a puzzle in presolar grains, stardust preserved in primitive meteorites. For about two decades, models have struggled to reproduce the molybdenum-94 abundance observed in those grains.
Measuring one route can sharpen a stellar model without accounting for every process that shapes an isotope’s abundance.
What the measurement changes in stellar models
Javier Balibrea Correa, identified as the study’s first author, said that adding the measurement reduces uncertainty in advanced stellar models and helps them reproduce the molybdenum-94 abundance seen in ancient stardust. Other nuclear processes involving niobium-94 still rely on theoretical estimates, so the result addresses part of the abundance puzzle rather than settling it.
