On 26 October 2026, the Paul Scherrer Institute (PSI) presented a method to speed up analysis of airborne measurements of radioactive sources. It separates gamma-ray scattering in the air from scattering inside the helicopter and analyses the full energy spectrum. In the model, a simulation that could take hours or days now takes only microseconds.
Researchers expect the method to distinguish weak barium and caesium sources within seconds in future, estimate their strength and locate them. This is a research result, not a report of a current radiation incident. The study was published online in «Nature Communications» on the same day.
Airborne measurements are difficult: few gamma photons reach the detector, while air and the helicopter’s metal surfaces alter their spectrum. Previous methods often grouped energy values. PSI’s approach combines faster physical simulations with Bayesian analysis of the complete spectrum.
Potential uses include emergency protection, monitoring nuclear facilities, geophysics and nuclear-material safeguards. PSI recalls flights near Mühleberg and Gösgen in May and June 2025 and an exercise with 140 participants from six countries, six helicopters and five drones. Those figures describe earlier exercises; the new method is presented as a tool for future analysis.