SNO+ Detects 50 Geoneutrinos in Western Hemisphere, Probing Earth’s Mantle
Updated
Updated · Quanta Magazine · Aug 7
SNO+ Detects 50 Geoneutrinos in Western Hemisphere, Probing Earth’s Mantle
1 articles · Updated · Quanta Magazine · Aug 7
Summary
SNO+ said its first geoneutrino detection in November 2025 added about 50 events, marking the first such measurements in the Western Hemisphere.
Those particles come from radioactive decay inside Earth, giving researchers a direct way to estimate heat-producing uranium, thorium and potassium in the crust and mantle.
Comparisons with Japan’s KamLAND and Italy’s Borexino suggest each site may be seeing different geoneutrino fluxes, raising the possibility that the mantle is chemically uneven rather than well mixed.
Large uncertainties still cloud that interpretation because scientists must subtract signals from reactors, cosmic backgrounds and nearby crustal rocks; SNO+ so far indicates a mantle beneath Canada that looks intermediate.
JUNO in China, with more than 20,000 tons of scintillator, is expected to report geoneutrinos later this year and could outcount the three earlier detectors combined.