Look Up At Particle Detectors

Whether deep underground or perched on a volcano, particle detectors help scientists to unravel the mysteries of the cosmos

- Brian Clegg

STRIKING GOLD

PROTODUNE, FRENCH-SWISS BORDER DETECTING: NEUTRINOS

Bathed in yellow light to avoid overstimulating its sensors, this neutrino detector is the size of a threestorey house. Neutrinos are abundant – trillions pass through you every second – but they hardly interact with matter, making them tough to detect. When in operation, ProtoDUNE is filled with 800 tonnes of liquid argon. Sometimes, a neutrino makes a direct hit on an argon nucleus, producing a trail of charged particles detected by grids of wires around the detector. This prototype is being tested at CERN’s headquarters, but DUNE (Deep Underground Neutrino Experiment) will be sited 1.5km underground in the disused Homestake gold mine in Lead, South Dakota. With four detectors, DUNE will pick up neutrinos generated by a particle accelerator 1,300km away at Fermilab, near Chicago. Expected to go live in 2026, DUNE will detect differences in behaviour between neutrinos and their antimatter counterpart, antineutrinos, which could help explain why the Universe has more matter than antimatter.

TANKS A LOT

HAWC (HIGH-ALTITUDE WATER CHERENKOV OBSERVATORY), MEXICO DETECTING: GAMMA RAYS