S. Mertens

Radioactive tritium decays, emitting an electron. Its energy is almost always the same, but sometimes, just a little less. This shortfall could mean that alongside the ordinary neutrino, another, hidden particle was born. The Standard Model describes three types of neutrinos, but scientists suspect there is a fourth — the sterile one.

Inside the detector, which resembles a large thermos filled with germanium, faint flashes are born. Neutrinos, tiny particles that barely interact with matter, occasionally bump into germanium nuclei. The nucleus recoils, and the detector registers the jolt. But to distinguish a real signal from noise, the instrument needs precise calibration.