Seeing Inside the Earth
Deep beneath our feet, within the planet's bulk, radioactive elements are slowly decaying. This process spawns tiny particles — geoneutrinos. They pass through the crust, mantle, and core, barely interacting with anything.
A Detector That Sees Helium Nuclei
An alpha particle is a helium nucleus that flies out when heavy atoms decay. When it hits a gallium nitride crystal, it deposits its energy and creates an electrical pulse. The pulse height tells you how much energy the particle had.
The Underground Guardian of Purity
A huge pool of clear liquid is hidden deep underground. Inside, there is nothing but a pristine 'broth' that flashes with faint light when an invisible particle flies through. This is the JUNO detector—20,000 tons of liquid scintillator built to hunt for neutrinos.
The main enemy of such a hunt is not darkness but its own noise.