Crystal Detector Based on Rubidium-87: Hunting for Traces of Sterile Neutrinos
Ordinary table salt on the kitchen counter seems inert, but inside its crystal lattice, events invisible to the eye can take place.
A Trap for the Invisible
Deep inside a mountain, where cosmic-ray muons are muffled by a thick layer of rock, stands a detector that catches not light but its absence. Positronium is a tiny atom in which an electron and its antiparticle, the positron, circle each other like a pair of dancers. Usually they come together and vanish in a flash of two or three gamma quanta.