Thorium-229: How to Hear a Nucleus in an Opaque Crystal
A thin film of thorium dioxide, just 10 nanometers thick, is deposited on a steel disk. A laser pulse strikes it, but instead of the expected glow, the detector catches a stream of electrons.
Crystalline Acoustics of a Nuclear Whisper
Thorium-229 harbors a secret: its nucleus possesses the lowest excited state among all known nuclides — 8.35 eV.