Experiment

Cowan-Reines Neutrino Experiment

Savannah River Plant, South Carolina, USA · 1953–1959

Objective

First direct detection of the free antineutrino via inverse beta decay on protons.

Method

A tank of cadmium-loaded water sandwiched between liquid-scintillator detectors, placed beside the Savannah River reactor. The delayed coincidence between the positron annihilation and the neutron capture on cadmium tagged the signal.

Key results

  • Observation of the delayed coincidence signature consistent with antineutrino capture.
  • Telegram to Pauli in 1956 confirming the detection.
  • Established the neutrino as an experimentally accessible particle.

Significance

Moved the neutrino from theoretical postulate to observed reality, laying the foundation for all subsequent neutrino experiments.

Placeholder experiment portrait during scaffolding.