On Pavel Cherenkov's birthday anniversary, the discovery of Cherenkov radiation—the blue glow produced when charged particles travel faster than light through a medium—is revisited. This 1958 Nobel Prize-winning breakthrough is used today by Nuclear Safeguards Inspectors to analyse nuclear material. Cherenkov radiation is a form of energy perceived as a blue glow emitted when electrons and protons move at speeds faster than light in a specific medium.

While nothing exceeds light speed in a vacuum, particles can surpass light slowed in mediums like water. When charged particles move faster than light in water, they perturb atomic energy equilibrium, releasing photons that create a shock-wave of visible light. The high energies involved produce high-frequency, short-wavelength photons, typically violet and blue.

Cherenkov radiation occurs in radioactive materials immersed in water, including the water surrounding nuclear reactor fuel. Nuclear material, a by-product of energy production, can also serve weapons purposes. The IAEA verifies that nuclear material and facilities remain in peaceful use using specialized Cherenkov viewing devices.

These inspectors measure radiation in spent fuel storage ponds to compare reported data against declared information, ensuring safeguards compliance.