annihilation radiation

noun

Physics.

1. electromagnetic radiation produced by the coalescence and mutual annihilation of an atomic particle and its antiparticle, generally a positron and an electron, each pair forming two photons having a minimum energy of 0.5 million electron volts each.

Word History and Origins

Origin of annihilation radiation¹

First recorded in 1960–65

Example Sentences

Then they tracked the resulting annihilation radiation at the farthest edges of their experiment, using two photomultiplier tubes, anthracene crystals and a scintillation counter as a gamma-ray detector.

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