alpha ray

noun

Physics.

1. a stream of alpha particles.

alpha ray

noun

1. ionizing radiation consisting of a stream of alpha particles

alpha ray

1. A stream of alpha particles.

Word History and Origins

Origin of alpha ray¹

First recorded in 1900–05

Example Sentences

“Keeps out the alpha rays, Max! You don’t get old.”

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Eventually alpha rays were identified as helium atoms stripped of their electrons—that is, helium nuclei-—and beta rays as energetic electrons.

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He had named them alpha rays, but as he found he could not get them to penetrate even a thin sheet of paper, he was confident that they must be atoms of matter.

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If trapped inside the body, though, alpha rays can cause cancer.

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The alpha rays are projected particles which lose energy in penetrating matter.

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