alpha particle

noun

: a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations

called also alpha, alpha radiation, alpha ray

Examples of alpha particle in a Sentence

Recent Examples on the Web An alpha particle is made of two protons and two neutrons. WIRED, 8 Sep. 2023 The mass of an alpha particle is more than 7,000 times larger than that of a beta particle. WIRED, 8 Sep. 2023 This means that an alpha particle is a helium atom without the electrons. WIRED, 8 Sep. 2023 To that end, the Indian lander and rover carried half a dozen scientific instruments—a 10-centimeter probe to analyze the soil’s thermal properties, an alpha particle X-ray spectrometer and so forth. IEEE Spectrum, 29 Aug. 2023 For example, in 1928, while visiting the University of Göttingen in Germany, Gamow learned about a dilemma physicists faced in explaining the process of alpha decay, when a heavy nucleus such as uranium suddenly expels an alpha particle (a cluster of two protons and two neutrons). Paul Halpern, Scientific American, 18 Aug. 2021 In contrast, Convergent plans to use a protein in the immune system called antibodies to deliver radiation-emitting particles, and the radiation comes in the form of alpha particles, which Kantoff says are 1,000 times more powerful than beta particles. Jonathan Saltzman, BostonGlobe.com, 3 May 2023 Hence, current-gen console owners will likely want to opt for higher frame rates—and while both aforementioned consoles apparently hold close to 60 fps in performance mode, each can still dip into the mid-50s during intense sequences full of alpha particle effects. Sam MacHkovech, Ars Technica, 15 Feb. 2022 The fourth decay can occur by two different routes, with each path releasing one alpha particle and one beta particle before reaching lead-209. Jacqueline Detwiler, Popular Mechanics, 1 Feb. 2020 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'alpha particle.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1903, in the meaning defined above

Time Traveler
The first known use of alpha particle was in 1903

Dictionary Entries Near alpha particle

Cite this Entry

“Alpha particle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alpha%20particle. Accessed 3 Mar. 2024.

Kids Definition

alpha particle

noun
: a positively charged particle that is identical with the nucleus of a helium atom, consists of 2 protons and 2 neutrons, and is thrown at high speed from a radioactive atomic nucleus

Medical Definition

alpha particle

noun
: a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations

called also alpha, alpha ray

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