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This chart

http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/alptun.html#c1

indicates that lower energy alpha particles have much longer half-lives. I am interpreting 'energy' to be a calculation based on the mass of an alpha particle and its velocity. So another way to read that graph might be to say that faster moving alpha particles have shorter half-lives. That is counterintuitive because a faster alpha particle will have more collisions per second and so should have a higher probability of being neutralized by an electron or captured by another atom.

So why do faster alpha particles live such short lives? A quote comes to mind from Lao Tzu — 'The flame that burns Twice as bright burns half as long.'

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  • $\begingroup$ you also forgot to mention the main reason why it might be counterintuitive at prima facie: higher energy particles should be moving closer to the speed of light and have longer, not shorter half-lives. Although we might outright discount that given that all alpha emitters I am aware result in particle speeds around 0.1c, so on the lower bound of what might be relativistically relevant $\endgroup$
    – lurscher
    Commented Jul 17, 2020 at 19:45
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    $\begingroup$ Alpha particles don't decay, so I don't think that is what you mean to ask. The link in your question is talking about the half-lives of alpha emitters as a function of the kinetic energies of their alpha particle daughters. $\endgroup$
    – J. Murray
    Commented Jul 17, 2020 at 19:53
  • $\begingroup$ Well, the nucleus that it comes from is less stable... $\endgroup$
    – Jon Custer
    Commented Jul 17, 2020 at 19:54
  • $\begingroup$ @J. Murray AHA!! So I interpret your answer as meaning that a high energy alpha particle and a low energy alpha particle will be detectable for equally long times. Please make that the ansswer so I can mark it so. $\endgroup$
    – aquagremlin
    Commented Jul 17, 2020 at 19:59

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Alpha particles are stable, and do not decay. The linked page is discussing the half-lives of radioactive nuclei which emit alpha particles, not of the alpha particles themselves.

Decays which release large amounts of energy tend to happen faster; this is manifested in the inverse correlation between the nucleus lifetime and the subsequent decay daughter's kinetic energy.

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