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Simple questions about alpha particles

  1. Oct 6, 2004 #1
    1. Can any other atom besides helium be completely stripped of all its electrons? Are these ever encontered? Can they (C +12, or Fe +26, or U +92 etc.) be isolated and produced as a stream? How do these compare (stability) to alpha particles?

    2. As for alpha particles themselves, how long do they last before becoming helium? There must be some half-life related to this and that would depend on local environment, especially the pressure of the gas in which it resides. Surely, an alpha particle would last longer in a vacuum than it would in 1 atm.
  2. jcsd
  3. Oct 6, 2004 #2


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    A major factor in stripping electrons is the temperature. It is practical problem. For example at the center of the sun everything is completely ionized. Also gas density does play a role, as you indicated. In outer space electrons are sparse.
  4. Oct 7, 2004 #3
    Hydrogen atoms are often stripped of thier electron, its usually how we isolate a proton for use. Basis and Acids work on the principal of the Ionisation of A hydrogen atom.

    I couldnt tell you about the others... But yes i have heard that everything is completely ionised at the centre of a star. So id agree with that

    An alpha particle will only last going through a few mm of air before ionising... and into solid mattar about [tex]~10^-2mm[/tex]
  5. Oct 7, 2004 #4
    sorry, that was a few cm in air
  6. Oct 7, 2004 #5


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    As mathman said, yes - it depends upon things like temperature and pressure. These are encountered 'all the time' (e.g. in cosmic rays), and yes, they can be 'isolated and produced as a stream' (e.g. in many particle accelerators around the world; in fact, that's how the few super-heavy elements have been produced!)
  7. Oct 7, 2004 #6
    Thanks, but I would also be interested in where the number comes from and perhaps the function depth(pressure, type of gas, etc.) or a table if anything of the sort is available.
  8. Oct 25, 2004 #7
    Here is a link to an old report on Electron Cyclotron Resonance (ECR) ion sources. These are used to produce high charge state ions for accelerators like cyclotrons or linacs.
    Take a look at Table 1. You can see that they managed to fully ionize Argon, and produced a small current of Ca +19 (all but one electron gone.) I think that newer ECRISes can remove more than half the electrons for a Uranium ion.
    Last edited by a moderator: Apr 21, 2017
  9. Oct 25, 2004 #8
    Thanks everybody.
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