0
$\begingroup$

Since beta-particles are just free-moving electrons, shouldn't they be caught by strongly-electronegative atoms and thus create anions? Why do they instead create more cations by knocking other electrons out of their orbits? Does it, perhaps, depend on the speed of electron: i.e., slow-moving, non-ionizing electrons are more likely to be caught by atoms?

$\endgroup$
0
$\begingroup$

Beta particle energies are of order $10^5$ eV, which is vastly greater than typical electron affinities of order $1$ eV. The beta electron is not going to end up bound to another atom until it's had a chance to dissipate the unwanted $99,999$ eV. The energy is typically dissipated by colliding with other atoms and ionising them.

$\endgroup$
  • $\begingroup$ Thanks. So basically, all beta particles will end up being caught by atoms, but not before they dissipate their energy? Also, am I right to understand that secondary electrons can be caught immediately because they are slow? $\endgroup$ – A.V. Arno Aug 10 '18 at 17:18
  • 1
    $\begingroup$ Secondary electrons will have a large range of energies because their energy depends on whether the beta particle scored a full hit or just a glancing blow. Some will have low enough energies to be captured immediately while others will have much higher energies. $\endgroup$ – John Rennie Aug 10 '18 at 17:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.