Are the daughter particles Ionized when the parent particle beta decays?

  • #1
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Summary:
I was wondering if the resulting daughter element is ionized after the parent undergoes beta(or any other kind) of radioactive decay,
I was wondering if the resulting daughter element is ionized after the parent undergoes beta(or any other kind) of radioactive decay,
 

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  • #2
mathman
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Daughter particles (charges) such as alpha (He4 nucleus) or beta (electrons or positrons) are ions. However there are enough other things around to quickly neutralize.
 
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  • #3
Astronuc
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Summary:: I was wondering if the resulting daughter element is ionized after the parent undergoes beta(or any other kind) of radioactive decay,

I was wondering if the resulting daughter element is ionized after the parent undergoes beta(or any other kind) of radioactive decay,
Very briefly (less than an nanosecond (10-9 s), and probably on the order of 10-11 s). [I'll try to find an open source reference] Note that a beta particle is an electron and it will have a short range in the matter. It may collide with other electrons in the original atom, but it will interact with other electrons in neighboring atoms. The range in the material depends on the energy of the beta particle and type of material (electron density and binding energies of the atomic electrons). A positive ion will 'steal' an electron from a neighboring atom, which sets off a cascade of electrons jumping from other atoms until the original beta electron finds an ion and recombines.

When a positron (sometimes called a positive beta particle) is emitted, the atomic charge goes from Z to Z-1 and an atomic electron is emitted. The positron slows down through collisions until it combines with a negative electron and the pair annihilates into two photons of ~0.511 MeV. That is the basis of a PET scan. The atom that loses an electron then steals an electron from one of its neighbors and that starts a cascade of electron stealing until atom absorbs the free electron from the atom that emitted the positron.

In the case of the alpha particle, the atom number decreases by 2, i.e., Z -> Z-2, and so two electrons are lost. The alpha particle will slow down in the vicinity of the atom from which it came and become a helium atom, while the emitting atom will lose two electrons. Those free electrons will migrate to an available ion and recombine.
 
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  • #4
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It should be legal to produce a neutral atom by beta decay, but with a tiny branching fraction.
For the energy has to go somewhere. Consider the lowest energy of all beta decays... Re-187 to Os-187. 2600 eV minus the antineutrino share. The ionization energy of Os is 8,7 eV. What is the branching factor of the following reactions:
  1. Re-187 to any bound state of Os-187 and all the rest of energy to antineutrino?
  2. Re-187 to any bound state of Os-187 and the rest split between a continuum spectrum photon and continuum spectrum antineutrino?
Also, would the photon in this case be far UV or soft X-ray?
 
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  • #5
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Found an example. For a free neutron (decay energy 782 keV, total ionization energy 13,6 eV) the branching fraction for two body beta decay (only antineutrino emitted) is quoted as 4 per million. Not specified is the fraction for emitting antineutrino and photon, which also leaves a neutral atom.
Tritium has just 18 keV total decay energy and 24 eV ionization energy of He. What is the branching fraction for tritium decay into neutral He atom (with only antineutrino or also photon)?
 
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  • #7
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Daughter particles (charges) such as alpha (He4 nucleus) or beta (electrons or positrons) are ions. However there are enough other things around to quickly neutralize.
Thank you so much!
 
  • #8
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Daughter particles (charges) such as alpha (He4 nucleus) or beta (electrons or positrons) are ions. However there are enough other things around to quickly neutralize.
Thanks!
 
  • #9
181
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Very briefly (less than an nanosecond (10-9 s), and probably on the order of 10-11 s). [I'll try to find an open source reference] Note that a beta particle is an electron and it will have a short range in the matter. It may collide with other electrons in the original atom, but it will interact with other electrons in neighboring atoms. The range in the material depends on the energy of the beta particle and type of material (electron density and binding energies of the atomic electrons). A positive ion will 'steal' an electron from a neighboring atom, which sets off a cascade of electrons jumping from other atoms until the original beta electron finds an ion and recombines.

When a positron (sometimes called a positive beta particle) is emitted, the atomic charge goes from Z to Z-1 and an atomic electron is emitted. The positron slows down through collisions until it combines with a negative electron and the pair annihilates into two photons of ~0.511 MeV. That is the basis of a PET scan. The atom that loses an electron then steals an electron from one of its neighbors and that starts a cascade of electron stealing until atom absorbs the free electron from the atom that emitted the positron.

In the case of the alpha particle, the atom number decreases by 2, i.e., Z -> Z-2, and so two electrons are lost. The alpha particle will slow down in the vicinity of the atom from which it came and become a helium atom, while the emitting atom will lose two electrons. Those free electrons will migrate to an available ion and recombine.
Wow! Thanks for the reply!
 
  • #10
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Daughter particles (charges) such as alpha (He4 nucleus) or beta (electrons or positrons) are ions. However there are enough other things around to quickly neutralize.
Thank you!
 

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