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Internal Conversion of Bi-207/Pb-207

  1. Oct 23, 2011 #1

    I am aware that due to the three body kinematics of beta decay, the energy spectrum of the electrons emitted is a continuous spectrum (where at one extreme the electron gets all of the disintegration energy and the antineutrino none, and the converse at the other extreme)
    I am doing an experiment at university to measure the electron energy spectrum of Bi-207, and there are a number of spikes in electron spectrum
    How is it that Bi-207 can generate electrons of well-defined energy? Bi-207 decays by electron capture to Pb-207, so I guess this isn't really a beta decay question at all.

    I know the answer to the question involves internal electron conversion. But which element undergoes internal conversion? Is the Pb-207 nuclei created in an excited state and it becomes stable by emitting electrons of distinct energies through internal conversion?
    Thanks :)
  2. jcsd
  3. Oct 23, 2011 #2


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    Science Advisor

    Sounds like you've got it identified correctly. Bi-207 decays to Pb-207 through electron capture. Pb-207 is left in an excited state and subsequently decays either through gamma ray emission or internal conversion, producing electrons of well-defined energies corresponding to the energy levels of Pb-207.
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