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Factors which influence to half-life speed

  1. Nov 23, 2014 #1
    Looking for researches, articles and experimental values conserning factors which influence to half-life speed for different isotopes.
     
  2. jcsd
  3. Nov 23, 2014 #2

    mathman

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  4. Nov 23, 2014 #3

    e.bar.goum

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    In general, the halflife of an isotope is considered to be constant, providing physics doesn't change over time. ;)

    The exception is decay via electron capture. That is changed by the amount of electrons in the vicinity of the decaying nucleus e.g. the charge state of the atom. For example, the half-life of completely ionized 7Be is infinite, as the only possible decay channel is EC. For most isotopes that decay via EC, it is only one of the possible decay channels.
     
  5. Nov 24, 2014 #4
    Until recently it was considered that, for example NaCl as an stable compounds is only possible.

    Most of ordinary sources are in the scope. But it's not enough for our "data science" project. The idea is to build some hierarchy of conditions and measurement approach classes, then upload data with indication of accuracy class and test our data analysis model.

    So we need really huge amount of data, not just consideration.
     
  6. Nov 24, 2014 #5
  7. Nov 24, 2014 #6

    e.bar.goum

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    What has this got to do with nuclear physics? or half life?

    What does this have to do with half-life?

    Perhaps you need to reframe the question.
     
  8. Nov 24, 2014 #7
    Ok. Can you give me the link to the researches (where described approaches and methods) and experimental data which prove all this values of half-life mentioned here: http://en.wikipedia.org/wiki/Radionuclide
     
  9. Nov 24, 2014 #8

    e.bar.goum

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    Sure!

    The National Nuclear Data Center is home to most of the collated knowledge of nuclear physics. It is home to the consensus values of half-lifes in the community. Now, if you want to go look at the half life of a particular nucleus, and see the original study, you want to go to the ENSDF database http://www.nndc.bnl.gov/ensdf/ and search for the isotope of interest. The ENDSF file will include the references to the experimental data. For example, I pick 14C, and get this page by selecting the adopted levels, gammas page (but you may also pick reaction by reaction if you choose) http://www.nndc.bnl.gov/useroutput/AR_B3250B5CB2E46AC0B6E43179706C2AB0_1.html

    This tells me that the half life is 5700 years, and that this is found from:

    And I could go look at those papers now, and see the experimental methods used.

    Hope this helps!
     
    Last edited by a moderator: May 7, 2017
  10. Nov 24, 2014 #9
    Great! Thanks a lot!
     
  11. Nov 24, 2014 #10
    Going to add some related links in this tread:
    1. Evidence for Correlations Between Nuclear Decay Rates and Earth-Sun Distance
    http://arxiv.org/PS_cache/arxiv/pdf/0808/0808.3283v1.pdf
    2. Evidence against correlations between nuclear decay rates and Earth–Sun distance
    http://donuts.berkeley.edu/papers/EarthSun.pdf
    3. Experiments on the Effect of Atomic Electrons on the Decay Constant of Be7 II.
    https://publications.lbl.gov/islandora/object/ir:147066
    4.PERTURBATION OF NUCLEAR DECAY RATES
    http://www.whoi.edu/cms/files/1972AnRevNucSci22p165_68424.pdf [Broken]
     
    Last edited by a moderator: May 7, 2017
  12. Nov 24, 2014 #11
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