Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Converting 208Pb to 206Pb or 203Tl isotopes

  1. Jan 31, 2007 #1
    Are there any way I can take 208Pb and change it to 207Pb or even 206Pb and the other thing is, can I take Lead Pb I’m not sure what type of lead do you get then buying, maybe 204Pb or something can I take 204Pb and change it to 203Tl?
    This is all by taking some electrons and changes it to something else I’m not 100%, please correct me if I’m wrong.
    And in the process above there will probably be energy generated in heat and I hope not radiation and I want to convert that to electricity because that will be a clever thing to do then to waste to.
  2. jcsd
  3. Jan 31, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No you cannot.

    You are talking about nucleous level interactions, this cannot be done in your garage.
  4. Jan 31, 2007 #3
    Well you have a fact there!
    But I will like to know the process, and it’s possible, it happened then the universe where created, just imagine the big bang if you look at all the water in the ocean and that’s a byproduct from a hydrogen and oxygen explosion.
  5. Jan 31, 2007 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    The elements were formed by nuclear reactions - in stars (and novae and supernovae).

    The chemical compounds came later, but chemistry does not change the elements, but only the combinations of elements.

    To go from Pb208 to Pb207 requires the removal of a neutron. One has to determine the binding energy of that neutron, which is like several MeV. A high energy gamma (photon) could do it, but most natural gammas are less than 2 MeV, and actually, most are less than 1 MeV, IIRC. Otherwise, the Pb nucleus must be struck with a neutron or proton in an inelastic scattering reaction.
  6. Jan 31, 2007 #5
    It would be a lot easier to remove a neutron that adding one, to my understanding, and how can a man kind do that stuff, why must they use U or Pu in a nuclear reaction? Why not something cheaper like copper or lead more common materials.

    How about, use one reaction to fuel another reaction if necessary
  7. Jan 31, 2007 #6
    It is all about fission. Most modern physics texts have a section on nuclear reactions where you can read in detail about it.

    It turns out that when certain very heavy elements are hit with low energy neutrons the go into an excited state for a very small time and then break apart. Now it turns out that the rest mass of the fragments is less than the rest mass of the initial system so the excess energy mainly goes into the kinetic energy of the fission fragments. The fission fragments do not travel very far and lose their kinetic energy to collisions with atoms in the fuel. You can extract this energy as heat which can be used to make electricity.

    The reason we don't use copper or lead is it takes a lot of energy from an inelastic collision to fission these (and other processes are more likely). Thus the output of energy is not favorable.
  8. Jan 31, 2007 #7


    User Avatar
    Science Advisor
    Homework Helper

  9. Jan 31, 2007 #8


    User Avatar
    Staff Emeritus
    Science Advisor

    As Norman mentioned, the process for energy release is fission, and only three isotopes of U and Pu are economically fissionable - U233, U235 and Pu239 - all of which fission with neutrons.

    Neutrons can be produced by the alpha-bombardment of Be-9, and the alpha particles can be obtained from Ra-226, Po-210 or Pu-238, or fast neutrons are obtained by accelerating deuterons into tritons (in a tritiated target) in a so-called neutron 'howitzer'. However, use of such radioactive sources requires a license and strict controls.
  10. Feb 1, 2007 #9
    Like example: If I buy a metal say its lead. How does I know if it’s Pb-206, Pb-207 or Pb-208, lead only have 3 Stable isotopes the rest is half life or unstable

    Pb-206 + 6.8Mev gamma ray > 1neutron + Pb-205
    Neutron stripper, does anyone know how this can be done
    Last edited: Feb 1, 2007
  11. Feb 1, 2007 #10
    According to this page:

    Natural lead is on average a combination of:
    1.4% Pb-204, 24.1% Pb-206, 22.1% Pb-207 and 52.4% Pb-208

    And making a 6.8 MeV photon would require a laser emitting at 183 nm. Which is much shorter wavelength than the popular and easily available helium-neon lasers. I don't know much about lasers, so i don't know if something like this even exists on a commercial level.
  12. Feb 1, 2007 #11
    Pb-204 falls under the Natural radioactive range, so that 1.4% will be radioactive and have a half life of 10,000 years, isn’t that harmful to all living cells?
  13. Feb 4, 2007 #12
    According to that table the Pb-204 has a half life of greater than 1.4E+17 years (that is a really, really long time. Where did you get your 1e4 years?). And it is an alpha emitter and will not penetrate the skin, in fact a simple sheet of paper will stop alphas.

    See this page on the penetration of alphas, betas and gamma radiation:
    http://www.fas.harvard.edu/~scidemos/QuantumRelativity/PenetrationandShielding/PenetrationandShielding.html" [Broken]

    Last edited by a moderator: May 2, 2017
  14. Feb 4, 2007 #13


    User Avatar
    Staff Emeritus
    Science Advisor

    Any heavy metal is toxic. As, Sb, and Hg, Tl, Pb, . . . . are all toxic particularly to nerve cells.

    I have an older friend who has had nerve damage due to As and Pb poisoning. His memory has started to fail. It is very sad to see this, and there doesn't seem to be much in the way of treatment or recovery.
  15. Feb 4, 2007 #14
    Under Wiki man, its not actually 1e4 like I’ve made you understand, it’s “>1e4”
    1e4 are the highest Wiki goes, but still it’s longer that I’ll ever will life

    EDIT: “The alpha particle mass is 6.644656×10-27 kg, which is equivalent to the energy of 3.72738 GeV.”
    If Pb-204 is an alpha emitter can’t I nick that radiation and generate electricity out of them, please?

    How can I avoid Pb poisoning?
    Last edited: Feb 4, 2007
  16. Feb 4, 2007 #15


    User Avatar
    Staff Emeritus
    Science Advisor

    No - it is not practical since the decay rate is so low and separating the alpha particles and electrons is rather impractical. If it was practical, people would be already doing it.

    Pb-204 is considered stable. Looking at the wikipedia article, the table does indicate a half-life of >1.4×1017 y, which is effectively stable. I

    Avoid contact or ingestion of lead. In handling heavy metals, one should wear appropriate hand protection - gloves. If hands come in contact with lead, then wash them. If lead is ingested, then one must ingest chelating agents to help remove the lead.

    If one melts, or especially boils lead, do not breath the vapors. Heated lead should be handled in glove box or ventilated hood with filter to capture lead-bearing particulates.
  17. Feb 5, 2007 #16
    Hmm ok so you say the decay rate is to slow to use them, but do you know of any practical way for me to test it and see how many energy I can get out Pb-204, I’ve also seen on TV that some rocks or floor tiles can be mistakenly pick out for detection for uranium //radiation materials, can that radiation “floor tiles” been used for the purpose to generate electricity, and just for interest sake, what device will I need to build to covert the alpha particles to electricity?
  18. Feb 5, 2007 #17
    You can't convert it into electricity! If you had a radioactive source powerful enough to generate usable energy you'd probably be arrested by Homeland Security for having nuclear material in your possession!

    If it was possible to generate useful amounts of energy from a standard lump of lead, we'd already have it as a power source. Rather than filling your car with 10 gallons of petrol, you'd just put a kilo of lead in there. But that isn't happening because you can't get usesul energy from it.

    You don't seem to be appreciating the fact that if it was as simple as that, someone would have done it already! People who work in the nuclear physics industry are paid to come up with such ideas.
  19. Feb 5, 2007 #18


    User Avatar
    Staff Emeritus
    Science Advisor

    With a half-life on the order of 1017 years - Pb-204 is effectively not radioactive, but for all intents and purposes, it is inert/stable.

    Pu-238, a very strong alpha-emitter, is used in radioisotopic thermal generators (RTGs). The heat generated by alpha and subsequent gamma decay is used to produce electricity via thermoelectric systems. They do not bother to collect alpha particles - its just too impractical.
  20. Feb 5, 2007 #19
    So how do the rays heat up the water, is it like a microwave you just put in the water and then it’s heat up, after you press the on button, but does α, β, γ rays make everything heat up then exposed to?

    The only way I know about using thermoelectric @ high efficiency are a turbine to make electricity form heated steam/water

    Are there any other ways of making electricity from heat only? Because I don’t know of everything else than a turbine?
    Last edited: Feb 5, 2007
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook