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I want to build a Betavoltaic Battery

  1. May 9, 2010 #1
    I want to build a "Betavoltaic Battery"

    A while ago I got a tritium keychain that will glow for 10 years, and since then I've gotten very interested in building a generator based on this. Originally I wanted to build a conventional RTG but apparently it is hard to find radioactive materials that are warm to the touch :/

    Anyway I thought this would be the place to come for some input on whether or not this would work. My plan is to use Americium sources from smoke detectors because they are easy to find. Obviously a high-beta source would be better but I don't know where to buy something like Stronium 90. The Americium would be suspended in a vial of water mixed with a readily available phosphor (possibly zinc sulphate?) which would then glow, if the stars lined up. The glowing vile would be surrounded by a small solar panel from eBay, and hopefully produce enough power for a digital watch.

    There are three things I'm not sure about: would Americium cause zinc sulphate to glow, would the wavelength of zinc sulphate power a solar cell, and would the gentle glow be enough to produce any measurable power? Also my budget is $50 :)
  2. jcsd
  3. Jun 25, 2010 #2
    Re: I want to build a "Betavoltaic Battery"


    do you mean zinc suphide? not sulphate?

    ok ill answer those three questions,

    yes, if you are referring to zinc sulphide, it would work because ive done it myself.
    i think so, but im not sure.
    i dont think the glow would generate any useful power and i think it would be barely visible,
    i put an am. 241 smoke alarm source next to a sheet of zns (zink sulphide) and i had to sit in a dark room for a while before i could see the glow, i think a budget of $50 is a bit low,
    i think a budget of $250 would be better

    i really like your idea though, i wish you success in building that :)

    thanks :)
  4. Jun 25, 2010 #3


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    Re: I want to build a "Betavoltaic Battery"

    Am241 smoke detector sources are quite weak -- consider the long half-life, for one. And they're not a very good photon source, which are the only things that matter for you here.

    I can think of sources that would work better, but I'm not sure what regulations there are on their use outside of research.

    Possibly strontium aluminate would be better than zinc sulfide, but I'm not sure that's within your budget.
  5. Jun 25, 2010 #4
    Re: I want to build a "Betavoltaic Battery"

    By the way, what happens to the power excess of a betavoltaic cell when it is not connected? Does it turn into heat?

    I can imagine that an electrode gets saturated with negative potential and pushes new electrons back inside to the nucleus. Can strong negative potential prevent beta decay or put it in equilibrium? Perhaps not, since neutrinos are involved.
  6. Jul 2, 2010 #5
    Re: I want to build a "Betavoltaic Battery"

    Hasn't it occurred to anyone that radioactivity is quite nasty to have around.
    Americium sources are tolerated because they are small, weak and the dangers of fire are more pressing.

    If you collect enough to represent appreciable power, you have enough to be a serious health hazard.
  7. Jul 2, 2010 #6
    Re: I want to build a "Betavoltaic Battery"

    loooooser! just shield it in lead, simples !
  8. Jul 2, 2010 #7
    Re: I want to build a "Betavoltaic Battery"

    The harmfulness of radioactivity is overhyped. Single thunder gives you more X-ray radiation than all radioactive materials people have ever dug.
  9. Jul 2, 2010 #8
    Re: I want to build a "Betavoltaic Battery"

    :rolleyes: You want a Darwin Award? go right ahead.
  10. Jul 2, 2010 #9
    Re: I want to build a "Betavoltaic Battery"

    Take aluminum, and Iron oxide, mix by weight 3 parts Alum to 8 parts IO.
    1. insert magnesium fuse
    2. light magnesium fuse
    3. run
    4. go to store
    5. buy a digital watch for $19
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