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B Risk of tritium (sight) from 1970-1990.

  1. Sep 9, 2017 #1
    Good morning everyone,

    First of all I have to say that I didn't know where to ask this question, but I am sure people with knowledge in nuclear physhics is who I will trust, and not optics amateurs, at least with something potentially dangerous.

    I got an optics device that has an orange stick of around 20x15mm, with the label "T 0.5Ci" with the radioactivity symbol. I have been studying and it is a ZRAK sight built around 1970-1990 in USSR/Yugoslavia, probably used in some european war. Also, I have read that the radioactive material used to be tritium.

    Am I in danger by preserving this device? How dangerous is the tritium? Is it possible to be radiating us by just touching the sight or being really close to it? Does this radiation "infect" other materials (like the metal cover) and then those materials "infect" us? In case is dangerous, am I safe if I hide it in a box and cover it with some lead sheet (not hermetic) to avoid it "infects" other objects and tools in the room?
    - I would preserve and use this sight just if I am not on risk. Radioactivity scares me.

    Sorry for my ignorance. I have no idea about the behaviour of the tritium or radioactive materials.

    Also, I give an image from some sight to show how is the metal cover and the symbol, although the image that I attach has another label. Mine is "T 0.5Ci".

  2. jcsd
  3. Sep 9, 2017 #2


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    Staff: Mentor

    Tritium undergoes beta decays with a very low energy. It is easily shielded by the container. The decays can be used to produce a bit of light, often used for the hands of clocks or glowing keychain items, for example, and you can freely buy these items. As long as the container is closed, there is absolutely no radiation outside.

    If the container with the radioactive label is damaged, bring it to an expert.
    No. It is only the tritium that is radioactive. Radioactive things don't make anything else radioactive*.

    Tritium has a half-life of 12.3 years. If it was built in 1990, only 21% of the initial tritium is left. If it was built in 1970, only 7% are left. 0.5 Ci (=18.5 GBq, different name for the same thing) was the initial activity, it is now much lower.

    *there are a few exceptions, but they are only relevant inside nuclear reactors and nuclear weapons.
  4. Sep 9, 2017 #3
    Thank you very much.

    Ok, last question: just in case the shield is a little bit broken but from inner parts and I cannot see it from outside (imagine spaces in screws/nuts, or between parts of the sight). Can I afford any "cheap" solution of "radioactivity/tritium radioactivity detector" to check just really close to the sight if is any exposure? I read about some "phone apps" that through the camera (gamma rays) could detect it (I was skeptic, but you are the expert). That would be cheap for sure.

    Although with your answer and I am cool, as you saw me no danger at all, it is just in case I would like to test it.
  5. Sep 9, 2017 #4


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    Staff: Mentor

    The part with the sticker is not the container containing the tritium.

    Typical radiation detectors won't measure anything, for the same reason a closed container is safe: The electrons emitted by tritium are very low-energetic and easily shielded.
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