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  1. BatDad

    BatDad May 23, 2020 9:04am

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    Do Tritium hands have a half life for luminosity?

    What I mean is if a batch of base material is split into two, one made and applied to a set of hands. N years pass, and the second batch is made and applied to a set of hands. Is it conceivable that the batches would glow the same color, but have differing decay rates when compared to each other. But age out their luminosity relatively at the same pace.

    Edit - related thread https://omegaforums.net/threads/vintage-speedy-tritium-glow.42816/#post-504744
     
  2. Mouse_at_Large

    Mouse_at_Large still immune to Speedmaster attraction May 23, 2020 9:16am

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    The luminosity is due to the to the reaction between radiation from the tritium reacting with a phosphorescent material. Hence the intensity of the luminosity is a product of both materials and their decay rates.
     
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  3. BatDad

    BatDad May 23, 2020 9:37am

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    So if you see folks selling tritium material - it’s inherently emitting radiation at that point?

    There isn’t a mixing process that starts a chemical reaction? And by extension, it won’t matter when it was applied to a set of hands?

    I suppose a follow on question - how is tritium manufactured - or is it mined and processed?
     
  4. Uscjake87

    Uscjake87 May 23, 2020 10:29am

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  5. TDBK

    TDBK May 23, 2020 10:40am

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    Tritium is just hydrogen. You may remember from school that an atom has a nucleus (where the heavy positive protons and neutral neutrons live) and a number of negative electrons orbiting it. An atom's chemical behavior comes from the number of electrons it has, which is by default the same as the number protons in the nucleus (balancing the positive and negative charges).

    Your basic generic hydrogen atom has just a proton and an electron, no neutrons. But the nucleus can accommodate one or two neutrons alongside the proton... for a while, anyway. The resulting atoms are heavier but otherwise chemically the same as basic hydrogen (they each have a single electron). With one neutron is called "deuterium", with two, is called "tritium" (because the atoms are roughly twice as heavy and three times as heavy as entry-model hydrogen, respectively).

    So one or two neutrons can barge into the proton's one-bedroom nucleus and crash on its couch. And with just one extra, it's stable: deuterium will happily remain that way indefinitely (and about one hydrogen atom in 6420 is deuterium: your body is about 1/10 hydrogen, so if you weigh 50 kilos, it's about 16 grams deuterium). But there is a crowd, so two neutrons on the couch is too much, and sooner or later they have to go: it's entirely random when it happens, but if you have a bunch of tritium atoms and put them in a storage locker, when you come back to clear it out 12.3 years later, half of them will have decayed (they turn into helium, which sort of breaks the couch-surfing metaphor, but there you go).

    Tritium is useful in watches because that constant rate of decay can be harnessed, with a little phosphor, into a continuous glow which requires no external charging or power source. It does wear out, both because the tritium inherently gets used up by half every 12.3 years, but also because (if I understand correctly) the decay products degrade the chemical lume.

    Tritium is not particularly dangerous, much less so than radium, which has also been used for watches. It's probably not a good idea to inhale it or drink water which has tritium in it. It occurs rarely in nature (sometimes when hydrogen in the atmosphere gets slammed with a cosmic ray particle, you get tritium). It's manufactured by using a nuclear reactor to irradiate lithium, breaking those happy nuclei into doomed tritium households. It's controlled because it's a component of thermonuclear weapon designs.
     
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  6. killer67

    killer67 May 23, 2020 2:14pm

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    Got a D in Chemistry but this post above was a refresher showing why that grade might have been too generous. I did understand that I mustn’t drink tritium water
     
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  7. BatDad

    BatDad May 23, 2020 7:17pm

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    Hah - I’m very similar. Last time I took Chemistry was when I was 16, and that seems a long long time ago.

    The response is great and if Ive understood correctly does seem to back up one of my original questions - batches of tritium will exhibit the same half life characteristics
     
  8. Dan S

    Dan S May 23, 2020 7:33pm

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    When you say "and the second batch is made", I am assuming by "made" you simply mean mixed with liquid so that it can be applied, but that the two batches are otherwise exactly the same. In other words, the "base material" includes both the tritiated compound and the phosphor.

    If so, then the two batches of lume described in your thought experiment would have the same characteristics since the material including the tritium would have the same isotopic composition initially, and would evolve the same way over time.
     
    Edited May 23, 2020 7:38pm
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  9. BatDad

    BatDad May 23, 2020 7:57pm

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    I’m really just exposing my complete lack of knowledge on the preparation, mixing and application of luminous material. :)

    I had made some assumptions along the way - firstly there’s some sort of powder - that’s prepared (with liquid as you mention above) and then applied to the hands.

    The fundamental question (as I think I’m learning more) - can you(someone; not me) store a key portion of tritium, mix it with phosphor, and water and apply to hands over a differing timeline - but create a ‘like new’ tritium hand quality observed under UV light that is consistent with the appearance of ‘vintage’ hands.

    I think I’m learning - no. It’s all down to when the tritium ‘mix’ is prepared
     
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  10. Dan S

    Dan S May 23, 2020 8:20pm

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    A luminous compound will have an inorganic phosphor, pigment, a polymer binder, and maybe other minor ingredients (e.g. antimicrobials). Obviously this is mixed with a solvent to make it into a "paint". My understanding, is that tritium is generally incorporated into the luminous material as a tritiated polymer binder component. In other words, in synthesizing one or more of the polymers used in the binder, a significant number of the "normal" hydrogen-1 atoms in the polymer are replaced by tritium (hydrogen-3) atoms (it's not actually done that way, but that's the end result). So tritium is not present in painted-on lume in the form of tritium gas, but as hydrogen-3 atoms chemically bonded to other atoms in the polymer (e.g. carbon atoms). Hydrogen-3 atoms would normally be almost completely absent in polymers, because the natural abundance of tritium is incredibly small. At the time the binder is prepared, it is enriched in tritium to the desired degree, and the tritium is then gradually lost over time (half lost after 12 years or so).
     
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  11. bigsom

    bigsom May 23, 2020 9:31pm

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    To do what you are proposing requires measurable tritium activity, meaning you would have to buy some activity of tritium as a waste product from a nuclear reactor. Tritium is most commonly made by neutron bombardment of water in a nuclear reactor as fission occurs.

    I guess you could also harvest tritium gas from tritium tubes in newer commercial watches.

    Then you would have to use that tritium in the synthesis of a bonding hydrocarbon (I think Dan's explanation of where the hydrocarbons are used in tritium luminescent material is correct). Then if you applied or created an admixture with old luminous material, I think you could reactivate old luminous material the way it was when it was new.

    It would require you know how to do the synthesis of the bonding material with good yields and that it would also mix well with the old material you want to activate.

    Edit - also you would do this all in a hot cell and be a radiochemist etc etc
     
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  12. timecube

    timecube May 24, 2020 2:27am

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    For the most part, yes. However there are a few notable exceptions; and deuterium is one of those isotopes which is enough different from its more common form (due to mass) to exhibit differences in chemistry. For example, heavy water is mildly toxic to multicellular life (but not bacteria). Tritiated water hasn't been studied as extensively, but it would be expected to have further (minor) differences from 1H2 16O.