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I Beta decay and plexiglass

  1. Dec 1, 2016 #1
    Hi, I recently bought a glow-in-the-dark key chain, similar to http://tinyurl.com/zqf5sxb (image link). It is made from solid plexiglass, with a hollow cylinder in the middle, containing tritium. The electrons from the beta decay presumably hit a fluorescent wall on the inside of the cylinder, making the thing glow. Really cool!

    My question is: should I worry about beta decay happening inside 3-6 mm of plexiglass?
  2. jcsd
  3. Dec 1, 2016 #2


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    It is fully contained even by the first 0.1 millimeters. Tritium decays are very low-energetic.

    If any relevant radiation could get out, they couldn't sell those key chains.
  4. Dec 1, 2016 #3
    Thank you! I just wanted to be responsible and check it out. And now I am part of this awesome forum! =D
  5. Dec 1, 2016 #4


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    Just be aware that it will glow about half as much in 12 years ... :rolleyes:
  6. Dec 1, 2016 #5
    Yep, I want to track it over the years. Maybe I should buy one every 12 years for fun. Adding it to my calendar now ;)
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