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  1. Phillip
    June 27, 2012 • 8:51 am

    If radium decays by alpha emission, then surely the exposure is minimised by the glass/crystal face of the watch, or the metal backplate, which the alpha wouldn’t penetrate. Presumably, the exposure risk is from beta decay of Pb-214 (product of 2 further alpha decays from Rn-222 via Po-214) and then beta from Bi-214, or a small amount of associated gamma radiation. Given the length of the half-lives of these isotopes and the relatively small amount of Ra, what is the realistic exposure rate from wearing a radium-painted watch? Having never held a scintillator up to one, I don’t know how much detectable radiation would be coming out of one – is it significant compared to background radiation or a meaningful dose, or is the risk mainly to do with concentration on a single patch of skin as you generally wear a watch in the same place all the time…

  2. Sarah Everts
    June 27, 2012 • 2:25 pm

    Hey Phillip, Yes indeed… as I understand it, beta decay is more problematic. I think the concern for wearing the watch is the extended exposure time in a small area. Green said that some of the radium watches really get the Geiger counter ticking, others less so. I really wouldn’t wear one if I hadn’t checked it with a scintillator first and then figured out my annual exposure… And actually I’d hesitate to keep a watch around the house without checking: (Full disclosure: I’m a worrier.) I do think most are probably pretty safe, but in the rare case that it *was* pretty hot, I’d hate to expose friends or family unwittingly.
    All that being said, I’m still in the market for a radium Jesus. I just pray he’s not too hot.

    • Pat
      December 20, 2013 • 2:46 am

      I have a Virgin Mary uranium statue from 1939. Are they really that hard to find?

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