A very interesting read, indeed. I do see a "T" above the "Swiss" on the 12 hour subdial of my 2446C GMT so that should indicate the dial uses tritium. My radiation detector (old school Civil Defense Victoreen branded unit) does not register any gamma or beta radiation on the dial of my watch but it sure does perk up when I open the shield and press it against the open hands of my Jefferson Golden Hour clock in my bedroom! Yikes!

Steve

: This article on the Horological Meandering discussion forum is
: excellent -- Watches and Radiation Risk . You might want to
: read the posting if you own old watches with radium dials and
: hands (and even bezels).

: Here are the author's recommendations: I think there are clear
: and identifiable risks associated with wearing a vintage watch
: with Radium-226. Those risks vary, but in certain circumstances
: are very high. Collectors should appreciate that a Radium-226
: dial poses a real health risk not only to the wearer but also to
: those in regular close proximity to the wearer. That risk will
: vary depending on a number of factors and I would put forward
: the following checklist; A simple Geiger counter can be
: purchased at a reasonably low price. This will enable a quick
: test to evaluate how much Gamma radiation is evident in a watch.
: Generally speaking, watches with radioactive lume manufactured
: between the 1920s and the 1960s will, typically, have had
: Radium-226 applied. That is a decent working assumption. Some
: will have different isotopes with much shorter half-lives. For
: Radium-226, however, expect the Geiger counter to light up. If a
: watch is identified with Gamma radiation, evaluate at what point
: you feel comfortable with the risks. Clearly, a watch that emits
: over 10 uSv per hour is one that I would simply not want to
: wear. It would be the equivalent of having 1-2 chest X-rays
: every single day. One that emitted at 1 uSv per hour might be
: something I would wear intermittently. Everyone will have their
: respective tolerance levels. uSv 100/hour? I actually wouldn't
: want to be next to someone with such a watch. With Radium-226,
: be aware that it carries a much greater risk to health if the
: watch is worn overnight courtesy of the Radon gas emission as
: well as the higher vulnerability of the head to Gamma. Radiation
: dust that will exist on the dial is toxic. Never open a watch. I
: think this rule needs to be quite categorical. Radon testing
: kits are very cheap and easy to use. For collectors that have
: Radium-226 watches, especially those with large collections
: concentrated in the same place, it would be a great idea to test
: for Radon. One quick take-away for the Heuer enthusiasts --
: remember to put your early Autavia on the nightstand before
: bedtime, or even better, leave it in another room.

: Jeff

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