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Before you head over to eBay: many of these have radium dots that can be detected by gamma ray detectors at customs offices. The paint may not light up anymore,

by Luc 8y ago

Before you head over to eBay: many of these have radium dots that can be detected by gamma ray detectors at customs offices. The paint may not light up anymore, but the radium is still emitting nearly as strongly as when originally made (half-life 1600 years).

deleted 8y ago
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tzs 8y ago
Is there a reasonable way to tell if an old glow in the dark thing uses radium (or some other radioactivity based lighting mechanism) rather than simple phosphorescence, short of finding a Geiger counter? I've got a Westclox Baby Ben glow in the dark wind-up alarm clock that I've had at least 50 years [1]. I don't think that there is anything I have owned longer. It still works fine, although sometimes it needs to be slapped a little to get it going if it hasn't been used for several years. I still use it as a backup whenever I need an alarm in circumstance where an alarm failure would lead to serious, hard to deal with consequences. Westclox definitely used radium at one time in their Baby Ben clocks [2], but from what I read they stopped in the early to mid '60s. Mine was bought around the mid '60. Mine only glows after exposure to bright light, suggesting it is using phosphorescence rather than radioluminescence, and so should be safe, but it would be nice to check. Would a homemade cloud chamber [3] work? [1] https://imgur.com/4CljfDL https://imgur.com/4CljfDL [2] https://www.youtube.com/watch?v=wp6Ddcc4GAg https://www.youtube.com/watch?v=wp6Ddcc4GAg [3] https://www.sciencefriday.com/educational-resources/build-a-cloud-chamber/ https://www.sciencefriday.com/educational-resources/build-a-...
- helper 8y ago
  If it only glows after exposure to light it isn't radium. CMOS sensors can detect gamma particles. If you have an android phone there's an app that actually works (assuming you follow the calibration steps properly)[1]. Apparently Radium mostly emits alpha particles so I'm not sure how effective this would be. If you are thinking about buying an actual geiger counter make sure to get one with a working probe assembly. A lot of surplus geiger counters are sold without the probe assembly with is the expensive part and the thing that wears out[2]. The probe assembly also needs to be properly calibrated. [1]: https://play.google.com/store/apps/details?id=com.rdklein.radioactivity https://play.google.com/store/apps/details?id=com.rdklein.ra... [2]: https://www.amazon.com/Atomic-Adventures-Islands-Forgotten-Isotopic/dp/1681774216 https://www.amazon.com/Atomic-Adventures-Islands-Forgotten-I...
SamReidHughes 8y ago
Also beware that radium decays to radon. Some watch collectors have to worry about this.

by Luc 8y ago

deleted 8y ago

[deleted]

tzs 8y ago

Is there a reasonable way to tell if an old glow in the dark thing uses radium (or some other radioactivity based lighting mechanism) rather than simple phosphorescence, short of finding a Geiger counter? I've got a Westclox Baby Ben glow in the dark wind-up alarm clock that I've had at least 50 years [1]. I don't think that there is anything I have owned longer. It still works fine, although sometimes it needs to be slapped a little to get it going if it hasn't been used for several years. I still use it as a backup whenever I need an alarm in circumstance where an alarm failure would lead to serious, hard to deal with consequences. Westclox definitely used radium at one time in their Baby Ben clocks [2], but from what I read they stopped in the early to mid '60s. Mine was bought around the mid '60. Mine only glows after exposure to bright light, suggesting it is using phosphorescence rather than radioluminescence, and so should be safe, but it would be nice to check. Would a homemade cloud chamber [3] work? [1] https://imgur.com/4CljfDL https://imgur.com/4CljfDL [2] https://www.youtube.com/watch?v=wp6Ddcc4GAg https://www.youtube.com/watch?v=wp6Ddcc4GAg [3] https://www.sciencefriday.com/educational-resources/build-a-cloud-chamber/ https://www.sciencefriday.com/educational-resources/build-a-...

helper 8y ago
If it only glows after exposure to light it isn't radium. CMOS sensors can detect gamma particles. If you have an android phone there's an app that actually works (assuming you follow the calibration steps properly)[1]. Apparently Radium mostly emits alpha particles so I'm not sure how effective this would be. If you are thinking about buying an actual geiger counter make sure to get one with a working probe assembly. A lot of surplus geiger counters are sold without the probe assembly with is the expensive part and the thing that wears out[2]. The probe assembly also needs to be properly calibrated. [1]: https://play.google.com/store/apps/details?id=com.rdklein.radioactivity https://play.google.com/store/apps/details?id=com.rdklein.ra... [2]: https://www.amazon.com/Atomic-Adventures-Islands-Forgotten-Isotopic/dp/1681774216 https://www.amazon.com/Atomic-Adventures-Islands-Forgotten-I...

SamReidHughes 8y ago

Also beware that radium decays to radon. Some watch collectors have to worry about this.