Tritium Key Chain Radiation Survey - Dangerous or Not?


Brought a calibrated radiation survey meter home from work (Thanks GE Healthcare) to perform a measurement on the amount of gamma radiation (x-rays) given off by a Tritium keychain I bough off of eBay. These key chains have a glass vial in them filled with Tritium (Hydrogen 3) gas, and the surface coated in Phosphor. Tritium decays with a 7keV x-ray that excites the Phosphor and makes it glow.

A lot of people argue that the glass absorbs all the radiation due to the low energy, but I have found that to be not completely true.

Note: The brand of this keychain is "Codegeek" - Titanium Marker
At a distance of ~1 inch, I measured ~0.05 mRem/h.
That number goes up a lot if you set the detector directly on the keychain.

After seeing these numbers I took the unit off my keychain. While they are safe to play with, and to use in general, I found whenever I am driving the unit basically touches my knee. I was concerned about the elevated exposure over 100's or 1000's of hours of sitting in my car.

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