- #1
ChumpusRex
- 8
- 0
A while ago I bought some novelty keyrings which contained tritium powered lamps.
The marketing information mentioned that the beta particles would be contained by the acrylic shell of the keyring. A not unreasonable claim given the low energy of the tritium beta emission, and lack of associated gamma.
The keyring itself consists of a thin tritium filled glass rod about 25 mm long, and 1-2 mm in diameter. This is embedded in an acrylic cylinder about 8 mm in diameter.
Out of curiosity, I tested one of these keyrings with a GM counter and was somewhat surprised to find it recorded about 100 c/s above background. Presumably this is due to bremsstrahlung generation in the acrylic.
I'm wondering whether this sort of activity is typical of such a device. I was under them impression that the acrylic was a poor generator of bremsstrahlung, so didn't really readily detectable emissions. Perhaps I'm kicking myself for keeping them in my trouser pockets for 2 years, without even considering the emission of X-rays.
I've no idea what sort of activity is in the lamp - but some sources have suggested about 50 MBq
The marketing information mentioned that the beta particles would be contained by the acrylic shell of the keyring. A not unreasonable claim given the low energy of the tritium beta emission, and lack of associated gamma.
The keyring itself consists of a thin tritium filled glass rod about 25 mm long, and 1-2 mm in diameter. This is embedded in an acrylic cylinder about 8 mm in diameter.
Out of curiosity, I tested one of these keyrings with a GM counter and was somewhat surprised to find it recorded about 100 c/s above background. Presumably this is due to bremsstrahlung generation in the acrylic.
I'm wondering whether this sort of activity is typical of such a device. I was under them impression that the acrylic was a poor generator of bremsstrahlung, so didn't really readily detectable emissions. Perhaps I'm kicking myself for keeping them in my trouser pockets for 2 years, without even considering the emission of X-rays.
I've no idea what sort of activity is in the lamp - but some sources have suggested about 50 MBq