Thorium lenses

[frame-it]

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the lens ive been craving for quite a while and finally found & bought a mint copy last month has quite high radiation,  the images are really nice.

 

[Anbaric]

8 hours ago, frame-it said:

the lens ive been craving for quite a while and finally found & bought a mint copy last month has quite high radiation,  the images are really nice.

That's about a dental X-ray an hour, isn't it? Another lens not to use as a loupe or keep in your trouser pocket!

[nitroplait]

 

20 hours ago, frame-it said:

the lens ive been craving for quite a while and finally found & bought a mint copy last month has quite high radiation,  the images are really nice.

I don't know how fast reacting the meter is, but it looks like the readout drastically lowers just a few cm. away from the lens? Did you notice how the fall off was, say 5 or 10cm away?

It could be interesting to measure just behind the camera - where your face is located in a normal shooting situation. I am guessing the shielding of the camera makes it is close to nothing.

11 µSv/h isn't much anyway, unless you sleep with it every night.

You would have to hold it close to a body part for 150 hours to get as much radiation at that spot, as a flight attendant get exposed to from all sides on their hole body over a year. 

[Anbaric]

If it were a point source, the dose reduction would follow the inverse square law - if you started 1cm away, the dose would drop to 1/25 of the original at 5cm, and to 1/100 at 10cm. The lens is a bit big to be considered a point source at these distances, but you should get roughly that reduction. But that's also why using one as a loupe would be bad. You get 100x the 1cm dose at 1mm, right next to a very radiation sensitive organ.