Without knowing the scale of your friends geiger counter, it is difficult to assess the danger from these old instruments. It makes a BIG difference whether the meter scale is linear or logarithmic. My guess would be that casual proximity would not significantly increase the danger. Just remember that the exposure limits can be reached in two ways: Short-term proximity to a high level source of ionizing radiation or Long-term proximity to a low level source. A good analogy is photographic film exposure where the amount of light falling on the film and the time the shutter is open combine to make a good picture. Some advice--don't take the aircraft clock to bed with you.
Gil Huguley, MVPA17957
Methow, WA, USA
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