Philips 4C35 and Valvo 5C22 radioactivity?

Molenaar, Thu Dec 29 2016, 05:27PM

I recently acquired a Philips 4C35 and a Valvo 5C22 thyratron, of which I was under the impression that they were not radioactive. The datasheets do not mention in and there are no radioactivity logo's/warnings on the tube. Also a DIY geiger counter (which has not been verified to actually work, since I lack a trustable reference) picks up nothing.

However, at least the JAN 4C35 is radioactive, since it contains Uranium glass. I don't have a UV light source. Are these tubes indeed radioactive or am I worrying about nothing?

If they are, how dangerous are they?