spark gaps and potassium isotopes

[Opcom]

I have been going through my spark gap tube collection and checking to see if any were radioactive. I noted that some had a radiation symbol on them but it is supposed to be harmless and for the little bit of isotope gas to help the gap conduct as far as I know. The purpose is to see of any would make a useful protective spark gap in the bigger transmitters, but to weed out any that might actually be best kept put away. None gave any reading at all with the military PDR set.

I already had them put all of them back in the "spark gap/TR tube" box here and I had left the counter on, sitting on the box, because it is so seldom used, figured a half-hour of running time would do it some good, and my friends Scott and Steve showed up with some tacos and the Geiger picked up quite a bit as soon as they came in. Steve has just had some kind of injection at the hospital where they look for cancer. I tested close and at his side was something like 2.5mR of Gamma. Much more with the Alpha window open which is impressive considering it is stopped more easily. He said it was a potassium isotope and he can't go home for 24 hours because his wife is embarazado.

At least it was not my vacuum tubes. How long at 2.5mR is unhealthy? It is probably much stronger inside his body, wherever it is accumulating probably the kidneys on its way out.

[KA0HCP]

Let's just say that when he snores tonite his tongue and uvula will be putting on a shadow show on the ceiling. 

Not really.  2.5 mrem is fairly low considering at sea level the average person gets around 100 mrem a year.  Still it's better for him to sleep on the couch for a few nights.

bill