Vintage radioactive wrist watches - Is Radium really nasty?

[jebem]

(01-19-2015 03:21 PM)Manolo Sobrino Wrote:  (...) I wouldn't trust or use a G-M tube for dose measurements. Unfortunately DIY people talk about mSv all the time, they have no idea what they're talking about.
(...)
About your G-M tube, I've found this info:
http://gstube.com/data/2398/
According to this, at 500V you're probably operating it beyond its VDC rating (350V-475V), recommended 400V (there is a 260V min, 320V max starting voltage there).

Excellent analysis and useful information, thank you!

This is just one more toy, and as you pointed out, one can not trust the readings as accurate - this is not a lab nor a professional field equipment.
But the readings are real and gives us enough information about the radiation around us. For instance, inside home the background radiation is about 8 to 10 CPM and this value seems to be the usual in many places around the world.

Concerning the high voltage power supply, it is adjustable - when I mentioned 500V is just the nominal initial value - It can be as low as 200V and as high as 900V in this circuit. I'm running it at 400VDC as recommended in the Russian datasheet.

Saludos Cordiales,
Jose