Vintage radioactive wrist watches - Is Radium really nasty?

[Katie Wasserman]

(01-18-2015 11:19 AM)jebem Wrote:  While the kit works fine, I'm not happy with the 500VDC high voltage DC-DC converter circuit because it consumes about 20mA from the 9V batteries.
This is too much. I have built my own high voltage DC-DC converter circuit consuming only about 4 mA under load.
But I'm too lazy to redraw the PCB to replace the circuit. So it will stay as it is for a while.

Very nice work (and great pictures, as usual)!

I've made some tiny little GM tube detectors/counters too and did a little better on my home made high voltage supply specs (under 100 ua at 6 volts input). However that's still not good enough for me.

I prefer to use the LND-712 tube as it has a mica window to allow in alpha particles, but it's much more expensive (and fragile) than the Russian tubes.

For the power supply I've been using these incredibly tiny, efficient modules:

http://www.ebay.com/itm/Geiger-counter-p...257eaa7ce3

Which will power the tube for over a year on a single CR2032. You can ask the seller to customize the voltage for the tube you're using.