This is the one I have,,,used to be cheaper,,,
think it is about 13 years old,,,still working,,,
clicking on background radiation,,,does Alpha,,,Beta,,,and Gamma,,,
the sensitivity on beta is very good,,,if you research this stuff...
Alpha above 3.0 MeV
Beta above 50 KeV
Gamma above 7 KeV
The geiger tube comes with a black boot to protect the thin mica end window. This boot needs to be removed to detect alpha particles. However, gamma and beta particles will pass through the boot and be detected.
The United States has declared that this product for restricted exporting to foreign countries. It may still be possible, but will require additional information prior to shipping.
I have the one with the wand,,,used to be 150 dollars kit,,,
GCA-02 Analog Geiger Counters
This Geiger counter outputs audible click and will blink a LED with each radioactive particle it detects. In addition it has two digital outputs that may be connected to a number of accessory instruments; a data logger, Digital Meter adaptor that outputs an approximate radiation level, RS-232 adaptor to plot radioactivity on a PC.
so,,,guess the gas hasn't leaked out of mine yet,,,13 years...
if you do the kit,,,you need to know a little about electronics,,,
and need to set the high voltage supply just right,,,so you get the
sensitivity without arcing the tube...otherwise get the assembled...