[Errant]

I was just thinking where I could get a very sensitive Geiger counter for a good price.

You can build your own using an arduino board and about $150 in a detector and other parts that is equal to those costing upwards to $800, that will detect Gamma, Beta, and even Alpha rays/particles.

[Procyon]

Turn on the Geiger counter and you will needlessly scare yourself. You will discover everything is radioactive. Radon is seeping from the ground. Your milk has measurable amounts of radioactive calcium. Even the bones if your sleeping partner are radioactive.

[Gaffer]

Thanks