Does anyone here have any practical experience with radiation detectors? I am talking about devices that can give accurate measurements of background radiation levels in the environment.

I realize that when the "radon levels in houses" issue received a lot of hype. there were people touting "inexpensive home test units". I am highly skeptical of this low-dollar technology. Is there a device that is truly reliable, for a price that is not astronomical?

BTW, just to clarify. I am talking about handheld survey meters. Some models measure only beta and gamma radiation. But some can measure alpha/beta/gamma, and perhaps neutron radiation as well. That's what I am looking for.

Thanks, Pete