When I worked at a nuclear plant, Chemistry and health physics calibrated their survey meters with a standard source every day. I didn’t work in the C&HP department, so I don’t know if they calibrated them to multiple levels or not. I do remember some guy getting his face scrubbed with duct tape when they found had an emmitting source somewhere on his face. If you could get a standard source - low level - and calibrate your meter yourself, it would probably give you a lot more accurate reading.
Thanks for the tip.
It occurred to me that some entrepreneurial Freeper should turn the concern over Fukushima into a sideline business.
Get a meter. Advertise that you will check people’s groceries for radiation. Keep the price low. Offer to survey incoming seafood, etc. for grocery stores.
Offer to survey farmland and feed for dairies.
It seems like an ideal low-cost-of-entry business.