A Geiger counter can only tell you if you're being irradiated at the current time, not how much radiation dose you have accumulated. It also doesn't tell you what type of radiation you're absorbing, or what energy.
If this is actually possible in the US, find your state/country's Radiation Protection agency, one that will issue you with a thermoluminescent dosimeter (TLD) or something. Actually, they should issue you with two of them. Both should be carried with you on the flight to and from Kiev, but only one TLD should come with you on your tour of Chernobyl. They can use one as a means of measuring background radiation from the flight and your surroundings, and one to measure the dose you got on your tour.
this is very likely the best spot recommendation of the thread (my old Nucular ed from my conscript service is simply too rusty)
also:taking iodine pills just in case to prevent radioactive iodine getting stored by your body is also a usual safety measurement you might take
Oh, and post the results. I want to see numbers.![]()
i second that