Most of the Geiger counter manufacturers say to calibrate their instruments annually or semiannually, which at $75+ a pop adds up over the years.
Is it really necessary?
If I periodically perform a test on a known long half-life sample at the same distance (like in some kind of jig), and get the same reading as when I first did it with a calibrated instrument on every scale could I assume it is still working and “calibrated”?
Also it seems unlikely it would lose more than +- 5% accuracy at the most, unless something went bad like capacitors.
That coupled with the Geiger counters already “fuzzy” accuracy of +-20%, I don’t see why it would be necessary.
But maybe the Geiger tube itself changes over time, and gives different readings?
Thanks for any light you can shed on the subject.