I'd guess you still need to maintain them and confirm their accuracy. Tuning a Geiger counter seems more niche then tuning a humidity sensor.
I'd guess you still need to maintain them and confirm their accuracy. Tuning a Geiger counter seems more niche then tuning a humidity sensor.
I don’t know… we have radioactive elements with a very long half-life, which I assume would be great for calibration: somewhat safe and low activity, so good match for atmospheric concentrations of common radionuclides