I recently bought a GMC-320 Plus geiger counter. I asked to myself...why does it have these measure unit? I mean uSv and mR?! Are these unit related to Energy of the radiation? Geiger muller can't measure the energy...So, I don't understand.
Could you help to understand this thing? Thanks Alex
Yes you are absolutely right. Sievert and Roentgen are related to energy, which a geiger mueller tube can't measure. The GM tube is only telling us like "Oh, I'm hit, hit, again...again" but it does not tell us if it was hit by "small arms fire" or by "artillery grenades".
So what a geiger counter does is, it makes assumptions. Most Geiger counters are calibrated to a specific isotope like cesium137. The Sievert or Roentgen eqivalent which is shown is true only if you in fact measure cesium 137.
Whenever you measure different isotopes the calculated energy shown by the counter is plainly wrong.