[DBrow]

You know, thinking about this a bit more, the sensors don’t even measure RAD or REM. If it’s a pocket pen, it’s the loss of charge in a little spring electrometer, as the radiation changes the charge the little quartz fiber moves and what you actually measure is the delta distance, which is turned into REM by the calibration of the scale.

And an electrical-type ion chamber measures picoamps of radiation-induced charge in air. A GM tube counts discharges, and the clicks are integrated.

A PIN diode measures current.

A TLD measures the thermally-induced glow in a crystal, CaF2 or LIF or similar, as the heat releases radiation-induced trapped electrons.

Outside of a calorimeter (I’ve used a graphite calorimeter at SATURN), I can’t think of a direct RAD or REM sensor. Even the calorimeter measures temperature, not radiation directly.

Off topic, sorry, all.

[MHGinTN]

HAH! That’s easy for you to say ..

[bvw]

Not really, that kind of stuff is on target. If you can understand that you have to use different kinds of sensors to measure radiation, you can also understand that the body in whole, the systems of the body (like the deeper skin layers), the cells and the substructures within the cells all have variant responses to different kinds of radiation and even different dosings over time.

For example, human A is exposed exposed over a year to a daily low dosage of radiation. Human B is exposed to the same total but in bursts with a few hours between them. And Human C gets the whole dosage in one shot. All get the same Rem dosage for a year.

Both human A and human C end up healthy. Human C picks up some radiation-induced problem. Why? Because low dosages over time the body can handle in normal operation, and trauma level dosages cause the body's emergency systems to kick in to repair and limit the damage, but in the middle, the damages are too much over time for the normal metabolism, but too low for the emergency systems to kick in.