What is the origin and meaning of “3.6 roentgen, not great, not terrible”?
In: Physics
A Roentgen is a unit of radiation exposure named after Willhelm Roentgen, a German scientist who discovered the x-ray.
By US federal regulations radiation workers aren’t allowed to be exposed to more than 5 rem (Roentgen Equivalent Man) per year.
So Roentgen is basically exposure through air, rem is how much of that exposure is actually absorbed by the body.
The primary concern with chernobyl was gamma rays which have a multiplying factor of 1, therefore Roentgen to rem is roughly 1 to 1 so we can roughly correlate 3.6 Roentgen to 3.6 rem.
So the rule is 5 rem per year and they were being exposed to 3.6 rem per hour.
The reason he said “not great not terrible” is that at 3.6 rem per hour you can still get emergency work done as long as you only spend a few minutes in the radiation field. And open exposure to the core could have dose rates at hundreds to thousands of rem per hour.
So it wasn’t a great dose rate to be working in but could have been much worse, little did he know it actually was much worse.
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