Testing authenticity via atmospheric radation during creation?

[JarretGax]

I know that pre-atomic steel/iron is important in making sensitive devices that have to be radiation free to be accurate.  Along this line of thought, would someone be able to test modern fakes of ancient coins made after the 40s that would have this atmospheric background radiation in the metal when made? 

[Joe Sermarini]

I know this would work for once living things because the are constantly absorbing in new molecules (breathing, eating, drinking). And maybe for items made with water like pottery. I don't know how metal would absorb more radiation in its raw state than in a coin state. I'm not sure the test will detect any difference in a modern vs. ancient coin.

[SC]

"Pre-atomic steel" is a "thing" because steel and iron interact with some of the radioactive Cobalt-60 that exists due to atmospheric nuclear testing.

What I am not sure of is whether the same thing applies to copper or silver, from which coins are made, or if it could be measured with any accuracy.  The fact it is used for the most sensitive instruments implies the level of radioactivity is very very low.

Maybe someone knows better.

SC
 

[JBF]

One source for pre-atomic steel is WWII ship wrecks (or before), the foundry process post atomic has "problems" with atmospheric cobalt entering the mix.  I mention this so anyone reading this can have some idea of what is being discussed.  I don't know of any reason why gold or silver would be effected (or for that matter, would not be effected).  It is an interesting idea, though.  My guess is that cobalt chemically acts like iron, silver and gold do not.

[esnible]

A few years ago I read "Ancient Roman Metal Used for Physics Experiments Ignites Science Feud" in Scientific American.  https://www.scientificamerican.com/article/ancient-roman-lead-physics-archaeology-controversy/ .  If Roman lead is needed for equipment it should be possible to tell if lead is ancient.

The Wikipedia article "Low-background steel" explains why pre-WW2 steel is different and how it can be obtained.  https://en.wikipedia.org/wiki/Low-background_steel .  The article points out that air is used in the production of steel.  I don't think that is the case with coin metals.  Not much air is needed to turn a gold nugget into a coin flan.  So the radionuclides in the air will not make it into the flan.

[SC]

I think you are right Ed.  The processes (ie Bessemer) the article speaks of don't just blow air into the crucible - they apparently blow air through the molten metal.  Nothing like that is required for Cu, Ar, etc.

SC