[antognini]

Yes, this is why the idea to use Po-210 was a stroke of (evil) genius. Because of its unique decay profile it is extremely hard to detect. The FSB agents who did this could obtain a small but lethal dose of Po-210 in Russia and then carry it across borders dissolved in a vial of water. In that state it is not dangerous, so the agents had little risk to themselves by carrying it. And it is also undetectable by border security, even if they were monitoring for radiation.

[misja111]

Thanks for all the great insights! But why was the Po-210 not dangerous in that vial of water? It seems many people who got in touch with it got ill: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767288/

[FormFollowsFunc]

According to another article the glass wall of the vial stops the radiation.

https://www.argonelectronics.com/blog/litvinenko-and-the-per...

[Gare]

That was after they opened it.

Also, from the article:

> The UK Health Protection Agency, which is advising authorities on technical aspects of the case, characterises the contamination in all 12 cases as “not significant enough to result in any illness in the short term,” while “any increased risk in the long term is likely to be very small.”

[jojobas]

When alpha particles are stopped by anything, secondary x-rays are created. I wonder if airport x-ray machines are sensitive enough to pick that up.

[brippalcharrid]

It would probably just appear as faint noise, and then only if it happened to be at wavelengths that the sensors were tuned to detect, and which the machine's signal processors weren't trying to ignore, and if the image processing was designed to draw attention to it.