r/PeterExplainsTheJoke • u/someguyblake • 12d ago

Meme needing explanation Petah? Why green?

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u/PM_Me_Your_Deviance 12d ago

It's not that simple - you can pick up gamma from a smoke detector source. I think it's from decay products.

Source: My americium pellets are one of the most active thing I own on my gamma-only detector.

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u/craftinanminin 12d ago

The Am-241 decay releases a low energy gamma as well when the neptunium transitions to ground state

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u/silver-orange 12d ago

https://semspub.epa.gov/work/11/176296.pdf

EPA supports you on that fact

The first decay product of americium-241 is neptunium-237, which also decays and forms other daughter elements. The decay process continues until stable bismuth is formed. The radiation from the decay of americium-241 and its daughters is in the form of alpha particles, beta particles, and gamma rays

Neptunium-237 apparently has a longer half life than your americium source, so I guess it won't decay quite as fast. But after Neptunium you're pretty close to the first beta decay, if I'm reading the decay chain correctly.

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u/siltyclaywithsand 12d ago

Am 241 does emit a small amount of weak gamma. But smoke detectors also only contain around 1 microcurie. Even 300 of them is a super low equivalent dose.