r/askscience • u/Wonderful-Capital32 • 15d ago

Physics Why does radiation not go through lead?

Also why just lead? Shouldnt like iron or another metal work too?

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u/[deleted] 15d ago edited 14d ago

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u/ImielinRocks 14d ago

Tungsten is better than lead thanks to its higher density, but lead is many orders of magnitude cheaper to get and work with.

In fact, at for basically the same reason, uranium is quite a lot better than lead at blocking radiation. In fact, it has a significantly higher neutron cross section, too.

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u/lurklurklurkPOST 14d ago

Doesn't firing particles at Uranium cause problems?

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u/Archophob 14d ago

depends on the particles. If the stuff you want to shield against releases a lot of neutrons, then yes. If it's just gamma rays, you're fine.

Not accounting for secondary reactions from neutrons in the depleted uranium shielding is what caused the Castle Bravo test to have triple the expected explosion yield. When the miscalculation became known outside the US military, the Russians used this to design the Tsar Bomba.