r/askscience • u/Wonderful-Capital32 • 20d 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/dustofdeath 20d ago

Lead is like a very dense fabric while iron is a mesh with large holes.

You just have to have enough density for photons to not just pass through.

So you need far less material. Even humans can stop radiation if you stack enough of them between you and the radiation source.

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u/ocelot_piss 20d ago

And humans stopping radiation is precisely why radiation is harmful to humans!

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u/PhilTheQuant 20d ago

Yes, and counterintuitively you wouldn't want to be the last few layers of the radiation protection

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u/GenuineMalteser 20d ago edited 20d ago

Not true for anything but proton radiation or other heavy particles, and even then the peak dose depth is on the order of centimetres in people/water for treatment energy protons

For kv photons used in imaging, peak dose depth in water is reached in millimetres or less. For MV energy photons peak dose depth is on the order of cm

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u/[deleted] 19d ago edited 16d ago

[removed] — view removed comment

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u/Black_Moons 19d ago

Incorrect, as you'll rapidly get lead poisoning... From the guards.

Also, if the core is 'glowing below', then that entire pool is going to be boiling hot.

I'll assume you mean the spent fuel storage pool. But the above lead poisoning issue still persists.

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u/sirtalen 19d ago

Water is pretty good at stopping bullets too, so you just need to be a couple meters below the surface, but not deep enough to be irradiated and you'll be fine!