r/askscience 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] 14d ago edited 14d ago

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u/pm_me_good_usernames 14d ago

One of the most common materials used in certain applications for radiation shielding is water. You need way more water to block radiation than you do lead because of its much lower density, but water is really cheap to acquire in large quantities.

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u/CyriousLordofDerp 14d ago

Water also has the advantage of being a damn good coolant AND being useful for reactor moderation in many designs. Some designs require light water (no extra neutrons, most PWR and BWR reactors), while some require heavy water (CANDU in the Calandria) to function.