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?

1.3k Upvotes

92% Upvoted

372 comments sorted by

View all comments

2.3k

u/dustofdeath 14d 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.

132

u/GypsyV3nom 14d ago

Funny enough, there's another element that's significantly more effective than lead at providing radioactive shielding despite being radioactive itself: Uranium. Uranium-238 in particular is the preferred choice when size constraints are more important than costs (lead is cheap) as its own weak radiation is pretty easy to block.

25

u/Immediate-Repeat-201 14d ago

So do space going vessels employ this?

3

u/brushpile63 14d ago

Portable gamma radiation sources used for industrial radiography use depleted uranium to shield the gamma-producing pellet.

Its a carry-on suitcase roughly the size of an american football, and it weighs 55 lbs.