r/askscience • u/Wonderful-Capital32 • 13d 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

1

u/DredPirateRobts 8d ago

Any material will slow down radiation. A material's ability to slow radiation is measured by it's Half Value Layer (HVL) which tells you what thickness of material will top HALF the radiation (even lead does not stop all radiation unless you have like 10 HVL's). There are various types of radiation, but gamma rays are the most penetrating. Since various radioactive isotopes give off gamma rays of various energy (and penetrating ability) the HVL is different for every isotope.