>>13660959Attenuation coefficient is for photon radiation (uncharged and no mass). We're discussing nuclear radiation
Radiation shielding is multi-layered because we have different types of radiation that reacts differently to different materials
Lead is awesome because it is dense.
But this density can be its own downfall because its electrons can be hit by a beta and can cause a cascade of X-rays via bremsstrahlung
X-ray can be more dangerous to tissues than beta.
Neutron and Alpha are powerful and the best defense against them is water as it can bleed their kinetic energy with every collision, slowing them down. But every collision converts the kinetic energy to gamma rays which then causes free radicals on the water (hydrogen peroxide)
Gamma rays are just photons but they can still damage your DNA. To defend, you need either 13 feet of water, or 1 meter of lead.
As such, the first layer is water, then lead, then concrete. There can be modifications of course using boron, iron, plastics, etc.
>>13660568Made an honest mistake. It's actually 13 feet of water to defend against gamma. And Lead is actually bad for Neutron shielding precisely because it is dense
Neutron has no charge and completely unaffected by Coulomb repulsions and therefore cannot be slowed down by Heavy nuclei.
It must instead face Hydrogen because it is even lighter than a neutron and would be capable of slowing it down.
Think of light nuclei as ping pong balls vs a steel pellet
The ping pong balls would absorb the speed of the steel pellet till it finally comes to a stop and decay into a proton
However, if a steel pellet collides with a cannon ball (heavy nuclei) it would not lose momentum at all.
Free Neutrons have a radiation weighting factor that ranges from 5 all the way up to 20 (highest) depending on the energy
I was just thinking of neutron activation but this is a pretty diverse topic and neutron activation really is nasty, alright
