[DBrow]

I forgot to mention- for your target element I'd pick Carbon, because tht's what we are made of other than water.

I ran the transport with a Gold shield at 10 g/cm2 (a 4x4 inch piece of shield would weigh about 2 1/4 pounds) and you can see that at low E, you get orders of magnitude of shielding. At 100 MeV/nucleon you get roughly a factor of 100. From 200MeV/nucleon out, though, very little shielding is seen. Even a thick gold shield does not stop much of the high energy particles.

Anyhow the calculator is fun to play with.

For a real serious particle transport tool look at

www.srim.org

[lepton]

From 200MeV/nucleon out, though, very little shielding is seen. Even a thick gold shield does not stop much of the high energy particles.

At that level, do we absorb?

As far as shielding, if radiation occurs within the shielding, then it seems obvious that spaced shielding would work better than just more thickness, where you have an open buffer zone before reaching the inner shielding.