[raverbashing]

You are right of course, but the effects you're describing are kind of what I meant

Yes, I don't think there is a magic material that will perfectly resonate with high energy gamma rays. But evolution might be able to figure it out. Maybe "resonance" is more specific, and "interaction" is better.

My criticism was more to the " you need thick material to stop radiation" whereas the answer is more "we need thick material because that's the best material we know for the job". Glass is opaque to UV which is more energetic than visible light for example.

And not to forget we know if some materials that do absorb gamma rays, the issue is that they like to go boom after doing that https://en.m.wikipedia.org/wiki/Photofission

[acidburnNSA]

Just quick response on the last point: Photofission reactions happen all the time in places like nuclear reactors. There are no materials that I'm aware of that photofission explosively. The photofission reactions are generally very rare compared to all the other reactions. Heck, natural uranium in your kitchen counter spontaneously fissions all the time but that doesn't lead to an explosion because 1 million atoms is a lot less than 1e23 atoms. Am I missing something?

[raverbashing]

Agree, go boom is a bit of an exaggeration, I meant that you probably don't want materials that undergo fission while absorbing your radiation