It hadn't occurred to me that there would be significant energy contained in a beam of sub-atomic particles. Something like 100kg TNT equivalent (~500MJ)? Wow.
https://www.symmetrymagazine.org/article/parking-the-lhc-pro...
"Enough stored energy to melt a ton of copper"
"The beam dump is a solid graphite cylinder 8 meters long and under a meter in diameter. It’s wrapped in a stainless-steel case, filled with nitrogen gas, and surrounded by iron and concrete shielding."
There are accelerator-driven fission reactor ideas that would use ~1 GeV protons (much less energetic than the protons here) to produce neutrons to drive a subcritical target. These might be useful to destroy certain nuclear waste isotopes.
Also static magnetic fields don't "do" work, by that I mean, that you can not extract energy from a magnetic field by sending particles through it: The Lorentz force is perpendicular to both the movement of the particle through the field, and perpendicular to the field itself. Hence taking the inner=scalar=dot product of the force vectors and trajectories they come out as 0, i.e. no work is done.
You need dynamic magnetic fields to do work.
I was always like "Yeah that's just a small beam and the magnets are to navigate it in circles". In retrospect it does make sense now why people were concerned about the collision of such beams.