What physics needs is a revolutionary (not evolutionary like the SSC or the LHC) particle accelerator.

There are promising works with high-powered lasers, for example: https://www.youtube.com/watch?v=hcGgaa2mFc4

But it seems the "spin particles really fast in a very long circular tube" is reaching the end of its life.

A senior scientist told me they grow mushrooms now in that tunnel ;-)