This will be hosted at either Brookhaven National Lab (NY) or Jefferson Lab (Virginia). Unfortunately, National Labs need to find new large construction projects to justify their continued existence, and there aren't enough big science projects to go around. The European model of sharing a single facility (CERN) is much more sensible in that it decouples scientific prioritization and the issue of local jobs.
It's a collider of electron on proton/ion beams.
There are two candidate sites: Jefferson Lab (Newport News, Virginia), which already has a electron beam (CEBAF). And Brookhaven National Lab (Brookhaven, Long Island, New York), which already has an ion beam.
This suggestion is for an electron beam, and they radiate sybchrotron radiation like crazy when you make them turn at high energies. So building it in a circular tunnel is a good idea if you want to make a x-ray source or a lot of radioactive rock.
I wish that would happen, the SSC design is even more powerful than LHC. But not sure Texas is culturally the optimal place for such high science these days. Part of the opposition to SSC back in the day was religious. CA or NV might be better.
PS - part of the opposition to the LHC also was religious. Remember people objecting to humanity deliberately searching for the “God Particle”, aka Higgs Boson, which the LHC was specifically designed to find? Probably not the best word choice on the part of the scientific community, unless they were deliberately trying to troll the 20-30% of the population that treats religion literally. There were similar undercurrents reaching all the way up to Congress during the SSC’s life.
More importantly, the SSC site was sold to private industry more than a decade ago.