Yeah, the giant ass antimatter particle accelerator thing was just an additional silly thought. This is probably a strange way to go about making a ringworld, but I think it could work.

So, how would you build a ringworld, Nano?

Edit: Oh, in addition, as I said previously, you could cover the inner surface of the ringworld with solar panels and make the ring a bit thicker so the residents of your ringworld would instead live 'inside' of it, y'know? I think an entire ringworlds' inner surface area, covered in solar energy gathering devices, could probably power plenty of shit like big particle accelerators to make antimatter with.