I think you want to make a cyclotron. There used to be old-timey science projects in Scientific American ("The Amateur Scientist" section). But they require a level of shop-skills that just don't exist anymore. If you know how to use tools, you know there are risks involved just getting such a device built, and functioning properly, and that there are various risks operating it.
You cannot build a high-vacuum primary pump yourself, let alone the ultra-high vacuum pump, needed for an accelerator, I'm sure; and I don't know if any company is going to sell you such equipment.