He told me later that he spit out his port, he was so shocked. Well, you know that opposite charges attract. At a high voltage there's a lot of positive charge, so a negatively charged electron is attracted to the charge, and it moves very quickly to get to it. By moving toward the charge, the electron gets smashed into pieces and you can watch what happens next. Linear accelerators are ones that are just a straight tube.
Cyclotrons go in spirals, and are a much more efficient method of accelerating particles.
Mine were about four and a half inches in diameter. My grandfather was a mechanical and electrical engineer and he did a lot of ham radio stuff. And from sparks, it's really a short leap to physics and particle accelerators. I also do a lot over the summers. This past summer was the third I've spent at Fermilab, and I designed a new system of accelerating.