Lawrence conceived of a way around the impossible. He suggested that a machine could be built that used relatively small 25,000-volt potential to accelerate protons back and forth in an alternating electric field. By means of vacuum tubes and an electromagnet, the ion particles might then be accelerated by the electric field to greater and greater speeds along a spiral path. He was not sure how big an accelerator had to be to penetrate an atom’s nucleus—but he was convinced that with a large enough magnet and a big enough circular chamber, he could break the million-volt mark.
