Ernest Lawrence a scrap of a paper napkin. While sitting in the library one evening in 1929, Lawrence glanced over a journal article by Rolf Widerøe, and was intrigued by one of the diagrams. This depicted a device that produced high-energy particles by means of a succession of small "pushes". The device depicted was laid out in a straight line using increasingly longer electrodes. At the time, physicists were beginning to explore the atomic nucleus. In 1919, the New Zealand physicist Ernest Rutherford had fired alpha particles into nitrogen and had succeeded in knocking protons out of some of the nuclei. But
Nitrogen triiodide Nitrogen triiodide Nitrogen triiodide is the inorganic compound with the formula NI. It is an extremely sensitive contact explosive: small quantities explode with a loud, sharp snap when touched even lightly, releasing a purple cloud of iodine vapor; it can even be detonated by alpha radiation. NI has a complex structural chemistry that is difficult to study because of the instability of the derivatives. Nitrogen triiodide was first characterized by Raman spectroscopy in 1990 when it was prepared by an ammonia-free route. Boron nitride reacts with iodine monofluoride in trichlorofluoromethane at −30 °C to produce pure NI in low yield: