The cyclotron is a particle accelerator that uses an electromagnet and vacuum environment to take an initial voltage and amplify it several times and shoot out particles. It was invented by Ernest Lawrence in 1932 and he was awarded the Nobel Prize in physics for this invention in 1939 (1). Lawrence was said to have initially shot “every available projectile at every available target” in the hope of breaking into and shattering the nuclei of every atom (2). Commonly used projectiles included protons, helium nuclei, as well as deuterons (the nucleus of deuterium atoms). In 1935 Lawrence shot deuterons against the element lithium and obtained helium. Jean and Irene Joliot seemed to have discovered the phenomena of artificial radioactivity by shooting protons, sped up to 600,000 volts, at lithium fluoride crystals. They saw visual flashes of helium atoms striking a special zinc screen. Similarly, Lawrence’s lab discovered 120 artificially produced radioactive substances. One of the more interesting of these was radioactive sodium with a half-life of 15 hours. Radioactive sodium produces gamma rays with energies close to 5.5 million volts, which is almost three times the penetrating power of the gamma rays given off by decaying radium. Radioactive sodium was used in cancer therapy as a substitute for x-rays and radium as well as being used as a radioactive tracer for medical research (2).

References

(1). http://en.wikipedia.org/wiki/Cyclotron , accessed 4 April, 2015.

(2). B. Jaffe. Crucibles: The Story of Chemistry, Dover Publications, Inc., New York, USA, (1976) pp. 265-282.