Again in the early 1930’s, E.O. Lawrence who was also an American physicist developed the Cyclotron. This device is capable of accelerating charged particles (protons) in a circular path to energies that exceed 10 MeV. The Cyclotron is comprised of a large cylindrical box sandwiched between the poles of an electromagnet. The box is evacuated until a high vacuum exists. Charged particles are fed into the cylindrical box. Two `D’ shaped electrodes placed back to back with a gap between them are connected to a high voltage source inside of the box. By rapidly reversing the electric charge on the electrodes, and due to the presence of the magnetic field of the electromagnets, the charged particles move in a circular fashion. Each time the charged particles cross the gap of the electrodes, the particles gain energy and begin moving towards the outside of the cylindrical box. Once the charged particles reach the outer edge of the box, they are deflected towards the target, resulting in high energy X-radiation.


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