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How did Ernest Lawrence and M. Stanley Livingston develop the first cyclotron?

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Diagram of a linear proton resonance accelerator, or linac, showing protons entering from a source, passing through a series of labeled drift tubes powered by a radio-frequency source, and exiting as a beam through a cavity. — particle accelerator The accelerator is a large-diameter tube within which an electric field oscillates at a high radio frequency. Within the accelerator tube are smaller diameter metallic drift tubes, which are carefully sized and spaced to shield the protons from decelerating oscillations of the electric field. In the spaces between the drift tubes, the electric field is oriented properly to accelerate the protons in their direction of travel.

Ernest Orlando Lawrence conceived the idea for the cyclotron in 1929 as a modification of Rolf Wideröe’s linear resonance accelerator. To develop the device, Lawrence tasked his student, M. Stanley Livingston, with building a prototype.12

In 1931, Livingston successfully demonstrated the principle of the cyclotron by constructing a device that accelerated hydrogen ions (protons) to 80 keV. Following this success, Lawrence and Livingston built a second, more powerful cyclotron that accelerated protons to 1.2 million electron volts (MeV), providing sufficient energy to induce nuclear disintegration.12

The design of these early cyclotrons featured two hollow, D-shaped electrodes known as dees, which were placed in an evacuated chamber between the poles of an electromagnet. A radio-frequency oscillator created an alternating electric field in the gap between the dees, causing particles to spiral outward as they gained energy. This invention earned Lawrence the 1939 Nobel Prize for Physics.341