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Primer: Lawrence’s Cyclotron December 3, 2008

Posted by Will Thomas in EWP Primer.
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In the early 1930s, the acceleration of electrons and protons was a popular project.  While the spectacular theoretical developments in quantum mechanics had stolen the show in physics in the 1920s, the problem of understanding the atomic nucleus had also become a subject of renewed interest following on experiments performed by Ernest Rutherford and his coterie at the Cavendish Laboratory at Cambridge University.  They had shown that bombarding nuclei with the natural radiation of radioactive materials could transmute the subject nuclei into different elements.  However, natural radioactive materials were expensive, and their ability to provide incident particles was uncontrolled and inefficient.  It was understood that providing some artificial source of high energy (high velocity) particles would make bombardment easier, and the exploration of atomic nuclei more systematic and reliable.

Edwin McMillan and Ernest Lawrence. Credit: Lawrence Berkeley National Laboratory, courtesy AIP Emilio Segre Visual Archives, Fermi Film Collection

The obvious means of creating a source was to send particles streaming across a high electrical potential difference (high voltage).  Lightning accelerated electrons in an uncontrolled way between the sky and the ground—and had, in fact, been marshaled as a source of ephemeral high voltages.  The electrical industry had been vigorously seeking ways of creating high voltages so as to transmit electricity over long (more…)