Edwin M. McMillan, Neptunium,
Phase Stability, and the Synchrotron

Resources with Additional Information · Patents · About Edwin McMillian
Transuranium (Heavy Elements) · McMillan in LBNL History

Edwin M. McMillan
Courtesy of Lawrence
Berkeley National Laboratory

'For many years, scientists believed that Uranium, with its atomic weight of 92, was the upper limit of the periodic table. But in 1940, more than a century and a half after Uranium was first discovered, UC Berkeley physicist Edwin M. McMillan, working with Philip Abelson at Lawrence Radiation Laboratory, boosted the number of known elements to 93. Neptunium led the way for the discovery of many other elements heavier than Uranium and the development of various nuclear fuels. …

With the aid of the cyclotron …, McMillan and Abelson conducted their ... fission experiments and eventually produced a true sample of element 93. Following the naming of uranium, the new element was dubbed neptunium for the next planet out in our solar system. …

In 1951, McMillan and [Glenn T.] Seaborg shared the Nobel Prize in Chemistry for their "discoveries in the chemistry of transuranium elements."

[I]n 1958, McMillan was appointed director of the Lawrence Radiation Laboratory at Berkeley and Livermore. Shortly after, he discovered "phase stability," a principle that massively increased the energy of particle accelerators. The findings led to McMillan's invention of the synchrotron, still a key instrument in nuclear physics research.'1

1 Edited excerpt from 1940: Edwin M. McMillan and the Transuranium Triumph; ScienceMatters@Berkeley, Volume 1, Issue 7


Resources with Additional Information

Additional information about Edwin Mattison McMillan is available in electronic documents and on the Web.


Focusing in Linear Accelerators, DOE Technical Report, August 1950

A Thick Target for Synchrotrons and Betatrons, DOE Technical Report, September 1950

The Transuranium Elements: Early History (Nobel Lecture), DOE Technical Report, December 1951

Notes on Quadrupole Focusing, DOE Technical Report, February 1956

Some Thoughts on Stability in Nonlinear Periodic Focusing Systems, DOE Technical Report, September 1967

Some Thoughts on Stability in Nonlinear Periodic Focusing Systems - Addendum , DOE Technical Report, March 1968


Additional Web Pages


About Edwin McMillan:


Transuranium (Heavy) Elements:


McMillan in Lawrence Berkeley National Laboratory (LBNL) History:

Part Two: Forging a National Laboratory System in a Time of Peril – An Historical Perspective on [Berkeley] Lab's Legacy: A Year-Long Series in The View

Part Four: Holding a Steady Course Through a Turbulent Decade – An Historical Perspective on [Berkeley] Lab's Legacy: A Year-Long Series in The View


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