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Edwin McMillanAmerican physicist, Nobel Prize in Chemistry, 1951, shared with Glenn T. Seaborg
Date of Birth: 18.09.1907
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Content:
- Early Life and Education
- Research at Berkeley and Cyclotron Development
- Discovery of Neptunium and Plutonium
- Manhattan Project and Wartime Research
- Post-War Career
- Synchrotron Development
- Nobel Prize and Later Career
- Personal Life and Legacy
Early Life and Education
Edwin Mattison McMillan was born in Redondo Beach, California, on September 18, 1907, to Edwin Harbo McMillan, a physician, and Anna Maria (Mattison) McMillan. In 1918, the family moved to Pasadena, where McMillan attended elementary and secondary school. While at Pasadena High School, he was inspired by public lectures at the California Institute of Technology (Caltech).
McMillan enrolled at Caltech in 1924 and earned his bachelor's degree in physics in 1928. The following year, he completed his master's degree. He received his Ph.D. in physics from Princeton University in 1932 for his dissertation on molecular beams.
Research at Berkeley and Cyclotron Development
After Princeton, McMillan worked as a National Research Council fellow at the University of California, Berkeley. In 1934, he joined Ernest O. Lawrence's Radiation Laboratory at Berkeley. There, he contributed significantly to the advancement of cyclotron technology, nuclear physics, and chemistry.
Lawrence's cyclotron accelerated protons and atomic nuclei to high energies using a magnetic field to keep the particles in a circular path. A rapidly oscillating electric field synchronized with the particles' orbits further accelerated them.
Discovery of Neptunium and Plutonium
In 1938, German scientists Otto Hahn, Fritz Strassmann, and Lise Meitner discovered nuclear fission in uranium. McMillan, inspired by Enrico Fermi's work, set out to study the effects of bombarding uranium with neutrons. In 1940, he and Philip Abelson observed the formation of a new element, neptunium, which had 93 protons. This discovery marked the first synthesis of a transuranium element. McMillan's research laid the groundwork for Glenn T. Seaborg's subsequent discovery of plutonium in 1941.
Manhattan Project and Wartime Research
During World War II, McMillan contributed to the war effort by working on sonar, microwave radar, and the nuclear weapon project. He worked at Berkeley, the Massachusetts Institute of Technology (MIT), the U.S. Navy Radio and Sound Laboratory in San Diego, and the Manhattan Project in Los Alamos.
Post-War Career
After the war, McMillan became a professor of physics at Berkeley. In 1954, he became associate director of the Radiation Laboratory, and from 1958 to 1973, he served as its director (the laboratory was renamed the Lawrence Berkeley Laboratory in 1971).
Synchrotron Development
In 1945, McMillan addressed a limitation of the cyclotron: the particle's period of rotation becomes desynchronized with the applied electric field as its mass increases due to relativistic effects. McMillan proposed varying the magnetic field or frequency to compensate for the decreasing speed of the particles, resulting in constant-radius orbits known as synchrotrons. (McMillan was unaware that Soviet physicist Vladimir I. Veksler had made a similar proposal.) The energy achievable in synchrotrons is limited by factors such as their size and the magnetic field.
Nobel Prize and Later Career
In 1951, McMillan and Seaborg received the Nobel Prize in Chemistry for "their discoveries in the chemistry of the transuranium elements." McMillan's work in accelerator development also contributed to the advancement of nuclear chemistry.
After receiving the Nobel Prize, McMillan continued his research until his retirement from Berkeley in 1973. He served on numerous scientific and policy-related organizations, including the U.S. Atomic Energy Commission, the Rand Corporation, the International Union of Pure and Applied Physics, and the Stanford Linear Accelerator Center.
Personal Life and Legacy
In 1941, McMillan married Elsie Bluemer, the daughter of the dean of Yale Medical School. They had a daughter and two sons. In addition to the Nobel Prize, McMillan received the Research Corporation of America Award (1951) and the Ford Motor Company's "Atoms for Peace" Award (1963).
Edwin McMillan passed away in El Cerrito, California, on September 7, 1991. His contributions to nuclear physics and accelerator technology have had profound impacts on both science and society.