Editing Edwin McMillan (section)

==Lawrence Berkeley Laboratory==
[[File:HD.1A.009 (12662188285).jpg|left|thumb|McMillan (left) with [[Ernest Lawrence]] (right)]]
In 1932, McMillan was awarded a [[National Research Council (United States)|National Research Council]] fellowship, allowing him to attend a university of his choice for postdoctoral study. With his PhD complete, although it was not formally accepted until January 12, 1933,<ref name="Oral1" /> he accepted an offer from Ernest Lawrence at the [[University of California, Berkeley]], to join the [[Berkeley Radiation Laboratory]], which Lawrence had founded the year before.{{sfn|Lofgren|Abelson|Helmolz|1992|pp=118–119}} McMillan's initial work there involved attempting to measure the [[magnetic moment]] of the [[proton]], but [[Otto Stern]] and [[Immanuel Estermann]] were able to carry out these measurements first.<ref name="Oral1"/>{{sfn|Jackson|Panofsky|1996|pp=217–218}}

The main focus of the Radiation laboratory at this time was the development of the [[cyclotron]], and McMillan, who was appointed to the faculty at Berkeley as an instructor in 1935, soon became involved in the effort. His skill with instrumentation came to the fore, and he contributed improvements to the cyclotron. In particular, he helped develop the process of "[[Shim (magnetism)|shimming]]", adjusting the cyclotron to produce a homogeneous magnetic field.{{sfn|Seaborg|1993|p=288}} Working with [[M. Stanley Livingston]], he discovered [[oxygen-15]], an [[isotopes of oxygen|isotope of oxygen]] that emits [[positron]]s. To produce it, they bombarded [[nitrogen]] gas with [[deuteron]]s. This was mixed with [[hydrogen]] and oxygen to produce water, which was then collected with [[hygroscopic]] [[calcium chloride]]. Radioactivity was found concentrated in it, proving that it was in the oxygen. This was followed by an investigation of the absorption of [[gamma ray]]s produced by bombarding [[fluorine]] with protons.{{sfn|Jackson|Panofsky|1996|pp=217–218}}

In 1935, McMillan, Lawrence and Robert Thornton carried out cyclotron experiments with deuteron beams that produced a series of unexpected results. Deuterons fused with a target [[atomic nucleus|nuclei]], transmuting the target to a heavier isotope while ejecting a proton. Their experiments indicated a nuclear interaction at lower energies than would be expected from a simple calculation of the [[Coulomb barrier]] between a deuteron and a target nucleus. Berkeley theoretical physicist [[Robert Oppenheimer]] and his graduate student [[Melba Phillips]] developed the [[Oppenheimer–Phillips process]] to explain the phenomenon.{{sfn|Jackson|Panofsky|1996|pp=218–219}} McMillan became an [[assistant professor]] in 1936, and an [[associate professor]] in 1941.<ref name="Nobel bio" /> With [[Samuel Ruben]], he also discovered the isotope [[beryllium-10]] in 1940.{{sfn|Seaborg|1993|p=288}} This was both interesting and difficult to isolate due to its extraordinarily long [[half-life]], about 1.39 million years.<ref>{{cite web |url=http://www.nndc.bnl.gov/chart/reCenter.jsp?z=4&n=6 |publisher=National Nuclear Data Center, Brookhaven National Laboratory |title=Chart of Nuclides: <sup>10</sup>Be information |access-date=July 18, 2015 |archive-date=July 12, 2017 |archive-url=https://web.archive.org/web/20170712113701/http://www.nndc.bnl.gov/chart/reCenter.jsp?z=4&n=6 |url-status=dead }}</ref>