Editing Ernest Lawrence (section)

== Development of the cyclotron ==

=== Invention ===
The invention that brought Lawrence to international fame started out as a sketch on a scrap of a paper napkin. While sitting in the library one evening in 1929, Lawrence glanced over a journal article by [[Rolf Widerøe]],<ref>{{cite journal|last = Widerøe|first = R.|author-link=Rolf Widerøe |date =  December 17, 1928 |title=Ueber Ein Neues Prinzip Zur Herstellung Hoher Spannungen|journal = Archiv für Elektronik und Übertragungstechnik|language=de|volume = 21|issue = 4|pages = 387–406|doi = 10.1007/BF01656341|s2cid = 109942448}}</ref> and was intrigued by one of the diagrams.<ref>{{cite web|title=Breaking Through: A Century of Physics at Berkeley. 2. The Cyclotron. |publisher=Bancroft Library, UC Berkeley |date=February 25, 2012 |url=http://bancroft.berkeley.edu/Exhibits/physics/bigscience02.html |archive-url=https://web.archive.org/web/20120527183442/http://bancroft.berkeley.edu/Exhibits/physics/bigscience02.html |archive-date=May 27, 2012 |url-status=dead }}</ref> This depicted a device that produced [[Particle physics|high-energy particles]] by means of a succession of small "pushes". The device depicted was laid out in a straight line using increasingly longer electrodes.{{sfn|Heilbron|Seidel|1989|pp=75–82}} At the time, physicists were beginning to explore the [[atomic nucleus]]. In 1919, the New Zealand physicist [[Ernest Rutherford]] had fired alpha particles into [[nitrogen]] and had succeeded in knocking [[proton]]s out of some of the nuclei. But nuclei have a positive charge that repels other positively charged nuclei, and they are bound together tightly by a force that physicists were only just beginning to understand. To break them up, to disintegrate them, would require much higher energies, of the order of millions of volts.{{sfn|Heilbron|Seidel|1989|pp=46–49}}

[[File:Cyclotron patent.png|left|thumb|Diagram of cyclotron operation from Lawrence's 1934 patent|alt=Strange-looking schematic diagaram]]
Lawrence saw that such a [[particle accelerator]] would soon become too long and unwieldy for his university laboratory. In pondering a way to make the accelerator more compact, Lawrence decided to set a circular accelerating chamber between the poles of an electromagnet. The magnetic field would hold the charged protons in a spiral path as they were accelerated between just two semicircular electrodes connected to an alternating potential. After a hundred turns or so, the protons would impact the target as a beam of high-energy particles. Lawrence excitedly told his colleagues that he had discovered a method for obtaining particles of very high energy without the use of any high voltage.{{sfn|Heilbron|Seidel|1989|pp=83–88}} He initially worked with Niels Edlefsen. Their first [[cyclotron]] was made out of brass, wire, and sealing wax and was only {{convert|4|in|cm|spell=in}} in diameter—it could be held in one hand, and probably cost a total of $25 ({{Inflation|US|25|1934|r=-2|fmt=eq}}).<ref name=cfdmd /><ref name=stroc01>{{cite magazine|url=https://www.llnl.gov/str/October01/Lawrence.html |title=Remembering E. O. Lawrence |magazine=Science & Technology Review |publisher=[[Lawrence Livermore Laboratory]] |date=October 2001 |access-date=August 25, 2013 |archive-url=https://web.archive.org/web/20130615150500/https://www.llnl.gov/str/October01/Lawrence.html |archive-date=June 15, 2013 |url-status=dead}}</ref>

What Lawrence needed to develop the idea was capable graduate students to do the work. Edlefsen left to take up an assistant professorship in September 1930, and Lawrence replaced him with David H. Sloan and [[M. Stanley Livingston]],<ref name=eghhufr/> whom he set to work on developing Widerøe's accelerator and Edlefsen's cyclotron, respectively. Both had their own financial support. Both designs proved practical, and by May 1931, Sloan's [[linear accelerator]] was able to accelerate ions to 1 MeV.{{sfn|Heilbron|Seidel|1989|pp=89–95}} Livingston had a greater technical challenge, but when he applied 1,800&nbsp;V to his 11-inch cyclotron on January 2, 1931, he got 80,000-[[electron volt]] protons spinning around. A week later, he had 1.22 MeV with 3,000 V, more than enough for his PhD thesis on its construction.{{sfn|Heilbron|Seidel|1989|pp=95–100}}

=== Development ===
[[File:Lawrence Compton Bush Conant Compton Loomis 83d40m March 1940 meeting UCB.JPG|thumb|right|Meeting at Berkeley in 1940 concerning the planned {{convert|184|in|m|2|adj=on}} [[cyclotron]] (''seen on the blackboard''): Lawrence, [[Arthur Compton]], [[Vannevar Bush]], [[James B. Conant]], [[Karl T. Compton]], and [[Alfred Lee Loomis]]|alt=Six men in suits sitting on chairs, smiling and laughing]]
In what would become a recurring pattern, as soon as there was the first sign of success, Lawrence started planning a new, bigger machine. Lawrence and Livingston drew up a design for a {{convert|27|in|cm||adj=on}} cyclotron in early 1932. The magnet for the $800&nbsp;11-inch cyclotron weighed 2 tons, but Lawrence found a massive 80-ton magnet rusting in a junkyard in Palo Alto for the 27-inch that had originally been built during World War I to power a transatlantic radio link.{{sfn|Herken|2002|pp=5–7}}<ref>{{cite web|url=http://www.aip.org/history/lawrence/radlab.htm |access-date=September 22, 2013 |title=The Rad Lab – Ernest Lawrence and the Cyclotron |publisher=[[American Institute of Physics]] |archive-date=September 20, 2015 |archive-url=https://web.archive.org/web/20150920022408/https://www.aip.org/history/lawrence/radlab.htm |url-status=dead}}</ref> In the cyclotron, he had a powerful scientific instrument, but this did not translate into scientific discovery. In April 1932, [[John Cockcroft]] and [[Ernest Walton]] at the [[Cavendish Laboratory]] in England announced that they had bombarded [[lithium]] with [[proton]]s and succeeded in transmuting it into [[helium]]. The energy required turned out to be quite low—well within the capability of the 11-inch cyclotron. On learning about it, Lawrence sent a wire to Berkeley and asked for Cockcroft and Walton's results to be verified. It took the team until September to do so, mainly due to lack of adequate detection apparatus.{{sfn|Heilbron|Seidel|1989|pp=137–141}}

Although important discoveries continued to elude Lawrence's [[Lawrence Berkeley National Laboratory|Radiation Laboratory]], mainly due to its focus on the development of the cyclotron rather than its scientific use, through his increasingly larger machines, Lawrence was able to provide crucial equipment needed for experiments in [[Particle physics|high energy physics]]. Around this device, he built what became the world's foremost laboratory for the new field of nuclear physics research in the 1930s. He received a [[patent]] for the cyclotron in 1934,<ref>{{US patent reference
 | number = 1948384
 | y = 1934
 | m = 02
 | d = 20
 | inventor = Ernest O. Lawrence
 | title = [https://patents.google.com/patent/US1948384 Method and apparatus for the acceleration of ions]
}}</ref> which he assigned to the [[Research Corporation]],{{sfn|Heilbron|Seidel|1989|pp=192–193}} a [[Private foundation (United States)|private foundation]] that funded much of Lawrence's early work.{{sfn|Heilbron|Seidel|1989|pp=27–28}}

In February 1936, [[Harvard University]]'s president, [[James B. Conant]], made attractive offers to Lawrence and Oppenheimer.{{sfn|Childs|1968|pp=235–237}} The University of California's president, [[Robert Gordon Sproul]], responded by improving conditions. The Radiation Laboratory became an official department of the University of California on July 1, 1936, with Lawrence formally appointed its director, with a full-time assistant director, and the university agreed to make $20,000 a year available for its research activities ({{Inflation|US-GDP|20000|1936|r=-4|fmt=eq}}).{{sfn|Childs|1968|pp=240–241, 248}} Lawrence employed a simple business model: "He staffed his laboratory with graduate students and junior faculty of the physics department, with fresh Ph.D.s willing to work for anything, and with fellowship holders and wealthy guests able to serve for nothing."<ref>{{cite web |url=http://www2.lbl.gov/Science-Articles/Research-Review/Magazine/1981/ |title=Lawrence and His Laboratory – A historian's view of the Lawrence years – Chapter 1: A New Lab for a New Science |first1=J. L. |last1=Heilbron|first2=Robert W. |last2=Seidel|last3=Wheaton|first3=Bruce R. |publisher=Lawrence Berkeley National Laboratory|year=1981|access-date=October 5, 2013}}</ref>

=== Reception ===
Using the new 27-inch cyclotron, the team at Berkeley discovered that every element that they bombarded with recently discovered [[deuterium]] emitted energy, and in the same range. They, therefore, postulated the existence of a new and hitherto unknown particle that was a possible source of limitless energy.{{sfn|Heilbron|Seidel|1989|pp=153–157}} [[William Laurence]] of ''[[The New York Times]]'' described Lawrence as "a new miracle worker of science".{{sfn|Heilbron|Seidel|1989|p=156}} At Cockcroft's invitation, Lawrence attended the 1933 [[Solvay Conference]] in Belgium. This was a regular gathering of the world's top physicists. Nearly all were from Europe, but occasionally an outstanding American scientist like [[Robert A. Millikan]] or [[Arthur Compton]] would be invited to attend. Lawrence was asked to give a presentation on the cyclotron.{{sfn|Childs|1968|pp=197–208}} Lawrence's claims of limitless energy met a very different reception in Solvay. He ran into withering skepticism from the Cavendish Laboratory's [[James Chadwick]], the physicist who had discovered the [[neutron]] in 1932, for which he was awarded the Nobel Prize in 1935. In a British accent that sounded condescending to Lawrence's ears, Chadwick suggested that what Lawrence's team was observing was contamination of their apparatus.{{sfn|Herken|2002|pp=9–10}}

[[File:60-inch cyclotron, c 1930s. This shows the (9660569583).jpg|thumb|left|The {{convert|60|in|m|2|adj=on}} cyclotron soon after completion in 1939. The key figures in its development and use are shown, standing, left to right: [[Donald Cooksey]], [[Dale R. Corson]], Ernest Lawrence, [[Robert Lyster Thornton|Robert L. Thornton]], [[John Backus (acoustician)|John Backus]], and [[Winfield Salisbury]]. In the background are [[Luis Walter Alvarez|Luis Alvarez]] and [[Edwin McMillan]].|alt=Six men in suits and ties stand in front of gigantic machinery. Two more are sitting on top of it.]]
When he returned to Berkeley, Lawrence mobilized his team to go painstakingly over the results to gather enough evidence to convince Chadwick. Meanwhile, at the Cavendish laboratory, Rutherford and [[Mark Oliphant]] found that deuterium [[Nuclear fusion|fuses]] to form [[helium-3]], which causes the effect that the cyclotroneers had observed. Not only was Chadwick correct in that they had been observing contamination, but they had overlooked yet another important discovery, that of nuclear fusion.{{sfn|Heilbron|Seidel|1989|pp=169–171}} Lawrence's response was to press on with the creation of still larger cyclotrons. The 27-inch cyclotron was superseded by a 37-inch cyclotron in June 1937,{{sfn|Heilbron|Seidel|1989|p=277}} which in turn was superseded by a 60-inch cyclotron in May 1939. It was used to bombard iron and produced its first radioactive isotopes in June.{{sfn|Childs|1968|p=288}}

As it was easier to raise money for medical purposes, particularly cancer treatment, than for nuclear physics, Lawrence encouraged the use of the cyclotron for medical research. Working with his brother John and Israel Lyon Chaikoff from the University of California's physiology department, Lawrence supported research into the use of radioactive isotopes for therapeutic purposes. [[Phosphorus-32]] was easily produced in the cyclotron, and John used it to cure a woman afflicted with [[polycythemia vera]], a blood disease. John used phosphorus-32 created in the 37-inch cyclotron in 1938 in tests on mice with [[leukemia]]. He found that the radioactive phosphorus concentrated in the fast-growing cancer cells. This then led to clinical trials on human patients. A 1948 evaluation of the therapy showed that remissions occurred under certain circumstances.{{sfn|Heilbron|Seidel|1989|pp=399–404}} Lawrence also had hoped for the medical use of neutrons. The first cancer patient received [[neutron therapy]] from the 60-inch cyclotron on November 20.{{sfn|Childs|1968|p=288}} Chaikoff conducted trials on the use of radioactive isotopes as [[radioactive tracer]]s to explore the mechanism of biochemical reactions.{{sfn|Heilbron|Seidel|1989|pp=405–414}}

[[File:University of California Radiation Laboratory staff on the magnet yoke for the 60-inch cyclotron, 1938.jpg|thumb|280px|University of California Radiation Laboratory staff framed by the magnet for the 60-inch cyclotron, 1938; Nobel prize winners Ernest Lawrence, [[Edwin McMillan]], and [[Luis Walter Alvarez|Luis Alvarez]] are shown, in addition to [[J. Robert Oppenheimer]] and [[Robert R. Wilson]].]]

Lawrence was awarded the [[Nobel Prize in Physics]] in November 1939 "for the invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements".<ref>{{cite web |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1939/ |title=The Nobel Prize in Physics 1939 |access-date=August 25, 2013 |publisher=The Nobel Foundation }}</ref> He was the first at Berkeley as well as the first South Dakotan to become a Nobel Laureate, and the first to be so honored while at a state-supported university. The Nobel award ceremony was held on February 29, 1940, in [[Berkeley, California]], due to [[World War II]], in the auditorium of [[Wheeler Hall]] on the campus of the university. Lawrence received his medal from Carl E. Wallerstedt, [[Sweden]]'s [[Consul General]] in [[San Francisco]].{{sfn|Childs|1968|pp=294–296}} [[Robert W. Wood]] wrote to Lawrence and presciently noted "As you are laying the foundations for the cataclysmic explosion of uranium ... I'm sure old Nobel would approve."{{sfn|Herken|2002|p=27}}

In March 1940, [[Arthur Compton]], [[Vannevar Bush]], [[James B. Conant]], [[Karl T. Compton]], and [[Alfred Lee Loomis]] traveled to Berkeley to discuss Lawrence's proposal for a 184-inch cyclotron with a 4,500-ton magnet that was estimated to cost $2.65 million ({{Inflation|US-GDP|2650000|1940|r=-6|fmt=eq}}). The [[Rockefeller Foundation]] provided $1.15 million to get the project started.{{sfn|Childs|1968|p=299}}