University of California Cyclotrons

The University of California cyclotrons were major features in Sam Ruben s education and in his research at Berkeley. In 1928 at age twenty-seven, Ernest Orlando Lawrence left Yale University for the University of California at Berkeley to become an Associate Professor of Physics, and at age twenty-nine he was promoted to Full Professor. Also in 1928, Robert Oppenheimer joined the physics department at Berkeley as an assistant professor. By that time, a great deal was known about the structure of atoms there is an extremely small dense central nucleus and a diffuse cloud of electrons distributed about the nucleus. Physicists, then, were strongly interested in developing methods to explore the nature of the nucleus, especially at Cambridge, England, but also at top physics departments in other European countries and 

Over the years, Lawrence went repeatedly to President Robert Sproul with a lucrative outside offer in his hand, and said that if the University of California did not match the oflFer by raising funds to build the next large cyclotron, Lawrence would be forced to leave. Sproul raised large sums of money for this purpose. The succession of cyclotrons at Berkeley is given by this chart  

On November 9, 1939, Ernest O. Lawrence received word that he had been awarded the Nobel Prize in Physics, but because of the war, it would not be possible for Lawrence to go to Sweden to accept the award. 

Sam Ruben s long-term partner, Martin Kamen wrote the following  

On February 29, 1940, there was a momentous ceremony in Wheeler Hall, where the Swedish Consul presented the Nobel Prize to E. O. L. .. 

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Electromagnetic separators, really large-scale mass spectrometers, called Calutrons because of their early development at the University of California Cyclotron Laboratory, were originally constructed for the Manhattan District during the second world war in order to separate in kilogram quantities. At the height... 

Calutrons are electromagnetic isotope separators that operate like analytical mass spectrometers. The term calutron is a tribute to the work of E. O. Lawrence and his team of scientists who developed the process at their University of California cyclotron laboratory and assisted in its transformation to a production-scale process at the electromagnetic plant located at the Y-12 site in Oak Ridge, Tennessee. The Y-12 calutron process was replaced shortly after the end of World War II by the gaseous diffusion process located at the K-25 plant (also in Oak Ridge). The gaseous diffusion operation had much larger production capabilities and was far less labor intensive. 

The roots of the LBNL can be traced back to the 1920s, and the pursuit of the secrets of the nucleus. Ernest O. Lawi ence, built the first large cyclotron (a particle accelerator) on the Berkeley campus of the University of California in 1931. Unlike most the other labs, LBNL s beginnings depended on the support of philanthropists who saw the promise in Lawrence s work. Seeking private sector support, an... 

We solved the first problem by bombarding large amounts of uranyl nitrate with neutrons at the cyclotrons at the University of California and Washington University plutonium concentrates were derived from these sources through the efforts of teams of chemists who used ether extractions to separate the bulk of the uranium and an oxidation-reduction cycle with rare earth fluoride carrier to concentrate the product. I managed to convince chemists trained in the techniques of ultramicrochemistry to join us to solve the second problem—Burris B. Cunningham and Louis B. Werner of the University of California and Michael Cefola from New York University. 

As mentioned above, early tracer work at the University of California in 1941 had established the existence of a lower oxidation state (IV and/or III state) and a higher state (VI and/or higher state), and the ultramicrochemical work late in 1942 and in 1943 had defined the existence of the IV and VI states. The III oxidation state was discovered early in 1944 by Connick and coworkers (1949), who actually worked with about 0.25 milligram of cyclotron-produced plutonium, at the University of California,... 

In anticipation of the development to operational status of the ion or direct counting systems, it would be helpful if we could compare these values with projected counting errors for the two types of direct counting systems being developed. Table 4 lists projections for the Rochester Van de Graaff facility [49] and the University of California Lawrence Berkeley cyclotron system employing an external ion source [31,50]. Table 4 also lists the sample sizes and approximate measurement periods for both systems. This data illustrates the potential extention in dating... 

Lawrencium - the atomic number is 103 and the chemical symbol is Lr. The original chemical symbol was proposed as Lw but it was changed because W is an unusual occurrence in many languages and it is a cumbersome spoken word. The name derives from the American physicist Ernest O. Lawrence , who developed the cyclotron. Credit for the first synthesis of this element in 1971 is given jointly to American chemists from the University of California laboratory in Berkeley, California under Albert Ghiorso and the Russian scientific team at the JINR (Joint Institute for Nuclear Reactions) lab in Dubna, Russia under Georgi N. Flerov, after a series of preliminary papers presented over a decade. The longest half-life associated with this unstable element is 3.6 hour Lr. 

Albert Ghiorso and his team of chemists that included Glenn T. Seaborg, Stanley G. Thompson, Bernard G. Harvey, and Gregory R. Ghoppin bombarded atoms of einsteinium-253 with hehum ions in the cyclotron at the University of California at Berkeley. This resulted in a few atoms of mendelevium-256, which is one of the isotopes of mendelevium plus a free neutron. 

Experimental studies soon confirmed all these expectations. The most powerful tool in achieving these results was the cyclotron. Ernest O. Lawrence, its inventor, was born in Canton, South Dakota, on August 8, 1901. He was educated at St. Olaf College and the University of South Dakota, and did graduate work in physics at Minnesota, Chicago, and Yale. The latter university gave him his doctorate in 1925. He remained at Yale until 1928, and was then called to the University of California at Berkeley, where he still remains as Director of the Radiation Laboratory. He received the Nobel Prize in Physics in 1939. It was due to Lawrence and the cyclotron that California became the outstanding center for the synthesis of new elements, which it still remains (I). 

LAWRENCE, ERNEST O. (1901-1958). An American physicist who invented the cyclotron in 1929. Both the element lawrenciuni and the Lawrence Livermore Research Laboratory at the University of California were named alter him. 

A physicist works with a small cyclotron at the University of California at Berkeley. 

The radioactive carbon used in these studies was carbon-11, abbreviated as which was prepared by bombarding boric oxide in the 70 centimeter cyclotron. Carbon-11 has a half life of twenty minutes, which means that one half of it remains after twenty minutes, one quarter remains after forty minutes, one eighth remains after one hour, one part in sixty four remains after two hours. An experiment using carbon-11 needs to be completed within a small number of hours. A book by Martin D. Kamen Radiant Science, Dark Politics, A Memoir of the Nuclear A e, University of California Press, Berkeley and Los Angeles, California, 1985] gives this account of working in the laboratory with the fast decaying carbon-11. 

In 1940, three chemists working at the University of California at Berkeley found evidence of element 85. Dale R. Corson, Kenneth R. Mackenzie, and Emilio Segre (1905-1989) found evidence of element 85 at the end of an experiment they were conducting with a cyclotron. A cyclotton is a particle accelerator, or atom smasher. In a cyclotron, small particles, such as protons, are made to travel at high speeds. The particles collide with atoms, causing the atoms to break apart into other elements. 

Named after Dimitri Mendeleev, mendelevium was first synthesized in 1955 by the team of Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley G. Thompson, and Glenn T. Seaborg. They used the 60-inch cyclotron at the Berkeley Laboratory of the University of California to bombard einsteinium with helium ions. Only enough atoms of mendelevium have been made to confirm its identity. 

He attended the University of California at Berkeley as a national research fellow working in the field of molecular beams, in particular the measurement of the magnetic moment of the proton by a molecular beam method. He became a member of the team at the radiation laboratory under Professor E.O. Lawrence, studying nuclear reactions and their products and helping design and construct cyclotrons. 

The fast-moving helium nuclei were supplied by the old, 60-inch cyclotron on the Berkeley campus of the University of California. 

Lawrence Berkeley Laboratory University of California One Cyclotron Road Berkeley, CA 9994720 Phone (510) 486-4000... 

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