Cyclotron Berkeley

Gr. technetos, artificial) Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Eawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial material have been made. Finally in 1962, technetium-99 was isolated and identified in African pitchblende (a uranium rich ore) in extremely minute quantities as a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. 

Planet pluto) Plutonium was the second transuranium element of the actinide series to be discovered. The isotope 238pu was produced in 1940 by Seaborg, McMillan, Kennedy, and Wahl by deuteron bombardment of uranium in the 60-inch cyclotron at Berkeley, California. Plutonium also exists in trace quantities in naturally occurring uranium ores. It is formed in much the same manner as neptunium, by irradiation of natural uranium with the neutrons which are present. 

Dmitri Mendeleev) Mendelevium, the ninth transuranium element of the actinide series discovered, was first identified by Ghiorso, Harvey, Choppin, Thompson, and Seaborg in early in 1955 during the bombardment of the isotope 253Es with helium ions in the Berkeley 60-inch cyclotron. The isotope produced was 256Md, which has a half-life of 76 min. This first identification was notable in that 256Md was synthesized on a one-atom-at-a-time basis. 

E. O. Lawrence (Berkeley) invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements. 

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... 

Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA tdtilley berkeley.edu... 

Name named after its place of discovery, Berkeley, where Ernest 0. Lawrence built the first cyclotron and where most artificial elements were discovered... 

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... 

Cyclotron System (Berkeley) Source T. S. Mast, personal communication. 

Lawrence Berkeley National Laboratory Materials Science Department 1 Cyclotron Road MS 2-100 Berkeley, CA 94720-0001 USA... 

National Center for Electron Microscopy, Ernest Orlando Lawrence Berkeley National Laboratory, One Cyclotron Road, Bldg. 72, Berkeley CA 94720, USA... 

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. 

Glenn T. Seaborg and his colleagues, S. G. Thompson and A. Ghiorso continued to use the cyclotron in their laboratory located at the University of Galifornia, Berkeley, to create new transuranic elements. Between 1949 and 1950, they produced their fourth artificially... 

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. 

Three groups had roles in the discovery of nobelium. First, scientists at the Nobel Institute of Physics in Stockholm, Sweden, used a cyclotron to bombard Cu-244 with heavy carbon gC-13 (which is natural carbon-12 with one extra neutron). They reported that they produced an isotope of element 102 that had a half-life of 10 minutes. In 1958 the team at Lawrence Laboratory at Berkeley, which included Albert Ghiorso, Glenn Seaborg, John Walton, and Torbjorn Sikkeland, tried to duplicate this experiment and verify the results of the Nobel Institute but with no success. Instead, they used the Berkeley cyclotron to bombard cerium-... 

The first isotope of this element having mass number 253 and half-life 20 days was detected in 1952 in the Pacific in debris from the first thermonuclear explosion. The isotope was an alpha emitter of 6.6 MeV energy, chemically analogous to the rare earth element holmium. Isotope 246, having a half-life 7.3 minutes, was synthesized in the Lawrence Berkeley Laboratory cyclotron in 1954. The element was named Einsteinium in honor of Albert Einstein. Only microgram amounts have been synthesized. The element has high specific alpha activities. It may be used as a tracer in chemical studies. Commercial applications are few. 

The element first was made by Ghiorso, Harvey, Choppin, Thompson, and Seaborg in 1955 in Berkeley, California. It was synthesized by bombardment of einsteinium-253 with alpha particles of 41 MeV energy in a 60-inch cyclotron. The element was named Mendelevium in honor of Russian chemist Dimitri Mendeleev. Mendelevium —258 isotope with a half-life of 60 days was discovered in 1967. The element has no commercial use except in research to synthesize isotopes of other transuranium elements. 

Neptunium, the first transuranium element, was discovered hy E. M. McMdlan and P. H. Ahelson in 1940 in Berkeley, California. It was produced in the cyclotron in a nuclear reaction by bombarding uranium-238 with neutrons. An isotope of mass 239 and atomic number 93 and ti/2 of 2.4 days was produced in this reaction. Neptunium-237, the longest-lived alpha-emitter with half-life 2.14x10 years, was discovered two years later in 1942 by Wahl and Seaborg. The new element was named after the planet Neptune, the planet next to Uranus in the solar system. 

The first cyclotron was built by Ernest O. Lawrence in 1932, and since 1938, cyclotrons have been used for patient treatment. In Berkeley, in 1954, the first human target irradiated with protons was the pituitary gland with the aim to suppress its function for slowing down the metastatic development of breast cancer. 

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). 

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