Berkeley 88-Inch Cyclotron

A renewed interest in studying the chemical properties of the transactinide elements in more detail both experimentally and theoretically arose in the late 1980s, see [18-26] for recent reviews. A series of manually performed separations of 261Rf in aqueous solutions was performed by the Berkeley group at the Berkeley 88-Inch Cyclotron [2-6,27], Their experiments involving liquid-liquid extractions typically comprised the following steps ... 

Studies of the dubnium behavior. 930 experiments were conducted with 262Db produced at the Berkeley 88-Inch Cyclotron in the 249Bk(lsO,5n) reaction. Extractions were performed in the Aliquat336/Cl - HC1 system with a 50 s cyclic collection time of the KC1 aerosol on a Kel-F slider in ARCA II. The reaction products were fed onto the column in 10 M HC1 followed by the elution of a Ta fraction in 6 M HC1 and a Nb,Pa fraction in 6 M HNO3/O.OI5 M HF. The effluents were continuously sprayed through a 60 pm nozzle onto hot Ta discs on which they were evaporated to dryness by hot He gas and infrared light. Start of measurement of the activities was 60 s (Ta fraction) and 76 s (Nb, Pa fraction) after the end of collection, respectively. 

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. 

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. 

Production of Sr-82. An important consideration in the development of radioisotope generators is the availability, cost, and radionuclidic purity of the long-lived parent. In the case of Sr-82, the 25 day radionuclide is needed in 100-200 mCi amounts in order to provide adequate elution yields of Rb-82 from one loading of Sr-82 every three months. Initially the Sr-82 for the generator was produced at the Lawrence Berkeley Laboratory (LBL) 88-inch cyclotron by the Rb-85 (p,4n) Sr-82 nuclear reaction (12). However, because of the long irradiation time required to produce... 

Lawrence Berkeley Laboratory 88-Inch Cyclotron for an integrated beam of 2.1... 

Named after the planet Pluto, which is named after the Greek god Plouton, the ruler of the underworld, plutonium was first produced in 1940 by the team of Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy, and Arthur C. Wahl. They used the 60-inch cyclotron at Berkeley, California, to bombard... 

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. 

The Berkeley "Rad Lab," where most of the synthetic elements have been produced or identified, is one of the laboratories responsible for this new phase in man s relationship to nature. Its principal tools are the particle accelerators like the bevatron in the foreground and the 184-inch cyclotron above it, all of them involved in fundamental research for the Atomic Energy Commission. 

In Palermo they had a very poor and small laboratory, nothing like the large laboratories around Berkeley, and I wanted to find some research to do. During the summer of 1936 I had been in Berkeley to visit the 37-inch cyclotron, the little cyclotron we aren t using any more. The cyclotron was used to accelerate deuterons, and I took some pieces of it—which were made of molybdenum and had been exposed to deuterons —back to Palermo with me. 

The work on element 94 was continued by Glenn T. Sea-borg, Arthur C. Wahl, Joseph W. Kennedy, and Emilio Segre. Actually, the first positive identification of any isotope of the new element was made by bombarding uranium in the Berkeley 60-inch cyclotron with deuterons—hydrogen nuclei each containing a neutron as well as a proton—rather than with simple neutrons. 

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

The first study of the solution chemistry of Rf was performed at Berkeley in 1970 and showed that Rf had a stable tetravalent state with properties similar to the gronp-4 elements Zr and Hf and different from Lr and the other trivalent actinides. This established that Rf shonld be placed in the Periodic Table as the heaviest member of group 4 and the first member of a new 6d transition series. It also confirmed the 1945 prediction of Seaborg that the actinide series should end with element 103. The first studies of the solution chemistry of element 105, condncted at the 88-Inch Cyclotron at Berkeley, were reported in 1988 and showed that the element behaved similarly to the group-5 elements Nb and Ta in its sorption properties, bnt differently from the group-4 elements. However, in extractions into certain organic solvents, Db(Ha) and Ta extracted but Nb did not, creating a renaissance of interest in more detailed studies of the behavior of element 105. 

Californium — (State and University of California), Cf at. wt. (251) m.p. 900°C sp. gr. 15.1 at. no. 98. Californium, the sixth transuranium element to be discovered, was produced by Thompson, Street, Ghioirso, and Seaborg in 1950 by bombarding microgram quantities of Cm with 35 MeV helium ions in the Berkeley 60-inch cyclotron. Californium (111) is the only ion stable in aqueous solutions, all attempts to reduce or oxidize californium (111) having failed. The isotope Cf results from the beta decay of Bk while the heavier isotopes are produced by intense neutron irradiation by the reactions ... 

Mendelevium — (Dmitri Mendeleev [1834-1907]), Md at. wt. (258) at. no. 101 m.p. 827°C valence +2, +3. Mendelevium, the ninth transuranium element of the actinide series to be discovered, was first identified by Ghiorso, Harvey, Choppin, Thompson, and Seaborg early in 1955 as a result of the bombardment of the isotope Es with helium ions in the Berkeley 60-inch cyclotron. The isotope produced was Md, which has a half-life of 78 min. This first identification was notable in that Md was synthesized on a one-atom-at-a-time basis. Nineteen isotopes and isomers are now recognized. Md has a half-life of 51.5 days. This isotope has been produced by the bombardment of an isotope of einsteinium with ions of helium. It now appears possible that eventually enough Md can be made so that some of its physical properties can be determined. Md has been used to elucidate some of the chemical properties of mendelevium in aqueous solution. Experiments seem to show that the element possesses a moderately stable dipositive (II) oxidation state in addition to the tripositive (III) oxidation state, which is characteristic of actinide elements. 

In the 1960s, we proposed to the NIH that we reactivate a 60-inch cyclotron built in 1939 by Merle Tuve at the Carnegie Institute of Washington. It was identical to the 60-inch cyclotron built by Ernest Lawrence in Berkeley, CA. 

The developments in nuclear chemistry during the 1930s, the observation of nuclear fission in 1938, and the urgency of the Manhattan Project will launch this discipline into a decade of breakthroughs. Uranium 235, rather than its more abundant isotope U-238, is rapidly fissionable by neutrons. In 1941, Glenn Seaborg and coworkers discovered that tbeir newly discovered element, plutonium (specifically Pu-239), has fission properties comparable to U-235. The Berkeley 60-inch cyclotron, employed between the years 1939 and 1941, is displayed in the accompa-... 

The 60-inch cyclotron group at Berkeley Donald Cooksey, Dale R. Corson, Ernest O. Lawrence, Robert L. Thornton, John Backus, Winfield W. ( W. W ) Salisbury, Luis W Alvarez, and Edwin M. McMillan, 1939 (Lawrence Berkeley National Laboratory)... 

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