Philips cyclotron

In the Rf experiments [35] performed at the PSI Philips Cyclotron, 261Rf was produced in the Cm O, 5n) reaction at 100 MeV. The target contained 10% Gd enriched in 152 Gd to produce simultaneously short-lived Hf isotopes that were used to monitor the behavior of Hf and to perform yield checks by Y spectroscopy. Rf and Hf were transported by a He(KCl) gas jet and were collected for 90s by impaction inside ARCA II [7]. The deposit was dissolved in 200 pL 0.1 M HNO3/X M HF (x variable) and was fed onto the 1.6x8 mm cation-exchange column at a flow rate of 1 mL min 1. The effluent was evaporated to dryness as sample 1. In order to elute remaining Rf and Hf from the column, a second fraction of 200 pL 0.1 M HNO3/O.I M HF was collected to strip all group-4 elements from the column. The fraction was prepared as sample 2. 

Several chemical systems were tested with the fission products 93Y,97 Zr, "Mo and W isotopes produced in the 20Ne + 152Gd reaction (Brtichle et al. 1992) at the PSI Philips cyclotron, or-hydroxyisobutyric acid solutions of 5 x 10-2 M, pH = 2.65 or pH = 5 used to elute W in a rapid, one-stage separation from cation exchange columns provided a good separation from Hf and Lu (Brtichle etal. 1992). Likewise (Brtichle et al. 1992), solutions with 0.1 M HC1 and various HF concentrations between 10 4 M and 10-2 M were eluting W rapidly while Hf was safely retained on the column below... 

With the reaction oven temperature kept at 900°C and typically 100 ml/min CI2 saturated with SOCI2 plus 2 ml/min O2, the chromatographic behavior ofshort-Hved Mo isotopes from fission and of short-lived W isotopes produced at the PSI Philips cyclotron in the Gd( Ne,xn) reaction was studied and values of of —90 kJ/mol were measured for... 

This was confirmed in an independent experiment in which Db was produced in the reaction " Bk( 0,4n) at the Philips Cyclotron of the Paul Schener Institute (PSI) Villigen, Switzerland. The products were collected for 15 min and then subjected to a chemical separation specific for group-4 elements. The product was dissolved in 0.5 M unbuffered a-HiB and eluted from a cation-exchange column. The effluent was made 9 M in HCl and group-4 tetrachlorides were extracted into TBP/Cyclohexane which was evaporated to dryness on a Ta disk. The Ta disks were assayed for a and SF spectrometry. A SF radioactivity with a half-life of 20 min was observed and again assigned to the nuclide Rf, confirming that it is formed by EC decay of Db with a decay branch of % [94]. 

Fermi s pile turned out to be a plant which efficiently manufactured a new element in large quantities. This element is plutonium. It is a brand new man-made chemical element which fissons just as easily as U-235. The story of the birth of this synthetic element goes back to a day in May, 1940, when two men using Lawrence s cyclotron at Berkeley, California, bombarded uranium with neutron bullets. The two men were Edwin M. McMillan and Philip H. Abelson. After the bombardment of U-238 they detected traces of a new element, heavier than uranium. This new element, No. 93, was named neptunium by McMillan. It was a very difficult element to study, for its life span was very short. It threw out neutrons immediately and in a split second was no longer neptunium. 

Philip N. Ross, Jr. (Primary Contact), Nenad Markovic Lawrence Berkeley National Laboratory Materials Sciences Division I Cyclotron Rd, MS 2-100 Berkeley, CA 94720... 

In 1940, Edwin M. McMillan (1907-91) and Philip H. Abelson (1913-2004), working in Berkeley, bombarded uranium with cyclotron-produced neutrons, producing element 93, neptunium (Np). Neptunium was the first transuranium element to be reported. It is one beyond uranium in atomic number, hence the name, after the planet Neptune which is the one beyond Uranus. In the same year Glenn T. Seaborg (1912-99) and others in the Berkeley group discovered element 94, plutonium (Pu). Its potential for nuclear fission was soon apparent and the discovery was only... 

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