Two new positron active isotopes, B{sup 8} and Na{sup 20}, have been found to decay to excited states of Be{sup 8} and Ne{sup 20}, which in turn decay 'instantaneously' by alpha emission. Their half-lives are 0.65 {+-} 0.1 sec. and 1/4 sec. respectively. N{sup 12} is also found to have a low energy positron group which leads to an {alpha}-unstable excited state in C{sup 12}. The masses of B{sup 8} and Na{sup 20} are 8.027 and 20.015 respectively. B{sup 8} decays by a 13.7 {+-} 0.3 Mev positron, through the same excited state of Be{sup 8} as does Li{sup 8}. Estimates of the energies of the excited state in C{sup 12} and Ne{sup 20} are made.

The fission reaction has been observed with high energy accelerator projectiles for elements as light as tantalum but has not been reported for medium weight elements. The present note presents evidence for the occurrence of reactions which are probably most properly described by the term 'fission' and which seem to occur with very small yield throughout the region where this type of reaction is only slightly exoergic or even endoergic with respect to mass balance. In the course of detailed investigation of the spallation of copper and the variation of the product yields with energy of the bombarding particle the threshold for formation of radioactive Cl{sup 38} (38-minute half-life) from elemental studied. The energetically most economical way in which Cl{sup 38} might be spallation reactions is by emission from the bombarded copper nucleus of nucleons in groups such as alpha-particles instead of single nucleons 0 The energetic requirements for the reaction Cu{sup 63}(p,pn6a)Cl{sup 38}, in which the maximum number of alpha-particles are emitted, include (1) the mass difference between the reactants and the products and (2) the excitation energy which the alpha-particles must have in order to pass over the coulombic barrier, Since the reaction is endoergic with respect to …

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The lifetime for the decay of a {pi} meson into {mu} meson and neutral particle was first measured by Richardson and later by Martinelli and Panofsky. The method was the same in both cases: The fraction of {pi} mesons surviving various times of flight is measured by placing photographic detectors at various path lengths from the target. In the experiment reported here we observe the time lag between the two bursts of fluorescence due to mesons decaying in a scintillation crystal. The first burst is due to the stopping of the entering {pi} meson, the second to the {mu}-meson. As is shown in Fig. 1, a particle penetrating the first and into the second crystal starts the sweep (10{sup -8} sec/mm) of an oscilloscope. The pulses in the second crystal are delayed 0.5 x 10{sup -6} sec to allow the sweep to start and brighten and are then photographed. If the responsible particle is a {pi}{sup +} meson which stops in the crystal, it undergoes {pi}-{mu} decay and two pulses appear on the trace. The {mu}{sup +} meson has a range of only 2 mm in the crystal. If its decay electron is detected some time (.5-2.5 x 10{sup -6} …

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The Metal Conversion Process described herein is designed to handle the combined output of decontaminated uranium from both the Redox and T.B.P. processes. Thus the design rate is 13-1/8 short tons per day. The bulk of the equipment is to be installed in the presently unused 224-U Building. The feed storage tanks, the gas absorber and gas cooler will be outside but adjacent to this building. The process has been divided into two steps: acid recovery and uranyl nitrate concentration; and uranyl nitrate conversion. The major items of equipment and flows thru the plant are shown on Engineers` Flow Sketches, numbered SK-2-50005, and Sk-2-50006.

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This report, from the 300 area of the Hanford Plant, May 31, 1956, describes problems and operation of a vacuum system and associated equipment.

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A comprehensive survey of the literature was made in an effort to identify nonmetallic materials of possible usefulness as liquid coolants. Materials having maximum melting points of 1000 deg F and boiling points of l200 deg F were considered, but boiling points above 2200 deg F were preferred. Melting points, boiling points, densities, heat capacities, and thermal conductivities were tabulated. Approximately 190 materials appeared to have melting and boiling temperatures in a suitable range. A paucity of thermal- conductivty and heat-capacity data prevented further estimates of suitability of all but nine of these materials. Of these nine nonmetallics, only sodium hydroxide appeared to offer possibilities when considered according to the NEPA formula. (M.C.G.)

A method has been adapted from ion exchange studies for removal of the fission products, Cs-137, Sr-90, and the rare earths for both untreated urine samples and the supernates from the precipitation steps in the TTA procedure for plutonium. Because of the excessive amount of eluant necessary to separate the fission products and the resulting time required to run a separation, a method was developed to remove the Sr-Y, Ce and Pr by chemical means and Cs from the raffinate of this extraction by ion exchange. It should be noted that Cs is easily separated from Pu in the separations plant, and that is presence as a contaminate in the outer areas is not as probable as the other long-lived fission products. This fact has been born out in three years of analyzing contaminated samples from the 200 Area by the H.I. Development Divisions.

The objective of this project was to remove impurities in the form of PbO/sub 2/ from a HNO/sub 3/ solution by electrolysis. This electrolytic cell must process up to a 15-gal. batch in a minimum of time. It is desirable that the impurity remaining after processing be less than 20 ppm. Construction and operation of the cell are described. (G.Y.)

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