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Both acid and alkaline dissolutions of Be/sub 3/N/sub 2/ were carried The recommended alkaline dissolution procedure is outlined. (M.H.R.)

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This report addresses the dissolution of uranium tetrafluoride.

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The object of this project is to reduce the impurities and raise the density of rejected slugs and briquetted turnings from these slugs by recasting the material. Summary and conclusions are (1) slugs and briquettes made from turnings produced when these slugs were machined can be recast with great improvement in quality; (2) casting this material is quite hard on graphite crucibles, but a long-range program might point the way to better graphite usage; (3) this metal run alone gives fair yields (88.8% to 94.8%) if heated to 2500 F and then cooled to 2400 F before pouring. Mixing with virgin metal improves the final quality, but does not materially increase the yield; (4) briquettes should not be mixed with magnesium before recasting.

This summary discusses the following topics: (1) 184-inch cyclotron program; (2) a 60-inch cyclotron program; (3) synchrotron program; (4) Linear accelerator program; (5) Experimental physics, experiments with the 184-inch cyclotron, fast neutron scattering, and neutron-proton scattering; (6) Theoretical physics; and (7) isotope research program.

The year 1947 has witnessed the dawn of a new era of atomic science, a flowering of fundamental knowledge of the nature of matter which appears to be unsurpassed even by that period of the 1930's which led to the age of plutonium. A great new cyclotron, an atom-smasher ten times more powerful than the one which brought plutonium into the world, has carried mankind over a new horizon of sub-atomic space. It has brought scientists at last to grips with the infinitely small and rapid forces, until now beyond reach, which operate within the incredibly tiny distances of nuclear space. On the new energy frontier created by the giant machine, now laws govern nuclear reactions. methods are at hand, heretofore unavailable, which permit the measurement and determination of the nature of sub-atomic forces. Under ultra-high energy bombardment, the nucleus presents a different appearance from the nucleus of Bohr and Rutherford, the nucleus of atomic energy fission. The new exploration of the atom has been sponsored by the Atomic Energy Commission with the giant, new 4000-ton cyclotron in the Radiation Laboratory of the University of California. This is the thirdmajor machine built by the Director of the Laboratory and inventor …

The excitation curve for the reaction C{sup 12}(n,2n)C{sup 11} has been calculated for energies up to 100 Mev. The calculations were done as described in the preceding letter for the similar reaction of C{sup 12} under proton bombardment. The results of the calculations for 50% charge exchange are shown in Figure 1. The calculated cross section for the reaction at 90 Mev is: .011 barns for 100% charge exchange and .013 barns for 50% charge exchange. The experimental value is 0.025 {+-} .004 barns. The ratio of the cross section of the reaction C{sup 12}(pnpn)C{sup 11} to the cross section of the above reaction at 90 Mev is 5.8 for 100% charge exchange and 3.8 for 50% charge exchange. The experimental ratio is 2.7 at 90 Mev. This difference in cross sections between the two reactions is established by two factors. Firstly, there is the part played by charge exchange in the C{sup 12}(pnpn)C{sup 11} reaction which leads to excited N{sup 12} with the subsequent boiling off of a proton, while a similar exchange process cannot take place for the C{sup 12}(n2n)C{sup 11} reaction. Secondly, there is the difference between the contributions of the knock out process as a result …

A 1,000 Mev synchrotron is under construction. The magnet will be a ring magnet containing about 900 tons of steel. The plates are of 1.2 inch steel with a 0.1 percent carbon content. A diagram of the cross section of this magnet is given in Figure 1. The design of the vacuum chmnber presents some difficulties since the space behind the gap is not large enough to permit easy access to the windings and to the vacuum space behind the gap. The field strength at the gap is 15,000 gauss with a 1 sec. rise time. A d.c. generator of 1,000 v and 10,000 amps and a flywheel will be used to energize the magnet and store the energy. Plans for the vacuum system are not complete, but probably a porcelain system will be used. This will reduce the gap quite considerably. It is planned to inject at 3,000 volts. The energy added to be about 200 ev per revolution. The frequency range is 250 kc/sec to 10 mc/sec; the power required is 10 Kw. A diagrammatic view of the electrical arrangement of the r.f. system is given.The variable inductance is a coil tipped at variable pitch into a pool …

All errors due to diffraction effects in a neutron attenuation experiment are computed. Also a special experiment to measure the forward intensity of diffracted neutrons from lead and copper is described, and the results given. These agree with the theoretical values.

Prior analyses of a plasma in a magnetic field have been limited, as far as the writer is aware, to cases in which the relative change in field over the orbital distance and the relative change in ion concentration are both small, or in which the relations have been viewed in a purely hydrodynamical way. The first approach excludes cases which can be of considerable interest, for it fails for a plasma edge. The second loses all sight of the structure imposed by the orbital motions.