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New Hot Laboratory Facilities which support three major research programs directed by the Los Alamos Scientific Laboratory of the University of California are described. For the Nuclear Rocket Propulsion Program, a hot cell addition to the Radio Chemistry Building at Los Alamos will be completed early in 1963, and construction is expected to start soon on the hot cell addition to the Maintenance, Assembly and Disassembly Building at the Nuclear Rocket Development Station in Nevada. Integral hot laboratories are designed in the facilities for the Ultra High Temperature Reactor Experiment and the Fast Reactor Core Test at Los Alamos. (auth)

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The bremsstrahlung emitted by an electron scattered in a Coulomb field was first calculated by Bethe and Heitler. The total cross section for production of photons with wave number between k and k + dk by a nonrelativistic electron of kinetic energy {epsilon} is d{sigma}/dk dk = 16/3 Z{sup 2}r{sub 0}{sup 2} (e{sup 2}/hc) (mc{sup 2}/{epsilon})log ({radical} {epsilon}/hck + {radical} {epsilon}/hck -1) dk/k, where Ze is the charge of the (heavy) ion, and r{sub 0} is the classical electron radius. Bremsstrahlung in a plasma has been computed by a number of authors in the approximation of replacing the Coulomb field by a cut-off Coulomb or static Debye potential. It is the purpose of this communication to call attention to another important effect of the medium upon the rate of emission of bremsstrahlung. This may be described as a modification of the relation of the photon's energy to its wave number, due to the index of refraction of the medium. Equivalently, we note that one must include in the calculation of bremsstrahlung in a medium the photon-medium interactions which result in the 'clothing' of a 'bare' photon. The replacement of a particle by a quasiparticle has long been known to be …

The second-order nonlinear differential equation for the rotation of Mercury is shown to imply locked-in motion when the period is within the range (2T/3) [1-{lambda} cos 2{pi}t/T {+-} 2/3 (21{lambda}e/2){sup 1/2}], where e is the eccentricity and T the period of Mercury's orbit, the time t is measured from perihelion, and {lambda} = (B-A)/C measures the planet's distortion. For values near 2T/3, the instantaneous period oscillates about 2T/3 with period (21{lambda}e/2){sup -1/2}T.

Present knowledge of United States tar sands, including physical properties, occurrence, reserves, and recovery methods, is reviewed and evaluated. Tar sands are oil-, bitumen-, asphalt-, tar-, or petroleum-impregnated rock from which little hydrocarbon material is recoverable by conventional crude oil production techniques. Tar sand oil has been produced by steam injection and underground combustion techniques and by mining methods. However, efficient application of nonmining recovery techniques is hindered because of difficulties in establishing and maintaining formation permeability. Mining and processing methods being used in or proposed for Canadian commercial operations are also discussed.

The constitution of the plutonium-copper binary alloy as determined by differential thermal analysis is presented. The system is characterized by two congruent melting compounds, PuCu2 (m.p. 865 degrees C.) and Pu4Cu17 (m.p. 954 degrees C.); two incongruent melting compounds, PuCu4 (m.p. 906 degrees C.) and Pu2Cu11 (m.p. 926 degrees C.); three eutectics, 96 atom per cent copper (m.p. 626 degrees), 70.5 atom per cent copper (m.p. 849 degrees C.), and 91 atom per cent copper (m.p. 881 degrees C.); and two peritectics at 75 atom per cent (m.p. 906 degrees C.) and 85.5 atom per cent (m.p. 926 degrees C.). Solid solution was found above 97 atom per cent plutonium. The apparatus, the method of investigation, and the binary alloy phase diagram is discussed.

From American Nuclear Society Meeting, New York, Nov. 1963. In computer-coupled automated activation analysis such as in the Mark II system, conventional methods of data readout impose a serious restriction on the minimum handling time per sample. A data coupler for operating between the data accumulation system and the computer tape unit was developed which contributes nothing to the handling time per sample, does not distort the data, and prepares the data for direct computer entry. In addition to activation analysis, the coupler may be used to obtain successive spectra separated in time by 0.16 sec in the study of short-lived isotopes. (D.L.C.)

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The labeling of newly-formed lymph cells with tritiated thymidine, lymphatic duct cannulation, and the peripheral destruction of lymphocytes by extracorporeal irradiation of the blood were used to estimate the mass of prestored lymphocytes and the relative degree of recirculation of 1ymphocytes from blood to lymph and back again. Topics discussed include the effects of extiacorporeal irradiation on the histologic picture of the lymphoreticular tissue, the influence of extracorporeal irradiation upon the thoracic duct output, and preliminary observations on labeling of lymphocytes by tritiated thymidine at the completion of extracorporeal irradiation. Data indicate that the mass of preformed small lymphocytes may be as large as 40 times that present in peripheral blood, that the blood feeds lymphocytes primarily into the lymph, and presents strong evidence for lymphocyte recycling. (C.H.)

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MAMMALIA. Radiation effects on, effects of dose rate on; RADIOBIOLOGY. Conference on effects of dose rate on radiosensitivity of mammals.

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The distribution of velocity vectors of reaction products is discussed with emphasis on the restrictions imposed by the conservation laws. The recoil velocity that carries the products away from the center of mass shows how the energy of reaction is divided between internal excitation and translation. Similarly, the angular distributions, as viewed from the center of mass, reflect the partitioning of the total angular momentum between angular momenta of individual molecules and orbital angular momentum associated with their relative motion. Crossed-beam studies of several reactions of the type M + RI yields R + MI are described, where M = K, Rb, Cs, and R = CH/sub 3/, C/sub 3/H/sub 5/, etc. The results show that most of the energy of reaction goes into internal excitation of the products and that the angular distribution is quite anisotropic, with most of the MI recoiling backward (and R forward) with respect to the incoming K beam. (auth)

Various mechanisms for the formation of point defects in ionic crystals are considered. Their probable importance as a function of the energy of the ionizing radiation and the temperature at which the irradiation takes place is discussed. Complex centers formed from aggregates of simple point defects are reviewed and their occurrence considered in terms of the expected spatial distribution of the point defects. The effect of high energy x rays and protons on the ionic conductivity is discussed in terms of a new interpretation of the conductivity curve as a function of temperature, and it is suggested that radiation-enhanced diffusion may be important in explaining the experimental data. (auth)

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A solenoid wound with high-field superconducting wire displays maximum currents and fields (H) that are less than the critical field of the wire itself in an equal field (H). Montgomery's and Chandraseknar and Hulm's models for these maximum properties indicate, respectively, a unique coil quenching characteristic for geometrically similar solenoids and one unique characteristic for all solenoids with identical wire type and turn distance. Experiments with Pb coils did not verify Montgomery's model and contradicted Chandrasekhar and Hulm's model. The experimental results, however, did support an analysis of the surface currents in an ideal superconducting infinitely long solenoid. (D.C.W.)