The Livermore 90 deg inch variable-energy cyclotron was used to measure the 90 deg excitation function for the Al/sup 27/(p, gamma )Si/sup 28/ reaction. Proton energies between 5 and 13 Mev were used which gave excitation energies in Si/sup 28/ corresponding to the region of the photonuclear giant resonance. Two gamma rays were observed: gamma /sub O/, the groundstate gamma ray and gamma / sub 1/ resulting from deexcitation through the first excited state of Si/sup 28/ at 1.78 Mev. They were detected by a 5-in.-diam by 6-in.-long NaI(Tl) crystal. A Pb collimator was used to improve the resolution of the detector. The results indicated that both gamma /sub O/ and gamma /sub 1/ display the giant resonance behavior; the gamma /sub O/ carve reached a peak value of approximately -8 mu barns/sr at E/sub p/ = 8.75 Mev, while the gamma /sub 1/ peak was approximately -14 mu barns/sr at E/sub p/ = 10 Mev. Both curves displayed the fine structure previously reported by Gove et al. A detailed balance calculation was made, using the gamma /sub O/ data. A comparison with the measurements of Johansson on the total yield of protons from the Si/sup 28/( gamma ,p)Al reaction …

Two groups of plutonium bars, one group containing 165 ppm iron and the other 678 ppm iron were end-quenched from the beta, gamma, delta, delta-prime, and epsilon phases. In general, cooling rate was found to have three striking effects on microstructure. The alpha grain size was found to decrease with increasing cooling rate during cooling from all phases. Upon cooling high-iron plutonium from the epsilon phase, the size of the Pu--Pu6/sub 6/Fe eutectic network decreased with increasing cooling rate. Cooling high-iron plutonium from temperatures between 413 and 460 deg C produced a wide variety of Pu --Pu/sub 6/ Fe configurations in the microstructure. Finally, the size of an unidentified spheroidal inclusion, soluble in the delta and higher temperature phases, decreased as cooling rate increased across the delta to gamma transformation. These effects of cooling rate can be used to indicate the cooling rate or thermal history that a particular plutonium specimen has encountered. A linear relationship between the alpha grain size and the Pu--Pu/sub 6/Fe eutectic network size was observed. The network size was roughly two times larger than the alpha grain size. Hardness traverses on each of the bars indlcated no apparent effect of coollng rate during quenchlng on …

The effect of temperature on the unnotched and notched Charpy impact properties of plutonium was studied in the alpha, beta, gamma, and delta phases encompassing a temperature range of -43 to 330 deg C. Impact energies for unnotched specimens generally increased with increasing test temperature in the alpha and beta phases. Brittle failures were obtained in these phases. The specimen tested in the gamma phase did not fracture but bcnt in ofi U-shape and pulled through the anvil. lmpact energies for the Charpy V-notched specimens were much lower than for the unnotched spcc(mens.dt corresponding temperatures. Brittle failures were obtained in the alpha and beta phases; some ductility was evidenced in the gamma phase while the specimen tested in the delta phase did not fracture but bent in a U-shape. It was concluded that the beta phase is quite sensitive to both strain rate and notch effects. Fracture appearance in the alpha and beta phase is discussed from the standpoint of grain boundary effects and microcracking. (auth)

ABS>A review of laboratory diffusion studies on uranium and its compounds and alloys is presented. Included are results and analysis of studies on diffusion in single-phase and in multiphase U alloys, diffusion of gases in U, and diffusion in UO/sub 2/. (J.R.D.)

Tables are presented of experimental differential neutron cross sections for the elastic scattering of neutrons by nuclei in the energy range of 0 to 15 Mev. Nuclear reactions induced by neutrons are also included, particularly those that are significant for reactor-type calculations. The tables include nuclei from H to Pu. (D.L.C.)

A kinetic model of the primary loop of a multi-pass pressurized water reactor power plant is developed to evaluate, by analog computer techniques, the transient response characteristics under conditions of steam generator load and reactor control rod perturbations. Using the 2-pass 28 Mw(t) SM-2 reactor as a typical plant, transient behavior patterns are illustrated and examined for a variety of load inputs, variations in plant constants, and analog model simplifications. (auth)

A review of the nuclear and chemical features of uranium is presented. The problems of dissolution of a sample and counting techniques are discussed. A collection of radiochemical procedures for the element as found in the literature is included. (M.C.G.)

The results of experiments and planned work of the Department of Chemistry, Arkansas University, in nuclear chemistry and physics, theoretical physics, and organic isotope chemistry are discussed. The absolute activation cross sections for 14.8-Mev neutrons were determined for a large number of isotopes, and a new isotope was found in the Fe/sup 54/(n,t) reaction. The (n,2p) reaction was studied in detail. A number of (n,He/sup 3/) and (n,t) reactions were studied. A literature survey (up to 1958) was made for cross sections of neutron-induced reactions around 14 Mev. The (n,p) reaction survey was continued up to date. The literature data have a large spread with factors of 2 to 10. Equations were derived from the (n,p) data giving the cross section as a function of atomic number and mass. The yields for U/sup 238/ 14-Mev fission were measured at mass numbers were studied. The theoretical aspects of molecular excitation resulting from beta decay of a constituent atom are being studied. Calculations were made on the wave functions of the ground state of the helium atom. The acid-catalyzed rearrangements of ketones were studied with both labeled and unlabeled compounds. No cyclic ketones were found to rearrange. The mechanism of the oxygen …

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Organic reactor technology is critically evaluated and areas of research and development work now lacking or inadequate for the successful development of this reactor concept are indicated. The development programs for present organic and heavy water moderated concepts appear generally adequate to reach specific goals. However, the narrow scope of the organic reactor program should be broadened to assure coverage of areas where the application of novel principles might result in marked economic benefits. Further work, principally of a basic nature, is recommended in the fields of chemistry, processing, management, and thermodynamic properties of coolants, in fuel development, and in concept evaluation. (N.W.R.)

THESE TWO VOLUMES CONSTITUTE A RECORD OF THE TECHNICAL, ADMINISTRATIVE , AND POLICY-MAKING ACTIVITIES OF THE LOS ALAMOS PROJECT (PROJECT Y) FROM ITS INCEPTION UNDER THE MANHATTAN DISTRICT THROUGH THE DEVELOPMENT OF THE ATOMIC BOMB (VOL. I), AND DURING THE PERIOD FOLLOWING THE END OF WORLD WAR II UNTIL THE MANHATTAN DISTRICT RELINQUISHED CONTROL TO THE ATOMIC ENERGY COMMISSION AS OF JANUARY 1947 (VOL. II). ALTHOUGH SEC URITY REGULATIONS HAVE REQUIRED SOME DELETIONS IN THE ORIGINAL TEXT OF THE TWO VOLUMES, EVERY EFFORT HAS BEEN MADE TO RETAIN THE ORIGINAL LANGUGAGE AND EXPERSSIONS OF THE AUTHORS.

Results are discussed for investigations of: elastic scattering of bound nuclei; center-of-mass energy in Overhauser's self-consistent field with giant density fluctuations; the distorted-wave theory of direct nuclear reactions; an excitation method for an optical maser; energy spectra for BETA decay of He/sup 6/; electron shake-off following He/sup 6/ decay; neutrons from He/sup 3/ bombardment of Be/sup 9/, Ci/sup 1//sup 3/, and Li/sup 7/; total neutron cross section of Pb/sup 2//sup 0//sup 8/; neutron total cross sections for selenium isotopes at 4 to 50 kev; statistical parameters of nuclei from kev neutron total and capture cross sections; high-resolution total neutron cross sections of Am/ sup 2//sup 4//sup 1/ and Np/sup 2//sup 3//sup 7/; Breit-Wigner resonances; neutron radiative capture at 200 to 6000 ev; gamma spectra from 30-kev neutron capture; gamma - gamma angular correlations in Xe/sup 1//sup 3//sup 2/; Coulomb excitation of levels in Se/sup 7//sup 7/; Mossbauer method of HFS splitting of Au/ sup 1//sup 9//sup 7/ alloys wlth iron, cobalt, and nickel; magnetic ordering in rare-earth intermetallic compounds; frequency calibrations of prism spectrometers and spectral slit-width measurements; vapor-phase infrared absorption spectra of HfF/sub 4/, TiF/sub 4/, and ZrF/sub 4/; polarized deuteron sources; pulse characteristics of fast phototubes; properties of …

Isothermal reaction curves and T-T-T curves showing the effect of different variables on the beta-alpha transformations in plutonium are presented. Impurity content, stresses, beta heat-treating time and temperature, hydrostatic pressing, specimen size, and thermal cycling influenced the kinetics of the beta- alpha transformation. Decreasing the impurlty content increased the rate of transformation. High tensile stress retarded the beta-alpha transformation. Increasing the beta heat-treating time and temperature markedly decreased the rate of transformation. Hydrostatic pressing at 90,000 psi accelerated the beta- alpha transformation under pressure but decreased any subsequent beta-alpha transformations by as much as two orders of magnitude. Specimen size had no effect on the start of the transformation but increasing the specimen size from 0.010 to 0.37 inch decreased the rate of completion of transformation several orders of magnitude. Thermal cycling less than 15 cycles did not affect the rate of transformation. The density of high purity plutonium during hydrostatic pressing at l80 deg C and cooling under pressure increased from 19.60 to 19.65 g/ cm/sup 3/to 19.70 to 19.75 g/cm/sup 3/. This increase was shown to be attributed to decreasing the volume of microcracks rather than transformation of any metastable beta phase. A T-T-T curve of the alpha-beta …

A bibliography of 240 references is presented on the extrusion of U, U alloys, and U compacts. The references were taken from Nuclear Science Abstracts and cover the period Jan. 1951 tc June 1961. (D.L.C.)

Concern for the protection of water-sensitive components by storage in pressurized containers prompted this study of leakage from pressurized containers. Work carried out to determine leakage rates, which will ensure a positive pressure within the container for a specified storage period, is summarized. These analyses considered molecular flow and two cases of viscous flow through physical gaps or holes in the container. (auth)

Progress in radiobiology and caneer research is reported. Topics covered include: comparison of the effects of isologous, homologous, and heterologous hematopoietic tissues on post-irradiation survival; survival of transfused blood in rats; erythropoietic response to erythropoietin; inhibition of erythropoiesis by estrogens; tryptophan metabolism; effect of daily exposure to l5-r gamma radiation on susceptibility of mice to experinrental infection; restorailon of serum bactericidal activity and prevention of its loss in x- irradiated mice; immunohistochemical study of Ehrlich ascites tumor; comparison of effects of I/sup 131/-induced hypothyroidism and L-triiodothyronine on irradiated hair roots in mice; modification of radiation responses of tissue by colchicine; production and use of I/sup 131/; localization of ocl evaluation of brain scanning system; thick target yield and excitation function for the reaction Rh/sup 103/(p,n)Pb/sup 103/; incorporation of C/sup 14/ and tritium precursors into brain; net synthesis of RNA with a microleial enzyme requiring DNA and four ribonueleoside triphosphates; snythesis of (P/sup 37/) uridine 5'- phosphate; and of 17- alpha -hydroxyprogesterone-4-C/sup 14/-l7 alpha -caproate by homogenates of rat liver and human placenta. (M.C.G.)

The technique of radiation characterization is reviewed, with particular emphasis on new methods and their practi-cal aspects. Each type of detector is discussed in terms of its principle of operation and its applicability to various problems in counting and spectrometry. Auxiliary electronic instrumentation and the function of each instrument are described in general terms. Other topics discussed include low-level counting, absolute counting, and the mounting of radioactive sources. (137 references.) (C.H.)