Recent measurements on the long counter efficiency in which comparisons were made with the (n, p) scattering cross section, additional variations in efficiency were found which varied slowly with neutron energy but were still correlated with the total neutron cross section of carbon. Because of these variations in efficiency there are errors in the fission cross sections reported in LA-1714. Corrections to these data have been given here.

Abstract: "Measurements have been made of the cross sections for the reactions Id-6(n, dn)He-4 and Li-7(n, tn)He-4 over an incident neutron energy range of 5 - 14 MeV. The energy and angular distributions of all reaction products were determined."

Preface: This report contains data and information on the resurvey effort and the effect of residual contamination as a result of nuclear weapons development programs conducted in this area.

It has been found relatively easy to form uranium in the gamma phase temperature range by hot pressing, forging, or extrusion. The metal is quite plastic and flows readily to form a shape. Several temperatures from 800 degree C to 1000 degree C were investigated. No forming difficulties were experienced with the metal at the several temperatures concerned. The major difficulty in gamma phase hot pressing or extruding was associated with the tools. Metals or ceramics were not successful as tools for one or more reasons concerned with: lack of hot strength, reactions with the uranium, failure in thermal shock, and tendency to spall. Graphite was found to be the best material available, but it is not entirely satisfactory because of low strength. Uranium formed in the gamma phase possesses some refinement of grain structure as compared with as-cast metal; however, the grain size is quite large. No physical properties of the gamma phase formed metal were determined.

Abstract: "A theoretical and experimental investigation is made of the diffraction pattern produced by a slit, whose aperture varies uniformly from a constant value A to zero. The results of this investigation are applied to a proposed high speed camera. It is shown that diffraction effects are very serious and cannot be neglected. It seems, unless the suggested design of this high speed camera is changed, the camera will be of little use for accurate measurements, and photographs will show too much blue to give details."

This technical report summarizes the apparent hematological changes in 10 individuals, exposed to total-body gamma radiation in near tolerance amounts, over a period of four and one-half years. Two control groups, in addition to the exposed group, were used for comparative purposes. Control group I received essentially no gamma or beta radiations. Control group II received exposures at least a factor of 10 below those of the exposed group. The average total leukocyte count, absolute neutrophil value, and absolute lymphocyte value, were determined for each individual and for all groups. Analysis of data indicates a significant depression of the absolute lymphocyte value of the exposed group as compared with those of the control groups.

A technique for the fusion welding of uranium has been under development and several methods of fusion welding have been investigated. The inert gas, shield arc method has proven to be the most satisfactory of the processes thus far examined. Uranium properly weld by this method was free from porosity, cracks, and oxide inclusions. Certain precautions and some special techniques were required to make good welds.

Most books on the subject of gas discharges describe the multiple banded structure which appears in the flow between two electrodes. This structure is actually due to the difficulty in getting electrons out of the cathode to support the discharge. These electrons are obtained by having a large enough potential drop near the cathode so that the positive ions may strike it hard enough to product secondary electrons. If one substitutes a hot cathode to produce a copious quantity of electrons, the banded structure will be radially changed. Hence the banding is not a pure property of the discharge, but is a complication brought on by the presence of electrodes.

The proposed Los Alamos Omega West Reactor is designed to be a research tool delivering a maximum neutron flux of approximately 5 x 10/sup 13/ n/sec/cm/ sup 2/ at its maximum operation power level of 5 megawatts. Solid fuel elements of the type developed for the Materials Testing Reactor will be utilized. Cooling will be accomplished with circulating demineralized water and evaporative coolers. Experimental facilities will include numerous horizontal ports, two of which will incorporate built-in rotary beam shutters, and a thermal column. If all the radioactive material contained in the fuel elements during normal reactor operation were to become spread through the residential area of Los Alamos, persons in some parts of the city would be exposed to greater than lethal doses. It does not appear that known mechanisms could operate to produce this situation. Because of geographical relationships and low ground-water flow velocities, there seems to be no likelihood of water supply contamination in the event of a reactor disaster. Care has been taken in the reactor design to insure against sudden draining of the main reactor tank containing the fuel assembly, as such a sudden loss in cooling might lead to damage of the fuel elements. Conservative …

A method is presented for determining heat transfer rates and thermal stresses from the gamma-ray energy absorption of nuclear reactor shells for plane, cylindrical, and spherical geometries. Criteria for minimizing thermal stresses are developed, along with the corresponding external cooling rates necessary to minimize the thermal stress. Design charts are presented for rapid determination of approximate thermal stresses and heat transfer rates, along with a numerical example illustrating the use of the charts..

Purpose: "The purpose of this investigation was to determine whether or not the machinability of extruded beryllium rod could be improved by appropriate heat treatment. It was thought that this could be accomplished in the extruded Be rod by recrystallization without further growth of these grains. This should impart a certain degree of ductility to the metal. The investigations was divided into two parts: Part I - Heat Treatment of Beryllium Rod; Part II - Machinability of Beryllium Rod."

This paper is issued in two volumes: LA-1664 and LA-1665. In LA-1664, the fundamental properties of a shock in free air are described, including the reasons for failure of similarity scaling. The results of an analytic solution for strong shocks are presented, which permit a determination of the energy in a shock wave from its rate of growth without recourse to similarity assumptions; from it the scaling laws for both homogeneous and inhomogeneous atmospheres are explicitly shown. The total energy is evaluated in a machine calculation for the blast wave and from this evaluation, the free air wave form for all hydrodynamic variables is presented. The general nature of the laws governing thermal radiation from atomic bombs is deduced, a new figure of merit for thermal radiation is suggested to replace the concepts of “thermal energy” and “critical calories,” which are considered ambiguous. Partition of energy is considered negligible in most cases of interest; the waste heat concept is reconsidered and the failures of scaling to TNT are regarded primarily as a failure of the ideal gas law. LA-1665 is concerned with preparation of height of burst curves. In the reflection process over ideal surfaces, the usual subdivision into regions …

This paper is issued in two volumes: LA-1664 and LA-1665. In LA-1664, the fundamental properties of a shock in free air are described, including the reasons for failure of similarity scaling. The results of an analytic solution for strong shocks are presented, which permit a determination of the energy in a shock wave from its rate of growth without recourse to similarity assumptions; from it the scaling laws for both homogeneous and inhomogeneous atmospheres are explicitly shown. The total energy is evaluated in a machine calculation for the blast wave and from this evaluation, the free air wave form for all hydrodynamic variables is presented. The general nature of the laws governing thermal radiation from atomic bombs is deduced, a new figure of merit for thermal radiation is suggested to replace the concepts of “thermal energy” and “critical calories,” which are considered ambiguous. Partition of energy is considered negligible in most cases of interest; the waste heat concept is reconsidered and the failures of scaling to TNT are regarded primarily as a failure of the ideal gas law. LA-1665 is concerned with preparation of height of burst curves. In the reflection process over ideal surfaces, the usual subdivision into regions …

A high-vacuum casting furnace with an internal diameter of 15 inches has been designed, fabricated, and installed at LASL. The furnace was designed to accommodate casting crucibles up to 7 inches OD; however with a larger diameter heating element, casting crucibles up to 9 inches could be accommodated. This report describes the basic features of the furnace and presents engineering drawings of both the furnace and the furnace box.

A criticality equation is derived assuming slowing-down only by hydrogen. The use of criticality experiments as a basis for calculation is described. Approximate methods are given for handling inharmonicities and multi-region reactors. Some criticality data on solutions of U03 dissolved in H3PO4 are listed in Appendix 1, and the Goertzel-Selengut equations are derived in Appendix II.

Uranium has been successfully impact extruded into typical cylindrical shapes of conventional design. Extrusion was carried out in the "gamma" region by heating cast uranium slugs to a temperature of approximately 1050 degrees C. Protection against oxidation was afforded by surrounding the slugs during heating with an inert atmosphere of argon gas. Impact extruded shapes possessed physical properties which are better than the properties of as-cast metal. Also, extruded shapes show a uniform internal structure with flow lines characteristic of commercial impact extruded pieces formed from other metals. Impact extrusion, as a fabricating processes for uranium, maybe applied successfully to produce complicated shapes or forms not practical by casting or where savings in metal and machining time is desired. The process would not appear to be commercial unless a large quantity of pieces was required.

A batch-type incinerator has been built which will dry and burn 12 liters of wet, packed rags or the equivalent in other organic matter in 8 hours. The material is ignited and burned in a stream of oxygen. Tars in the off-gas are trapped in a water bubble, residual contaminated particles are caught by a CWS filter, and acid vapors are reacted in a caustic scrubber. The unit was designed to processes plutonium residues; however, other radioactive materials could be handled by the use of appropriate shield and manipulators.

The transmissions of neutrons through spherical shells of normal uranium, oralloy, and Pu239 are reported. One group of measurements was made using a pure fission neutron source produced by thermal neutrons. The other group of measurements was made using monoenergetic neutrons. From both groups of measurements, the inelastic scattering cross sections have been determined according to methods developed in Los Alamos Scientific Laboratory Report LA-1429 (Jaunary 1955).

With the assumption of infinite conductivity a simple model may be constructed for the dynamic construction of a current carrying plasma, i.e., the pinch effect. The magneto-hydrodynamic equations of this model are discussed and solved. It is also shown that the infinite conductivity model can be derived from a picture of particles orbiting without collisions in the fields set up by their motions.

Four uranium alloys containing nominally 0.5, 1.0, 1.5, and 2.0 w/o molybdenum were investigated with respect to their response to hardening by heat treatment. The several alloys were heated at elevated temperatures to secure solid solution, then quenched and reheated at lower temperatures to obtain hardening. The procedure followed the well known industrial practice of solution treatment and precipitation hardening. The results showed that all the alloys could be hardened by a suitable heat treatment. No specific temperatures are recommended; however, within the limits of the investigations, a solution treatment at 850 degree C followed by a water quench and reheat at 450 degree C gave a considerable increase in hardness. The time at temperature to secure maximum hardness would need to be determined as a function of mass and section shape. It is presumed that other mechanical properties of the alloys would be influence by heat treatment in a similar manner corresponding tot he effect upon hardness.

Abstract: "Static measurements have been made of the currents produced by Co-60 gamma irradiation of solid dielectric RG 8/U cable. Sensitivity curves are presented as a function of the magnitude and polarity of the collection voltage to 90 volts. It is shown that the current is due to a polarity- and voltage-sensitive ionization component and to a polarity- and voltage-insensitive component attributed to the Compton process. The total cable sensitivity at -90 volts, with saturation not achieved, was (11 +/- 1) x 10-(-12) coulomb per roentgen-meter of cable, or 0.08 percent of what one would expect from ionization in an air dielectric cable of this volume."

Exponential rise times, T, of neutron flux in an Oy-Tu assembly have been measured for a set of points essentially equally spaced reactivity-wise in the interval between delayed and prompt critical corresponding to [infinity] > T > 5 seconds. The relationship between positive period and reactivity thus obtained is used to decide (preferentially) between two currently used but divergent collections of delayed neutron data, specifically with respect to the relative abundances of delayed neutrons in the different decay periods. Results of other reactivity measurements supplementing the positive period data are also given.

Plutonium metal can be injected into cold metal molds to form castings with thin walls. The operation is performed in a vacuum chamber, using an inert gas as the injecting medium. Sound pieces free of gas cavities can be made using either pure or delta-stabilized plutonium. This report describes the equipment and techniques used to cast a typical thin section piece in the form of a 6 in. diameter, 45' cone.

The stability of a pinched plasma equilibrium with a longitudinal magnetic field superimposed on the characteristic azimuthal magnetic field of the pinch current is studied theoretically. The linearized solutions are developed as helical perturbations of the plasma surface, and the behavior of these is given for the different cases of uniform longitudinal, longitudinal field zero inside the plasma, and for helices of the same and opposite sense to the helix which describes the total magnetic field. Very approximately, the conclusions are: that the longitudinal field has the effect of stabilizing short-wave perturbations, but that some long-wave perturbations remain unstable no matter how large the externally imposed longitudinal magnetic field.