The critical mass of 94-239 and the corresponding critical dimensions of homogeneous mixtures of 94-239 with various moderating media been calculated as a function of the concentration of 94. A simple transformation makes the figures applicated to92-235. the results are in essential agreement with the preliminary estimated made independently by Oppenheimer and Serber. The problem of the stability of a chain reaction in solution and questions of protection are discussed.

The most important source of radioactivity at the exit manifold of the pile will be due to O19, formed by neutron absorption of O18. A recent measurement of Fermi and Weil permits to estimate that it will be safe to stay about 80 minutes daily close to the exit manifolds without any shield. Estimates are given for the radioactivities from other sources -- both in the neighborhood and farther away from the pile.

The following sources of contamination in cooling water of the P-9 plant are considered: (1) Fission recoils, (2) Corrosion of metal, (3) Recoil from aluminum, (4) Induced activity in the water. It is found that for a P-9 plant of 3.5 x 10(4) KW contamination of the river at "X" should not exceed the .1 r criterion unless coating failure occurs. Tables of the amount of coating failure permissible are given as a function of holdup time.

Introduction: Measurements of polonium content in solids are usually performed by dissolving the material and preparing a thin sample which can be measured with one of the available instruments. A measurement of the radiation emerging from the thick sample should be sufficient to evaluate the polonium content. For this reason a calculation has been performed and the results have been compared with those obtained by the thin sample method. Obviously this proposed method using thick samples would be faster.

Fermi, Anderson, and Nagle's experimental distribution of Indium resonance neutrons around a point source of fission neutrons in water has been fitted by analytic expressions which are source functions in the two-group, three-group, Fermi and Christy-Wheeler pile theory. The Christy-Wheeler function (exponential followed by a Gaussian) is the best fit; the two-group function (exponential) is slightly better than the Fermi Gaussian.

Various experimenters have shown (H.H. Gersman U.S. Patent 2,335,590, Nov. 30, 1943; Aluminum Co. of America, various technical papers; also CT-482) that when a billet is extruded by proper technique into a rod (or tube by a floating mandril) that flow of material is streamline and and the extruded article is essentially a space replica of the billet, with linearly distorted coordinates. Advantage is taken of this fact in the manufacture of alclad tubing in which a billet containing an inner core of one alloy with the outer part of another alloy cast around it is extruded together into an integral tube, e.g., to combine high corrosion resistance with high strength. The following experiments were carried out because of the desirability of obtaining a control rod which can be water cooled (or immersed in P9) and which contains boron. For some pile structures it may be desirable to have the major portion of the energy released by the neutron absorption of the control rod be spend in the rod itself by the nuclear reactions [formula] rather than in the surrounding media as is the case when absorption of neutrons is by cadmium according to the reaction [formula]. In the later …

Technical report describing development of the Clinton alpha amplifier. The circuit for the Clinton alpha amplifier which is used with an Offner scaler is shown attached to the report. It consists of a pre-amplifier mounted in a cylindrical alpha chamber, followed by a three state amplifier and a pulse height selector in a separate cabinet. Pulses are fed from the pulse height selector in the amplifier to the input tube of the Offner scaler. Through the third stage of the amplifier, this circuit is exactly the same as the California circuit now used by the chemical section for alpha counting. A type 961 Offner scaler was used for these tests. None of the latest Offner scalers type961A, were available to us when the tests were made. Method of testing is given, results are tabulated, computations are made, and eight graphs are given. it appears that the Clinton amplifiers used with a Offner scaler will give substantially the same performance as that given by the California circuit.

Prior to operating a chain reacting, graphite moderated, water cooled uranium pile at Hanford, the corrosive action of water on uranium was studied. It was necessary to enclose the uranium cylinders in Al jackets. Preliminary data were available which indicated Al jacket corrosion might be influenced by the water temperature. Therefore, in order to specify safe operating conditions, it was desirable to know the temperature at any position on the Al jacket of a slug in the tube. Because of the experimental difficulties encountered in the measurement of the correct surface temperature, the problem has been attacked primarily from a mathematical standpoint. Mathematical formulae have been developed for most of the proposed Hanford designs. The purpose of this report was to evaluate and summarize the theoretical and experimental information for calculation of Al jackets surface temperatures for the design now installed at Hanford. Also, the summarized results were to be put into a form suitable for use in routine calculations. As a result of this survey, the Al surface temperature for the Hanford tube and slug design may be calculated with 15 degrees C by employing routine methods and certain simple factors and equations contained in this report. The factors …

Abstract. thorium can be precipitated as a salt of p-dimethylaminoazophenylarsonic acid at a pH of about 1.5. the precipitate, collected on a sintered glass filter is washed with dilute ammonium hydroxide to dissolve the dye. the amount of thorium is determined by measuring the concentration of the dye spectrophotometrically at a wavelength of 450 millimicrons. Zirconium, which interferes, can be separated and determined using the same reagent in strong hydrochloric. the behavior of thorium metal upon treatment with various acids and upon fusion withKHSO4 is described. three satisfactory procedures are given for dissolving the metal with sulfuric acid, phosphoric acid, and by a potassium hydrogen sulfate fusion. The laboratory was presented with the problem of analyzing for a large number of elements in O2 metal. the results of a systematic study of methods for effecting solution of the metal are offered here since they may be of some interest and use to other laboratories. The four methods which effected complete solution of the metal are (1) Sulfuric acid method; (2) Fusion method; (3) Phosphoric acid method; and (4) Nitric acid-hydrofluoric acid method.

Report discussing the results of an investigation of a test for statistical consistency of counter-scaler units.

Technical report with short reports covering (1) Effect of radiation on water and aqueous systems; (2) Effect of neutrons on graphite; (3) Effect of radiation on solid compounds; and (4) Scattering, stopping-power, ion-pair production, etc.

Technical report with short reports from the (1) Physics Section I; (2) Physics Section II ; and (3) Physics Section III.

Abstract. Thorium peroxide was precipitated from thorium nitrate solutions containing varying amounts of sulfate ion and of hydrogen ion. The washed solids were analyzed both wet and dry. Analyses were made for thorium, peroxide oxygen, sulfate, nitrate, and water contents. X-ray powder photographs of the dried samples by W.H. Zachariasen showed the presence of only two phases. When precipitated from high sulfuric acid, the solid phase was isomorphous with Th(OO)SO4.3H20. More weakly acid solutions whose sulfate content was varied over wide limits [SO4--/Th(IV) (in solution before precipitation) = 0.005 to 67.0] yielded a solid, isomorphous with thorium peroxide nitrate and containing 3.0 to 3.8 peroxide oxygen atoms for each thorium atom. The sulfate content of this latter phase varied continuously between the limits SO4--/Th(IV) = 0.34 to 0.01 with nitrate ion present when the sulfate content was very low. This continuous variation in composition is in agreement with the previously proposed structure of this phase.

Abstract: "A polarographic method for the determination of tuballoy in thorium peroxide cakes in all sold medium was found to give satisfactory results. Fluorescent analyses on effluents containing thorium gave good results if the thorium content was kept below 1 mg/liter."

Abstract: "A phase diagram for the uranium-cobalt system has been constructed, based on thermal, microscopic, X-ray and chemical data. The results indicate the existence of three compounds and two eutectics, one of which shows a lowering of the melting point of uranium by approximately 400 C."

Abstract: "Tests have been developed for both the qualitative detection and quantitative determination of fluorine in chlorine. The qualitative test is made by passing the gas through manganous chloride. If the pink solid tubes brown there is greater than 0.5 percent of fluorine in the gas. The quantitative test is a modification of the Steiger and Marvin Test with oxidized titanium solution."

From abstract: "This paper discusses a method for the determination of uranium on platinum discs which does not involve direct weighing of the deposited film. A statistical analysis of the results obtained indicates that the procedure is more consistent than that based on a gravimetric method and offers a relatively quick and convenient means for obtaining uranium assay results where an accuracy of approximately 99% is desired."

Abstract: Equations are given to calculate at least approximately the heating in solid and hollow cylinders, slabs and spheres. Short and long cylinders are treated as well as short and long solenoids. The complicated mathematics used to derive the equations given will be omitted as they may be found in the original references. Heating with a spark gap converter is covered. Equations are given which together with some experimental data should enable the reader to predict the efficiency, heating, or temperature to be expected as the charge or coil is changed. Units and conversion factors are mentioned briefly.

Abstract: Exceedingly pure uranium tetrachloride was prepared for use in determining the physical constants of the compound. Measurements were obtained of the melting point and boiling point at pressures ranging from the triple point pressure to atmospheric pressure. Calculations were made of the vapor pressure equation for the liquid, the heat of evaporation, molar boiling point elevation, the vapor pressure equation for the solid, and the critical temperature.

"The effect of a single vacuum sublimation of contaminated uranium tetrachloride, with fractional condensation of the vapors, was investigated to determine whether a high degree of purity would result. It was found that this procedure was an excellent and simple method for obtaining exceedingly pure uranium tetrachloride."

Report discussing experiments to determine if the tri-ether (referred to in the report as dibutyl carbitol or carbitol) "was susceptible of a high degree of reactivity when used as an extraction agent for the removal of uranium from aqueous solutions."

Abstract: An analysis of the improved Model Number 350 Process Monitor was made so that it could be determined if this instrument would fulfill the need for gamma radiation detection instruments in the production buildings of Y-12. The results of these tests indicated the possibility of marked improvement in the monitor characteristics with minor redesigns. After these improvements have been made, this instrument will be a satisfactory monitor for this area.

The following documents were compiled into a quarterly report that was to be published in the Radiobiology Volume of the PPR. The following reports provide data from the Biology department of the University of Chicago between May and August of 1947.

The following document is a compilation of quarterly reports from August 1946 to November of 1947 from the Biology Division of the University of Chicago.