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Chain Reaction of Pure Fissionable Materials in Solution

Description: 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.
Date: January 1, 1943
Creator: Christy, Robert F., 1916-2012 & Wheeler, John Archibald, 1911-2008
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effective Temperature of Neutrons in a Lattice

Description: The average energies of neutrons emitted from a graphite column at 22 degrees C were compared by measurement of the cross section of boron for neutrons which are stopped by cadmium. At a distance from the neutron source great enough to insure that the neutrons were in thermal equilibrium the average energies of the emerging neutrons were found to be proportional to the temperature within the limits of the experimental error. A measurement made with boron absorbers which had been thus standardiz… more
Date: February 10, 1943
Creator: Woods, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Radioactivity of the Cooling Water

Description: 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.
Date: March 1, 1943
Creator: Wigner, Eugene Paul, 1902-1995.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Effect of Fast Fission on k

Description: The importance of fast neutron fission (i.e., fission caused by neutrons before being slowed down) was recognized by Szilard, and calculations similar to the present one have already been carried out by him, Feld, Ashkin, Wheeler, Wigner and others. The purpose of the present paper is to give a general formula for the contribution of fast fission to the multiplication constant, which will include all the cases already considered and will be applicable to more complicated geometries than those c… more
Date: May 4, 1943
Creator: Castle, H.; Ibser, H.; Sacher, G. & Weinberg, Alvin Martin, 1915-2006
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Contamination of Cooling Water by a P-9 Plant

Description: 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.
Date: June 1, 1943
Creator: Friedman, Francis L. (Francis Lee), 1918-
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Resonance Absorption Spectrum of Uranium

Description: A model for the capture spectrum of uranium is introduced in which levels occur at 7, 30, 30+D, 30+2D, ..., ev. Gamma ray and neutron widths are derived from the experimental data for values of D between 10 and 25 ev. The constants of the 7 volt level prove to be independent of D. Extrapolation, using the one level formula, gives a capture cross section at (1/40) ev of 4.9 x 10(24) cm2; this number is, however, quite sensitive to the value taken for the resonance activation. Both neutron and ga… more
Date: November 24, 1943
Creator: Dancoff, Sidney M., 1913-1951
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Eta Temperature Effect

Description: The temperature coefficient of eta has been measured with the thermal column of the Argonne pile using uranium foils of different isotopic ratios. The temperature change was effected by filtering neutrons through silver. The measured fractional change per degree centigrade is [formula].
Date: February 25, 1944
Creator: Bragdon, E. W.; Hughes, D. & Marshall, John
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Pile Safety Circuit

Description: The present report is concerned with the electronic relay which, upon the reaching of a pre-determined value of ionization current in the associated chamber, actuates the safety rod release mechanism. The are here proposed two independent suggestions: (1) An improved trip circuit of such sensitivity and stability as to allow it to be actuated by a signal directly from the chamber without the necessity of interposing intermediate amplifier stages. The value of chamber current at which tripping … more
Date: April 14, 1944
Creator: Nierman, Leonard G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Resonance Absorption in Lumps and Mixtures

Description: The resonance absorption of a lump is described in terms of three components. Calculations of resonance absorption are carried out using the model for the resonance spectrum of uranium recently derived; calculations are also made with variations of this model which involve local fluctuations in level strengths. For metal and oxide lumps the agreement with observation is satisfactory. For dilute mixtures, whose resonance activation was measured by Mitchell, computed values fall 20% to 30% above … more
Date: April 17, 1944
Creator: Dancoff, Sidney M., 1913-1951 & Gingburg, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Determination on Neutron Density With Bismuth Foils : Final Report - Problem Assignment 131 - X21P

Description: It is usual to determine the density of neutrons by using foils of metals which become radioactive as a result of bombardment in the region under investigation. From the rate of disintegration of the newly formed radioactive element the number of neutrons absorbed can be calculated. By use of the capture cross section of the element of which the foil is composed the density of the neutrons can then be computed. By counting the alpha particles from a bismuth foil of known weight after exposure t… more
Date: May 30, 1944
Creator: Curtiss, Leon Francis, 1895-
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Resonance Absorption of Uranium in Mixtures

Description: A good determination of the resonance absorption of uranium when admixed with various substances is necessary so that calculations can be made on the efficiency of homogeneous piles. The original experiments along these lines were undertaken by Creutz, Jupnik, and Snyder (C-116) and consisted of experiments on the resonance capture in pure U, UO2, U3O8, and one experiment on capture in a mixture of U3O8 and graphite. These experiments were done at the cyclotron in Princeton and consisted of det… more
Date: March 31, 1944
Creator: Mitchell, Allan C. G. (Allan Charles Gray), 1902-; Brown, Leon J.; Pruett, John R. & Nering, Evar D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Metallurgical Laboratory, Nuclear Physics Division, Report for the Month Ending May 25, 1944

Description: Technical report with short reports from the (1) Experimental Nuclear Physics Group; (2) Theoretical Physics Group ; (3) Lattice Design Group; (4) Pile Design Group; (5) Exponential Experimental Group; (6) Radiation Group; and (7) Shielding Group.
Date: June 14, 1944
Creator: Fermi, Enrico, 1901-1954
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experiments on the Evaporation of Boron in Vacuo : Progress Report No. 1 on a Phase of Problem No. 132 - ML - 56-3; File Serial 13

Description: It was desired to determine a method of evaporating boron to form a rather pure uniform tenacious coat of specified thickness. These coats are needed as monitoring films for neutron intensities, particularly in steel ionization cylinders. The most satisfactory method of evaporating boron employed a graphite filament. A mixture of amorphous boron and Carbenoid A was painted onto the filament which was then heated by electrical resistance method to 2300 degree C at which temperature the boron eva… more
Date: March 31, 1944
Creator: Friel, D. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Representation of Slowing Down Functions in Water by Synthetic Kernels

Description: 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.
Date: June 1, 1944
Creator: Cahn, Albert, Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Effect of the Maxwell Distribution of Velocities on the Neutron Density and Diffusion Length in a Metal Sphere

Description: The change in the simple [formula] distribution of neutrons in a spherical lump of uranium caused by the distribution in velocities of thermal neutrons is calculated. If the calculated curve is fitted as well as possible by a simple [formula] curve, it is shown that the value of [formula] obtained in this way is a function of [formula], the radius of the sphere. For small radii the [formula] obtained in this manner will be as much as 25% greater than the [formula] corresponding to average veloc… more
Date: June 27, 1944
Creator: Plass, Gilbert N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sealing of Holes in Aluminum Sheet by Oxidation

Description: Aluminum oxide occupies a larger volume than the aluminum it contains would fill as metal, consequently, the assumption has been made that holes in metallic aluminum would close by a sufficient amount of oxidation. Therefore, we were asked to investigate the rate of plug formation under conditions to be expected in the pile. For the latter we were requested to approach the pile conditions as nearly as we could by employing the Chicago cyclotron. It seems to us that the problem divides itself in… more
Date: July 15, 1944
Creator: Anderson, S. & Goldowski, N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Distribution of Thermal Neutrons in a Slug with Thick End Caps

Description: The distribution of thermal neutrons in a W slug having a one centimeter aluminum end cap has been calculated on the basis of simple diffusion theory. It is found that the average neutron density, and therefore the power output, at the end of the slug is about 34% higher than the density far from the end cap. This result agrees well with the recent Argonne pile experiments (CP-1729).
Date: August 3, 1944
Creator: Wilkins, J. Ernest, Jr., 1923-2011
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Interaction of Be with Fission Neutrons

Description: To determine whether or not the (n,2n) reaction in Be would produce a net increase in fission neutrons in a power plant, the distribution of In resonance neutrons slowed down from fission energies in a graphite block was measured with and without a 2" of Be in front of a U3O8 slab undergoing fission. The thermal neutrons producing the fissions were obtained by slowing down neutrons from a cyclotron source. The observed distribution without Be was well represented by a Gaussian source range 36 c… more
Date: April 29, 1942
Creator: Borst, L.; Allison, S. K.; Wheeler, John Archibald, 1911-2008 & Weinberg, Alvin Martin, 1915-2006
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Poisoning and Production in a Power Plant

Description: The yield of 49, the efficiency of production of 49, and poisoning in a power plant are discussed. Only the crudest of estimates of the poisoning are possible: these indicated that production will probably not be hampered by poisoning. In this case the yield of 49 could be as high as 3 kg/ton but only about 2 kg/ton is compatible with a fairly high efficiency. In the case that production is stopped by poisoning, smaller yields, proportional to the tolerable loss in k, are obtained. In this case… more
Date: December 15, 1942
Creator: Ashkin, J.; Christy, Robert F., 1916-2012 & Feld, Bernard T. (Bernard Taub), 1919-1993
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Low-Density UO2 Pile

Description: The multiplication factor and minimum pile size for a multiplying pile using UO2 powder of density 1 have been computed. It appears that a k of 1.0177 is possible for a volume ration of V/V001=3.33.
Date: February 24, 1943
Creator: Ibser, H. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Temperature Coefficient of the Reproduction Factor for Different Lattice Arrangements

Description: The temperature coefficient is calculated for various lattice arrangements, taking into account the variation of [formula], suggested by Fermi. Four contributions are included: leakage, levelling of the dip in thermal neutron density in the lump, resonance absorption, and hardening of the neutrons as they penetrate a metal lump. The departure of neutron temperature from lattice temperature decreases the total coefficient. Values are given for 3 typical piles; in general, the larger the uranium … more
Date: February 10, 1943
Creator: Morrison, P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of Temperature on the Resonance Absorption of Neutrons by Uranium

Description: The resonance absorption of uranium for neutrons has been investigated between 20 degree C and 1000 degree C. Experiments were caried out on both UO2, density 4.63, and metal. The resonance activity was measured with respect to that of an iodine monitor at several different temperatures and the ratio of activity at temperature T to that at 20 degree C was determined. The increase in activity is 0.9 per cent per 100 degree C for the oxide and 1.1 percent per 100 degree C for the metal. The perio… more
Date: April 22, 1943
Creator: Mitchell, Allan C. G. (Allan Charles Gray), 1902-; Slotin, Louis; Marshall, John; Nedzel, V. A.; Brown, L. J. & Pruett, John R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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On the Multiplication Constant of Homogeneous Mixtures of U with Various Moderators

Description: The following represents a summary of calculations on the multiplication constant of homogeneous mixtures of uranium and different moderators. These calculations were made possible by Fermi's determination of the age of neutrons and by the extrapolation to higher scattering cross-sections of the resonance absorption of uranium as measured by C. Creutz. According to Fermi, the former quantity is 120 sq. cm. The latter is given in the two attached graphs. The first (Fig.1) of these goes as high a… more
Date: May 16, 1943
Creator: Wigner, Eugene Paul, 1902-1995 & Stephenson, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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