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Leakage Neutron Spectrum of U²³³ Critical Assembly

Description: Abstract: "The leakage neutron spectrum of a U²³³ spherical critical assembly (Jezebel) has been measured using nuclear emulsions as radiator and detector. The spectrum obtained is compared with similar measurements on the U-235 and Pu-239 analogues of Jezebel U²³³; it is found to agree closely with that of the Pu-239 assembly and to be harder than that of the U-235 assembly. All three spectra are compared with theoretical spectra obtained from a numerical approximation to the neutron transport equation."
Date: September 1962
Creator: Bobisud, Larry E.
Partner: UNT Libraries Government Documents Department

6.70 EV Resonance in U²³⁸

Description: "Using the Brookhaven fast chopper, transmission curves were obtained for the 6.70 +/- .06 ev resonance in U238 using four different thicknesses of natural uranium metal." The measurements for the transmission curves are summarized in the table provided.
Date: November 9, 1953
Creator: Levin, Jules S.
Partner: UNT Libraries Government Documents Department

The U²²⁷ Collateral Series

Description: The following report describes data from the continuation of investigations which led to the observation and characterization of five artificial radioactive chains collateral to the natural radioactive families that has lead to the partial identification of one additional chain, collateral to the actinium family.
Date: February 21, 1951
Creator: Meinke, W. Wayne; Ghiorso, Albert & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Estimates of Minimum Critical Volumes

Description: Introduction: "A study has been made of the available high assay criticality data for materials of 93.4% and 95.3% U-235, 1, 2, 3 and minimum critical volumes have been estimated for several conditions."
Date: 1952
Creator: Rohr, R. C. & Henry, Hugh F.
Partner: UNT Libraries Government Documents Department

An Influence Function for the Beta Activity of Uranium(235) Fission Products

Description: Abstract: "Computations have been made of the total beta activity of the fission products arising from the slow neutron fission of U-235. A curve is given exhibiting the activity the activity per unit fission, for time intervals after fission ranging from 0.01 second to 10 years. This influence function is compared with some published experimental data and with the statistical curve of Way and Wigner. A curve facilitates estimation of the activity in the particular case where the fission rate has been constant throughout a known time interval. Finally, an influence function for the particular group of fission products consisting of complete and partial chains having volatile first members is given. This report is based on studies conducted for the Atomic Energy Commission under Contract AT-11-1-GEN-8."
Date: September 1, 1950
Creator: Thornton, J. Kendall & Houghton, William J.
Partner: UNT Libraries Government Documents Department

Critical Masses of Mildly Diluted U²³⁵ Systems Derived from Reactivity Contribution Data

Description: Abstract: "Radioactivity contribution data, obtained from U²³⁵ critical assemblies at Pajerito can be used to predict the effects of diluents on critical mass. The radioactivity contribution data versus radius for diluents in a given assembly may be expressed as a single functional relationship between integral absorption and transport cross sections of the diluents. Using this relation, there can be obtained a general expression for the dependence of critical mass upon volume fraction and the effective absorption and transport cross sections of the diluent."
Date: 1956
Creator: Engle, Leon B.
Partner: UNT Libraries Government Documents Department

A Determination of the U-235 Content in Highly Impoverished Material

Description: Introduction: "The product of a special run made in XAX was submitted to the Assay Department for a determination of the residual content of the 235 isotope. The charge material on this run was impoverished, with a ratio of approximately 1:2,000. The sample was submitted in the form of purified T3O8."
Date: 1946
Creator: Cameron, A. E. & Hibbs, Roger F.
Partner: UNT Libraries Government Documents Department

Variation of Critical Parameters Between U-235 Assays of 4.9 Percent and 93.5 Percent

Description: The following report uses empirical relations and the elementary diffusion theory transformation, the EDIT, to predict some of the minimum critical values of the various parameters of interest with reasonable accuracy. This document reports the minimal critical mass, volume, and cylinder diameter for uranium of 4.9% assay.
Date: October 23, 1953
Creator: Henry, Hugh F. & Newlon, C. E.
Partner: UNT Libraries Government Documents Department

U-235 Critical Mass Dependence on Moderation

Description: Introduction: "Based on experimental data and on conservative theoretical considerations, an estimate has been made of the relation of the mining U-235 critical mass to the hydrogen moderation for uranium material at the U-235 assays for which experimental information is available. These estimates have been used in indicating maximum safe amounts for conditions where definite moderation limitations can be established."
Date: September 22, 1952
Creator: Callihan, A. D.; Henry, Hugh F. & Macklin, R. L.
Partner: UNT Libraries Government Documents Department

Summary Report on Thorium Metal Quality for Production Reactor Use

Description: From abstract: "Background material leading to the development of the metal quality of reactor-grade thorium is given. The metal should be sound and of uniform hardness, free of internal cracks and inclusions, and corrosion resistant. It should contain only small amounts of natural uranium, thorium oxide, and elements that act as reactor poisons. Because of their effect upon metal quality, various methods for the production of thorium are discussed. Use of consumable electrode arc melting as the final step has contributed much to the production of thorium of excellent quality for reactor use."
Date: July 1958
Creator: Hayes, Edgar E.
Partner: UNT Libraries Government Documents Department

Observed Differences in the Arc Spectra of U²³⁵ and U²³⁸

Description: Abstract: "It has been found that the two principal uranium isotopes exhibit slightly different arc spectra. Certain U-235 lines have been found to be displaced from corresponding U-238 lines by about one reciprocal centimeter. The intensity ratio, IU235/IU238, has been shown to be a steadily increasing function of the U-235 concentration. These data indicate the possibility of developing a method for the determination of isotopic concentration by means of emission spectra."
Date: January 15, 1947
Creator: Long, D. R. & Smith, D. D.
Partner: UNT Libraries Government Documents Department

Analytical methods and results

Description: Report detailing the analytical methods and results of a study designed to measure the total alpha particle activity of samples. The method being used was previously in use at Columbia University. The report recognizes potential for grave errors, but makes no effort to minimize the effect of the roughness of the sample.
Date: 1945
Creator: Thomas, Henry C. & Bither, Tom Allen
Partner: UNT Libraries Government Documents Department

The Production of U₂₃₄ by a Modified Calutron

Description: Abstract: Three and nine-tenths milligrams of U234 have been produced using a Calutron. A Beta-size Calutron was modified to produce complete resolution of the U234 beam from the U235 beam. With Beta charge the U234 current was 4 microamperes. The samples were collected upon flat pieces of graphite bent to fit the E curve.
Date: May 21, 1946
Creator: McKinney, C. R.
Partner: UNT Libraries Government Documents Department

Critical Mass Measurements on Graphite U²³⁵ Systems

Description: Abstract: "Measurements have been made on pseudo-cylindrical graphite-enriched uranium unreflected systems. These measurements include both critical mass determinations and time dependent measurements using a pulsed neutron source to drive the assemblies."
Date: April 11, 1957
Creator: Carothers, James Edward
Partner: UNT Libraries Government Documents Department

Expressions for Conversion Ratio in a Th-U²³⁵ Converter

Description: "This memo shall be an attempt to write down in a consistent manner some expressions for conversion ratio so that a comparison can be made with regard to a uniformly loaded core versus a flattered zone surrounded by an unloaded region. The discussion will be limited to the type of loading that is at present being considered for the reactor - a checkerboard array of MTR fuel elements and feed elements; the unloaded reactor will consist of fuel elements only."
Date: December 19, 1951
Creator: Cohen, E. Richard, 1922- & Benton, A.
Partner: UNT Libraries Government Documents Department

The Value of Nu for Fission of U²³³ by 14 Mev Neutrons as Derived from Charge Distribution Measurements

Description: Abstract: "The charge distribution for fragments from fission of U-235 induced by 14 Mev neutrons, as given by Ford, has been examined to obtain the average number of neutrons per fission. On the basis of some assumptions which seem reasonable a value NU-5.2 +/- 0.5 is obtained. Some evidence is also given which points toward the validity of the Glendenin hypothesis of charge distribution as opposed to that of Present."
Date: 1958
Creator: Wahl, John S.
Partner: UNT Libraries Government Documents Department