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The Admittance and Transfer Functions of Solid Core Electromagnets

Description: The admittance and transfer functions of large, solidcore electromagnets were determined. The effects of eddy currents and hysteresis were considered in deriving the functions. The study was concerned with the type of magnet employed in nuclear physics research which requires very precise regulation of the magnetic field. The study originated during the design of an analyzing magnet regulator for the ORNL 63-inch cyclotron. (W.D.M.)
Date: January 18, 1960
Creator: Ziegler, N. F.

A Study of Spectrophotometric Methods for the Determination of Osmium

Description: The development of rapid, selective, and sensitive methods for the determination of osmium in liquid samples is reported. The specific application of primary interest was the estimation of microgram or milligram quantities of osmium in homogeneous reactcr fuel solutions which contain uranyl sulfate as the major component and corrosion products of stainless steel as minor components. (W.L.H.)
Date: January 20, 1960
Creator: Goldstein, G.

Interactions of Antiprotons in Hydrogen, Beryllium, and Carbon

Description: To determine the nature of the interactions between antinucleons and nucleons, it has been necessary to do an experiment in which the elastic, inelastic, and charge-exchange interactions could be measured. Improvements in the 6-Bev Bevatron have permitted production of a considerably larger flux of antiprotons, than was available in earlier studies. With the use of strong-focusing magnetic quadrupoles, a crossed electric- and magnetic-field spectrometer, and time-of-flight scintillation counters it has been possible to detect approximately 30 antiprotons per minute. By means of a system of 4{pi} solid-angle scintillation counters, it has been possible to measure these cross sections, including the angular distribution of elastic scattering. These cross sections have been measured for antiprotons scattered from hydrogen, beryllium, and carbon in the energy range from 133 to 333 Mev. Ball and Chew have assumed that pion exchange is responsible for the nucleon-nucleon interaction, and have used field theory to calculate the antinucleon-nucleon interaction. They have assumed that the pionic charge of the antinucleon is opposite that of the nucleon; thus, the exchange of an odd number of pions should change the sign of the potential. Outside the hard core, the exchange is assumed to be due to two pions, and the sign of the potential is not reversed for either the nucleon or the antinucleon case.
Date: March 1, 1960
Creator: Cork, Bruce

Neutron Flux Distributions in Natural Uranium Tubes

Description: Measurements were made in the Process Revelopment Pile (PDP) of the distribution of the thermal neutron flux in ten different D/sub 2/O-moderated lattices of natural uranium tubes. Both single and double fuel tubes were used at lattice spacings of 7 and 14 inches. Special corrections were required for epithermal flux shielding by the manganese detector foils. After these corrections were applied, good agreement was obtained between the measured flux distributions and correspending distributions calculated by the P/sub 3/ approximation to transport theory. (auth)
Date: March 1, 1960
Creator: Ponder, T. B.

Antiproton-Proton Cross Sections at 1.0, 1.25, and 2.0 BeV

Description: The antiproton--proton interaction was studied at three energies, 2.0, 1.25, and 0.98 Bev. Antiprotons produced internally in the Revatron and channeled externally by a system of bending magnets and quadrupoles were selected from background particles by using a gas Cherenkov counter and scintillation counters. At the two lower energies, an electrostatic-magnetic velocity spectrometer was used to reject background particles. A liquidhydrogen target was completely surrounded by scintillation counters so that all charged secondaries from the antiproton--proion interactions could be detected. With the information obtained from these counters, the --p-bar--p total, elastic, inelastic, and charge-exchange cross sections and the angular distribution of the elastic scatterings were obtained at each energy. The total cross section was found to be 80, 89, and 100 mb at 2.0 1.25. and 0.98 Bev. respeclively. The inelastic cross section was about twothirds of ihe total cross section at each energy. It was found that each of the partial cross sections was dropping off slowly with energy. The results were fitted by an optic al-model c alculation. (auth)
Date: March 15, 1960
Creator: Coombes, C. A.

The Molecular and Viscous Effusion of Saturated Vapors

Description: An investigation of the effusive behavior of saturated vapors over a range of source pressures from 10/sup -6/ atm in the molecular flow region to 1 atm is reported. The purposes of the investigation were to clarify the situation regarding the upper pressure limit to effusive flow, to examine the transition of effusive flow from molecular to viscous behavior, and to clarify some limited aspects concerning the question of vapor saturation within an effusion cell. Mass flow rates of mercury vapor effusing through a thin-edged orifice or long channels into a vacuum from a region of nearly saturated vapor were obtained. (W.D.M.)
Date: April 1, 1960
Creator: Carlson, K. D.

Dissociation of Molecular Ions by Electric Fields [Part 2]

Description: The reactions pi /sup -/ + p yields p + p + n and pi /sup -/ + p yields p + d were investigated. The calculations are based on thirdorder perturbation theory with pseudoscalar coupling between nucleons and pions and with a phenomenological treatment of the nucleon-nucleon interaction in the final state. The final-state interactions of the antinucleon are neglected. Cross sections are given in graphical form for the reactions and for trsnsitions between eigenstates of isotopic spin. The final-state nucleon-nucleon interaction is shown to have a lnrge effect on the cross sections. The cross section for the reaction pi /sup -/ + p yields p + d is found to be relatively large. At an energy of 10 Mev abcve threshold in the center-of-momentum system the ratio of this cross section to that for pi /sup -/ + p yields p + p + n is about 5: 1. At an energy of 40 Mev above threshold this ratio hns decreased to 1: I. The total cross section for the reaction leading to the unbound final state is calculated by assuming a modified Fermi statistical model. At an energy 100 Mev above threshold, this cross section is approximately 0.1 mb. A theoretical expression for the transition amplitude is developed. (auth)
Date: May 1, 1960
Creator: Hiskes, J. R.

Fission of Gold With 112-Mev C{sup 12} Ions: A Yield-Mass and Charge- Distribution Study

Description: Fission prcduct cross sections were measured radiochemically and mass- spectrometrically for gold bombsrded with 112-Mev C/sup 12/ ions. Cross sections for 43 nuclides were measured for elements from nickel to barium. Thirty-six yields are either primary fission product yields (independent yields) or were corrected (with less than 25% correction) so as to represent independent yields. The independent yields were empirically systematized and a yield-mass curve was constructed. The yield-mass curve is compared with the yield-mass curves obtained from the fission of Bi with 22 and 190-Mev deuterons. The yield systematics indicate that the sum of the mass numbers of complementary fission products is 13 plus or minus 1 amu less tban that of the compound nucleus, and the sum of the charges of complemertary fission products is two units less than that of the compound nucleus. It is postulated that 9 plus or minus 1 neutrons and an alpha particle must have been emitted. Evidence is presented that at least three and possibly more of the neutrons are emitted prior to fission. The most probable charge of the fission products as a function of mass number was determined empirically. It is shown that from mass number 80 to mass number 111 the Equal Charge Displacement (ECD) and Constant Charge Ratio (CCR) rules predict the empirical values equally well. For masses less than 80 and greater than 120 the ECD and CCR rules are shown to be equally poor, as the empirical distribution is between them. The Minimum Potential Energy theory of charge distribution proposed by Present and modified and interpreted by Swiatecki is shown to predict the empirical points over the entire mass region studied (A = 66 to A = 135) within experimental error ( plus or minus 0.2 charge unlt). (auth)
Date: May 23, 1960
Creator: Blann, H. M.

Fractional Crystallization From Melts

Description: S>Studies of the separation process known as zone melting were enclosed in 5 to 10 mm glass tubes and pulled through a stationary heater, which generated a liquid zone. The separation increased as the zone travel rate decreased, as the size of the tube increased, and as the difference in liquid density between the belk solid and the freezing interface increased. It was also found that, for vertical tubes, the separation was much greater when the fluid of lower density Between the buld zone and the freezing interface) was on the bottom the When it was on the top. Insertion of an axial thbe or rod of metal or glass into the zone also increased the separation. A correlation was developed which enables estimation of the separation for various - sithations in zone melting, Equations and principles were developed which enable estimation of the thermal requirements for zone melting and a theoretical study of pure diffusional mass transfer in some melting was also made. A general expression for concentration profiles was derived for materials with a constant distribution coefficient and a method for the rapid estimation of these concentration profiles was developed, Numerical results for eutectic-forming systems were obtained, and summarized in an analytical approximation. Economic calculations are included for a separation in the multistaged semicontinuous zone refiner known as a zone-void refiner. Exploratory experiments were made on a cooled-drum apparatus (modified drum- flaker), using NaC1-water as a system. These indicated that this equipment might be useful for large scalp industrial separations, although further research and development are needed. (auth)
Date: June 1, 1960
Creator: Wilcox, W. R.

Longitudinal Dispersion in Beds of Finely Divided Solids

Description: Experimental determinations of the longitudinal dispersion coefficient and the Peclet number were made for three binary gas systems. The experimental technique involved measuring the dispersion of a step function input to a column packed with glass beads. The diffusional model was employed to obtain the differential equation describing longitudinal dispersion in a packed column. This equation was solved with suitable boundary conditions, and the solution was used in the analysis of the experimental dispersion data. The experimental results show a variation in the Peclet number from 0.1 to 0.6, and in the eddy dispersion coefficient from 0.03 to 1.0 cm/sup 2//sec for the Reynolds number range from 0.03 to 1.0. (auth)
Date: June 1, 1960
Creator: Robinson, J. M.

The Two-Pion Exchange Contribution to the Higher Partial Waves of Nucleon- Nucleon Scattering

Description: By means of the Mandelstam representation, expressions are obtained for the two-pion-exchange contributions to the higher partial waves of N-N scattering. A set of ten invariant amplitudes is selected, of which each member obeys the Mandelstam representation. Dispersion relations are written for the amplitudes in which the discontinuities are absorptive parts for N-bar-N scattering. By means of the unitarity condition the absorptive parts are expressed as a partial- wave expansion in terms of the pi pi - NN partialwave amplitudes of Frazer and Fulco, except for the contributions of the pole in the pi -N system which are treated exactly in order to ensure better convergence of the partial-wave expansion. The N-N transition amplitudes in the angular-momentum representation are expressed in terms of the invariant amplitudes. (auth)
Date: June 1, 1960
Creator: Cziffra, P.

A Mass-Spectrometric Investigation of Sulfur Vapor as a Function of Temperature

Description: A mass-spectrometric investigation was performed on sulfur vapor in equilibrium with the condensed phase at 120 to 210 gas-cooled C. It was found that, in this temperature range, equilibrium sulfur vapor contains appreciable quantities of S/sub 8/, S/sub 7/, S/sub 6/, and S/sub 5/ only. The sulfur vapor emanated as a small well-collimated molecular beam from a specially constructed source into an ionization chamber which was designed to exclude from analysis any sulfur vapor that had impinged on the walls or the hot electron filament. Essential identical ionization potentials were determined for S/sub 8/ , S/sub 7/, S/sub 6/, and S/sub 5/ of 9.8 0.4 ev. The heat of vaporizati on of S/sub 7/ was calculated to be approximately 2.5 kcal greater than that of S/ sub 8/. Upper limits for S/sub 8/ and S/sub 7/ composition in S vapor at 120 gas- cooled C were determined to be 86% and 14%, respectively. It is proposed thst S/sub 8/ is the vaporizing species, that S/sub 7/, S/sub 6/, and S/sub 5/ result from dissociation of S/sub 8/. and that all four molecules have a ring configuration. (auth)
Date: June 15, 1960
Creator: Zietz, M. C.

Analysis of Current Distribution in Electrolytic Cells With Flowing Mercury Cathodes

Description: An idealized model is postulated embodying the essential features of industrial caustic-chlorine cells with horizontal flowing-mercury cathodes. This model is examined in detail, and relations expressing the local anode potential, cathode potential, and ohmic potential drop in the electrolyte in terms of local current density and other parameters are established. These relations are combined to give a system of equations relating current density at any location along the cell to applied total potential and to operating conditions in the cell upstream of the point in question. Numerical solutions of these equations for several cases of cell operating conditions are carried out on a digital computing machine. The effects of changes in operating parameters upon average current density, individual electrode potentials, and current distribution are evaluated. (auth)
Date: July 19, 1960
Creator: Grens, E. A., II

Some X-Ray and Fast Neutron Response Characteristics of Silver Metaphosphate Glass Dosimeters

Description: A study was conducted to determine the adequacy of silver metaphosphate glass as a dosimeter for gamma radiation coexistent with fast neutrons. The fast-neutron response in the energy region encompassing a major pcrtion of the fission spectrum was determined and a method of decreasing the photon-energy dependence was developed. The size of the dosimeter and reprcducibility of results make this system a useful addition to gamma -ray dosimetry. particularly for gamma rays coexistent with neutrons. In some experiments the greatly increased sensitivity to low-energy photons permits accurate measurement of exposure doses as small as a few hundred milliroentgens. (auth)
Date: September 1, 1960
Creator: Thornton, W. T. & Auxier, J. A.

The Magnetic Properties of Deformed Nuclei

Description: It is shown that the magnetic moments of odd-A deformed nuclei can be interpreted in terms of the independentparticle model with interconfigurational mixing due to the very-short-range residual forces. The latter are implied by using the empirically reduced spin gyromagnetic ratios. The effects of these residual forces on the collective gyromagnetic ratios g/sub R/ are discussed in terms of pair correlation. The effect of particle-rotation interaction on the magnetic moment and the collective gyromagnetic ratio are shown. The g/sub R/ values are obtained from the magnetic moments and the matrix elements for M1 transitions in tais band. It is found that these mechanisms give a satisfactory account of the collective gyromagnetic ratio of Dy/sup 161/, Ho /sup 165/, Er/sup 167/, and Hf/sup 179/. (auth)
Date: April 1, 1961
Creator: Chiao, L.

Heavy-Ion Elastic Scattering

Description: The elastic scattering of C/sup 12/ ions from Ar, Fe, Ni, Ag/sup 107/ In, and Ta was measured as a function of angle, at a laboratory-system energy of 124.5 Mev with the Berkeley heavy-ion linear accelerator. The experimental equipment and techniques are discussed. The angular distributions show the same general behavior as previous heavy-ion elastic scattering experiments. The experimental data were analyzed with the semiclassical Blair model as modified by McIntyre. Very good agreement with experiment was obtained. The measurements were taken with 1% statistics in order to study the structure of the angular distributions in greater detail, because only by fitting the details in the structure was it possible to obtdin unambiguous sets of parameters. The parameters indicated a nuclear radius of 1.45A/sup 1/3/ x 10/sup -13/ cm, and a nearly constant surface thick ness of 1.6 x 10/sup -13/ cm. Total reaction cross sections were obtained. A rainbow-model analysis by Goldman of the data is given. Existing alpha - and heavy-ion scattering data were analyzed with the McIntyre model and compared with previous optical-model analyses of the same data. It was found that, by independent analysis, the two models give the same imaginary phase shifts for all partial waves. The real phase shifts are identical above a certain lth partial wave, but differ widely below this 1 value. It is shown that in the region of disagreement the real part of the phase shifts is irrelevant to the calculation of the cross section. (auth)
Date: April 17, 1961
Creator: Alster, Jonas