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Disintegration of Helium by 300-Mev Neutrons

Description: An investigation of the inelastic and elastic reactions between high- energy neutrons nnd He nuclei was conducted with a cloud chamber filled with He and operating in a pulsed magnetic field of 21,700 gauss. Neutrons produced by bombardment of a 1/2-in. LiD target with 340-Mev protons in the 184-in. synchrocyclotron were collimated and passed through the 22-inch expansion cloud chamber, which was filled with He gas to a total pressure of 89.8 cm Hg. Exclusive of meson-producing reactions, the possible reactions are: Inelastic, He/ sup 4/(n,pn)t, He/sup 4/(n,d)t, He/sup 4/(n,2np)d, He/sup 4/(n, dn)d, He/sup 4/ (n,2n2p) n, He/sup 4/(n, 2n) He/s up 3/; and Elastic, He/sup 4/(n,n)He/sup 4/. The total number of events, for incident neutrons above 160 Mev, was normalized to the interpolated n-He/sup 4/ total cross section at 300 Mev, and absolute cross sections for the various processes were established. Energy and angular distributions of the reaction products were compared with available theoretical predictions and other experiments. A few cases of meson production were noted. (auth)
Date: November 1, 1957
Creator: Innes, William H.
Partner: UNT Libraries Government Documents Department

The Kinetics of the Complexing of Ferric Ion by Thiocyanate and Chloride Ions

Description: An apparatus for rapidly mixing two solutions and recording the light absorption, which was developed by Connick and Below, has been modified. The mixing characteristics were studied and models were developed in an attempt to umder stand the observed mixing phenomena. The apparatus was applied to a study of the kinetics of the reactions Fe/sup +++/ + SCN/sup -/ = FeSCN/sup ++/ and Fe/ sup +++/ Cl/sup -/ = FeCl/sup ++/ in aqueous solution, with both reactions having the forward rate law STAd(FeX/sup ++/)/dt = k/sub 1/ (Fe/sup +++/) (X/sup -/) + k/ sub 2/ (Fe/sup +++/)(X/sup -/)/(H/sup +)!, where X/sup -/ represents either SC N/ sup -/ or Cl/sup -/. The rate constants k/sub 1/ and k/sub 2/ have been measured as a function of temperature, and the heats and entropies of activation have been calculated. Mechanisms for the observed rate law have been discussed and the entropies of activation were compared with those for analogous reaction rates and with some equilibrium entropies of complexing. A rate for chloride complexing of ferric ion was obtained from nuclear magnetic resonance studies and compared with the results of the spectrophotometric kinetic study. (auth)
Date: December 1, 1957
Creator: Coppel, Claude Peter
Partner: UNT Libraries Government Documents Department

Measurement of Beam Current in the Bevatron by Induced Voltages

Description: The Bevatron uses a system of electrodes through which the internal proton beam passes in order to continuously measure the magnitude and radial position of the beam. The bunched circulating beam induces a periodic voltage on the electrodes. This signal is amplified and displayed on an oscilloscope and also converted to direct current for operation of a recorder. Two types of electrode systems are used. The first is a large hollow box to provide beam magnitude signals for specialized monitoring and for primary calibration. The second system consists of two sets of smaller electrodes. One set provides beam radial-position information for tracking control, and the other provides beam magnitude information for magnitude control and for general distribution to experimenters associated with the Bevatron. A telemetering radio link is used to relay beam information to those in other areas. Problems associated with handling the beam signal are discussed, and the design principles involved in detection, amplification, and isolation of the signal are described. Calibration techniques, signal distribution facilities, and control features are also given. The systems described are stable and provide the desired information with a minimum of maintenance and operational difficulty. (auth)
Date: October 28, 1957
Creator: Lavrischeff, J. T.
Partner: UNT Libraries Government Documents Department

Studies Relating to the Structure of Aluminum Hydride

Description: The object of the work was to determine the molecular structure of AlH/ sub 3/, using the techniques of nuclear spin resonance.'' Attempts to prepare ether-free AlH/sub 3/ that were unsuccessful are described. Also it was not possible to observe the deuterium signal in AlH/sub 3/. It was possible, by the use of the proton signal of the ether in AlH/sub 3/, to obtain the nuclear spin resonance absorption curve for AlH/sub 3/ by subtracting out the contributions of the ether protons to the resonance signai. A model is proposed to explain the features of the nuclear spin resonance absorption curve. The existence of LiAl/ sub 2/H/sub 7/, which has been postulated elsewhere, is assumed in order to explain the datu obtained from high-resolution nuclear spin resonance experimeats. (auth)
Date: December 16, 1957
Creator: Nickerson, R. F.
Partner: UNT Libraries Government Documents Department

Thermodynamic Properties of Nonstoichiometric Nickel Tellurides and of Tellurium

Description: As part of a thermodynamic study of NiTe and NiTe/sub 2/, an attempt was made to gather data which would determine zero-point entropies as a function of composition. Part of the necessary data have been gathered, and in addition a number of other pertinent or interesting properties of the nickel tellurides, and of Te, have been investigated. Specific heats from 4 to 350 deg K have been measured on NiTe/sub 1.1/ NiTe/sub 1.5/, and NiTe/sub 2.0/, and the thermodynamic functions of these and all intermediate compositions may be considered accurately known over this temperature range. The method employed was conventional precise adiabatic calorimetry in an existing apparatus. The melting point of Te has been redetermined and the highly discordant literature critically reexamined; the triple point may now be stated with some confidence to be 449.7 plus or minus 0.2 deg C. The dissociation pressures of compositions from NiTe/sub 1.5/ to NiTe/ sub 2.0/ have been accurately measured at temperatures up to 780 deg C in order to determine the partial molal free energies and entropies of Te in these compounds. These measurements have incidentally elucidated the phase behavior in the Te-rich region, showing a high solubility of Ni in liquid Te at elevated temperatures, and incongruent melting of the solid solutions such that Te-rich solid solutions are unstable at elevated temperatures. By extrapolation, the boiling point of Te is computed to be 993.6 plus or minus 2 deg C. and the heat of vaporization to be 33,850-908 t cal/mole (one mole equals two gram-atoms). with an accuracy of plus or minus several hundred calories, from the triple point to t = 850 deg , or perhaps 950 deg C. This figure may be considered more accurate, though stated with less precision, than those of previous investigators. (auth)
Date: January 1, 1957
Creator: Machol, R. E.
Partner: UNT Libraries Government Documents Department