Astrophysics and Astronomy Commons^™

The Monte Carlo Method Applied To An Estimation Of Delayed Neutron Response, Garland David Turner

Physics & Astronomy ETDs

An experimental program has been undertaken at Los Alamos Scientific Laboratory to study delayed neutron effects. As a part of this program, experiments were conducted with thin disks of various fissionable materials to measure the delayed neutron response to a pulse of high-energy neutrons. In support of the experiments, calculations were made with a computer program which solves the Boltzmann transport equation by finite difference methods. Difficulties with the calculations led to an analysis showing that correct treatment of neutrons moving parallel to the faces of the disk was vital to the success of the calculation. As an extension of …

Cosmic Ray Anisotropy In Interplanetary Space, Jacqueline Hope Ericksen

Physics & Astronomy ETDs

The solar diurnal variation of cosmic ray intensity results from an interaction of cosmic rays with the co-rotating spiral interplanetary magnetic field. Changing interplanetary conditions might therefore be reflected in the diurnal variation. In this dissertation, the dependences of the quiet-day solar diurnal variation on the general level of solar activity and on the interplanetary sector structure are investigated. It is found that the amplitude of the solar diurnal variation as recorded by the Embudo and Bolivia multidirectional underground muon telescopes is significantly smaller near solar minimum (1965) as compared to solar maximum (1968). This amplitude dependence is associated with …

Theoretical Determination Of The Spectroscopic Constants Of The H₂ Ground State, Fun-Min Wu

Physics & Astronomy ETDs

Recently the h2 ground state potential E was calculated in double precision by Kolos and Wolniewicz using a 1oo-term wave function. For this kw potential the coefficients in a power series expansion about the potential minimum re are here determined by using the pure electronic potential and central differences. Resulting Dunham potential coefficients Ao, A1, A2, A3, A4, A5, and A6 are 79703 cm-1, -1.6031, 1.865, -1.999, 2.048, -2.02 and 2.0, respectively. From these coefficients the spectroscopic constants are found to be yoo = 8.36, y10 = 4406.6, y20 = -122.6, y3o = 1.2, y40 = -0.04, yo1, = 60.838, …

A Study Of The Sidereal Diurnal Variations Of Cosmic Rays Underground., Albert Brunsting

Physics & Astronomy ETDs

The sidereal diurnal variation of cosmic rays has been measured using underground (40 m.w.e.) meson telescopes located near Albuquerque, New Mexico (35.20°N, 106.41°w) and at Chacaltaya, Bolivia (16.31°s, 68.15°w). Each ofthe two locations has telescopes which scan the vertical and four inclined directions.

Two and three complete years were used for the tele­scopes at the Bolivia and New Mexico locations respectively. The average solar diurnal variations were calculated for each telescope for each month. Based on these monthly averages, the sidereal diurnal variations were computed. A correction was made in the analysis for any yearly modulation of the solar diunal …

A Shock Tube Study Of Recombination In The Lean Hydrogen-Oxygen Reaction Based On The Infrared Emission From Water Vapor, Larry S. Blair

Physics & Astronomy ETDs

ABSTRACT

Recombination in the hydrogen-oxygen reaction has been studied by monitoring the growth of infrared emission at 2.7 microns from water vapor as it is formed behind incident shock waves. Experiments were carried out in gas mixtures with hydrogen-to-oxygen ratios between 1.0 and 0.33 and temperatures between 1435° and 1868°K. Reactants were diluted with 92-98% argon. The validity of the transparent gas approxi­mation (emission intensity proportional to (H20]) and the relationship between emission intensity and temperature were established by cali­bration experiments in which mixtures of water vapor and argon were shock-heated to temperatures between 1328° and 1982°K. Analysis of H20-emission …

Meteorological Effects On Cosmic Rays At Albuquerque, New Mexico., David Nason Glidden

Physics & Astronomy ETDs

Ground-based observations of cosmic-ray intensity have the disadvantage of being more sensitive to variations of atmospheric temperature and pressure than to the more interesting variations in the primary cosmic radiation. It is, therefore, imperative to correct the recorded cosmic-ray intensity for variations of atmospheric origin before studies can be made of the smaller variations of the primary cosmic ray intensity.

In this thesis an attempt has been made to remove the variations of atmospheric origin from the cosmic-ray intensity recorded simultaneously by a neutron monitor and a meson telescope located at Albuquerque, New Mexico. It was found that the neutron …

Geophysical Institute Annual Report 1968-69, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1968–69 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Theoretical Analysis Of The Vibrations And Rotations Of The B¹[Sigma][Mu] State Of The Hydrogen Molecule, Sandra Zink Moody

Physics & Astronomy ETDs

Theoretical calculations of the rotational-vibrational constants of the B¹Σ⁺_u state of H₂ were made using the Dunham analysis and by fitting equations to energy eigenvalues. The potential energy function for the nuclei used in the calculations was computed by W. Kolos and L. Wolniewicz using the variational technique. The power series used in the Dunham analysis made use of Stirling's central difference interpolation polynomial. The equilibrium separation R_e found from the Born-Oppenheimer potential is 2. 42916₅ atomic units, differing from the Kolos-Wolniewicz value of 2.4288. Adiabatic corrections were taken into account through a …

New Solutions Of The Einstein-Maxwell Equations From Old, B. Kent Harrison

Faculty Publications

Methods are discussed with which one may derive theorems which allow one to generate new solutions of the Einstein-Maxwell equations from old ones. The old solutions used to generate new ones must admit at least one nonnull Killing vector and may be required to satisfy other conditions, depending on the theorem derived. Examples of derivable theorems are shown; these theorems are used in turn to show how generation of new solutions is accomplished. Examples of the latter are shown, such as generation of Brill or electrified NUT space from the Schwarzschild solution, generation of a new twisted Melvin universe from …

Response Prediction For The Oso-G Satellite Solar Neutron Instrument By Matrix Methods., John Coalmer Conklin

Physics & Astronomy ETDs

Properties of the University of New Mexico’s solar neutron instrument for use on the NASA 0S0-C satellite were investigated. A sensor model was developed by use of two computer codes. First, the total efficiency of the converters was calculated by a simulation code with a resulting total efficiency at 100 Mev of approximately two per cent of which four-fifths was carbon recoil contribution.

Second, geometry properties of the instrument were provided by a Monte Carlo program, with maximum geometry efficiency equaling about fourteen per cent. These were combined to give a total response profile for the instrument which was expressed …

A Study Of The (T, P) Reaction On 90,92,94,96zr And 122,124sn, Jerome G. Beery

Physics & Astronomy ETDs

A study is made of the (t, p) reaction on targets of ^90,92,94,96Zr and ^122,124Sn. The purpose of the study is to investigate the nuclear energy levels that are populated by putting two neutrons into a target nucleus. The targets were bombarded with 20-MeV tritons from the Los Alamos tandem Van de Graaff facility. Protons were detected with solid-state counter telescope and the data was recorded with an online digital computer. Energy spectra were taken for each of the targets utilizing a magnetic spectrometer in order to obtain excitation energies with an accuracy of ± 10 keV. The …

The Motion Of A Charged Particle In The Field Of A Magnetic Dipole, E. Royce Fletcher

Physics & Astronomy ETDs

The principal difficulties encountered in attempting to solve the general problem of the motion of a non-relativistic, non-radiating charged particle in a magnetic field which varies position and time, are associated with the induced electric field. That is to say, the time variation of the magnetic field produces an electric field which also acts on the particle. Both these fields must be known as functions of time and position if the equations of motion are to be determined exactly.

The Spectroscopic Constants Of The Ground Electronic State Of Hydrogen Molecular Ion, Bertle Daniel Hansen

Physics & Astronomy ETDs

ABSTRACT

An accurate theoretical determination of certain vibration rotation properties of the hydrogen molecular ion is made. Two different methods of analysis are used in the determination of these properties. First, an energy equation for diatomic molecules is

fitted directly to theoretical vibration and rotation eigenenergies of the ground electronic state of H+2 calculated by J.M. Peek. These eigenenergies include adiabatic corrections determined by w.Kolos. Second, a fixed-nucleus potential for the ground electronic state of H+2, calculated by J. M. Peek which did not include adiabatic corrections, is expanded in a power series in the neighborhood of the equilibrium internuclear …

Pressure And Temperature Dependence Of The Acoustic Velocities In Polymethylmethacrylate, James Russell Asay

Physics & Astronomy ETDs

The acoustic velocities in polymethylmethacrylate have been measured with an ultrasonic pulse echo technique as functions of frequency, temperature and pressure. At atmospheric pressure, data on the velocities and attenuation coefficients were obtained over the range of temperature from 22°c to 75°c and for the frequency range of 6 to 30 MHz. At the temperatures of 25, 40, 55 and 75°c, the pressure dependence of the longitudinal and shear velocity was obtained to 150,000 psi at a frequency of 6 MHz. From the frequency measurements of the velocities, the complex elastic moduli in polyrnethylmethacrylate were calculated at room temperature. The …

Dose And Depth Dose Measurements On The Sixth Gemini Flight, A Comparison With The Gemini-4 Radiation Measurements, Marion F. Schneider

Physics & Astronomy ETDs

Two tissue-equivalent ionization chambers were flown behind 0.4 gram/cm.² and 2.5 grams/cm.² of shielding inside the Gemini-6 spacecraft. The instruments measured the radiation levels resulting from primary cosmic radiation and the trapped particle environment of the earth's Van Allen belts. Each sensor was constructed from a special tissue-equivalent plastic with radiation cross sections that closely match standard muscle tissue for the many complex types and energies of radiation encountered in space. The design of the sensor and logarithmic electrometer preamplifier are described in detail. The calibration and directional sensitivity of the sensors with cobalt-60 and cesium-137 gamma radiation …

Surface Resonances In High Frequency Scattering From A Nearly-Sharp Three Dimensional Well., Jaime Marcelo Wong Luy Tay

Physics & Astronomy ETDs

A computational investigation of the effect of a surface transition region of relative half-width δ on certain surface resonances in high frequencies scattering from a nearly-sharp, three dimensional spherical well is performed by the method of partial wave analysis.

An incident beam of particles, described by a scalar plane wave, interacts with a fixed scattering center represented by a dielectric sphere of index of refraction 1.333, with a very small transition region in the boundary of the well, described by an odd polynomial function of third order. This is the scalar-wave analogue to the more complicated problem of scattering of …

The Red Leak And Its Effect In Ultraviolet Photometry., Jeffrey David Colvin

Physics & Astronomy ETDs

The red leak in the red 􀀉and of the ultraviolet filter (Corning #9863) of the standard UBV photometric system is investigated. Astronomical photometry is discussed in general, and UBV photometry in particular. The photometric system used in this work is also discussed, including telescope, phototube, filters, and amplifier. The standard filters of the UBV system are used, but the standard phototube of this system is not used. An analytic representation of the red leak magnitude correction is developed.

Sixty-five measurements were made for a wide variety of stars from spectral class B3 to spectral class M2. The red leak correction …

A Method For Measuring Magnetization To High Pressures, C. R. Johansen, Mark H. Nelson, J. H. Gardner

Faculty Publications

A partially successful attempt has been made to measure the magnetic moment per unit volume of ferromagnetic materials as a function of pressure to the 100-kbar region. The apparatus, an early version of which has been described previously, consists basically of two opposed Bridgman flat anvils of alumina. One anvil also acts as a dielectric-filled microwave resonant cavity for an x-band spectrometer, allowing electron spin resonance studies to be made to high pressure. The sample to be studied is placed in contact with the anvil-cavity and covered with a pressure-transmitting medium which in turn is encircled by a flat pyrophyllite …

Geophysical Institute Annual Report 1967-68, University Of Alaska Fairbanks. Geophysical Institute

GI Reports

The 1967–68 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Very High Pressure Effects Upon The Epr Spectrum Of Ruby, H. Mark Nelson, D. B. Larson, J. H. Gardner

Faculty Publications

The variation in the electron paramagnetic resonance (EPR) spectrum of ruby as a function of pressure has been observed to beyond 70 kbar for a magnetic field orientation parallel to the crystalline c axis. The data can be interpreted in terms of the usual spin Hamiltonian, where the spectroscopic splitting factor g|| has the same value as at ambient pressures, but where the zero-field splitting deltaincreases in a linear fashion from 0.38 to 0.43 cm. The experimental apparatus has been described previously, although important improvements in the pressure seal and in the pressure calibration have been made and are described …

The Kinetics Of Phase Transitions In Solid Cyclohexanol And Related Plastic Crystals., William Thomas Griffith

Physics & Astronomy ETDs

The phase relations and the kinetics of phase transitions in the solid -forms of cyclohexanol, cyclohexanone, chlorocyclohexane, bromocyclohexane, and cyclopentanol have been investigated. Cyclohexanol has been studied the most thoroughly; the other compounds have been considered largely for purposes of comparison with cyclohexanol. The primary methods of investigation have been the measurement of dielectric properties and visual observations. The transitions in cyclohexanol have also been followed photographically in order to measure the growth velocities of the phase interfaces.

A Study Of The Backscatter Of Light From A Single Water Droplet, Theodore Stauffer Fahlen

Physics & Astronomy ETDs

The backscattered light from a single water drop is studied theoretically and experimentally for drop diameters of about one millimeter. G. Mie gave the exact mathematical solution to the problem of an infinite, plane, monochromatic, electromagnetic wave scattered from a perfect sphere of any radius and index of refraction in 1908. The results of this theory are applied to drops of size parameter (defined as the ratio of the drop circumference to the wavelength of the incident light) near 3000; this corresponds to a drop diameter of about one millimeter. Theoretically, it is shown that the backscattered light originates from …

Rocket Probe Measurement Of Electron Energy Spectra In The Earth's Radiation Belts, Donald Stuart Robb

Physics & Astronomy ETDs

No abstract provided.

Nuclear Quadrupole Relaxation., Derwin F. Brown

Physics & Astronomy ETDs

A nucleus with an asymmetric charge distribution (an asymmetric arrangement of protons) exhibits a quadrupole moment which interacts with the gradient of the electric field of the surrounding electrons. The interaction energy is a function of the angle between the nuclear spin axis and the axis of the surrounding electric field. The nucleus processes about the electric field axis in quantized energy states. These quantized energy states correspond to a hyperfine splitting simi­lar to the hyperfine structure of the magnetic dipole-dipole interaction between the nucleus and the electrons. The application of an external electric field, oscillating at the processional frequency …

An Introduction To The Fundamentals Of Radiation Transport Theory., William A. Proctor

Physics & Astronomy ETDs

I first became interested in radiation transport theory when, in August 1966, I was given primary responsibility for a large computer program which serves as a tool for solving high temperature, time dependent, radiation-hydrodynamics problems. Inquiries as to where to start learning about this subject invariably resulted in my being directed to the two books by Chandrasekhar (1957 and 1960) and the book by Kourganoff (1963). From the beginning of my study of these expositions, I found it rather curious that a theory which treated the radiation field as continuously distributed in space was formulated in a manner which appeared …

Measurements Of Solar X-Ray Emission From The Ions Carbon Vi And Nitrogen Vii, Winifred Doyle Evans

Physics & Astronomy ETDs

Studies of the solar spectrum in the extreme ultraviolet and x-ray region have been possible since sounding rockets and satellites have been available to carry instruments above the earth's atmosphere. Progress was slow at first, but techniques have improved rapidly in recent years and a considerable body of experimental data has been accumulated since the first rocket flights in the late 1940’s.

Step-Wise Variation Of Spectrometer Quench Rates For Nuclear Quadrupole Resonance Measurements, Curtis M. Wise

Physics & Astronomy ETDs

In nuclear quadrupole resonance (NQR) it is desirable to better examine the magnitude of the resonance signals. This thesis describes the construction and testing of spectrometer control circuits which enable one to better examine a single resonance signal to the near exclusion of extraneous resonance side band responses and circuit noise in the NQR detection apparatus. Added to the basic spectrometer circuit is a step-wise varying quench rate control. For each adjustment of this control other control units are activated to keep the chosen NQR signal fixed in position and in magnitude within the spectrometer's span of detected radio frequencies. …

Analysis Of Particle Counting Rate Variations Observed On Satellite Oso-B2, Esther Y. Ma

Physics & Astronomy ETDs

The ommidirectional cosmic ray fluxes at an altitude of 300 miles and within ± 34 degrees latitude were studied using two Cerenkov counters and a scintillation counter aboard the 0S0-82 Satellite. The fluxes were found to depend strongly on the geomagnetic field with the trapped particles in the South Atlantic Radiation Anomaly being directional in some locations.

²⁰⁷Pb (N, N') ²⁰⁷Pbm And ²⁰⁸Pb (N, 2n) ²⁰⁷Pbm Cross Sections, Edward Raymond Shunk

Physics & Astronomy ETDs

The cross sections for the production of the ²⁰⁷Pb^m state from ²⁰⁷Pb(n, n') and ²⁰⁸Pb(n, 2n) have been measured from the threshold through 14 MeV by observing the 1 .064 MeV gamma ray in the decay of ²⁰⁷Pb^m (T _½ = 0.818 ± 0.004 sec) with a 3 in. x 3 in. NaI (T1) detector. Separated lead isotopes were irradiated for 4 sec and pneumatically transported to the detector. A 400-channel analyzer a used a time analyzer to record counts from neutron monitor during the irradiation and from the detector after the irradiation. These …

The 233u Fission And Capture Cross Sections And Their Analysis At Low Engines, Delmar W. Bergen

Physics & Astronomy ETDs

The ²³³U fission and capture cross sections were measured using a nuclear-device neutron source and time-­of-flight techniques. Cross section data are presented from 20 to 10⁶ eV for fission and from 20 to 63 eV for fission + capture. The resonance region (20 eV to 63 eV) was fitted with both a single level function consisting of a sum of Breit-Wigner levels and the Reich and Moore multilevel function based on R matrix theory. The resulting resonance parameters are listed and discussed. In order to establish the validity of the resonance parameters derived from the multilevel fit, a …