Astrophysics and Astronomy Commons^™

Energy And Angular Distribution Of Neutrons From Proton-Proton Inelastic Scattering At 800 Mev, Ted Dean Rupp

Physics & Astronomy ETDs

The neutron energy spectra from the reaction p + p → n + p + π⁺ for an incident proton energy of 800 MeV was measured for all phase space. ++ The channels were dominated by △⁺⁺. (1232) resonance and had a total cross section of 16 ± 1.5 mb. Also, the data demonstrated the dominance of Sand P waves. The experimental results were compared to isobar, phase space and a one pion exchange model. The isobar and phase space models failed to predict the experimental results; however, the one pion exchange model fit the data for …

Polynomial And Rational Fraction Representations Of A Diatomic Molecular Potential, Paul R. Findley

Physics & Astronomy ETDs

A method is presented for approximating a diatomic molecular vibrational potential by fitting to modified forms of the potential. Power's numerical Born-Oppenheimer potential for the H₂⁺ electronic ground state is the potential used in this thesis. The modification procedure is to multiply the potential by various powers of the internuclear separation. This removes the troublesome Coulomb pole at zero internuclear separation. Graphs of the modified forms are presented. Polynomials were fitted directly to the potential, to the modified forms, and to the pure electronic energy. Comparisons are made among the various representations of the potential obtained from the …

Precipitation Phenomena In Antimony-Implanted Aluminium, Richard Allen Kant

Physics & Astronomy ETDs

An experimental and theoretical study of the influence of temperature flux, and fluence on the formation and evolution of compounds formed by ion implantation has been conducted. Transmission electron microscopy was used to determine the size distribution of AJSb precipitates resulting from implanting single crystal A1 with Sb. In addition, the role of ion damage was investigated using both Ar and Al bombardment. These experiments show that for samples which initially contain no Sb, the number density of pre• cipitates decreases with increasing fluence and temperature, and with decreasing flux.

Measurement Of The H- Photodetachment Cross Section In The Continuum Region From 1.5 To 10.5 Ev, Mohammad Hassan Sharifian-Attar

Physics & Astronomy ETDs

We have measured the H photodetachment cross section in the photon energy range from 1.5 to 10.5 eV, using a colliding beam method. The H beam with an energy of 800 MeV, at Los Alamos Linear Accelerator, was intersected by a nitrogen laser beam with a photon energy of 3 .678 eV in the lab frame. We changed the energy of the pho"ton in the H rest frame, through the Doppler effect, by varying the angle between the laser and the H beams. The magnitude of the Doppler shift was enough to cover the entire range from 1.5 to 10.5 …

Neutron-Proton Elastic Scattering At 790 Mev, Roger Daniel Carlini

Physics & Astronomy ETDs

The forward n-p differential cross-section is measured at 790 Mev from 9.5 to 60. degrees in the center of mass. The systematic errors are less than 4.0%. The differential cross-section is parameterized by the function dσ/dΩ = A e^bt, where t is the momentum transfer between the incoming and outgoing neutrons in (GeV/C)², and A and b are constants having the values A= 9.757±.069, b= 5.052±.045. With 36 data points the x² is 55. The magnitude of the ratio of the real to imaginary part of the forward scattering amplitude is found to be .3501±.14.

Convection In Pulsating Stars, Michael John Robert Costello

Physics & Astronomy ETDs

Stellar models using mixing length convection in a linear calculation show a red edge to the instability strip. The models are of a 6 solar mass, 1 x 10 ergs/sec luminos­ity, King 4A composition, cepheid variable star, for various values of effective temperature, Te, and mixing length parameter, a. Results are obtained with an assumed instantaneous adjustment of the convective flux to changes in the local stellar conditions. Calculations of the convective time de­lay show it to be small compared to the period, under the assumption that the convective time delay is due solely to the inertia of convective bubbles. …

The Use Of Nuclear Reactions And Sims For Quantitative Depth Profiling Of Hydrogen In Amorphous Silicon, David D. Allred, G. J. Clark, C. W. White, B. R. Appleton, C. W. Magee, D. E. Carlson

Faculty Publications

Depth profiles for hydrogen in amorphous silicon have been determined by the use of resonant nuclear reactions [1H(15N,αγ)12C and 1H(19F,αγ)16O] and by secondary ion mass spectroscopy (SIMS). Independent calibration procedures were used for the two techniques. Measurements were made on the same amorphous silicon film to provide a direct comparison of the two hydrogen analysis techniques. The hydrogen concentration in the bulk of the film was determined to be about 9 at % H. The SIMS results agree with the resonant nuclear reaction results to within 10%, which demonstrates that quantitative hydrogen depth profiles can be obtained by SIMS analysis …

Heights Of Formation For Certain Solar Spectral Lines, Erik J. Schwendeman

Physics & Astronomy ETDs

Heights of formation are calculated for several of the solar spectral lines studied by the National Aeronautics and Space Administration - Goddard Space Flight Center (NASA-GSFC) New Mexico Solar Station at Sacramento Peak Observatory. These lines are Ca II H, K, 8498 Å and 8542 Å, MgI b₁, NaI D₁ and D₂ and Sil 4103 Å. I calculate the heights of formation for each of these lines along with upper and lower confidence limits representing the height region where 90% of the total intensity of the line is formed in the solar photosphere and chromosphere. The …

A Covariant Approach To Wave Equations In General Relativity, Alan L. Dudley

Physics & Astronomy ETDs

A formalism for the manipulation of tensors in both real and complex spacetimes is introduced, which utilizes the irreducible representations of the Lorentz group to substantially simplify certain general relativistic calculations. The notation is completely covariant and is most effective for massless field calculations. Results emerge which eliminate the majority of the algebraic burden of the traditional Newman­Penrose formalism and, simultaneously, allow the reader to understand both the physical and geometrical meanings of each step of the derivations. The technique developed is well suited for perturbation analyses. Consequently, the perturbed wave equations for massless fields are examined. The notation has …

Infrared Observations Of Hii Regions And Comet West, Paul A. Heckert

Physics & Astronomy ETDs

In Chapter 1, I outline the methods of making ground-based infrared observations. I concentrate on the observational procedures rather than the instrumental design. Near-infrared observations of S 156A, _S 158A, S 159A, S 162A₁, S 228, and G 45. 5 + 0 .1 (#2) made with a beam size of ̴1 are used to estimate the total near infrared flux. After correcting for the line of sight extinction the near infrared luminosities are greater than the Lyman-α luminosities inferred from radio observations. A strong double peaked infrared source was discovered near the region of G 25.3-0.1. The infrared …

Plasma Sheath Analysis By Computer Simulation, Leo J. Rahal

Physics & Astronomy ETDs

The time development of a fully ionized, dense two-component plasma is investigated through the use of a one-dimensional particle simulation code. The plasma is initially composed of two distinct regions. One region is a uniform plasma in which electrons and ions are at the sane temperature and have no electric fields due to charge separ­ation. The other region contains a charge separation of electrons and ions resulting in an electric field. There also exists an electron current which produces a confining magnetic field. This is the sheath region between the neutral plasma and the confining magnetic field. The simulation occurs …

Theoretical Studies Of Nucleic Acid Sugar Ring Analogs, Ali-Reza Hashemi-Attar

Physics & Astronomy ETDs

Extended Hueckel theory (EHT) was used to study analogs of sugar rings in nucleic acid monomers. The energy gradient in a variable metric algorithm was used to find the potential energy along the pseudorotation path. Use of the energy gradient made it possible to permit 34 degrees of freedom in a molecule. Seven molecules and their isomers were studied. These were: 3-hydroxy2-methyl tetrahydrofuran, 2-ami no-4-hydroxytetrahydrofiJran, 5-ami no3-hydroxy-2-methyltetrahydrofuran (deoxyribonucleic acid analog), 3,4-dihydroxy-2-methyltetrahydrofuran, 2-amino-3,4-dihydroxytetrahydrofuran, 2-amino-5-methyltetrahydrofuran, and 2-amino-3,4-dihydroxy-5-methyltetrahydrofuran (ribonucleic acid analog).

It was shown that the difference in sum of total overlap populations (TOP) for all pairs of atoms between two related conformations …

The Nitrogen Dayglow On Mars, Jane L. Fox, Alexander Dalgarno, E. R. Constantinides, G. A. Victor

Physics Faculty Publications

The ultraviolet dayglow spectrum arising from emission of N₂ in the Mars atmosphere is predicted. The intensities are such that a high-resolution spectrum should readily reveal the presence of N₂ at the abundances suggested by the Viking experiments.

Computer Model Of A Fast Toroidal Plasma Compression, With Application To The Topolotron, H. Mark Nelson, Keith H. Brown, Charles A. Hart

Faculty Publications

The method is developed for a comuputer sequence which models a fast toroidal theta or screw pinch for a highly conducting axially symmetric plasma. The computer sequence takes into account the self-inductances of the plasma and the external conductors which drive the compression as well as the mutual inductance which electromagnetically couples the two. The computer sequence is divided into three phases: a snowplow compression phase, an adiabatic compression phase, and a crowbarred circuit phase. The computer sequence is applied to a topolotron and an example is given of a magnetohydrodynamic equilibrium geometry for which the plasma surface possesses an …

Behavior Of A Manganin Coil At Elevated Temperatures And Pressures, Jonathan D. Weiss, Daniel L. Decker, H. B. Vanfleet

Faculty Publications

We have determined the temperature dependence in the first-order pressure coefficient of a manganin coil to be dBetaB/dT= (4.2±0.8) ×10^-7 (kbar degrees C)^-1 in the equation R (T,P) =R (T,0)(1+BetaP+GammaP2), where R (T,P) is the coil resistance at temperature T and pressure P. The measurements were performed by simultaneously measuring the coil resistance and temperature at the transitions of mercury and bismuth, which were observed by differential thermal analysis.

Neutron Spectra At Zero Degrees From Proton Bombardment Of Light Nuclei At Medium Energies, Constantine George Cassapakis

Physics & Astronomy ETDs

The neutron-momentum spectra at 0° resulting from proton bombardment of 9Be, 12C, and 27Al at Tp=633MeV, and those of 12C and 27Al at Tp=786 MeV, have been measured at the LAMPF (Los Alamos Meson Physics Facility)-Nucleon Physics Laboratory.

The measurements utilized the recently developed single arm, multiwire proportional counter, recoil-proton, magnetic spectrometer. I

dentification of the recoil charged particles was achieved through momentum analysis and simultaneous time­of-flight determination for each particle constituting a valid event.

The momentum and energy resolutions achieved are about 1% and 1.4%, respectively, at the incident proton energies considered.

The spectra for 9Be and 27Al exhibit …

Sensitivity Of A Gas Filter Correlation Instrument To Variations In Atmospheric Profile And Earth Surface Temperatures, Joseph C. Casas

Physics Theses & Dissertations

The Gas Filter Correlation Radiometer Analyzer (GFCR), in application to the remote sensing of trace gases in the atmosphere, is potentially limited by the sensitivity of the measured upwelling thermal radiation to surface temperature and atmospheric temperature conditions. This study has been carried out to examine the principles of operation of the GFCR Analyzer and to obtain quantitative estimates of the errors produced in GFCR Analyzer measurements of CO (4.6μ), S02 (8.6μ), NH3 (11.0μ), and CH4 (8.1μ) resulting from uncertainties in the atmospheric temperature profile and ground temperature.

A simple mathematical prototype GFCR Analyzer was assumed. A line-by-line atmospheric radiative …

The Determination Of Double Mode Variable Star Periods, Arne A. Henden

Physics & Astronomy ETDs

ABSTRACT

The problem of determining the periods of objects oscillating in one or more modes is discussed. Although the methods described are applicable to many different kinds of objects and observations, the discussion has been limited to double mode Cepheid stars.

Two methods of solution are followed in detail. An autocorrela­tion technique based on the scatter of points in an amplitude-phase plane is used for most cases. A means of calculating smoothed mean curves is discussed. A Fourier transform method is presented for closely spaced data points, with prewhitening included for accurate secondary period and amplitude determinations.

Three test problems …

A Satellite Study Of The High Energy Proton Environment Under The Radiation Belt, Kailash Chandra Dhingra

Physics & Astronomy ETDs

Proton data outside of the South Atlantic Radiation anomaly (in the regions where h_min < 0) from the University of New Mexico High Energy Neutron and Proton Detector aboard OSO-6 satellite were analyzed in the present work. The detector was useful in the energy range from 75-145 Mev and the data were obtained during the period from August 1969 to January 1971. The altitude of the satellite varied from about 480 Km to 580 Km. Since the observed proton flux resulted from different source mechanisms a procedure was developed that allowed us to compute and separate the contributions made by different mechanisms in the observed protons. New evidence was derived from the study of the Down-Up asymmetry both along the field direction and the zenith of the look direction (ZAP angle) which substantiated the hypothesis that either one or both of the processes of the radial and the pitch angle diffusion play active roles in the origin and the distributions of the protons in the inner radiation belt. It was argued that processes drive the trapped protons in the radiation belt into the regions where stable trapping is not possible and thus contribute to the observed protons in these regions. We were further able to compute the total diffusing flux; however, it was assumed that both the Splash and the Re-entrant albedo proton fluxes were equal. Since this assumption was not very accurate, an incorrect estimation of the diffusing proton flux might have resulted. In addition to the above, the flux and the energy spectrum of the albedo protons were derived at three different regions. These were then compared with the results of other investigators. Discrepencies in both the flux and the energy spectrum were observed. Our flux value of 1.05 protons/m² -sec-ster-Mev for the Re-entrant albedo at an energy of 85 Mev in the region where L = 2.5 was about a factor of two and a half higher than estimated by Ray (1967). No west-east asymmetry was observed in the true proton flux (proton flux obtained by subtracting the background contamination from the observed proton flux), within the limits of the experimental error. Since such an asymmetry was expected if we assume that the albedo protons alone constitute the true protons, it was concluded …

A Theoretical Study Of The Predissociation Of The O2 B 3Ʃu- Electronic State, Richard Allan Harris

Physics & Astronomy ETDs

It has been known for many decades that the B 3Ʃ_u^- state of the oxygen molecule, the upper state of the Schumann-Runge electronic band system, is predissociated. The predissociation has been attributed to the 3Π_u state, arising from the ground state, separated atom, manifold of molecular states, by previous investigators with the crossing point of the potential energy curves ranging from somewhere on the inner limb to somewhere on the outer limb of the bound excited B 3Ʃ_u^- state. This research has been undertaken to quantitatively describe the observed predissociation. A model with adjustable parameters …

Pi-Meson Absorption On The Deuteron, Bruce Goplen

Physics & Astronomy ETDs

The nonradiative absorption of positive pi-mesons by deuterons is studied within the framework of Lagrangian formalism and the impulse approximation. The pi-nucleon absorption interaction is taken to be pseudovector; however, the reaction is believed to be dominated by pi­nucleon scattering. Thus, the main thrust of the investigation is directed at three different approaches to the scattering interaction. First, the Hamiltonian formalism of Koltun and Reitan is extended to include energetic pions. An off-shell form is chosen for p-wave scattering which at low energy reduces to the field-theoretical result of Klein. In the second approach, the S-matrix formalism of Lazard, Ballot …

General Geodesic Motion In The Extended Kerr Manifold, Richard H. St. John

Physics & Astronomy ETDs

The timelike and null geodesics in the Kerr metric describe important properties of the space surrounding a rotating black hole. The general characteristics of these geodesics, with an emphasis on those on the axis of symmetry and the equatorial plane, are found in this paper. On the axis of symmetry, the behavior of all timelike and null geodesics is completely described. The accessibility of various spaces added for geodesic completeness in the extended manifold is found by making local observations of geodesics in one coordinate patch from geodesics in another. The analysis on the equatorial plane shows that for a …

Ultraviolet Photosimulated Thermoluminescence Of Lithium Flouride, Martin Payne

Masters Theses & Specialist Projects

TLD-100 (lithium fluoride) thermoluminescence dosimeters are widely employed for the detection of ionizing radiations. This paper shows that these dosimeters may also serve as practical germicidal ultraviolet radiation dosimeters. To measure ultraviolet radiation, the TLD-100 dosimeters are first exposed to 500,000 roentgens of gamma radiation and then annealed at 300°C. Subsequent dosage of ultraviolet radiation may be determined by observation of photostimulated thermoluminescence of the crystal. The presented data indicate that the thermoluminescence response is linear for exposures up to 6,000 µjoule/cm² and independent of exposure rate from 0.1 µ watt/cm² to above 50 µwatt/cm². Optical …

Neutron And Proton Measurements Of Oso-6 Near The South Atlantic Radiation Anomaly., Philip Jay Cooper

Physics & Astronomy ETDs

The University of New Mexico High-Energy Neutron Experiment flown aboard NASA Satellite OS0-6 in 1969 was designed and built to study neutrons at an altitude of 􀀄500 km, above the earth's dense atmosphere. The detector was a proton recoil telescope with directional discrimination and was sensitive to protons as well as neutrons. Neutron data from August, 1969 to January, 1971 was analyzed in the energy range 40-120 Mev. Proton data in the energy range 60-170 Mev obtained during October and November of 1969 was also analyzed. Analysis was limited to the region of space known as the South Atlantic Radiation …

Calculation Of Potential Functions For Pseudorotation In Five Membered Rings Using Energy Gradients In Extended HüCkel Theory, Thomas Robert Ferguson

Physics & Astronomy ETDs

The gradient of the energy in extended Hückel theory (EHT) was used in a variable metric algorithm to predict the energy along the pseudorotational path for several five membered ring molecules. The molecules studied were cyclopentane, tetrahydrofuran (THF), cyclopentanol, 4-tetrahydrofuranol, and cis- and trans-3,4-tetrahydrofurandiols. Comparisons of predictions for these molecules to experimental results were made to determine the capabilities of EHT prior to an intended study of sugar rings. A background chapter discusses the recent literature on nucleic acid constituents with emphasis on the geometries of five membered sugar rings. In crystals, these geometries are found to lie mostly in …

A Method For Measuring The Electrical Conductivity Of A Shocked Liquid, Richard James Hassman

Physics & Astronomy ETDs

Development of a simple technique for the measurement of the gross electrical conductivity of a shock compressed liquid is attempted. A cell containing the sample is constructed from glass cylinders and aluminum foil. The foil is sandwiched between two cylinders of the same diameter to form a two compartment cylinder. The cylinder is mounted on a metal target plate. With both chambers of the system full of liquid, only insignificant reflections can arise from the sample-foil interface. A voltage is placed across the cell between the foil and the target plate, and the change in voltage as the shock front …

Hand Held Probe For Use In Electrical Sensing Of Plane Coordinates, George S. Hurst

Physics and Astronomy Faculty Patents

A probe with a puncturing, electrically conducting needle is constructed to enable the user, whether right or left handed, to position the needle rapidly and accurately at a selected coordinate of a sensor package.

Statistical Time-Dependent Model For The Interstellar Gas, H. Gerola, Menas Kafatos, R. Mccray

Mathematics, Physics, and Computer Science Faculty Articles and Research

We present models for temperature and ionization structure of low, uniform-density (n ~ 0.3 cm^-3) interstellar gas in a galactic disk which is exposed to soft X-rays from supernova outbursts occurring randomly in space and time. The structure was calculated by computing the time record of temperature and ionization at a given point by Monte Carlo simulation. The calculation yields probability distribution functions for ionized fraction x, temperature T, and their various observable moments. These time-dependent models predict a bimodal temperature distribution of the gas with structure in x, T that agrees with various observations. Cold regions in the low-density …

A Photographic Study Of The Infrared Oh Airglow, G. C. Loos

Physics & Astronomy ETDs

OH airglow is due to the rotational-vibrational transitions of the hydroxyl radical. Previous efforts to find the airglow's emission height in the atmosphere are discussed. Photography of the infrared airglow with a fast 35mm camera and Eastman Kodak high speed infrared film is described and a method for triangulating emission heights by two station photography is explained. The techniques for reduction of film data to height measurements and velocity measurements are presented. Observations are reported concerning the frequency of occurrence of bright spots and other features on the OH background and the intensity of the airglow as a function of …

Determination Of (N, 2n) Reaction Isomeric Cross Section For 87rb, 112cd, 138bz, And 186w Using 14 Mev Neutrons, Hsiao-Chueh Kao

Masters Theses & Specialist Projects

The purpose of this investigation was to measure the cross section for each of the reactions 87_{Rb(n, 2n)} 86m_Rb, 112_{Cd(n, 2n)}111m_Cd, 138_{Ba(n, 2n)} 137m_Ba and 186_{W(n, 2n)} 185m_W at 14.7 ± 0.03 MeV incident neutron energy. The incident neutron flux was determined during each irradiation from the activity produced in copper or aluminum disks between which the isotopically enriched sample was sandwiched. The 63_{Cu(n, 2n)}62_Cu and 27_{Al(n, p)}27_Mg reaction cross sections were assumed to be 593 ± 45 mb and 73 ± 5 …