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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 …

Heavy Particles In Therapy: An Application Of Track Theory, Robert Katz, S. C. Sharma

Robert Katz Publications

The survival, OER, and RBE for HeLa, leukemia, and kidney cells after irradiation with 14 MeV neutrons, pion beams, and heavy ion beams dispersed by ridge filters are calculated. Simple beam models and the delta-ray theory of cellular survival are used in the calculations, which refer to a mixed radiation environment and the potential application of these irradiation systems in radiotherapy.

Résumé
Particules lourdes en thérapie; une application de la théorie de trace
On a calculé la survie, l’OER et le RBE (efficacité biologique relative) pour les cellules de HeLa, de leucémie et rénales, après l’irradiation aux neutrons de 14 …

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 …

Synthetic Analogs Of The Active Sites Of Iron-Sulfur Proteins. Viii. Some Electronic Properties Of [Fe4S4(Sr)4]3; Analogs Of Reduced Bacterial Ferredoxins, R. B. Frankel, T. Herskovitz, B. A. Averill, R. H. Holm, P. J. Krusic, W. D. Phillips

Physics

One-electron reduction of the synthetic tetramers [Fe₄S₄(SR)₄]^2- (R = CH₂Ph, Ph), by chemical and electrochemical methods affords the corresponding trianions. The collective results from optical, electron paramagnetic resonance, and Mössbauer spectroscopy, when compared to available data for reduced 4-Fe and 8-Fe ferredoxin proteins and super-reduced Chromatium high-potential protein, reveal that [Fe₄S₄(SR)₄]^3- are electronic analogs of the [Fe₄S₄(S-Cys)₄] active sites of these proteins.

Photoelectron Angular Distributions, Cross Sections, And Branching Ratios For Atomic Oxygen, Anthony F. Starace, Steven T. Manson, David J. Kennedy

Anthony F. Starace Publications

Theoretical calculations of the angular distribution of photoelectrons ejected from the 2p subshell of atomic oxygen for photoelectron kinetic energies 0≤ε≤30 Ry are presented using both Hartree-Fock (HF) and Herman-Skillman (HS) wave functions. Owing to the weakness of anisotropic electron-ion interactions, as evidenced by small differences between HF photoelectron phase shifts for alternative outgoing channels, the simple HS calculation of the angular-distribution asymmetry parameter is found to agree to within ≲ 0.1 with the HF calculations. Photoionization cross sections and photoelectron branching ratios have also beem computed in both the HF and HS approximation for the 2p subshell …

Eikonal Distorted-Wave Calculation For The Excitation Of H By He, Jerry Peacher, Richard H. Shields

Physics Faculty Research & Creative Works

The eikonal distorted-wave Born approximation developed recently by Chen, Joachain, and Watson is applied to hydrogen excitation by helium impact in the intermediate-energy range. The differential and total cross sections for the excitation of the hydrogen atom to the 2s, 2p_±, or 2p₀ state by helium impact are presented. These results are compared to experiment and previous calculations. The differential cross section for the excitation of hydrogen to the 2s state compares well with the experimental data of Thomas and Sauers in shape and slope, but has a discrepancy in magnitude.

Heat Transfer Across Carbon - Liquid Helium I Interface, Constantine Antonopoulos

Dissertations and Theses

Carbon samples were electrically heated while immersed in liquid helium I. Their temperature rise was observed on an oscilloscope as a function of the time after the onset of the electric current. There was no indication of the temperature overshoot previously reported for the case of bismuth in liquid helium.

Reasons are presented for the difference in behavior of carbon and bismuth.

Vibration Damping Characteristics Of Typical Harpsichord Strings, Jack Lee Simmons

Dissertations and Theses

Present-day builders of harpsichords disagree as to the use of iron or carbon-steel wire in their attempt to duplicate the tonal qualities of the early 16th century instruments. The variations in tone produced by vibrating iron and steel wires may be due, at least in part, to differences in their decay characteristics. A wire was set into vibration by placing a section in a magnetic field and passing a variable-frequency alternating current through it. A condition of resonance was established by appropriately selecting frequencies, lengths, and tensions that would simultaneously satisfy the relationship: fr = n/2L(T/p)1/2. Then measurements of decay …

Photoelectron Angular Distributions As A Probe Of Anisotropic Electron-Ion Interactions, Dan Dill, Steven T. Manson, Anthony F. Starace

Anthony F. Starace Publications

Expressions are given for atomic photoelectron angular distributions in LS coupling in which the role of anisotropic final state electron-ion interactions emerges explicitly. Calculations of photoelectron angular distributions for atomic sulfur are presented in which these anisotropic interactions produce clear deviations from the predictions of the Cooper-Zare model. Such effects are expected to be a general feature of photoelectron angular distributions for most open-shell atoms.

Electrical Characteristics Of Al‐Implanted Znse, B. K. Shin, Y. S. Park, David C. Look

Physics Faculty Publications

Aluminum was implanted in ZnSe at 90 keV to a dose of 10¹⁵ ions/cm² at room temperature. Hall‐effect and sheet‐resistivity measurements were made on the samples for various annealing conditions. The implanted layer is found to be degenerate n‐type having a sheet resistivity of ∼10³ Ω/□, after annealing at 900°C for 4 h.

An Experimental And Theoretical Study Of The Flow Phenomena Within A Vortex Sink Rate Sensor, Dashrath Khodidas Patel

Mechanical & Aerospace Engineering Theses & Dissertations

The objective of this investigation was to obtain a detailed description of the flow field within a vortex sink rate sensor and to observe the influence of viscous effects on its performance.

The sensor basically consists of a vortex chamber and a sink tube. The vortex chamber consists of two circular coaxial disks held apart, at their periphery, by a porous coupling. One circular disk has an opening to permit the mounting of the sink tube, in such a manner that the vortex chamber as well as the sink tube have a common axis of rotation.

Air was supplied radially …

A Theoretical Proton-Proton Pair Production Cross-Section Calculation, Jay W. Phippen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The calculation of both electron-pair and muon-pair production cross-sections was made using Feynman's quantum electrodynamics. Pseudo-scaler coupling was used between the nucleons and vector coupling was used between the photon and the Fermions. The protons were considered as Dirac particles and radiative corrections were omitted.

Eight fourth-order Feynman-Dyson diagrams were used. The subsequent sixty-four TRACES were reduced to seven basic topologically different TRACES. From the seven basic TRACES, it was possible to generate the sixty-four TRACES by the proper permutations of the variables.

With the mathematics and the corresponding computer programs written down, data (energies and momenta which represent the …

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 …

Angular Distribution Of Photoelectrons From Atomic Oxygen, Nitrogen, And Carbon, Steven T. Manson, David J. Kennedy, Anthony F. Starace, Dan Dill

Anthony F. Starace Publications

The angular distributions of photoelectrons from atomic oxygen, nitrogen and carbon are calculated. Both Hartree-Fock and Hartree-Slater (Herman-Skillman) wave functions are used for oxygen, and the agreement is excellent; thus only Hartree-Slater functions are used for carbon and nitrogen. The pitch angle distribution of photoelectrons is discussed and it is shown that previous approximations of energy independent isotropic or sin² θ distributions are at odds with our results, which vary with energy. This variation with energy is discussed as is the reliability of these calculations.

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.

The Use Of Transactional Analysis With Inquiry Methods In Physics Teaching, Robert Fuller, Ward L. Sims

Robert G. Fuller Publications

We now offer a course that combines an inquiry approach to physics with elementary school science teaching methods and transactional analysis. Our course carries three semester credits in elementary science methods and three semester credits in physics, a total of nine contact hours per week. In previous interim courses the very positive response we have had from our students, i.e., the excitement in discovering some real physics for themselves, and their decision to use the tools of transactional analysis to say "OK" to themselves and physics, leads us to believe that our course can serve as a useful model for …

Theoretical And Experimental Studies Of The Second-Order Raman Spectra Of Cscl, Csbr, And Csi, B.S. Agrawal, Roger D. Kirby, John R. Hardy

Roger Kirby Publications

Measurements of the second-order Raman spectra of CsCl, CsBr, and CsI have been made at both 300 and 80 °K. From these the three independent spectral components, A 1g, E g, and T 2g, have been determined for all three crystals at both temperatures. A theoretical interpretation of these data has been carried out using the phenomenological Born-Bradburn model to describe the Raman polarizability tensor and the deformation-dipole model to provide the lattice-dynamical eigendata. We have found it possible to obtain an excellent description of the observed spectra retaining 16 of the first- and second-neighbor polarizability derivatives in the Born-Bradburn …

Abstract: Phase Transitions In Fecl2·2h2O In External Magnetic Fields: Mössbauer Spectroscopy, L. D. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo

Physics

Monoclinic FeCl₂·2H₂O orders antiferromagnetically at T_N = 23 K, and the magnetic structure consists of two sublattices of -FeCl₂-chains lying along the c-axis. The coupling along the chains is ferromagnetic with weak antiferromagnetic coupling between chains. Application of an external magnetic field along the easy axis (a) induces phase transitions at H₁ = 39 kOe and at H₂ = 46 kOe.

We report the observation of the three phases using the Mössbauer effect in a single crystal of FeCl₂·2H₂O cut parallel to the c-axis and placed at …

An Ok Science Teacher, Robert Fuller

Robert G. Fuller Publications

Many elementary school teachers feel insecure and unsure in their teaching of science, i.e., they have NOT OK feelings about themselves and science. These feelings are based on the teachers' previous science experiences and on their interactions with other persons in science courses. The improvement of elementary school science programs depends upon the teacher's ability to deal effectively with his feelings about science. A complete science education program for an elementary teacher includes three components: (1) science content, (2) science methods that take into consideration the intellectual development of children, and (3) a practical psychology for developing positive human attitudes …

Phonon-Induced Second-Order Raman Scattering In Lif, T.P. Sharma, Roger D. Kirby, Sitaram Jaswal

Roger Kirby Publications

We have studied experimentally and theoretically the second-order Raman spectra of LiF. Theoretical calculations based on Born and Bradburn's approach explain the observed spectra fairly well when all the eight-nearest-neighbor, only two of the fifteen-next-nearest-neighbor negative-negative, and none of the fifteen next-nearest-neighbor positive-positive polarizability coefficients are used as adjustable parameters.

Evidence For The Ωππ Decay Modes Of The A₂ And Ω(1675), J. Diaz, F. A. Dibianca, William J. Fickinger, A. Malko, D. K. Robinson, C. R. Sullivan

Faculty Scholarship

We present evidence for the decay A20→ωπ+π0 with a branching ratio Γ(A2→ωππ)/Γ(A2→ρπ)=0.28±0.09 and for the decay ω(1675)→ωπ+π- with a branching ratio Γ(ω(1975)→ωπ+π-)/Γ(ω(1675)→ρπ)=0.47±0.18. Evidence is given for an intermediate B(1235)π state in the ω(1675) decay.

Pb And Bi L-Subshell Ionization Cross-Section Ratios Versus Proton Bombarding Energy From 0.5 To 4 Mev, Don H. Madison, A. B. Baskin, C. E. Busch, Stephen M. Shafroth

Physics Faculty Research & Creative Works

Experimental ratios of L-subshell cross sections are given for ionization of lead and bismuth by 0.5-4-MeV-proton bombardment. The ratio of the L_II to L_I cross sections exhibits a maximum near 1.75 MeV. Individual subshell cross sections are obtained from the experimental ratios and previous total-cross-section data. These subshell ratios and cross sections are compared with the theoretical predictions of the plane-wave Born approximation using nonrelativistic hydrogenic wave functions, of the binary-encounter approximation scaled from Mg K-shell cross sections, and of the binary-encounter approximation scaled from cross sections obtained using L-shell velocity distributions. It was found that both approximations …

Diffusion-Controlled Intrachain Reactions Of Polymers. I Theory, Gerald Wilemski, Marshall Fixman

Physics Faculty Research & Creative Works

A theory of diffusion-controlled intramolecularly catalyzed reactions of polymer chains in dilute solution is formulated. A closure approximation yields a soluble integral equation for (essentially) the transient rate of the reaction. The time dependent solution consists of a sum of simple exponential terms whose coefficients and decay constants can be readily calculated. The theory is also applied to luminescence quenching and ring-chain interconversion.

Diffusion-Controlled Intrachain Reactions Of Polymers. Ii Results For A Pair Of Terminal Reactive Groups, Gerald Wilemski, Marshall Fixman

Physics Faculty Research & Creative Works

The formulas and results of the preceding paper are used to calculate the rate of reaction between reactive groups attached to the ends of a polymer chain. Extensive numerical calculations have been made for both transient rate processes and steady state luminescence quenching. The results are restricted to chains in dilute solution, in either the free draining or nondraining limits and with no excluded volume forces present. A discussion of the qualitative effects of excluded volume forces on the results is included. The results suggest that experimental studies of these processes may be feasible.

Eikonal Approximation Applied To Atom-Atom Excitation At Intermediate Energies: Excitation Of H By H, Richard H. Shields, Jerry Peacher

Physics Faculty Research & Creative Works

The eikonal distorted-wave Born approximation (DWBA) developed recently by Chen, Joachain, and Watson is applied to atom-atom excitation in the intermediate energy range. In this paper the excitation of a hydrogen atom to the 2s, 2p_±, or 2p₀ state by hydrogen impact is considered. Differential cross sections are presented. Total cross sections are presented and compared to previous calculations. It is shown that the eikonal DWBA results for the total cross section approach the two-state distortion-approximation results in the limit of high energy and very-small-angle scattering.

Mössbauer Spectroscopy Of Magnetic Phases In Fecl2 · 2h2O, L. Kandel, M. A. Weber, Richard B. Frankel, C. R. Abeledo

Physics

Mössbauer spectroscopy of the three magnetic phases of single crystal FeCl₂ · 2H₂ in external magnetic fields at 4.2 K is reported.

Effect Of Virtual 4d-Shell Excitations On Rare Earth Spectra, Anthony F. Starace

Anthony F. Starace Publications

Ab initio energies for electric dipole transitions 4d¹⁰ (¹S₀) → 4d⁹4f J = 1 in triply-ionized lanthanum have been calculated by constructing an effective interaction, acting within the configuration 4d⁹4f, that incorporates effects of virtual 4d-shell excitations to all orders of perturbation. Virtual 4d-shell excitations, included within the random phase approximation, and virtual excitations to singly-excited configurations 4d⁹εf are found to reduce the ordinary electrostatic interaction by 38% for the ¹P₁ term of 4d⁹4f, by 6% for the ³D₁ term, and by 3% …

Incoherent-Scatter Radar Observations Of Westward Electric Fields, 2, C L. Rino, Vincent B. Wickwar, P M. Banks, E Rieger, S Akasofu

All Physics Faculty Publications

In this paper we describe the results of a series of geomagnetic meridian plane radar incoherent scatter plasma transport measurements. From such data the eastward (zonal) component of the electric field can be deduced. The results show that the electric field has an eastward component whenever the discrete auroras are northward of the region of the measurement. The zonal field component turns westward as the discrete auroras move equatorward of the region of the measurement. Thus there is an eastward electric field boundary near the equatorward limit of the discrete aurora, which is the poleward boundary of the diffuse aurora …

Physical Meaning Of The Field H, H. E. Mccloud

Journal of the Arkansas Academy of Science

Through the introduction of the concept of magnetic charge the physical meaning of the magnetic field H is established within the rationalized MKS system of units