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Response Of Lithographic Mask Structures To Repetitively Pulsed X-Rays: Dynamic Response, Clive L. Dym, A. Ballantyne Jan 1985

Response Of Lithographic Mask Structures To Repetitively Pulsed X-Rays: Dynamic Response, Clive L. Dym, A. Ballantyne

All HMC Faculty Publications and Research

This paper addresses the issue of the dynamic response of thin lithographic mask structures to thermally induced stress fields. In particular, the impact of repetitively pulsed x‐ray sources are examined: the short duration (1–100 nsec) pulses induce large step changes in mask temperatures, which can, in turn, induce a dynamic response. The impact of conductive cooling of the mask is to reduce the repetitively pulsed problem to a series of isolated nearly identical thermal impulses of duration approximately equal to the cooling time. The importance of self‐weight and prestress is examined, and an analysis of the nonlinear dynamic response to …

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The Production Of Highly Unidirectional Lower-Hybrid Waves, R. Mcwilliams, M. Okubo, R. C. Platt, D. P. Sheehan Jan 1985

The Production Of Highly Unidirectional Lower-Hybrid Waves, R. Mcwilliams, M. Okubo, R. C. Platt, D. P. Sheehan

Physics and Biophysics: Faculty Scholarship

The development of a highly unidirectional lower-hybrid wave source would improve the electron current drive efficiency in tokamaks. Lower-hybrid waves launched from a phased wave array are shown to be reflected from a grid placed in a cold, low-density plasma. The antenna-grid combination results in highly unidirectional lower-hybrid waves.

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Advances In Verification Technology, David W. Hafemeister Jan 1985

Advances In Verification Technology, David W. Hafemeister

Physics

The alleged limits of verification techniques have been used to justify lack of action at the negotiating table, but advances in computer science and optics should help dispel doubts about the verifiability of treaties

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The Vibrational Distribution Of N2+ In The Terrestrial Ionosphere, Jane L. Fox, Alexander Dalgarno Jan 1985

The Vibrational Distribution Of N2+ In The Terrestrial Ionosphere, Jane L. Fox, Alexander Dalgarno

Physics Faculty Publications

The densities and vibrational distributions of N2+ in the X²Σg+, A²Πu, and B²Σu+ states in the daytime terrestrial ionosphere are computed for both low and high solar activity. Altitude profiles of the relative populations of the vibrational levels of N2+X²Σg+ are presented. The fraction of vibrationally excited N2+ varies from 5% at 100 km to 50% at 450 km. Several models are examined in which loss of N2+(v) is enhanced for v > 0 and in …

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Analysis Of Solar Collector Surface To Air Flow Thermal Transfer Using Solid State Sensors And Microcomputer Interfacing, Rudolph J. Eichenberger Jan 1985

Analysis Of Solar Collector Surface To Air Flow Thermal Transfer Using Solid State Sensors And Microcomputer Interfacing, Rudolph J. Eichenberger

Journal of the Arkansas Academy of Science

No abstract provided.

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Low-Dimensional Chaotic Attractors For An Unstable, Inhomogeneously Broadened, Single-Mode Laser, Alfonso M. Albano, J. Abounadi, T. H. Chyba, C. E. Searle, S. Yong, R. S. Gioggia, N. B. Abraham Jan 1985

Low-Dimensional Chaotic Attractors For An Unstable, Inhomogeneously Broadened, Single-Mode Laser, Alfonso M. Albano, J. Abounadi, T. H. Chyba, C. E. Searle, S. Yong, R. S. Gioggia, N. B. Abraham

Physics Faculty Research and Scholarship

Quantitative characterization of the intensity pulsations from an inhomogeneously broadened laser confirm that observed irregular pulsing has its origins in deterministic chaos corresponding to motion on a strange attractor of low fractal dimensionality. The pointwise information dimension and the Grassberger-Procaccia K2 (estimators from below of the fractal dimensionality of the attractor and the Kolmogorov entropy, respectively) have been determined for digitized time series from parameter regions identified qualitatively by power spectra as representing periodic, period-doubled, quasi-periodic, and chaotic behavior. Some amount of chaos seems present for almost all operating conditions.

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Evidence For Uncorrelated Electron Capture And K-Shell Excitation In S13++He Collisions, J. A. Tanis, E. M. Bernstein, M. W. Clark, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones, M. Meron Jan 1985

Evidence For Uncorrelated Electron Capture And K-Shell Excitation In S13++He Collisions, J. A. Tanis, E. M. Bernstein, M. W. Clark, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones, M. Meron

Physics Faculty Research & Creative Works

Evidence is presented for a two-step process in ion-atom collisions in which two independent interactions occur in a single encounter. Measurements for 15200-MeVS13++He collisions indicate that uncorrelated projectile K-shell excitation and capture of a target electron occur in a single collision with one target atom. The results are in reasonable qualitative agreement with theoretical predictions of this two-step process. © 1985 The American Physical Society.

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Effects Of Iron Implantation On The Aqueous Corrosion Of Magnesium, S. Akavipat, Edward Boyd Hale, C. E. Habermann, P. L. Hagans Jan 1985

Effects Of Iron Implantation On The Aqueous Corrosion Of Magnesium, S. Akavipat, Edward Boyd Hale, C. E. Habermann, P. L. Hagans

Physics Faculty Research & Creative Works

The influence of the implantation of iron ions on the corrosion of magnesium and an AlZn-rich magnesium alloy (AZ91C) has been studied. Anodic polarization measurements in a dilute chloride-containing alkaline solution were used to evaluate corrosion resistance. A range of ion energies (50-180 keV) and doses (1016-2 x 1017 Fe+ ions cm-2) have been evaluated. Both the iron-implanted pure magnesium and the alloy AZ91C gave improved polarization measurements. A systematic positive shift of the open-circuit potential with increasing iron dose was found. In AZ91C at a dose of 1017 Fe+ ions cm-2, there was a + 0.6 V more noble …

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Corrosion In Magnesium And A Magnesium Alloy (Az91c) As Modified By Ion Implantation, Sanay Akavipat Jan 1985

Corrosion In Magnesium And A Magnesium Alloy (Az91c) As Modified By Ion Implantation, Sanay Akavipat

Doctoral Dissertations

"Magnesium and a magnesium alloy (AZ9 1C) have been ion implanted over a range of ion s energies (50 to 150 keV) and doses (1 x 1016 to 2 x 1017 ions/cm2) to modify the corrosion properties of the metals. The corrosion tests were done by anodic polarization in chloride -free and chloride containing aqueous solutions of a borated-boric acid with a pH of 9.3. Anodic polarization measurements showed that some implantations could greatly reduce the corrosion current densities at all impressed voltages and also increased slightly the pitting potential, which indicated the onset of the …

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Cosmic Rays And The Emission-Line Regions Of Active Galactic Nuclei, Gary J. Ferland, R. F. Mushotzky Nov 1984

Cosmic Rays And The Emission-Line Regions Of Active Galactic Nuclei, Gary J. Ferland, R. F. Mushotzky

Physics and Astronomy Faculty Publications

We discuss the effects that the synchrotron emitting relativistic electrons, which are known to exist throughout many distance scales in active nuclei, could have on the emission-line regions that characterize these objects. Detailed models of both the inner, dense, broad-line region and the outer, lower density, narrow-line region are presented, together with the first models of the optically emitting gas often found within extended radio lobes. We show that, in all cases, if the relativistic gas that produces the synchrotron radio emission is mixed with the gas in the emission-line region, then significant changes in the emission-line spectrum will result. …

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Multiple Determination Of The Optical Constants Of Thin-Film Coating Materials, D. P. Arndt, R. M.A. Azzam, J. M. Bennett, J. P. Borgogno, C. K. Carniglia, W. E. Case, J. A. Dobrowolski, U. J. Gibson, T. Tuttle Hart, F. C. Ho, V. A. Hodgkin, W. P. Klapp, H. A. Macleod, E. Pelletier, M. K. Purvis, D. M. Quinn, D. H. Strome, R. Swenson, P. A. Temple, T. F. Thonn Oct 1984

Multiple Determination Of The Optical Constants Of Thin-Film Coating Materials, D. P. Arndt, R. M.A. Azzam, J. M. Bennett, J. P. Borgogno, C. K. Carniglia, W. E. Case, J. A. Dobrowolski, U. J. Gibson, T. Tuttle Hart, F. C. Ho, V. A. Hodgkin, W. P. Klapp, H. A. Macleod, E. Pelletier, M. K. Purvis, D. M. Quinn, D. H. Strome, R. Swenson, P. A. Temple, T. F. Thonn

Electrical Engineering Faculty Publications

The seven participating laboratories received films of two different thicknesses of Sc2O3 and Rh. All samples of each material were prepared in a single deposition run. Brief descriptions are given of the various methods used for determination of the optical constants of these coating materials. The measurement data are presented, and the results are compared. The mean of the variances of the Sc2O3refractive-index determinations in the 0.40–0.75-nm spectral region was 0.03. The corresponding variances for the refractive index and absorption coefficient of Rh were 0.35 and 0.26, respectively.

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Statement Of Dr. David Hafemeister Regarding The Need To Convert Domestic Research Reactors From Highly Enriched To Low-Enriched Uranium Fuels, David W. Hafemeister Oct 1984

Statement Of Dr. David Hafemeister Regarding The Need To Convert Domestic Research Reactors From Highly Enriched To Low-Enriched Uranium Fuels, David W. Hafemeister

Physics

No abstract provided.

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Three-Reflection Halfwave And Quarterwave Retarders Using Dielectric-Coated Metallic Mirrors, T. F. Thonn, R. M.A. Azzam Aug 1984

Three-Reflection Halfwave And Quarterwave Retarders Using Dielectric-Coated Metallic Mirrors, T. F. Thonn, R. M.A. Azzam

Electrical Engineering Faculty Publications

A design procedure is described to determine the thicknesses of single-layer coatings of a given dielectric on a given metallic substrate so that a specified net phase retardance (and/or a net relative amplitude attenuation) between the p and s polarizations is achieved after three reflections from a symmetrical arrangement of three mirrors that maintain collinearity of the input and output beams. Examples are presented of halfwave and quarterwave retarders (HWR and QWR) that use a ZnS-Ag film-substrate system at the CO2-laser wavelength λ = 10.6 µm. The equal net reflectances for the p and s polarizations are computed …

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26th Rocky Mountain Conference Aug 1984

26th Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 26th annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 7-8, 1984.

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Inverting The Ratio Of The Complex Parallel And Perpendicular Reflection Coefficients Of An Absorbing Substrate Using A Transparent Thin-Film Coating, R. M.A. Azzam Jul 1984

Inverting The Ratio Of The Complex Parallel And Perpendicular Reflection Coefficients Of An Absorbing Substrate Using A Transparent Thin-Film Coating, R. M.A. Azzam

Electrical Engineering Faculty Publications

An absorbing substrate can be coated with a transparent thin film of refractive index N1 (within a certain range) and thickness d such that the ratio of complex reflection coefficients for the p_and s polarizations of the film-covered substrate ρ = Rp/Rs is the inverse of that of the film-free substrate ρ¯ = R¯p/R¯s at an angle of incidence ø. A method to determine the relationship among ø, N1, and d that inverts ρ (i.e., makes ρ = 1/ρ¯) for a given substrate at a given wavelength is described and is …

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Implementation Of Uniform Perturbation Method For Potential Flow Past Axisymmetric And Two-Dimensional Bodies, Tin Chee Wong Jul 1984

Implementation Of Uniform Perturbation Method For Potential Flow Past Axisymmetric And Two-Dimensional Bodies, Tin Chee Wong

Mechanical & Aerospace Engineering Theses & Dissertations

The aerodynamic characteristics of potential flow past an axisymmetric slender body and a thin airfoil are calculated by using a uniform perturbation analysis method. The method is based on the superposition of potentials of point singularities distributed inside the body. The strength distribution satisfies a linear integral equation by enforcing the flow tangency condition on the surface of the body. The complete uniform asymptotic expansion of its solution is obtained with respect to the slenderness ratio by modifying and adapting an existing technique. Results calculated by the perturbation analysis method are compared with the existing surface-singularity-panel method and some available …

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A Simple Model For Impurity Photoabsorption In Silicon, Gust Bambakidis Jun 1984

A Simple Model For Impurity Photoabsorption In Silicon, Gust Bambakidis

Physics Faculty Publications

A simple model for absorption of infrared radiation by impurity atoms in silicon crystals has been developed and applied to electronic excitations ofthe Group V donors Bi, Sb, As, and P, and the Group III acceptors B, AI, Ga, and In. The model is based on the quantum-defect method for approximating bound donor or acceptor wave functions outside the core region of the impurity. For each donor species, the relative oscillator strengths have been calculated for the transitions from the ground state to the first four excited levels. For each acceptor species, the relative oscillator strengths were calculated for transitions …

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Division-Of-Wave-Front Polarizing Beam Splitter And Half-Shade Device Using Dielectric Thin Film On Dielectric Substrate, R. M.A. Azzam May 1984

Division-Of-Wave-Front Polarizing Beam Splitter And Half-Shade Device Using Dielectric Thin Film On Dielectric Substrate, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

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A Quantitative Study Of The Copper Content In Granite Rocks, Samir F. Al-Mandwee Apr 1984

A Quantitative Study Of The Copper Content In Granite Rocks, Samir F. Al-Mandwee

Masters Theses

A spectrographic analysis was conducted on ten granite samples of different geological origin from the Pioneer Mountains in Central Idaho. A qualitative analysis was performed first and then a quantitative analysis to determine the presence and relative amounts of copper in the various samples. This spectrographic analysis employed a direct current arc source of 340 volts and 4 amperes to excite the samples which were dissolved in acid and dried on the ends of high purity carbon electrodes. The emitted light passed through a step sector and a medium quartz spectrograph to a photographic plate. The optical density of the …

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The Development Of A Microprocessor Controlled Linearly Actuated Valve Assembly, Raymond H. Wall Apr 1984

The Development Of A Microprocessor Controlled Linearly Actuated Valve Assembly, Raymond H. Wall

Mechanical & Aerospace Engineering Theses & Dissertations

The development of a proportional fluid control valve/assembly is presented. This electro-mechanical system is needed for space applications to replace the current proportional flow controllers that use bulky hydraulic or pneumatic actuation systems. The flow is controlled by a microprocessor system that monitors the control parameters of upstream pressure and requested volumetric flow rate. The microprocessor achieves the ·proper valve stem displacement by means of a digital linear actuator. A linear displacement sensor is used to measure the valve stem position. 'Ibis displacement is monitored by the microprocessor system as a feedback signal to close the control loop. With an …

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An Investigation Of Refractive Index Of Solutions Of Ammonia And Water At Various Concentrations And Temperatures, Effendy Arif Apr 1984

An Investigation Of Refractive Index Of Solutions Of Ammonia And Water At Various Concentrations And Temperatures, Effendy Arif

Mechanical & Aerospace Engineering Theses & Dissertations

Refractive index of ammonia-water solutions is investigated experimentally (for (lamda) = 632.8 nm) and semi-empirically (for (lamda) = 589.3 and 632.8 nm) in ammonia-weight concentration of up to 30%, over a temperature range of 20 to 60(DEGREES)C. The experiment employs a specially designed and built refractometer that measures the displacement of a laser beam due to refraction in the test solution. The refractive index is then deduced from the beam displacement. Based on the experimental data, the refractive index is correlated empirically with the concentration and temperature. A semi-empirical investigation is developed based on the Lorentz-Lorenz equation and the additive …

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Homogeneous Nucleation Rate For Water, Donald E. Hagen, James L. Kassner Apr 1984

Homogeneous Nucleation Rate For Water, Donald E. Hagen, James L. Kassner

Physics Faculty Research & Creative Works

Homogeneous nucleation rate data for water extending over an exceptionally large domain of rate (J), supersaturation ratio (S), and temperature (T) was recently published. Because it spans a large J-S-T surface, this data constitutes a good test of nucleation theory. Here classical nucleation theory is used to analyze this data. By adjusting only the sticking coefficient, we are able to obtain a good fit between theory and experiment. It was necessary to include an increase in the water molecular density associated with the finite water compressibility.

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A Plasma Focus Interrupting Switch, Gregory Francis Knapp Apr 1984

A Plasma Focus Interrupting Switch, Gregory Francis Knapp

Electrical & Computer Engineering Theses & Dissertations

The feasibility of using a dense plasma focus (DPF) as a current interrupting device has been investigated. Specifically, a 34-kJ, Mather-type DPF was modified to accept a third electrode so that a discharge could be created between this electrode and the center electrode of the DPF by a 10-kJ inductive energy storage circuit. It was anticipated that the accelerating mechanisms of the DPF pinch, which are known to cause a rapid reduction in the DPF current, would interrupt the 1-kA to 10-kA secondary discharge current thus forcing the secondary current through an external load and hence result in power amplification. …

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Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble Jan 1984

Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble

All Physics Faculty Publications

Observations of nighttime thermospheric neutral winds made at Sondre Stromfjord, Greenland, with optical and radar instrumentation, showed an occasional abatement in the equatorward meridional wind at a magnetic local time corresponding to the nighttime division between the evening and morning convection cells. This abatement appeared primarily in the poleward observations. In contrast, however, the characteristic midnight “surge” was usually seen in the equatorward set of observations. The apparent acceleration of about 250 m/s or greater within 4.6° latitude we attribute, in part, to a merging of neutral jet streams generated by polar cap ion drag adjacent to the auroral zone …

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Pitch Angle Properties Of Magnetospheric Thermal Protons And Satellite Sheath Interference In Their Observation, Jan Josef Sojka, G. L. Wrenn, J.F. E. Johnson Jan 1984

Pitch Angle Properties Of Magnetospheric Thermal Protons And Satellite Sheath Interference In Their Observation, Jan Josef Sojka, G. L. Wrenn, J.F. E. Johnson

All Physics Faculty Publications

Cold proton observations from the geosynchronous GEOS 2 satellite are presented to show the pitch angle distribution of the refilling cold ion population found beyond the plasmapause. This refilling cold ion population flows into the depleted equatorial regions of the flux tubes from the topside ionosphere. This refilling is observed both day and night. The ions have energies between 0.5 and 3 eV. These energy characteristics are consistent with other recent observations. Although the observed angular distribution of these ions is highly complex, when allowance is made for the satellite sheath several conclusions can be made concerning the ion pitch …

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Systematic Estimate Of Binding Energies Of Weakly Bound Diatomic Molecules, Linda L. Vahala, Mark D. Havey Jan 1984

Systematic Estimate Of Binding Energies Of Weakly Bound Diatomic Molecules, Linda L. Vahala, Mark D. Havey

Electrical & Computer Engineering Faculty Publications

There is often insufficient spectroscopic data for a full RKR inversion to yield a potential for weakly bound diatomic molecules. In these cases, parametrized functions such as the Morse or Thakkar potentials may be used to obtain estimates of the binding energy. The Thakkar potential is more flexible, and has been used successfully on some weakly bound systems. In the more usual case, the Thakkar parameter p, which determines long range behavior R-p, is chosen by p=-a1-1, where a1 is the first Dunham coefficient; p is usually noninteger. The authors present …

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The Feasibility Of The X-Ray Laser Pumped With A Nuclear Explosion, David W. Hafemeister Jan 1984

The Feasibility Of The X-Ray Laser Pumped With A Nuclear Explosion, David W. Hafemeister

Physics

Recent reports have indicated that an x-ray laser pumped with a nuclear explosion at a wavelength of 1.4nm (0.9 keV) has made some initial progress. It has been proposed to extend the development of this device to establish it as part of a layered ballistic missile defensive system to protect the United States against a nuclear attack. This paper will discuss the following aspects on the feasibility of this system: (1) Conditions affecting the efficiency of the X-ray laser; (2) Angular resolution and size of.the laser rods; (3) Energy on targets; (4) Basing Modes; (5) Countermeasures; and (6) Legal constraints.

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Non-Linear Oscillation, Automodulation And Anelasticity, Tetsuro Suzuki, Manfred Wuttig Jan 1984

Non-Linear Oscillation, Automodulation And Anelasticity, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

The auto modulation observed in the course of internal friction is discussed as a special example of the universal nature of non-linear oscillations. Universal features of non-linear oscillations are the requirement of energy supply or negative damping and the period doubling route to chaos. The negative damping responsible for the auto modulation is described in terms of the soliton model for twinning deformation. © 1984 The Japan Society of Applied Physics.

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The Homogeneous Nucleation Of Nonane, G. W. Adams, John L. Schmitt, R. A. Zalabsky Jan 1984

The Homogeneous Nucleation Of Nonane, G. W. Adams, John L. Schmitt, R. A. Zalabsky

Physics Faculty Research & Creative Works

The homogeneous nucleation rate of n-nonane has been measured as a function of temperature and supersaturation ratio in a precision fast-expansion chamber. The measured nucleation rate ranges from 102 to 105 drops/cm3 over the temperature range 215-270 K. The results have been compared to the classical theory and to the classical theory with the RKC replacement factor. The RKC theory functional form is the basis for an empirical rate equation to fit the data. A full listing of the thermodynamic constants used for the reduction of the data is given. © 1984 American Institute of Physics.

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Radiation Damage To Gaas Solar Cells Including Isotropic Effects, Larry Victor Stock Jan 1984

Radiation Damage To Gaas Solar Cells Including Isotropic Effects, Larry Victor Stock

Physics Theses & Dissertations

A model is developed for the short circuit current of a GaAs solar cell due to radiation (proton or electron) induced defects in the crystal structure. This model is verified by a comparison with proton and electron irradiation results. For electron radiation and energetic protons (energy> 10 MeV), it is found that the damage in the crystal is independent of the angle of incidence. On the other hand, for lower energy proton radiation, the damage as a function of cell thickness is highly dependent on incident angle and energy. The cell's response to low energy protons is strongly dependent on …

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