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Faculty Publications

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Articles 3661 - 3690 of 3783

Full-Text Articles in Physical Sciences and Mathematics

Origin Of The Peaked Structure In The Conductance Of One-Dimensional Silicon Accumulation Layers, Richard A. Webb, A. Hartstein, J. J. Wainer, A. B. Fowler Apr 1985

Origin Of The Peaked Structure In The Conductance Of One-Dimensional Silicon Accumulation Layers, Richard A. Webb, A. Hartstein, J. J. Wainer, A. B. Fowler

Faculty Publications

We have made extensive studies of the temperature, gate voltage, and electric field dependences of the conductance peaks in small silicon inversion layers in order to distinguish between resonant-tunneling models and a hopping model. We find that many of the peaks are consistent only with a hopping model, whereas some could be consistent with an early resonant-tunneling model. None of our structure is consistent with resonant tunneling if the recent formulation of Stone and Lee is correct.

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Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer Mar 1985

Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer

Faculty Publications

During the past two decades in Hawaii, more than 500 injection wells for the disposal of domestic sewage wastewater have been constructed and operated. Thus far, contamination of potable groundwater supplies has not been a problem. Many of the injection wells, however, have not performed as designed, and aquifer clogging and reduced injection capacity have produced numerous well failures resulting in public health, legal, and financial problems. Factors most commonly responsible for the well problems have been unfavorable hydrogeology, underdesign of injection well capacity, poor effluent quality, and lack of injection well maintenance. Detailed study of clogging mechanisms in the …

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G-Factor Measurements Of 41+ States In The N=82 Isotones 136xe And 138ba, Z. Berant, A. Wolf, John C. Hill, F. K. Wohn, R. L. Gill, H. Mach, M. Rafailovich, H. Kruse, B. H. Wildenthal, Graham F. Peaslee, A. Aprahamian, J. Goulden, C. Chung Feb 1985

G-Factor Measurements Of 41+ States In The N=82 Isotones 136xe And 138ba, Z. Berant, A. Wolf, John C. Hill, F. K. Wohn, R. L. Gill, H. Mach, M. Rafailovich, H. Kruse, B. H. Wildenthal, Graham F. Peaslee, A. Aprahamian, J. Goulden, C. Chung

Faculty Publications

The g factors for the 4+1 states in Xe136 and Ba138 were measured using the method of time-integral perturbed angular correlation. The levels of interest were populated by the decay of mass-separated I136 and Cs138. g factors of 0.80±0.15 and 0.80±0.14 were measured for the 4+1 states in Xe136 and Ba138, respectively. The above results, along with those for the g factors in the 4+1 state in Ce140 and the 6+1 states in Te134 and Ba138, are well described by a shell-model calculation in which the effective elemental proton g factors are g’l=1.12 and g’s=4.12.

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Example Of A Group Action Determined Phase Transition, Jeffrey W. Felix, Dorian M. Hatch Feb 1985

Example Of A Group Action Determined Phase Transition, Jeffrey W. Felix, Dorian M. Hatch

Faculty Publications

The principles of the group action approach to structural phase transitions are outlined. It is assumed that all properties of the transition are determined by the action of a single physically irreducible represention of the space group of the more symmetric phase. We determine the isotropy groups using the image space of the representation. The free energy minima are determined to fourth order and to all orders using the results of Gufan and then compared. This theory is applied to Calcite (Roverline3c) to determine all possible continuous commensurate phase transitions.

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Flora Of The Lower Cretaceous Cedar Mountain Formation Of Utah And Colorado; Part Iii, Icacinoxylon Pittiense N. Sp., William D. Tidwell, Gregory F. Thayn, W. L. Stokes Feb 1985

Flora Of The Lower Cretaceous Cedar Mountain Formation Of Utah And Colorado; Part Iii, Icacinoxylon Pittiense N. Sp., William D. Tidwell, Gregory F. Thayn, W. L. Stokes

Faculty Publications

Icacinoxylon pittiense, a new species of angiospermous wood from the Lower Cretaceous Cedar Mountain Formation of Utah is described and compared with similar fossil and modern woods. It is distinguished from other species of Icacinoxylon by its thick-walled fiber-tracheids with their walls making up at least 50% of the total diameter of the cells, conspicuous bordered pits with obliquely crossing extended apertures on both the tangential and radial walls of its fiber-tracheids, scalariform perforation plates with as few as four or greater than 30 bars, transitional opposite to scalariform pitting on its vessel walls, thick-walled ray cells, and distinct sheath …

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New Shubnikov-De Haas Effects In A Two-Dimensional Electron-Hole System, S. Washburn, Richard A. Webb, E. E. Mendez, L. L. Chang, L. Esaki Jan 1985

New Shubnikov-De Haas Effects In A Two-Dimensional Electron-Hole System, S. Washburn, Richard A. Webb, E. E. Mendez, L. L. Chang, L. Esaki

Faculty Publications

We report the temperature dependence of the Shubnikov–de Haas oscillations from a two-dimensional electron-hole system in GaSb-InAs-GaSb quantum wells at very low temperatures. The samples are double heterostructures containing separate electron and hole layers. The oscillations arising from the electron layer behave regularly with temperature. Additional oscillations, characterized by strong temperature dependence, and relatively large peak widths are believed to arise from the presence of hole layers.

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Interpolating Sequences On Curves, Samih Obaid, D. Rung Jan 1985

Interpolating Sequences On Curves, Samih Obaid, D. Rung

Faculty Publications

We established a condition on boundary curves (ending at points) lying either in the unit disc or the upper half plane which implies that any consecutively separated sequence, in the hyperbolic distance, lying on one of these curves is an interpolating sequence for bounded holomorphic functions.

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Quantum Electrodynamics Based On Self-Energy: Lamb Shift And Spontaneous Emission Without Field Quantization, A. O. Barut, Jean F. Van Huele Jan 1985

Quantum Electrodynamics Based On Self-Energy: Lamb Shift And Spontaneous Emission Without Field Quantization, A. O. Barut, Jean F. Van Huele

Faculty Publications

The theory of radiative processes in quantum theory is formulated on the basis of self-energy, in analogy to classical radiation theory, and is explicitly carried out for the calculation of the Lamb shift and spontaneous emission.

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Absence Of Minimum Metallic Conductivity In Gd(3-X)Vxs4 At Very Low Temperature And Evidence For A Coulomb Gap, S. Washburn, Richard A. Webb, S. Von Molnar, F. Holtzberg Nov 1984

Absence Of Minimum Metallic Conductivity In Gd(3-X)Vxs4 At Very Low Temperature And Evidence For A Coulomb Gap, S. Washburn, Richard A. Webb, S. Von Molnar, F. Holtzberg

Faculty Publications

Gd(3-x)vxS4 provides a convenient analog of a compensated semiconductor in which, for x≃0.3, the mobility edge can be tuned smoothly through the Fermi energy by the application of a magnetic field. The results of a search for a minimum metallic conductivity demonstrate that, down to T=6 mK, the metal-insulator transition is smooth. In the insulating regime, the temperature dependence of the conductivity was more consistent with the theory of mutual interactions than with the theory of pure localization.

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Six Copyright Theories For The Protection Of Computer Object Programs, I. Trotter Hardy Oct 1984

Six Copyright Theories For The Protection Of Computer Object Programs, I. Trotter Hardy

Faculty Publications

No abstract provided.

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Magnetoresistance Of Small, Quasi-One-Dimensional, Normal-Metal Rings And Lines, C. P. Umbach, S. Washburn, R. B. Laibowitz, Richard A. Webb Oct 1984

Magnetoresistance Of Small, Quasi-One-Dimensional, Normal-Metal Rings And Lines, C. P. Umbach, S. Washburn, R. B. Laibowitz, Richard A. Webb

Faculty Publications

The magnetoresistance of sub-0.4-μm-diam Au and Au60Pd40 rings was measured in a perpendicular magnetic field at temperatures as low as 5 mK in search of simple, periodic resistance oscillations that would be evidence of flux quantization in normal-metal rings. However, instead of simple oscillations, a very complex structure developed in the magnetoresistance at low temperatures. Fourier analysis of all the data did not reveal convincing evidence for flux quantization in the rings. Complex structure similar to that observed in the rings was also found in the magnetoresistance of short, narrow, Au and Au60Pd …

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Characterization Of Glycated Proteins By 13C Nmr Spectroscopy, Carolyn I. Neglia, Helga J. Cohen, Albert R. Garber, Suzanne R. Thorpe, John W. Baynes Sep 1984

Characterization Of Glycated Proteins By 13C Nmr Spectroscopy, Carolyn I. Neglia, Helga J. Cohen, Albert R. Garber, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

13C NMR spectroscopy has been used to characterize Amadori (ketoamine) adducts formed by reaction of [2-13C]glucose with free amino groups of protein. The spectra of glycated proteins were acquired in phosphate buffer at pH 7.4 and were interpreted by reference to the spectra of model compounds, N alpha-formyl-N epsilon-fructose-lysine and glycated poly-L-lysine (GlcPLL). The anomeric carbon region of the spectrum (approximately 90-105 ppm) of glycated cytochrome c was superimposable on that of N alpha-formyl-N epsilon-fructose-lysine, and contained three peaks characteristic of the alpha- and beta-furanose and beta-pyranose anomers of Amadori adducts to peripheral lysine residues on protein (pK alpha approximately …

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Deformation And Linkage Of Gorenstein Algebras, Andrew R. Kustin, Matthew Miller Aug 1984

Deformation And Linkage Of Gorenstein Algebras, Andrew R. Kustin, Matthew Miller

Faculty Publications

General double linkage of Gorenstein algebras is defined. Rigidity, genericity, and regularity up to codimension six all pass across general double linkage. Rigid strongly unobstructed codimension four Gorenstein algebras which lie in different Herzog classes are produced.

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The Expectation Of Success Using A Monte Carlo Factoring Method – Some Statistics On Quadratic Class Numbers, Duncan A. Buell Jul 1984

The Expectation Of Success Using A Monte Carlo Factoring Method – Some Statistics On Quadratic Class Numbers, Duncan A. Buell

Faculty Publications

A method has been proposed for factoring an integer N by using the structure of the class groups of quadratic fields of radicand – kN for various small multipliers k. We discuss the method and an implementation of the method, and various theoretical questions which have an impact on the practical use of the method in factoring. Some of the theoretical questions relate to the nature of class numbers and class groups; we present extensive statistical results on the class numbers and class groups of imaginary quadratic fields.

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Multiplicities For Evaporative 4he Emission In Heavy Ion Reactions: Relationships To Spin And Lifetime Expectancy Of The Composite Nucleus, N. N. Ajitanand, John M. Alexander, H. Delagrange, E. Duek, D. Ø. Eriksen, D. Guerreau, Morton Kaplan, M. Kildir, L. Kowalski, R. Lacey, D. Logan, D. J. Moses, Graham F. Peaslee, Louis C. Vaz, M. S. Zisman Jun 1984

Multiplicities For Evaporative 4he Emission In Heavy Ion Reactions: Relationships To Spin And Lifetime Expectancy Of The Composite Nucleus, N. N. Ajitanand, John M. Alexander, H. Delagrange, E. Duek, D. Ø. Eriksen, D. Guerreau, Morton Kaplan, M. Kildir, L. Kowalski, R. Lacey, D. Logan, D. J. Moses, Graham F. Peaslee, Louis C. Vaz, M. S. Zisman

Faculty Publications

Multiplicities are compared for4He evaporation in reactions of40Ar and56Fe projectiles (8.5 MeV/u) with withnatAg and238U targets. Coincidence requirements involving fusion-fission and projectile-like fragments have been used to select separate entrance-channel spin zones. Evaporation-like4He emission from the composite nuclei is shown to be large for mean spins ≦100ℏ, and to decrease dramatically with increasing spin. Coincidence measurements between two4He particles have also been studied for40Ar+natAg. This requirement is shown to select reactions that lead to evaporation residues and therefore to a zone of relatively low spin. The shapes of the4He spectra provide an interesting probe of the mechanism and also of …

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On The Differentiability Of Functions In Rn, Ronald A. Devore, Robert C. Sharpley Jun 1984

On The Differentiability Of Functions In Rn, Ronald A. Devore, Robert C. Sharpley

Faculty Publications

No abstract provided.

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Isotropy Group Description Of A Phase Transition In Nano3, W. Scott Stornetta, Dorian M. Hatch Jun 1984

Isotropy Group Description Of A Phase Transition In Nano3, W. Scott Stornetta, Dorian M. Hatch

Faculty Publications

Predictions of the possible post-transition symmetries of an R 3c zone center continuous phase transition are made using recent extensions of the Landau theory. The Landau theory is summarized and direct group theoretical methods are applied to the R 3c phase. General techniques for solving systems of nonlinear polynomial equations are reviewed and these techniques are applied to the minimization of the free energy F for the aforementioned possible symmetries. The results of the direct methods and the minimization procedures are shown to be compatible. It is shown that the transition to R 3c in NaNO3 is consistent with the …

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Error-Bounds For Gaussian Quadrature And Weighted-L1 Polynomial Approximation, Ronald A. Devore, L R. Scott Apr 1984

Error-Bounds For Gaussian Quadrature And Weighted-L1 Polynomial Approximation, Ronald A. Devore, L R. Scott

Faculty Publications

Error bounds for Gaussian quadrature are given in terms of the number of quadrature points and smoothness properties of the function whose integral is being approximated. An intermediate step involves a weighted-L' polynomial approximation problem which is treated in a more general context than that specifically required to bound the Gaussian quadrature error.

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Weak Localization Of Two-Dimensional Conduction Holes, S. Washburn, Richard A. Webb, E. E. Mendez, L. L. Chang, L. Esaki Mar 1984

Weak Localization Of Two-Dimensional Conduction Holes, S. Washburn, Richard A. Webb, E. E. Mendez, L. L. Chang, L. Esaki

Faculty Publications

We report transport measurements which we interpret as weak localization of two-dimensional conduction holes in a GaSb-InAs-GaSb quantum-well structure. This system is unique in that it has parallel conduction channels containing both holes and electrons. The longitudinal resistance of the sample was measured for temperatures between 0.006 and 25 K; the magnetoresistance was measured in a perpendicular magnetic field. Weak localization of the holes was indicated by negative magnetoresistance and by a large logarithmic correction to the conductivity.

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Velocity Measurements Of Humans By Computers, J. B. Rafert, R. C. Nicklin Jan 1984

Velocity Measurements Of Humans By Computers, J. B. Rafert, R. C. Nicklin

Faculty Publications

Distance and time, two fundamental quantities, are discussed early in most introductory physics courses. By dividing a change in distance by time to get velocity, and by dividing a change in velocity by time to get acceleration, two more important quantities result. With these the real world of automobiles and jet planes and applications of Newton's second law is available for interpretation from an analytical point of view. In order to get students thinking reliably about these important ideas it seems important to have direct measurements of distance and time over short enough intervals to talk sensibly about "instantaneous" velocities.

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The Synthesis And Characterization Of Some Fluoride Perovskites, An Undergraduate Experiment In Solid State Chemistry, Richard H. Langley, Colleen K. Schmitz, Maureen B. Langley Jan 1984

The Synthesis And Characterization Of Some Fluoride Perovskites, An Undergraduate Experiment In Solid State Chemistry, Richard H. Langley, Colleen K. Schmitz, Maureen B. Langley

Faculty Publications

In light of the increasing importance of solid state chemistry, an experiment dealing with at least some aspects of this rapidly expanding area should he included in advanced chemistry laboratories. Herein is described one of the experiments that we have developed to meet this need. This experiment was designed for a senior level integrated chemistry lab taken by all our chemistry majors. Normally six to eight hours are needed to complete this experiment. This experiment deals with the synthesis and characterization of a perovskite. Perovskites were chosen because compounds with this structure are important in solid state technology, and since …

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Cenozoic Tectonic History Of The Sierra De Perija, Venezuela- Colombia, And Adjacent Basins, James N. Kellogg Jan 1984

Cenozoic Tectonic History Of The Sierra De Perija, Venezuela- Colombia, And Adjacent Basins, James N. Kellogg

Faculty Publications

The four major Cenozoic tectonic phases in the Sierra de Perija and adjacent basins are the early Eocene tectonic phase, the middle Eocene Caribbean orogeny, the late Oligocene phase, and the late Miocene to present Andean orogeny. Ages of unconformities associated with particularly rapid regional uplift during these phases are early Eocene (53 m.y.), middle Eocene (45 m.y.), late Oligocene (25 m.y.), and Pliocene (3 m.y.). Northwest-southeast compression may have commenced in the Perija and the Maracaibo Basin as early as the early Eocene. By the early Eocene the Macoa-Totumo arch had begun to to form during intense alpine-type folding …

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13C Nmr Investigation Of Nonenzymatic Glucosylation Of Protein, Carolyn I. Neglia, Helga J. Cohen, Albert R. Garber, Paul D. Ellis, Suzanne R. Thorpe, John W. Baynes Dec 1983

13C Nmr Investigation Of Nonenzymatic Glucosylation Of Protein, Carolyn I. Neglia, Helga J. Cohen, Albert R. Garber, Paul D. Ellis, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Nonenzymatic glucosylation of protein is initiated by the reversible condensation of glucose in its open chain form with the amino groups on the protein. The initial product is an aldimine (Schiff base) which cyclizes to the glycosylamine derivative. The aldimine can undergo a slow Amadori rearrangement to yield the relatively stable ketoamine adduct which is structurally analogous to fructose. 13C NMR has been used to characterize these early products of nonenzymatic glucosylation, using RNase A as a model protein. C-1 of the beta-pyranose anomer of the glycosylamine was identified at 88.8 ppm in the spectrum of RNase glucosylated approximately 1:1 …

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On First Countable, Countably Compact Spaces. I: (Omega-1,Omega-1-Star)-Gaps, Peter J. Nyikos, Jerry E. Vaughan Oct 1983

On First Countable, Countably Compact Spaces. I: (Omega-1,Omega-1-Star)-Gaps, Peter J. Nyikos, Jerry E. Vaughan

Faculty Publications

No abstract provided.

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Magnetic Field Behavior Of A Josephson-Junction Array: Two-Dimensional Flux Transport On A Periodic Substrate, Richard A. Webb, Richard F. Voss, G. Grinstein, P. M. Horn Aug 1983

Magnetic Field Behavior Of A Josephson-Junction Array: Two-Dimensional Flux Transport On A Periodic Substrate, Richard A. Webb, Richard F. Voss, G. Grinstein, P. M. Horn

Faculty Publications

This Letter reports measurements down to 3 mK of the magnetic field dependence of the resistance and critical current of a weakly coupled periodic array of Josephson junctions. Below 700 mK the resistance is an oscillatory function of field. The temperature dependence of the resistance for integral numbers of flux quanta per cell suggests the existence of a Kosterlitz-Thouless transition involving the unbinding of defects in the flux lattice.

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Nonenzymatic Glucosylation And Glucose-Dependent Cross-Linking Of Protein, Albert S. Eble, Suzanne R. Thorpe, John W. Baynes Aug 1983

Nonenzymatic Glucosylation And Glucose-Dependent Cross-Linking Of Protein, Albert S. Eble, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

A model system using RNase A has been established for studying the nonenzymatic glucosylation and glucose-dependent cross-linking of protein (Maillard reaction) under physiological conditions in vitro. The rate of glucosylation of RNase was first order in glucose. Glucosylation was accompanied by a comparable decrease in primary amino groups in the protein and lysine recoverable by amino acid analysis. Analysis of glucosylation reaction mixtures by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of mercaptoethanol revealed the time-dependent formation of RNase dimer and trimer. The polymerization reaction was mixed order with respect to glucose concentration, but was approximately first order with …

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Unification Of Ernst-Equation Backlund Transformations Using A Modified Wahlquist-Estabrook Technique; Wahlquist-Estabrook, B. Kent Harrison Aug 1983

Unification Of Ernst-Equation Backlund Transformations Using A Modified Wahlquist-Estabrook Technique; Wahlquist-Estabrook, B. Kent Harrison

Faculty Publications

The three known Backlund transformations for the Ernst equation are derived using a modification of the Wahlquist-Estabrook prolongation procedure. The modification requires that the equation to be studied be cast into a set of differential forms and their exterior derivatives, such that all coefficients are constant (a "CC ideal''). Analysis of the resulting equations produces 16 solutions composed of the three basic transformations combined with identity and other essentially trivial transformations. The group structure of the transformations is discussed. A Backlund transformation (already known) for the Ernst-Maxwell equations can be found by the same method. Promising generalizations are mentioned.

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Gamma-Gamma Angular Correlation Studies For 142ce, A. Wolf, C. Chung, W. B. Walters, R. L. Gill, M. Shmid, R. E. Chrien, Graham F. Peaslee Jul 1983

Gamma-Gamma Angular Correlation Studies For 142ce, A. Wolf, C. Chung, W. B. Walters, R. L. Gill, M. Shmid, R. E. Chrien, Graham F. Peaslee

Faculty Publications

Gamma-gamma angular correlations for several cascades in 142Ce were measured using a four-detector system. In a recent publication the level at 1219 keV was assigned 22+ in contradiction to a previous assignment of 41+. This makes 142Ce completely different from any known nucleus in the same region. It is shown, however, that this level is, in fact, completely consistent with 4+ and is in agreement with systematics.

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Magnetic Moments Of 21+ States As A Probe Of The Effective Proton Boson Number Near The Z = 64 Subshell, A. Wolf, Z. Berant, D. D. Warner, R. L. Gill, M. Shmid, R. E. Chrien, Graham F. Peaslee, H. Yamamoto, John C. Hill, F. K. Wohn, C. Chung, W. B. Walters Mar 1983

Magnetic Moments Of 21+ States As A Probe Of The Effective Proton Boson Number Near The Z = 64 Subshell, A. Wolf, Z. Berant, D. D. Warner, R. L. Gill, M. Shmid, R. E. Chrien, Graham F. Peaslee, H. Yamamoto, John C. Hill, F. K. Wohn, C. Chung, W. B. Walters

Faculty Publications

The g-factors of the 21+ states in 144, 146Ba have been measured using the perturbed angular correlation method. The results are combined with existing experimental data for the neutron-rich Nd, Sm and Gd isotopes and discussed in the framework of the neutron proton interacting boson model. It is shown that the assumption of a drastic change in the effective proton boson number around N = 88, proposed in an earlier study, allows all the results to be explained in a simple framework involving constant values of the boson g-factors.

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A Four-Detector System For Γ - Γ Angular Correlation Studies, A. Wolf, C. Chung, W. B. Walters, Graham Peaslee, R. L. Gill, M. Shmid, V. Manzella, E. Meier, M. L. Stellts, H. I. Liou, R. E. Chrien, D. S. Brenner Mar 1983

A Four-Detector System For Γ - Γ Angular Correlation Studies, A. Wolf, C. Chung, W. B. Walters, Graham Peaslee, R. L. Gill, M. Shmid, V. Manzella, E. Meier, M. L. Stellts, H. I. Liou, R. E. Chrien, D. S. Brenner

Faculty Publications

A multiple detector system for γ - γ coincidence and angular correlation measurements is described. The system consists of four large coaxial Ge detectors set at fixed positions, enabling the measurement of γ - γ coincidences between any pair. Thus, six distinct angles are measured simultaneously. The performance of the system was studied with a 152Eu source. An application for γ - γ correlation studies in 146Ce is described. Systematic errors, if present, are shown to be less than 0.03 and 0.05 for A2 and A4, respectively. The extension of this system to more than four detectors is straightforward.

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