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Full-Text Articles in Physics

Giant Suppression Of Flux-Flow Resistivity In Heavy-Ion Irradiated Tl2Ba2Ca2Cu3O10 Films: Influence Of Linear Defects On Vortex Transport, R.C. Budhani, M. Suenaga, Sy_Hwang Liou Dec 1992

Giant Suppression Of Flux-Flow Resistivity In Heavy-Ion Irradiated Tl2Ba2Ca2Cu3O10 Films: Influence Of Linear Defects On Vortex Transport, R.C. Budhani, M. Suenaga, Sy_Hwang Liou

Si-Hwang Liou Publications

A large shift of the onset of flux-flow resistivity and the irreversibility line Hirr (T) to higher temperatures is observed in Tl2Ba2Ca2Cu3O10 films containing linear defects created by Ag+21 ion irradiation. The Hirr(T), which has a characteristic ssL shape in highly anisotropic Tl and Bi based cuprates, becomes more like that of YBa2Cu3O7 in the presence of these defects. The Jc at 77 K also shows a large increase as a result of flux localization at the defects. The transport data ...


Characterization Of Boron Carbide Thin Films Fabricated By Plasma Enhanced Chemical Vapor Deposition From Boranes, Sunwoo Lee, John Mazurowski, G. Ramseyer, Peter A. Dowben Nov 1992

Characterization Of Boron Carbide Thin Films Fabricated By Plasma Enhanced Chemical Vapor Deposition From Boranes, Sunwoo Lee, John Mazurowski, G. Ramseyer, Peter A. Dowben

Peter Dowben Publications

We have fabricated boron carbide thin films on Si(111) and other substrates by plasma-enhanced chemical-vapor deposition (PECVD). The PECVD of boron carbides from nido-cage boranes, specially nido-pentaborane(9) (B5H9), and methane ( CH4) is demonstrated. The band gap is closely correlated with the boron to carbon ratio and can range from 0.77 to 1.80 eV and is consistent with the thermal activation barrier of 1.25 eV for conductivity. We have made boron carbide by PECVD from pentaborane and methane that is sufficiently isotropic to obtain resistivities as large as 1010 ...


Katz Model Prediction Of Caenorhabditis Elegans Mutagenesis On Sts-42, Francis A. Cucinotta, John W. Wilson, Robert Katz, Gautam Badhwar Nov 1992

Katz Model Prediction Of Caenorhabditis Elegans Mutagenesis On Sts-42, Francis A. Cucinotta, John W. Wilson, Robert Katz, Gautam Badhwar

Robert Katz Publications

The Katz track structure model has been applied to describe recessive lethal mutagenesis in the nematode Caenorhabditis elegans after exposure to heavy ions. Based on models of the cosmic-ray environment and heavy-ion transport, mutation rates for the International Microgravity Laboratory 1 (IML-1) experiment on the Space Transportation System 42 (STS-42) are predicted and the results are discussed.


Variationally Stable Treatment Of Two- And Three-Photon Detachment Of H- Including Electron-Correlation Effects, Chih-Ray Liu, Bo Gao, Anthony F. Starace Nov 1992

Variationally Stable Treatment Of Two- And Three-Photon Detachment Of H- Including Electron-Correlation Effects, Chih-Ray Liu, Bo Gao, Anthony F. Starace

Anthony F. Starace Publications

A variationally stable, adiabatic hyperspherical treatment of two- and three-photon detachment of H- is presented. Results are compared with analytic predictions of a zero-range potential model of H-. Detailed comparisions are made also with other theoretical results which include the effects of electron correlations. We predict analytically (and demonstrate numerically) an extreme sensitivity of the theoretical predictions to any errors in the value of the electron affinity employed. In an Appendix we show that the low-intensity limit of the Keldysh treatment [Sov. Phys. JETP 20, 1307 (1965)] of detachment of an electron bound in a zero-range potential agrees with the ...


State-Selective Capture In Collisions Of Protons With Noble Gases, M. Schulz, D. M. Blakenship, S. W. Bross, A. D. Gaus, Timothy J. Gay, W. Htwe, J. T. Park, J. L. Peacher Oct 1992

State-Selective Capture In Collisions Of Protons With Noble Gases, M. Schulz, D. M. Blakenship, S. W. Bross, A. D. Gaus, Timothy J. Gay, W. Htwe, J. T. Park, J. L. Peacher

Timothy J. Gay Publications

We have measured coincidences between neutral H atoms and Lyman-α photons for collisions between 50-keV protons and noble gases as a function of the projectile scattering angle. The coincidences are dominated by capture to the 2p state of the projectile. While the total cross sections depend strongly on the target, the shape of the angular distribution of the differential cross sections was found to depend only weakly on that parameter. The data indicate that electrons are captured predominantly from the outermost shell of the target atom for the collision systems studied here.


Stars Classified As Constant In The General Catalog Of Variable Stars, Edward G. Schmidt, John R. Chab, Darwin E. Reiswig Oct 1992

Stars Classified As Constant In The General Catalog Of Variable Stars, Edward G. Schmidt, John R. Chab, Darwin E. Reiswig

Edward Schmidt Publications

Photometric observations have been made of 16 stars classified as constant, CST or CST:, in the General Catalog of Variable Stars. One star, U Tauri, was found to be a rapid irregular variable and three others may vary at a low level. In two cases, FV Delphini and FP Geminorum, the star identified as the variable on published finding charts is not variable but a nearby star did vary. It is suggested that the wrong stars were marked on the charts but the possibility remains that the variables may have exhibited constancy during earlier observations.


Competition Between Ponderomotive And Thermal Forces In Short-Scale-Length Laser Plasmas, X. Liu, Donald P. Umstadter Sep 1992

Competition Between Ponderomotive And Thermal Forces In Short-Scale-Length Laser Plasmas, X. Liu, Donald P. Umstadter

Donald Umstadter Publications

Interactions of intense 400-fs laser pulses with a solid target are studied with time-integrated and time-resolved measurements. The latter are accomplished by means of a pump and probe experiment, in which the motion of the critical surface is measured with 250-fs resolution. It is found that when the average electron quiver energy (mvos2/2) becomes comparable to the electron thermal energy (kTe), the ponderomotive force of the high-intensity laser significantly reduces the thermal expansion of a laser plasma. This study is performed in an interesting regime not easily accessible with longer pulse lasers, in which the electron ...


Arnold M. Karo, John R. Creighton, John R. Hiskes, Fredrick Mcmurphy, John R. Hardy Sep 1992

Arnold M. Karo, John R. Creighton, John R. Hiskes, Fredrick Mcmurphy, John R. Hardy

John R. Hardy Papers

Arnold M. Karo died on 16 June 1991 at age 63, after a yearlong battle with leukemia. He was a theoretical chemist and solid-state physicist with the chemistry and materials science department at Lawrence Livermore National Laboratory.


Magnetization Of Sm-Fe-N Thin Films With In-Plane Anisotropy, D. Wang, George C. Hadjipanayis, David J. Sellmyer Sep 1992

Magnetization Of Sm-Fe-N Thin Films With In-Plane Anisotropy, D. Wang, George C. Hadjipanayis, David J. Sellmyer

David Sellmyer Publications

Sm-Fe-N films have been made by dc magnetron sputtering and heating in-situ in nitrogen atmosphere. It is observed that the anisotropy changes from perpendicular to in-plane by nitrogenation. The Curie temperature is about 380 K. Aspects of structure, hysterisis loops, initial magnetization curves and temperature dependence of coercivity are discussed.


Gas Phase Interstitial Modification Of Rare-Earth Intermetallics, J.M.D. Coey, Ralph Skomski, S. Wirth Sep 1992

Gas Phase Interstitial Modification Of Rare-Earth Intermetallics, J.M.D. Coey, Ralph Skomski, S. Wirth

Ralph Skomski Publications

The gar phase interstitial modification of rare-earth intermetallics is studied. Net reaction energies for nitrogen in Sm2Fe17 and Nd(Fe11T1) are U0 = - 57 kJ/mole and U0 = - 51 kJ/mole, respectively. The equilibrium nitrogen concentration is calculated as function of temperature and gas pressure using a simple lattice gas model.

For nitrogen in Sm2Fe17, refined diffusion parameters D0 (N) = 1.02 mm2/r and Ea(N) = 133 kJ/mole, determined by thermopiezic analysis of the initial stage of nitrogen absorption, are used to calculate nitrogen profiles and the ...


Structures Of Selected Boranes And Carboranes, Sunwoo Lee, Peter A. Dowben, A.T. Wen, A.P. Hitchcock, John A. Glass Jr., James T. Spencer Jul 1992

Structures Of Selected Boranes And Carboranes, Sunwoo Lee, Peter A. Dowben, A.T. Wen, A.P. Hitchcock, John A. Glass Jr., James T. Spencer

Peter Dowben Publications

Nido-pentaborane(9) (B5H9), 1, nido-2,3-diethyl-2,3-dicarbahexaborane(8)[( C2H5)2C2B4H6], 2, nido-decaborane (14) (B10H14), 3, closo- 1,2-dicarbadodecaborane(12) (H2C2B10H10), 4, can be used as possible source compounds for boron and boron carbide thin film deposition. Inner shell electron energy-loss spectroscopy (ISEELS) studies of the boron Is and carbon Is core excitations of gas phase species have been undertaken so as to characterize these molecular precursors at solid surfaces. The near edge structure of ISEELS provides a good ...


Electronic Structure Of Borane Cage Molecules Adsorbed On Si(111), Sunwoo Lee, Dongqi Li, Sophie M. Cendrowski-Guillaume, Peter A. Dowben, F. Keith Perkins, S.P. Frigo, R.A. Rosenberg Jul 1992

Electronic Structure Of Borane Cage Molecules Adsorbed On Si(111), Sunwoo Lee, Dongqi Li, Sophie M. Cendrowski-Guillaume, Peter A. Dowben, F. Keith Perkins, S.P. Frigo, R.A. Rosenberg

Peter Dowben Publications

We compare the valence band photoemission resulting from molecular adsorption of nido-decaborane(14) (B10H14) and nido-2,3-diethyl-2,3-dicarbahexaborane on Si(111) at 100 K. The relative shift of the apparent valence band edge with increasing molecular coverage is consistent with the relative energy difference in the highest occupied molecular orbital for these two molecules as inferred from modified neglect of differential overlap calculations. The results suggest that the screening is very similar, despite the very different molecular structures of these two nido cage molecules.


Magnetization And 57Fe Hyperfine Fields In Y2Fe17Z3- Δ (Z=H, C, Or N) Interstitial Compounds, Qi-Nian Qi, Hong Sun, Ralph Skomski, J.M.D. Coey Jun 1992

Magnetization And 57Fe Hyperfine Fields In Y2Fe17Z3- Δ (Z=H, C, Or N) Interstitial Compounds, Qi-Nian Qi, Hong Sun, Ralph Skomski, J.M.D. Coey

Ralph Skomski Publications

Measured magnetization and 57Fe hyperfine fields at T∼0 K for Y2Fe17 and Y2Fe17Z3- δ , with Z=H, C, or N and δ∼0.5, are analyzed to determine the influence of the interstitial atoms on the 3d magnetism. All are weak ferromagnets with a nearly-full 3d subband, although when Z=N, the magnetic moment of 38.1μB is very close to the fully saturated value of 39.4μB. On a local scale, the order of hyperfine fields Bhf4f (=35 T)> Bhf6g (=33 ...


Crystalline Orientations Of Tl2Ba2Ca2Cu3OΧ Grains On Mgo, Srtio3, And Laalo3 Substrates, Sy_Hwang Liou, C.Y. Wu Jun 1992

Crystalline Orientations Of Tl2Ba2Ca2Cu3OΧ Grains On Mgo, Srtio3, And Laalo3 Substrates, Sy_Hwang Liou, C.Y. Wu

Si-Hwang Liou Publications

Crystalline orientations of Tl2Ba2Ca2Cu3Oχ grains in magnetron sputtered films on MgO (001), SrTiO3 (001), and LaAlO3 (001) substrates were investigated by scanning electron microscopy. In contrast to the nearly single crystalline films on the lattice matched substrates SrTiO3 and LaAlO3, films on the MgO (001) substrate, being polycrystalline in nature, exhibit several preferred in-plane grain orientations. These orientations agree well with a simplified theory of near-coincidence site lattices between Tl2Ba2Ca2Cu3Oχ and MgO.


Selective Area, Synchrotron Radiation Induced, Delta Doping Of Silicon, R.A. Rosenberg, S.P. Frigo, Sunwoo Lee, Peter A. Dowben May 1992

Selective Area, Synchrotron Radiation Induced, Delta Doping Of Silicon, R.A. Rosenberg, S.P. Frigo, Sunwoo Lee, Peter A. Dowben

Peter Dowben Publications

We have used broadband synchrotron radiation to induce selective area surface doping of boron into silicon. The source of the boron was nido-decaborane (B10H14) adsorbed on Si(111) at 100 K. Irradiation caused decomposition of the adsorbed molecule which lead to an enhanced concentration of free boron in the irradiated area. Using Si 2p core level photoelectron spectroscopy, the surface chemical composition and Fermi level position in both the irradiated and unirradiated regions were determined. The downward movement of the Fermi level was greater in the irradiated region than in the unirradiated region, and greater ...


Evidence For The Formation Of Metallic Mercury Overlayers On Si(111), Dongqi Li, Jiandi Zhang, Sunwoo Lee, Peter A. Dowben May 1992

Evidence For The Formation Of Metallic Mercury Overlayers On Si(111), Dongqi Li, Jiandi Zhang, Sunwoo Lee, Peter A. Dowben

Peter Dowben Publications

A strongly chemisorbed Hg species is observed following the adsorption of Hg on Si(111) at 110 K. This strongly chemisorbed Hg species and subsequently weakly chemisorbed Hg species are observed to be metallic in the photoemission final state as determined by resonant photoemission and the reduction of photovoltaic charging. We postulate that the strongly chemisorbed Hg species on Si(111) is more metallic at dilute coverages than Hg adsorbed on Cu(100).


Multiplet Fine Structure Of The Gd And Tb 5p Levels, Dongqi Li, Peter A. Dowben, M. Onellion May 1992

Multiplet Fine Structure Of The Gd And Tb 5p Levels, Dongqi Li, Peter A. Dowben, M. Onellion

Peter Dowben Publications

Fine structure is observed in the photoemission of Gd and Tb 5p levels as a result of multiplet splitting. These splittings are the consequence of different J final states that occur as a result of interactions with partly filled 4f and/or 5d levels.


Demonstrating The Utility Of Boron Based Precursor Molecules For Selective Area Deposition In A Scanning Tunneling Microscope, F. Keith Perkins, M. Onellion, Sunwoo Lee, Peter A. Dowben May 1992

Demonstrating The Utility Of Boron Based Precursor Molecules For Selective Area Deposition In A Scanning Tunneling Microscope, F. Keith Perkins, M. Onellion, Sunwoo Lee, Peter A. Dowben

Peter Dowben Publications

The scanning tunneling microscope (STM) can be used to selectively deposit material from a gaseous precursor compound. Ultra-small (less than a 100 nm across) spatial dimensions for selective area deposition may be achieved by this means. In this paper we outline a scheme for selecting and designing main group cluster compounds and organometallics for this type of selective area deposition using nido-decaborane(l4) as an example.


Angular Distributions For Near-Threshold (E,2E) Processes For H, He, And Other Rare-Gas Targets , Cheng Pan, Anthony F. Starace Apr 1992

Angular Distributions For Near-Threshold (E,2E) Processes For H, He, And Other Rare-Gas Targets , Cheng Pan, Anthony F. Starace

Anthony F. Starace Publications

Distorted-wave calculations of the triply differential cross sections for electron-impact ionization of H, He, Ne, Ar, Kr, and Xe are presented for final-state electrons sharing ≤4 eV excess energy and for the coplanar, θ12=π geometry. Results for H and He targets, presented briefly elsewhere [C. Pan and A. F. Starace, Phys. Rev. Lett. 67, 185 (1991)], are analyzed in greater detail and compared with available experimental and other theoretical results. In particular, for He targets the effects of exchange and of second-order capture processes are exhibited. These are shown to be of lesser importance than other short-range effects ...


Temperature-Dependent Electronic Structure In A Localized-Magnetic-Moment System: Gadolinium, Dongqi Li, Jiandi Zhang, Peter A. Dowben, M. Onellion Apr 1992

Temperature-Dependent Electronic Structure In A Localized-Magnetic-Moment System: Gadolinium, Dongqi Li, Jiandi Zhang, Peter A. Dowben, M. Onellion

Peter Dowben Publications

At normal emission, the bulklike band in gadolinium overlayers on W(110) shifts toward EF from 1.64 eV at 310 K to 1.43 eV at 230 K in photoemission. This is accompanied by an increase of the feature width from 0.8 eV at 320 K to 1.1 eV at 230 K. The surface-state binding energy remains unchanged, though the width increases significantly with increasing temperature. The different effects of temperature upon the photoemission results obtained for the bulklike and surface states are interpreted as magnetic-order-induced band movement and spin mixing, respectively, and are discussed in the ...


Electron Production In Proton Collisions With Atoms And Molecules: Energy Distributions, M. Eugene Rudd, Y.-K. Kim, D. H. Madison, Timothy J. Gay Apr 1992

Electron Production In Proton Collisions With Atoms And Molecules: Energy Distributions, M. Eugene Rudd, Y.-K. Kim, D. H. Madison, Timothy J. Gay

Timothy J. Gay Publications

All known data on the energy distribution of secondary electrons from collisions of protons with atoms and molecules have been reviewed and differential cross sections have been collected. The two experimental methods used to obtain the data are discussed and possible sources of error pointed out. Theoretical treatments are reviewed and several methods of checking the consistency of the data are discussed. Two semiempirical models have been chosen to represent the differential cross sections, and parameters for these models are given which fit the average of the experimental data, subject to known constraints. Recommended values of differential cross sections are ...


Hyperspherical Coordinate Description Of Single- And Multiphoton Processes In Two-Electron Systems, Anthony F. Starace Mar 1992

Hyperspherical Coordinate Description Of Single- And Multiphoton Processes In Two-Electron Systems, Anthony F. Starace

Anthony F. Starace Publications

The purpose of this chapter is to review the use of the adiabatic hyperspherical approximation for the quantitative calculation of single- and multiphoton cross sections of two-electron systems. In Section 2 we provide a brief general orientation to the hyperspherical coordinate representation, the adiabatic approximation, and a diabatic approximation for treating strongly avoided crossings between adiabatic potential curves. In Section 3 we review applications to photoionization and photodetachment processes in He, Be, H, and Ps. In Section 4 we review applications to multiphoton processes in H. Finally, in Section 5 we assess the adiabatic hyperspherical approximation and discuss future prospects ...


Backward Peak In The Electron Spectrum From Collisions Of 70-Kev Protons With A Target From A Hydrogen-Atom Source, M. Eugene Rudd, M. W. Gealy, G. W. Kerby, Iii, Ying-Yuan Hsu Mar 1992

Backward Peak In The Electron Spectrum From Collisions Of 70-Kev Protons With A Target From A Hydrogen-Atom Source, M. Eugene Rudd, M. W. Gealy, G. W. Kerby, Iii, Ying-Yuan Hsu

M. Eugene Rudd Publications

A large, broad peak has been found in the electron energy spectrum from 30 to 100-keV H+ + H collisions. The peak, which is centered at 31 eV, appears only in the backward directions. It is suggested that while the peak is unlikely to come from collisions with atoms in the ground or metastable states, it could arise from collisions with atoms in highly excited states or from autoionizing states of the residual H2 in the target.


Temporary Negative Ions And Vibrational Excitation In Ch3Cl And Cd3Cl, X. Shi, T.M. Stephen, Paul Burrow Mar 1992

Temporary Negative Ions And Vibrational Excitation In Ch3Cl And Cd3Cl, X. Shi, T.M. Stephen, Paul Burrow

Paul Burrow Publications

Electron energy loss spectroscopy is used to study the vibrational modes of CH3Cl and CD3Cl excited through the formation of a temporary negative ion state centered at 3.5 eV. Using symmetry and charge distribution arguments together with the experimentally determined excitation functions for several vibrational modes, we confirm that this resonance results from filling of the 8a1 (C–Cl) σ* molecular orbital. Evidence for a broad higher-lying resonance which we attribute to the unfilled 4e orbital is also presented.


Magnetic Relaxation And Irreversibility In A Superconducting Tl2Ba2Ca2Cu3O10±X Thin Film, V.K. Chan, Sy_Hwang Liou Mar 1992

Magnetic Relaxation And Irreversibility In A Superconducting Tl2Ba2Ca2Cu3O10±X Thin Film, V.K. Chan, Sy_Hwang Liou

Si-Hwang Liou Publications

The magnetic relaxation in a Tl2Ba2Ca2Cu3O10±x superconducting thin film has been measured at a range of temperatures (5–70 K) and field strengths (500–5000 Oe). Measurements reveal that the relaxation obeys a logarithmic time dependence in the time interval 2000 s<t<12 000 s. The relaxation rate is both temperature and field dependent. The average pinning potential U* calculated from the relationship U*=kT/[(-1/Mi)dM/d lnt] is in the range 20–70 meV, which is similar to those of Y-Ba-Cu-O and (Bi,Pb)-Sr-Ca-Cu-O. The anomalous increase of U* at higher temperature is found to be closely related to ...


Three-Dimensional Structure Of The Ordered Phases Of Hg On Cu(001), Wei Li, Jingsu Lin, M. Karimi, Peter A. Dowben, G. Vidali Feb 1992

Three-Dimensional Structure Of The Ordered Phases Of Hg On Cu(001), Wei Li, Jingsu Lin, M. Karimi, Peter A. Dowben, G. Vidali

Peter Dowben Publications

The structures of ordered phases following adsorption of mercury on Cu(001) have been identified using helium-beam scattering and low-energy electron diffraction. We found that three of the four observed ordered submonolayer phases are high-order commensurate phases. The three-dimensional structure of these phases brought about by a periodic variation of the height of the Hg atoms above the Cu(001) plane has been measured. Furthermore, from a combined analysis of helium-beam scattering and angle-resolved photoemission data for a low-density Hg ordered overlayer, we deduce and quantify the departure from the atomic electron distribution of Hg due to adsorption. A model ...


Angular-Differential Cross Sections For H(2P) Formation In Intermediate-Energy Proton-Helium Collisions, D. G. Seely, S. W. Bross, A. D. Gaus, J. W. Edwards, D. R. Schultz, Timothy J. Gay, J. T. Park, J. L. Peacher Feb 1992

Angular-Differential Cross Sections For H(2P) Formation In Intermediate-Energy Proton-Helium Collisions, D. G. Seely, S. W. Bross, A. D. Gaus, J. W. Edwards, D. R. Schultz, Timothy J. Gay, J. T. Park, J. L. Peacher

Timothy J. Gay Publications

Angular-differential cross sections for charge transfer with simultaneous emission of a photon in collisions of protons with helium atoms have been measured. The incident proton energies were 25, 50, and 100 keV and the center-of-mass scattering angles were between 0 and 2.0 mrad. In the experiment, hydrogen atoms that scattered through an angle θ were detected in coincidence with photons emitted perpendicular to the scattering plane with a wavelength between 1140 and 1400 Å. Differential cross sections for capture into the 2p state of the hydrogen atom were determined from the variation in the coincidence signal with θ ...


Mott Electron Polarimetry, Timothy J. Gay, F. B. Dunning Feb 1992

Mott Electron Polarimetry, Timothy J. Gay, F. B. Dunning

Timothy J. Gay Publications

Electron polarimeters based on Mott scattering are extensively used in atomic and molecular, solid state, nuclear, and high-energy physics. This use stems from the increasing realization that much additional information concerning many physical processes can be obtained through spin-dependent measurements. In this review we discuss the basic physics and application of Mott polarimetry. A number of different Mott polarimeter designs are described that illustrate the wide range of operating energies (10 eV-1 MeV) and geometries that can be used in such instruments. The calibration of Mott polarimeters is discussed together with the potential sources of systematic error that can arise ...


The Effect Of Diamagnetic Dilution On The Spin-Phonon Interaction And Scattering Cross Section In Fe1-Xznxf2, Christian Binek Jan 1992

The Effect Of Diamagnetic Dilution On The Spin-Phonon Interaction And Scattering Cross Section In Fe1-Xznxf2, Christian Binek

Christian Binek Publications

The temperature dependences of the first moments of phonon Raman scattering lines are studied for Fe1-xZnxF2. The diamagnetic dilution diminishes the spin-phonon coupling strength of phonons with both A1g and Eg symmetry in proportion to the decrease in the ordering temperature TN. Moreover, the Eg mode shows an asymmetrical lineshape for Zn concentrations x>0.3. It is explained by an unresolved superposition of two modes, one of which is ascribed to perturbed ZnF2 with broken translational symmetry.


Extrapolation Procedures In Mott Electron Polarimetry, Timothy J. Gay, M. A. Khakoo, J. A. Brand, J. E. Furst, W. V. Meyer, W. M. K. P. Wijayaratna, F. B. Dunning Jan 1992

Extrapolation Procedures In Mott Electron Polarimetry, Timothy J. Gay, M. A. Khakoo, J. A. Brand, J. E. Furst, W. V. Meyer, W. M. K. P. Wijayaratna, F. B. Dunning

Timothy J. Gay Publications

In standard Mott electron polarimetry using thin gold film targets, extrapolation procedures must be used to reduce the experimentally measured asymmetries A to the values they would have for scattering from single atoms. These extrapolations involve the dependence of A on either the gold film thickness t or the maximum detected electron energy loss in the target ΔE. Using a concentric cylindrical-electrode Mott polarimeter, we have studied and compared these two types of extrapolations over the electron energy range 20-100 keV. The potential systematic errors which can result from such procedures are analyzed in detail, particularly with regard to the ...