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Articles 1291 - 1320 of 1933
Full-Text Articles in Physics
Defect Structure Of Y1-Ycaymno3 And La1-Ycaymno3. I. Electrical Properties, J. W. Stevenson, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin
Defect Structure Of Y1-Ycaymno3 And La1-Ycaymno3. I. Electrical Properties, J. W. Stevenson, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
Electrical conductivity and the Seebeck coefficient of compositions in the system Y1-yCayMnO3 and La1-yCayMnO3 were studied to determine the mechanism of electrical transport and defect structure. Electrical conduction appeared to occur via a small polaron hopping mechanism for compositions with 0.30 ≤ y ≤ 0.80. The Seebeck coefficient data did not support the assumption that Mn is present in Cadoped Mn perovskites only in the +3 and +4 valence states. A new defect model was developed which includes the thermally excited disproportion of Mn3+ and Mn4+ pairs. The …
The Light Ion Lmf And Its Relevance To Ife, Ronald E. Olson, G. O. Allshouse, D. L. Cook, T. R. Lockner, M. G. Mazarakis, C. L. Olson, D. L. Smith
The Light Ion Lmf And Its Relevance To Ife, Ronald E. Olson, G. O. Allshouse, D. L. Cook, T. R. Lockner, M. G. Mazarakis, C. L. Olson, D. L. Smith
Physics Faculty Research & Creative Works
The inertial confinement fusion (ICF) program at Sandia National Laboratories (SNL) is directed toward validating light ions as an efficient driver for ICF defense and energy applications. The light ion laboratory microfusion facility (LMF) is envisioned as a facility in which high gain ICF targets could be developed and utilized in defense-related experiments. The relevance of LMF technology to eventual inertial fusion energy (IFE) applications is assessed via a comparison of LMF technologies with those projected in the Light Ion Beam Reactor Assessment (LIBRA) conceptual reactor design study
Velocity Dependence Of One- And Two-Electron Processes In Intermediate-Velocity Ar16++He Collisions, W. Wu, J. P. Giese, I. Ben-Itzhak, C. L. Cocke, P. Richard, M. Stockli, R. Ali, H. Schöne, Ronald E. Olson
Velocity Dependence Of One- And Two-Electron Processes In Intermediate-Velocity Ar16++He Collisions, W. Wu, J. P. Giese, I. Ben-Itzhak, C. L. Cocke, P. Richard, M. Stockli, R. Ali, H. Schöne, Ronald E. Olson
Physics Faculty Research & Creative Works
We report investigations of one- and two-electron processes in the collisions of 0.9-keV/u to 60-keV/u (vp=0.19-1.55 a.u.) Ar16+ ions with He targets. The cross sections for these processes were measured by observing the final charges of the Ar ions and the recoiling target ions in coincidence. The average Q values for the capture channels were determined by measuring the longitudinal momenta of the recoiling target ions. Single capture (SC) is the dominant process and is relatively independent of the projectile energy. The two-electron transfer-ionization (TI) process is the next largest and slowly increases with projectile energy. The Q values …
Azimuthal Angular Dependence Of Recoil-Ion And Electron Emission In 0.5-Mev P + He Collisions, R. Dörner, J. Ullrich, Ronald E. Olson, O. Jagutzki, H. Schmidt-Böcking
Azimuthal Angular Dependence Of Recoil-Ion And Electron Emission In 0.5-Mev P + He Collisions, R. Dörner, J. Ullrich, Ronald E. Olson, O. Jagutzki, H. Schmidt-Böcking
Physics Faculty Research & Creative Works
Measurements and n-body classical-trajectory Monte Carlo calculations are presented for the dependence of recoil-ion emission on the azimuthal angle between a projectile and a recoil ion. From the measured momenta of the projectile and the recoil ion, the dependence of the electron emission on the azimuthal angle between projectile and electron is deduced. The recoil ions are found to be emitted to the opposite direction of the scattered projectile only for scattering angles larger than 1 mrad, while for smaller scattering angles, the momentum of the emitted electron results in a broad azimuthal angular distribution of the recoil ions. For …
Measurements Of Recoil Ion Longitudinal Momentum Transfer In Multiply Ionizing Collisions Of Fast Heavy Ions With Multielectron Targets, V. Frohne, S. Cheng, R. Ali, M. Raphaelian, C. L. Cocke, R. (Ronald) E. Olson
Measurements Of Recoil Ion Longitudinal Momentum Transfer In Multiply Ionizing Collisions Of Fast Heavy Ions With Multielectron Targets, V. Frohne, S. Cheng, R. Ali, M. Raphaelian, C. L. Cocke, R. (Ronald) E. Olson
Physics Faculty Research & Creative Works
The longitudinal momentum transfer to the recoil ion in collisions of 1 MeV/amu bare F ions with Ne are resolved for final charge states of both projectile and recoil ions. We observe the recoil to be thrown backwards in electron-capture events, reflecting the physical impact of the electron translation factor. The size of the momentum transfer is in agreement with classical trajectory Monte Carlo calculations for low charge state recoil ions but not for high charge state recoil ions. © 1993 The American Physical Society.
Strong Velocity Dependence Of Electron Capture In Collisions Between Aligned Na*(3p) And He2+, A. R. Schlatmann, R. Hoekstra, R. Morgenstern, Ronald E. Olson, J. Pascale
Strong Velocity Dependence Of Electron Capture In Collisions Between Aligned Na*(3p) And He2+, A. R. Schlatmann, R. Hoekstra, R. Morgenstern, Ronald E. Olson, J. Pascale
Physics Faculty Research & Creative Works
By analyzing spectra of emitted photons, we have studied state-selective electron capture in collisions of He2+ on aligned Na*(3p) atoms that span the "velocity-matching" energy between projectile and target electron. We find a strong dependence of the capture cross sections on the Na*(3p) orbital alignment, i.e., aligned perpendicular or parallel to the ion beam direction. The preference changes from perpendicular to parallel at a velocity close to the classical orbital velocity of the 3p electron. Classical-trajectory Monte Carlo calculations reproduce this striking energy dependence. © 1993 The American Physical Society.
The Light-Ion Pulsed Power Induction Accelerator For The Laboratory Microfusion Facility (Lmf), Ronald E. Olson, J. Boyes, M. G. Mazarakis, D. L. Smith, L. F. Bennett, T. R. Lockner, J. W. Poukey
The Light-Ion Pulsed Power Induction Accelerator For The Laboratory Microfusion Facility (Lmf), Ronald E. Olson, J. Boyes, M. G. Mazarakis, D. L. Smith, L. F. Bennett, T. R. Lockner, J. W. Poukey
Physics Faculty Research & Creative Works
In order to initiate ignition and substantial energy yield from an inertial confinement fusion target (ICF), a light-ion pulse of ~700 TW peak power and 15-20 ns duration is required. The preconceptual design presented provides this power. The HERMES-III technology of linear inductive voltage addition in a self-magnetically insulated transmission line (MITL) is utilized to generate the 25-36 MV peak voltage needed for lithium ion beams. The 15-20 MA ion current is achieved by utilizing many accelerating modules in parallel. The lithium ion beams are produced in two-stage extraction diodes. To provide the two separate voltage pulses required by the …
The Lmf Triaxial Mitl Voltage Adder System, Ronald E. Olson, M. G. Mazarakis, D. L. Smith, L. F. Bennett, T. R. Lockner, J. W. Poukey
The Lmf Triaxial Mitl Voltage Adder System, Ronald E. Olson, M. G. Mazarakis, D. L. Smith, L. F. Bennett, T. R. Lockner, J. W. Poukey
Physics Faculty Research & Creative Works
No abstract provided.
Extrapolation Procedures In Mott Electron Polarimetry, Timothy James Gay, M. A. Khakoo, J. A. Brand, J. E. Furst, W. V. Meyer, W. M.K.P. Wijayaratna, F. B. Dunning
Extrapolation Procedures In Mott Electron Polarimetry, Timothy James Gay, M. A. Khakoo, J. A. Brand, J. E. Furst, W. V. Meyer, W. M.K.P. Wijayaratna, F. B. Dunning
Physics Faculty Research & Creative Works
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 …
Calculation Of The Residual Resistivity And The Thermoelectric Power Of Sp Impurities In Silver, Thomas Vojta, Ingrid Mertig, Rudolf Zeller
Calculation Of The Residual Resistivity And The Thermoelectric Power Of Sp Impurities In Silver, Thomas Vojta, Ingrid Mertig, Rudolf Zeller
Physics Faculty Research & Creative Works
We present ab initio calculations for the residual resistivity and the thermopower of sp impurities in silver. The calculations are based on density-functional theory and the Korringa-Kohn-Rostoker Greens-function method. The linearized Boltzmann equation is solved by means of a Fermi-surface harmonic expansion to calculate the residual resistivity, taking into account the anisotropic electronic properties of the dilute alloy. The thermoelectric power was obtained from the energy dependence of the residual resistivity by means of Mott's formula. The results are in satisfying agreement with highly precise experimental results and confirm experimentally obtained deviations from a quadratic dependence on the valence difference …
Mott Electron Polarimetry, Timothy James Gay, F. B. Dunning
Mott Electron Polarimetry, Timothy James Gay, F. B. Dunning
Physics Faculty Research & Creative Works
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 …
Production Of A High-Density State-Selected Metastable Neon Beam, J. A. Brand, J. E. Furst, Timothy James Gay, Laird D. Schearer
Production Of A High-Density State-Selected Metastable Neon Beam, J. A. Brand, J. E. Furst, Timothy James Gay, Laird D. Schearer
Physics Faculty Research & Creative Works
We have developed a high-density source of metastable neon and have selectively quenched both metastable species using a standing-wave dye laser. The source is compact, stable, and produces an average intensity of 3.6x1014 sr-1 s-1 and a density on target of 7.7x106 cm-3.
Classical Description And Calculation Of Ionization In Collisions Of 100 Ev Electrons And Positrons With He And H2, D. R. Schultz, L. Meng, Ronald E. Olson
Classical Description And Calculation Of Ionization In Collisions Of 100 Ev Electrons And Positrons With He And H2, D. R. Schultz, L. Meng, Ronald E. Olson
Physics Faculty Research & Creative Works
In order to explore the range of applicability of the classical trajectory Monte Carlo technique concerning the phenomena associated with light-particle impact of atoms and molecules we present calculations of the singly and doubly differential cross sections for 100 eV electron and positron impact of He and H2 Through comparison with experimental measurements it is noted in what regimes of ejection energy and angle the classical model describes reasonably the process of ionization by electrons. We find that reasonable agreement is obtained regarding the integrated (singly differential and total) cross sections while the features of the doubly differential cross …
A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Nd₂Fe₁₇ And Nd₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Nd₂Fe₁₇ And Nd₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
Chemistry Faculty Research & Creative Works
The Mössbauer spectra of Nd2Fe17 and Nd 2Fe17N2.6 have been measured at various temperatures between 78 and 295 K and analyzed with a model that is based on the Wigner-Seitz cell environment of each iron site, the orientation of the magnetization, and the magnetic moments as determined from either neutron-diffraction measurements or band-structure calculations. Upon nitrogenation of Nd2Fe17, the weighted average isomer shift increases from 0.060 to 0.164 mm/s and further the isomer shifts of the four crystallographically distinct sites increase in agreement with the increase observed in their …
Line Emission From C⁶⁺, O8+ + Li Electron Capture Collisions, Ronald E. Olson, J. Pascale, R. Hoekstra
Line Emission From C⁶⁺, O8+ + Li Electron Capture Collisions, Ronald E. Olson, J. Pascale, R. Hoekstra
Physics Faculty Research & Creative Works
Electron capture cross sections to nl sublevels have been calculated for 1-10keVu−1 collisions of C6+ and O8+ projectiles on a Li target. The classical trajectory Monte Carlo method has been employed with the initial phase distributions for the Li(2s) target obtained from Hartree-Fock calculations. The cross sections are found to maximize at π = 7 for C6+ and n = 8−9 for O8+. The nl cross sections were used to calculate Δ n = 1 line emission cross sections. Comparison of these cross sections with the experimental results of Wolfruni et al indïoitçs good …
State-Selective Capture In Collisions Of Protons With Noble Gases, Michael Schulz, D. M. Blankenship, S. W. Bross, A. D. Gaus, Timothy Gay, W. T. Htwe, John T. Park, Jerry Peacher
State-Selective Capture In Collisions Of Protons With Noble Gases, Michael Schulz, D. M. Blankenship, S. W. Bross, A. D. Gaus, Timothy Gay, W. T. Htwe, John T. Park, Jerry Peacher
Physics Faculty Research & Creative Works
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.
Diffraction In The Binary Encounter Electron Peak Observed In Collisions Of 0.6 Mev Amu⁻¹ I7+, I23+ And Au11+ Projectiles With He And Ar, W. Wolff, J. L. Shinpaugh, H. E. Wolff, Ronald E. Olson, Jee-Ching Wang, S. Lencinas, D. Piscevic, R. Herrmann, H. Schmidt-Böcking
Diffraction In The Binary Encounter Electron Peak Observed In Collisions Of 0.6 Mev Amu⁻¹ I7+, I23+ And Au11+ Projectiles With He And Ar, W. Wolff, J. L. Shinpaugh, H. E. Wolff, Ronald E. Olson, Jee-Ching Wang, S. Lencinas, D. Piscevic, R. Herrmann, H. Schmidt-Böcking
Physics Faculty Research & Creative Works
Relative double differential cross sections for electron emission from collisions of 0.6 MeV amu-1I7+and I23+ projectiles with Ar and Au11+projectiles with He were measured for electron energies from 100 eV to 2000 eV and for angles from 0° to 50°. Experimentally observed sudden shifts of the position of the binary encounter peak were interpreted as resulting from quantum interference in the scattering of target electrons from the partially stripped projectile ion. To this end calculations for the elastic scattering of free electrons initially at rest in the laboratory reference frame from the screened …
Absolute Triple Differential Cross Section For Ionization Of Helium Near Threshold, T. Rösel, Jochen Röder, Leslie S. Frost, Kurt Jung, Hendrik Ehrhardt, Stephenie J. Jones, Don H. Madison
Absolute Triple Differential Cross Section For Ionization Of Helium Near Threshold, T. Rösel, Jochen Röder, Leslie S. Frost, Kurt Jung, Hendrik Ehrhardt, Stephenie J. Jones, Don H. Madison
Physics Faculty Research & Creative Works
Absolute measurements with an accuracy of 22% and theoretical results in a distorted-wave Born approximation (DWBA) are reported for the triple-differential cross section for 26.6-eV electron-impact ionization of helium. An apparatus is used that allows all scattering angles to be independently varied for both coplanar and noncoplanar geometries. The measurements are compared with a DWBA calculation that includes exchange distortion in the calculation of the distorted waves, as well as with earlier calculations by Crothers [J. Phys. B 19, 463 (1986)] and Pan and Starace [Phys. Rev. Lett. 67, 185 (1991)]. Emphasis is placed on understanding the mechanisms for near-threshold …
Adiabatic Cooling Of Atoms By An Intense Standing Wave, Jian Chen, J. Greg Story, Jeffrey J. Tollett, Randall G. Hulet
Adiabatic Cooling Of Atoms By An Intense Standing Wave, Jian Chen, J. Greg Story, Jeffrey J. Tollett, Randall G. Hulet
Physics Faculty Research & Creative Works
Lithium atoms channeled in the nodes of an intense standing-wave radiation field are cooled to near the recoil limit by adibatically reducing the radiation intensity. The final momentum distribution has a narrow component with a root-mean-squared momentum of 2ħk in one dimension, where ħk is the momentum of a radiation-field photon. The data are compared with the results of a Monte Carlo simulation using a two-level atom model. This process may be useful for cooling and increasing the phase-space density of atoms confined in a magnetic trap.
Quasi-Discretization Of The Electron Continuum Emitted In Collisions Of 0.6 Mev U−¹ Au11+ With Noble Gases, S. Hagmann, W. Wolff, J. L. Shinpaugh, H. E. Wolf, Ronald E. Olson, C. P. Bhalla, R. Shingal, C. Kelbch, R. Herrmann, O. Jagutzki, R. Dörner, R. Koch, J. Euler, U. Ramm
Quasi-Discretization Of The Electron Continuum Emitted In Collisions Of 0.6 Mev U−¹ Au11+ With Noble Gases, S. Hagmann, W. Wolff, J. L. Shinpaugh, H. E. Wolf, Ronald E. Olson, C. P. Bhalla, R. Shingal, C. Kelbch, R. Herrmann, O. Jagutzki, R. Dörner, R. Koch, J. Euler, U. Ramm
Physics Faculty Research & Creative Works
We have measured relative doubly differential cross sections for electron emission in collisions of 0.6 MeV u−1 Au11+ projectile ions with He, Ne and Ar targets for laboratory electron-detection angles between 17' and 80' and electron energies from 100 eV to well above the classical binary encounter region. The authors observe that, independent of the target Zt, the electron spectra display three characteristic peak-line structures whose energies are nearly invariant with observation angle. These structures are attributed to the diffraction of quasi-free target electrons in the potential of the projectile. © 1992 IOP Publishing Ltd.
Electron Emission From Foils Induced By Energetic Heavy-Ion Impact, R. A. Sparrow, Ronald E. Olson, D. Schneider
Electron Emission From Foils Induced By Energetic Heavy-Ion Impact, R. A. Sparrow, Ronald E. Olson, D. Schneider
Physics Faculty Research & Creative Works
Doubly differential cross sections have been measured and calculated for the electron emission produced by collisions of 3.5 MeV u−1 U38+ on thin carbon foils. The electron emission is observed in both forward and backward directions. Calculations are in reasonable agreement with the experimental results in both shape and absolute magnitude. At intermediate foil thicknesses, a double binary peak structure is observed that is due to 0° binary electrons being elastically scattered to angle θ along with those that are produced at θ and suffer no large-angle scattering events in the foil. Absolute electron yields show that several …
Design And Development Of A Superconducting Induction Motor, Terry Bowness
Design And Development Of A Superconducting Induction Motor, Terry Bowness
Opportunities for Undergraduate Research Experience Program (OURE)
The discovery of high-Tc superconductors has led to the development of a number of experimental superconducting motors. This report documents the design, construction, and methods of evaluating the performance of an induction motor with a high-Tc superconducting rotor. While others have utilized the Meissner effect, our superconducting motor works due to Lenz’s law. In theory such a device will act as an induction motor only during start-up, after which its behavior is more like that of a synchronous machine. With a one-pole copper squirrel cage providing start-up torque two high-Tc discs encased in the rotor core act …
Automated Seebeck Measurements Applied To Conducting Ceramics, J. S. Shapiro
Automated Seebeck Measurements Applied To Conducting Ceramics, J. S. Shapiro
Opportunities for Undergraduate Research Experience Program (OURE)
The Seebeck coefficient (also known as thermopower) is important in the characterization of conducting ceramics because it is very sensitive to the electronic structure. An apparatus was built during the Fall of 1990 and Spring of 1991 which was designed to measure the Seebeck coefficient in small high-resistivity samples in the temperature range from 80 K to 450 K. A reproducible thermocouple-to-sample electrical and thermal contact technique was found to be important to data accuracy but difficult to achieve. The goals of this project were to improve the thermocouple block design to give better thermal and electrical contact with the …
Electron Production In Proton Collisions With Atoms And Molecules: Energy Distributions, M. Eugene Rudd, Yongki Kim, Don H. Madison, Timothy Gay
Electron Production In Proton Collisions With Atoms And Molecules: Energy Distributions, M. Eugene Rudd, Yongki Kim, Don H. Madison, Timothy Gay
Physics Faculty Research & Creative Works
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 …
Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood
Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This second progress report describes the status of the project one and one-half years after the start. The goal of the project is to develop the instrumentation to collect cloud condensation nuclei (CCN) in sufficient amounts to determine their chemical composition, and to survey the CCN composition in different climates through a series of field measurements. Our approach to CCN collection is to first form droplets on the nuclei under simulated cloud humidity conditions, which is the only known method of identifying CCN from the background aerosol. Under cloud chamber conditions, the droplets formed become larger than the surrounding aerosol, …
Mössbauer And Neutron Diffraction Studies Of Y₂(Fe₁₋ₓmnₓ)₁₄B, Oran Allan Pringle, Gaya Kanishka Marasinghe, Gary J. Long, William Joseph James, William B. Yelon, Decai Xie, Fernande Grandjean
Mössbauer And Neutron Diffraction Studies Of Y₂(Fe₁₋ₓmnₓ)₁₄B, Oran Allan Pringle, Gaya Kanishka Marasinghe, Gary J. Long, William Joseph James, William B. Yelon, Decai Xie, Fernande Grandjean
Physics Faculty Research & Creative Works
We have used Mössbauer spectroscopy and neutron diffraction to study a series of Y2(Fe1-xMnx)1 4B samples in the composition range from x=0.0 to 0.4. Y 2(Fe0.6Mn0.4)14B is paramagnetic at both room temperature and 85 K. The iron quadrupole splitting in this paramagnetic compound allows us to place an upper limit on the quadrupole shift in the magnetic Y2(Fe1-xMnx) 14B alloys. Refinement of Y2(Fe 1-xMnx)14B neutron diffraction data have been used to …
Angular-Differential Cross Sections For H(2p) Formation In Intermediate-Energy Proton-Helium Collisions, Denver G. Seely, S. W. Bross, A. D. Gaus, John Wm Edwards, David R. Schultz, Timothy Gay, John T. Park, Jerry Peacher
Angular-Differential Cross Sections For H(2p) Formation In Intermediate-Energy Proton-Helium Collisions, Denver G. Seely, S. W. Bross, A. D. Gaus, John Wm Edwards, David R. Schultz, Timothy Gay, John T. Park, Jerry Peacher
Physics Faculty Research & Creative Works
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. The experimental …
Magnetic Properties Of A Novel Iron Carbide Film, Fe₇C₃X Formed In A Glow Discharge, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, Jun L. Li, George C. Hadjipanayis, William Joseph James
Magnetic Properties Of A Novel Iron Carbide Film, Fe₇C₃X Formed In A Glow Discharge, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, Jun L. Li, George C. Hadjipanayis, William Joseph James
Physics Faculty Research & Creative Works
No abstract provided.
°-Electron Emission In Fast Heavy Ion Atom Collisions, H. Schmidt-Böcking, U. Ramm, G. Kraft, J. Ullrich, H. Berg, C. Kelbch, Ronald E. Olson, R. (Robert) D. Dubois, S. Hagmann, F. Jiazhen
°-Electron Emission In Fast Heavy Ion Atom Collisions, H. Schmidt-Böcking, U. Ramm, G. Kraft, J. Ullrich, H. Berg, C. Kelbch, Ronald E. Olson, R. (Robert) D. Dubois, S. Hagmann, F. Jiazhen
Physics Faculty Research & Creative Works
Biological damages such as mutations, chromosomal aberrations etc. are consequence of biochemical changes mostly in the DNA /1/. With ionizing radiation, these chemical changes are due to primary ionization events and secondary ionization effects caused by the primarily produced electrons. Differences in the biological response of densely ionizing radiation, like heavy charged particles, in comparison to sparsely ionizing radiation, such as X- or γ-rays, are mainly due to the differences in the productions of the so called δ-electrons. Therefore, the emission process of electrons i.e., the cross section for the primary ionization event as well as the energy and angular …
Differential Cross Sections For State-Selective Electron Capture In 25100-Kev Proton-Helium Collisions, D. R. Schultz, C. O. Reinhold, Ronald E. Olson, D. G. Seely
Differential Cross Sections For State-Selective Electron Capture In 25100-Kev Proton-Helium Collisions, D. R. Schultz, C. O. Reinhold, Ronald E. Olson, D. G. Seely
Physics Faculty Research & Creative Works
Cross sections differential in the scattering angle of the projectile are presented for electron capture summed over all states and to the 2s, 2p, 3s, 3p, 4s, and 4p states of hydrogen in 25-, 50-, and 100-keV proton-helium collisions. The classical-trajectory Monte Carlo (CTMC) technique was employed for these calculations as well as to compute total cross sections as a function of impact energy. The latter are compared with experiment to display the behavior of the integral state-selective cross sections in this energy regime. Detailed comparison is also made between the calculated angular differential cross sections and the experimental measurements …