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Full-Text Articles in Physics
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
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.
Electron Production In Proton Collisions With Atoms And Molecules: Energy Distributions, M. Eugene Rudd, Y.-K. Kim, D. H. Madison, Timothy J. Gay
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 …
Mott Electron Polarimetry, Timothy J. Gay, F. B. Dunning
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 …
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
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. The …
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
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 …
Production Of A High-Density State-Selected Metastable Neon Beam, J. A. Brand, J. E. Furst, Timothy J. Gay, L. D. Shearer
Production Of A High-Density State-Selected Metastable Neon Beam, J. A. Brand, J. E. Furst, Timothy J. Gay, L. D. Shearer
Timothy J. Gay Publications
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 3.6 x 1014 sr -1 s -1 and a density on target of 7.7 x 106 cm-3.
An Attempt To Observe Mott Scattering Optically, J. E. Furst, Timothy J. Gay, W. M. K. P. Wijayaratna, K. Bartschat, H. Geesmann, M. A. Khakoo, D. H. Madison
An Attempt To Observe Mott Scattering Optically, J. E. Furst, Timothy J. Gay, W. M. K. P. Wijayaratna, K. Bartschat, H. Geesmann, M. A. Khakoo, D. H. Madison
Timothy J. Gay Publications
We report an attempt to make an optical observation of Matt scattering, involving the first studies of inelastic collisions between polarized electrons and a heavy noble gas. Polarization fractions of light emitted by the 5p56p[5/7],(3D3) state of Xe following impact excitation in an axial collision geometry were measured as a funclion of the incident electron energy, and compared with distorted-wave Bom calculations. The theoretical and experimental results agree qualitatively in the energy range where cascade contributions to the photon signal are small. We failed to measure non-zero values of the linear polarization fraction η …