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Collisions of highly stripped ions at MeV energies in gas targets: charge transfer and ionization

Description: Cross sections have been measured for charge transfer and ionization in H/sub 2/ and rare-gas targets by fast, highly ionized carbon, iron, niobium, and lead ions in charge states +3 to +59, with energies in the range 0.1 to 4.8 MeV/amu. Experimental results are compared with classical-trajectory calculations; agreement is generally good. For a given target, the cross sections for net ionization reduce to a common curve when plotted as cross section divided by charge state versus energy per nucleon divided by charge state.
Date: January 1, 1980
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

D/sup -/ production by charge transfer in metal vapors

Description: Fast D/sup -/ ions can be produced from D/sup +/ by multiple charge-transfer collisions in a metal-vapor target. Experimental cross sections and thick-target D/sup -/ yields are presented and discussed. The high D/sup -/ yield experimentally observed from charge transfer in cesium vapor is consistent with recent low-energy cross-section calculations and measurements.
Date: October 1, 1980
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Collisions of fast multicharged ions in gas targets: charge transfer and ionization

Description: Measurements of cross sections for charge transfer and ionization of H/sub 2/ and rare-gas targets have been made with fast, highly stripped projectiles in charge states as high as 59+. We have found an empirical scaling rule for electron-capture cross section in H/sub 2/ valid at energies above 275 keV/amu. Similar scaling might exist for other target gases. Cross sections are generally in good agreement with theory. We have found a scaling rule for electron loss from H in collisions with a fast highly stripped projectile, based on Olson's classical-trajectory Monte-Carlo calculations, and confirmed by measurements in an H/sub 2/ target. We have found a similar scaling rule for net ionization of rare-gas targets, based on Olson's CTMC calculations and the independent-electron model. Measurements are essentially consistent with the scaled cross sections. Calculations and measurements of recoil-ion charge-state spectra show large cross sections for the production of highly charged slow recoil ions.
Date: May 1, 1981
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Production and destruction of D/sup -/ by charge transfer in metal vapors

Description: Experimental studies of D/sup -/ collisions are of interest for basic physics, where experimental results can be used to test theoretical models for charge transfer, and for applications to ion sources for accelerators and for heating magnetically confined plasmas of interest for fusion. The high D/sup -/ yield from charge transfer in a thick cesium-vapor target is consistent with recent cross-section calculations and measurements. Recent theoretical calculations of cross sections in thick alkaline-earth-vapor targets, leading to prediction of a large D/sup -/ yield at low energy, have been partially confirmed in recent measurements, in which a D/sup -/ yield of 50% was observed at a D energy of 500 eV.
Date: June 1, 1981
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Multiple electron capture in close ion-atom collisions

Description: Multiple electron capture is reported for Ca/sup 17 +/ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported.
Date: October 1, 1987
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Multiple-electron processes in fast ion-atom collisions

Description: Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs.
Date: March 1, 1989
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Charge-changing collisions

Description: Recent results for charge-changing collisions of interest for cyclotrons and other particle accelerators are presented. Scaling rules, where available, are emphasized. 45 references, 11 figures.
Date: May 1, 1984
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

New results in atomic physics at the Advanced Light Source

Description: The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.
Date: January 1995
Creator: Schlachter, A. S.
Partner: UNT Libraries Government Documents Department

The Advanced Light Source: A new 1. 5 GeV synchrotron radiation facility at the Lawrence Berkeley Laboratory

Description: The Advanced Light Source (ALS), now under construction at the Lawrence Berkeley Laboratory, is being planned as a national user facility for the production of high-brightness and partially coherent x-ray and ultraviolet synchrotron radiation. The ALS is based on a low-emittance electron storage ring optimized for operation at 1.5 GeV with insertion devices in 11 long straight sections and up to 48 bend-magnet ports. High-brightness photon beams, from less than 10 eV to more than 1 keV, will be produced by undulators, thereby providing many research opportunities in materials and surface science, biology, atomic physics and chemistry. Wigglers and bend magnets will provide high-flux, broad-band radiation at energies to 10 keV. 6 refs., 10 figs., 2 tabs.
Date: June 30, 1989
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Formation of H/sup -/ by charge transfer in alkaline-earth vapors

Description: Progress on the study of H/sup -/ formation by charge transfer in alkaline-earth vapors is reported. The H/sup -/ equilibrium yield in strontium vapor reaches a maximum of 50% at an energy of 250 eV/amu, which is the highest H/sup -/ yield reported to date.
Date: October 1, 1983
Creator: Schlachter, A.S. & Morgan, T.J.
Partner: UNT Libraries Government Documents Department

Proposed neutral-beam diagnostics for fast confined alpha particles in a burning plasma

Description: Diagnostic methods for fast confined alpha particles are essential for a burning plasma experiment. Several methods which use energetic neutral beams have been proposed. We review these methods and discuss system considerations for their implementation.
Date: October 1, 1986
Creator: Schlachter, A. S. & Cooper, W. S.
Partner: UNT Libraries Government Documents Department

An overview of the ALS

Description: This report giving a overview of the parameters, specifications, and scientific programs of the Advance Light Source. (LSP)
Date: February 1, 1991
Creator: Schlachter, A.S. & Robinson, A.
Partner: UNT Libraries Government Documents Department

Scientific program of the Advanced Light Source at LBL

Description: Construction of the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is nearing completion, with operation as a US Department of Energy national user facility scheduled to begin in the spring of 1993. Based on a low-emittance, 1.5-GeV electron storage ring with 10 long straight sections available for insertion devices and, initially, 24 bend-magnet ports, the ALS will be a third-generation source of soft x-ray and ultraviolet (collectively, the XUV) synchrotron radiation. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. The ability to exploit the high spectral brightness of the ALS was the main criterion for PRT selection. In the XUV spectral regions served by the ALS, a major benefit of high brightness will be the ability to achieve spatial resolution in the neighborhood of 200 angstroms in x-ray microscopy and holography and in spatially resolved spectroscopy. Other beneficiaries of high brightness include very-high-resolution spectroscopy, spectroscopy of dilute species, diffraction from very small samples, and time-resolved spectroscopy and diffraction.
Date: October 1, 1991
Creator: Robinson, A.L. & Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

D/sup -/ production by multiple charge-transfer collisions of low-energy D ions and atoms in cesium vapor

Description: The production of D/sup -/ by multiple charge-transfer collisions of a D/sup +/ beam in a cesium-vapor target is considered for D/sup +/ energies above 300 eV. The cross sections relevant to D/sup -/ formation are obtained by a least-squares fit of three-charge-state differential equations to experimental yield curves. Implications for production of intense negative-ion beams are discussed, and speculations are made about extrapolation to lower engeries.
Date: January 22, 1978
Creator: Hooper, E.B. Jr.; Willmann, P.A. & Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

The ALS -- A high-brightness XUV synchrotron radiation source

Description: The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is scheduled to be operational in the spring of 1993 as a US Department of Energy national user facility. The ALS will be a next-generation source of soft x-ray and ultraviolet (XUV) synchrotron radiation. Undulators will provide high-brightness radiation oat photon energies from below 10 eV to above 2 keV; wiggler and bend-magnet radiation will extend the spectral coverage with high fluxes approaching 20 keV. The ALS will support an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. the high brightness will open new areas of research from the materials sciences, such as spatially resolved spectroscopy, to the life sciences, such as x-ray microscopy with element-specific sensitivity. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. 6 refs., 2 figs., 2 tabs.
Date: May 1, 1991
Creator: Robinson, A.L. & Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

The Advanced Light Source: A new tool for research in atomic physics

Description: The Advanced Light Source, a third-generation national synchrotron-radiation facility now under construction at the Lawrence Berkeley Laboratory in Berkeley, California, is scheduled to begin serving qualified users across a broad spectrum of research areas in the spring of 1993. Undulators will generate high-brightness, partially coherent, plane polarized, soft-x-ray and ultraviolet (XUV) radiation from below 10 eV to above 2 keV. Wigglers and bend magnets will generate high fluxes of x-rays to photon energies above 10 keV. The ALS will have an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. 7 refs., 3 figs.
Date: September 1, 1990
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

A neutral-beam diagnostic for fast confined alpha particles in a burning plasma: Application on CIT (Compact Ignition Tokamak)

Description: Diagnostic methods for fast confined alpha particles are essential for a burning-plasma experiment. We review one- and two-electron-capture methods using energetic neutral beams, and provide quantitative estimates of signal level for a two-electron-capture method applicable to CIT. The best probe is a ground-state helium-atom beam because of its relatively good penetration into a CIT plasma and the large cross section for two-electron capture; it can be produced in useful quantities from HeH/sup +/. We calculate a signal level of the order of 10/sup 7/ counts/s for 100 mA of accelerated HeH/sup +/, which is sufficient to allow time-resolved measurements of the alpha-particle velocity distribution. Limited position information could be obtained for appropriate access port geometry. This diagnostic is feasible, and we recommend further research and development leading to implementation on CIT. 39 refs., 16 figs., 5 tabs.
Date: October 1, 1987
Creator: Schlachter, A.S.; Stearns, J.W. & Cooper, W.S.
Partner: UNT Libraries Government Documents Department

Scientific program of the Advanced Light Source at LBL

Description: Construction of the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is nearing completion, with operation as a US Department of Energy national user facility scheduled to begin in the spring of 1993. Based on a low-emittance, 1.5-GeV electron storage ring with 10 long straight sections available for insertion devices and, initially, 24 bend-magnet ports, the ALS will be a third-generation source of soft x-ray and ultraviolet (collectively, the XUV) synchrotron radiation. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. The ability to exploit the high spectral brightness of the ALS was the main criterion for PRT selection. In the XUV spectral regions served by the ALS, a major benefit of high brightness will be the ability to achieve spatial resolution in the neighborhood of 200 angstroms in x-ray microscopy and holography and in spatially resolved spectroscopy. Other beneficiaries of high brightness include very-high-resolution spectroscopy, spectroscopy of dilute species, diffraction from very small samples, and time-resolved spectroscopy and diffraction.
Date: October 1, 1991
Creator: Robinson, A. L. & Schlachter, A. S.
Partner: UNT Libraries Government Documents Department

Third-generation synchrotron light sources

Description: X rays are a powerful probe of matter because they interact with electrons in atoms, molecules, and solids. They are commonly produced by relativistic electrons or positrons stored in a synchrotron. Recent advances in technology are leading to the development of a new third generation of synchrotron radiation sources that produce vacuum-ultraviolet and x-ray beams of unprecedented brightness. These new sources are characterized by a very low electron-beam emittance and by long straight sections to accommodate permanent-magnet undulators and wigglers. Several new low-energy light sources, including the Advanced Light Source, presently under construction at the Lawrence Berkeley Laboratory, and ELETTRA, presently being constructed in Trieste, will deliver the world`s brightest synchrotron radiation in the VUV and soft x-ray regions of the spectrum. Applications include atomic and molecular physics and chemistry, surface and materials science, microscopy, and life sciences.
Date: September 1, 1993
Creator: Schlachter, A. S. & Wuilleumier, F. J.
Partner: UNT Libraries Government Documents Department