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Sample records for aes auger electron

  1. Effects of Auger electron elastic scattering in quantitative AES

    NASA Astrophysics Data System (ADS)

    Jablonski, Aleksander

    1987-09-01

    The Monte Carlo algorithm was developed for simulating the trajectories of electrons elastically scattered in the solid. The distribution of scattering angles was determined using the partial wave expansion method. This algorithm was used to establish the influence of Auger electron elastic collisions on the results of quantitative AES analysis. The calculations were performed for the most pronounced KLL, L 3 MM and M 5NN Auger transitions. It turned out that due to the elastic collisions the Auger electron signal is decreased by up to 10%. The corresponding decreased of the escape depth of Auger electrons reaches 30% as compared with the value derived from the inelastic mean free path. The values of the inelastic mean free path resulting from the overalyer method may be strongly affected by elastic scattering of Auger electrons.

  2. Positron annihilation induced Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Weiss, Alex; Koymen, A. R.; Mehl, David; Jensen, K. O.; Lei, Chun; Lee, K. H.

    1990-01-01

    Recently, Weiss et al. have demonstrated that it is possible to excite Auger transitions by annihilating core electrons using a low energy (less than 30eV) beam of positrons. This mechanism makes possible a new electron spectroscopy, Positron annihilation induced Auger Electron Spectroscopy (PAES). The probability of exciting an Auger transition is proportional to the overlap of the positron wavefunction with atomic core levels. Since the Auger electron energy provides a signature of the atomic species making the transition, PAES makes it possible to determine the overlap of the positron wavefunction with a particular element. PAES may therefore provide a means of detecting positron-atom complexes. Measurements of PAES intensities from clean and adsorbate covered Cu surfaces are presented which indicate that approx. 5 percent of positrons injected into CU at 25eV produce core annihilations that result in Auger transitions.

  3. Positron annihilation induced Auger electron emission

    SciTech Connect

    Weiss, A.; Jibaly, M.; Lei, Chun; Mehl, D.; Mayer, R.; Lynn, K.G.

    1988-01-01

    We report on measurements of Auger electron emission from Cu and Fe due to core hole excitations produced by the removal of core electrons by matter-antimatter annihilation. Estimates are developed of the probability of positrons annihilating with a 3p electron in these materials. Several important advantages of Positron annihilation induced Auger Electron Spectroscopy (PAES) for surface analysis are suggested. 10 refs., 2 figs.

  4. Evidence for Chirped Auger-Electron Emission

    NASA Astrophysics Data System (ADS)

    Schütte, B.; Bauch, S.; Frühling, U.; Wieland, M.; Gensch, M.; Plönjes, E.; Gaumnitz, T.; Azima, A.; Bonitz, M.; Drescher, M.

    2012-06-01

    Auger decay carries valuable information about the electronic structure and dynamics of atoms, molecules, and solids. Here we furnish evidence that under certain conditions Auger electrons are subject to an energetic chirp. The effect is disclosed in time-resolved streaking experiments on the Xe NOO and Kr MNN Auger decay using extreme-ultraviolet pulses from the free-electron laser in Hamburg as well as from a high-order harmonic laser source. The origin of this effect is found to be an exchange of energy between the Auger electron and an earlier emitted correlated photoelectron. The observed time-dependent spectral modulations are understood within an analytical model and confirmed by extensive computer simulations.

  5. Auger electron spectroscopy as a tool for measuring intramolecular charges of adsorbed molecules

    NASA Astrophysics Data System (ADS)

    Magkoev, T. T.

    A way for the determination of the values of intramolecular charges of adsorbed molecules of some binary dielectrics, based on Auger electron spectroscopy (AES), is proposed. These values can be obtained from the coverage dependences of the ratios of intensities of anion KL 23L 23 and KL 1L 1 Auger transitions, which are sensitive to the amount of charge at the 2p-orbitals. As an example, MgO adsorbed on Mo(110) is presented.

  6. Auger electron spectroscopy as a tool for measuring intramolecular charges of adsorbed molecules

    NASA Astrophysics Data System (ADS)

    Magkoev, T. T.

    1993-10-01

    A way for the determination of the values of intramolecular charges of adsorbed molecules of some binary dielectrics, based on Auger electron spectroscopy (AES), is proposed. These values can be obtained from the coverage dependences of the ratios of intensities of anion KL 23L 23 and KL 1L 1 Auger transitions, which are sensitive to the amount of charge at the 2p-orbitals. As an example, MgO adsorbed on Mo(110) is presented.

  7. The AE-8 trapped electron model environment

    NASA Technical Reports Server (NTRS)

    Vette, James I.

    1991-01-01

    The machine sensible version of the AE-8 electron model environment was completed in December 1983. It has been sent to users on the model environment distribution list and is made available to new users by the National Space Science Data Center (NSSDC). AE-8 is the last in a series of terrestrial trapped radiation models that includes eight proton and eight electron versions. With the exception of AE-8, all these models were documented in formal reports as well as being available in a machine sensible form. The purpose of this report is to complete the documentation, finally, for AE-8 so that users can understand its construction and see the comparison of the model with the new data used, as well as with the AE-4 model.

  8. Angular distributions of molecular Auger electrons: The case of C 1s Auger emission in CO

    SciTech Connect

    Semenov, S. K.; Kuznetsov, V. V.; Cherepkov, N. A.; Bolognesi, P.; Feyer, V.; Lahmam-Bennani, A.; Casagrande, M. E. Staicu; Avaldi, L.

    2007-03-15

    The results of a study of the Auger-electron-photoelectron angular correlations in the case of the C 1s ionization of the CO molecule are presented and compared with theoretical calculations in the Hartree-Fock approximation based on the two-step model. The measurements have been performed at two photon energies, 305 and 318 eV, respectively, and at three angles of photoelectron emission relative to the light polarization vector: namely, 0 degree sign , 30 degree sign , and 60 degree sign . A general agreement is found between theory and experiment for the coincidence angular distributions and the relative magnitudes of the Auger-electron-photoelectron angular correlations. However, both experiment and theory show that the Auger-electron-photoelectron angular correlations are not sufficiently sensitive to the details of the Auger-electron wave function to allow a 'complete' Auger experiment in molecules. On the other hand, our calculations demonstrate that the Auger-electron angular distribution measured in the molecular frame is very sensitive to the individual contributions of different partial waves of the Auger electron. Therefore we conclude that the complete experiment for the Auger decay in molecules can be realized only measuring the Auger-electron angular distributions in the molecular frame.

  9. Kinetic energies to analyze the experimental auger electron spectra by density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Endo, Kazunaka

    2016-02-01

    In the Auger electron spectra (AES) simulations, we define theoretical modified kinetic energies of AES in the density functional theory (DFT) calculations. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. This method is applied to simulate Auger electron spectra (AES) of 2nd periodic atom (Li, Be, B, C, N, O, F)-involving substances (LiF, beryllium, boron, graphite, GaN, SiO2, PTFE) by deMon DFT calculations using the model molecules of the unit cell. Experimental KVV (valence band electrons can fill K-shell core holes or be emitted during KVV-type transitions) AES of the (Li, O) atoms in the substances agree considerably well with simulation of AES obtained with the maximum kinetic energies of the atoms, while, for AES of LiF, and PTFE substance, the experimental F KVV AES is almost in accordance with the spectra from the transitionstate kinetic energy calculations.

  10. An Auger electron spectroscopy study of surface-preparation contaminants

    NASA Technical Reports Server (NTRS)

    Wu, D.; Stephens, R. M.; Outlaw, R. A.; Hopson, P.

    1990-01-01

    There are many cleaning techniques that are presently being employed for surface preparation of materials that are subsequently exposed to ultrahigh vacuum (UHV). Unfortunately, there are virtually no comparative measurements which establish the residual contaminant level of each method. In this report, eleven different cleaning methods, ranging from only detergent cleaning to electrochemical polishing, were applied to identical samples of 347 stainless steel. Two surface conditions, a standard machined surface and a mechanically polished surface, were studied. Auger electron spectroscopy (AES) within a UHV environment was then used to detect the types of contaminants and the magnitudes found on the sample surfaces. It was found that the electrochemical polishing gave the least contaminated surface of all metals studied and that mechanically polished surfaces were significantly cleaner than the as-machined surfaces for any given cleaning method. Furthermore, it was also found that the residual contaminations left by methanol, ethanol, isopropyl alcohol, acetone, and freon finishing rinses are almost the same.

  11. An Auger electron spectroscopy study of surface-preparation contaminants

    NASA Astrophysics Data System (ADS)

    Wu, D.; Stephens, R. M.; Outlaw, R. A.; Hopson, P.

    1990-02-01

    There are many cleaning techniques that are presently being employed for surface preparation of materials that are subsequently exposed to ultrahigh vacuum (UHV). Unfortunately, there are virtually no comparative measurements which establish the residual contaminant level of each method. In this report, eleven different cleaning methods, ranging from only detergent cleaning to electrochemical polishing, were applied to identical samples of 347 stainless steel. Two surface conditions, a standard machined surface and a mechanically polished surface, were studied. Auger electron spectroscopy (AES) within a UHV environment was then used to detect the types of contaminants and the magnitudes found on the sample surfaces. It was found that the electrochemical polishing gave the least contaminated surface of all metals studied and that mechanically polished surfaces were significantly cleaner than the as-machined surfaces for any given cleaning method. Furthermore, it was also found that the residual contaminations left by methanol, ethanol, isopropyl alcohol, acetone, and freon finishing rinses are almost the same.

  12. The inner zone electron model AE-5

    NASA Technical Reports Server (NTRS)

    Teague, M. J.; Vette, J. I.

    1972-01-01

    A description is given of the work performed in the development of the inner radiation zone electron model, AE-5. A complete description of the omnidirectional flux model is given for energy thresholds E sub T in the range 4.0 E sub T/(MeV) 0.04 and for L values in the range 2.8 L 1.2 for an epoch of October 1967. Confidence codes for certain regions of B-L space and certain energies are given based on data coverage and the assumptions made in the analysis. The electron model programs that can be supplied to a user are referred to. One of these, a program for accessing the model flux at arbitrary points in B-L space and arbitrary energies, includes the latest outer zone electron model and proton model. The model AE-5, is based on data from five satellites, OGO 1, OGO 3, 1963-38C, OV3-3, and Explorer 26, spanning the period December 1964 to December 1967.

  13. Auger, zero-energy photoelectron, coincidence spectroscopy (AZEPECO): Chemical-site-selective Auger electron spectroscopy

    SciTech Connect

    Lee, K.; Ji, D.; Hanson, D.M.; Hulbert, S.L.; Kuiper, P.

    1993-12-31

    The Auger electron spectrum associated with decay of a core-hole on the terminal nitrogen and that associated with the central nitrogen of nitrous oxide, N{sub 2}O, are obtained individually through the use of a coincidence technique. Specifically, each of the two Auger electron spectra is obtained by detection of Auger electrons in coincidence with near zero energy (threshold) photoelectrons at the respective ionization thresholds. These zero energy electrons serve to identify the core-ionization continuum associated with the different Auger electrons. The salient features of the experimental spectra are in good agreement with theoretical calculations. The low counting rate generally associated with coincidence experiments, especially in the gas phase, is not encountered because the low energy electrons are collected over a 4{pi} solid angle. Also, velocity discrimination is accomplished by a spatial filter rather than by time-of-flight to utilize the maximum duty cycle of the synchrotron source. These data are believed to be the first examples of chemical-site-selective molecular Auger spectra.

  14. Thickness determination of few-layer hexagonal boron nitride films by scanning electron microscopy and Auger electron spectroscopy

    SciTech Connect

    Sutter, P. Sutter, E.

    2014-09-01

    We assess scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) for thickness measurements on few-layer hexagonal boron nitride (h-BN), the layered dielectric of choice for integration with graphene and other two-dimensional materials. Observations on h-BN islands with large, atomically flat terraces show that the secondary electron intensity in SEM reflects monolayer height changes in films up to least 10 atomic layers thickness. From a quantitative analysis of AES data, the energy-dependent electron escape depth in h-BN films is deduced. The results show that AES is suitable for absolute thickness measurements of few-layer h-BN of 1 to 6 layers.

  15. A universal algorithm for calculating the backscattering factor in Auger-electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Jablonski, A.; Powell, C. J.

    2007-02-01

    We describe a universal Monte Carlo algorithm that can be used for the efficient calculation of backscattering factors (BFs) for quantitative Auger-electron spectroscopy (AES). This algorithm makes use of the continuous slowing-down approximation and the electron stopping power instead of simulation of individual inelastic-scattering events. This approach is attractive because it can be applied to any material with an empirical formula for the stopping power, available data for differential elastic-scattering cross sections, and an empirical formula for inner-shell ionization cross sections. We report BFs for the Si KL 23L 23, Cu L 3M 45M 45, Ag M 5N 45N 45, and Au M 5N 67N 67 Auger transitions in the corresponding elemental solids. These BFs were calculated for normal incidence of the primary beam, primary energies from near threshold for ionization of the relevant core levels to 20 keV, and Auger-electron emission angles of 10°, 60°, and 80°. We found satisfactory agreement between these BFs and values obtained from a more accurate algorithm in which individual inelastic-scattering events were simulated. Percentage deviations between BFs from the two algorithms were <2% for Au, <5% for Ag, <7% for Cu, and <10% for Si for primary energies likely to be used in practical AES. These deviations arise mainly from our use of stopping powers from the empirical formula rather than more reliable values calculated from experimental optical data.

  16. Auger electron spectroscopy and depth profile study of oxidation of modified 440C steel

    NASA Technical Reports Server (NTRS)

    Ferrante, J.

    1974-01-01

    Auger electron spectroscopy (AES) and sputtering were used to study selective oxidation of modified 440C steel. The sample was polycrystalline. Oxidation was performed on initially clean surfaces for pressures ranging from 1 x 10 to the minus 7th power to 1 x 10 to the minus 5th power torr and temperatures ranging from room temperature to 800 C. AES traces were taken during oxidation. In situ sputtering depth profiles are also obtained. A transition temperature is observed in the range 600 to 700 C for which the composition of the outer surface oxide changed from iron oxide to chromium oxide. Heating in vacuum about 5 x 10 to the minus 10 power torr to 700 C causes conversion of the iron oxide surface to chromium oxide.

  17. Specific energy from Auger and conversion electrons of 131I, 188Re-anti-CD20 to a lymphocyte's nucleus

    NASA Astrophysics Data System (ADS)

    Torres-García, E.; Carrillo-Cazares, T. A.

    2011-01-01

    The typical radionuclides used to label anti-CD20 in the treatment of non-Hodgkin's lymphoma are 90Y, 131I, and 188Re, with the emission of beta particles, Auger electrons, and conversion electrons for the latter two. The aim of the present work was to calculate the contribution of high linear energy transfer radiation as Auger electrons (AE) and conversion electrons (CE) of 131I and 188Re-anti-CD20 to mean specific energy into the cell nucleus by Monte Carlo simulation (MCS), so as to infer therapeutic effectiveness on a dosimetric basis. MCS was used to quantify the frequency-mean specific energy into the cell nucleus, where the cell was modeled by two concentric spheres, considering two cell models. The results showed that 10% and 33% of the mean-specific energies (z¯) per disintegration imparted to the cell nucleus for both geometries are due to AE and CE; on the other hand, if the hit of AE and CE occurs, the contribution to (z¯) is about 64% and 86% for 131I and 188Re, respectively. According to the amount of specific energy from AE and CE into the cell nucleus by positive event, they can cause catastrophic effects in the nuclear DNA in the treatment of non-Hodgkin's lymphoma with 131I, 188Re-anti-CD20.

  18. Properties of Auger electrons following excitation of polarized atoms by polarized electrons

    NASA Astrophysics Data System (ADS)

    Kupliauskienė, A.; Tutlys, V.

    2009-01-01

    In non-relativistic approximation, the most general expression for differential cross sections describing the properties of Auger-electron emission induced in the excitation of polarized atoms by polarized electrons is obtained for the first time. The ways of the application of the general expressions suitable for the specific experimental conditions are outlined by deriving the expressions for the asymmetry parameters and the magnetic dichroism of the angular distribution of the Auger electrons as well as of the angular correlations between the scattered and Auger electrons.

  19. Approaches to analyzing insulators with Auger Electron Spectroscopy: Update and Overview

    SciTech Connect

    Baer, Donald R.; Lea, Alan S.; Geller, J.; Hammond, John S.; Kover, L.; Powell, Cedric J.; Seah, M. P.; Suzuki, M.; Watts, J. W.; Wolstenholme, J.

    2010-01-01

    This paper provides an updated overview, intended to be of practical value to analysts, of methods that can be applied to minimize or control the buildup of near surface electrical charge during electron induced Auger electron spectroscopy (AES). Although well developed methods can be highly effective, dealing with insulating or ungrounded samples for which high spatial resolution is needed remains a challenge. Examples of the application of methods involving low energy ion sources and sample thinning using a focused ion beam that can allow high resolution measurements on a variety of samples are highlighted. The physical bases of newer and traditional methods are simply described along with strengths and limitations of the methods. Summary tables indicate which methods apply to almost any spectrometer, which require special instrumental capabilities, and those that require special sample preparation or mounting.

  20. Site-specific Auger electron spectra of ethyl trifluoroacelate molecules studied by magnetic bottle electron spectrometer

    NASA Astrophysics Data System (ADS)

    Iwayama, Hiroshi; Shigemasa, Eiji; Hikosaka, Yasumasa; Nakano, Motoyoshi; Ito, Kenji; Lablanquie, Pascal; Penet, Francis; Andric, Lidija; Selles, Patricia

    2012-11-01

    We performed multielectron coincidence measurements for inner-shell photoionizations of ethyl trifluoroacelate molecules (C4H5F3O2) using a magnetic bottle electron spectrometer. From a two dimensional coincidence map between a photoelectron and Auger electron for C 1s ionizations, we extracted site-specific Auger electron spectra for each carbon site and corresponding binding energy of doubly charged states.

  1. Some strategies for quantitative scanning Auger electron microscopy

    NASA Technical Reports Server (NTRS)

    Browning, R.; Peacock, D. C.; Prutton, M.

    1985-01-01

    The general applicability of power law forms of the background in electron spectra is pointed out and exploited for background removal from under Auger peaks. This form of B(E) is found to be extremely sensitive to instrumental alignment and to fault-free construction - an observation which can be used to set up analyser configurations in an accurate way. Also, differences between N(E) and B(E) can be used to derive a spectrometer transmission function T(E). The questions of information density in an energy-analysing spatially-resolving instrument are addressed after reliable instrumental characterization has been established. Strategies involving ratio histograms, showing the population distribution of the ratio of a pair of Auger peak heights, composition scatter diagrams and windowed imaging are discussed and illustrated.

  2. Oxygen diffusion of anodic surface oxide film on titanium studied by Auger electron spectroscopy. [Oxygen diffusivity

    SciTech Connect

    Wang, P.S.; Wittberg, T.N.; Keil, R.G.

    1982-01-01

    TiO/sub 2/ films of about 1000 A were grown onto titanium foils anodically under galvanostatic conditions at 20 mA/cm/sup 2/ in saturated aqueous solutions of ammonium tetraborate. The samples were then aged at 450, 500, and 550/sup 0/C, and oxygen diffusion was observed by Auger electron spectroscopy (AES) profilings. The oxygen diffusivities were calculated by Fick's Second Law, using the Boltzmann-Matano solution, to be 9.4 x 10/sup -17/, 2.6 x 10/sup -16/, and 1.2 x 10/sup -15/ cm/sup 2//sec at 450, 500, and 550/sup 0/C, respectively. The diffusivities obtained by this method were also compared with those obtained using an exact solution to Fick's Second Law. The activation energy was calculated to be 30 kcal/mole.

  3. Auger electron spectroscopy study of alloy 718 and 304L stainless steel irradiated with 800 MeV protons

    NASA Astrophysics Data System (ADS)

    García-Mazarío, M.; Hernández-Mayoral, M.; Lancha, A. M.

    2001-07-01

    It is well known that radiation produces changes in materials microstructure such as formation of defects, dissolution and redistribution of secondary phases, precipitation of new phases, etc. and changes in the grain boundary microchemistry by a process known as radiation-induced segregation (RIS). This paper describes the grain boundary microchemical characterization of alloy 718 and 304L stainless steel irradiated with high-energy protons at Los Alamos Neutron Science Center (LANSCE), performed by means of Auger electron spectroscopy (AES). In addition, non-irradiated alloy 718 was characterized as reference. The Auger results showed that as a consequence of exposure to proton radiation, the changes observed in alloy 718 were the disappearance of the nickel and niobium rich grain boundaries precipitates and RIS of the major alloying elements (nickel to grain boundaries, and chromium and iron away from grain boundaries). On the other hand, in irradiated AISI 304L no differences were observed between intergranular and transgranular areas.

  4. Growth of cobalt ultra-thin films deposited on Pt(100) surfaces: An Auger electron spectroscopy study

    NASA Astrophysics Data System (ADS)

    Boeglin, C.; Carrière, B.; Deville, J. P.; Heckmann, O.; Leroux, C.; Panissod, P.

    1989-04-01

    To investigate the possibility of building Co/Pt modulated multilayers, attention has been paid to the early stages of interface formation between cobalt and platinum. The growth of cobalt layers less than 10 monolayers thick on Pt(100) surfaces has been studied by Auger electron spectroscopy. Growth kinetics obtained by AES show that two different models of interface formation can be possible: the Volmer-Weber case (cobalt islands) or an interdiffusion process between the two metals (similar to suicide formation). Looking at the fine structure of the low-energy platinum Auger transitions suggests that there is a strong interaction between cobalt and platinum as soon as the equivalent of a cobalt 2 monolayer coverage is deposited. This would favor the interdiffusion process model.

  5. Digital electronics for the Pierre Auger Observatory AMIGA muon counters

    NASA Astrophysics Data System (ADS)

    Wainberg, O.; Almela, A.; Platino, M.; Sanchez, F.; Suarez, F.; Lucero, A.; Videla, M.; Wundheiler, B.; Melo, D.; Hampel, M. R.; Etchegoyen, A.

    2014-04-01

    The ``Auger Muons and Infill for the Ground Array'' (AMIGA) project provides direct muon counting capacity to the Pierre Auger Observatory and extends its energy detection range down to 0.3 EeV. It currently consists of 61 detector pairs (a Cherenkov surface detector and a buried muon counter) distributed over a 23.5 km2 area on a 750 m triangular grid. Each counter relies on segmented scintillator modules storing a logical train of `0's and `1's on each scintillator segment at a given time slot. Muon counter data is sampled and stored at 320 MHz allowing both the detection of single photoelectrons and the implementation of an offline trigger designed to mitigate multi-pixel PMT crosstalk and dark rate undesired effects. Acquisition is carried out by the digital electronics built around a low power Cyclone III FPGA. This paper presents the digital electronics design, internal and external synchronization schemes, hardware tests, and first results from the Observatory.

  6. Auger electron spectroscopy for the determination of sex and age related Ca/P ratio at different bone sites

    SciTech Connect

    Balatsoukas, Ioannis; Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

    2010-10-15

    The Ca/P ratio of normal cortical and trabecular rat bone was measured by Auger electron spectroscopy (AES). Semiquantitative analysis was carried out using ratio techniques to draw conclusions on how age, sex and bone site affect the relative composition of calcium and phosphorus. Results show that Ca/P ratio is not sex dependent; quite the opposite, bone sites exhibit variations in elemental stoichiometry where femoral sections demonstrate higher Ca/P ratio than rear and front tibias. Age-related changes are more distinct for cortical bone in comparison with the trabecular bone. The latter's Ca/P ratio remains unaffected from all the parameters under study. This study confirms that AES is able to successfully quantify bone mineral main elements when certain critical points, related to the experimental conditions, are addressed effectively.

  7. Auger electron spectroscopy for the determination of sex and age related Ca/P ratio at different bone sites

    NASA Astrophysics Data System (ADS)

    Balatsoukas, Ioannis; Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

    2010-10-01

    The Ca/P ratio of normal cortical and trabecular rat bone was measured by Auger electron spectroscopy (AES). Semiquantitative analysis was carried out using ratio techniques to draw conclusions on how age, sex and bone site affect the relative composition of calcium and phosphorus. Results show that Ca/P ratio is not sex dependent; quite the opposite, bone sites exhibit variations in elemental stoichiometry where femoral sections demonstrate higher Ca/P ratio than rear and front tibias. Age-related changes are more distinct for cortical bone in comparison with the trabecular bone. The latter's Ca/P ratio remains unaffected from all the parameters under study. This study confirms that AES is able to successfully quantify bone mineral main elements when certain critical points, related to the experimental conditions, are addressed effectively.

  8. A new technique for Auger analysis of surface species subject to electron-induced desorption

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1973-01-01

    A method is presented to observe surface species subject to electron-induced desorption by Auger electron spectroscopy. The surface to be examined is moved under the electron beam at constant velocity, establishing a time independent condition and eliminating the time response of the electron spectrometer as a limiting factor. The dependence of the Auger signal on the surface velocity, incident electron current, beam diameter, and desorption cross section are analyzed. The method is illustrated by the Auger analysis of PTFE, in which the fluorine is removed by electron induced desorption.

  9. Multiple-Auger electron ejection after inner-shell ionization and excitation

    SciTech Connect

    Viefhaus, Jens

    2003-01-24

    Results on the Auger decay of core-ionized and core-exited Ar atoms above the Ar 2p threshold and at the Ar 2p3/2 {yields}3d resonance leading to double and triple ionization states are presented. Using a multiple time-of-flight analyzer arrangement for electron-electron coincidences, we directly observe for the first time a double Auger continuum following core electron ionization. Our results show clear evidence for continuously distributed Auger electron intensity over a 160 eV range of kinetic energies. This double Auger decay represents roughly 10 % of the normal single Auger channels. In the case of the resonant Auger decay we also observe a two-electron continuum of the same order of magnitude as in the non-resonant case which can be explained due to the existence of excited states of the doubly charged ion in the vicinity or just above the triple ionization threshold. In the latter case these states can further decay via emission of a low kinetic energy electron, which makes it possible to study the electron emission characteristics of the triple electron process. Both double- and triple-electron emission Auger processes will make it possible to study electron correlations undisturbed by the symmetry properties of the photoabsorption process.

  10. Is CO Carbon KVV Auger Electron Emission Affected by the Photoelectron?

    SciTech Connect

    Pruemper, G.; Fukuzawa, H.; Sakai, K.; Ueda, K.; Rolles, D.; Prince, K. C.; Harries, J. R.; Tamenori, Y.; Berrah, N.

    2008-12-05

    Angular distributions (ADs) of O{sup +} fragments from C 1s photoexcited CO detected in coincidence with carbon KVV Auger electrons emitted in the horizontal direction were measured at photon energies of 298, 305, 320, and 450 eV. At 450 eV, the ADs are polarization-independent and coincide with the molecular-frame Auger electron angular distribution. All measured ADs can be rationalized as a product of the same molecular-frame Auger electron angular distribution and the axial selectivity in the photoionization process. Thus the interaction between the photoelectron and the Auger electron for the normal Auger decay of CO can be neglected, and the two-step model is a good approximation.

  11. Auger spectroscopy of fracture surfaces of ceramics

    NASA Technical Reports Server (NTRS)

    Marcus, H. L.; Harris, J. M.; Szalkowski, F. J.

    1974-01-01

    Results of Auger electron spectroscopy (AES) studies of fracture surfaces in a series of ceramic materials, including Al2O3, MgO, and Si3N4, which were formed using different processing techniques. AES on the fractured surface of a lunar sample is also discussed. Scanning electron micrograph fractography is used to relate the surface chemistry to the failure mode. Combined argon ion sputtering and AES studies demonstrate the local variations in chemistry near the fracture surface. The problems associated with doing AES in insulators are also discussed, and the experimental techniques directed toward solving them are described.

  12. Angular correlation between photoelectrons and auger electrons from K-shell ionization of neon.

    PubMed

    Landers, A L; Robicheaux, F; Jahnke, T; Schöffler, M; Osipov, T; Titze, J; Lee, S Y; Adaniya, H; Hertlein, M; Ranitovic, P; Bocharova, I; Akoury, D; Bhandary, A; Weber, Th; Prior, M H; Cocke, C L; Dörner, R; Belkacem, A

    2009-06-01

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process. PMID:19658860

  13. Angular Correlation between Photoelectrons and Auger Electrons from K-Shell Ionization of Neon

    SciTech Connect

    Landers, A. L.; Robicheaux, F.; Bhandary, A.; Jahnke, T.; Schoeffler, M.; Titze, J.; Akoury, D.; Doerner, R.; Osipov, T.; Lee, S. Y.; Adaniya, H.; Hertlein, M.; Weber, Th.; Prior, M. H.; Belkacem, A.; Ranitovic, P.; Bocharova, I.; Cocke, C. L.

    2009-06-05

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  14. Characterization of oxide layers on amorphous Zr-based alloys by Auger electron spectroscopy with sputter depth profiling

    NASA Astrophysics Data System (ADS)

    Baunack, S.; Mudali, U. Kamachi; Gebert, A.

    2005-09-01

    Amorphous Zr-Cu-Ni-Al-[Ti, Nb] ribbons prepared by melt spinning under argon atmosphere were subjected to electrochemical investigations. Passive films developed at potentiostatic anodic polarization in sulphuric acid solution were investigated by Auger electron spectroscopy (AES) and sputter depth profiling. Changes in the shape of the Auger peaks have been analyzed by factor analysis of the spectra obtained during depth profiling. Pronounced changes in shape and position occur for the Zr, Al, and Ti Auger transitions, but not for Cu and Ni. At least three different peak shapes for O(KVV) were found and attributed to different oxygen binding states. The alloy composition has no significant effect on the thickness and composition of the oxide layer. In multi-element alloys preferential sputtering is a common phenomenon. In the steady state of sputtering, a significant depletion in Cu is found. At the oxide/metal interface, a distinct enrichment of copper is found for all alloys and treatments. The degree of this Cu enrichment depends on the pretreatment. It is higher for the electrochemically-passivated samples than for samples with oxide layers grown during melt spinning.

  15. Change of Auger-electron emission from Ni-Pd alloys under magnetic phase transition

    NASA Astrophysics Data System (ADS)

    Elovikov, S. S.; Zykova, E. Y.; Gvozdover, R. S.; Colligon, J. S.; Yurasova, V. E.

    2006-04-01

    The change of Auger-electron emission from polycrystals of disordered ferromagnetic NiPd 3 and Ni 3 Pd alloys, under ferro- to paramagnetic transition, has been studied experimentally. It has been shown that the intensity of the Auger-lines, which are formed because of transition of valent zone 3d 3/2 and 3d 5/2 electrons, has local maxima near the Curie point T C for the alloys. Thus, the sensitivity of Auger-electron emission to a magnetic state of the alloy has been established.

  16. Auger electron intensity variations in oxygen-exposed large grain polycrystalline silver

    NASA Technical Reports Server (NTRS)

    Lee, W. S.; Outlaw, R. A.; Hoflund, G. B.; Davidson, M. R.

    1989-01-01

    Auger electron spectroscopic studies of the grains in oxygen-charged polycrystal-line silver show significant intensity variations as a function of crystallographic orientation. These intensity variations were observed by studies of the Auger images and line scans of the different grains (randomly selected) for each silver transition energy. The results can be attributed to the diffraction of the ejected Auger electrons and interpreted by corresponding changes in the electron mean-free path for inelastic scattering and by oxygen atom accumulation in the subsurface. The subsurface (second layer) octahedral sites increased in size because of surface relaxation and serve as a stable reservoir for the dissolved oxygen.

  17. May Auger electron spectroscopy provide surface structural information?

    NASA Astrophysics Data System (ADS)

    Alonso, M.; Soria, F.

    1986-12-01

    Quantitative analysis of Auger electron spectroscopy peak energies, lineshapes and heights allows to determine the chemical composition of the surface layer, and in binary (111) semiconductors even the composition of the outermost surface bilayer, if the composition of a standard surface is known. Surface structural information can also be obtained by the interaction of these surfaces with some gases used as markers, when the gas absorption proceeds by an over/underlayer mechanism, as it happens in the initial stages of the interaction of oxygen with differently prepared GaAs(111) surfaces. Thus, we have been able to confirm the structure of the (111) 2 × 2 Ga surface, and to determine the oxygen absorption sites and occupation sequence, by comparison of the experimental intensities with calculations which model the surface structure and absorption sites. This formalism has also been applied to ( overline1overline1overline1) 1 × 1 facetted surfaces, where very different absorption behaviour is seen for surfaces prepared at different ion energies, but annealed at the same temperature.

  18. NHEXAS PHASE I REGION 5 STUDY--STANDARD OPERATING PROCEDURE FOR METTLER AE163 AND AE240 ELECTRONIC BALANCE (NHX/SOP-160-008)

    EPA Science Inventory

    This procedure describes the process of calibrating the Mettler AE 163 and AE 240 electronic, dual range analytical balances each having an enclosed weighing pan. Weight ranges for the AE 163 are 0-30 g (0.01 mg readability) and 0-160 g (0.1 mg readability). Weight ranges for the...

  19. Oxidation study by Auger electron spectroscopy and electron energy-loss spectroscopy of GaSb(001) surfaces grown by molecular-beam epitaxy

    SciTech Connect

    Raisin, C.; Da Silva, F.W.O.; Lassabatere, L. , Place Eugene Bataillon, 34095 Montpellier-Cedex 5, France )

    1990-01-01

    GaSb (001) surfaces were prepared by molecular-beam epitaxy. Auger electron spectroscopy (AES) and electron energy-loss spectroscopy (EELS) are reported for clean surfaces exposed to oxygen, and during the process the ionization gauge of the vacuum system is turned on. Successive stages of chemisorption can be distinguished. For oxygen coverage up to 0.5 monolayer, the surface states are saturated by bonding of the oxygen with Ga and Sb atoms. Sb atoms desorb causing significant Sb depletion in the first layer. Larger exposures further increase the coverage and induce, in the EELS spectra, losses related to O(2{ital p}) and O(2{ital s}) atomic states and new plasmon excitations. In the AES spectra the shift of Auger emission lines which are characteristic of Sb and Ga oxide forms appear; at coverages of about one monolayer back bonds break forming Sb{sub 2}O{sub 3} and Ga{sub 2}O{sub 3}. Further exposures to oxygen result in thicker oxide layers of Ga and Sb.

  20. Auger electron spectroscopy, secondary ion mass spectroscopy and optical characterization of a-C-H and BN films

    NASA Technical Reports Server (NTRS)

    Pouch, J. J.; Alterovitz, S. A.; Warner, J. D.

    1986-01-01

    The amorphous dielectrics a-C:H and BN were deposited on III-V semiconductors. Optical band gaps as high as 3 eV were measured for a-C:H generated by C4H10 plasmas; a comparison was made with bad gaps obtained from films prepared by CH4 glow discharges. The ion beam deposited BN films exhibited amorphous behavior with band gaps on the order of 5 eV. Film compositions were studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The optical properties were characterized by ellipsometry, UV/VIS absorption, and IR reflection and transmission. Etching rates of a-C:H subjected to O2 dicharges were determined.

  1. Molecular-Frame Angular Distributions of Resonant CO:C(1s) Auger Electrons

    SciTech Connect

    Rolles, D.; Pesic, Z. D.; Dumitriu, I.; Pruemper, G.; Fukuzawa, H.; Liu, X.-J.; Ueda, K.; Fink, R. F.; Grum-Grzhimailo, A. N.; Berrah, N.

    2008-12-31

    The molecular-frame angular distributions of resonantly excited CO:C(1s){yields}{pi}* Auger electrons were determined using angle-resolved electron-ion coincidence spectroscopy in combination with a novel transformation procedure. Our new methodology yields full three-dimensional electron angular distributions with high energy resolution from the measurement of electrons at only two angles. The experimentally determined distributions are well reproduced by calculations performed in a simple one-center approximation, allowing an unambiguous identification of several overlapping Auger lines.

  2. Selective detection of angular-momentum-polarized Auger electrons by atomic stereography.

    PubMed

    Matsui, Fumihiko; Fujita, Masayoshi; Ohta, Takuya; Maejima, Naoyuki; Matsui, Hirosuke; Nishikawa, Hiroaki; Matsushita, Tomohiro; Daimon, Hiroshi

    2015-01-01

    When a core level is excited by circularly polarized light, the angular momentum of light is transferred to the emitted photoelectron, which can be confirmed by the parallax shift of the forward focusing peak (FFP) direction in a stereograph of atomic arrangement. No angular momentum has been believed to be transferred to normal Auger electrons resulting from the decay process filling core hole after photoelectron ejection. We succeeded in detecting a non-negligible circular dichroism contrast in a normal Auger electron diffraction from a nonmagnetic Cu(001) surface far off from the absorption threshold. Moreover, we detected angular-momentum-polarized Cu L(3)M(4,5)M(4,5) Auger electrons at the L(3) absorption threshold, where the excited core electron is trapped at the conduction band. From the kinetic energy dependence of the Auger electron FFP parallax shift, we found that the angular momentum is transferred to the Auger electron most effectively in the case of the (1)S(0) two-hole creation. PMID:25615477

  3. A high voltage power supply for the AE-C and D low energy electron experiment

    NASA Technical Reports Server (NTRS)

    Gillis, J. A.

    1974-01-01

    A description is given of the electrical and mechanical design and operation of high voltage power supplies for space flight use. The supply was used to generate the spiraltron high voltage for low energy electron experiment on AE-C and D. Two versions of the supply were designed and built; one design is referred to as the low power version (AE-C) and the other as the high power version (AE-D). Performance is discussed under all operating conditions.

  4. Angular Correlation of Electrons Emitted by Double Auger Decay of K-Shell Ionized Neon

    NASA Astrophysics Data System (ADS)

    Jones, Matthew Philip

    2011-12-01

    We have investigated in detail the 4-body continuum state produced when core-ionized neon undergoes Double-Auger (DA) decay, using COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS ). We conducted the experiment at the Lawrence Berkeley National Laboratory's Advanced Light Source (LBNL-ALS) beamline 11.0.2. The synchrotron operated in 2-bunch mode and outputted an elliptically polarized, pulsed photon beam (hn=872.9eV), sufficient to K-shell ionize neon just above threshold. Our analysis supports research showing that Auger electrons tend to share energy asymmetrically. We qualitatively compared this result to Photo-Double Ionization (PDI) of helium. Further, we confirm research that shows how Auger electrons that share energy symmetrically can be modeled by the elastic-like knock-out process plus Post-Collision Interaction ( PCI) effects. New observations include the angular correlation between the photo-electron and each respective Auger electron, for specific ranges of energy sharing. We identify a broad feature in the asymmetric case that shows a level of interaction between electrons that until recently, has disagreed with theory. Additionally, we consider the angular correlation between the photo-electron and the momentum sum of the Auger electrons. We observe that the angular correlation between this sum and the photo-electron in the highly asymmetric case is nearly identical to the correlation between just the fast-Auger and the photo-electron - as expected. In the case of symmetric energy sharing, the sum momentum vector appears to be isotropic, particularly for small angles of interaction. Finally, we acknowledge two novel methods of calibration. The first, uses well known line-energies to calibrate the spectrometer. These lines correspond to the decay channels of core-excited neon, Ne(1 s-13p). The second, describes a method to statistically weight list-mode data in order to calibrate it to well known physical features (e.g., isotropic distributions).

  5. Structure of the initial stages of oxidation of A1{111} surfaces from low-energy-electron diffraction and Auger electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Soria, F.; Martínez, V.; Muñoz, M. C.; Sacedón, J. L.

    1981-12-01

    The structure of the initial stages of oxidation of A1{111} surfaces has been determined by low-energy-electron diffraction (LEED) and Auger-electron-spectroscopy (AES) measurements. The oxidation process can be described by a four-stage mechanism depending on the oxygen exposure: 0-30 L; 30-100 L; 100-200 L; and 200 onwards. At the end of the first stage, the transition density of states (TDOS) obtained by self-deconvolution of the A1{111} -25-L RT O2-exposure L2,3VV AES spectra and comparison with theoretical calculations of the DOS for this coverage show that the oxygen atoms occupy the fcc threefold hollows in an underlayer configuration, with an interplanar distance d12=0.0-0.5 Å. At 100-L RT O2 exposure, AES and LEED indicate the formation of a complete A1{111} 1 × 1-O overlayer structure with the oxygen atoms occupying the fcc threefold hollows at d12=0.73+/-0.05 Å. At 150 L, d12=0.80+/-0.03 Å for the same A1{111} 1 × 1-O structure. These LEED values solve the discrepancy with the surface-extended x-ray-absorption fine-structure measurements, and suggest the need for a revision of interplanar distances previously determined by LEED for oxygen-metal structures.

  6. Time of flight spectrometer for background-free positron annihilation induced Auger electron spectroscopy.

    PubMed

    Mukherjee, S; Shastry, K; Anto, C V; Joglekar, P V; Nadesalingam, M P; Xie, S; Jiang, N; Weiss, A H

    2016-03-01

    We describe a novel spectrometer designed for positron annihilation induced Auger electron spectroscopy employing a time-of-flight spectrometer. The spectrometer's new configuration enables us to implant monoenergetic positrons with kinetic energies as low as 1.5 eV on the sample while simultaneously allowing for the detection of electrons emitted from the sample surface at kinetic energies ranging from ∼500 eV to 0 eV. The spectrometer's unique characteristics made it possible to perform (a) first experiments demonstrating the direct transition of a positron from an unbound scattering state to a bound surface state and (b) the first experiments demonstrating that Auger electron spectra can be obtained down to 0 eV without the beam induced secondary electron background obscuring the low energy part of the spectra. Data are presented which show alternative means of estimating positron surface state binding energy and background-free Auger spectra. PMID:27036826

  7. Time of flight spectrometer for background-free positron annihilation induced Auger electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Shastry, K.; Anto, C. V.; Joglekar, P. V.; Nadesalingam, M. P.; Xie, S.; Jiang, N.; Weiss, A. H.

    2016-03-01

    We describe a novel spectrometer designed for positron annihilation induced Auger electron spectroscopy employing a time-of-flight spectrometer. The spectrometer's new configuration enables us to implant monoenergetic positrons with kinetic energies as low as 1.5 eV on the sample while simultaneously allowing for the detection of electrons emitted from the sample surface at kinetic energies ranging from ˜500 eV to 0 eV. The spectrometer's unique characteristics made it possible to perform (a) first experiments demonstrating the direct transition of a positron from an unbound scattering state to a bound surface state and (b) the first experiments demonstrating that Auger electron spectra can be obtained down to 0 eV without the beam induced secondary electron background obscuring the low energy part of the spectra. Data are presented which show alternative means of estimating positron surface state binding energy and background-free Auger spectra.

  8. Angle-resolved Auger electron spectra induced by neon ion impact on aluminum

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.; Aron, P. R.

    1986-01-01

    Auger electron emission from aluminum bombarded with 1 to 5 keV neon ions was studied by angle-resolved electron spectroscopy. The position and shape of the spectral features depended on the incident ion energy, angle of ion incidence, and electron take-off angle with respect to the aluminum surface. These spectral dependencies were interpreted in terms of the Doppler shift given to the Auger electron velocity by the excited atom ejected into the vacuum. For oblique ion incidence it is concluded that a flux of high energy atoms are ejected in a direction close to the projection of the ion beam on the target surface. In addition, a new spectral feature was found and identified as due to Auger emission from excited neon in the aluminum matrix.

  9. Evaluating {sup 99m}Tc Auger electrons for targeted tumor radiotherapy by computational methods

    SciTech Connect

    Tavares, Adriana Alexandre S.; Tavares, Joao Manuel R. S.

    2010-07-15

    Purpose: Technetium-99m ({sup 99m}Tc) has been widely used as an imaging agent but only recently has been considered for therapeutic applications. This study aims to analyze the potential use of {sup 99m}Tc Auger electrons for targeted tumor radiotherapy by evaluating the DNA damage and its probability of correct repair and by studying the cellular kinetics, following {sup 99m}Tc Auger electron irradiation in comparison to iodine-131 ({sup 131}I) beta minus particles and astatine-211 ({sup 211}At) alpha particle irradiation. Methods: Computational models were used to estimate the yield of DNA damage (fast Monte Carlo damage algorithm), the probability of correct repair (Monte Carlo excision repair algorithm), and cell kinetic effects (virtual cell radiobiology algorithm) after irradiation with the selected particles. Results: The results obtained with the algorithms used suggested that {sup 99m}Tc CKMMX (all M-shell Coster-Kroning--CK--and super-CK transitions) electrons and Auger MXY (all M-shell Auger transitions) have a therapeutic potential comparable to high linear energy transfer {sup 211}At alpha particles and higher than {sup 131}I beta minus particles. All the other {sup 99m}Tc electrons had a therapeutic potential similar to {sup 131}I beta minus particles. Conclusions: {sup 99m}Tc CKMMX electrons and Auger MXY presented a higher probability to induce apoptosis than {sup 131}I beta minus particles and a probability similar to {sup 211}At alpha particles. Based on the results here, {sup 99m}Tc CKMMX electrons and Auger MXY are useful electrons for targeted tumor radiotherapy.

  10. Differential auger spectrometry

    DOEpatents

    Strongin, Myron; Varma, Matesh Narayan; Anne, Joshi

    1976-06-22

    Differential Auger spectroscopy method for increasing the sensitivity of micro-Auger spectroanalysis of the surfaces of dilute alloys, by alternately periodically switching an electron beam back and forth between an impurity free reference sample and a test sample containing a trace impurity. The Auger electrons from the samples produce representative Auger spectrum signals which cancel to produce an Auger test sample signal corresponding to the amount of the impurity in the test samples.

  11. Validation of 64Cu-ATSM damaging DNA via high-LET Auger electron emission.

    PubMed

    McMillan, Dayton D; Maeda, Junko; Bell, Justin J; Genet, Matthew D; Phoonswadi, Garrett; Mann, Kelly A; Kraft, Susan L; Kitamura, Hisashi; Fujimori, Akira; Yoshii, Yukie; Furukawa, Takako; Fujibayashi, Yasuhisa; Kato, Takamitsu A

    2015-09-01

    Radioactive copper (II) (diacetyl-bis N4-methylthiosemicarbazone) (Cu-ATSM) isotopes were originally developed for the imaging of hypoxia in tumors. Because the decay of a (64)Cu atom is emitting not only positrons but also Auger electrons, this radionuclide has great potential as a theranostic agent. However, the success of (64)Cu-ATSM internal radiation therapy would depend on the contribution of Auger electrons to tumor cell killing. Therefore, we designed a cell culture system to define the contributions to cell death from Auger electrons to support or refute our hypothesis that the majority of cell death from (64)Cu-ATSM is a result of high-LET Auger electrons and not positrons or other low-LET radiation. Chinese hamster ovary (CHO) wild type and DNA repair-deficient xrs5 cells were exposed to (64)Cu-ATSM during hypoxic conditions. Surviving fractions were compared with those surviving gamma-radiation, low-LET hadron radiation, and high-LET heavy ion exposure. The ratio of the D(10) values (doses required to achieve 10% cell survival) between CHO wild type and xrs5 cells suggested that (64)Cu-ATSM toxicity is similar to that of high-LET Carbon ion radiation (70 keV/μm). γH2AX foci assays confirmed DNA double-strand breaks and cluster damage by high-LET Auger electrons from (64)Cu decay, and complex types of chromosomal aberrations typical of high-LET radiation were observed after (64)Cu-ATSM exposure. The majority of cell death was caused by high-LET radiation. This work provides strong evidence that (64)Cu-ATSM damages DNA via high-LET Auger electrons, supporting further study and consideration of (64)Cu-ATSM as a cancer treatment modality for hypoxic tumors. PMID:26251463

  12. Validation of 64Cu-ATSM damaging DNA via high-LET Auger electron emission

    PubMed Central

    McMillan, Dayton D.; Maeda, Junko; Bell, Justin J.; Genet, Matthew D.; Phoonswadi, Garrett; Mann, Kelly A.; Kraft, Susan L.; Kitamura, Hisashi; Fujimori, Akira; Yoshii, Yukie; Furukawa, Takako; Fujibayashi, Yasuhisa; Kato, Takamitsu A.

    2015-01-01

    Radioactive copper (II) (diacetyl-bis N4-methylthiosemicarbazone) (Cu-ATSM) isotopes were originally developed for the imaging of hypoxia in tumors. Because the decay of a 64Cu atom is emitting not only positrons but also Auger electrons, this radionuclide has great potential as a theranostic agent. However, the success of 64Cu-ATSM internal radiation therapy would depend on the contribution of Auger electrons to tumor cell killing. Therefore, we designed a cell culture system to define the contributions to cell death from Auger electrons to support or refute our hypothesis that the majority of cell death from 64Cu-ATSM is a result of high-LET Auger electrons and not positrons or other low-LET radiation. Chinese hamster ovary (CHO) wild type and DNA repair–deficient xrs5 cells were exposed to 64Cu-ATSM during hypoxic conditions. Surviving fractions were compared with those surviving gamma-radiation, low-LET hadron radiation, and high-LET heavy ion exposure. The ratio of the D10 values (doses required to achieve 10% cell survival) between CHO wild type and xrs5 cells suggested that 64Cu-ATSM toxicity is similar to that of high-LET Carbon ion radiation (70 keV/μm). γH2AX foci assays confirmed DNA double-strand breaks and cluster damage by high-LET Auger electrons from 64Cu decay, and complex types of chromosomal aberrations typical of high-LET radiation were observed after 64Cu-ATSM exposure. The majority of cell death was caused by high-LET radiation. This work provides strong evidence that 64Cu-ATSM damages DNA via high-LET Auger electrons, supporting further study and consideration of 64Cu-ATSM as a cancer treatment modality for hypoxic tumors. PMID:26251463

  13. Novel time-of-flight spectrometer for the analysis of positron annihilation induced Auger electrons

    SciTech Connect

    Hugenschmidt, Christoph; Legl, Stefan

    2006-10-15

    Positron annihilation induced Auger-electron spectroscopy (PAES) has several advantages over conventional Auger-electron spectroscopy such as extremely high surface sensitivity and outstanding signal-to-noise ratio at the Auger-transition energy. In order to benefit from these prominent features a low-energy positron beam of high intensity is required for surface sensitive PAES studies. In addition, an electron energy analyzer is required, which efficiently detects the Auger electrons with acceptable energy resolution. For this reason a novel time-of-flight (TOF) spectrometer has been developed at the intense positron source NEPOMUC that allows PAES studies within short measurement time. This TOF-PAES setup combines a trochoidal filter and a flight tube in a Faraday cage in order to achieve an improved energy resolution of about 1 eV at high electron energies up to E{approx_equal}1000 eV. The electron flight time is the time between the annihilation radiation at the sample and when the electron hits a microchannel plate detector at the end of the flight tube.

  14. A detailed Auger electron spectroscopy study of the first stages of the growth of C60 thin films

    NASA Astrophysics Data System (ADS)

    Vidal, R. A.; Ferrón, J.

    2015-11-01

    In this work we take advantage of the large sensitivity and in-depth resolution of Auger electron spectroscopy (AES) to study in a detailed way the growth of C60 over different substrates, namely Cu(1 1 1), Si(1 0 0) and graphene. The ability of AES, as compared to more local probes like STM or AFM, to follow the process in a dynamic way, allows us to study the growth of C60 below and over one ML, including the change of C60 over either Si or Cu to the growth of C60 over a C60 film. We found that the growth always proceeds layer by layer. This result shows that differences in diffusion barriers are not as important as one may think following the idea of diffusion by a jumping mechanism. We propose that the sticking coefficient, governed by the adsorption energy, is responsible for the differences observed between Cu and Si. Our results also point to a different charge transfer among fullerene molecules and these surfaces. The same result is suggested in the case of C60 over graphene, but in this case our conclusion comes from the variable temperature experiments.

  15. PHOTOELECTRON AND AUGER ELECTRON ASYMMETRIES: ALIGNMENT OF Xe{sup +}({sup 2}D{sub 5/2}) BY PHOTOIONIZATION

    SciTech Connect

    Southworth, S. H.; Kobrin, P. H.; Truesdale, C. M.; Lindle, D.; Owaki, S.; Shirley, D. A.

    1980-12-01

    Angular distributions of photoelectrons from the Xe 4d subshell, and N{sub 4,5}oo Auger electrons, have been measured using synchrotron radiation. The 4d asymmetry parameter exhibits strong oscillations with energy, in agreement with several theoretical calculations. The Auger electrons show large asymmetries due to alignment of Xe{sup +} by photoionization.

  16. Observation of suppressed Auger mechanism in type-I quantum well structures with delocalized electron-hole wavefunctions

    SciTech Connect

    Hassani Nia, Iman; Fathipour, Vala; Mohseni, Hooman

    2015-08-15

    We report the first observation of non-threshold Auger mechanism for a quantum well structure with Type-I band alignment. Excitation-dependent photoluminescence measurements were used to extract the Auger recombination coefficients from 77 K up to room temperature. The results verify the role of interface mediated momentum exchange as well as suppression of Auger recombination for delocalized electron-hole wavefunctions.

  17. Communication: Formation of slow electrons in the Auger decay of core-ionized water molecules

    NASA Astrophysics Data System (ADS)

    Hikosaka, Y.; Yamamoto, K.; Nakano, M.; Odagiri, T.; Soejima, K.; Suzuki, I. H.; Lablanquie, P.; Penent, F.; Ito, K.

    2012-11-01

    Double Auger decay of O1s-1 and its satellite states in H2O has been studied with a multi-electron coincidence method, and a process leading to autoionizing O* fragments has been revealed. The breaking of the two O-H bonds producing the autoionizing O* fragments occurs for highly excited H2O2+ populated by the initial Auger decay. The O* fragments are more favorably produced in the decay from the satellite states, resulting from the larger population of highly excited H2O2+ states inheriting the valence excitation in the initial state.

  18. Communication: Formation of slow electrons in the Auger decay of core-ionized water molecules.

    PubMed

    Hikosaka, Y; Yamamoto, K; Nakano, M; Odagiri, T; Soejima, K; Suzuki, I H; Lablanquie, P; Penent, F; Ito, K

    2012-11-21

    Double Auger decay of O1s(-1) and its satellite states in H(2)O has been studied with a multi-electron coincidence method, and a process leading to autoionizing O* fragments has been revealed. The breaking of the two O-H bonds producing the autoionizing O* fragments occurs for highly excited H(2)O(2+) populated by the initial Auger decay. The O* fragments are more favorably produced in the decay from the satellite states, resulting from the larger population of highly excited H(2)O(2+) states inheriting the valence excitation in the initial state. PMID:23181286

  19. Production of Ne Auger electrons by Ne/+/ bombardment of Mg and Al surfaces

    NASA Technical Reports Server (NTRS)

    Ferrante, J.; Pepper, S. V.

    1976-01-01

    A description is given of experiments which provide evidence for the production of an inner shell vacancy in the Ne by the asymmetric Ne-Mg and Ne-Al collision. In addition, autoionization states of neutral Ne have been observed. These states are to be distinguished from the more usual case in Auger electron spectroscopy of de-excitation of an ion with a core vacancy. The experiments involved the bombardment of Mg and Al surfaces with Ne(+) ions. A LEED-Auger system equipped with an ion gun and a four-grid retarding potential analyzer operated in the usual dN(E)/dE mode was used.

  20. A new technique for Auger analysis of surface species subject to electron-induced desorption.

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1973-01-01

    A method is presented to observe surface species subject to electron-induced desorption by Auger electron spectroscopy. The surface to be examined is moved under the electron beam at constant velocity, establishing a time-independent condition and eliminating the time response of the electron spectrometer as a limiting factor. The dependence of the Auger signal on the sample velocity, incident electron current, beam diameter, and desorption cross section is analyzed. It is shown that it is advantageous to analyze the moving sample with a high beam current, in contrast to the usual practice of using a low beam current to minimize desorption from a stationary sample. The method is illustrated by the analysis of a friction transfer film of PTFE, in which the fluorine is removed by electron-induced desorption. The method is relevant to surface studies in the field of lubrication and catalysis.

  1. Angular distribution of molecular K-shell Auger electrons: Spectroscopy of photoabsorption anisotropy

    SciTech Connect

    Dill, D.; Swanson, J.R.; Wallace, S.; Dehmer, J.L.

    1980-10-27

    The angular distribution of Auger electrons emitted in the decay of molecular K-shell vacancies created by photoabsorption is predicted to be a direct probe of the anisotropy of molecular photoabsorption. The sigma..--> pi.. discrete absorption of the sigma..-->..sigma f-wave shape resonance in N/sub 2/ and CO are given as examples.

  2. Fluorine Auger-electron production in collisions of H+ and Li2+ with fluorocarbon targets

    NASA Astrophysics Data System (ADS)

    Shinpaugh, J. L.; Toburen, L. H.; Justiniano, E. L. B.

    1999-12-01

    Relative and absolute cross sections are presented for fluorine KLL Auger-electron production in collisions of 2.0-MeV H+ and 0.5-MeV/amu Li2+ with various fluorocarbon targets. Auger yields were measured for molecular targets of CH3F, CH2F2, C2H2F2, CHF3, CF4, C2F6, and C4F8. The fluorine Auger cross sections for these collision systems were found to be independent of the chemical environment, i.e., the atomic cross sections were found to obey additivity for these molecules. This is in contrast to recently reported fluorine K-shell ionization cross sections found for He+ impact on fluorocarbon targets, where the atomic cross sections were found to differ by up to a factor of 3.

  3. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    NASA Astrophysics Data System (ADS)

    Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji

    2015-11-01

    A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si3N4/SiO2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  4. Auger electron spectroscopy of super-doped Si:Mn thin films

    NASA Astrophysics Data System (ADS)

    Abe, S.; Nakasima, Y.; Okubo, S.; Nakayama, H.; Nishino, T.; Yanagi, H.; Ohta, H.; Iida, S.

    1999-04-01

    Thin films of Si heavily doped with Mn impurities at nonequilibrium doping levels have been successfully prepared by Laser-Ablation MBE. The electronic structure of Mn-doped Si thin films have been investigated by Auger Valence Electron Spectroscopy (AVES). The peak positions of Mn[3p,V,V] (V=3d) Auger spectra of Si:Mn thin films were located at the higher energy region than those of pure Mn and Mn 5Si 3 compound. For the Si:Mn thin film grown on SiO 2/Si(001) substrate, the new Auger peak was observed around 50 eV. The changes of the line shape were observed in Mn[L,M,M] (L=2s,2p; M=3s,3p,3d) Auger spectra of Si:Mn thin films compared with those of pure Mn and Mn 5Si 3 compounds. In the Mn[2s,M,V] (M=3s,3p,V=3d) spectra for Si:Mn thin films, the new peaks were appeared around 700 eV. These new peaks were considered to arise from the new split of the 3d electron states due to the formation of the Mn-Si bonds in Si:Mn thin films.

  5. Surface compositions of atomic layer deposited Zn{sub 1−x}Mg{sub x}O thin films studied using Auger electron spectroscopy

    SciTech Connect

    Xie, Ting; Romero, Danilo; Gomez, Romel D.

    2015-09-15

    In this paper, the authors present Auger electron spectroscopy (AES) studies of Zn{sub 1−x}Mg{sub x}O (ZMO) films grown via interrupted atomic-layer deposition (ALD) techniques. The ZMO films were fabricated by alternating ALD deposition of ZnO and MgO layers up to 1000 cycles. Zn{sub 1−x}Mg{sub x}O films with progressively decreasing Mg/Zn ratios (Mg/Zn = 1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/9, and 2/8, 3/12, 4/16, and 5/20) were fabricated for this study. The AES results exhibit an abrupt drop of Mg composition on the ZMO surface when the Mg/Zn < 1/3. Additionally, the surface composition ratios of O to Mg, O to Zn, and Mg to Zn were estimated with known Auger sensitivity factors. The results indicate that Mg ions diffuse into the bulk, forming Zn{sub 1−x}Mg{sub x}O alloys.

  6. ANALYSIS OF PASSIVATED SURFACES FOR MASS SPECTROMETER INLET SYSTEMS BY AUGER ELECTRON AND X-RAY PHOTOELECTRON SPECTROSCOPY

    SciTech Connect

    Ajo, H.; Clark, E.

    2010-09-01

    Stainless steel coupons approximately 0.5' in diameter and 0.125' thick were passivated with five different surface treatments and an untreated coupon was left as a control. These surface treatments are being explored for use in tritium storage containers. These coupons were made to allow surface analysis of the surface treatments using well-know surface analysis techniques. Depth profiles using Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were performed on these coupons to characterize the surface and near surface regions. Scanning electron microscope (SEM) images were collected as well. All of the surface treatments studied here appear to change the surface morphology dramatically, as evidenced by lack of tool marks on the treated samples. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7-0.9 nm thick) as well as the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E's silicon coating appears to be on the order of 200 nm thick.

  7. Angular distribution of Auger electrons due to 3d-shell ionization of krypton

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1977-01-01

    Cross sections for electron impact ionization of krypton due to ejection of a 3rd shell electron have been calculated using screened hydrogenic and Hartree-Slater wave functions for target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3rd electrons, is widely different in the two approximations. The angular distribution due to Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.

  8. Angular distribution of Auger electrons due to 3d-shell impact ionization of krypton

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1977-01-01

    Cross sections for electron impact ionization of krypton due to ejection of a 3d-shell electron have been calculated using screened hydrogenic and Hartree-Slater wavefunctions for the target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3d electrons, are widely different in the two approximations. The angular distribution due to the Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.

  9. Microdosimetry of the Auger electron emitting 123I radionuclide using Geant4-DNA simulations

    NASA Astrophysics Data System (ADS)

    Fourie, H.; Newman, R. T.; Slabbert, J. P.

    2015-04-01

    Microdosimetric calculations of the Auger electron emitter 123I were done in liquid water spheres using the Geant4 toolkit. The electron emission spectrum of 123I produced by Geant4 is presented. Energy deposition and corresponding S-values were calculated to investigate the influence of the sub-cellular localization of the Auger emitter. It was found that S-values calculated by the Geant4 toolkit are generally lower than the values calculated by other Monte Carlo codes for the 123I radionuclide. The differences in the compared S-values are mainly due to the different particle emission spectra employed by the respective computational codes and emphasizes the influence of the spectra on dosimetry calculations.

  10. Microdosimetry of the Auger electron emitting 123I radionuclide using Geant4-DNA simulations.

    PubMed

    Fourie, H; Newman, R T; Slabbert, J P

    2015-04-21

    Microdosimetric calculations of the Auger electron emitter (123)I were done in liquid water spheres using the Geant4 toolkit. The electron emission spectrum of (123)I produced by Geant4 is presented. Energy deposition and corresponding S-values were calculated to investigate the influence of the sub-cellular localization of the Auger emitter. It was found that S-values calculated by the Geant4 toolkit are generally lower than the values calculated by other Monte Carlo codes for the (123)I radionuclide. The differences in the compared S-values are mainly due to the different particle emission spectra employed by the respective computational codes and emphasizes the influence of the spectra on dosimetry calculations. PMID:25825914

  11. Receptor-DNA binding to target auger electrons for cancer therapy. Final report, August 1, 1993--January 31, 1997

    SciTech Connect

    DeSombre, E.R.

    1997-05-01

    The goal of this program was to investigate the principle of receptor-DNA binding as a means to target Auger electron radiation for cancer therapy, and thereby to evaluate the potential of non-covalent, high-affinity, Auger electron-emitting ligands binding to a DNA associated molecule, or DNA itself, for cancer therapy. These studies were intended to assess the ability of Auger-emitting estrogens to kill estrogen receptor-positive tumor cells, determine the mean lethal dose, and determine whether they could be effective in vitro and in vivo.

  12. Impact of IUdR on Rat 9L glioma cell survival for 25-35 keV photon-activated auger electron therapy.

    PubMed

    Alvarez, Diane; Hogstrom, Kenneth R; Brown, Thomas A D; Ii, Kenneth L Matthews; Dugas, Joseph P; Ham, Kyungmin; Varnes, Marie E

    2014-12-01

    The goal of the current study was to measure the energy dependence of survival of rat 9L glioma cells labeled with iododeoxyuridine (IUdR) that underwent photon-activated Auger electron therapy using 25-35 keV monochromatic X rays, i.e., above and below the K-edge energy of iodine. Rat 9L glioma cells were selected because of their radioresistance, ability to be implanted for future in vivo studies and analogy to radioresistant human gliomas. Survival curves were measured for a 4 MV X-ray beam and synchrotron produced monochromatic 35, 30 and 25 keV X-ray beams. IUdR was incorporated into the DNA at levels of 0, 9 and 18% thymidine replacement for 4 MV and 35 keV and 0 and 18% thymidine replacement for 30 and 25 keV. For 10 combinations of beam energy and thymidine replacement, 62 data sets (3-13 per combination) provided 776 data points (47-148 per combination). Survival versus dose data taken for the same combination, but on different days, were merged by including the zero-dose points in the nonlinear, chi-squared data fitting using the linear-quadratic model and letting the best estimate to the zero-dose plating efficiency for each of the different days be a fitting parameter. When comparing two survival curves, the ratio of doses resulting in 10% survival gave sensitization enhancement ratios (SER10) from which contributions due to linear energy transfer (LET) (SER10,LET), IUdR radiosensitization (SER10,RS), the Auger effect (SER10,AE) and the total of all effects (SER10,T) were determined. At 4 MV and 35, 30 and 25 keV, SER10,LET values were 1.00, 1.08 ± 0.03, 1.22 ± 0.02 and 1.37 ± 0.02, respectively. At 4 MV SER10,RS values for 9 and 18% IUdR were 1.28 ± 0.02 and 1.40 ± 0.02, respectively. Assuming LET effects were independent of percentage IUdR and radiosensitization effects were independent of energy, SER10,AE values for 18% IUdR at 35, 30 and 25 keV were 1.35 ± 0.05, 1.06 ± 0.03 and 0.98 ± 0.03, respectively. The value for 9% IUdR at 35 keV was 1

  13. Auger analysis of films formed on metals in sliding contact with halogenated polymers

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1974-01-01

    The use of Auger electron spectroscopy (AES) to search for transferred polymer must contend with the fact that there has been no published work on Auger analysis of polymers. Since this is a new area for AES, the Auger spectra of polymers and of halogenated polymers in particular is discussed. It is shown that the Auger spectra of halogenated polymers have certain characteristics that permit an assessment of whether a polymeric transfer film has been established by sliding contact. The discussion is general and the concepts should be useful in considering the Auger analysis of any polymer. The polymers chosen for this study are the halogenated polymers polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polychlorotrifluorethylene (PCTFE).

  14. Radiobiological Effects of Auger Electrons in the Decay of PLATINUM-195M.

    NASA Astrophysics Data System (ADS)

    Howell, Roger Wells

    The metastable radionuclide Pt-195m decays predominantly by internal conversion (IC) with a half-life of 4 days. The vacancies created in the inner atomic shells by the primary IC decay modes result in copious emission of low energy Auger electrons. The biological effects of these electrons, which have ranges of subcellular dimensions, are of interest to basic and applied radiation biophysics. Using radiolabeled platinum complexes which bind to DNA, one can examine the effect of Pt-195m Auger cascades close to the DNA. Trans -Pt-195m (trans-dichlorodiammineplatinum (II); specific activity 0.5 mCi/mg), a DNA-binding compound, has been synthesized and its effect on the survival of Chinese hamster V79 cells determined. The cellular uptake of Pt-195m reaches a plateau in 3-4 hours and varies nonlinearly with extracellular activity concentration. Following an 18 hour incubation, 75% of the cellular radioactivity is found in the cytoplasm, and 25% in the nucleus. About 42% of the activity in the nucleus is DNA-bound. The activity is eliminated from the cell, postincubation, with a 24 hour half-life. Cell survival data, when corrected for the chemical toxicity of the unlabeled trans-Pt, give a survival curve typical of densely ionizing radiation of high linear energy transfer such as alpha particles. The mean lethal cellular uptake of radioactivity is 0.032 +/- 0.003 pCi/cell at 37% survival. Theoretical calculations of the Pt-195m Auger electron spectrum using Monte Carlo methods indicate about 30 Auger electrons are expected per decay. Dosimetric considerations give a value of 4.8 for the relative biological effectiveness of Pt-195m compared to 250 kVp x-rays. Theoretical Monte Carlo calculations imply that the density of chemical species produced by Auger electrons in liquid water in the immediate vicinity of a Pt-195m decay site is comparable to the density along the track of a 4 MeV alpha particle. This explains qualitatively the efficacy of Pt-195m in causing

  15. A study of native oxides of beta-SiC using Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Chaudhry, M. Iqbal

    1989-01-01

    Thermal and anodic oxide films of beta-SiC are analyzed using Auger electron spectroscopy. Auger depth-composition profiles are obtained in order to determine the chemical composition of the oxide films. The position and shape of silicon spectral peaks are used to estimate the chemical bonding of the oxide constituents. It is found that the wet thermal oxide is almost stoichiometric but contains about 14 pct C. Dry oxide, on the other hand, has less than 3 pct C but is highly nonstoichiometric. The C content in the anodic oxide is 12 pct. Anodic oxide films, like dry-oxide films, are nonstoichiometric. A model of the SiC oxidation process is presented.

  16. Chemical state analysis of grain boundaries in ZnO varistors by Auger electron spectroscopy

    SciTech Connect

    Tanaka, Shigeru ); Akita, Chiyoshi ); Ohashi, Naoki ); Kawai, Jun ); Haneda, Hajime; Tanaka, Junzo )

    1993-07-01

    The chemical state of grain boundaries in Bi[sub 2]O[sub 3]-doped ZnO ceramics was investigated by Auger electron spectroscopy. The additive Bi was segregated into grain boundaries 2 to 3 nm thick, where oxygen deficiency occurred. Auger transitions KL[sub 2,3]L[sub 2,3] for oxygen at the grain boundaries were composed of three peaks whose relative intensities varied with the amount of the segregated Bi. Results calculated using a molecular orbital method suggested that the metal-oxygen bonding state in the grain boundary changed with increased amounts of Bi. The change of the bonding character was considered to be related to the formation of an interfacial state at the grain boundary causing nonlinear current-voltage characteristics. 16 refs., 9 figs.

  17. Nuclear Targeting with an Auger Electron Emitter Potentiates the Action of a Widely Used Antineoplastic Drug.

    PubMed

    Imstepf, Sebastian; Pierroz, Vanessa; Raposinho, Paula; Bauwens, Matthias; Felber, Michael; Fox, Thomas; Shapiro, Adam B; Freudenberg, Robert; Fernandes, Célia; Gama, Sofia; Gasser, Gilles; Motthagy, Felix; Santos, Isabel R; Alberto, Roger

    2015-12-16

    We present the combination of the clinically well-proven chemotherapeutic agent, Doxorubicin, and (99m)Tc, an Auger and internal conversion electron emitter, into a dual-action agent for therapy. Chemical conjugation of Doxorubicin to (99m)Tc afforded a construct which autonomously ferries a radioactive payload into the cell nucleus. At this site, damage is exerted by dose deposition from Auger radiation. The (99m)Tc-conjugate exhibited a dose-dependent inhibition of survival in a selected panel of cancer cells and an in vivo study in healthy mice evidenced a biodistribution which is comparable to that of the parent drug. The homologous Rhenium conjugate was found to effectively bind to DNA, inhibited human Topoisomerase II, and exhibited cytotoxicity in vitro. The collective in vitro and in vivo data demonstrate that the presented metallo-conjugates closely mimic native Doxorubicin. PMID:26473388

  18. Techniques for the correction of topographical effects in scanning Auger electron microscopy

    NASA Technical Reports Server (NTRS)

    Prutton, M.; Larson, L. A.; Poppa, H.

    1983-01-01

    A number of ratioing methods for correcting Auger images and linescans for topographical contrast are tested using anisotropically etched silicon substrates covered with Au or Ag. Thirteen well-defined angles of incidence are present on each polyhedron produced on the Si by this etching. If N1 electrons are counted at the energy of an Auger peak and N2 are counted in the background above the peak, then N1, N1 - N2, (N1 - N2)/(N1 + N2) are measured and compared as methods of eliminating topographical contrast. The latter method gives the best compensation but can be further improved by using a measurement of the sample absorption current. Various other improvements are discussed.

  19. Reduced Auger recombination in single CdSe/CdS nanorods by one-dimensional electron delocalization.

    PubMed

    Rabouw, Freddy T; Lunnemann, Per; van Dijk-Moes, Relinde J A; Frimmer, Martin; Pietra, Francesca; Koenderink, A Femius; Vanmaekelbergh, Daniël

    2013-10-01

    Progress to reduce nonradiative Auger decay in colloidal nanocrystals has recently been made by growing thick shells. However, the physics of Auger suppression is not yet fully understood. Here, we examine the dynamics and spectral characteristics of single CdSe-dot-in-CdS-rod nanocrystals. These exhibit blinking due to charging/discharging, as well as trap-related blinking. We show that one-dimensional electron delocalization into the rod-shaped shell can be as effective as a thick spherical shell at reducing Auger recombination of the negative trion state. PMID:24010869

  20. Sliding of poly(vinyl chloride) on metals studied by Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1974-01-01

    The sliding of polyvinyl chloride on nickel, iron and S-Monel has been studied by Auger electron spectroscopy. Polymer was not transferred to the metals, rather shear appeared to take place at the interface. The metal was progressively chlorinated as the polymer made multiple passes on the surface. The thickness of this chlorine film was the order of one atomic layer. Electron-induced desorption studies indicate that the chlorine is chemisorbed to the metal. These results are interpreted as evidence for mechanically induced and/or thermal degradation of the polymer during sliding. Degradation products of HCl and Cl2 which chemisorb to the metal are evolved near the interface.

  1. Angular dependences in auger electron emission from the Ni(001) face. II. Angular distribution of auger electron emission from the Ni(001) face for different temperatures and different electron energies in M 2,3VV transition

    NASA Astrophysics Data System (ADS)

    Mróz, S.; Mróz, A.; Wieczorek, A.; Fritzsche, V.

    1989-12-01

    Angular-resolved Auger electron spectroscopy (ARAES) was applied for the investigation of the Ni(001) face of both a clean surface and a surface covered with a c(2 × 2) sulphur layer at different sample temperatures. Polar ARAES profiles measured for the NiM 2,3VV transition are presented for the [100] and [110] azimuths, for the full Auger current and for particular Auger energies as well. These latter profiles are theoretically calculated and compared with experiment. An increase of the temperature up to 980 K does not influence appreciably the polar ARAES profiles for the c(2 × 2) {S}/{Ni}(001) sample. It indicates that the atomic structure of the surface investigated is not changed in this temperature region.

  2. A new route to nanoscale tomographic chemical analysis: Focused ion beam-induced auger electron spectrosocpy

    NASA Astrophysics Data System (ADS)

    Parvaneh, Hamed

    This research project is aimed to study the application of ion-induced Auger electron spectroscopy (IAES) in combination with the characteristics of focused ion beam (FIB) microscopy for performing chemical spectroscopy and further evaluate its potential for 3-dimensional chemical tomography applications. The mechanism for generation of Auger electrons by bombarding ions is very different from its electron induced counterpart. In the conventional electron-induced Auger electron spectroscopy (EAES), an electron beam with energy typically in the range 1-10kV is used to excite inner-shell (core) electrons of the solid. An electron from a higher electron energy state then de-excites to fill the hole and the extra energy is then transferred to either another electron, i.e. the Auger electron, or generation of an X-ray (photon). In both cases the emitting particles have charac-teristic energies and could be used to identify the excited target atoms. In IAES, however, large excitation cross sections can occur by promotion of in-ner shell electrons through crossing of molecular orbitals. Originally such phenomenological excitation processes were first proposed [3] for bi-particle gas phase collision systems to explain the generation of inner shell vacancies in violent collisions. In addition to excitation of incident or target atoms, due to a much heavier mass of ions compared to electrons, there would also be a substantial momentum transfer from the incident to the target atoms. This may cause the excited target atom to recoil from the lattice site or alternatively sputter off the surface with the possibility of de-excitation while the atom is either in motion in the matrix or traveling in vacuum. As a result, one could expect differences between the spectra induced by incident electrons and ions and interpretation of the IAE spectra requires separate consideration of both excitation and decay processes. In the first stage of the project, a state-of-the-art mass

  3. Ultrafast dynamics of multiple exciton harvesting in the CdSe-ZnO system: electron injection versus Auger recombination.

    PubMed

    Zídek, Karel; Zheng, Kaibo; Abdellah, Mohamed; Lenngren, Nils; Chábera, Pavel; Pullerits, Tõnu

    2012-12-12

    We study multiple electron transfer from a CdSe quantum dot (QD) to ZnO, which is a prerequisite for successful utilization of multiple exciton generation for photovoltaics. By using ultrafast time-resolved spectroscopy we observe competition between electron injection into ZnO and quenching of multiexcitons via Auger recombination. We show that fast electron injection dominates over biexcitonic Auger recombination and multiple electrons can be transferred into ZnO. A kinetic component with time constant of a few tens of picoseconds was identified as the competition between injection of the second electron from a doubly excited QD and a trion Auger recombination. Moreover, we demonstrate that the multiexciton harvesting efficiency changes significantly with QD size. Within a narrow QD diameter range from 2 to 4 nm, the efficiency of electron injection from a doubly excited QD can vary from 30% to 70% in our system. PMID:23163524

  4. An experimental comparison of the K- and L-Auger electron spectra generated in the decays of 140Nd and 111In.

    PubMed

    Yakushev, E A; Kovalík, A; Filosofov, D V; Korolev, N A; Lebedev, N A; Lubashevski, A V; Rösch, F; Novgorodov, A F

    2005-03-01

    The low-energy electron spectra generated in the decay of 140Nd have been measured using a combined electrostatic spectrometer adjusted to the 4, 7, and 35 eV instrumental resolution. In order to estimate the therapeutic potential of low-energy electrons associated with the decay of 140Nd, similar experiments have been performed with 111In. Relative Auger electron intensity ratios per decay are: 111In(K-Auger)/140Nd(K-Auger)=1.47(12), 111In(L-Auger) /140Nd(L-Auger)=1.1(4), and 111In(L-Auger [2.8-7 keV])/140Nd(L-Auger [2.8-7 keV])=0.24(11). The obtained K-Auger group intensity ratios have been compared with results of calculations. The good agreement found for the experimental and estimated values indicates that such information can be also derived using available nuclear and atomic data. The relative intensity of L-Auger electrons emitted within the 2.8-7 keV interval is higher for 140Nd by a factor of about 4 compared to 111In. As the L-Auger emission is dominating relative to that of the K-Auger group, this implicates that any potential endotherapeutic strategy using 140Nd-labelled targeting vectors requires a maximum accumulation of the endoradiotherapeutical close to the cell nucleus or the DNA of the tumour cell. PMID:15607923

  5. Auger-electron angular distributions calculated without the two-step approximation: Calculation of angle-resolved resonant Auger spectra of C2 H2

    NASA Astrophysics Data System (ADS)

    Colle, Renato; Embriaco, Davide; Massini, Michol; Simonucci, Stefano; Taioli, Simone

    2004-10-01

    Analytic expressions for the direct, resonant, and interference contributions to the differential cross section of a resonant Auger process, produced by the inner-shell photoionization of a linear molecule either “fixed in space” or belonging to a gas of randomly oriented molecules, have been derived following Dill’s procedures [ Dill , Phys. Rev. Lett. 45, 1393 (1980) ], but going beyond the two-step approximation. Angle-resolved Auger spectra of the C2H2 molecule measured on top of the C1s→π* resonance [ Kivimäki , J. Phys. B 30, 4279 (1997) ] have been calculated together with asymmetry parameters, analyzing also the different contributions to the electron angular distributions.

  6. The application of reflected light microscopy, scanning electron microscopy-energy dispersive spectroscopy, Auger electron spectroscopy and electron microprobe analysis to the study of dusts

    SciTech Connect

    Hagni, A.M.; Hagni, R.D. . Dept. of Geology and Geophysics)

    1993-03-01

    Over 500,000 tons of electric arc furnace (EAF) dust is generated each year in the US. The mineralogy and characterization of this dust is being studied to determine the phases and relationships of the valuable zinc, the hazardous lead, cadmium, and chromium, and the deleterious chlorine and fluorine. EAF dust averages 15--20% zinc and is therefore a potential source for 100,000 tons of zinc per year. The major mineralogical phases of EAF dust are franklinite (ZnFe[sub 2]O[sub 4]), magnetite (FeFe[sub 2]O[sub 4]), jacobsite (MnFe[sub 2]O[sub 4]), solid solutions between franklinite-magnetite-jacobsite, and zincite (ZnO). Franklinite, magnetite, and jacobsite solid solutions commonly are cruciform or dendritic crystals in a Ca-Fe-Si matrix and contain up to 5% chromium. Magnetite also occurs as spheres partially oxidized to hematite (Fe[sub 2]O[sub 3]) along its octahedral planes. The dust particles are predominantly in the form of spheres and broken spheres, ranging in size from 200 [mu]m to less than 1 [mu]m. Although many spheres are in the size ranges of 40--50 [mu]m and 10--20 [mu]m, most are less than 1 [mu]m in diameter. Automated scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) probed 118 particles in search of chlorine phases. Chlorine-bearing lime (CaO) was identified by that SEM study. In addition, chlorine is present as hydrophylite (CaCl[sub 2]) and sylvite (KCl). Auger electron spectroscopy (AES) was used to sputter the outer 180[angstrom] layer of the dust particles to search for the possible presence of cotunnite (PbCl[sub 2]) coatings, but none were detected. Minor phases detected include chalcopyrite (CuFeS[sub 2]), sphalerite (ZnS), pyrite (FeS[sub 2]), and coke.

  7. Channel-resolved photo- and Auger-electron spectroscopy of halogenated hydrocarbons

    NASA Astrophysics Data System (ADS)

    Ablikim, Utuq; Kaderiya, B.; Kumarapan, V.; Kushawaha, R.; Rudenko, A.; Rolles, D.; Xiong, H.; Berrah, N.; Bomme, C.; Savelyev, E.; Kilcoyne, D.

    2016-05-01

    Inner-shell photoelectron and Auger electron spectra of polyatomic molecules such as halogenated hydrocarbons are typically hard to interpret and assign due to many overlapping states that form broad bands even in high-resolution measurements. With the help of electron-ion-ion coincidence measurements performed using the velocity map imaging technique, we are able to detect high-energy (<= 150 eV) photo- and Auger electrons in coincidence with two- or many-body ionic fragmentation channels. Such channel-resolved measurements allow disentangling the overlapping electronic structures and help assigning individual components of the electron spectra to specific potential surfaces and final states. In this work, we present measurements on CH3 I, CH2 IBr, and CH2 ICl molecules in the gas-phase using soft x-ray light provided by the Advanced Light Source at LBNL. This project is supported by the DOE, Office of Science, BES, Division of Chemical, Geological and Biological Sciences under Award Number DE-FG02-86ER13491 (U.A., B.K., V.K., A.R., D.R.) and Award Number DE-SC0012376 (H.X., N.B.).

  8. On the interatomic electronic processes following Auger decay in neon dimer.

    PubMed

    Stoychev, Spas D; Kuleff, Alexander I; Tarantelli, Francesco; Cederbaum, Lorenz S

    2008-08-21

    The accessible relaxation channels of the electronic states of Ne(++)-Ne and Ne(3+)-Ne populated by KLL Auger decay are studied. In particular, we address the "direct" and "exchange" interatomic Coulombic decays (ICDs) and the electron-transfer-mediated decay following the population of one-site states Ne(++)(2s(-2))-Ne and Ne(++)(2s(-1)2p(-1) (1)P)-Ne. Radiative charge transfer of the low lying Ne(++)(2p(-2))-Ne states, three-electron ICD process from the Ne(++)(2s(-2))-Ne states, as well as charge transfer at the points of curve crossing of the lowest in energy Ne(3+)(2p(-3))-Ne states are also discussed. To carry out the present study, we have calculated the potential energy curves (from 1.75 to 5.00 A) of the ground state Ne(2), the core ionized state Ne(+)(1s(-1))-Ne, and the dicationic and tricationic states with energies in the range of 45-140 eV using accurate ab initio methods and basis sets. Apart from being of interest by themselves, the results obtained may be helpful in interpreting the recent measurements of interatomic electronic processes following Auger decay in neon dimer [K. Kreidi et al., J. Phys. B 41, 101002 (2008)]. PMID:19044767

  9. New electronics for the surface detectors of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Kleifges, M.

    2016-07-01

    The Pierre Auger Observatory is the largest installation worldwide for the investigation of ultra-high energy cosmic rays. Air showers are detected using a hybrid technique with 27 fluorescence telescopes and 1660 water-Cherenkov detectors (WCD) distributed over about 3000 km2. The Auger Collaboration has decided to upgrade the electronics of the WCD and complement the surface detector with scintillators (SSD). The objective is to improve the separation between the muonic and the electron/photon shower component for better mass composition determination during an extended operation period of 8-10 years. The surface detector electronics records data locally and generates time stamps based on the GPS timing. The performance of the detectors is significantly improved with a higher sampling rate, an increased dynamic range, new generation of GPS receivers, and FPGA integrated CPU power. The number of analog channels will be increased to integrate the new SSD, but the power consumption needs to stay below 10 W to be able to use the existing photovoltaic system. In this paper, the concept of the additional SSD is presented with a focus on the design and performance of the new surface detector electronics.

  10. Stability and dissociation dynamics of N2 (++) ions following core ionization studied by an Auger-electron-photoion coincidence method.

    PubMed

    Iwayama, H; Kaneyasu, T; Hikosaka, Y; Shigemasa, E

    2016-07-21

    An Auger-electron-photoion coincidence (AEPICO) method has been applied to study the stability and dissociation dynamics of dicationic states after the N K-shell photoionization of nitrogen molecules. From time-of-flight and kinetic energy analyses of the product ions, we have obtained coincident Auger spectra associated with metastable states of N2 (++) ions and dissociative states leading to N2 (++) → N(+) + N(+) and N(++) + N. To investigate the production of dissociative states, we present two-dimensional AEPICO maps which reveal the correlations between the binding energies of the Auger final states and the ion kinetic energy release. These correlations have been used to determine the dissociation limits of individual Auger final states. PMID:27448885

  11. X-ray fluorescence/Auger-electron coincidence spectroscopy of vacancy cascades in atomic argon

    SciTech Connect

    Arp, U.; LeBrun, T.; Southworth, S.H.; Jung, M.; MacDonald, M.A.

    1996-12-01

    Argon L{sub 2.3}-M{sub 2.3}M{sub 2.3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons.

  12. Surface change in titanium subhydride between 25 and 700/sup 0/C studied by Auger electron spectroscopy and x-ray photoelectron spectroscopy

    SciTech Connect

    Wang, P.S.; Carlson, R.S.; Wittberg, T.N.

    1982-07-09

    The surface sensitive spectroscopic techniques of Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) have been applied to the study of the oxide dissolution of titanium and titanium subhydride. In an earlier study using AES, it was shown that the rate of oxygen dissolution into titanium increased sharply at approx. 350/sup 0/C. These data correlated well with physical property measurements that indicated an exothermic reaction was occurring at these temperatures which corresponded to the reaction of free Ti with atmospheric oxygen. In the present study the work has been expanded to include studies of TiH/sub x/ (x = 1.15, 1.62). It has been found that dissolution of the native oxide on titanium subhydride occurs at a temperature substantially higher (approx. 500/sup 0/C) than that required for titanium. It appears that the outward diffusion of hydrogen is inhibiting the inward diffusion of oxygen on the sub-hydride samples at temperatures below 500/sup 0/C.

  13. Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL

    NASA Astrophysics Data System (ADS)

    Sanchez-Gonzalez, A.; Barillot, T. R.; Squibb, R. J.; Kolorenč, P.; Agaker, M.; Averbukh, V.; Bearpark, M. J.; Bostedt, C.; Bozek, J. D.; Bruce, S.; Carron Montero, S.; Coffee, R. N.; Cooper, B.; Cryan, J. P.; Dong, M.; Eland, J. H. D.; Fang, L.; Fukuzawa, H.; Guehr, M.; Ilchen, M.; Johnsson, A. S.; Liekhus-S, C.; Marinelli, A.; Maxwell, T.; Motomura, K.; Mucke, M.; Natan, A.; Osipov, T.; Östlin, C.; Pernpointner, M.; Petrovic, V. S.; Robb, M. A.; Sathe, C.; Simpson, E. R.; Underwood, J. G.; Vacher, M.; Walke, D. J.; Wolf, T. J. A.; Zhaunerchyk, V.; Rubensson, J.-E.; Berrah, N.; Bucksbaum, P. H.; Ueda, K.; Feifel, R.; Frasinski, L. J.; Marangos, J. P.

    2015-12-01

    We report the first measurement of the near oxygen K-edge auger spectrum of the glycine molecule. Our work employed an x-ray free electron laser as the photon source operated with input photon energies tunable between 527 and 547 eV. Complete electron spectra were recorded at each photon energy in the tuning range, revealing resonant and non-resonant auger structures. Finally ab initio theoretical predictions are compared with the measured above the edge auger spectrum and an assignment of auger decay channels is performed.

  14. Atomic and Molecular Photoelectron and Auger Electron SpectroscopyStudies Using Synchrotron Radiation

    SciTech Connect

    Southworth, Stephen H.

    1982-01-01

    Electron spectroscopy, combined with synchrotron radiation, was used to measure the angular distributions of photoelectrons and Auger electrons from atoms and molecules as functions of photon energy. The branching ratios and partial cross sections were a 130 measured in certain cases. By comparison with theoretical calculations, the experimental results are interpreted in terms of the characteristic electronic structure and ionization dynamics of the atomic or molecular sample. The time structure of the synchrotron radiation source was used to record time-of-flight (TOF) spectra o f the ejected electrons. The ''a double-angle-TOF'' method for the measurement of photoelectron angular distributions is discussed. This technique offers the advantages of increased electron collect ion efficiency and the elimination of certain systematic errors. Several results were obtained for Xe using photon energies in the range hv {approx_equal} 60-190 eV, where excitation and ionization of the inner-subshell 4d electrons dominates. The 4d asymmetry parameter {beta} exhibits strong oscillations with energy, in agreement with several theoretical calculations. As predicted, the 5p asymmetry parameter was observed to deviate strongly from that calculated using the independent-electron model, due to intershell correlation with the 4d electrons.

  15. Auger decay of 1{sigma}{sub g} and 1{sigma}{sub u} hole states of the N{sub 2} molecule. II. Young-type interference of Auger electrons and its dependence on internuclear distance

    SciTech Connect

    Cherepkov, N. A.; Semenov, S. K.; Schoeffler, M. S.; Titze, J.; Petridis, N.; Jahnke, T.; Cole, K.; Schmidt, L. Ph. H.; Czasch, A.; Jagutzki, O.; Schmidt-Boecking, H.; Doerner, R.; Akoury, D.; Williams, J. B.; Landers, A. L.; Osipov, T.; Lee, S.; Prior, M. H.; Belkacem, A.; Weber, Th.

    2010-08-15

    Theoretical two-center interference patterns produced (i) by the K-shell photoionization process of the N{sub 2} molecule and (ii) by the Auger decay process of the K-shell hole state of the N{sub 2} molecule are compared for the case of equal photo- and Auger-electron energies of about 360 eV. The comparison shows that both the angular distribution of the photoelectrons and the angular distribution of the Auger electrons of equal energy in the molecular frame are primarily defined by the Young interference. The experimental data for the angular resolved K-shell Auger electrons as a function of the kinetic-energy release (KER) obtained earlier [Phys. Rev. A 81, 043426 (2010)] have been renormalized in order to visualize the angular variation in the regions of low Auger-electron intensities. That renormalized data are compared with the corresponding theoretical results. From the known behavior of the potential energy curves, the connection between the KER and the internuclear distance can be established. Since the Young interference pattern is sensitive to the internuclear distance in the molecule, from the measured KER dependence of the Young interference pattern one can trace the behavior of the Auger-electron angular distribution for different molecular terms as a function of internuclear distance. The results of that analysis are in a good agreement with the corresponding theoretical predictions.

  16. WE-E-BRE-08: Impact of IUdR in Rat 9L Glioma Cell Survival for 25–35 KeV Photo-Activated Auger Electron Therapy

    SciTech Connect

    Alvarez, D; Hogstrom, K; Brown, T; Dugas, J; Varnes, M; Matthews, K

    2014-06-15

    Purpose: To determine the biological effect from Auger electrons with 9% and 18% iododeoxyuridine (IUdR) incorporated into the DNA of rat 9L glioma cells at photon energies above and below the K-edge of iodine (33.2 keV). Methods: Rat 9L glioma cell survival versus dose curves with 0%, 9%, and 18% thymidine replacement with IUdR were measured using four irradiation energies (4 MV x-rays; monochromatic 35, 30, and 25 keV synchrotron photons). For each of 11 conditions (Energy, %IUdR) survival curves were fit to the data (826 cell cultures) using the linear-quadratic model. The ratio of doses resulting in 10% survival gave sensitization enhancement ratios (SER10) from which contributions due to linear-energy transfer (LET), radiosensitization (RS), and Auger effect (AE) were extracted. Results: At 35, 30, and 25 keV, SER10,LET values were 1.08±0.03, 1.22±0.02, and 1.37±0.02, respectively. At 4 MV SER10,RS values for 9% and 18% IUdR were 1.28±0.02 and 1.40±0.02, respectively. Assuming LET effects are independent of %IUdR and radiosensitization effects are independent of energy, SER10,AE values for 18% IUdR at 35, 30, and 25 keV were 1.35±0.05, 1.06±0.03, and 0.98±0.03, respectively; values for 9% IUdR at 35 and 25 keV were 1.01±0.04 and 0.82±0.02, respectively. Conclusion: For 18% IUdR the radiosensitization effect of 1.40 and the Auger effect of 1.35 at 35 keV are equally important to the combined effect of 1.90. No measureable Auger effect was observed for energies below the K-edge at 20 and 25 keV, as expected. The insignificant Auger effect at 9% IUdR was not expected. Additional data (40–70 keV) and radiobiological modeling are being acquired to better understand the energy dependence of Auger electron therapy with IUdR. Funding support in part by the National Science Foundation Graduate Research Fellowship Program and in part by Contract No. W81XWH-10-1-0005 awarded by the U.S. Army Research Acquisition Activity. This paper does not necessarily

  17. Investigation of the electron structure of ZnO by the GGA and mBJ calculations associated with the characterization techniques AES and EELS

    NASA Astrophysics Data System (ADS)

    Mokadem, A.; Bouslama, M.; Benhelal, O.; Assali, A.; Ghaffour, M.; Chelahi Chikr, Z.; Boulenouar, K.; Boubaia, A.

    2014-03-01

    The semiconductor ZnO of large gap of 3,4 eV is of great interest for the technological applications as chemical sensors, UV light emission, optical memories, laser emission, solar cells, etc. These applications depend on the electron structure of material. We adopt the density functional theory (DFT) calculation by using the program Wien2K, within the Generalized Gradient Approximation (GGA) and modified Becke-Johnson (mBJ) for studying the electron behavior of ZnO. The features of the valence band derived from the hybridization of Zn-3d and O-2p states. The electron charge density calculated by these simulation methods indicates a charge transfer between zinc and oxygen inducing a difference in electronegativity between both species (Zn and O), responsible to ionic character of bonding in ZnO. The predictions based on the GGA and mBJ calculations are confirmed by the results of the experimental spectroscopic analysis Auger Electron Spectroscopy (AES) and Electron Energy Loss Spectroscopy (EELS).

  18. Relationship Between Chromatin Structure and Sensitivity to Molecularly Targeted Auger Electron Radiation Therapy

    SciTech Connect

    Terry, Samantha Y.A.

    2012-07-15

    Purpose: The open structure of euchromatin renders it susceptible to DNA damage by ionizing radiation (IR) compared with compact heterochromatin. The effect of chromatin configuration on the efficacy of Auger electron radiotherapy was investigated. Methods and Materials: Chromatin structure was altered in MDA-MB-468 and 231-H2N human breast cancer cells by suberoylanilide hydroxamic acid (SAHA), 5-aza-2-deoxycytidine, or hypertonic treatment. The extent and duration of chromatin structural changes were evaluated using the micrococcal nuclease assay. DNA damage ({gamma}H2AX assay) and clonogenic survival were evaluated after exposure to {sup 111}In-DTPA-hEGF, an Auger electron-emitting radiopharmaceutical, or IR. The intracellular distribution of {sup 111}In-DTPA-hEGF after chromatin modification was investigated in cell fractionation experiments. Results: Chromatin remained condensed for up to 20 minutes after NaCl and in a relaxed state 24 hours after SAHA treatment. The number of {gamma}H2AX foci per cell was greater in MDA-MB-468 and 231-H2N cells after IR (0.5 Gy) plus SAHA (1 {mu}M) compared with IR alone (16 {+-} 0.6 and 14 {+-} 0.3 vs. 12 {+-} 0.4 and 11 {+-} 0.2, respectively). More {gamma}H2AX foci were observed in MDA-MB-468 and 231-H2N cells exposed to {sup 111}In-DTPA-hEGF (6 MBq/{mu}g) plus SAHA vs. {sup 111}In-DTPA-hEGF alone (11 {+-} 0.3 and 12 {+-} 0.7 vs. 9 {+-} 0.4 and 7 {+-} 0.3, respectively). 5-aza-2-deoxycytidine enhanced the DNA damage caused by IR and {sup 111}In-DTPA-hEGF. Clonogenic survival was reduced in MDA-MB-468 and 231-H2N cells after IR (6 Gy) plus SAHA (1 {mu}M) vs. IR alone (0.6% {+-} 0.01 and 0.3% {+-} 0.2 vs. 5.8% {+-} 0.2 and 2% {+-} 0.1, respectively) and after {sup 111}In-DTPA-hEGF plus SAHA compared to {sup 111}In-DTPA-hEGF alone (21% {+-} 0.4% and 19% {+-} 4.6 vs. 33% {+-} 2.3 and 32% {+-} 3.7). SAHA did not affect {sup 111}In-DTPA-hEGF nuclear localization. Hypertonic treatment resulted in fewer {gamma}H2AX foci per cell

  19. Nonequilibrium dynamics of photoexcited electrons in graphene: Collinear scattering, Auger processes, and the impact of screening

    NASA Astrophysics Data System (ADS)

    Tomadin, Andrea; Brida, Daniele; Cerullo, Giulio; Ferrari, Andrea C.; Polini, Marco

    2013-07-01

    We present a combined analytical and numerical study of the early stages (sub-100-fs) of the nonequilibrium dynamics of photoexcited electrons in graphene. We employ the semiclassical Boltzmann equation with a collision integral that includes contributions from electron-electron (e-e) and electron-optical phonon interactions. Taking advantage of circular symmetry and employing the massless Dirac fermion (MDF) Hamiltonian, we are able to perform an essentially analytical study of the e-e contribution to the collision integral. This allows us to take particular care of subtle collinear scattering processes—processes in which incoming and outgoing momenta of the scattering particles lie on the same line—including carrier multiplication (CM) and Auger recombination (AR). These processes have a vanishing phase space for two-dimensional MDF bare bands. However, we argue that electron-lifetime effects, seen in experiments based on angle-resolved photoemission spectroscopy, provide a natural pathway to regularize this pathology, yielding a finite contribution due to CM and AR to the Coulomb collision integral. Finally, we discuss in detail the role of physics beyond the Fermi golden rule by including screening in the matrix element of the Coulomb interaction at the level of the random phase approximation (RPA), focusing in particular on the consequences of various approximations including static RPA screening, which maximizes the impact of CM and AR processes, and dynamical RPA screening, which completely suppresses them.

  20. Combined AES, LEED, SEM and TEM characterizations of CuSi(100) interfaces

    NASA Astrophysics Data System (ADS)

    Hanbücken, M.; Métois, J. J.; Mathiez, P.; Salvan, F.

    1985-10-01

    CuSi(100) interfaces prepared under UHV at different substrate temperatures ( TS) have been characterized using in-situ Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) as well as ex-situ scanning and transmission electron microscopy (SEM, TEM). At room temperature (RT), the film grows in a layer by layer like mode. With increasing TS, the intensity of the Cu M 2,3VV (61 eV) Auger transition decreases and at TS = 500°C no Cu Auger signal could be measured below θ ˜ 100. Yet SEM and TEM observations of these deposits show islands in epitaxial relation with the substrate. It can be determined from TEM images that these islands are covered with a Si skin ( ˜ 50 Å; thick) and that they are deeply implanted in the Si substrate. This explains the AES measurements.

  1. Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5–18 eV) electron interactions with DNA

    PubMed Central

    Rezaee, Mohammad; Hunting, Darel J.; Sanche, Léon

    2015-01-01

    Purpose The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides. Methods Absorbed dose and stopping cross section for the Auger electrons of 5–18 eV emitted by 125I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single- and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure–response curves for induction of DNA strand breaks. Results For a single decay of 125I within DNA, the Auger electrons of 5–18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm3 volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break. Conclusions Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should be considered in the

  2. Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5–18 eV) electron interactions with DNA

    SciTech Connect

    Rezaee, Mohammad Hunting, Darel J.; Sanche, Léon

    2014-07-15

    Purpose: The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides. Methods: Absorbed dose and stopping cross section for the Auger electrons of 5–18 eV emitted by{sup 125}I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single- and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure–response curves for induction of DNA strand breaks. Results: For a single decay of{sup 125}I within DNA, the Auger electrons of 5–18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm{sup 3} volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break. Conclusions: Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should

  3. Sputter-induced erosion of alkali metal surfaces - AES, XPS and SIMS studies

    SciTech Connect

    Krauss, A.R.

    1982-01-01

    This paper will discuss the manner in which the techniques of Auger-electron spectroscopy (AES), X-ray-photoelectron spectroscopy (XPS), secondary-ion mass spectroscopy (SIMS) and ion-scattering spectroscopy (ISS) may be used to study the use of high secondary-ion-yield surfaces as a means of reducing plasma-impurity influx in magnetic-confinement fusion devices.

  4. Interference of electron pairs in photoinduced N4,5 - O1O2,3 Auger decay in xenon

    NASA Astrophysics Data System (ADS)

    Žitnik, M.; Bučar, K.; Lablanquie, P.; Penent, F.; Palaudoux, J.; Andric, L.; Hikosaka, Y.; Ito, K.

    2012-11-01

    We observed an interference originating from coincidence detection of two indistinguishable electron pairs emitted upon photoionization of 4d electron in Xe. At 89.9 eV photon impact the energy of photoelectron ejected from 4d5/2 orbital equals energy of Auger electron emitted in decay of 4d3/2 hole into the [5s5p1P] state, and for the same final state the energy of the 4d3/2 photoelectron equals the Auger electron energy in decay of 4d5/2 hole. An angle-integrated coincidence yield as a function of photon energy is measured with the magnetic bottle time-of-flight spectrometer and shows a peak at the expected energy position.

  5. Diffraction and holography with photoelectrons and Auger electrons: Some new directions

    SciTech Connect

    Fadley, C.S. Lawrence Berkeley Lab., CA )

    1992-06-01

    The current status of photoelectron and Auger-electron diffraction is reviewed, with emphasis on new directions of activity. The use of forward scattering in the study of adsorbed molecules, epitaxial overlayers, and clean surfaces is one of the most developed applications, and one that will become more powerful as higher energy resolution and perhaps spin analysis are used to resolve emitters on the basis of chemical state, position at a surface, or magnetic state. The use of larger data sets spanning a considerable fraction of the solid angle above a surface will also much enhance the structural information available, for example, in the growth of epitaxial layers or nanostructures on surfaces. Detailed fitting of experimental data to theoretical calculations based upon either single scattering or multiple scattering should also provide more rich structural information, including such parameters as substrate interlayer relaxation. Surface phase transitions in which near-surface layers become highly disordered can also be studied, with results that are complementary to those from such techniques as low energy electron diffraction and medium energy ion scattering. Short-range magnetic order also can be probed by somehow resolving the spin of the outgoing electrons, e.g. by using multiplet-split core levels.

  6. Association of ionospheric storms and substorms of Global Electron Content with proxy AE index

    NASA Astrophysics Data System (ADS)

    Yenen, S. D.; Gulyaeva, T. L.; Arikan, F.; Arikan, O.

    2015-10-01

    Storm time modeling of Global Electron Content (GEC) calculated from GIM-TEC for 1999-2013 is associated with new proxy of Auroral Electrojet variability expressed as a smoothed and normalized Auroral Electrojet index (AEsn). The variability in GEC is captured by the computation of DGEC which is obtained by taking the hourly ratio of instant GEC to median of GEC values at the same hour of 7 preceding days. The storm onset is determined by a joint analysis of variations in IMF-B magnitude, its derivative (dB/dt) and direction of IMF-Bz together with sudden increase in AE exceeding 900 nT. The start of the pre-storm period is chosen to be 7 h prior to the storm onset time and the storm recovery period ends 41 h after the storm onset. The hourly AEsn is related to DGEC during the storm period through a polynomial whose coefficients are estimated in the linear least squares sense. Estimated coefficients are examined and grouped with respect to different kinds of auroral storms. Examples of modeling methodology are provided using four different kinds of intense storms and substorms, namely, Positive Arctic, Positive Antarctic, Negative Arctic and Negative Antarctic that occurred between 1999 and 2013. The estimated coefficients for storm periods are compared with those of non-storm periods. It is observed that the positive correlation between the increase of AE and GEC can be a promising precursor of space weather variability.

  7. Characterization of ion beam modified ceramic wear surfaces using Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Wei, W.; Lankford, J.

    1987-01-01

    An investigation of the surface chemistry and morphology of the wear surfaces of ceramic material surfaces modified by ion beam mixing has been conducted using Auger electron spectroscopy and secondary electron microscopy. Studies have been conducted on ceramic/ceramic friction and wear couples made up of TiC and NiMo-bonded TiC cermet pins run against Si3N4 and partially stabilized zirconia disc surfaces modified by the ion beam mixing of titanium and nickel, as well as ummodified ceramic/ceramic couples in order to determine the types of surface changes leading to the improved friction and wear behavior of the surface modified ceramics in simulated diesel environments. The results of the surface analyses indicate that the formation of a lubricating oxide layer of titanium and nickel, is responsible for the improvement in ceramic friction and wear behavior. The beneficial effect of this oxide layer depends on several factors, including the adherence of the surface modified layer or subsequently formed oxide layer to the disc substrate, the substrate materials, the conditions of ion beam mixing, and the environmental conditions.

  8. Measurement of the Spectral Distribution of Low Energy Electrons emitted as a result of MVV Auger Transition in Cu(100)

    NASA Astrophysics Data System (ADS)

    Satyal, Suman; Joglekar, P. V.; Shastry, K.; Weiss, A. H.; Hulbert, S. L.

    2011-10-01

    Auger Photoelectron Coincidence Spectroscopy (APECS) was used to investigate the physics of the Low Energy tail (LET) region of the Auger spectrum of a Cu (100) sample. A beam of 200eV photons was incident on the sample and two Cylindrical Mirror Analyzers (CMA's) were used to select the energy of electrons emitted from the sample. An APECS spectra was obtained with one of the CMA's fixed at the energy 136.25eV, which corresponds to the core photoemission peak. The APECS spectra contains the contributions from electrons excited by the MVV Auger transition plus a background due to true coincidences between photo-emitted valence band electrons that undergo inelastic scattering and transfer part of their energy with other valence electrons. Coincidence measurements were made with the fixed analyzer set at various energies between the core and the valence band. These measurements were used to obtain an estimate of the background due to the inelastically scattered valence band electrons.

  9. Surface photovoltage and Auger electron spectromicroscopy studies of HfO2/SiO2/4H-SiC and HfO2/Al2O3/4H-SiC structures

    NASA Astrophysics Data System (ADS)

    Domanowska, A.; Miczek, M.; Ucka, R.; Matys, M.; Adamowicz, B.; Żywicki, J.; Taube, A.; Korwin-Mikke, K.; Gierałtowska, S.; Sochacki, M.

    2012-08-01

    The electronic and chemical properties of the interface region in the structures obtained by the passivation of epitaxial n-type 4H-SiC layers with bilayers consisting of a 5 nm-thick SiO2 or Al2O3 buffer film and high-κ HfO2 layer were investigated. The main aim was to estimate the influence of the passivation approach on the interface effective charge density (Qeff) from the surface photovoltage (SPV) method and, in addition to determine the in-depth element distribution in the interface region from the Auger electron spectroscopy (AES) combined with Ar+ ion profiling. The structure HfO2/SiO2/4H-SiC exhibited slightly superior electronic properties in terms of Qeff (in the range of -1011 q cm-2).

  10. Production of Mg and Al Auger electrons by noble gas ion bombardment of Mg and Al surfaces

    NASA Technical Reports Server (NTRS)

    Ferrante, J.; Pepper, S. V.

    1976-01-01

    Relative production efficiencies of Mg and Al Auger electrons by He, Ne, Ar, Kr, and Xe ion bombardment are reported as a function of ion energy for energies not exceeding 3 keV. The experimental apparatus employed consisted of a LEED-Auger system equipped with an ion gun and a four-grid retarding-potential analyzer. It is found that: (1) the shape of the ion-excited Auger signal was independent of the rare gas and quite symmetric; (2) the Al signal was about an order of magnitude smaller than the Mg signal for a given bombarding species and ion-gun voltage; (3) no signal was observed for He(+) bombardment under any of the experimental conditions; (4) signal strengths were independent of temperature and ion dose; (5) the Auger production efficiencies differed by no more than a factor of two among the different gases - except for He(+) - on a given metal; (6) all the signal strengths increased with increasing ion-gun voltage, with no maximum exhibited; and (7) the apparent threshold energy for the Al signal was higher than that for the Mg signal. The differences between the results for the two metals are attributed to the fact that the Al 2p orbital lies deeper in energy and closer to the nucleus than the corresponding Mg orbital.

  11. The beta-SiC(100) surface studied by low energy electron diffraction, Auger electron spectroscopy, and electron energy loss spectra

    NASA Technical Reports Server (NTRS)

    Dayan, M.

    1986-01-01

    The beta-SiC(100) surface has been studied by low energy electron diffraction, Auger electron spectroscopy, high resolution electron energy loss spectra (HREELS), and core level excitation EELS. Two new Si-terminated phases have been discovered, one with (3 x 2) symmetry, and the other with (2 x 1) symmetry. Models are presented to describe these phases. New results, for the C-rich surface, are presented and discussed. In addition, core level excitation EELS results are given and compared with theory.

  12. Reaction of sulfur dioxide with modified 440C, studied by Auger electron spectroscopy and depth profiling

    NASA Technical Reports Server (NTRS)

    Ferrante, J.

    1975-01-01

    Auger electron spectroscopy and sputtering were used to study the interaction of SO2 with modified 440C, which is a nominally 77-wt%-Fe, 14-wt%-Cr, and 4-wt%-Mo bearing steel with C, S, Si, Ni, V, P, and Mn making up the balance. The sample was polycrystalline. Three temperatures were used: room temperature, 500 C, and 600 C. The reaction time was varied from 30 minutes to 2 hours. A surface cleaned of oxides was the starting point for each reaction. For reactions at 500 C, the major constituents Cr, O, Fe, and S were present in the surface film. At 600 C, the principal constituents of the film were Cr, O, and S with no Fe present. Therefore, a transition in film composition occurred between 500 and 600 C. Oxides were the primary constituents of the films at both temperatures. Room-temperature reactions indicated that SO2 adsorbed dissociatively, with approximately equal quantities of S and O on the surface. For the same reaction time (1 hr) and pressure, a strong temperature dependence of film thickness was observed. The film formed at 600 C was approximately seven times thicker than that formed at 500 C.

  13. Apparatus for measuring the stopping power of active materials evaporated in situ and characterized by Auger electron spectrometry and Rutherford backscattering

    NASA Astrophysics Data System (ADS)

    Semrad, D.; Bauer, P.; Eder, K.; Obermann, W.

    1986-07-01

    An ultrahigh-vacuum scattering chamber working in the low 10-9-mbar range is described. It is attached to a standard O-ring sealed beam transport system of an electrostatic accelerator. Twelve targets can be prepared in situ, one by one, by evaporating the material onto backings, which are mounted on tiltable target holders on a wheel. Backscattering spectra are obtained from these targets and the stopping cross section is deduced from their widths. A cooled high-resolution surface barrier detector is used for this purpose. The integral concentrations of light impurities in the target are obtained using Rutherford backscattering (RBS), whereas Auger electron spectrometry (AES) together with a sputtering device is used to determine the depth composition. As a test of the assembly we determined the stopping power of aluminum for protons and deuterons, respectively. The results are compared to published tables based upon fits to experiments. The influence of impurities on the result is discussed for an aluminum target prepared under standard evaporation conditions.

  14. Apparatus for measuring the stopping power of active materials evaporated in situ and characterized by Auger electron spectrometry and Rutherford backscattering

    SciTech Connect

    Semrad, D.; Bauer, P.; Eder, K.; Obermann, W.

    1986-07-01

    An ultrahigh-vacuum scattering chamber working in the low 10/sup -9/-mbar range is described. It is attached to a standard O-ring sealed beam transport system of an electrostatic accelerator. Twelve targets can be prepared in situ, one by one, by evaporating the material onto backings, which are mounted on tiltable target holders on a wheel. Backscattering spectra are obtained from these targets and the stopping cross section is deduced from their widths. A cooled high-resolution surface barrier detector is used for this purpose. The integral concentrations of light impurities in the target are obtained using Rutherford backscattering (RBS), whereas Auger electron spectrometry (AES) together with a sputtering device is used to determine the depth composition. As a test of the assembly we determined the stopping power of aluminum for protons and deuterons, respectively. The results are compared to published tables based upon fits to experiments. The influence of impurities on the result is discussed for an aluminum target prepared under standard evaporation conditions.

  15. Prominent conjugate processes in the PCI recapture of photoelectrons revealed by high resolution Auger electron measurements of Xe

    NASA Astrophysics Data System (ADS)

    Azuma, Yoshiro; Kosugi, Satoshi; Suzuki, Norihiro; Shigemasa, Eiji; Iwayama, Hiroshi; Koike, Fumihiro

    2016-05-01

    The Xe (N5O2 , 3O2 , 3) Auger electron spectrum originating from 4d5/ 2 - 1 photoionization was measured with the photon energy tuned very close above the ionization threshold. As the photon energy approached the 4d5/ 2 - 1 photoionization threshold, Rydberg series structures including several angular momentum components were formed within the Auger profile by the recapture of the photoelectrons into high-lying final ion orbitals. Our spectrum with resolution much narrower than the lifetime width of the corresponding core excited state allowed us to resolve detailed structures due to the orbital angular momenta very clearly. Unexpectedly, conjugate peaks originating from the exchange of angular momentum between the photoelectron and the Auger electron through Post-Collision-Interaction were found to dominate the spectrum. The new assignments were in accord with the quantum defect values obtained for the high Rydberg series for singly charged ionic Xe + 5 p(1S0) ml. This work was supported by Japan Society for the Promotion of Science through Grants-in-Aid for Scientific Research No. 23600009.

  16. Directional Auger electron spectroscopy (DAES) and directional elastic peak electron spectroscopy (DEPES) in the investigation of the crystalline structure of surface layers: the Ag/Cu(111) interface

    NASA Astrophysics Data System (ADS)

    Mróz, S.; Nowicki, M.

    1993-11-01

    Dependence of the Auger signal (directional Auger electron spectroscopy — DAES) and the elastically scattered electron intensity (directional elastic peak electron spectroscopy — DEPES) on the direction of the primary electron beam ( E = 600-1500 eV) was measured using a retarding field analyser (LEED optics) for the Cu(111) face, both clean and covered with silver up to 12 ML. Well-developed maxima of DAES and DEPES signals appear when the primary beam is parallel to one of the close-packed rows of atoms in the sample surface layer, while the angular distribution of the emitted electrons is averaged over the large acceptance angle of the RFA and does not influence appreciably the DAES and DEPES profiles. From the positions of the maxima mentioned above the atomic structure of a few surface layers can be determined. The silver layer was found to be rotated for 60° with respect to the Cu(111) substrate.

  17. Oxygen diffusion from anodic surface oxide films on titanium subhydride studies by auger electron spectroscopy and electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, P. S.; Wittberg, T. N.; Wolf, J. D.; Keil, R. G.

    TiH sub x (0.5 less than x less than 1.7) samples were prepared from titanium foil in order to study the diffusion of oxygen in the titanium subhydride. An anodic oxide, 1000A thick, was grown on the titanium subhydride foils in an agueous saturated solution of ammonium tetraborate. These anodized samples were then heat treated at temperatures between 500 and 600(0)C and changes in the profile of oxygen concentration as a function of depth were monitored using auger electron spectroscopy. From this data then it was possible to calculate the diffusivity of oxygen in the titanium subhydride. It was also found that electron energy loss spectroscopy could be used to determine the titanium subhydride stoichiometry in the near-surface region. This was done by measuring the energy of the bulk plasmon loss peak, which for TiH sub x, varies linearly with hydrogen content. The amount of dehydriding which occurred following a given heat treatment could be determined from profiles of the plasmon loss energy as a function of depth. A sample of anodized TiH0 87 was studied in some detail. Significant dehydriding of this sample for heat treatment times of less than one hour only occured at temperatures above 550(0)C.

  18. PCI and interference effects in the energy and angular correlation between the photoelectron and the Auger electron for equal electron energies

    NASA Astrophysics Data System (ADS)

    Sheinerman, S. A.; Schmidt, V.

    1997-04-01

    Photoionization in the inner shell of an atom followed by Auger decay is considered for the case of equal energies of the emitted electrons. Due to the indistinguishability of both electrons it is imperative to describe this process as resonance embedded in the double ionization continuum, i.e. within the one-step formulation. As a consequence, two amplitudes appear where either one of the two electrons with momenta 0953-4075/30/7/008/img1 and 0953-4075/30/7/008/img2 is connected to the photoprocess, and correspondingly the other to the Auger decay. We have accounted for the modification of these amplitudes by post-collision interaction (PCI). To elucidate our theoretical treatment we have selected a simple example and demonstrate how both exchange and PCI strongly modify by interference the energy- and angle-dependent correlation patterns of coincident two-electron emission.

  19. Development of an Apparatus for High-Resolution Auger Photoelectron Coincidence Spectroscopy (APECS) and Electron Ion Coincidence (EICO) Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kakiuchi, Takuhiro; Hashimoto, Shogo; Fujita, Narihiko; Mase, Kazuhiko; Tanaka, Masatoshi; Okusawa, Makoto

    We have developed an electron electron ion coincidence (EEICO) apparatus for high-resolution Auger photoelectron coincidence spectroscopy (APECS) and electron ion coincidence (EICO) spectroscopy. It consists of a coaxially symmetric mirror electron energy analyzer (ASMA), a miniature double-pass cylindrical mirror electron energy analyzer (DP-CMA), a miniature time-of-flight ion mass spectrometer (TOF-MS), a magnetic shield, an xyz stage, a tilt-adjustment mechanism, and a conflat flange with an outer diameter of 203 mm. A sample surface was irradiated by synchrotron radiation, and emitted electrons were energy-analyzed and detected by the ASMA and the DP-CMA, while desorbed ions were mass-analyzed and detected by the TOF-MS. The performance of the new EEICO analyzer was evaluated by measuring Si 2p photoelectron spectra of clean Si(001)-2×1 and Si(111)-7×7, and by measuring Si-L23VV-Si-2p Auger photoelectron coincidence spectra (Si-L23VV-Si-2p APECS) of clean Si(001)-2×1.

  20. Mechanical test in-situ fracture device for Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Moorhead, R. D.

    1975-01-01

    An in-situ fracture device for Auger spectroscopy was described. The device is designed to handle small tensile specimens or small double cantilever beam specimens and is fully instrumented with load and displacement transducers so that quantitative stress-strain measurements can be made directly. Some initial test results for specimens made from 4130 and 1020 steel were presented.

  1. Inner-shell ionization of rotating linear molecules in the presence of spin-dependent interactions: Entanglement between a photoelectron and an auger electron

    NASA Astrophysics Data System (ADS)

    Ghosh, R.; Chandra, N.; Parida, S.

    2009-03-01

    This paper reports results of a theoretical study of angle- and spin-resolved photo-Auger electron coincident spectroscopy in the form of entanglement between these two particles emitted from a linear molecule. First, we develop an expression for a density matrix needed for studying spin-entanglement between a photoelectron and an Auger electron. In order to properly represent the molecular symmetries, nuclear rotation, and the spin-dependent interactions (SDIs), we have used symmetry adapted wavefunctions in Hund’s coupling scheme (a) for all the species participating in this two-step process. This expression shows that spin-entanglement in a photo-Auger electron pair in the presence of SDIs very strongly depends upon, among other things, polarization of the ionizing radia- tion, directions of motion and of spin polarization of two ejected electrons, and the dynamics of photoionization and of Auger decay. We have applied this expression, as an example, to a generic linear molecule in its J0, M0 = 0 state. This model calculation clearly brings out the salient features of the spin-entanglement of a photo-Auger electron pair in the presence of the SDIs.

  2. Auger analysis of a fiber/matrix interface in a ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Honecy, Frank S.; Pepper, Stephen V.

    1988-01-01

    Auger electron spectroscopy (AES) depth profiling was used to characterize the fiber/matrix interface of an SiC fiber, reaction bonded Si3N4 matrix composite. Depth profiles of the as received double coated fiber revealed concentration oscillations which disappeared after annealing the fiber in the environment used to fabricate the composite. After the composite was fractured, the Auger depth profiles showed that failure occurred in neither the Beta-SiC fiber body nor in the Si3N4 matrix but, concurrently, at the fiber coating/matrix interface and within the fiber coating itself.

  3. Luminescence quenching of conductive Si nanocrystals via “Linkage emission”: Hopping-like propagation of infrared-excited Auger electrons

    SciTech Connect

    Ishii, Masashi; Crowe, Iain F.; Halsall, Matthew P.; Hamilton, Bruce; Knights, Andrew P.; Gwilliam, Russell M.

    2014-08-14

    Phosphorus (P) is an n-type dopant for conductive silicon nanocrystals (Si-nc's), the electrical activation of which may be monitored through a non-radiative Auger recombination process that quenches the Si-nc luminescence. We investigated this quenching mechanism through electrical measurements of Si-nc's. Infrared-excited Auger electron emission as the non-radiative process was directly probed and the dynamics of the process are determined from a frequency response analysis. To explain the dynamics, we propose a model in which Auger electrons with a low kinetic energy establish a local inter-nanocrystal conductance and the repetition of this local conductance results in a constant photocurrent (“linkage emission”). This emission becomes significant by electron filling in the Si-nc's owing to the electrical activation of P, which is consistent with observed luminescence quenching behavior. We found that the IR photo-excited emission is distinct from the thermally induced hopping conduction and show that confined, rather than trapped, charges are the source of the Auger electrons. Thus, the process consumes both confined charges and the recombination energy for Auger emission, which explains the luminescence quenching mechanism of Si-nc:P.

  4. AES XPS study of chromium carbides and chromium iron carbides

    NASA Astrophysics Data System (ADS)

    Detroye, M.; Reniers, F.; Buess-Herman, C.; Vereecken, J.

    1999-04-01

    The nature of chromium rich carbides which precipitate at grain boundaries in steels is still not perfectly understood. We performed a multitechnique approach on model chromium carbide and chromium-iron carbide samples: Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and High Energy Electron Diffraction (HEED) were used to characterise the samples. Significant chemical shifts were observed for the Cr, Fe and C XPS peaks in the M 7C 3 compound (M stands for metal), indicating unambiguously that the compound formed is a mixed iron-chromium carbide.

  5. Auger electron spectroscopy analysis of the first stages of thermally stimulated oxidation of GaAs(100)

    NASA Astrophysics Data System (ADS)

    Passeggi, M. C. G.; Vaquila, I.; Ferrón, J.

    1998-05-01

    The first stages (exposures <10 4 L) of thermally stimulated oxidation of GaAs(100) have been studied using Auger electron spectroscopy and principal component analysis. We compare the GaAs oxidation processes taking place at high (700 K) and room temperatures, and during simultaneous electron bombardment and oxygen exposure. We found that while at room temperature, GaAs oxidizes via a one-phase process involving the simultaneous oxidation of Ga and As, the high temperature process is characterized by the presence of two different GaAs oxide phases. The first phase involves the simultaneous oxidation of Ga and As while in the second, only Ga oxides are formed. On the other hand, under simultaneous oxygen exposure and electron irradiation, two different oxide phases appear, both of them exhibiting the same features of the room temperature process, i.e., the simultaneous oxidation of Ga and As.

  6. Auger electron nanoscale mapping and x-ray photoelectron spectroscopy combined with gas cluster ion beam sputtering to study an organic bulk heterojunction

    SciTech Connect

    Heon Kim, Seong; Heo, Sung; Ihn, Soo-Ghang; Yun, Sungyoung; Hwan Park, Jong; Chung, Yeonji; Lee, Eunha; Park, Gyeongsu; Yun, Dong-Jin

    2014-06-16

    The lateral and vertical distributions of organic p/n bulk heterojunctions for an organic solar cell device are, respectively, investigated using nanometer-scale Auger electron mapping and using X-ray photoelectron spectroscopy (XPS) with Ar gas cluster ion beam (GCIB) sputtering. The concentration of sulfur, present only in the p-type material, is traced to verify the distribution of p-type (donor) and n-type (acceptor) materials in the blended structure. In the vertical direction, a considerable change in atomic sulfur concentration is observed using XPS depth profiling with Ar GCIB sputtering. In addition, Auger electron mapping of sulfur reveals the lateral 2-dimensional distribution of p- and n-type materials. The combination of Auger electron mapping with Ar GCIB sputtering should thereby allow the construction of 3-dimensional distributions of p- and n-type materials in organic photovoltaic cells.

  7. X-Ray Lines Close to Kll Auger Electron Energies from Iron, Cobalt, Nickel, and Copper Monocrystals

    NASA Astrophysics Data System (ADS)

    Koo, Yeon Deog

    1990-01-01

    By x-ray bombardment of metal monocrystals (Fe, Co, Ni, and Cu), x-rays of KLL radiative Auger electrons (KLL RAE) can be observed on the low energy side of the Kalpha lines. The energies of the x-rays of the KLL RAE of each monocrystal are the same for different lattice planes and when different kinds of x-ray tubes (Mo, W, and Cu) are used. Therefore, the peak energies detected within the KLL Auger electron energy limit are interpreted as KLL RAE x-rays. The measured intensity ratios of KLL/Kalpha are about 0.3%. Additionally, the ratio of I(Kbeta )/I(Kalpha) and I(Si escape peak)/I(Kalpha) are measured. All of these values agree well with theoretical values. The beam shapes of KLL RAE x-rays are studied by taking pictures of x-ray films. The intensity distribution for Ni and Cu are measured by changing the crystal angle with respect to the incident x-ray beam near the Bragg angles of KLL RAE x-rays. It is shown that the KLL RAE x-rays are very sharp and stimulated when the crystal is set at the Bragg angle of the KLL RAE with respect to the incident beam, which contains both the pumping radiation and Bremsstrahlung of the frequencies in the KLL RAE range in which the KLL x-rays stimulation is achieved.

  8. Pointable Auger

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1985-01-01

    Machine drills, crushes, and feeds coal - and seeks out extra-hard inclusions. Auger mounted on gimbal, located at its center of gravity for ease of maneuvering. Opposing hydraulic cylinders cooperate to point auger under control of microprocessor. Its diamond teeth break up coal seam, it crushes coal fed to it by mining machine jaws, and its screw action pushes crushed coal into slurry-forming chamber.

  9. Determination of the solid angle and response function of a hemispherical spectrograph with injection lens for Auger electrons emitted from long lived projectile states

    SciTech Connect

    Doukas, S.; Madesis, I.; Dimitriou, A.; Zouros, T. J. M.; Laoutaris, A.; Benis, E. P.

    2015-04-15

    We present SIMION 8.1 Monte Carlo type simulations of the response function and detection solid angle for long lived Auger states (lifetime τ ∼ 10{sup −9} − 10{sup −5} s) recorded by a hemispherical spectrograph with injection lens and position sensitive detector used for high resolution Auger spectroscopy of ion beams. Also included in these simulations for the first time are kinematic effects particular to Auger emission from fast moving projectile ions such as line broadening and solid angle limitations allowing for a more accurate and realistic line shape modeling. Our results are found to be in excellent agreement with measured electron line shapes of both long lived 1s2s2p{sup 4}P and prompt Auger projectile states formed by electron capture in collisions of 25.3 MeV F{sup 7+} with H{sub 2} and 12.0 MeV C{sup 4+} with Ne recorded at 0{sup ∘} to the beam direction. These results are important for the accurate evaluation of the 1s2s2p {sup 4}P/{sup 2}P ratio of K-Auger cross sections whose observed non-statistical production by electron capture into He-like ions, recently a field of interesting interpretations, awaits further resolution.

  10. Monitoring Ultrafast Chemical Dynamics by Time-Domain X-ray Photo- and Auger-Electron Spectroscopy.

    PubMed

    Gessner, Oliver; Gühr, Markus

    2016-01-19

    The directed flow of charge and energy is at the heart of all chemical processes. Extraordinary efforts are underway to monitor and understand the concerted motion of electrons and nuclei with ever increasing spatial and temporal sensitivity. The element specificity, chemical sensitivity, and temporal resolution of ultrafast X-ray spectroscopy techniques hold great promise to provide new insight into the fundamental interactions underlying chemical dynamics in systems ranging from isolated molecules to application-like devices. Here, we focus on the potential of ultrafast X-ray spectroscopy techniques based on the detection of photo- and Auger electrons to provide new fundamental insight into photochemical processes of systems with various degrees of complexity. Isolated nucleobases provide an excellent testing ground for our most fundamental understanding of intramolecular coupling between electrons and nuclei beyond the traditionally applied Born-Oppenheimer approximation. Ultrafast electronic relaxation dynamics enabled by the breakdown of this approximation is the major component of the nucleobase photoprotection mechanisms. Transient X-ray induced Auger electron spectroscopy on photoexcited thymine molecules provides atomic-site specific details of the extremely efficient coupling that converts potentially bond changing ultraviolet photon energy into benign heat. In particular, the time-dependent spectral shift of a specific Auger band is sensitive to the length of a single bond within the molecule. The X-ray induced Auger transients show evidence for an electronic transition out of the initially excited state within only ∼200 fs in contrast to theoretically predicted picosecond population trapping behind a reaction barrier. Photoinduced charge transfer dynamics between transition metal complexes and semiconductor nanostructures are of central importance for many emerging energy and climate relevant technologies. Numerous demonstrations of photovoltaic and

  11. Analytical Chemistry of Surfaces: Part II. Electron Spectroscopy.

    ERIC Educational Resources Information Center

    Hercules, David M.; Hercules, Shirley H.

    1984-01-01

    Discusses two surface techniques: X-ray photoelectron spectroscopy (ESCA) and Auger electron spectroscopy (AES). Focuses on fundamental aspects of each technique, important features of instrumentation, and some examples of how ESCA and AES have been applied to analytical surface problems. (JN)

  12. Electron Beam Damage in Poly(Vinyl Chloride) and Poly(Acrylonitrile) as Observed by Auger Electron Spectroscopy

    SciTech Connect

    Lea, Alan S.; Engelhard, Mark H.; Baer, Donald R.

    2003-03-07

    AES spectra of spun-cast films of poly(vinyl chloride) (PVC) and poly(acrylonitrile) (PAN) were collected over a period of time to determine specimen damage during exposure to a 10kV electron beam. For the PVC, loss of chlorine was observed over a period of 203 minutes to the extent that the final chlorine concentration was only 20% of its original value. PAN exhibited a loss in nitrogen content over a period of 120 minutes, but the rate of damage to the polymer was significantly less than PVC. Figure 1 shows the atomic concentration in the PVC film as a function of dose (time). It takes a dose of approximately 7.0x10-5 Ccm-5 for the chlorine concentration to fall from its original value by 10% (one definition of critical dose). Figure 2 shows a similar drop in nitrogen concentration in the PAN film as a function of dose. For this polymer, it takes a dose of 1.3x10-3 Ccm-2 for the nitrogen concentration to fall by 10%.

  13. Desorption due to Recoil Induced by Neutrino Emission and Auger Relaxation of CHLORINE-37 Following the Electron Capture Decay of ARGON-37.

    NASA Astrophysics Data System (ADS)

    Zhu, Lin

    1995-01-01

    A novel experiment was developed in this work to study the desorption and the Auger relaxation processes of ^{37}Cl following the ^{37}Ar electron capture decay. For the first time, the desorption of ^{37}Cl ions due to recoil induced by neutrino emission in this decay process was observed. The kinetic energy distribution of the desorbing ^{37}Cl ions was accurately measured by using coincidence techniques. The resulting ^{37}Cl ion energy ranges from 5 eV to 13 eV with a maximum at around 9 eV and an FWHM about 3 eV. The charge state distribution of the desorbing ^{37}Cl ions was also measured. The resulting charge state distribution is: 53% of the total ions have charge +e, 21% have charge +2e and 26% have charge +ne, where n >= 3. The desorbing probability of ^ {37}Cl ions was measured by two independent experiments which gave the result of 9.4+/-1.2 %. The energy distribution, the charge state distribution and the desorbing probability of ^{37}Cl ions are all quite different as compared with the expected values for an isolated Cl atom. These differences are explained in the desorption model involving charge exchange and Coulomb repulsion between ^{37}Cl ions and their surrounding atoms. The electron capture decay also creates a highly unusual initial state in the ^{37 }Cl atom which allows direct observation of some novel relaxation processes which are amenable to many body theory, but essentially impossible to probe experimentally with conventional techniques. For the first time, direct evidence of the double Auger decay of a K-hole and the large shift in energy (22 eV) of an LMM Auger line was reported. The double Auger decay probability and energy distribution of the two double Auger electrons were measured by using coincidence techniques. The resulting double Auger decay probability ranges from 12+/-0.3 % to 15+/-0.4% of the total Auger decay. The preferred energy distribution of the double Auger emission is for one of the electrons to take most of the

  14. Local atomic configuration and Auger Valence Electron Spectra in BiSrCaCuO single crystals

    SciTech Connect

    Fujiwara, Y.; Hirata, S.; Nishikubo, M.; Kobayashi, T. ); Nakayama, H.; Fujita, H. . Faculty of Engineering)

    1991-03-01

    This paper reports on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (2212) and Ca-doped Bi{sub 2}Sr{sub 2}CuO{sub y} (2201) single crystals systematically investigated by Auger Valence Electron Spectroscopy (AVES). In AVES measurements on two kinds of crystals, a drastic difference was observed in the spectral shape of Ca(2p,3p,3p), reflecting a difference in spin-orbit splitting induced by local atomic configuration in the vicinity of Ca atoms. Furthermore, Ca(2p,3p,4s) spectrum appeared in both the crystals, which indicates that the real valency of Ca atoms is deviated from + 2 in the crystals. These results suggest that AVES is a promising probe for characterizing local atomic configuration and valence electron states of the constituent elements.

  15. Electronic Doppler effect in resonant Auger decay of CO molecules upon excitation near a shake-up {pi} resonance

    SciTech Connect

    Sorensen, S. L.; Kitajima, M.; Tanaka, T.; Hoshino, M.; Tanaka, H.; Tamenori, Y.; Sankari, R.; Piancastelli, M. N.; Ueda, K.; Velkov, Y.; Minkov, I.; Carravetta, V. |; Gel'mukhanov, F. |

    2007-12-15

    We present an experimental observation of the electronic Doppler effect in resonant Auger spectra upon core excitation slightly above the carbon K edge of the CO molecule. Thus the electronic Doppler effect has been identified in above-threshold excitation, and in a transition of {pi} symmetry. Ab initio calculations of the potential energy curves of the relevant states of CO and the wave packet technique have been employed to provide a theoretical background to the experimental studies. The weak feature around 299.4 eV in the photoabsorption spectrum, whose decay has been investigated by the present experiment, is assigned to double (core-valence) excitations to C 1s shake-up states |1s{sub C}{sup -1}1{pi}{sup -1}{pi}*{sup 2}> with a strong dissociative character, and the Doppler splitting of the atomic peak has been reproduced by the simulation.

  16. Auger-electron angular distributions calculated without the two-step approximation: Calculation of angle-resolved resonant Auger spectra of C{sub 2}H{sub 2}

    SciTech Connect

    Colle, Renato; Embriaco, Davide; Massini, Michol; Simonucci, Stefano; Taioli, Simone

    2004-10-01

    Analytic expressions for the direct, resonant, and interference contributions to the differential cross section of a resonant Auger process, produced by the inner-shell photoionization of a linear molecule either 'fixed in space' or belonging to a gas of randomly oriented molecules, have been derived following Dill's procedures [Dill et al., Phys. Rev. Lett. 45, 1393 (1980)], but going beyond the two-step approximation. Angle-resolved Auger spectra of the C{sub 2}H{sub 2} molecule measured on top of the C 1s{yields}{pi}* resonance [Kivimaeki et al., J. Phys. B 30, 4279 (1997)] have been calculated together with asymmetry parameters, analyzing also the different contributions to the electron angular distributions.

  17. Low energy electron microscopy and Auger electron spectroscopy studies of Cs-O activation layer on p-type GaAs photocathode

    NASA Astrophysics Data System (ADS)

    Jin, Xiuguang; Cotta, Alexandre A. C.; Chen, Gong; N`Diaye, Alpha T.; Schmid, Andreas K.; Yamamoto, Naoto

    2014-11-01

    Work function, photoemission yield, and Auger electron spectra were measured on (001) p-type GaAs during negative electron affinity (NEA) surface preparation, surface degradation, and heating processes. The emission current sensitively depends on work function change and its dependence allows us to determine that the shape of the vacuum barrier was close to double triangular. Regarding the NEA surface degradation during photoemission, we discuss the importance of residual gas components the oxygen and hydrogen. We also found that gentle annealing (≤100 °C) of aged photocathodes results in a lower work function and may offer a patch to reverse the performance degradation.

  18. Synthesis, Crystal and Electronic Structures of the Pnictides AE3TrPn3 (AE = Sr, Ba; Tr = Al, Ga; Pn = P, As)

    DOE PAGESBeta

    Stoyko, Stanislav; Voss, Leonard; He, Hua; Bobev, Svilen

    2015-09-24

    New ternary arsenides AE3TrAs3 (AE = Sr, Ba; Tr = Al, Ga) and their phosphide analogs Sr3GaP3 and Ba3AlP3 have been prepared by reactions of the respective elements at high temperatures. Single-crystal X-ray diffraction studies reveal that Sr3AlAs3 and Ba3AlAs3 adopt the Ba3AlSb3-type structure (Pearson symbol oC56, space group Cmce, Z = 8). This structure is also realized for Sr3GaP3 and Ba3AlP3. Likewise, the compounds Sr3GaAs3 and Ba3GaAs3 crystallize with the Ba3GaSb3-type structure (Pearson symbol oP56, space group Pnma, Z = 8). Both structures are made up of isolated pairs of edge-shared AlPn4 and GaPn4 tetrahedra (Pn = pnictogen, i.e.,more » P or As), separated by the alkaline-earth Sr2+ and Ba2+ cations. In both cases, there are no homoatomic bonds, hence, regardless of the slightly different atomic arrangements, both structures can be rationalized as valence-precise [AE2+]3[Tr3+][Pn3-]3, or rather [AE2+]6[Tr2Pn6]12-, i.e., as Zintl phases.« less

  19. Oxygen diffusion from anodic surface oxide films on titanium subhydride studied by auger electron spectroscopy and electron energy loss spectroscopy

    SciTech Connect

    Wang, P.S.; Wittberg, T.N.; Wolf, J.D.; Keil, R.G.

    1984-01-01

    In the present study, TiH/sub x/ (0.5 < x < 1.7) samples were prepared from titanium foil in order to study the diffusion of oxygen in the titanium subhydride. An anodic oxide, 1000A thick, was grown on the titanium subhydride foils in an aqueous saturated solution of ammonium tetraborate. These anodized samples were then heat treated at temperatures between 500 and 600/sup 0/C and changes in the profile of oxygen concentration as a function of depth were monitored using AES. From this data then it was possible to calculate the diffusivity of oxygen in the titanium subhydride. It was also found that electron energy loss spectroscopy (EELS) could be used to determine the titanium subhydride stoichiometry in the near-surface region. This was done by measuring the energy of the bulk plasmon loss peak, which for TiH/sub x/, varies linearly with hydrogen content. The amount of dehydriding which had occurred following a given heat treatment could be determined from profiles of the plasmon loss energy as a function of depth. A sample of anodized TiH/sub 0/ /sub 87/ was studied in some detail. Significant dehydriding of this sample for heat treatment times of less than one hour, only occurred at temperatures above 550/sup 0/C. Likewise, oxide dissolution was only significant at temperatures greater than 550/sup 0/C. In general, for the heat treatment parameters which were chosen, the diffusivity of oxygen in TiH/sub 0/ /sub 87/ was about an order of magnitude lower than that for oxygen in titanium.

  20. Deviations from one-electron behavior in the Ag and Pd M4,5-VV Auger spectra of AgcPd1-c alloys

    NASA Astrophysics Data System (ADS)

    Mariot, J.-M.; Hague, C. F.; Dufour, G.

    1981-04-01

    A systematic investigation of the Ag and Pd M4,5-VV Auger spectra in the pure metals and in the AgcPd1-c(0.1<=c<=0.9) alloys is presented. The shape of the Auger spectra is discussed in relation to the values of the effective Coulomb interaction Ueff between the two holes present in the final state of the Auger transition and of the width W of the one-electron local densities of states as obtained from Lβ2,15 soft-x-ray emission bands. The Auger spectra of Ag in the metal and the alloys have a pronounced quasiatomic character, as can be expected from the Ueff2W ratio which is found to be close to unity. The Auger spectrum of pure Pd (Ueff2W~0.4) can be explained in terms of an atomic model in which strong band effects are present. For alloys with low-Pd content where Pd forms an impurity state, it is shown that final states other than the localized [4d2] two-hole state have to be invoked to explain the line shape.

  1. AE 941.

    PubMed

    2004-01-01

    AE 941 [Arthrovas, Neoretna, Psovascar] is shark cartilage extract that inhibits angiogenesis. AE 941 acts by blocking the two main pathways that contribute to the process of angiogenesis, matrix metalloproteases and the vascular endothelial growth factor signalling pathway. When initial development of AE 941 was being conducted, AEterna assigned the various indications different trademarks. Neovastat was used for oncology, Psovascar was used for dermatology, Neoretna was used for ophthalmology and Arthrovas was used for rheumatology. However, it is unclear if these trademarks will be used in the future and AEterna appears to only be using the Neovastat trademark in its current publications regardless of the indication. AEterna Laboratories signed commercialisation agreements with Grupo Ferrer Internacional SA of Spain and Medac GmbH of Germany in February 2001. Under the terms of the agreement, AEterna has granted exclusive commercialisation and distribution rights to AE 941 in oncology to Grupo Ferrer Internacional for the Southern European countries of France, Belgium, Spain, Greece, Portugal and Italy. It also has rights in Central and South America. Medac GmbH will have marketing rights in Germany, the UK, Scandinavia, Switzerland, Austria, Ireland, the Netherlands and Eastern Europe. In October 2002, AEterna Laboratories announced that it had signed an agreement with Australian healthcare products and services company Mayne Group for marketing AE 941 (as Neovastat) in Australia, New Zealand, Canada and Mexico. In March 2003, AEterna Laboratories announced it has signed an agreement with Korean based LG Life Sciences Ltd for marketing AE 941 (as Neovastat) in South Korea. The agreement provides AEterna with upfront and milestone payments, as well as a return on manufacturing and sales of AE 941. AEterna Laboratories had granted Alcon Laboratories an exclusive worldwide licence for AE 941 for ophthalmic products. However, this licence has been terminated. In

  2. Electronic state-lifetime interference in resonant Auger spectra: a tool to disentangle overlapping core-excited states.

    PubMed

    Goldsztejn, Gildas; Marchenko, Tatiana; Céolin, Denis; Journel, Loïc; Guillemin, Renaud; Rueff, Jean-Pascal; Kushawaha, Rajesh K; Püttner, Ralph; Piancastelli, Maria Novella; Simon, Marc

    2016-06-01

    We have measured resonant-Auger decay following Cl 1s(-1) excitations in HCl and CH3Cl molecules, and extracted the pseudo-cross sections of different Cl 2p(-2) final states. These cross sections show clear evidence of shake processes as well as contributions of electronic state-lifetime interference (ELI). To describe the spectra we developed a fit approach that takes into account ELI contributions and ultrafast nuclear dynamics in dissociative core-excited states. Using this approach we utilized the ELI contributions to obtain the intensity ratios of the overlapping states Cl 1s(-1)4pπ/1s(-1)4pσ in HCl and Cl 1s(-1)4pe/1s(-1)4pa1 in CH3Cl. The experimental value for HCl is compared with theoretical results showing satisfactory agreement. PMID:27199185

  3. Thermal effects in equilibrium surface segregation in a copper/10-atomic-percent-aluminum alloy using Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Ferrante, J.

    1972-01-01

    Equilibrium surface segregation of aluminum in a copper-10-atomic-percent-aluminum single crystal alloy oriented in the /111/ direction was demonstrated by using Auger electron spectroscopy. This crystal was in the solid solution range of composition. Equilibrium surface segregation was verified by observing that the aluminum surface concentration varied reversibly with temperature in the range 550 to 850 K. These results were curve fitted to an expression for equilibrium grain boundary segregation and gave a retrieval energy of 5780 J/mole (1380 cal/mole) and a maximum frozen-in surface coverage three times the bulk layer concentration. Analyses concerning the relative merits of sputtering calibration and the effects of evaporation are also included.

  4. Auger electron spectroscopy study of oxidation of a PdCr alloy used for high-temperature sensors

    NASA Technical Reports Server (NTRS)

    Boyd, Darwin L.; Zeller, Mary V.; Vargas-Aburto, Carlos

    1993-01-01

    A Pd-13 wt. percent Cr solid solution is a promising high-temperature strain gage alloy. In bulk form it has a number of properties that are desirable in a resistance strain gage material, such as a linear electrical resistance versus temperature curve to 1000 C and stable electrical resistance in air at 1000 C. However, unprotected fine wire gages fabricated from this alloy perform well only to 600 C. At higher temperatures severe oxidation degrades their electrical performance. In this work Auger electron spectroscopy was used to study the oxidation chemistry of the alloy wires and ribbons. Results indicate that the oxidation is caused by a complex mechanism that is not yet fully understood. As expected, during oxidation, a layer of chromium oxide is formed. This layer, however, forms beneath a layer of metallic palladium. The results of this study have increased the understanding of the oxidation mechanism of Pd-13 wt. percent Cr.

  5. Auger electron spectroscopy study and depth profile analyses of the CaS:Eu2+ pulsed laser deposited thin luminescent films

    NASA Astrophysics Data System (ADS)

    Nyenge, R. L.; Swart, H. C.; Ntwaeaborwa, O. M.

    2016-06-01

    This paper presents the results of a study of the chemical composition, depth profile analyses of pulsed laser deposited CaS:Eu2+ thin films grown at different substrate temperatures. Using Auger electron spectroscopy, we have shown that the thin film grown in an argon atmosphere shows sulfur deficiency as the substrate temperature is increased from 200 to 650 °C.

  6. Growth and structure of rapid thermal silicon oxides and nitroxides studied by spectroellipsometry and Auger electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Gonon, N.; Gagnaire, A.; Barbier, D.; Glachant, A.

    1994-11-01

    Rapid thermal oxidation of Czochralski-grown silicon in either O2 or N2O atmospheres have been studied using spectroellipsometry and Auger electron spectroscopy. Multiwavelength ellipsometric data were processed in order to separately derive the thickness and refractive indexes of rapid thermal dielectrics. Results revealed a significant increase of the mean refractive index as the film thickness falls below 20 nm for both O2 or N2O oxidant species. A multilayer structure including an about 0.3-nm-thick interfacial region of either SiO(x) or nitroxide in the case of O2 and N2O growth, respectively, followed by a densified SiO2 layer, was found to accurately fit the experimental data. The interfacial region together with the densified state of SiO2 close to the interface suggest a dielectric structure in agreement with the continuous random network model proposed for classical thermal oxides. Auger electron spectroscopy analysis confirmed the presence of noncrystalline Si-Si bonds in the interfacial region, mostly in the case of thin oxides grown in O2. It was speculated that the initial fast growth regime was due to a transient oxygen supersaturation in the interfacial region. Besides, the self-limiting growth in N2O was confirmed and explained in agreement with several recently published data, by the early formation of a very thin nitride or oxynitride membrane in the highly densified oxide beneath the interface. The beneficial effect of direct nitrogen incorporation by rapid thermal oxidation in N2O instead of O2 for the electrical behavior of metal-oxide-semiconductor capacitors is likely a better SiO2/Si lattice accommodation through the reduction of stresses and Si-Si bonds in the interfacial region of the dielectric.

  7. Synthesis, Crystal and Electronic Structures of the Pnictides AE3TrPn3 (AE = Sr, Ba; Tr = Al, Ga; Pn = P, As)

    SciTech Connect

    Stoyko, Stanislav; Voss, Leonard; He, Hua; Bobev, Svilen

    2015-09-24

    New ternary arsenides AE3TrAs3 (AE = Sr, Ba; Tr = Al, Ga) and their phosphide analogs Sr3GaP3 and Ba3AlP3 have been prepared by reactions of the respective elements at high temperatures. Single-crystal X-ray diffraction studies reveal that Sr3AlAs3 and Ba3AlAs3 adopt the Ba3AlSb3-type structure (Pearson symbol oC56, space group Cmce, Z = 8). This structure is also realized for Sr3GaP3 and Ba3AlP3. Likewise, the compounds Sr3GaAs3 and Ba3GaAs3 crystallize with the Ba3GaSb3-type structure (Pearson symbol oP56, space group Pnma, Z = 8). Both structures are made up of isolated pairs of edge-shared AlPn4 and GaPn4 tetrahedra (Pn = pnictogen, i.e., P or As), separated by the alkaline-earth Sr2+ and Ba2+ cations. In both cases, there are no homoatomic bonds, hence, regardless of the slightly different atomic arrangements, both structures can be rationalized as valence-precise [AE2+]3[Tr3+][Pn3-]3, or rather [AE2+]6[Tr2Pn6]12-, i.e., as Zintl phases.

  8. Density of Trap States and Auger-mediated Electron Trapping in CdTe Quantum-Dot Solids.

    PubMed

    Boehme, Simon C; Azpiroz, Jon Mikel; Aulin, Yaroslav V; Grozema, Ferdinand C; Vanmaekelbergh, Daniël; Siebbeles, Laurens D A; Infante, Ivan; Houtepen, Arjan J

    2015-05-13

    Charge trapping is an ubiquitous process in colloidal quantum-dot solids and a major limitation to the efficiency of quantum dot based devices such as solar cells, LEDs, and thermoelectrics. Although empirical approaches led to a reduction of trapping and thereby efficiency enhancements, the exact chemical nature of the trapping mechanism remains largely unidentified. In this study, we determine the density of trap states in CdTe quantum-dot solids both experimentally, using a combination of electrochemical control of the Fermi level with ultrafast transient absorption and time-resolved photoluminescence spectroscopy, and theoretically, via density functional theory calculations. We find a high density of very efficient electron traps centered ∼0.42 eV above the valence band. Electrochemical filling of these traps increases the electron lifetime and the photoluminescence quantum yield by more than an order of magnitude. The trapping rate constant for holes is an order of magnitude lower that for electrons. These observations can be explained by Auger-mediated electron trapping. From density functional theory calculations we infer that the traps are formed by dicoordinated Te atoms at the quantum dot surface. The combination of our unique experimental determination of the density of trap states with the theoretical modeling of the quantum dot surface allows us to identify the trapping mechanism and chemical reaction at play during charge trapping in these quantum dots. PMID:25853555

  9. AES study of ion-nitrided Fe-Mo and Fe-Mo-P P/M alloys

    SciTech Connect

    Molinari, A.; Straffelini, G.; Marchetti, F.

    1995-09-15

    In the present paper, the role of phosphorus in the microstructural transformations occurring during plasma nitriding of the Fe-Mo-P alloy is investigated and discussed. Auger Electron Spectroscopy (AES) measurements were carried out on the nitrided specimens. In fact, this technique has a good spatial resolution and nitrogen sensitivity and the line shape analysis represents a powerful tool for determining the chemical environment in which the emitting element is found. In this respect, a detailed study of the line shape of the nitrogen Auger transition was shown to be a powerful method to gain information on the nitrides precipitated in the surface layers.

  10. Development of a miniature double-pass cylindrical mirror electron energy analyzer (DPCMA), and its application to Auger photoelectron coincidence spectroscopy (APECS)

    NASA Astrophysics Data System (ADS)

    Kobayashi, Eiichi; Seo, Junya; Nambu, Akira; Mase, Kazuhiko

    2007-09-01

    We have developed a miniature double-pass cylindrical mirror electron energy analyzer (DPCMA) with an outer diameter of 26 mm. The DPCMA consists of a shield for the electric field, inner and outer cylinders, two pinholes with a diameter of 2.0 mm, and an electron multiplier. By assembling the DPCMA in a coaxially symmetric mirror electron energy analyzer (ASMA) coaxially and confocally we developed an analyzer for Auger photoelectron coincidence spectroscopy (APECS). The performance was estimated by measuring the Si-LVV-Auger Si-1s-photoelectron coincidence spectra of clean Si(1 1 1). The electron-energy resolution of the DPCMA was estimated to be E/Δ E = 20. This value is better than that of the miniature single-pass CMA ( E/Δ E = 12) that was used in the previous APECS analyzer.

  11. Phase-Space Density Analysis of the AE-8 Traped Electron and the AP-8 Trapped Proton Model Environments

    SciTech Connect

    Thomas E. Cayton

    2005-08-01

    The AE-8 trapped electron and the AP-8 trapped proton models are used to examine the L-shell variation of phase-space densities for sets of transverse (or 1st) invariants, {mu}, and geometrical invariants, K (related to the first two adiabatic invariants). The motivation for this study is twofold: first, to discover the functional dependence of the phase-space density upon the invariants; and, second, to explore the global structure of the radiation belts within this context. Variation due to particle rest mass is considered as well. The overall goal of this work is to provide a framework for analyzing energetic particle data collected by instruments on Global Positioning System (GPS) spacecraft that fly through the most intense region of the radiation belt. For all considered values of {mu} and K, and for 3.5 R{sub E} < L < 6.5 R{sub E}, the AE-8 electron phase-space density increases with increasing L; this trend--the expected one for a population diffusing inward from an external source--continues to L = 7.5 R{sub E} for both small and large values of K but reverses slightly for intermediate values of K. The AP-8 proton phase-space density exhibits {mu}-dependent local minima around L = 5 R{sub E}. Both AE-8 and AP-8 exhibit critical or cutoff values for the invariants beyond which the flux and therefore the phase-space density vanish. For both electrons and protons, these cutoff values vary systematically with magnetic moment and L-shell and are smaller than those estimated for the atmospheric loss cone. For large magnetic moments, for both electrons and protons, the K-dependence of the phase-space density is exponential, with maxima at the magnetic equator (K = 0) and vanishing beyond a cutoff value, K{sub c}. Such features suggest that momentum-dependent trapping boundaries, perhaps drift-type loss cones, serve as boundary conditions for trapped electrons as well as trapped protons.

  12. Phase-Space Density Analyses of the AE-8 Trapped Electron and the AP-8 Trapped Proton Model Environments

    SciTech Connect

    T.E. Cayton

    2005-08-12

    The AE-8 trapped electron and the AP-8 trapped proton models are used to examine the L-shell variation of phase-space densities for sets of transverse (or 1st) invariants, {mu}, and geometrical invariants, K (related to the first two adiabatic invariants). The motivation for this study is twofold: first, to discover the functional dependence of the phase-space density upon the invariants; and, second, to explore the global structure of the radiation belts within this context. Variation due to particle rest mass is considered as well. The overall goal of this work is to provide a framework for analyzing energetic particle data collected by instruments on Global Positioning System (GPS) spacecraft that fly through the most intense region of the radiation belt. For all considered values of {mu} and K, and for 3.5 R{sub E} < L < 6.5 R{sub E}, the AE-8 electron phase-space density increases with increasing L; this trend--the expected one for a population diffusing inward from an external source--continues to L = 7.5 R{sub E} for both small and large values of K but reverses slightly for intermediate values of K. The AP-8 proton phase-space density exhibits {mu}-dependent local minima around L = 5 R{sub E}. Both AE-8 and AP-8 exhibit critical or cutoff values for the invariants beyond which the flux and therefore the phase-space density vanish. For both electrons and protons, these cutoff values vary systematically with magnetic moment and L-shell and are smaller than those estimated for the atmospheric loss cone. For large magnetic moments, for both electrons and protons, the K-dependence of the phase-space density is exponential, with maxima at the magnetic equator (K = 0) and vanishing beyond a cutoff value, K{sub c}. Such features suggest that momentum-dependent trapping boundaries, perhaps drift-type loss cones, serve as boundary conditions for trapped electrons as well as trapped protons.

  13. On the correlation of the Auger generated hot electron emission and efficiency droop in III-N light-emitting diodes

    SciTech Connect

    Sadi, Toufik; Kivisaari, Pyry; Oksanen, Jani; Tulkki, Jukka

    2014-09-01

    Recent experiments presented in by Iveland et al. [Phys. Rev. Lett. 110, 177406 (2013)] demonstrated that hot electron emission from cesiated p-contacts of III-nitride quantum-well (QW) light-emitting diodes (LEDs) coincides with the onset of the efficiency droop. We have carried out Monte Carlo simulations of hot-electron transport in realistic III-N LEDs. The simulations account for the hole population and all relevant electron scattering and recombination processes. We show that Auger recombination generates a significant hot electron population, which is temporarily trapped in the conduction band side-valleys, without decaying completely before reaching the p-contact. The leakage current due to electron overflow and thermal escape from the QWs is shown to have a minimal impact on the droop. We conclude that the experimentally observed hot electrons are created by Auger recombination in QWs, and that the Auger effect as the origin of the droop is the only consistent explanation for the experimental findings of Iveland et al., [Phys. Rev. Lett. 110, 177406 (2013)].

  14. AMIGA at the Pierre Auger Observatory: The interface and control electronics of the first prototype muon counters

    NASA Astrophysics Data System (ADS)

    Videla, M.; Platino, M.; García, B.; Almela, A.; de la Vega, G.; Lucero, A.; Suarez, F.; Wainberg, O.; Sanchez, F.; Yelos, D.

    2015-08-01

    AMIGA is an enhancement of the Pierre Auger Observatory. The main goals of AMIGA are to extend the full efficiency range to lower energies of the Observatory and to measure the muon content of extensive air showers. Currently, it consists of 61 detector pairs, each one composed of a surface water-Cherenkov detector and a buried muon counter. Prototypes of the muon counter - buried at a depth of 2.25 m - were installed at each vertex of a hexagon and at its center with 750 m spacing. Each prototype has a detection area of 10 m2 segmented in 64 scintillation strips and coupled to a multi-anode PMT through optical fibers. The electronic systems of these prototypes are accessible via a service tube. An electronics interface and control board were designed to extract the data from the counter and to provide a remote control of the system. This article presents the design of the interface and control board and the results and performance during the first AMIGA acquisition period in 2012.

  15. Oxidation of metals and alloys in controlled atmospheres using in situ transmission electron microscopy and Auger spectrography

    NASA Technical Reports Server (NTRS)

    Rao, D. B.; Heinemann, K.; Douglass, D. L.

    1976-01-01

    Single-crystalline thin films of copper were oxidized at an isothermal temperature of 425 C and at an oxygen partial pressure of .005 Torr in situ in a high-resolution electron microscope. The specimens were prepared by epitaxial vapor deposition onto polished 100 and 110 faces of rocksalt and mounted in a hot stage inside an ultra-high-vacuum specimen chamber of the microscope. Large amounts of sulfur, carbon, and oxygen were detected by Auger electron spectroscopy on the surface of the as-received films and were removed in situ by ion-sputter etching immediately prior to the oxidation. The nucleation and growth characteristics of Cu2O on Cu were studied. Results show that neither stacking faults nor dislocations are associated with the Cu2O nucleation sites. The growth of Cu2O nuclei is linear with time. The experimental findings, including results from oxygen dissolution experiments and from repetitive oxidation-reduction-oxidation sequences, fit well into the framework of an oxidation process involving (a) the formation of a surface-charge layer, (b) oxygen saturation in the metal and (c) nucleation, followed by surface diffusion of oxygen and bulk diffusion of copper for lateral and vertical oxide growth, respectively.

  16. The effect of Sr and Bi on the Si(100) surface oxidation - Auger electron spectroscopy, low energy electron diffraction, and X-ray photoelectron spectroscopy study

    NASA Technical Reports Server (NTRS)

    Fan, W. C.; Mesarwi, A.; Ignatiev, A.

    1990-01-01

    The effect of Sr and Bi on the oxidation of the Si(100) surface has been studied by Auger electron spectroscopy, low electron diffraction, and X-ray photoelectron spectroscopy. A dramatic enhancement, by a factor of 10, of the Si oxidation has been observed for Si(100) with a Sr overlayer. The SR-enhanced Si oxidation has been studied as a function of O2 exposure and Sr coverage. In contrast to the oxidation promotion of Sr on Si, it has been also observed that a Bi overlayer on Si(100) reduced Si oxidation significantly. Sr adsorption on the Si(100) with a Bi overlayer enhances Si oxidation only at Sr coverage of greater than 0.3 ML.

  17. Production, PET performance and dosimetric considerations of 134Ce/134La, an Auger electron and positron-emitting generator for radionuclide therapy

    NASA Astrophysics Data System (ADS)

    Lubberink, Mark; Lundqvist, Hans; Tolmachev, Vladimir

    2002-02-01

    We propose the use of the Auger electron and positron-emitting generator 134Ce/134La (half-lives 3.16 d and 6.45 min) for radionuclide therapy. It combines emission of high-energy beta particles with Auger electrons. The high-energy beta particles have similar energies as those emitted by 90Y. Many cancer patients receiving radionuclide therapy have both bulk tumours, which are best treated with high-energy beta particles, and single spread cells or micrometastasis, which are preferably treated with low-energy electrons such as Auger and conversion electrons. Furthermore, the positron-emitting 134La can be used to study kinetics and dosimetry using PET. Production and PET performance were investigated and theoretical dosimetry calculations were made. PET resolution, recovery and quantitative accuracy were slightly degraded for 134La compared to 18F. 134Ce/134La absorbed doses to single cells were higher than absorbed doses from 90Y and 111In. Absorbed doses to spheres representing bulk tumours were almost as high as for 90Y, and a factor 10 higher than for 111In. Whole-body absorbed doses, based on kinetics of the somatostatin analogue octreotide, were higher for 134Ce/134La than for 90Y because of the 134La annihilation photons. This initial study of the therapeutic possibilities of 134Ce/134La is encouraging and justifies further investigations.

  18. Dosimetry at the sub-cellular scale of Auger-electron emitter 99mTc in a mouse single thyroid follicle.

    PubMed

    Taborda, A; Benabdallah, N; Desbrée, A

    2016-02-01

    The Auger-electrons emitted by (99m)Tc have been recently associated with the induction of thyroid stunning in in vivo experiments in mice, making the dosimetry at the sub-cellular level of (99m)Tc a pertinent and pressing subject. The S-values for (99m)Tc were calculated using MCNP6, which was first validated for studies at the sub-cellular scale and for low energies electrons. The calculation was then performed for (99m)Tc within different cellular compartments in a single mouse thyroid follicle model, considering the radiative and non-radiative transitions of the (99m)Tc radiation spectrum. It was shown that the contribution of the (99m)Tc Auger and low energy electrons to the absorbed dose to the follicular cells' nucleus is important, being at least of the same order of magnitude compared to the emitted photons' contribution and cannot be neglected. The results suggest that Auger-electrons emitted by (99m)Tc play a significant role in the occurrence of the thyroid stunning effect in mice. PMID:26704702

  19. Auger resonant Raman spectroscopy

    SciTech Connect

    Azuma, Y.; LeBrun, T.; MacDonald, M.; Southworth, S.H.

    1995-08-01

    As noted above, traditional spectroscopy of the electronic structure of the inner shells of atoms, molecules, and solids is limited by the lifetime broadening of the core-excited states. This limitation can also be avoided with the non-radiative analog of X-ray Raman scattering - resonant Auger Raman spectroscopy. We have used this technique to study the K-shell excitation spectrum of argon as the photon energy is continuously scanned across threshold.

  20. Dependence of Cell Survival on Iododeoxyuridine Concentration in 35-keV Photon-Activated Auger Electron Radiotherapy

    SciTech Connect

    Dugas, Joseph P.; Varnes, Marie E.; Sajo, Erno; Welch, Christopher E.; Ham, Kyungmin; Hogstrom, Kenneth R.

    2011-01-01

    Purpose: To measure and compare Chinese hamster ovary cell survival curves using monochromatic 35-keV photons and 4-MV x-rays as a function of concentration of the radiosensitizer iododeoxyuridine (IUdR). Methods and Materials: IUdR was incorporated into Chinese hamster ovary cell DNA at 16.6 {+-} 1.9%, 12.0 {+-} 1.4%, and 9.2 {+-} 1.3% thymidine replacement. Cells were irradiated from 1 to 8 Gy with 35-keV synchrotron-generated photons and conventional radiotherapy 4-MV x-rays. The effects of the radiation were measured via clonogenic survival assays. Surviving fraction was plotted vs. dose and fit to a linear quadratic model. Sensitization enhancement ratios (SER{sub 10}) were calculated as the ratio of doses required to achieve 10% surviving fraction for cells without and with DNA-incorporated IUdR. Results: At 4 MV, SER{sub 10} values were 2.6 {+-} 0.1, 2.2 {+-} 0.1, and 1.5 {+-} 0.1 for 16.6%, 12.0%, and 9.2% thymidine replacement, respectively. At 35 keV, SER{sub 10} values were 4.1 {+-} 0.2, 3.0 {+-} 0.1, and 2.0 {+-} 0.1, respectively, which yielded SER{sub 10} ratios (35 keV:4 MV) of 1.6 {+-} 0.1, 1.4 {+-} 0.1, and 1.3 {+-} 0.1, respectively. Conclusions: SER{sub 10} increases monotonically with percent thymidine replacement by IUdR for both modalities. As compared to 4-MV x-rays, 35-keV photons produce enhanced SER{sub 10} values whose ratios are linear with percent thymidine replacement and assumed to be due to Auger electrons contributing to enhanced dose to DNA. Although this Auger effectiveness factor is less than the radiosensitization factor of IUdR, both could be important for the clinical efficacy of IUdR radiotherapy.

  1. Evaluation of new iodinated acridine derivatives for targeted radionuclide therapy of melanoma using 125I, an Auger electron emitter.

    PubMed

    Gardette, Maryline; Papon, Janine; Bonnet, Mathilde; Desbois, Nicolas; Labarre, Pierre; Wu, Ting-Dee; Miot-Noirault, Elisabeth; Madelmont, Jean-Claude; Guerquin-Kern, Jean-Luc; Chezal, Jean-Michel; Moins, Nicole

    2011-12-01

    The increasing incidence of melanoma and the lack of effective therapy on the disseminated form have led to an urgent need for new specific therapies. Several iodobenzamides or analogs are known to possess specific affinity for melanoma tissue. New heteroaromatic derivatives have been designed with a cytotoxic moiety and termed DNA intercalating agents. These compounds could be applied in targeted radionuclide therapy using (125)I, which emits Auger electrons and gives high-energy, localized irradiation. Two iodinated acridine derivatives have been reported to present an in vivo kinetic profile conducive to application in targeted radionuclide therapy. The aim of the present study was to perform a preclinical evaluation of these compounds. The DNA intercalating property was confirmed for both compounds. After radiolabeling with (125)I, the two compounds induced in vitro a significant radiotoxicity to B16F0 melanoma cells. Nevertheless, the acridine compound appeared more radiotoxic than the acridone compound. While cellular uptake was similar for both compounds, SIMS analysis and in vitro protocol showed a stronger affinity for melanin with acridone derivative, which was able to induce a predominant scavenging process in the melanosome and restrict access to the nucleus. In conclusion, the acridine derivative with a higher nuclear localization appeared a better candidate for application in targeted radionuclide therapy using (125)I. PMID:20567996

  2. Dependence of the backscattering factor in aes on the primary electron incidence angle

    NASA Astrophysics Data System (ADS)

    Jabłoński, Aleksander

    1983-01-01

    The formulas defining the backscattering factor met with in the literature are derived from the general definition. These formulas are shown to depend on the simplifying assumptions made in the derivation. The Monte Carlo algorithm is used to calculate the dependence of the backscattering factor on the primary electron incidence angle for different defining formulas. Considerable differences were found between values of the backscattering factor resulting from these definitions at grazing incidence of primary electrons.

  3. Nanodosimetry of Auger electrons: A case study from the decay of 125I and 0–18-eV electron stopping cross sections of cytosine

    PubMed Central

    Michaud, M.; Bazin, M.; Sanche, L.

    2013-01-01

    Radiopharmaceuticals emitting Auger electrons are often injected into patients undergoing cancer treatment with targeted radionuclide therapy (TRT). In this type of radiotherapy, the radiation source is radial and most of the emitted primary particles are low-energy electrons (LEEs) having kinetic energies distributed mostly from zero to a few hundred electron volts with very short ranges in biological media. These LEEs generate a high density of energy deposits and clustered damage, thus offering a relative biological effectiveness comparable to that of alpha particles. In this paper, we present a simple model and corresponding measurements to assess the energy deposited near the site of the radiopharmaceuticals in TRT. As an example, a calculation is performed for the decay of a single 125I radionuclide surrounded by a 1-nm-radius spherical shell of cytosine molecules using the energy spectrum of LEEs emitted by 125I along with their stopping cross sections between 0 and 18 eV. The dose absorbed by the cytosine shell, which occupies a volume of 4 nm3, is extremely high. It amounts to 79 kGy per decay of which 3%, 39%, and 58% is attributed to vibrational excitations, electronic excitations, and ionization processes, respectively. PMID:24976798

  4. Nanodosimetry of Auger electrons: A case study from the decay of (125)I and 0-18-eV electron stopping cross sections of cytosine.

    PubMed

    Michaud, M; Bazin, M; Sanche, L

    2013-03-01

    Radiopharmaceuticals emitting Auger electrons are often injected into patients undergoing cancer treatment with targeted radionuclide therapy (TRT). In this type of radiotherapy, the radiation source is radial and most of the emitted primary particles are low-energy electrons (LEEs) having kinetic energies distributed mostly from zero to a few hundred electron volts with very short ranges in biological media. These LEEs generate a high density of energy deposits and clustered damage, thus offering a relative biological effectiveness comparable to that of alpha particles. In this paper, we present a simple model and corresponding measurements to assess the energy deposited near the site of the radiopharmaceuticals in TRT. As an example, a calculation is performed for the decay of a single (125)I radionuclide surrounded by a 1-nm-radius spherical shell of cytosine molecules using the energy spectrum of LEEs emitted by (125)I along with their stopping cross sections between 0 and 18 eV. The dose absorbed by the cytosine shell, which occupies a volume of 4 nm(3), is extremely high. It amounts to 79 kGy per decay of which 3%, 39%, and 58% is attributed to vibrational excitations, electronic excitations, and ionization processes, respectively. PMID:24976798

  5. Nanodosimetry of Auger electrons: A case study from the decay of 125I and 0-18-eV electron stopping cross sections of cytosine

    NASA Astrophysics Data System (ADS)

    Michaud, M.; Bazin, M.; Sanche, L.

    2013-03-01

    Radiopharmaceuticals emitting Auger electrons are often injected into patients undergoing cancer treatment with targeted radionuclide therapy (TRT). In this type of radiotherapy, the radiation source is radial and most of the emitted primary particles are low-energy electrons (LEEs) having kinetic energies distributed mostly from zero to a few hundred electron volts with very short ranges in biological media. These LEEs generate a high density of energy deposits and clustered damage, thus offering a relative biological effectiveness comparable to that of alpha particles. In this paper, we present a simple model and corresponding measurements to assess the energy deposited near the site of the radiopharmaceuticals in TRT. As an example, a calculation is performed for the decay of a single 125I radionuclide surrounded by a 1-nm-radius spherical shell of cytosine molecules using the energy spectrum of LEEs emitted by 125I along with their stopping cross sections between 0 and 18 eV. The dose absorbed by the cytosine shell, which occupies a volume of 4 nm3, is extremely high. It amounts to 79 kGy per decay of which 3%, 39%, and 58% is attributed to vibrational excitations, electronic excitations, and ionization processes, respectively.

  6. NHEXAS PHASE I REGION 5 STUDY--STANDARD OPERATING PROCEDURE FOR METTLER AE160 ELECTRONIC BALANCE (NHX/SOP-160-009)

    EPA Science Inventory

    This procedure describes the process of calibrating the Mettler AE 160, an electronic, single range analytical balance with an enclosed weighing pan. The weight range for this balance is 0-162 g (0.1 mg readability). It was required that the balance be calibrated annually by the ...

  7. Evaluation of two (125)I-radiolabeled acridine derivatives for Auger-electron radionuclide therapy of melanoma.

    PubMed

    Gardette, Maryline; Viallard, Claire; Paillas, Salomé; Guerquin-Kern, Jean-Luc; Papon, Janine; Moins, Nicole; Labarre, Pierre; Desbois, Nicolas; Wong-Wah-Chung, Pascal; Palle, Sabine; Wu, Ting-Di; Pouget, Jean-Pierre; Miot-Noirault, Elisabeth; Chezal, Jean-Michel; Degoul, Francoise

    2014-08-01

    We previously selected two melanin-targeting radioligands [(125)I]ICF01035 and [(125)I]ICF01040 for melanoma-targeted (125)I radionuclide therapy according to their pharmacological profile in mice bearing B16F0 tumors. Here we demonstrate in vitro that these compounds present different radiotoxicities in relation to melanin and acidic vesicle contents in B16F0, B16F0 PTU and A375 cell lines. ICF01035 is effectively observed in nuclei of achromic (A375) melanoma or in melanosomes of melanized melanoma (B16F0), while ICF01040 stays in cytoplasmic vesicles in both cells. [(125)I]ICF01035 induced a similar survival fraction (A50) in all cell lines and led to a significant decrease in S-phase cells in amelanotic cell lines. [(125)I]ICF01040 induced a higher A50 in B16 cell lines compared to [(125)I]ICF01035 ones. [(125)I]ICF01040 induced a G2/M blockade in both A375 and B16F0 PTU, associated with its presence in cytoplasmic acidic vesicles. These results suggest that the radiotoxicity of [(125)I]ICF01035 and [(125)I]ICF01040 are not exclusively reliant on DNA alterations compatible with γ rays but likely result from local dose deposition (Auger electrons) leading to toxic compound leaks from acidic vesicles. In vivo, [(125)I]ICF01035 significantly reduced the number of B16F0 lung colonies, enabling a significant increase in survival of the treated mice. Targeting melanosomes or acidic vesicles is thus an option for future melanoma therapy. PMID:24691673

  8. Resonant Auger studies of metallic systems

    SciTech Connect

    Coulthard, I.; Antel, W. J., Jr.; Frigo, S. P.; Freeland, J. W.; Moore, J.; Calaway, W. S.; Pellin, M. J.; Mendelsohn, M.; Sham, T. K.; Naftel, S. J.; Stampfl, A. P. J.

    1999-10-21

    Results of resonant Auger spectroscopy experiments are presented for Cu, Co, and oxidized Al. Sub-lifetime narrowing of Auger spectra and generation of sub-lifetime narrowed absorption spectra constructed from Auger yield measurements, were observed. Resonant Auger yields are used to identify three valence states of oxidized Al. Partial absorption yield spectra were derived giving detailed electronic information and thickness information for the various chemical states of the bulk metal, the passivating aluminum oxide layer, and the metal-oxide interface region. In addition, the total absorption yield spectrum for the oxidized Al sample was constructed from the partial yield data, supporting the consistency of the authors method.

  9. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    SciTech Connect

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks on the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.

  10. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    DOE PAGESBeta

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks onmore » the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.« less

  11. Site-dependent Si KL{sub 23}L{sub 23} resonant Auger electron spectra following inner-shell excitation of Cl{sub 3}SiSi(CH{sub 3}){sub 3}

    SciTech Connect

    Suzuki, Isao H.; Endo, Hikari; Nagai, Kanae; Nagaoka, Shin-ichi; Takahashi, Osamu; Tamenori, Yusuke

    2013-11-07

    Spectator resonant Auger electron spectra with the Si 1s photoexcitation of Cl{sub 3}SiSi(CH{sub 3}){sub 3} have been measured using an electron spectroscopic technique combined with undulator radiation. The transition with the highest intensity in the total ion yield (TIY) spectrum, coming from excitation of a Si 1s electron on the Cl-side into a vacant valence orbital, generates the resonant Auger decay in which the excited electron remains in this valence orbital. Photoexcitation of 1s electrons into some Rydberg orbitals induces Auger shake-down transitions, because higher-lying Rydberg orbitals in the two Si atoms closely positioned hold spatially overlapping considerably. A broad TIY peak slightly above the 1s ionization thresholds appreciably yields resonant Auger decays in which a slow photoelectron is re-captured into a higher-lying Rydberg orbital. The normal Auger peak shape at this photon energy is distorted due to a post-collision interaction effect. These findings provide a clear understanding on properties of the excited orbitals which are ambiguous in the measurement of the TIY only.

  12. Remarks on the definition of the backscattering factor in AES

    NASA Astrophysics Data System (ADS)

    Jablonski, Aleksander

    2002-03-01

    It has been shown that the backscattering factor in AES can be defined as an integral of the product of the excitation depth distribution function and the emission depth distribution function. First function describes the number of ionizations as a function of depth while the second function describes the escape probability of Auger electrons created at different depths. The backscattering factor calculated from such definition is found to depend on the Auger electron emission angle. For emission angles up to 40° with respect to surface normal, this dependence is not pronounced. However, influence of the emission angle on the backscattering factor may be substantial at glancing emission angles. Values of the backscattering factor calculated from the proposed algorithm assuming the emission angle equal to 40° differ noticeably from values resulting from the Shimizu expression. The deviation may reach 18% at primary electron energy of 2000 eV. Furthermore, the backscattering factor may become smaller than unity at primary energies close to the ionization energy. This effect has been suggested in earlier studies.

  13. Two-photon photoemission study of competing Auger and surface-mediated relaxation of hot electrons in CdSe quantum dot solids.

    PubMed

    Sippel, Philipp; Albrecht, Wiebke; Mitoraj, Dariusz; Eichberger, Rainer; Hannappel, Thomas; Vanmaekelbergh, Daniel

    2013-04-10

    Solids composed of colloidal quantum dots hold promise for third generation highly efficient thin-film photovoltaic cells. The presence of well-separated conduction electron states opens the possibility for an energy-selective collection of hot and equilibrated carriers, pushing the efficiency above the one-band gap limit. However, in order to reach this goal the decay of hot carriers within a band must be better understood and prevented, eventually. Here, we present a two-photon photoemission study of the 1Pe→1Se intraband relaxation dynamics in a CdSe quantum dot solid that mimics the active layer in a photovoltaic cell. We observe fast hot electron relaxation from the 1Pe to the 1Se state on a femtosecond-scale by Auger-type energy donation to the hole. However, if the oleic acid capping is exchanged for hexanedithiol capping, fast deep hole trapping competes efficiently with this relaxation pathway, blocking the Auger-type electron-hole energy exchange. A slower decay becomes then visible; we provide evidence that this is a multistep process involving the surface. PMID:23506122

  14. THE ELECTRONIC STRUCTURE OF AG/CU(100) SURFACE ALLOYS STUDIES BY AUGER-PHOTOELECTRON COINCIDENCE SPECTROSCOPY.

    SciTech Connect

    ARENA,D.A.; BARTYNSKI,R.A.; HULBERT,S.L.

    2001-10-08

    We have measured the Ag and Pd M{sub 5}VV Auger spectrum in coincidence with Ag and Pd 4d{sub 5/2} photoelectrons for the Ag/Cu(100) and Pd/Cu(100) systems, respectively, as a function of admetal coverage. These systems form surface alloys (i.e. random substitutional alloys in the first atomic layer) for impurity concentrations in the 0.1 monolayer range. For these systems, the centroid of the impurity 4d levels is expected to shift away from the Fermi level by {approx}1 eV [Ruban et al., Journal of Molecular Catalysis. A 115 (1997) 421], an effect that should be easily seen in coincidence core-valence-valence Auger spectra. We find that the impurity Auger spectra of both systems shift in a manner that is consistent with d-band moving away from EF. However, the shift for Pd is considerably smaller than expected, and a shift almost absent for Ag. The disagreement between theory and experiment is most likely caused by the neglect of lattice relaxations in the calculations.

  15. Coal-Sizing Auger

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1985-01-01

    Aft end of auger, like forward, face-piercing end, equipped with hard cutting bits such as diamonds. As auger breaks face, pulls broken coal lumps into jaws and forces them into hardened throat section. There, cutting bits chew up lumps: Clearance between throat and auger shaft sets maximum size for coal particles that pass through. Auger motion pushes coal particles into mixing chamber, where paddles combine them with water.

  16. Temperature dependence of photoluminescence spectra of bilayer two-dimensional electron gases in LaAlO{sub 3}/SrTiO{sub 3} superlattices: coexistence of Auger recombination and single-carrier trapping

    SciTech Connect

    Ma, H. J. Harsan Ariando; Venkatesan, T.; Wang, S. J.

    2015-06-15

    We report emerging photoluminescence (PL) of bilayer two-dimensional electron gases (2DEG) in LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) systems. A strong blue PL emerges in bilayer-2DEGs in LAO/STO/LAO/STO which doesn’t show in LAO/STO. PL band in bilayer-2DEGs includes both nearly temperature independent Auger recombination and temperature dependent free electron trapping while it crossovers from Auger recombination to single carrier trapping in LAO/STO. The PL signal of free electron trapping appears at high temperatures and it is much stronger than Auger recombination in the conducting channel in bilayer 2DEGs. This observation shows that high mobility carriers dominate the carrier dynamics in bilayer-2DEGs in LAO/STO superlattices.

  17. Electron Effective-Attenuation-Length Database

    National Institute of Standards and Technology Data Gateway

    SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

  18. 111In-BnDTPA-F3: an Auger electron-emitting radiotherapeutic agent that targets nucleolin

    PubMed Central

    2012-01-01

    Introduction The F3 peptide (KDEPQRRSARLSAKPAPPKPEPKPKKAPAKK), a fragment of the human high mobility group protein 2, binds nucleolin. Nucleolin is expressed in the nuclei of normal cells but is also expressed on the membrane of some cancer cells. The goal was to investigate the use of 111In-labeled F3 peptide for Auger electron-targeted radiotherapy. Methods F3 was labeled with fluorescein isothiocyanate (FITC) for confocal microscopy and conjugated to p-SCN-benzyl-diethylenetriaminepentaacetic acid (BnDTPA) for labeling with 111In to form 111In-BnDTPA-F3. MDA-MB-231-H2N (231-H2N) human breast cancer cells were exposed to 111In-BnDTPA-F3 and used in cell fractionation, γH2AX immunostaining (a marker of DNA double-strand breaks), and clonogenic assays. In vivo, biodistribution studies of 111In-BnDTPA-F3 were performed in 231-H2N xenograft-bearing mice. In tumor growth delay studies, 111In-BnDTPA-F3 (3 μg, 6 MBq/μg) was administered intravenously to 231-H2N xenograft-bearing mice once weekly for 3 weeks. Results Membrane-binding of FITC-F3 was observed in 231-H2N cells, and there was co-localization of FITC-F3 with nucleolin in the nuclei. After exposure of 231-H2N cells to 111In-BnDTPA-F3 for 2 h, 1.7% of 111In added to the medium was membrane-bound. Of the bound 111In, 15% was internalized, and of this, 37% was localized in the nucleus. Exposure of 231-H2N cells to 111In-BnDTPA-F3 (1 μM, 6 MBq/μg) resulted in a dose-dependent increase in γH2AX foci and in a significant reduction of clonogenic survival compared to untreated cells or cells exposed to unlabeled BnDTPA-F3 (46 ± 4.1%, 100 ± 1.8%, and 132 ± 7.7%, respectively). In vivo, tumor uptake of 111In-BnDTPA-F3 (3 μg, 6 MBq/μg) at 3-h post-injection was 1% of the injected dose per gram (%ID/g), and muscle uptake was 0.5%ID/g. In tumor growth delay studies, tumor growth rate was reduced 19-fold compared to untreated or unlabeled BnDTPA-F3-treated mice (p = 0.023). Conclusion 111In-BnDTPA-F3 is

  19. Simulation of Auger electron emission from nanometer-size gold targets using the Geant4 Monte Carlo simulation toolkit

    NASA Astrophysics Data System (ADS)

    Incerti, S.; Suerfu, B.; Xu, J.; Ivantchenko, V.; Mantero, A.; Brown, J. M. C.; Bernal, M. A.; Francis, Z.; Karamitros, M.; Tran, H. N.

    2016-04-01

    A revised atomic deexcitation framework for the Geant4 general purpose Monte Carlo toolkit capable of simulating full Auger deexcitation cascades was implemented in June 2015 release (version 10.2 Beta). An overview of this refined framework and testing of its capabilities is presented for the irradiation of gold nanoparticles (NP) with keV photon and MeV proton beams. The resultant energy spectra of secondary particles created within and that escape the NP are analyzed and discussed. It is anticipated that this new functionality will improve and increase the use of Geant4 in the medical physics, radiobiology, nanomedicine research and other low energy physics fields.

  20. High resolution positron annihilation induced Auger electron spectroscopy of the CuM 2,3VV-transition and of Cu sub-monolayers on Pd and Fe

    NASA Astrophysics Data System (ADS)

    Mayer, J.; Hugenschmidt, C.; Schreckenbach, K.

    2010-09-01

    We present a high resolution positron annihilation induced Auger Electron Spectroscopy (PAES) of the CuM 2,3VV-transition with the unprecedented energy resolution of Δ/EE <1%. This energy resolution and the highly intense positron source NEPOMUC enabled us to resolve the double peak structure with PAES for the first time within a measurement time of only 5.5 h. In addition, sub-monolayers of Cu were deposited on Fe- and Pd-samples in order to investigate the surface selectivity of PAES in comparison with EAES. The extremely high surface selectivity of PAES due to the different positron affinity of Cu and Fe lead to the result that with only 0.96 monolayer of Cu on Fe more than 55% of the emitted Auger electrons stem from Cu, whereas with EAES the Cu Auger fraction amounted to less than 6%.

  1. Analysis of valence XPS and AES of C, N, O, and F-containing substances by DFT calculations using the model molecules

    NASA Astrophysics Data System (ADS)

    Endo, Kazunaka; Hyodo, Kenji; Takaoka, Kazuchiyo; Ida, Tomonori; Shimada, Shingo; Takagi, Yusuke; Kurmaev, Ernst Z.

    2015-05-01

    Experimental valence X-ray photoelectron spectra (VXPS) and Auger electron spectra (AES) of (Li, C, N, O, F) elements of four solid substances [graphite, GaN, SiO2, LiF] are analyzed by density-functional theory calculations using the model molecules of the unit cell. For the calculations, we use deMon density functional theory (DFT) program to estimate VXPS, core-electron binding energies, and (Li, C, N, O, F)-KVV AES of the solid substances. In the AES simulations, we evaluate theoretical kinetic energies of the AES with our modified calculation method. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. Experimental KVV AES of the (Li, C, N, O) atoms in the substances agree considerably well to simulation of AES obtained with the maximum kinetic energies of the atoms, while, the experimental F KVV AES of LiF is almost in accordance with the spectra from the transition-state kinetic energy calculations.

  2. Multielectron Spectroscopy: The Xenon 4d Hole Double Auger Decay

    SciTech Connect

    Penent, F.; Palaudoux, J.; Lablanquie, P.; Andric, L.; Feifel, R.; Eland, J.H.D.

    2005-08-19

    A magnetic bottle spectrometer of the type recently developed by Eland et al. [Phys. Rev. Lett. 90, 053003 (2003).] has been implemented for use with synchrotron radiation, allowing multidimensional electron spectroscopy. Its application to the Xe 4d double Auger decay reveals all the energy pathways involved. The dominant path is a cascade process with a rapid (6 fs) ejection of a first Auger electron followed by the slower (>23 fs) emission of a second Auger electron. Weaker processes implying 3 electron processes are also revealed, namely, direct double Auger and associated Rydberg series.

  3. Modeling of the energy resolution of a 1 meter and a 3 meter time of flight positron annihilation induced Auger electron spectrometers

    NASA Astrophysics Data System (ADS)

    Fairchild, A.; Chirayath, V.; Gladen, R.; McDonald, A.; Lim, Z.; Chrysler, M.; Koymen, A.; Weiss, A.

    Simion 8.1®simulations were used to determine the energy resolution of a 1 meter long Time of Flight Positron annihilation induced Auger Electron Spectrometer (TOF-PAES). The spectrometer consists of: 1. a magnetic gradient section used to parallelize the electrons leaving the sample along the beam axis, 2. an electric field free time of flight tube and 3. a detection section with a set of ExB plates that deflect electrons exiting the TOF tube into a Micro-Channel Plate (MCP). Simulations of the time of flight distribution of electrons emitted according to a known secondary electron emission distribution, for various sample biases, were compared to experimental energy calibration peaks and found to be in excellent agreement. The TOF spectra at the highest sample bias was used to determine the timing resolution function describing the timing spread due to the electronics. Simulations were then performed to calculate the energy resolution at various electron energies in order to deconvolute the combined influence of the magnetic field parallelizer, the timing resolution, and the voltage gradient at the ExB plates. The energy resolution of the 1m TOF-PAES was compared to a newly constructed 3 meter long system. The results were used to optimize the geometry and the potentials of the ExB plates for obtaining the best energy resolution. This work was supported by NSF Grant NSF Grant No. DMR 1508719 and DMR 1338130.

  4. Auger Emitting Radiopharmaceuticals for Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Falzone, Nadia; Cornelissen, Bart; Vallis, Katherine A.

    Radionuclides that emit Auger electrons have been of particular interest as therapeutic agents. This is primarily due to the short range in tissue, controlled linear paths and high linear energy transfer of these particles. Taking into consideration that ionizations are clustered within several cubic nanometers around the point of decay the possibility of incorporating an Auger emitter in close proximity to the cancer cell DNA has immense therapeutic potential thus making nuclear targeted Auger-electron emitters ideal for precise targeting of cancer cells. Furthermore, many Auger-electron emitters also emit γ-radiation, this property makes Auger emitting radionuclides a very attractive option as therapeutic and diagnostic agents in the molecular imaging and management of tumors. The first requirement for the delivery of Auger emitting nuclides is the definition of suitable tumor-selective delivery vehicles to avoid normal tissue toxicity. One of the main challenges of targeted radionuclide therapy remains in matching the physical and chemical characteristics of the radionuclide and targeting moiety with the clinical character of the tumor. Molecules and molecular targets that have been used in the past can be classified according to the carrier molecule used to deliver the Auger-electron-emitting radionuclide. These include (1) antibodies, (2) peptides, (3) small molecules, (4) oligonucleotides and peptide nucleic acids (PNAs), (5) proteins, and (6) nanoparticles. The efficacy of targeted radionuclide therapy depends greatly on the ability to increase intranuclear incorporation of the radiopharmaceutical without compromising toxicity. Several strategies to achieve this goal have been proposed in literature. The possibility of transferring tumor therapy based on the emission of Auger electrons from experimental models to patients has vast therapeutic potential, and remains a field of intense research.

  5. Direct Observation of the Surface Segregation of Cu in Pd by Time-Resolved Positron-Annihilation-Induced Auger Electron Spectroscopy

    SciTech Connect

    Mayer, J.; Hugenschmidt, C.; Schreckenbach, K.

    2010-11-12

    Density functional theory calculations predict the surface segregation of Cu in the second atomic layer of Pd which has not been unambiguously confirmed by experiment so far. We report measurements on Pd surfaces covered with three and six monolayers of Cu using element selective positron-annihilation-induced Auger electron spectroscopy (PAES) which is sensitive to the topmost atomic layer. Moreover, time-resolved PAES, which was applied for the first time, enables the investigation of the dynamics of surface atoms and hence the observation of the segregation process. The time constant for segregation was experimentally determined to {tau}=1.38(0.21) h, and the final segregated configuration was found to be consistent with calculations. Time-dependent PAES is demonstrated to be a novel element selective technique applicable for the investigation of, e.g., heterogeneous catalysis, corrosion, or surface alloying.

  6. Auger electron spectroscopy and x-ray photoelectron spectroscopy of the biocorrosion of copper by Gum Arabic, BCS and Pseudomonas atlantica exopolymer

    SciTech Connect

    Jolley, J.G.; Geesey, G.G.; Hankins, M.R.; Wright, R.B.; Wichlacz, P.L.

    1987-01-01

    Thin films (3.4 nm) of copper on germanium substrates were exposed to 10% Gum Arabic aqueous solution, 1% BCS (aqueous and simulated sea water solutions) and 0.5% Pseudomonas atlantica exopolymer (aqueous and simulated sea water solutions). Pre- and post-exposure characterization were done by Auger electron spectroscopy and x-ray photoelectron spectroscopy. Ancillary graphite furnace atomic absorption spectroscopy was used to monitor the removal process of the copper thin film from the germanium substrate. Results indicate that the copper was oxidized by the Gum Arabic and BCS, and some was removed from the Cu/Ge interface by all three polymers and incorporated into the polymer matrix. Thus biocorrosion of copper was exhibited by the Gum Arabic, BCS and Pseudomonas atlantica exopolymer. 14 refs., 4 figs., 3 tabs.

  7. Variations of surface roughness for deposition of Co-sputtered-ZnO(002) by Auger electron spectroscopy and surface magneto-optic Faraday effect

    NASA Astrophysics Data System (ADS)

    Chang, Y.-C.; Su, C.-W.; Chang, S.-C.; Lee, Y.-H.

    2011-02-01

    Auger electron spectroscopy and the surface magneto-optical Faraday effect were used to monitor the deposition of Co ultrathin films on an initially rough ZnO(002) crystal surface. The magnetic properties of the epitaxial films were compared with those associated with that the structure properties in a 3D island growth mode. The magneto-optic signals are very sensitive to the thickness of the Co film structure, even if it is rough. The ZnO(002) substrate surface formed by routine ion sputtering may exhibit short-range ordering in the initial sample preparation. The roughness of a sputtered substrate surface can be determined from the sensitive magneto-optical signals, especially when ultrathin films are deposited in the initial stage of growth.

  8. Surface characterization of hydrogen charged and uncharged alpha-2 and gamma titanium aluminide alloys using AES and REELS

    NASA Technical Reports Server (NTRS)

    Shanabarger, M. R.

    1990-01-01

    The surfaces of selected uncharged and hydrogen charged alpha-2 and gamma titanium aluminide alloys with Nb additions were characterized by Auger electron (AES) and reflected electron energy loss (REELS) spectroscopy. The alloy surfaces were cleaned before analysis at room temperature by ion sputtering. The low energy (500 eV) ion sputtering process preferentially sputtered the surface concentration. The surface concentrations were determined by comparing AES data from the alloys with corresponding data from elemental references. No differences were observed in the Ti or Nb Auger spectra for the uncharged and hydrogen charged alloys, even though the alpha-2 alloy had 33.4 atomic percent dissolved hydrogen. Also, no differences were observed in the AES spectra when hydrogen was adsorbed from the gas phase. Bulk plasmon energy shifts were observed in all alloys. The energy shifts were induced either by dissolved hydrogen (alpha-2 alloy) or hydrogen adsorbed from the gas phase (alpha-2 and gamma alloys). The adsorption induced plasmon energy shifts were greatest for the gamma alloy and cp-Ti metal.

  9. Angular distribution measurements of the xenon N{sub 4,5}O{sub 2,3}O{sub 2,3} Auger electrons: Determination of alignment and intrinsic parameters

    SciTech Connect

    Snell, G.; Kukk, E.; Berrah, N.

    2000-04-01

    In the framework of the two-step model of Auger decay the alignment of the xenon 4d{sup -1} primary hole states has been derived as a function of photon energy. This quantity was obtained from angular distribution measurements of the N{sub 4,5}O{sub 2,3}O{sub 2,3} Auger lines after ionization of free atoms by monochromatized synchrotron radiation of 80-250 eV photon energy. The data show a minimum of the alignment parameter in the Cooper minimum of the 4d photoionization cross section, which proves the vanishing of the outgoing {epsilon}f electron wave. Furthermore, the intrinsic parameters for all lines in this Auger group were determined and are compared with previous experiments and calculations. (c) 2000 The American Physical Society.

  10. Multiple direct and sequential Auger effect in the rare gases

    SciTech Connect

    Penent, F.; Lablanquie, P.; Palaudoux, J.; Andric, L.; Aoto, T.; Ito, K.; Hikosaka, Y.; Feifel, R.; Eland, J. H. D.

    2006-01-09

    The use of a magnetic bottle spectrometer with synchrotron radiation allows multi dimensional electron spectroscopy to be performed by detecting in coincidence all electrons (2, 3, 4) ejected in multiple ionization events. Multiple Auger effect following inner-shell ionization can be investigated in this way. Application of the technique to rare gases (Xe 4d and Kr 3d) double Auger decay reveals all the energy pathways involved. The dominant decay path proceeds by Auger cascade through autoionizing states of the doubly charged ion. Processes where 3 electrons are involved are also observed as direct double Auger and as involving precursor Rydberg series.

  11. Radiolabeling and in vitro evaluation of 67Ga-NOTA-modular nanotransporter – A potential Auger electron emitting EGFR-targeted radiotherapeutic

    PubMed Central

    Koumarianou, Eftychia; Slastnikova, Tatiana A.; Pruszynski, Marek; Rosenkranz, Andrey A.; Vaidyanathan, Ganesan; Sobolev, Alexander S.; Zalutsky, Michael R.

    2014-01-01

    Introduction Modular nanotransporters (MNTs) are vehicles designed to transport drugs from the cell surface via receptor-mediated endocytosis and endosomal escape to nucleus. Hence their conjugation to Auger electron emitters, can cause severe cell killing, by nuclear localization. Herein we evaluate the use of MNT as a platform for targeted radiotherapy with 67Ga. Methods EGF was the targeting ligand on the MNT, and NOTA was selected for its radiolabeling with 67Ga. In the radiolabeling study we dealt with the precipitation of MNT (pI 5.7) at the labeling pH (4.5–5.5) of 67Ga. Cellular and nuclei uptake of 67Ga-NOTA-MNT by the A431 cell line was determined. Its specific cytotoxicity was compared to that of 67Ga-EDTA, 67Ga-NOTA-BSA and 67Ga-NOTA-hEGF, in A431 and U87MGWTT, cell lines, by clonogenic assay. Dosimetry studies were also performed. Results 67Ga-NOTA-MNT was produced with 90% yield and specific activity of 25.6 mCi/mg. The in vitro kinetics revealed an increased uptake over 24 h. 55% of the internalized radioactivity was detected in the nuclei at 1 h. The cytotoxicity of 67Ga-NOTA-MNT on A431 cell line was 17 and 385-fold higher when compared to non-specific 67Ga-NOTA-BSA and 67Ga-EDTA. While its cytotoxic potency was 13 and 72 – fold higher when compared to 67Ga-NOTA-hEGF in the A431 and the U87MGWTT cell lines, respectively, validating its nuclear localization. The absorbed dose, for 63% cell killing, was 9 Gy, confirms the high specific index of 67Ga. Conclusion These results demonstrate the feasibility of using MNT as a platform for single cell kill targeted radiotherapy by Auger electron emitters. PMID:24776093

  12. Outreach activities within Auger

    NASA Astrophysics Data System (ADS)

    López Ramírez, Rebeca; Snow, Gregory

    2009-04-01

    The scale and scope of the physics studied at the Auger Observatory offer significant opportunities for original outreach work. Education, outreach, and public relations of the Auger collaboration are coordinated in a task of its own whose goals are to encourage and support a wide range of efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. This report focuses on the impact of the collaboration in Mendoza Province, Argentina, as: the Auger Visitor Center in Malargüe that has hosted over 29,000 visitors since 2001, the Auger Celebration and a collaboration-sponsored science fair held on the Observatory campus in November 2005, the opening of the James Cronin School in Malargüe in November 2006, public lectures, school visits, and courses for science teachers.

  13. Quantification of surface Li in 16. 4% CuLi alloys by direct recoil and auger analysis of element specific chemisorption complexes

    SciTech Connect

    Schmidt, H.K.; Anderson, L.R.; Schultz, J.A.; Krauss, A.; Biwer, B.; Gruen, D.M.; Shamir, N.; Mintz, M.

    1988-05-01

    Methoxyl carbon and oxygen are shown to specifically add to the lithium fraction of a CuLi surface exposed to methanol. The lithium surface fraction isdetermined by direct recoil spectroscopic (DRS) measurement of the H, C, and O added to the surface by methanol exposure and by subsequent comparison to the amounts of C, O, and metal determined by auger electron spectroscopy (AES) or x-ray photoelectron spectroscopy (XPS). Direct determination of surface Li by AES or XPS is complicated by relatively large sampling depths (5 or 20 A). The indirect determination of surface Li by methanol chemisorption/AES has been used to calibrate the sensitivity of 5-keV K/sup +/ DRS for lithium.

  14. An Auger Sputter Profiling Study of Nitrogen and Oxygen Ion Implantations in Two Titanium Alloys

    SciTech Connect

    Barton, B. D., Pope, L. E., Wittberg, T. N.

    1989-07-31

    Samples of two titanium alloys, Ti-6A1-4V and Ti-15V-3Cr-3Sn-3A1, were ion implanted with a combination of nitrogen (N+) and oxygen (O+). For each alloy, implantation parameters were chosen to give implanted nitrogen concentrations of approximately 10 or 50 atomic percent, from a depth of 100 nanometers to a depth of 400 nanometers. In all but one case, dual energy (200 keV and 90 keV) implantations of nitrogen were used to give a relatively uniform nitrogen concentration to a depth of 300 nanometers. In each case, oxygen was implanted at 35 keV, following the nitrogen implantation, to give an oxygen-enriched region near the surface. The implanted samples were then examined by Auger electron spectroscopy (AES) combined with argon ion sputtering. In order to determine the stoichiometry of the nitrogen implanted regions, it was necessary to determine the N (KVV) contribution to the overlapping N (KVV) and Ti (LMM) Auger transitions. It was also necessary to correct for the ion-bombardment-induced compositional changes which have been described in an earlier study of titanium nitride thin films. The corrected AES depth profiles were in good agreement with theoretical predictions.

  15. Challenges for lithium species identification in complementary Auger and X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Hoffmann, M.; Zier, M.; Oswald, S.; Eckert, J.

    2015-08-01

    The combination of high spatial resolution and near-surface chemical information makes Auger electron spectroscopy (AES) a powerful tool for comprehensive surface analysis. The recent interest in lithium metal as an active material in lithium sulphur or lithium air batteries increases the demand for a thorough knowledge of the reactions happening at the electrode interface. Applying AES to the complex surfaces of batteries, however, requires a detailed understanding of the interactions occurring with the highly reactive materials during investigation, especially when using metallic lithium with its passivation layers formed even under glove box atmosphere. The article is focused on the influence of electron beam damage and residual gas under ultra-high vacuum conditions on the observations made. Immediate irradiation effects are shown to highly depend on electron dose leading to misinterpretation the surface composition and a non-sufficient stability of the sample. The results are further supported by coupled X-ray photoelectron spectroscopy (XPS) measurements that help to understand the beam induced phenomena. An improved output of the spectroscopic measurement could be achieved employing AES mappings. This allows an improved insight into the local distribution of different lithium compounds in the material surface and can also be applied to other battery active materials.

  16. Verification of surface polarity of O-face ZnO(0 0 0 1\\OverBar) by quantitative modeling analysis of Auger electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Su, C. W.; Huang, M. S.; Tsai, T. H.; Chang, S. C.

    2012-12-01

    Is crystalline ZnO(0 0 0 1¯) O-face surface believed to be enriched by Zn atoms? This study may get the answer. We proposed a simplified model to simulate surface concentration ratio on (0 0 0 1¯)-O or (0 0 0 1)-Zn surface based on the hard-sphere model. The simulation ratio was performed by integrating electron signals from the assumed Auger emission, in which the electron mean free path and relative atomic layer arrangements inside the different polarity ZnO crystal surface were considered as relevant parameters. After counting more than 100 experimental observations of Zn/O ratios, the high frequency peak ratio was found at around 0.428, which was near the value predicted by the proposed model using the IMFP database. The ratio larger than the peak value corresponds to that observed in the annealed samples. A downward trend of the ratio evaluated on the post-sputtering sample indicates the possibility of a Zn-enriched phase appearing on the annealed O-face surface. This phenomenon can further elucidate the O-deficiency debate on most ZnO materials.

  17. Determination of the surface composition of binary alloys by auger electron spectroscopy: The gold-silver and gold-tin systems. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Overbury, S. H.

    1976-01-01

    Polycrystalline Au-Ag alloy foils of a wide range of composition were cleaned and equilibrated in ultra high vacuum. Using two different types of energy analyzers for comparison, the intensities of the Auger emission from transitions at several energies were measured and normalized to those of pure Au and Ag. A model developed to describe the intensity of Auger emission was applied to the intensities and the surface monolayer compositions of the alloys were thus determined. The Auger data were consistent with enrichment of Ag in the surface monolayer.

  18. The Auger Engineering Radio Array

    NASA Astrophysics Data System (ADS)

    Fuchs, Benjamin

    2012-11-01

    High and ultra-high energy cosmic rays hitting the Earth's atmosphere cause extensive air showers (EAS). In recent years, these cosmic rays have been extensively studied at the Pierre Auger Observatory in Argentina. The EAS mainly consist of charged particles, especially electrons and positrons, which cause electro-magnetic emission in the MHz range by interaction with the Earth's magnetic field. To measure this radio emission, AERA, the Auger Engineering Radio Array, was deployed in October 2010 and commenced regular data acquisition in April 2011. AERA was designed as an engineering array for technology and methodology development towards future large-scale radio arrays. It will allow studies on the radio emission mechanism and the physics capabilities of the detection technique. AERA's unique site within the surface detector array (SD) of the Pierre Auger Observatory provides the possibility of coincident hybrid and super-hybrid EAS detection especially in overlap with the fluorescence telescopes Coihueco and HEAT. Besides a description of the setup, we present an overview of analyses of commissioning data taken between November 2010 and April 2011. Also, we show the first hybrid and self-triggered events detected with AERA in April 2011.

  19. Auger injuries in children.

    PubMed Central

    Letts, R. M.; Gammon, W.

    1978-01-01

    A 6-year review of auger injuries in Manitoba children revealed that 23 children sustained major injuries resulting in amputation of 17 limbs. Auger injuries are the main cause of traumatic amputation in children in Manitoba. Improved safety education for the entire farm family as well as better design of safety shields would decrease this carnage. Images FIG. 1 FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 9 PMID:630513

  20. Investigation of Sn surface segregation during GeSn epitaxial growth by Auger electron spectroscopy and energy dispersive x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Takahiro; Hirose, Nobumitsu; Kasamatsu, Akifumi; Mimura, Takashi; Matsui, Toshiaki; Suda, Yoshiyuki

    2015-02-01

    The mechanism of Sn surface segregation during the epitaxial growth of GeSn on Si (001) substrates was investigated by Auger electron spectroscopy and energy dispersive X-ray spectroscopy. Sn surface segregation depends on the growth temperature and Sn content of GeSn layers. During Sn surface segregation, Sn-rich nanoparticles form and move on the surface during the deposition, which results in a rough surface owing to facet formation. The Sn-rich nanoparticles moving on the surface during the deposition absorb Sn from the periphery and yield a lower Sn content, not on the surface but within the layer, because the Sn surface segregation and the GeSn deposition occur simultaneously. Sn surface segregation can occur at a lower temperature during the deposition compared with that during postannealing. This suggests that the Sn surface segregation during the deposition is strongly promoted by the migration of deposited Ge and Sn adatoms on the surface originating from the thermal effect of substrate temperature, which also suggests that limiting the migration of deposited Ge and Sn adatoms can reduce the Sn surface segregation and improve the crystallinity of GeSn layers.

  1. Auger processes in the 21st century

    PubMed Central

    Howell, Roger W.

    2012-01-01

    Purpose The extreme radiotoxicity of Auger electrons and their exquisite capacity to irradiate specific molecular sites has prompted scientists to extensively investigate their radiobiological effects. Their efforts have been punctuated by quadrennial international symposia that have focused on biophysical aspects of Auger processes. The latest meeting, the 6th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes, was held 5–6 July 2007 at Harvard Medical School in Boston, Massachusetts, USA. This article provides a review of the research in this field that was published during the years 2004–2007, the period that has elapsed since the previous meeting. Conclusion The field has advanced considerably. A glimpse of the potential of this unique form of ionizing radiation to contribute to future progress in a variety of fields of study is proffered. PMID:19061120

  2. Bromine-80m-labeled estrogens: Auger-electron emitting, estrogen receptor-directed ligands with potential for therapy of estrogen receptor positive cancers

    SciTech Connect

    DeSombre, E.R.; Mease, R.C.; Hughes, A.; Harper, P.V.; DeJesus, O.T.; Friedman, A.M.

    1988-01-01

    A triphenylbromoethylene, 1,1-bis(p-hydroxyphenyl)-2-bromo-2-phenylethylene, Br-BHPE, and a bromosteroidal estrogen, 17..cap alpha..- bromovinylestradiol, BrVE/sub 2/, were labeled with the Auger electron emitting nuclide bromine-80m, prepared by the (p,n) reaction with /sup 80/Se. To assess their potential as estrogen receptor (ER) directed therapeutic substrates the bromine-80m labeled estrogens were injected into immature female rats and the tissue distribution studied at 0.5 and 2 hours. Both radiobromoestrogens showed substantial diethylstilbesterol (DES)-inhibitable localization in the ER rich tissues, uterus, pituitary, ovary and vagina at both time points. While the percent dose per gram tissue was higher for the Br-BHPE, the BrVE/sub 2/ showed higher tissue to blood ratios, especially at 2 hr, reflecting the lower blood concentrations of radiobromine following administration of the steroidal bromoestrogen. Comparing intraperitoneal, intravenous and subcutaneous routes of administration for the radiobromine labeled Br-BHPE, the intraperitoneal route was particularly advantageous to provide maximum, DES-inhibitable concentrations in the peritoneal, ER-rich target organs, the uterus, ovary and vagina. While uterine concentrations after BrBHPE were from 10--48% dose/g and after BrVE/sub 2/ were 15--25% dose/g, similar treatment with /sup 80m/Br as sodium bromide showed uniform low concentrations in all tissues at about the levels seen in blood. The effective specific activity of (/sup 80m/Br)BrBHPE, assayed by specific binding to ER in rat uterine cytosol, was 8700 Ci/mmole. 23 refs., 9 figs., 2 tabs.

  3. Electron spectroscopy analysis

    NASA Technical Reports Server (NTRS)

    Gregory, John C.

    1992-01-01

    The Surface Science Laboratories at the University of Alabama in Huntsville (UAH) are equipped with x-ray photoelectron spectroscopy (XPS or ESCA) and Auger electron spectroscopy (AES) facilities. These techniques provide information from the uppermost atomic layers of a sample, and are thus truly surface sensitive. XPS provides both elemental and chemical state information without restriction on the type of material that can be analyzed. The sample is placed into an ultra high vacuum (UHV) chamber and irradiated with x-rays which cause the ejection of photoelectrons from the sample surface. Since x-rays do not normally cause charging problems or beam damage, XPS is applicable to a wide range of samples including metals, polymers, catalysts, and fibers. AES uses a beam of high energy electrons as a surface probe. Following electronic rearrangements within excited atoms by this probe, Auger electrons characteristic of each element present are emitted from the sample. The main advantage of electron induced AES is that the electron beam can be focused down to a small diameter and localized analysis can be carried out. On the rastering of this beam synchronously with a video display using established scanning electron microscopy techniques, physical images and chemical distribution maps of the surface can be produced. Thus very small features, such as electronic circuit elements or corrosion pits in metals, can be investigated. Facilities are available on both XPS and AES instruments for depth-profiling of materials, using a beam of argon ions to sputter away consecutive layers of material to reveal sub-surface (and even semi-bulk) analyses.

  4. Tool for Guiding An Auger

    NASA Technical Reports Server (NTRS)

    Wesselski, C. J.

    1983-01-01

    Auger and Ram have same pitch, which minimizes damage to workpiece and load carried by auger. Auger firmly fastened onto ram shaft by screw and kept from rotating on shaft by slot machined into end of stem and male driving lug that engages slot. Used to install threaded studs in plastic or rubber where impractical to mold them in.

  5. An enhanced security solution for electronic medical records based on AES hybrid technique with SOAP/XML and SHA-1.

    PubMed

    Kiah, M L Mat; Nabi, Mohamed S; Zaidan, B B; Zaidan, A A

    2013-10-01

    This study aims to provide security solutions for implementing electronic medical records (EMRs). E-Health organizations could utilize the proposed method and implement recommended solutions in medical/health systems. Majority of the required security features of EMRs were noted. The methods used were tested against each of these security features. In implementing the system, the combination that satisfied all of the security features of EMRs was selected. Secure implementation and management of EMRs facilitate the safeguarding of the confidentiality, integrity, and availability of e-health organization systems. Health practitioners, patients, and visitors can use the information system facilities safely and with confidence anytime and anywhere. After critically reviewing security and data transmission methods, a new hybrid method was proposed to be implemented on EMR systems. This method will enhance the robustness, security, and integration of EMR systems. The hybrid of simple object access protocol/extensible markup language (XML) with advanced encryption standard and secure hash algorithm version 1 has achieved the security requirements of an EMR system with the capability of integrating with other systems through the design of XML messages. PMID:24037086

  6. An Auger electron spectroscopy study of the activation of iron Fischer-Tropsch catalysts. II. Carbon monoxide activation

    SciTech Connect

    Sault, A.G. ); Datye, A.K. )

    1993-03-01

    Activation procedures can have a dramatic effect on the activity of iron-based catalysts for Fischer-Tropsch (F-T) synthesis. CO conversion over a 100 Fe/3 Cu/0.2 K catalyst (parts by weight) can vary by nearly a factor of 3, depending on activation treatment. In contrast, a 100 Fe/5 Cu/4.2 K/25 SiO[sub 2] catalyst displays little dependence of F-T activity on activation treatment. An ultra-high vacuum surface analysis chamber coupled to an atmospheric reactor has been used to measure the surface composition of these catalysts following activation in carbon monoxide at 280[degrees]C, while transmission electron microscopy (TEM) and BET surface area measurements have been used to investigate catalyst morphology. CO activation of the 100 Fe/5 Cu/4.2 K/25 SiO[sub 2] catalyst at 280[degrees]C results in partial reduction of iron to a mixture of Fe[sub x]O and Fe[sub 3]O[sub 4], and an overall surface composition very similar to that obtained following hydrogen activation at 220 or 280[degrees]C, consistent with the invariance of F-T activity with activation treatment for this catalyst. Activation of the 100 Fe/3 Cu/0.2 K catalyst in CO at 280[degrees]C results in the formation of iron carbide particles, growth of graphitic carbon (C[sub g]) filaments, and formation of a thick, porous, C[sub g] layer covering the carbide particles. Differences in F-T activity between the hydrogen- and CO-activated 100 Fe/3 Cu/0.2 K catalyst are discussed in terms of surface composition and catalyst morphology. The difference in sensitivity of the two catalysts to activation conditions is related to differences in the extent of reduction of the catalysts. 45 refs., 4 figs., 1 tab.

  7. An Auger electron spectroscopy study of the activation of iron Fischer-Tropsch catalysts. I. Hydrogen activation

    SciTech Connect

    Sault, A.G. )

    1993-03-01

    Activation procedures can have a dramatic effect on the activity of iron-based catalysts for Fischer-Tropsch (F-T) synthesis. CO conversion over a 100 Fe/3 Cu/0.2 K catalyst (parts by weight) can vary by nearly a factor of 3, depending on activation. In contrast, a 100 Fe/5 Cu/4.2 K/25 SiO[sub 2] catalyst displays only minor variations in activity with activation conditions. An ultra-high vacuum surface analysis chamber coupled to an atmospheric pressure reactor has been used to measure the surface compositions of these catalysts following various hydrogen activation procedures. Activation of the 100 Fe/3 Cu/0.2 K catalyst in H[sub 2] results in rapid reduction of iron to the metallic state, and segregation of sulfur to the catalyst surface. The sulfur arises from bulk sulfate impurities present in the metal nitrates used to prepare the catalyst. Sulfur coverage increases with both activation time and temperature, due to an increase in the rate of sulfur diffusion with temperature. F-T activity of this catalyst varies inversely with sulfur coverage, consistent with the well-known poisoning effect of sulfur on F-T synthesis. For the 100 Fe/5 Cu/4.2 K/25 SiO[sub 2] catalyst no significant variations in surface composition are observed as a function of hydrogen activation temperature, consistent with the absence of any variations in catalyst activity. Only partial reduction of iron to a mixture of Fe[sub x]O and Fe[sub 3]O[sub 4] is observed for this catalyst for all activation conditions investigated. Using electron beam effects to remove potassium and silica shows that one or both of these components inhibits reduction of iron to the metallic state in the 100 Fe/5 Cu/4.2 K/25 SiO[sub 2] catalyst. 48 refs., 3 tabs.

  8. Auger-architectomics: introducing a new nanotechnology to infectious disease.

    PubMed

    Swart, Chantel W; Pohl, Carolina H; Kock, Johan L F

    2014-01-01

    In 2010, we developed a new imaging nanotechnology called Auger-architectomics, to study drug biosensors in nano-detail. We succeeded in applying Auger atom electron physics coupled to scanning electron microscopy (SEM) and Argon-etching to cell structure exploration, thereby exposing a new dimension in structure and element composition architecture. Auger-architectomics was used to expose the fate and effect of drugs on cells. This technology should now be expanded to diseased cells. This paper will outline the development, proof of concept, and application of this imaging nanotechnology. A virtual tour is available at: http://vimeo.com/user6296337 . PMID:24619614

  9. Uses of Auger and x ray photoelectron spectroscopy in the study of adhesion and friction

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1990-01-01

    Three studies are described characterizing the possible contributions of surface science to tribology. These include surface contamination formed by the interaction of a surface with the environment, contaminants obtained with diffusion of compounds, and surface chemical changes resulting from selective thermal evaporation. Surface analytical tools such as Auger electron spectroscopy (AES) and x ray photoelectron spectroscopy (XPS) incorporated directly into adhesion and friction systems are primarily used to define the nature of tribological surfaces before and after tribological experimentation and to characterize the mechanism of solid-to-solid interaction. Emphasis is on fundamental studies involving the role of surfaces in controlling the adhesion and friction properties of materials emerging as a result of the surface analyses. The materials which were studied include metals and ceramics such as elemental metals, amorphous alloys (metallic glasses), and silicon-based ceramics.

  10. Cluster Chemistry in Electron-Poor Ae-Pt-Cd Systems (Ae=Ca, Sr, Ba): (Sr,Ba)Pt2Cd4, Ca6Pt8Cd16, and Its Known Antitype Er6Pd16Sb8

    SciTech Connect

    Samal, Saroj L.; Gulo, Fakhili; Corbett, John D.

    2013-02-18

    Three new ternary polar intermetallic compounds, cubic Ca6Pt8Cd16, and tetragonal (Sr, Ba)Pt2Cd4 have been discovered during explorations of the Ae–Pt–Cd systems. Cubic Ca6Pt8Cd16 (Fm-3m, Z = 4, a = 13.513(1) Å) contains a 3D array of separate Cd8 tetrahedral stars (TS) that are both face capped along the axes and diagonally bridged by Pt atoms to generate the 3D anionic network Cd8[Pt(1)]6/2[Pt(2)]4/8. The complementary cationic surface of the cell consists of a face-centered cube of Pt(3)@Ca6 octahedra. This structure is an ordered ternary variant of Sc11Ir4 (Sc6Ir8Sc16), a stuffed version of the close relative Na6Au7Cd16, and a network inverse of the recent Er6Sb8Pd16 (compare Ca6Pt8Cd16). The three groups of elements each occur in only one structural version. The new AePt2Cd4, Ae = Sr, Ba, are tetragonal (P42/mnm,Z = 2, a ≈ 8.30 Å, c ≈ 4.47 Å) and contain chains of edge-sharing Cd4 tetrahedra along c that are bridged by four-bonded Ba/Sr. LMTO-ASA and ICOHP calculation results and comparisons show that the major bonding (Hamilton) populations in Ca6Pt8Cd16 and Er6Sb8Pd16 come from polar Pt–Cd and Pd–Sb interactions, that Pt exhibits larger relativistic contributions than Pd, that characteristic size and orbital differences are most evident for Sb 5s, Pt8, and Pd16, and that some terms remain incomparable, Ca–Cd versus Er–Pd.

  11. Effect Of Auger Recombination In An Ion Track

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1993-01-01

    Report presents theoretical calculations of contribution of Auger recombination to depletion of charge carriers from ionization track left by passage of energetic heavy ion through silicon-based electronic device.

  12. AES analysis of barium fluoride thin films

    NASA Astrophysics Data System (ADS)

    Kashin, G. N.; Makhnjuk, V. I.; Rumjantseva, S. M.; Shchekochihin, Ju. M.

    1993-06-01

    AES analysis of thin films of metal fluorides is a difficult problem due to charging and decomposition of such films under electron bombardment. We have developed a simple algorithm for a reliable quantitative AES analysis of metal fluoride thin films (BaF 2 in our work). The relative AES sensitivity factors for barium and fluorine were determined from BaF 2 single-crystal samples. We have investigated the dependence of composition and stability of barium fluoride films on the substrate temperature during film growth. We found that the instability of BaF 2 films grown on GaAs substrates at high temperatures (> 525°C) is due to a loss of fluorine. Our results show that, under the optimal electron exposure conditions, AES can be used for a quantitative analysis of metal fluoride thin films.

  13. Swift heavy ion induced electron emission from solids

    NASA Astrophysics Data System (ADS)

    Rothard, Hermann; Lanzanò, Gaetano; Gervais, Benoit; De Filippo, Enrico; Caron, Michel; Beuve, Michael

    2015-07-01

    We briefly summarize the results of numerous experiments performed at GANIL aimed at measuring electron yields and doubly differential yields (energy or velocity spectra at different ejection angles, angular distributions). These studies, supported by theoretical investigations and numerical simulations, contributed decisively to our understanding of the very first step in energy deposition in matter, i.e. ionization and subsequent electron transport through condensed matter. The emitted electron spectrum contains a rich variety of features including binary encounter electrons (BEE), convoy electrons (CE), Auger electrons (AE) and the low-energy peak of “secondary” electrons (SE).

  14. Interference and PCI in argon Auger (e, 2e) spectra

    NASA Astrophysics Data System (ADS)

    Waterhouse, D. K.; Williams, J. F.

    1997-06-01

    Angle-dependent interference is observed in electron-impact ionization (e, 2e) coincidence experiments on the argon 0953-4075/30/12/013/img1 and 0953-4075/30/12/013/img2 Auger transitions. Recapture of the slow ejected electron from the Auger process leads to interference with the satellite-state ionization processes. The post-collision interaction (PCI) and interference effects are quantified for a large range of excess energies.

  15. Auger Spectroscopy of Hydrogenated Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.; Petukhov, A. G.; Foygel, M.

    1997-01-01

    An energy shift and a change of the line shape of the carbon core-valence-valence Auger spectra are observed for diamond surfaces after their exposure to an electron beam, or annealing at temperatures higher then 950 C. The effect is studied for both natural diamond crystals and chemical-vapor-deposited diamond films. A theoretical model is proposed for Auger spectra of hydrogenated diamond surfaces. The observed changes of the carbon Auger line shape are shown to be related to the redistribution of the valence-band local density of states caused by the hydrogen desorption from the surface. One-electron calculation of Auger spectra of diamond surfaces with various hydrogen coverages are presented. They are based on self-consistent wave functions and matrix elements calculated in the framework of the local-density approximation and the self-consistent linear muffin-tin orbital method with static core-hole effects taken into account. The major features of experimental spectra are explained.

  16. The Auger Star Monitor

    NASA Astrophysics Data System (ADS)

    Diaz, Johana; Nitz, David; Fick, Brian

    2006-04-01

    The Auger Star Monitor (ASM) is designed to automatically measure the total vertical atmospheric extinction above the Auger Observatory. The system continually takes wide-field CCD images of the night sky through a Johnson U-Band filter. Photometry is performed on the star images. The change in recorded star brightness as a function of zenith angle is used to obtain values for the integrated density of atmospheric scattering components. The MTU group has installed two ASMs; one at the Southern Observatory atop the Los Leones Fluorescence Detector building and one at the future site of the Northern Observatory in Colorado. Both of these units have been routinely operating during the past year. Much of our effort has turned to developing better data-reduction algorithms and automated software. Significant work has done to perfect the algorithms for image processing, star identification and photometry. Partial results of extinction coefficients obtained by the ASM will be presented.

  17. Vertically reciprocating auger

    NASA Technical Reports Server (NTRS)

    Etheridge, Mark; Morgan, Scott; Fain, Robert; Pearson, Jonathan; Weldi, Kevin; Woodrough, Stephen B., Jr.

    1988-01-01

    The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input.

  18. AES and EELS tools associated to TRIM simulation methods to study nanostructures on III-V semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Ouerdane, A.; Bouslama, M.; Ghaffour, M.; Abdellaoui, A.; Nouri, A.; Hamaida, K.; Monteuil, Y.

    2012-02-01

    At low energy (300 eV), the Ar+ ions bombardment lead to the formation of small nanodots on the InP and the InSb surface compounds. We used the Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS) to detect the presence of these features. However, these techniques alone do not allow us to determine with accuracy their disturbed dimension related to the height and periodicity. For this reason, we combine these spectroscopy methods with the TRIM (transport and range of ions in matter), SRIM (Stopping and Range of Ion in Matter) and Sigmund simulation methods to show the mechanism of interaction between the argon ions and the III-V compounds cited above and determine the dimension of disturbed areas as a function of Ar+ energy during 30 min.

  19. Valence Auger decay following 3 s photoionization in potassium

    NASA Astrophysics Data System (ADS)

    Palaudoux, J.; Sheinerman, S.; Soronen, J.; Huttula, S.-M.; Huttula, M.; Jänkälä, K.; Andric, L.; Ito, K.; Lablanquie, P.; Penent, F.; Bizau, J.-M.; Guilbaud, S.; Cubaynes, D.

    2015-07-01

    We have studied photoionization in the inner valence 3 s subshell of K and the spectroscopic properties of the two 3 s-1(1S) and (3S) resulting states. Similar to the Rb and Cs cases, the lifetime widths of the (1S) and (3S) states are found to be markedly different, due to the electron correlation effects. The main part of the study deals with the subsequent Auger decay of the 3 s-1 states, which have the particularity to involve low energy (˜5 eV ) Auger electrons. A magnetic bottle spectrometer with a multicoincidence technique has been used to observe and filter the Auger spectra with respect to the K2 + final state. The evolution of these Auger spectra has been investigated near the ionization threshold. They show strong post-collision interaction (PCI) effects, which are well reproduced by semiclassical and eikonal models. They reveal the importance of the photoelectron-Auger-electron interaction associated with these low energy Auger electrons.

  20. Anarchy in AE Aquarii

    NASA Astrophysics Data System (ADS)

    Welsh, W. F.

    Interest in AE Aqr remains high, as evidenced by the lively discussion that took place during the workshop. In this contribution I briefly remark on the results I presented at the workshop, then address topics that were raised during the discussion. I attempt to preserve the spirit and flavor of that discussion.

  1. Binary collision model for neon Auger spectra from neon ion bombardment of the aluminum surface

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1986-01-01

    A model is developed to account for the angle-resolved Auger spectra from neon ion bombardment of the aluminum surface recently obtained by Pepper and Aron. The neon is assumed to be excited in a single asymmetric neon-aluminum-collision and scattered back into the vacuum where it emits an Auger electron. The velocity of the Auger electron acquires a Doppler shift by virtue of the emission from a moving source. The dependence of the Auger peak shape and energy on the incident ion energy, angle of incidence and on the angle of Auger electron emission with respect to the surface is presented. Satisfactory agreement with the angle resolved experimental observations is obtained. The dependence of the angle-integrated Auger yield on the incident ion energy and angle of incidence is also obtained and shown to be in satisfactory agreement with available experimental evidence.

  2. Atomic Auger Doppler effects upon emission of fast photoelectrons.

    PubMed

    Simon, Marc; Püttner, Ralph; Marchenko, Tatiana; Guillemin, Renaud; Kushawaha, Rajesh K; Journel, Loïc; Goldsztejn, Gildas; Piancastelli, Maria Novella; Ablett, James M; Rueff, Jean-Pascal; Céolin, Denis

    2014-01-01

    Studies of photoemission processes induced by hard X-rays including production of energetic electrons have become feasible due to recent substantial improvement of instrumentation. Novel dynamical phenomena have become possible to investigate in this new regime. Here we show a significant change in Auger emission following 1s photoionization of neon, which we attribute to the recoil of the Ne ion induced by the emission of a fast photoelectron. Because of the preferential motion of the ionized Ne atoms along two opposite directions, an Auger Doppler shift is revealed, which manifests itself as a gradual broadening and doubling of the Auger spectral features. This Auger Doppler effect should be a general phenomenon in high-energy photoemission of both isolated atoms and molecules, which will have to be taken into account in studies of other recoil effects such as vibrational or rotational recoil in molecules, and may also have consequences in measurements in solids. PMID:24906107

  3. Molecular cascade Auger decays following Si KL23L23 Auger transitions in SiCl4

    NASA Astrophysics Data System (ADS)

    Suzuki, I. H.; Bandoh, Y.; Mochizuki, T.; Fukuzawa, H.; Tachibana, T.; Yamada, S.; Takanashi, T.; Ueda, K.; Tamenori, Y.; Nagaoka, S.

    2016-08-01

    Cascade Si LVV Auger electron spectra at the photoexcitation of the Si 1s electron in a SiCl4 molecule have been measured using an electron spectrometer combined with monochromatized undulator radiation. In the instance of the resonant excitation of the Si 1s electron into the vacant molecular orbital a peak with high yield is observed at about 106 eV, an energy considerably higher than the energies of the normal LVV Auger electron. This peak is presumed to originate from the participator decay from the state with two 2p holes and one excited electron into the state with one 2p hole and one valence hole. Following the normal KL23L23 Auger transition, the cascade spectrum shows several peak structures, e.g. 63 eV, 76 eV and 91 eV. The peak at 91 eV is probably assigned to the second step Auger decay into states having a 2p hole together with two valence holes. These findings are similar to experimental results of SiF4. The former two peaks (63 eV and 76 eV) are ascribed to Auger transitions of Si atomic ions produced through molecular ion dissociation after the first step cascade decays, although the peak heights of atomic ions are lower than those of SiF4.

  4. Multielectron spectroscopy: Auger decays of the krypton 3d hole

    SciTech Connect

    Palaudoux, J.; Lablanquie, P.; Penent, F.; Andric, L.; Ito, K.; Shigemasa, E.; Eland, J. H. D.; Jonauskas, V.; Kucas, S.; Karazija, R.

    2010-10-15

    The emission of one or two Auger electrons, following Kr 3d inner-shell ionization by synchrotron light, has been investigated both experimentally and theoretically. All electrons emitted in the process are detected in coincidence and analyzed in energy thanks to a magnetic-bottle electron time-of-flight spectrometer. In addition, noncoincident high-resolution electron spectra have been measured to characterize the cascade double-Auger paths more fully. Combination of the two experimental approaches and of our calculations allows a full determination of the decay pathways and branching ratios in the case of Kr 3d single- and double-Auger decays. The Kr{sup 3+} threshold is found at 74.197{+-}0.020 eV.

  5. Multielectron spectroscopy: Auger decays of the krypton 3d hole

    NASA Astrophysics Data System (ADS)

    Palaudoux, J.; Lablanquie, P.; Andric, L.; Ito, K.; Shigemasa, E.; Eland, J. H. D.; Jonauskas, V.; Kučas, S.; Karazija, R.; Penent, F.

    2010-10-01

    The emission of one or two Auger electrons, following Kr 3d inner-shell ionization by synchrotron light, has been investigated both experimentally and theoretically. All electrons emitted in the process are detected in coincidence and analyzed in energy thanks to a magnetic-bottle electron time-of-flight spectrometer. In addition, noncoincident high-resolution electron spectra have been measured to characterize the cascade double-Auger paths more fully. Combination of the two experimental approaches and of our calculations allows a full determination of the decay pathways and branching ratios in the case of Kr 3d single- and double-Auger decays. The Kr3+ threshold is found at 74.197±0.020 eV.

  6. C and N depth profiles of SiCN layers determined with nuclear reaction analyses and AES

    NASA Astrophysics Data System (ADS)

    Link, F.; Baumann, H.; Bethge, K.; Klewe-Nebenius, H.; Bruns, M.

    1998-04-01

    Si 1C xN y layers were prepared by sequential implantation of 40 keV 13C- and 50 keV 15N-ions into c-Si <1 1 1> samples near RT. The carbon and nitrogen depth distributions were measured using the resonant nuclear (p,γ) reactions 15N(p,αγ) 12C at Eres=429 keV and 13C(p,γ) 14N at Eres=1748 keV, respectively. The measured raw data of depth profiling (gamma yield versus the proton beam energy) are converted to concentration-depth profiles of the elements C, N and Si with a common depth scale by using a new developed computer algorithm. These concentration profiles are compared with those obtained with Auger Electron Spectroscopy (AES) and non-Rutherford Backscattering Spectrometry (n-RBS).

  7. Pierre Auger Results

    SciTech Connect

    Chou, Aaron

    2008-01-14

    Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrate that there is a correlation between the arrival directions of cosmic rays with energy above 6 [1] 1019 eV and the positions of active galactic nuclei (AGN) lying within 75 Mpc. We reject the hypothesis of an isotropic distribution of these cosmic rays at over 99% confidence level from a prescribed a priori test. The correlation we observe is compatible with the hypothesis that the highest energy particles originate from relatively nearby extragalactic sources whose fluxes have therefore not been significantly reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

  8. Auger recombination in InN from first principles

    NASA Astrophysics Data System (ADS)

    McAllister, Andrew; Kioupakis, Emmanouil

    Group-III Nitride materials are used in numerous electronic and optoelectronic devices including solid-state lighting, energy conversion, sensor technologies, and high-power electronics. Indium nitride in particular is interesting for fast electronics and optoelectronics in the infrared. Auger recombination is a non-radiative carrier recombination process that would limit the efficiency of these devices. The small band gap (0.7 eV) and the high intrinsic free-electron concentrations in InN possibly make Auger recombination particularly important in this material. We used first-principles computational methods to determine the Auger recombination rates in InN. Our results suggest that direct Auger recombination is dominant in this material and that phonon-assisted Auger processes are not as important as in wider-gap nitrides such as GaN. This research was supported by the National Science Foundation CAREER award through Grant No. DMR-1254314. Computational resources were provided by the DOE NERSC facility.

  9. Radioprotection by DMSO against the biological effects of incorporated radionuclides in vivo--Comparison with other radioprotectors and evidence for indirect action of Auger electrons.

    PubMed

    Goddu, S M; Narra, V R; Harapanhalli, R S; Howell, R W; Rao, D V

    1996-01-01

    Dimethyl sulfoxide (DMSO) was studied for its capacity to protect against the biological effects of chronic irradiation by incorporated radionuclides. Spermatogenesis in mice was used as experimental model and spermatogonial cell survival was the biological endpoint. DMSO was injected intratesticularly 4 h prior to a similar injection of the radiochemical and the spermhead survival determined. Iodine-125 was localized in either the cytoplasm (H125IPDM) or in the DNA (125IUdR) of the testicular cells. Protection was observed against the high-LET type effects of DNA-bound 125I as well as the low-LET effects of cytoplasmically localized 125I with dose modification factors (DMF) of 3.1+/-1.0 and 4.4+/-1.0 respectively. No protection (DMF = 1.1+/-0.1) was observed against the effects of high-LET 5.3 MeV alpha particles of 210Po. The present findings provide supporting evidence that the mechanism responsible for the extreme biological damage caused by DNA-bound Auger emitters is largely radical mediated and therefore indirect in nature. PMID:9004770

  10. Characterization of interfacial failure in SiC reinforced Si3N4 matrix composite material by both fiber push-out testing and Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Eldridge, J. I.; Honecy, F. S.

    1990-01-01

    AES depth profiling and a fiber push-out test for interfacial shear-strength determination have been used to ascertain the mechanical/chemical properties of the fiber/matrix interface in SiC-reinforced reaction-bonded Si3N4, with attention to the weak point where interfacial failure occurs. In the cases of both composite fracture and fiber push-outs, the interfacial failure occurred either between the two C-rich coatings that are present on the double-coated SiC fibers, or between the inner C-rich coating and the SiC fiber. Interface failure occurs at points of very abrupt concentration changes.

  11. El proyecto AUGER

    NASA Astrophysics Data System (ADS)

    Etchegoyen, A.

    Hace ya más de 30 años en Volcano Ranch, EE.UU., un extenso chubasco cósmico (ECC) fue detectado con energía en exceso de 1020 eV. Desde entonces, observatorios ubicados en Haverah Park del Reino Unido, Yakutsk de Rusia, AGASA de Japón y Dugway de EE.UU. también han observado ECC con energías mayores que 1020 eV. Poco se sabe de dichos rayos, y en particular cuál es la naturaleza del primario, de dónde provienen, y cómo son acelerados, pero su naturaleza ultrarelativista excluye la mayoría de las respuestas dejando sólo algunas plausibles de ser investigadas experimentalmente. Grupos de científicos de 20 países están trabajando con el fin de construir dos arreglos de detectores gigantes, uno en cada hemisferio a lo largo de 3000 km2 c/u. Dichas dimensiones son necesarias debido al flujo estimado de 1 rayo cósmico/centuria/km2/sr. La sede del Observatorio del Sur es la Argentina. El proyecto fue nombrado Pierre Auger en conmemoración del célebre físico francés que detectó por primera vez chubascos cósmicos en 1938. El proyecto focaliza su interés en rayos cósmicos con energías mayores que 1020 eV.

  12. Lights, camera, A&E.

    PubMed

    Gould, Mark

    Channel 4 series 24 Hours in A&E was one of the television highlights of 2011. Filmed at King's College Hospital in London, it showed the reality of life in an A&E department and may have improved the public's understanding of nursing. PMID:22324233

  13. AES, EELS and TRIM simulation method study of InP(100) subjected to Ar+, He+ and H+ ions bombardment.

    NASA Astrophysics Data System (ADS)

    Ghaffour, M.; Abdellaoui, A.; Bouslama, M.; Ouerdane, A.; Abidri, B.

    2012-06-01

    Auger Electron Spectroscopy (AES) and Electron Energy Loss Spectroscopy (EELS) have been performed in order to investigate the InP(100) surface subjected to ions bombardment. The InP(100) surface is always contaminated by carbon and oxygen revealed by C-KLL and O-KLL AES spectra recorded just after introduction of the sample in the UHV spectrometer chamber. The usually cleaning process of the surface is the bombardment by argon ions. However, even at low energy of ions beam (300 eV) indium clusters and phosphorus vacancies are usually formed on the surface. The aim of our study is to compare the behaviour of the surface when submitted to He+ or H+ ions bombardment. The helium ions accelerated at 500V voltage and for 45 mn allow removing contaminants but induces damaged and no stoichiometric surface. The proton ions were accelerated at low energy of 500 eV to bombard the InP surface at room temperature. The proton ions broke the In-P chemical bonds to induce the formation of In metal islands. Such a chemical reactivity between hydrogen and phosphorus led to form chemical species such as PH and PH3, which desorbed from the surface. The chemical susceptibly and the small size of H+ advantaged their diffusion into bulk. Since the experimental methods alone were not able to give us with accuracy the disturbed depth of the target by these ions. We associate to the AES and EELS spectroscopies, the TRIM (Transport and Range of Ions in Matter) simulation method in order to show the mechanism of interaction between Ar+, He+ or H+ ions and InP and determine the disturbed depth of the target by argon, helium or proton ions.

  14. Auger width of metastable states in antiprotonic helium

    SciTech Connect

    Revai, J.; Kruppa, A.T.

    1998-01-01

    Auger decay probabilities of metastable states in antiprotonic helium are derived using a minimal extension of the existing bound-state wave functions to account for the electron continuum. Calculations were performed for the Born-Oppenheimer wave functions of Shimamura [Phys. Rev. A {bold 46}, 3776 (1992)] and the variational wave functions of Korobov [Phys. Rev. A {bold 54}, 1749 (1996)]. Our results suggest that the overall accuracy of the Auger widths calculated from the presently available bound-state wave functions is not sufficient. {copyright} {ital 1998} {ital The American Physical Society}

  15. Auger parameter and Wagner plot studies of small copper clusters

    NASA Astrophysics Data System (ADS)

    Moretti, Giuliano; Palma, Amedeo; Paparazzo, Ernesto; Satta, Mauro

    2016-04-01

    We discuss application of the Auger parameter and Wagner plot concepts to the study of small copper clusters deposited on various supports such as C(graphite), SiO2 and Al2O3. We demonstrate that the cluster size and the electronic properties of the support influence the shifts of both the binding energy of the Cu 2p3/2 transition and the kinetic energy of the Cu L3M45M45; 1G Auger transition. We find that the Cu L3M45M45; 1G-2p3/2 Auger parameter and Wagner plot allow one to single out and measure both initial- and final-state effects with a detail which is superior to that achieved in photoemission studies.

  16. Direct and Auger Electron-Induced, Single- and Double-Strand Breaks on Plasmid DNA Caused by 99mTc-Labeled Pyrene Derivatives and the Effect of Bonding Distance.

    PubMed

    Reissig, Falco; Mamat, Constantin; Steinbach, Joerg; Pietzsch, Hans-Juergen; Freudenberg, Robert; Navarro-Retamal, Carlos; Caballero, Julio; Kotzerke, Joerg; Wunderlich, Gerd

    2016-01-01

    It is evident that 99mTc causes radical-mediated DNA damage due to Auger electrons, which were emitted simultaneously with the known γ-emission of 99mTc. We have synthesized a series of new 99mTc-labeled pyrene derivatives with varied distances between the pyrene moiety and the radionuclide. The pyrene motif is a common DNA intercalator and allowed us to test the influence of the radionuclide distance on damages of the DNA helix. In general, pUC 19 plasmid DNA enables the investigation of the unprotected interactions between the radiotracers and DNA that results in single-strand breaks (SSB) or double-strand breaks (DSB). The resulting DNA fragments were separated by gel electrophoresis and quantified by fluorescent staining. Direct DNA damage and radical-induced indirect DNA damage by radiolysis products of water were evaluated in the presence or absence of the radical scavenger DMSO. We demonstrated that Auger electrons directly induced both SSB and DSB in high efficiency when 99mTc was tightly bound to the plasmid DNA and this damage could not be completely prevented by DMSO, a free radical scavenger. For the first time, we were able to minimize this effect by increasing the carbon chain lengths between the pyrene moiety and the 99mTc nuclide. However, a critical distance between the 99mTc atom and the DNA helix could not be determined due to the significantly lowered DSB generation resulting from the interaction which is dependent on the type of the 99mTc binding motif. The effect of variable DNA damage caused by the different chain length between the pyrene residue and the Tc-core as well as the possible conformations of the applied Tc-complexes was supplemented with molecular dynamics (MD) calculations. The effectiveness of the DNA-binding 99mTc-labeled pyrene derivatives was demonstrated by comparison to non-DNA-binding 99mTcO4-, since nearly all DNA damage caused by 99mTcO4- was prevented by incubating with DMSO. PMID:27583677

  17. Manipulation of resonant Auger processes with strong optical fields

    NASA Astrophysics Data System (ADS)

    Picón, Antonio; Buth, Christian; Doumy, Gilles; Krässig, Bertold; Young, Linda; Southworth, Stephen

    2013-05-01

    We recently reported on the optical control of core-excited states of a resonant Auger process in neon. We have focused on the resonant excitation 1 s --> 1s-1 3 p , while a strong optical field may resonantly couple two core-excited states (1s-1 3 p and 1s-1 3 s) in the Rydberg manifold as well as dressing the continuum. There is a clear signature in the Auger electron spectrum of the inner-shell dynamics induced by the strong optical field: i) the Auger electron spectrum is modified by the rapid optical-induced population transfer from the 1s-1 3 p state to the 1s-1 3 s state during their decay. ii) The angular anisotropy parameter, defining the angular distribution of the Auger electron, is manifested in the envelope of the (angle-integrated) sidebands. This work is funded by the Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy, under Contract No. DE-AC02-06CH11357.

  18. Auger electron spectroscopy study of surface segregation in the binary alloys copper-1 atomic percent indium, copper-2 atomic percent tin, and iron-6.55 atomic percent silicon

    NASA Technical Reports Server (NTRS)

    Ferrante, J.

    1973-01-01

    Auger electron spectroscopy was used to examine surface segregation in the binary alloys copper-1 at. % indium, copper-2 at. % tin and iron-6.55 at. % silicon. The copper-tin and copper-indium alloys were single crystals oriented with the /111/ direction normal to the surface. An iron-6.5 at. % silicon alloy was studied (a single crystal oriented in the /100/ direction for study of a (100) surface). It was found that surface segregation occurred following sputtering in all cases. Only the iron-silicon single crystal alloy exhibited equilibrium segregation (i.e., reversibility of surface concentration with temperature) for which at present we have no explanation. McLean's analysis for equilibrium segregation at grain boundaries did not apply to the present results, despite the successful application to dilute copper-aluminum alloys. The relation of solute atomic size and solubility to surface segregation is discussed. Estimates of the depth of segregation in the copper-tin alloy indicate that it is of the order of a monolayer surface film.

  19. In situ auger analysis of surface composition during high fluence ion implantation

    NASA Astrophysics Data System (ADS)

    Baldwin, D. A.; Sartwell, B. D.; Singer, I. L.

    1985-03-01

    A multi-technique ultrahigh vacuum (UHV) target chamber has been used to perform in situ Auger electron spectroscopic (AES) analysis during ion implantation and AES sputter depth profiling of the substrate within 1-2 min after implantation. Iron was implanted with 150 keV Ti + at a 45° angle of incidence in a target chamber with pressures ranging from 8 × 10 -9 Torr of residual gases up to 1 × 10 -5 Torr of intentionally admitted CO gas. A fluence of ∼1.0 × 10 16cm -2 was needed to sputter away the C-covered air-formed oxide. The implanted Ti reached the surface at the 1 at.% level by ∼1.5 × 10 16cm -2. With increasing fluence, the Ti surface concentration increased to ∼15 at.% at steady-state with a curve shape that was concave downward at all fluences. The surface C concentration was found to be proportional to that of Ti for implants in CO, supporting a vacuum carburization model. Substantial O surface concentration (15-20 at.%) was detected for these runs but depth profiles showed only carburization, not oxidation, of the implanted layer. Even in the best vacuum available (8 × 10 -9Torr), some carburization was observed and was attributed to residual gas absorption. An increase in Ti retained dose with increasing CO pressure has been observed but not yet independently confirmed. The Ti/Fe surface concentration ratio is higher for implants done in CO, and this is discussed in terms of modification of the sputter yield for Ti.

  20. Dynamics of Intraband and Interband Auger Processes in Colloidal Core-Shell Quantum Dots.

    PubMed

    Rabouw, Freddy T; Vaxenburg, Roman; Bakulin, Artem A; van Dijk-Moes, Relinde J A; Bakker, Huib J; Rodina, Anna; Lifshitz, Efrat; L Efros, Alexander; Koenderink, A Femius; Vanmaekelbergh, Daniël

    2015-10-27

    Conventional colloidal quantum dots (QDs) suffer from rapid energy losses by nonradiative (Auger) processes, leading to sub-ns lifetimes in all excited states but the lowest-energy single exciton. Suppression of interband Auger decay, such as biexciton Auger recombination, has been achieved with the design of heterostructured core-shell QDs. Auger-like processes are also believed to be responsible for rapid intraband hot-electron cooling in QDs. However, the simultaneous effect of shell growth on interband Auger recombination and intraband hot-electron cooling has not been addressed. Here we investigate how the growth of a CdS shell affects these two relaxation processes in CdSe/CdS core-shell QDs. Using a combination of ultrafast pump-push-probe spectroscopy on the QD ensemble and analysis of the photon statistics from single QDs, we find that Auger losses in the biexciton state are suppressed with increasing shell thickness, while hot-electron cooling remains unaffected. Calculations conducted within an eight-band k·p model confirm the experimental dependence of the biexciton Auger decay on the shell thickness, and provide insights into the factors determining the cooling rate of hot carriers. PMID:26389562

  1. Investigations on the low voltage cathodoluminescence stability and surface chemical behaviour using Auger and X-ray photoelectron spectroscopy on LiSrBO{sub 3}:Sm{sup 3+} phosphor

    SciTech Connect

    Pitale, Shreyas S.; Nagpure, I.M.; Kumar, Vinay; Ntwaeaborwa, O.M.; Terblans, J.J.; Swart, H.C.

    2011-07-15

    Highlights: {yields} Stable orange-red cathodoluminescence observed from LiSrBO{sub 3}:Sm{sup 3+} phosphor. {yields} In situ Auger electron spectroscopy, while monitoring the CL output reduction, reveals surface concentration modification of Li, Sr, B and O atoms. {yields} X-ray photoelectron spectroscopy confirms the formation of SrO{sub 2} layer due to the electron stimulated surface chemical reactions (ESSCRs). This layer is possibly contributing to the surface chemical stability and prevents further degradation. -- Abstract: Orange-red emissive LiSrBO{sub 3}:Sm{sup 3+} phosphors were synthesized through the solid-state reaction method. Under UV radiation (221 nm) and low-voltage electron beam (2 keV, 12 mA/cm{sup 2}) excitation, the Sm{sup 3+} doped LiSrBO{sub 3} phosphor shows emission corresponding to the characteristic {sup 4}G{sub 5/2}-{sup 6}H{sub 7/2} transitions of Sm{sup 3+} with the strongest emission at 601 nm. A high stability of cathodoluminescence (CL) emission during prolong electron bombardment with low-energy electrons was observed. Surface sensitive diagnostic tools such as Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to study the surface chemistry. AES results revealed modifications in the surface concentrations of Li, Sr, B, O and C on the surface of the LiSrBO{sub 3}:Sm{sup 3+} phosphor as indicated by the changes in their Auger peak to peak heights (APPH) as a function of electron dose. Observed changes in the high resolution XPS spectra of the LiSrBO{sub 3}:Sm{sup 3+} surface irradiated with the low energy electron beam provide evidence of compositional and structural changes as a result of the electron beam stimulated surface chemical reactions (ESSCRs). Additional SrO{sub 2} was identified by XPS on the phosphor surface after it received an electron dose of 300 C/cm{sup 2} together with the increase in the concentrations of chemical species containing the B-C-O bonding. The new surface chemical

  2. Characterization of Aes nuclear foci in colorectal cancer cells.

    PubMed

    Itatani, Yoshiro; Sonoshita, Masahiro; Kakizaki, Fumihiko; Okawa, Katsuya; Stifani, Stefano; Itoh, Hideaki; Sakai, Yoshiharu; Taketo, M Mark

    2016-01-01

    Amino-terminal enhancer of split (Aes) is a member of Groucho/Transducin-like enhancer (TLE) family. Aes is a recently found metastasis suppressor of colorectal cancer (CRC) that inhibits Notch signalling, and forms nuclear foci together with TLE1. Although some Notch-associated proteins are known to form subnuclear bodies, little is known regarding the dynamics or functions of these structures. Here, we show that Aes nuclear foci in CRC observed under an electron microscope are in a rather amorphous structure, lacking surrounding membrane. Investigation of their behaviour during the cell cycle by time-lapse cinematography showed that Aes nuclear foci dissolve during mitosis and reassemble after completion of cytokinesis. We have also found that heat shock cognate 70 (HSC70) is an essential component of Aes foci. Pharmacological inhibition of the HSC70 ATPase activity with VER155008 reduces Aes focus formation. These results provide insight into the understanding of Aes-mediated inhibition of Notch signalling. PMID:26229111

  3. Comparison of theory and in situ observations for electron and ion distributions in the near wake of the Explorer 31 and AE-C satellites

    NASA Technical Reports Server (NTRS)

    Samir, U.; Fontheim, E. G.

    1981-01-01

    Measurements of electron density, plasma potential, and mean ion mass from the Explorer 31 satellite, and measurements of ion current, plasma potential, and ion composition from the Atmosphere Explorer C satellite were used in a comparative study with Parker's theory regarding the charged particle distribution in the near wake of an ionospheric satellite (1976). It is shown that theory and experiment agree fairly well in the angle-of-attack range between 90 and 135 deg. In the maximum rarefaction zone (between 145 and 180 deg), however, the theoretical model overestimates the measured ion depletion by several orders of magnitude. A comparison between theory and the Explorer 31 electron measurements shows that the theory again overestimates the electron depletion. These discrepancies are mainly due to the use of a steady-state theory and a single ion equation (using a mean ion mass). Improved agreement between theory and experiment can be obtained by the use of the time-dependent Vlasov-Poisson equations with separate equations for the various ion species.

  4. AES analysis of failures in Cu based electromigration test samples

    NASA Astrophysics Data System (ADS)

    Baunack, S.; Kötter, T. G.; Wendrock, H.; Wetzig, K.

    2001-07-01

    Failures occurring in electromigration test of copper interconnects have been characterized by electron backscatter diffraction (EBSD) and scanning Auger microscopy (SAM). The Cu interconnects were 2 μm wide and 500 nm thick stripes on a Ta/TaN barrier. They are imbedded in trenches in a SiO 2 layer on Si. The failure manifests as the appearance of voids with lateral dimension of some micrometers. By EBSD mapping, it could be verified that no sidewall texture in the interconnect exist. Auger analysis clearly showed that the Ta/TaN barrier layer has not been destroyed at the site of electromigration failure. The interaction of the electron beam with small particles (≈0.5 μm) was modelled to understand the contribution of electron scattering in the voids to the lateral resolution.

  5. Study of the Auger line shape of polyethylene and diamond

    NASA Technical Reports Server (NTRS)

    Dayan, M.; Pepper, S. V.

    1984-01-01

    The KVV Auger electron line shapes of carbon in polyethylene and diamond have been studied. The spectra were obtained in derivative form by electron beam excitation. They were treated by background subtraction, integration and deconvolution to produce the intrinsic Auger line shape. Electron energy loss spectra provided the response function in the deconvolution procedure. The line shape from polyethylene is compared with spectra from linear alkanes and with a previous spectrum of Kelber et al. Both spectra are compared with the self-convolution of their full valence band densities of states and of their p-projected densities. The experimental spectra could not be understood in terms of existing theories. This is so even when correlation effects are qualitatively taken into account account to the theories of Cini and Sawatzky and Lenselink.

  6. RF DESIGN AND OPERATING PERFORMANCE OF THE BNL/AES 1.3 GHZ SINGLE CELL SUPERCONDUCTING RF PHOTOCATHODE ELECTRON GUN.

    SciTech Connect

    COLE, M.; KNEISEL, P.; BEN-ZVI, I.; BURRILL, A.; HAHN, G.; RAO, T.; ZHAO, Y.

    2005-05-16

    Over the past several years Advanced Energy Systems and BNL have been collaborating on the development and testing of a fully superconducting photocathode electron gun. Over the past year we have begun to realize significant results which have been published elsewhere [1]. This paper will review the RF design of the gun under test and present results of its performance under various operating conditions. Results for cavity quality factor will be presented for various operating temperatures and cavity field gradients. We will also discuss future plans for testing using this gun.

  7. (abstract) Airborne Emission Spectrometer (AES)

    NASA Technical Reports Server (NTRS)

    Beer, Reinhard

    1994-01-01

    AES is a low-cost analog of the TES downlooking modes. Because AES operates at ambient temperature, limb-viewing is not possible. The first flight of AES took place in April 1994 on the NASA P3B aircraft out of Wallops Island, VA. While planned as an engineering test flight, spectra were successfully acquired both over the Atlantic Ocean and the area of the Great Dismal Swamp on the Virginia-North Carolina border. At this writing (July 1994), a second series of flights on the NASA DC8 aircraft out of Ames RC,CA is in progress. By the time of the workshop, a third series using the NASA C130 should have been accomplished.

  8. Suppression of auger recombination in ""giant"" core/shell nanocrystals

    SciTech Connect

    Garcia Santamaria, Florencio; Vela, Javier; Schaller, Richard D; Hollingsworth, Jennifer A; Klimov, Victor I; Chen, Yongfen

    2009-01-01

    Many potential applications of semiconductor nanocrystals are hindered by nonradiative Auger recombination wherein the electron-hole (exciton) recombination energy is transferred to a third charge carrier. This process severely limits the lifetime and bandwidth of optical gain, leads to large nonradiative losses in light emitting diodes and photovoltaic cells, and is believed to be responsible for intermittency ('blinking') of emission from single nanocrystals. The development of nanostructures in which Auger recombination is suppressed has been a longstanding goal in colloidal nanocrystal research. Here, we demonstrate that such suppression is possible using so-called 'giant' nanocrystals that consist of a small CdSe core and a thick CdS shell. These nanostructures exhibit a very long biexciton lifetime ({approx}10 ns) that is likely dominated by radiative decay instead of non-radiative Auger recombination. As a result of suppressed Auger recombination, even high-order multiexcitons exhibit high emission efficiencies, which allows us to demonstrate optical amplification with an extraordinarily large bandwidth (>500 me V) and record low excitation thresholds.

  9. X-ray excited Auger transitions of Pu compounds

    SciTech Connect

    Nelson, Art J. Grant, William K.; Stanford, Jeff A.; Siekhaus, Wigbert J.; Allen, Patrick G.; McLean, William

    2015-05-15

    X-ray excited Pu core–valence–valence and core–core–valence Auger line-shapes were used in combination with the Pu 4f photoelectron peaks to characterize differences in the oxidation state and local electronic structure for Pu compounds. The evolution of the Pu 4f core-level chemical shift as a function of sputtering depth profiling and hydrogen exposure at ambient temperature was quantified. The combination of the core–valence–valence Auger peak energies with the associated chemical shift of the Pu 4f photoelectron line defines the Auger parameter and results in a reliable method for definitively determining oxidation states independent of binding energy calibration. Results show that PuO{sub 2}, Pu{sub 2}O{sub 3}, PuH{sub 2.7}, and Pu have definitive Auger line-shapes. These data were used to produce a chemical state (Wagner) plot for select plutonium oxides. This Wagner plot allowed us to distinguish between the trivalent hydride and the trivalent oxide, which cannot be differentiated by the Pu 4f binding energy alone.

  10. Hydrogen slush production with a large auger

    NASA Technical Reports Server (NTRS)

    Daney, D. E.; Arp, V. D.; Voth, R. O.

    1990-01-01

    The design and construction of a 178-mm-diameter auger-type hydrogen slush generator are described. A supercritical helium flow loop, which simulates the performance of a helium refrigerator, cools the generator. The coolant temperature varies down to 5 K and the flow varies about the 1.4 L/s (3 cfm) design point. The computer model of the auger-type generator shows that coolant temperature and auger speed have the greatest influence on slush production rate, although coolant flow rate and auger radial clearance are also important.

  11. Vertical-Screw-Auger Conveyer Feeder

    NASA Technical Reports Server (NTRS)

    Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

    2016-01-01

    A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger. Additional scoops are possible by adding a cylindrical section above the conical funnel section. Such then allows the unit to collect material from swaths larger in diameter than the enclosing casing pipe of the screw auger. A third element includes a flexible screw auger. All three can be used in combination in microgravity and zero atmosphere environments to drill and recover a wide area of subsurface regolith and entrained volatiles through a single access point on the surface.

  12. RELATIVISTIC (E > 0.6, > 2.0, AND > 4.0 MeV) ELECTRON ACCELERATION AT GEOSYNCHRONOUS ORBIT DURING HIGH-INTENSITY, LONG-DURATION, CONTINUOUS AE ACTIVITY (HILDCAA) EVENTS

    SciTech Connect

    Hajra, Rajkumar; Echer, Ezequiel; Gonzalez, Walter D.; Tsurutani, Bruce T.; Santolik, Ondrej

    2015-01-20

    Radiation-belt relativistic (E > 0.6, > 2.0, and > 4.0 MeV) electron acceleration is studied for solar cycle 23 (1995-2008). High-intensity, long-duration, continuous AE activity (HILDCAA) events are considered as the basis of the analyses. All of the 35 HILDCAA events under study were found to be characterized by flux enhancements of magnetospheric relativistic electrons of all three energies compared to the pre-event flux levels. For the E > 2.0 MeV electron fluxes, enhancement of >50% occurred during 100% of HILDCAAs. Cluster-4 passes were examined for electromagnetic chorus waves in the 5 < L < 10 and 0 < MLT < 12 region when wave data were available. Fully 100% of these HILDCAA cases were associated with enhanced whistler-mode chorus waves. The enhancements of E > 0.6, > 2.0, and > 4.0 MeV electrons occurred ∼1.0 day, ∼1.5 days, and ∼2.5 days after the statistical HILDCAA onset, respectively. The statistical acceleration rates for the three energy ranges were ∼1.8 × 10{sup 5}, 2.2 × 10{sup 3}, and 1.0 × 10{sup 1} cm{sup –2} s{sup –1} sr{sup –1} d{sup –1}, respectively. The relativistic electron-decay timescales were determined to be ∼7.7, 5.5, and 4.0 days for the three energy ranges, respectively. The HILDCAAs were divided into short-duration (D ≤ 3 days) and long-duration (D > 3 days) events to study the dependence of relativistic electron variation on HILDCAA duration. For long-duration events, the flux enhancements during HILDCAAs with respect to pre-event fluxes were ∼290%, 520%, and 82% for E > 0.6, > 2.0, and > 4.0 MeV electrons, respectively. The enhancements were ∼250%, 400%, and 27% respectively, for short-duration events. The results are discussed with respect to the current understanding of radiation-belt dynamics.

  13. Relativistic (e > 0.6, > 2.0, and > 4.0 MeV) Electron Acceleration at Geosynchronous Orbit during High-intensity, Long-duration, Continuous AE Activity (HILDCAA) Events

    NASA Astrophysics Data System (ADS)

    Hajra, Rajkumar; Tsurutani, Bruce T.; Echer, Ezequiel; Gonzalez, Walter D.; Santolik, Ondrej

    2015-01-01

    Radiation-belt relativistic (E > 0.6, > 2.0, and > 4.0 MeV) electron acceleration is studied for solar cycle 23 (1995-2008). High-intensity, long-duration, continuous AE activity (HILDCAA) events are considered as the basis of the analyses. All of the 35 HILDCAA events under study were found to be characterized by flux enhancements of magnetospheric relativistic electrons of all three energies compared to the pre-event flux levels. For the E > 2.0 MeV electron fluxes, enhancement of >50% occurred during 100% of HILDCAAs. Cluster-4 passes were examined for electromagnetic chorus waves in the 5 < L < 10 and 0 < MLT < 12 region when wave data were available. Fully 100% of these HILDCAA cases were associated with enhanced whistler-mode chorus waves. The enhancements of E > 0.6, > 2.0, and > 4.0 MeV electrons occurred ~1.0 day, ~1.5 days, and ~2.5 days after the statistical HILDCAA onset, respectively. The statistical acceleration rates for the three energy ranges were ~1.8 × 105, 2.2 × 103, and 1.0 × 101 cm-2 s-1 sr-1 d-1, respectively. The relativistic electron-decay timescales were determined to be ~7.7, 5.5, and 4.0 days for the three energy ranges, respectively. The HILDCAAs were divided into short-duration (D <= 3 days) and long-duration (D > 3 days) events to study the dependence of relativistic electron variation on HILDCAA duration. For long-duration events, the flux enhancements during HILDCAAs with respect to pre-event fluxes were ~290%, 520%, and 82% for E > 0.6, > 2.0, and > 4.0 MeV electrons, respectively. The enhancements were ~250%, 400%, and 27% respectively, for short-duration events. The results are discussed with respect to the current understanding of radiation-belt dynamics.

  14. Sequential double Auger decay in atoms: A quantum informatic analysis

    NASA Astrophysics Data System (ADS)

    Parida, S.; Chandra, N.

    2009-05-01

    We theoretically show that the process of inner-shell photoionization in an atom A, followed by the spontaneous sequential emission of two Auger electrons, produces various kinds of spin-entangled states of three flying electronic qubits. All properties of these states are completely pre-determined by the total spin quantum numbers of the electronic states of four atomic species (i.e., A, A, A, A) participating in this process in the Russell-Saunders coupling. These tripartite states are readily characterized experimentally by measuring only energies of the three emitted electrons, without requiring any entanglement witness or other such protocols.

  15. Resonant Auger Effect at High X-Ray Intensity

    SciTech Connect

    Rohringer, N; Santra, R

    2008-03-27

    The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

  16. Localization effects in the Auger spectra of ring nitrogen systems: Pyridine, poly(2-vinyl)pyridine, borazine, and boron nitride

    SciTech Connect

    Rye, R.R.; Kelber, J.A.; Kellogg, G.E.; Nebesny, K.W.; Lichtenberger, D.L.

    1987-04-15

    The N(KVV) Auger spectra of gas phase pyridine (C/sub 5/H/sub 5/N) and borazine (B/sub 3/N/sub 3/H/sub 6/), and of solid phase poly(2-vinyl)pyridine (PVP) and hexagonal boron nitride ((BN)/sub x/) are reported and analyzed. The data indicate two Auger ''fingerprint'' types of nitrogen. Ammonia (NH/sub 3/) is the prototype for the first, where three of the five valence electrons are sigma bonding and the other two are the lone pair. This localized electronic structure gives rise to relatively sharp features in the N(KVV) spectrum. Typical of the second fingerprint type is pyridine, where there are two sigma bonding electrons, a lone pair of electrons, and one electron contributing to the delocalized ..pi.. system. Theoretical nitrogen Auger transition energies and intensities are calculated for pyridine to demonstrate the general origin of the overlapping features in the relatively broad N(KVV) spectrum of this molecule. PVP fits into the second fingerprint type while borazine and boron nitride give nitrogen Auger spectra more like ammonia. Approximate calculations using the equivalent core concept are used to clarify the relationship between the ammonia, borazine, and boron nitride spectra. It is shown that in these systems the initial Auger state (core--hole) largely localizes the bonds and lone pair on the nitrogen. The Auger spectra show that it is the sigma, ..pi.. and nonbonding orbital characters that provide the Auger fingerprint.

  17. Auger decay and subsequent fragmentation pathways of ethylene following K -shell ionization

    NASA Astrophysics Data System (ADS)

    Gaire, B.; Haxton, D. J.; Sturm, F. P.; Williams, J.; Gatton, A.; Bocharova, I.; Gehrken, N.; Schöffler, M.; Gassert, H.; Zeller, S.; Voigtsberger, J.; Jahnke, T.; Zohrabi, M.; Reedy, D.; Nook, C.; Landers, A. L.; Belkacem, A.; Cocke, C. L.; Ben-Itzhak, I.; Dörner, R.; Weber, Th.

    2015-07-01

    The fragmentation pathways and dynamics of ethylene molecules after core ionization are explored using coincident measurements of the Auger electron and fragment ions by employing the cold target recoil-ion momentum spectroscopy method. The influence of several factors on the dynamics and kinematics of the dissociation is studied. These include propensity rules, ionization mechanisms, symmetry of the orbitals from which the Auger electrons originate, multiple scattering, conical intersections, interference, and possible core-hole localization for the double ionization of this polyatomic molecule. Energy correlation maps allow probing the multidimensional potential energy surfaces and, in combination with our multiconfiguration self-consistent field calculations, identifying the populated electronic states of the dissociating dication. The measured angular distributions of the Auger electrons in the molecular frame further support and augment these assignments. The deprotonation and molecular hydrogen ion elimination channels show a nearly isotropic Auger electron angular distribution with a small elongation along the direction perpendicular to the molecular axis. For the symmetric breakup the angular distributions show a clear influence of multiple scattering on the outgoing electrons. The lowest kinetic energy release feature of the symmetric breakup channel displays a fingerprint of entangled Auger and photoelectron motion in the angular emission pattern identifying this transition as an excellent candidate to probe core-hole localization at a conical intersection of a polyatomic molecule.

  18. Azimuth-dependent Auger neutralization of He{sup +} on Ag(111) and (110) surfaces

    SciTech Connect

    Valdes, Diego; Monreal, R. C.; Blanco, J. M.; Esaulov, V. A.

    2007-04-15

    We present a detailed theoretical analysis of the role played by s and d electrons in Auger neutralization processes of He{sup +} at Ag(111) and Ag(110) surfaces. We calculate crystal-lattice-site Auger neutralization rates as a function of the perpendicular distance between ions and surfaces. We find that the rate is very insensitive to the lateral position for large values of the perpendicular distance because the contribution of the delocalized s electrons dominates in this case. In contrast, the contribution of d electrons dominates at short perpendicular distances and the strong spatial localization of these electrons causes a similar strong dependence of the Auger rate with lateral position. We perform molecular dynamic simulations of scattered ion trajectories, which, used together with the Auger neutralization rates, allow us to obtain the theoretical ion fraction that we compare with our measurements. This parameter-free theory is able to reproduce the magnitude of the ion survival probability and its dependence with the azimuthal angle of incidence for both surfaces of Ag, thus showing the important role played by localized electrons in Auger neutralization of He.

  19. Auger recombination in long-wave infrared InAs/InAsSb type-II superlattices

    SciTech Connect

    Olson, B. V.; Grein, C. H.; Kim, J. K.; Kadlec, E. A.; Klem, J. F.; Hawkins, S. D.; Shaner, E. A.

    2015-12-29

    The Auger lifetime is a critical intrinsic parameter for infrared photodetectors as it determines the longest potential minority carrier lifetime and consequently the fundamental limitations to their performance. Here, Auger recombination is characterized in a long-wave infrared InAs/InAsSb type-II superlattice. Auger coefficients as small as 7.1×10–26 cm6/s are experimentally measured using carrier lifetime data at temperatures in the range of 20 K–80 K. The data are compared to Auger-1 coefficients predicted using a 14-band K•p electronic structure model and to coefficients calculated for HgCdTe of the same bandgap. In conclusion, the experimental superlattice Auger coefficients are found to be an order-of-magnitude smaller than HgCdTe.

  20. Auger recombination in long-wave infrared InAs/InAsSb type-II superlattices

    DOE PAGESBeta

    Olson, B. V.; Grein, C. H.; Kim, J. K.; Kadlec, E. A.; Klem, J. F.; Hawkins, S. D.; Shaner, E. A.

    2015-12-29

    The Auger lifetime is a critical intrinsic parameter for infrared photodetectors as it determines the longest potential minority carrier lifetime and consequently the fundamental limitations to their performance. Here, Auger recombination is characterized in a long-wave infrared InAs/InAsSb type-II superlattice. Auger coefficients as small as 7.1×10–26 cm6/s are experimentally measured using carrier lifetime data at temperatures in the range of 20 K–80 K. The data are compared to Auger-1 coefficients predicted using a 14-band K•p electronic structure model and to coefficients calculated for HgCdTe of the same bandgap. In conclusion, the experimental superlattice Auger coefficients are found to be anmore » order-of-magnitude smaller than HgCdTe.« less

  1. Transport activity of chimaeric AE2-AE3 chloride/bicarbonate anion exchange proteins.

    PubMed Central

    Fujinaga, Jocelyne; Loiselle, Frederick B; Casey, Joseph R

    2003-01-01

    Chloride/bicarbonate anion exchangers (AEs), found in the plasma membrane of most mammalian cells, are involved in pH regulation and bicarbonate metabolism. Although AE2 and AE3 are highly similar in sequence, AE2-transport activity was 10-fold higher than AE3 (41 versus 4 mM x min(-1) respectively), when expressed by transient transfection of HEK-293 cells. AE2-AE3 chimaeras were constructed to define the region responsible for differences in transport activity. The level of AE2 expression was approx. 30% higher than that of AE3. Processing to the cell surface, studied by chemical labelling and confocal microscopy, showed that AE2 is processed to the cell surface approx. 8-fold more efficiently than AE3. The efficiency of cell-surface processing was dependent on the cytoplasmic domain, since the AE2 domain conferred efficient processing upon the AE3 membrane domain, with a predominant role for amino acids 322-677 of AE2. AE2 that was expressed in HEK-293 cells was glycosylated, but little of AE3 was. However, AE2 expressed in the presence of the glycosylation inhibitor, tunicamycin, was not glycosylated, yet retained 85 +/- 8% of anion-transport activity. Therefore glycosylation has little, if any, role in the cell-surface processing or activity of AE2 or AE3. We conclude that the low anion-transport activity of AE3 in HEK-293 cells is due to low level processing to the plasma membrane, possibly owing to protein interactions with the AE3 cytoplasmic domain. PMID:12578559

  2. Acoustic emission characterization using AE (parameter) delay

    NASA Technical Reports Server (NTRS)

    Williams, J. H., Jr.; Lee, S. S.

    1983-01-01

    The acoustic emission (AE) parameter delay concept is defined as that particular measured value of a parameter at which a specified baseline level of cumulative AE activity is reached. The parameter can be from any of a broad range of elastic, plastic, viscoelastic, and fracture mechanics parameters, as well as their combinations. Such parameters include stress, load, strain, displacement, time, temperature, loading cycle, unloading stress, stress intensity factor, strain energy release rate, and crack tip plasticity zone size, while the AE activity may be AE event counts, ringdown counts, energy, event duration, etc., as well as their combinations. Attention is given to examples for the AE parameter delay concept, together with various correlations.

  3. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  4. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  5. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  6. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  7. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  8. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  9. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  10. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  11. Universal size dependence of auger constants in direct- and indirect-gap semiconductor nanocrystals

    SciTech Connect

    Robel, Istvan; Schaller, Richard D; Klimov, Victor I; Gresback, Ryan; Kortshagen, Uwe

    2008-01-01

    Three-dimensional (3D) spatial confinement of electronic wave functions in semiconductor nanocrystals (NCs) results in a significant enhancement of multi-electron phenomena including non radiative Auger recombination. In this process, a conduction-band electron recombines with a valence-band hole by transferring the recombination energy to a third carrier. Significant interest in Auger recombination in NCs has been stimulated by recent studies ofNC lasing, and generation-III photovoltaics enabled by carrier multiplication because in both of these prospective applications Auger recombination represents a dominant carrier-loss mechanism. Here, we perform a side-by-side comparison of Auger recombination rates in NCs of several different compositions including Ge, PbSe, InAs, and CdSe. We observe that the only factor, which has a significant effect on the measured recombination rates, is the size of the NCs but not the details of the material's electronic structure. Most surprisingly, comparable rates are measured for nanocrystals of directand indirect-gap semiconductor NCs despite a dramatic four-to-five orders of magnitude difference in respective bulk-semiconductor Auger constants. This unusual observation can be explained by confinement-induced relaxation of momentum conservation, which smears out the difference between direct- and indirect-gap materials.

  12. Matrix effect in quantitative Auger analysis of binary alloys: Comparison between the measured and the calculated values

    NASA Astrophysics Data System (ADS)

    LI, Ri-Sheng; LI, Chun-Fei

    1990-05-01

    Matrix factors in quantitative AES analyses of binary alloys of AlNi, AuCu, AuNi, CuNi, CuPt and NiPt were studied. Using the in-situ scraping method, matrix factors were experimentally determined with an accuracy better than 5% or 10%. For comparison, matrix factors were calculated using the methods of: Reuter and Seah and Dench (R-SD); Reuter and Tokutaka, Nishimori and Hayashi (R-TNH); Reuter and Tanuma, Powell and Penn (R-TPP); Shimizu and Ichimura and Seah and Dench (SISD); SITNH and SITPP. By comparing the calculated values with the experimental results, we conclude that, the choice of the backscattering factor data, either after R or after SI, only marginally affects the resulting matrix effect despite the fact that their data differ considerably from each other. The most important effect stems from the choice of escape depth. When SD's data are adopted, the calculated values differ significantly from the experimental results except in the case of CuNi. By comparison, when TNH's data (in all of the studied cases) or TPP's data (except in the case of Al-Ni) are adopted, the calculated values are in good agreement with the observed values. This result also implies that the escape depth of Auger electrons depends on the materials in the manner suggested by TNH and TPP rather than the one suggested by SD.

  13. Discovery of radio emission from AE Aquarii

    SciTech Connect

    Bookbinder, J.A.; Lamb, D.Q.

    1987-12-01

    VLA 1.4-GHz and 4.9-GHz observations of six DQ Her cataclysmic variables, obtained in the C/D hybrid configuration with 50-MHz bandwidth, 7-sec time resolution, and limiting flux density about 200 microJy on July 21, 1984, are reported. Variable radio emission with time scale less than 5 min, circular polarization less than 15 percent, and flux density 3-5 mJy at 1.4 GHz and 8-16 mJy at 4.9 GHz is detected from AE Aqr. This emission is tentatively attributed to synchrotron emission from mildly relativistic electrons, powered by the MHD torque coupling the magnetic white dwarf to either (1) a secondary with a strong magnetic field or (2) an accretion disk. 20 references.

  14. Discovery of radio emission from AE Aquarii

    NASA Technical Reports Server (NTRS)

    Bookbinder, J. A.; Lamb, D. Q.

    1987-01-01

    VLA 1.4-GHz and 4.9-GHz observations of six DQ Her cataclysmic variables, obtained in the C/D hybrid configuration with 50-MHz bandwidth, 7-sec time resolution, and limiting flux density about 200 microJy on July 21, 1984, are reported. Variable radio emission with time scale less than 5 min, circular polarization less than 15 percent, and flux density 3-5 mJy at 1.4 GHz and 8-16 mJy at 4.9 GHz is detected from AE Aqr. This emission is tentatively attributed to synchrotron emission from mildly relativistic electrons, powered by the MHD torque coupling the magnetic white dwarf to either (1) a secondary with a strong magnetic field or (2) an accretion disk.

  15. Nonradiative Auger recombination in semiconductor nanocrystals.

    PubMed

    Vaxenburg, Roman; Rodina, Anna; Shabaev, Andrew; Lifshitz, Efrat; Efros, Alexander L

    2015-03-11

    We calculate the rate of nonradiative Auger recombination in negatively charged CdSe nanocrystals (NCs). The rate is nonmonotonic, strongly oscillating with NC size, and sensitive to the NC surface. The oscillations result in nonexponential decay of carriers in NC ensembles. Using a standard single-exponential approximation of the decay dynamics, we determine the apparent size dependence of the Auger rate in an ensemble and derive CdSe surface parameters consistent with the experimental dependence on size. PMID:25693512

  16. The effect of impurities and incident angle on the secondary electron emission of Ni(110)

    NASA Astrophysics Data System (ADS)

    Lazar, Hadar; Patino, Marlene; Raitses, Yevgeny; Koel, Bruce E.; Gentile, Charles; Feibush, Eliot

    2015-11-01

    The investigation of secondary electron emission (SEE) of conducting materials used for magnetic fusion devices and plasma thrusters is important for determining device lifetime and performance. Methods to quantify the secondary electron emission from conducting materials and to characterize the effects that impurities and incident angles have on secondary electron emission were developed using 4-grid low energy electron diffraction (LEED) optics. The total secondary electron yield from a Ni(110) surface was continuously measured from the sample current as surface contamination increased from reactions with background gases in the ultrahigh vacuum chamber. Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) were used to examine the composition and impurity levels on the Ni(110) surface. The total secondary electron yield was also measured at different incident angles. Thank you to the Princeton Plasma Physics Laboratory and the Department of Energy for the opportunity to work on this project through the Science Undergraduate Laboratory Internships.

  17. The effects of impurities and incidence angle on the secondary electron emission of Ni(110)

    NASA Astrophysics Data System (ADS)

    Lazar, Hadar; Patino, Marlene; Raitses, Yevgeny; Koel, Bruce; Gentile, Charles; Feibush, Eliot

    The investigation of secondary electron emission (SEE) of conducting materials used for magnetic fusion devices and plasma thrusters is important for determining device lifetime and performance. Methods to quantify the secondary electron emission from conducting materials and to characterize the effects that impurities and incidence angles have on secondary electron emission were developed using 4-grid low energy electron diffraction (LEED) optics. The total secondary electron yield from a Ni(110) surface was continuously measured from the sample current as surface contamination increased from reactions with background gases in the ultrahigh vacuum chamber. Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) were used to examine the composition and impurity levels on the Ni(110) surface. The total secondary electron yield was also measured at different incidence angles. Thank you to the Princeton Plasma Physics Laboratory (PPPL) and the Department of Energy (DOE) for the opportunity to work on this project through the Science Undergraduate Laboratory Internships (SULI).

  18. Photoelectron recapture and reemission process associated with double Auger decay in Ar

    NASA Astrophysics Data System (ADS)

    Hikosaka, Y.; Mashiko, R.; Odagiri, T.; Adachi, J.; Tanaka, H.; Kosuge, T.; Ito, K.

    2016-06-01

    Multielectron coincidence spectroscopy has been performed for Ar at a photon energy of only 0.2 eV above the 2 p1 /2 threshold. It is revealed that a postcollision interaction induced by double Auger decay leads to photoelectron recapture, followed by reemission of the captured electron, where the recapture of the slow photoelectron forms the A r2 + Rydberg-excited states which subsequently undergo autoionization. The energy correlation of the emitted electrons discloses that both direct and cascade paths in the double Auger decay contribute to the photoelectron recapture.

  19. Infrared observations of AE Aquarii

    NASA Technical Reports Server (NTRS)

    Tanzi, E. G.; Chincarini, G.; Tarenghi, M.

    1981-01-01

    Broadband infrared observations of the cataclysmic variable AE Aquarii are reported. The observations were obtained in the J, H, K and L filters with the InSb photometer attached to the 1-m telescope of the European Southern Observatory. The infrared energy distribution observed from 0.35 to 3.5 microns for phase 0.5 suggests a spectral type of K5 V for the secondary and a distance to the system of approximately 70 pc if an absolute magnitude of 7.3 is assumed. Monitoring of the flux at 2.2 microns reveals a variability with an amplitude of approximately 0.3 magnitude over one third of the orbital period, the nature of which is under investigation.

  20. Operations of and Future Plans for the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Performance and operation of the Surface Detectors of the Pierre Auger Observatory; (2) Extension of the Pierre Auger Observatory using high-elevation fluorescence telescopes (HEAT); (3) AMIGA - Auger Muons and Infill for the Ground Array of the Pierre Auger Observatory; (4) Radio detection of Cosmic Rays at the southern Auger Observatory; (5) Hardware Developments for the AMIGA enhancement at the Pierre Auger Observatory; (6) A simulation of the fluorescence detectors of the Pierre Auger Observatory using GEANT 4; (7) Education and Public Outreach at the Pierre Auger Observatory; (8) BATATA: A device to characterize the punch-through observed in underground muon detectors and to operate as a prototype for AMIGA; and (9) Progress with the Northern Part of the Pierre Auger Observatory.

  1. The Auger Engineering Radio Array and multi-hybrid cosmic ray detection

    NASA Astrophysics Data System (ADS)

    Holt, E. M.; Pierre Auger Collaboration

    2016-05-01

    The Auger Engineering Radio Array (AERA) aims at the detection of air showers induced by high-energy cosmic rays. As an extension of the Pierre Auger Observatory, it measures complementary information to the particle detectors, fluorescence telescopes and to the muon scintillators of the Auger Muons and Infill for the Ground Array (AMIGA). AERA is sensitive to all fundamental parameters of an extensive air shower such as the arrival direction, energy and depth of shower maximum. Since the radio emission is induced purely by the electromagnetic component of the shower, in combination with the AMIGA muon counters, AERA is perfect for separate measurements of the electrons and muons in the shower, if combined with a muon counting detector like AMIGA. In addition to the depth of the shower maximum, the ratio of the electron and muon number serves as a measure of the primary particle mass.

  2. Enhanced radiative auger emission from lithiumlike20Ca17+

    NASA Astrophysics Data System (ADS)

    Bernstein, E. M.; Clark, M. W.; Tanis, J. A.; Graham, W. G.; Morgan, T. J.; Stöckli, M. P.; Berkner, K. H.; Schlachter, A. S.; Stearns, J. W.

    1991-03-01

    Radiative Auger emission (RAE) from lithiumlike20Ca17+ projectiles excited in collisions with He has been measured. The intensity of RAE photons relative to Kα x-ray emission is enhanced by a factor of 10 17 compared with theoretical calculations for ions with few electron vacancies. The enhancement of RAE for Ca17+ is consistent with the results reported previously for lithiumlike16S13+ and23V20+ and indicates a systematic dependence on Z. Both the enhancement and the relative RAE transition rate increase with Z.

  3. Rutherford backscattering and Auger spectroscopy of mercuric iodide detectors

    NASA Astrophysics Data System (ADS)

    Felter, T. E.; Stulen, R. H.; Schnepple, W. F.; Ortale, C.; van den Berg, L.

    1989-11-01

    Palladium contacts on mercuric iodide have been studied using Rutherford backscattering spectroscopy and Auger electron spectroscopy. Results on actual detector contacts show some intermixing of both mercury and iodine with the palladium. To investigate the role of processing variables as a possible cause of this effect we have fabricated model contacts at low temperatures (T ≈ 100 K) and analyzed in situ. The results demonstrated that significant interdiffusion occurs at temperatures as low as 225 K. We conclude that excessive heating during contact deposition could prove to be detrimental to device performance and that the use of cooled substrates during processing should be explored.

  4. Enhanced radiative Auger emission from lithiumlike 16S13+

    NASA Astrophysics Data System (ADS)

    Bernstein, E. M.; Clark, M. W.; Oglesby, C. S.; Tanis, J. A.; Graham, W. G.; McFarland, R. H.; Morgan, T. J.; Johnson, B. M.; Jones, K. W.

    1990-03-01

    The radiative Auger emission (RAE) from 0.94-6.25-MeV/u 16S13+ (lithiumlike) projectiles excited in collisions with He target atoms has been measured. For these highly stripped ions the intensity of RAE photons relative to Kα x-ray emission is enhanced by about a factor of five compared with theoretical calculations and an earlier experimental measurement for S ions with few electron vacancies. The enhancement of RAE for S13+ is qualitatively similar to results reported previously for lithiumlike 23V20+; however, some differences between S and V are evident.

  5. Spin-dependent screening and Auger neutralization of He{sup +} ions in metals

    SciTech Connect

    Alducin, M.; Diez Muino, R.; Juaristi, J.I.

    2004-07-01

    The screening of a He{sup +} ion embedded in a paramagnetic electron gas is studied using density functional theory within the local spin density approximation. We calculate the induced electron density and the induced density of states for each spin orientation, parallel and antiparallel to that of the electron bound to the He{sup +} ion. Our results show that the screening is preferably due to parallel spin electrons, especially for low electron densities of the medium. In a second step, the rates for Auger neutralization of a He{sup +} ion in an electron gas are calculated, paying special attention to their dependence on the spin of the electron excited in the Auger process. The results obtained are used to interpret experiments in which the spin polarization of the emitted yield is measured when a He{sup +} projectile is neutralized in front of a metal surface.

  6. Auger Recombination in Self-Assembled Quantum Dots: Quenching and Broadening of the Charged Exciton Transition.

    PubMed

    Kurzmann, Annika; Ludwig, Arne; Wieck, Andreas D; Lorke, Axel; Geller, Martin

    2016-05-11

    In quantum dots (QDs), the Auger recombination is a nonradiative process in which the electron-hole recombination energy is transferred to an additional carrier. It has been studied mostly in colloidal QDs, where the Auger recombination time is in the picosecond range and efficiently quenches the light emission. In self-assembled QDs, on the other hand, the influence of Auger recombination on the optical properties is in general neglected, assuming that it is masked by other processes such as spin and charge fluctuations. Here, we use time-resolved resonance fluorescence to analyze the Auger recombination and its influence on the optical properties of a single self-assembled QD. From excitation-power-dependent measurements, we find a long Auger recombination time of about 500 ns and a quenching of the trion transition by about 80%. Furthermore, we observe a broadening of the trion transition line width by up to a factor of 2. With a model based on rate equations, we are able to identify the interplay between tunneling and Auger rate as the underlying mechanism for the reduced intensity and the broadening of the line width. This demonstrates that self-assembled QDs can serve as an ideal model system to study how the charge recapture process, given by the band-structure surrounding the confined carriers, influences the Auger process. Our findings are not only relevant for improving the emission properties of colloidal QD-based emitters and dyes, which have recently entered the consumer market, but also of interest for more visionary applications, such as quantum information technologies, based on self-assembled quantum dots. PMID:27087053

  7. Auger Recombination in Self-Assembled Quantum Dots: Quenching and Broadening of the Charged Exciton Transition

    NASA Astrophysics Data System (ADS)

    Kurzmann, Annika; Ludwig, Arne; Wieck, Andreas D.; Lorke, Axel; Geller, Martin

    2016-05-01

    In quantum dots (QDs) the Auger recombination is a non-radiative process, where the electron-hole recombination energy is transferred to an additional carrier. It has been studied mostly in colloidal QDs, where the Auger recombination time is in the ps range and efficiently quenches the light emission. In self-assembled QDs, on the other hand, the influence of Auger recombination on the optical properties is in general neglected, assuming that it is masked by other processes such as spin and charge fluctuations. Here, we use time-resolved resonance fluorescence to analyze the Auger recombination and its influence on the optical properties of a single self-assembled QD. From excitation-power dependent measurements, we find a long Auger recombination time of about 500 ns and a quenching of the trion transition by about 80 percent. Furthermore, we observe a broadening of the trion transition linewidth by up to a factor of two. With a model based on rate equations, we are able to identify the interplay between tunneling and Auger rate as the underlying mechanism for the reduced intensity and the broadening of the linewidth. This demonstrates that self-assembled QDs can serve as an ideal model system to study how the charge recapture process, given by the band-structure surrounding the confined carriers, influences the Auger process. Our findings are not only relevant for improving the emission properties of colloidal QD-based emitters and dyes, which have recently entered the consumer market. They are also of interest for more visionary applications, such as quantum information technologies, based on self-assembled quantum dots.

  8. Looking for Auger signatures in III-nitride light emitters: A full-band Monte Carlo perspective

    SciTech Connect

    Bertazzi, Francesco Goano, Michele; Zhou, Xiangyu; Calciati, Marco; Ghione, Giovanni; Matsubara, Masahiko; Bellotti, Enrico

    2015-02-09

    Recent experiments of electron emission spectroscopy (EES) on III-nitride light-emitting diodes (LEDs) have shown a correlation between droop onset and hot electron emission at the cesiated surface of the LED p-cap. The observed hot electrons have been interpreted as a direct signature of Auger recombination in the LED active region, as highly energetic Auger-excited electrons would be collected in long-lived satellite valleys of the conduction band so that they would not decay on their journey to the surface across the highly doped p-contact layer. We discuss this interpretation by using a full-band Monte Carlo model based on first-principles electronic structure and lattice dynamics calculations. The results of our analysis suggest that Auger-excited electrons cannot be unambiguously detected in the LED structures used in the EES experiments. Additional experimental and simulative work are necessary to unravel the complex physics of GaN cesiated surfaces.

  9. Role of cascade and Auger effects in the enhanced population of the C{sup 3+}(1s2s2p {sup 4}P) states following single-electron capture in C{sup 4+}(1s2s {sup 3}S)-He collisions

    SciTech Connect

    Roehrbein, D.; Kirchner, T.; Fritzsche, S.

    2010-04-15

    The population of excited three-electron states in carbon ions after single-electron capture in 0.5-1.1 MeV/amu C{sup 4+}(1s2s {sup 3}S)-He collisions is analyzed theoretically by combining different methods. While the two-center basis generator method is used to calculate capture amplitudes on the single-particle level, all-electron structure calculations for the relevant C{sup 3+} states and their radiative and Auger transition rates are performed on the multiconfiguration Dirac-Fock level. These data are then combined and fed into a set of classical rate equations for the decay dynamics. Total cross sections for the production of the 1s2s2p {sup 4}P, 1s2s2p {sup 2}P{sub -}, and 1s2s2p {sup 2}P{sub +} states are calculated and their ratios compared with recent experimental data and previous calculations [D. Strohschein et al., Phys. Rev. A 77, 022706 (2008)]. It is found that the relative intensities of the 1s2s2p {sup 4}P states are considerably larger than expected on the basis of pure spin statistics. The Auger transitions, which were not included in the previous calculations, have a significant effect on the final results in that they reduce the 1s2s2p {sup 2}P intensities. Although our extended computations explain a significant part of the production of the 1s2s2p {sup 4}P states, the experimentally observed enhancement of these states is still considerably larger than the theoretical one.

  10. Auger decay of Ar 2p satellite states studied with a multielectron coincidence method

    NASA Astrophysics Data System (ADS)

    Nakano, M.; Hikosaka, Y.; Lablanquie, P.; Penent, F.; Huttula, S.-M.; Suzuki, I. H.; Soejima, K.; Kouchi, N.; Ito, K.

    2012-04-01

    The Auger decay channels of the Ar 2p satellite states have been investigated using a multielectron coincidence technique, using a magnetic bottle time-of-flight electron spectrometer. For the Ar+(2p-13p-1np) satellite states the 2p hole is filled first, while for the Ar+(2p-13s-14s) satellite states the 3s hole is filled first with leading to Ar2+(2p-13p-1) states, which subsequently undergo an Auger decay leading to the filling of the 2p hole.

  11. Experimental Determination of the Dominant Type of Auger Recombination in InGaN Quantum Wells

    NASA Astrophysics Data System (ADS)

    Galler, Bastian; Lugauer, Hans-Jürgen; Binder, Michael; Hollweck, Richard; Folwill, Yannick; Nirschl, Anna; Gomez-Iglesias, Alvaro; Hahn, Berthold; Wagner, Joachim; Sabathil, Matthias

    2013-11-01

    We investigate theoretically the influence of type and density of background carriers in the active region on the quantum efficiency of InGaN-based light emitters using an extension of the ABC rate model. A method to determine experimentally whether a certain type of Auger recombination is relevant in InGaN quantum wells is derived from these considerations. Using this approach, we show that the physical process which is the dominant cause for the efficiency droop is superlinear in the electron density and can thus be assigned to nnp-Auger recombination.

  12. Effects of the atomic level shift in the Auger neutralization rates of noble metal surfaces

    PubMed Central

    Monreal, R.C.; Goebl, D.; Primetzhofer, D.; Bauer, P.

    2013-01-01

    In this work we compare characteristics of Auger neutralization of He+ ions at noble metal and free-electron metal surfaces. For noble metals, we find that the position of the energy level of He with respect to the Fermi level has a non-negligible influence on the values of the calculated Auger rates through the evaluation of the surface dielectric susceptibility. We conclude that even though our calculated rates are accurate, further theoretical effort is needed to obtain realistic values of the energy level of He in front of these surfaces. PMID:25843996

  13. Latest results from the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Lhenry-Yvon, Isabelle

    2016-07-01

    The Pierre Auger Observatory has been designed to investigate the origin and nature of Ultra High Energy Cosmic Rays (UHECR) with energies from 1017 to 1020 eV. In this paper we will review some of the most recent results obtained from data of the Pierre Auger Observatory, namely the spectrum of cosmic rays, the anisotropies in arrival directions and the studies related to mass composition and to the number of muons measured at the ground. We will also discuss the implication of these results for assembling a consistent description of the composition, origin and propagation of cosmic rays.

  14. Auger anchors produce major cost savings

    SciTech Connect

    Webb, B.C.

    1981-10-01

    To meet specific-gravity standards, a 42-in.-diam, 0.598-in.-wall-thickness pipeline being installed in a glacial area full of potholes, peat swamps, and low-lying sections required 425 lb/ft of anchor hold-down. In spots where the underlying soil had an acceptable shear strength, the crew installed auger anchors (costing only $8/ft of pipeline) instead of the concrete set-on weights (at $80/ft) required in areas where the auger anchors would not hold; the savings amounted to about $380,000/mile of line laid.

  15. Electron Microscopy Localization and Characterization of Functionalized Composite Organic-Inorganic SERS Nanoparticles on Leukemia Cells

    PubMed Central

    Koh, Ai Leen; Shachaf, Catherine M.; Elchuri, Sailaja; Nolan, Garry P.; Sinclair, Robert

    2008-01-01

    We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet Scanning Electron Microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron detector (BSE) was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution Transmission Electron Microscope (TEM) images and Scanning Auger Electron Spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens. PMID:18995965

  16. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  17. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  18. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  19. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  20. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  1. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  2. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  3. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  4. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  5. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  6. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  7. 30 CFR 77.1505 - Auger holes; blocking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auger holes; blocking. 77.1505 Section 77.1505 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... § 77.1505 Auger holes; blocking. Auger holes shall be blocked with highwall spoil or other...

  8. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  9. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Hydrologic balance. 819.15 Section 819.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted...

  10. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§...

  11. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§...

  12. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§...

  13. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§...

  14. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  15. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  16. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  17. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  18. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining... against any hazard to underground workings located at or near such auger operations and all auger holes... underground mine; (b) Inundation hazards from surface water entering any active underground mine; (c)...

  19. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining... against any hazard to underground workings located at or near such auger operations and all auger holes... underground mine; (b) Inundation hazards from surface water entering any active underground mine; (c)...

  20. Proof of principal for staircase auger chip removal theory

    NASA Technical Reports Server (NTRS)

    Barron, Jeffrey B.; Brewer, Steve; Kerns, Kenneth; Moody, Kyle; Rossi, Richard A.

    1987-01-01

    A proof of principal design of the staircase auger theory is provided for lunar drilling. The drill is designed to drill holes 30 meters deep and 0.1 meters in diameter. The action of the auger is 0.01 meter strokes at a varying number of strokes per second. A detailed analysis of the interaction of the auger and particle was done to optimize the parameters of the auger. This optimum design will allow for proper heat removal and reasonable drilling time. The drill bit is designed to scoop the particles into the auger while efficiently cutting through the moon's surface.

  1. Measurement of sub-10 fs Auger processes in monolayer graphene.

    PubMed

    Giovanni, David; Yu, Guannan; Xing, Guichuan; Leek, Meng Lee; Sum, Tze Chien

    2015-08-10

    Despite the concerted efforts to directly probe the electron-electron (e-e) scattering mediated relaxation process in graphene using transient absorption spectroscopy, the initial sub-10 fs photoexcited carrier relaxation dynamics has remained elusive. Herein, we utilize a simple z-scan approach to elucidate this process and discern its mechanisms in CVD grown single layer graphene using femtosecond laser pulses with temporal pulse widths far longer than the relaxation time. We report the first experimental observation of e-e scattering lifetime shortening with increasing fluence, which had been theoretically predicted. Analysis from two-body Coulombic scattering suggests that Auger processes are essential relaxation channels in single layer graphene. Importantly, our straightforward approach on the graphene model system is applicable to the family of emergent layered materials. PMID:26367961

  2. Analysis of submicron defects using an SEM-Auger defect review tool

    SciTech Connect

    Childs, Kenton D.; Watson, David G.; Paul, Dennis F.; Clough, Stephen P.

    1998-11-24

    The challenges associated with analyzing semiconductor defects become greater as the device design rule decreases. According to the SIA National Technology Roadmap for Semiconductors, the current metrology requirement for particle analysis is 90 nm with the need to analyze 75 nm particles by the year 2001. These dimensional requirements are beyond the typical capabilities of current SEM/EDX defect review tools. Auger Electron Spectroscopy is a powerful method for measuring the surface composition of localized regions, and has been identified in the SIA roadmap as a primary technique for particle analysis. The ability of a state-of-the-art Auger defect review tool (DRT) to provide secondary electron and high spatial resolution elemental images is particularly effective in characterizing the often complex structure of semiconductor defects. Examples of Auger analysis from defects found at various process steps, on both unpatterned and patterned whole wafers, are shown. These examples highlight the ability of Auger to analyze both thin and laterally small or complex defects.

  3. Studies of signal waveforms from the water-cherenkov detectors of the Pierre Auger Observatory

    SciTech Connect

    Allison, P.S.; Bui-Duc, H.; Chye, J.; Dagoret-Campagne, S.; Dorofeev, A.; Matthews, J.; Nitz, D.F.; Ranchon, S.; Urban, M.; Veberic, D.; Watson, A.A.; Wileman, C.

    2005-08-01

    The ground array of the Pierre Auger Observatory will consist of 1600 water-Cherenkov detectors. Such detectors give signals which can help differentiate between muons and electrons in extensive air showers. The relative numbers of muons and electrons is sensitive to the type of primary particle which initiated the shower. Results are presented using methods which describe the muon content and related information, such as the time structure of the shower front.

  4. Clinical epidemiology of human AE in Europe.

    PubMed

    Vuitton, D A; Demonmerot, F; Knapp, J; Richou, C; Grenouillet, F; Chauchet, A; Vuitton, L; Bresson-Hadni, S; Millon, L

    2015-10-30

    This review gives a critical update of the situation regarding alveolar echinococcosis (AE) in Europe in humans, based on existing publications and on findings of national and European surveillance systems. All sources point to an increase in human cases of AE in the "historic endemic areas" of Europe, namely Germany, Switzerland, Austria and France and to the emergence of human cases in countries where the disease had never been recognised until the end of the 20th century, especially in central-eastern and Baltic countries. Both increase and emergence could be only due to methodological biases; this point is discussed in the review. One explanation may be given by changes in the animal reservoir of the parasite, Echinococcus multilocularis (increase in the global population of foxes in Europe and its urbanisation, as well as a possible increased involvement of pet animals as definitive infectious hosts). The review also focuses onto 2 more original approaches: (1) how changes in therapeutic attitudes toward malignant and chronic inflammatory diseases may affect the epidemiology of AE in the future in Europe, since a recent survey of such cases in France showed the emergence of AE in patients with immune suppression since the beginning of the 21st century; (2) how setting a network of referral centres in Europe based on common studies on the care management of patients might contribute to a better knowledge of AE epidemiology in the future. PMID:26346900

  5. Recent results from the Pierre Auger Observatory

    SciTech Connect

    Gascón, Alberto; Collaboration: Pierre Auger Collaboration

    2014-07-23

    The Pierre Auger Observatory has been designed to investigate the origin and nature of Ultra High Energy Cosmic Rays (UHECR) using a hybrid detection technique. In this contribution we present some of the most recent results of the observatory, namely the upper-end of the spectrum of cosmic rays, state-of-the-art analyses on mass composition, the measurements of the proton-air cross-section, and the number of muons at ground.

  6. Intersubband Auger recombination and population inversion in quantum-well subbands

    NASA Technical Reports Server (NTRS)

    Borenstain, S.; Katz, J.

    1989-01-01

    The intersubband-Auger-recombination time of electrons under population-inversion conditions in a single quantum well is calculated by taking into account momentum- and energy-conservation rules, and by employing Fermi-Dirac statistics. The screened matrix element of the electron-electron interaction and the overlap integral are calculated for an infinitely deep quantum well. The results are in a good agreement with published experimental data. As a major nonradiative process, the Auger recombination is related to threshold current of infrared lasers based on intersubband transitions in quantum-well structures. The realization of these devices and other limitations to achieving population inversion are discussed. In view of the results, development of these lasers for emission wavelengths corresponding to energies below the LO-phonon energy seems feasible.

  7. Distributed Computing for the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Chudoba, J.

    2015-12-01

    Pierre Auger Observatory operates the largest system of detectors for ultra-high energy cosmic ray measurements. Comparison of theoretical models of interactions with recorded data requires thousands of computing cores for Monte Carlo simulations. Since 2007 distributed resources connected via EGI grid are successfully used. The first and the second versions of production system based on bash scripts and MySQL database were able to submit jobs to all reliable sites supporting Virtual Organization auger. For many years VO auger belongs to top ten of EGI users based on the total used computing time. Migration of the production system to DIRAC interware started in 2014. Pilot jobs improve efficiency of computing jobs and eliminate problems with small and less reliable sites used for the bulk production. The new system has also possibility to use available resources in clouds. Dirac File Catalog replaced LFC for new files, which are organized in datasets defined via metadata. CVMFS is used for software distribution since 2014. In the presentation we give a comparison of the old and the new production system and report the experience on migrating to the new system.

  8. On the uncertainty of the Auger recombination coefficient extracted from InGaN/GaN light-emitting diode efficiency droop measurements

    SciTech Connect

    Piprek, Joachim; Römer, Friedhard; Witzigmann, Bernd

    2015-03-09

    III-nitride light-emitting diodes (LEDs) suffer from a severe efficiency reduction with increasing injection current (droop). Auger recombination is often seen as primary cause of this droop phenomenon. The corresponding Auger recombination coefficient C is typically obtained from efficiency measurements using mathematical models. However, C coefficients reported for InGaN active layers vary over two orders of magnitude. We here investigate this uncertainty and apply successively more accurate models to the same efficiency measurement, thereby revealing the strong sensitivity of the Auger coefficient to quantum well properties such as electron-hole ratio, electric field, and hot carrier escape.

  9. On the uncertainty of the Auger recombination coefficient extracted from InGaN/GaN light-emitting diode efficiency droop measurements

    NASA Astrophysics Data System (ADS)

    Piprek, Joachim; Römer, Friedhard; Witzigmann, Bernd

    2015-03-01

    III-nitride light-emitting diodes (LEDs) suffer from a severe efficiency reduction with increasing injection current (droop). Auger recombination is often seen as primary cause of this droop phenomenon. The corresponding Auger recombination coefficient C is typically obtained from efficiency measurements using mathematical models. However, C coefficients reported for InGaN active layers vary over two orders of magnitude. We here investigate this uncertainty and apply successively more accurate models to the same efficiency measurement, thereby revealing the strong sensitivity of the Auger coefficient to quantum well properties such as electron-hole ratio, electric field, and hot carrier escape.

  10. The accretion column of AE Aqr

    NASA Astrophysics Data System (ADS)

    Rodrigues, Claudia; Costa, D. Joaquim; Luna, Gerardo; Lima, Isabel J.; Silva, Karleyne M. G.; De Araujo, Jose Carlos N.; Coelho, Jaziel

    2016-07-01

    AE Aqr is a magnetic cataclysmic variable, whose white dwarf rotates at the very fast rate of 33 s modulating the flux from high-energies to optical wavelengths. There are many studies of the origin of its emission, which consider emission from a rotating magnetic field or from an accretion column. Recently, MAGIC observations have discarded AE Aqr emission in very high energy gamma-rays discarding non-thermal emission. Furthermore, soft and hard X-ray data from Swift and NuSTAR were fitted using thermal models. Here we present the modelling of AE Aqr X-ray spectra and light curve considering the emission of a magnetic accretion column using the Cyclops code. The model takes into consideration the 3D geometry of the system, allowing to properly represent the white-dwarf auto eclipse, the pre-shock column absorption, and the varying density and temperature of a tall accretion column.

  11. Thermal activation of non-radiative Auger recombination in charged colloidal nanocrystals.

    PubMed

    Javaux, C; Mahler, B; Dubertret, B; Shabaev, A; Rodina, A V; Efros, Al L; Yakovlev, D R; Liu, F; Bayer, M; Camps, G; Biadala, L; Buil, S; Quelin, X; Hermier, J-P

    2013-03-01

    Applications of semiconductor nanocrystals such as biomarkers and light-emitting optoelectronic devices require that their fluorescence quantum yield be close to 100%. However, such quantum yields have not been obtained yet, in part, because non-radiative Auger recombination in charged nanocrystals could not be suppressed completely. Here, we synthesize colloidal core/thick-shell CdSe/CdS nanocrystals with 100% quantum yield and completely quenched Auger processes at low temperatures, although the nanocrystals are negatively photocharged. Single particle and ensemble spectroscopy in the temperature range 30-300 K shows that the non-radiative Auger recombination is thermally activated around 200 K. Experimental results are well described by a model suggesting a temperature-dependent delocalization of one of the trion electrons from the CdSe core and enhanced Auger recombination at the abrupt CdS outer surface. These results point to a route for the design of core/shell structures with 100% quantum yield at room temperature. PMID:23396313

  12. Postcollision interactions in the Auger decay of the Ar L-shell

    SciTech Connect

    Samson, J.A.R.; Stolte, W.C.; He, Z.X.

    1997-04-01

    The photoionization cross sections for Ar{sup +} through Ar{sup 4+}, produced by the Auger decay of an inner shell 2p hole, have been measured between 242 eV and 253 eV on beamline 9.0.1 and 6.3.2. In this study the authors are interested in near threshold phenomenon involving postcollision interactions (PCI), which are related to the Auger decay of a vacancy in the Ar L-shell. During an Auger decay a postcollision interaction can occur causing the out-going photoelectron to be retarded thus losing a certain amount of energy. If the retardation is sufficiently large the photoelectron will not escape. This result produces a singly charged ion, which normally would not be present. Such evidence of electron capture by the PCI effect was first shown clearly by Eberhardt et al. and, with higher resolution, in the present work. However, capture of the photoelectron is expected to be 100% exactly at the L{sub 2,3} thresholds. Thus, from the authors results they would have expected the Ar{sup 2+} signal to be zero at threshold, but it was not? The authors can explain this anomoly on the basis that during the Auger decay the photoelectrons are captured into high lying excited states of Ar{sup +}, which subsequently decay through autoionization yielding Ar{sup 2+}. Future work in this area will seek experimental evidence to verify this prediction.

  13. Differential attack on mini-AES

    NASA Astrophysics Data System (ADS)

    Ajeng Gemellia, Asadini Dwi; Indarjani, Santi

    2012-05-01

    This paper presents the results of differential attack on Mini-AES algorithm. The differential trails are constructed using all combinations of propagation ratio without repetition. To give practical results, we implement the key extraction for differential characteristics which have the highest and lowest probability as a comparison. Based on total propagation ratio and complexity resulted, Mini-AES algorithms are vulnerable to differential attack. The best differential characteristic is the differential characteristic using a single active s-box with the propagation ratio of 8 / 16.

  14. Auger mediated positron sticking on graphene and highly oriented pyrolytic graphite

    NASA Astrophysics Data System (ADS)

    Chirayath, V. A.; Chrysler, M.; McDonald, A.; Lim, Z.; Shastry, K.; Gladen, R.; Fairchild, A.; Koymen, A.; Weiss, A.

    Positron annihilation induced Auger electron spectroscopy (PAES) measurements on 6-8 layers graphene grown on polycrystalline copper and the measurements on a highly oriented pyrolytic graphite (HOPG) sample have indicated the presence of a bound surface state for positrons. Measurements carried out with positrons of kinetic energies lower than the electron work function for graphene or HOPG have shown emission of low energy electrons possible only through the Auger mediated positron sticking (AMPS) process. In this process the positron makes a transition from a positive energy scattering state to a bound surface state. The transition energy is coupled to a valence electron which may then have enough energy to get ejected from the sample surface. The positrons which are bound to surface state are highly localized in a direction perpendicular to surface and delocalized parallel to it which makes this process highly surface sensitive and can thus be used for characterizing graphene or graphite surfaces for open volume defects and surface impurities. The measurements have also shown an extremely large low energy tail for the C KVV Auger transition at 263eV indicative of another physical process for low energy emission. This work was supported by NSF Grant No. DMR 1508719 and DMR 1338130.

  15. Matt Rogers on AES Energy Storage

    SciTech Connect

    Rogers, Matt

    2010-01-01

    The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

  16. Matt Rogers on AES Energy Storage

    ScienceCinema

    Rogers, Matt

    2013-05-29

    The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

  17. High-resolution Surface Analysis by Microarea Auger Spectroscopy: Computerization and Characterization

    NASA Technical Reports Server (NTRS)

    Browning, R.

    1986-01-01

    A custom scanning Auger electron microscope (SAM) capable of introducing a 3-5 keV electron beam of several nA into a 30 nm diameter sample area was fitted with a sample introduction system and was fully computerized to be used for materials science research. The method of multispectral Auger imaging was devised and implemented. The instrument was applied to various problems in materials science, including the study of the fiber/matrix interface in a SiC reinforced titanium alloy, the study of SiC whiskers in Al alloy 2124 (in cooperation with NASA-Langley), the study of NiCrAl superalloys (in collaboration with NASA-Lewis), the study of zircalloy specimens (in collaboration with Stanford University), and the microstructure of sintered SiC specimens (in collaboration with NASA-Lewis). The report contains a number of manuscripts submitted for publication on these subjects.

  18. Experimental and theoretical study of 3p photoionization and subsequent Auger decay in atomic chromium

    NASA Astrophysics Data System (ADS)

    Keskinen, J.; Huttula, S.-M.; Mäkinen, A.; Patanen, M.; Huttula, M.

    2015-12-01

    3p photoionization and subsequent low kinetic energy Coster-Kronig and super Coster-Kronig Auger decay have been studied in atomic chromium. The binding energies, line widths, and relative intensities for the transitions seen in the synchrotron radiation excited 3p photoelectron spectrum are determined. The high resolution M2,3 M4,5 M4,5 and M2,3 M4,5 N1 Auger electron spectra following the electron impact excited 3p ionization are presented and the kinetic energies, relative intensities, and identifications are given for the main lines. The experimental findings are compared with the theoretical predictions obtained from Hartree-Fock and multiconfiguration Dirac-Fock approaches.

  19. Auger Radiopharmaceutical Therapy Targeting Prostate-Specific Membrane Antigen

    PubMed Central

    Kiess, Ana P.; Hobbs, Robert; Sgouros, George; Mease, Ronnie C.; Pullambhatla, Mrudula; Shen, Colette J.; Foss, Catherine A.; Pomper, Martin G.

    2015-01-01

    Auger electron emitters such as 125I have a high linear energy transfer and short range of emission (<10 μm), making them suitable for treating micrometastases while sparing normal tissues. We used a highly specific small molecule targeting the prostate-specific membrane antigen (PSMA) to deliver 125I to prostate cancer cells. Methods The PSMA-targeting Auger emitter 2-[3-[1-carboxy-5-(4-125I-iodo-benzoylamino)-pentyl]-ureido]-pentanedioic acid (125I-DCIBzL) was synthesized. DNA damage (via phosphorylated H2A histone family member X staining) and clonogenic survival were tested in PSMA-positive (PSMA+) PC3 PIP and PSMA-negative (PSMA−) PC3 flu human prostate cancer cells after treatment with 125I-DCIBzL. Subcellular drug distribution was assessed with confocal microscopy using a related fluorescent PSMA-targeting compound YC-36. In vivo antitumor efficacy was tested in nude mice bearing PSMA+ PC3 PIP or PSMA− PC3 flu flank xenografts. Animals were administered (intravenously) 111 MBq (3 mCi) of 125I-DCIBzL, 111 MBq (3 mCi) of 125I-NaI, an equivalent amount of nonradiolabeled DCIBzL, or saline. Results After treatment with 125I-DCIBzL, PSMA+ PC3 PIP cells exhibited increased DNA damage and decreased clonogenic survival when compared with PSMA− PC3 flu cells. Confocal microscopy of YC-36 showed drug distribution in the perinuclear area and plasma membrane. Animals bearing PSMA+ PC3 PIP tumors had significant tumor growth delay after treatment with 125I-DCIBzL, with only 1 mouse reaching 5 times the initial tumor volume by 60 d after treatment, compared with a median time to 5 times volume of less than 15 d for PSMA− PC3 flu tumors and all other treatment groups (P = 0.002 by log-rank test). Conclusion PSMA-targeted radiopharmaceutical therapy with the Auger emitter 125I-DCIBzL yielded highly specific antitumor efficacy in vivo, suggesting promise for treatment of prostate cancer micrometastases. PMID:26182968

  20. Magnetic fields in Herbig Ae stars

    NASA Astrophysics Data System (ADS)

    Hubrig, S.; Schöller, M.; Yudin, R. V.

    2004-12-01

    Herbig Ae stars are young A-type stars in the pre-main sequence evolutionary phase with masses of ˜1.5-3 M⊙. They show rather intense surface activity (Dunkin et al. \\cite{Du97}, MNRAS, 290, 165) and infrared excess related to the presence of circumstellar disks. Because of their youth, primordial magnetic fields inherited from the parent molecular cloud may be expected, but no direct evidence for the presence of magnetic fields on their surface, except in one case (Donati et al. \\cite{Do97}, MNRAS, 291, 658), has been found until now. Here we report observations of optical circular polarization with FORS 1 at the VLT in the three Herbig Ae stars HD 139614, HD 144432 and HD 144668. A definite longitudinal magnetic field at 4.8 σ level, =-450±93 G, has been detected in the Herbig Ae star HD 139614. This is the largest magnetic field ever diagnosed for a Herbig Ae star. A hint of a weak magnetic field is found in the other two Herbig Ae stars, HD 144432 and HD 144668, for which magnetic fields are measured at the ˜1.6 σ and ˜2.5 σ level respectively. Further, we report the presence of circular polarization signatures in the Ca II K line in the V Stokes spectra of HD 139614 and HD 144432, which appear unresolved at the low spectral resolution achievable with FORS 1. We suggest that models involving accretion of matter from the disk to the star along a global stellar magnetic field of a specific geometry can account for the observed Zeeman signatures. Based on observations obtained at the European Southern Observatory, Paranal, Chile (ESO programme No. 072.D-0377).

  1. The Pierre Auger Project: an overview

    NASA Astrophysics Data System (ADS)

    Mantsch, Paul M.

    2003-02-01

    The Southern Hemisphere site of the Pierre Auger Observatory is now under construction in Argentina by a collaboration of 50 institutions in 16 countries. The objective of the Auger Project is to make a high statistics measurement of cosmic rays above 1019 eV. The observatory will record extensive air showers induced by these cosmic rays incident on the atmosphere. The measurement will include energy, direction and composition of the primary particles. The engineering phase is now complete and full construction has begun. The search for the source of the highest energy cosmic rays is one of the most interesting problems in astrophysics. Following the discovery of the cosmic microwave background, Greisen and, independently, Zatsepin and Kuzmin realized hat this background radiation would make space opaque to cosmic rays of very high energy. Nevertheless over the past 30 years several tens of events were recorded with energies above the Greisen, Zatsepin, Kuzmin (GZK) cutoff (about 5×1019 eV) including a number above 1020 eV. These events present a conundrum. Because of the GZK cut off these super high-energy events must come from nearby, less than about 50 Mpc. In addition the cosmic acceleration mechanism for achieving these energies is very difficult to conceive. Yet, even though particles of these energies are only slightly deflected by galactic and extragalactic magnetic fields, none clearly points back to a source sufficiently violent to a be a candidate source. The Auger Observatory finished its engineering development phase at the end of 2001. The "Engineering Array" consists of 40 surface particle detector stations and two prototype air fluorescence telescopes. The Observatory, when complete, will have a 1600 detector surface array covering 3000 km**2 overlooked by 24 fluorescence telescopes. The Engineering Array has demonstrated that all of the detector systems perform as well or better than expected. Recently the Observatory has recorded a number of

  2. Auger tension leg platform cathodic protection system

    SciTech Connect

    Goolsby, A.D.; Smith, J.D.

    1995-11-01

    In 1986, Shell began investigating corrosion control systems for a generic 3,000 ft. water depth Tension Leg Platform (TLP) type structure to be located in the north-central Gulf of Mexico. In 1987, the 2,850 ft. deep Garden Banks block 426 ``Auger`` location was chosen for the first TLP, and the detailed design process began in earnest. During late 1993 and early 1994, the Auger hull was mated with the other components at its permanent site, and first oil and gas production began April 15, 1994. This paper describes the corrosion control design for the exterior submerged and buried steel surfaces of the 2,850 ft. (869 m) water depth Auger Tension Leg Platform structure. Each major type of component (hull, subsea marine wellhead/guidebase, tendon foundation template, tendon, and production riser) has its own combination of coating system and cathodic protection system designed for a thirty five year lifetime. Cathodic protection (CP) is achieved using a variety of sacrificial anode alloys and geometries (e.g. bracelet, flush-mount, and standoff anodes). Anode and cathode CP design parameters for each component depend upon water depth, and were developed using field test data, laboratory studies, field measurements on existing structures, and available literature information. CP design was performed using design spreadsheets constructed for each component, which optimized anode geometries. Extensive quality assurance efforts were part of the anode procurement process, to ensure performance for the intended life of the corrosion-control systems. Results of early in-service CP surveys of the tendons and guidebases are presented, showing the successful achievement of cathodic protection against seawater corrosion. Corrosion control of one additional system, the eight point lateral mooring system, is not addressed here.

  3. Absolute calibration of the Auger fluorescence detectors

    SciTech Connect

    Bauleo, P.; Brack, J.; Garrard, L.; Harton, J.; Knapik, R.; Meyhandan, R.; Rovero, A.C.; Tamashiro, A.; Warner, D.

    2005-07-01

    Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.

  4. K-shell auger decay of atomic oxygen

    SciTech Connect

    Stolte, W.C.; Lu, Y.; Samson, J.A.R.

    1997-04-01

    The aim of the present research is to understand the interaction between the ejected photoelectron and Auger electron produced by the Auger decay of a 1s hole in atomic oxygen, and to understand the influence this interaction has on the shape of the ionization cross sections. To accomplish this the authors have measured the relative ion yields (ion/photon) in the vicinity of the oxygen K-shell (525 - 533 eV) for O{sup +} and O{sup 2+}. The measurements were performed at the ALS on beamline, 6.3.2. The atomic oxygen was produced by passing molecular oxygen through a microwave-driven discharge. A Rydberg analysis of the two series leading to the [1s]2s{sup 2}2p{sup 4}({sup 4}P) and [1s]2s{sup 2}2p{sup 4}({sup 2}P) limits were obtained. This analysis shows some differences to the recently published results by Menzel et al. The energy position of the main 1s{sup 1}2s{sup 2}2p{sup 5}({sup 3}P) resonance differs by approximately 1 eV from the authors value, all members of the ({sup 2}P)np series differ by 0.3 eV, but the members of the ({sup 4}P)np series agree. The molecular resonance at 530.5 eV and those between 539 eV and 543 eV, measured with the microwave discharge off show identical results in both experiments.

  5. Auger and radiative deexcitation of the 1s2l3l prime configurations of lithium-like neon

    NASA Technical Reports Server (NTRS)

    Chen, M. H.

    1976-01-01

    The three-electron configurations of 1s2lambda3lambda of neon are observed in ion-atom collisions and beam foil excitation. Multiplet Auger and x ray transition rates obtained in intermediate coupling are calculated. Fluorescence yields are also computed.

  6. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  7. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  8. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  9. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  10. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  11. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  12. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  13. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  14. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  15. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  16. Angular dependence of the auger lineshape of graphite

    SciTech Connect

    Rogers, J.W. Jr.; Houston, J.E.; Rye, R.R.

    1986-01-01

    The Auger lineshape of graphite is of interest as a model for studying initial-state, core-hole screening and final-state, hole-hole correlation effects in aromatic systems. We have obtained the Auger spectra from POCO (amorphous) and HOPG (highly-oriented pyrolytic) graphite.

  17. Education and public outreach of the Pierre Auger Observatory

    SciTech Connect

    Garcia, B.; Snow, G.

    2005-08-01

    The Auger collaboration's broad mission in education, outreach and public relations is coordinated in a separate task. Its goals are to encourage and support a wide range of outreach efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. This report focuses on recent activities and future initiatives.

  18. Chemisorption of Si on Al(111) surfaces: A local-chemical-bond analysis from Auger transition density of states

    NASA Astrophysics Data System (ADS)

    Muñoz, M. C.; Sacedón, J. L.; Soria, F.; Martinez, V.

    1986-07-01

    Auger and electron loss spectroscopies have been used to study the local chemical bond between Si and Al, in the first stages of growth of Si deposited at room temperature on Al(111) surfaces. Si follows a layer-by-layer mechanism up to 2 monolayers with the formation of an Al(111)-3 × 3-Si structure at about 0.44 monolayers. A detailed analysis of the L 2,3VV Auger spectra for this structure allows to interpret the Si and Al Auger transition density of states (TDOS) in terms of the actual p-like partial DOS centered on the Si and Al sites. The experimental results indicate a strong SiAl interaction with the formation of a p-type local covalent bond between the Si and Al surface atoms.

  19. Auger Stimulated Ion Desorption of Negative Ions via K -Capture Radioactive Decay

    SciTech Connect

    Verkhoturov, S. V.; Schweikert, E. A.; Chechik, Victor; Sabapathy, Rajaram C.; Crooks, Richard M.; Parilis, E. S.

    2001-07-16

    We report on Auger stimulated ion desorption via Coulomb explosion from surface self-assembled alkylthiol and fluorocarbon molecular layers, triggered by K -capture decay of an imbedded radioactive {sup 55}Fe atom. The charge state of the ejecta is determined by charge exchange in binary atomic collisions in bulk and electron tunneling outside the solid, as well as by fragmentation of electronically excited molecules or molecular fragments. We describe the first nonbeam experiments documenting positive and abundant negative ion desorption due solely to core electron excitation after radioactive decay.

  20. Auger-decay engineering in quantum dots in relation to applications in LEDs and lasers (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Klimov, Victor I.

    2015-09-01

    Multicarrier dynamics in colloidal quantum dots (QDs) are normally controlled by nonradiative Auger recombination wherein the energy of an electron-hole pair is converted not into a photon but instead transferred to a third carrier (an electron or a hole). Auger decay is extremely fast in QDs (time scales of tens-to-hundreds of picoseconds) due to both close proximity between interacting charges and elimination of restrictions imposed by translational momentum conservation. Photoluminescence (PL) quenching by nonradiative Auger processes complicates realization of applications that require high emissivity of multicarrier states such as light-emitting diodes (LEDs) and lasers. Therefore, the development of "Auger-recombination-free" QDs is an important current challenge in the field of colloidal nanostructures. Previous single-dot spectroscopic studies have indicated a significant spread in Auger lifetimes across an ensemble of nominally identical QDs. It has been speculated that in addition to dot-to-dot variation in physical dimensions, this spread is contributed to by variations in the structure of the QD interface, which controls the shape of the confinement potential. Here we directly evaluate the effect of the composition of the core-shell interface on single- and multi-exciton dynamics via side-by-side measurements of individual core-shell CdSe/CdS nanocrystals with a sharp vs. smooth (graded) interface. We observe that while having essentially no effect on single-exciton decay, the interfacial alloy layer leads to a systematic increase in the biexciton lifetime indicating suppression of Auger recombination. We demonstrate that using QDs with "engineered interfaces" we can considerably improve the performance of QD LEDs and lasers.

  1. Electronic properties and bonding characteristics of AlN:Ag thin film nanocomposites

    SciTech Connect

    Lekka, Ch. E.; Patsalas, P.; Komninou, Ph.; Evangelakis, G. A.

    2011-03-01

    We present theoretical and experimental results on the bonding and structural characteristics of AlN:Ag thin film nanocomposites obtained by means of density functional theory (DFT) computations, high resolution transmission electron microscopy (HRTEM) observations, Auger electron spectroscopy (AES), and x-ray diffraction (XRD) measurements. From the theoretical calculations it was determined that the presence of the Ag substitutional of N or Al atoms affects the electronic density of states (EDOS) of the resulting systems. In particular, occupied energy states are introduced (between others) that lie within the energy gap of the AlN matrix due to Ag-d, Al-p (accompanied with a charge transfer from Al to Ag), Ag-p, and N-p hybridizations, respectively. The effect is predicted to be even more pronounced in the case of Ag nanoparticle inclusions affecting the EDOS of the composite system. These predictions were verified by the HRTEM images that gave unequivocal evidence for the presence and stability of Ag nanoparticles in the AlN matrix. In addition, the AES data suggested a metal-metal (Ag-Al) bonding preference, while the XRD patterns revealed that the atomic Ag dispersions in the AlN thin films results in a small elongation of the Wurtzite lattice, which is in agreement with the DFT predictions. These results may useful in tailoring the electronic response of AlN-based systems and the design of devices for various opto-electronic applications.

  2. AES Water Architecture Study Interim Results

    NASA Technical Reports Server (NTRS)

    Sarguisingh, Miriam J.

    2012-01-01

    The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems in order to enable NASA human exploration missions beyond low earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near term missions beyond LEO. The secondary objective is to continue to advance mid-readiness level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near and long term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit environmental control and life support systems (ECLSS) definition. This study is being performed in three phases. Phase I of this study established the scope of the study through definition of the mission requirements and constraints, as well as indentifying all possible WRS configurations that meet the mission requirements. Phase II of this study focused on the near term space exploration objectives by establishing an ISS-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

  3. Numerical evaluation of Auger recombination coefficients in relaxed and strained germanium

    NASA Astrophysics Data System (ADS)

    Dominici, Stefano; Wen, Hanqing; Bertazzi, Francesco; Goano, Michele; Bellotti, Enrico

    2016-05-01

    The potential applications of germanium and its alloys in infrared silicon-based photonics have led to a renewed interest in their optical properties. In this letter, we report on the numerical determination of Auger coefficients at T = 300 K for relaxed and biaxially strained germanium. We use a Green's function based model that takes into account all relevant direct and phonon-assisted processes and perform calculations up to a strain level corresponding to the transition from indirect to direct energy gap. We have considered excess carrier concentrations ranging from 1016 cm-3 to 5 × 1019 cm-3. For use in device level simulations, we also provide fitting formulas for the calculated electron and hole Auger coefficients as functions of carrier density.

  4. 119Sb--a potent Auger emitter for targeted radionuclide therapy.

    PubMed

    Thisgaard, H; Jensen, M

    2008-09-01

    Auger electron emitting radionuclides in cancer therapy offer the opportunity to deliver a high radiation dose to the tumor cells with high radiotoxicity while minimizing toxicity to normal tissue. We have in this study identified the Auger emitter 119Sb as a potent nuclide for targeted radionuclide therapy based on theoretical dosimetry calculations at a subcellular scale. From these calculations we have determined the cellular S-values for this therapeutic isotope. Moreover, we have demonstrated the possibility of producing this isotope and also the SPECT-analogue 117Sb for patient-specific dosimetry, by measuring the proton irradiation yields for both isotopes using a low-energy cyclotron. The excellent SPECT imaging properties of the 117Sb radionuclide have been shown by scanning a Jaszczak SPECT Phantom. PMID:18841834

  5. Mechanisms of Auger-induced chemistry derived from wave packet dynamics.

    PubMed

    Su, Julius T; Goddard, William A

    2009-01-27

    To understand how core ionization and subsequent Auger decay lead to bond breaking in large systems, we simulate the wave packet dynamics of electrons in the hydrogenated diamond nanoparticle C(197)H(112). We find that surface core ionizations cause emission of carbon fragments and protons through a direct Auger mechanism, whereas deeper core ionizations cause hydrides to be emitted from the surface via remote heating, consistent with results from photon-stimulated desorption experiments [Hoffman A, Laikhtman A, (2006) J Phys Condens Mater 18:S1517-S1546]. This demonstrates that it is feasible to study the chemistry of highly excited large-scale systems using simulation and analysis tools comparable in simplicity to those used for classical molecular dynamics. PMID:19164568

  6. Mechanisms of Auger-induced chemistry derived from wave packet dynamics

    PubMed Central

    Su, Julius T.; Goddard, William A.

    2009-01-01

    To understand how core ionization and subsequent Auger decay lead to bond breaking in large systems, we simulate the wave packet dynamics of electrons in the hydrogenated diamond nanoparticle C197H112. We find that surface core ionizations cause emission of carbon fragments and protons through a direct Auger mechanism, whereas deeper core ionizations cause hydrides to be emitted from the surface via remote heating, consistent with results from photon-stimulated desorption experiments [Hoffman A, Laikhtman A, (2006) J Phys Condens Mater 18:S1517–S1546]. This demonstrates that it is feasible to study the chemistry of highly excited large-scale systems using simulation and analysis tools comparable in simplicity to those used for classical molecular dynamics. PMID:19164568

  7. Inter-Coulombic decay (ICD) of endofullerene inner-vacancies in coherence with the Auger decay

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, Maia; de, Ruma; Javani, Mohammad; Madjet, Mohamed; Manson, Steven T.; Chakraborty, Himadri

    2016-05-01

    For an endohedrally confined atom in a fullerene, an innershell vacancy created either in the atom or the fullerene can decay through the continuum of an outer electron hybridized between the systems. Such decays, which can be viewed as coherent superpositions of the single-center Auger and two-center inter-Coulombic (ICD) amplitudes, are found to govern leading decay mechanisms in endofullerenes. Resonances calculated by the method of time-dependent local density approximation (TDLDA) in the photoionization of noble gas endofullerenes show details of the underlying processes. These resonances are found to be significantly stronger than both regular ICD and Auger resonances, which make them well amenable for experimental detection. The work is supported by US NSF and DOE, Basic Energy Sciences.

  8. {sup 119}Sb--A potent Auger emitter for targeted radionuclide therapy

    SciTech Connect

    Thisgaard, H.; Jensen, M.

    2008-09-15

    Auger electron emitting radionuclides in cancer therapy offer the opportunity to deliver a high radiation dose to the tumor cells with high radiotoxicity while minimizing toxicity to normal tissue. We have in this study identified the Auger emitter {sup 119}Sb as a potent nuclide for targeted radionuclide therapy based on theoretical dosimetry calculations at a subcellular scale. From these calculations we have determined the cellular S-values for this therapeutic isotope. Moreover, we have demonstrated the possibility of producing this isotope and also the SPECT-analogue {sup 117}Sb for patient-specific dosimetry, by measuring the proton irradiation yields for both isotopes using a low-energy cyclotron. The excellent SPECT imaging properties of the {sup 117}Sb radionuclide have been shown by scanning a Jaszczak SPECT Phantom.

  9. Theoretical prediction of the impact of Auger recombination on charge collection from an ion track

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1991-01-01

    A recombination mechanism that significantly reduces charge collection from very dense ion tracks in silicon devices was postulated by Zoutendyk et al. The theoretical analysis presented here concludes that Auger recombination is such a mechanism and is of marginal importance for higher density tracks produced by 270-MeV krypton, but of major importance for higher density tracks. The analysis shows that recombination loss is profoundly affected by track diffusion. As the track diffuses, the density and recombination rate decrease so fast that the linear density (number of electron-hole pairs per unit length) approaches a non-zero limiting value as t yields infinity. Furthermore, the linear density is very nearly equal to this limiting value in a few picoseconds or less. When Auger recombination accompanies charge transport processes that have much longer time scales, it can be simulated by assigning a reduced linear energy transfer to the ion.

  10. Theoretical prediction of the impact of Auger recombination on charge collection from an ion track

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1991-01-01

    The theoretical analysis presented indicates that Auger recombination can reduce charge collection from very dense ion tracks in silicon devices. It is of marginal importance for tracks produced by 270-MeV krypton, and therefore it is of major importance for ions exhibiting a significantly larger loss. The analysis shows that recombination loss is profoundly affected by track diffusion. As the track diffuses, the density and recombination rate decrease so fast that the linear density (number of electron-hole pairs per unit length) approaches a nonzero limiting value as t approaches infinity. Furthermore, the linear density is very nearly equal to this limiting value in a few picoseconds or less. When Auger recombination accompanies charge transport processes that have much longer time scales, it can be simulated by assigning a reduced linear energy transfer to the ion.

  11. Core-shell resonant Auger-decay induced fragmentation of glycine molecule

    NASA Astrophysics Data System (ADS)

    Fang, Li; Xiong, Hui; Osipov, Timur; Petrovic, Vladimir; Guehre, Markus; Berrah, Nora

    2015-05-01

    We investigated the fragmentation of glycine molecular ions induced by resonant Auger decay with synchrotron light source. We measured the charge distribution and the kinetic energies of various fragment ions with photon energies at the oxygen and the carbon 1s electron excitation resonance, as well as at photon energies above the K-edge of the oxygen and carbon atoms. We studied the fragmentation pathways using ion-ion coincidence measurement with a velocity map imaging spectrometer. We observed closure of certain fragmentation pathways at the on-resonance photon energy and the opening-up of certain fragmentation pathways by ionization of certain atomic sites. We will present that resonant Auger leads to unique dissociation patterns. Department of Energy, Office of Science, Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under grant N. DE-FG02-92ER14299.A002 and in part by the National Science Foundation under Grant No. 1404109.

  12. 22 CFR 120.30 - The Automated Export System (AES).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false The Automated Export System (AES). 120.30... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of... data and defense services shall be reported directly to the Directorate of Defense Trade Controls...

  13. 22 CFR 120.30 - The Automated Export System (AES).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false The Automated Export System (AES). 120.30... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of... data and defense services shall be reported directly to the Directorate of Defense Trade Controls...

  14. 22 CFR 120.30 - The Automated Export System (AES).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false The Automated Export System (AES). 120.30... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of... data and defense services shall be reported directly to the Directorate of Defense Trade Controls...

  15. 22 CFR 120.30 - The Automated Export System (AES).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false The Automated Export System (AES). 120.30... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of... data and defense services shall be reported directly to the Directorate of Defense Trade Controls...

  16. 22 CFR 120.30 - The Automated Export System (AES).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false The Automated Export System (AES). 120.30... DEFINITIONS § 120.30 The Automated Export System (AES). The Automated Export System (AES) is the Department of... data and defense services shall be reported directly to the Directorate of Defense Trade Controls...

  17. XPS, AES and SEM analysis of recent dental implants.

    PubMed

    Kang, Byung-Soo; Sul, Young-Taeg; Oh, Se-Jung; Lee, Hyun-Ju; Albrektsson, Tomas

    2009-07-01

    Today, surface chemistry modifications of titanium implants have become a development strategy for dental implants. The present study investigated the chemistry and morphology of commercially available dental implants (Nobel biocare TiUnite, Astra AB OsseoSpeed, 3i Osseotite, ITI-SLA). X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy were employed for the analysis of surface chemistry. The morphology was investigated by scanning electron microscopy. The present study demonstrated the major differences of surface properties, mainly dependent on the surface treatment used. The blasting and acid etching technique for the OsseoSpeed, Osseotite and SLA surfaces generally showed mainly TiO(2), but a varying surface morphology. In contrast, the electrochemical oxidation process for TiUnite implants not only produces microporous surface (pore size: 0.5-3.0microm), but also changes surface chemistry due to incorporation of anions of the used electrolyte. As a result, TiUnite implants contain more than 7at.% of P in oxide layer and higher amounts of hydroxides compared to the other implants in XPS analysis. F in OsseoSpeed implants was detected at 0.3% before as well as after sputter cleaning. PMID:19261554

  18. Soil chip convey of lunar subsurface auger drill

    NASA Astrophysics Data System (ADS)

    Zhao, Deming; Tang, Dewei; Hou, Xuyan; Jiang, Shengyuan; Deng, Zongquan

    2016-05-01

    Celestial body subsurface drilling and sampling is a key aspect of near-earth exploration projects. In these sample return missions, the auger drill system is universally used due to the environment and detector load limits. The common failure that the auger faces is chip chocking, which can raise the torque and cause the drill to stick. This paper builds auger drill models describing chip flow in the auger groove to balance geometric parameters, functional capability, and reliability. The features of chip flow are summarized and verified by a series of discrete element method simulations. In contrast to previous auger design, a convey capability factor is defined to indicate the auger's chip removal capacity, and the role of pitch angle and other parameters is assessed through motion analysis of the lunar soil flow process. The theory is verified by testing the drill penetrating speed limit, which combines drill geometry and motion parameters. This work provides a new method for design and optimization of low speed auger drill systems and research on particle flow with small scale mechanical constraints.

  19. Latest results from the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Dembinski, Hans P.; Pierre Auger Collaboration

    2012-02-01

    The Pierre Auger Observatory, located in the Province of Mendoza, Argentina, is the World's largest detector for cosmic rays at ultra-high energies. In its seven years of operation it has collected an exposure of more than 20000 km2 sr yr, larger than all previous experiments combined. Its original design, optimized for the energy range 1018 eV to 1020 eV, is currently enhanced to cover energies down to almost 1017 eV. We give an overview of the latest results with a focus on the prospect to study nuclear interactions with cosmic rays and conclude with a brief outlook on developments and extensions of the observatory. Full author list

  20. Current Status of the Pierre Auger Project

    NASA Astrophysics Data System (ADS)

    Etchegoyen, A.

    The Pierre Auger Project aims at building two Observatories in order to study ultra high energy cosmic rays, situated in both northern and southern hemispheres. In 2000 started the construction of the austral observatory. Prior to this, in 1995, the international collaboration was formed encompassing 200 scientists and technicians from institutions in 16 countries. The Auger Project is a basic science enterprise which studies the highest energies known in nature ( 1020 eV) , which are cosmic rays coming from the outer space arriving to the earth surface with at a very reduced flow. This is the reason for constructing a giant observatory spanning an area of 3000 km2 in the department of Malargüe and San Rafael, in the Province of Mendoza. Other distinctive feature, besides the exceptional size of the Observatory, is its hybrid nature: it is constituted by 24 fluorescence detector telescopes .and 1600 surface detectors. As such, it will provide a large number of events with less systematic detection uncertainties. The construction of the Observatory is quite advanced and the buildings at the Central Station in Malargüe city are already operational. So are the telescope buildings at Cerros Los Leones and Coihueco, two telescopes, 32 surface detectors, the telecommunication and data adquisión systems. From the scientific point of view the most important issue was the first detection of an hybrid event (a cosmic ray detected by both telescope and the surface detectors), on January 2002. It confirmed the equipment operates with the design parameters. Twenty hybrid events/month were detected with energies typically below 1019 eV.

  1. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  2. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  3. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  4. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  5. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  6. Transport and capture properties of Auger-generated high-energy carriers in (AlInGa)N quantum well structures

    SciTech Connect

    Nirschl, A.; Binder, M.; Schmid, M.; Karow, M. M.; Pietzonka, I.; Lugauer, H.-J.; Zeisel, R.; Sabathil, M.; Galler, B.; Bougeard, D.

    2015-07-21

    Recent photoluminescence experiments presented by M. Binder et al. [Appl. Phys. Lett. 103, 071108 (2013)] demonstrated the visualization of high-energy carriers generated by Auger recombination in (AlInGa)N multi quantum wells. Two fundamental limitations were deduced which reduce the detection efficiency of Auger processes contributing to the reduction in internal quantum efficiency: the transfer probability of these hot electrons and holes in a detection well and the asymmetry in type of Auger recombination. We investigate the transport and capture properties of these high-energy carriers regarding polarization fields, the transfer distance to the generating well, and the number of detection wells. All three factors are shown to have a noticeable impact on the detection of these hot particles. Furthermore, the investigations support the finding that electron-electron-hole exceeds electron-hole-hole Auger recombination if the densities of both carrier types are similar. Overall, the results add to the evidence that Auger processes play an important role in the reduction of efficiency in (AlInGa)N based LEDs.

  7. The Pierre Auger Observatory progress and first results

    SciTech Connect

    Mantsch, Paul M.

    2005-08-01

    The Pierre Auger Observatory was designed for a high statistics, full sky study of cosmic rays at the highest energies. Energy, direction and composition measurements are intended to illuminate the mysteries of the most energetic particles in nature. The Auger Observatory utilizes a surface array together with air fluorescence telescopes which together provide a powerful instrument for air shower reconstruction. The southern part of the Auger Observatory, now under construction in the Province of Mendoza, Argentina, is well over half finished. Active detectors have been recording events for one and a half years. Preliminary results based on this first data set are presented.

  8. InGaN/GaN multiple-quantum-well light-emitting diodes with a grading InN composition suppressing the Auger recombination

    SciTech Connect

    Zhang, Zi-Hui; Liu, Wei; Ju, Zhengang; Tan, Swee Tiam; Ji, Yun; Kyaw, Zabu; Zhang, Xueliang; Wang, Liancheng; Sun, Xiao Wei E-mail: VOLKAN@stanfordalumni.org; Demir, Hilmi Volkan E-mail: VOLKAN@stanfordalumni.org

    2014-07-21

    In conventional InGaN/GaN light-emitting diodes (LEDs), thin InGaN quantum wells are usually adopted to mitigate the quantum confined Stark effect (QCSE), caused due to strong polarization induced electric field, through spatially confining electrons and holes in small recombination volumes. However, this inevitably increases the carrier density in quantum wells, which in turn aggravates the Auger recombination, since the Auger recombination scales with the third power of the carrier density. As a result, the efficiency droop of the Auger recombination severely limits the LED performance. Here, we proposed and showed wide InGaN quantum wells with the InN composition linearly grading along the growth orientation in LED structures suppressing the Auger recombination and the QCSE simultaneously. Theoretically, the physical mechanisms behind the Auger recombination suppression are also revealed. The proposed LED structure has experimentally demonstrated significant improvement in optical output power and efficiency droop, proving to be an effective solution to this important problem of Auger recombination.

  9. Dimensionality and its effects upon the valence electronic structure of ordered metallic systems

    SciTech Connect

    Tobin, J.G.

    1983-07-01

    The system c(10x2)Ag/Cu(001) was investigated with Angle-Resolved Photoemission (ARP), Low Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES). LEED and AES provided the calibration of a quartz microbalance used to measure the amount of silver evaporated onto the copper single crystal and also established the monolayer geometrical structure at one monolayer exposure. An off-normal ARP bandmapping study performed with polarized HeI and NeI radiation demonstrated the electronically two-dimensional nature of the silver d-bands at coverages of near one monolayer. The states at the surface Brillouin Zone center were assigned upon the basis of their polarization dependences and a structural model of hexagonal symmetry. A normal emission ARP experiment was performed at the Stanford Synchrotron Radiation Laboratory (SSRL) over the photon energy range of 6 to 32 eV. Data from it documented the evolution of the valence electronic structure of the silver overlayer from a two-dimensional hexagonal valence to a three-dimensional behavior converging towards that of bulk Ag(111). A structural study was attempted using the ARP technique of Normal Emission Photoelectron Diffraction over the photon energy range of 3.4 to 3.7 keV at SSRL, the results of which are inconclusive.

  10. Surface chemical reactions during electron beam irradiation of nanocrystalline CaS:Ce{sup 3+} phosphor

    SciTech Connect

    Kumar, Vinay; Pitale, Shreyas S.; Nagpure, I. M.; Coetsee, E.; Ntwaeaborwa, O. M.; Terblans, J. J.; Swart, H. C.; Mishra, Varun

    2010-06-15

    The effects of accelerating voltage (0.5-5 keV) on the green cathodoluminescence (CL) of CaS:Ce{sup 3+} nanocrystalline powder phosphors is reported. An increase in the CL intensity was observed from the powders when the accelerating voltage was varied from 0.5 to 5 keV, which is a relevant property for a phosphor to be used in field emission displays (FEDs). The CL degradation induced by prolonged electron beam irradiation was analyzed using CL spectroscopy, x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The AES data showed the decrease in the S peak intensity and an increase in the O peak intensity during electron bombardment. The CL intensity was found to decrease to 30% of its original intensity after about 50 C/cm{sup 2}. XPS was used to study the chemical composition of the CaS:Ce{sup 3+} nanophosphor before and after degradation. The XPS data confirms that a nonluminescent CaSO{sub 4} layer has formed on the surface during the degradation process, which may partially be responsible for the CL degradation. The electron stimulated surface chemical reaction mechanism was used to explain the effects of S desorption and the formation of the nonluminescent CaSO{sub 4} layer on the surface.

  11. BOREAS AES READAC Surface Meteorological Data

    NASA Technical Reports Server (NTRS)

    Atkinson, G. Barrie; Funk, Barry; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    Canadian AES personnel collected and processed data related to surface atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from one READAC meteorology station in Hudson Bay, Saskatchewan. Parameters include day, time, type of report, sky condition, visibility, mean sea level pressure, temperature, dewpoint, wind, altimeter, opacity, minimum and maximum visibility, station pressure, minimum and maximum air temperature, a wind group, precipitation, and precipitation in the last hour. The data were collected non-continuously from 24-May-1994 to 20-Sep-1994. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

  12. BOREAS AES MARSII Surface Meteorological Data

    NASA Technical Reports Server (NTRS)

    Atkinson, G. Barrie; Funk, Barry; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    Canadian AES personnel collected several data sets related to surface and atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from six MARSII meteorology stations in the BOREAS region in Canada. Parameters include site, time, temperature, dewpoint, visibility, wind speed, wind gust, wind direction, two cloud groups, precipitation, and station pressure. Temporally, the data cover the period of May to September 1994. Geo-graphically, the stations are spread across the provinces of Saskatchewan and Manitoba. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

  13. PCI effects and the gradual formation of Rydberg series due to photoelectron recapture, in the Auger satellite lines upon Xe 4d-15/2 photoionization

    NASA Astrophysics Data System (ADS)

    Kosugi, Satoshi; Iizawa, Masatomi; Kawarai, Yu; Kuriyama, Yosuke; Kilcoyne, A. L. David; Koike, Fumihiro; Kuze, Nobuhiko; Slaughter, Daniel S.; Azuma, Yoshiro

    2015-06-01

    The Xe (N5O2,3O2,3) Auger electron spectra originating from 4d-15/2 inner-shell photoionization were measured, with photon energy tuned close to the ionization threshold. As the photon energy approaches the threshold from above the 4d-15/2 photoionization threshold, Rydberg series structures are formed within the Auger electron peak by the recapture of the photoelectron into high-lying ion orbitals. They emerge in the tail on the higher energy side of the post-collision interaction (PCI) profile of the Auger electron. Discrete Rydberg peaks replace the continuous PCI tail and gradually form a series with intensity distribution emulating the intensity profile of the continuous tail. Structures due to the Xe+5p4(1S0, 1D2, 3P2,1,0) ml series were observed and assigned.

  14. Characterization of Secondary Electron Emission Properties of Plasma Facing Materials

    NASA Astrophysics Data System (ADS)

    Patino, Marlene I.; Capece, Angela M.; Raitses, Yevgeny; Koel, Bruce E.

    2015-11-01

    The behavior of wall-bounded plasmas is significantly affected by the plasma-wall interactions, including the emission of secondary electrons (SEE) from the wall materials due to bombardment by primary electrons. The importance of SEE has prompted previous investigations of SEE properties of materials especially with applications to magnetic fusion, plasma thrusters, and high power microwave devices. In this work, we present results of measurements of SEE properties of graphite and lithium materials relevant for the divertor region of magnetic fusion devices. Measurements of total SEE yield (defined as the number of emitted secondary electrons per incident primary electron) for lithium are extended up to 5 keV primary electron energy, and the energy distributions of secondary electrons are provided for graphite and lithium. Additionally, the effect of contamination on the total SEE yield of lithium was explored by exposing the material to water vapor. Auger electron spectroscopy (AES) was used to determine surface composition and temperature programmed desorption (TPD) was used to determine lithium film thickness. Results show an order of magnitude increase in total SEE yield for lithium exposed to water vapor. This work was supported by DOE contract DE-AC02-09CH11466; AFOSR grants FA9550-14-1-0053, FA9550-11-1-0282, and AF9550-09-1-0695; and DOE Office of Science Graduate Student Research Program.

  15. The Surface Detector System of the Pierre Auger Observatory

    SciTech Connect

    Allekotte, I.; Barbosa, A.F.; Bauleo, P.; Bonifazi, C.; Civit, B.; Escobar, C.O.; Garcia, B.; Guedes, G.; Gomez Berisso, M.; Harton, J.L.; Healy, M.; /Cuyo U. /Buenos Aires, CONICET /Natl. Tech. U., San Rafael /Campinas State U. /UEFS, Feira de Santana /Bahia U. /BUAP, Puebla /Santiago de Compostela U. /Fermilab /UCLA /Colorado State U.

    2007-11-01

    The Pierre Auger Observatory is designed to study cosmic rays with energies greater than 10{sup 19} eV. Two sites are envisaged for the observatory, one in each hemisphere, for complete sky coverage. The southern site of the Auger Observatory, now approaching completion in Mendoza, Argentina, features an array of 1600 water-Cherenkov surface detector stations covering 3000 km{sup 2}, together with 24 fluorescence telescopes to record the air shower cascades produced by these particles. The two complementary detector techniques together with the large collecting area form a powerful instrument for these studies. Although construction is not yet complete, the Auger Observatory has been taking data stably since January 2004 and the first physics results are being published. In this paper we describe the design features and technical characteristics of the surface detector stations of the Pierre Auger Observatory.

  16. Auger decay of 3p-ionized krypton

    SciTech Connect

    Jonauskas, V.; Kucas, S.; Karazija, R.

    2011-11-15

    A theoretical study of Auger cascades during the decay of 3p{sub 1/2} and 3p{sub 3/2} vacancies in krypton has been performed by level-by-level calculations using a wide configuration interaction basis. Auger spectra for all steps of the cascades are presented and are compared with the existing experimental data. Good agreement of our results with the branching ratios of ions measured by a coincidence technique is obtained.

  17. The Pierre Auger Observatory: Mass composition results and future plans

    NASA Astrophysics Data System (ADS)

    Hervé, A. E.; Pierre Auger Collaboration

    2016-07-01

    The Pierre Auger Observatory has been designed to study ultra-high energy cosmic rays. The study of their mass composition can help constrain models concerning their nature and origin. We discuss the different methods of deriving the mass composition of the primary cosmic rays. The methods use different parameters that describe various characteristics of the shower development. We will also discuss the prospects expected from an upgrade of the Pierre Auger Observatory.

  18. The Cherenkov Surface Detector of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Billoir, Pierre

    2014-12-01

    The Pierre Auger Observatory detects the atmospheric showers induced by cosmic rays of ultra-high energy (UHE). It is the first one to use the hybrid technique. A set of telescopes observes the fluorescence of the nitrogen molecules on clear moonless nights, giving access to the longitudinal profile of the shower. These telescopes surround a giant array of 1600 water Cherenkov tanks (covering more than 3000 km2), which works continuously and samples the particles reaching the ground (mainly muons, photons and electrons/positrons); the light produced within the water is recorded into FADC (Fast Analog to Digital Convertes) traces. A subsample of hybrid events provides a cross calibration of the two components. We describe the structure of the Cherenkov detectors, their sensitivity to different particles and the information they can give on the direction of origin, the energy and the nature of the primary UHE object; we discuss also their discrimination power for rare events (UHE photons or neutrinos). To cope with the variability of weather conditions and the limitations of the communication system, the procedures for trigger and real time calibration have been shared between local processors and a central acquisition system. The overall system has been working almost continuously for 10 years, while being progressively completed and increased by the creation of a dense "infill" subarray.

  19. Design of a rotary stepped auger for a lunar environment

    NASA Technical Reports Server (NTRS)

    Dardet, Eduardo; Hart, Derek; Herod, Chris; Homiller, Stephen; Meeks, Mickey; Platt, Kirsten

    1988-01-01

    A lunar outpost will have need for deep drilling operations for both explorative and practical purposes. As in any drilling operation, the cuttings must be cleared from the hole. The hard vacuum of the lunar environment renders conventional flushing methods of cutting removal unfeasible, and requires a new system of removal. A rotary stepped auger (RSA) is a simple mechanical method of removing dry cuttings from a deep hole, and is ideally suited to the lunar environment. The RSA consists of a helical auger with stepped ramps which allow cuttings to slide up the helix, but will prevent them from sliding back down. The auger is driven in a pulsed manner by applying a periodic function of acceleration to the auger shaft. These pulses will compel the cuttings to slide up the auger's helix while the stepped ramps prevent the cuttings from backsliding while the auger accelerates. A mathematical model of the RSA was developed and experimentally evaluated. The math model produced a good baseline design, but the experimental model required some tuning to account for the approximations made in the math model. This design is suited for lunar drilling because it is mechanically simple, integral to the drill string, requires no fluids, is suited to the dry soil, and has relatively low weight and power requirements.

  20. Resonant Auger decay of Xe{sup *} 4d{sub 5/2}{sup -1}6p: A contribution to the complete experiment from fluorescence polarization studies

    SciTech Connect

    O'Keeffe, P.; Aloiese, S.; Meyer, M.; Lohmann, B.; Kleiman, U.; Grum-Grzhimailo, A. N.

    2004-07-01

    Fluorescence polarimetry has been used to determine the relative partial-wave Auger decay widths for transitions to states of the Xe II 5p{sup 4}6p multiplet after photoexcitation of the Xe{sup *} 4d{sub 5/2}{sup -1}6p(J{sup *}=1) resonance by linearly and circularly polarized synchrotron radiation. Combination with data on the angular distribution and spin polarization of the Auger electrons, providing information on the relative phases of the amplitudes, constitutes the complete experiment on the Auger decay. Multiconfiguration relativistic calculations of the amplitudes have been performed and compared to the measurements.

  1. AE measurements for evaluation of defects in FRP pressure vessels

    SciTech Connect

    Kawahara, Masanori; Takatsu, Takashi

    1995-11-01

    AE (acoustic emission) measurement was conducted in a series of pressuring tests of FRP pressure vessels in order to examine its applicability to the safety evaluation of vessels. Tested vessels were commercial FRP pressure vessels fabricated by filament winding of high strength glass fibers, impregnated epoxy resin, on a Al alloy liner. At the final stage of fabrication, they were subjected to autofrettage, an overpressuring treatment to produce compressive residual stresses in metal liner. AE measurement results showed a strong Kaiser`s effect and high felicity ratios. In a virgin vessel, very few AE signals were detected below the autofrettage pressure. Vessels containing artificial defects showed distinct increase in AE signals at the level of test pressure. AE origin map were obtained by triangular-zone calculation. Discussions are directed, in particular, to the selection of threshold and to the applicability of AE measurement to the in-service inspection of FRP pressure vessel.

  2. Pierre Auger Atmosphere-Monitoring Lidar System

    NASA Astrophysics Data System (ADS)

    Filipcic, A.; Horvat, M.; Veberic, D.; Zavrtanik, D.; Zavrtanik, M.; Chiosso, M.; Mussa, R.; Sequeiros, G.; Mostafa, M. A.; Roberts, M. D.

    2003-07-01

    The fluorescence-detection techniques of cosmic-ray air-shower experiments require precise knowledge of atmospheric properties to reconstruct air-shower energies. Up to now, the atmosphere in desert-like areas was assumed to be stable enough so that o ccasional calibration of atmospheric attenuation would suffice to reconstruct shower profiles. However, serious difficulties have been reported in recent fluorescence-detector experiments causing systematic errors in cosmic ray spectra at extreme energies. Therefore, a scanning backscatter lidar system has been constructed for the Pierre Auger Observatory in Malargue, Argentina, where ¨ on-line atmospheric monitoring will be performed. One lidar system is already deployed at the Los Leones fluorescence detector (FD) site and the second one is currently (April 2003) under construction at the Coihueco site. Next to the established ones, a novel analysis method with assumption on horizontal invariance, using multi-angle measurements is shown to unambiguously measure optical depth, as well as absorption and backscatter coefficient.

  3. A Complete Set of Radiative and Auger Rates for K-vacancy States in Fe XVIII-Fe-XXV

    NASA Technical Reports Server (NTRS)

    Palmeri, P.; Mendoza, C.; Kallman, T. R.; Bautista, M. A.

    2003-01-01

    A complete set of level energies, wavelengths, A-values, and total and partial Auger rates have been computed for transitions involving the K-vacancy states within the n = 2 complex of Fe XVIII-Fe XXV. Three different standard numerical packages are used for this purpose, namel y AUTOSTRUCTURE, the Breit-Pauli R-matrix suite (BPRM) and HFR, which allow reliable estimates of the physical effects involved and of the accuracy of the resulting data sets. The Breit interaction is taken i nto account because its contributions to the small A-values and partial Auger rates cannot be neglected with increasing electron occupancy. Semiempirical adjustments can also lead to large differences in both the radiative and Auger decay data of strongly mixed levels. Several experimental level energies and wavelengths are questioned, and significant discrepancies are found with previously computed decay rates th at are attributed to numerical problems. The statistical accuracy of the present level energies and wavelengths is ranked at +/-3 eV and +/ -2 mA, respectively, and that for A-values and partial Auger rates greater than lO(exp 13)/s at better than 20%.

  4. A Complete Set of Radiative and Auger Rates for K-vacancy States in Fe XVIII-Fe XXV

    NASA Technical Reports Server (NTRS)

    Palmeri, P.; Mendoza, C.; Kallman, T. R.; Bautista, M. A.

    2002-01-01

    A complete set of level energies, wavelengths, A-values, and total and partial Auger rates have been computed for transitions involving the K-vacancy states within the n = 2 complex of Fe XVIII-Fe XXV. Three different standard numerical packages are used for this purpose, namely AUTOSTRUCTURE, the Breit-Pauli R-matrix suite (BPRM) and HFR, which allow reliable estimates of the physical effects involved and of the accuracy of the resulting data sets. It is found that the Breit interaction must be always taken into account as the contributions to the small A-values and partial Auger rates does not decrease with electron occupancy. Semi-empirical adjustments can also lead to large differences in both the radiative and Auger decay data of strongly mixed levels. Several experimental energy levels and wavelengths are questioned, and significant discrepancies are found with previously computed decay rates that are attributed to numerical problems. The statistical accuracy of the present level energies and wavelengths is ranked at plus or minus 3 eV and plus or minus 2 mAngstroms, respectively, whereas that for A-values and partial Auger rates greater than 10(exp 13) per second is estimated at better than 20%.

  5. Energy efficiency analysis and implementation of AES on an FPGA

    NASA Astrophysics Data System (ADS)

    Kenney, David

    The Advanced Encryption Standard (AES) was developed by Joan Daemen and Vincent Rjimen and endorsed by the National Institute of Standards and Technology in 2001. It was designed to replace the aging Data Encryption Standard (DES) and be useful for a wide range of applications with varying throughput, area, power dissipation and energy consumption requirements. Field Programmable Gate Arrays (FPGAs) are flexible and reconfigurable integrated circuits that are useful for many different applications including the implementation of AES. Though they are highly flexible, FPGAs are often less efficient than Application Specific Integrated Circuits (ASICs); they tend to operate slower, take up more space and dissipate more power. There have been many FPGA AES implementations that focus on obtaining high throughput or low area usage, but very little research done in the area of low power or energy efficient FPGA based AES; in fact, it is rare for estimates on power dissipation to be made at all. This thesis presents a methodology to evaluate the energy efficiency of FPGA based AES designs and proposes a novel FPGA AES implementation which is highly flexible and energy efficient. The proposed methodology is implemented as part of a novel scripting tool, the AES Energy Analyzer, which is able to fully characterize the power dissipation and energy efficiency of FPGA based AES designs. Additionally, this thesis introduces a new FPGA power reduction technique called Opportunistic Combinational Operand Gating (OCOG) which is used in the proposed energy efficient implementation. The AES Energy Analyzer was able to estimate the power dissipation and energy efficiency of the proposed AES design during its most commonly performed operations. It was found that the proposed implementation consumes less energy per operation than any previous FPGA based AES implementations that included power estimations. Finally, the use of Opportunistic Combinational Operand Gating on an AES cipher

  6. Modification of the aggregation behaviour of the environmental Ralstonia eutropha-like strain AE815 is reflected by both surface hydrophobicity and amplified fragment length polymorphism (AFLP) patterns.

    PubMed

    Bossier, P; Top, E M; Huys, G; Kersters, K; Boonaert, C J; Rouxhet, P G; Verstraete, W

    2000-02-01

    After inoculation of the plasmid-free non-aggregative Ralstonia eutropha-like strain AE815 in activated sludge, followed by reisolation on a selective medium, a mutant strain A3 was obtained, which was characterized by an autoaggregative behaviour. Strain A3 had also acquired an IncP1 plasmid, pLME1, co-aggregated with yeast cells when co-cultured, and stained better with Congo red than did the AE815 strain. Contact angle measurements showed that the mutant strain was considerably more hydrophobic than the parent strain AE815, and scanning electron microscopy (SEM) revealed the production of an extracellular substance. A similar hydrophobic mutant (AE176R) could be isolated from the AE815-isogenic R. eutropha-like strain AE176. With the DNA fingerprinting technique repetitive extragenic palindromic-polymerase chain reaction (REP-PCR), no differences between these four strains, AE815, A3, AE176 and AE176R, could be revealed. However, using the amplified fragment length polymorphism (AFLP) DNA fingerprinting technique with three different primer combinations, small but clear reproducible differences between the banding patterns of the autoaggregative mutants and their non-autoaggregative parent strains were observed for each primer set. These studies demonstrate that, upon introduction of a strain in an activated sludge microbial community, minor genetic changes readily occur, which can nevertheless have major consequences for the phenotype of the strain and its aggregation behaviour. PMID:11243262

  7. BOREAS AES Campbell Scientific Surface Meteorological Data

    NASA Technical Reports Server (NTRS)

    Atkinson, G. Barrie; Funk, Barrie; Knapp. David E. (Editor); Hall, Forrest G. (Editor)

    2000-01-01

    Canadian AES personnel collected data related to surface and atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from 14 automated meteorology stations located across the BOREAS region. Included in this data are parameters of date, time, mean sea level pressure, station pressure, temperature, dew point, wind speed, resultant wind speed, resultant wind direction, peak wind, precipitation, maximum temperature in the last hour, minimum temperature in the last hour, pressure tendency, liquid precipitation in the last hour, relative humidity, precipitation from a weighing gauge, and snow depth. Temporally, the data cover the period of August 1993 to December 1996. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

  8. Multiple Lookup Table-Based AES Encryption Algorithm Implementation

    NASA Astrophysics Data System (ADS)

    Gong, Jin; Liu, Wenyi; Zhang, Huixin

    Anew AES (Advanced Encryption Standard) encryption algorithm implementation was proposed in this paper. It is based on five lookup tables, which are generated from S-box(the substitution table in AES). The obvious advantages are reducing the code-size, improving the implementation efficiency, and helping new learners to understand the AES encryption algorithm and GF(28) multiplication which are necessary to correctly implement AES[1]. This method can be applied on processors with word length 32 or above, FPGA and others. And correspondingly we can implement it by VHDL, Verilog, VB and other languages.

  9. Xenon N4,500 Auger spectrum - a useful calibration source

    SciTech Connect

    Carroll, T.X.; Bozek, J.D.; Kukk, E.; Myrseth, V.; Saethre, L.J.; Thomas, T.D.; Wiesner, Karoline

    2002-02-06

    In the xenon N4,5OO Auger spectrum there are 19 prominent lines ranging from 8 to 36 eV that provide a convenient set of standards for calibrating electron spectrometers. Combining optical data with recent measurements of this spectrum gives energies for these lines that are absolutely accurate to 11 meV. For most lines the relative accuracy is better than 1 meV; for a few it is about 3 meV. The spin-orbit splitting of the xenon 4d lines is measured to be 1979.0 +- 0.5meV.

  10. Adhesion and transfer of PTFE to metals studied by auger emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.; Buckley, D. H.

    1972-01-01

    The adhesion and transfer of polytetrafluoroethylene (PTFE) to metals in ultrahigh vacuum has been studied using Auger emission spectroscopy. The transfer was effected both by compressive static contact and by sliding contact. The transfer observed after static contact was independent of the chemical constitution of the substrate. Electron induced desorption of the fluorine in the transferred PTFE showed that the fluorine had no chemical interaction with the metal substrate. The coefficient of friction on metals was independent of the chemical constitution of the substrate. However, sliding PTFE on soft metals such as aluminum, generated wear fragments that lodged in the PTFE and machined the substrate.

  11. Auger spectroscopy analysis of lubrication with zinc dialkyldithiophosphate of several metal combinations in sliding contact

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1979-01-01

    Sliding friction experiments were conducted with aluminum and other riders rubbing on disks of various elemental metals in the presence of a thin film of zinc dialkyldithiophosphate (ZDP). Auger emission spectroscopy was used to in situ monitor the changes in surface chemistry with rubbing under various loads. The metal disks examined included iron, titanium, rhodium, tungsten, molybdenum, and copper. For equivalent films of ZDP the film is a more effective lubricant for some metals than it is for others. The important active element in the compound varies with the metal lubricated and is a function of metal chemistry. The zinc in the ZDP is susceptible to electron beam induced desorption.

  12. PDS 144: THE FIRST CONFIRMED Herbig Ae-Herbig Ae WIDE BINARY

    SciTech Connect

    Hornbeck, J. B.; Williger, G. M.; Lauroesch, J. T.; Grady, C. A.; Perrin, M. D.; Grogin, N. A.; Wisniewski, J. P.; Tofflemire, B. M.; Brown, A.; Holtzman, J. A.; Arraki, K.; Hamaguchi, K.; Woodgate, B.; Petre, R.; Bonfield, D. G.; Daly, B.

    2012-01-01

    PDS 144 is a pair of Herbig Ae stars that are separated by 5.''35 on the sky. It has previously been shown to have an A2Ve Herbig Ae star viewed at 83 Degree-Sign inclination as its northern member and an A5Ve Herbig Ae star as its southern member. Direct imagery revealed a disk occulting PDS 144 N-the first edge-on disk observed around a Herbig Ae star. The lack of an obvious disk in direct imagery suggested PDS 144 S might be viewed face-on or not physically associated with PDS 144 N. Multi-epoch Hubble Space Telescope imagery of PDS 144 with a 5 year baseline demonstrates PDS 144 N and S are comoving and have a common proper motion with TYC 6782-878-1. TYC 6782-878-1 has previously been identified as a member of Upper Sco sub-association A at d = 145 {+-} 2 pc with an age of 5-10 Myr. Ground-based imagery reveals jets and a string of Herbig-Haro knots extending 13' (possibly further) which are aligned to within 7 Degree-Sign {+-} 6 Degree-Sign on the sky. By combining proper motion data and the absence of a dark mid-plane with radial velocity data, we measure the inclination of PDS 144 S to be i = 73 Degree-Sign {+-} 7 Degree-Sign . The radial velocity of the jets from PDS 144 N and S indicates they, and therefore their disks, are misaligned by 25 Degree-Sign {+-} 9 Degree-Sign . This degree of misalignment is similar to that seen in T Tauri wide binaries.

  13. PDS 144: The First Confirmed Herbig Ae-Herbig Ae Wide Binary

    NASA Technical Reports Server (NTRS)

    Hornbeck, J. B.; Grady, C. A.; Perrin, M. D.; Wisniewski, J. P.; Tofflemire, B. M.; Brown, A.; Holtzman, J. A.; Arraki, K.; Hamaguchi, K.; Woodgate, B.; Petre, R.; Daly, B.; Grogin, N. A.; Bonfield, D. G.; Williger, G. M.; Lauroesch, J. T.

    2012-01-01

    PDS 144 is a pair of Herbig Ae stars that are separated by 5.35" on the sky. It has previously been shown to have an A2Ve Herbig Ae star viewed at 83 deg inclination as its northern member and an A5Ve Herbig Ae star as its southern member. Direct imagery revealed a disk occulting PDS 144 N - the first edge-on disk observed around a Herbig Ae star. The lack of an obvious disk in direct imagery suggested PDS 144 S might be viewed face-on or not physically associated with PDS 144 N. Multi-epoch HST imagery of PDS 144 with a 5 yr baseline demonstrates PDS 144 N & S are comoving and have a common proper motion with TYC 6782-878-1. TYC 6782-878-1 has previously been identified as a member of Upper Sco sub-association A at d = 145 +/- 2 pc with an age of 5 - 10 Myr. Ground-based imagery reveals jets and a string of HH knots extending 13' (possibly further) which are aligned to within 7 deg +/- 6 deg on the sky. By combining proper motion data and the absence of a dark mid-plane with radial velocity data, we measure the inclination of PDS 144 S to be i = 73 deg +/- 7 deg. The radial velocity of the jets from PDS 144 N & S indicates they, and therefore their disks, are misaligned by 25 deg +/- 9 deg.. This degree of misalignment is similar to that seen in T-Tauri wide binaries.

  14. Complex multireference configuration interaction calculations for the K-vacancy Auger states of Nq+ (q = 2-5) ions

    NASA Astrophysics Data System (ADS)

    Peng, Yi-Geng; Wu, Yong; Zhu, Lin-Fan; Zhang, Song Bin; Wang, Jian-Guo; Liebermann, H.-P.; Buenker, R. J.

    2016-02-01

    K-vacancy Auger states of Nq+ (q = 2-5) ions are studied by using the complex multireference single- and double-excitation configuration interaction (CMRD-CI) method. The calculated resonance parameters are in good agreement with the available experimental and theoretical data. It shows that the resonance positions and widths converge quickly with the increase of the atomic basis sets in the CMRD-CI calculations; the standard atomic basis set can be employed to describe the atomic K-vacancy Auger states well. The strong correlations between the valence and core electrons play important roles in accurately determining those resonance parameters, Rydberg electrons contribute negligibly in the calculations. Note that it is the first time that the complex scaling method has been successfully applied for the B-like nitrogen. CMRD-CI is readily extended to treat the resonance states of molecules in the near future.

  15. Education and Outreach for the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Snow, G.

    The scale and scope of the physics studied at the Auger Observatory offer significant opportunities for original outreach work. Education, outreach and public relations of the Auger collaboration are coordinated in a separate task whose goals are to encourage and support a wide range of education and outreach efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. The presentation will focus on the impact of the collaboration in Mendoza Province, Argentina, as: the Auger Visitor Center in Malargüe that has hosted over 25,000 visitors since 2001, the Auger Celebration and a collaboration-sponsored science fair held on the Observatory campus in November 2005, the opening of the James Cronin School in Malargüe in November 2006, public lectures, school visits, and courses for science teachers. As the collaboration prepares its northern hemisphere site proposal, plans for an enhanced outreach program are being developed in parallel and will be described.

  16. Hemispherical Analyser with 2-D PSD for Zero-degree Auger Projectile Spectroscopy

    NASA Astrophysics Data System (ADS)

    Benis, E. P.; Zouros, T. J. M.; Aliabadi, H.; Richard, P.

    Details of a new high gain zero-degree Auger projectile electron spectrograph using a hemispherical analyser and a 2-dimensional position sensitive detector (PSD) with multichannel plates and a resistive anode encoder are presented. A four-element lens mounted at the entrance of the analyser, provides a virtual slit for the incoming electrons by focusing them while at the same time decelerating them to improve their energy resolution. Electrons enter through an aperture at a position R0 which is displaced (along the energy dispersion axis) with respect to the commonly used central entrance position at 1/2 (R1+R2). The analyser has an acceptance energy range of 20% and an energy resolution of 0.9%. An ion-optics trajectory simulation indicates improved focusing properties for this off-center position thus avoiding the need for cumbersome fringing field correction schemes. Test measurements of high resolution projectile Auger spectra produced in 21.7 MeV collisions of F8+ and F7+ projectiles with H2 and He are presented.

  17. Auger decay of 1{sigma}{sub g} and 1{sigma}{sub u} hole states of the N{sub 2} molecule: Disentangling decay routes from coincidence measurements

    SciTech Connect

    Semenov, S. K.; Schoeffler, M. S.; Titze, J.; Petridis, N.; Jahnke, T.; Cole, K.; Schmidt, L. Ph. H.; Czasch, A.; Jagutzki, O.; Schmidt-Boecking, H.; Doerner, R.; Akoury, D.; Williams, J. B.; Landers, A. L.; Osipov, T.; Lee, S.; Prior, M. H.; Belkacem, A.; Weber, Th.; Cherepkov, N. A.

    2010-04-15

    Results of the most sophisticated measurements in coincidence with the angular-resolved K-shell photoelectrons and Auger electrons and with two atomic ions produced by dissociation of N{sub 2} molecule are analyzed. Detection of photoelectrons at certain angles makes it possible to separate the Auger decay processes of the 1{sigma}{sub g} and 1{sigma}{sub u} core-hole states. The Auger electron angular distributions for each of these hole states are measured as a function of the kinetic-energy release of two atomic ions and are compared with the corresponding theoretical angular distributions. From that comparison one can disentangle the contributions of different repulsive doubly charged molecular ion states to the Auger decay. Different kinetic-energy-release values are directly related to the different internuclear distances. In this way one can trace experimentally the behavior of the potential energy curves of dicationic final states inside the Frank-Condon region. Presentation of the Auger-electron angular distributions as a function of kinetic-energy release of two atomic ions opens a new dimension in the study of Auger decay.

  18. 15 CFR 758.2 - Automated Export System (AES).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 2 2012-01-01 2012-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics Regulations (FTSR) (15 CFR Part 30) contain provisions for filing Shipper's Export Declarations...

  19. 15 CFR 758.2 - Automated Export System (AES).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics Regulations (FTSR) (15 CFR Part 30) contain provisions for filing Shipper's Export Declarations...

  20. 15 CFR 758.2 - Automated Export System (AES).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics Regulations (FTSR) (15 CFR part 30) contain provisions for filing Shipper's Export Declarations...

  1. 15 CFR 758.2 - Automated Export System (AES).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false Automated Export System (AES). 758.2... CLEARANCE REQUIREMENTS § 758.2 Automated Export System (AES). The Census Bureau's Foreign Trade Statistics Regulations (FTSR) (15 CFR Part 30) contain provisions for filing Shipper's Export Declarations...

  2. A Grammar Sketch of the Kaki Ae Language.

    ERIC Educational Resources Information Center

    Clifton, John M.

    Kaki Ae is a non-Austronesian language spoken by about 300 people on the south coast of Papua New Guinea, at best distantly related to any other language in that area. A brief grammar sketch of the language is presented, including discussion of the phonology, sentences, phrases, words, and morpheme categories. Kaki Ae phonemics include 11…

  3. IrAE – an asparaginyl endopeptidase (legumain) in the gut of the hard tick Ixodes ricinus

    PubMed Central

    Sojka, Daniel; Hajdušek, Ondřej; Dvořák, Jan; Sajid, Mohammed; Franta, Zdeněk; Schneider, Eric L.; Craik, Charles S.; Vancová, Marie; Burešová, Veronika; Bogyo, Matthew; Sexton, Kelly B.; McKerrow, James H.; Caffrey, Conor R.; Kopáček, Petr

    2008-01-01

    Ticks are ectoparasitic blood-feeders and important vectors for pathogens including arboviruses, rickettsiae, spirochetes and protozoa. As obligate blood-feeders, one possible strategy to retard disease transmission is disruption of the parasite’s ability to digest host proteins. However, the constituent peptidases in the parasite gut and their potential interplay in the digestion of the blood meal are poorly understood. We have characterized a novel asparaginyl endopeptidase (legumain) from the hard tick Ixodes ricinus (termed IrAE), which is the first such characterization of a clan CD family C13 cysteine peptidase (protease) in arthropods. By RT-PCR of different tissues, IrAE mRNA was only expressed in the tick gut. Indirect immunofluorescence and electron microscopy localized IrAE in the digestive vesicles of gut cells and within the peritrophic matrix. IrAE was functionally expressed in Pichia pastoris and reacted with a specific peptidyl fluorogenic substrate, and acyloxymethyl ketone and aza-asparagine Michael acceptor inhibitors. IrAE activity was unstable at pH ≥ 6.0 and was shown to have a strict specificity for asparagine at P1 using a positional scanning synthetic combinatorial library. The enzyme hydrolyzed protein substrates with a pH optimum of 4.5, consistent with the pH of gut cell digestive vesicles. Thus, IrAE cleaved the major protein of the blood meal, hemoglobin, to a predominant peptide of 4 kDa. Also, IrAE trans-processed and activated the zymogen form of Schistosoma mansoni cathepsin B1 – an enzyme contributing to hemoglobin digestion in the gut of that bloodfluke. The possible functions of IrAE in the gut digestive processes of I. ricinus are compared with those suggested for other hematophagous parasites. PMID:17336985

  4. The global compendium of Aedes aegypti and Ae. albopictus occurrence

    PubMed Central

    Kraemer, Moritz U. G.; Sinka, Marianne E.; Duda, Kirsten A.; Mylne, Adrian; Shearer, Freya M.; Brady, Oliver J.; Messina, Jane P.; Barker, Christopher M.; Moore, Chester G.; Carvalho, Roberta G.; Coelho, Giovanini E.; Van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G. R. William; Elyazar, Iqbal R. F.; Teng, Hwa-Jen; Hay, Simon I.

    2015-01-01

    Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit. PMID:26175912

  5. Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface chemistry

    NASA Astrophysics Data System (ADS)

    Kanjilal, A.; Catalfano, M.; Harilal, S. S.; Hassanein, A.; Rice, B.

    2012-03-01

    Time dependent changes in 13.5 nm extreme ultraviolet (EUV) reflectivity of Ru mirrors due to variations in surface composition were investigated. The surface properties of Ru films were analyzed in situ by means of X-ray photoelectron spectroscopy (XPS), and further verified by Auger electron spectroscopy (AES). Moreover, the impact on EUV reflectivity (EUVR) with time was examined in situ via continuous and/or discrete EUV exposures. The rapid decrease in EUVR was observed in the presence of photoelectrons (PEs) from Ru mirror of the EUV setup, whereas no significant variation was recorded by screening out additional PEs. Detailed XPS and AES analyses suggest that carbon deposition via dissociation of residual hydrocarbons plays a dominant role in the presence of additional PEs, and thus reduces the reflectivity rapidly. Using EUV photoelectron spectroscopy, systematic reduction of the secondary electron yield from the Ru mirror surface was observed in consecutive scans, and therefore supports the formation of carbonaceous Ru surface in the presence of additional PEs.

  6. Auger recombination in sodium-iodide scintillators from first principles

    SciTech Connect

    McAllister, Andrew; Åberg, Daniel; Schleife, André; Kioupakis, Emmanouil

    2015-04-06

    Scintillator radiation detectors suffer from low energy resolution that has been attributed to non-linear light yield response to the energy of the incident gamma rays. Auger recombination is a key non-radiative recombination channel that scales with the third power of the excitation density and may play a role in the non-proportionality problem of scintillators. In this work, we study direct and phonon-assisted Auger recombination in NaI using first-principles calculations. Our results show that phonon-assisted Auger recombination, mediated primarily by short-range phonon scattering, dominates at room temperature. We discuss our findings in light of the much larger values obtained by numerical fits to z-scan experiments.

  7. K-MM radiative Auger effect in solid Ca, Ti and Cr targets after ionization with 0.7-1.5 MeV protons

    NASA Astrophysics Data System (ADS)

    Budnar, M.; Mühleisen, A.; Hribar, M.; Janžekovič, H.; Ravnikar, M.; Šmit, Ž.; Žitnik, M.

    1992-03-01

    Radiative Auger (RAE) X-ray spectra were measured for the first time on Ca, Cr, and Ti targets after ionization by 0.7-1.5 MeV protons. The energies of the RAE X-ray transitions were compared with the energies obtained from the Auger transitions. The RAE intensities relative to the diagram K β13 line were deduced and compared with the available data from X-ray fluorescence and electron capture ionization. The relative yields obtained for Ca, Ti, and Cr were (3.14 ± 0.47), (2.44 ± 0.37) and (2.91 ± 0.58)%, respectively.

  8. Auger and X-ray PhotoelectronSpectroscopy Study of the Density ofOxygen States in Bismuth, Aluminum, Silicon, and Uranium Oxides

    SciTech Connect

    Teterin, Yu A.; Ivanov, K.E.; Teterin, A. Yu; Lebedev, A.M.; Utkin, I.O.; Vukchevich, L.

    1998-08-03

    The correlation of relative partial electron density at the oxygen ions with the intensity of Auger O KLL lines in Bi2O3, Al2O3, SiO2 and UO2 has been determined by Auger and X-ray photoelectron spectroscopic methods. The dependence of the relative intensities of Auger O KL2-3L2-3 and O KL1L2-3-lines was characterized from the binding energy of O 1s electrons. The electron density of the outer valence levels of oxygen increases as the relative intensities of Anger OKL2-3L2-3 and O KL1L2-3-lines increase. The fine structure observed in the O KL1L2-3 Auger and the O 2s XPS spectra has been explained by the formation of inner valence molecular orbitals (IVMO) from the interaction of electrons of the O 2s and filled metal ns shells.

  9. Analysis report for 241-BY-104 auger samples

    SciTech Connect

    Beck, M.A.; Bechtold, D.B.; Hey, B.E.

    1992-10-26

    This document details the analytical sample results for two auger samples of the tip 15 cm (6 in.) of tank 241-BY-104 salt cake. The thermal response of tank 241-BY-104 auger samples is generally mild. The level of cyanide and iron, and therefore of ferrocyanide is very low. Evidence of inhomogeneity is present for tank 241-By-104 salt cake. Mass and charge balances were less than ideal. The concentrations found for the major constituents, except chromium, are in line with the expectations.

  10. The Central laser facility at the Pierre Auger Observatory

    SciTech Connect

    Arqueros, F.; Bellido, J.; Covault, C.; D'Urso, D.; Di Giulio, C.; Facal, P.; Fick, B.; Guarino, F.; Malek, M.; Matthews, J.A.J.; Matthews, J.; Meyhandan, R.; Monasor, M.; Mostafa, M.; Petrinca, P.; Roberts, M.; Sommers, P.; Travnicek, P.; Valore, L.; Verzi, V.; Wiencke, Lawrence; /Utah U.

    2005-07-01

    The Central Laser Facility is located near the middle of the Pierre Auger Observatory in Argentina. It features a UV laser and optics that direct a beam of calibrated pulsed light into the sky. Light scattered from this beam produces tracks in the Auger optical detectors which normally record nitrogen fluorescence tracks from cosmic ray air showers. The Central Laser Facility provides a ''test beam'' to investigate properties of the atmosphere and the fluorescence detectors. The laser can send light via optical fiber simultaneously to the nearest surface detector tank for hybrid timing analyses. We describe the facility and show some examples of its many uses.

  11. Noise control of an auger miner cutting head

    SciTech Connect

    Pettitt, M.R.

    1982-01-01

    The noise radiated by the cutting heads of continuous mining machines is a significant contributor to the unacceptably high noise levels often found in many coal mines. This paper describes the results of the US Bureau of Mines first concerted effort to develop methods of controlling cutting-head radiated noise. The program was directed specifically toward the development of a reduced-noise auger miner cutting head. The auger miner, equipped with standard cutting heads, exposes jacksetters, the workers nearest the cutting heads, to typical noise levels in excess of 105 dBA. Noise control techniques were developed which have general applicability to other continuous miner cutting heads.

  12. Gene flow between wheat and wild relatives: empirical evidence from Aegilops geniculata, Ae. neglecta and Ae. triuncialis

    PubMed Central

    Arrigo, Nils; Guadagnuolo, Roberto; Lappe, Sylvain; Pasche, Sophie; Parisod, Christian; Felber, François

    2011-01-01

    Gene flow between domesticated species and their wild relatives is receiving growing attention. This study addressed introgression between wheat and natural populations of its wild relatives (Aegilops species). The sampling included 472 individuals, collected from 32 Mediterranean populations of three widespread Aegilops species (Aegilops geniculata, Ae. neglecta and Ae. triuncialis) and compared wheat field borders to areas isolated from agriculture. Individuals were characterized with amplified fragment length polymorphism fingerprinting, analysed through two computational approaches (i.e. Bayesian estimations of admixture and fuzzy clustering), and sequences marking wheat-specific insertions of transposable elements. With this combined approach, we detected substantial gene flow between wheat and Aegilops species. Specifically, Ae. neglecta and Ae. triuncialis showed significantly more admixed individuals close to wheat fields than in locations isolated from agriculture. In contrast, little evidence of gene flow was found in Ae. geniculata. Our results indicated that reproductive barriers have been regularly bypassed during the long history of sympatry between wheat and Aegilops. PMID:25568015

  13. Relativity: X-ray and auger transitions of highly charged ions

    SciTech Connect

    Chen, Mau Hsiung

    1989-03-06

    Many-electron QED correction is one of the unsolved problems in relativistic atomic structure calculations for many-electron systems. The accuracy of the effective-charged screening approach frequently used in the MCDF model to estimate the many-electron QED corrections is examined. The effects of relativity and configuration interaction are simultaneously important in the treatment of highly-charged ions. These effects can sometimes change the transition rates by orders of magnitude; numerous irregularities present in Auger rates and oscillator strengths along the isoelectronic sequence due to the level crossings. The spin-orbit mixing and Breit interaction are responsible for the decay of most of the high-spin metastable autoionizing states. 29 refs., 8 figs.

  14. Prototype muon detectors for the AMIGA component of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Awal, N.; Badescu, A. M.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S. G.; Blanco, A.; Blanco, M.; Blazek, J.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Brogueira, P.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Cordier, A.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; dos Anjos, R. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; Gallo, F.; García, B.; García-Gámez, D.; Garcia-Pinto, D.; Gate, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Glass, H.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Hervé, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A. W.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Louedec, K.; Lucero, A.; Malacari, M.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Mello, V. B. B.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Moura, C. A.; Müller, G.; Muller, M. A.; Müller, S.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanabria Gomez, J. D.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanca, D.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suarez Durán, M.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Tibolla, O.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vasquez, R.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Widom, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yapici, T.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.

    2016-02-01

    AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to extend its range of detection and to directly measure the muon content of the particle showers. It consists of an infill of surface water-Cherenkov detectors accompanied by buried scintillator detectors used for muon counting. The main objectives of the AMIGA engineering array, referred to as the Unitary Cell, are to identify and resolve all engineering issues as well as to understand the muon-number counting uncertainties related to the design of the detector. The mechanical design, fabrication and deployment processes of the muon counters of the Unitary Cell are described in this document. These muon counters modules comprise sealed PVC casings containing plastic scintillation bars, wavelength-shifter optical fibers, 64 pixel photomultiplier tubes, and acquisition electronics. The modules are buried approximately 2.25 m below ground level in order to minimize contamination from electromagnetic shower particles. The mechanical setup, which allows access to the electronics for maintenance, is also described in addition to tests of the modules' response and integrity. The completed Unitary Cell has measured a number of air showers of which a first analysis of a sample event is included here.

  15. Prototype muon detectors for the AMIGA component of the Pierre Auger Observatory

    DOE PAGESBeta

    Aab, Alexander

    2016-02-17

    AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to extend its range of detection and to directly measure the muon content of the particle showers. It consists of an infill of surface water-Cherenkov detectors accompanied by buried scintillator detectors used for muon counting. The main objectives of the AMIGA engineering array, referred to as the Unitary Cell, are to identify and resolve all engineering issues as well as to understand the muon-number counting uncertainties related to the design of the detector. The mechanical design, fabrication and deployment processes of the muonmore » counters of the Unitary Cell are described in this document. These muon counters modules comprise sealed PVC casings containing plastic scintillation bars, wavelength-shifter optical fibers, 64 pixel photomultiplier tubes, and acquisition electronics. The modules are buried approximately 2.25 m below ground level in order to minimize contamination from electromagnetic shower particles. The mechanical setup, which allows access to the electronics for maintenance, is also described in addition to tests of the modules' response and integrity. As a result, the completed Unitary Cell has measured a number of air showers of which a first analysis of a sample event is included here.« less

  16. Calculations of Auger intensity versus beam position for a sample with layers perpendicular to its surface

    NASA Astrophysics Data System (ADS)

    Zommer, L.; Jablonski, A.

    2010-07-01

    Recent advances in nanotechnology are a driving force for the improvement of lateral resolution in advanced analytical techniques such as scanning electron microscopy or scanning Auger microscopy (SAM). Special samples with multilayers which are perpendicular to their surface are presently proposed for testing the lateral resolution, as discussed in recent works of Senoner et al (2004 Surf. Interface Anal. 36 1423). The relevant experiment needs a theoretical description based on recent progress in the theory. Monte Carlo simulations of electron trajectories make possible an accurate description of the considered system. We selected exemplary samples, with layers perpendicular to the surface. The layer materials are elemental solids with high, medium and low atomic numbers, i.e. Au|Cu|Au and Au|Si|Au. For these systems calculations of the Auger current versus beam position were performed. We found that, for a system with layers consisting of elements of considerably different atomic numbers, the relation can have an unexpected extreme. This observation can be important in analysis of SAM pictures.

  17. Cause of the exceptionally high AE average for 2003

    NASA Astrophysics Data System (ADS)

    Prestes, A.

    2012-04-01

    In this work we focus on the year of 2003 when the AE index was extremely high (AE=341nT, with peak intensity more than 2200nT), this value is almost 100 nT higher when compared with others years of the cycle 23. Interplanetary magnetic field (IMF) and plasma data are compared with geomagnetic AE and Dst indices to determine the causes of exceptionally high AE average value. Analyzing the solar wind parameters we found that the annual average speed value was extremely high, approximately 542 km/s (peak value ~1074 km/s). These values were due to recurrent high-speed solar streams from large coronal holes, which stretch to the solar equator, and low-latitude coronal holes, which exist for many solar rotations. AE was found to increase with increasing solar wind speed and decrease when solar wind speed decrease. The cause of the high AE activity during 2003 is the presence of the high-speed corotating streams that contain large-amplitude Alfvén waves throughout the streams, which resulted in a large number of HILDCAAs events. When plasma and field of solar wind impinge on Earth's magnetosphere, the southward field turnings associated with the wave fluctuations cause magnetic reconnection and consequential high levels of AE activity and very long recovery phases on Dst, sometimes lasting until the next stream arrives.

  18. Coherent transient grating effects and auger inhibition in InAsSb systems

    SciTech Connect

    Murdin, B.N.; Pidgeon, C.R.; Ciesla, C.M.

    1995-12-31

    Pump-probe measurements of interband recombination lifetimes have been performed with the Free Electron Laser (CLIO) at room temperature undoped bulk InSb. Significant bleaching near and below the fundamental absorption edge at 7{mu}m was seen near the excitation frequency, with recovery times in the range 0.2-5 ns which were found to be strongly dependent on the pump photon energy. The scattering is dominated by Auger processes, which have rates following quadratic or linear carrier density dependence in low excitation and highly degenerate regimes respectively. The coefficients for Auger recombination in InSb at room temperature were found to be 1.1{+-}0.5x10{sup -26} cm{sup 6}s{sup -1} and 4.0{+-}0.5x 10{sup -9} cm{sup 3}s{sup -1} in these two regimes. These experiments also reveal associated coherent transient grating effects for the first time in these systems. A parametric scattering of the pump pulse into the probe beam is observed at delay times smaller than the coherence length of the FEL which allows us to determine the third-order nonlinear susceptibility and the coherence length of the laser system. A preliminary bleaching experiment on an undoped strained layer superlattice (SLS) sample of InAs/InAs{sub 0.61} Sb{sub 0.39} is also reported. It is well known that the narrower the bandgap in HgCdTe alloys the easier energy and momentum conservation becomes. This SLS structure (band edge 11I{mu}m) shows strong inhibition of the Auger recombination process with lifetimes up to 30 times longer than even the bulk InSb sample (7{mu}m). This opens the possibility of a major leap into the IR for III-V semiconductor light-emitting and detection device applications.

  19. Automated Estimating System (AES), Version 5. 1, User's manual

    SciTech Connect

    Schwarz, R.K.; Holder, D.A.

    1992-08-01

    This document describes Version 5.1 of the Automated Estimating System (AES), a personal computer-based software package. The AES is designed to aid in the creation, updating, and reporting of project cost estimates for the Estimating and Scheduling Department of the Martin Marietta Energy Systems, Inc., Engineering Division. AES provides formatted input screens to guide the user though the estimate creation/update process and provides several standardized reports that allow cost to be sorted and summarized in many different formats and at several levels of aggregation.

  20. Evaluation of the effective solid angle of a hemispherical deflector analyser with injection lens for metastable Auger projectile states

    NASA Astrophysics Data System (ADS)

    Benis, E. P.; Doukas, S.; Zouros, T. J. M.; Indelicato, P.; Parente, F.; Martins, C.; Santos, J. P.; Marques, J. P.

    2015-12-01

    The accurate determination of the electron yield of a metastable projectile Auger state necessitates the careful evaluation of the corresponding effective solid angle, i.e. the geometrical solid angle convoluted with the decay time of the metastable state. Recently, we presented (Doukas et. al., 2015) SIMION Monte Carlo type simulations of the effective solid angle for long lived projectile Auger states (lifetime τ ∼10-9-10-5s) recorded by a hemispherical spectrograph with injection lens and position sensitive detector in the direction of the projectile ion. These results are important for the accurate evaluation of the 1 s 2 s 2 p4P/2 P ratio of K-Auger cross sections whose observed non-statistical production by electron capture into He-like ions, recently a field of interesting interpretations, awaits final resolution. Here we expand and systematize our investigation using the same techniques to expose universal behaviors of the effective solid angle covering life times of 1 s 2 s 2 p4P states for all first row ions. Our results are also compared to purely geometrical calculations of the solid angle that omit the lensing effects and serve as a benchmark for a deeper insight into the effect.

  1. Enhancement of double auger decay probability in xenon clusters irradiated with a soft-x-ray laser pulse.

    PubMed

    Namba, S; Hasegawa, N; Nishikino, M; Kawachi, T; Kishimoto, M; Sukegawa, K; Tanaka, M; Ochi, Y; Takiyama, K; Nagashima, K

    2007-07-27

    The interaction of large Xe clusters with a soft x-ray laser pulse having a wavelength of 13.9 nm and an intensity of up to 2x10(10) W/cm2 was investigated using a time-of-flight ion mass spectrometer. The corresponding laser photon energy was sufficiently high to photoionize Xe 4d innershell electrons. It was found that Xe3+ ions (which result from double Auger decay of 4d vacancies) became the dominant final ionic product with increasing cluster size and x-ray intensity. This is in contrast to the results of synchrotron radiation experiments involving free Xe atoms, in which Xe2+ is the dominant resultant ion species. Possible mechanisms responsible for the enhancement of the double Auger transition probability in x-ray laser and cluster interaction are discussed. PMID:17678361

  2. The Pierre Auger Observatory: Present Status and Future Prospects

    SciTech Connect

    Petrera, Sergio

    2005-10-12

    The Pierre Auger Observatory is in advanced stage of construction in the southern site of Malargue, Argentina. This progress report mainly focuses on hybrid events, a remarkable subset of cosmic ray events which are simultaneously detected by both Surface Detector and Fluorescence Detector subsystems. The hybrid method and its performances are presented.

  3. Lining material tests for the AUGER PROJECT surface detector

    NASA Astrophysics Data System (ADS)

    Escobar, C. O.; Fauth, A. C.; Guzzo, M. M.; Shibuya, E. H.

    1999-03-01

    We are trying to obtain a suitable material to compose the lining of a water Cerenkov tank for the surface detector. part of a hybrid detector of the Auger Project. Results of tests were compared with DuPont 1073Tyvek TM and obtained a reasonable performance for (PVC+BaSO 4) material.

  4. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... environment. (5) Spoil placed on the outslope during previous mining operations shall not be disturbed if such... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF...

  5. 30 CFR 77.1502 - Auger holes; restriction against entering.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....1502 Section 77.1502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF... permitted to enter an auger hole except with the approval of the MSHA Coal Mine Safety and Health...

  6. 30 CFR 77.1502 - Auger holes; restriction against entering.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....1502 Section 77.1502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF... permitted to enter an auger hole except with the approval of the MSHA Coal Mine Safety and Health...

  7. 30 CFR 77.1502 - Auger holes; restriction against entering.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....1502 Section 77.1502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF... permitted to enter an auger hole except with the approval of the MSHA Coal Mine Safety and Health...

  8. 30 CFR 77.1502 - Auger holes; restriction against entering.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....1502 Section 77.1502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF... permitted to enter an auger hole except with the approval of the MSHA Coal Mine Safety and Health...

  9. 30 CFR 77.1502 - Auger holes; restriction against entering.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....1502 Section 77.1502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF... permitted to enter an auger hole except with the approval of the MSHA Coal Mine Safety and Health...

  10. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... safety factor for the stability of the backfill of at least 1.3. (2) All spoil generated by the auger... nonacid-, nontoxic-forming material and the backfill graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability. (4) Any...

  11. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... safety factor for the stability of the backfill of at least 1.3. (2) All spoil generated by the auger... nonacid-, nontoxic-forming material and the backfill graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability. (4) Any...

  12. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... safety factor for the stability of the backfill of at least 1.3. (2) All spoil generated by the auger... nonacid-, nontoxic-forming material and the backfill graded to a slope which is compatible with the approved postmining land use and which provides adequate drainage and long-term stability. (4) Any...

  13. 19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... filing of outbound vessel manifest information electronically (see, 15 CFR part 30). All sea carriers are... outbound vessel manifest information via the AES. 4.76 Section 4.76 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY VESSELS IN FOREIGN AND...

  14. 19 CFR 4.76 - Procedures and responsibilities of carriers filing outbound vessel manifest information via the AES.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... filing of outbound vessel manifest information electronically (see, 15 CFR part 30). All sea carriers are... for AES are found at 15 CFR 30.60. A sea carrier certified to use the module that adheres to the procedures set forth in this section and the Census Regulations (15 CFR part 30) concerning the...

  15. Influence of passive potential on the electronic property of the passive film formed on Ti in 0.1 M HCl solution during ultrasonic cavitation.

    PubMed

    Li, D G; Wang, J D; Chen, D R; Liang, P

    2016-03-01

    The influence of the applied passive potential on the electronic property of the passive film formed on Ti at different potentials in 0.1M HCl solution during ultrasonic cavitation, was investigated by electrochemical impedance spectra (EIS) and Mott-Schottky plot. The influence of the applied passive potential on the structure and composition of the passive film was studied by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The results showed that the applied passive potential can obviously affect the electronic property of the passive film formed on Ti during ultrasonic cavitation. The resistance of the passive film increased, and the donor density of the passive film decreased with increasing the potential. The flat band potential moved to positive direction and the band gap of the passive film moved to negative direction with increasing potential. AES and XPS results indicated that the thickness of the passive film increased evidently with applying passive potential. The passive film was mainly composed of the mixture of TiO and TiO2. While the TiO2 content increased with increasing the applied passive potential, and the crystallization of the passive film increased with the increased potential. PMID:26584983

  16. 15 CFR Appendix B to Part 30 - AES Filing Codes

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false AES Filing Codes B Appendix B to Part 30 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade BUREAU OF THE CENSUS, DEPARTMENT OF COMMERCE FOREIGN TRADE REGULATIONS Pt. 30, App. B Appendix B to Part 30—AES Filing Codes Part I—Method of Transportation...

  17. Upflow bioreactor having a septum and an auger and drive assembly

    DOEpatents

    Hansen, Carl S.; Hansen, Conly L.

    2007-11-06

    An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes an auger positioned in the aperture of the septum. The vessel includes an opening in the top for receiving the auger. The auger extends from a drive housing, which is position over the opening and provides a seal around the opening. The drive housing is adjustable relative to the vessel. The position of the auger in the aperture can be adjusted by adjusting the drive housing relative to the vessel. The auger adjustment mechanism allows the auger to be accurately positioned within the aperture. The drive housing can also include a fluid to provide an additional seal around the shaft of the auger.

  18. Studies of Cosmic Ray Composition and Air Shower Structure with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the average depth of shower maximum and its fluctuations with the Pierre Auger Observatory; (2) Study of the nuclear mass composition of UHECR with the surface detectors of the Pierre Auger Observatory; (3) Comparison of data from the Pierre Auger Observatory with predictions from air shower simulations: testing models of hadronic interactions; (4) A Monte Carlo exploration of methods to determine the UHECR composition with the Pierre Auger Observatory; (5) The delay of the start-time measured with the Pierre Auger Observatory for inclined showers and a comparison of its variance with models; (6) UHE neutrino signatures in the surface detector of the Pierre Auger Observatory; and (7) The electromagnetic component of inclined air showers at the Pierre Auger Observatory.

  19. Final-state screening dynamics in resonant Auger decay at the 2p edge of vanadium

    NASA Astrophysics Data System (ADS)

    Ilakovac, V.; Kralj, M.; Pervan, P.; Richter, M. C.; Goldoni, A.; Larciprete, R.; Petaccia, L.; Hricovini, K.

    2005-02-01

    We investigated the resonant Auger process near the V 2p3/2 edge in vanadium metal. Attention is centered on the onset of Auger decays and their behavior below the 2p3/2 resonance. The 2p3/23d3d decay has a crossover from the Raman-Auger to the normal Auger regime at the 2p ionization threshold. Meanwhile, Auger decays with core holes in the final state have normal Auger behavior even below the ionization threshold, the 2p3/23p3p process being visible at 2.2 eV lower photon energy. The different resonant behavior of these Auger decays can be understood within the one-step model as final-state screening effects affecting the photoexcitation.

  20. Double Core-Hole Production in N{sub 2}: Beating the Auger Clock

    SciTech Connect

    Fang, L.; Berrah, N.; Hoener, M.; Gessner, O.; Kornilov, O.; Tarantelli, F.; Pratt, S. T.; Kanter, E. P.; Buth, C.; Guehr, M.; Bucksbaum, P. H.; Cryan, J.; Glownia, M.; Bostedt, C.; Bozek, J. D.; Coffee, R.; Chen, M.; Kukk, E.; Leone, S. R.

    2010-08-20

    We investigate the creation of double K-shell holes in N{sub 2} molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.

  1. Double core hole production in N{sub 2} : beating the auger clock.

    SciTech Connect

    Fang, L.; Hoener, M.; Gessner, O.; Tarantelli, F.; Pratt, S. T.; Kornilov, O.; Buth, C.; Guhr, M.; Kanter, E. P.; Bostedt, C.; Bozek, J. D.; Bucksbaum, P. H.; Chen, M.; Coffee, R.; Cryan, J.; Glownia, J. M.; Kukk, E.; Leone, S. R.; Berrah, N.

    2010-01-01

    We investigate the creation of double K-shell holes in N{sub 2} molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.

  2. High-Energy Cosmic Ray Event Data from the Pierre Auger Cosmic Ray Observatory

    DOE Data Explorer

    The Pierre Auger Cosmic Ray Observatory in Mendoza, Argentina is the result of an international collaboration funded by 15 countries and many different organizations. Its mission is to capture high-energy cosmic ray events or air showers for research into their origin and nature. The Pierre Auger Collaboration agreed to make 1% of its data available to the public. The Public Event Explorer is a search tool that allows users to browse or search for and display figures and data plots of events collected since 2004. The repository is updated daily, and, as of June, 2014, makes more than 35,000 events publicly available. The energy of a cosmic ray is measured in Exa electron volts or EeV. These event displays can be browsed in order of their energy level from 0.1 to 41.1 EeV. Each event has an individual identification number.

    The event displays provide station data, cosmic ray incoming direction, various energy measurements, plots, vector-based images, and an ASCII data file.

  3. Multielectron coincidence study of the double Auger decay of 3d-ionized krypton

    SciTech Connect

    Andersson, E.; Hedin, L.; Rubensson, J.-E.; Karlsson, L.; Feifel, R.; Fritzsche, S.; Linusson, P.; Eland, J. H. D.

    2010-10-15

    Multielectron coincidence data for triple ionization of krypton have been recorded above the 3d ionization threshold at two photon energies (140 and 150 eV). Three principal transition pathways have been observed, two involving double Auger transitions from Kr{sup +}, and one involving single Auger transitions from Kr{sup 2+} created by direct single-photon double ionization. The decay of the 3d{sup 9} {sup 2}D{sub 5/2,3/2} states in Kr{sup +} has been analyzed in some detail and is found to be strongly dominated by cascade processes where two electrons with well-defined energies are emitted. The decay paths leading to the 4s{sup 2}4p{sup 3} {sup 4}S, {sup 2}D, and {sup 2}P states of Kr{sup 3+} are analyzed and energies of seven intermediate states in Kr{sup 2+} are given. A preliminary investigation of the decay paths from Kr{sup +} 3d{sup 9}4p{sup 5}nl shake-up states has also been carried out.

  4. Energy transfer mechanism and Auger effect in Er{sup 3+} coupled silicon nanoparticle samples

    SciTech Connect

    Pitanti, A.; Navarro-Urrios, D.; Garrido, B.; Prtljaga, N.; Daldosso, N.; Pavesi, L.; Gourbilleau, F.; Rizk, R.

    2010-09-15

    We report a spectroscopic study about the energy transfer mechanism among silicon nanoparticles (Si-np), both amorphous and crystalline, and Er ions in a silicon dioxide matrix. From infrared spectroscopic analysis, we have determined that the physics of the transfer mechanism does not depend on the Si-np nature, finding a fast (<200 ns) energy transfer in both cases, while the amorphous nanoclusters reveal a larger transfer efficiency than the nanocrystals. Moreover, the detailed spectroscopic results in the visible range here reported are essential to understand the physics behind the sensitization effect, whose knowledge assumes a crucial role to enhance the transfer rate and possibly employing the material in optical amplifier devices. Joining the experimental data, performed with pulsed and continuous-wave excitation, we develop a model in which the internal intraband recombination within Si-np is competitive with the transfer process via an Auger electron-''recycling'' effect. Posing a different light on some detrimental mechanism such as Auger processes, our findings clearly recast the role of Si-np in the sensitization scheme, where they are able to excite very efficiently ions in close proximity to their surface.

  5. Efficient pathway to neutralization of multiply charged ions produced in Auger processes.

    PubMed

    Stumpf, V; Kolorenč, P; Gokhberg, K; Cederbaum, L S

    2013-06-21

    After core ionization of an atom or molecule by an x-ray photon, multiply charged ions are produced in the Auger decay process. These ions tend to neutralize their charge when embedded in an environment. We demonstrate that, depending on the atom or molecule and its neighbors, electron transfer mediated decay (ETMD) provides a particularly efficient neutralization pathway for the majority of the ions produced by Auger decay. The mechanism is rather general. As a showcase example, we conducted an ab initio study of the NeKr2 cluster after core ionization of the Ne atom. This example has been chosen because it is amenable to both ab initio calculations and coincidence experiments. We find that even for frozen nuclei, the neutralization rate can be as fast as 0.130  ps(-1). We also show that nuclear dynamics may increase the rate by about an order of magnitude. The generality of the mechanism makes this neutralization pathway important in weakly bonded environments. PMID:23829763

  6. Measurement of the Auger parameter and Wagner plot for uranium compounds

    SciTech Connect

    Holliday, Kiel S.; Siekhaus, Wigbert; Nelson, Art J.

    2013-05-15

    In this study, the photoemission from the U 4f{sub 7/2} and 4d{sub 5/2} states and the U N{sub 6}O{sub 45}O{sub 45} and N{sub 67}O{sub 45}V x-ray excited Auger transitions were measured for a range of uranium compounds. The data are presented in Wagner plots and the Auger parameter is calculated to determine the utility of this technique in the analysis of uranium materials. It was demonstrated that the equal core-level shift assumption holds for uranium. It was therefore possible to quantify the relative relaxation energies, and uranium was found to have localized core-hole shielding. The position of compounds within the Wagner plot made it possible to infer information on bonding character and local electron density. The relative ionicity of the uranium compounds studied follows the trend UF{sub 4} > UO{sub 3} > U{sub 3}O{sub 8} > U{sub 4}O{sub 9}/U{sub 3}O{sub 7} Almost-Equal-To UO{sub 2} > URu{sub 2}Si{sub 2}.

  7. Auger recombination and free-carrier absorption in nitrides from first principles

    NASA Astrophysics Data System (ADS)

    Kioupakis, Emmanouil

    2010-03-01

    Solid-state optoelectronic devices in the blue/green part of the visible spectrum, based on group-III-nitride materials and their alloys, have a wide array of applications as well as the potential to replace incandescent and fluorescent light bulbs for general illumination. Progress in nitride light emitters research, however, is hampered by the efficiency droop effect, a severe drop in quantum efficiency at high drive currents that particularly affects devices emitting at longer wavelengths. The efficiency droop has been the subject of extensive research and several mechanisms have been proposed as its origin. One such mechanism is the Auger recombination process, a non-radiative recombination mechanism induced by free carrier scattering via the Coulomb interaction. An additional loss mechanism that affects laser devices in particular is the reabsorption of the generated light by free carriers in the device. We used first-principles calculations to study the direct as well as the indirect Auger recombination and free-carrier absorption processes, mediated by electron-phonon and alloy scattering, and identify their importance in nitride light emitters. Since the various loss processes are hard to decouple experimentally, first-principles calculations are an indispensable tool to investigate the various loss mechanisms in isolation and determine their significance.

  8. Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae=Ca,Sr,Ba, as thermoelectric materials

    SciTech Connect

    Parker, David S; Singh, David J

    2013-01-01

    We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2 Sn, Sr2 Sn and Ba2 Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli - roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature.

  9. Direct and indirect methods for studying the energetics and dynamics of the Auger Doppler effect in femtosecond ultra-fast dissociation

    NASA Astrophysics Data System (ADS)

    Björneholm, O.

    2001-09-01

    Molecules may fragment within a few femtoseconds after core-excitation, a phenomenon known as ultra-fast dissociation. With the aim of providing an understanding of the fundamental phenomenology of the Auger Doppler effect, two methods are presented to study the energetics and dynamics, i.e., the kinetic energy release and the fragment velocities in such processes. The first, direct, method is based on the shifts in kinetic energy of the Auger electrons due to the velocity acquired by the fragment in the ultra-fast dissociation process, i.e., the Auger Doppler effect. The second, indirect, method is based on total-energy arguments in a Born-Haber cycle for excitation, dissociation, and ionization. A combination of the two methods is shown to be able to reproduce experimental spectra well. Based on this, predictions are made for other, yet unstudied, molecular systems. It is also shown that the Auger Doppler effect is not static, but will exhibit dynamic photon energy dependence. The complete energetics of the three-body dissociation of a molecule into an electron, an ion, and a neutral fragment on a time-scale of a few femtoseconds can thus be accounted for.

  10. Competition between auger recombination and hot-carrier trapping in PL intensity fluctuations of type II nanocrystals.

    PubMed

    Mangum, Benjamin D; Wang, Feng; Dennis, Allison M; Gao, Yongqian; Ma, Xuedan; Hollingsworth, Jennifer A; Htoon, Han

    2014-07-23

    Performing time-tagged, time-correlated, single-photon-counting studies on individual colloidal nanocrystal quantum dots (NQDs), the evolution of photoluminescence (PL) intensity-fluctuation behaviors in near-infrared (NIR) emitting type II, InP/CdS core-shell NQDs is investigated as a function of shell thickness. It is observed that Auger recombination and hot-carrier trapping compete in defining the PL intensity-fluctuation behavior for NQDs with thin shells, whereas the role of hot-carrier trapping dominates for NQDs with thick shells. These studies further reveal the distinct ramifications of altering either the excitation fluence or repetition rate. Specifically, an increase in laser pump fluence results in the creation of additional hot-carrier traps. Alternately, higher repetition rates cause a saturation in hot-carrier traps, thus activating Auger-related PL fluctuations. Furthermore, it is shown that Auger recombination of negatively charged excitons is suppressed more strongly than that of positively charged excitons because of the asymmetry in the electron-hole confinement in type II NQDs. Thus, this study provides new understanding of how both NQD structure (shell thickness and carrier-separation characteristics) and excitation conditions can be used to tune the PL stability, with important implications for room-temperature single-photon generation. Specifically, the first non-blinking NQD capable of single-photon emission in the near-infrared spectral regime is described. PMID:24715631

  11. Primary excitation spectra in XPS and AES of Cu, CuO: Relative importance of surface and core hole effects

    NASA Astrophysics Data System (ADS)

    Pauly, N.; Tougaard, S.

    2015-11-01

    Quantitative interpretation of structures observed in XPS and AES requires models to correct for various physical processes involved. Besides the initial excitation process in XPS and AES, the measured spectrum is affected by three additional effects: the corehole(s), transport to the surface region and passage through the surface and vacuum regions. These three effects can be calculated by the QUEELS-XPS software (Quantitative analysis of Electron Energy Losses at Surfaces) in terms of energy-differential inelastic electron scattering cross sections. From this and the QUASES software (Quantitative Analysis of Surfaces by Electron Spectroscopy), background contributions and primary excitation spectra are obtained for various transitions (Cu 2p from Cu or CuO and Cu L3M23M23) and we investigate the separate effect of bulk, surface, and core hole(s) excitations. We show that the shape of the XPS and AES primary spectra and background contributions are modified slightly by surface effects and very strongly by core hole(s) effects. For metals, the intrinsic excitations give rise to a prominent spike in the background close to the XPS-peak energy. This spike will be much reduced for wide band gap insulators. Moreover our method gives an easy procedure to obtain the true primary excitation spectra for XPS and AES.

  12. Resistive Plate Chambers for the Pierre Auger array upgrade

    NASA Astrophysics Data System (ADS)

    Lopes, L.; Assis, P.; Blanco, A.; Cerda, M. A.; Carolino, N.; Cunha, O.; Ferreira, M.; Fonte, P.; Mendes, L.; Palka, M.; Pereira, A.; Pimenta, M.; Tomé, B.

    2014-10-01

    In the framework of the Pierre Auger Observatory upgrade, Resistive Plate Chambers (RPCs) have been proposed as a dedicated detector to better estimate the muonic component of Extensive Air Showers (EAS), further constraining the nature of the cosmic rays and hadronic interactions that take place in Extensive Air Showers development. RPCs are a very interesting option to fulfill the requirements: to cover large areas at low cost; particle counting from one to thousands of particles; few ns time resolution and outdoor standalone operation with very low maintenance. The present work refers to the latest advances and outcomes in order to ensure the capability of RPCs to fulfill the totality of the Auger upgrade requirements.

  13. Relativistic Radiative and Auger Rates for Fe XXIV

    NASA Technical Reports Server (NTRS)

    Bautista, M. A.; Mendoza, C.; Kallman, T. R.; Palmeri, P.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    As part of a project to compute improved atomic data for the spectral modeling of iron K lines, we report extensive calculations and comparisons of radiative and Auger rates for transitions involving the K-vacancy states in Fe XXIV. By making use of several computational codes, a detailed study is carried out of orbital representation, configuration interaction, relativistic corrections, cancellation effects, and fine tuning. It is shown that a formal treatment of the Breit interaction is essential to render the important magnetic correlations that take part in the decay pathways of this ion. As a result, the accuracy of the present A-values is firmly ranked at better than 10% while that of the Auger rates at only 15%.

  14. Nitridation of silicon /111/ - Auger and LEED results

    NASA Technical Reports Server (NTRS)

    Delord, J. F.; Schrott, A. G.; Fain, S. C., Jr.

    1980-01-01

    Clean silicon (111) (7x7) surfaces at up to 1050 C have been reacted with nitrogen ions and neutrals produced by a low energy ion gun. The LEED patterns observed are similar to those previously reported for reaction of silicon (111) (7x7) with NH3. The nitrogen KLL peak exhibits no shift or change in shape with nitride growth. At the same time the magnitude of the elemental silicon LVV peak at 92 eV decreases progressively as a new peak at 84 eV increases. The position of both peaks appears to be independent of the degree of nitridation. Since the Auger spectra are free of oxygen and other impurities, these features can be attributed only to silicon, nitrogen, and their reaction products. Characteristic features of the Auger spectra are related to LEED observations and to the growth of microcrystals of Si3N4.

  15. Fluorescence and hybrid detection aperture of the Pierre Auger Observatory

    SciTech Connect

    Bellido, J.A.; D'Urso, D.; Geenen, H.; Guarino, F.; Perrone, L.; Petrera, Sergio; Prado, L., Jr.; Salamida, F.

    2005-07-01

    The aperture of the Fluorescence Detector (FD) of the Pierre Auger Observatory is evaluated from simulated events using different detector configurations: mono, stereo, 3-FD and 4-FD. The trigger efficiency has been modeled using shower profiles with ground impacts in the field of view of a single telescope and studying the trigger response (at the different levels) by that telescope and by its neighbors. In addition, analysis cuts imposed by event reconstruction have been applied. The hybrid aperture is then derived for the Auger final extension. Taking into account the actual Surface Detector (SD) array configuration and its trigger response, the aperture is also calculated for a typical configuration of the present phase.

  16. A scaling relationship between AE and natural earthquakes

    NASA Astrophysics Data System (ADS)

    Yoshimitsu, N.; Kawakata, H.; Takahashi, N.

    2013-12-01

    Micro fracture which occurs during rock fracture experiments are called acoustic emission (AE), and it help us to understand detailed processes of fault growth. However, it was unclear whether AE can be considered as a small earthquake or not. Usually, the seismic moment and the corner frequency are used for characterizing source property. It has been reported that the seismic moment is inversely proportional to the cube of corner frequency for natural earthquakes (with magnitude higher than ~ -4). In this study, we examine continuity of this relationship toward smaller magnitude of AE (around magnitude -8), estimating the source parameters of AE. Previously, it was impossible to record AE waveforms by broadband transducers under tri-axial conditions due to lack of pressure seal mechanism. Here we achieved protection of broadband transducers to use them under high pressure environments. This achievement enabled us to do spectral analysis of AE. At the same time, we also achieved multi-channel continuous recording with a high sampling rate, so as not to miss some events smaller than threshold or hide some events behind the mask times by triggered recording. We prepared a cylindrical Westerly granite sample, 50 mm in diameter and 100 mm in height. Sealed nine broadband transducers (sensitive range; 100 kHz - 2000 kHz) were attached on the sample surface. High sampling recording as 20 MS/s per channel was continued, during tri-axial loading (confining pressure: 10 MPa) which was continued to be controlled even after the peak strength. More than 6000 hypocenters were estimated from all pick data during the experiment. We clustered events around the peak strength, so that their differences of hypocenter locations were shorter than 2 mm and their cross correlation values for more than four channels were higher than 0.8. Then, we analyzed two of the largest clusters. After calibrating transducer response, we obtained displacement spectra for S waves, and estimated their

  17. Acoustic emissions (AE) during failure of granular media

    NASA Astrophysics Data System (ADS)

    Michlmayr, Gernot; Or, Dani

    2014-05-01

    The release of shallow landslides and other geological mass movements is the result of progressive failure accumulation. Mechanical failure in disordered geologic materials occurs in intermittent breakage episodes marking the disintegration or rearrangement of load-bearing elements. Abrupt strain energy release in such breakage episodes is associated with generation of elastic waves measurable as high-frequency (kHz range) acoustic emissions (AE). The close association of AE with progressive failure events hold a promise for using such noninvasive methods to assess the mechanical state of granular Earth materials or for the development early warning methods for shallow landslides. We present numerical simulations that incorporate damage accumulation and associated stress redistribution using a fiber-bundle model. The stress released from element failure (fibers) is redistributed to the surrounding elements and eventually triggers larger failure avalanches. AE signals generated from such events and eventually hitting a virtual sensor are modeled using visco-elastic wave propagation laws. The model captures the characteristic saw-tooth shape of the observed stress-strain curves obtained from strain-controlled experiments with glass beads, including large intermittent stress release events that stem from cascading failure avalanches. The model also reproduces characteristics of AE signatures and yield a good agreement between simulation results and experimental data. Linking mechanical and AE information in the proposed modeling framework offer a solid basis for interpretation of measured field data.

  18. Muons in Air Showers at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Unger, M.

    We present measurements of muons in air showers at ultra-high energies with the Pierre Auger Observatory. The number of muons at the ground in air showers detected at large zenith angles is determined as a function of energy and the results are compared to air shower simulations. Furthermore, using data collected at zenith angles smaller than 60°, rescaling factors are derived that quantify the deficit of muon production in air shower simulations.

  19. Shell oil's auger TLP/ROV: Challenging, innovative

    SciTech Connect

    Michel, D. )

    1994-04-01

    Shell Oil Co. (Houston) is taking a bold step into the deep-water frontier with development of the $1.2 billion [open quotes]Auger[close quotes] project. After almost four years of construction. Shell Offshore has installed the Auger tension leg platform (TLP) on Garden Banks Block 426, located in the Gulf of Mexico 214 miles southwest of New Orleans in 2,860 feet of water-a depth that surpasses the previous Gulf record by more than 1,000 feet. The Auger TLP, designed and engineered by Shell, is a floating structure held in place by vertical tendons that eliminate significant vertical movement while allowing limited horizontal movement. The TLP will be the first in the Gulf of Mexico to support both a drilling rig and complete production facilities, reaching a peak projected daily production of 46,000 barrels of oil and 125 million cubic feet of gas in the year 2001. Underwater support for this deep-water project will be accomplished by use of one of the most advanced remotely operated vehicle systems ever deployed. In addition to the routine drilling tasks that present a navigation challenge for the system, the ROV is the primary and backup system for production riser connector (PRC) installation and removal operations. This task, coupled with the environmental conditions, significantly increases the total horsepower requirements of the ROV and the complexicity of the deployment system design.

  20. Investigation of the adsorption properties of borazine and characterisation of boron nitride on Rh(1 1 1) by electron spectroscopic methods

    NASA Astrophysics Data System (ADS)

    Farkas, A. P.; Török, P.; Solymosi, F.; Kiss, J.; Kónya, Z.

    2015-11-01

    The adsorption and dissociation of borazine were investigated on Rh(1 1 1) single crystal surface by Auger electron spectroscopy (AES), high resolution electron energy loss spectroscopy (HREELS) and temperature programmed desorption (TPD) methods. Borazine is one of the most frequently applied precursor molecules in the preparation process of boron nitride overlayer on metal single crystal surfaces. On Rh(1 1 1) surface it adsorbs molecularly at 140 K. We did not find any preferred orientation, although there is evidence of "flat" and perpendicular molecular geometry, too. Dehydrogenation starts even below 200 K and finishes until ∼7-800 K. No other boron or nitrogen containing products were observed in TPD beyond molecular borazine. Through the hydrogen loss of molecules hexagonal boron nitride layer forms in the 600-1100 K temperature range as it was indicated by AES and the characteristic optical phonon HREEL losses of h-BN overlayer. The adsorption behaviour of the boron nitride covered surface was also studied through the adsorption of methanol at 140 K. HREELS and TPD measurements showed that methanol adsorbed molecularly and a fraction of it dissociated to form surface methoxy and gas phase hydrogen on the h-BN/Rh(1 1 1) surface.

  1. Auger spectrum of a water molecule after single and double core ionization

    SciTech Connect

    Inhester, L.; Burmeister, C. F.; Groenhof, G.; Grubmueller, H.

    2012-04-14

    The high intensity of free electron lasers opens up the possibility to perform single-shot molecule scattering experiments. However, even for small molecules, radiation damage induced by absorption of high intense x-ray radiation is not yet fully understood. One of the striking effects which occurs under intense x-ray illumination is the creation of double core ionized molecules in considerable quantity. To provide insight into this process, we have studied the dynamics of water molecules in single and double core ionized states by means of electronic transition rate calculations and ab initio molecular dynamics (MD) simulations. From the MD trajectories, photoionization and Auger transition rates were computed based on electronic continuum wavefunctions obtained by explicit integration of the coupled radial Schroedinger equations. These rates served to solve the master equations for the populations of the relevant electronic states. To account for the nuclear dynamics during the core hole lifetime, the calculated electron emission spectra for different molecular geometries were incoherently accumulated according to the obtained time-dependent populations, thus neglecting possible interference effects between different decay pathways. We find that, in contrast to the single core ionized water molecule, the nuclear dynamics for the double core ionized water molecule during the core hole lifetime leaves a clear fingerprint in the resulting electron emission spectra. The lifetime of the double core ionized water was found to be significantly shorter than half of the single core hole lifetime.

  2. Determination of AES Orbit Elements Using Mixed Data

    NASA Astrophysics Data System (ADS)

    Kolesnik, S. Ja.; Strakhova, S. L.

    An algorithm is worked out and a program is compiled for a determination of AES (artificial Earth satellite) orbit elements using both goniometrical and range-finder observations of different precision. The observations of one or several passages carried out from one or several stations can be used. A number of observational stations and a number of observations are not limited in principle. When solving this task the AES ephemerides on the moments of observations are calculated for different sets of orbit elements. A parameter F is considered which is a function of orbit elements. The parameter presents a square-mean deviation of AES ephemeris position on the moments {J;} from its observed one. The determination of real orbit elements comes to minimizing of parameter F by orbit elements using a method of deformed polyhedron. When calculating the ephemeris the amendments for 2-d, 3-d, 4-th geopotential zone harmonics are considered.

  3. An Improved Recovery Algorithm for Decayed AES Key Schedule Images

    NASA Astrophysics Data System (ADS)

    Tsow, Alex

    A practical algorithm that recovers AES key schedules from decayed memory images is presented. Halderman et al. [1] established this recovery capability, dubbed the cold-boot attack, as a serious vulnerability for several widespread software-based encryption packages. Our algorithm recovers AES-128 key schedules tens of millions of times faster than the original proof-of-concept release. In practice, it enables reliable recovery of key schedules at 70% decay, well over twice the decay capacity of previous methods. The algorithm is generalized to AES-256 and is empirically shown to recover 256-bit key schedules that have suffered 65% decay. When solutions are unique, the algorithm efficiently validates this property and outputs the solution for memory images decayed up to 60%.

  4. A high performance hardware implementation image encryption with AES algorithm

    NASA Astrophysics Data System (ADS)

    Farmani, Ali; Jafari, Mohamad; Miremadi, Seyed Sohrab

    2011-06-01

    This paper describes implementation of a high-speed encryption algorithm with high throughput for encrypting the image. Therefore, we select a highly secured symmetric key encryption algorithm AES(Advanced Encryption Standard), in order to increase the speed and throughput using pipeline technique in four stages, control unit based on logic gates, optimal design of multiplier blocks in mixcolumn phase and simultaneous production keys and rounds. Such procedure makes AES suitable for fast image encryption. Implementation of a 128-bit AES on FPGA of Altra company has been done and the results are as follow: throughput, 6 Gbps in 471MHz. The time of encrypting in tested image with 32*32 size is 1.15ms.

  5. Lunar sample analysis. [X-ray photoemission and Auger spectroscopy of lunar glass

    NASA Technical Reports Server (NTRS)

    Housley, R. M.; Grant, R. W.; Cirlin, E. H.

    1979-01-01

    The surface composition of two samples from the highly shocked, glass-coated lunar basalt (12054) and from four glass-coated fragments from the 1-2 mm (14161) fines were examined by X-ray photoemission spectroscopy to determine whether the agglutination process itself is responsible for the difference between their surface and bulk compositions. Auger electron spectroscopy of glass balls from the 15425 and 74001 fines were analyzed to understand the nature, extent, and behavior of volatile phases associated with lunar volcanism. Initial results indicate that (1) volatiles, in the outer few atomic layers sampled, vary considerably from ball to ball; (2) variability over the surface of individual balls is smaller; (3) the dominant volatiles on the balls are S and Zn; and (4) other volatiles commonly observed are P, Cl, and K.

  6. Summary of detection, location, and characterization capabilities of AE for continuous monitoring of cracks in reactors

    SciTech Connect

    Hutton, P.H.; Kurtz, R.J.; Friesel, M.A.; Pappas, R.A.; Skorpik, J.R.; Dawson, J.F.

    1984-10-01

    The objective of the program is to develop acoustic emission (AE) methods for continuous monitoring of reactor pressure boundaries to detect and evaluate crack growth. The approach involves three phases: develop relationships to identify crack growth AE signals and to use identified crack growth AE data to estimate flaw severity; evaluate and refine AE/flaw relationships through fatigue testing a heavy section vessel under simulated reactor conditions; and demonstrate continuous AE monitoring on a nuclear power reactor system.

  7. Determination of Minerals in Apples by ICP AES

    NASA Astrophysics Data System (ADS)

    Duxbury, Mark

    2003-10-01

    A laboratory experiment is described that involves the elemental analysis of apples by inductively coupled plasma atomic emission spectroscopy (IICP AES). The results of the experiment allow students to predict the cold-storage stability of apples. During the experiment the sample-preparation techniques and digestion procedures involved in elemental analysis of solid organic samples are introduced and the optimization of the ICP AES is explored. The method detailed can easily be adapted for the analysis of a wider range of elements. The laboratory experiment may also be undertaken using atomic absorption spectroscopy (AAS) with only minor modifications in the sample-preparation procedure.

  8. Manifestation of auger processes in C1 s-satellite spectra of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Brzhezinskaya, M. M.; Pesin, L. A.; Morilova, V. M.; Baitinger, E. M.

    2012-09-01

    Using the equipment of the Russian-German beamline of the synchrotron radiation at the BESSY II electron storage ring, satellite spectra accompanying the C1 s core lines in the cases of single-walled carbon nanotubes and highly ordered pyrolytic graphite have been measured with a high energy resolution. The Auger spectra corresponding to shaking of the valence system of carbon by the core vacancy have been found and investigated. The Auger spectra of the studied single-walled carbon nanotubes and highly ordered pyrolytic graphite are caused by annihilation of the excited π* electron with a hole in the π subband. It has been established that the electron states in the conduction band have 3π* (gT, K, M) symmetry; i.e., they correspond to flat 3π* subband, which is localized by 12-13 eV above the Fermi level. It has been revealed that the general regularities of the distribution of electron states in the valence system insignificantly change during its shake-up by the excited core.

  9. Conceptual design of the AE481 Demon Remotely Piloted Vehicle (RPV)

    NASA Technical Reports Server (NTRS)

    Hailes, Chris; Kolver, Jill; Nestor, Julie; Patterson, Mike; Selow, Jan; Sagdeo, Pradip; Katz, Kenneth

    1994-01-01

    This project report presents a conceptual design for a high speed remotely piloted vehicle (RPV). The AE481 Demon RPV is capable of performing video reconnaissance missions and electronic jamming over hostile territory. The RPV cruises at a speed of Mach 0.8 and an altitude of 300 feet above the ground throughout its mission. It incorporates a rocket assisted takeoff and a parachute-airbag landing. Missions are preprogrammed, but in-flight changes are possible. The Demon is the answer to a military need for a high speed, low altitude RPV. The design methods, onboard systems, and avionics payload are discussed in this conceptual design report along with economic viability.

  10. The Cosmic Ray Energy Spectrum and Related Measurements with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the cosmic ray energy spectrum above 10{sup 18} eV with the Pierre Auger Observatory; (2) The cosmic ray flux observed at zenith angles larger than 60 degrees with the Pierre Auger Observatory; (3) Energy calibration of data recorded with the surface detectors of the Pierre Auger Observatory; (4) Exposure of the Hybrid Detector of The Pierre Auger Observatory; and (5) Energy scale derived from Fluorescence Telescopes using Cherenkov Light and Shower Universality.

  11. Fabrication manual for a reduced-noise auger miner cutting head. Information circular/1984

    SciTech Connect

    Pettitt, M.R.; Aljoe, W.W.

    1984-01-01

    After a long series of laboratory and in-mine tests, a cost-effective, mineworthy, reduced-noise auger miner cutting head was designed, fabricated, and field-tested by Wyle Laboratories under contract to the Bureau of Mines. Compared with standard auger cutting heads, the new heads reduced noise by 10 dBA at the jacksetter's position and by 6 dBA at the operator's position. This report contains detailed fabrication instructions, including engineering drawings, that show how a standard auger cutting head can be modified to produce a reduced-noise auger.

  12. Method to measure gas levels during auger mining of coal. Information circular/1994

    SciTech Connect

    Volkwein, J.C.; Prokop, A.D.

    1994-01-01

    The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sample head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

  13. Astrophysical Sources of Cosmic Rays and Related Measurements with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Correlation of the highest energy cosmic rays with nearby extragalactic objects in Pierre Auger Observatory data; (2) Discriminating potential astrophysical sources of the highest energy cosmic rays with the Pierre Auger Observatory; (3) Intrinsic anisotropy of the UHECR from the Pierre Auger Observatory; (4) Ultra-high energy photon studies with the Pierre Auger Observatory; (5) Limits on the flux of diffuse ultra high energy neutrinos set using the Pierre Auger Observatory; (6) Search for sidereal modulation of the arrival directions of events recorded at the Pierre Auger Observatory; (7) Cosmic Ray Solar Modulation Studies in the Pierre Auger Observatory; (8) Investigation of the Displacement Angle of the Highest Energy Cosmic Rays Caused by the Galactic Magnetic Field; (9) Search for coincidences with astrophysical transients in Pierre Auger Observatory data; and (10) An alternative method for determining the energy of hybrid events at the Pierre Auger Observatory.

  14. Sputter-induced cross-contamination in analytical AES and XPS instrumentation: utilization of the effect for the in situ deposition of ultrathin functional layers.

    PubMed

    Scheithauer, Uwe

    2013-09-01

    Cross-contamination is observed on sample surfaces by Auger electron spectroscopy and X-ray photoelectron spectroscopy if multiple samples are mounted on one sample holder and a neighbouring sample was sputter depth profiling. During sputter depth profiling, sputtered material is deposited on inner surfaces of the instrument. In a secondary sputter process, which is due to species leaving the primary sputter target with higher kinetic energy, the previously deposited material is transported from the inner surfaces to the other samples mounted on the sample holder. This reflective sputtering is utilized to deposit ultrathin layers on sample surfaces for X-ray photoelectron spectroscopy binding energy referencing purposes and to build up ultrathin conductive layers to make possible Auger electron spectroscopy measurements on insulating samples. PMID:23462980

  15. Gravity waves in the thermosphere observed by the AE satellites

    NASA Technical Reports Server (NTRS)

    Gross, S. H.; Reber, C. A.; Huang, F. T.

    1983-01-01

    Atmospheric Explorer (AE) satellite data were used to investigate the spectra characteristics of wave-like structure observed in the neutral and ionized components of the thermosphere. Power spectral analysis derived by the maximum entropy method indicate the existence of a broad spectrum of scale sizes for the fluctuations ranging from tens to thousands of kilometers.

  16. Photoelectron Spectroscopy of Ions: Study of the Auger Decay of the 4d→nf (n=4,5) Resonances in Xe^{5+} Ion.

    PubMed

    Bizau, J-M; Cubaynes, D; Guilbaud, S; Penent, F; Lablanquie, P; Andric, L; Palaudoux, J; Al Shorman, M M; Blancard, C

    2016-03-11

    We have studied, for the first time by electron spectroscopy, the Auger decay of the 4d→nf (n=4,5) resonances in Xe^{5+} ion. By detecting in coincidence the Auger electrons with the resulting Xe^{6+} ions, we unravel the contribution of the different final ionic states to the total cross section measured by ion spectroscopy. A strong intensity of 5s5p satellite lines has been observed, up to 4 times stronger than the 5s^{2} main lines. This unexpected behavior is confirmed by multiconfiguration Dirac-Fock calculations. This technique provides the most stringent test for theoretical models and allows us to disentangle the contribution of ions in the ground and metastable states in the target beam. PMID:27015477

  17. Complex multireference configuration interaction calculations for the K-vacancy Auger states of N(q+) (q = 2-5) ions.

    PubMed

    Peng, Yi-Geng; Wu, Yong; Zhu, Lin-Fan; Zhang, Song Bin; Wang, Jian-Guo; Liebermann, H-P; Buenker, R J

    2016-02-01

    K-vacancy Auger states of N(q+) (q = 2-5) ions are studied by using the complex multireference single- and double-excitation configuration interaction (CMRD-CI) method. The calculated resonance parameters are in good agreement with the available experimental and theoretical data. It shows that the resonance positions and widths converge quickly with the increase of the atomic basis sets in the CMRD-CI calculations; the standard atomic basis set can be employed to describe the atomic K-vacancy Auger states well. The strong correlations between the valence and core electrons play important roles in accurately determining those resonance parameters, Rydberg electrons contribute negligibly in the calculations. Note that it is the first time that the complex scaling method has been successfully applied for the B-like nitrogen. CMRD-CI is readily extended to treat the resonance states of molecules in the near future. PMID:26851920

  18. Electron-beam-induced deposition and post-treatment processes to locally generate clean titanium oxide nanostructures on Si(100).

    PubMed

    Schirmer, M; Walz, M-M; Vollnhals, F; Lukasczyk, T; Sandmann, A; Chen, C; Steinrück, H-P; Marbach, H

    2011-02-25

    We have investigated the lithographic generation of TiO(x) nanostructures on Si(100) via electron-beam-induced deposition (EBID) of titanium tetraisopropoxide (TTIP) in ultra-high vacuum (UHV) by scanning electron microscopy (SEM) and local Auger electron spectroscopy (AES). In addition, the fabricated nanostructures were also characterized ex situ via atomic force microscopy (AFM) under ambient conditions. In EBID, a highly focused electron beam is used to locally decompose precursor molecules and thereby to generate a deposit. A drawback of this nanofabrication technique is the unintended deposition of material in the vicinity of the impact position of the primary electron beam due to so-called proximity effects. Herein, we present a post-treatment procedure to deplete the unintended deposits by moderate sputtering after the deposition process. Moreover, we were able to observe the formation of pure titanium oxide nanocrystals (<100 nm) in situ upon heating the sample in a well-defined oxygen atmosphere. While the nanocrystal growth for the as-deposited structures also occurs in the surroundings of the irradiated area due to proximity effects, it is limited to the pre-defined regions, if the sample was sputtered before heating the sample under oxygen atmosphere. The described two-step post-treatment procedure after EBID presents a new pathway for the fabrication of clean localized nanostructures. PMID:21242619

  19. Electron-beam-induced deposition and post-treatment processes to locally generate clean titanium oxide nanostructures on Si(100)

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Walz, M.-M.; Vollnhals, F.; Lukasczyk, T.; Sandmann, A.; Chen, C.; Steinrück, H.-P.; Marbach, H.

    2011-02-01

    We have investigated the lithographic generation of TiOx nanostructures on Si(100) via electron-beam-induced deposition (EBID) of titanium tetraisopropoxide (TTIP) in ultra-high vacuum (UHV) by scanning electron microscopy (SEM) and local Auger electron spectroscopy (AES). In addition, the fabricated nanostructures were also characterized ex situ via atomic force microscopy (AFM) under ambient conditions. In EBID, a highly focused electron beam is used to locally decompose precursor molecules and thereby to generate a deposit. A drawback of this nanofabrication technique is the unintended deposition of material in the vicinity of the impact position of the primary electron beam due to so-called proximity effects. Herein, we present a post-treatment procedure to deplete the unintended deposits by moderate sputtering after the deposition process. Moreover, we were able to observe the formation of pure titanium oxide nanocrystals (<100 nm) in situ upon heating the sample in a well-defined oxygen atmosphere. While the nanocrystal growth for the as-deposited structures also occurs in the surroundings of the irradiated area due to proximity effects, it is limited to the pre-defined regions, if the sample was sputtered before heating the sample under oxygen atmosphere. The described two-step post-treatment procedure after EBID presents a new pathway for the fabrication of clean localized nanostructures.

  20. Supraphysiologic levels of the AML1-ETO isoform AE9a are essential for transformation.

    PubMed

    Link, Kevin A; Lin, Shan; Shrestha, Mahesh; Bowman, Melissa; Wunderlich, Mark; Bloomfield, Clara D; Huang, Gang; Mulloy, James C

    2016-08-01

    Chromosomal translocation 8;21 is found in 40% of the FAB M2 subtype of acute myeloid leukemia (AML). The resultant in-frame fusion protein AML1-ETO (AE) acts as an initiating oncogene for leukemia development. AE immortalizes human CD34(+) cord blood cells in long-term culture. We assessed the transforming properties of the alternatively spliced AE isoform AE9a (or alternative splicing at exon 9), which is fully transforming in a murine retroviral model, in human cord blood cells. Full activity was realized only upon increased fusion protein expression. This effect was recapitulated in the AE9a murine AML model. Cotransduction of AE and AE9a resulted in a strong selective pressure for AE-expressing cells. In the context of AE, AE9a did not show selection for increased expression, affirming observations of human t(8;21) patient samples where full-length AE is the dominant protein detected. Mechanistically, AE9a showed defective transcriptional regulation of AE target genes that was partially corrected at high expression. Together, these results bring an additional perspective to our understanding of AE function and highlight the contribution of oncogene expression level in t(8;21) experimental models. PMID:27457952