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Sample records for auger electron spectroscopy

  1. Auger electron spectroscopy

    International Nuclear Information System (INIS)

    General features of electron excited Auger electron spectroscopy (AES) which is a nondestructive technique for the analysis of surfaces upto about 15 Adeg depth with a detection limit of about 0.1% of a monolayer. Methods of measuring the Auger electron energies and recent improvements in the instrumentation are reviewed. Typical energy resolution is found to be about 0.5% which is specially suited for the detection of light elements. It is widely used in metallurgy, surface chemistry and thin film studies. (K.B.)

  2. Auger electron spectroscopy of alloys

    International Nuclear Information System (INIS)

    This thesis describes how the surface compositions of some alloys can be determined by Auger Electron Spectroscopy (AES). The motivation for this research and the reasons for the choice of alloy systems studied are formulated. The theoretical background of AES is briefly discussed and the apparatus used and the experimental procedures applied are described. Four alloy systems have been investigated in this thesis - Ni-Cu and Pd - Ag (consisting of a component active in most cataytic reactions - Ni and Pd; and a component which is almost inactive for a number of reactions - Cu and Ag) and Pt - Pd and Pt-Ir (consisting of two active components). Knowledge of the surface composition of the various alloy systems is shown to be essential for the interpretation of catalytic results. (Auth./C.F.)

  3. Photoelectron spectroscopy and Auger electron spectroscopy of solids and surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, S.P.

    1976-01-01

    The use of photoelectron spectroscopy, primarily x-ray photoelectron spectroscopy, to obtain information on the electronic structure of a wide variety of solids (especially the bulk electronic structure of solids) is covered. Both valence band and core-level spectra, as well as a few cases of photon excited Auger electron spectroscopy, are employed in the investigations to derive information on N(E). The effect of several modulations inherent in the measured I(E)'s, such as final state band structure, cross section, and relaxation, is discussed. Examples of many-electron interactions in PES are given. Some experimental aspects of PES and AES studies are given with emphasis on sample preparation techniques. Multiple splitting of core levels is examined using the Mn levels in MnF/sub 2/ as a detailed case study. Core level splittings in transition metals, rare earth metals, transition metal halides and several alloys are also reported. The application of PES to the study of the chemical bond in some crystalline semiconductors and insulators, A/sup N/B/sup 8-N/ and A/sup N/B/sup 10-N/ compounds is treated, and a spectroscopic scale of ionicity for these compounds is developed from the measured ''s-band'' splitting in the valence band density of states. (GHT)

  4. Photoelectron spectroscopy and Auger electron spectroscopy of solids and surfaces

    International Nuclear Information System (INIS)

    The use of photoelectron spectroscopy, primarily x-ray photoelectron spectroscopy, to obtain information on the electronic structure of a wide variety of solids (especially the bulk electronic structure of solids) is covered. Both valence band and core-level spectra, as well as a few cases of photon excited Auger electron spectroscopy, are employed in the investigations to derive information on N(E). The effect of several modulations inherent in the measured I(E)'s, such as final state band structure, cross section, and relaxation, is discussed. Examples of many-electron interactions in PES are given. Some experimental aspects of PES and AES studies are given with emphasis on sample preparation techniques. Multiple splitting of core levels is examined using the Mn levels in MnF2 as a detailed case study. Core level splittings in transition metals, rare earth metals, transition metal halides and several alloys are also reported. The application of PES to the study of the chemical bond in some crystalline semiconductors and insulators, A/sup N/B/sup 8-N/ and A/sup N/B/sup 10-N/ compounds is treated, and a spectroscopic scale of ionicity for these compounds is developed from the measured ''s-band'' splitting in the valence band density of states

  5. Effective applications of auger electron spectroscopy

    International Nuclear Information System (INIS)

    The goal of this study is to explore different aspects of the AES process and to present the new techniques which can be used effectively for analytical purposes. More emphasis is given to AES data acquisition, sensitivity factor and Auger intensity. The experimental details of a typical scanning Auger microprobe (SAM) is also presented. Applications of AES to selected systems such as microelectronic devices, superconductors, an in metallurgy are described

  6. Defect identification by compositional defect review using auger electron spectroscopy

    International Nuclear Information System (INIS)

    Defect identification plays an enabling role in determining the source of particles that occur during semiconductor processing and are subsequently detected by defect inspection tools. Auger electron spectroscopy provides a high spatial resolution, surface sensitive analytical probe that is well matched to examining small, thin or complex defects. A focused ion beam (FIB) can be used to cross-section buried defects and structures for subsequent Auger analysis. Such measurements have been made on defects from two wafers pulled at different process steps. One wafer was analyzed after poly-Si deposition, and the other wafer was analyzed after metal 2 etch. The defects on the poly-Si wafer are Si particles. Three types of particles were found on the metal 2 wafer: C-based, stainless steel, and Si-oxide. The majority of defects on this wafer are C-based. Auger, EDS and FIB results will be compared for representative defects on these two wafers

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

    Science.gov (United States)

    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.

  8. Application of Auger electron spectroscopy in studies about diffusion of Cu in thin Ni films

    International Nuclear Information System (INIS)

    The diffusion coefficient of Cu in thin Ni films (350A) at low temperatures is determined by using Auger electron spectroscopy and timepermeation technic. A grain-boundary mechanism is proposed for the diffusion of Cu in Ni. The activation energy is determined to Q=0,6eV. (Author)

  9. Auger spectroscopy and surface analysis

    International Nuclear Information System (INIS)

    In 1925 Pierre Auger reported on his observations of low energy electrons associated with core-ionised atoms in cloud chamber experiments. He was able to correctly identify the mechanism for their production, and such electrons are now known as Auger electrons. Typically Auger electrons have energies in the range 10 eV to 2 keV. The short distance that such low energy electrons travel in solids ensures that Auger electrons come from the surface layers. The data generated by the AES technique are complex. There are at least three electrons involved in the process, and there are many possible configurations for the atom. These possibilities led to spectra that are not readily interpreted in detail. Theory lags behind experiment in this area. In principle, it should be possible to find information about the chemical environment of atoms from Auger spectra. While there are clear changes in spectral lineshapes, there is no simple way to go from the spectra to an understanding of the chemical bonding of the atom. There are a number of experiments currently underway which aim to improve our understanding of the Auger process. Synchrotron experiments with tunable energy x-rays are providing new insight. Experiments that use positrons to excite Auger emission have also produced further recent understanding. Coincidence experiments between photoelectrons and Auger electrons have also made recent advances. Auger photoelectron coincidence spectroscopy reduces the complexity of Auger spectra by only counting those electrons that occur as a consequence of selected ionizations. The effect is to reduce the complexity of the spectra, and to isolate processes that are often clouded by the simultaneous occurrence of other effects. (author)

  10. Auger electron spectroscopy and electron energy loss spectroscopy studies on carbonization of Si(100) and (111) surfaces with ethylene

    International Nuclear Information System (INIS)

    The reactions of Si(100) and Si(111) surfaces at 700 deg. C (973 K) with ethylene (C2H4) at a pressure of 1.3x10-4 Pa for various periods of time were studied by using Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS). For a C2H4 exposure level, the amount of C on the (111) surface was larger than that on the (100) surface. The formation of β-SiC grain was deduced by comparing the CKLL spectra from the sample subjected to various C2H4 exposure levels, and from β-SiC crystal

  11. Study of the stepwise oxidation and nitridation of Si(111): Electron stimulated desorption, Auger spectroscopy, and electron loss spectroscopy

    International Nuclear Information System (INIS)

    Electron stimulated desorption, Auger line shape analysis, and electron loss spectroscopy measurements are reported for the electron activated stepwise oxidation and nitridation of the Si(111) surface. In ESD it is found that appreciable levels of surface hydrogen can be present which can lead to hydroxyl formation upon oxidation. The hydroxyl rich films are unstable in an electron beam, while surfaces oxidized with activated oxygen, where no OH is formed, are much more stable. The nitrided films are always stable in the electron beam even though there too hydrogen is always found. On the OH-free oxide, ESD shows two chemically distinct O species, one thought to be SiO2 and the other adsorbed O2 or a chemical intermediate. The Si(L23VV) Auger spectra for both the oxide and nitride are treated by background subtraction, integration, deconvolution, and subtraction of the elemental part of the spectrum, as a function of reaction time over a well controlled series of reaction steps. The Auger spectra for both oxide and nitride films suggest that in the earliest stages of reaction, the reacted film is made up of low coordination intermediates which gradually evolve to the stoichiometric compound as the coordination increases. In loss spectroscopy, both the Si(L23) core loss and the near elastic loss were measured. The L23 core loss shows the same gradual evolution to the oxide seen in the Auger results, with an intermediate oxidation state dominating in the early stages of reaction. The near elastic loss spectra, by contrast, quickly saturate in the early stages of reaction to the final oxide spectrum which is characterized by features both of the full oxide and a suboxide. Similar results are found for the nitride

  12. Surface sensitivity of Auger-electron spectroscopy and X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    A convenient measure of surface sensitivity in Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) is the mean escape depth (MED). If the effects of elastic-electron scattering are neglected, the MED is equal to the electron inelastic mean free path (IMFP) multiplied by the cosine of the emission angle with respect to the surface normal, and depends on the material and electron energy of interest. An overview is given here of recent calculations of IMFPs for 50-2000 eV electrons in a range of materials. This work has led to the development of a predictive formula based on the Bethe equation for inelastic electron scattering in matter from which IMFPs can be determined. Estimates show, however, that elastic-electron scattering can significantly modify the MED. Thus, for AES, the MED will be reduced by up to about 35%. For XPS, however, the MED can be changed by up to ±30% for common measurement conditions although it can be much larger (by up to a factor of 2) for near-grazing emission angles. Ratios of MED values, calculated with elastic scattering considered and neglected for XPS from the 3s, 3p, and 3d subshells of silver with Mg Kα X-rays are approximately constant (to about 10%) over a range of emission angles that varies from 40 to 60 depending on the subshell and the angle of X-ray incidence. Recommendations are given on how to determine the optimum range of emission angles for satisfactory analysis of angle-resolved XPS (ARXPS) data. Definitions are included of three terms often used for describing surface sensitivity (IMFP, MED, and effective attenuation length (EAL)), and examples are given of the varying magnitudes of these quantities for different analytical conditions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  13. Electronic structure of quasicrystals deduced from Auger and x-ray photoelectron spectroscopies

    International Nuclear Information System (INIS)

    Specific features in the electronic structure of Al-transition metal quasicrystals are analysed by a combination of Auger and x-ray photoelectron spectroscopies. We first demonstrate that different degrees of asymmetry in the transition metals' 2p core-level lineshape observed across different types of surface structure correspond to variations in the density of states at the Fermi level, DOS(EF). Using this effect, we explore the controversial issue of whether the quasicrystalline, decagonal AlNiCo system is electronically stabilized. We find strong evidence for the presence of a reduced DOS(EF) in this system, as expected for electronically stabilized compounds, and as observed in the quasicrystalline, icosahedral AlPdMn and AlCuFe alloys. Finally, qualitative information on the nature of the electronic states in quasiperiodic structures extracted from the core-valence-valence Auger lines are presented and discussed. (author)

  14. Atomic and molecular photoelectron and Auger-electron-spectroscopy studies using synchrotron radiation

    International Nuclear Information System (INIS)

    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 also 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 of the ejected electrons. The double-angle-TOF method for the measurement of photoelectron angular distributions is discussed. This technique offers the advantages of increased electron collection efficiency and the elimination of certain systematic errors. An electron spectroscopy study of inner-shell photoexcitation and ionization of Xe, photoelectron angular distributions from H2 and D2, and photoionization cross sections and photoelectron asymmetries of the valence orbitals of NO are reported

  15. Quantum-beat Auger spectroscopy

    CERN Document Server

    Zhang, Song Bin

    2015-01-01

    The concept of nonlinear quantum-beat pump-probe Auger spectroscopy is introduced by discussing a relatively simple four-level model system. We consider a coherent wave packet involving two low-lying states that was prepared by an appropriate pump pulse. This wave packet is subsequently probed by a weak, time-delayed probe pulse with nearly resonant coupling to a core-excited state of the atomic or molecular system. The resonant Auger spectra are then studied as a function of the duration of the probe pulse and the time delay. With a bandwidth of the probe pulse approaching the energy spread of the wave packet, the Auger yields and spectra show quantum beats as a function of pump-probe delay. An analytic theory for the quantum-beat Auger spectroscopy will be presented, which allows for the reconstruction of the wave packet by analyzing the delaydependent Auger spectra. The possibility of extending this method to a more complex manifold of electronic and vibrational energy levels is also discussed.

  16. X-ray photoelectron and X-ray Auger electron spectroscopy studies of heavy ion irradiated C60 films

    International Nuclear Information System (INIS)

    The influence of 200 MeV Au ion irradiation on the surface properties of polycrystalline fullerene films has been investigated. The X-ray photoelectron and X-ray Auger electron spectroscopies are employed to study the ion-induced modification of the fullerene, near the surface region. The shift of C 1s core level and decrease in intensity of shake-up satellite were used to investigate the structural changes (like sp2 to sp3 conversion) and reduction of π electrons, respectively, under heavy ion irradiation. Further, X-ray Auger electron spectroscopy was employed to investigate hybridization conversion qualitatively as a function of ion fluence

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

    Energy Technology Data Exchange (ETDEWEB)

    Arp, U. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Electron and Optical Physics Div.; LeBrun, T.; Southworth, S.H.; Jung, M. [Argonne National Lab., IL (United States). Physics Div.; MacDonald, M.A. [E.P.S.R.C. Daresbury Lab., Warrington (United Kingdom)

    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.

  18. Auger electron spectroscopy of oxidized titanium overlayers: Speciation of homogeneous and heterogenous samples

    International Nuclear Information System (INIS)

    Auger electron spectroscopy (AES) is often used for the determination of the quantitative composition and the speciation of the materials under investigation. The present work illustrates the quantitative analysis of titanium oxides and its application to the characterization of a partially oxidized titanium overlayer on top of a copper substrate. The quantfication procedure described provides an average composition of the surface area investigated. Care has to be taken to convert this composition into an information about the chemical species present at the sample surface because the observed fine structures of the AES spectra cannot be correlated unambiguously with the chemical species present. The AES spectra are not suited to distinguish conclusively between a homogeneous composition of the analyzed volume and the presence of a mixture of several titanium species. Additional information is required for a final distinction between the two possibilities, which can be achieved, for example, by X-ray photoelectron spectroscopy (XPS). (orig.)

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

    International Nuclear Information System (INIS)

    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 in order to determine the types of surface changes leading to the improved friction and wear behaviour 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 behaviour. 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. (author)

  20. Scanning Auger electron spectroscopy studies of grain-boundary segregation in Type 304 stainless steel

    International Nuclear Information System (INIS)

    Scanning Auger electron spectroscopy studies have been conducted on grain-boundary surfaces of Type 304 stainless steel that were fractured in situ. To enhance the probability of intergranular fracture, the specimens were first subjected to creep deformation for 1000 h at 7000C. A semiquantitative surface chemical composition was calculated from the peak heights of Auger electron spectra. The concentration of Cr at the fracture surface was not different from the bulk value. This indicates that the long-term heat treatment caused healing of the sensitization. The concentrations of S, C, and Si at the fracture surface were at least an order of magnitude higher than the bulk values. Chemical composition profiles obtained by ion-sputtering indicated that segregation of S, C, P, and Si occurred within a depth of several atomic monolayers from the grain-boundary surface. Mo, Mn and Cu were not detected. The concentrations of Ni and Fe are in good agreement with the bulk chemical analysis

  1. Sputtering measurements on controlled thermonuclear reactor materials using Auger electron spectroscopy

    International Nuclear Information System (INIS)

    Simultaneous auger electron spectroscopy and ion sputtering have been used to measure the sputter yield, S (atom/ion), for Ar+ on carbon, tungsten, niobium, and silver in the energy range from 0.5 to 1.5 keV and for H+ on tungsten, carbon, and silver at 11 keV. All measurements were performed on thin films, ranging in thickness from 150 to 6000 A, which were maintained at room temperature during bombardment. These films were produced by vacuum vapor deposition, and the thicknesses were measured by surface profilometry. The auger electron signals were used to determine the time required to etch through a film; from these measurements and a knowledge of the ion current density, the sputter yield was determined. For Ar+, 0.7 less than or equal to S less than or equal to 5.1 and for H+, 0.004 less than or equal to S less than or equal to 0.04 for the various materials studied in this energy range. Agreement with earlier experimental results is generally within +-25 percent

  2. The characterisation of non-evaporable getters by Auger electron spectroscopy Analytical potential and artefacts

    CERN Document Server

    Scheuerlein, C; Taborelli, M

    2002-01-01

    The surfaces of getter materials are particularly difficult to analyse because of their high chemical reactivity. The results obtained can be strongly influenced by the experimental set-up and procedures. In this paper the experimental influence on the Auger electron spectroscopy results is discussed, based on the measurements of more than 100 different non-evaporable getter (NEG) materials. There are four typical changes in the Auger electron spectra when a NEG becomes activated. The oxygen peak intensity decreases, the shape of the metal peaks changes, the carbon peak shape changes shape and intensity and a chlorine peak occurs. All these changes are affected by instrumental artefacts. The Zr-MNV peak shape changes occurring during the reduction of ZrO2 are well suited to determine the onset of NEG activation, while the slope with which the O-KLL peak intensity decreases in a certain temperature range is a better criterion for the determination of the temperature at which activation is complete. The O-KLL i...

  3. Auger electron spectroscopy applied to inner shell ionization by fast charged particles

    International Nuclear Information System (INIS)

    Until recently, inner shell ionization by charged particle impact was studied almost exclusively through the use of x-ray spectroscopy. This method is limited in accuracy, however, for ionization of inner shells where the fluorescence yield is small. For K-shell ionization of elements with atomic number less than about ten the fluorescence yield can be considered negligible and Auger electron emission cross section provide direct information regarding the ionization cross section. The ionization cross sections determined in this way are accurate to approximately 20 percent whereas x-ray measurements may be uncertain by a factor of five or more due to uncertainties in fluorescence yields. In addition to ionization cross sections, Auger emission spectra provide information regarding multiple ionization, effects of molecular binding on inner shell ionization and, when coupled with x-ray measurements, provide fluorescence yields as a function of the final state of the target atom. These points will be illustrated for ionization by fast protons along with some results for heavier incident particles

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. The Low Energy Auger Electron Spectroscopy Lines as an Index of the Ba Overlayer Order on the Ni(110 Surface

    Directory of Open Access Journals (Sweden)

    D. Vlachos

    2014-01-01

    Full Text Available We investigate the interaction of Ba with the Ni(110 surface at elevated temperatures by means of Auger electron spectroscopy and low energy electron diffraction. The results show that annealing of the substrate causes desorption and ordering of the initially amorphous overlayer, resulting in c(2×2 and (2×2 structures. It is observed that the induced ordering crucially affects the lineshape of the double Auger transition line Ba(73 eVN45O23P1, establishing this line as an index of ordering of the Ba overlayer. The underlying physics of this effect is discussed.

  6. Secondary electron yield and Auger electron spectroscopy measurements on oxides, carbide, and nitride of niobium

    International Nuclear Information System (INIS)

    Secondary electron yield measurements before and after Ar ion sputtercleaning were made on Nb and Nb compounds of interest for rf superconductingcavities. Total secondary electron yields (sigma) for primary energies 20--1500 eV were measured for solid Nb (sigma/sub max/ = 1.3 at 300 eV), anodized Nb2O5 (sigma/sub max/ = 1.2 at 300 eV), and powders of Nb(sigma/sub max/ = 1.0 at 400 eV), NbO (sigma/sub max/ = 0.9 at 400 eV), NbO2 (sigma/sub max/ = 1.0 at 400 eV), Nb2O5 (sigma/sub max/ = 0.95 at 400 eV), NbC(sigma/sub max/ = 0.8 at 400 eV), and NbN (sigma/sub max/ = 0.8 at 500 eV). Determinations were made for Auger elemental sensitivities, and the relationship between Auger peak heights and oxide stoichiometry is discussed. The sputter etch rate of anodized Nb2O5 was measured by depth profiling anodic coatings of known thickness

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

    Science.gov (United States)

    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. Quantitative auger electron spectroscopy of the interface carbon layer formation on the vacuum cleavage surfaces of layered semiconductor In4Se3 crystals

    International Nuclear Information System (INIS)

    The results of the qualitative Auger electron spectroscopy of the interface carbon layer formation on the high vacuum cleavage surfaces of layered semiconductor In4Se3 crystals are presented. The kinetics of interfacial carbon layer formation on the cleavage surfaces of crystals and the elemental and phase composition of the interface dependent on the exposition time in high vacuum and on the dose of electron irradiation have been studied by the quantitative Auger electron and mass-spectroscopy methods

  9. Investigation of grain boundary chemistry in Al-Li 2195 welds using Auger electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J.H. [National Aeronautics and Space Administration, Huntsville, AL (United States). George C. Marshall Space Flight Center

    1996-05-01

    Al-Li alloy 2195 is a low-density material with high fracture toughness that is particularly well-suited for aerospace systems. It will replace Al-Cu alloy 2219 in the Super Light Weight Tank (SLWT), a modified version of the external tank being developed for the Space Shuttle to support Space Station deployment. Recent efforts have focused on joining 2195 with variable polarity plasma arc welding, as well as repairing 2195 welds with tungsten inert gas techniques. During this study, Auger electron spectroscopy (AES) was used to examine grain boundary chemistry in 2195 welds. Results indicated that weld integrity depends on whether (and how much) the grain boundaries are covered with thin films comprised of a mixture of discontinuous Al{sub 2}O{sub 3} in Al (Al/Al{sub 2}O{sub 3}), which form during weld solidification. O was probably introduced as a contaminant in the shielding gases, occurring at low levels considered negligible for Al alloys that do not contain Li. However, oxidation kinetics in 2195 are increased by Li enrichment of small quantities of Al{sub 2}O{sub 3}, further enhancing thin film formation at the grain boundaries. Al{sub 2}O{sub 3} can ultimately occupy sufficient grain boundary area to degrade the material`s mechanical properties, producing negative effects that are compounded by the cumulative heat input of multi-pass repair welding. (orig.)

  10. Study of the stepwise oxidation and nitridation of Si(111) by electron stimulated desorption and Auger spectroscopy

    International Nuclear Information System (INIS)

    Electron stimulated desorption (ESD) and Auger electron spectroscopy (AES) measurements are reported for the electron-activated stepwise oxidation and nitridation of the Si(111) surface. In ESD it is found that appreciable levels of surface hydrogen are present which can lead to hydroxyl formation upon oxidation. The hydroxyl-rich films are unstable in an electron beam, while surfaces oxidized with activated O2, where no OH is formed, are much more stable. On the OH-free oxide, ESD shows two chemically distinct O species, one thought to be SiO2 and the other either adsorbed O2 or a chemical intermediate. The Auger spectra for both oxide and nitride films, which show a continual change from Si to Si-compound nature, suggests that in the earliest stages of reaction the reacted film is made up mainly of low coordination intermediates which gradually evolve to the full compound as the coordination increases

  11. Surface change in titanium between 25 and 10000C studied by Auger electron spectroscopy and x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    The dissolution of native oxides on titanium were studied over the temperature range 25 to 10000C to determine their role in the pyrotechnic reaction of titanium with potassium perchlorate. From Auger electron spectroscopy (AES) data it was found that the solubility of the oxide in Ti increased sharply at 3500C. High resolution AES scans of the Ti LMM transitions as well as x-ray photoelectron spectroscopy (XPS) scans of the Ti 2p level showed that free Ti is present at the surface above 3500C. The O ls XPS data show that the surface contains hydroxyl as well as oxide groups. The hydroxide-to-oxide ratio begins to decrease below 2500C, and at 4500C the remaining oxygen is found predominantly as oxide. In addition, the XPS data show that the dissolution process proceeds through the formation of titanium suboxides. These AES and XPS results complement physical property measurements that have also been made on the Ti/KC1O4 mixture. Physical property measurements show that 1) below 3000C no reaction occurs, and 2) just above 3000C an exothermic reaction occurs, corresponding to the reaction of fresh titanium with atmospheric oxygen. The fixed temperature studies at 3000C and 3500C have shown that there is a semilogarithmic relationship between the surface oxygen level and the time at temperature

  12. A study of quantitative chemical state analysis on cerium surface by using auger electron spectroscopy and factor analysis

    International Nuclear Information System (INIS)

    A reaction with oxygen during oxygen exposure to Cerium metal surface under ultra high vacuum condition and depth profiling on formed Cerium oxide layer were investigated in term of chemical state analysis by Auger electron spectroscopy (AES) and by factor analysis. Principal component analysis (PCA) on Ce NON Auger spectra suggested that three physically meaningful components existed from the analyzed data in both cases. After the PCA, three spectra were extracted from the data and these showed significant peak shape changes in each spectrum which were corresponding to different chemical states. In addition, the profiles constructed by factor analysis showed the chemical state changes on the Cerium metal surface during oxidation or chemical depth distributions in the oxide layer. (author)

  13. Auger electron spectroscopy depth profile study in fracture surfaces of sinterized YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Auger electron spectroscopy depth profiles from different surfaces of the YBa2Cu3O7-x polycrystalline compound, such as fracture and polished fracture surface of sintered ceramics, fracture of isostatically pressed powder and powder surface, have been measured. For the first time in this material, a study of the apparent enrichments in the Auger profiles compared with a preferential sputtering model in nonsimple oxides, recently tested in other perovskite oxide compound, is reported. These data show an oxygen surface release and an intergrain copper enrichment as consequence of thermal processing of the material. Thus, the existence of different stoichiometry in the grain boundaries as an additional contribution to the formation of weak links appears confirmed

  14. Auger electron spectroscopy study on the characterization and stability of the Cu9Al4/TiN/Si system

    International Nuclear Information System (INIS)

    Diffusion barrier properties of TiN films to silicon and the Cu9Al4 compound have been studied using Auger electron spectroscopy. The experimental results indicate that the TiN layer of 800A is effective as a diffusion barrier at 670degC. It is found that the reaction of Al in the compound with Ti in the barrier results in the failure of the system due to intermixing of elements at 700degC. The failure temperature of 700degC, which is higher than that of aluminum or copper metallization, is due to the stability of the Cu9Al4 compound itself. (author)

  15. Auger electron spectroscopy in sputtering measurements: Application to low-energy Ar+ sputtering of Ag and Nb

    International Nuclear Information System (INIS)

    The sputtering of Ag and Nb by Ar+ in the energy range from 0.5 to 1.5 keV has been measured. The agreement with extant data, where available, is good. The experimental technique is a new adaptation of certain earlier methods and employs Auger electron spectroscopy of a continuously sputtered area of a thin-film composite structure, produced by vapor deposition. This new method should permit very low sputter yields (Sapproximately-less-than10-3) to be measured in subsequent experiments

  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

    Science.gov (United States)

    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. Electronic many-body effects at metal-organic interfaces studied with PES, NEXAFS and resonant Auger Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Haeming, M.; Schoell, A.; Reinert, F. [Universitaet Wuerzburg, Experimentelle Physik VII, D-97074 Wuerzburg (Germany); Umbach, E. [Karlsruhe Institut fuer Technologie (KIT) D-76021 Karlsruhe (Germany)

    2011-07-01

    Electronic many-body and correlation effects have been studied intensively at transition metal compounds with localized d/f electrons. They are related to interesting material properties, e.g. Mott metal-insulator transitions, charge transfer satellites and superconductivity. Recent investigations of graphene,{sup 1} C{sub 60},{sup 2} and TTF-TCNQ{sup 3} showed that many-body effects can also be important for organic thin films. We have investigated several organic thin films (PTCDA, PTCDI, BTCDA, BTCDI, SnPc) deposited on a Ag(111) surfaces with photoelectron spectroscopy, NEXAFS and resonant Auger Raman spectroscopy. Our data provide significant indications for electronic many-body effects involving substrate-adsorbate charge transfer, which can be understood by concepts developed for charge transfer compounds. These results give insight into new, interesting aspects of physics at metal-organic interfaces. {sup 1} I.

  18. Graphite oxide Auger-electron diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Mikoushkin, V.M., E-mail: V.Mikoushkin@mail.ioffe.ru [Ioffe Institute, 194021 Saint-Petersburg (Russian Federation); Kriukov, A.S.; Shnitov, V.V.; Solonitsyna, A.P.; Fedorov, V.Yu.; Dideykin, A.T.; Sakseev, D.A. [Ioffe Institute, 194021 Saint-Petersburg (Russian Federation); Vilkov, O.Yu. [St. Petersburg State University, 198504 St. Petersburg (Russian Federation); Lavchiev, V.M. [Institute for Microelectronics and Microsensors, Johannes Kepler University, A-4040 Linz (Austria)

    2015-02-15

    Highlights: • Very large graphite oxide (GO) flakes (∼100 μm) were studied by AES and XPS. • Auger energies for the GO main functional groups were obtained for the first time. • AES technique for determining the GO chemical/elemental composition was developed. • The developed technique gives concentration of chemically bound hydrogen. • The developed technique provides information on the GO surface and bulk. - Abstract: Graphite oxide (GO) nanofilms on the SiO{sub 2}/Si surface have been studied by photoelectron spectroscopy (XPS) with synchrotron radiation and by Auger electron spectroscopy (AES). Auger electron energies were determined for the basic functional GO groups: hydroxyl (C−OH) and epoxide (C−O−C). The data obtained enabled developing a technique for the GO chemical and elemental composition determination. The technique allows controlling the hydrogen content in GO despite the impossibility of Auger emission from hydrogen.

  19. Auger electron spectroscopy of the surface of a pipe-like solid C60+18n

    International Nuclear Information System (INIS)

    Auger and electron energy loss spectra obtained when probing the surface of nanofiber carbon material by an electron beam point out to C60 football-type of covers with the outlet to the surface of nanopipe carbon molecules

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

    Science.gov (United States)

    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

  1. Characterisation of the surface over-layer of welded uranium by FIB, SIMS and Auger electron spectroscopy

    International Nuclear Information System (INIS)

    Secondary ion mass spectrometry (SIMS), focused ion beam (FIB) milling and Auger electron spectroscopy have been used to examine the composition and surface structure of uranium welded by an electron beam. Four characteristic areas of the metal surface were designated, these being: body (unaffected by the welding process), heat affected zone (HAZ), weld edge and weld. Surface composition to a depth of a few microns was determined using SIMS profiling, and direct thickness measurements of surface over-layers on the metal were made using FIB. Marked variations in both the thickness and composition of the over-layers were found when comparing the body/HAZ, weld edge and weld material. Additionally, numerous prismatic inclusions, approximately 5 μm2, were observed at the surface of the weld material. Auger and SIMS analyses indicated these inclusions were nitro-carbides. An increased concentration of these inclusions and other elemental impurities at the margins of the weld and within the HAZ indicated that during welding a segregation of impurities from the molten metal had occurred. The results are discussed in terms of processes considered to be occurring during welding and their implications in regard to corrosion in hydrogen atmospheres.

  2. Auger electron appearance potential spectrum of Ni

    International Nuclear Information System (INIS)

    Electrons are accelerated onto a solid polycrystalline Ni surface. These primary electrons interact with the surface to produce one of two phenomena: x-ray fluorescence, or Auger electron emission. Auger Electron Appearance Potential Spectroscopy (AEAPS) is a process by which the Auger component of the secondary electron flux is analysed to extract qualitative information about the electronic structure of the empty conduction band states. In AEAPS, the threshold behavior of the Auger transitions is examined by taking the first derivative of the secondary electron current with respect to the incident electron energy using the potential modulation technique. Width of the empty band, degree of localization of the conduction band wave functions, overlapping of the 3d band with the 4s, and satellite phenomena are among the important parameters ascertainable by AEAPS. The present AEAPS measurements of L3 levels of Ni are compared with the reported data from Soft X-ray Appear nce Potential Spectroscopy (SXAPS) of Ni. SXAPS is a complimentary process of AEAPS in that it examines the secondary xray fluorescence from the surface in much the same way as AEAPS examines the total electron yield. AEAPS, used alone, or in conjunction with SXAPS, is considered to be a powerful technique for the systematic investgation of series of metals, such as the transition, or lanthanide series

  3. Surface compositions of atomic layer deposited Zn1−xMgxO thin films studied using Auger electron spectroscopy

    International Nuclear Information System (INIS)

    In this paper, the authors present Auger electron spectroscopy (AES) studies of Zn1−xMgxO (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. Zn1−xMgxO 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 Zn1−xMgxO alloys

  4. The determination of carbon, nitrogen and oxygen in TiCsub(x)Nsub(y)Osub(z) with the Auger electron spectroscopy (AES)

    International Nuclear Information System (INIS)

    The possibility of determining the carbon, nitrogen and oxygen contents in TiCsub(x)Nsub(y)Osub(z) with the Auger-electron-spectroscopy (AES) is discussed. As an example the concentration dependence over the cross section of 1 μm thick TiN-layers is presented. (orig.)

  5. Auger spectroscopy of fracture surfaces of ceramics

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Effect of heating on the behaviors of hydrogen in C-TiC films with auger electron spectroscopy and secondary ion mass spectroscopy analyses

    International Nuclear Information System (INIS)

    C-TiC films with a content of 75% TiC were prepared with magnetron sputtering deposition followed by Ar+ ion bombardment. Effect of heating on the behaviors of hydrogen in C-TiC films before and after heating was studied with Auger Electron Spectroscopy and Secondary Ion Mass Spectroscopy (SIMS) analyses. SIMS depth profiles of hydrogen after H+ ion implantation and thermal treatment show different hydrogen concentrations in C-TiC coatings and stainless steel. SIMS measurements show the existence of TiH, TiH2, CH3, CH4, C2H2 bonds in the films after H+ ion irradiation and the changes in the Ti LMM, Ti LMV and C KLL Auger line shape reveal that they have a good hydrogen retention ability after heating up to the temperature 393 K. All the results show that C-TiC coatings can be used as a hydrogen retainer or hydrogen permeable barrier on stainless steel to protect it from hydrogen brittleness

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

    Science.gov (United States)

    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.

  10. Mass and Auger electron spectroscopy studies of the interactions of atomic and molecular chlorine on a plasma reactor wall

    International Nuclear Information System (INIS)

    We have investigated the interactions of Cl and Cl2 with an anodized Al surface in an inductively coupled chlorine plasma. The cylindrical substrate is rapidly rotated within a differentially pumped wall and is exposed to the plasma 35% of the time through a conical skimmer. On the opposite side of the substrate, a second skimmer and differential pumping allows the surface and desorbing products to be analyzed by Auger electron spectroscopy (AES), line-of-sight mass spectrometry (MS), and through pressure rise measurements. In a 600 W Cl2 plasma at 5 mTorr, the surface becomes covered with a layer with the overall stoichiometry of about Al2Si2O10Cl3, with Si being the result of the slow erosion of the quartz discharge tube. The surface layer composition (specifically Cl coverage) does not change as a function of the delay time (1 ms-10 min) between plasma exposure and AES characterization. In contrast to AES measurements, the MS signals from Cl2 desorption, resulting from recombination of Cl atoms, decrease by about a factor of 10 over the 1-38 ms probed by varying the substrate rotation frequency. Substantial adsorption and desorption of Cl2 are also observed with the plasma off. Cl recombination coefficients (γCl) derived from an analysis of the time-dependent MS signals range from 0.01 to 0.1 and increase with increasing Cl-to-Cl2 number density ratio, suggesting a competition for adsorption sites between Cl2 and Cl

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

    International Nuclear Information System (INIS)

    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

  12. Observation of resonant transfer and excitation in O5+ + He collisions through high resolution O0 Auger electron spectroscopy

    International Nuclear Information System (INIS)

    In this paper we present new evidence that (resonant transfer and excitation) RTE is an important mechanism for the production of Be-like doubly excited states in energetic collisions of Li-like O5+ ions incident on He. We have measured the cross sections for the production of Auger electrons from the decay of the (1s2s2p2)3D and the (1s2s2p2)1D states in O4+ in high resolution at O0, as a function of the incident ion energy. We observe a resonant increase in the Auger cross section with a maximum at approx.13 MeV and full-width-at-half-maximum of approx.7 MeV. This feature is seen to sit on a non-resonant NTE background, which populates the same intermediate states through a two step capture and excitation process governed by the electron-nucleus Coulomb interaction. 13 ref., 3 figs

  13. Auger electron spectroscopy study on the stability of the interface between deposited Cu9Al4 intermetallic compound film and Si

    International Nuclear Information System (INIS)

    The interaction of deposited Cu9Al4 intermetallic compound film with a silicon substrate is studied by Auger electron spectroscopy. Although the incorporation of silicon into the Cu9Al4 film with low concentration level is observed, the interface is stable up to the annealing temperature of 700degC without forming aluminum spikes or a copper silicide layer. It is revealed that Cu9Al4 film is a useful material to realize a stable interface when employed as a metallization material for silicon devices. (author)

  14. Auger electron spectroscopy (AES) study of the initial stages of oxidation of the single crystal Be (0001) surface

    International Nuclear Information System (INIS)

    The oxidation of Be(0001), in particular the early stages of the reaction, was tracked dynamically by AES using a computer controlled single pass CMA. The reaction was followed by monitoring the three Auger transitions, Be(KVV), BeO(KVV), and O(KVV) in dN/dE mode. Because the Be(KVV) and the BeO(KVV) signals overlap, a multiple linear regression analysis based on a linear combination of the spectra of clean, cleaved Be and a BeO crystal was done to separate them. Results have been obtained for oxygen partial pressures ranging from 4.7 x 10-7 Pa (3.6 x 10-9 Torr) to 1.3 x 10-4 Pa. Considerable structure is seen in the uptake curves suggesting the occurrence of multiple stages of growth. The oxidation process appears to be linearly dependent on pressure for high pressures. Further conclusions are made difficult due to the strong enhancement of the oxidation by the AES incident electron beam. Finally, at all pressures studied, an excess of oxygen signal compared to that expected from stoichiometric BeO exists in the very early stage of the oxidation

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

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ting; Romero, Danilo; Gomez, Romel D., E-mail: rdgomez@umd.edu [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    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.

  16. Secondary Auger electrons and prostate cancer therapy

    International Nuclear Information System (INIS)

    Complete text of publication follows. Auger emitters emit electrons of relatively low energy, from ∼ 25 KeV to ∼ 500 eV, and therefore are of relatively low range. Thus, an important medical application for Auger emitters emerges as an effective means of controlling cancer due to the restrictive irradiation volume surrounding the emitter and therefore the possibility of a selective attack on cancer cells. There are two ways to perform an experiment with an Auger emitter. The first is to use a radionuclide that emits Auger electrons (Barchytherapy). The second is to stimulate a stable, potential Auger emitter inside the malignant cell using external irradiation. To achieve a therapeutic benefit, one must synthesize tumor selective chemicals. These compounds (porphyrins, phthalocaynines) should have two properties: i) Physically, it must have a metal ion with a large atomic number that will produce a large number of Auger electrons, ii) Chemically, it should be water-soluble and able to penetrate the cell membrane and attach itself to the cell target (e.g. DNA). The chemical properties sem contradictory, however, since these compounds are big molecules and have many side chains, one can build a porphyrin molecule that has on one side a hydrophilic component and on the other side a hydrophobic component. The physical and chemical aspects are discussed and some biological results will be presented

  17. Auger electron transport calculations in biological matter

    International Nuclear Information System (INIS)

    The talk briefly discussed physical, biophysical, and biological aspects of Auger emitters. A summary of radiationless transition data available in published literature and databases were presented. Data were presented for electron capture (EC), internal conversions (IC), binding energies of some commonly used radionuclides 123I, 124I, 125I, and 158Gd. For each of these Auger emitting radionuclides some examples of Monte Carlo calculated electron spectra of individual decays were presented. Because most Auger electrons emitted in the decay of radionuclides are short range low energy electrons below 1 keV, a brief discussion was presented on most recent development of physics models for energy loss of electrons in condensed phase and compared with other models and gas phase data. Accuracy of electron spectra calculated in the decay of electron shower by Auger emitting radionuclides depends on availability of accurate physics data. Currently, there are many gaps in physics data as input data to computer codes in need of new evaluation. In addition, comparison should be made between deterministic and Monte Carlo methods to access the accuracy and sensitivity of data to methods and the chosen parameters. It has long been recognized that Auger electron show a high-LET like characteristics when radionuclide is very closely bound to DNA. As most Auger electrons are short range low energy electrons and mostly absorbed with the DNA duplex when in close vicinity to DNA duplex, we believe the physical and biological dosimetry are best achieved by using Monte Carlo track structure simulations able to simulate tracks of low energy electrons below 1keV and in particular sub 100 eV in condensed phas

  18. Rutherford backscattering and Auger spectroscopy of mercuric iodide detectors

    Energy Technology Data Exchange (ETDEWEB)

    Felter, T.E.; Stulen, R.H. (Sandia National Labs., Livermore, CA (USA)); Schnepple, W.F.; Ortale, C.; Van den Berg, L. (EG and G Energy Measurements, Inc., Goleta, CA (USA). Santa Barbara Operations)

    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 {approx equal} 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. (orig.).

  19. Rutherford backscattering and Auger spectroscopy of mercuric iodide detectors

    Science.gov (United States)

    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.

  20. Rutherford backscattering and Auger spectroscopy of mercuric iodide detectors

    International Nuclear Information System (INIS)

    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. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Investigations of thiosulfate accumulation on 304 stainless steel in neutral solutions by radioactive labeling, electrochemistry, Auger electron and X-ray photoelectron spectroscopy methods

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, A.E.; Kolics, A.; Wieckowski, A. [Univ. of Illinois, Urbana, IL (United States)

    1997-02-01

    Thiosulfate accumulation on 304 stainless steel in near neutral solutions (pH {approximately}5.6) was studied using in situ techniques: electrochemistry and radiochemistry, as well as by Auger electron spectroscopy depth profiling and angle-resolved x-ray photoelectron spectroscopy in ultrahigh vacuum. It was found that thiosulfate accumulation is an irreversible process and occurs over a broad electrode potential range. Thiosulfate surface concentration is very small, below {minus}1.0 V vs. Ag/AgCl reference. In the potential range from {minus}1.0 to 0.50 V the surface concentration increases linearly with potential, reaches a maximum at {minus}0.30 V, and at even more positive potentials, decreases to a slightly lower level. Ultrahigh vacuum spectroscopic measurements indicate that the irreversible surface behavior can be attributed to thiosulfate incorporation into the substrate passive film. The present data obtained with 304 stainless steel are compared to previous results published from this laboratory on thiosulfate adsorption on 316 stainless steel, and the role of molybdenum surface enrichment in the thiosulfate accumulation reversibility is discussed. The effect of chloride on thiosulfate accumulation was also investigated. At high concentration of chloride, thiosulfate is desorbed from the surface due to chloride-induced dissolution of the stainless steel. At very negative potentials, the thiosulfate surface concentration increases upon chloride addition, most probably due to the surface microroughening caused by chloride adsorption.

  3. In situ proton-induced X-ray emission and Auger electron spectroscopy study of titanium and niobium implantation of iron films

    International Nuclear Information System (INIS)

    Implantation of 190 keV titanium and niobium ions into iron films 200 nm thick electron beam deposited onto polished Si(100) substrates has been investigated. During the course of implantation of the iron films, proton-induced X-ray emission was used to measure the instantaneous film thickness and the total retained dose, whereas Auger electron spectroscopy was used to determine the surface concentrations of the implanted species and the reactive elements. Implantations were carried out both under ultrahigh vacuum conditions and with the chamber backfilled with CO to a pressure of 1 X 10-6 Torr. Elemental sputtering yields were measured for iron and the implanted elements as a function of fluence. The results showed that, for titanium implantation, the addition of CO to the target chamber significantly reduced the sputtering yield of the substrate and increased the retained dose that could be achieved. For niobium implantation the addition of CO to the chamber reduced the substrate sputtering yield, but not to the same degree as observed for titanium, and did not alter the total retained dose that could be achieved. (Auth.)

  4. Quantitative depth profiling of nitrogen-implanted titanium by use of Auger electron spectroscopy and subsequent target factor analysis

    International Nuclear Information System (INIS)

    Titanium samples were implanted with N+ and N2+ ions of an energy of 80 keV and an ion dose between 1017 and 1018 atoms cm-2, which led to near-surface nitrogen-containing coatings. Auger depth profiles were taken from these coatings and the gathered data were subjected to target factor analysis. As a main result, three components could be detected and assigned to metallic Ti, TiN and a hitherto unknown Ti/N component, the atomic concentration ratio of which was estimated to be Ti:N ≅ 1:1.15. Thereby, the atomic concentration depth profiles could be calculated, resulting in the stoichiometry of titanium nitride at an implantation dose from 5 x 1017 N+ cm-2 upwards. A relationship between the ion implantation dose and the wear resistance of the coatings could not be corroborated by the measurements. (author)

  5. Application of the Auger and X-ray photoelectron electronic spectroscopies to the study of superficial segregation in the system Pt-Rh

    International Nuclear Information System (INIS)

    The Auger and X-ray photoelectron spectroscopies are applied to the study of the superficial segregation in the system of the binary alloy Pt-Rh. The methodology for the cleaning of the samples, which is essential for the obtainment of reproducible results, has been established. The spectra qualitative analysis allows to identify the element segregated. The application of the Gallon model permits to develop a quantitative study of the phenomenon. (S.M.)

  6. Differential auger spectrometry

    Science.gov (United States)

    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.

  7. Verification of surface polarity of O-face ZnO(0 0 0 1{sup Macron }) by quantitative modeling analysis of Auger electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Su, C.W., E-mail: cwsu@mail.ncyu.edu.tw [Department of Electrophysics, National Chiayi University, 300 Syuefu Rd., Chiayi 60004, Taiwan (China); Huang, M.S.; Tsai, T.H.; Chang, S.C. [Department of Electrophysics, National Chiayi University, 300 Syuefu Rd., Chiayi 60004, Taiwan (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Quantitative Auger intensity ratios to predict macroscopic surface type to Zn-face or O-face can be obtained using hard sphere model and considering electron mean free paths. Black-Right-Pointing-Pointer Calculation of electron signals from 6-layer depth is the best condition in estimating Auger intensity ratios. Black-Right-Pointing-Pointer The ratio deviated from the estimation reference after surface treated by annealing or sputtering is classified to Zn-rich or O-rich surface. Black-Right-Pointing-Pointer A Zn-rich surface may exist on an O-face surface. Black-Right-Pointing-Pointer Surface type of a composite material can be quickly obtained by quantitative analysis of Auger intensity ratio. - Abstract: Is crystalline ZnO(0 0 0 1{sup Macron }) 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{sup Macron })-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.

  8. Utilization of the statistics techniques for the analysis of the XPS (X-ray photoelectron spectroscopy) and Auger electronic spectra's deconvolutions

    International Nuclear Information System (INIS)

    For the analysis of the XPS (X-ray photoelectron spectroscopy) and Auger spectra, it is important to performe the peaks' separation and estimate its intensity. For this purpose, a methodology was implemented, including: a spectrum's filter; b) substraction of the base line (or inelastic background); c) deconvolution (separation of the distribution that integrates the spectrum) and d) error of calculation of the mean estimation, comprising adjustment quality tests. A software (FORTRAN IV plus) that permits to use the methodology proposed from the experimental spectra was implemented. The quality of the methodology was tested with simulated spectra. (Author)

  9. Absolute auger electron spectra obtained by a novel cylindrical mirror analyzer

    International Nuclear Information System (INIS)

    A novel cylindrical mirror analyzer (CMA) has been developed to obtain standard spectra in Auger electron spectroscopy. We obtained Auger electron spectra of gold, nickel, and soot (carbon). For gold, the details of the spectra are shown and the possible Auger transitions are identified for the whole range of energy by subtracting a background of assumed simple polynomial function. The total range spectra of nickel and soot are reported for the primary accelerating voltages ranging 1-5000 V. In other words, the spectra of true secondary electron, Auger electron, loss electrons which excited shell electron and plasmon, and elastically backscattered primary electron are shown. It is found that the carbon (soot) as evacuated always presents clean surface without any ion sputtering treatment and the surface is quite stable. (author)

  10. Electron Spectroscopy for Material Characterization

    OpenAIRE

    Süzer, Şefik

    1998-01-01

    Basic principles of the two electron spectroscopic techniques, the x-ray photoelectron spectroscopy, XPS, and the Auger electron spectroscopy, AES, are given. Their utilization in material characterization are introduced through examples with application of these techniques to various surface related problems.

  11. Investigation of surface layer composition of the rhodium-ruthenium catalysts by means of auger spectroscopy

    International Nuclear Information System (INIS)

    The surface layer composition of skeleton catalysts of the rhodium-ruthenium system by means of Auger-electron spectroscopy and electron spectroscopy for the chemical analysis is investigated. It is shown that apart from rhodium, ruthenium aluminium and silicon there is a certain quantity of chemosorbed oxygen accumulated in case of catalysts conservation over a long period of time. The dependence of filling catalysts by chemosorbed oxygen on the alloy composition has been found

  12. Quantitative comparison between Auger electron spectroscopy and secondary ion mass spectroscopy depth profiles of a double layer structure of AlAs in GaAs using the mixing-roughness-information depth model

    International Nuclear Information System (INIS)

    Application of the so called mixing-roughness-information (MRI) depth model to quantitative reconstruction of the in-depth distribution of the composition is demonstrated by comparing secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES) depth profiles. A GaAs/AlAs reference sample consisting of two layers of AlAs [1 and 36 monolayer (ML)] separated by 44 ML of a GaAs matrix was depth profiled using almost identical sputtering conditions: Ar+ ions of 3 keV impact energy and 52 deg. (SIMS: CAMECA 4f) and 58 deg. (AES: VG Microlab 310F) incidence angle. Both the Al+ intensity of the SIMS profile and the Al (LVV) intensity of the AES profile were quantified by fitting the measured profiles with those calculated with the MRI model, resulting in the same mixing length of 3.0±0.3 nm, similar roughness parameter (1.4-2 nm), and negligible information depth (0.4 nm). Whereas practically no matrix effect was observed for AES as well as for Al+ in the SIMS profile, quantification using dimer (Al2+) and trimer (Al3+) ions shows a marked nonlinearity between concentration and intensity, with the main effect caused by the simple mass action law probability of cluster ion formation

  13. Study of the adsorption of methyl iodide and molecular iodine on clean uranium and uranium dioxide surfaces by means of X-ray photoelectron (XPS) and Auger electron spectroscopy (AES)

    International Nuclear Information System (INIS)

    The adsorption of methyl iodide as well as of molecular iodine on uranium metal and on uranium dioxide has been studied at 250C. Surfaces of the substrates were cleaned and characterized before and after exposure using X-ray photoelectron (XPS) and X-ray and electron induced Auger electron (AES) spectroscopy. Exposures amounted up to 1500 L CH3I on uranium metal, 1000 L CH3I on UO2, 100 L I2 on uranium metal, and 75 L I2 on UO2 (1 L = 1 Langmuir = 10-6 torr x sec). From the measured binding energies, Auger parameters, and intensity ratios for substrate and adsorbate constituents we deduced that for both CH3I and I2 on uranium metal a uranium iodide, UI3, is formed. The adsorption of CH3I on U-metal is in addition accompanied by the formation of a carbide-type carbon, UC. Thus, in both cases a dissociative (adsorption/reaction) process is observed. For adsorption of CH3I on UO2 the experimental findings indicate a dissociative process, too, though the species formed could not be identified. In contrast, I2 adsorption on UO2 appears to have non-dissociative character. Saturation coverages for CH3I were found to be approx.= 2 L on U-metal and approx.= 5 L on UO2, for I2 approx.= 40 L on U-metal and 10-15 L on UO2. Variations in the iodine Auger kinetic energy and in the Auger parameter are interpreted in light of extraatomic relaxation processes. (orig.)

  14. Making use of x-ray optical effects in photoelectron-, Auger electron-, and x-ray emission spectroscopies: Total reflection, standing-wave excitation, and resonant effects

    International Nuclear Information System (INIS)

    We present a general theoretical methodology and related open-access computer program for carrying out the calculation of photoelectron, Auger electron, and x-ray emission intensities in the presence of several x-ray optical effects, including total reflection at grazing incidence, excitation with standing-waves produced by reflection from synthetic multilayers and at core-level resonance conditions, and the use of variable polarization to produce magnetic circular dichroism. Calculations illustrating all of these effects are presented, including in some cases comparisons to experimental results. Sample types include both semi-infinite flat surfaces and arbitrary multilayer configurations, with interdiffusion/roughness at their interfaces. These x-ray optical effects can significantly alter observed photoelectron, Auger, and x-ray intensities, and in fact lead to several generally useful techniques for enhancing surface and buried-layer sensitivity, including layer-resolved densities of states and depth profiles of element-specific magnetization. The computer program used in this study should thus be useful for a broad range of studies in which x-ray optical effects are involved or are to be exploited in next-generation surface and interface studies of nanoscale systems.

  15. Electronic structure of Ti metal and TiO2 powder studied by hard and soft (Cu Kα1 and Al Kα1) X-ray photoelectron and Auger spectroscopy

    International Nuclear Information System (INIS)

    High-energy X-ray photoelectron spectroscopy (XPS) is of particular importance for minimizing the effects of surface contamination by increasing photoelectron escape depths. In this study high-resolution high-energy Cu Kα1 and soft Al Kα1 XPS and Auger electron spectroscopy were used to compare the electronic structure of Ti in TiO2 powder and Ti metal. The Ti 1s in TiO2 XPS line is narrower and more symmetric than in Ti metal. A comparison of the relative intensities of the L23M23M45 and L23M23M23 Auger transitions in Ti metal and TiO2 is consistent with the expected transfer of Ti 3d electrons away from the Ti site in the oxide. The satellites accompanying the Ti 1s XPS line excited by Cu Kα1 X-rays occur at the same energies as the satellites accompanying the Ti 2s and 2p XPS lines excited by Al Kα1 X-rays indicating that they do not depend on the core-level, the experimental resolution or inelastic scattering processes

  16. Rutherford Backsattering and Auger spectroscopy of mercuric iodide detectors

    International Nuclear Information System (INIS)

    The electrical properties of metallic contacts on solid state x-ray detectors can play an important role in determining the overall response and sensitivity of these devices. Rutherford Backscattering (RBS) and Auger electron spectroscopies have been utilized to characterize thin palladium contacts on mercuric iodide (HgI2) detectors. The RBS measurements were performed at room temperature with the metal contact preventing evaporate loss of the HgI2 and reducing contamination to the vacuum chamber. Computer simulations of the RBS results indicate that the interface region of a sample with a palladium contact had approximately the ideal stoichiometry but that the palladium film thickness (350 /angstrom/) was less than expected from the deposition conditions. Auger sputter profiling which removes the metal contact ''cap'' was performed with a rapid transfer system equipped with liquid nitrogen cooling to avoid evaporative loss of the sample and reduce vacuum system contamination. This technique indicated significant penetration of Hg and I into the Pd contact for a variety of samples. In many cases, the penetration extended all the way to the surface. For a 600 /angstrom/ contact, approximately two thirds or 400 /angstrom/ of the contact is part of a ''reaction zone'' in which there is strong intermixing of the palladium, mercury, and iodine. In one case, where copper was tried as an electrode, the ''reaction zone'' extended all the way to the surface, and the device failed as a detector. The relationship of the contact stoichiometry to the deposition process and device performance will be discussed. 5 refs., 4 figs

  17. Rutherford Backsattering and Auger spectroscopy of mercuric iodide detectors

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-01-01

    The electrical properties of metallic contacts on solid state x-ray detectors can play an important role in determining the overall response and sensitivity of these devices. Rutherford Backscattering (RBS) and Auger electron spectroscopies have been utilized to characterize thin palladium contacts on mercuric iodide (HgI/sub 2/) detectors. The RBS measurements were performed at room temperature with the metal contact preventing evaporate loss of the HgI/sub 2/ and reducing contamination to the vacuum chamber. Computer simulations of the RBS results indicate that the interface region of a sample with a palladium contact had approximately the ideal stoichiometry but that the palladium film thickness (350 /angstrom/) was less than expected from the deposition conditions. Auger sputter profiling which removes the metal contact ''cap'' was performed with a rapid transfer system equipped with liquid nitrogen cooling to avoid evaporative loss of the sample and reduce vacuum system contamination. This technique indicated significant penetration of Hg and I into the Pd contact for a variety of samples. In many cases, the penetration extended all the way to the surface. For a 600 /angstrom/ contact, approximately two thirds or 400 /angstrom/ of the contact is part of a ''reaction zone'' in which there is strong intermixing of the palladium, mercury, and iodine. In one case, where copper was tried as an electrode, the ''reaction zone'' extended all the way to the surface, and the device failed as a detector. The relationship of the contact stoichiometry to the deposition process and device performance will be discussed. 5 refs., 4 figs.

  18. Metastable states in NO2+ probed with Auger spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Püttner, R.; Sekushin, V.; Fukuzawa, H.; Uhlíková, T.; Špirko, Vladimír; Asahina, T.; Kuze, N.; Kato, H.; Hoshino, M.; Tanaka, H.; Thomas, T. D.; Kukk, E.; Tamenori, Y.; Kaindl, G.; Ueda, K.

    2011-01-01

    Roč. 13, č. 41 (2011), s. 18436-18446. ISSN 1463-9076 Grant ostatní: GA ČR(CZ) GP203/09/P306; GA AV ČR(CZ) IAA400400504; GA MŠk(CZ) LC06071 Institutional research plan: CEZ:AV0Z40550506 Keywords : NO2 +metastable states * Auger spectroscopy * vibrational energies Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.573, year: 2011

  19. Composition profiles of several contaminated and cleaned surfaces of gold thick films on copper plates by Auger electron and secondary ion mass spectroscopies

    International Nuclear Information System (INIS)

    Preparation and evaluation of a clean Au film are investigated. Development of a preparation method for obtaining clean surface on a copper shell in the JFT-2a (DIVA) TOKAMAK toroidal vacuum chamber is the aim of the present work. Au films prepared by ion plating and vacuum evaporation have been analysed by a cylindrical mirror Auger electron analyser in combination with a quadrupole mass spectrometer during 2 keV Xe ion bombardment from a sputter ion gun over the whole range of thickness of several microns. Contaminants are found to segregate on the top surface and at the interface. To expose a clean Au surface by the ion bombardment, surface layers within 1000 A had to be removed from the surfaces contaminated by touching with either a naked hand or a nylon glove or covered by a small amount of Ti. Mutual diffusions across the interfaces are also analyzed as a function of the substrate temperature. A Nb sandwich layer inhibites effectively the mutual diffusion. (auth.)

  20. Electron microscopy and auger spectroscopy study of the wetting of the grain boundaries in the systems Mo-Pb, Mo-Sn, Mo-Ni and Ni-Pb

    International Nuclear Information System (INIS)

    Understanding the mechanism of the intergranular penetration of a liquid phase into a metallic solid is an important problem. The structural and chemical characterization of nano-metric films at grain boundaries is now possible by using high resolution electron microscopy associated with X-ray micro-analysis, electron energy loss spectroscopy and Auger spectroscopy. In order to study this problem, two different classes of model materials were selected according to their crystallographic structure: a bcc metal (molybdenum) and an fcc one (nickel). The wetting element was either lead or tin or nickel. In a first approach, the metallic matrix was polycrystalline. The conditions in which the liquid phase penetrates into the grain boundaries were studied by using special preparation and observation techniques. In particular, the use of a Focused Ion Beam microscope (FIB) allowed the preparation of thin foils located very precisely inside the matrix as well as multi-scale observations. These specimens were further observed in electron microscopy with a very high resolution. (authors)

  1. On the Equivalent Dose for Auger Electron Emitters

    OpenAIRE

    Howell, Roger W.; Narra, Venkat R.; Sastry, Kandula S. R.; Rao, Dandamudi V.

    1993-01-01

    Radionuclides that emit Auger electrons are widely used in nuclear medicine (e.g., 99mTc, 123I, 201T1) and biomedical research (e.g., 51Cr, 125I), and they are present in the environment (e.g., 40K, 55Fe). Depending on the subcellular distribution of the radionuclide, the biological effects caused by tissue-incorporated Auger emitters can be as severe as those from high-LET α particles. However, the recently adopted recommendations of the International Commission on Radiological Protection (I...

  2. Measurement of the background in Auger-photoemission coincidence spectra (APECS) associated with inelastic or multi-electron valence band photoemission processes

    OpenAIRE

    Satyal, S.; Joglekar, P. V.; Shastry, K.; Kalaskar, S.; Dong, Q.; Hulbert, S. L.; Bartynksi, R. A.; Weiss, A. H.

    2014-01-01

    Auger Photoelectron Coincidence Spectroscopy (APECS), in which the Auger spectra is measured in coincidence with the core level photoelectron, is capable of pulling difficult to observe low energy Auger peaks out of a large background due mostly to inelastically scattered valence band (VB) photoelectrons. However the APECS method alone cannot eliminate the background due to valence band photoemission processes in which the initial photon energy is shared by two or more electrons and one of th...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kupliauskiene, A. [Institute of Theoretical Physics and Astronomy of Vilnius University, A. Gostauto 12, LT-01108 Vilnius (Lithuania)], E-mail: akupl@itpa.lt; Tutlys, V. [Institute of Theoretical Physics and Astronomy of Vilnius University, A. Gostauto 12, LT-01108 Vilnius (Lithuania)

    2009-01-15

    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.

  4. Chemical-state imaging of Li using scanning Auger electron microscopy

    International Nuclear Information System (INIS)

    Highlights: •Scanning Auger electron microscopy is used to image chemical states of Li. •The combined use of AES and EELS signals for the elemental mapping is powerful. •Distribution corresponding to metallic and oxidized states of Li can be imaged. -- Abstract: The demand for measurement tools to detect Li with high spatial resolution and precise chemical sensitivity is increasing with the spread of lithium-ion batteries (LIBs) for use in a wide range of applications. In this work, scanning Auger electron microscopy (SAM) is used to image chemical states of a partially oxidized Li surface on the basis of the Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS) data obtained during an oxidation process of a metal Li. We show that distribution of metallic and oxidized states of Li is clearly imaged by mapping the intensity of the corresponding AES and EELS peaks. Furthermore, a tiny difference in the extent of oxidation can be distinguished by comparing the elemental map of an AES peak with that of an EELS peak owing to the different behaviors of those signals to the chemical states of Li

  5. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    International Nuclear Information System (INIS)

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to ΔE/E∼10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION registered ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to ΔE/E 2,3VV-transition with PAES. Thus, within this thesis two objectives were achieved: Firstly, the PAES spectrometer was renewed and improved by at least one order of magnitude with respect to the signal to noise ratio, the measurement time and the energy resolution. Secondly, several measurements have been carried out, demonstrating the high performance of the spectrometer. Amongst them are first dynamic PAES measurements and a high resolution measurement of the CuM2,3VV

  6. Some results of Auger spectroscopy and emission spectroscopy applied to impregnated cathodes

    International Nuclear Information System (INIS)

    A study of impregnated cathodes using combined Auger spectroscopy and emission microscopy shows that a realistic pressures regions of thick-film coverage emit more strongly than monolayer regions. The presence of sulphur and phosphorus on the surface of dispenser cathodes has been correlated with poor emission. These contaminants may be removed by heating cathodes in oxygen, a process which increases substantially the emission available from poor cathodes. (orig.)

  7. Auger electron spectroscopic study of CO2 adsorption on Zircaloy-4 surfaces

    International Nuclear Information System (INIS)

    We investigate the adsorption of CO2 onto Zircaloy-4 (Zry-4) surfaces at 150, 300 and 600 K using Auger electron spectroscopy (AES). Following CO2 adsorption at 150 K the graphitic form of carbon is detected, whereas upon chemisorption at 300 and 600 K we detect the carbidic phase. As the adsorption temperature is increased, the carbon Auger signal increases, whereas the oxygen signal decreases. Adsorption at all three temperatures results in a shift of the Zr Auger features, indicating surface oxidation. The effect of adsorbed CO2 on the Zr(MVV) and Zr(MNV) transitions depends on adsorption temperature and is less pronounced at higher temperatures. On the other hand, changes in the Zr(MNN) feature are similar for all three adsorption temperatures. The changes in the Zr Auger peak shapes and positions are attributed to oxygen from dissociated CO2, with the differences observed at various temperatures indicative of the diffusion of oxygen into the subsurface region

  8. Ramsey method for Auger-electron interference induced by an attosecond twin pulse

    OpenAIRE

    Buth, Christian; Schafer, Kenneth J.

    2010-01-01

    We examine the archetype of an interference experiment for Auger electrons: two electron wave packets are launched by inner-shell ionizing a krypton atom using two attosecond light pulses with a variable time delay. This setting is an attosecond realization of the Ramsey method of separated oscillatory fields. Interference of the two ejected Auger-electron wave packets is predicted, indicating that the coherence between the two pulses is passed to the Auger electrons. For the detection of the...

  9. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Jakob

    2010-04-03

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to {delta}E/E{approx}10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION {sup registered} ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to {delta}E/E < 1. The exceptional surface sensitivity and elemental selectivity of PAES was demonstrated in measurements of Pd and Fe, both coated with Cu layers of varying thickness. PAES showed that with 0.96 monolayer of Cu on Fe, more than 55% of the detected Auger electrons stem from Cu. In the case of the Cu coated Pd sample 0.96 monolayer of Cu resulted in a Cu Auger fraction of more than 30% with PAES and less than 5% with electron induced Auger spectroscopy

  10. Auger electron, electron energy loss and secondary electron emission spectroscopic studies on the oxidation of zirconium at high temperatures and room temperature

    International Nuclear Information System (INIS)

    Auger electron (AES), electron energy loss (EELS) and secondary electron emission spectroscopy (SES) have been used to investigate the surface oxidation of zirconium at room temperature and high temperatures, 773-973 K, under low oxygen pressures 1.3 x 10-5 - 1.3 x 10-3 Pa. The kinetic energies of the Auger and the secondary electrons and the electron losses by single electron excitations are explained by the electronic structure in the core and the valence states of the metal and the oxide of zirconium. The energy loss by the collective excitation of plasmon is also observed in the EELS measurement for the metal and the oxide surface. The increase in the relative peak-to-peak height of the oxygen Auger transition and of the zirconium Auger transition by oxidation at high temperature does not depend simply on the oxygen exposure represented by the product of oxygen pressure and exposure time, i.e. exposure in Langmuir, because of the dynamic competition between surface processes and the diffusion process of oxygen into the bulk. The rate of oxide growth is found to be parabolic at high temperature (773 K) and at 1.3 x 10-5 Pa. (Author)

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

    Science.gov (United States)

    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.

  12. Digital Electronics for the Pierre Auger Observatory AMIGA Muon Counters

    CERN Document Server

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

    2013-01-01

    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.

  13. Three-dimensional atomic-arrangement reconstruction from an Auger-electron hologram

    International Nuclear Information System (INIS)

    Current methods for reconstructing three-dimensional atomic arrangements from photoelectron holograms require data sets recorded using multiple incident photon energies. These techniques are thus difficult to apply to Auger-electron holography, since the kinetic energy of the Auger electron is element specific and independent of excitation energy. We propose a scattering pattern extraction algorithm using a maximum-entropy method for reconstructing the three-dimensional atomic arrangement from a single-energy Auger-electron hologram. The algorithm provides a clear atomic image by taking into account the scattering of the electron by nearby atoms and the non-s-wave nature of the Auger electron. We have applied the algorithm to an Auger-electron hologram of Cu(001) recorded at SPring-8's soft x-ray synchrotron radiation beamline BL25SU and succeeded in determining the positions of 102 atoms of the Cu fcc structure

  14. Observation of resonance recombination lines in electron excited Auger spectra of Gd

    International Nuclear Information System (INIS)

    Combined measurements of electron excited Nsub(4,5) Auger spectra and photoelectron emission on clean and oxidized Gd lead to a distinction between Auger lines originating from 4d → continuum and 4d → 4f resonance excitations. Several Auger structures are identified as due to the direct recombination of 4d94f8 states with the 4f and valence electrons. The shape of the most prominent Auger line for oxidized Gd agrees perfectly with the Fano profile of the 4f photoemission intensity. (orig.)

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

    Science.gov (United States)

    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. Ne, Ar, Fe, and Cu Auger-electron production at National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Energetic K and L Auger electrons produced by focussed, filtered, broad-band synchrotron radiation have been measured at the x-ray ring of the National Synchrotron Light Source (NSLS). The x-ray beam was used to study inner-shell photoionization of Ne and Ar gas and Fe and Cu solid film targets. The Auger electrons were analyzed by means of a semi-hemispherical electrostatic electron spectrometer at the energy resolution of ∼ 3 %. The electrons were detected at both 90 degree and 0 degree with respect to the photon beam direction. Broad distributions of the inner-shell photoelectrons were also observed, reflecting the incoming photon flux distribution. The Fe and Cu K Auger electron spectra were found to be very similar to the Ar K Auger electron spectra. This was expected, since deep inner-shell Auger processes are not affected by the outer valence electrons. Above 3 keV in electron energy, there have been few previous Auger electron measurements. 2 figs., 13 refs

  17. Attosecond streaking of shake-up and Auger electrons in xenon

    Directory of Open Access Journals (Sweden)

    Drescher M.

    2013-03-01

    Full Text Available We present first results of simultaneous attosecond streaking measurements of shake-up electrons and Auger electrons emitted from xenon. We extract relative photo-emission delays for electrons emitted from the 4d, 5s and 5p subshell, as well as for the 5p−25d correlation satellite (shake-up electrons.

  18. Attosecond streaking of shake-up and Auger electrons in xenon

    Science.gov (United States)

    Verhoef, A. J.; Mitrofanov, A.; Krikunova, M.; Kabachnik, N. M.; Drescher, M.; Baltuska, A.

    2013-03-01

    We present first results of simultaneous attosecond streaking measurements of shake-up electrons and Auger electrons emitted from xenon. We extract relative photo-emission delays for electrons emitted from the 4d, 5s and 5p subshell, as well as for the 5p-25d correlation satellite (shake-up electrons).

  19. Digital Electronics for the Pierre Auger Observatory AMIGA Muon Counters

    OpenAIRE

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

    2013-01-01

    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 slo...

  20. Core-valence coupling in the Ru 4p photoexcitation/Auger decay process: Auger-photoelectron coincidence spectroscopy study

    International Nuclear Information System (INIS)

    The N23VV Auger spectrum of Ru has been measured in coincidence with 4p1/2 and with 4p3/2 photoelectrons. Unlike other metals that exhibit bandlike Auger decays, we find that the two Auger spectra are not shifted by the difference in core level binding energies. A consistent description of these transitions and the core level line shape requires consideration of the relativistic multiplet splitting in the intermediate core hole state and two-valence-hole Auger final state. The results suggest that the large linewidth of the 4p levels is primarily due to multiplet splitting, and that an N2(N3N45)N45N45 super-Coster-Kronig transition is only a minor decay channel. (c) 2000 The American Physical Society

  1. Photoelectron Spectroscopy of Ions: Study of the Auger Decay of the 4d→nf (n=4,5) Resonances in Xe^{5+} Ion.

    Science.gov (United States)

    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

  2. Metrological electron spectroscopy:AES%计量学的电子谱:俄歇电子能谱

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Electron spectroscopy is now very popular particularly in surface analysis.Many manufacturers make their sophisticated machines,in which Auger electron spectroscopy(AES)and X-ray photoelectron spectroscopy (XPS)have been widely distributed and commonly used.Although,the electron spectroscopy is not in the category of metrology,i.e.,the SI(system international).

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

    International Nuclear Information System (INIS)

    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. (author)

  4. Radiotoxicity induced by auger electron emitters in human osteosarcoma cell line using comet assay

    International Nuclear Information System (INIS)

    The comet assay (single cell gel electrophoresis assay) was used to evaluate the radiotoxicity of Auger electron emitters in the human osteosarcoma cell line (HOS-8603). After internal exposure to 67Ga-EDTMP, the sarcoma cell has been injured severely. The comet length was longer along with the increase of dose, the appearance of comet tail was different from that with respect to the 60Co γ-ray irradiation. DNA damage of cell was mainly due to the radiation effect of Auger electrons. The 67Ga may be a therapeutic radionuclide with good prospect for tumor treatment and palliation of bone pain induced by metastasis

  5. Chirped Auger electron emission due to field-assisted post-collision interaction

    Directory of Open Access Journals (Sweden)

    Bonitz M.

    2013-03-01

    Full Text Available We have investigated the Auger decay in the temporal domain by applying a terahertz streaking light field. Xenon and krypton atoms were studied by implementing the free-electron laser in Hamburg (FLASH as well as a source of high-order harmonic radiation combined with terahertz pulses from an optical rectification source. The observed linewidth asymmetries in the streaked spectra suggest a chirped Auger electron emission which is understood in terms of field-assisted post-collision interaction. The experimentally obtained results agree well with model calculations.

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

    Science.gov (United States)

    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.

  7. Surface sensitivity effects with local probe scanning Auger-scanning electron microscopy

    NARCIS (Netherlands)

    Van Agterveld, DTL; Palasantzas, G; De Hosson, JTM; Bentley, J; Allen, C; Dahmen, U; Petrov,

    2001-01-01

    Ultra-high-vacuum segregation studies on in-situ fractured Cu-Sb alloys were performed in terms of nanometer scale scanning Auger/Electron microscopy. S contamination leads to the formation Of Cu2S precipitates which, upon removal due to fracture, expose pits with morphology that depends on the prec

  8. Effects of the electron–hole pair in Auger and X-ray photoemission spectroscopy from surfaces of Fe–Si

    Energy Technology Data Exchange (ETDEWEB)

    Gervasoni, J.L. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, Universidad Nacional de Cuyo, R8402AGP S. C. de Bariloche, Rio Negro (Argentina); Jenko, M.; Poniku, B.; Belič, I. [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia); Juan, A. [Departamento de Física, Universidad Nacional del Sur, Bahia Blanca (Argentina)

    2015-07-01

    In this work, we investigate in detail the effects due to the interaction between an electron and a stationary positive ion (or atomic hole) in the neighborhood of a surface of Fe–Si, having a strong plasmon peak in their electron energy loss spectra, when it is excited with synchrotron radiation. We take into account the effects due to the sudden creation of an electron and the residual holes, one in the case of X-ray photoemission spectroscopy (XPS) and two in the case of Auger electron spectroscopy (AES). We use a semi classical dielectric formulation for the photoelectron trajectory, and we estimated the parameter r{sub s}, the radius of the sphere occupied by one electron in the solid, which is critical in order to define the electron density of the alloy. With the cited formulation, we have obtained a detailed behavior of the different contributions of the collective excitations in both processes.

  9. Calculations of energies and absolute intensities of Auger electrons and X-rays arising from electron capture decay

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chun-Mei; WU Zhen-Dong; HUANG Xiao-Long

    2005-01-01

    Calculations of energies and absolute intensities of Auger electron and X-ray arising from electron capture are introduced briefly. The calculation codes and main process are also presented. The application is also given by taking 55Fe ε decay as an example.

  10. Site-selective resonant Auger spectroscopy of iso-dichloroethylene at the carbon K-edge

    International Nuclear Information System (INIS)

    Highlights: ► We provide detailed results on electron decay following core excitations to two carbon atoms to the LUMO in different chemical environments to the LUMO in CH2=CCl2. ► The experimental results are compared with high-quality theoretical calculations. ► We report calculated valence spectra in the ground-state, C (CH2) and C (CCl2) core-excited states. -- Abstract: This study focuses on the two C1s-to-LUMO (lowest unoccupied molecular orbital) excitations of the iso-dichloroethylene (H2C=CCl2) and the subsequent Auger decay. We investigate the effect of the two different carbon core excitations on the population of the cation produced after electronic relaxation. The resonant Auger spectra are interpreted by comparison to the valence shells photoionization spectrum and with the help of theoretical calculations. Several consequences of the core-hole localization on the electronic decay are observed. In particular, the resonant excitation of the C1s(CH2) to the LUMO leads to a large intensity increase in the region of the first satellite state, whereas no dramatic changes are observed for the C1s(CCl2) excitation.

  11. Fragmentation of CF3Br induced by fluroine is core excitation: Energy resolved auger electron multiple-ion coincidence measurements

    International Nuclear Information System (INIS)

    Fragmentation processes in CF3Br near the F K edge were investigated using synchrotron radiation and Energy Resolved Auger Electron Multiple Ion Coincidence (ERAEMICO). Time-of flight mass spectra were collected in coincidence with either selected F 1s Auger or resonant-Auger electrons which were energy analyzed with a hemispherical detector. In addition, a more inclusive mass spectrum was taken near the F 1s ionization potential in coincidence with low energy electrons. Preliminary spectra the Br2+ ion intensity is negligible and the relative CF+ abundance is higher. These differences confirm the notion that the electronic state prior to bond breakage governs the resulting fragmentation pattern

  12. Secondary electron emission due to Auger de-excitation of metastable nitrogen molecules at metallic surfaces

    OpenAIRE

    Marbach, J.; Bronold, F. X.; Fehske, H.

    2011-01-01

    With an eye on plasma walls we investigate, within an effective model for the two active electrons involved in the process, secondary electron emission due to Auger de-excitation of metastable nitrogen $N_2(^3\\sigma^+_u)$ molecules at metallic surfaces. Modelling bound and unbound molecular states by a LCAO approach and a two-center Coulomb wave, respectively, and the metallic states by the eigenfunctions of a step potential we employ Keldysh Green's functions to calculate the secondary elect...

  13. Studies of the AgM5N45N4.5 spectrum of disordered Ag0.5Pd0.5 alloy by Auger photoelectron coincidence spectroscopy (APECS)

    International Nuclear Information System (INIS)

    Full text: The Auger electron emission process from solids is very complex, with a range of intrinsic processes producing intensity in final spectra. These processes can include the basic Auger process, initial- and final-states, shake-up/off and Coster-Kronig (CK) processes. Auger Photoelectron Coincidence Spectroscopy (APECS) is a technique to detect the Auger electron only when the 'initial' photoelectron also is detected. By counting those Auger electrons that arrive in coincidence with a photoelectron of certain binding energy, the initial state is uniquely determined, thus controlling the magnitude of various satellites of the Auger spectrum. AxPd1-x is a disordered alloy. XPS spectra indicated that the FWHM of Ag 3d5/2 increases from 0.56 eV in pure Ag to 0.77 eV in Ag0.5Pd0.5. The disorder broadening of the Ag 3d core line in AgPd is due to the spread of local potentials in the atomic cores arising from the effects of charge transfer. In this study, an effect of disorder broadening of the core level photoelectron line on the Ag MVV Auger spectra in random substituted Ag0.5Pd0.5 alloy has been investigated by APECS. Data were collected for the AgM5V45V45 Auger line in coincidence with Ag 3d photoelectron lines. It is shown that the broadening of the AgM5V45V45 line is directly associated with the presence of disorder broadening of the Ag 3d5/2 photoelectron line

  14. Study of very thin oxide layers by conversion and Auger electrons

    International Nuclear Information System (INIS)

    Oxidic layers as thin as 20-30 A on α-Fe and stainless steel are studied by 57Fe-DCEMS with K-conversion electrons and ICEMS. No indication of a vanishing f-factor could be found. Moessbauer spectra, recorded by use of LMM-Auger electrons (AEMS) and by electrons emitted with energies below 15 eV (LEEMS), contain information on the surface layer as well as on the bulk material, showing that part of these electrons are due to secondary effects and the high escape depths of K-conversion electrons. (orig.)

  15. Contribution of scanning Auger microscopy to electron beam damage study

    International Nuclear Information System (INIS)

    Electron bombardment can produce surface modifications of the analysed sample. The electron beam effects on solid surfaces which have been discussed in the published literature can be classified into the following four categories: (1) heating and its consequent effects, (2) charge accumulation in insulators and its consequent effects, (3) electron stimulated adsorption (ESA), and (4) electron stimulated desorption and/or decomposition (ESD). In order to understand the physico-chemical processes which take place under electron irradiation in an Al-O system, we have carried out experiments in which, effects, such as heating, charging and gas contamination, were absent. Our results point out the role of an enhanced surface diffusion of oxygen during electron bombardment of an Al (111) sample. The importance of this phenomenon and the contribution of near-elastic scattering of the primary electrons (5 keV) to the increase of the oxidation degree observed on Al (111) are discussed, compared to the generally studied effects

  16. Investigations on the low voltage cathodoluminescence stability and surface chemical behaviour using Auger and X-ray photoelectron spectroscopy on LiSrBO3:Sm3+ phosphor

    International Nuclear Information System (INIS)

    Highlights: → Stable orange-red cathodoluminescence observed from LiSrBO3:Sm3+ phosphor. → In situ Auger electron spectroscopy, while monitoring the CL output reduction, reveals surface concentration modification of Li, Sr, B and O atoms. → X-ray photoelectron spectroscopy confirms the formation of SrO2 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 LiSrBO3:Sm3+ phosphors were synthesized through the solid-state reaction method. Under UV radiation (221 nm) and low-voltage electron beam (2 keV, 12 mA/cm2) excitation, the Sm3+ doped LiSrBO3 phosphor shows emission corresponding to the characteristic 4G5/2-6H7/2 transitions of Sm3+ 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 LiSrBO3:Sm3+ 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 LiSrBO3:Sm3+ 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 SrO2 was identified by XPS on the phosphor surface after it received an electron dose of 300 C/cm2 together with the increase in the concentrations of chemical species containing the B-C-O bonding. The new surface chemical species formed during electron beam bombardment are possibly responsible for the stability of the CL in the LiSrBO3:Sm3+ phosphor.

  17. Nanodosimetry of 125I – Auger electrons – Experiment and modeling

    International Nuclear Information System (INIS)

    The experiment with 125I-Auger electrons, interacting with gaseous nitrogen with size equivalent to segment of DNA in mass per unit area scale, are described. The discrete ionization cluster-size distributions have been obtained. The shapes of which are definitely determined by the size of the interaction volumes. The volume sizes studied in the present work are comparable with a segment of DNA and of nucleosome. The experiments have been carried out with the set up, called Jet Counter, and are the first cluster-size distributions as yet measured for an Auger-electron emitter like 125I. The experimental results have been compared with those obtained by Monte Carlo simulation. The results for 125I have been compared with calculated cluster size distribution for 131I.

  18. Multilevel-targeted polymer Auger electron emitter delivery system for cancer therapy

    Czech Academy of Sciences Publication Activity Database

    Hrubý, Martin; Sedláček, Ondřej; Studenovský, Martin; Kučka, Jan; Větvička, D.

    Nantes: Laboratoire Subatech, 2013. s. 55. [Workshop on Innovative Personalized Radioimmunotherapy - WIPR 2013 "Radiopharmaceuticals: from research to industry". 09.07.2013-12.07.2013, Nantes] R&D Projects: GA ČR GA13-08336S; GA MPO FR-TI4/625 Grant ostatní: AV ČR(CZ) M200501201 Institutional support: RVO:61389013 Keywords : Auger electron emitter * drug delivery * intercalator Subject RIV: CA - Inorganic Chemistry

  19. 123I: Calculation of the Auger electron spectrum and assessment of the strand breakage efficiency

    International Nuclear Information System (INIS)

    Auger cascades induced by electron capture in 123I have been simulated by the Monte Carlo technique with special emphasis on the determination of the electron kinetic energies. By using an approach which considers the individual electron population of all electronic shells before and after a transition, errors in the electron energy normally introduced when applying the so-called (Z+1)-approximation are avoided. Thus, the energy of the electrons released in transitions between higher shells were found to be about half the value mentioned in the literature. An average total number of 7.6 electrons (6.4 Auger-, and 1.2 shake-off electrons) has been determined to be emitted per decay, a number which is considerably lower than those reported in similar studies. The efficiency of strand break induction has been assessed to be 0.4 DSB and 1.1 additional SSB per decay of DNA bound 123I. A comparison with the corresponding DSB values of 125I reveals that 125I is 2.5 times more effective than 123I. This is about the same ratio as that determined by Makrigiorgos on the basis of cell killing experiments

  20. Distribution of strand breaks produced by Auger electrons in decay of iodine 125 in triplex DNA

    International Nuclear Information System (INIS)

    In this study we investigate the possibility of using Auger electrons as a probing agent for the study of structures of nucleic acids. To this end, we present the distribution of breaks produced in strands of a DNA duplex and a triplex-forming oligonucleotide (TFO) carrying Auger emitting radionuclide 125I. The method of calculation includes use of a molecular model of plasmid DNA duplex with bound TFO carrying a labelled 125I at position C5 of a single deoxycytosine residue, a source of Auger spectra, Monte Carlo electron track structure and the ensuing chemistry codes, to simulate the distribution of breaks produced in both strands of a plasmid DNA. Frequencies of fragment length distributions were obtained for the TFO, the purine and the pyrimidine strands. The frequency of breaks in the purine strand showed good correlation with the published experimental results, while that for the pyrimidine strand is lower by a factor of 3. It is concluded that the true structure of triplex DNA may not be purely of B-form

  1. Distribution of strand breaks produced by Auger electrons in decay of iodine 125 in triplex DNA

    Energy Technology Data Exchange (ETDEWEB)

    Nikjoo, H.; Panyutin, I.G.; Terrissol, M.; Vrigneaud, J.M.; Laughton, C.A. [MRC Radiation and Genome Stability Unit, Harwell (United Kingdom)

    2000-11-01

    In this study we investigate the possibility of using Auger electrons as a probing agent for the study of structures of nucleic acids. To this end, we present the distribution of breaks produced in strands of a DNA duplex and a triplex-forming oligonucleotide (TFO) carrying Auger emitting radionuclide {sup 125}I. The method of calculation includes use of a molecular model of plasmid DNA duplex with bound TFO carrying a labelled {sup 125}I at position C5 of a single deoxycytosine residue, a source of Auger spectra, Monte Carlo electron track structure and the ensuing chemistry codes, to simulate the distribution of breaks produced in both strands of a plasmid DNA. Frequencies of fragment length distributions were obtained for the TFO, the purine and the pyrimidine strands. The frequency of breaks in the purine strand showed good correlation with the published experimental results, while that for the pyrimidine strand is lower by a factor of 3. It is concluded that the true structure of triplex DNA may not be purely of B-form.

  2. Temperature dependence of ion-induced Auger electron emission from (111) silicon: Pt. 1

    International Nuclear Information System (INIS)

    Measurements have been made of both the secondary electron emission coefficient, γ, and SiL23 Auger yield, ρA for a (111)Si target bombarded by high fluence of noble gas ions. For Si irradiated at room temperature at doses more than 1017 ions per cm2, a monotonically increasing variation of γ and ρA with incidence angle i was observed. For Si irradiated at a temperature more than a critical value, γ(i) and ρA(i) curves exhibited minima superimposed on the monotonic variation when the ion beam penetrated the crystal along low index directions. In the range 20-6500C, the Auger yield temperature dependence showed a sharp variation around a critical value depending on the ion mass for a given incident energy. These results are linked to an amorphous-crystalline phase transition. (author)

  3. Temperature dependence of ion-induced Auger electron emission from (111) silicon: Pt. 1; Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Benazeth, C.; Hecquet, P.; Mayoral, C.; Benazeth, N. (Toulouse-3 Univ., 31 (France))

    1989-06-01

    Measurements have been made of both the secondary electron emission coefficient, gamma, and SiL{sub 23} Auger yield, rho{sub A} for a (111)Si target bombarded by high fluence of noble gas ions. For Si irradiated at room temperature at doses more than 10{sup 17} ions per cm{sup 2}, a monotonically increasing variation of gamma and rho{sub A} with incidence angle i was observed. For Si irradiated at a temperature more than a critical value, gamma(i) and rho{sub A}(i) curves exhibited minima superimposed on the monotonic variation when the ion beam penetrated the crystal along low index directions. In the range 20-650{sup 0}C, the Auger yield temperature dependence showed a sharp variation around a critical value depending on the ion mass for a given incident energy. These results are linked to an amorphous-crystalline phase transition. (author).

  4. Satellite X-ray lines and KLL Auger electrons from fluorine compounds

    International Nuclear Information System (INIS)

    Fluorine K X-rays are excited by irradiation of solid samples (LiF, NaF, KF, RbF, CsF, AgF; BeF2, MgF2, CaF2, CrF2, FeF2, CoF2, NiF2, CuF2, SnF2, ZnF2, PbF2, BaF2) with α-particles. Optimal conditions for the observation of Kαsub(3,4) satellites from thick samples are obtained with 2 MeV4He+ particles from a Van de Graaff generator. X-rays are analysed with a Bragg spectrometer equipped with a flat crystal of TIAP, the resolution is 1.2 eV for Fluorine K X-rays. Auger electrons are excited by irradiation of same samples with Al Kαsub(1,2) X-rays; electrons from the main KLL Auger line are detected with a resolution of about 1 eV. The observations made on these compounds are in accordance with previous data on a few samples as reported by Deconninck et al. (1978). Important variations in shape and amplitude are observed in Kαsub(3,4) X-ray and KLL Auger spectra. The relative amplitude of the Kαsub(3,4) peak is maximum in ionic compound and the peak width is narrower, this amplitude decreases with increasing covalency and the presence of energy band is observed by the energy spreading of the peaks (X-ray and Auger). The competition between different decay modes is investigated in an attempt to interpretate the relative amplitude of the satellite peaks. (author)

  5. Features of atomic images reconstructed from photoelectron, Auger electron, and internal detector electron holography using SPEA-MEM

    International Nuclear Information System (INIS)

    Highlights: • We develop a 3D atomic image reconstruction algorithm for photoelectron, Auger electron, and internal detector holography. • We examine the shapes of the atomic images reconstructed by using a developed kernel function. • We examine refraction effect at surface, limitation effect of the hologram data, energy resolution effect, and angular resolution effect. • These discussions indicate the experimental requirements to obtain the clear 3D atomic image. - Abstract: Three-dimensional atomic images can be reconstructed from photoelectron, Auger electron, and internal detector electron holograms using a scattering pattern extraction algorithm using the maximum entropy method (SPEA-MEM) that utilizes an integral transform. An integral kernel function for the integral transform is the key to clear atomic image reconstruction. We composed the kernel function using a scattering pattern function and estimated its ability. Image distortion caused by multiple scattering was also evaluated. Four types of Auger electron wave functions were investigated, and the effect of these wave function types was estimated. In addition, we addressed refraction at the surface, the effects of data limitation, and energy and angular resolutions

  6. Features of atomic images reconstructed from photoelectron, Auger electron, and internal detector electron holography using SPEA-MEM

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Tomohiro, E-mail: matusita@spring8.or.jp [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan); Matsui, Fumihiko [Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192 (Japan)

    2014-08-15

    Highlights: • We develop a 3D atomic image reconstruction algorithm for photoelectron, Auger electron, and internal detector holography. • We examine the shapes of the atomic images reconstructed by using a developed kernel function. • We examine refraction effect at surface, limitation effect of the hologram data, energy resolution effect, and angular resolution effect. • These discussions indicate the experimental requirements to obtain the clear 3D atomic image. - Abstract: Three-dimensional atomic images can be reconstructed from photoelectron, Auger electron, and internal detector electron holograms using a scattering pattern extraction algorithm using the maximum entropy method (SPEA-MEM) that utilizes an integral transform. An integral kernel function for the integral transform is the key to clear atomic image reconstruction. We composed the kernel function using a scattering pattern function and estimated its ability. Image distortion caused by multiple scattering was also evaluated. Four types of Auger electron wave functions were investigated, and the effect of these wave function types was estimated. In addition, we addressed refraction at the surface, the effects of data limitation, and energy and angular resolutions.

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

    Science.gov (United States)

    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.

  8. Accelerator based production of auger-electron-emitting isotopes for radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thisgaard, H.

    2008-08-15

    In this research project the focus has been on the identification and production of new, unconventional Auger-electron-emitting isotopes for targeted radionuclide therapy of cancer. Based on 1st principles dosimetry calculations on the subcellular level, the Auger-emitter 119Sb has been identified as a potent candidate for therapy. The corresponding imaging analogue 117Sb has been shown from planar scintigraphy and single-photon emission computed tomography (SPECT) to be suitable for SPECT-based dosimetry of a future Sb-labeled radiopharmaceutical. The production method of these radioisotopes has been developed using a low-energy cyclotron via the nuclear reactions 119Sn(p,n)119Sb and 117Sn(p,n)117Sb including measurements of the excitation function for the former reaction. Moreover, a new high-yield radiochemical separation method has been developed to allow the subsequent separation of the produced 119Sb from the enriched 119Sn target material with high radionuclidic- and chemical purity. A method that also allows efficient recovery of the 119Sn for recycling. To demonstrate the ability of producing therapeutic quantities of 119Sb and other radioisotopes for therapy with a low-energy cyclotron, two new 'High Power' cyclotron targets were developed in this study. The target development was primarily based on theoretical thermal modeling calculations using finite-element-analysis software. With these targets, I have shown that it will be possible to produce several tens of GBq of therapeutics isotopes (e.g. 119Sb or 64Cu) using the PETtrace cyclotron commonly found at the larger PET-centers in the hospitals. Finally, research in a new method to measure the radiotoxicity of Auger-emitters invitro using cellular microinjection has been carried out. The purpose of this method is to be able to experimentally evaluate and compare the potency of the new and unconventional Auger-emitters (e.g. 119Sb). However, due to experimental complications, the development

  9. Accelerator based production of auger-electron-emitting isotopes for radionuclide therapy

    International Nuclear Information System (INIS)

    In this research project the focus has been on the identification and production of new, unconventional Auger-electron-emitting isotopes for targeted radionuclide therapy of cancer. Based on 1st principles dosimetry calculations on the subcellular level, the Auger-emitter 119Sb has been identified as a potent candidate for therapy. The corresponding imaging analogue 117Sb has been shown from planar scintigraphy and single-photon emission computed tomography (SPECT) to be suitable for SPECT-based dosimetry of a future Sb-labeled radiopharmaceutical. The production method of these radioisotopes has been developed using a low-energy cyclotron via the nuclear reactions 119Sn(p,n)119Sb and 117Sn(p,n)117Sb including measurements of the excitation function for the former reaction. Moreover, a new high-yield radiochemical separation method has been developed to allow the subsequent separation of the produced 119Sb from the enriched 119Sn target material with high radionuclidic- and chemical purity. A method that also allows efficient recovery of the 119Sn for recycling. To demonstrate the ability of producing therapeutic quantities of 119Sb and other radioisotopes for therapy with a low-energy cyclotron, two new 'High Power' cyclotron targets were developed in this study. The target development was primarily based on theoretical thermal modeling calculations using finite-element-analysis software. With these targets, I have shown that it will be possible to produce several tens of GBq of therapeutics isotopes (e.g. 119Sb or 64Cu) using the PETtrace cyclotron commonly found at the larger PET-centers in the hospitals. Finally, research in a new method to measure the radiotoxicity of Auger-emitters invitro using cellular microinjection has been carried out. The purpose of this method is to be able to experimentally evaluate and compare the potency of the new and unconventional Auger-emitters (e.g. 119Sb). However, due to experimental complications, the development of this

  10. Radiotoxicity induced by Auger electron emitters in human osteosarcoma cell line using comet assay

    Institute of Scientific and Technical Information of China (English)

    XU Yu-Jie; LI Qing-Nuan; ZHU Ran; ZHU Ben-Xing; ZHANG Yong-Ping; ZHANG Xiao-Dong; FAN Wo; HONG Cheng-Jiao; LI Wen-Xin

    2003-01-01

    The comet assay (single cell gel electrophoresis assay) was used to evaluate the radiotoxicity of Augerelectron emitters in the human osteosarcoma cell line (HOS-8603). After internal exposure to 67Ga-EDTMP, the sar-coma cell has been injured severely. The comet length was longer along with the increase of dose, the appearance ofcomet tail was different from that with respect to the 60Co γ-ray irradiation. DNA damage of cell was mainly due tothe radiation effect of Auger electrons. The 67Ga may be a therapeutic radionuclide with good prospect for tumortreatment and palliation of bone pain induced by metastasis.

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

    Science.gov (United States)

    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.

  12. Auger Electron Therapy: Photoelectric Absorption at the L-edge for Cancer Radiotherapy

    International Nuclear Information System (INIS)

    In this in vivo study, the emission of Auger electrons from platinum atoms, physiologically-targeted to tumor cell DNA, were used to enhance the radiation dose to a murine mammary carcinoma in a radiotherapeutic technique, Auger Electron Therapy (AET). AET requires the simultaneous presence of two agents, a) a radiation source whose energies are suitable for inducing a photoelectric effect in a high Z atom, and b) a molecule that transports the high Z atom in or near tumor cell DNA. Unlike most studies where the K absorption edge is used to stimulate Auger emission after the induction of a photoelectric effect in a high Z atom, this work exploited the L edge of platinum. Soft γ-rays from palladium-103 brachytherapy seeds (20 keV), implanted directly in the radio-resistant KHJJ breast tumor (TCD50 = 54Gy) borne subcutaneously on the thigh, generated a photoelectric effect at the L edge of platinum atoms (13.8 keV) transported to tumor cell DNA by the porphyrin, PtTMPyP(4) after an i.p. injection of 40 mg/kg. The photoelectric event resulted in tumor growth delay by a factor of 5 for mice receiving the AET treatment [PtTMPyP(4) and 103Pd] compared to those with the implanted 103Pd seeds alone. The outcome of the experiment suggests the potential application of AET in the radiotherapy clinic where brachytherapy is deemed the treatment of choice. This work was supported by the Israel Ministry of Trade and Industry and by Rotem Industries

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

    Science.gov (United States)

    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

  14. An auger spectroscopy investigation of the surfaces of austenitic stainless steels

    International Nuclear Information System (INIS)

    Full text.Various studies have been shown that during annealing of stainless steels, various impurities and alloying elements segregate to the surface of the material, leading to a considerable effect on the properties. The object of this work is to study the segregation of elements such as chromium, phosphorous, sulphur and nitrogen to the surface of an austenitic stainless steel made by UGINE (France) and BCR (Algeria). The investigation is carried out by in-situ annealing inside the ultra-vacuum chamber of an Auger electron spectrometer (AES). The specimens are initially homogenised by an anneal at 1050 celsius degree inside evacuated silica capsules. They are then introduced inside the vacuum chamber of the AES where they are first of all activated, at room temperature, by ionic bombardment and then heat treated at various temperatures ranging from 600 celsius degree to 900 celsius degree. the results are obtained in the form of AES spectra recorded in the differential mode. It is found that the surface of the material undergoes alterations, some of which are temporary and others durable. These alterations are : co-segregation of nitrogen and chromium, segregation of sulphur and competition between nitrogen and sulphur and between phosphorous and sulphur. The driving force of segregation is in the following order : S>P>N

  15. Sputtering measurements on CTR materials using Auger electron spectroscopy

    International Nuclear Information System (INIS)

    The sputter yield of Nb, W, C, and Ag by Ar+ in the energy range from 0.5 to 1.5 keV was measured. In addition, the sputter yield for W, C and Ag by H+ at 11.0 keV has been determined. With the exception of carbon, the data are in general agreement with earlier work. For carbon, some discrepancies between the present work and earlier studies are found. It is suggested that major factors contributing to these discrepancies are structural and/or chemical in nature

  16. Improvements upon the continuum wavefunctions of Auger electrons by use of the least-squares variational method

    International Nuclear Information System (INIS)

    A variational least-squares technique is developed to obtain an iterative improvements upon the wavefunctions of Auger electrons emitted by the ion Ar2+. The core potentials seen by the Auger electrons are evaluated on the basis of the Hartree-Fock orbitals delivered by the conventional Hartree-Fock programs. In order to illustrate our technique, the transition rates of the Auger electrons emitted from Ar corresponding to different configurations, namely 1s → 3p 3p, 1s → 3s 3s, 1s → 2s 2s, 1s → 2p 2p, 1s → 2s 3s and 1s → 2p 3p are calculated. (author)

  17. Methods for Determining Metal Uptake in Cellular DNA for Auger Electron Therapy

    International Nuclear Information System (INIS)

    Stable indium-labeled tetra(4-N-methylpyridyl)porphyrin [InTMPyP(4)] was evaluated as a carrier of a high Z atom, indium (In), into tumor cell DNA for its subsequent activation by radiation in a proposed radiotherapeutic technique, Auger Electron Therapy (AET). Porphyrins with metals can bind to DNA and are useful vehicles for transporting the indium to the DNA of the tumor. AET combines the use of a metalloporphyrin with a stable high Z atom, such as indium, and photons emitted from radioactive brachytherapy seeds, such as iodine-125, to increase the radiation dose in the DNA of the tumor by generating a photoelectric effect in the K absorption edge of the indium (In) atom. This results in the emission of cascading Auger electrons that act as high LET radiation and thus impart significant non-reparable damage to the tumor compared to the radiation alone. The K absorption edge of In is 27.9 keV and the average photon energy of the iodine-125 seeds is ∼ 28 keV

  18. Modelling of radiation risk induced by radon and sources of Auger electrons

    International Nuclear Information System (INIS)

    This thesis follows the national and worldwide radon research and application Auger radionuclides in nuclear medicine. Results of this thesis can be summarised into several points: (1) For the prediction of cancer risk following the exposure, it is also necessary to consider the mean cycle time of target cells. From our analyses it can be concluded that the mean cycle time of target cells should exceed 100 days. (2) The value of excess relative risk is for smokers ERR/WLM = (2.4-4.1)x10-3 WLM-1 and that of the nonsmokers ERR/WLM=(4.2-10.7)x10-3 WLM-1, considering the underground medium. Excess relative risk for the nonsmokers ERR/(Bq m-3) = (1.0-3.5) Bq-1 m3 and for smokers ERR/(Bq m-3) = (0.3-1.2) 10-3 Bq-1 m3 is supposed in dwellings. (3) Microdosimetric models are very helpful and suitable for prediction of the radon risk for underground conditions, as well as for indoor radon risk evaluation and they are also able to take into account the influence of the smoking habit. (4) The spatial distribution of energy deposition events and their magnitude is an essential input to evaluate the effects of radiation on biological systems. Therefore, for the calculation of deposited energy from the DNA incorporated Auger emitters, it is necessary at the DNA level to employ the MC calculation. In an effort to save computer time and memory it is possible to use the fitted function for monoenergetic electrons for estimation of at least relative radiotoxicity. The value of energy deposited in a small volume (sphere of diameter 2 nm) can be considered as the first estimation of an Auger emitter's radiotoxicity. (author)

  19. Electron spectroscopy with fast heavy ions

    International Nuclear Information System (INIS)

    Since about 1970 the spectroscopy of Auger-electrons and characteristic x-rays following energetic ion-atom collisions has received a great deal of attention. An increasing number of accelerators, capable of providing a large number of projectile ion species over a wide range of projectile energies, became available for studying ion-atom collision phenomena. Many charged particles from protons up to heavy ions like uranium can be accelerated to energies ranging over six orders of magnitude. This allows us to study systematically a great variety of effects accompanied by dynamic excitation processes of the atomic shells in either the projectile- or target-atoms. The studies yield fundamental information regarding the excitation mechanism (e.g., Coulomb and quasi-molecular excitation) and allow sensitive tests of atomic structure theories. This information in turn is valuable to other fields in physics like plasma-, astro-, or solid-state (surface) physics. It is a characteristic feature of fast heavy-ion accelerators that they can produce highly stripped ion species which have in turn the capability to highly ionize neutral target atoms or molecules in a single collision. The ionization process, mainly due to the strong electrical fields that are involved, allows us to study few-electron atoms with high atomic numbers Z. High resolution spectroscopy performed with these atoms allows a particularly good test of relativistic and QED effects. The probability of producing these few electron systems is determined by the charge state and the velocity of the projectile ions. In this contribution the possibilities of using electron spectroscopy as a tool to investigate fast ion-atom collisions is discussed and demonstrated with a few examples. 30 references

  20. Electron spectroscopy of dilute nitrides

    International Nuclear Information System (INIS)

    The application of electron spectroscopies in dilute nitride semiconductor research for both chemical analysis and the determination of electronic and lattice vibrational properties is described. X-ray photoelectron spectroscopy of the nitrogen bonding configurations in dilute InNxSb1-x and InNxAs1-x alloys is presented. High resolution electron-energy-loss spectroscopy (HREELS) of the plasmon excitations in InNxSb1-x is shown to provide information on the electronic properties of the material, before and after annealing. HREELS is also used to investigate the GaN-like phonon modes in GaNxAs1-x alloys

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

    Science.gov (United States)

    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.

  2. Characteristic X-ray radiation and Auger electrons from resonant coherently excited highly charged ions under channeling

    OpenAIRE

    Balashov, V.V.; Sokolik, A.; Stysin, A.

    2008-01-01

    Density-matrix approach to treat resonant coherent excitation of swift ions in oriented crystals is applied for unified theoretical description of charge state distribution of relativistic resonant coherently excited ions, their characteristic X-ray radiation and, as a new aspect, Auger electron production from doubly excited states.

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

    International Nuclear Information System (INIS)

    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 by125I 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 of125I 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Rezaee, Mohammad, E-mail: Mohammad.Rezaee@USherbrooke.ca; Hunting, Darel J.; Sanche, Léon [Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4 (Canada)

    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

  5. Influence of host matrices on krypton electron binding energies and KLL Auger transition energies

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh., E-mail: inoyatov@jinr.ru [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Institute of Applied Physics, National University, Tashkent, Republic of Uzbekistan (Uzbekistan); Perevoshchikov, L.L. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Kovalík, A. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Filosofov, D.V.; Yushkevich, Yu.V. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Ryšavý, M. [Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Lee, B.Q.; Kibédi, T.; Stuchbery, A.E. [Department of Nuclear Physics, RSPE, The Australian National University, Canberra, ACT 0200 (Australia); Zhdanov, V.S. [Nuclear Physics Institute, Almaty (Kazakhstan)

    2014-12-15

    Highlights: • The K, L{sub 1–3}, M{sub 1–3} electron binding energies in Kr in the Pt bulk determined. • The K, L{sub 1–3}, M{sub 1–3} electron binding energies in Kr in an evaporated Rb layer obtained. • The krypton K, L{sub 1–3}, M{sub 1} atomic level widths determined for the both host matrices. • The Kr KL{sub 2}L{sub 3}({sup 1}D{sub 2}) Auger transition energies measured for the both host matrices. • The KL{sub 2}L{sub 3}({sup 1}D{sub 2}) energy difference between Rb and Kr in the Pt host measured. • Dirac–Fock calculations of the Kr KLL Auger transitions performed. - Abstract: The low-energy electron spectra emitted in the radioactive decay of the {sup 83}Rb and {sup 83}Sr isotopes were measured with a combined electrostatic electron spectrometer. Radioactive sources used were prepared by ion implantation of {sup 83}Sr into a high purity polycrystalline platinum foil at 30 keV and by vacuum-evaporation deposition of {sup 83}Rb on the same type of foil. From the measured conversion electron spectra, the electron binding energies (referenced to the Fermi level) for the K, L{sub 1}, L{sub 2}, L{sub 3}, M{sub 1}, M{sub 2}, and M{sub 3} shell/subshells of krypton in the platinum host were determined to be 14316.4(12), 1914.3(9), 1720.3(9), 1667.6(9), 281.5(9), 209.6(13), and 201.2(15) eV, respectively, and those for the evaporated layer were observed to be lower by 0.7(1) eV. For both host matrices, values of 2.3(2), 4.6(2), 1.7(2), 1.3(2), and 3.2(3) eV were obtained for the krypton K, L{sub 1}, L{sub 2}, L{sub 3}, and M{sub 1} natural atomic level widths, respectively. The absolute energies of 10838.5(9) and 10839.5(10) eV were measured for the KL{sub 2}L{sub 3}({sup 1}D{sub 2}) Auger transition in krypton implanted in Pt and generated in the evaporated rubidium layer, respectively. A value of 601.0(8) eV was measured for the energy difference of the KL{sub 2}L{sub 3}({sup 1}D{sub 2}) transitions in Rb and Kr in the Pt host

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

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, C.S. (California Univ., Davis, CA (United States) Lawrence Berkeley Lab., CA (United States))

    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.

  7. The influence from low energy x-rays and Auger electrons on 4πβ-γ coincidence measurements of electron-capture-decaying nuclides

    International Nuclear Information System (INIS)

    The influence of low energy x-rays and Auger electrons emitted by electron capture nuclides on 4πβ-γ coincidence measurements is investigated. Under the assumption that these radiations are not detected, correction terms are developed for a number of nuclides that are in common use. (author)

  8. Influence from low energy x-rays and Auger electrons on 4. pi beta. -. gamma. coincidence measurements of electron-capture-decaying nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Funck, E.; Larsen, A.N. (Physikalisch-Technische Bundesanstalt, Braunschweig (Germany, F.R.). Abt. Atomphysik; Commission of the European Communities, Geel (Belgium). Central Bureau for Nuclear Measurements)

    1983-03-01

    The influence of low energy x-rays and Auger electrons emitted by electron capture nuclides on 4..pi beta..-..gamma.. coincidence measurements is investigated. Under the assumption that these radiations are not detected, correction terms are developed for a number of nuclides that are in common use.

  9. New trigger algorithm of the Auger fluorescence telescopes and validation of their single electron resolution

    International Nuclear Information System (INIS)

    The Pierre Auger Observatory analyses air shower events of ultra high energy cosmic rays. For the first time the two detector techniques to measure Cherenkov and fluorescence light have been combined to detect primary particle with energies >1019eV. The raw data rate, as measured by the telescope's electronics, is in the order of 9 Gigabyte per second. A multi level trigger system, which reduces the data systematically in several levels and complexities without rejecting important shower events, is necessary. The different trigger levels are realised in hardware as well as in software. A new ansatz for the first software trigger and its functionality is developed and discussed. The trigger is based on the so far not used information of the readout electronics. The resulting trigger level is more efficient and rejects sheet lightning better compared with present trigger level. Thus, the trigger rate to the next trigger level is decreased and the DAQ system is released. Different calibration methods, which are made regularly, are essential for an experiment. The results of different calibration methods have to be consistent to each other. The single electron resolution of the photomultiplier tubes play an important role in this context. The single electron resolution is a geometry and material dependent factor and up to now only known from Monte Carlo simulations. The experimental validation through direct measurement and the importance of the single electron resolution are discussed. The measurement was possible with small modifications of the configuration. The result of the single electron resolution is within its error in good agreement with the one known from Monte Carlo simulations. The low statistical error of 4% shows a low manufacturing tolerance, so that we can assume the resolution to be constant for the type of photomultiplier tubes used. (orig.)

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

    International Nuclear Information System (INIS)

    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 (γH2AX assay) and clonogenic survival were evaluated after exposure to 111In-DTPA-hEGF, an Auger electron-emitting radiopharmaceutical, or IR. The intracellular distribution of 111In-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 γH2AX foci per cell was greater in MDA-MB-468 and 231-H2N cells after IR (0.5 Gy) plus SAHA (1 μM) compared with IR alone (16 ± 0.6 and 14 ± 0.3 vs. 12 ± 0.4 and 11 ± 0.2, respectively). More γH2AX foci were observed in MDA-MB-468 and 231-H2N cells exposed to 111In-DTPA-hEGF (6 MBq/μg) plus SAHA vs. 111In-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 111In-DTPA-hEGF. Clonogenic survival was reduced in MDA-MB-468 and 231-H2N cells after IR (6 Gy) plus SAHA (1 μM) vs. IR alone (0.6% ± 0.01 and 0.3% ± 0.2 vs. 5.8% ± 0.2 and 2% ± 0.1, respectively) and after 111In-DTPA-hEGF plus SAHA compared to 111In-DTPA-hEGF alone (21% ± 0.4% and 19% ± 4.6 vs. 33% ± 2.3 and 32% ± 3.7). SAHA did not affect 111In-DTPA-hEGF nuclear localization. Hypertonic treatment resulted in fewer γH2AX foci per cell after IR and 111In-DTPA-hEGF compared to controls but did not significantly alter clonogenic survival

  11. X-ray absorption and resonant Auger spectroscopy of O2 in the vicinity of the O 1s→σ* resonance: Experiment and theory

    International Nuclear Information System (INIS)

    We report on an experimental and theoretical investigation of x-ray absorption and resonant Auger electron spectra of gas phase O2 recorded in the vicinity of the O 1s→σ* excitation region. Our investigation shows that core excitation takes place in a region with multiple crossings of potential energy curves of the excited states. We find a complete breakdown of the diabatic picture for this part of the x-ray absorption spectrum, which allows us to assign an hitherto unexplained fine structure in this spectral region. The experimental Auger data reveal an extended vibrational progression, for the outermost singly ionized X 2Πg final state, which exhibits strong changes in spectral shape within a short range of photon energy detuning (0 eV>Ω>-0.7 eV). To explain the experimental resonant Auger electron spectra, we use a mixed adiabatic/diabatic picture selecting crossing points according to the strength of the electronic coupling. Reasonable agreement is found between experiment and theory even though the nonadiabatic couplings are neglected. The resonant Auger electron scattering, which is essentially due to decay from dissociative core-excited states, is accompanied by strong lifetime-vibrational and intermediate electronic state interferences as well as an interference with the direct photoionization channel. The overall agreement between the experimental Auger spectra and the calculated spectra supports the mixed diabatic/adiabatic picture

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

    Science.gov (United States)

    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 (nanodosimetry. Instead, stopping cross section, which describes the probability of energy deposition in a target molecule can be an appropriate nanodosimetric

  13. Atomic Physics with Accelerators: Projectile Electron Spectroscopy (APAPES)

    International Nuclear Information System (INIS)

    The new research initiative APAPES (http://apapes.physics.uoc.gr/) has already established a new experimental station with a beam line dedicated for atomic collisions physics research, at the 5 MV TANDEM accelerator of the National Research Centre ''Demokritos'' in Athens, Greece. A complete zero-degree Auger projectile spectroscopy (ZAPS) apparatus has been put together to perform high resolution studies of electrons emitted in ion-atom collisions. A single stage hemispherical spectrometer with a 2-dimensional Position Sensitive Detector (PSD) combined with a doubly-differentially pumped gas target will be used to perform a systematic isoelectronic investigation of K-Auger spectra emitted from collisions of preexcited and ground state He-like ions with gas targets using novel techniques. Our intention is to provide a more thorough understanding of cascade feeding of the 1s2s2p 4P metastable states produced by electron capture in collisions of He-like ions with gas targets and further elucidate their role in the non-statistical production of excited three-electron 1s2s2p states by electron capture, recently a field of conflicting interpretations awaiting further resolution. At the moment, the apparatus is being completed and the spectrometer will soon be fully operational. Here we present the project progress and the recent high resolution spectrum obtained in collisions of 12 MeV C4+ on a Neon gas target

  14. Strand breaks in plasmid DNA following positional changes of Auger-electron-emitting radionuclides

    International Nuclear Information System (INIS)

    The purpose of our studies is to elucidate the kinetics of DNA strand breaks caused by low-energy Auger electron emitters in close proximity to DNA. Previously we have studied the DNA break yields in plasmids after the decay of indium-111 bound to DNA or free in solution. In this work, we compare the DNA break yields in supercoiled DNA of iodine-125 decaying close to DNA following DNA intercalation, minor-groove binding, or surface binding, and at a distance form DNA. Supercoiled DNA, stored at 4 C to accumulate radiation dose from the decay of 125I, was then resolved by gel electrophoresis into supercoiled, nicked circular, and linear forms, representing undamaged DNA, single-strand breaks, and double-strand breaks respectively. DNA-intercalated or groove-bound 125I is more effective than surface-bound radionuclide or 125I free in solution. The hydroxyl radical scavenger DMSO protects against damage by 125I free in solution but has minimal effect on damage by groove-bound 125I. (orig.)

  15. Interactions of ion with solids. Applications of Auger and secondary ion spectroscopies to studying samples made to undergo heating cycles and hydrogen plasma treatment

    International Nuclear Information System (INIS)

    Present investigations result from wall-related effects found in research on TOKAMAK type plasma devices and controlled thermonuclear fusion. In these machines, the vacuum vessel walls undergo thermal heating cycles and bombardment with energetic particles of hydrogen or deuterium. Experiments on samples of stainless NS22S, molybdenum, inconel X750, platinium, graphite and boron carbide, have been investigated from analogy with actual Tokamak structures and devices to come (JET) in addition to conventional plasma diagnostic. An analysis apparatus has been constructed which incorporates Auger electron spectroscopy, secondary ion mass spectroscopy with incident ions or neutrals and thermal desorption analysis of samples representative of Tokamak machine materials. Experiments were performed in the following conditions: sample temperature from 20 deg C to 800 deg C, ion dose from 1015 to 1018 ions/cm2, ion energy or neutral energy from 3keV to 6keV. The identity and surface concentration of species like oxygen, carbon, nitrogen and sulfur on the surfaces investigated as well as the desorb surface species wich can contaminate the plasma were thus correlated as functions of thermal heating cycles and irradiations

  16. Electronic imaging and high spatial resolution slow electron spectroscopy

    International Nuclear Information System (INIS)

    Scanning electron microscopy and scanning Auger are now commonly used techniques. They are extended here to the complete electron energy distribution. It is shown that pictures can be obtained with electron energy loss peaks or with true secondary electron peaks of very low energy. These pictures are performed with very low primary electron energies (Esub(p) approximately 250 eV) and a fairly good spatial resolution. A very wide field of application of these techniques is now open. In the next future, work function and adsorbed hydrogen micromapping will be obtained

  17. Study of grain boundary segregation using the Auger electron emission technique. Annual Technical Progress Report January 1, 1979-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Stein, D. F.; Heldt, L. A.; Funkenbusch, A. W.

    1980-01-01

    The influence of grain boundary chemical composition on hydrogen embrittlement was investigated. Auger electron spectroscopy was employed to determine the grain boundary compositions of nickel-copper alloys containing various concentrations of phosphorus and subjected to various thermal treatments. Phosphorus segregates to grain boundaries during slow cooling, accompanied by reduced concentrations of grain boundary copper. Tensile tests were conducted in air and following cathodic charging with hydrogen. All samples tested in air exhibited a completely ductile fracture; ductility was insensitive to grain boundary composition. Fractures of hydrogen-charged samples were brittle and intergranular; elongation to fracture increased significantly with increasing concentration of grain boundary phosphorus. The influence of phosphorus segregation on embrittlement by hydrogen or by mercury (reported previously) is analyzed in terms of additive and interactive mechanisms. A mechanism based on reduced embrittler concentration at the site of bond rupture due to improved atomic packing is proposed and found to be consistent with the experimental results of this and other investigations.

  18. Development of DNA-based radiopharmaceuticals carrying Auger-electron emitters for anti-gene radiotherapy

    International Nuclear Information System (INIS)

    Targeting of radiation damage to specific DNA sequences is the essence of antigene radiotherapy. This technique also provides a tool to study molecular mechanisms of DNA repair on a defined, single radio damaged site. It was achieved such sequence-specific radio damage by combining the highly localized DNA damage produced by the decay of Auger-electron-emitters such as 125I with the sequence-specific action of triplex-forming oligonucleotides (TFO). TFO complementary to polypurine-polypyrimidine regions of human genes were synthesized and labeled with 125I-dCTP by the primer extension method. 125I-TFO were delivered into cells with several delivery systems. In addition, human enzymes capable of supporting DNA single-strand-break repair were isolated and assessed for their role in the repair of this lesion. Also, the mutagenicity and repairability of 125I-TFO-induced double strand breaks (DSB) were assessed by repair of plasmid possessing a site-specific DSB lesion. Using plasmids containing target polypurine-polypyrimidine tracts, it was obtained the fine structure of sequence-specific DNA breaks produced by decay of 125I with single-nucleotide resolution. It was showed that the designed 125I-TFO in nanomolar concentrations could bind to and introduce double-strand breaks into the target sequences in situ, i.e., within isolated nuclei and intact digitonin-permeabilized cells. It was also showed 125I-TFO-induced DSB to be highly mutagenic lesions resulting in a mutation frequency of nearly 80%, with deletions comprising the majority of mutations. The results obtained demonstrate the ability of 125I-TFO to target specific sequences in their natural environment - within eukaryotic nucleus. Repair of 125I-TFO-induced DNA damage should typically result in mutagenic gene inactivation

  19. Development of DNA-based radiopharmaceuticals carrying Auger-electron emitters for anti-gene radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Panyutin, I.G.; Winters, T.A.; Feinendegen, L.E.; Neumann, R.D. [National Institutes of Health, Bethesda, MD (United States). Dept. of Nuclear Medicine

    2000-09-01

    Targeting of radiation damage to specific DNA sequences is the essence of antigen radiotherapy. This technique also provides a tool to study molecular mechanisms of DNA repair on a defined, single radio damaged site. It was achieved such sequence-specific radio damage by combining the highly localized DNA damage produced by the decay of Auger-electron-emitters such as {sup 125}I with the sequence-specific action of triplex-forming oligonucleotides (TFO). TFO complementary to polypurine-polypyrimidine regions of human genes were synthesized and labeled with {sup 125}I-dCTP by the primer extension method. {sup 125}I-TFO were delivered into cells with several delivery systems. In addition, human enzymes capable of supporting DNA single-strand-break repair were isolated and assessed for their role in the repair of this lesion. Also, the mutagenicity and repairability of {sup 125}I-TFO-induced double strand breaks (DSB) were assessed by repair of plasmid possessing a site-specific DSB lesion. Using plasmids containing target polypurine-polypyrimidine tracts, it was obtained the fine structure of sequence-specific DNA breaks produced by decay of {sup 125}I with single-nucleotide resolution. It was showed that the designed {sup 125}I-TFO in nanomolar concentrations could bind to and introduce double-strand breaks into the target sequences in situ, i.e., within isolated nuclei and intact digitonin-permeabilized cells. It was also showed {sup 125}I-TFO-induced DSB to be highly mutagenic lesions resulting in a mutation frequency of nearly 80%, with deletions comprising the majority of mutations. The results obtained demonstrate the ability of {sup 125}I-TFO to target specific sequences in their natural environment - within eukaryotic nucleus. Repair of {sup 125}I-TFO-induced DNA damage should typically result in mutagenic gene inactivation.

  20. Ballistic-electron-emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kaenel, H. von; Klemenc, M.; Meyer, T. [Eidgenoessische Technische Hochschule, Zurich (Switzerland). Lab. fuer Festkoerperphysik

    2001-04-01

    Ballistic electron-emission spectroscopy (BEES) and microscopy (BEEM) have been carried out on epitaxial metal/semiconductor interfaces and on epitaxial nanostructures in UHV and at low temperatures. We describe how the band structure of the metal may lead to pronounced focusing of the hot carrier beam injected by the scanning tunneling microscope (STM) tip, thereby greatly enhancing the spatial resolution, such that spectroscopy at buried point defects becomes possible. The strain fields of Ge quantum dots buried underneath an epitaxial silicide film on a Si(100) substrate are found to induce a characteristic clustering of linear defects at the metal/semiconductor interface. The Schottky barrier height lowering associated with these defects allows for an easy identification of buried dots, despite the many mechanisms leading to contrast in BEEM images. (orig.)

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

    Science.gov (United States)

    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.

  2. A combined Auger-ESCA spectrometer for materials characterization

    International Nuclear Information System (INIS)

    Combining a Auger spectrometer with an ESCA spectrometer offers special advantages for materials characterization. Auger spectrum allows a very high sensitivity to be obtained due to a rather strong electronic excitation that allows also the presence of small particulates of foreign substance monolayers at the surface to be displayed. So the Auger procedure is suitable for surface cleanliness verification. The photoelectron (ESCA) spectroscopy ensures a high resolution that allows precise measurements of the chemical changes and search on bands structures. Auger and ESCA measurements are directly compared. Measurements are effected on the same sample and practically at the same time without perturbing the ultra high vacuum. On the way, a direct comparison of both method sensitivity is made possible. The procedure makes also possible the surface cleaning using an ion gun incorporated inside the apparatus, by separating a thin film from the others and simultaneously analyzing the profile

  3. Experimental KLM plus KLN Auger spectrum of Cu

    Czech Academy of Sciences Publication Activity Database

    Inoyatov, A. K.; Perevoshchikov, L. L.; Zhdanov, V. S.; Filosofov, D. V.; Kovalík, Alojz

    2013-01-01

    Roč. 18, AUG (2013), s. 23-26. ISSN 0368-2048 R&D Projects: GA ČR(CZ) GAP203/12/1896 Institutional support: RVO:61389005 Keywords : electron spectroscopy * Auger spectra * KLM transitions * transitions energy * Cu-65 * Zn-65 Subject RIV: BG - Nuclear, Atomic and Molecular Physics , Colliders Impact factor: 1.552, year: 2013

  4. Electronic Doppler effect in resonant Auger decay of CO molecules upon excitation near a shake-up Π resonance

    International Nuclear Information System (INIS)

    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 Π 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 |1sC-11π-1π*2> with a strong dissociative character, and the Doppler splitting of the atomic peak has been reproduced by the simulation

  5. Proceedings of the 5. seminar on electron spetroscopy of socialist countries

    International Nuclear Information System (INIS)

    Instrumental, experimental, and theoretical aspects of electron spectroscopy as well as their applications to solve problems arising in surface physics and surface chemistry have been discussed. 94 synopses on photoelectron spectroscopy (XPS and UPS), Auger electron spectroscopy, electron energy loss spectroscopy, appearance potential spectroscopy, low-energy electron diffraction, reflection of high-energy electron diffraction, and secondary ion mass spectroscopy are included

  6. Electron spectroscopy and molecular structure

    International Nuclear Information System (INIS)

    Electron spectroscopy can now be applied to solids, liquids and gases. Some fields of research require ultrahigh vacuum conditions, in particular those directly concerned with surface phenomena on the monolayer level. Liquids have just recently been subject to studies and several improvements and extensions of this technique can be done. Much advance has lately been achieved in the case of gases, where the pressure range presently is 10-5-1 torr. Signal-to-background ratios for core lines can be approximately 1000:1 and the resolution has been increased to the extent that vibrational fine structures of 1s levels in some small molecules have been observed. These improvements are based on the monochromatization of the exciting AlKα radiation. Under such conditions the background is furthermore so much reduced that shake-up structures are more generally accessible for closer studies. ESCA shifts are also much easier to resolve and to measure with higher precision, around 0.02 eV. The photoionization dynamics including atomic and molecular relaxations has been investigated, both experimentally and theoretically. In the valence electron region improvements in energy resolution and in the application of the intensity model based on the MO-LCAO approximation greatly facilitate the assignments of the valence orbitals. Accumulation of empirical evidences gathered from series of similar chemical species and also better methods of calculation, both ab initio and semiempirical, have gradually resulted in a much better understanding of the molecular orbital description. The experience of the latest ESCA instrument with monochromatization has motivated an attempt to design an optimized apparatus according to the general principles of this prototype. A considerable gain in intensity can be made at an improved resolution set by the inherent diffraction pattern of the focussing spherical quartz crystals. (author)

  7. Resonant Auger decay of Ar 2p3/2-14s and 2p3/2-14p states excited by electron impact

    International Nuclear Information System (INIS)

    Auger spectra of resonantly excited 2p3/2-14s and 2p3/2-14p states in argon were measured by (e,2e) technique. The 99.2-eV scattered electrons were detected in coincidence with L3-M23M23 Auger electrons, and the experiment was performed at 343.6- and 344.9-eV electron impact to tune the energy loss to the energy of the dipole-allowed and the dipole-forbidden excitations, respectively. The resonant Auger spectra are obtained upon subtraction of the overlapping signal due to the outer-shell ionization, which was recorded at 340-eV electron-impact energy. The most intense groups of Auger transitions from 2p3/2-14s (J=1,2) and 2p3/2-14p (J=0,1,2,3) states are identified by comparison with the results of the two-step model, based on distorted-wave Born approximation with exchange and multiconfiguration descriptions of the relaxed states. The 4 s spectrum displays a substantially larger shake-up contribution than the one observed in photoexcitation experiments, which may be explained by the interference of the resonant decay path with the direct ionization excitation of the Ar 3p subshell. The majority of the observed 4p signal is assigned to the monopole and quadrupole excitations of the ground state.

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

    International Nuclear Information System (INIS)

    The full text of the publication follows. 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 iodo-benzamides or analogs are known to possess specific affinity for melanoma tissue. New hetero-aromatic derivatives have been designed with a cytotoxic moiety and termed DNA intercalating agents. These compounds could be applied in targeted radionuclide therapy using 125I, Auger electrons emitter which gives high-energetic 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 125I, the two compounds induced in vitro a significant radiotoxicity on B16F0 melanoma cells. The acridine compound, ICF01040, appeared more radio toxic than the acridone compound, ICF01035. While cellular uptake was similar for both compounds, SIMS analysis and in vitro protocol showed a stronger affinity for melanin with ICF01035, which was able to induce a predominant scavenging process in the melanosome and restrict access to the nucleus. Nevertheless, an important radiotoxicity was measured for the two compounds while the nuclear accumulation was low. Indeed, even if nuclear localization remains the main target sensitive to Auger electrons, the cell membrane remains sensitive to 125I decays. So, these compounds may induce secondary toxic effects of irradiation, such as membrane lipid damage. Conducted to current experiments are evaluate such hypothesis. Taken together, these results suggest that ICF01040 is a better candidate for application in targeted radionuclide therapy using 125I. The next step will be in vivo evaluation, where high tumoral vectorization gives promising perspectives

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

    Science.gov (United States)

    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. Electron spectrometer for gas-phase spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bozek, J.D.; Schlachter, A.S. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    An electron spectrometer for high-resolution spectroscopy of gaseous samples using synchrotron radiation has been designed and constructed. The spectrometer consists of a gas cell, cylindrical electrostatic lens, spherical-sector electron energy analyzer, position-sensitive detector and associated power supplies, electronics and vacuum pumps. Details of the spectrometer design are presented together with some representative spectra.

  11. Narrow electron injector for ballistic electron spectroscopy

    International Nuclear Information System (INIS)

    A three-terminal hot electron transistor is used to measure the normal energy distribution of ballistic electrons generated by an electron injector utilizing an improved injector design. A triple barrier resonant tunneling diode with a rectangular transmission function acts as a narrow (1 meV) energy filter. An asymmetric energy distribution with its maximum on the high-energy side with a full width at half maximum of ΔEinj=10 meV is derived. [copyright] 2001 American Institute of Physics

  12. X-ray Photoelectron Spectroscopy Database (Version 4.1)

    Science.gov (United States)

    SRD 20 X-ray Photoelectron Spectroscopy Database (Version 4.1) (Web, free access)   The NIST XPS Database gives access to energies of many photoelectron and Auger-electron spectral lines. The database contains over 22,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines.

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

    Energy Technology Data Exchange (ETDEWEB)

    Videla, M., E-mail: mariela.videla@iteda.cnea.gov.ar [Instituto de Tecnologías en Detección de Astropartículas (CNEA, CONICET, UNSAM) Centro Atómico Constituyentes, Avda. Gral. Paz 1499 (1650) San Martin, Pcia. de Buenos Aires (Argentina); Platino, M., E-mail: manuel.platino@iteda.cnea.gov.ar [Instituto de Tecnologías en Detección de Astropartículas (CNEA, CONICET, UNSAM) Centro Atómico Constituyentes, Avda. Gral. Paz 1499 (1650) San Martin, Pcia. de Buenos Aires (Argentina); García, B. [Instituto de Tecnologías en Detección y Astropartículas, (CNEA, CONICET, UNSAM) Regional Cuyo, Azopardo 313 (5501) Godoy Cruz, Pcia. de Mendoza (Argentina); Universidad Tecnológica Nacional, Facultad Regional Mendoza Rodriguez 273, Ciudad Mendoza, CP (M5502AJE) (Argentina); Almela, A. [Instituto de Tecnologías en Detección de Astropartículas (CNEA, CONICET, UNSAM) Centro Atómico Constituyentes, Avda. Gral. Paz 1499 (1650) San Martin, Pcia. de Buenos Aires (Argentina); Vega, G. de la [Instituto de Tecnologías en Detección y Astropartículas, (CNEA, CONICET, UNSAM) Regional Cuyo, Azopardo 313 (5501) Godoy Cruz, Pcia. de Mendoza (Argentina); and others

    2015-08-11

    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 m{sup 2} 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.

  14. Computer controlled SEM with Schottky cathode for imaging in slow and Auger electrons

    Czech Academy of Sciences Publication Activity Database

    Hrnčiřík, Petr; Müllerová, Ilona

    Brno: FEKT VUT Brno, 2002, s. -. [EEICT 2002. Brno (CZ), 25.04.2002] Institutional research plan: CEZ:AV0Z2065902 Keywords : ultrahighvacuum * scanning electron microscope * surface analysis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  15. Non-exponential Auger decay

    OpenAIRE

    Ishkhanyan, A. M.; Krainov, V. P.

    2015-01-01

    We discuss the possibility of non-exponential Auger decay of atoms irradiated by X-ray photons. This effect can occur at times, which are greater than the lifetime of a system under consideration. The mechanism for non-exponential depletion of an initial quasi-stationary state is the cutting of the electron energy spectrum of final continuous states at small energies. Then the Auger decay amplitude obeys power-law dependence on long observation times.

  16. Dosimetry at the sub-cellular scale of Auger-electron emitter (99m)Tc in a mouse single thyroid follicle.

    Science.gov (United States)

    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

  17. Spherical electrostatic electron spectrometer for Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Benczer-Koller, N.; Kolk, B.

    1977-01-01

    A high transmission spherical electrostatic electron spectrometer was constructed for combined Moessbauer and conversion electron spectroscopies. To date, a transmission of 7% and an energy resolution of 2.5% at 14 keV were achieved for a source of 1 cm diameter.

  18. Electron spectroscopy of rubber and resin-based composites containing 2D carbon

    International Nuclear Information System (INIS)

    Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for the gaskets or sealants, were prepared by ultrasonically assisted latex-mixing exfoliation and in-situ reduction process, with two vulcanization approaches: roll-mixing and hot-pressing. Also the resin-based composites, filled with micro-particles of Ag and graphene or carbon nanotubes, have been studied. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam and X-ray photons, has been investigated in different composite materials containing graphene and carbon nanotubes. A spectroscopic method for 2D carbon recognition, based on the Dx parameter which is determined from C KVV signal excited by X-ray photons, was proposed and verified. Even a small content of graphene in different types of composites was sufficient for this recognition due to the dominating presence of graphene on the surface of composites. - Highlights: • Chemical composition of the rubber composites was determined by XPS. • Auger spectrum of carbon was used for graphene identification in composites. • Small content of graphene was sufficient for its recognition from the D parameter

  19. Electron spectroscopy of rubber and resin-based composites containing 2D carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kaciulis, S., E-mail: saulius.kaciulis@ismn.cnr.it [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Mezzi, A.; Balijepalli, S.K. [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Lavorgna, M. [Institute of Polymers, Composites and Biomaterials, IPCB-CNR, P.le Fermi, 80055 Napoli (Italy); Xia, H.S. [State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065 Sichuan (China)

    2015-04-30

    Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for the gaskets or sealants, were prepared by ultrasonically assisted latex-mixing exfoliation and in-situ reduction process, with two vulcanization approaches: roll-mixing and hot-pressing. Also the resin-based composites, filled with micro-particles of Ag and graphene or carbon nanotubes, have been studied. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam and X-ray photons, has been investigated in different composite materials containing graphene and carbon nanotubes. A spectroscopic method for 2D carbon recognition, based on the D{sub x} parameter which is determined from C KVV signal excited by X-ray photons, was proposed and verified. Even a small content of graphene in different types of composites was sufficient for this recognition due to the dominating presence of graphene on the surface of composites. - Highlights: • Chemical composition of the rubber composites was determined by XPS. • Auger spectrum of carbon was used for graphene identification in composites. • Small content of graphene was sufficient for its recognition from the D parameter.

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

    International Nuclear Information System (INIS)

    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 (SER10) 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, SER10 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, SER10 values were 4.1 ± 0.2, 3.0 ± 0.1, and 2.0 ± 0.1, respectively, which yielded SER10 ratios (35 keV:4 MV) of 1.6 ± 0.1, 1.4 ± 0.1, and 1.3 ± 0.1, respectively. Conclusions: SER10 increases monotonically with percent thymidine replacement by IUdR for both modalities. As compared to 4-MV x-rays, 35-keV photons produce enhanced SER10 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.

    Science.gov (United States)

    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. Electron spectroscopy of collisional excited atoms

    International Nuclear Information System (INIS)

    In this thesis measurements are described in which coincidences are detected between scattered projectiles and emitted electrons. This yields information on two-electron excitation processes. In order to show what can be learnt from coincidence experiments a detailed theoretical analysis is given. The transition amplitudes, which contain all the information, are introduced (ch.2). In ch.3 the experimental set-up is shown. The results for the Li+-He system are shown in ch. 7 and are compared with predictions based on the Molecular-Orbitalmodel which however does not account for two-excitation mechanisms. With the transition amplitudes also the wave function of the excited atom has been completely determined. In ch.8 the shape of the electron cloud, induced by the collision, is derived from the amplitudes. The relation between the oscillatory motion of this cloud after the collision and the correlation between the two electrons of the excited atom is discussed. In ch. 6 it is shown that the broad structures in the non-coincident energy spectra of the Li+-He system are erroneously interpretated as a result of electron emission from the (Li-He)+-quasimolecule. A model is presented which explains, based on the results obtained from the coincidence measurements, these broad structures. In ch. 4 the Post-Collision Interaction process is treated. It is shown that for high-energy collisions, in contrast with general assumptions, PCI is important. In ch. 5 the importance of PCI-processes in photoionization of atoms, followed by Auger decay, are studied. From the formulas derived in ch. 4 simple analytical results are obtained. These are applied to recent experiments and good agreement is achieved. 140 refs.; 55 figs.; 9 tabs

  3. Investigation of SiGe/Si heterostructures using state-of-the-art Auger Nanoprobes

    International Nuclear Information System (INIS)

    The capabilities of nano-Auger were assessed for the characterization of SiGe multilayers epitaxially grown on Si(001) wafers. Reference sample consisting in stack of (300–500)-nm thick SiGe layers with a Ge content increasing in discrete steps from 6 to 30 % (as determined by X-ray diffraction) were used to that end. Composition measurements were performed on cross-sections with localized Auger Electron Spectroscopy using point analysis. The promising results obtained should enable in the near future high performance Auger mapping of real devices. The effect of native oxide removal either by argon sputtering or by HF etching was also addressed. Complementary results were otherwise obtained with Auger depth profiling using argon sputtering with Zalar rotation.

  4. Influence of host matrices on krypton electron binding energies and KLL Auger transition energies

    Czech Academy of Sciences Publication Activity Database

    Inoyatov, A. K.; Perevoshchikov, L. L.; Kovalík, Alojz; Filosofov, D. V.; Yushkevich, Yu. V.; Ryšavý, Miloš; Lee, B. Q.; Kibédi, T.; Stuchbery, A. E.; Zhdanov, V. S.

    2014-01-01

    Roč. 197, DEC (2014), s. 64-71. ISSN 0368-2048 R&D Projects: GA ČR(CZ) GAP203/12/1896; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : Kr-83 * Rb-83 * Sr-83 * electron binding energy * KLL transitions * natural atomic level width * multiconfiguration Dirac-Fock calculations Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.436, year: 2014

  5. Dynamical effects in electron spectroscopy.

    Science.gov (United States)

    Zhou, Jianqiang Sky; Kas, J J; Sponza, Lorenzo; Reshetnyak, Igor; Guzzo, Matteo; Giorgetti, Christine; Gatti, Matteo; Sottile, Francesco; Rehr, J J; Reining, Lucia

    2015-11-14

    One of the big challenges of theoretical condensed-matter physics is the description, understanding, and prediction of the effects of the Coulomb interaction on materials properties. In electronic spectra, the Coulomb interaction causes a renormalization of energies and change of spectral weight. Most importantly, it can lead to new structures, often called satellites. These can be linked to the coupling of excitations, also termed dynamical effects. State-of-the-art methods in the framework of many-body perturbation theory, in particular, the widely used GW approximation, often fail to describe satellite spectra. Instead, approaches based on a picture of electron-boson coupling such as the cumulant expansion are promising for the description of plasmon satellites. In this work, we give a unified derivation of the GW approximation and the cumulant expansion for the one-body Green's function. Using the example of bulk sodium, we compare the resulting spectral functions both in the valence and in the core region, and we discuss the dispersion of quasi-particles and satellites. We show that self-consistency is crucial to obtain meaningful results, in particular, at large binding energies. Very good agreement with experiment is obtained when the intrinsic spectral function is corrected for extrinsic and interference effects. Finally, we sketch how one can approach the problem in the case of the two-body Green's function, and we discuss the cancellation of various dynamical effects that occur in that case. PMID:26567648

  6. Dynamical effects in electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianqiang Sky, E-mail: jianqiang.zhou@polytechnique.edu; Reshetnyak, Igor; Giorgetti, Christine; Sottile, Francesco; Reining, Lucia [Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM-IRAMIS, Université Paris-Saclay, F-91128 Palaiseau (France); Kas, J. J.; Rehr, J. J. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Sponza, Lorenzo [Department of Physics, King’s College London, London WC2R 2LS (United Kingdom); Guzzo, Matteo [Institut für Physik und IRIS Adlershof, Humboldt-Universität zu Berlin, D-12489 Berlin (Germany); Gatti, Matteo [Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM-IRAMIS, Université Paris-Saclay, F-91128 Palaiseau (France); Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette (France)

    2015-11-14

    One of the big challenges of theoretical condensed-matter physics is the description, understanding, and prediction of the effects of the Coulomb interaction on materials properties. In electronic spectra, the Coulomb interaction causes a renormalization of energies and change of spectral weight. Most importantly, it can lead to new structures, often called satellites. These can be linked to the coupling of excitations, also termed dynamical effects. State-of-the-art methods in the framework of many-body perturbation theory, in particular, the widely used GW approximation, often fail to describe satellite spectra. Instead, approaches based on a picture of electron-boson coupling such as the cumulant expansion are promising for the description of plasmon satellites. In this work, we give a unified derivation of the GW approximation and the cumulant expansion for the one-body Green’s function. Using the example of bulk sodium, we compare the resulting spectral functions both in the valence and in the core region, and we discuss the dispersion of quasi-particles and satellites. We show that self-consistency is crucial to obtain meaningful results, in particular, at large binding energies. Very good agreement with experiment is obtained when the intrinsic spectral function is corrected for extrinsic and interference effects. Finally, we sketch how one can approach the problem in the case of the two-body Green’s function, and we discuss the cancellation of various dynamical effects that occur in that case.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  10. Proximity Scanning Transmission Electron Microscopy/Spectroscopy

    CERN Document Server

    Hwang, Ing-Shouh

    2016-01-01

    Here a new microscopic method is proposed to image and characterize very thin samples like few-layer materials, organic molecules, and nanostructures with nanometer or sub-nanometer resolution using electron beams of energies lower than 20 eV. The microscopic technique achieves high resolution through the proximity (or near-field) effect, as in scanning tunneling microscopy (STM), while it also allows detection of transmitted electrons for imaging and spectroscopy, as in scanning transmission electron microscopy (STEM). This proximity transmission electron microscopy (PSTEM) does not require any lens to focus the electron beam. It also allows detailed characterization of the interaction of low-energy electron with materials. PSTEM can operate in a way very similar to scanning tunneling microscopy, which provides high-resolution imaging of geometric and electronic structures of the sample surface. In addition, it allows imaging and characterization of the interior structures of the sample based on the detected...

  11. Determination of the inelastic mean free path of electrons in polythiophenes using elastic peak electron spectroscopy method

    Science.gov (United States)

    Lesiak, B.; Kosinski, A.; Jablonski, A.; Kövér, L.; Tóth, J.; Varga, D.; Cserny, I.; Zagorska, M.; Kulszewicz-Bajer, I.; Gergely, G.

    2001-04-01

    The inelastic mean free path (IMFP) is an important parameter for quantitative surface characterisation by Auger electron spectroscopy, X-ray photoelectron spectroscopy or electron energy loss spectroscopy. An extensive database of the IMFPs for selected elements, inorganic and organic compounds has been recently published by Powell and Jablonski. As it follows from this compilation, the published material on IMFPs for conductive polymers is very limited. Selected polymers, such as polyacetylenes and polyanilines, have been investigated only recently. The present study is a continuation of the research on IMFPs determination in conductive polymers using the elastic peak electron spectroscopy (EPES) method. In the present study three polythiophene samples have been studied using high energy resolution spectrometer and two standards: Ni and Ag. The resulting experimental IMFPs are compared to the respective IMFP values determined using the predictive formulae proposed by Tanuma and Powell (TPP-2M) and by Gries (G1), showing a good agreement. The scatter between the experimental and predicted IMFPs in polythiophenes is evaluated. The statistical and systematic errors, their sources and the possible contributions to the systematic error due to influence of the accuracy of the input parameters, such as the surface composition and density, on the IMFPs derived from the experiments and Monte Carlo calculations, are extensively discussed.

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

    Science.gov (United States)

    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

  13. The KLL Auger spectrum of Cu-65 measured from the EC decay of Zn-65

    Czech Academy of Sciences Publication Activity Database

    Inoyatov, A. K.; Perevoshchikov, L. L.; Kovalík, Alojz; Filosofov, D. V.; Gorozhankin, V. M.

    2009-01-01

    Roč. 171, 1-3 (2009), s. 53-56. ISSN 0368-2048 Institutional research plan: CEZ:AV0Z10480505 Keywords : Electron spectroscopy * Auger effect * KLL transitions Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.942, year: 2009

  14. The electronic paramagnetic resonance spectroscopy - Applications

    International Nuclear Information System (INIS)

    This collective book addresses the various applications of electronic paramagnetic resonance (EPR) spectroscopy. The addressed issues (and chapters) are: the dosimetry of ionizing radiation, the tracing of natural organic matter within drainage basins, the detection and characterisation of free radicals after spin trapping, copper complexation by peptides involved in neuro-degenerative diseases, crystal chemistry of clay minerals and alteration process and evolution of continental surfaces, structure and catalytic mechanism of redox enzymes, the primitive carbonated matter, use of paramagnetic probes to study structural transitions within proteins, organic radicals and molecular magnetism, EPR of transient magnetic species, characterization of contrast agents for magnetic resonance imaging, and fundamentals and applications of ferromagnetic resonance spectroscopy. Appendices present the principles of magnetic resonance (Bloch equations and pulse methods), the pulse EPR (ESEEM, HYSCORE and PELDOR experiments), the principle of continuous wave ENDOR (Electron-nuclear double resonance) spectroscopy, and the protein functions

  15. Auger electron spectra in 5.5 MeV/amu Nesup(q+) and Arsup(q+) ion impact on Ne

    International Nuclear Information System (INIS)

    A study of Ne K-Auger spectra induced by 5.5 MeV/amu Ne3+, Ne10+, Ar6+ and Ar17+ heavy ions on Ne is presented. Some average quantities (the centroid energy of KLL Auger spectra, the average number of L vacancies produced simultaneously with the K vacancy, the effective charge of the projectile in the actual process, Zsub(eff), the satellite to total intensity ratio) characterizing the KLsup(n) ionization process have been extracted from these spectra. Relative K-shell ionization cross sections and KLM to KLL cross section ratios have also been evaluated. The deduced experimental Zsub(eff) values have been compared to the results of plane wave Born approximation (PWBA) and binary encounter approximation (BEA) calculations. A simple model calculat on is made in an attempt to nterpret the variation of the probability for the ejection of an L-shell electron (Psub(L)) as a function of Zsub(eff)/vsub(p). Some statements regarding individual lines and groups in the Auger spectra are made

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

    Science.gov (United States)

    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.

  17. Free-Electron Laser-Powered Electron Paramagnetic Resonance Spectroscopy

    OpenAIRE

    Takahashi, S.; Brunel, L.-C.; Edwards, D. T.; Tol, J.; Ramian, G.; Han, S.; Sherwin, M. S.

    2012-01-01

    Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired electron spins in solids and liquids to reveal local structure and dynamics; for example, EPR has elucidated parts of the structure of protein complexes that have resisted all other techniques in structural biology. EPR can also probe the interplay of light and electricity in organic solar cells and light-emitting diodes, and the origin of decoherence in condensed matter, which is of fundamental importance to the develop...

  18. High-resolution Auger spectroscopy on 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions after excitation by helium

    International Nuclear Information System (INIS)

    In this thesis the atomic structure of highly excited Ar6+ and Ar7+ ions was studied. For this 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions of a heavy ion accelerator were excited by a He gas target to autoionizing states and the Auger electrons emitted in the decay were measured in highly-resolving state. The spectra were taken under an observational angle of zero degree relative to the beam axis in order to minimize the kinematical broadening of the Auger lines. (orig./HSI)

  19. Two-dimensional vibrational-electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  20. Two-dimensional vibrational-electronic spectroscopy

    International Nuclear Information System (INIS)

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (νCN) and either a ligand-to-metal charge transfer transition ([FeIII(CN)6]3− dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN)5FeIICNRuIII(NH3)5]− dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific νCN modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a wide range of complex molecular, material, and biological systems

  1. Theoretical and experimental study of the double ionization by electron impact involving the Auger effect: processes and exchanges interferences; Etude theorique et experimentale de la double ionisation par impact electronique incluant l'effet auger: interferences d'echanges et de processus

    Energy Technology Data Exchange (ETDEWEB)

    Catoire, F

    2006-09-15

    In this work, double ionisation mechanisms of argon by electron impact in which the Auger effect is included have been studied as a function of the incident electron energy. Five and six fold differential cross sections in angle and in energy have been measured and analysed in a coplanar geometry. The efficiency of the apparatus has been improved by the use of a new toroidal analyser. For the first time, the six fold differential cross section in which the Auger electron and the ejected electron with identical kinetic energies (205 eV) are involved, was measured at an incident energy of 956 eV in the case of argon. In the theoretical models developed during this work, the triple continuum is represented by a manifold of coulomb waves describing the interaction of all electrons with the residual ion. Exchange effects between electrons were also included in the models. Comparison between experimental and theoretical results allows to study the relative contribution of the Auger process and the direct double ionisation on the angular dependence five fold differential cross section. In particular, the Auger process contribution seems to become increasingly important as the incident energy is increased.

  2. The chemical structure of the ZnO/SiC heterointerface as revealed by electron spectroscopies

    International Nuclear Information System (INIS)

    ZnO layers were deposited on 6H-SiC single crystalline wafers by radio frequency magnetron sputtering. The chemical structure of the ZnO/SiC interface was studied by x-ray photoelectron and x-ray excited Auger electron spectroscopy. A complex chemical structure, involving not only silicon–carbon and zinc–oxygen bonds but also silicon–oxygen and zinc–silicon–oxygen bonds was revealed to form at the ZnO/SiC interface. Based on the comparison with the presumably inert (i.e. chemically abrupt) ZnO/Mo interface, it was concluded that a willemite-like zinc silicate (i.e. Zn2SiO4) interface species develops between ZnO and SiC. The presence of this species at the ZnO/SiC interface will affect the electronic structure of the heterojunction and thus needs to be considered for device optimization. (paper)

  3. Photoelectron spectroscopy bulk and surface electronic structures

    CERN Document Server

    Suga, Shigemasa

    2014-01-01

    Photoelectron spectroscopy is now becoming more and more required to investigate electronic structures of various solid materials in the bulk, on surfaces as well as at buried interfaces. The energy resolution was much improved in the last decade down to 1 meV in the low photon energy region. Now this technique is available from a few eV up to 10 keV by use of lasers, electron cyclotron resonance lamps in addition to synchrotron radiation and X-ray tubes. High resolution angle resolved photoelectron spectroscopy (ARPES) is now widely applied to band mapping of materials. It attracts a wide attention from both fundamental science and material engineering. Studies of the dynamics of excited states are feasible by time of flight spectroscopy with fully utilizing the pulse structures of synchrotron radiation as well as lasers including the free electron lasers (FEL). Spin resolved studies also made dramatic progress by using higher efficiency spin detectors and two dimensional spin detectors. Polarization depend...

  4. MsSpec-1.0: A multiple scattering package for electron spectroscopies in material science

    Science.gov (United States)

    Sébilleau, Didier; Natoli, Calogero; Gavaza, George M.; Zhao, Haifeng; Da Pieve, Fabiana; Hatada, Keisuke

    2011-12-01

    We present a multiple scattering package to calculate the cross-section of various spectroscopies namely photoelectron diffraction (PED), Auger electron diffraction (AED), X-ray absorption (XAS), low-energy electron diffraction (LEED) and Auger photoelectron coincidence spectroscopy (APECS). This package is composed of three main codes, computing respectively the cluster, the potential and the cross-section. In the latter case, in order to cover a range of energies as wide as possible, three different algorithms are provided to perform the multiple scattering calculation: full matrix inversion, series expansion or correlation expansion of the multiple scattering matrix. Numerous other small Fortran codes or bash/csh shell scripts are also provided to perform specific tasks. The cross-section code is built by the user from a library of subroutines using a makefile. Program summaryProgram title: MsSpec-1.0 Catalogue identifier: AEJT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 504 438 No. of bytes in distributed program, including test data, etc.: 14 448 180 Distribution format: tar.gz Programming language: Fortran 77 Computer: Any Operating system: Linux, MacOs RAM: Bytes Classification: 7.2 External routines: Lapack ( http://www.netlib.org/lapack/) Nature of problem: Calculation of the cross-section of various spectroscopies. Solution method: Multiple scattering. Running time: The test runs provided only take a few seconds to run.

  5. Temperature effects on Li4Ti5O12 electrode/electrolyte interfaces at the first cycle: A X-ray Photoelectron Spectroscopy and Scanning Auger Microscopy study

    Science.gov (United States)

    Gieu, J.-B.; Courrèges, C.; El Ouatani, L.; Tessier, C.; Martinez, H.

    2016-06-01

    Li4Ti5O12-based negative electrodes for Lithium-ion batteries are of interest because of the high reversibility of Li+ insertion/extraction. In this study, the surface of cycled electrodes is analysed by X-ray Photoelectron Spectroscopy (XPS) and Scanning Auger Microscopy (SAM) to investigate the effects of cycling temperature (room temperature, 60 °C and 85 °C) upon the solid electrolyte interphase (SEI) formation, which plays a major role in batteries electrochemical performances. Half-cells, with a vinylene carbonate containing electrolyte, are galvanostatically cycled at different steps of the first cycle: the mid-plateau during the first discharge, the end of the first discharge at 1.2 V and the end of the first charge at 2.0 V. XPS analysis evidences that higher temperatures promote the formation of a thicker SEI, which can explain the increase of the irreversible capacity with temperature. SAM mappings (allowing high spatial resolution ∼10-100 nm) evidence that this SEI homogeneously covers the electrode surface, regardless of the cycling temperature. During charge, the SEI is partially dissolved at room temperature, more slightly at 60 °C whereas at 85 °C, no clear evidence of layer thinning is observed. The SEI chemical composition is also investigated and reveals a majority of organic species and an increasing proportion of LiF with the temperature.

  6. Auger Physicists visit CMS

    CERN Multimedia

    Hoch, Michael

    2012-01-01

    Visit at CERN P5 CMS in the experimental cavern Alan Watson, Auger Spokesperson Emeritus, University of Leeds; Jim Cronin, Nobel Laureate, Auger Spokesperson Emeritus, University of Chicago; Jim Virdee, CMS Former Spokesperson, Imperial College; Jim Matthews, Auger Co-Spokesperson, Louisiana State University

  7. Temperature dependence of photoluminescence spectra of bilayer two-dimensional electron gases in LaAlO3/SrTiO3 superlattices: coexistence of Auger recombination and single-carrier trapping

    Directory of Open Access Journals (Sweden)

    H. J. Harsan Ma

    2015-06-01

    Full Text Available We report emerging photoluminescence (PL of bilayer two-dimensional electron gases (2DEG in LaAlO3/SrTiO3 (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.

  8. Temperature dependence of photoluminescence spectra of bilayer two-dimensional electron gases in LaAlO3/SrTiO3 superlattices: coexistence of Auger recombination and single-carrier trapping

    International Nuclear Information System (INIS)

    We report emerging photoluminescence (PL) of bilayer two-dimensional electron gases (2DEG) in LaAlO3/SrTiO3 (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

  9. Multidimensional Electronic Spectroscopy of Photochemical Reactions.

    Science.gov (United States)

    Nuernberger, Patrick; Ruetzel, Stefan; Brixner, Tobias

    2015-09-21

    Coherent multidimensional electronic spectroscopy can be employed to unravel various channels in molecular chemical reactions. This approach is thus not limited to analysis of energy transfer or charge transfer (i.e. processes from photophysics), but can also be employed in situations where the investigated system undergoes permanent structural changes (i.e. in photochemistry). Photochemical model reactions are discussed by using the example of merocyanine/spiropyran-based molecular switches, which show a rich variety of reaction channels, in particular ring opening and ring closing, cis-trans isomerization, coherent vibrational wave-packet motion, radical ion formation, and population relaxation. Using pump-probe, pump-repump-probe, coherent two-dimensional and three-dimensional, triggered-exchange 2D, and quantum-control spectroscopy, we gain intuitive pictures on which product emerges from which reactant and which reactive molecular modes are associated. PMID:26382095

  10. Stimulated excitation electron microscopy and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Howie, A.

    2015-04-15

    Recent advances in instrumentation for electron optics and spectroscopy have prompted exploration of ultra-low excitations such as phonons, bond vibrations and Johnson noise. These can be excited not just with fast electrons but also thermally or by other external sources of radiation. The near-field theory of electron energy loss and gain provides a convenient platform for analysing these processes. Possibilities for selected phonon mapping and imaging are discussed. Effects should certainly be observable in atomic resolution structure imaging but diffraction contrast imaging could perhaps be more informative. Additional exciting prospects to be explored include the transition from phonon excitation to single atom recoil and the boosting of energy loss and gain signals with tuned laser illumination. - Highlights: • Electron energy gains and losses measure thermal or laser boosting of excitations. • Electron energy gains and losses are conveniently analysed by near field theory. • Diffraction contrast theory is relevant for phonon imaging by electrons. • The transition from phonon excitation to single atom recoil deserves study.

  11. Stimulated excitation electron microscopy and spectroscopy

    International Nuclear Information System (INIS)

    Recent advances in instrumentation for electron optics and spectroscopy have prompted exploration of ultra-low excitations such as phonons, bond vibrations and Johnson noise. These can be excited not just with fast electrons but also thermally or by other external sources of radiation. The near-field theory of electron energy loss and gain provides a convenient platform for analysing these processes. Possibilities for selected phonon mapping and imaging are discussed. Effects should certainly be observable in atomic resolution structure imaging but diffraction contrast imaging could perhaps be more informative. Additional exciting prospects to be explored include the transition from phonon excitation to single atom recoil and the boosting of energy loss and gain signals with tuned laser illumination. - Highlights: • Electron energy gains and losses measure thermal or laser boosting of excitations. • Electron energy gains and losses are conveniently analysed by near field theory. • Diffraction contrast theory is relevant for phonon imaging by electrons. • The transition from phonon excitation to single atom recoil deserves study

  12. Positron lifetime measurements and positron-annihilation induced auger electron spectroscpy using slow positron beams; Teisoku yodenshi bimu wo mochiita yodenshi jumyo sokutei oyobi yodenshi shometsu reiki oje denshi bunko

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, R. [Electrotechnical Lab., Tsukuba (Japan)

    1996-02-20

    Slow positron beam with less than several eV can be controlled freely such as accelerating, throttling the beam size, shortening the pulse or making pulse with short time width and so forth. These low positron beams are applied to various measurements like Doppler broadening measurement of annihilation {gamma} rays or lifetime measurement of positron, and secondary particle measurements using positron microscope, positron electron ray diffraction, flight time method and so forth. In particular, these recent years, high intensity slow positron beams were possible using accelerators like electron linac and its application is increasing. In this report, pulse shortening method for high intensity slow positron beam, and incidence energy variable positron lifetime measurement method using this slow pulsed beam and flight time type positron-annihilation-induced auger electron spectroscopy are outlined. In future, these measurements can be possible to carry out with high resolution and also with high counting rate if higher intensity monochromatic excellent positron beam than present one is produced. 31 refs., 5 figs.

  13. Implementation of the Electron conversion Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    In the present work has been exposed the principles of the Conversion Moessbauer Electron Spectroscopy and its possibilities of application. Is also described the operation of the parallel plate avalanche detector made at the CEADEN starting from modifications done to the Gancedo's model and is exposed examples of the use of this detector in the characterization of corroded surfaces, with chemical cleaning and in samples of welded joints. The experiences obtained of this work were extended to the National Polytechnic Institute of Mexico where a similar detector, made in our center, was installed there

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

    Science.gov (United States)

    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.

  15. Observation of X-ray and Auger electron spectra in a 4π proportional counter for 4π(e, X)–γ coincidence measurements

    International Nuclear Information System (INIS)

    For the standardization of electron capture nuclides followed by γ-transitions, the 4π(e, X)–γ coincidence counting method is mainly adopted. To examine how the spectra of the (e, X) channel change with gas nature and pressure, pulse-height spectrum measurements of signals from a 4π pressurized proportional counter were carried out under various conditions for 54Mn and 88Y sources together with 4π(e, X)–γ coincidence counting. The spectra were measured for each half of the counter and for the combined 4π signal. The nature of counting gas (P-10 or methane) and its pressure was reflected in the X-ray peak intensity, and the Auger electron spectra were influenced significantly by the absorption in a thin VYNS film and the source conditions. In the measurements, we employed a pill-box type 4π counter in which the anodes were very thin gold-coated tungsten wires (30 μm ∅). In this system, spectra down to 0.2 keV were clearly seen. The gas pressure can be raised up to 0.6 MPa. Counting electronics used for 4π(e, X)–γ coincidence measurements were conventional modules and a list mode two-parameter data acquisition system. - Highlights: • Spectra of 54Mn and 88Y in a 4π proportional counter measured under various conditions. • Spectra due to X-rays and Auger electrons were clearly seen down to 0.2 keV. • Pulse spectra measured from each half of 4π counter (with P-10 gas or methane). • 4π(e, X)–γ coincidence measurements were also carried out

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

    Science.gov (United States)

    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.

  17. Auger Emitting Radiopharmaceuticals for Cancer Therapy

    Science.gov (United States)

    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.

  18. Drill-auger

    Energy Technology Data Exchange (ETDEWEB)

    Levkovich, P.E.; Bratisheva, L.L.; Savich, N.S.

    1981-01-01

    The author proposes a drill-auger with a drilling platform, a sectional auger-bit with a drilling-bit crown, a rotational mechanism, and a feed mechanism with vertical chain grippers. Borehole drilling operations are made more effective by drilling from a single drill platform attitude for the entirety of the auger-bit length (which is equal to the screw length). The chain teeth protrude from the auger to a diameter equal to the height of the teeth. The rotary mechanism is platform mounted with two symmetrically deployed rollers having teeth capable of kinematically interfacing with the auger teeth. The feed mechanism consists of a hydraulic jack deployed between the vertical chain protrusion and the auxiliary grippers which are themselves attached in a hinge-like fashion to the hydraulic-jack cylinder and are capable of interfacing with sections of the auger stem.

  19. Auger electron emitter against multiple myeloma - targeted endo-radio-therapy with 125I-labeled thymidine analogue 5-iodo-4'-thio-2'-deoxyuridine

    International Nuclear Information System (INIS)

    Introduction: Multiple myeloma (MM) is a plasma cell malignancy characterized by accumulation of malignant, terminally differentiated B cells in the bone marrow. Despite advances in therapy, MM remains an incurable disease. Novel therapeutic approaches are, therefore, urgently needed. Auger electron-emitting radiopharmaceuticals are attractive for targeted nano-irradiation therapy, given that DNA of malignant cells is selectively addressed. Here we evaluated the antimyeloma potential of the Auger electron-emitting thymidine analogue 125I-labeled 5-iodo-4'-thio-2'-deoxyuridine ([125I]ITdU). Methods: Cellular uptake and DNA incorporation of [125I]ITdU were determined in fluorodeoxyuridine-pretreated KMS12BM, U266, dexamethasone-sensitive MM1.S and -resistant MM1.R cell lines. The effect of stimulation with interleukin 6 (IL6) or insulin-like growth factor 1 (IGF1) on the intracellular incorporation of [125I]ITdU was investigated in cytokine-sensitive MM1.S and MM1.R cell lines. Apoptotic cells were identified using Annexin V. Cleavage of caspase 3 and PARP was visualized by Western blot. DNA fragmentation was investigated using laddering assay. Therapeutic efficiency of [125I]ITdU was proven by clonogenic assay. Results: [125I]ITdU was shown to be efficiently incorporated into DNA of malignant cells, providing a promising mechanism for delivering highly toxic Auger radiation emitters into tumor DNA. [125I]ITdU had a potent antimyeloma effect in cell lines representing distinct disease stages and, importantly, in cell lines sensitive or resistant to the conventional therapeutic agent, but was not toxic for normal plasma and bone marrow stromal cells. Furthermore, [125I]ITdU abrogated the protective actions of IL6 and IGF1 on MM cells. [125I]ITdU induced massive damage in the DNA of malignant plasma cells, which resulted in efficient inhibition of clonogenic growth. Conclusion: These studies may provide a novel treatment strategy for overcoming resistance to

  20. Improvement of depth selective electron Moessbauer spectroscopy for investigations of locally heterogenous nanosystems

    International Nuclear Information System (INIS)

    Full text: Active use of Moessbauer spectroscopy in various investigations including study of properties of locally heterogeneous systems stipulates continuous improvements of instrumental and methodical base. There has been developed a nondestructive method of depth selective conversion electron Moessbauer spectroscopy (DS CEMS) for obtaining of Moessbauer information from subsurface locally heterogeneous systems with depth resolution about several nm. Precise investigations by this method at a combined installation electron spectrometer - nuclear gamma resonance spectrometer are of special interest. Quality of such investigations first of all depends upon the possibilities of the electron spectrometer. There were found stipulated by the electron spectrometer conditions of achievement of the depth resolution close to physical nanolimit. There was achieved evident success in development of DS CEMS method at high-effective magnetic sector electron spectrometer with double focusing equipped with large area non-equipotential electron source (a sample under investigation) of and with the position-sensitive detector of electrons, which is similar to the detector. The present spectrometer satisfies the conditions found above. It allows also to work with low-energy electrons up to 500 eV including Auger electrons and electrons of true secondary emission. Thickness about several nm with the depth resolution about tenths of nm is studied in the last case at rather high efficiency of measurements. The main aspects of use of internal conversion electrons, Auger electrons and secondary electrons accompanying decay of Moessbauer levels of different nuclei in the method of depth selective electron Moessbauer spectroscopy (DS EMS) were considered. There were recommended optimal variants for use of either that type of electron irradiation and their combinations for a number of solved problems. The electron spectrometer with a sample at a boundary of the magnetic gap corresponds to

  1. Surface photovoltage and Auger electron spectromicroscopy studies of HfO{sub 2}/SiO{sub 2}/4H-SiC and HfO{sub 2}/Al{sub 2}O{sub 3}/4H-SiC structures

    Energy Technology Data Exchange (ETDEWEB)

    Domanowska, A., E-mail: Alina.Domanowska@polsl.pl [Department of Surface Physics and Nanostructures, Institute of Physics - Centre for Science and Education, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice (Poland); Miczek, M.; Ucka, R.; Matys, M.; Adamowicz, B. [Department of Surface Physics and Nanostructures, Institute of Physics - Centre for Science and Education, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice (Poland); Zywicki, J. [High-Tech International Services, Rome (Italy); Taube, A. [Institute of Electron Technology, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Korwin-Mikke, K. [Institute of Electron Technology, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Gieraltowska, S. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Sochacki, M. [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland)

    2012-08-15

    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 SiO{sub 2} or Al{sub 2}O{sub 3} buffer film and high-{kappa} HfO{sub 2} layer were investigated. The main aim was to estimate the influence of the passivation approach on the interface effective charge density (Q{sub eff}) 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{sup +} ion profiling. The structure HfO{sub 2}/SiO{sub 2}/4H-SiC exhibited slightly superior electronic properties in terms of Q{sub eff} (in the range of -10{sup 11} q cm{sup -2}).

  2. Electron-nuclear double resonance spectroscopy (and electron spin-echo envelope modulation spectroscopy) in bioinorganic chemistry

    OpenAIRE

    Hoffman, Brian M.

    2003-01-01

    This perspective discusses the ways that advanced paramagnetic resonance techniques, namely electron-nuclear double resonance (ENDOR) and electron spin-echo envelope modulation (ESEEM) spectroscopies, can help us understand how metal ions function in biological systems.

  3. Electronic properties of atomic layer deposition films, anatase and rutile TiO2 studied by resonant photoemission spectroscopy

    Science.gov (United States)

    Das, C.; Richter, M.; Tallarida, M.; Schmeisser, D.

    2016-07-01

    The TiO2 films are prepared by atomic layer deposition (ALD) method using titanium isopropoxide precursors at 250 °C and analyzed using resonant photoemission spectroscopy (resPES). We report on the Ti2p and O1s core levels, on the valence band (VB) spectra and x-ray absorption spectroscopy (XAS) data, and on the resonant photoelectron spectroscopy (resPES) profiles at the O1s and the Ti3p absorption edges. We determine the elemental abundance, the position of the VB maxima, the partial density of states (PDOS) in the VB and in the conduction band (CB) and collect these data in a band scheme. In addition, we analyze the band-gap states as well as the intrinsic states due to polarons and charge-transfer excitations. These states are found to cause multiple Auger decay processes upon resonant excitation. We identify several of these processes and determine their relative contribution to the Auger signal quantitatively. As our resPES data allow a quantitative analysis of these defect states, we determine the relative abundance of the PDOS in the VB and in CB and also the charge neutrality level. The anatase and rutile polymorphs of TiO2 are analyzed in the same way as the TiO2 ALD layer. The electronic properties of the TiO2 ALD layer are compared with the anatase and rutile polymorphs of TiO2. In our comparative study, we find that ALD has its own characteristic electronic structure that is distinct from that of anatase and rutile. However, many details of the electronic structure are comparable and we benefit from our spectroscopic data and our careful analysis to find these differences. These can be attributed to a stronger hybridization of the O2p and Ti3d4s states for the ALD films when compared to the anatase and rutile polymorphs.

  4. Conversion electron Moessbauer spectroscopy with very low energy (0 to 15 eV) electrons

    International Nuclear Information System (INIS)

    A very intensive peak of low energy electrons (≤15 eV) appears in the electron energy spectrum, measured by a high transmission magnetic spectrometer, if a negative voltage of more than about 20 volts is applied to the Moessbauer absorber. The MB-spectrum of enriched stainless steel, recorded with these electrons, shows a high resonance effect of about 700% with countrates of 103 sec-1, compared to 750% and 60 sec-1 at the K-edge. Two processes seem to be responsible with characteristic attenuation length of about 40 A and about 400 A. We conclude, that part of these electrons are produced directly by Moessbauer absorption and conversion, resulting in low energy Auger electron emission, showing a high surface sensitivity as well. (orig.)

  5. Electron spectroscopy on cuprates and ruthenates

    International Nuclear Information System (INIS)

    The electronic structure of the halo-oxocuprates and ruthenates, which are isostructural to the high temperature superconductor La2-xBaxCuO4, has been investigated with X-ray absorption and photoemission spectroscopy. The halo-oxocuprates exhibit a very stable stoichiometric phase. Sr2CuO2Cl2 has a valence band maximum in the middle of the Brillouin-zone approximately 0.5 eV below the Fermi level. The dispersion of this band along the anti Γ- anti X line agree quite well with calculations for the t-J model. The dispersion along a line 3 parallel to the anti Γ- anti M line is similar to the dispersion predicted for the t-J model. However, the energy position of this peak relative to the valence band maximum does not agrees with the model calculation. Improved agreement can be gained by introducing a diagnonal hopping term in the t-J model. X-ray absorption measurements on Sr2RuO4 indicate that the unoccupied states close to the Fermi level are mainly determined by Ru-4dxz,yz.xy orbitals hybridized with O-2pπ orbitals. A peak observed at 528.5 eV photon energy is probably related to the apical oxygen sites. A relatively high amount of holes close to the Fermi level have O 2pz character. The amount of holes close to the Fermi level with O 2pz character is approximately two times higher than the amount of holes with O 2px,y character

  6. Front-End Board with Cyclone V as a Test High-Resolution Platform for the Auger-Beyond-2015 Front End Electronics

    CERN Document Server

    Szadkowski, Zbigniew

    2014-01-01

    The surface detector (SD) array of the Pierre Auger Observatory containing at present 1680 water Cherenkov detectors spread over an area of 3000 km^2 started to operate since 2004. The currently used Front-End Boards are equipped with no-more produced ACEX and obsolete Cyclone FPGA (40 MSps/15-bit of dynamic range). Huge progress in electronics and new challenges from physics impose a significant upgrade of the SD electronics either to improve a quality of measurements (much higher sampling and much wider dynamic range) or pick-up from a background extremely rare events (new FPGA algorithms based on sophisticated approaches like e.g. spectral triggers or neural networks). Much higher SD sensitivity is necessary to confirm or reject hypotheses critical for a modern astrophysics. The paper presents the Front-End Board (FEB) with the biggest Cyclone V E FPGA 5CEFA9F31I7N, supporting 8 channels sampled with max. 250 MSps @ 14-bit resolution. Considered sampling for the SD is 120 MSps, however, the FEB has been de...

  7. Spatial density profile of electrons near the LaAlO3/SrTiO3 heterointerface revealed by time-resolved photoluminescence spectroscopy

    International Nuclear Information System (INIS)

    The depth profile of the electron density near the LaAlO3/SrTiO3 heterointerface has been studied by means of time-resolved photoluminescence (PL) spectroscopy. A broad blue PL band is observed at 2.9 eV, originating from the two-carrier radiative recombination of interface-induced electrons and photoexcited holes. The PL lifetime of LaAlO3/SrTiO3 heterointerface is dominated by the three-carrier Auger recombination of electrons and holes and is sensitive to electron density. We tuned the probing depth by changing the excitation photon energy and evaluated the carrier-density profile using the relation between the carrier density and the PL lifetime. Our non-contact probe method based on PL spectroscopy indicates that the carriers are confined within several nanometers in depth near the LaAlO3/SrTiO3 heterostructures

  8. Two-Dimensional Electronic Spectroscopy Using Incoherent Light: Theoretical Analysis

    CERN Document Server

    Turner, Daniel B; Sutor, Erika J; Hendrickson, Rebecca A; Gealy, M W; Ulness, Darin J

    2012-01-01

    Electronic energy transfer in photosynthesis occurs over a range of time scales and under a variety of intermolecular coupling conditions. Recent work has shown that electronic coupling between chromophores can lead to coherent oscillations in two-dimensional electronic spectroscopy measurements of pigment-protein complexes measured with femtosecond laser pulses. A persistent issue in the field is to reconcile the results of measurements performed using femtosecond laser pulses with physiological illumination conditions. Noisy-light spectroscopy can begin to address this question. In this work we present the theoretical analysis of incoherent two-dimensional electronic spectroscopy, I(4) 2D ES. Simulations reveal diagonal peaks, cross peaks, and coherent oscillations similar to those observed in femtosecond two-dimensional electronic spectroscopy experiments. The results also expose fundamental differences between the femtosecond-pulse and noisy-light techniques; the differences lead to new challenges and opp...

  9. Electron-probe microanalysis: x-ray spectroscopy

    International Nuclear Information System (INIS)

    The main principles on X-ray, energy and wave length dispersive spectroscopy are reviewed. In order to allow the choice of the best operating conditions, the importance of the regulation and control systems is underlined. Emission theory, X-rays nature and its interaction with matter and electrons in the matter is shown. The structure, operating procedures and necessary electronics (single channel - analysis chain) automatic-control system for the threshold-energies discrimination and the energy distribution visualization) associated to the wavelength dispersive spectroscopy are described. The focusing control, resolution, influence of chemical bonds and multilayer-structure monochromators relaled to wavelength dispersive spectroscopy are studied. Concerning the energy-dispersive spectroscopy, the detector, preamplifier, amplifier, analog-digital converter, as well as the utilization and control of the spectrometer are described. Problems and instrumental progress on energy-dispersive spectroscopy related to the electronic-noise control, charge collection and light-elements detection are discussed

  10. Titanium oxidation-reduction at low oxygen pressure under electron bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Brasca, R. [Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000AOM) Santa Fe (Argentina)]. E-mail: rbrasca@fiqus.unl.edu.ar; Passeggi, M.C.G. [Laboratorio de Superficies e Interfaces, INTEC - CONICET and Universidad Nacional del Litoral, Gueemes 3450 (S3000GLN) Santa Fe (Argentina); Ferron, J. [Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000AOM) Santa Fe (Argentina); Laboratorio de Superficies e Interfaces, INTEC - CONICET and Universidad Nacional del Litoral, Gueemes 3450 (S3000GLN) Santa Fe (Argentina)

    2006-12-05

    The effect of the electron bombardment on the first stages of the titanium oxidation process has been studied by means of Auger Electron Spectroscopy. Using Factor Analysis and the valence electron dependence behaviour of the titanium LMV Auger transition, we found that the process is strongly dependent on the oxygen pressure and electron current density. Depending on the irradiation conditions, films of different thickness and Ti oxidized states are obtained.

  11. Factor analysis of d(NE)/dE Auger electron spectra of AuCu alloys: surface composition during Ar + ion bombardment and oxidation

    International Nuclear Information System (INIS)

    Factor analysis is applied to d(NE)/dE Auger electron spectra of a series of AuCu alloys (25% Au, 50% Au and 75% Au), including in the analysis the spectra of clean Au and Cu surfaces. Surface quantitation is obtained from the low-energy Au NOO and Cu LMM spectra of the alloys. The overlap of these spectra is resolved with factor analysis. An accuracy of the derived, relative surface concentrations of 1:100 is possible with this method, with a similar sensitivity to changes in surface composition. During Ar+ ion bombardment the surfaces of 25% and 50% Au alloys show no difference from the bulk concentrations, within ±1:100, from 1 to 3 keV Ar+ ion energy. For the 75% Au alloy, a slight Au enrichment is produced, when the energy increases from 1 to 3 keV. However, at 500 eV Ar+ ion energy, the surfaces become strongly enriched in Au, probably due to threshold effects for Au. Thus, no evidence for such strongly varying processes are found in molecular dynamics simulations of the mass effect in the sputtering process from a 50%:50% alloy. Factor analysis is also used to detect the presence of chemically affected spectral features during oxygen exposure at room temperature of the alloys and of pure Cu. Oxidation of the copper component is observed, producing at saturation a cuprous oxide with a total copper enrichment of the surface. (author)

  12. Electron-Transfer Acceleration Investigated by Time Resolved Infrared Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vlček Jr., Antonín; Kvapilová, Hana; Towrie, M.; Záliš, Stanislav

    2015-01-01

    Roč. 48, č. 3 (2015), s. 868-876. ISSN 0001-4842 Institutional support: RVO:61388955 Keywords : electron transfer * infrared spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 22.323, year: 2014

  13. Electron spectroscopy on high-temperature superconductors and related compounds

    International Nuclear Information System (INIS)

    In the last two classes of materials have been discovered which distinguish themselves due to a transition into the superconducting state at relatively high temperatures. These are the cuprate superconductors and the alkali metal doped fullerenes. In this work the electronic structure of representatives of these materials, undoped and Ca-doped YBa2Cu4O8 and A3C60 (A=K, Rb), has been investigated using electron energy-loss spectroscopy and photoemission spectroscopy. (orig.)

  14. Some applications of ballistic electron emission microscopy/spectroscopy

    International Nuclear Information System (INIS)

    A brief review of ballistic electron emission microscopy and spectroscopy applications is presented. Results of our ballistic electron emission spectroscopy measurements on cleaved n-GaAs are given. The threshold in ballistic current-voltage characteristic is observed at bias 1.93 V which is high above the expected threshold. Explanation of this effect is given in the frame of present theoretical results. (author)

  15. Observation of the Auger resonant Raman effect

    International Nuclear Information System (INIS)

    Monochromatized synchrotron radiation near the photoionization threshold was used to produce the [2p/sub 3/2/] vacancy state in atomic Xe. Deexcitation of the state through L3-M4M5(1G4) Auger-electron emission was measured. The 5d spectator-electron Auger satellite was observed. The satellite energy exhibits linear dispersion. The observed width of the 1G diagram line decreases by approx. 40% when the exciting photon energy reaches the vicinity of the Xe L3 binding energy. This radiationless process can thus be construed as the Auger analog of the x-ray resonant Raman effect. The 1G diagram line is shifted by -+3 eV due to post-collision interaction; this shift varies with excitation energy

  16. Far-Field Electron Spectroscopy of Nanoparticles

    OpenAIRE

    Itskovsky, M. A.; Cohen, H.; Maniv, T.

    2007-01-01

    A new type of excitations by highly focused electron beams in scanning transmission electron microscopes is predicted for nanoparticles. The calculated electron energy loss spectra of metallic (silver) and insulating (SiO(sub2)) nanoplatelets reveal dramatic enhancement of radiative electromagnetic modes within the light cone, allowed by the breakdown of momentum conservation in the inelastic scattering event. These modes can be accessed with e-beams in the vacuum far-field zone, similarly to...

  17. Double Auger Emission of fixed-in-space Carbon Monoxide following Core-Excitation and Ionization

    International Nuclear Information System (INIS)

    Double Auger decay after core-level photo excitation and after ionization through synchrotron radiation in gas phase carbon monoxide has been studied. We report the first experiment where both Auger electrons in double Auger decay have been measured in coincidence with the ionic fragments.

  18. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.

    2015-04-01

    It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.

  19. Diamond Analyzed by Secondary Electron Emission Spectroscopy

    Science.gov (United States)

    Krainsky, Isay L.

    1998-01-01

    Diamond is a promising semiconductor material for novel electronic applications because of its chemical stability and inertness, heat conduction properties, and so-called negative electron affinity (NEA). When a surface has NEA, electrons generated inside the bulk of the material are able to come out into the vacuum without any potential barrier (work function). Such a material would have an extremely high secondary electron emission coefficient o, very high photoelectron (quantum) yield, and would probably be an efficient field emitter. Chemical-vapor-deposited (CVD) polycrystalline diamond films have even more advantages than diamond single crystals. Their fabrication is relatively easy and inexpensive, and they can be grown with high levels of doping--consequently, they can have relatively high conductivity. Because of these properties, diamond can be used for cold cathodes and photocathodes in high-power electronics and in high-frequency and high-temperature semiconductor devices.

  20. Electron spectroscopy studies in heavy fermions

    International Nuclear Information System (INIS)

    Photoemission experiments (whereby an electron absorbs a packet of light energy and is able to escape from the host material due to its increased energy) can measure directly the energy distribution of electrons in various materials. Our measurements on a recently-discovered class of metallic materials called ''heavy fermions'' show that the electrons that actually carry the electric current in these metals exist only within an extremely narrow range of energies. This range, which we will call the bandwidth, is narrower than that found in ordinary metals like copper by at least a factor of 10. Indeed it is surprising that they can carry electric current at all since such narrow energy ranges (or band widths) are characteristic of electrons confined to their host atoms, as in a non-metal, rather than of electrons that are free to wander through a metal. 8 refs

  1. Electronic spectroscopy of transition metal dimer

    OpenAIRE

    Qian, Yue; 钱玥

    2013-01-01

    This thesis reports laser spectroscopic studies of gas-phase transition metal dimers using laser ablation/reaction with free jet expansion and laser-induced fluorescence (LIF) spectroscopy technique. Themolecules studied in this work are palladium dimer (Pd2) and vanadium dimer (V2). Many compounds formed from these transition metals are important and functional catalysts in chemical reactions. Therefore, it is of great significance to start from the fundamental level to understand the prope...

  2. Ballistic electron spectroscopy of semiconductor heterostructures

    International Nuclear Information System (INIS)

    A systematic study of electron transport through semiconductor superlattices in the transition region between coherent and scattering induced transport is performed. The measurements are carried out using a hot electron transistor as an electron spectrometer. A quasi monoenergetic, variable energy, ballistic hot electron beam is generated by a tunneling barrier injector and used to probe the intrinsic heterostructure transport properties as a function of a uniform electric field. Under flat band conditions the eigenstates of a periodic structure extend over the entire length of the superlattice forming minibands. From the measured transfer ratios, miniband positions and miniband widths are determined and compared to the results from self consistent calculations. The transmittance of the superlattice at different superlattice bias conditions is measured by varying the energy of the injected hot electron beam. For a superlattice longer than the coherence length, the transmission becomes asymmetric and dependent on the electric field direction. The onset of scattering induced miniband transport is clearly evident and the transition between coherent and incoherent electron transport in superlattices is observed for the first time. A coherence length of 150 nm and a scattering time of 1 ps is determined. The experimental result is in good agreement to a fully three dimensional calculation including interface roughness with typical island sizes of 10 mn. This clearly demonstrates that interface roughness scattering limits the coherence length of ballistic electrons in the superlattice. (author)

  3. Hydrocarbon isotope detection by elastic peak electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kostanovskiy, I.A., E-mail: kostanovskiyia@gmail.com [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Afanas’ev, V.P. [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Naujoks, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Mayer, M. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)

    2015-07-15

    Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses.

  4. Hydrocarbon isotope detection by elastic peak electron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses

  5. Single electron detection and spectroscopy via relativistic cyclotron radiation

    CERN Document Server

    Asner, D M; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thummler, T; VanDevender, B A; Woods, N L

    2014-01-01

    It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta sp...

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    A triphenylbromoethylene, 1,1-bis(p-hydroxyphenyl)-2-bromo-2-phenylethylene, Br-BHPE, and a bromosteroidal estrogen, 17α- bromovinylestradiol, BrVE2, were labeled with the Auger electron emitting nuclide bromine-80m, prepared by the [p,n] reaction with 80Se. 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 BrVE2 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 BrVE2 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

  8. Ultrafast Charge Transfer Visualized by Two-Dimensional Electronic Spectroscopy

    OpenAIRE

    Mančal T.; Milota F.; Hauer J; Christensson N.; Bixner O.; Lukeš V.; Kauffmann H. F.

    2013-01-01

    Two-dimensional electronic spectroscopy (2D-ES) is used to investigate ultrafast excited-state dynamics in a lutetium bisphthalocyanine dimer. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra. The combination of density matrix propagation and quantum chemical calculations results in a molecular view of the charge transfer dynamics and highlights the role of the counter-ion in providing an en...

  9. Secondary-electron cascade in attosecond photoelectron spectroscopy from metals

    DEFF Research Database (Denmark)

    Baggesen, Jan Conrad; Madsen, Lars Bojer

    an analytical model based on an approximate solution to Boltzmann's transport equation to account for the amount and energy distribution of these secondary electrons. Our theory is in good agreement with the electron spectrum found in a recent attosecond streaking experiment. To suppress the......Attosecond spectroscopy is currently restricted to photon energies around 100 eV. We show that under these conditions, electron-electron scatterings, as the photoelectrons leave the metal, give rise to a tail of secondary electrons with lower energies and hence a significant background. We develop...

  10. 核衰变产生的X射线和俄歇电子数据计算%Data Calculation of X-Ray and Auger Electron Arising from Nuclear Decay

    Institute of Scientific and Technical Information of China (English)

    周春梅; 黄小龙; 吴振东

    2003-01-01

    核衰变过程中,内转换电子发射和电子俘获能在原子电子壳层内留下空穴. 其他原子电子壳层的电子将填补这些空穴,其原子电子位置将重排,并发射X射线和俄歇电子. X射线和俄歇电子的能量由原子电子结合能计算得到,X射线和俄歇电子的强度分别由内转换电子发射和电子俘获在原子电子壳层内留下的空穴数,X射线荧光产额,和空穴转移系数计算得到. 本文简要介绍核衰变产生的X射线和俄歇电子数据的计算方法、计算程序与工作流程,并以核衰变为例说明其具体应用和简要讨论与总结.%In nuclear decay process, internal conversion electron emission and electron capture leave vacancies in atomic shells. The vacancies in atomic shells give rise to rearrangements in the shells which are accompanied by the emission of X-ray and the ejection of Auger electrons. The energies of X-ray and Auger electron can be calculated on the basis of atomic-electron binding energies in different atomic shells. The intensities of X-ray and Auger electron can be also calculated from vacancy number, X-ray fluorescence yield and vacancy transfer coefficient of different atomic shells. The calculation methods of energies and absolute intensities of X-ray and Auger electron arising from nuclear decay are introduced briefly. The calculation codes and flow chart are presented. The application is also given by using some nuclear decays as an example.

  11. Electronic structure of Pu carbides: photoelectron spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Gouder, T.; Havela, L.; Shick, Alexander; Huber, F.

    2008-01-01

    Roč. 403, č. 5-9 (2008), s. 852-853. ISSN 0921-4526 R&D Projects: GA AV ČR(CZ) IAA100100530 Grant ostatní: EU(XE) RITA-CT-2006-026176 Institutional research plan: CEZ:AV0Z10100520 Keywords : photoemission * electronic structure * plutonium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.822, year: 2008

  12. Electron cyclotron emission spectroscopy on thermonuclear plasmas

    International Nuclear Information System (INIS)

    Analysis of electron cyclotron emission (ECE) enables one to infer the radial profile of the electron temperature in tokamaks. The Dutch FOM institute for plasma physics has designed, built, installed and operated a grating polychromator for ECE measurements at JET. This thesis deals with a few instrumental aspects of this project and with applications of ECE measurements in tokamak physics studies. Ch. 3 and 4 deal with the wave transport in ECE systems. In Ch. 3 a method is developed to infer the mode conversion, which is a source for transmission losses, in a waveguide component from the antenna pattern of its exit aperture. In Ch. 4 the design and manufacture of the waveguide transition system to the grating polychromator are described. In Ch. 5 a method is reported for calibration of the spectrometers, based on the use of a microwave source which simulates a large area blackbody of very high temperature. The feasibility of the method is tested by applying it to two different ECE systems. In Ch. 6 a study of heat pulse propagation in tokamak plasma's, based on measurement of the electron temperature with the grating polychromator, is presented. 105 refs.; 48 figs.; 8 tabs

  13. Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy

    International Nuclear Information System (INIS)

    Here, we present a measurement platform for collecting multiple types of spectroscopy data during high-resolution environmental transmission electron microscopy observations of dynamic processes. Such coupled measurements are made possible by a broadband, high-efficiency, free-space optical system. The critical element of the system is a parabolic mirror, inserted using an independent hollow rod and placed below the sample holder which can focus a light on the sample and/or collect the optical response. We demonstrate the versatility of this optical setup by using it to combine in situ atomic-scale electron microscopy observations with Raman spectroscopy. The Raman data is also used to measure the local temperature of the observed sample area. Other applications include, but are not limited to: cathodo- and photoluminescence spectroscopy, and use of the laser as a local, high-rate heating source. - Highlights: • Broadband, high-efficiency design adaptable to other electron microscopes. • Raman spectroscopy integrated with environmental transmission electron microscopy. • Raman spectra peak frequency shifts enable measurement of local sample temperature. • Multiple types of optical spectroscopy enabled, e.g. cathodoluminescence

  14. Spectroscopy of nonequilibrium electrons and phonons

    CERN Document Server

    Shank, CV

    1992-01-01

    The physics of nonequilibrium electrons and phonons in semiconductors is an important branch of fundamental physics that has many practical applications, especially in the development of ultrafast and ultrasmall semiconductor devices. This volume is devoted to different trends in the field which are presently at the forefront of research. Special attention is paid to the ultrafast relaxation processes in bulk semiconductors and two-dimensional semiconductor structures, and to their study by different spectroscopic methods, both pulsed and steady-state. The evolution of energy and space distrib

  15. Electron Effective-Attenuation-Length Database

    Science.gov (United States)

    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).

  16. Pulse-shaping assisted multidimensional coherent electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Yuseff; Frei, Franziska; Cannizzo, Andrea, E-mail: andrea.cannizzo@iap.unibe.ch; Feurer, Thomas [Institute of Applied Physics, University of Bern, Sidlerstasse 5, CH-3012 Bern (Switzerland)

    2015-06-07

    Understanding nuclear and electronic dynamics of molecular systems has advanced considerably by probing their nonlinear responses with a suitable sequence of pulses. Moreover, the ability to control crucial parameters of the excitation pulses, such as duration, sequence, frequency, polarization, slowly varying envelope, or carrier phase, has led to a variety of advanced time-resolved spectroscopic methodologies. Recently, two-dimensional electronic spectroscopy with ultrashort pulses has become a more and more popular tool since it allows to obtain information on energy and coherence transfer phenomena, line broadening mechanisms, or the presence of quantum coherences in molecular complexes. Here, we present a high fidelity two-dimensional electronic spectroscopy setup designed for molecular systems in solution. It incorporates the versatility of pulse-shaping methods to achieve full control on the amplitude and phase of the individual exciting and probing pulses. Selective and precise amplitude- and phase-modulation is shown and applied to investigate electronic dynamics in several reference molecular systems.

  17. Pulse-shaping assisted multidimensional coherent electronic spectroscopy

    International Nuclear Information System (INIS)

    Understanding nuclear and electronic dynamics of molecular systems has advanced considerably by probing their nonlinear responses with a suitable sequence of pulses. Moreover, the ability to control crucial parameters of the excitation pulses, such as duration, sequence, frequency, polarization, slowly varying envelope, or carrier phase, has led to a variety of advanced time-resolved spectroscopic methodologies. Recently, two-dimensional electronic spectroscopy with ultrashort pulses has become a more and more popular tool since it allows to obtain information on energy and coherence transfer phenomena, line broadening mechanisms, or the presence of quantum coherences in molecular complexes. Here, we present a high fidelity two-dimensional electronic spectroscopy setup designed for molecular systems in solution. It incorporates the versatility of pulse-shaping methods to achieve full control on the amplitude and phase of the individual exciting and probing pulses. Selective and precise amplitude- and phase-modulation is shown and applied to investigate electronic dynamics in several reference molecular systems

  18. Electron-phonon scattering in molecular electronics: from inelastic electron tunnelling spectroscopy to heating effects

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Alessio; Frauenheim, Thomas; Niehaus, Thomas A [Bremen Center for Computational Materials Science, University of Bremen, D-28359 Bremen (Germany); Romano, Giuseppe; Pecchia, Alessandro; Di Carlo, Aldo [CNR-INFM Department of Electronics Engineering, University of Rome ' Tor Vergata' , Via del Politecnico 1, 00133 Rome (Italy)], E-mail: gagliard@bccms.uni-bremen.de, E-mail: Gagliardi@Ing.uniroma2.it

    2008-06-15

    In this paper, we investigate dissipation in molecular electronic devices. Dissipation is a crucial quantity which determines the stability and heating of the junction. Moreover, several experimental techniques which use inelastically scattered electrons as probes to investigate the geometry in the junction are becoming fundamental in the field. In order to describe such physical effects, a non-equilibrium Green's function (NEGF) method was implemented to include scattering events between electrons and molecular vibrations in current simulations. It is well known that the final heating of the molecule depends also on the ability of the molecule to relax vibrational quanta into the contact reservoirs. A semi-classical rate equation has been implemented and integrated within the NEGF formalism to include this relaxation. The model is based on two quantities: (i) the rate of emission of phonons in the junction by electron-phonon scattering and (ii) a microscopic approach for the computation of the phonon decay rate, accounting for the dynamical coupling between the vibrational modes localized on the molecule and the contact phonons. The method is applied to investigate inelastic electron tunnelling spectroscopy (IETS) signals in CO molecules on Cu(110) substrates as well as dissipation in C{sub 60} molecules on Cu(110) and Si(100) surfaces. It is found that the mechanisms of energy relaxation are highly mode-specific and depend crucially on the lead electronic structure and junction geometry.

  19. Electron-phonon scattering in molecular electronics: from inelastic electron tunnelling spectroscopy to heating effects

    International Nuclear Information System (INIS)

    In this paper, we investigate dissipation in molecular electronic devices. Dissipation is a crucial quantity which determines the stability and heating of the junction. Moreover, several experimental techniques which use inelastically scattered electrons as probes to investigate the geometry in the junction are becoming fundamental in the field. In order to describe such physical effects, a non-equilibrium Green's function (NEGF) method was implemented to include scattering events between electrons and molecular vibrations in current simulations. It is well known that the final heating of the molecule depends also on the ability of the molecule to relax vibrational quanta into the contact reservoirs. A semi-classical rate equation has been implemented and integrated within the NEGF formalism to include this relaxation. The model is based on two quantities: (i) the rate of emission of phonons in the junction by electron-phonon scattering and (ii) a microscopic approach for the computation of the phonon decay rate, accounting for the dynamical coupling between the vibrational modes localized on the molecule and the contact phonons. The method is applied to investigate inelastic electron tunnelling spectroscopy (IETS) signals in CO molecules on Cu(110) substrates as well as dissipation in C60 molecules on Cu(110) and Si(100) surfaces. It is found that the mechanisms of energy relaxation are highly mode-specific and depend crucially on the lead electronic structure and junction geometry

  20. Electron energy-loss spectroscopy of free fullerenes

    International Nuclear Information System (INIS)

    Pure samples of C60 and C70 were analyzed using electron energy loss spectroscopy (EELS). By varying the energy of the primary electrons optically allowed transitions could be distinguished from optically forbidden ones and from collective excitations. The collective excitation lines of C60 could be assigned to dipole and monopole excitations. The EEL-spectra of C70 exhibited a splitting of the plasmon excitation which is attributed to the non-sperical shape of the C70 molecule. (orig.)

  1. Scanning Tunneling Spectroscopy on Electron-Boson Interactions in Superconductors

    OpenAIRE

    Schackert, Michael Peter

    2014-01-01

    This thesis describes the experimental study of electron-boson interactions in superconductors by means of inelastic electron tunneling spectroscopy performed with a scanning tunneling microscope (STM) at temperatures below 1 K. This new approach allows the direct measurement of the Eliashberg function of conventional superconductors as demonstrated on lead (Pb) and niobium (Nb). Preparative experiments on unconventional iron-pnictides are presented in the end.

  2. Scanning tunneling spectroscopy on electron-boson interactions in superconductors

    CERN Document Server

    Schackert, Michael Peter

    2015-01-01

    This work describes the experimental study of electron-boson interactions in superconductors by means of inelastic electron tunneling spectroscopy performed with a scanning tunneling microscope (STM) at temperatures below 1 K. This new approach allows the direct measurement of the Eliashberg function of conventional superconductors as demonstrated on lead (Pb) and niobium (Nb). Preparative experiments on unconventional iron-pnictides are presented in the end.

  3. Electron Spectroscopy: Ultraviolet and X-Ray Excitation.

    Science.gov (United States)

    Baker, A. D.; And Others

    1980-01-01

    Reviews recent growth in electron spectroscopy (54 papers cited). Emphasizes advances in instrumentation and interpretation (52); photoionization, cross-sections and angular distributions (22); studies of atoms and small molecules (35); transition, lanthanide and actinide metal complexes (50); organometallic (12) and inorganic compounds (2);…

  4. On the merits of conversion electron Mossbauer spectroscopy in geosciences

    DEFF Research Database (Denmark)

    Gunnlaugsson, H.P.; Bertelsen, P.; Budtz-Jørgensen, Carl;

    2006-01-01

    Described are some applications of conversion electron Mossbauer spectroscopy (CEMS) in geosciences. It is shown how easily this technique can be applied in existing Mossbauer laboratories to investigate natural samples. Some examples demonstrate the kind of information CEMS can give on the...

  5. Auger emission from solid surfaces bombarded with ions

    International Nuclear Information System (INIS)

    The Auger electron emission from Be, Na, Mg, Al and Si bombarded with 0,5-20 KeV noble gas ions is studied. Sharp structures of the Auger electron spectra of Na and Be were identified. A Monte Carlo program was adapted to simulate the colision cascade in the solid, inner shell excitations and Auger decays. From the comparision of experimental and simulated Auger intensities, the relative role of symmetric and asymmetric collisions in Be K- and Al L-shell excitation were evaluated. In the case of Be, the discussion of the exciting processes to higher projectile energies was extended. To this end, the simulation to early measurements of Be K X-ray yields was applied. From this analysis, information about the variations of the fluorescence yield and outer-shell occupation numbers of Be with projectile energy was obtained. The study of the shape of the sharp Auger structures and their dependence with the energy and incidence projectile angle gives information about the collisional processes, inner hole lifetimes and Auger decays. From the evaluation of the energy and angular distribution of the excited sputtered atoms and the interaction between them and the metallic-surface, the energy shift distributions in the Auger energies were obtained. From the comparison of these distributions with the experimental atomic peaks, the main causes of the broadening of these peaks were determined. (M.E.L.)

  6. High-Resolution Conversion Electron Spectroscopy of Valence Electron Configurations (CESVEC) in Solids

    CERN Multimedia

    2002-01-01

    First measurements with the Zurich $\\beta$-spectrometer on sources from ISOLDE have demonstrated that high resolution spectroscopy of conversion electrons from valence shells is feasible.\\\\ \\\\ This makes possible a novel type of electron spectroscopy (CESVEC) on valence-electron configurations of tracer elements in solids. Thus the density of occupied electron states of impurities in solids has been measured for the first time. Such data constitute a stringent test of state-of-the-art calculations of impurity properties. Based on these results, we are conducting a systematic investigation of impurities in group IV and III-V semiconductors.

  7. Electron coincidence spectroscopy - an introduction to momentum space chemistry

    International Nuclear Information System (INIS)

    The application of electron coincidence spectroscopy or (e,2e) to obtaining detailed information on the dynamic structure of atoms and molecules is discussed. The technique obtains separation energy spectra and spherically averaged electron momentum distributions for each molecular orbital in the valence region. A brief discussion of molecular orbital density functions in momentum space is given. The results using Hartree-Fock wave functions for atomic orbitals and LCAO-MO-SCF wave functions for molecular orbitals are compared with (e,2e) data. The sensitivity of the data to electron correlations in either the initial or final ion many body states is discussed and examples given

  8. Ultrafast Charge Transfer Visualized by Two-Dimensional Electronic Spectroscopy

    Directory of Open Access Journals (Sweden)

    Mančal T.

    2013-03-01

    Full Text Available Two-dimensional electronic spectroscopy (2D-ES is used to investigate ultrafast excited-state dynamics in a lutetium bisphthalocyanine dimer. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra. The combination of density matrix propagation and quantum chemical calculations results in a molecular view of the charge transfer dynamics and highlights the role of the counter-ion in providing an energetic perturbation which promotes charge transfer across the complex.

  9. Study of Pd--Ta on Si(100) using Auger electron spectroscopy, Rutherford backscattering spectrometry, and variable energy positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    van der Kolk, G.J.; Kuiper, A.E.T.; Duchateau, J.P.W.B.; Willemsen, M.; Nielsen, B.; Lynn, K.G.

    1989-05-01

    The applicability of Pd/sub x/Ta/sub 1-//sub x/ as a diffusion barrier on Si has been investigated. For this purpose Pd/sub x/Ta/sub 1-//sub x/ films of 200-nm thickness (x ranges from 0 to 1) were deposited on Si(100), and the reaction between overlayer and substrate was studied as a function of temperature. Interaction was found to occur at temperatures increasing with the Ta content. The as-deposited Pd/sub x/Ta/sub 1-//sub x/ films with 0.2less than or equal toxless than or equal to0.6 were found to be amorphous. The amorphous phase had a higher reaction temperature than the crystalline one, causing a discontinuous step in the reaction temperature. Rutherford backscattering spectrometry spectra revealed that for the Pd-rich compositions, first a stoichiometric Pd/sub 2/Si layer formed underneath a pure Ta layer. At higher temperatures TaSi/sub 2/ formed at the surface. For Ta-rich compositions Pd/sub 2/Si formed first as well; however, the reaction temperature was so high that Pd/sub 2/Si grains formed in a Si matrix. The defect density of the Ta layer, which remained after outdiffusion of Pd, was investigated using variable energy positron annihilation. The defect concentration is very high, as deduced from the trapped positron fraction. A model is presented that describes the composition dependence of the reaction temperature.

  10. Vertically reciprocating auger

    Science.gov (United States)

    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.

  11. Using augers to extract minerals

    Energy Technology Data Exchange (ETDEWEB)

    Levkovich, P.Ye.; Meznikov, V.I.; Savich, N.S.

    1981-08-25

    The purpose of the device is to increase productivity based on eliminating empty auger trips. Following drilling the length of the auger away from the (preparatory) working area, the auger section is put in place on the side opposite from the drilled part of the (preparatory) working area. Simultaneous with drilling the other shaft opposite to the preparatory working area, the spindle device for injecting the bit into the drilled out part is set in place. Through it the auger sections are extracted from both shafts (facing each other) directly by moving the spindle device from one shaft to the other.

  12. Vibrational photodetachment spectroscopy near the electron affinity of S2

    Science.gov (United States)

    Barrick, J. B.; Yukich, J. N.

    2016-02-01

    We have conducted laser photodetachment spectroscopy near the detachment threshold of the electron affinity of S2 in a 1.8-T field. The ions are prepared by dissociative electron attachment to carbonyl sulfide. The experiment is conducted in a Penning ion trap and with a narrow-band, tunable, Ti:sapphire laser. A hybrid model for photodetachment in an ion trap is fit to the data using the appropriate Franck-Condon factors. The observations reveal detachment from and to the first few vibrational levels of the anion and the neutral molecule, respectively. Evaporative cooling of the anion ensemble condenses the thermal distribution to the lowest initial vibrational states. The subsequent detachment spectroscopy yields results consistent with a vibrationally cooled anion population.

  13. Communication: Investigation of the electron momentum density distribution of nanodiamonds by electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhenbao; Yang, Bing; Lin, Yangming; Su, Dangsheng, E-mail: dssu@imr.ac.cn [Shenyang National Laboratory of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016 (China)

    2015-12-07

    The electron momentum distribution of detonation nanodiamonds (DND) was investigated by recording electron energy-loss spectra at large momentum transfer in the transmission electron microscope (TEM), which is known as electron Compton scattering from solid (ECOSS). Compton profile of diamond film obtained by ECOSS was found in good agreement with prior photon experimental measurement and theoretical calculation that for bulk diamond. Compared to the diamond film, the valence Compton profile of DND was found to be narrower, which indicates a more delocalization of the ground-state charge density for the latter. Combining with other TEM characterizations such as high-resolution transmission electron spectroscopy, diffraction, and energy dispersive X-ray spectroscopy measurements, ECOSS was shown to be a great potential technique to study ground-state electronic properties of nanomaterials.

  14. Communication: Investigation of the electron momentum density distribution of nanodiamonds by electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    The electron momentum distribution of detonation nanodiamonds (DND) was investigated by recording electron energy-loss spectra at large momentum transfer in the transmission electron microscope (TEM), which is known as electron Compton scattering from solid (ECOSS). Compton profile of diamond film obtained by ECOSS was found in good agreement with prior photon experimental measurement and theoretical calculation that for bulk diamond. Compared to the diamond film, the valence Compton profile of DND was found to be narrower, which indicates a more delocalization of the ground-state charge density for the latter. Combining with other TEM characterizations such as high-resolution transmission electron spectroscopy, diffraction, and energy dispersive X-ray spectroscopy measurements, ECOSS was shown to be a great potential technique to study ground-state electronic properties of nanomaterials

  15. Inelastic electron tunneling spectroscopy of molecular transport junctions

    International Nuclear Information System (INIS)

    Inelastic electron tunneling spectroscopy (IETS) has become a premier analytical tool in the investigation of nano scale and molecular junctions. The IETS spectrum provides invaluable information about the structure, bonding, and orientation of component molecules in the junctions. One of the major advantages of IETS is its sensitivity and resolution at the level of single molecules. This review discusses how IETS is used to study molecular transport junctions and presents an overview of recent experimental studies.

  16. Exploring the potential of two-dimensional electronic spectroscopy

    International Nuclear Information System (INIS)

    During the last decade multi-dimensional ultrafast spectroscopies have shown great potential by opening an increasingly broad experimental window into the structure and dynamics of atomic and molecular systems on femtosecond and picosecond timescales. The versatility and significance of two-dimensional electronic spectroscopy relies on the gain of additional information obtained by spreading the spectra into two frequency dimensions. The present work summarizes part of our efforts in the field of two-dimensional electronic spectroscopy. The progress thereby ran parallel on two tracks: on the one hand, improvements in the instrumentation have led to a broader applicability of the method. By implementing a compact, easy to align, and passively phasestabilized setup for recording two-dimensional electronic spectra in three different phase-matching directions, it has become possible to study not only single-quantum but also double-quantum coherences. On the other hand, the existing methods have been applied to study the electronic and vibronic dynamics of molecular systems of varying complexity. An electronic two-level system whose electronic transition is coupled to a low-frequency vibrational mode has served as a starting point in our investigations. The vibronic wave packet that is induced by excitation with a femtosecond laser pulse manifests itself in oscillating line-shapes in the two-dimensional spectra. In a second step, the line-shape dynamics of a monomer-dimer system in equilibrium have been investigated. It was found that exciton delocalization effects in the dimer strongly influence the timescale of spectral diffusion. The degree of complexity reached its maximum in the investigation of pathways and timescales of energy transfer in double-wall cylindrical J-aggregates. Exciton dynamics in these molecular nanotubes have been characterized by temporal, energetic, and spatial properties. In addition, the double-exciton manifold of C8S3 aggregates has been

  17. Probing Battery Chemistry with Liquid Cell Electron Energy Loss Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Unocic, Raymond R.; Baggetto, Loic; Veith, Gabriel M.; Aguiar, Jeffery A.; Unocic, Kinga A.; Sacci, Robert L.; Dudney, Nancy J.; More, Karren L.

    2015-11-25

    We demonstrate the ability to apply electron energy loss spectroscopy (EELS) to follow the chemistry and oxidation states of LiMn2O4 and Li4Ti5O12 battery electrodes within a battery solvent. The use and importance of in situ electrochemical cells coupled with a scanning/transmission electron microscope (S/TEM) has expanded and been applied to follow changes in battery chemistry during electrochemical cycling. Furthermore, we discuss experimental parameters that influence measurement sensitivity and provide a framework to apply this important analytical method to future in situ electrochemical studies.

  18. In Situ Electron Energy Loss Spectroscopy in Liquids

    CERN Document Server

    Holtz, Megan E; Gao, Jie; Abruña, Héctor D; Muller, David A

    2012-01-01

    In situ scanning transmission electron microscopy (STEM) through liquids is a promising approach for exploring biological and materials processes. However, options for in situ chemical identification are limited: X-ray analysis is precluded because the holder shadows the detector, and electron energy loss spectroscopy (EELS) is degraded by multiple scattering events in thick layers. Here, we explore the limits of EELS for studying chemical reactions in their native environments in real time and on the nanometer scale. The determination of the local electron density, optical gap and thickness of the liquid layer by valence EELS is demonstrated for liquids. By comparing theoretical and experimental plasmon energies, we find that liquids appear to follow the free-electron model that has been previously established for solids. Signals at energies below the optical gap and plasmon energy of the liquid provide a high signal-to-background ratio as demonstrated for LiFePO4 in aqueous solution. The potential for using...

  19. An apparatus for picosecond electron pulse irradiation and optical spectroscopy

    International Nuclear Information System (INIS)

    A compact apparatus for time-resolved absorption spectroscopy is under development, using a photocathode RF electron gun. The apparatus can produce electron pulses with the energy of 3.7 MeV and with the width of 5 ps. Fast phenomena induced by the pulse will be investigated by photo-absorption method in this apparatus. The analyzing light pulses are supplied through optical parametric generation system excited by a picosecond Nd:YLF laser. The covered wavelength range and the pulse width will be 210 to 2000 nm and 10 ps, respectively. Time-dependent behaviors of transient species produced by electron pulses are to be followed by pump/probe method (or stroboscopic method) in which the electron pulse and the light pulse is temporally controlled by phase-shifting of RF fed into the laser with respect of RF for the gun. The time resolution of the measurement is estimated to be about 10 ps. (author)

  20. Inexpensive read-out for coincident electron spectroscopy with a transmission electron microscope at nanometer scale using micro channel plates and multistrip anodes

    International Nuclear Information System (INIS)

    The elemental composition of a sample at nanometer scale is determined by measurement of the characteristic energy of Auger electrons, emitted in coincidence with incoming primary electrons from a microbeam in a scanning transmission electron microscope (STEM). Single electrons are detected with position sensitive detectors, consisting of MicroChannel Plates (MCP) and MultiStrip Anodes (MSA), one for the energy of the Auger electrons (Auger-detector) and one for the energy loss of primary electrons (EELS-detector). The MSAs are sensed with LeCroy 2735DC preamplifiers. The fast readout is based on LeCroy's PCOS III system. On the detection of a coincidence (Event) energy data of Auger and EELS are combined with timing data to an Event word. Event words are stored in list mode in a VME memory module. Blocks of Event words are scanned by transputers in VME and two-dimensional energy histograms are filled using the timing information to obtain a maximal true/accidental ratio. The resulting histograms are stored on disk of a PC-386, which also controls data taking. The system is designed to handle 105 Events per second, 90% of which are accidental. In the histograms the ''true'' to ''accidental'' ratio will be 5. The dead time is 15%. ((orig.))

  1. DNA Electronic Fingerprints by Local Spectroscopy on Graphene

    Science.gov (United States)

    Balatsky, Alexander

    2013-03-01

    Working and scalable alternatives to the conventional chemical methods of DNA sequencing that are based on electronic/ionic signatures would revolutionize the field of sequencing. The approach of a single molecule imaging and spectroscopy with unprecedented resolution, achieved by Scanning Tunneling Spectroscopy (STS) and nanopore electronics could enable this revolution. We use the data from our group and others in applying this local scanning tunneling microscopy and illustrate possibilities of electronic sequencing of freeze dried deposits on graphene. We will present two types of calculated fingerprints: first in Local Density of States (LDOS) of DNA nucleotide bases (A,C,G,T) deposited on graphene. Significant base-dependent features in the LDOS in an energy range within few eV of the Fermi level were found in our calculations. These features can serve as electronic fingerprints for the identification of individual bases in STS. In the second approach we present calculated base dependent electronic transverse conductance as DNA translocates through the graphene nanopore. Thus we argue that the fingerprints of DNA-graphene hybrid structures may provide an alternative route to DNA sequencing using STS. Work supported by US DOE, NORDITA.

  2. The Pierre Auger Observatory

    International Nuclear Information System (INIS)

    We present the scientific motivation, conceptual design and status of the P. Auger Observatory, a hybrid detector designed to measure both the longitudinal and the lateral profile of giant air-showers produced by cosmic-rays of energy above 1019 eV. Two ground arrays of water Cerenkov tanks overlooked by fluorescence detectors will cover an area of 3000 km2 each. They will be build in the Southern and Northern hemisphere to provide full sky coverage. The total aperture of 14000 km2sr will allow to study all observable aspects of cosmic rays from below 10 EeV up to arbitrarily high energies with an unprecedented accuracy

  3. Quantum dynamics and electronic spectroscopy within the framework of wavelets

    International Nuclear Information System (INIS)

    This paper serves as a first-time report on formulating important aspects of electronic spectroscopy and quantum dynamics in condensed harmonic systems using the framework of wavelets, and a stepping stone to our future work on developing anharmonic wavelets. The Morlet wavelet is taken to be the mother wavelet for the initial state of the system of interest. This work reports daughter wavelets that may be used to study spectroscopy and dynamics of harmonic systems. These wavelets are shown to arise naturally upon optical electronic transition of the system of interest. Natural birth of basis (daughter) wavelets emerging on exciting an electronic two-level system coupled, both linearly and quadratically, to harmonic phonons is discussed. It is shown that this takes place through using the unitary dilation and translation operators, which happen to be part of the time evolution operator of the final electronic state. The corresponding optical autocorrelation function and linear absorption spectra are calculated to test the applicability and correctness of the herein results. The link between basis wavelets and the Liouville space generating function is established. An anharmonic mother wavelet is also proposed in the case of anharmonic electron–phonon coupling. A brief description of deriving anharmonic wavelets and the corresponding anharmonic Liouville space generating function is explored. In conclusion, a mother wavelet (be it harmonic or anharmonic) which accounts for Duschinsky mixing is suggested. (paper)

  4. Interatomic Coulombic decay of NeAr dimers following Auger decay

    International Nuclear Information System (INIS)

    Using momentum-resolved electron-ion multicoincidence, we have investigated interatomic Coulombic decay (ICD). We observed ICD processes in NeAr dimers following Ar LMM and Ne KLL Auger decay. From Auger final state of Ar2+(3s−2), we observed ICD where three electrons participate in.

  5. Interfacial Electron Transfer and Transient Photoconductivity Studied with Terahertz Spectroscopy

    Science.gov (United States)

    Milot, Rebecca Lee

    Terahertz spectroscopy is distinguished from other far infrared and millimeter wave spectroscopies by its inherent phase sensitivity and sub-picosecond time resolution making it a versatile technique to study a wide range of physical phenomena. As THz spectroscopy is still a relatively new field, many aspects of THz generation mechanisms have not been fully examined. Using terahertz emission spectroscopy (TES), THz emission from ZnTe(110) was analyzed and found to be limited by two-photon absorption and free-carrier generation at high excitation fluences. Due to concerns about the continued use of fossil fuels, solar energy has been widely investigated as a promising source of renewable energy. Dye-sensitized solar cells (DSSCs) have been developed as a low-cost alternative to conventional photovoltaic solar cells. To solve the issues of the intermittency and inefficient transport associated with solar energy, researchers are attempting to adapt DSSCs for water oxidation and chemical fuel production. Both device designs incorporate sensitizer molecules covalently bound to metal oxide nanoparticles. The sensitizer, which is comprised of a chromophore and anchoring group, absorbs light and transfers an electron from its excited state to the conduction band of the metal oxide, producing an electric current. Using time-resolved THz spectroscopy (TRTS), an optical pump/THz probe technique, the efficiency and dynamics of electron injection from sensitizers to metal oxides was evaluated as a function of the chromophore, its anchoring group, and the metal oxide identity. Experiments for studying fully functioning DSSCs and water oxidation devices are also described. Bio-inspired pentafluorophenyl porphyrin chromophores have been designed and synthesized for use in photoelectrochemical water oxidation cells. Influences on the efficiency and dynamics of electron injection from the chromophores into TiO2 and SnO2 nanoparticles due to changes in both the central substituent to

  6. Probing Plasmonic Nanostructures with Electron Energy - Loss Spectroscopy

    DEFF Research Database (Denmark)

    Raza, Søren

    generalized nonlocal optical response model, which expands the hydrodynamic model by taking into account the diffusion of free electrons in metals through Fick’s law. We go on to consider the implications of these two nonlocal models in the following plasmonic geometries: metal-insulator interface, nanosphere...... nonlocal response. The experimental work comprises the use of electron energy-loss spectroscopy (EELS) to excite and study both localized and propagating surface plasmons in metal structures. Following a short introduction, we present the theoretical foundation to describe nonlocal response in Maxwell......-response approximation. Irrespective of the microscopic origin, we find that nonlocal response modifies the electromagnetic wave equation by an additional Laplacian term. The hydrodynamic model, which includes nonlocal response through the Thomas–Fermi pressure of a free-electron gas, is discussed. We present also the...

  7. Modeling ellipsometry and electron energy loss spectroscopy of graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, Keenan A.; Miskovic, Zoran L. [Department of Applied Mathematics, University of Waterloo, 200 University Ave W, N2L 3G1, Waterloo, Ontario (Canada); Diebold, Alain C. [College of Nanoscale Science and Engineering, State University of New York at Albany, 255 Fuller Rd., Albany, New York 12203 (United States); Idrobo, Juan-Carlos [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-03-31

    Recent studies of electronic excitations in graphene by Electron Energy Loss Spectroscopy (EELS) have revealed massive high-frequency peaks assigned to the π and σ+π plasmons [1], which were semi-quantitatively modeled with a two-dimensional, two-fluid hydrodynamic (HD) model [2]. On the other hand, Spectroscopic Ellipsometry (SE) of graphene covers the region of nearly constant absorbance due to graphene’s universal optical conductivity at infrared frequencies, which is not clearly resolved by EELS, and goes up to cover the π-plasmon peak at ultraviolet frequencies [3]. To attempt to model both the SE and EELS, we amend the HD model by including a low-frequency contribution of graphene’s inter-band transitions, while monitoring the fulfillment of the f-sum rule [4] up to frequencies that cover excitations of all valence electrons.

  8. Valence Electronic Structure of Aqueous Solutions: Insights from Photoelectron Spectroscopy

    Science.gov (United States)

    Seidel, Robert; Winter, Bernd; Bradforth, Stephen E.

    2016-05-01

    The valence orbital electron binding energies of water and of embedded solutes are crucial quantities for understanding chemical reactions taking place in aqueous solution, including oxidation/reduction, transition-metal coordination, and radiation chemistry. Their experimental determination based on liquid-photoelectron spectroscopy using soft X-rays is described, and we provide an overview of valence photoelectron spectroscopy studies reported to date. We discuss principal experimental aspects and several theoretical approaches to compute the measured binding energies of the least tightly bound molecular orbitals. Solutes studied are presented chronologically, from simple electrolytes, via transition-metal ion solutions and several organic and inorganic molecules, to biologically relevant molecules, including aqueous nucleotides and their components. In addition to the lowest vertical ionization energies, the measured valence photoelectron spectra also provide information on adiabatic ionization energies and reorganization energies for the oxidation (ionization) half-reaction. For solutes with low solubility, resonantly enhanced ionization provides a promising alternative pathway.

  9. Double Core-Hole Production in N2: Beating the Auger Clock

    International Nuclear Information System (INIS)

    We investigate the creation of double K-shell holes in N2 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.

  10. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  11. Chemical changes of titanium and titanium dioxide under electron bombardment

    OpenAIRE

    Romins Brasca; Luciana Ines Vergara; Mario César Guillermo Passeggi; Julio Ferrón

    2007-01-01

    The electron induced effect on the first stages of the titanium (Ti0) oxidation and titanium dioxide (Ti4+) chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+).

  12. Electronic structure of undoped and potassium doped coronene investigated by electron energy-loss spectroscopy

    OpenAIRE

    Roth, Friedrich; Bauer, Johannes; Mahns, Benjamin; Büchner, Bernd; Knupfer, Martin

    2012-01-01

    We performed electron energy-loss spectroscopy studies in transmission in order to obtain insight into the electronic properties of potassium intercalated coronene, a recently discovered superconductor with a rather high transition temperature of about 15\\,K. A comparison of the loss function of undoped and potassium intercalated coronene shows the appearance of several new peaks in the optical gap upon potassium addition. Furthermore, our core level excitation data clearly signal filling of ...

  13. Correlating the motion of electrons and nuclei with two-dimensional electronic-vibrational spectroscopy.

    Science.gov (United States)

    Oliver, Thomas A A; Lewis, Nicholas H C; Fleming, Graham R

    2014-07-15

    Multidimensional nonlinear spectroscopy, in the electronic and vibrational regimes, has reached maturity. To date, no experimental technique has combined the advantages of 2D electronic spectroscopy and 2D infrared spectroscopy, monitoring the evolution of the electronic and nuclear degrees of freedom simultaneously. The interplay and coupling between the electronic state and vibrational manifold is fundamental to understanding ensuing nonradiative pathways, especially those that involve conical intersections. We have developed a new experimental technique that is capable of correlating the electronic and vibrational degrees of freedom: 2D electronic-vibrational spectroscopy (2D-EV). We apply this new technique to the study of the 4-(di-cyanomethylene)-2-methyl-6-p-(dimethylamino)styryl-4H-pyran (DCM) laser dye in deuterated dimethyl sulfoxide and its excited state relaxation pathways. From 2D-EV spectra, we elucidate a ballistic mechanism on the excited state potential energy surface whereby molecules are almost instantaneously projected uphill in energy toward a transition state between locally excited and charge-transfer states, as evidenced by a rapid blue shift on the electronic axis of our 2D-EV spectra. The change in minimum energy structure in this excited state nonradiative crossing is evident as the central frequency of a specific vibrational mode changes on a many-picoseconds timescale. The underlying electronic dynamics, which occur on the hundreds of femtoseconds timescale, drive the far slower ensuing nuclear motions on the excited state potential surface, and serve as a excellent illustration for the unprecedented detail that 2D-EV will afford to photochemical reaction dynamics. PMID:24927586

  14. Design of nuclear spectroscopy electronics based on the EUROsystem standard

    International Nuclear Information System (INIS)

    The development of modular nuclear instruments in the EUROcard system has been continued by the design of a staircase generator; such an instrument is needed for accurate testing of spectroscopy amplifiers. The generator provides very precisely defined steps with the period between them varying from 8 to 50 microseconds, the output voltage continuously variable from 2 to 5 V, and attenuated ion steps between 1 and 100. Great care was taken that individual steps exhibit no overshot, thus providing a very clean signal to the input of a tested amplifier. The circuitry is kept simple, and it can be easily constructed in any electronics laboratory. Figs

  15. Tomography of Particle Plasmon Fields from Electron Energy Loss Spectroscopy

    Science.gov (United States)

    Hörl, Anton; Trügler, Andreas; Hohenester, Ulrich

    2013-08-01

    We theoretically investigate electron energy loss spectroscopy (EELS) of metallic nanoparticles in the optical frequency domain. Using a quasistatic approximation scheme together with a plasmon eigenmode expansion, we show that EELS can be rephrased in terms of a tomography problem. For selected single and coupled nanoparticles we extract the three-dimensional plasmon fields from a collection of rotated EELS maps. Our results pave the way for a fully three-dimensional plasmon-field tomography and establish EELS as a quantitative measurement device for plasmonics.

  16. Probing Nanoscale Electronic and Magnetic Interaction with Scanning Tunneling Spectroscopy

    DEFF Research Database (Denmark)

    Bork, Jakob

    tunneling microscope (STM). Especially at low temperatures the Kondo resonance is used to probe magnetic interaction with ferromagnetic islands and between two atoms. The latter showing a crossover between Kondo screened atoms and antiferromagnetically coupled atoms close to the quantum critical point. This...... is related to research in correlated electron materials such as studies of phase transitions in heavy fermion compounds and magnetic interaction in spintronic research. The capping of cobalt islands on Cu(111) with silver is investigated with STM and photoemission spectroscopy. It is shown that at...

  17. Ultrafast Spectroscopy of Delocalized Excited States of the Hydrated Electron

    International Nuclear Information System (INIS)

    Research under support of this grant has been focused on the understanding of highly delocalized ''conduction-band-like'' excited states of solvated electrons in bulk water, in water trapped in the core of reverse micelles, and in alkane solvents. We have strived in this work to probe conduction-band-like states by a variety of ultrafast spectroscopy techniques. (Most of which were developed under DOE support in a previous funding cycle.) We have recorded the optical spectrum of the hydrated electron for the first time. This was accomplished by applying a photo-detrapping technique that we had developed in a previous funding cycle, but had not yet been applied to characterize the actual spectrum. In the cases of reverse micelles, we have been investigating the potential role of conduction bands in the electron attachment process and the photoinduced detrapping, and have published two papers on this topic. Finally, we have been exploring solvated electrons in isooctane from various perspectives. All of these results strongly support the conclusion that optically accessible, highly delocalized electronic states exist in these various media

  18. In situ electron energy-loss spectroscopy in liquids.

    Science.gov (United States)

    Holtz, Megan E; Yu, Yingchao; Gao, Jie; Abruña, Héctor D; Muller, David A

    2013-08-01

    In situ scanning transmission electron microscopy (STEM) through liquids is a promising approach for exploring biological and materials processes. However, options for in situ chemical identification are limited: X-ray analysis is precluded because the liquid cell holder shadows the detector and electron energy-loss spectroscopy (EELS) is degraded by multiple scattering events in thick layers. Here, we explore the limits of EELS in the study of chemical reactions in their native environments in real time and on the nanometer scale. The determination of the local electron density, optical gap, and thickness of the liquid layer by valence EELS is demonstrated. By comparing theoretical and experimental plasmon energies, we find that liquids appear to follow the free-electron model that has been previously established for solids. Signals at energies below the optical gap and plasmon energy of the liquid provide a high signal-to-background ratio regime as demonstrated for LiFePO4 in an aqueous solution. The potential for the use of valence EELS to understand in situ STEM reactions is demonstrated for beam-induced deposition of metallic copper: as copper clusters grow, EELS develops low-loss peaks corresponding to metallic copper. From these techniques, in situ imaging and valence EELS offer insights into the local electronic structure of nanoparticles and chemical reactions. PMID:23721691

  19. Auger electron emitter against multiple myeloma - targeted endo-radio-therapy with {sup 125}I-labeled thymidine analogue 5-iodo-4'-thio-2'-deoxyuridine

    Energy Technology Data Exchange (ETDEWEB)

    Morgenroth, Agnieszka, E-mail: amorgenroth@ukaachen.de [Nuclear Medicine Clinic, University Ulm, Albert-Einstein-Allee 23, D-89081 Ulm (Germany); Nuclear Medicine Clinic, University Aachen, RWTH, Pauwelsstrasse 30, D-52074 Aachen (Germany); Dinger, Cornelia; Zlatopolskiy, Boris D.; Al-Momani, Ehab; Glatting, Gerhard [Nuclear Medicine Clinic, University Ulm, Albert-Einstein-Allee 23, D-89081 Ulm (Germany); Mottaghy, Felix M. [Nuclear Medicine Clinic, University Aachen, RWTH, Pauwelsstrasse 30, D-52074 Aachen (Germany); Reske, Sven N. [Nuclear Medicine Clinic, University Ulm, Albert-Einstein-Allee 23, D-89081 Ulm (Germany)

    2011-10-15

    Introduction: Multiple myeloma (MM) is a plasma cell malignancy characterized by accumulation of malignant, terminally differentiated B cells in the bone marrow. Despite advances in therapy, MM remains an incurable disease. Novel therapeutic approaches are, therefore, urgently needed. Auger electron-emitting radiopharmaceuticals are attractive for targeted nano-irradiation therapy, given that DNA of malignant cells is selectively addressed. Here we evaluated the antimyeloma potential of the Auger electron-emitting thymidine analogue {sup 125}I-labeled 5-iodo-4'-thio-2'-deoxyuridine ([{sup 125}I]ITdU). Methods: Cellular uptake and DNA incorporation of [{sup 125}I]ITdU were determined in fluorodeoxyuridine-pretreated KMS12BM, U266, dexamethasone-sensitive MM1.S and -resistant MM1.R cell lines. The effect of stimulation with interleukin 6 (IL6) or insulin-like growth factor 1 (IGF1) on the intracellular incorporation of [{sup 125}I]ITdU was investigated in cytokine-sensitive MM1.S and MM1.R cell lines. Apoptotic cells were identified using Annexin V. Cleavage of caspase 3 and PARP was visualized by Western blot. DNA fragmentation was investigated using laddering assay. Therapeutic efficiency of [{sup 125}I]ITdU was proven by clonogenic assay. Results: [{sup 125}I]ITdU was shown to be efficiently incorporated into DNA of malignant cells, providing a promising mechanism for delivering highly toxic Auger radiation emitters into tumor DNA. [{sup 125}I]ITdU had a potent antimyeloma effect in cell lines representing distinct disease stages and, importantly, in cell lines sensitive or resistant to the conventional therapeutic agent, but was not toxic for normal plasma and bone marrow stromal cells. Furthermore, [{sup 125}I]ITdU abrogated the protective actions of IL6 and IGF1 on MM cells. [{sup 125}I]ITdU induced massive damage in the DNA of malignant plasma cells, which resulted in efficient inhibition of clonogenic growth. Conclusion: These studies may provide a

  20. Conversion electron spectroscopy of isobarically purified trapped radioactive ions

    International Nuclear Information System (INIS)

    The feasibility of the JYFLTRAP for in-trap spectroscopy has been studied. Several internally converted transitions have been measured for isomers of fission products with good accuracy. High-resolution spectroscopic data free of source effects have been obtained proving that trapped radioactive ions can provide excellent conversion electron sources. The shortest-lived isomer studied in this work was 117m Pd with a half-life of 19.1 ms, for which a superior peak-to-total ratio and an excellent line shape at the 9.9 keV conversion electron line have been observed. Detection efficiencies and related phenomena of the present setup are analyzed. (orig.)

  1. Angle resolved electron energy loss spectroscopy on graphite

    Science.gov (United States)

    Diebold, U.; Preisinger, A.; Schattschneider, P.; Varga, P.

    We report on angle resolved electron energy loss spectroscopy (EELS) in reflection mode with low primary energy on a graphite single crystal. Measurements with primary electron energy of 175 eV have been performed in off-Bragg-reflex geometry in two different directions within the (0001) surface plane of the graphite single crystal. In addition, EELS measurements in specular reflection mode with different primary energies and angles of incidence were done in order to distinguish between surface and bulk plasmon losses. The energy losses and the transferred momenta of the losses have been analyzed. The results are compared with the loss functions for bulk and surface excitations calculated from the dielectric function ɛ(ω, q) obtained from TEELS-data (EELS in transmission mode) [Springer Tracts Mod. Phys. 54 (1970) 77].

  2. Auger and SIMS spectrometry in microelectronics

    International Nuclear Information System (INIS)

    X-ray microanalysis limitations led to the development of analytical techniques more sensitive to the ''surface'' layer of the samples. The need for these methods arises from the importance of such layers in determining the characteristics of semiconductor devices. Two recent methods of surface analysis are described in this paper, namely the Auger Electron Spectrometry (AES) and the Secondary Ion Mass Spectrometry (SIMS). Various AES and SIMS spectrometers are already available on the market, and are currently used in R and D or production laboratories of the electronic industries

  3. ESCA [electron spectroscopy for chemical analysis] examination of metal oxides and electronic ceramic materials: The effect of a low-energy argon-ion beam

    International Nuclear Information System (INIS)

    Electronic ceramic materials are increasingly of interest to chemists because there is a growing interest in preparing high purity ceramics by chemical means and because the properties of the ceramics often depend on the chemical state of the elements in the ceramic. The chemical species, e.g. the oxidation state, of a metal in a ceramic can be identified by the analytical technique known as ESCA (electron spectroscopy for chemical analysis). In this work, the application of ESCA to ceramic materials begins with studies of metal oxide powders and examines the effect of a low energy argon ion beam. Two problems that occur with oxide powders and ceramics are surface charging and the formation of carbonates on the surface. Surface charging is generally compensated for by referencing to the carbon contaminant or by flooding the surface with electrons. Referencing to the contaminant peak meets with limited success when compared to the literature. Flooding the surface of oxide powders and ceramics causes peak distortion. Surface carbonates are identified in the carbon region by their separation of -4.5 eV from the contaminant carbon. To examine the effect of a low energy ion beam on metal oxide powders and ceramic powders, both the X-ray photoelectron (XPS) and X-ray induced Auger electron spectra (XAES) of SC2O3, V2O5, Cu2 O, ZnO and SnO2 are examined before and after ion beam exposure. Limited reduction of the metal is noted in the XPS spectra of V2O5. XAES indicates the Sc2O3, Cu2O and SnO2 are also reduced. XAES is especially useful for determining that reduction by the ion beam has occurred. A comparison of ion beam exposed oxide powders and heavily oxidized metal foils (Ti, Zr and Nb) shows that while the powders undergo limited reduction, the oxidized foils are reduced much more significantly with the same sputtering parameters

  4. Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

    International Nuclear Information System (INIS)

    Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions

  5. Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

    2015-05-07

    Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.

  6. Development of an (e,2e) electron momentum spectroscopy apparatus using an ultrashort pulsed electron gun

    International Nuclear Information System (INIS)

    An (e,2e) apparatus for electron momentum spectroscopy (EMS) has been developed, which employs an ultrashort-pulsed incident electron beam with a repetition rate of 5 kHz and a pulse duration in the order of a picosecond. Its instrumental design and technical details are reported, involving demonstration of a new method for finding time-zero. Furthermore, EMS data for the neutral Ne atom in the ground state measured by using the pulsed electron beam are presented to illustrate the potential abilities of the apparatus for ultrafast molecular dynamics, such as by combining EMS with the pump-and-probe technique.

  7. Auger radiation targeted into DNA: a therapy perspective

    International Nuclear Information System (INIS)

    Auger electron emitters that can be targeted into DNA of tumour cells represent an attractive systemic radiation therapy goal. In the situation of DNA-associated decay, the high linear energy transfer (LET) of Auger electrons gives a high relative biological efficacy similar to that of α particles. In contrast to α radiation, however, Auger radiation is of low toxicity when decaying outside the cell nucleus, as in cytoplasm or outside cells during blood transport. The challenge for such therapies is the requirement to target a high percentage of all cancer cells. An overview of Auger radiation therapy approaches of the past decade shows several research directions and various targeting vehicles. The latter include hormones, peptides, halogenated nucleotides, oligonucleotides and internalising antibodies. Here, we will discuss the basic principles of Auger electron therapy as compared with vector-guided α and β radiation. We also review some radioprotection issues and briefly present the main advantages and disadvantages of the different targeting modalities that are under investigation. (orig.)

  8. Nanogap structures: combining enhanced Raman spectroscopy and electronic transport.

    Science.gov (United States)

    Natelson, Douglas; Li, Yajing; Herzog, Joseph B

    2013-04-21

    Surface-enhanced Raman spectroscopy (SERS) is an experimental tool for accessing vibrational and chemical information, down to the single molecule level. SERS typically relies on plasmon excitations in metal nanostructures to concentrate the incident radiation and to provide an enhanced photon density of states to couple emitted radiation to the far field. Many common SERS platforms involve metal nanoparticles to generate the required electromagnetic enhancements. Here we concentrate on an alternative approach, in which the relevant plasmon excitations are supported at a truly nanoscale gap between extended electrodes, rather than discrete subwavelength nanoparticles. The ability to fabricate precise gaps on demand, and in some cases to tune the gap size in situ, combined with the additional capability of simultaneous electronic transport measurements of the nanogap, provides access to information not previously available in standard SERS. We summarize the rich plasmonic physics at work in these extended systems and highlight the recent state of the art including tip-enhanced Raman spectroscopy (TERS) and the application of mechanical break junctions and electromigrated junctions. We describe in detail how we have performed in situ gap-enhanced Raman measurements of molecular-scale junctions while simultaneously subjecting these structures to electronic transport. These extended electrode structures allow us to study the pumping of vibrational modes by the flow of tunneling electrons, as well as the shifting of vibrational energies due to the applied bias. These experiments extend SERS into a tool for examining fundamental processes of dissipation, and provide insight into the mechanisms behind SERS spectral diffusion. We conclude with a brief discussion of future directions. PMID:23385304

  9. Stochastic stimulated electronic x-ray Raman spectroscopy

    CERN Document Server

    Kimberg, Victor

    2015-01-01

    Resonant inelastic x-ray scattering (RIXS) is a well-established tool for studying electronic, nuclear and collective dynamics of excited atoms, molecules and solids. An extension of this powerful method to a time-resolved probe technique at x-ray free electron lasers (XFELs) to ultimately unravel ultrafast chemical and structural changes on a femtosecond time scale is often challenging, due to the small signal rate in conventional implementations at XFELs that rely on the usage of a monochromator set up to select a small frequency band of the broadband, spectrally incoherent XFEL radiation. Here, we suggest an alternative approach, based on stochastic spectroscopy, that uses the full bandwidth of the incoming XFEL pulses. Our proposed method is relying on stimulated resonant inelastic x-ray scattering, where in addition to a pump pulse that resonantly excites the system a probe pulse on a specific electronic inelastic transition is provided, that serves as seed in the stimulated scattering process. The limit...

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

    International Nuclear Information System (INIS)

    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 tecticular 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 partciles 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. (orig.)

  11. Gas flow counter conversion electron Moessbauer spectroscopy (GFC-CEMS)

    International Nuclear Information System (INIS)

    Conversion Electron Moessbauer Spectroscopy (CEMS) is well established technique to study surface properties of materials. However non availability of commercial experimental set up and complexity of operational parameters have been restricting the working experimental groups with in the country and abroad. In this paper we have presented the development work for the design of Gas Flow Counter (GFC), e.g. convenient sample mount, grounding, steady flow rate adjustment and minimum He-losses so that the detector operation and installation becomes convenient and dependable. The basic design is modified e.g. large volume to maintain steady gas flow, sample mount close to central wire and O-ring fitted flange. The CEMS spectra are recorded using conventional Moessbauer drive and 57Co source. The calibrated spectrum shows a detection efficiency of about 20% for natural iron and steel foil. The CEMS spectrum for FeTi bulk and transmission Moessbauer Spectroscopy (TMS) spectrum of FeTi thin film deposited by vacuum evaporation on thin glass substrate were recorded to test the performance of GFC-CEMS. (author)

  12. Electronic spectroscopy of organic semiconductors in helium nanodroplets

    Energy Technology Data Exchange (ETDEWEB)

    Dvorak, Matthieu; Buenermann, Oliver; Stienkemeier, Frank [Physikalisches Institut, Universitaet Freiburg (Germany); Eisfeld, Alexander [MPI-PKS, Dresden (Germany)

    2009-07-01

    Spectroscopy of molecules or molecular complexes embedded in helium nanodroplets is an outstanding tool to characterize electronic and geometric structures. Due to the unique properties of the superfluid droplets, helium nanodroplets isolation (HENDI) spectroscopy reaches far better spectral resolution than usually obtained in organic solvents or on thin films. We applied HENDI to investigate the absorption and emission spectra of the PTCDA molecule and its complexes. The PTCDA monomer shows sharp vibronic lines (<1 cm-1) that can be assigned to different internal vibration modes as well as overtones and combination modes. PTCDA complexes show different spectral features. Sharp lines, red shifted compared to the monomer absorptions are assigned to T-structured dimers. Additionally, very broad absorption lines are observed. These are assigned to complexes forming sandwich structures. Recent theoretical calculations can reproduce the spectra and support this interpretation. Furthermore, in comparison to absorption spectra, emission intensities allow to study the amount of internal relaxation before emitting a photon, giving further insight into the involved processes.

  13. Exploring the Single Atom Spin State by Electron Spectroscopy.

    Science.gov (United States)

    Lin, Yung-Chang; Teng, Po-Yuan; Chiu, Po-Wen; Suenaga, Kazu

    2015-11-13

    To control the spin state of an individual atom is an ultimate goal for spintronics. A single atom magnet, which may lead to a supercapacity memory device if realized, requires the high-spin state of an isolated individual atom. Here, we demonstrate the realization of well isolated transition metal (TM) atoms fixed at atomic defects sparsely dispersed in graphene. Core-level electron spectroscopy clearly reveals the high-spin state of the individual TM atoms at the divacancy or edge of the graphene layer. We also show for the first time that the spin state of single TM atoms systematically varies with the coordination of neighboring nitrogen or oxygen atoms. These structures can be thus regarded as the smallest components of spintronic devices with controlled magnetic behavior. PMID:26613462

  14. Identification of irradiated chicken meat using electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Studies were carried out on detection of irradiation treatment in chicken using electron spin resonance (ESR) spectroscopy. The effect of gamma- irradiation treatment on radiation induced signal in different types of chicken namely, broiler, deshi and layers was studied. Irradiation treatment induced a characteristic ESR signal that was not detected in non-irradiated samples. The shape of the signal was not affected by type of the bone. The intensity of radiation induced ESR signal was affected by factors such as absorbed radiation dose, bone type irradiation temperature, post-irradiation storage, post-irradiation cooking and age of the bird. Deep-frying resulted in the formation of a symmetric signal that had a different shape and was weaker than the radiation induced signal. This technique can be effectively used to detect irradiation treatment in bone-in chicken meat even if stored and/or subjected to various traditional cooking procedures. (author)

  15. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  16. Raman spectroscopy of fluoropolymer conformal coatings on electronic boards

    Science.gov (United States)

    Rodošek, Mirjana; Perše, Lidija Slemenik; Mihelčič, Mohor; Koželj, Matjaž; Orel, Boris; Bengű, Başak; Sunetci, Onder; Pori, Pauli; Vuk, Angela Šurca

    2014-09-01

    Fluoropolymer conformal coatings were applied to electronic boards (EBs) and cured at room temperature or 80°C. The coatings were first deposited on model substrate, i.e. aluminium alloy AA 2024 and tested for their anticorrosion properties with a potentiodynamic polarisation technique. The cathodic current densities ranged from 10-9-10-10 A/cm2, approaching the lower current limit after the addition of TiO2 nanoparticles into the formulation. Application of fluoropolymer-based formulation was performed via spray-coating deposition. Examination of the coverage of EBs under UV light, which is commonly used in industry, revealed that some components might not be entirely covered. In the search for other possible analytical tools of coverage with protective coatings, optical microscopy and confocal Raman spectroscopy were investigated.

  17. Nanoplasmonic electron acceleration in silver clusters studied by angular-resolved electron spectroscopy

    International Nuclear Information System (INIS)

    The nanoplasmonic field enhancement effects in the energetic electron emission from few-nm-sized silver clusters exposed to intense femtosecond dual pulses are investigated by high-resolution double differential electron spectroscopy. For moderate laser intensities of 1014 W cm−2, the delay-dependent and angular-resolved electron spectra show laser-aligned emission of electrons up to keV kinetic energies, exceeding the ponderomotive potential by two orders of magnitude. The importance of the nanoplasmonic field enhancement due to resonant Mie-plasmon excitation observed for optimal pulse delays is investigated by a direct comparison with molecular dynamics results. The excellent agreement of the key signatures in the delay-dependent and angular-resolved spectra with simulation results allows for a quantitative analysis of the laser and plasmonic contributions to the acceleration process. The extracted field enhancement at resonance verifies the dominance of surface-plasmon-assisted re-scattering. (paper)

  18. Bore-auger servo-mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Levkovich, P.Ye.; Bolotov, N.L.; Kiselev, Ye.I.; Opal' ko, L.L.; Podubniy, V.I.; Savich, N.S.; Tverezyy, Yu.F.

    1980-06-06

    A bore-auger servo-mechanism is proposed for a drilling machine. This unit consists of a drilling bit, an auger boring section with a screw-type surface, upper and lower cutting disks, mounted onto the supports between the main auger sections, and a linear auger section with lateral ties. In order to simplify construction, the upper cutting disk is equipped with its own auger bits, both below and above the disks, thus facilitating interaction with the screw-type surface of the auger sections.

  19. El proyecto AUGER

    Science.gov (United States)

    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.

  20. Attosecond photoelectron spectroscopy of electron transport in solids

    International Nuclear Information System (INIS)

    Time-resolved photoelectron spectroscopy of condensed matter systems in the attosecond regime promises new insights into excitation mechanisms and transient dynamics of electrons in solids. This timescale became accessible directly only recently with the development of the attosecond streak camera and of laser systems providing few-cycle, phase-controlled laser pulses in the near-infrared, which are used to generate isolated, sub-femtosecond extreme-ultraviolet pulses with a well-defined timing with respect to the near-infrared pulse. Employing these pulses, the attosecond streak camera offers time resolutions as short as a few 10 attoseconds. In the framework of this thesis, a new, versatile experimental apparatus combining attosecond pulse generation in gases with state of the art surface science techniques is designed, constructed, and commissioned. Employing this novel infrastructure and the technique of the attosecond transient recorder, we investigate transport phenomena occurring after photoexcitation of electrons in tungsten and rhenium single crystals and show that attosecond streaking is a unique method for resolving extremely fast electronic phenomena in solids. It is demonstrated that electrons originating from different energy levels, i.e. from the conduction band and the 4f core level, are emitted from the crystal surface at different times. The origin of this time delay, which is below 150 attoseconds for all studied systems, is investigated by a systematic variation of several experimental parameters, in particular the photon energy of the employed attosecond pulses. These experimental studies are complemented by theoretical studies of the group velocity of highly-excited electrons based on ab initio calculations. While the streaking technique applied on single crystals can provide only information about the relative time delay between two types of photoelectrons, the absolute transport time remains inaccessible. We introduce a scheme of a reference

  1. Attosecond photoelectron spectroscopy of electron transport in solids

    Energy Technology Data Exchange (ETDEWEB)

    Magerl, Elisabeth

    2011-03-31

    Time-resolved photoelectron spectroscopy of condensed matter systems in the attosecond regime promises new insights into excitation mechanisms and transient dynamics of electrons in solids. This timescale became accessible directly only recently with the development of the attosecond streak camera and of laser systems providing few-cycle, phase-controlled laser pulses in the near-infrared, which are used to generate isolated, sub-femtosecond extreme-ultraviolet pulses with a well-defined timing with respect to the near-infrared pulse. Employing these pulses, the attosecond streak camera offers time resolutions as short as a few 10 attoseconds. In the framework of this thesis, a new, versatile experimental apparatus combining attosecond pulse generation in gases with state of the art surface science techniques is designed, constructed, and commissioned. Employing this novel infrastructure and the technique of the attosecond transient recorder, we investigate transport phenomena occurring after photoexcitation of electrons in tungsten and rhenium single crystals and show that attosecond streaking is a unique method for resolving extremely fast electronic phenomena in solids. It is demonstrated that electrons originating from different energy levels, i.e. from the conduction band and the 4f core level, are emitted from the crystal surface at different times. The origin of this time delay, which is below 150 attoseconds for all studied systems, is investigated by a systematic variation of several experimental parameters, in particular the photon energy of the employed attosecond pulses. These experimental studies are complemented by theoretical studies of the group velocity of highly-excited electrons based on ab initio calculations. While the streaking technique applied on single crystals can provide only information about the relative time delay between two types of photoelectrons, the absolute transport time remains inaccessible. We introduce a scheme of a reference

  2. Tetrachloridocuprates(II—Synthesis and Electron Paramagnetic Resonance (EPR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Peter Strauch

    2012-02-01

    Full Text Available Ionic liquids (ILs on the basis of metal containing anions and/or cations are of interest for a variety of technical applications e.g., synthesis of particles, magnetic or thermochromic materials. We present the synthesis and the results of electron paramagnetic resonance (EPR spectroscopic analyses of a series of some new potential ionic liquids based on tetrachloridocuprates(II, [CuCl4]2−, with different sterically demanding cations: hexadecyltrimethylammonium 1, tetradecyltrimethylammonium 2, tetrabutylammonium 3 and benzyltriethylammonium 4. The cations in the new compounds were used to achieve a reasonable separation of the paramagnetic Cu(II ions for EPR spectroscopy. The EPR hyperfine structure was not resolved. This is due to the exchange broadening, resulting from still incomplete separation of the paramagnetic Cu(II centers. Nevertheless, the principal values of the electron Zeemann tensor (g║ and g┴ of the complexes could be determined. Even though the solid substances show slightly different colors, the UV/Vis spectra are nearly identical, indicating structural changes of the tetrachloridocuprate moieties between solid state and solution. The complexes have a promising potential e.g., as high temperature ionic liquids, as precursors for the formation of copper chloride particles or as catalytic paramagnetic ionic liquids.

  3. Handbook of Applied Solid State Spectroscopy

    CERN Document Server

    Vij, D. R

    2006-01-01

    Solid-State spectroscopy is a burgeoning field with applications in many branches of science, including physics, chemistry, biosciences, surface science, and materials science. Handbook of Applied Solid-State Spectroscopy brings together in one volume information about various spectroscopic techniques that is currently scattered in the literature of these disciplines. This concise yet comprehensive volume covers theory and applications of a broad range of spectroscopies, including NMR, NQR, EPR/ESR, ENDOR, scanning tunneling, acoustic resonance, FTIR, auger electron emission, x-ray photoelectron emission, luminescence, and optical polarization, and more. Emphasis is placed on fundamentals and current methods and procedures, together with the latest applications and developments in the field.

  4. Two-dimensional electronic spectroscopy of beta-carotene.

    Science.gov (United States)

    Christensson, Niklas; Milota, Franz; Nemeth, Alexandra; Sperling, Jaroslaw; Kauffmann, Harald F; Pullerits, Tönu; Hauer, Jürgen

    2009-12-24

    Two-dimensional electronic spectroscopy (2D) has been applied to beta-carotene in solution to shine new light on the ultrafast energy dissipation network in carotenoids. The ability of 2D to relieve spectral congestion provides new experimental grounds for resolving the rise of the excited state absorption signal between 18,000 and 19,000 cm(-1). In this spectral region, the pump-probe signals from ground state bleach and stimulated emission overlap strongly. Combined modeling of the time-evolution of 2D spectra as well as comparison to published pump-probe data allow us to draw conclusions on both the electronic structure of beta-carotene as well as the spectral densities giving rise to the observed optical lineshapes. To account for the experimental observations on all time scales, we need to include a transition in the visible spectral range from the first optically allowed excited state (S(2)-->S(n2)). We present data from frequency resolved transient grating and pump-probe experiments confirming the importance of this transition. Furthermore, we investigate the role and nature of the S* state, controversially debated in numerous previous studies. On the basis of the analysis of Feynman diagrams, we show that the properties of S*-related signals in chi(3) techniques like pump-probe and 2D can only be accounted for if S* is an excited electronic state. Against this background, we discuss a new interpretation of pump-deplete-probe and intensity-dependent pump-probe experiments. PMID:19954155

  5. Structural comparison between MgO/Fe(0 0 1) and MgO/Fe(0 0 1)–p(1 × 1)O interfaces for magnetic tunneling junctions: An Auger electron diffraction study

    International Nuclear Information System (INIS)

    Magnetic tunnel junctions based on MgO(0 0 1) barriers and ferromagnetic electrodes, such as Fe/MgO/Fe, represent a very popular and widely investigated subject in the field of spin-electronics because of the large values of magnetoresistance shown by these systems. In this paper, the structural properties of MgO thin films grown onto Fe(0 0 1) and MgO/Fe(0 0 1)–p(1 × 1)O surfaces, with MgO thickness ranging from 2 to 14 equivalent monolayers, have been investigated by means of Auger electron diffraction. The structural order and the crystal quality of the MgO films result practically independent from the template, the latter being either the clean Fe(0 0 1) surface or the oxidized Fe(0 0 1)–p(1 × 1)O one. This is confirmed by numerical simulations, showing that, apart from the first two MgO layers close to the interface, the structure is unaffected by the choice of the starting surface. By a structural point of view, we can conclude that Fe(0 0 1)–p(1 × 1)O is a good candidate for the role of bottom electrode for the realization of MgO-based magnetic tunnelling junctions, also considering its higher chemical stability and reproducibility if compared to the clean Fe(0 0 1) surface.

  6. Stereographic intensity projections of elastically backscattered electrons in directional elastic peak electron spectroscopy: Experiment and theory

    International Nuclear Information System (INIS)

    The stereographic intensity projections of elastically backscattered electrons for Au(1 1 1) were obtained by using directional elastic peak electron spectroscopy (DEPES). An enhancement of the recorded signal is observed when primary electrons with energies ranging from 0.5 to 2.0 keV strike the crystalline sample along the close-packed rows of atoms, proving the sensitivity of DEPES to the short atomic chain axial order. Besides, the obtained data reveal the threefold symmetry of the substrate. Experimental data are compared with the results of single scattering cluster (SSC) and multiple scattering (MS) calculations by means of contrast and an R-factor analysis. A satisfactory agreement between experiment and theory is found when the third scattering order is taken into account in MS approximation.

  7. Valence electron energy-loss spectroscopy in monochromated scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    With the development of monochromators for (scanning) transmission electron microscopes, valence electron energy-loss spectroscopy (VEELS) is developing into a unique technique to study the band structure and optical properties of nanoscale materials. This article discusses practical aspects of spatially resolved VEELS performed in scanning transmission mode and the alignments necessary to achieve the current optimum performance of ∼0.15 eV energy resolution with an electron probe size of ∼1 nm. In particular, a collection of basic concepts concerning the acquisition process, the optimization of the energy resolution, the spatial resolution and the data processing are provided. A brief study of planar defects in a Y1Ba2Cu3O7-δ high-temperature superconductor illustrates these concepts and shows what kind of information can be accessed by VEELS

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

    Science.gov (United States)

    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.

  9. The Pierre Auger Observatory Upgrade - Preliminary Design Report

    CERN Document Server

    Aab, A; Aglietta, M; Ahn, E J; Samarai, I Al; Albuquerque, I F M; Allekotte, I; Allison, P; Almela, A; Castillo, J Alvarez; Alvarez-Muñiz, J; Batista, R Alves; Ambrosio, M; Aminaei, A; Anchordoqui, L; Andringa, S; Aramo, C; Arqueros, F; Arsene, N; Asorey, H; Assis, P; Aublin, J; Ave, M; Avenier, M; Avila, G; Awal, N; Badescu, A M; Barber, K B; Bäuml, J; 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; Brack, J; Brancus, I; Bridgeman, A; Brogueira, P; Brown, W C; 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; Neto, J R T de Mello; De Mitri, I; de Oliveira, J; de Souza, V; del Peral, L; Deligny, O; Dembinski, H; Dhital, N; Di Giulio, C; Di Matteo, A; Diaz, J C; Castro, M L Díaz; Diogo, F; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dorofeev, A; Hasankiadeh, Q Dorosti; 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; Fernandes, M; Fick, B; Figueira, J M; Filevich, A; Filipčič, A; Fox, B D; Fratu, O; Freire, M M; Fuchs, B; Fujii, T; García, B; 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; Berisso, M Gómez; Vitale, P F Gómez; 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; Hemery, N; Herve, 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; Kégl, B; Keilhauer, B; Keivani, A; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Krause, R; Krohm, N; Krömer, O; Kuempel, D; Mezek, G Kukec; Kunka, N; LaHurd, D; Latronico, L; Lauer, R; Lauscher, M; Lautridou, P; Coz, S Le; Lebrun, D; Lebrun, P; de Oliveira, M A Leigui; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; Lopes, L; López, R; Casado, A López; Louedec, K; Lu, L; Lucero, A; Malacari, M; Maldera, S; Mallamaci, M; Maller, J; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, V; Mariş, I C; Marsella, G; Martello, D; Martin, L; Martinez, H; Bravo, O Martínez; Martraire, D; Meza, J J Masías; 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; Meyhandan, R; 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; Muller, M A; Müller, G; Müller, S; Mussa, R; Navarra, G; 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; Ochilo, L; Oikonomou, F; Olinto, A; Pacheco, N; Selmi-Dei, D Pakk; 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; Purrello, V; Quel, E J; Querchfeld, S; Quinn, S; Rautenberg, J; Ravel, O; Ravignani, D; Reinert, D; Revenu, B; Ridky, J; Riggi, S; Risse, M; Ristori, P; Rizi, V; de Carvalho, W Rodrigues; Fernandez, G Rodriguez; Rojo, J Rodriguez; Rodríguez-Frías, M D; Rogozin, D; Rosado, J; Roth, M; Roulet, E; Rovero, A C; Saffi, S J; Saftoiu, A; Salamida, F; Salazar, H; Saleh, A; Greus, F Salesa; Salina, G; Sánchez, F; Sanchez-Lucas, P; Santos, E; Santos, E M; Sarazin, F; Sarkar, B; Sarmento, R; 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; Sidelnik, I; Sigl, G; Sima, O; Śmiałkowski, A; Šmída, R; Snow, G R; Sommers, P; Sorokin, J; Squartini, R; Srivastava, Y N; Stanca, D; Stanič, S; Stapleton, J; Stasielak, J; Stephan, M; Stutz, A; Suarez, F; Suomijärvi, T; Supanitsky, A D; Sutherland, M S; Swain, J; Szadkowski, Z; Taborda, O A; Tapia, A; Tepe, A; Theodoro, V M; Timmermans, C; Peixoto, C J Todero; Toma, G; Tomankova, L; Tomé, B; Tonachini, A; Elipe, G Torralba; Machado, D Torres; Travnicek, P; Trini, M; Ulrich, R; Unger, M; Urban, M; Galicia, J F Valdés; Valiño, I; Valore, L; van Aar, G; van Bodegom, P; Berg, A M van den; van Velzen, S; van Vliet, A; Varela, E; Cárdenas, B Vargas; 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; Zhu, Y; Zimmermann, B; Ziolkowski, M; Zong, Z; Zuccarello, F

    2016-01-01

    The Pierre Auger Observatory has begun a major Upgrade of its already impressive capabilities, with an emphasis on improved mass composition determination using the surface detectors of the Observatory. Known as AugerPrime, the upgrade will include new 4 m$^2$ plastic scintillator detectors on top of all 1660 water-Cherenkov detectors, updated and more flexible surface detector electronics, a large array of buried muon detectors, and an extended duty cycle for operations of the fluorescence detectors. This Preliminary Design Report was produced by the Collaboration in April 2015 as an internal document and information for funding agencies. It outlines the scientific and technical case for AugerPrime. We now release it to the public via the arXiv server. We invite you to review the large number of fundamental results already achieved by the Observatory and our plans for the future.

  10. The Pierre Auger Observatory Upgrade - Preliminary Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Aab, Alexander [Univ. Siegen (Germany); et al.

    2016-04-12

    The Pierre Auger Observatory has begun a major Upgrade of its already impressive capabilities, with an emphasis on improved mass composition determination using the surface detectors of the Observatory. Known as AugerPrime, the upgrade will include new 4 m2 plastic scintillator detectors on top of all 1660 water-Cherenkov detectors, updated and more flexible surface detector electronics, a large array of buried muon detectors, and an extended duty cycle for operations of the fluorescence detectors. This Preliminary Design Report was produced by the Collaboration in April 2015 as an internal document and information for funding agencies. It outlines the scientific and technical case for AugerPrime. We now release it to the public via the arXiv server. We invite you to review the large number of fundamental results already achieved by the Observatory and our plans for the future.

  11. 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.

    Science.gov (United States)

    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

  12. Electronic structure of germanium selenide investigated using ultra-violet photo-electron spectroscopy

    International Nuclear Information System (INIS)

    The valence band electronic structure of GeSe single crystals has been investigated using angle resolved photoemission spectroscopy (ARPES) and x-ray photoelectron spectroscopy. The experimentally observed bands from ARPES, match qualitatively with our LDA-based band structure calculations along the Γ–Z, Γ–Y and Γ–T symmetry directions. The valence band maximum occurs nearly midway along the Γ–Z direction, at a binding energy of −0.5 eV, substantiating the indirect band gap of GeSe. Non-dispersive features associated with surface states and indirect transitions have been observed. The difference in hybridization of Se and Ge 4p orbitals leads to the variation of dispersion along the three symmetry directions. The predominance of the Se 4pz orbitals, evidenced from theoretical calculations, may be the cause for highly dispersive bands along the Γ–T direction. Detailed electronic structure analysis reveals the significance of the cation–anion 4p orbitals hybridization in the valence band dispersion of IV–VI semiconductors. This is the first comprehensive report of the electronic structure of a GeSe single crystal using ARPES in conjugation with theoretical band structure analysis. (paper)

  13. Electronic structure of germanium selenide investigated using ultra-violet photo-electron spectroscopy

    Science.gov (United States)

    Mishra, P.; Lohani, H.; Kundu, A. K.; Patel, R.; Solanki, G. K.; Menon, Krishnakumar S. R.; Sekhar, B. R.

    2015-07-01

    The valence band electronic structure of GeSe single crystals has been investigated using angle resolved photoemission spectroscopy (ARPES) and x-ray photoelectron spectroscopy. The experimentally observed bands from ARPES, match qualitatively with our LDA-based band structure calculations along the Γ-Z, Γ-Y and Γ-T symmetry directions. The valence band maximum occurs nearly midway along the Γ-Z direction, at a binding energy of -0.5 eV, substantiating the indirect band gap of GeSe. Non-dispersive features associated with surface states and indirect transitions have been observed. The difference in hybridization of Se and Ge 4p orbitals leads to the variation of dispersion along the three symmetry directions. The predominance of the Se 4pz orbitals, evidenced from theoretical calculations, may be the cause for highly dispersive bands along the Γ-T direction. Detailed electronic structure analysis reveals the significance of the cation-anion 4p orbitals hybridization in the valence band dispersion of IV-VI semiconductors. This is the first comprehensive report of the electronic structure of a GeSe single crystal using ARPES in conjugation with theoretical band structure analysis.

  14. Electron paramagnetic resonance spectroscopy using a direct current-SQUID magnetometer directly coupled to an electron spin ensemble

    Science.gov (United States)

    Toida, Hiraku; Matsuzaki, Yuichiro; Kakuyanagi, Kosuke; Zhu, Xiaobo; Munro, William J.; Nemoto, Kae; Yamaguchi, Hiroshi; Saito, Shiro

    2016-02-01

    We demonstrate electron spin polarization detection and electron paramagnetic resonance (EPR) spectroscopy using a direct current superconducting quantum interference device (dc-SQUID) magnetometer. Our target electron spin ensemble is directly bonded to the dc-SQUID magnetometer that detects electron spin polarization induced by an external magnetic field or EPR in a micrometer-sized area. The minimum distinguishable number of polarized spins and sensing volume of the electron spin polarization detection and the EPR spectroscopy are estimated to be ˜106 and ˜10-10 cm3 (˜0.1 pl), respectively.

  15. Identification of irradiated rice noodles by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) spectroscopy has been applied to the identification of the irradiation of a wide variety of foods. In this study, ESR was applied to identify irradiated rice noodles. A detailed ESR investigation of irradiated noodles was carried out in the dose range 0.5–3 kGy. The stability of the radiation-induced ESR signal at cold (−4 °C) and room (25 °C) temperatures was studied over a storage period of 24 weeks. Irradiated rice noodle samples exhibited a strong, symmetric doublet ESR signal centered at g = 2.0, whereas unirradiated noodle exhibited a very weak signal. The ESR signal intensity increased linearly with radiation dose ranging from 0.5 to 3 kGy. Keeping the samples at −4 °C and 25 °C for 24 weeks caused decreases of 50% and 90% in the ESR signal intensities, respectively. However, long-term decay data at room temperature showed that the ESR technique could be used to identify irradiated rice noodles up to 24 weeks following irradiation.

  16. Analysis of contaminants on electronic components by reflectance FTIR spectroscopy

    International Nuclear Information System (INIS)

    The analysis of electronic component contaminants by infrared spectroscopy is often a difficult process. Most of the contaminants are very small, which necessitates the use of microsampling techniques. Beam condensers will provide the required sensitivity but most require that the sample be removed from the substrate before analysis. Since it can be difficult and time consuming, it is usually an undesirable approach. Micro ATR work can also be exasperating, due to the difficulty of positioning the sample at the correct place under the ATR plate in order to record a spectrum. This paper describes a modified reflection beam condensor which has been adapted to a Nicolet 7199 FTIR. The sample beam is directed onto the sample surface and reflected from the substrate back to the detector. A micropositioning XYZ stage and a close-focusing telescope are used to position the contaminant directly under the infrared beam. It is possible to analyze contaminants on 1 mm wide leads surrounded by an epoxy matrix using this device. Typical spectra of contaminants found on small circuit boards are included

  17. Electron-energy-loss spectroscopy of transition-metal carbides

    International Nuclear Information System (INIS)

    Electron-energy-loss spectroscopy (EELS) was applied to several problems dealing with the transition-metal carbides. First, narrow (200A) precipitates of TiC were identified in a single crystal of titanium diboride. Second, the carbon concentration in individual stacking faults of TaC was determined to be less than in the surrounding matrix, and the implications of this finding for crystal structure and mechanical properties were discussed. Next, thin films of amorphous carbon and TiO were studied with EELS. Experimental cross sections for C and Ti were obtained from these spectra and used for quantitative analysis of a material of known stoichiometry, V6C5 (by assuming V and Ti cross sections equal), and one of unknown stoichiometry, a cemented carbide composed of 1 to 5 μm grains of TiC/sub x/ embedded in a Ni-Mo binder. These experimental cross sections gave a C/V ratio of 0.84, very close to the expected value of 0.833, and a C/Ti ratio of 0.81 for a grain of TiC/sub x/, a reasonable value of x in these materials. Two other methods of determining cross sections were applied: calculated cross sections based on a hydrogenic model gave inaccurate results, perhaps due to the inadequacy of the model for these transition metals; and efficiency factors applied to the Bethe cross section gave reasonable results, but inferior to those from the experimental cross sections

  18. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    International Nuclear Information System (INIS)

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio

  19. Manipulation of resonant Auger processes with strong optical fields

    Science.gov (United States)

    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.

  20. Preparation of graphene oxide and characterisation using electron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: • Graphene oxide by ozonation and cold glow air plasma from 8 nm graphene platelets. • XPS, REELS for characterising the surface chemical composition and the structure. • C sp3 and carbon–oxygen groups content smaller contrary to wet chemical methods. • REELS shows decreasing number of graphene layers: platelets > ozone > plasma. • Oxidation separates graphene layers via incorporating interlayer oxygen-H2O groups. - Abstract: Graphene oxide was prepared from commercial graphene powder (G) platelets of 8 nm thickness by oxidation in ozone (G-O3) and low-energy (cold) glow air plasma in a pink region (G-PP). X-ray photoelectron spectroscopy (XPS) was applied for chemical characterisation of the atomic content and for obtaining quantitative information on C hybridisation. Reflection electron energy loss spectroscopy (REELS) was used for characterising the surface structure including the content of surface and bulk carbon atoms of sp2 and sp3 hybridisation. The G-O3 and G-PP graphene oxide samples contain a low amount of C sp3 bonds and carbon–oxygen groups in comparison to graphene oxide prepared by the “wet” chemical methods. Oxidation of commercial graphene platelets powder, especially in air plasma, leads to increasing surface C sp3 and significantly bulk C sp3 contributions, indicating intercalation by oxygen groups. The intensity ratio of the REELS π + σ C sp2 bulk to the C sp2 surface energy loss peaks, decreasing in the order G>G-O3>G-PP, indicates exfoliation of layers in G-O3 and G-PP by oxygen functional groups and water with decreasing average number of layers in graphene oxide nanostructures due to oxidation. Although, the “wet” chemical methods are more effective for oxidation leading to a larger amount of C sp3 and oxygen groups, the proposed methods of oxidation by ozonation and in air plasma are inexpensive, safe, effective, environmentally friendly and do not result in toxic chemical waste products

  1. Electron Emission Spectroscopy of InGaN/GaN Light Emitting Diodes

    Science.gov (United States)

    Iveland, Justin Thomas

    The effect of efficiency droop in light emitting diodes (LEDs) is a huge roadblock for consumer lighting adoption. To prevent loss of efficiency from droop, LEDs must be operated at lower current density, requiring a larger epitaxial area and increasing the overall cost. Proposed mechanisms responsible for droop include, among others, carrier delocalization from indium rich regions, overshoot and leakage current, and Auger recombination. Current methods used to understand droop mechanisms are indirect, and often rely on models that have no unique solution. It is clear that a direct measurement method and a deeper understanding of the fate of injected carriers not contributing to radiative recombination is needed to focus improvement efforts on materials and structures to help identify and mitigate the relevant droop mechanism(s). By analyzing the energy of vacuum emitted electrons from a forward biased LED, we can gain direct information of their origin internally. The study of vacuum emitted electrons has existed for almost 130 years with the discovery of the photoelectric effect. Advancements in electron energy analysis techniques have led to the direct measurement of conduction band structures and transport properties in many commonly used semiconductors such as: InP, GaAs, Si, and recently GaN. The kinetic energy of the vacuum emitted electrons from an InGaN/GaN LED was analyzed and three peaks were identified: First, a low energy peak, resulting from photoexcited electrons generated by diode light. Second, a mid-energy peak, generated by the accumulation of thermalized electrons at the bottom of the Gammaconduction band valley. Third, a high-energy peak is generated by an accumulation of electron at the bottom of a low lying side-valley "L". Auger recombination is uniquely identifiable as it is the only proposed droop mechanism capable of generating hot carriers and solely responsible for the population of electrons found in the L-valley. Two control

  2. Auger voltage imaging for junction delineation

    International Nuclear Information System (INIS)

    A new method for the two-dimensional characterization of dopant profiles in semiconductors, called 'Auger Voltage Contrast' (AVC), is introduced, which investigates the effect of the dopant on the electronic properties of the device, e.g. the change of the Fermi level across a semiconductor surface. This change can be detected by extracting the shift of the Si-LVV Auger peak with respect to a reference spectrum. AVC linescans across pn-junctions have been modeled using the MINIMOS-NT device simulator, finding the energy shift across a pn-junction is not directly representative for the dopant distribution itself, but that the turning point of the AVC energy shift coincides with the position of the junction, making AVC an applicable tool for junction delineation. Furthermore, contamination experiments showed that small amounts of oxide on the semiconductor surface do not influence the contrast in an AVC image. For processing such an energy shift map, a software tool has been developed, which is able to obtain a map that assigns four regions to the semiconductor: regions that are p-type, regions that are n-type, regions that cannot be assigned to either type due to contamination and regions that act as the 'error bar' between p and n. Experimental data obtained from two-dimensional test structures have been processed with this tool. The resulting images clearly show the n- and p-type regions, and the width of the region corresponding to the junction are clearly below 50 nm. (author)

  3. XUV Spectroscopy of Isochorically Heated Metals at the Free Electron Laser Flash

    International Nuclear Information System (INIS)

    Spectroscopic investigations of metals, interacting with intense, femtosecond XUV pulses at 13.5 nm wavelength (92 eV photon energy), are presented. The experiments were performed at the FEL FLASH of the DESY lab in Hamburg. Metallic samples are dominantly ionized by direct photo-absorption of inner-shell bound electrons. Processes such as radiative and Auger decays lead to emission of fluorescence radiation as well as bremsstrahlung and ionic line radiation. By applying QMD and Monte-Carlo simulation, we compare our experimental observations with theoretical predictions and gain insight into the complex interaction of metals with intense XUV radiation. This topic shows novel features of isochoric heating of warm dense plasmas by FEL radiation, complementary to heating by optical laser irradiation. (author)

  4. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Science.gov (United States)

    Ferreira da Silva, F.; Lange, E.; Limão-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Hubin-Franskin, M.-J.; Delwiche, J.; Brunger, M. J.; Neves, R. F. C.; Lopes, M. C. A.; de Oliveira, E. M.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Blanco, F.; García, G.; Lima, M. A. P.; Jones, D. B.

    2015-10-01

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5-10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  5. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    International Nuclear Information System (INIS)

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range

  6. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others

    2015-10-14

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  7. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nenov, Artur, E-mail: Artur.Nenov@unibo.it; Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K. [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); Rivalta, Ivan [Université de Lyon, CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France); Cerullo, Giulio [Dipartimento di Fisica, Politecnico di Milano, IFN-CNR, Piazza Leonardo Da Vinci 32, IT-20133 Milano (Italy); Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States); Garavelli, Marco, E-mail: marco.garavelli@unibo.it, E-mail: marco.garavelli@ens-lyon.fr [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); Université de Lyon, CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France)

    2015-06-07

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040–1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  8. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    International Nuclear Information System (INIS)

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040–1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  9. Atom location using scanning transmission electron microscopy based on electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Full text: The technique of atom location by channelling enhanced microanalysis (ALCHEMI) using cross section data, measured as a function of electron beam orientation, has been widely implemented by many researchers. The accurate application of ALCHEMI, usually based on energy dispersive x-ray analysis (EDX), requires knowledge, from first principles, of the relative delocalization of the inner-shell ionization interaction (see for example Oxley and Allen, 1998; Oxley et al., 1999). Scanning transmission electron microscopy (STEM) based on electron energy loss spectroscopy (EELS) also provides information about the location of atoms of different types within the crystal lattice. Unlike high angle annular dark field (HAADF), EELS provides a unique signal for each atom type. In conjunction with highly focused probes, allowing near atomic resolution, this makes possible, in principle, the application of ALCHEMI like techniques to STEM images to determine the distribution of impurities within the unit cell. The accurate interpretation of STEM results requires that both the inner-shell ionization interaction and resulting ionization cross section or image be correctly modelled. We present model calculations demonstrating the in principle application of ALCHEMI type techniques to STEM images pertinent to EELS. The inner-shell ionisation interaction is modelled using Hartree-Fock wave functions to describe the atomic bound states and Hartree-Slater wave functions to describe the continuum states. The wave function within the crystal is calculated using boundary conditions appropriate for a highly focussed probe (Rossouw and Allen, 2001) and STEM images or ionisation cross sections are simulated using an inelastic cross section formulation that correctly accounts for the contribution from both dynamical electrons and those dechannelled by absorptive scattering processes such as thermal diffuse scattering (TDS). Copyright (2002) Australian Society for Electron Microscopy

  10. Experimental KLM + KLN Auger spectrum of Cu

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh., E-mail: inoyatov@jinr.ru [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Institute of Applied Physics, National University, Tashkent (Uzbekistan); Perevoshchikov, L.L. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Zhdanov, V.S. [Institute of Nuclear Physics, Almaty (Kazakhstan); Filosofov, D.V. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Kovalík, A. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, Řež near Prague (Czech Republic)

    2013-08-15

    Highlights: •The KLM Auger spectrum of Cu was measured for the first time in detail. •Energies and relative intensities of nine resolved spectrum components were determined. •Semi-empirical KLM energy predictions and experiment agree mostly within 3σ with the exception of the transitions involving the M{sub 4,5} atomic subshells. •It was found that the KLM transition rates at Z = 29 should be calculated relativistically in intermediate coupling scheme. -- Abstract: The KLM + KLN Auger electron spectrum of Cu (Z = 29) emitted in the electron capture decay of radioactive {sup 65}Zn in a solid matrix was investigated for the first time using a combined electrostatic electron spectrometer adjusted to the 7 eV instrumental resolution. Energies and relative intensities of nine resolved spectrum components were determined and compared with theoretical expectations. An agreement within 3σ was found between the semi-empirical predictions for the KLM transition energies by Larkins and the experimental data with the exception of the weak (KL{sub 2}M{sub 4,5} + KL{sub 2}N{sub 1}) and (KL{sub 3}M{sub 4,5} + KL{sub 3}N{sub 1}) lines where the differences reached 5σ. From a comparison of the measured relative KLM transition intensities with available theoretical results a conclusion was derived that calculations of the KLM transition rates at Z = 29 should be based on intermediate coupling of angular momenta and take into account relativistic effects.

  11. Detection of irradiated lamb meat by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Present paper describes the potential of ESR spectroscopy for identification of radical ions in irradiated lamb meat containing bone. Irradiation induced a characteristic ESR signal due to CO2- in the bone tissue which was not detected in the non-irradiated samples. Intensity of ESR signal was proportional to irradiation dose up to 5 kGy. These results have shown that ESR spectroscopy can be effectively used to detect irradiated lamb meat containing bone tissue. (author). 2 refs., 2 figs

  12. Electron energy loss spectroscopy of free C60 and C70

    International Nuclear Information System (INIS)

    Electron energy loss spectroscopy has been performed with samples of pure C60 and C70 using primary electron energies between 10 and 1100 eV. The experimental data could be explained in terms of optically forbidden and allowed transitions, and by collective excitations (plasmons), which could be distinguished by their dependence on the energy of the primary electron. (orig.)

  13. X-ray laser spectroscopy with an electron beam ion trap at the free electron laser LCLS

    International Nuclear Information System (INIS)

    We present a first laser spectroscopy experiment in the keV energy regime, performed at the Free-Electron Laser LCLS at Stanford. An electron beam ion trap was used to provide a target of highly charged O, F and Fe ions. The resonant fluorescence spectra obtained for various transitions were calibrated to simultaneously measured Lyman lines of hydrogenic ions.

  14. Theory of attosecond absorption spectroscopy in krypton

    DEFF Research Database (Denmark)

    Baggesen, Jan Conrad; Lindroth, Eva; Madsen, Lars Bojer

    2012-01-01

    A theory for time-domain attosecond pump–attosecond probe photoabsorption spectroscopy is formulated and related to the atomic response. The theory is illustrated through a study of attosecond absorption spectroscopy in krypton. The atomic parameters entering the formulation such as energies and...... Auger widths, as well as wave functions and dipole coupling matrix elements, are determined by accurate many-body structure calculations. We create a hole in a valence shell by an attosecond pump, couple an inner-shell electron to the hole by an attosecond probe, and then monitor the formation of the...

  15. Scanning electron microscopy and X-ray spectroscopy applied to mycelial phase of sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    M. Thibaut

    1975-04-01

    Full Text Available Scanning electron microscopy applied to the mycelial phase of Sporothrix schenckii shows a matted mycelium with conidia of a regular pattern. X-Ray microanalysis applied in energy dispersive spectroscopy and also in wavelength dispersive spectroscopy reveals the presence of several elements of Mendeleef's classification.

  16. Bandgap determination of P(VDF–TrFE) copolymer film by electron energy loss spectroscopy

    Indian Academy of Sciences (India)

    Dipankar Mandal; K Henkel; K Müller; D Schmeißer

    2010-08-01

    The ferroelectric of poly(vinylidene fluoride trifluoroethylene), P(VDF–TrFE) is confirmed for 100 nm thickness spin coated copolymer film. The homogeneous coverage of the copolymer film is investigated by the help of X-ray photoelectron spectroscopy (XPS). Most importantly, the existing bandgap in the crystalline phase of the copolymer is determined directly from the electron energy loss spectroscopy (EELS).

  17. The human polynucleotide kinase/phosphatase (hPNKP) inhibitor A12B4C3 radiosensitizes human myeloid leukemia cells to Auger electron-emitting anti-CD123 111In-NLS-7G3 radioimmunoconjugates

    International Nuclear Information System (INIS)

    Introduction: Leukemia stem cells (LSCs) are believed to be responsible for initiating and propagating acute myeloid leukemia (AML) and for causing relapse after treatment. Radioimmunotherapy (RIT) targeting these cells may improve the treatment of AML, but is limited by the low density of target epitopes. Our objective was to study a human polynucleotide kinase/phosphatase (hPNKP) inhibitor that interferes with DNA repair as a radiosensitizer for the Auger electron RIT agent, 111In-NLS-7G3, which recognizes the CD123+/CD131- phenotype uniquely displayed by LSCs. Methods: The surviving fraction (SF) of CD123+/CD131- AML-5 cells exposed to 111In-NLS-7G3 (33–266 nmols/L; 0.74 MBq/μg) or to γ-radiation (0.25-5 Gy) was determined by clonogenic assays. The effect of A12B4C3 (25 μmols/L) combined with 111In-NLS-7G3 (16–66 nmols/L) or with γ-radiation (0.25–2 Gy) on the SF of AML-5 cells was assessed. The density of DNA double-strand breaks (DSBs) in the nucleus was measured using the γ-H2AX assay. Cellular dosimetry was estimated based on the subcellular distribution of 111In-NLS-7G3 measured by cell fractionation. Results: Binding of 111In-NLS-7G3 to AML-5 cells was reduced by 2.2-fold in the presence of an excess (1 μM) of unlabeled NLS-7G3, demonstrating specific binding to the CD123+/CD131- epitope. 111In-NLS-7G3 reduced the SF of AML-5 cells from 86.1 ± 11.0% at 33 nmols/L to 10.5 ± 3.6% at 266 nmols/L. Unlabeled NLS-7G3 had no significant effect on the SF. Treatment of AML-5 cells with γ-radiation reduced the SF from 98.9 ± 14.9% at 0.25 Gy to 0.03 ± 0.1% at 5 Gy. A12B4C3 combined with 111In-NLS-7G3 (16–66 nmols/L) enhanced the cytotoxicity up to 1.7-fold compared to treatment with radioimmunoconjugates alone and was associated with a 1.6-fold increase in DNA DSBs in the nucleus. A12B4C3 enhanced the cytotoxicity of γ-radiation (0.25–0.5 Gy) on AML-5 cells by up to 1.5-fold, and DNA DSBs were increased by 1.7-fold. Exposure to 111In-NLS-7G3

  18. Electronic properties of Mn-phthalocyanine–C{sub 60} bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Friedrich [Center for Free-Electron Laser Science/DESY, Notkestraße 85, D-22607 Hamburg (Germany); Herzig, Melanie; Knupfer, Martin [FW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Lupulescu, Cosmin [Institute of Optics and Atomic Physics, TU Berlin, Straße des 17. Juni 135, D-10623 Berlin (Germany); Darlatt, Erik; Gottwald, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, D-10587 Berlin (Germany); Eberhardt, Wolfgang [Center for Free-Electron Laser Science/DESY, Notkestraße 85, D-22607 Hamburg (Germany); Institute of Optics and Atomic Physics, TU Berlin, Straße des 17. Juni 135, D-10623 Berlin (Germany)

    2015-11-14

    The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C{sub 60} (MnPc:C{sub 60}) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C{sub 60}. Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C{sub 60} bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C{sub 60} to MnPc thin films.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Santamaria, Florencio [Los Alamos National Laboratory; Vela, Javier [Los Alamos National Laboratory; Schaller, Richard D [Los Alamos National Laboratory; Hollingsworth, Jennifer A [Los Alamos National Laboratory; Klimov, Victor I [Los Alamos National Laboratory; Chen, Yongfen [NON LANL

    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.

  20. Simulations for MARTA (Muon Auger RPC for the Tank Array)

    Energy Technology Data Exchange (ETDEWEB)

    Maurizio, D.; Shellard, R.C. [CBPF, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Full text: The Muon Auger RPC for the Tank Array (MARTA) detector is being studied as part of the Pierre Auger Observatory upgrade. The aim of this detector is to provide a very good capability to discriminate muons in an air shower. This property is very important for it allows Auger to investigate the changes in the hadronic interactions at high energies; to improve the energy evolution by better understanding the muon component of the showers, as well as the missing energy into neutrinos; to increase the primary photon discrimination. A simulation package was developed to integrate with the regular Auger software to describe the behaviour of the detector and allow the fine running of the parameters that define the detector. This package use Geant4 to describe the detector and the electronics response. However this package is very computer intensive so we are developing a fast version of simulation, using Python as the program language. In this paper we describe some of physics parameters results provided by the simulation. (author)

  1. Angle-Resolved Photoemission Spectroscopy on Electronic Structure and Electron-Phonon Coupling in Cuprate Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X.J.

    2010-04-30

    In addition to the record high superconducting transition temperature (T{sub c}), high temperature cuprate superconductors are characterized by their unusual superconducting properties below T{sub c}, and anomalous normal state properties above T{sub c}. In the superconducting state, although it has long been realized that superconductivity still involves Cooper pairs, as in the traditional BCS theory, the experimentally determined d-wave pairing is different from the usual s-wave pairing found in conventional superconductors. The identification of the pairing mechanism in cuprate superconductors remains an outstanding issue. The normal state properties, particularly in the underdoped region, have been found to be at odd with conventional metals which is usually described by Fermi liquid theory; instead, the normal state at optimal doping fits better with the marginal Fermi liquid phenomenology. Most notable is the observation of the pseudogap state in the underdoped region above T{sub c}. As in other strongly correlated electrons systems, these unusual properties stem from the interplay between electronic, magnetic, lattice and orbital degrees of freedom. Understanding the microscopic process involved in these materials and the interaction of electrons with other entities is essential to understand the mechanism of high temperature superconductivity. Since the discovery of high-T{sub c} superconductivity in cuprates, angle-resolved photoemission spectroscopy (ARPES) has provided key experimental insights in revealing the electronic structure of high temperature superconductors. These include, among others, the earliest identification of dispersion and a large Fermi surface, an anisotropic superconducting gap suggestive of a d-wave order parameter, and an observation of the pseudogap in underdoped samples. In the mean time, this technique itself has experienced a dramatic improvement in its energy and momentum resolutions, leading to a series of new discoveries not

  2. INSTRUMENTATION, ELECTRON OPTICS AND X-RAY SPECTROSCOPY

    OpenAIRE

    Mulvey, T

    1984-01-01

    Recent instrumental developments in the field of electron probe instrumentation are reviewed. These include electron guns, lens systems and back-scattered electron (z contrast) detectors. Desirable changes in instrumental design are discussed for the analysis of thin specimens by the use of energy dispersive spectrometers.

  3. Atomic scale imaging and spectroscopy of individual electron trap states using force detected dynamic tunnelling

    International Nuclear Information System (INIS)

    We report the first atomic scale imaging and spectroscopic measurements of electron trap states in completely non-conducting surfaces by dynamic tunnelling force microscopy/spectroscopy. Single electrons are dynamically shuttled to/from individual states in thick films of hafnium silicate and silicon dioxide. The new method opens up surfaces that are inaccessible to the scanning tunnelling microscope for imaging and spectroscopy on an atomic scale.

  4. [A high resolution projection electron spectrometers]: Final report 1978-1987

    International Nuclear Information System (INIS)

    The main emphasis of the work has been to study inner shell ionization processes. The signatures have been K x-rays or K Auger transitions. We have worked with semiconductor or Bragg x-ray spectrometers. Toward the end of the contract we concentrated on projectile electron spectroscopy. These topics and other atomic physics projects are described briefly in this progress report

  5. Electronic structure investigation of oxidized aluminium films with electron momentum spectroscopy

    International Nuclear Information System (INIS)

    Electron momentum spectroscopy (EMS) of (e, 2e) measurements with oxidized aluminium thin films have been performed. Due to the surface sensitive mature of the EMS spectrometer employed the measured (e, 2e) events come from the front oxidized layer as viewed by the electron detectors. The measurements show clearly two major features in the spectral momentum density distribution and they are related to the upper valence band and the lower valence band of aluminum oxide. The first is a 'dual parabola' energy-momentum dispersion pattern spanning about 8 eV in the upper valence band. This 'dual parabola' pattern has been qualitatively reproduced by a linear muffin-tin orbital (LMTO) calculation on spherically averaged α-A12O3 with nearly the same energy span. In the lower valence band, the LMTO calculation indicates a dispersion spanning about 5 eV, and the measured spectral momentum density plot shows a similar 'bowl' shape but with less dispersion. The possible causes which blur the dispersion in the lower valence band are discussed. Other features in the spectral momentum density distribution are also discussed and compared with the LMTO calculation. 45 refs., 1 tab., 10 figs

  6. Electron-Induced Vibrational Spectroscopy. A New and Unique Tool To Unravel the Molecular Structure of Polymer Surfaces

    OpenAIRE

    Pireaux, J. J.; Gregoire, Ch.; Caudano, R.; Rei Vilar, M.; Brinkhuis, R; Schouten, A.J.

    1991-01-01

    Among the surface-sensitive spectroscopies used to characterize clean and surface-modified polymers, one technique has rather recently emerged as a very promising complementary tool. High-resolution electron energy loss spectroscopy, or electron-induced vibrational spectroscopy, has potentially all the attributes of the well-known optical (infrared and Raman) spectroscopies; it clearly adds to X-ray photoelectron spectroscopy the possibility to go beyond surface elemental and chemical analysi...

  7. Hydrogen slush production with a large auger

    Science.gov (United States)

    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.

  8. Magnetic field influence on Auger effect on shallow donors in CdF2:Mn+ luminescence

    International Nuclear Information System (INIS)

    Direct observation of the suppression of the Auger effect on shallow donors by magnetic field in the luminescence of manganese ions in semiconducting CdF2:Mn crystals is presented. The magnetic field decreases the probability of the Auger effect, which is spin-dependent energy transfer from the manganese ions to the electrons occupying shallow donors. This results in the increase in the decay times of the luminescence. (author)

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

    International Nuclear Information System (INIS)

    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+*, A2+*, A3+) 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.

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

    Science.gov (United States)

    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.

  11. Soft x-ray spectroscopy for probing electronic and chemical states of battery materials

    Science.gov (United States)

    Wanli, Yang; Ruimin, Qiao

    2016-01-01

    The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode-electrolyte interfaces, chemical reactions take place with evolving electron states. In addition to the extensive studies of material synthesis, electrochemical, structural, and mechanical properties, soft x-ray spectroscopy provides unique opportunities for revealing the critical electron states in batteries. This review discusses some of the recent soft x-ray spectroscopic results on battery binder, transition-metal based positive electrodes, and the solid-electrolyte-interphase. By virtue of soft x-ray’s sensitivity to electron states, the electronic property, the redox during electrochemical operations, and the chemical species of the interphases could be fingerprinted by soft x-ray spectroscopy. Understanding and innovating battery technologies need a multimodal approach, and soft x-ray spectroscopy is one of the incisive tools to probe the chemical and physical evolutions in batteries.

  12. Soft X-ray and electron spectroscopy to determine the electronic structure of materials for photoelectrochemical hydrogen production

    International Nuclear Information System (INIS)

    Highlights: ► Soft X-ray and electron spectroscopies were used to study materials for photoelectrochemical water splitting. ► These spectroscopies provide detailed information on the chemical and electronic structure of the investigated materials. ► Positions of the conduction band minimum and valence band maximum of WO3 and WO3:Mo were determined. ► Surface instabilities of ZnO:Zn3N2 films were identified and investigated in detail. ► It is shown how these spectroscopies can be used to study materials in an in situ fashion, e.g., in an electrolyte. -- Abstract: To optimize materials and devices for solar photoelectrochemical hydrogen production, a detailed understanding of the chemical and electronic properties, in particular at the reactive surfaces and interfaces, is needed. In this review article we will show how electron and soft X-ray spectroscopies can provide such information. We will present exemplary studies using X-ray photoelectron spectroscopy, soft X-ray emission spectroscopy, UV photoelectron spectroscopy, and inverse photoemission. While the first two techniques mainly give insight into the chemical properties at and near the surface, the latter two methods allow us to derive the electronic levels relevant for photoelectrochemical water splitting at the surface of the investigated material. Ultimately, the ideal experiment would be performed in situ, in which the device is studied under working conditions, i.e., in a liquid environment and under illumination. We will give a short outlook on how this can be achieved experimentally under the strict requirements of the measurement environment

  13. The detail study of the LMN+LMM Auger spectrum of .sup.67.sub.30Zn from the EC-decay of .sup.67.sub.31Ga

    Czech Academy of Sciences Publication Activity Database

    Kovalík, Alojz; Lubashevsky, A. V.; Filosofov, D. V.; Inoyatov, A. K.; Gorozhankin, V. M.; Vylov, Ts.; Mahmoud, M. A.; Štekl, I.

    2003. s. 43. [International Conference of the Nuclear Spectroscopy and Nuclear Structure "Nucleus-2003" /53./. 07.11.2003-10.11.2003, Moscow] R&D Projects: GA ČR GA202/02/0157 Institutional research plan: CEZ:AV0Z1048901 Keywords : Auger effect * LMM Auger group Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  14. The KLL Auger spectrum of .sup.67.sub.Zn from the EC-decay of .sup61.sub.31Ga

    Czech Academy of Sciences Publication Activity Database

    Kovalík, Alojz; Lubashevsky, A. V.; Filosofov, D. V.; Inoyatov, A. K.; Gorozhankin, V. M.; Vylov, Ts.; Štekl, I.

    2003. s. 40. [International Conference Nuclear Spectroscopy and Nuclear Structure "Nucleus-2003" /53./. 07.11.2003-10.11.2003, Moscow] R&D Projects: GA ČR GA202/02/0157 Institutional research plan: CEZ:AV0Z1048901 Keywords : Auger effect * KLL Auger group Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  15. The first measurement of the KLM+KLN Auger spectrum of .sup.67.sub30Zn from the EC-decay of .sup.61.sub31Ga

    Czech Academy of Sciences Publication Activity Database

    Kovalík, Alojz; Lubashevsky, A. V.; Filosofov, D. V.; Inoyatov, A. K.; Gorozhankin, V. M.; Vylov, Ts.; Štekl, I.

    2003. s. 41. [International Conference Nuclear Spectroscopy and Nuclear Structure "Nucleus-2003" /53./. 07.11.2003-10.11.2003, Moscow] R&D Projects: GA ČR GA202/02/0157 Institutional research plan: CEZ:AV0Z1048901 Keywords : Auger effect * KLM Auger group Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  16. Moessbauer spectroscopy, electron microscopy and electron diffraction studies of small particle magnetic systems: Identification of disease specific haemosiderins

    International Nuclear Information System (INIS)

    Moessbauer spectroscopy has shown that the iron-containing cores of the biological iron storage material haemosiderin produced under normal and various pathological conditions are significantly different in their magnetic properties. The differences have been correlated with information on the particle size, morphology, crystallinity and mineral form of the haemosiderin cores obtained by complementary electron microscopy and electron diffraction studies. These results have important implications for the use of Moessbauer spectroscopy in determining the properties of small particle magnetic systems and also considerable relevance for the improved understanding and treatment of iron overload disease. (orig.)

  17. Time-of-flight spectroscopy of electrons transmitted through very thin films

    Czech Academy of Sciences Publication Activity Database

    Daniel, Benjamin

    Vienna: IAP, 2015. s. 37. [Low Energy Electrons: Dynamics and Correlation near Surfaces and Nanostructures (LEE2015). 07.09.2015-11.09.2015, Herstein] Institutional support: RVO:68081731 Keywords : Time-of-flight spectroscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Spectroscopy of highly charged multi-electron ions

    International Nuclear Information System (INIS)

    Systematic studies of highs charged neonlike and nickellike ions as well as several open-shell ions performed on an electron beam ion trap are described and used to assess the accuracy of structure calculations of multi-electron ions. Discrepancies are found that can be attributed to inaccuracies in accounting for electron correlations and in estimating quantum electrodynamical effects. Documenting the effects of level crossings, we demonstrate that these discrepancies are compounded by uncertainties in assigning the respective contributions from quantum electrodynamics to each of the two strongly interacting levels undergoing the crossing

  19. Copper/oxide interface formation: a vibrational and electronic investigation by electron spectroscopies

    Science.gov (United States)

    Conard, T.; Ghijsen, J.; Vohs, J. M.; Thiry, P. A.; Caudano, R.; Johnson, R. L.

    1992-04-01

    In this study, we deposited copper on a MgO(100) surface at room temperature (using a Knudsen cell) and studied the interface formation using electron spectroscopy. The evolution of the AES peak intensities showed that copper grows on MgO(100) in the Stranski-Krastanov mode. In HREELS experiments, the intensity and the position of the energy loss corresponding to the MgO surface optical phonon at 80.7 meV, both decrease with increasing Cu coverage. These results agree with theoretical spectra simulated from the dielectric theory by considering a Cu 2O overlayer on a semi-infinite MgO crystal substrate at the beginning of the growth. From the HREELS data, both the formation of a homogeneous Cu metallic overlayer or a CuO overlayer on MgO can be ruled out. The synchrotron-radiation (SR) photoemission measurements were performed in the vicinity of the Cu3p3d resonance. The positions of the Cu resonance peaks as a function of Cu coverage on MgO show that at low coverage the difference in energy between the main Cu 3d peak and the resonance peak is close to that found in Cu 2O and at higher coverage close to metallic copper indicating the formation of an interacting phase at the beginning followed by the growth of metallic copper.

  20. Vacuum ultraviolet spectroscopy of some hydrocarbons by electron impact technique

    International Nuclear Information System (INIS)

    A detailed description of the construction and operation of the electron impact spectrometer of the Electron Impact Laboratory at the Chemistry Institute of Federal University of Rio de Janeiro are presented. The main characteristics of this spectrometer are: incident energy from 0.5 to 3.0 KeV; angular range from -600 to + 600; energy loss from 0 to 500 eV; energy resolution from 0.5 to 2.5 eV and; electron velocity analyser equal to electrostatic (Mollenstedt type. The data acquisition system is based on a microcomputer Motorola; recently an APPLE II system has been incorporated to the spectrometer. Electron energy loss spectra for the nitrogen molecule as well as for some hydrocarbons (C2H6, C2H4, C2H2) have been obtained. The data were converted into double differential cross sections and generalized oscillator strenghts. (author)

  1. Practical guide to surface science and spectroscopy

    CERN Document Server

    Chung, Yip-Wah

    2001-01-01

    Practical Guide to Surface Science and Spectroscopy provides a practical introduction to surface science as well as describes the basic analytical techniques that researchers use to understand what occurs at the surfaces of materials and at their interfaces. These techniques include auger electron spectroscopy, photoelectron spectroscopy, inelastic scattering of electrons and ions, low energy electron diffraction, scanning probe microscopy, and interfacial segregation. Understanding the behavior of materials at their surfaces is essential for materials scientists and engineers as they design and fabricate microelectronics and semiconductor devices. The book gives over 100 examples, discussion questions and problems with varying levels of difficulty. Included with this book is a CD-ROM, which not only contains the same information, but also provides many elements of animation and interaction that are not easily emulated on paper. In diverse subject matters ranging from the operation of ion pumps, computer-...

  2. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  3. Observation of conformers with laser electronic spectroscopy in supersonic molecular beams

    Science.gov (United States)

    Philis, John G.; Kosmidis, Constantine E.; Tsekeris, Pericles

    1998-07-01

    We discuss the ability and effectiveness of electronic spectroscopy to reveal rotational isomerism by presenting some examples of the S1 implied by S0 electronic spectra of non-rigid molecules. One or two photon electronic spectra have multiple features when the molecule has more than one conformational preference. Torsional bands showing up in the spectrum complicate the assignment of conformers. Hole burning experiments give definite conclusions on the existence of rotational isomerism and an example from the literature is given.

  4. Probing the photonic local density of states with electron energy loss spectroscopy

    OpenAIRE

    García de Abajo, Francisco Javier; Kociak, M.

    2008-01-01

    Electron energy loss spectroscopy performed in transmission electron microscopes is shown to directly render the photonic local density of states with unprecedented spatial resolution, currently below the nanometer. Two special cases are discussed in detail: (i) 2D photonic structures with the electrons moving along the translational axis of symmetry and (ii) quasiplanar plasmonic structures under normal incidence. Nanophotonics in general and plasmonics, in particular, should benefit from th...

  5. Study of electron-irradiated silicon thin films using transient photocurrent spectroscopy

    OpenAIRE

    Reynolds, S; Astakhov, O.; Smirnov, V.(Joint Institute for Nuclear Research, Dubna, Russia)

    2014-01-01

    Electron irradiation of silicon thin films creates localised states, which degrade theiropto-electronic properties. We present a series of transient photocurrent spectroscopy (TPC)measurements on electron-irradiated amorphous and microcrystalline silicon films, annealed atprogressively increasing temperatures. This has enabled localised states associated with bothdangling bonds and conduction band tails to be examined over a wide energy range.Trends inthe evolution of the DOS following electr...

  6. Stereoscopic electron spectroscopy of solar hard X-ray flares with a single spacecraft

    OpenAIRE

    Kontar, Eduard P.; John C. Brown

    2006-01-01

    Hard X-ray (HXR) spectroscopy is the most direct method of diagnosing energetic electrons in solar flares. Here we present a technique which allows us to use a single HXR spectrum to determine an effectively stereoscopic electron energy distribution. Considering the Sun's surface to act as a 'Compton mirror' allows us to look at emitting electrons also from behind the source, providing vital information on downward-propagating particles. Using this technique we determine simultaneously the el...

  7. Electron spectroscopies for simultaneous chemical and electrical analysis

    International Nuclear Information System (INIS)

    Electrons are used as spectroscopic probes to determine elemental composition and chemistry, and are also useful as probes of the electrical properties of devices and materials. In this paper, four examples with incident and emitted electrons were used to evaluate the electrical and chemical properties of samples. These examples were the electrical conductivity of an Ag-epoxy composite, the electric field in an avalanche photodiode near breakdown, the mechanism of conductivity of semi-insulating polycrystalline films, and the charge at an oxide/semiconductor interface for high-k applications. This kind of work is very much in the spirit of the work done by Prof. Sefik Suzer.

  8. Action spectroscopy of gas-phase carboxylate anions by multiple photon IR electron detachment/attachment

    CERN Document Server

    Steill, Jeffrey D

    2008-01-01

    We report on a form of gas-phase anion action spectroscopy based on infrared multiple photon electron detachment and subsequent capture of the free electrons by a neutral electron scavenger in a Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. This method allows one to obtain background-free spectra of strongly bound anions, for which no dissociation channels are observed. The first gas-phase spectra of the acetate and propionate anions are presented using SF6 as electron scavenger and a free electron laser as source of intense and tunable infrared radiation. To validate the method, we compare infrared spectra obtained through multiple photon electron detachment/attachment and multiple photon dissociation for the benzoate anion. In addition, different electron acceptors are used, comparing both associative and dissociative electron capture. The relative energies of dissociation (by CO2 loss) and electron detachment are investigated for all three anions by DFT and CCSD(T) methods. DFT calcu...

  9. Resolving molecular vibronic structure using high-sensitivity two-dimensional electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bizimana, Laurie A.; Brazard, Johanna; Carbery, William P.; Gellen, Tobias; Turner, Daniel B., E-mail: dturner@nyu.edu [Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003 (United States)

    2015-10-28

    Coherent multidimensional optical spectroscopy is an emerging technique for resolving structure and ultrafast dynamics of molecules, proteins, semiconductors, and other materials. A current challenge is the quality of kinetics that are examined as a function of waiting time. Inspired by noise-suppression methods of transient absorption, here we incorporate shot-by-shot acquisitions and balanced detection into coherent multidimensional optical spectroscopy. We demonstrate that implementing noise-suppression methods in two-dimensional electronic spectroscopy not only improves the quality of features in individual spectra but also increases the sensitivity to ultrafast time-dependent changes in the spectral features. Measurements on cresyl violet perchlorate are consistent with the vibronic pattern predicted by theoretical models of a highly displaced harmonic oscillator. The noise-suppression methods should benefit research into coherent electronic dynamics, and they can be adapted to multidimensional spectroscopies across the infrared and ultraviolet frequency ranges.

  10. Atmospheric Corrosion on Steel Studied by Conversion Electron Moessbauer Spectroscopy

    International Nuclear Information System (INIS)

    In order to investigate initial products on steel by atmospheric corrosion, conversion electron Moessbauer measurements were carried out at temperatures between 15 K and room temperature. From the results obtained at low temperatures, it was found that the corrosion products on steel consisted of ferrihydrite.

  11. A study of electron scattering through noise spectroscopy

    NARCIS (Netherlands)

    Kumar, Manohar

    2012-01-01

    Charge counting statistics (C.S.) of traversing electron in quantum devices like atomic-molecular junctions is sensitive to the local perturbation in the charge field at the contact and in the quantum channels. The first cumulant of C.S. i.e. current-voltage characteristic of such devices has been t

  12. Intramembrane Polarity by Electron Spin Echo Spectroscopy of Labeled Lipids

    Science.gov (United States)

    Bartucci, Rosa; Guzzi, Rita; Marsh, Derek; Sportelli, Luigi

    2003-01-01

    The association of water (D2O) with phospholipid membranes was studied by using pulsed-electron spin resonance techniques. We measured the deuterium electron spin echo modulation of spin-labeled phospholipids by D2O in membranes of dipalmitoyl phosphatidylcholine with and without 50 mol% of cholesterol. The Fourier transform of the relaxation-corrected two-pulse echo decay curve reveals peaks, at one and two times the deuterium NMR frequency, that arise from the dipolar hyperfine interaction of the deuterium nucleus with the unpaired electron spin of the nitroxide-labeled lipid. For phosphatidylcholine spin-labeled at different positions down the sn-2 chain, the amplitude of the deuterium signal decreases toward the center of the membrane, and is reduced to zero from the C-12 atom position onward. At chain positions C-5 and C-7 closer to the phospholipid headgroups, the amplitude of the deuterium signal is greater in the presence of cholesterol than in its absence. These results are in good agreement with more indirect measurements of the transmembrane polarity profile that are based on the 14N-hyperfine splittings in the conventional continuous-wave electron spin resonance spectrum. PMID:12547783

  13. Electronic structure of palladium and its relation to uv spectroscopy

    DEFF Research Database (Denmark)

    Christensen, N.E.

    1976-01-01

    The electronic-energy-band structure of palladium has been calculated by means of the relativistic augmented-plane-wave method covering energies up to 30 eV above the Fermi level. The optical interband transitions producing structure in the dielectric function up to photon energies of 25 eV have...

  14. Numerical analysis of field-assisted sodium migration in electron-irradiated glasses

    International Nuclear Information System (INIS)

    The sodium profile evolution in electron-irradiated glasses is shown to be governed by the ordinary and field-assisted diffusion with an electric field function of depth. Experimental results on Na surface concentration modification during Auger electron spectroscopy are also reproduced very well. It is also shown that the determination of profiles of Na against depth offers a unique tool to estimate the structure and strength of the electric field which builds up in electron-irradiated glass systems. (author)

  15. Conformational and nuclear dynamics effects in molecular Auger spectra: fluorine core-hole decay in CF4

    International Nuclear Information System (INIS)

    In a molecular Auger spectrum information on the decaying state is implicitly ensemble-averaged. For a repulsive core-ionized state, for example, contributions from all parts of its potential curve are superimposed in the Auger spectrum. Using carbon tetrafluoride (CF4, tetrafluoromethane), we demonstrate for the first time that these contributions can be disentangled by recording photoelectron–Auger electron coincidence spectra with high energy resolution. For the F K-VV spectrum of CF4, there are significant differences in the Auger decay at different intermediate state (single core hole) geometries. With the help of calculations, we show that these differences result primarily from zero-point fluctuations in the neutral molecular ground state, but are amplified by the nuclear dynamics during Auger decay. (paper)

  16. Adsorption of oxygen on a nickel covered SrTiO3(100) surface studied by means of Auger electron spectroscopy and work function measurements

    International Nuclear Information System (INIS)

    The interaction of oxygen with evaporated Ni films on an Fe-doped SrTiO3(100) substrate was investigated by means of LEED, AES and work function measurements (WF) at room temperature. The adsorption of oxygen takes place on the nickel overlayer firstly by chemisorption on nickel step sites, accompanied by a reduction of the WF, and secondly on terrace sites, followed by a WF increase. After the chemisorption phase, the oxidation of the nickel overlayer starts with NiO island formation followed by bulk NiO development, which is marked by a second WF reduction. The adsorption phases of oxygen correspond closely to those of oxygen on single crystals of nickel. This indicates that the character of the Ni predeposited layers on strontium titanate seems to be metallic

  17. The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu

    International Nuclear Information System (INIS)

    We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in the paper.

  18. Development of Holmium-163 Electron-Capture Spectroscopy with Transition-Edge Sensors

    Science.gov (United States)

    Croce, M. P.; Rabin, M. W.; Mocko, V.; Kunde, G. J.; Birnbaum, E. R.; Bond, E. M.; Engle, J. W.; Hoover, A. S.; Nortier, F. M.; Pollington, A. D.; Taylor, W. A.; Weisse-Bernstein, N. R.; Wolfsberg, L. E.; Hays-Wehle, J. P.; Schmidt, D. R.; Swetz, D. S.; Ullom, J. N.; Barnhart, T. E.; Nickles, R. J.

    2016-01-01

    Calorimetric decay energy spectroscopy of electron-capture-decaying isotopes is a promising method to achieve the sensitivity required for electron neutrino mass measurement. The very low total nuclear decay energy (Q_EC attractive for high-precision electron-capture spectroscopy (ECS) near the kinematic endpoint, where the neutrino momentum goes to zero. In the ECS approach, an electron-capture-decaying isotope is embedded inside a microcalorimeter designed to capture and measure the energy of all the decay radiation except that of the escaping neutrino. We have developed a complete process for proton irradiation-based isotope production, isolation, and purification of ^{163} Ho. We have developed transition-edge sensors for this measurement and methods for incorporating ^{163} Ho into high-resolution microcalorimeters, and have measured the electron-capture spectrum of ^{163} Ho. We present our work in these areas and discuss the measured spectrum and its comparison to current theory.

  19. [Electron energy loss spectroscopy of surfaces]. Final report

    International Nuclear Information System (INIS)

    We have developed and implemented techniques for calculating the large angle cross section for scattering of electrons off surface vibrations, and we have also developed models of surface lattice dynamics (along with new computational methods) that accounts nicely for data on a variety of systems. We are in a position to combine these two lines of investigation, to calculate in detail the cross sections for surface phonon excitation on clean and adsorbate covered surfaces

  20. Neutron-electron spectroscopy: selection rules and relativistic effects

    International Nuclear Information System (INIS)

    Neutron scattering permits the study of transitions within and between Russell-Saunders multiplets. Applied to rare-earth and actinide metals and compounds the technique provides information that is not obtained with other experimental probes. For such materials, scattering from an isolated ion is a good guide for the interpretation of data. Selection rules for this model are discussed. These are different in a relativistic treatment of atomic electron states. Earlier work on this topic by Stassis and Deckman is clarified. (author)

  1. Single-atom electron energy loss spectroscopy of light elements

    OpenAIRE

    Senga, Ryosuke; Suenaga, Kazu

    2015-01-01

    Light elements such as alkali metal (lithium, sodium) or halogen (fluorine, chlorine) are present in various substances and indeed play significant roles in our life. Although atomic behaviours of these elements are often a key to resolve chemical or biological activities, they are hardly visible in transmission electron microscope because of their smaller scattering power and higher knock-on probability. Here we propose a concept for detecting light atoms encaged in a nanospace by means of e...

  2. Spectroscopy of Argon Excited in an Electron Beam Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2005-04-18

    Argon is one of the gases best investigated and most widely used in plasma discharge devices for a multitude of applications that range from wavelength reference standards to controlled fusion experiments. Reviewing atomic physics and spectroscopic problems in various ionization stages of Ar, the past use and future options of employing an electron beam ion trap (EBIT) for better and more complete Ar data in the x-ray, EUV and visible spectral ranges are discussed.

  3. Neutron-electron spectroscopy: selection rules and relativistic effects

    International Nuclear Information System (INIS)

    Neutron scattering permits the study of transitions within and between Russell-Saunders multiplets. Applied to rare earth and actinide metals and compounds the technique provides information that is not obtained with other experimental probes. For such materials, scattering from an isolated ion is a good guide for the interpretation of data. Selection rules for this model are discussed. These are different in a relativistic treatment of atomic electron states. Work on this topic by Stassis and Deckman (1976 J. Phys. C9 2241) is clarified. (author)

  4. Multidimensional electronic spectroscopy of phycobiliproteins from cryptophyte algae

    Science.gov (United States)

    Turner, Daniel

    2011-03-01

    We describe new spectroscopic measurements which reveal additional information regarding the observed quantum coherences in proteins extracted from photosynthetic algae. The proteins we investigate are the phycobiliproteins phycoerythrin 545 and phycocyanin 645. Two new avenues have been explored. We describe how changes to the chemical and biological environment impact the quantum coherence present in the 2D electronic correlation spectrum. We also use new multidimensional spectroscopic techniques to reveal insights into the nature of the quantum coherence and the nature of the participating states.

  5. Investigation of the Unoccupied Electronic Structure of UO2 with Bermstrahlung Isochromat Spectroscopy and X-Ray Absorption Spectroscopy

    International Nuclear Information System (INIS)

    UO2 is an important nuclear fuel for electrical power generation. Global goal : Actinides (5f electron systems) exhibit fascinating physical and chemical properties, due to 5f electron correlation, including the highly radioactive systems such as Pu. Onsite Instrumentation: A spectroscopic system containing spin resolved photoelectron spectroscopy (SRPES) and bremsstrahlung isochromat spectroscopy (BIS) has been built and commissioned at LLNL. ALS Instrumentation: The XAS was done on Beamline 8. Both Total Electron Yield (TEY) and Total Fluorescence Yield (TFY) were used. TFY is less surface sensitive than TEY. A combined experimental and theoretical study of Uranium Dioxide has been performed, including XAS, BIS, XPS and spectral simulations. The Conduction Bands or Unoccupied Density of States (UDOS) of UO2 are shown to be divided into two parts, the lower region being U5f-O2p and the upper region U6d-O2p. This means that UO2 is an f-f Mott Insulator, electron-correlated system. The keys to success with the XAS were the (1) the utilization of both TEY and TFY and (2) the accurate co-location of the uranium and oxygen states, which in turn hinged upon a proper calibration of the gratings of the beamline monochromator. The calibration of the gratings was greatly aided by the availibility of the O1s XAS from 1st, 2nd and 3rd order light. The success of this approach to differentiation of the Uranium UDOS into U5f and U6d components is of great importance and bodes well for its application to other actinide systems. Our ultimate goal remains Pu and its electron correlation.

  6. X-ray and photoelectron spectroscopy of the structure, reactivity, and electronic structure of semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, K.S.

    2000-05-01

    Semiconductor nanocrystals are a system which has been the focus of interest due to their size dependent properties and their possible use in technological applications. Many chemical and physical properties vary systematically with the size of the nanocrystal and thus their study enables the investigation of scaling laws. Due to the increasing surface to volume ratio as size is decreased, the surfaces of nanocrystals are expected to have a large influence on their electronic, thermodynamic, and chemical behavior. In spite of their importance, nanocrystal surfaces are still relatively uncharacterized in terms of their structure, electronic properties, bonding, and reactivity. Investigation of nanocrystal surfaces is currently limited by what techniques to use, and which methods are suitable for nanocrystals is still being determined. This work presents experiments using x-ray and electronic spectroscopies to explore the structure, reactivity, and electronic properties of semiconductor (CdSe, InAs) nanocrystals and how they vary with size. Specifically, x-ray absorption near edge spectroscopy (XANES) in conjunction with multiple scattering simulations affords information about the structural disorder present at the surface of the nanocrystal. X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS) probe the electronic structure in terms of hole screening, and also give information about band lineups when the nanocrystal is placed in electric contact with a substrate. XPS of the core levels of the nanocrystal as a function of photo-oxidation time yields kinetic data on the oxidation reaction occurring at the surface of the nanocrystal.

  7. Imaging photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

    International Nuclear Information System (INIS)

    An imaging photoelectron photoion coincidence spectrometer at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source is presented and a few initial measurements are reported. Monochromatic synchrotron VUV radiation ionizes the cooled or thermal gas-phase sample. Photoelectrons are velocity focused, with better than 1 meV resolution for threshold electrons, and also act as start signal for the ion time-of-flight analysis. The ions are accelerated in a relatively low, 40-80 V cm-1 field, which enables the direct measurement of rate constants in the 103-107 s-1 range. All electron and ion events are recorded in a triggerless multiple-start/multiple-stop setup, which makes it possible to carry out coincidence experiments at >100 kHz event frequencies. As examples, the threshold photoelectron spectrum of the argon dimer and the breakdown diagrams for hydrogen atom loss in room temperature methane and the chlorine atom loss in cold chlorobenzene are shown and discussed.

  8. Applications of time-domain spectroscopy to electron-phonon coupling dynamics at surfaces.

    Science.gov (United States)

    Matsumoto, Yoshiyasu

    2014-10-01

    Photochemistry is one of the most important branches in chemistry to promote and control chemical reactions. In particular, there has been growing interest in photoinduced processes at solid surfaces and interfaces with liquids such as water for developing efficient solar energy conversion. For example, photoinduced charge transfer between adsorbates and semiconductor substrates at the surfaces of metal oxides induced by photogenerated holes and electrons is a core process in photovoltaics and photocatalysis. In these photoinduced processes, electron-phonon coupling plays a central role. This paper describes how time-domain spectroscopy is applied to elucidate electron-phonon coupling dynamics at metal and semiconductor surfaces. Because nuclear dynamics induced by electronic excitation through electron-phonon coupling take place in the femtosecond time domain, the pump-and-probe method with ultrashort pulses used in time-domain spectroscopy is a natural choice for elucidating the electron-phonon coupling at metal and semiconductor surfaces. Starting with a phenomenological theory of coherent phonons generated by impulsive electronic excitation, this paper describes a couple of illustrative examples of the applications of linear and nonlinear time-domain spectroscopy to a simple adsorption system, alkali metal on Cu(111), and more complex photocatalyst systems. PMID:25139240

  9. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope

    Science.gov (United States)

    Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

    2016-08-01

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  10. Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

    Science.gov (United States)

    Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

    2016-09-01

    A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20-55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for 241Am.

  11. Imaging electron dynamics with time- and angle-resolved photoelectron spectroscopy

    CERN Document Server

    Popova-Gorelova, Daria; Santra, Robin

    2016-01-01

    We theoretically study how time- and angle-resolved photoemission spectroscopy can be applied for imaging coherent electron dynamics in molecules. We consider a process in which a pump pulse triggers coherent electronic dynamics in a molecule by creating a valence electron hole. An ultrashort extreme ultraviolet (XUV) probe pulse creates a second electron hole in the molecule. Information about the electron dynamics is accessed by analyzing angular distributions of photoemission probabilities at a fixed photoelectron energy. We demonstrate that a rigorous theoretical analysis, which takes into account the indistinguishability of transitions induced by the ultrashort, broadband probe pulse and electron hole correlation effects, is necessary for the interpretation of time- and angle-resolved photoelectron spectra. We show how a Fourier analysis of time- and angle-resolved photoelectron spectra from a molecule can be applied to follow its electron dynamics by considering photoelectron distributions from an indol...

  12. First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids

    Energy Technology Data Exchange (ETDEWEB)

    Olovsson, Weine, E-mail: weine.olovsson@gmail.co [Department of Materials Science and Engineering, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Marten, Tobias [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden); Holmstroem, Erik [Instituto de Fisica, Universidad Austral de Chile, Valdivia (Chile); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johansson, Boerje [Department of Physics and Materials Science, Uppsala University, P.O. Box 530, SE-751 21 Uppsala (Sweden); Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Abrikosov, Igor A. [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden)

    2010-05-15

    We present a brief overview of recent theoretical studies of the core-level binding energy shift (CLS) in solid metallic materials. The focus is on first principles calculations using the complete screening picture, which incorporates the initial (ground state) and final (core-ionized) state contributions of the electron photoemission process in X-ray photoelectron spectroscopy (XPS), all within density functional theory (DFT). Considering substitutionally disordered binary alloys, we demonstrate that on the one hand CLS depend on average conditions, such as volume and overall composition, while on the other hand they are sensitive to the specific local atomic environment. The possibility of employing layer resolved shifts as a tool for characterizing interface quality in fully embedded thin films is also discussed, with examples for CuNi systems. An extension of the complete screening picture to core-core-core Auger transitions is given, and new results for the influence of local environment effects on Auger kinetic energy shifts in fcc AgPd are presented.

  13. Frenkel exciton model of electron energy loss spectroscopy in α-PTCDA

    International Nuclear Information System (INIS)

    Recent experimental findings concerning electron energy loss spectroscopy in α-Perylene-tetracarboxylic-dianhydride are analysed in terms of a Frenkel exciton model. Taking into account the energy dispersion of excitations with finite momentum transfer, the k-dependence of the dielectric tensor and the corresponding electron energy loss functions can be calculated. The exciton dispersion with a minimum at k0 yields a red shift of the lineshape of loss functions at large k, as observed experimentally

  14. Visualizing plasmon coupling in closely-spaced chains of Ag nanoparticles by electron energy loss spectroscopy

    OpenAIRE

    Song, Fengqi; Wang, Tingyu; Wang, Xuefeng; Xu, Changhui; He, Longbing; Wan, Jianguo; Van Haesendonck, Chris; Simon P. Ringer; Han, Min; Liu, Zongwen; Wang, Guanghou

    2012-01-01

    Anisotropic plasmon coupling in closely-spaced chains of Ag nanoparticles was visualized using the electron energy loss spectroscopy in a scanning transmission electron microscope. For dimers as the simplest chain, mapping the plasmon excitations with nanometers' spatial resolution and 0.27 eV energy resolution intuitively identified two coupling plasmons. The in-phase mode redshifted from the ultraviolet region as the inter-particle spacing was reduced, reaching the visible range at 2.7 eV. ...

  15. Electron-spectroscopy study of YbXCu4 (X=Ag,Au,Pd)

    International Nuclear Information System (INIS)

    We have studied the electronic structure of the heavy-electron compounds YbXCu4, with X = Ag,Au,Pd, using x-ray photoemission and bremsstrahlung isochromat spectroscopies. Consistent with other evidence of small Kondo temperatures, we find that Yb in this system is nearly trivalent and that Kondo features in the Yb 4f BIS spectra are either absent or weak

  16. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  17. Electronic excitation processes in rare gas clusters studied by electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    We present the electron energy loss spectra for Ar clusters as a function of incident electron energy and of cluster size. In spectra measured with 100 eV incident electron energy the bulk excitation peak becomes visible for a mean cluster size above 170 atoms per cluster. For 250 eV incident electron energy the bulk excitation peak is clearly observable even for a mean cluster size of 120 atoms per cluster. These experimental results are qualitatively reproduced by a simple calculation that accounts for the mean free path of electrons in Ar clusters; i.e., the penetration depth of incident electrons into the cluster.

  18. Inelastic electron tunneling spectroscopy with a dilution refrigerator based scanning tunneling microscope

    International Nuclear Information System (INIS)

    This paper presents the design and operations of a compact cryogenic scanning tunneling microscope system combined with a dilution refrigerator. We obtained a minimum temperature of 260 mK at the sample position. Taking advantage of low-temperature measurement for the spectroscopy, inelastic electron tunneling spectroscopy (IETS) at 4.4 K was demonstrated for the octanethiol molecules in a self-assembled monolayer. The spectrum showed many vibrational features as in the case of a high-resolution electron energy loss spectroscopy. We discuss the resolution of the IET signals focusing on its changes with the modulation voltage and the sample temperature. IETS at 260 mK is also presented with similar quality as in the case of 4.4 K, indicating that the vibration-dumping methods for the operation of the dilution refrigerator described in this paper are adequate

  19. Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

    International Nuclear Information System (INIS)

    Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U88+ + N2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U28+ with different gases were measured.

  20. Electron-energy-loss spectroscopy and X-ray absorption spectroscopy as complementary probes for complex f-electron metals: cerium and plutonium

    Science.gov (United States)

    Moore, K. T.; Wall, M. A.; Schwartz, A. J.; Chung, B. W.; Morton, S. A.; Tobin, J. G.; Lazar, S.; Tichelaar, F. D.; Zandbergen, H. W.; Söderlind, P.; van der Laan, G.

    2004-04-01

    In this paper, we demonstrate the power of electron-energy-loss spectroscopy (EELS) in a transmission electron microscope by investigating the electron structure of two f-electron metals: Ce and Pu. It is shown that EELS in a transmission electron microscope may be used to circumvent the difficulty of producing single-phase or single-crystal samples owing to its high spatial resolution, and that diffraction patterns and images can be acquired, providing unambiguous phase determination when acquiring spectra. EELS results are supported by synchrotron-radiation-based X-ray absorption, multielectron atomic spectral simulations, and local density approximation calculations based on density-functional theory with the generalized gradient approximation. For Ce, it is shown that changes in {111} stacking sequences can drive substantial modifications in the electronic structure of close-packed phases of Ce that have similar atomic volumes, contrary to previous assumptions in literature. For Pu, it is shown that Russell-Saunders (L-S) coupling fails for the 5f states and that either a j-j or an intermediate scheme must be used for the actinides because of the considerable spin-orbit interaction in the 5f states. We present a model showing how the 5f states behave along the light actinide series.

  1. Far-infra-red molecular vibrational spectroscopy by inelastic electron tunneling

    International Nuclear Information System (INIS)

    In this paper the far infrared vibrational spectrum of polyvinyl-formate is reported as can be obtained by an inelastic electron tunneling experiment. The results here described as compared with those previously known from the current literature show that the afore mentioned technique can improve molecular spectroscopy data both as the covered energy range and resolution

  2. In vivo imaging of a stable paramagnetic probe by pulsed-radiofrequency electron paramagnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Murugesan; Cook; Devasahayam;

    1997-01-01

    Imaging of free radicals by electron paramagnetic resonance (EPR) spectroscopy using time domain acquisition as in nuclear magnetic resonance (NMR) has not been attempted because of the short spin-spin relaxation times, typically under 1 μs, of most biologically relevant paramagnetic species, Rec...

  3. Continuum probe two-dimensional electronic spectroscopy of the photosystem II reaction center

    Directory of Open Access Journals (Sweden)

    Ogilvie J. P.

    2013-03-01

    Full Text Available We report two-dimensional electronic spectroscopy of the photosystem II reaction center, collected in the pump-probe geometry employing a continuum probe. This enables observation of ion bands that report on intermediates in the charge separation process.

  4. Identifying highly conducting Au–C links through inelastic electron tunneling spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Foti, G.; Vázquez, Héctor; Sanchez-Portal, D.; Arnau, A.; Frederiksen, T.

    2014-01-01

    Roč. 118, OCT (2014), s. 27106-27112. ISSN 1932-7447 Institutional support: RVO:68378271 Keywords : molecular electronics * alkanes * tin-functionalization * anchoring groups * vibrational spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.772, year: 2014

  5. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  6. Application of (e,2e) Spectroscopy to the Electronic Structure of Valence Electrons in Crystalline and Amorphous Solids

    OpenAIRE

    Dennison, JR; Ritter, A. L.

    1996-01-01

    This review presents theoretical and experimental aspects of (e,2e) spectroscopy specific to the study of crystalline and amorphous solids. The cross section for (e,2e) scattering is proportional to the spectral momentum density of the ejected electron under certain approximations. The theoretical framework for interpreting (e,2e) measurements is summarized here and general properties of the spectral momentum density of solids are discussed. Different designs of the (e,2e) spectrometer are de...

  7. Radiosterilization dosimetry by electron-spin resonance spectroscopy. Cefotetan

    Energy Technology Data Exchange (ETDEWEB)

    Basly, J.P.; Longy, I. [Laboratoire de Chimie Analytique et Bromatologie, UFR de Pharmacie, Limoges (France); Bernard, M. [Laboratoire de Physique et Biophysique Pharmaceutique, UFR de Pharmacie, Limoges (France)

    1998-02-19

    As an alternative to heat and gas exposure sterilization, ionizing radiation is gaining interest as a sterilization process for medicinal products. Nevertheless, essentially for economic profit, unauthorized and uncontrolled use of radiation processes may be expected. In this context, it is necessary to find methods of distinguishing between irradiated and nonirradiated pharmaceuticals. In the absence of suitable detection methods, our attention was focused on electron-spin resonance (ESR) spectrometry. A third generation cephalosporin, cefotetan, was chosen as a model; this antibiotic is a potential candidate for radiation treatment due to its thermosensitivity. While the ESR spectra of a nonirradiated sample presents no signal, a nonsymmetrical signal, dependent on the irradiation dose, is found in irradiated samples. The number of free radicals was estimated by comparing the second integral from radiosterilized samples and a diphenylpicryl hydrazyl reference. Estimation of the number of free radicals gives 7x10{sup 17} radicals g{sup -1} at 20kGy (1.1x10{sup 16} radicals in 15mg). From this result, the G-value (number of radicals (100eV){sup -1}) could be estimated as 0.6. Decay of radicals upon storage were modeled using a bi-exponential function. The limit of detection of free radicals after irradiation at 25kGy is up to two years. This result agrees with those obtained on other cephalosporins. Aside from qualitative detection, ESR spectrometry can be used for dose estimation. Linear regression is applicable for doses lower than 20kGy. Since the radiation dose selected must always be based upon the bioburden of the products and the degree of sterility required (EN 552 and ANSI/AAMI/ISO 11137), 25kGy could no longer be accepted as a `routine` dose for sterilizing a pharmaceutical. Doses in the 5-20kGy range could be investigated and linear regression appeared to be the least expensive route to follow. The best results for the integration of the curves were

  8. Monitoring of alcoholic fermentation using near infrared and mid infrared spectroscopies combined with electronic nose and electronic tongue

    Energy Technology Data Exchange (ETDEWEB)

    Buratti, S., E-mail: susanna.buratti@unimi.it [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy); Ballabio, D. [Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano (Italy); Giovanelli, G. [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy); Dominguez, C.M. Zuluanga [Instituto de Ciencia y Tecnologia de Alimentos, Universidad Nacional de Colombia, Ciudad Universitaria, Bogota (Colombia); Moles, A.; Benedetti, S.; Sinelli, N. [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy)

    2011-07-04

    Graphical abstract: Application of non destructive methods for the monitoring of red wine fermentation in correlation with the evolution of chemical parameters. Highlights: > We monitored time-related changes in red wine fermentation process. > NIR and MIR spectroscopies, electronic nose and tongue were applied. > Data were kinetically modelled to identify critical points during fermentation. > NIR, MIR electronic nose and tongue were able to follow the fermentation process. > The models agreed with the evolution of chemical parameters. - Abstract: Effective fermentation monitoring is a growing need due to the rapid pace of change in the wine industry, which calls for fast methods providing real time information in order to assure the quality of the final product. The objective of this work is to investigate the potential of non-destructive techniques associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Eight micro-fermentation trials conducted in the Valtellina region (Northern Italy) during the 2009 vintage, were monitored by a FT-NIR and a FT-IR spectrometer and by an electronic nose and tongue. The spectroscopic technique was used to investigate molecular changes, while electronic nose and electronic tongue evaluated the evolution of the aroma and taste profile during the must-wine fermentation. Must-wine samples were also analysed by traditional chemical methods in order to determine sugars (glucose and fructose) consumption and alcohol (ethanol and glycerol) production. Principal Component Analysis was applied to spectral, electronic nose and electronic tongue data, as an exploratory tool, to uncover molecular, aroma and taste modifications during the fermentation process. Furthermore, the chemical data and the PC1 scores from spectral, electronic nose and electronic tongue data were modelled as a function of time to identify critical points during fermentation. The results showed that NIR and MIR

  9. Monitoring of alcoholic fermentation using near infrared and mid infrared spectroscopies combined with electronic nose and electronic tongue

    International Nuclear Information System (INIS)

    Graphical abstract: Application of non destructive methods for the monitoring of red wine fermentation in correlation with the evolution of chemical parameters. Highlights: → We monitored time-related changes in red wine fermentation process. → NIR and MIR spectroscopies, electronic nose and tongue were applied. → Data were kinetically modelled to identify critical points during fermentation. → NIR, MIR electronic nose and tongue were able to follow the fermentation process. → The models agreed with the evolution of chemical parameters. - Abstract: Effective fermentation monitoring is a growing need due to the rapid pace of change in the wine industry, which calls for fast methods providing real time information in order to assure the quality of the final product. The objective of this work is to investigate the potential of non-destructive techniques associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Eight micro-fermentation trials conducted in the Valtellina region (Northern Italy) during the 2009 vintage, were monitored by a FT-NIR and a FT-IR spectrometer and by an electronic nose and tongue. The spectroscopic technique was used to investigate molecular changes, while electronic nose and electronic tongue evaluated the evolution of the aroma and taste profile during the must-wine fermentation. Must-wine samples were also analysed by traditional chemical methods in order to determine sugars (glucose and fructose) consumption and alcohol (ethanol and glycerol) production. Principal Component Analysis was applied to spectral, electronic nose and electronic tongue data, as an exploratory tool, to uncover molecular, aroma and taste modifications during the fermentation process. Furthermore, the chemical data and the PC1 scores from spectral, electronic nose and electronic tongue data were modelled as a function of time to identify critical points during fermentation. The results showed that

  10. Development of the web-based NIST X-ray Photoelectron Spectroscopy (XPS) Database

    OpenAIRE

    Angela Y. Lee; Blakeslee, Dorothy M; Powell, Cedric J; Rumble, Jr., John

    2006-01-01

    The first Web-based version of the NIST X-ray Photoelectron Spectroscopy Database (XPSDB) is described. The current database, built from a relational database management system (RDBMS), contains critically evaluated data with over 19,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines. It is available free of charge to the public through the Internet at http://srdata.nist.gov/xps/.

  11. Real time tracing of valence-shell electronic coherences with attosecond transient absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, A. [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany); Santra, R. [Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg (Germany); Department of Physics, University of Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany); Goulielmakis, E., E-mail: elgo@mpq.mpg.de [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany)

    2013-03-12

    Highlights: ► Detailing the technique of attosecond transient absorption spectroscopy. ► Tracing the charge state time-resolved ionization of atoms. ► Real-time observation and reconstruction of valence electron motion in Kr{sup +} ions. ► Observation of coherences in correlated multi-hole systems: Kr{sup 2+} and xenon ions. - Abstract: The chemical properties of atoms, molecules and of more complex systems such as clusters, nanoparticles or condensed matter systems are determined by valence electrons. Real-time control of these properties requires the capability of tracing as well as of driving valence electrons on their native temporal scale of motion, that is, within tens to thousands of attoseconds. Here we detail the technique of attosecond transient absorption spectroscopy. It combines the extreme sensitivity of core-level spectroscopy with the unprecedented temporal resolution offered by the tools of attosecond technology. We use the technique to demonstrate real-time tracing and complete characterization of coherent electron motion triggered by single, double or multiple ionization of atoms exposed to intense, few-cycle pulses. Our work opens the door to high fidelity, time-domain studies and control of electron dynamics in the microcosm.

  12. Electron energy-loss spectroscopy of quasi-one-dimensional cuprates and vanadates

    International Nuclear Information System (INIS)

    In a combination of experimental and theoretical methods in this thesis the electronic structures of quasi-one-dimensional cuprates and vanadates were studied. For this the momentum-dependent loss function was measured by means of the electron energy-loss spectroscopy in transmission on monocrystals of Li2CuO2, CuGeO3, V2O5 and α'-NaVO5. The comparison of the experimental data with results from band-structure and cluster calculations allowed conclusions on the mobility and correlations of the electrons in these systems

  13. Radiation damage in tripalmitin layers studied by means of infrared spectroscopy and electron microscopy

    International Nuclear Information System (INIS)

    Structural deteriorations in biomembranes, as inevitably induced while structural information is gathered by electron optical methods, were evaluated by infrared spectroscopy. Tripalmitin model membranes were irradiated with 100 keV-electrons in an electron microscope. The intensity decay of group vibrations over the dose reveals the sequence of damage in the polar and nonpolar part of the molecule. The C-C backbone, being the most important structural feature, shows a significant latency effect up to 0.6 e-/A2 and is completely disordered by 3 e-/A2, corresponding to about three inelastic processes per molecule

  14. SOR-RING: an electron storage ring dedicated to spectroscopy, 1

    International Nuclear Information System (INIS)

    An electron storage ring dedicated to the vacuum ultraviolet spectroscopy in the wavelength region above 40 A has been designed. The ring is expected to operate at 300 MeV and 100 mA. Electrons with the energy of 300 MeV are extracted from a 1.3 GeV electron synchrotron at Institute for Nuclear Study(INS) and injected into the ring. The ring is essentially a weak focusing machine with an adjustable operating point. Various parameters of the ring are shown. The design principle is described in connection with the important parts of the ring. (auth.)

  15. Development of Holmium-163 Electron-Capture Spectroscopy with Transition-Edge Sensors

    Science.gov (United States)

    Croce, M. P.; Rabin, M. W.; Mocko, V.; Kunde, G. J.; Birnbaum, E. R.; Bond, E. M.; Engle, J. W.; Hoover, A. S.; Nortier, F. M.; Pollington, A. D.; Taylor, W. A.; Weisse-Bernstein, N. R.; Wolfsberg, L. E.; Hays-Wehle, J. P.; Schmidt, D. R.; Swetz, D. S.; Ullom, J. N.; Barnhart, T. E.; Nickles, R. J.

    2016-08-01

    Calorimetric decay energy spectroscopy of electron-capture-decaying isotopes is a promising method to achieve the sensitivity required for electron neutrino mass measurement. The very low total nuclear decay energy (Q_EC based isotope production, isolation, and purification of ^{163}Ho. We have developed transition-edge sensors for this measurement and methods for incorporating ^{163}Ho into high-resolution microcalorimeters, and have measured the electron-capture spectrum of ^{163}Ho. We present our work in these areas and discuss the measured spectrum and its comparison to current theory.

  16. High-harmonic transient grating spectroscopy of NO2 electronic relaxation

    CERN Document Server

    Ruf, H; Ferré, A; Thiré, N; Bertrand, J B; Bonnet, L; Cireasa, R; Constant, E; Corkum, P B; Descamps, D; Fabre, B; Larregaray, P; Mével, E; Petit, S; Pons, B; Staedter, D; Wörner, H J; Villeneuve, D M; Mairesse, Y; Halvick, P; Blanchet, V

    2012-01-01

    We study theoretically and experimentally the electronic relaxation of NO2 molecules excited by absorption of one ~400 nm pump photon. Semi-classical simulations based on trajectory surface hopping calculations are performed. They predict fast oscillations of the electronic character around the intersection of the ground and first excited diabatic states. An experiment based on high-order harmonic transient grating spectroscopy reveals dynamics occuring on the same timescale. A systematic study of the detected transient is conducted to investigate the possible influence of the pump intensity, pump wavelength, and rotational temperature of the molecules. The quantitative agreement between measured and predicted dynamics shows that, in NO2, high harmonic transient grating spectroscopy encodes vibrational dynamics underlying the electronic relaxation.

  17. Electron momentum spectroscopy of aniline taking account of nuclear dynamics in the initial electronic ground state

    Science.gov (United States)

    Farasat, M.; Shojaei, S. H. R.; Morini, F.; Golzan, M. M.; Deleuze, M. S.

    2016-04-01

    The electronic structure, electron binding energy spectrum and (e, 2e) momentum distributions of aniline have been theoretically predicted at an electron impact energy of 1.500 keV on the basis of Born-Oppenheimer molecular dynamical simulations, in order to account for thermally induced nuclear motions in the initial electronic ground state. Most computed momentum profiles are rather insensitive to thermally induced alterations of the molecular structure, with the exception of the profiles corresponding to two ionization bands at electron binding energies comprised between ˜10.0 and ˜12.0 eV (band C) and between ˜16.5 and ˜20.0 eV (band G). These profiles are found to be strongly influenced by nuclear dynamics in the electronic ground state, especially in the low momentum region. The obtained results show that thermal averaging smears out most generally the spectral fingerprints that are induced by nitrogen inversion.

  18. Electron spectroscopy at the high-energy endpoint of electron-nucleus bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Hillenbrand, Pierre-Michel [GSI Darmstadt (Germany); Univ. Giessen (Germany); Hagmann, Siegbert [GSI Darmstadt (Germany); Univ. Frankfurt (Germany); Banas, Dariusz [Univ. Kielce (Poland); Brandau, Carsten [Extreme Matter Institute Darmstadt (Germany); Univ. Giessen (Germany); Doerner, Reinhard [Univ. Frankfurt (Germany); De Filippo, Enrico [INFN Catania (Italy); Gumberidze, Alexandre [Extreme Matter Institute Darmstadt (Germany); Guo, Dalong [IMP Lanzhou (China); Univ. Beijing (China); Jakubassa-Amundsen, Doris [Univ. Muenchen (Germany); Lestinsky, Michael; Spillmann, Uwe [GSI Darmstadt (Germany); Litvinov, Yuri [GSI Darmstadt (Germany); Univ. Heidelberg (Germany); Mueller, Alfred; Schippers, Stefan [Univ. Giessen (Germany); Rothard, Hermann [CIRIL GANIL Caen (France); Surzhykov, Andrey [Helmholtz-Institut Jena (Germany); Trotsenko, Sergey [GSI Darmstadt (Germany); Helmholtz-Institut Jena (Germany); Voitkiv, Alexander [MPI-K Heidelberg (Germany); Yerokhin, Vladimir [Petersburg State Univ. (Russian Federation); Stoehlker, Thomas [GSI Darmstadt (Germany); Helmholtz-Institut Jena (Germany); Univ. Jena (Germany)

    2014-07-01

    The high-energy endpoint of electron-nucleus bremsstrahlung has been studied in inverse kinematics: For collisions U{sup 88+}+N{sub 2} → U{sup 88+}+[N{sub 2}{sup +}]{sup *} + e{sup -} + γ the energy distribution of electrons scattered under θ{sub e}{sup lab} = 0 {sup circle} with v{sub e} ∼ v{sub proj} was measured coincident with the bremsstrahlung photons emitted under various angles θ{sub γ}{sup lab}. The triple-differential cross sections provide a stringent test for the fully relativistic theory of electron-nucleus bremsstrahlung. Furthermore the studied process, also termed radiative electron capture to continuum RECC, was compared to the competing processes of non-radiative electron capture to continuum ECC and the electron loss to continuum ELC.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  1. Electron energy loss spectroscopy in a crystalline environment using inner shell ionization

    International Nuclear Information System (INIS)

    A theory for electron energy loss spectroscopy is presented. The focus is on inner shell ionization in a crystalline environment under dynamical electron diffraction conditions which includes dechanneling due to inelastic scattering and in particular to thermal diffuse scattering (TDS). It incorporates ionization kinematics and the associated localization of the interaction from first principles. Appropriate integration over the possible final states of the detected scattered fast electron as well as the ejected target electron is catered for. The theory accounts for ionization by the dechanneled thermally scattered electrons as well as delocalization due to thermal fluctuations in target atom position. This formulation extends previous work which did not explicitly incorporate inelastic scattering into the ionization cross section. The dependence of the EELS cross section on the orientation, thickness and temperature of the specimen will be discussed. Also the influence of incident energy, energy window for the detected energy loss electrons and the acceptance angle of the detector on the cross section will be considered. In a simpler version of the formalism given here, with channeling limited to the incident electron, was successfully applied to energy dispersive x-ray emission spectroscopy and the related technique of atom location by channeling enhanced microanalysis. It is shown in this paper that this simplification is reasonable for EELS under suitable experimental conditions. 34 refs., 5 figs

  2. Time-and-energy-resolved measurement of Auger cascades following Kr 3d excitation by attosecond pulses

    International Nuclear Information System (INIS)

    We show that attosecond metrology has evolved from proof-of-principle experiments to a level where complex processes can be resolved in time that cannot be accessed using any other existing technique. The cascaded Auger decay following ionization and excitation of the 3d-subshell in Kr with subfemtosecond 94 eV soft x-ray pulses has been energy- and time-resolved in an x-ray pump-infrared probe experiment. This Auger cascade reveals rich multi-electron dynamics, which despite the fact that there are many experimental and theoretical data available, is not yet fully understood. We present time-resolved data showing the sequence of the temporal dynamics in the cascaded Auger decay. The decay time of several groups of lines has been measured, including the lines at the low-energy part of the spectrum, which are predominantly produced by the second-step Auger transitions. Our experimental data reveal long lifetimes (up to 70 fs) of the subvalence excited ionic (intermediate) states in the cascaded resonant Auger decay. Extensive theoretical calculations within the multiconfiguration Dirac-Fock (MCDF) approach show that the observed long lifetime may be attributed to the second-step Auger decay of the resonantly excited 3d-1np states with n = 6,7. Furthermore, our experimental data show that the electrons with a kinetic energy around 25 eV (generally assigned as M4,5N1N1 1S0 normal Auger lines) have a component corresponding to the second-step Auger decay of the ion after resonant Auger transition 3d-1np → 4s2 4p3 4dnp → 4s2 4p4 with a lifetime of 26 ± 4 fs. (paper)

  3. Measuring correlated electronic and vibrational spectral dynamics using line shapes in two-dimensional electronic-vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Nicholas H. C.; Dong, Hui; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

    2015-05-07

    Two-dimensional electronic-vibrational (2DEV) spectroscopy is an experimental technique that shows great promise in its ability to provide detailed information concerning the interactions between the electronic and vibrational degrees of freedom in molecular systems. The physical quantities 2DEV is particularly suited for measuring have not yet been fully determined, nor how these effects manifest in the spectra. In this work, we investigate the use of the center line slope of a peak in a 2DEV spectrum as a measure of both the dynamic and static correlations between the electronic and vibrational states of a dye molecule in solution. We show how this center line slope is directly related to the solvation correlation function for the vibrational degrees of freedom. We also demonstrate how the strength with which the vibration on the electronic excited state couples to its bath can be extracted from a set of 2DEV spectra. These analytical techniques are then applied to experimental data from the laser dye 3,3′-diethylthiatricarbocyanine iodide in deuterated chloroform, where we determine the lifetime of the correlation between the electronic transition frequency and the transition frequency for the backbone C = C stretch mode to be ∼1.7 ps. Furthermore, we find that on the electronic excited state, this mode couples to the bath ∼1.5 times more strongly than on the electronic ground state.

  4. Measuring correlated electronic and vibrational spectral dynamics using line shapes in two-dimensional electronic-vibrational spectroscopy.

    Science.gov (United States)

    Lewis, Nicholas H C; Dong, Hui; Oliver, Thomas A A; Fleming, Graham R

    2015-05-01

    Two-dimensional electronic-vibrational (2DEV) spectroscopy is an experimental technique that shows great promise in its ability to provide detailed information concerning the interactions between the electronic and vibrational degrees of freedom in molecular systems. The physical quantities 2DEV is particularly suited for measuring have not yet been fully determined, nor how these effects manifest in the spectra. In this work, we investigate the use of the center line slope of a peak in a 2DEV spectrum as a measure of both the dynamic and static correlations between the electronic and vibrational states of a dye molecule in solution. We show how this center line slope is directly related to the solvation correlation function for the vibrational degrees of freedom. We also demonstrate how the strength with which the vibration on the electronic excited state couples to its bath can be extracted from a set of 2DEV spectra. These analytical techniques are then applied to experimental data from the laser dye 3,3'-diethylthiatricarbocyanine iodide in deuterated chloroform, where we determine the lifetime of the correlation between the electronic transition frequency and the transition frequency for the backbone C = C stretch mode to be ∼1.7 ps. Furthermore, we find that on the electronic excited state, this mode couples to the bath ∼1.5 times more strongly than on the electronic ground state. PMID:25956093

  5. Real-Time Probing of Electron Dynamics Using Attosecond Time-Resolved Spectroscopy

    Science.gov (United States)

    Ramasesha, Krupa; Leone, Stephen R.; Neumark, Daniel M.

    2016-05-01

    Attosecond science has paved the way for direct probing of electron dynamics in gases and solids. This review provides an overview of recent attosecond measurements, focusing on the wealth of knowledge obtained by the application of isolated attosecond pulses in studying dynamics in gases and solid-state systems. Attosecond photoelectron and photoion measurements in atoms reveal strong-field tunneling ionization and a delay in the photoemission from different electronic states. These measurements applied to molecules have shed light on ultrafast intramolecular charge migration. Similar approaches are used to understand photoemission processes from core and delocalized electronic states in metal surfaces. Attosecond transient absorption spectroscopy is used to follow the real-time motion of valence electrons and to measure the lifetimes of autoionizing channels in atoms. In solids, it provides the first measurements of bulk electron dynamics, revealing important phenomena such as the timescales governing the switching from an insulator to a metallic state and carrier-carrier interactions.

  6. Electron energy-loss spectroscopy study of thin film hafnium aluminates for novel gate dielectrics.

    Science.gov (United States)

    Stemmer, S; Chen, Z Q; Zhu, W J; Ma, T P

    2003-04-01

    We have used conventional high-resolution transmission electron microscopy and electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopy to investigate the microstructure and electronic structure of hafnia-based thin films doped with small amounts (6.8 at.%) of Al grown on (001) Si. The as-deposited film is amorphous with a very thin (approximately 0.5 nm) interfacial SiOx layer. The film partially crystallizes after annealing at 700 degrees C and the interfacial SiO2-like layer increases in thickness by oxygen diffusion through the Hf-aluminate layer and oxidation of the silicon substrate. Oxygen K-edge EELS fine-structures are analysed for both films and interpreted in the context of the films' microstructure. We also discuss valence electron energy-loss spectra of these ultrathin films. PMID:12694419

  7. Real-Time Probing of Electron Dynamics Using Attosecond Time-Resolved Spectroscopy.

    Science.gov (United States)

    Ramasesha, Krupa; Leone, Stephen R; Neumark, Daniel M

    2016-05-27

    Attosecond science has paved the way for direct probing of electron dynamics in gases and solids. This review provides an overview of recent attosecond measurements, focusing on the wealth of knowledge obtained by the application of isolated attosecond pulses in studying dynamics in gases and solid-state systems. Attosecond photoelectron and photoion measurements in atoms reveal strong-field tunneling ionization and a delay in the photoemission from different electronic states. These measurements applied to molecules have shed light on ultrafast intramolecular charge migration. Similar approaches are used to understand photoemission processes from core and delocalized electronic states in metal surfaces. Attosecond transient absorption spectroscopy is used to follow the real-time motion of valence electrons and to measure the lifetimes of autoionizing channels in atoms. In solids, it provides the first measurements of bulk electron dynamics, revealing important phenomena such as the timescales governing the switching from an insulator to a metallic state and carrier-carrier interactions. PMID:26980312

  8. Electron spectroscopy of He and NO using electron impact and multiphoton ionisation

    International Nuclear Information System (INIS)

    This thesis describes two experimental studies which are intended to contribute to our knowledge of the structure of molecules and the decay dynamics of excited molecular states. The two studies have in common that they are both concerned with ionisation processes, in which an accurately known amount of energy is transferred to the target, and energy analysis of the ejected electrons is made. Ionisation is caused either by scattering electrons off the molecules (chapter 2: electron impact ionisation) or by a simultaneous absorption of several photons (chapter 3: multiphoton ionisation). In chapter 2 an electron impact ionisation experiment on Helium is described in which the kinematics of both the scattered and the ejected electrons is fully determined ((e,2e) experiment). (Auth.)

  9. A Complete Overhaul of the Electron Energy-Loss Spectroscopy and X-Ray Absorption Spectroscopy Database: eelsdb.eu.

    Science.gov (United States)

    Ewels, Philip; Sikora, Thierry; Serin, Virginie; Ewels, Chris P; Lajaunie, Luc

    2016-06-01

    The electron energy-loss spectroscopy (EELS) and X-ray absorption spectroscopy (XAS) database has been completely rewritten, with an improved design, user interface, and a number of new tools. The database is accessible at https://eelsdb.eu/ and can now be used without registration. The submission process has been streamlined to encourage spectrum submissions and the new design gives greater emphasis on contributors' original work by highlighting their papers. With numerous new filters and a powerful search function, it is now simple to explore the database of several hundred EELS and XAS spectra. Interactive plots allow spectra to be overlaid, facilitating online comparison. An application-programming interface has been created, allowing external tools and software to easily access the information held within the database. In addition to the database itself, users can post and manage job adverts and read the latest news and events regarding the EELS and XAS communities. In accordance with the ongoing drive toward open access data increasingly demanded by funding bodies, the database will facilitate open access data sharing of EELS and XAS spectra. PMID:26899024

  10. Two-dimensional electronic spectroscopy and photosynthesis: Fundamentals and applications to photosynthetic light-harvesting

    International Nuclear Information System (INIS)

    Graphical abstract: 2D electronic spectroscopy, when combined with theoretical approaches, can investigate structure-function relationships in photosynthetic complexes by probing electronic energy transfer and excited state orientations. Display Omitted Highlights: → We review theoretical principles and experimental implementation of 2D spectroscopy. → 2DES monitors energy transfer, observes coherence, determines excited state geometry, and compares to homology models. → 2DES reveals structure-function relationships in the Photosystem II supercomplex. - Abstract: In natural light harvesting systems, pigment-protein complexes are able to harvest sunlight with near unity quantum efficiency. These complexes exhibit emergent properties that cannot be simply extrapolated from knowledge of their component parts. In this perspective, we focus on how two-dimensional electronic spectroscopy (2DES) can provide an incisive tool to probe the electronic, energetic, and spatial landscapes that must be understood to describe photosynthetic light-harvesting. We review the theoretical and experimental principles of 2DES, and demonstrate its application to the study of the Photosystem II supercomplex of green plants. We illustrate several capabilities of 2DES, including monitoring energy transfer pathways, observing excitonic coherence, determining excitonic geometry, and informing on the atomic structure.

  11. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Science.gov (United States)

    Dahlberg, Peter D.; Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S.

    2015-09-01

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ˜40-60 fs.

  12. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    International Nuclear Information System (INIS)

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs

  13. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-09-14

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850{sup ∗} states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs.

  14. Enhanced radiative Auger emission from lithiumlike 20Ca17+

    International Nuclear Information System (INIS)

    Radiative Auger emission (RAE) from lithiumlike 20Ca17+ 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 lithiumlike 16S13+ and 23V20+ and indicates a systematic dependence on Z. Both the enhancement and the relative RAE transition rate increase with Z. (orig.)

  15. Enhanced radiative Auger emission from lithiumlike 16S13+

    International Nuclear Information System (INIS)

    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

  16. Electronic structure of an aluminium oxide film as studied by (e, 2e) spectroscopy)

    International Nuclear Information System (INIS)

    We report here on our recent investigations on electronic structure of an aluminium oxide layer on polycrystalline film by (e, 2e) spectroscopy. The (e, 2e) spectroscopy, a new spectroscopic technique, can measure real electron momentum directly and visualize the dispersion relation between energy and momentum of electrons in solids. The (e, 2e) spectrometer in this experiment has been set up at non coplanar asymmetric geometry. The incident electron energy is 20keV. The two outgoing electrons have energies of 18.8 keV and 1.2 keV, and are measured with two electron analysers each measuring simultaneously a range of angles and energies at polar angles of 14 degree and 76 degree respectively. With this kinematics the spectrometer is surface sensitive to about 2nm layer on the sample and has an overall measurable energy range of 56 eV with a resolution of 1.0 eV and momentum range from -3.5 to 3.5 a.u. with a resolution of 0.15 a.u. A count rate of 35 (e, 2e) coincidence counts per minute was achieved

  17. Detection of Nitric Oxide by Electron Paramagnetic Resonance Spectroscopy: Spin-Trapping with Iron-Dithiocarbamates.

    Science.gov (United States)

    Maia, Luisa B; Moura, José J G

    2016-01-01

    Electron paramagnetic resonance (EPR) spectroscopy is the ideal methodology to identify radicals (detection and characterization of molecular structure) and to study their kinetics, in both simple and complex biological systems. The very low concentration and short life-time of NO and of many other radicals do not favor its direct detection and spin-traps are needed to produce a new and persistent radical that can be subsequently detected by EPR spectroscopy.In this chapter, we present the basic concepts of EPR spectroscopy and of some spin-trapping methodologies to study NO. The "strengths and weaknesses" of iron-dithiocarbamates utilization, the NO traps of choice for the authors, are thoroughly discussed and a detailed description of the method to quantify the NO formation by molybdoenzymes is provided. PMID:27094413

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

    Science.gov (United States)

    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

  19. The calibration of spectrometers for Auger electron and X-ray photoelectron spectrometers part II - the determination of the electron spectrometer transmission function and the detector sensitivity energy dependencies

    International Nuclear Information System (INIS)

    For the use of published general or theoretical sensitivity factors in quantitative AES and XPS the energy dependence of both the spectrometer transmission function and the detector sensitivity must be known. Here we develop simple procedures which allow these dependencies to be determined experimentally. Detailed measurements for a modified VG Scientific ESCALAB II, the metrology spectrometer, operated in both the constant ΔE/E and constant ΔE modes, are presented and compared with theoretical estimates. It is shown that an exceptionally detailed electron-optical calculation, involving proprietary information, would be required to match the accuracy of the experimental procedures developed. Removal of the spectrometer transmission function and the detector sensitivity terms allows the measured spectrum to be converted to the true electron emission spectrum irrespective of the mode of operation. This provides the first step to the provision of reference samples to calibrate the transmission functions and detector sensitivities of all instruments so that they, in turn, may produce true electron emission spectra. This is vital if (i) all instruments are to give consistent results, (ii) theoretical terms are to be used in quantifying either AES or XPS and (iii) reference data banks are to be established for AES or XPS

  20. Auger neutralization and ionization in grazing ion-surface interaction

    Energy Technology Data Exchange (ETDEWEB)

    Zimny, R. (Inst. of Nuclear Physics, Univ. Muenster (Germany)); Miskovic, Z.L. (Boris Kidric Inst. of Nuclear Sciences, Belgrade (Yugoslavia))

    1991-06-01

    The effect of the projectile velocity parallel to the surface v{sub parallel} on Auger-type neutralization and ionization processes during grazing scattering of atomic particles from surfaces will be discussed. It is found that, contrary to the static case (v{sub parallel}=0), under grazing collision the Auger-type electron exchange between the metallic conduction band and an atomic orbital is a two-way process: atomic particles may be neutralized, as well as ionized. In particular, two types of v{sub parallel} dependence are obtained: (1) a gradual decrease of the final atomic level population with increasing v{sub parallel} in the case of atomic levels below the Fermi level E{sub F}, and (2) a peak-shaped v{sub parallel} dependence for atomic levels above E{sub F}. The leading features of these basic electron-exchange mechanisms between atoms and surfaces are illustrated for various atomic quasi-one-electron systems scattered from silver and magnesium surfaces. (orig.).

  1. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    International Nuclear Information System (INIS)

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc18+ yield a high-precision measurement of the 2s-2p3/2 transition energy in this system. Operation of the two-electron-beam setup at high collision energy (∼1000 eV) is established using resonances of hydrogenlike Mg11+, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F6+. (orig.)

  2. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

  3. Analysis of catalytic gas products using electron energy-loss spectroscopy and residual gas analysis for operando transmission electron microscopy.

    Science.gov (United States)

    Miller, Benjamin K; Crozier, Peter A

    2014-06-01

    Operando transmission electron microscopy (TEM) of catalytic reactions requires that the gas composition inside the TEM be known during the in situ reaction. Two techniques for measuring gas composition inside the environmental TEM are described and compared here. First, electron energy-loss spectroscopy, both in the low-loss and core-loss regions of the spectrum was utilized. The data were quantified using a linear combination of reference spectra from individual gasses to fit a mixture spectrum. Mass spectrometry using a residual gas analyzer was also used to quantify the gas inside the environmental cell. Both electron energy-loss spectroscopy and residual gas analysis were applied simultaneously to a known 50/50 mixture of CO and CO2, so the results from the two techniques could be compared and evaluated. An operando TEM experiment was performed using a Ru catalyst supported on silica spheres and loaded into the TEM on a specially developed porous pellet TEM sample. Both techniques were used to monitor the conversion of CO to CO2 over the catalyst, while simultaneous atomic resolution imaging of the catalyst was performed. PMID:24815065

  4. In situ light spectroscopy in the environmental transmission electron microscope (ETEM)

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Langhammer, C.; Pedersen, Thomas;

    2012-01-01

    sensing (INPS) [5] in an ETEM using a unique platform that allows simultaneous TEM imaging and optical spectroscopy under the same conditions. TEM and INPS work in a synergistic way since TEM is able to probe matter on a local scale and INPS is a spectroscopic technique that collects and integrates......Photocatalysts are of fundamental interest for sustainable energy research [1]. By means of transmission electron microscopy (TEM), insight into the structure and composition can be obtained and used for their further optimization [2]. Here, we combine conventional TEM analysis on photocatalysts...... with several in situ TEM techniques including environmental transmission electron microscopy (ETEM) [3,4], in situ photo activation and localized surface plasmon resonance (LSPR) spectroscopy [5,6]. ETEM is a well-established technique for material analysis. In this work we implement indirect nanoplasmonic...

  5. Direct observation of multistep energy transfer in LHCII with fifth-order 3D electronic spectroscopy

    Science.gov (United States)

    Zhang, Zhengyang; Lambrev, Petar H.; Wells, Kym L.; Garab, Győző; Tan, Howe-Siang

    2015-07-01

    During photosynthesis, sunlight is efficiently captured by light-harvesting complexes, and the excitation energy is then funneled towards the reaction centre. These photosynthetic excitation energy transfer (EET) pathways are complex and proceed in a multistep fashion. Ultrafast two-dimensional electronic spectroscopy (2DES) is an important tool to study EET processes in photosynthetic complexes. However, the multistep EET processes can only be indirectly inferred by correlating different cross peaks from a series of 2DES spectra. Here we directly observe multistep EET processes in LHCII using ultrafast fifth-order three-dimensional electronic spectroscopy (3DES). We measure cross peaks in 3DES spectra of LHCII that directly indicate energy transfer from excitons in the chlorophyll b (Chl b) manifold to the low-energy level chlorophyll a (Chl a) via mid-level Chl a energy states. This new spectroscopic technique allows scientists to move a step towards mapping the complete complex EET processes in photosynthetic systems.

  6. Terahertz magneto-optical spectroscopy of two-dimensional hole and electron systems

    CERN Document Server

    Kamaraju, N; Ekenberg, U; Gvozdić, D M; Boubanga-Tombet, S; Upadhya, P C; Reno, J; Taylor, A J; Prasankumar, R P

    2014-01-01

    We have used terahertz (THz) magneto-optical spectroscopy to investigate the cyclotron resonance in high mobility two-dimensional electron and hole systems. Our experiments reveal long-lived (~20 ps) coherent oscillations in the measured signal in the presence of a perpendicular magnetic field. The cyclotron frequency extracted from the oscillations varies linearly with magnetic field for a two-dimensional electron gas (2DEG), as expected. However, we find that the complex non-parabolic valence band structure in a two-dimensional hole gas (2DHG) causes the cyclotron frequency and effective mass to vary nonlinearly with the magnetic field, as verified by multiband Landau level calculations. This is the first time that THz magneto-optical spectroscopy has been used to study 2DHG, and we expect that these results will motivate further studies of these unique 2D nanosystems.

  7. Free electrons and ionic liquids: study of excited states by means of electron-energy loss spectroscopy and the density functional theory multireference configuration interaction method

    OpenAIRE

    Regeta, Khrystyna; Bannwarth, Christoph; Grimme, Stefan; Allan, Michael

    2015-01-01

    The technique of low energy (0–30 eV) electron impact spectroscopy, originally developed for gas phase molecules, is applied to room temperature ionic liquids (IL). Electron energy loss (EEL) spectra recorded near threshold, by collecting 0–2 eV electrons, are largely continuous, assigned to excitation of a quasi-continuum of high overtones and combination vibrations of low-frequency modes. EEL spectra recorded by collecting 10 eV electrons show predominantly discrete vibrational and electron...

  8. Techniques and Application of Electron Spectroscopy Based on Novel X-ray Sources

    OpenAIRE

    Plogmaker, Stefan

    2012-01-01

    The curiosity of researchers to find novel characteristics and properties of matter constantly pushes for the development of instrumentation based on X-radiation. I present in this thesis techniques for electron spectroscopy based on developments of X-ray sources both in time structure and energy. One part describes a laser driven High-Harmonic Generation source and the application of an off-plane grating monochromator with additional beamlines and spectrometers. In initial experiments, the s...

  9. Electron paramagnetic resonance and Raman spectroscopy studies on carbon-doped

    OpenAIRE

    Bateni, Ali; Somer, Mehmet Suat; Erdem, Emre; Repp, Sergej; Acar, SelÇuk; Kokal, İlkin; Haessler, Wolfgang; Weber, Stefan

    2015-01-01

    Undoped and carbon-doped magnesium diboride (MgB2) samples were synthesized using two sets of mixtures prepared from the precursors, amorphous nanoboron, and as-received amorphous carbon-doped nanoboron. The microscopic defect structures of carbon-doped MgB2 samples were systematically investigated using X-ray powder diffraction, Raman and electron paramagnetic resonance spectroscopy. Mg vacancies and C-related dangling-bond active centers could be distinguished, and sp(3)-hybridized carbon r...

  10. Transformation optics: a time- and frequency-domain analysis of electron-energy loss spectroscopy

    OpenAIRE

    Kraft, Matthias; Luo, Yu; Pendry, J. B.

    2016-01-01

    Electron energy loss spectroscopy (EELS) and Cathodoluminescence (CL) play a pivotal role in many of the cutting edge experiments in plasmonics. EELS and CL experiments are usually supported by numerical simulations, which, whilst accurate, may not provide as much physical insight as analytical calculations do. Fully analytical solutions to EELS and CL systems in plasmonics are rare and difficult to obtain. This paper aims to narrow this gap by introducing a new method based on Transformation...

  11. Superatom spectroscopy and the electronic state correlation between elements and isoelectronic molecular counterparts

    OpenAIRE

    Peppernick, Samuel J.; Gunaratne, K.D. Dasitha; Castleman, A. W.

    2009-01-01

    Detailed in the present investigation are results pertaining to the photoelectron spectroscopy of negatively charged atomic ions and their isoelectronic molecular counterparts. Experiments utilizing the photoelectron imaging technique are performed on the negative ions of the group 10 noble metal block (i.e. Ni-, Pd-, and Pt-) of the periodic table at a photon energy of 2.33 eV (532 nm). The accessible electronic transitions, term energies, and orbital angular momentum components of the bound...

  12. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    OpenAIRE

    Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.

    2014-01-01

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at fr...

  13. Simulation of inelastic electron tunneling spectroscopy of single molecules with functionalized tips

    OpenAIRE

    García-Lekue, Aran; Sánchez-Portal, Daniel; Arnau, Andrés; Frederiksen, T.

    2011-01-01

    The role of the tip in inelastic electron tunneling spectroscopy (IETS) performed with scanning tunneling microscopes (STM) is theoretically addressed via first-principles simulations of vibrational spectra of single carbon monoxide (CO) molecules adsorbed on Cu(111). We show how chemically functionalized STM tips modify the IETS intensity corresponding to adsorbate modes on the sample side. The underlying propensity rules are explained using symmetry considerations for both the vibrational m...

  14. Electron Spin Resonance Spectroscopy: Application to Proof of Structure of Organic Ketones.

    Science.gov (United States)

    Russell, G A; Talaty, E R

    1965-05-28

    Many ketones containing an alpha-methylene group can be converted to alpha-diketone radical anions in dimethyl sulfoxide solution. The resulting radical anions can usually be unambiguously identified by electron spin resonance spectroscopy, and the structure of the starting ketone may be deduced, often without reference to model compounds. The technique is also applicable to alpha-diketones, alpha-bromoketones, and alpha-hydroxyketones. PMID:17748118

  15. Two-dimensional electronic spectroscopy for the quantum-optics enthusiast

    OpenAIRE

    Branczyk, Agata M.; Turner, Daniel B.; Scholes, Gregory D.

    2013-01-01

    Recent interest in the role of quantum mechanics in the primary events of photosynthetic energy transfer has led to a convergence of nonlinear optical spectroscopy and quantum optics on the topic of energy-transfer dynamics in pigment-protein complexes. The convergence of these two communities has unveiled a mismatch between the background and terminology of the respective fields. To make connections, we provide a pedagogical guide to understanding the basics of two-dimensional electronic spe...

  16. An Electron Energy Loss Spectroscopy Study of Metallic Nanoparticles of Gold and Silver

    OpenAIRE

    Eccles, James William Lesile

    2010-01-01

    An Electron Energy Loss Spectroscopy Study of Metallic Nanoparticles of Gold and Silver – A thesis submitted for the degree of PhDThe application of gold and silver nanoparticles to areas such as medical research is based on unique optical properties exhibited by some metals. These properties are a direct consequence of localised excitations occurring at visible frequencies known as Surface Plasmon Resonances (SPRs). The exact frequency of an SPR induced in a nanoparticle can be ‘tuned’ in ...

  17. Hyperfine interactions of 57Fe implanted in solids studied by conversion electron Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    The hyperfine interactions of stable 57Fe nuclei implanted in various matrices were studied using conversion electron Moessbauer spectroscopy. The results obtained for 57Fe implanted in aluminium in d-metals in silicon and germanium are presented. The properties of the implantation produced materials and the lattice location of iron impurities are discussed. The information concerning the volume dependence of the hyperfine interactions and the origin of the electric field gradients in solids were obtained. (author)

  18. Ultrafast geometric manipulation of electron spin and detection of the geometric phase via Faraday rotation spectroscopy

    CERN Document Server

    Li Xue Qian; Cen, L X; Zheng, H Z; Yan, Y J; Li, Xin-Qi; Hu, Cheng-Yong; Cen, Li-Xiang; Zheng, Hou-Zhi; Yan, YiJing

    2002-01-01

    Time-resolved Faraday rotation spectroscopy is currently exploited as a powerful technique to probe spin dynamics in semiconductors. We propose here an all-optical approach to geometrically manipulate electron spin and to detect the geometric phase by this type of extremely sensitive experiment. The global nature of the geometric phase can make the quantum manipulation more stable, which may find interesting application in quantum devices.

  19. Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy

    OpenAIRE

    Guillaume Ducournau; Tahsin Akalin; Robin Bocquet; Emilien Peytavit; Karine Blary; Jean-François Lampin; Arnaud Cuisset; Gael Mouret; Chun Yang; Francis Hindle

    2009-01-01

    A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the...

  20. Cryogenic resonance-electron Moessbauer spectroscopy with a helium-filled proportional counter

    International Nuclear Information System (INIS)

    As studied in our previous works,a proportional counter filled with pure helium gas works well at low temperatures near 4.2 K. The helium-filled proportional counter (HFPC) provides us with method to detect nuclear radiations at low temperatures. A typical application of this counter is resonance-electron Moessbauer spectroscopy (REMS) at low temperatures (<∼30 K). In this article some examples of REMS measurements with HFPC are given. (author)

  1. Scanning electron microscopy and Raman spectroscopy of microorganisms related to biofuels and biopolymer production

    Czech Academy of Sciences Publication Activity Database

    Hrubanová, Kamila; Samek, Ota; Obruča, S.; Hároniková, A.; Krzyžánek, Vladislav

    Göttingen: DGE, 2015, s. 700-701. [Microscopy Conference 2015. Göttingen (DE), 06.09.2015-11.09.2015] R&D Projects: GA ČR(CZ) GA14-20012S; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : SEM * Raman spectroscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  2. Measuring temperature in GaN-based high electron mobility transistors by cathodoluminescence spectroscopy

    International Nuclear Information System (INIS)

    In this paper, we performed a high-resolution measurement of channel temperature rise in GaN-based high electron mobility transistors (HEMTs). Cathodoluminescence spectroscopy in the scanning electron microscope was used to probe the temperature rise with several tens of nanometers spatial resolution and accuracy better than ±8 °C. We also determined the temperature distribution and peak temperature change with the power density in active AlGaN/GaN HEMTs in the source–gate and gate–drain openings. The measured results agree reasonably well with physical 2D electrothermal simulations and Raman thermography. (paper)

  3. Probing flexible conformations in molecular junctions by inelastic electron tunneling spectroscopy

    Directory of Open Access Journals (Sweden)

    Mingsen Deng

    2015-01-01

    Full Text Available The probe of flexible molecular conformation is crucial for the electric application of molecular systems. We have developed a theoretical procedure to analyze the couplings of molecular local vibrations with the electron transportation process, which enables us to evaluate the structural fingerprints of some vibrational modes in the inelastic electron tunneling spectroscopy (IETS. Based on a model molecule of Bis-(4-mercaptophenyl-ether with a flexible center angle, we have revealed and validated a simple mathematical relationship between IETS signals and molecular angles. Our results might open a route to quantitatively measure key geometrical parameters of molecular junctions, which helps to achieve precise control of molecular devices.

  4. Probing flexible conformations in molecular junctions by inelastic electron tunneling spectroscopy

    International Nuclear Information System (INIS)

    The probe of flexible molecular conformation is crucial for the electric application of molecular systems. We have developed a theoretical procedure to analyze the couplings of molecular local vibrations with the electron transportation process, which enables us to evaluate the structural fingerprints of some vibrational modes in the inelastic electron tunneling spectroscopy (IETS). Based on a model molecule of Bis-(4-mercaptophenyl)-ether with a flexible center angle, we have revealed and validated a simple mathematical relationship between IETS signals and molecular angles. Our results might open a route to quantitatively measure key geometrical parameters of molecular junctions, which helps to achieve precise control of molecular devices

  5. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  6. Transformation optics: a time- and frequency-domain analysis of electron-energy loss spectroscopy

    CERN Document Server

    Kraft, Matthias; Pendry, J B

    2016-01-01

    Electron energy loss spectroscopy (EELS) and Cathodoluminescence (CL) play a pivotal role in many of the cutting edge experiments in plasmonics. EELS and CL experiments are usually supported by numerical simulations, which, whilst accurate, may not provide as much physical insight as analytical calculations do. Fully analytical solutions to EELS and CL systems in plasmonics are rare and difficult to obtain. This paper aims to narrow this gap by introducing a new method based on Transformation optics that allows to calculate the quasi-static frequency and time-domain response of plasmonic particles under electron beam excitation.

  7. High resolution electron energy loss spectroscopy of narrow gap III-V semiconductor surfaces and interfaces

    CERN Document Server

    Veal, T D

    2002-01-01

    The electronic properties of n-type narrow gap III-V semiconductor surfaces and interfaces are investigated using high-resolution electron-energy-loss spectroscopy (HREELS). Changing the incident electron energy, alters the wave-vector transfer parallel to the surface, allowing the probing depth to be varied over typical space-charge layer widths (100 - 2000 A). Semi-classical dielectric theory simulations of the HREEL spectra are performed to extract quantitative information from the probing energy-dependence of the surface plasmon and phonon peaks. The plasma frequency used in the simulations is related to the electron concentration and effective mass using the Kane model of the non-parabolic conduction band. Space-charge layer parameters are obtained by comparing calculated smooth charge profiles with the histogram profiles that are used in the simulations. Complementary experimental techniques are employed to correlate the reconstruction, chemical composition and morphology of the surface with the electro...

  8. Damage-free vibrational spectroscopy of biological materials in the electron microscope

    Science.gov (United States)

    Rez, Peter; Aoki, Toshihiro; March, Katia; Gur, Dvir; Krivanek, Ondrej L.; Dellby, Niklas; Lovejoy, Tracy C.; Wolf, Sharon G.; Cohen, Hagai

    2016-03-01

    Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an `aloof' electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies guanine crystals in their native state, resolving their characteristic C-H, N-H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ~10 nm, simultaneously combined with imaging in the electron microscope.

  9. Electronic topological transition in zinc under pressure: An x-ray absorption spectroscopy study

    International Nuclear Information System (INIS)

    Zinc metal has been studied at high pressure using x-ray absorption spectroscopy. In order to investigate the role of the different degrees of hydrostaticity on the occurrence of structural anomalies following the electronic topological transition, two pressure transmitting media have been used. Results show that the electronic topological transition, if it exists, does not induce an anomaly in the local environment of compressed Zn as a function of hydrostatic pressure and any anomaly must be related to a loss of hydrostaticity of the pressure transmitting medium. The near-edge structures of the spectra, sensitive to variations in the electronic density of states above the Fermi level, do not show any evidence of electronic transition whatever pressure transmitting medium is used

  10. Ambient-Pressure X-ray Photoelectron Spectroscopy through Electron Transparent Graphene Membranes

    CERN Document Server

    Kraus, Jurgen; Gunther, Sebastian; Gregoratti, Luca; Amati, Matteo; Kiskinova, Maya; Yulaev, Alexander; Vlassiouk, Ivan; Kolmakov, Andrei

    2014-01-01

    Photoelectron spectroscopy (PES) and microscopy are highly demanded for exploring morphologically complex solid-gas and solid-liquid interfaces under realistic conditions, but the very small electron mean free path inside the dense media imposes serious experimental challenges. Currently, near ambient pressure PES is conducted using sophisticated and expensive electron energy analyzers coupled with differentially pumped electron lenses. An alternative economical approach proposed in this report uses ultrathin graphene membranes to isolate the ambient sample environment from the PES detection system. We demonstrate that the graphene membrane separating windows are both mechanically robust and sufficiently transparent for electrons in a wide energy range to allow PES of liquid and gaseous water. The reported proof-of-principle experiments also open a principal possibility to probe vacuum-incompatible toxic or reactive samples enclosed inside the hermetic environmental cells.

  11. Numerical simulation of Electron Energy Loss Spectroscopy using a Generalized Multipole Technique

    Energy Technology Data Exchange (ETDEWEB)

    Kiewidt, Lars [Foundation Institute of Materials Science (IWT), Department of Production Engineering, University of Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany); Karamehmedović, Mirza, E-mail: mirza@iwt.uni-bremen.de [Foundation Institute of Materials Science (IWT), Department of Production Engineering, University of Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany); Matyssek, Christian [Humboldt Universität zu Berlin, AG Theoretische Optik and Photonik, Newtonstr. 15, 12489 Berlin (Germany); Hergert, Wolfram [Martin Luther University Halle, Institute of Physics, Theory Group, von-Seckendorff-Platz 1, 06120 Halle (Germany); Mädler, Lutz [Foundation Institute of Materials Science (IWT), Department of Production Engineering, University of Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany); Institut für Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany); Wriedt, Thomas [Institut für Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen (Germany)

    2013-10-15

    We numerically simulate low-loss Electron Energy Loss Spectroscopy (EELS) of isolated spheroidal nanoparticles, using an electromagnetic model based on a Generalized Multipole Technique (GMT). The GMT is fast and accurate, and, in principle, flexible regarding nanoparticle shape and the incident electron beam. The implemented method is validated against reference analytical and numerical methods for plane-wave scattering by spherical and spheroidal nanoparticles. Also, simulated electron energy loss (EEL) spectra of spherical and spheroidal nanoparticles are compared to available analytical and numerical solutions. An EEL spectrum is predicted numerically for a prolate spheroidal aluminum nanoparticle. The presented method is the basis for a powerful tool for the computation, analysis and interpretation of EEL spectra of general geometric configurations. - Highlights: • We simulate Electron Energy Loss Spectroscopy using a Generalized Multipole Technique. • We achieve good correspondence with reference methods for spherical nanoparticles. • The presented method is a basis for the computation and interpretation of Electron Energy Loss spectra of general geometric configurations.

  12. Electron Energy-Loss Spectroscopy: Fundamentals and applications in the characterization of minerals

    International Nuclear Information System (INIS)

    The combined use of an energy-loss spectrometer and an analytical electron microscope with fine probe forming capabilities provides a wealth of information about the sample at high spatial resolution. Fundamental principles governing the physics of the interaction between the fast electron and a thin foil sample, to account for the fine structure in the inelastically scattered fast electron distribution (Electron-Energy Loss Spectroscopy, EELS), will be reviewed. General application of EELS is in the area of low atomic number elements (Z < 11) microanalysis, where it significantly complements the more widely used Energy Dispersive X-ray Spectroscopy (EDXS). However, a careful analysis of the low loss plasmon oscillations and the fine structure in the core-loss edges, can provide additional information related to the bonding and electronic structure of the sample. An illustration of this is presented from our study of Cδ diamond residue from the Allende carbonaceous chondrite. Combination of EELS with channeling effects can provide specific site occupation/valence information in crystalline materials. Details of this novel crystallographic method will be outlined and illustrated with an example of the study of chromite spinels. Finally, some pertinent experimental details will be discussed. 7 figs

  13. Development of holmium-163 electron-capture spectroscopy with transition-edge sensors

    CERN Document Server

    Croce, M P; Mocko, V; Kunde, G J; Birnbaum, E R; Bond, E M; Engle, J W; Hoover, A S; Nortier, F M; Pollington, A D; Taylor, W A; Weisse-Bernstein, N R; Wolfsberg, L E; Hays-Wehle, J P; Schmidt, D R; Swetz, D S; Ullom, J N; Barnhart, T E; Nickles, R J

    2015-01-01

    Calorimetric decay energy spectroscopy of electron-capture-decaying isotopes is a promising method to achieve the sensitivity required for electron neutrino mass measurement. The very low total nuclear decay energy (QEC < 3 keV) and short half-life (4570 y) of 163Ho make it attractive for high-precision electron capture spectroscopy (ECS) near the kinematic endpoint, where the neutrino momentum goes to zero. In the ECS approach, an electron-capture-decaying isotope is embedded inside a microcalorimeter designed to capture and measure the energy of all the decay radiation except that of the escaping neutrino. We have developed a complete process for proton-irradiation-based isotope production, isolation, and purification of 163Ho. We have developed transition-edge sensors for this measurement and methods for incorporating 163Ho into high-resolution microcalorimeters, and have measured the electron-capture spectrum of 163Ho. We present our work in these areas and discuss the measured spectrum and its compari...

  14. Numerical simulation of Electron Energy Loss Spectroscopy using a Generalized Multipole Technique

    International Nuclear Information System (INIS)

    We numerically simulate low-loss Electron Energy Loss Spectroscopy (EELS) of isolated spheroidal nanoparticles, using an electromagnetic model based on a Generalized Multipole Technique (GMT). The GMT is fast and accurate, and, in principle, flexible regarding nanoparticle shape and the incident electron beam. The implemented method is validated against reference analytical and numerical methods for plane-wave scattering by spherical and spheroidal nanoparticles. Also, simulated electron energy loss (EEL) spectra of spherical and spheroidal nanoparticles are compared to available analytical and numerical solutions. An EEL spectrum is predicted numerically for a prolate spheroidal aluminum nanoparticle. The presented method is the basis for a powerful tool for the computation, analysis and interpretation of EEL spectra of general geometric configurations. - Highlights: • We simulate Electron Energy Loss Spectroscopy using a Generalized Multipole Technique. • We achieve good correspondence with reference methods for spherical nanoparticles. • The presented method is a basis for the computation and interpretation of Electron Energy Loss spectra of general geometric configurations

  15. Group velocity delay spectroscopy technique for industrial monitoring of electron beam induced vapors

    Energy Technology Data Exchange (ETDEWEB)

    Benterou, J J; Berzins, L V; Sharma, M N

    1998-09-24

    Spectroscopic techniques are ideal for characterization and process control of electron beam generated vapor plumes. Absorption based techniques work well for a wide variety of applications, but are difficult to apply to optically dense or opaque vapor plumes. We describe an approach for monitoring optically dense vapor plumes that is based on measuring the group velocity delay of a laser beam near an optical transition to determine the vapor density. This technique has a larger dynamic range than absorption spectroscopy. We describe our progress towards a robust system to monitor aluminum vaporization in an industrial environment. Aluminum was chosen because of its prevalence in high performance aircraft alloys. In these applications, composition control of the alloy constituents is critical to the deposition process. Data is presented demonstrating the superior dynamic range of the measurement. In addition, preliminary data demonstrating aluminum vapor rate control in an electron beam evaporator is presented. Alternative applications where this technique could be useful are discussed. Keywords: Group velocity delay spectroscopy, optical beat signal, optical heterodyne, index of refraction, laser absorption spectroscopy, external cavity diode laser (ECDL), electron beam vaporization, vapor density, vapor phase manufacturing, process control

  16. Dynamic localization of electronic excitation in photosynthetic complexes revealed with chiral two-dimensional spectroscopy

    Science.gov (United States)

    Fidler, Andrew F.; Singh, Ved P.; Long, Phillip D.; Dahlberg, Peter D.; Engel, Gregory S.

    2014-02-01

    Time-resolved ultrafast optical probes of chiral dynamics provide a new window allowing us to explore how interactions with such structured environments drive electronic dynamics. Incorporating optical activity into time-resolved spectroscopies has proven challenging because of the small signal and large achiral background. Here we demonstrate that two-dimensional electronic spectroscopy can be adapted to detect chiral signals and that these signals reveal how excitations delocalize and contract following excitation. We dynamically probe the evolution of chiral electronic structure in the light-harvesting complex 2 of purple bacteria following photoexcitation by creating a chiral two-dimensional mapping. The dynamics of the chiral two-dimensional signal directly reports on changes in the degree of delocalization of the excitonic states following photoexcitation. The mechanism of energy transfer in this system may enhance transfer probability because of the coherent coupling among chromophores while suppressing fluorescence that arises from populating delocalized states. This generally applicable spectroscopy will provide an incisive tool to probe ultrafast transient molecular fluctuations that are obscured in non-chiral experiments.

  17. Investigation of ageing characteristics and identification of surface chemical changes on SrGa2S4:Ce3+ display phosphor under electron beam bombardment

    International Nuclear Information System (INIS)

    Cathodoluminescent ageing characteristics of SrGa2S4:Ce3+ under prolonged electron beam bombardment was studied and the data are presented. The cathodoluminescent intensity with an increasing Coulomb loading was observed to degrade under different primary electron beam voltages. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to monitor the surface chemical changes during electron beam bombardment and after the degradation process. Auger peak to peak heights monitored during the ageing process suggest a loss in S and C and an initial increase in oxygen concentration on the surface. XPS results indicate the formation of a SrO overlayer due to electron stimulated surface chemical reactions (ESSCRs).

  18. The Pierre Auger Cosmic Ray Observatory

    CERN Document Server

    ,

    2015-01-01

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above $10^{17}$ eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km$^2$, 61 detector infill array. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km$^2$ sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Auger Observatory.

  19. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

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

    Energy Technology Data Exchange (ETDEWEB)

    Monreal, R.C., E-mail: r.c.monreal@uam.es [Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Centre (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Goebl, D.; Primetzhofer, D.; Bauer, P. [Institut für Experimentalphysik, Abteilung für Atom-und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz (Austria)

    2013-11-15

    In this work we compare characteristics of Auger neutralization of He{sup +} 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.