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Sample records for atom bombardment mass

  1. Fast atom bombardment mass spectrometry of condensed tannin sulfonate derivatives

    Science.gov (United States)

    J.J. Karchesy; L.Y. Foo; Richard W. Hemingway; E. Barofsky; D.F. Barofsky

    1989-01-01

    Condensed tannin sulfonate derivatives were studied by fast atom bombardment mass spectrometry (FAB-MS) to assess the feasibility of using this technique for determining molecular weight and structural information about these compounds. Both positive- and negative-ion spectra provided useful data with regard to molecular weight, cation species present, and presence of...

  2. Fast atom bombardment tandem mass spectrometry of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)

    1995-02-01

    Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

  3. Fast atom bombardment mass spectrometric and tandem mass spectrometric studies of some functionalized tetrapyrroles derived from chlorophylls a and b

    Energy Technology Data Exchange (ETDEWEB)

    Keely, B.J.; Maxwell, J.R. (Univ. of Bristol (England))

    Fast atom bombardment (FAB) mass spectra of a number of functionalized tetrapyrroles derived from chlorophylls a and b have been obtained and MS/MS studies used to investigate aspects of the fragmentation behavior of some of them. The application of this approach is demonstrated by the assignment of pheophytin b isolated from a lake sediment where the amount and purity were insufficient for {sup 1}H nuclear magnetic resonance spectroscopic studies.

  4. Structure determination of adipokinetic hormones using fast atom bombardment tandem mass spectrometry; An unknown adipokinetic hormone (AKH-III) from Locusta migratoria

    Energy Technology Data Exchange (ETDEWEB)

    Heerma, W.; Versluis, C.; Lankhof, H. (Utrecht University (Netherlands). Faculty of Chemistry, Department of Analytical Molecular Spectrometry); Oudejans, R.C.H.M.; Kooiman, F.P.; Beenakkers, A.M.T. (Utrecht University (Netherlands). Department of Experimental Zoology)

    1991-08-01

    Fast atom bombardment mass spectrometry combined with various tandem mass spectrometric techniques and accurate mass measurement were used to elucidate the structure of an unknown biologically active peptide isolated from Locusa migratoria. (author). 23 refs.; 6 figs.; 2 schemes.

  5. Metabolism of cycloate in radish leaf: metabolite identification by packed capillary flow fast atom bombardment tandem mass spectrometry.

    Science.gov (United States)

    Onisko, B C; Barnes, J P; Staub, R E; Walker, F H; Kerlinger, N

    1994-10-01

    The metabolism of cycloate, a thiocarbamate herbicide, was investigated in mature radish leaf. Twelve new metabolites were identified by liquid chromatographic/mass spectrometric analysis using fast atom bombardment and packed capillary liquid chromatography columns. Full-scan and tandem mass spectrometric methods were employed. Application of the on-column focusing technique resulted in identifications with injections of as little as 15 ng of metabolite (20 ppb in radish). This injection technique allows the practical use of packed capillary liquid chromatography/mass spectrometry in sample-limited applications. Cycloate is oxidized to several ring-hydroxylated isomers that are subsequently glucosylated and esterified with malonic acid. Cycloate is also conjugated with glutathione. Metabolic hydrolysis of the glutathione conjugate formed a cysteine conjugate that is further metabolized by amidation with either malonic or acetic acid. Transamination of the cysteine conjugate gave a thiolactic acid derivative. Metabolites were also identified that were the result of both ring-hydroxylation and conjugation with glutathione. One of these, an N-acetylcysteine conjugate, is the first report of a mercapturic acid in plants. The structures of two of the new metabolites were confirmed by chemical synthesis.

  6. Fast atom bombardment mass spectral analysis of three new oxidative products of primaquine

    Science.gov (United States)

    Sinha, Sukesh N.; Dua, V. K.

    2004-03-01

    FAB mass spectrum of 5,5-di-[6-methoxy-8-(4'-amino-1'butyl amino)] quinoline (PI) was recorded in three different concentrations to establish the structure of new oxidative products of primaquine and also the effect of matrix on percentage relative abundance of molecular as well as fragment ions which were demonstrated first time. At three concentrations, three different behaviors of matrix, molecular and fragment ions were observed. At higher concentration (>1 nM) molecular ion behaved as a base peak, but due to side reaction with matrix certain extra peak were also obtained. Thus, the higher concentration was interesting to show the side reaction of analyte with m-nitro-benzyl alcohol (NBA) but not for molecular weight determination. At the lowest concentration (cure of relapsing malaria.

  7. Comparison of electron ionization and fast atom bombardment-mass spectrometry for the determination of nickel, vanadyl and free-base porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A.J.; Van Berkel, G.J.; Doolittle, F.G.; Filby, R.H. (Washington State Univ., Pullman (USA))

    1989-01-01

    Fast Atom Bombardment-Mass Spectrometry (FAB-MS) and Electron Ionization-Mass Spectrometry (EI-MS) at 12 and 70 eV, were used to obtain mass spectra of mesoporphyrin IX dimethylester (DME), tetraphenylporphyrin (TPP), octaethylporphyrin (OEP), and the metal-loporphyrins, Ni(DME), Ni(TPP), Ni(OEP), VO(TPP), VO(OEP), as well as a VO(II) porphyrin concentrate obtained from the New Albany oil shale bitumen (Mississippian-Devonian). A mixture of dithiothreitol/dithioerythritol (Magic Bullet) was used as the FAB matrix. Greater fragmentation of free-base and metalloporphyrins was observed in FAB mass spectra compared to the EI mass spectra. Adduct ions formed by addition of sulfur and a matrix molecule to the porphyrins were observed. In FAB spectra of the VO(II) complexes, loss of oxygen was noted. The FAB mass spectra of mixtures of VO(II) geoporphyrins are much more complex than corresponding EI mass spectra because of the greater fragmentation and the multiplicity of ions (M{sup +}, M + H, M + 2H, etc.) observed in the FAB mode. Using the matrices investigated, FAB is less suitable for EI for the mass spectrometric analysis of the geoporphyrins.

  8. Metabolism of 15-(4'-[[sup 123]I]iodophenyl)pentadecanoic acid ([[sup 123]I]IPPA) in the rat heart; identification of new metabolites by high pressure liquid chromatography and fast atom bombardment-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhut, Michael; Suetterle, Andreas (Heidelberg Univ. (Germany). Abt. fuer Klinische Nuklearmedizin); Lehmann, W.D. (Deutsches Krebsforschungszentrum, Heidelberg (Germany))

    1993-08-01

    The metabolism of 15-(4'-iodophenyl)pentadecanoic acid (IPPA) in the heart muscle is commonly believed to end at 4-iodobenzoic acid as the main and final product of [beta]-oxidation. However, investigation of the metabolic fate of IPPA in Langendorff rat hearts using high pressure liquid chromatography (HPLC) and negative fast atom bombardment mass spectrometry (FAB-MS) revealed new results. This metabolic behaviour may be of importance for the interpretation of sequential heart scintigraphy performed with [[sup 123]I]IPPA. (author).

  9. Metabolism of 15-(4'-[123I]iodophenyl)pentadecanoic acid ([123I]IPPA) in the rat heart; identification of new metabolites by high pressure liquid chromatography and fast atom bombardment-mass spectrometry.

    Science.gov (United States)

    Eisenhut, M; Lehmann, W D; Sütterle, A

    1993-08-01

    The metabolism of 15-(4'-iodophenyl)pentadecanoic acid (IPPA) in the heart muscle is commonly believed to end at 4-iodobenzoic acid as the main and final product of beta-oxidation. However, investigation of the metabolic fate of IPPA in Langendorff rat hearts using high pressure liquid chromatography (HPLC) and negative fast atom bombardment mass spectrometry (FAB-MS) revealed new results. After perfusing isolated rat hearts with [123I]IPPA, metabolites were monitored by HPLC using simultaneous detection of gamma-radioactivity and u.v. absorbance. The identification of HPLC separated metabolites was based on their nominal molecular weights as determined by negative FAB-MS. According to these measurements five catabolites were identified with decreasing concentration: 3-(4'-iodophenyl)propanoic acid > 3-(4'-iodophenyl)propanoic acid = 5-(4'-iodophenyl)-3-hydroxypentanoic acid > 4-iodobenzoic acid. Additionally, an anabolic metabolite was found exclusively in the lipid ester fraction. From the hydrolysed heart lipids this compound was identified as 11-(4'-iodophenyl)undecanoic acid. Its formation is explained by the action of cytosolic fatty acid synthetase on IPPA catabolites. This metabolic behaviour may be of importance for the interpretation of sequential heart scintigraphy performed with [123I]IPPA.

  10. Coordination of sodium cation to an oxygen function and olefinic double bond to form molecular adduct ion in fast atom bombardment mass spectrometry.

    Science.gov (United States)

    Morisaki, Naoko; Kobayashi, Hisayoshi; Yamamura, Yumiko; Morisaki, Masuo; Nagasawa, Kazuo; Hashimoto, Yuichi

    2002-07-01

    Steroidal allylic alcohols formed Na+ adduct ion peaks [M+Na]+ by the addition of NaCl in FAB mass spectrometry. A comparison of the intensities of the adduct ion peaks of allylic alcohols with those of the corresponding saturated alcohols and olefin suggested that the olefinic double bond and the proximal hydroxyl group had coordinated to Na+. The adduct ion was stable and did not undergo dehydroxylation. We suggest that the Na+ adduction will be useful for the molecular weight determination of allylic alcohols which are susceptible to dehydroxylation under FAB mass spectrometric conditions. Na+ adduct ions of alpha,beta-unsaturated carbonyl compounds were also investigated.

  11. Modified morphology of graphene sheets by Argon-atom bombardment: molecular dynamics simulations.

    Science.gov (United States)

    Wei, Xiao-Lin; Zhang, Kai-Wang; Wang, Ru-Zhi; Liu, Wen-Liang; Zhong, Jian-Xin

    2011-12-01

    By a molecular dynamics method, we simulated the process of Argon-atom bombardment on a graphene sheet with 2720 carbon atoms. The results show that, the damage of the bombardment on the graphene sheet depends not only on the incident energy but also on the particle flux density of Argon atoms. To compare and analyze the effect of the incident energy and the particle flux density in the Argon-atom bombardment, we defined the impact factor on graphene sheet by calculating the broken-hole area. The results indicate that, there is an exponential accumulated-damage for the impact of both the incident energy and the particle flux density and there is a critical incident energy ranging from 20-30 eV/atom in Argon-atom bombardment. Different configurations, such as sieve-like and circle-like graphene can be formed by controlling of different particle flux density as the incident energy is more than the critical value. Our results supply a feasible method on fabrication of porous graphene-based materials for gas-storages and molecular sieves, and it also helps to understand the damage mechanism of graphene-based electronic devices under high particle radiation.

  12. Theoretical simulations of atomic and polyatomic bombardment of an organic overlayer on a metallic substrate

    CERN Document Server

    Krantzman, K D; Delcorte, A; Garrison, B J

    2003-01-01

    Our previous molecular dynamics simulations on initial test systems have laid the foundation for understanding some of the effects of polyatomic bombardment. In this paper, we describe simulations of the bombardment of a more realistic model system, an overlayer of sec-butyl-terminated polystyrene tetramers on a Ag left brace 1 1 1 right brace substrate. We have used this model system to study the bombardment with Xe and SF sub 5 projectiles at kinetic energies ranging from 0.50 to 5.0 keV. SF sub 5 sputters more molecules than Xe, but a higher percentage of these are damaged rather than ejected intact when the bombarding energy is greater than 0.50 keV. Therefore, at energies comparable to experimental values, the efficiency, measured as the yield-to-damage ratio, is greater with Xe than SF sub 5. Stable and intact molecules are generally produced by upward moving substrate atoms, while fragments are produced by the upward and lateral motion of reflected projectile atoms and fragments from the target molecul...

  13. Characteristics of flows of energetic atoms reflected from metal targets during ion bombardment

    Science.gov (United States)

    Kuzmichev, A.; Perevertaylo, V.; Tsybulsky, L.; Volpian, O.

    2016-07-01

    Particle number and energy reflection coefficients for energetic neutralized gas ions (Ar and O atoms) backscattered from metal targets during ion bombardment have been calculated using TRIM code. The energy distributions of reflected atoms are computed, too, and their dependence on the primary ion energy and the angle of ion incidence is determined. The obtained data confirm the possibility of employing energetic atoms reflection for generation of high energy neutral beams and point out to take this phenomenon into account under analysis of the ion technology for coating deposition.

  14. Investigation of energy thresholds of atomic and cluster sputtering of some elements under ion bombardment

    CERN Document Server

    Atabaev, B G; Lifanova, L F

    2002-01-01

    Threshold energies of sputtering of negative cluster ions from the Si(111) surface were measured at bombardment by Cs sup + , Rb sup + , and Na sup + ions with energy of 0.1-3.0 keV. These results are compared with the calculations of the similar thresholds by Bohdansky etc. formulas (3) for clusters Si sub n sup - and Cu sub n sup - with n=(1-5) and also for B, C, Al, Si, Fe, Cu atoms. Threshold energies of sputtering for the above elements were also estimated using the data from (5). Satisfactory agreement between the experimental and theoretical results was obtained. (author)

  15. Sequencing procyanidin oligomers by fast atom bombardment mass spectrometry

    Science.gov (United States)

    Joseph J. Karchesy; Richard W. Hemingway; L. Yeap Foo; Elisabeth Barofsky; Douglas F. Barofsky

    1986-01-01

    Polymeric procyanidins (condensed tannins) are present in a wide distribution of plants, occurring in particularly high concentrations in some barks, leaves, and fruits (1). These phenolic polymers complex with proteins and therefore inhibit enzyme activity (2), are important contributors to the flavor of foods (3, 4), and influence the nutritional value of plants (5,6...

  16. Selective atomic-level etching using two heating procedures, infrared irradiation and ion bombardment, for next-generation semiconductor device manufacturing

    Science.gov (United States)

    Shinoda, K.; Miyoshi, N.; Kobayashi, H.; Miura, M.; Kurihara, M.; Maeda, K.; Negishi, N.; Sonoda, Y.; Tanaka, M.; Yasui, N.; Izawa, M.; Ishii, Y.; Okuma, K.; Saldana, T.; Manos, J.; Ishikawa, K.; Hori, M.

    2017-05-01

    The demand for precisely controlled etching is increasing as semiconductor device geometries continue to shrink. To fulfill this demand, cyclic atomic level/layer etching will become one of the key technologies in semiconductor device manufacturing at nanometer dimensions. This review describes recent trends in semiconductor devices and some of the latest results on cyclic atomic-level etching. In particular, it focuses on two types of cyclic etching that use different heating procedures: infrared irradiation for isotropic etching and Ar+ ion bombardment for anisotropic etching. It describes how an inductively-coupled-plasma down-flow etching apparatus with infrared lamps can be used for isotropic cyclic etching. The isotropic cyclic etching of SiN involves the formation and thermal desorption of ammonium hexafluorosilicate-based surface modified layers. This method features high selectivity with respect to SiO2, atomic-level control of the amount of SiN etching, and isotropic etched features. On the other hand, the anisotropic cyclic etching with Ar+ ion bombardment uses a microwave electron-cyclotron-resonance plasma etching apparatus. The anisotropic process for poly Si is composed of cyclic repetitions of chlorine adsorption and Ar+ ion bombardment. The anisotropic process for SiN is composed of cyclic repetitions involving an adsorption step using hydrofluorocarbon chemistry and a desorption step using Ar+ ion bombardment. Potential applications of these isotropic/anisotropic cyclic etching processes are described.

  17. Reactive Molecular Simulation of the Damage Mitigation Efficacy of POSS-, Graphene-, and Carbon Nanotube-Loaded Polyimide Coatings Exposed to Atomic Oxygen Bombardment.

    Science.gov (United States)

    Rahmani, Farzin; Nouranian, Sasan; Li, Xiaobing; Al-Ostaz, Ahmed

    2017-04-12

    Reactive molecular dynamics simulation was employed to compare the damage mitigation efficacy of pristine and polyimide (PI)-grafted polyoctahedral silsesquioxane (POSS), graphene (Gr), and carbon nanotubes (CNTs) in a PI matrix exposed to atomic oxygen (AO) bombardment. The concentration of POSS and the orientation of Gr and CNT nanoparticles were further investigated. Overall, the mass loss, erosion yield, surface damage, AO penetration depth, and temperature evolution are lower for the PI systems with randomly oriented CNTs and Gr or PI-grafted POSS compared to those of the pristine POSS or aligned CNT and Gr systems at the same nanoparticle concentration. On the basis of experimental early degradation data (before the onset of nanoparticle damage), the amount of exposed PI, which has the highest erosion yield of all material components, on the material surface is the most important parameter affecting the erosion yield of the hybrid material. Our data indicate that the PI systems with randomly oriented Gr and CNT nanoparticles have the lowest amount of exposed PI on the material surface; therefore, a lower erosion yield is obtained for these systems compared to that of the PI systems with aligned Gr and CNT nanoparticles. However, the PI/grafted-POSS system has a significantly lower erosion yield than that of the PI systems with aligned Gr and CNT nanoparticles, again due to a lower amount of exposed PI on the surface. When comparing the PI systems loaded with PI-grafted POSS versus pristine POSS at low and high nanoparticle concentrations, our data indicate that grafting the POSS and increasing the POSS concentration lower the erosion yield by a factor of about 4 and 1.5, respectively. The former is attributed to a better dispersion of PI-grafted POSS versus that of the pristine POSS in the PI matrix, as determined by the radial distribution function.

  18. CNT welding through Ar bombardment using AIREBO potential and optimization of an extensionded AIREO potential for F atom to simulate hydrofluorocarbons

    Science.gov (United States)

    Kucukkal, Mustafa Umut

    Molecular Dynamics (MD) is an effective method to study diverse systems to gain atomistic level details from the trajectories of particles in the system. MD require a potential which describes the interaction of the particles within the system, which is then used to solve Newton's equation of motion to obtain the trajectories of the particles. For an accurate simulation of a system, an appropriate potential should be used for the MD simulations. The Adaptive Interactive Reactive Empirical Bond Order (AIREBO) potential is a promising potential for MD simulations of systems involving bond breakage or formation [1, 2]. The AIREBO potential is a Tersoff-style bond order potential which adds LJ and torsional interactions to REBO potential developed by Brenner et al [3, 4]. Currently, the AIREBO potential is well parameterized to study carbonaceous and hydrocarbon systems. In the first part of this study, the AIREBO potential is used in MD simulations to study the welding of single wall carbon nanotubes (SWCNTs) through Ar bombardment. SWCNTs have unique electronic properties which make them an appropriate candidate to use in nanoscale transistor and nanocomputer studies. An optimum conductivity through SWCNTs is required for these applications in electronic devices and it is achieved by the bonding arrangements of the carbon atoms in the junction area. This spatial bonding between SWCNTs can be obtained by various experimental methods such as electron beam radiation, fast atom bombardment and chemical vapor deposition. This study focuses on simulating Ar bombardment over cross junction of two SWCNTs placed on an imaginary Lennard-Jones surface perpendicular to each other. The cross junction area of SWCNTs was bombarded with Ar atoms of various kinetic energies in microcanical ensemble which is followed by annealing at various temperatures. The main goal of this study is to find optimum conditions to obtain the highest number of connections between the SWCNTs and the

  19. The 1986-87 atomic mass predictions

    Science.gov (United States)

    Haustein, P. E.

    1987-12-01

    A project to perform a comprehensive update of the atomic mass predictions has recently been concluded and will be published shortly in Atomic Data and Nuclear Data Tables. The project evolved from an ongoing comparison between available mass predictions and reports of newly measured masses of isotopes throughout the mass surface. These comparisons have highlighted a variety of features in current mass models which are responsible for predictions that diverge from masses determined experimentally. The need for a comprehensive update of the atomic mass predictions was therefore apparent and the project was organized and began at the last mass conference (AMCO-VII). Project participants included: Pape and Anthony; Dussel, Caurier and Zuker; Möller and Nix; Möller, Myers, Swiatecki and Treiner; Comay, Kelson, and Zidon; Satpathy and Nayak; Tachibana, Uno, Yamada and Yamada; Spanier and Johansson; Jänecke and Masson; and Wapstra, Audi and Hoekstra. An overview of the new atomic mass predictions may be obtained by written request.

  20. Atomic mass spectrometry of materials

    Science.gov (United States)

    Anthony, J. M.; Matteson, S.; Duggan, J. L.; Elliott, P.; Marble, D.; McDaniel, F. D.; Weathers, D.

    1990-12-01

    Texas Instruments and the University of North Texas (UNT) are collaborating on the design of an accelerator mass spectrometry (AMS) system dedicated primarily to the analysis of impurities in electronic materials and metals. An AMS beamline consisting of high-resolution magnetic ( {M}/{dM } > 350) and electrostatic ( {E}/{dE } > 700) analysis followed by a surface barrier detector has been installed on the NEC 9SDH pelletron at UNT, and a "clean" ion source is under development. An existing ion source (NEC Cs sputter source) has been used in conjunction with the AMS beamline to generate computer controlled molecule-free mass analyses of solid samples. Through a careful choice of isotopes and charge states a robust algorithm can be developed for removing molecular interferences from the mass analysis for essentially all materials. Examples using graphite, Si and CdZnTe are discussed.

  1. Effects of mass defect in atomic clocks

    Science.gov (United States)

    Taichenachev, A. V.; Yudin, V. I.

    2018-01-01

    We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (such as gravitational and quadratic Doppler shifts) can be interpreted as consequences of the mass defect, i.e., without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions..

  2. The 2012 Atomic Mass Evaluation and the Mass Tables

    Energy Technology Data Exchange (ETDEWEB)

    Audi, G., E-mail: amdc.audi@gmail.com [CSNSM, CNRS/IN2P3, Université Paris-Sud, F-91405 Orsay Campus (France); Wang, M. [CSNSM-Orsay, Institute of Modern Physics, Lanzhou 730000 (China); MPI-K, D-69117 Heidelberg (Germany); Wapstra, A.H. [NIKHEF, 1009DB Amsterdam (Netherlands); Kondev, F.G. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); MacCormick, M. [IPN, CNRS/IN2P3, Université Paris-Sud, F-91406 Orsay cedex (France); Xu, X. [IMP, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing, 100049 (China)

    2014-06-15

    The new evaluation of the Atomic Masses, Ame2012, has just been released. It represents a major step in the history of the 60 year old Atomic Mass Evaluation based on the method developed by Wapstra. This new publication includes all material available to date. Some of the policies and procedures used in our evaluation are reported, together with an illustration of one specially difficult case, the energy available for the {sup 102}Pd double-electron capture. The observation of the mass surface reveals many important new features. We illustrate this statement by the double magicity of {sup 270}Hs at N = 162 and Z = 108.

  3. Recent advances in secondary ion mass spectrometry of solid acid catalysts : Large zeolite crystals under bombardment

    NARCIS (Netherlands)

    Hofmann, Jan P.; Rohnke, Marcus; Weckhuysen, Bert M.

    2014-01-01

    This Perspective aims to inform the heterogeneous catalysis and materials science community about the recent advances in Time-of-Flight-Secondary Ion Mass Spectrometry (ToF-SIMS) to characterize catalytic solids by taking large model H-ZSM-5 zeolite crystals as a showcase system. SIMS-based

  4. Analysis of Saxitoxin from Urine Using Continuous-Flow Fast Atom Bombardment & Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    1993-04-30

    plasma or serum are warranted in that PSP may circulate in the blood system for significant periods similar to ochratoxin in human blood . 11 4000, Y...to ingestion of contaminated mussels or in clandestine poisoning as in biological warfare. Additional experiments with the detection of STX in blood

  5. Atomic Mass and Nuclear Binding Energy for Pu-239 (Plutonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Pu-239 (Plutonium, atomic number Z = 94, mass number A = 239).

  6. Atomic Mass and Nuclear Binding Energy for Hs-349 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-349 (Hassium, atomic number Z = 108, mass number A = 349).

  7. Atomic Mass and Nuclear Binding Energy for Hs-298 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-298 (Hassium, atomic number Z = 108, mass number A = 298).

  8. Atomic Mass and Nuclear Binding Energy for Hs-333 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-333 (Hassium, atomic number Z = 108, mass number A = 333).

  9. Atomic Mass and Nuclear Binding Energy for Hs-326 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-326 (Hassium, atomic number Z = 108, mass number A = 326).

  10. Atomic Mass and Nuclear Binding Energy for Hs-313 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-313 (Hassium, atomic number Z = 108, mass number A = 313).

  11. Atomic Mass and Nuclear Binding Energy for Hs-321 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-321 (Hassium, atomic number Z = 108, mass number A = 321).

  12. Atomic Mass and Nuclear Binding Energy for Hs-304 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-304 (Hassium, atomic number Z = 108, mass number A = 304).

  13. Atomic Mass and Nuclear Binding Energy for Hs-311 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-311 (Hassium, atomic number Z = 108, mass number A = 311).

  14. Atomic Mass and Nuclear Binding Energy for Hs-323 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-323 (Hassium, atomic number Z = 108, mass number A = 323).

  15. Atomic Mass and Nuclear Binding Energy for Hs-335 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-335 (Hassium, atomic number Z = 108, mass number A = 335).

  16. Atomic Mass and Nuclear Binding Energy for Hs-322 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-322 (Hassium, atomic number Z = 108, mass number A = 322).

  17. Atomic Mass and Nuclear Binding Energy for Hs-325 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-325 (Hassium, atomic number Z = 108, mass number A = 325).

  18. Atomic Mass and Nuclear Binding Energy for Hs-316 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-316 (Hassium, atomic number Z = 108, mass number A = 316).

  19. Atomic Mass and Nuclear Binding Energy for Hs-355 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-355 (Hassium, atomic number Z = 108, mass number A = 355).

  20. Atomic Mass and Nuclear Binding Energy for Hs-336 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-336 (Hassium, atomic number Z = 108, mass number A = 336).

  1. Atomic Mass and Nuclear Binding Energy for Hs-286 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-286 (Hassium, atomic number Z = 108, mass number A = 286).

  2. Atomic Mass and Nuclear Binding Energy for Hs-305 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-305 (Hassium, atomic number Z = 108, mass number A = 305).

  3. Atomic Mass and Nuclear Binding Energy for Hs-283 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-283 (Hassium, atomic number Z = 108, mass number A = 283).

  4. Atomic Mass and Nuclear Binding Energy for Hs-334 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-334 (Hassium, atomic number Z = 108, mass number A = 334).

  5. Atomic Mass and Nuclear Binding Energy for Hs-302 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-302 (Hassium, atomic number Z = 108, mass number A = 302).

  6. Atomic Mass and Nuclear Binding Energy for Hs-280 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-280 (Hassium, atomic number Z = 108, mass number A = 280).

  7. Atomic Mass and Nuclear Binding Energy for Hs-341 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-341 (Hassium, atomic number Z = 108, mass number A = 341).

  8. Atomic Mass and Nuclear Binding Energy for Hs-351 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-351 (Hassium, atomic number Z = 108, mass number A = 351).

  9. Atomic Mass and Nuclear Binding Energy for Hs-344 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-344 (Hassium, atomic number Z = 108, mass number A = 344).

  10. Atomic Mass and Nuclear Binding Energy for Hs-319 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-319 (Hassium, atomic number Z = 108, mass number A = 319).

  11. Atomic Mass and Nuclear Binding Energy for Hs-342 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-342 (Hassium, atomic number Z = 108, mass number A = 342).

  12. Atomic Mass and Nuclear Binding Energy for Hs-345 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-345 (Hassium, atomic number Z = 108, mass number A = 345).

  13. Atomic Mass and Nuclear Binding Energy for Hs-306 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-306 (Hassium, atomic number Z = 108, mass number A = 306).

  14. Atomic Mass and Nuclear Binding Energy for Hs-301 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-301 (Hassium, atomic number Z = 108, mass number A = 301).

  15. Atomic Mass and Nuclear Binding Energy for Hs-289 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-289 (Hassium, atomic number Z = 108, mass number A = 289).

  16. Atomic Mass and Nuclear Binding Energy for Hs-348 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-348 (Hassium, atomic number Z = 108, mass number A = 348).

  17. Atomic Mass and Nuclear Binding Energy for Hs-290 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-290 (Hassium, atomic number Z = 108, mass number A = 290).

  18. Atomic Mass and Nuclear Binding Energy for Hs-299 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-299 (Hassium, atomic number Z = 108, mass number A = 299).

  19. Atomic Mass and Nuclear Binding Energy for Hs-356 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-356 (Hassium, atomic number Z = 108, mass number A = 356).

  20. Atomic Mass and Nuclear Binding Energy for Hs-307 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-307 (Hassium, atomic number Z = 108, mass number A = 307).

  1. Atomic Mass and Nuclear Binding Energy for Hs-292 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-292 (Hassium, atomic number Z = 108, mass number A = 292).

  2. Atomic Mass and Nuclear Binding Energy for Hs-340 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-340 (Hassium, atomic number Z = 108, mass number A = 340).

  3. Atomic Mass and Nuclear Binding Energy for Hs-293 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-293 (Hassium, atomic number Z = 108, mass number A = 293).

  4. Atomic Mass and Nuclear Binding Energy for Hs-288 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-288 (Hassium, atomic number Z = 108, mass number A = 288).

  5. Atomic Mass and Nuclear Binding Energy for Hs-317 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-317 (Hassium, atomic number Z = 108, mass number A = 317).

  6. Atomic Mass and Nuclear Binding Energy for Hs-318 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-318 (Hassium, atomic number Z = 108, mass number A = 318).

  7. Atomic Mass and Nuclear Binding Energy for Hs-353 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-353 (Hassium, atomic number Z = 108, mass number A = 353).

  8. Atomic Mass and Nuclear Binding Energy for Hs-354 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-354 (Hassium, atomic number Z = 108, mass number A = 354).

  9. Atomic Mass and Nuclear Binding Energy for Hs-278 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-278 (Hassium, atomic number Z = 108, mass number A = 278).

  10. Atomic Mass and Nuclear Binding Energy for Hs-343 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-343 (Hassium, atomic number Z = 108, mass number A = 343).

  11. Atomic Mass and Nuclear Binding Energy for Hs-310 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-310 (Hassium, atomic number Z = 108, mass number A = 310).

  12. Atomic Mass and Nuclear Binding Energy for Hs-296 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-296 (Hassium, atomic number Z = 108, mass number A = 296).

  13. Atomic Mass and Nuclear Binding Energy for Hs-324 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-324 (Hassium, atomic number Z = 108, mass number A = 324).

  14. Atomic Mass and Nuclear Binding Energy for Hs-330 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-330 (Hassium, atomic number Z = 108, mass number A = 330).

  15. Atomic Mass and Nuclear Binding Energy for Hs-295 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-295 (Hassium, atomic number Z = 108, mass number A = 295).

  16. Atomic Mass and Nuclear Binding Energy for Hs-309 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-309 (Hassium, atomic number Z = 108, mass number A = 309).

  17. Atomic Mass and Nuclear Binding Energy for Hs-359 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-359 (Hassium, atomic number Z = 108, mass number A = 359).

  18. Atomic Mass and Nuclear Binding Energy for Hs-294 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-294 (Hassium, atomic number Z = 108, mass number A = 294).

  19. Atomic Mass and Nuclear Binding Energy for Hs-300 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-300 (Hassium, atomic number Z = 108, mass number A = 300).

  20. Atomic Mass and Nuclear Binding Energy for Hs-328 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-328 (Hassium, atomic number Z = 108, mass number A = 328).

  1. Atomic Mass and Nuclear Binding Energy for Hs-346 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-346 (Hassium, atomic number Z = 108, mass number A = 346).

  2. Atomic Mass and Nuclear Binding Energy for Hs-284 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-284 (Hassium, atomic number Z = 108, mass number A = 284).

  3. Atomic Mass and Nuclear Binding Energy for Hs-361 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-361 (Hassium, atomic number Z = 108, mass number A = 361).

  4. Atomic Mass and Nuclear Binding Energy for Hs-315 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-315 (Hassium, atomic number Z = 108, mass number A = 315).

  5. Atomic Mass and Nuclear Binding Energy for Hs-352 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-352 (Hassium, atomic number Z = 108, mass number A = 352).

  6. Atomic Mass and Nuclear Binding Energy for Hs-287 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-287 (Hassium, atomic number Z = 108, mass number A = 287).

  7. Atomic Mass and Nuclear Binding Energy for Hs-357 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-357 (Hassium, atomic number Z = 108, mass number A = 357).

  8. Atomic Mass and Nuclear Binding Energy for Hs-337 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-337 (Hassium, atomic number Z = 108, mass number A = 337).

  9. Atomic Mass and Nuclear Binding Energy for Hs-360 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-360 (Hassium, atomic number Z = 108, mass number A = 360).

  10. Atomic Mass and Nuclear Binding Energy for Hs-358 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-358 (Hassium, atomic number Z = 108, mass number A = 358).

  11. Atomic Mass and Nuclear Binding Energy for Hs-331 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-331 (Hassium, atomic number Z = 108, mass number A = 331).

  12. Atomic Mass and Nuclear Binding Energy for Hs-339 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-339 (Hassium, atomic number Z = 108, mass number A = 339).

  13. Atomic Mass and Nuclear Binding Energy for Hs-312 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-312 (Hassium, atomic number Z = 108, mass number A = 312).

  14. Atomic Mass and Nuclear Binding Energy for Hs-282 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-282 (Hassium, atomic number Z = 108, mass number A = 282).

  15. Atomic Mass and Nuclear Binding Energy for Hs-291 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-291 (Hassium, atomic number Z = 108, mass number A = 291).

  16. Atomic Mass and Nuclear Binding Energy for Hs-285 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-285 (Hassium, atomic number Z = 108, mass number A = 285).

  17. Atomic Mass and Nuclear Binding Energy for Hs-332 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-332 (Hassium, atomic number Z = 108, mass number A = 332).

  18. Atomic Mass and Nuclear Binding Energy for Hs-338 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-338 (Hassium, atomic number Z = 108, mass number A = 338).

  19. Atomic Mass and Nuclear Binding Energy for Hs-279 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-279 (Hassium, atomic number Z = 108, mass number A = 279).

  20. Atomic Mass and Nuclear Binding Energy for Hs-281 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-281 (Hassium, atomic number Z = 108, mass number A = 281).

  1. Atomic Mass and Nuclear Binding Energy for Hs-320 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-320 (Hassium, atomic number Z = 108, mass number A = 320).

  2. Atomic Mass and Nuclear Binding Energy for Hs-303 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-303 (Hassium, atomic number Z = 108, mass number A = 303).

  3. Atomic Mass and Nuclear Binding Energy for Hs-297 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-297 (Hassium, atomic number Z = 108, mass number A = 297).

  4. Atomic Mass and Nuclear Binding Energy for Hs-327 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-327 (Hassium, atomic number Z = 108, mass number A = 327).

  5. Atomic Mass and Nuclear Binding Energy for Hs-347 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-347 (Hassium, atomic number Z = 108, mass number A = 347).

  6. Atomic Mass and Nuclear Binding Energy for Hs-308 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-308 (Hassium, atomic number Z = 108, mass number A = 308).

  7. Atomic Mass and Nuclear Binding Energy for Hs-329 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-329 (Hassium, atomic number Z = 108, mass number A = 329).

  8. Atomic Mass and Nuclear Binding Energy for Hs-314 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-314 (Hassium, atomic number Z = 108, mass number A = 314).

  9. Atomic Mass and Nuclear Binding Energy for Hs-350 (Hassium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Hs-350 (Hassium, atomic number Z = 108, mass number A = 350).

  10. On the atomic masses (weights? Of the elements

    Directory of Open Access Journals (Sweden)

    Kaptay G.

    2012-01-01

    Full Text Available Atomic masses (weights? is an essential information for mining and metallurgy. The paper discusses four subjects around this problem. First, the classification of all the elements is suggested into 4 classes, based on their isotope features, determining the accuracy of their known atomic masses. As part of that, the class of elements is discussed with uncertain atomic weights in accordance with the 2009 IUPAC recommendations. A better (easier to use format of atomic weights is presented for this class of elements. Third, it is found not informative to leave empty spaces instead of approximate atomic weights for elements with unstable isotopes. Fourth, the term atomic weight vs the term atomic mass is discussed shortly, in agreement with the SI system of units and in contrary to the questionable IUPAC convection.

  11. Measurement of atomic number and mass attenuation coefficient in ...

    Indian Academy of Sciences (India)

    The linear attenuation coefficient (), mass attenuation coefficient (/ρ), total atomic cross-section (tot), total electronic cross-section (ele) and the effective atomic number (eff) were calculated for pure magnesium ferrite (MgFe2O4). The values of -ray mass attenuation coefficient were obtained using a NaI energy ...

  12. Studying liposomes by tritium bombardment.

    Science.gov (United States)

    Kordyukova, L V; Ksenofontov, A L; Badun, G A; Baratova, L A; Shishkov, A V

    2001-12-01

    Bilayer liposomes from a mixture of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine (DPPC: DPPE = 8:2, molar ratio) or DPPC labeled with 14C-DPPC (DPPC: 14C-DPPC) were bombarded with thermally activated tritium atoms. The tritiated liposomes were hydrolyzed by phospholipase C, and the tritium incorporation into different parts of the bilayer along its thickness was determined. The tritium flux attenuation coefficients were calculated for the headgroup (k1 = 0.176+/-0.032 A(-1)) and acylglycerol residue (k2 = 0.046+/-0.004 A(-1)) layers indicating a preferential attenuation of the tritium flux in the headgroup region and relative transparence of the membrane hydrophobic part. The finding is potentially important to apply tritium bombardment for investigation of spatial organization of transmembrane proteins in their native lipid environment.

  13. Equilibrium vortex lattices of a binary rotating atomic Bose–Einstein condensate with unequal atomic masses

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Biao; Wang, Lin-Xue; Chen, Guang-Ping [Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Chinese Academy of Sciences, Xi’an 710600 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Han, Wei; Zhang, Shou-Gang [Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Chinese Academy of Sciences, Xi’an 710600 (China); Zhang, Xiao-Fei, E-mail: xfzhang@ntsc.ac.cn [Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Chinese Academy of Sciences, Xi’an 710600 (China)

    2016-10-15

    We perform a detailed numerical study of the equilibrium ground-state structures of a binary rotating Bose–Einstein condensate with unequal atomic masses. Our results show that the ground-state distribution and its related vortex configurations are complex events that differ markedly depending strongly on the strength of rotation frequency, as well as on the ratio of atomic masses. We also discuss the structures and radii of the clouds, the number and the size of the core region of the vortices, as a function of the rotation frequency, and of the ratio of atomic masses, and the analytical results agree well with our numerical simulations. This work may open an alternate way in the quantum control of the binary rotating quantum gases with unequal atomic masses. - Highlights: • A binary quantum gases with unequal atomic masses is considered. • Effects of the ratio of atomic masses and rotation frequency are discussed in full parameter space. • The detailed information about both the cloud and vortices are also discussed.

  14. Toward the Atomic-Level Mass Analysis of Biomolecules by the Scanning Atom Probe.

    Science.gov (United States)

    Nishikawa, Osamu; Taniguchi, Masahiro

    2017-04-01

    In 1994, a new type of atom probe instrument, named the scanning atom probe (SAP), was proposed. The unique feature of the SAP is the introduction of a small extraction electrode, which scans over a specimen surface and confines the high field, required for field evaporation of surface atoms in a small space, between the specimen and the electrode. Thus, the SAP does not require a sharp specimen tip. This indicates that the SAP can mass analyze the specimens which are difficult to form in a sharp tip, such as organic materials and biomolecules. Clean single wall carbon nanotubes (CNT), made by high-pressure carbon monoxide process are found to be the best substrates for biomolecules. Various amino acids and dipeptide biomolecules were successfully mass analyzed, revealing characteristic clusters formed by strongly bound atoms in the specimens. The mass analysis indicates that SAP analysis of biomolecules is not only qualitative, but also quantitative.

  15. 4th International Conference on Exotic Nuclei and Atomic Masses

    CERN Document Server

    Gross, Carl J; Rykaczewski, Krzysztof P; The European Physical Journal A : Volume 25, Supplement 1, 2005

    2005-01-01

    The International Conference on Exotic Nuclei and Atomic Masses (ENAM) has gained the status of the premier meeting for the physics of nuclei far from stability. The selected and refereed papers presenting the main results constitute valuable proceedings that offer everyone working in this field an authoritative and comprehensive source of reference.

  16. Analysis of tumour-localizing haematoporphyrin derivative by high-performance liquid chromatography and fast-atom bombardment mass spectrometry

    NARCIS (Netherlands)

    Meijers, J. C.; Lim, C. K.; Lawson, A. M.; Peters, T. J.

    1986-01-01

    Reversed-phase chromatography using a MOS-Hypersil (C8) column with methanol-1 M ammonium acetate buffer (pH 4.6) (60:40) as mobile phase has been developed for the isolation of tumour-localizing haematoporphyrin derivative (HPD). The system effectively resolved the diastereoisomers of

  17. Atomic Oxygen (ATOX) simulation of Teflon FEP and Kapton H surfaces using a high intensity, low energy, mass selected, ion beam facility

    Science.gov (United States)

    Vered, R.; Grossman, E.; Lempert, G. D.; Lifshitz, Y.

    1994-01-01

    A high intensity (greater than 10(exp 15) ions/sq cm) low energy (down to 5 eV) mass selected ion beam (MSIB) facility was used to study the effects of ATOX on two polymers commonly used for space applications (Kapton H and Teflon FEP). The polymers were exposed to O(+) and Ne(+) fluences on 10(exp 15) - 10(exp 19) ions/sq cm, using 30eV ions. A variety of analytical methods were used to analyze the eroded surfaces including: (1) atomic force microscopy (AFM) for morphology measurements; (2) total mass loss measurements using a microbalance; (3) surface chemical composition using x-ray photoelectron spectroscopy (XPS), and (4) residual gas analysis (RGA) of the released gases during bombardment. The relative significance of the collisional and chemical degradation processes was evaluated by comparing the effects of Ne(+) and O(+) bombardment. For 30 eV ions it was found that the Kapton is eroded via chemical mechanisms while Teflon FEP is eroded via collisional mechanisms. AFM analysis was found very powerful in revealing the evolution of the damage from its initial atomic scale (roughness of approx. 1 nm) to its final microscopic scale (roughness greater than 1 micron). Both the surface morphology and the average roughness of the bombarded surfaces (averaged over 1 micron x 1 micron images by the system's computer) were determined for each sample. For 30 eV a non linear increase of the Kapton roughness with the O(+) fluence was discovered (a slow increase rate for fluences phi less than 5 x 10(exp 17) O(+)/sq cm, and a rapid increase rate for phi greater than 5 x 10(exp 17) O(+)/sq cm). Comparative studies on the same materials exposed to RF and DC oxygen plasmas indicate that the specific details of the erosion depend on the simulation facility emphasizing the advantages of the ion beam facility.

  18. On-Line Mass Separator of Superheavy Atoms

    CERN Document Server

    Oganessian, Yu T

    2002-01-01

    The concept is presented of an on-line Mass Analyzer of SuperHeavy Atoms (MASHA) dedicated to the separation and determination of the mass and decay properties of new elements and isotopes produced in heavy-ion induced reactions. The new nuclides with half-lives T_{1/2}\\ge 1 s are transported to an ECR-source working at a frequency of 2.45 GHz and are separated by mass with a mass resolution of M/\\Delta M\\sim 1500. In the focal plane of the magnetic analyzer a front strip detector surrounded by side detectors will be placed to determine the mass according to the signals from the detected alpha-particles or fission fragments with efficiency of about 90 %. In comparison to other existing in-flight recoil separators, the present setup will be characterized by higher efficiency and high selectivity relative to background reaction products. The setup MASHA may be used also in the investigation of nuclear reactions of different type induced by stable and radioactive beams.

  19. Photon mass attenuation coefficients, effective atomic numbers and ...

    Indian Academy of Sciences (India)

    (3) where fi = (ni/ ∑j nj) and Zi are the fractional abundance and atomic number respectively of the constituent element. Here, ni is the total number of atoms of the constituent element and ∑j nj are the total number of atoms of all types present in the compound as per its chemical formula. The effective atomic number, Zeff,.

  20. Direct and Recoil-Induced Electron Emission from Ion-Bombarded Solids

    DEFF Research Database (Denmark)

    Holmen, G.; Svensson, B.; Schou, Jørgen

    1979-01-01

    The kinetic emission of secondary electrons from ion-bombarded solid surfaces is split into two contributions, a direct one caused by ionizing collisions between the bombarding ion and target atoms, and an indirect one originating from ionizing collisions undergone by recoil atoms with other target...... atoms. The direct contribution, which has been treated by several authors in previous studies, shows a behavior that is determined primarily by the electronic stopping power of the bombarding ion, while the indirect contribution is nonproportionally related to the nuclear stopping power. This latter...... contribution is known to be quite important for heavy-ion bombardment at keV energies, and is shown to be of crucial importance for the understanding of the energy dependence of the electron yield in such cases. The model is shown to give consistent results for copper bombarded with electrons, protons...

  1. Effects of metal nanoparticles on the secondary ion yields of a model alkane molecule upon atomic and polyatomic projectiles in secondary ion mass spectrometry.

    Science.gov (United States)

    Wehbe, Nimer; Heile, Andreas; Arlinghaus, Heinrich F; Bertrand, Patrick; Delcorte, Arnaud

    2008-08-15

    A model alkane molecule, triacontane, is used to assess the effects of condensed gold and silver nanoparticles on the molecular ion yields upon atomic (Ga(+) and In(+)) and polyatomic (C60(+) and Bi3(+)) ion bombardment in metal-assisted secondary ion mass spectrometry (MetA-SIMS). Molecular films spin-coated on silicon were metallized using a sputter-coater system, in order to deposit controlled quantities of gold and silver on the surface (from 0 to 15 nm equivalent thickness). The effects of gold and silver islets condensed on triacontane are also compared to the situation of thin triacontane overlayers on metallic substrates (gold and silver). The results focus primarily on the measured yields of quasi-molecular ions, such as (M - H)(+) and (2M - 2H)(+), and metal-cationized molecules, such as (M + Au)(+) and (M + Ag)(+), as a function of the quantity of metal on the surface. They confirm the absence of a simple rule to explain the secondary ion yield improvement in MetA-SIMS. The behavior is strongly dependent on the specific projectile/metal couple used for the experiment. Under atomic bombardment (Ga(+), In(+)), the characteristic ion yields an increase with the gold dose up to approximately 6 nm equivalent thickness. The yield enhancement factor between gold-metallized and pristine samples can be as large as approximately 70 (for (M - H)(+) under Ga(+) bombardment; 10 nm of Au). In contrast, with cluster projectiles such as Bi3(+) and C60(+), the presence of gold and silver leads to a dramatic molecular ion yield decrease. Cluster projectiles prove to be beneficial for triacontane overlayers spin-coated on silicon or metal substrates (Au, Ag) but not in the situation of MetA-SIMS. The fundamental difference of behavior between atomic and cluster primary ions is tentatively explained by arguments involving the different energy deposition mechanisms of these projectiles. Our results also show that Au and Ag nanoparticles do not induce the same behavior in Met

  2. Comment on "Atomic mass compilation 2012" by B. Pfeiffer, K. Venkataramaniah, U. Czok, C. Scheidenberger

    Science.gov (United States)

    Audi, G.; Blaum, K.; Block, M.; Bollen, G.; Goriely, S.; Hardy, J. C.; Herfurth, F.; Kondev, F. G.; Kluge, H.-J.; Lunney, D.; Pearson, J. M.; Savard, G.; Sharma, K. S.; Wang, M.; Zhang, Y. H.

    2015-05-01

    In order to avoid errors and confusion that may arise from the recent publication of a paper entitled "Atomic Mass Compilation 2012", we explain the important difference between a compilation and an evaluation; the former is a necessary but insufficient condition for the latter. The simple list of averaged mass values offered by the "Atomic Mass Compilation" uses none of the numerous links and correlations present in the large body of input data that are carefully maintained within the "Atomic Mass Evaluation". As such, the mere compilation can only produce results of inferior accuracy. Illustrative examples are given.

  3. Highly sensitive solids mass spectrometer uses inert-gas ion source

    Science.gov (United States)

    1966-01-01

    Mass spectrometer provides a recorded analysis of solid material surfaces and bulk. A beam of high-energy inert-gas ions bombards the surface atoms of a sample and converts a percentage into an ionized vapor. The mass spectrum analyzer separates the vapor ionic constituents by mass-to-charge ratio.

  4. Photon mass attenuation coefficients, effective atomic numbers and ...

    Indian Academy of Sciences (India)

    The best-fit coefficients so obtained in the photon energy range of 279.2 to 320.07 keV, 514.0 to 661.6 keV and 1115.5 to 1332.5 keV by a piece-wise interpolation method were then used to find the effective atomic number and electron density of the compounds. These values are found to be in agreement with other ...

  5. Actinide production from xenon bombardments of curium-248

    Energy Technology Data Exchange (ETDEWEB)

    Welch, R.B.

    1985-01-01

    Production cross sections for many actinide nuclides formed in the reaction of /sup 129/Xe and /sup 132/Xe with /sup 248/Cm at bombarding energies slightly above the coulomb barrier were determined using radiochemical techniques to isolate these products. These results are compared with cross sections from a /sup 136/Xe + /sup 248/Cm reaction at a similar energy. When compared to the reaction with /sup 136/Xe, the maxima in the production cross section distributions from the more neutron deficient projectiles are shifted to smaller mass numbers, and the total cross section increases for the production of elements with atomic numbers greater than that of the target, and decreases for lighter elements. These results can be explained by use of a potential energy surface (PES) which illustrates the effect of the available energy on the transfer of nucleons and describes the evolution of the di-nuclear complex, an essential feature of deep-inelastic reactions (DIR), during the interaction. The other principal reaction mechanism is the quasi-elastic transfer (QE). Analysis of data from a similar set of reactions, /sup 129/Xe, /sup 132/Xe, and /sup 136/Xe with /sup 197/Au, aids in explaining the features of the Xe + Cm product distributions, which are additionally affected by the depletion of actinide product yields due to deexcitation by fission. The PES is shown to be a useful tool to predict the general features of product distributions from heavy ion reactions.

  6. Ion bombardment in RF photoguns

    Energy Technology Data Exchange (ETDEWEB)

    Pozdeyev,E.; Kayran, D.; Litvinenko, V. N.

    2009-05-04

    A linac-ring eRHIC design requires a high-intensity CW source of polarized electrons. An SRF gun is viable option that can deliver the required beam. Numerical simulations presented elsewhere have shown that ion bombardment can occur in an RF gun, possibly limiting lifetime of a NEA GaAs cathode. In this paper, we analytically solve the equations of motion of ions in an RF gun using the ponderomotive potential of the Rf field. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper discusses possible mitigation techniques that can reduce the rate of ion bombardment.

  7. The Scales of Time, Length, Mass, Energy, and Other Fundamental Physical Quantities in the Atomic World and the Use of Atomic Units in Quantum Mechanical Calculations

    Science.gov (United States)

    Teo, Boon K.; Li, Wai-Kee

    2011-01-01

    This article is divided into two parts. In the first part, the atomic unit (au) system is introduced and the scales of time, space (length), and speed, as well as those of mass and energy, in the atomic world are discussed. In the second part, the utility of atomic units in quantum mechanical and spectroscopic calculations is illustrated with…

  8. Determination of the Relative Atomic Masses of Metals by Liberation of Molecular Hydrogen

    Science.gov (United States)

    Waghorne, W. Earle; Rous, Andrew J.

    2009-01-01

    Students determine the relative atomic masses of calcium, magnesium, and aluminum by reaction with hydrochloric acid and measurement of the volume of hydrogen gas liberated. The experiment demonstrates stoichiometry and illustrates clearly that mass of the reagent is not the determinant of the amounts in chemical reactions. The experiment is…

  9. Mass screening for prostatic cancer in atomic bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Hideki; Minami, Yuzo; Matsuya, Fukuzo; Yamashita, Syuji; Yushita, Yoshiaki; Sakuragi, Tsutomu; Kanetake, Hiroshi; Saito, Yutaka (Nagasaki Univ. (Japan). School of Medicine)

    1990-03-01

    Men exposed to the atomic bomb were screened for prostatic cancer in Nagasaki City, Japan. From 1983 to 1988, 2,421 subjects were examined. Of the 2,421 men, 12 (0.5%) prostatic cancer patients and 268 (11.1%) patients with benign prostatic hypertrophy requiring treatment were detected. Of the 12 prostatic cancer patients (stage B: 8, stage C: 3, and stage D: 1), 8 (67%) were suffering from early stage cancer. The measurement of serum acid phosphatase was not useful as a screening test for early stage prostatic cancer, since no patient with stage B disease had elevated acid phosphatase activity. The results of our study suggest that the following examination system would be useful for detecting early stage prostatic cancer; a digital rectal examination performed as an initial screening examination and when subjects are judged as needing further examinations, a second screening examination including digital palpation of the prostate, transrectal ultrasonography and an aspiration biopsy for cytological evaluation. (author).

  10. Testing sub-gravitational forces on atoms from a miniature, in-vacuum source mass

    Science.gov (United States)

    Jaffe, Matthew; Haslinger, Philipp; Xu, Victoria; Hamilton, Paul; Upadhye, Amol; Elder, Benjamin; Khoury, Justin; Mueller, Holger

    2017-04-01

    In this talk, I will discuss our recent measurement of the gravitational attraction between cesium atoms in free fall and a centimeter-sized source mass using atom interferometry. Placing the source mass in vacuum provides sensitivity to a wide class of ``fifth force'' type interactions whose effects would otherwise be suppressed beyond detectability in regions of high matter density. Examples include so-called chameleon and symmetron fields, proposed as dark energy candidates. Our measurement tightens constraints on such theories by over two orders of magnitude.

  11. The Atomic Mass Unit, the Avogadro Constant, and the Mole: A Way to Understanding

    Science.gov (United States)

    Baranski, Andrzej

    2012-01-01

    Numerous articles have been published that address problems encountered in teaching basic concepts of chemistry such as the atomic mass unit, Avogadro's number, and the mole. The origin of these problems is found in the concept definitions. If these definitions are adjusted for teaching purposes, understanding could be improved. In the present…

  12. Ultra-precise single-ion atomic mass measurements on deuterium and helium-3

    Science.gov (United States)

    Zafonte, S. L.; Van Dyck, R. S., Jr.

    2015-04-01

    The former University of Washington Penning Trap Mass Spectrometer (UW-PTMS), now located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, was used in the decade before the move to determine new values for the deuteron atomic mass, M (2H+) = 2.013 553 212 745(40) u, and the deuterium atomic mass, M (2H) = 2.014 101 778 052(40) u, both of which are now more than an order-of-magnitude more accurate than the previous best 1994-MIT measurements of these quantities. The new value for the deuteron’s mass can then be used with the accepted 2010-CODATA proton mass and the most recent 1999-measurement of the 2.2 MeV gamma-ray binding energy of the deuteron to refine the neutron’s mass to mn = 1.008 664 916 018(435) u which has about half the uncertainty relative to the value computed using that previous 1994-MIT deuterium measurement. As a result, further improvements of mn must now come from a more accurate determination of the wavelength of this gamma ray. In this same period of time, this spectrometer has also been used to determine new values for the helion atomic mass, M (3He2+) = 3.014 932 246 668(43) u, and the neutral helium-3 atomic mass, M (3He) = 3.016 029 321 675(43) u, which are both about 60 times more accurate than the 2006-SMILETRAP measurements, but disagree with the 4.4-times less-accurate 2015-Florida-State measurements by 0.76 nu. It is expected that these helium-3 results will be used in the future 3H/3He mass ratio (to be determined by the Heidelberg, Germany version of the old UW-PTMS) in order to generate a more accurate value for the tritium atomic mass.

  13. Gas chromatography of organic microcontaminants using atomic emission and mass spectrometric detection combined in one instrument (GC-AED/MS)

    NARCIS (Netherlands)

    Mol, H.G.J.; Hankemeier, T.; Brinkman, U.A.T.

    1999-01-01

    This study describes the coupling of an atomic-emission detector and mass-spectrometric detector to a single gas chromatograph. Splitting of the column effluent enables simultaneous detection by atomic-emission detection (AED) and mass spectrometry (MS) and yields a powerful system for the target

  14. Testing sub-gravitational forces on atoms from a miniature in-vacuum source mass

    Science.gov (United States)

    Jaffe, Matt; Haslinger, Philipp; Xu, Victoria; Hamilton, Paul; Upadhye, Amol; Elder, Benjamin; Khoury, Justin; Müller, Holger

    2017-10-01

    Traditional gravity measurements use bulk masses to both source and probe gravitational fields. Matter-wave interferometers enable the use of probe masses as small as neutrons, atoms and molecular clusters, but still require fields generated by masses ranging from hundreds of kilograms to the entire Earth. Shrinking the sources would enable versatile configurations, improve positioning accuracy, enable tests for beyond-standard-model (`fifth') forces, and allow observation of non-classical effects of gravity. Here we detect the gravitational force between freely falling caesium atoms and an in-vacuum, miniature (centimetre-sized, 0.19 kg) source mass using atom interferometry. Sensitivity down to gravitational strength forces accesses the natural scale for a wide class of cosmologically motivated scalar field models of modified gravity and dark energy. We improve the limits on two such models, chameleons and symmetrons, by over two orders of magnitude. We expect further tests of dark energy theories, and measurements of Newton's gravitational constant and the gravitational Aharonov-Bohm effect.

  15. Time-of-flight mass spectrographs—From ions to neutral atoms

    Science.gov (United States)

    Möbius, E.; Galvin, A. B.; Kistler, L. M.; Kucharek, H.; Popecki, M. A.

    2016-12-01

    After their introduction to space physics in the mid 1980s time-of-flight (TOF) spectrographs have become a main staple in spaceborne mass spectrometry. They have largely replaced magnetic spectrometers, except when extremely high mass resolution is required to identify complex molecules, for example, in the vicinity of comets or in planetary atmospheres. In combination with electrostatic analyzers and often solid state detectors, TOF spectrographs have become key instruments to diagnose space plasma velocity distributions, mass, and ionic charge composition. With a variety of implementation schemes that also include isochronous electric field configurations, TOF spectrographs can respond to diverse science requirements. This includes a wide range in mass resolution to allow the separation of medium heavy isotopes or to simply provide distributions of the major species, such as H, He, and O, to obtain information on source tracers or mass fluxes. With a top-hat analyzer at the front end, or in combination with deflectors for three-axis stabilized spacecraft, the distribution function of ions can be obtained with good time resolution. Most recently, the reach of TOF ion mass spectrographs has been extended to include energetic neutral atoms. After selecting the arrival direction with mechanical collimation, followed by conversion to ions, adapted TOF sensors form a new branch of the spectrograph family tree. We review the requirements, challenges, and implementation schemes for ion and neutral atom spectrographs, including potential directions for the future, while largely avoiding overlap with complementary contributions in this special issue.

  16. ENAM'04 Fourth International Conference on Exotic Nuclei and Atomic Masses

    Energy Technology Data Exchange (ETDEWEB)

    Gross, C. J.; Nazarewicz, W.; Rykaczewski, K. P.

    2005-01-01

    The conference can trace its origins to the 1950s and 1960s with the Atomic Mass and Fundamental Constants (AMCO) and the Nuclei Far From Stability (NFFS) series of conferences. Held jointly in 1992, the conferences officially merged in 1995 and the fourth conference was held at Callaway Gardens in Pine Mountain, GA and was organized by the Physics Division at Oak Ridge National Laboratory. The conference covered a broad list of topics consisting of a series of invited and contributed presentation highlighting recent research in the following fields: Atomic masses, nuclear moments, and nuclear radii; Forms of radioactivity; Nuclear structure, nuclei at the drip lines, cluster phenomena; Reactions with radioactive ion beams; Nuclear astrophysics; Fundamental symmetries and interactions; Heaviest elements and fission; Radioactive ion beam production and experimental developments; Applications of exotic nuclei

  17. The 2003 update of antiproton mass by precision three-body calculation of antiprotonic helium atom

    CERN Document Server

    Kino, Y; Kudo, H

    2004-01-01

    The Particle Listings 2000 edition gave the recommended value of antiproton mass, for the first time, to be within 5 * 10/sup -7/ in the relative deviation from the proton mass; this can be a test of the CPT invariance. The value was derived by our precision 3-body calculation, using the Gaussian expansion method, to analyze the laser spectroscopy data of metastable states in antiprotonic helium atoms taken at CERN. The 2002 edition and the 2003 updated version reported an one-order smaller value, 6 * 10/sup -8/, based on further development of both the experiment and our calculation.

  18. A mass conserving level set method for detailed numerical simulation of liquid atomization

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Kun; Shao, Changxiao [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China); Yang, Yue [State Key Laboratory of Turbulence and Complex Systems, Peking University, Beijing 100871 (China); Fan, Jianren, E-mail: fanjr@zju.edu.cn [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China)

    2015-10-01

    An improved mass conserving level set method for detailed numerical simulations of liquid atomization is developed to address the issue of mass loss in the existing level set method. This method introduces a mass remedy procedure based on the local curvature at the interface, and in principle, can ensure the absolute mass conservation of the liquid phase in the computational domain. Three benchmark cases, including Zalesak's disk, a drop deforming in a vortex field, and the binary drop head-on collision, are simulated to validate the present method, and the excellent agreement with exact solutions or experimental results is achieved. It is shown that the present method is able to capture the complex interface with second-order accuracy and negligible additional computational cost. The present method is then applied to study more complex flows, such as a drop impacting on a liquid film and the swirling liquid sheet atomization, which again, demonstrates the advantages of mass conservation and the capability to represent the interface accurately.

  19. Measuring deuterium enrichment of glucose hydrogen atoms by gas chromatography/mass spectrometry.

    Science.gov (United States)

    Antoniewicz, Maciek R; Kelleher, Joanne K; Stephanopoulos, Gregory

    2011-04-15

    We developed a simple and accurate method for determining deuterium enrichment of glucose hydrogen atoms by electron impact gas chromatography mass spectrometry (GC/MS). First, we prepared 18 derivatives of glucose and screened over 200 glucose fragments to evaluate the accuracy and precision of mass isotopomer data for each fragment. We identified three glucose derivatives that gave six analytically useful ions: (1) glucose aldonitrile pentapropionate (m/z 173 derived from C4-C5 bond cleavage; m/z 259 from C3-C4 cleavage; m/z 284 from C4-C5 cleavage; and m/z 370 from C5-C6 cleavage); (2) glucose 1,2,5,6-di-isopropylidene propionate (m/z 301, no cleavage of glucose carbon atoms); and (3) glucose methyloxime pentapropionate (m/z 145 from C2-C3 cleavage). Deuterium enrichment at each carbon position of glucose was determined by least-squares regression of mass isotopomer distributions. The validity of the approach was tested using labeled glucose standards and carefully prepared mixtures of standards. Our method determines deuterium enrichment of glucose hydrogen atoms with an accuracy of 0.3 mol %, or better, without the use of any calibration curves or correction factors. The analysis requires only 20 μL of plasma, which makes the method applicable for studying gluconeogenesis using deuterated water in cell culture and animal experiments. © 2011 American Chemical Society

  20. Blind deconvolution of time-of-flight mass spectra from atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.J.S., E-mail: larsj@ifm.liu.se [Linköping University, Department of Physics, Chemistry, and Biology (IFM), Linköping SE-581 83 (Sweden); Thuvander, M.; Stiller, K. [Chalmers University of Technology, Department of Applied Physics, Gothenburg, SE-412 96 (Sweden); Odén, M.; Hultman, L. [Linköping University, Department of Physics, Chemistry, and Biology (IFM), Linköping SE-581 83 (Sweden)

    2013-09-15

    A major source of uncertainty in compositional measurements in atom probe tomography stems from the uncertainties of assigning peaks or parts of peaks in the mass spectrum to their correct identities. In particular, peak overlap is a limiting factor, whereas an ideal mass spectrum would have peaks at their correct positions with zero broadening. Here, we report a method to deconvolute the experimental mass spectrum into such an ideal spectrum and a system function describing the peak broadening introduced by the field evaporation and detection of each ion. By making the assumption of a linear and time-invariant behavior, a system of equations is derived that describes the peak shape and peak intensities. The model is fitted to the observed spectrum by minimizing the squared residuals, regularized by the maximum entropy method. For synthetic data perfectly obeying the assumptions, the method recovered peak intensities to within ±0.33at%. The application of this model to experimental APT data is exemplified with Fe–Cr data. Knowledge of the peak shape opens up several new possibilities, not just for better overall compositional determination, but, e.g., for the estimation of errors of ranging due to peak overlap or peak separation constrained by isotope abundances. - Highlights: • A method for the deconvolution of atom probe mass spectra is proposed. • Applied to synthetic randomly generated spectra the accuracy was ±0.33 at. • Application of the method to an experimental Fe–Cr spectrum is demonstrated.

  1. Anharmonicity of internal atomic oscillation and effective antineutrino mass evaluation from gaseous molecular tritium \\beta -decay

    CERN Document Server

    Lokhov, Alexey V

    2016-01-01

    Data analysis of the next generation effective antineutrino mass measurement experiment KATRIN requires reliable knowledge of systematic corrections. In particular, the width of the daughter molecular ion excitation spectrum rovibrational band should be known with a better then 1% precision. Very precise ab initio quantum calculations exist, and we compare them with the well known tritium molecule parameters within the framework of a phenomenological model. The rovibrational band width with accuracy of a few percent is interpreted as a result of the zero-point atomic oscillation in the harmonic potential. The Morse interatomic potential is used to investigate the impact of anharmonic atomic oscillations. The calculated corrections cannot account for the difference between the ab initio quantum calculations and the phenomenological model.

  2. A travelling wave model of ripple formation on ion bombarded surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi, E-mail: s.numazawa@hzdr.de; Smith, Roger, E-mail: R.Smith@lboro.ac.uk

    2013-05-15

    We present a mathematical model describing surface modification resulting from atomic motion after ion bombardment. The model considers only the defect production and recovery process induced by the local atom rearrangement and is essentially independent of surface topography changes formed by both sputtering and surface diffusion. A stable analytic, travelling wave solution is presented for a specific incident angle, which agrees with experimental observation excellently.

  3. The role of atomic hydrogen in regulating the scatter of the mass-metallicity relation

    Science.gov (United States)

    Brown, Toby; Cortese, Luca; Catinella, Barbara; Kilborn, Virginia

    2018-01-01

    In this paper, we stack neutral atomic hydrogen (H I) spectra for 9720 star-forming galaxies along the mass-metallicity relation. The sample is selected according to stellar mass (109 ≤ M⋆/M⊙ ≤ 1011) and redshift (0.02 ≤ z ≤ 0.05) from the overlap of the Sloan Digital Sky Survey and Arecibo Legacy Fast ALFA survey. We confirm and quantify the strong anticorrelation between H I mass and gas-phase metallicity at fixed stellar mass. Furthermore, we show for the first time that the relationship between gas content and metallicity is consistent between different metallicity estimators, contrary to the weaker trends found with star formation which are known to depend on the observational techniques used to derive oxygen abundances and star formation rates. When interpreted in the context of theoretical work, this result supports a scenario where galaxies exist in an evolving equilibrium between gas, metallicity and star formation. The fact that deviations from this equilibrium are most strongly correlated with gas mass suggests that the scatter in the mass-metallicity relation is primarily driven by fluctuations in gas accretion.

  4. van der Waals force between positronium and hydrogenic atoms Finite-mass corrections

    Science.gov (United States)

    Au, C. K.; Drachman, R. J.

    1986-01-01

    The Feshbach projection-operator formalism is used to derive the asymptotic effective interaction potential between two atoms. Beyond the usual van der Waals potential, falling like x exp -6, three x exp -8 terms are also obtained: an attractive dipole-quadrupole term (absent in the positronium-positronium case because of symmetry), a repulsive energy-dependent term, and a repulsive mass-dependent but energy-independent one. This last term was not obtained by Manson and Ritchie (1985) using an independent method.

  5. Building a multi-walled carbon nanotube-based mass sensor with the atomic force microscope

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Kuhle, A.; Marie, Rodolphe Charly Willy

    2005-01-01

    are used. The gold substrate is first covered with hydrophobic thiol molecules: octadecanthiol. The octadecanthiol molecules are then selectively removed from small areas by nanoshaving the gold substrate with the tip of an atomic force microscope (AFM) operating in contact mode. Hydrophilic thiols (2......We report an approach for building a mass sensor based on multi-walled carbon nanotubes (MWCNT). We propose a method with a great potential for the positioning of MWCNTs based on self-assembly onto patterned hydrophilic areas. For the experiments ultra flat mica substrates covered with gold...

  6. Nanometer-scale sharpening and surface roughening of ZnO nanorods by argon ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Shyamal, E-mail: shyamal@iitbbs.ac.in [School of Basic Sciences, Indian Institute of Technology, Bhubaneswar 751013 (India); Behera, Akshaya K. [School of Basic Sciences, Indian Institute of Technology, Bhubaneswar 751013 (India); Banerjee, Amarabha; Tribedi, Lokesh C. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Som, Tapobrata [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Ayyub, Pushan, E-mail: pushan@tifr.res.in [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2012-07-01

    We report the effects of exposing a hydrothermally grown, single crystalline ZnO nanorod array to a beam of 50 keV argon ions at room temperature. High resolution electron microscopy reveals that the ion bombardment results in a nanometer-scale roughening of the nanorod sidewalls, which were almost atomically flat in the pristine sample. Ion bombardment further causes the flat, Almost-Equal-To 100 nm diameter nanorod tips to get sharpened to ultrafine points less than 10 nm across. While tip sharpening is attributed to preferential sputtering, the formation of crystalline surface protuberances can be ascribed to surface instability due to curvature dependent sputtering and surface diffusion under argon-ion bombardment. Both the nanoscale roughening as well as the tip sharpening are expected to favorably impact a wide variety of applications, such as those involving catalysis, gas sensing, solar cells, field emission and gas discharge.

  7. [Atomic force microscopy fishing of gp120 on immobilized aptamer and its mass spectrometry identification].

    Science.gov (United States)

    Bukharina, N S; Ivanov, Yu D; Pleshakova, T O; Frantsuzov, P A; Andreeva, E Yu; Kaysheva, A L; Izotov, A A; Pavlova, T I; Ziborov, V S; Radko, S P; Archakov, A I

    2015-01-01

    A method of atomic force microscopy-based fishing (AFM fishing) has been developed for protein detection in the analyte solution using a chip with an immobilized aptamer. This method is based on the biospecific fishing of a target protein from a bulk solution onto the small AFM chip area with the immobilized aptamer to this protein used as the molecular probe. Such aptamer-based approach allows to increase an AFM image contrast compared to the antibody-based approach. Mass spectrometry analysis used after the biospecific fishing to identify the target protein on the AFM chip has proved complex formation. Use of the AFM chip with the immobilized aptamer avoids interference of the antibody and target protein peaks in a mass spectrum.

  8. Controlling residual hydrogen gas in mass spectra during pulsed laser atom probe tomography.

    Science.gov (United States)

    Kolli, R Prakash

    2017-01-01

    Residual hydrogen (H2) gas in the analysis chamber of an atom probe instrument limits the ability to measure H concentration in metals and alloys. Measuring H concentration would permit quantification of important physical phenomena, such as hydrogen embrittlement, corrosion, hydrogen trapping, and grain boundary segregation. Increased insight into the behavior of residual H2 gas on the specimen tip surface in atom probe instruments could help reduce these limitations. The influence of user-selected experimental parameters on the field adsorption and desorption of residual H2 gas on nominally pure copper (Cu) was studied during ultraviolet pulsed laser atom probe tomography. The results indicate that the total residual hydrogen concentration, HTOT, in the mass spectra exhibits a generally decreasing trend with increasing laser pulse energy and increasing laser pulse frequency. Second-order interaction effects are also important. The pulse energy has the greatest influence on the quantity HTOT, which is consistently less than 0.1 at.% at a value of 80 pJ.

  9. High depth resolution SIMS analysis using metal cluster complex ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, M; Kinno, T; Koike, M; Tanaka, H; Takeno, S [Corporate Research and Development Center, Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Fujiwara, Y; Kondou, K; Teranishi, Y; Nonaka, H; Fujimoto, T; Kurokawa, A; Ichimura, S [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba-shi, Ibaraki-ken 305-8568 (Japan)], E-mail: mitsuhiro.tomita@toshiba.co.jp

    2008-03-15

    SIMS depth profiles were measured using metal cluster complex ions of Ir{sub 4}(CO){sub 7}{sup +} as a primary ion beam in order to obtain high depth resolution. Depth resolution was evaluated as a function of primary ion species, energy and incident angle using a multiple boron delta-doped silicon sample. The depth resolution obtained using cluster ion bombardment was considerably better than that obtained by oxygen ion bombardment under the same bombardment condition due to reduction of atomic mixing in the depth. The best depth resolution was 0.9 nm under the bombardment condition of 5 keV, 45 deg. with oxygen flooding, which approaches the value measured with state of the art SIMS analyses. However, depth resolution was not improved by decreasing the cluster ion energy (less than 5 keV), even though the roughness of the sputtered surface was suppressed. The limit of depth resolution improvement may be caused by a carbon cover-layer that prevents the formation of surface oxide that buffers atomic mixing. To overcome this issue, it will be necessary to eliminate carbon from the cluster ion.

  10. Decay study of neutron-deficient La isotopes for atomic masses and nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki [Department of Materials Science, Japan Atomic Energy Research Institute, Takasaki, Gunma (JP)] [and others

    2000-06-01

    We report the decay spectroscopic studies with the TIARA-ISOL connected to an AVF cyclotron at the Takasaki site of JAERI between 1994 and 1998 under the Universities-JAERI Collaborative Research Project. Decay spectroscopic studies have been carried out for neutron-deficient La-Ce-Pr isotopes in the mass 120-130 region, which were prepared by on-line mass-separation following the fusion-evaporation reactions {sup 92,nat}Mo({sup 36}Ar, 3pxn). The {sup 125}Pr isotope was newly identified with a half-life of 3.3(7) s and its decay scheme was presented. The assignment of the 135.8 keV {gamma}-ray to the decay of {sup 125}Pr was supported by its coincidence with Ce X-rays and {beta}{sup +} rays. Low-spin states in {sup 124,} {sup 126,} {sup 128,} {sup 130}Ba fed by the {beta}{sup +}/EC decay of their La parents were investigated by means of the {gamma}-{gamma} angular correlation measurement. Q{sub EC}-values/atomic masses of neutron-deficient {sup 124-130}La were determined by {beta}{sup +}-ray maximum energy measurement. Half-lives of the first 2{sup +} state in {sup 122,} {sup 124,} {sup 126}Ba were measured using a {beta}-{gamma} delayed coincidence method. The experimental results obtained for the nuclear structure of the Ba isotopes are discussed in comparison with theory. (author)

  11. Mass attenuation coefficients and effective atomic numbers of biological compounds for gamma ray interactions

    Science.gov (United States)

    Gaikwad, Dhammajyot Kundlik; Pawar, Pravina P.; Selvam, T. Palani

    2017-09-01

    The mass attenuation coefficients (μ/ρ) for some enzymes, proteins, amino acids and fatty acids were measured at 122, 356, 511, 662, 1170, 1275 and 1330 keV photon energies, by performing transmission experiments using 57Co, 133Ba, 137Cs, 60Co and 22Na sources collimated to produce 0.52 cm diameter beams. A NaI (Tl) scintillation detector with energy resolution 8.2% at 663 keV was used for detection. The experimental values of (μ/ρ) were then used to determine the atomic cross section (σa), electronic cross section (σe), effective atomic number (Zeff) and electron density (Neff). It was observed that (μ/ρ), σa and σe decrease initially and then tends to be almost constant at higher energies. Values of Zeff and Neff were observed roughly constant with energy. The deviations in experimental results of radiological parameters were believed to be affected by physical and chemical environments. Experimental results of radiological parameters were observed in good agreement with WinXCom values.

  12. Three-dimensional molecular imaging using mass spectrometry and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wucher, Andreas [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany)], E-mail: andreas.wucher@uni-due.de; Cheng Juan; Zheng Leiliang; Willingham, David; Winograd, Nicholas [Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States)

    2008-12-15

    We combine imaging ToF-SIMS depth profiling and wide area atomic force microscopy to analyze a test structure consisting of a 300 nm trehalose film deposited on a Si substrate and pre-structured by means of a focused 15-keV Ga{sup +} ion beam. Depth profiling is performed using a 40-keV C{sub 60}{sup +} cluster ion beam for erosion and mass spectral data acquisition. A generic protocol for depth axis calibration is described which takes into account both lateral and in-depth variations of the erosion rate. By extrapolation towards zero analyzed lateral area, an 'intrinsic' depth resolution of about 8 nm is found which appears to be characteristic of the cluster-surface interaction process.

  13. Spontaneous Pattern Formation on Ion Bombarded Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Chason, Eric; Erlebacher, Jonah, Aziz, Michael J.; Floro, Jerrold A.; Sinclair, Michael B.

    1999-04-26

    Pattern formation on surfaces undergoing low-energy ion bombardment is a common phenomenon. Here, a recently developed in situ spectroscopic light scattering technique was used to monitor periodic ripple evolution on Si(001) during Ar(+) sputtering. Analysis of the rippling kinetics indicated that under high flux sputtering at low temperatures the concentration of mobile species on the surface is saturated, and, surprisingly, is both temperature and ion flux independent. This is due to an effect of ion collision cascades on the concentration of mobile species. This new understanding of surface dynamics during sputtering allowed us to measure straighforwardly the activation energy for atomic migration on the surface to be 1.2+0.1 eV. The technique is generalizable to any material, including high temperature and insulating materials for which surface migration energies are notoriously difficult to measure.

  14. Concept of effective atomic number and effective mass density in dual-energy X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bonnin, Anne, E-mail: annebonnin@free.fr [ESRF, 6 Jules Horowitz, F-38073 Grenoble Cedex (France); LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Duvauchelle, Philippe, E-mail: philippe.duvauchelle@insa-lyon.fr [LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Kaftandjian, Valérie [LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Ponard, Pascal [Thales Electron Devices SAS, 2 Rue Marcel Dassault, BP23 78141 Vélizy, Villacoublay Cedex (France)

    2014-01-01

    This paper focuses on dual-energy X-ray computed tomography and especially the decomposition of the measured attenuation coefficient in a mass density and atomic number basis. In particular, the concept of effective atomic number is discussed. Although the atomic number is well defined for chemical elements, the definition of an effective atomic number for any compound is not an easy task. After reviewing different definitions available in literature, a definition related to the method of measurement and X-ray energy, is suggested. A new concept of effective mass density is then introduced in order to characterize material from dual-energy computed tomography. Finally, this new concept and definition are applied on a simulated case, focusing on explosives identification in luggage.

  15. Selenosugar determination in porcine liver using multidimensional HPLC with atomic and molecular mass spectrometry.

    Science.gov (United States)

    Lu, Ying; Pergantis, Spiros A

    2009-01-01

    A methodology based on liquid chromatography coupled online with atomic and molecular mass spectrometry was developed for identifying trace amounts of the selenosugar methyl 2-acetamido-2-deoxy-1-seleno-β-D-galactopyranoside (SeGalNAc) in porcine liver, obtained from an animal that had not received selenium supplementation. Sample preparation was especially critical for the identification of SeGalNAc by molecular mass spectrometry. This involved liver extraction using a Tris buffer, followed by sequential centrifugations. The resulting cytosolic fraction was pre-concentrated and the low molecular weight selenium (LMWSe) fraction obtained from a size exclusion column was collected, concentrated, and subsequently analyzed using a tandem dual-column HPLC-ICP-MS system which consisted of strong cation exchange (SCX) and reversed phase (RP) columns coupled in tandem. Hepatocytosolic SeGalNAc was tentatively identified by retention time matching and spiking. Its identity was further confirmed by using the same type of chromatography on-line with atmospheric pressure chemical ionization tandem mass spectrometry operated in the selected reaction monitoring (SRM) mode. Four SRM transitions, characteristic of SeGalNAc, were monitored and their intensity ratios determined in order to confirm SeGalNAc identification. Instrument limits of detection for SeGalNAc by SCX-RP HPLC-ICP-MS and SCX-RP HPLC-APCI-MS/MS were 3.4 and 2.9 μg Se L(-1), respectively. Selenium mass balance analysis revealed that trace amounts of SeGalNAc, 2.16±0.94 μg Se kg(-1) liver (wet weight) were present in the liver cytosol, corresponding to 0.4% of the total Se content in the porcine liver.

  16. Numeral series hidden in the distribution of atomic mass of amino acids to codon domains in the genetic code.

    Science.gov (United States)

    Wohlin, Åsa

    2015-03-21

    The distribution of codons in the nearly universal genetic code is a long discussed issue. At the atomic level, the numeral series 2x(2) (x=5-0) lies behind electron shells and orbitals. Numeral series appear in formulas for spectral lines of hydrogen. The question here was if some similar scheme could be found in the genetic code. A table of 24 codons was constructed (synonyms counted as one) for 20 amino acids, four of which have two different codons. An atomic mass analysis was performed, built on common isotopes. It was found that a numeral series 5 to 0 with exponent 2/3 times 10(2) revealed detailed congruency with codon-grouped amino acid side-chains, simultaneously with the division on atom kinds, further with main 3rd base groups, backbone chains and with codon-grouped amino acids in relation to their origin from glycolysis or the citrate cycle. Hence, it is proposed that this series in a dynamic way may have guided the selection of amino acids into codon domains. Series with simpler exponents also showed noteworthy correlations with the atomic mass distribution on main codon domains; especially the 2x(2)-series times a factor 16 appeared as a conceivable underlying level, both for the atomic mass and charge distribution. Furthermore, it was found that atomic mass transformations between numeral systems, possibly interpretable as dimension degree steps, connected the atomic mass of codon bases with codon-grouped amino acids and with the exponent 2/3-series in several astonishing ways. Thus, it is suggested that they may be part of a deeper reference system. Copyright © 2015 The Author. Published by Elsevier Ltd.. All rights reserved.

  17. Mass Spectral Investigation on Toxins. I. Isolation, Purification, and Characterization of Hepatotoxins from Freshwater Blue-Green Algae (Cyanobacteria) by High-Performance Liquid Chromatography and Fast Atom Bombardment Mass Spectrometric Techniques.

    Science.gov (United States)

    1986-09-01

    analysis ’" methods in environmental samples. The hepatotoxins from laboratory cultures of M. aeruginosa Strain 7820,15 Anabena flos- aguae (A. 4flos...flos- aguae S-23-g-1l (8 lug) F1 The results from the amino acid analysis using the Llqui-Mat Analyzer are listed in Table 2. The elution times of the...Runnegar, M.T.C., and Huynh, V.L. Effec- tiveness of Activated Carbon in the Removal of Algal Toxin from Potable Water Supplies: A Pilot Plant

  18. On the Mass of Atoms in Molecules: Beyond the Born-Oppenheimer Approximation

    Directory of Open Access Journals (Sweden)

    Arne Scherrer

    2017-08-01

    Full Text Available Describing the dynamics of nuclei in molecules requires a potential energy surface, which is traditionally provided by the Born-Oppenheimer or adiabatic approximation. However, we also need to assign masses to the nuclei. There, the Born-Oppenheimer picture does not account for the inertia of the electrons, and only bare nuclear masses are considered. Nowadays, experimental accuracy challenges the theoretical predictions of rotational and vibrational spectra and requires the participation of electrons in the internal motion of the molecule. More than 80 years after the original work of Born and Oppenheimer, this issue has still not been solved, in general. Here, we present a theoretical and numerical framework to address this problem in a general and rigorous way. Starting from the exact factorization of the electron-nuclear wave function, we include electronic effects beyond the Born-Oppenheimer regime in a perturbative way via position-dependent corrections to the bare nuclear masses. This maintains an adiabaticlike point of view: The nuclear degrees of freedom feel the presence of the electrons via a single potential energy surface, whereas the inertia of electrons is accounted for and the total mass of the system is recovered. This constitutes a general framework for describing the mass acquired by slow degrees of freedom due to the inertia of light, bounded particles; thus, it is applicable not only in electron-nuclear systems but in light-heavy nuclei or ions as well. We illustrate this idea with a model of proton transfer, where the light particle is the proton and the heavy particles are the oxygen atoms to which the proton is bounded. Inclusion of the light-particle inertia allows us to gain orders of magnitude in accuracy. The electron-nuclear perspective is adopted, instead, to calculate position-dependent mass corrections using density functional theory for a few polyatomic molecules at their equilibrium geometry. These data can

  19. Unconventional thermal transport enhancement with large atom mass: a comparative study of 2D transition dichalcogenides

    Science.gov (United States)

    Wang, Huimin; Qin, Guangzhao; Li, Guojian; Wang, Qiang; Hu, Ming

    2018-01-01

    2D layered transition dichalcogenides have attracted tremendous attention for their excellent properties and multifarious applications. In particular, NbSe2 and TaSe2 are the canonical systems to study superconductivity and charge density waves. Here, we perform a comparative study of the thermal transport properties of 2D NbSe2 and TaSe2 for both 1T and 2H phases based on first-principles calculations. Usually, the lattice thermal conductivity ({{κ }L} ) is smaller with larger average atom mass. However, it is contrary for the comparison between TaSe2 and NbSe2, despite the heavier Ta than Nb. The abnormally larger {{κ }L} of TaSe2 originates from the weakened phonon–phonon scattering due to the combination of large phonon bandgap and bunching of the acoustic phonon branches, which is caused by the larger mass difference. On one hand, the large bandgap hinders the acoustic–optical phonon scattering. On the other hand, the bunching of the acoustic phonon branches hampers Umklapp process by weakening the high frequency acoustic–acoustic phonon scattering. The special characteristics of phonon transport are further conformed by mode level analysis and scattering channels of phonon–phonon scattering. Moreover, lower κ L of 1T phase for both Nb and Ta selenides compared to 2H phase are also reported, which stems from the stronger anharmonicity.

  20. Transgenic sorghum plants via microprojectile bombardment.

    OpenAIRE

    Casas, A M; Kononowicz, A K; Zehr, U B; Tomes, D T; Axtell, J. D.; Butler, L. G.; Bressan, R. A.; Hasegawa, P M

    1993-01-01

    Transgenic sorghum plants have been obtained after microprojectile bombardment of immature zygotic embryos of a drought-resistant sorghum cultivar, P898012. DNA delivery parameters were optimized based on transient expression of R and C1 maize anthocyanin regulatory elements in scutellar cells. The protocol for obtaining transgenic plants consists of the delivery of the bar gene to immature zygotic embryos and the imposition of bialaphos selection pressure at various stages during culture, fr...

  1. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry

    Science.gov (United States)

    Montaser, A.

    This research follows a multifaceted approach, from theory to practice, to the investigation and development of novel helium plasmas, sample introduction systems, and diagnostic techniques for atomic and mass spectrometries. During the period January 1994 - December 1994, four major sets of challenging research programs were addressed that each included a number of discrete but complementary projects: (1) The first program is concerned with fundamental and analytical investigations of novel atmospheric-pressure helium inductively coupled plasmas (He ICPS) that are suitable for the atomization-excitation-ionization of elements, especially those possessing high excitation and ionization energies, for the purpose of enhancing sensitivity and selectivity of analytical measurements. (2) The second program includes simulation and computer modeling of He ICPS. The aim is to ease the hunt for new helium plasmas by predicting their structure and fundamental and analytical properties, without incurring the enormous cost for extensive experimental studies. (3) The third program involves spectroscopic imaging and diagnostic studies of plasma discharges to instantly visualize their prevailing structures, to quantify key fundamental properties, and to verify predictions by mathematical models. (4) The fourth program entails investigation of new, low-cost sample introduction systems that consume micro- to nanoliter quantity of sample solution in plasma spectrometries. A portion of this research involves development and applications of novel diagnostic techniques suitable for probing key fundamental properties of aerosol prior to and after injection into high-temperature plasmas. These efforts, still in progress, collectively offer promise of solving singularly difficult analytical problems that either exist now or are likely to arise in the future in the various fields of energy generation, environmental pollution, material science, biomedicine and nutrition.

  2. Determination of mercury in hair: Comparison between gold amalgamation-atomic absorption spectrometry and mass spectrometry.

    Science.gov (United States)

    Domanico, Francesco; Forte, Giovanni; Majorani, Costanza; Senofonte, Oreste; Petrucci, Francesco; Pezzi, Vincenzo; Alimonti, Alessandro

    2017-09-01

    Mercury is a heavy metal that causes serious health problems in exposed subjects. The most toxic form, i.e., methylmercury (MeHg), is mostly excreted through human hair. Numerous analytical methods are available for total Hg analysis in human hair, including cold vapour atomic fluorescence spectrometry (CV-AFS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). The aim of the study was to compare the TDA-AAS with the ICP-MS in the Hg quantification in human hair. After the washing procedure to minimize the external contamination, from each hair sample two aliquots were taken; the first was used for direct analysis of Hg by TDA-AAS and the second was digested for Hg determination by the ICP-MS. Results indicated that the two data sets were fully comparable (median; TDA-AAS, 475ngg -1 ; ICP-MS, 437ngg -1 ) and were not statistically different (Mann-Whitney test; p=0.44). The two techniques presented results with a good coefficient of correlation (r=0.94) despite different operative ranges and method limits. Both techniques satisfied internal performance requirements and the parameters for method validation resulting sensitive, precise and reliable. Finally, the use of the TDA-AAS can be considered instead of the ICP-MS in hair analysis in order to reduce sample manipulation with minor risk of contamination, less time consuming due to the absence of the digestion step and cheaper analyses. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. Bombardment of gas molecules on single graphene layer at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Murugesan, Ramki [School of Mechanical and Aerospace Engineering, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Park, Jae Hyun [Department of Aerospace and System Engineering and Research Center for Aircraft Parts Technology, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Ha, Dong Sung [Future Propulsion Center, Agency for Defense Development, Daejeon 305-600 (Korea, Republic of)

    2014-12-09

    Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H{sub 2}), we will concentrate on the impact by realistic molecules (e.g., CO{sub 2} and H{sub 2}O). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

  4. Influence of ion-beam bombardment on the optical properties of LDPE polymer blends

    Science.gov (United States)

    Rizk, R. A. M.; Abdul-Kader, A. M.; Ali, M.; Ali, Z. I.

    2008-10-01

    Ion beams have been found to be widely applicable in improving the structure and physical properties of polymers. In this paper, the effect of ion bombardment on the optical properties of low density polyethylene (LDPE)/styrene butadiene rubber (SBR) blend (LDPE/SBR) was studied. Polymer samples were bombarded with 130 keV He and 320 keV Ar ions to fluencies ranging from 1 × 1013 to 2 × 1016 ions cm-2. The pristine and ion beam bombarded samples were investigated using ultraviolet-visible (UV-Vis) spectrophotometry. The optical band gap (Eg) was decreased from ~2.3 to ~1.22 eV for the pristine sample and those samples bombarded with He and Ar ions at the highest fluence. The change in the optical gap indicates the presence of a gradual phase transition for the polymer blends. With increasing ion fluence, a decrease in both the energy gap and the activation energy was observed. The number of carbon atoms (N) in a formed cluster is found to be directly proportional to ion fluence and is determined according to the modified Tauc equation.

  5. Antiproton–to–electron mass ratio determined by two-photon laser spectroscopy of antiprotonic helium atoms

    Directory of Open Access Journals (Sweden)

    Sótér A.

    2014-03-01

    Full Text Available The ASACUSA collaboration of CERN has recently carried out two-photon laser spectroscopy of antiprotonic helium atoms. Three transition frequencies were determined with fractional precisions of 2.3–5 parts in 109. By comparing the results with three-body QED calculations, the antiproton-to-electron mass ratio was determined as 1836.1526736(23.

  6. Proton bombarded reactions of Calcium target nuclei

    Directory of Open Access Journals (Sweden)

    Tel Eyyup

    2017-01-01

    Full Text Available In this study, proton bombarded nuclear reactions calculations of Calcium target nuclei have been investigated in the incident proton energy range of 1–50 MeV. The excitation functions for 40Ca target nuclei reactions have been calculated by using PCROSS nuclear reaction calculation code. Weisskopf-Ewing and the full exciton models were used for equilibrium and for pre-equilibrium calculations, respectively. The excitation functions for 40Ca target nuclei reactions (p,α, (p,n, (p,p have been calculated using the semi-empirical formula Tel et al. [5].

  7. Surface Morphologies of Ti and Ti-Al-V Bombarded by 1.0-MeV Au+ Ions

    Science.gov (United States)

    Garcia, M. A.; Rickards, J.; Cuerno, R.; Trejo-Luna, R.; Cañetas-Ortega, J.; de la Vega, L. R.; Rodríguez-Fernández, L.

    2017-12-01

    Ion implantation is known to enhance the mechanical properties of biomaterials such as, e.g., the wear resistance of orthopedic joints. Increasing the surface area of implants may likewise improve their integration with, e.g., bone tissue, which requires surface features with sizes in the micron range. Ion implantation of biocompatible metals has recently been demonstrated to induce surface ripples with wavelengths of a few microns. However, the physical mechanisms controlling the formation and characteristics of these patterns are yet to be understood. We bombard Ti and Ti-6Al-4V surfaces with 1.0-MeV Au+ ions. Analysis by scanning electron and atomic force microscopies shows the formation of surface ripples with typical dimensions in the micron range, with potential indeed for biomedical applications. Under the present specific experimental conditions, the ripple properties are seen to strongly depend on the fluence of the implanted ions while being weakly dependent on the target material. Moreover, by examining experiments performed for incidence angle values θ =8 ° , 23°, 49°, and 67°, we confirm the existence of a threshold incidence angle for (ripple) pattern formation. Surface indentation is also used to study surface features under additional values of θ , agreeing with our single-angle experiments. All properties of the surface structuring process are very similar to those found in the production of surface nanopatterns under low-energy ion bombardment of semiconductor targets, in which the stopping power is dominated by nuclear contributions, as in our experiments. We consider a continuum model that combines the effects of various physical processes as originally developed in that context, with parameters that we estimate under a binary-collision approximation. Notably, reasonable agreement with our experimental observations is achieved, even under our high-energy conditions. Accordingly, in our system, ripple formation is determined by mass

  8. Effect of substrate thickness on ejection of phenylalanine molecules adsorbed on free-standing graphene bombarded by 10 keV C60

    Science.gov (United States)

    Golunski, M.; Verkhoturov, S. V.; Verkhoturov, D. S.; Schweikert, E. A.; Postawa, Z.

    2017-02-01

    Molecular dynamics computer simulations have been employed to investigate the effect of substrate thickness on the ejection mechanism of phenylalanine molecules deposited on free-standing graphene. The system is bombarded from the graphene side by 10 keV C60 projectiles at normal incidence and the ejected particles are collected both in transmission and reflection directions. It has been found that the ejection mechanism depends on the substrate thickness. At thin substrates mostly organic fragments are ejected by direct collisions between projectile atoms and adsorbed molecules. At thicker substrates interaction between deforming topmost graphene sheet and adsorbed molecules becomes more important. As this process is gentle and directionally correlated, it leads predominantly to ejection of intact molecules. The implications of the results to a novel analytical approach in Secondary Ion Mass Spectrometry based on ultrathin free-standing graphene substrates and a transmission geometry are discussed.

  9. Underground atom gradiometer array for mass distribution monitoring and advanced geodesy

    Science.gov (United States)

    Canuel, B.

    2015-12-01

    After more than 20 years of fundamental research, atom interferometers have reached sensitivity and accuracy levels competing with or beating inertial sensors based on different technologies. Atom interferometers offer interesting applications in geophysics (gravimetry, gradiometry, Earth rotation rate measurements), inertial sensing (submarine or aircraft autonomous positioning), metrology (new definition of the kilogram) and fundamental physics (tests of the standard model, tests of general relativity). Atom interferometers already contributed significantly to fundamental physics by, for example, providing stringent constraints on quantum-electrodynamics through measurements of the hyperfine structure constant, testing the Equivalence Principle with cold atoms, or providing new measurements for the Newtonian gravitational constant. Cold atom sensors have moreover been established as key instruments in metrology for the new definition of the kilogram or through international comparisons of gravimeters. The field of atom interferometry (AI) is now entering a new phase where very high sensitivity levels must be demonstrated, in order to enlarge the potential applications outside atomic physics laboratories. These applications range from gravitational wave (GW) detection in the [0.1-10 Hz] frequency band to next generation ground and space-based Earth gravity field studies to precision gyroscopes and accelerometers. The Matter-wave laser Interferometric Gravitation Antenna (MIGA) presented here is a large-scale matter-wave sensor which will open new applications in geoscience and fundamental physics. The MIGA consortium gathers 18 expert French laboratories and companies in atomic physics, metrology, optics, geosciences and gravitational physics, with the aim to build a large-scale underground atom-interferometer instrument by 2018 and operate it till at least 2023. In this paper, we present the main objectives of the project, the status of the construction of the

  10. Optical memory based on quantized atomic center-of-mass motion.

    Science.gov (United States)

    Lopez, J P; de Almeida, A J F; Felinto, D; Tabosa, J W R

    2017-11-01

    We report a new type of optical memory using a pure two-level system of cesium atoms cooled by the magnetically assisted Sisyphus effect. The optical information of a probe field is stored in the coherence between quantized vibrational levels of the atoms in the potential wells of a 1-D optical lattice. The retrieved pulse shows Rabi oscillations with a frequency determined by the reading beam intensity and are qualitatively understood in terms of a simple theoretical model. The exploration of the external degrees of freedom of an atom may add another capability in the design of quantum-information protocols using light.

  11. Self-heating effect induced by ion bombardment on polycrystalline ...

    Indian Academy of Sciences (India)

    to the self-heating effect by energy exchange between incident ions and Al surface, and the suppression by conti- nuous ion bombardment with a .... The temperature of the water-cooled substrate holder was fixed at 15. ◦. C. The Ar. + ... as the interaction between continuous ion bombardment and isotropic diffusion on the ...

  12. Beyond Bombardment: Subjectivity, Visual Culture, and Art Education

    Science.gov (United States)

    Eisenhauer, Jennifer F.

    2006-01-01

    Beginning with an understanding of visual culture as a postmodern discourse, this article argues for more focused attention to how visual culture presents a critical rethinking of subjectivity within art education. Through an analysis of a language of bombardment, a discourse that positions the subject as bombarded by media messages, this article…

  13. Efficient mass-selective three-photon ionization of zirconium atoms

    Science.gov (United States)

    Page, Ralph H.

    1994-01-01

    In an AVLIS process, .sup.91 Zr is selectively removed from natural zirconium by a three-step photoionization wherein Zr atoms are irradiated by a laser beam having a wavelength .lambda..sub.1, selectively raising .sup.91 Zr atoms to an odd-parity E.sub.1 energy level in the range of 16000-19000 cm.sup.-1, are irradiated by a laser beam having a wavelength .lambda..sub.2 to raise the atoms from an E.sub.l level to an even-parity E.sub.2 energy level in the range of 35000-37000 cm.sup.-1 and are irradiated by a laser beam having a wavelength .lambda..sub.3 to cause a resonant transition of atoms from an E.sub.2 level to an autoionizing level above 53506 cm.sup.-1. .lambda..sub.3 wavelengths of 5607, 6511 or 5756 .ANG. will excite a zirconium atom from an E.sub.2 energy state of 36344 cm.sup.-1 to an autoionizing level; a .lambda..sub.3 wavelength of 5666 .ANG. will cause an autoionizing transition from an E.sub.2 level of 36068 cm.sup.-1 ; and a .lambda. .sub.3 wavelength of 5662 .ANG. will cause an ionizing resonance of an atom at an E.sub.2 level of 35904 cm.sup.-1.

  14. Influence of the atomic mass of the background gas on laser ablation plume propagation

    DEFF Research Database (Denmark)

    Amoruso, Salvatore; Schou, Jørgen; Lunney, James G.

    2008-01-01

    A combination of time-of-flight ion probe measurements and gas dynamical modeling has been used to investigate the propagation of a laser ablation plume in gases of different atomic/molecular weight. The pressure variation of the ion time-of-flight was found to be well described by the gas...... dynamical model of Predtechensky and Mayorov (Appl. Supercond. 1:2011, 1993). In particular, the model describes how the pressure required to stop the plume in a given distance depends on the atomic/molecular weight of the gas, which is a feature that cannot be explained by standard point...

  15. Filtrates and Residues: Measuring the Atomic or Molecular Mass of a Gas with a Tire Gauge and a Butane Lighter Fluid Can.

    Science.gov (United States)

    Bodner, George M.; Magginnis, Lenard J.

    1985-01-01

    Describes the use of an inexpensive apparatus (based on a butane lighter fluid can and a standard tire pressure gauge) in measuring the atomic/molecular mass of an unknown gas and in demonstrating the mass of air or the dependence of pressure on the mass of a gas. (JN)

  16. Formation of oxides and segregation of mobile atoms during SIMS profiling of Si with oxygen ions

    Energy Technology Data Exchange (ETDEWEB)

    Petravic, M.; Williams, J.S.; Svensson, B.G.; Conway, M. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1993-12-31

    An oxygen beam is commonly used in secondary ion mass spectroscopy (SIMS) analysis to enhance the ionization probability for positive secondary ions. It has been observed, however, that this technique produces in some cases a great degradation of depth resolution. The most pronounced effects have been found for impurities in silicon under oxygen bombardment at angles of incidence smaller than {approx} 30 deg from the surface normal. A new approach is described which involved broadening of SIMS profiles for some mobile atoms, such as Cu, Ni and Au, implanted into silicon. The anomalously large broadening is explained in terms of segregation at a SiO{sub 2}/Si interface formed during bombardment with oxygen at impact angles less than 30 deg. 2 refs., 1 tab., 4 figs.

  17. Data correlation in on-line solid-phase extraction-gas chromatography-atomic emission/mass spectrometric detection of unknown microcontaminants

    NARCIS (Netherlands)

    Hankemeier, Th.; Rozenbrand, J.; Abhadur, M.; Vreuls, J.J.; Brinkman, U.A.Th.

    1998-01-01

    A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction (SPE) was coupled on-line to both GC

  18. Atmospheric-pressure solution-cathode glow discharge: A versatile ion source for atomic and molecular mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Andrew J. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Williams, Kelsey L. [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Hieftje, Gary M. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Shelley, Jacob T., E-mail: shellj@rpi.edu [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States)

    2017-01-15

    An atmospheric-pressure solution-cathode glow discharge (SCGD) has been evaluated as an ion source for atomic, molecular, and ambient desorption/ionization mass spectrometry. The SCGD consists of a direct-current plasma, supported in the ambient air in the absence of gas flows, and sustained upon the surface of a flowing liquid cathode. Analytes introduced in the flowing liquid, as an ambient gas, or as a solid held near the plasma are vaporized and ionized by interactions within or near the discharge. Introduction of acidic solutions containing metal salts produced bare elemental ions as well as H{sub 2}O, OH{sup −} and NO{sub 3}{sup −} adducts. Detection limits for these elemental species ranged from 0.1 to 4 ppb, working curves spanned more than 4 orders of linear dynamic range, and precision varied between 5 and 16% relative standard deviation. Small organic molecules were also efficiently ionized from solution, and both the intact molecular ion and fragments were observed in the resulting SCGD mass spectra. Fragmentation of molecular species was found to be tunable; high discharge currents led to harder ionization, while low discharge currents produced stronger molecular-ion signals. Ambient gases and solids, desorbed by the plasma from a glass probe, were also readily ionized by the SCGD. Indeed, strong analyte signals were obtained from solid samples placed at least 2 cm from the plasma. These findings indicate that the SCGD might be useful also for ambient desorption/ionization mass spectrometry. Combined with earlier results that showed the SCGD is useful for ionization of labile biomolecules, the results here indicate that the SCGD is a highly versatile ion source capable of providing both elemental and molecular mass-spectral information. - Highlights: • Solution-cathode glow discharge used as an ionization source for mass spectrometry. • SCGD-MS can provide atomic as well as intact molecular mass spectra. • Atomic limits of detection range

  19. Influence of the atomic mass of the background gas on laser ablation plume propagation

    Science.gov (United States)

    Amoruso, Salvatore; Schou, Jørgen; Lunney, James G.

    2008-09-01

    A combination of time-of-flight ion probe measurements and gas dynamical modeling has been used to investigate the propagation of a laser ablation plume in gases of different atomic/molecular weight. The pressure variation of the ion time-of-flight was found to be well described by the gas dynamical model of Predtechensky and Mayorov (Appl. Supercond. 1:2011, 1993). In particular, the model describes how the pressure required to stop the plume in a given distance depends on the atomic/molecular weight of the gas, which is a feature that cannot be explained by standard point-blast-wave descriptions of laser ablation plume expansion in gas.

  20. Transgenic sorghum plants via microprojectile bombardment.

    Science.gov (United States)

    Casas, A M; Kononowicz, A K; Zehr, U B; Tomes, D T; Axtell, J D; Butler, L G; Bressan, R A; Hasegawa, P M

    1993-12-01

    Transgenic sorghum plants have been obtained after microprojectile bombardment of immature zygotic embryos of a drought-resistant sorghum cultivar, P898012. DNA delivery parameters were optimized based on transient expression of R and C1 maize anthocyanin regulatory elements in scutellar cells. The protocol for obtaining transgenic plants consists of the delivery of the bar gene to immature zygotic embryos and the imposition of bialaphos selection pressure at various stages during culture, from induction of somatic embryogenesis to rooting of regenerated plantlets. One in about every 350 embryos produced embryogenic tissues that survived bialaphos treatment; six transformed callus lines were obtained from three of the eight sorghum cultivars used in this research. Transgenic (T0) plants were obtained from cultivar P898012 (two independent transformation events). The presence of the bar and uidA genes in the T0 plants was confirmed by Southern blot analysis of genomic DNA. Phosphinothricin acetyltransferase activity was detected in extracts of the T0 plants. These plants were resistant to local application of the herbicide Ignite/Basta, and the resistance was inherited in T1 plants as a single dominant locus.

  1. Strongly reduced fragmentation and soft emission processes in sputtered ion formation from amino acid films under large Ar(n)+ (n ≤ 2200) cluster ion bombardment.

    Science.gov (United States)

    Gnaser, Hubert; Ichiki, Kazuya; Matsuo, Jiro

    2012-01-15

    The analysis of organic and biological substances by secondary-ion mass spectrometry (SIMS) has greatly benefited from the use of cluster ions as primary bombarding species. Thereby, depth profiling and three-dimensional (3D) imaging of such systems became feasible. Large Ar(n)(+) cluster ions may constitute a further improvement in this direction. To explore this option, size-selected Ar(n)(+) cluster ions with 300 ≤ n ≤ 2200 (bombarding energies 5.5 and 11 keV) were used to investigate the emission of positive secondary ions from four amino acid specimens (arginine, glycine, phenylalanine, and tyrosine) by time-of-flight SIMS. For all cluster sizes, the protonated molecule of the respective amino acid is observed in the mass spectra. With increasing cluster size the number of fragment ions decreases strongly in relation to the intact molecules, to the extent that the fraction of fragment ions amounts to less than 10% in some cases. Such 'soft' emission processes also lead the ejection of dimers and even multimers of the amino acid molecules. In the case of the phenylalanine, secondary ion species composed of up to at least seven phenylalanine moieties were observed. Tentatively, the ionization probability of the emitted molecules is envisaged to depend on the presence of free protons in the emission zone. Their number can be expected to decrease concurrently with the decreasing amount of fragmentation for large Ar(n)(+) cluster ions (i.e. for low energies per cluster atom). Copyright © 2011 John Wiley & Sons, Ltd.

  2. Test the accuracy of the Dubna phenomenological model of the masses of the atomic nuclei

    OpenAIRE

    Mavrodiev, Strachimir Cht.

    2017-01-01

    In this paper is presented the reliability test the numerical generalization of Bethe-Weizsacker mass formula which describes the values of measured 2654 nuclei masses in AME2012 nuclear database: https://www-nds.iaea.org/amdc/, with accuracy in the interval (-1.90,1.80) MeV, for the nulear with mass number A=2(1,1) to 294(117,177). In the analyzed generalization of the Bethe-Weizsacker formula the little correction of proton and neutron magic numbers and boundaries of their influence was der...

  3. Atomic masses above /sup 146/Gd derived from a shell model analysis of high spin states

    CERN Document Server

    Blomqvist, J; Daly, P J; Kleinheinz, P

    1981-01-01

    Using extensive spectroscopic data on high spin states involving aligned valence nucleons in very neutron deficient nuclei above /sup 146/Gd the authors have derived the ground state masses of /sup 146 /Gd, /sup 147,148/Tb, /sup 148,149,150/Dy, /sup 149,150,151/Ho, and /sup 150,151,152/Er from a shell model analysis. The mass values show a pronounced irregularity in the two-proton separation energies at /sup 146/Gd. The results also link nine alpha -decay chains to the known masses. (0 refs).

  4. Polymeric spatial resolution test patterns for mass spectrometry imaging using nano-thermal analysis with atomic force microscopy.

    Science.gov (United States)

    Tai, Tamin; Kertesz, Vilmos; Lin, Ming-Wei; Srijanto, Bernadeta R; Hensley, Dale K; Xiao, Kai; Van Berkel, Gary J

    2017-07-30

    As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the nanometer regime, finding readily available or easily made resolution reference materials has become particularly challenging for molecular imaging purposes. This paper describes the fabrication, characterization and use of vertical line array polymeric spatial resolution test patterns for nano-thermal analysis/atomic force microscopy/mass spectrometry chemical imaging. Test patterns of varied line width (0.7 or 1.0 μm) and spacing (0.7 or 1.0 μm) were created in an ~1-μm-thick poly(methyl methacrylate) thin film using electron beam lithography. The patterns were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy topography and nano-thermal analysis/mass spectrometry imaging. The efficacy of these polymeric test patterns for the advancement of chemical imaging techniques was illustrated by their use to judge the spatial resolution improvement achieved by heating the ionization interface of the current instrument platform. The spatial resolution of the mass spectral chemical images was estimated to be 1.4 μm, based on the ability to statistically distinguish 0.7-μm-wide lines separated by 0.7-μm-wide spacings in those images when the interface cross was heated to 200°C. This work illustrates that e-beam lithography is a viable method to create spatial resolution test patterns in a thin film of high molecular weight polymer to allow unbiased judgment of intra-laboratory advancement and/or inter-laboratory comparison of instrument advances in nano-thermal analysis/atomic force microscopy/mass spectrometry chemical imaging. Published in 2017. This article is a U.S. Government work and is in the public domain in the USA. Published in 2017. This article is a U.S. Government work and is in the public domain in the USA.

  5. Compositional Evolution of Saturn's Rings Due to Meteoroid Bombardment

    Science.gov (United States)

    Cuzzi, J.; Estrada, P.; Young, Richard E. (Technical Monitor)

    1997-01-01

    In this paper we address the question of compositional evolution in planetary ring systems subsequent to meteoroid bombardment. The huge surface area to mass ratio of planetary rings ensures that this is an important process, even with current uncertainties on the meteoroid flux. We develop a new model which includes both direct deposition of extrinsic meteoritic "pollutants", and ballistic transport of the increasingly polluted ring material as impact ejecta. Our study includes detailed radiative transfer modeling of ring particle spectral reflectivities based on refractive indices of realistic constituents. Voyager data have shown that the lower optical depth regions in Saturn's rings (the C ring and Cassini Division) have darker and less red particles than the optically thicken A and B rings. These coupled structural-compositional groupings have never been explained; we present and explore the hypothesis that global scale color and compositional differences in the main rings of Saturn arise naturally from extrinsic meteoroid bombardment of a ring system which was initially composed primarily, but not entirely, of water ice. We find that the regional color and albedo differences can be understood if all ring material was initially identical (primarily water ice, based on other data, but colored by tiny amounts of intrinsic reddish, plausibly organic, absorber) and then evolved entirely by addition and mixing of extrinsic, nearly neutrally colored. plausibly carbonaceous material. We further demonstrate that the detailed radial profile of color across the abrupt B ring - C ring boundary can.constrain key unknown parameters in the model. Using new alternates of parameter values, we estimate the duration of the exposure to extrinsic meteoroid flux of this part of the rings, at least, to be on the order of 10(exp 8) years. This conclusion is easily extended by inference to the Cassini Division and its surroundings as well. This geologically young "age" is compatible

  6. Combined chemical and topographic imaging at atmospheric pressure via microprobe laser desorption/ionization mass spectrometry-atomic force microscopy.

    Science.gov (United States)

    Bradshaw, James A; Ovchinnikova, Olga S; Meyer, Kent A; Goeringer, Douglas E

    2009-12-01

    The operational characteristics and imaging performance are described for a new instrument comprising an atomic force microscope coupled with a pulsed laser and a linear ion trap mass spectrometer. The operating mode of the atomic force microscope is used to produce topographic surface images having sub-micrometer spatial and height resolution. Spatially resolved mass spectra of ions, produced from the same surface via microprobe-mode laser desorption/ionization at atmospheric pressure, are also used to create a 100 x 100 microm chemical image. The effective spatial resolution of the image (approximately 2 microm) was constrained by the limit of detection (estimated to be 10(9)-10(10) molecules) rather than by the diameter of the focused laser spot or the step size of the sample stage. The instrument has the potential to be particularly useful for surface analysis scenarios in which chemical analysis of targeted topographic features is desired; consequently, it should have extensive application in a number of scientific areas. Because the number density of desorbed neutral species in laser desorption/ionization is known to be orders-of-magnitude greater than that of ions, it is expected that improvements in imaging performance can be realized by implementation of post-ionization methods.

  7. Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

    CERN Document Server

    Trassinelli, M; Borchert, G; Dax, A; Egger, J P; Gotta, D; Hennebach, M; Indelicato, P; Liu, Y -W; Manil, B; Nelms, N; Simons, L M; Wells, A

    2016-01-01

    The $5g-4f$ transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\\,bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077\\,$\\pm$\\,0.00018)\\,MeV/c$^{2}$ ($\\pm$\\,1.3ppm) is derived for the mass of the negatively charged pion, which is 4.2ppm larger than the present world average.

  8. Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

    Directory of Open Access Journals (Sweden)

    M. Trassinelli

    2016-08-01

    Full Text Available The 5g−4f transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen–oxygen mixture at 1.4 bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077 ± 0.00018 MeV/c2 (± 1.3 ppm is derived for the mass of the negatively charged pion, which is 4.2 ppm larger than the present world average.

  9. In situ spatial organization of Potato virus A coat protein subunits as assessed by tritium bombardment.

    Science.gov (United States)

    Baratova, L A; Efimov, A V; Dobrov, E N; Fedorova, N V; Hunt, R; Badun, G A; Ksenofontov, A L; Torrance, L; Järvekülg, L

    2001-10-01

    Potato virus A (PVA) particles were bombarded with thermally activated tritium atoms, and the intramolecular distribution of the label in the amino acids of the coat protein was determined to assess their in situ steric accessibility. This method revealed that the N-terminal 15 amino acids of the PVA coat protein and a region comprising amino acids 27 to 50 are the most accessible at the particle surface to labeling with tritium atoms. A model of the spatial arrangement of the PVA coat protein polypeptide chain within the virus particle was derived from the experimental data obtained by tritium bombardment combined with predictions of secondary-structure elements and the principles of packing alpha-helices and beta-structures in proteins. The model predicts three regions of tertiary structure: (i) the surface-exposed N-terminal region, comprising an unstructured N terminus of 8 amino acids and two beta-strands, (ii) a C-terminal region including two alpha-helices, as well as three beta-strands that form a two-layer structure called an abCd unit, and (iii) a central region comprising a bundle of four alpha-helices in a fold similar to that found in tobacco mosaic virus coat protein. This is the first model of the three-dimensional structure of a potyvirus coat protein.

  10. Measurement of the charged pion mass using a low-density target of light atoms

    CERN Document Server

    Trassinelli, M; Borchert, G; Dax, A; Egger, J -P; Gotta, D; Hennebach, M; Indelicato, P; Liu, Y -W; Manil, B; Nelms, N; Simons, L M; Wells, A

    2016-01-01

    We present a new evaluation of the negatively charged pion mass based on the simultaneous spec-troscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N 2 /O 2 mixture at 1.4 bar. We present the experimental setup and the methods for deriving the pion mass value from the spatial separation from the 5g -- 4 f $\\pi$N transition line and the 5g -- 4 f $\\mu$O transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  11. Measurement of the charged pion mass using a low-density target of light atoms

    Directory of Open Access Journals (Sweden)

    Trassinelli M.

    2016-01-01

    Full Text Available We present a new evaluation of the negatively charged pion mass based on the simultaneous spectroscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N2/O2 mixture at 1.4 bar. We present the experimental set-up and the methods for deriving the pion mass value from the spatial separation from the 5g − 4f πN transition line and the 5g − 4f μO transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  12. Pion correlations as a function of atomic mass in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Chacon, A.D.

    1989-11-26

    The method of two pion interferometry was used to obtain source-size and lifetime parameters for the pions produced in heavy ion collisions. The systems used were 1.70 {center dot} A GeV {sup 56}Fe + Fe, 1.82 {center dot} A GeV {sup 40}Ar + KCl and 1.54 {center dot} A GeV {sup 93}Nb + Nb, allowing for a search for dependences on the atomic number. Two acceptances (centered, in the lab., at {approximately} 0{degrees} and 45{degrees}) were used for each system, allowing a search for dependences on the viewing angle. The correlation functions were calculated by comparing the data samples to background (or reference) samples made using the method of event mixing, where pions from different events are combined to produce a data sample in which the Bose-Einstein correlation effect is absent. The effect of the correlation function on the background samples is calculated, and a method for weighting the events to remove the residual correlation effect is presented. The effect of the spectrometer design on the measured correlation functions is discussed, as are methods for correcting for these effects during the data analysis. 58 refs., 39 figs., 18 tabs.

  13. Effects of mass operator energy dependence in atomic nuclei. Quasiparticle lagrangian versus quasiparticle hamiltonian

    Energy Technology Data Exchange (ETDEWEB)

    Khodel, V.A.; Saperstein, E.E.; Zverev, M.V.

    1987-04-13

    Different effects of the mass operator energy dependence are discussed. They are calculated within the framework of the Hartree-Fock (HF) method with effective forces as RPA corrections to the HF ground state. In the quasiparticle Lagrange method (QLM) they arise naturally and are taken into account in the self-consistent procedure itself. Approaches with the quasiparticle lagrangian and quasiparticle hamiltonian are compared. It is shown that the QLM can also be formulated with the help of the hamiltonian, but a simple lagrangian corresponds to a very complicated hamiltonian. Arguments in favour of the simple lagrangian are presented.

  14. Effect of substrate thickness on ejection of phenylalanine molecules adsorbed on free-standing graphene bombarded by 10 keV C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Golunski, M. [Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Krakow (Poland); Verkhoturov, S.V.; Verkhoturov, D.S.; Schweikert, E.A. [Department of Chemistry, Texas A& M University, College Station, TX 77840 (United States); Postawa, Z., E-mail: zbigniew.postawa@uj.edu.pl [Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Krakow (Poland)

    2017-02-15

    Highlights: • Substrate thickness has a prominent effect on the molecular ejection mechanism. • Collisions with projectile atoms leads to molecular ejection at thin substrates. • Interactions with deforming graphene sheet ejects molecules from thicker substrates. • Probability of fragmentation process decreases with the graphene substrate thickness. - Abstract: Molecular dynamics computer simulations have been employed to investigate the effect of substrate thickness on the ejection mechanism of phenylalanine molecules deposited on free-standing graphene. The system is bombarded from the graphene side by 10 keV C{sub 60} projectiles at normal incidence and the ejected particles are collected both in transmission and reflection directions. It has been found that the ejection mechanism depends on the substrate thickness. At thin substrates mostly organic fragments are ejected by direct collisions between projectile atoms and adsorbed molecules. At thicker substrates interaction between deforming topmost graphene sheet and adsorbed molecules becomes more important. As this process is gentle and directionally correlated, it leads predominantly to ejection of intact molecules. The implications of the results to a novel analytical approach in Secondary Ion Mass Spectrometry based on ultrathin free-standing graphene substrates and a transmission geometry are discussed.

  15. Combined use of atomic force microscopy, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry for cell surface analysis.

    Science.gov (United States)

    Dague, Etienne; Delcorte, Arnaud; Latgé, Jean-Paul; Dufrêne, Yves F

    2008-04-01

    Understanding the surface properties of microbial cells is a major challenge of current microbiological research and a key to efficiently exploit them in biotechnology. Here, we used three advanced surface analysis techniques with different sensitivity, probing depth, and lateral resolution, that is, in situ atomic force microscopy, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry, to gain insight into the surface properties of the conidia of the human fungal pathogen Aspergillus fumigatus. We show that the native ultrastructure, surface protein and polysaccharide concentrations, and amino acid composition of three mutants affected in hydrophobin production are markedly different from those of the wild-type, thereby providing novel insight into the cell wall architecture of A. fumigatus. The results demonstrate the power of using multiple complementary techniques for probing microbial cell surfaces.

  16. Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates

    Science.gov (United States)

    Ladhaf, Bibifatima M.; Pawar, Pravina P.

    2015-04-01

    We measured here the mass attenuation coefficients (μ/ρ) of carbohydrates, Esculine (C15H16O9), Sucrose (C12H22O11), Sorbitol (C6H14O6), D-Galactose (C6H12O6), Inositol (C6H12O6), D-Xylose (C5H10O5) covering the energy range from 122 keV up to 1330 keV photon energies by using gamma ray transmission method in a narrow beam good geometry set-up. The gamma-rays were detected using NaI(Tl) scintillation detection system with a resolution of 8.2% at 662 keV. The attenuation coefficient data were then used to obtain the total attenuation cross-section (σtot), molar extinction coefficients (ε), mass-energy absorption coefficients (μen/ρ) and effective (average) atomic energy-absorption cross section (σa,en) of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

  17. Determination of total mass attenuation coefficients, effective atomic numbers and electron densities for different shielding materials used in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Almeida J, A. T. [FUNDACENTRO, Centro Regional de Minas Gerais, Brazilian Institute for Safety and Health at Work, Belo Horizonte, 30180-100 Minas Gerais (Brazil); Nogueira, M. S. [Center of Development of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Santos, M. A. P., E-mail: mnogue@cdtn.br [Regional Center for Nuclear Science / CNEN, 50.740-540 Recife, Pernambuco (Brazil)

    2015-10-15

    Full text: In this paper, the interaction of X-rays with some shielding materials has been studied for materials containing different amounts of barite and aggregates. The total mass attenuation coefficient (μ{sub t}) for three shielding materials has been calculated by using WinXCOM program in the energy range from RQR qualities (RQR-4, RQR-6, RQR-9, and RQR-10). They were: cream barite (density 2.99 g/cm{sup 3} collected in the State of Sao Paulo), purple barite (density 2.95 g/cm{sup 3} collected in the State of Bahia) and white barite (density 3.10 g/cm{sup 3} collected in the State of Paraiba). The chemical analysis was carried out by an X-ray fluorescence spectrometer model EDX-720, through dispersive energy. The six elements of the higher concentration found in the sample and analyzed by Spectrophotometry of Energy Dispersive X-ray for the samples were Ba(60.9% - white barite), Ca(17,92% - cream barite), Ce(3,60% - white barite), Fe(17,16% - purple barite), S(12,11% - white barite) and Si(29,61% - purple barite). Also, the effective atomic number (Z{sub eff}) and the effective electron density (N{sub eff}) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined. (Author)

  18. Mass the quest to understand matter from Greek atoms to quantum fields

    CERN Document Server

    Baggott, Jim

    2017-01-01

    Everything around us is made of 'stuff', from planets, to books, to our own bodies. Whatever it is, we call it matter or material substance. It is solid; it has mass. But what is matter, exactly? We are taught in school that matter is not continuous, but discrete. As a few of the philosophers of ancient Greece once speculated, nearly two and a half thousand years ago, matter comes in 'lumps', and science has relentlessly peeled away successive layers of matter to reveal its ultimate constituents. Surely, we can't keep doing this indefinitely. We imagine that we should eventually run up against some kind of ultimately fundamental, indivisible type of stuff, the building blocks from which everything in the Universe is made. The English physicist Paul Dirac called this 'the dream of philosophers'. But science has discovered that the foundations of our Universe are not as solid or as certain and dependable as we might have once imagined. They are instead built from ghosts and phantoms, of a peculiar quantum kind....

  19. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reininger, Charlotte; Woodfield, Kellie [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States); Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M. [Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA 30332 (United States); Farnsworth, Paul B., E-mail: paul_farnsworth@byu.edu [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States)

    2014-10-01

    The absolute number densities of helium atoms in the 2s {sup 3}S{sub 1} metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 10{sup 12} cm{sup −3} and 0.011 × 10{sup 12} cm{sup −3}, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 10{sup 12} cm{sup −3} and 0.97 × 10{sup 12} cm{sup −3} were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges. - Highlights: • We determine He metastable number densities for four plasma types • The highest number densities were observed in a dielectric barrier discharge • No helium metastable atoms were observed downstream from the exits of glow discharges.

  20. Resonant laser ablation of metals detected by atomic emission in a microwave plasma and by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Cleveland, Danielle; Stchur, Peter; Hou, Xiandeng; Yang, Karl X; Zhou, Jack; Michel, Robert G

    2005-12-01

    It has been shown that an increase in sensitivity and selectivity of detection of an analyte can be achieved by tuning the ablation laser wavelength to match that of a resonant gas-phase transition of that analyte. This has been termed resonant laser ablation (RLA). For a pulsed tunable nanosecond laser, the data presented here illustrate the resonant enhancement effect in pure copper and aluminum samples, chromium oxide thin films, and for trace molybdenum in stainless steel samples, and indicate two main characteristics of the RLA phenomenon. The first is that there is an increase in the number of atoms ablated from the surface. The second is that the bandwidth of the wavelength dependence of the ablation is on the order of 1 nm. The effect was found to be virtually identical whether the atoms were detected by use of a microwave-induced plasma with atomic emission detection, by an inductively coupled plasma with mass spectrometric detection, or by observation of the number of laser pulses required to penetrate through thin films. The data indicate that a distinct ablation laser wavelength dependence exists, probably initiated via resonant radiation trapping, and accompanied by collisional broadening. Desorption contributions through radiation trapping are substantiated by changes in crater morphology as a function of wavelength and by the relatively broad linewidth of the ablation laser wavelength scans, compared to gas-phase excitation spectra. Also, other experiments with thin films demonstrate the existence of a distinct laser-material interaction and suggest that a combination of desorption induced by electronic transition (DIET) with resonant radiation trapping could assist in the enhancement of desorption yields. These results were obtained by a detailed inspection of the effect of the wavelength of the ablation laser over a narrow range of energy densities that lie between the threshold of laser-induced desorption of species and the usual analytical

  1. Protons from the alpha-particle bombardment of 31P

    NARCIS (Netherlands)

    Kuperus, J.

    Resonances in the yield of ground-state protons from alpha-particle bombardment of 31P were investigated in the energy range Eα = 1.7 − 3.3 MeV. Fourteen resonances were observed, none of which was known before. Resonance energies and strengths are presented. Angular distribution measurements lead

  2. Protons from the alpha-particle bombardment of 23Na

    NARCIS (Netherlands)

    Kuperus, J.

    1964-01-01

    Resonances in the yield of ground-state protons from alpha-particle bombardment of 23Na were investigated in the energy range Eα = 1.0 – 3.3 MeV. At least thirty-eight resonances were observed. Resonance energies and strengths are presented. At nine resonances angular distribution measurements lead

  3. Comparison of Se and Te clusters produced by ion bombardment

    Science.gov (United States)

    Trzyna, Małgorzata

    2017-01-01

    Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS). It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to 1300 m/z. Local maxima or minima (magic numbers) are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  4. Comparison of Se and Te clusters produced by ion bombardment

    Directory of Open Access Journals (Sweden)

    Trzyna Małgorzata

    2017-01-01

    Full Text Available Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS. It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to ~ 1300 m/z. Local maxima or minima (magic numbers are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  5. Combination of atomic force microscopy and mass spectrometry for the detection of target protein in the serum samples of children with autism spectrum disorders

    Science.gov (United States)

    Kaysheva, A. L.; Pleshakova, T. O.; Kopylov, A. T.; Shumov, I. D.; Iourov, I. Y.; Vorsanova, S. G.; Yurov, Y. B.; Ziborov, V. S.; Archakov, A. I.; Ivanov, Y. D.

    2017-10-01

    Possibility of detection of target proteins associated with development of autistic disorders in children with use of combined atomic force microscopy and mass spectrometry (AFM/MS) method is demonstrated. The proposed method is based on the combination of affine enrichment of proteins from biological samples and visualization of these proteins by AFM and MS analysis with quantitative detection of target proteins.

  6. Fundamentals for magnetic patterning by ion bombardment of exchange bias layer systems

    Science.gov (United States)

    Ehresmann, A.; Engel, D.; Weis, T.; Schindler, A.; Junk, D.; Schmalhorst, J.; Höink, V.; Sacher, M. D.; Reiss, G.

    2006-01-01

    In the present paper we investigate whether the ion bombardment induced magnetic modifications in exchange biased bilayers are stable in time, whether the direction of the exchange bias can be set to any arbitrary (in-plane) direction by the ion bombardment and whether the exchange bias field can be changed in successive bombardment steps. These three fundamental characteristics are prerequisites for ion bombardment used for an efficient, practical, and stable magnetic patterning of exchange biased layer systems.

  7. Highly sensitive protein detection by combination of atomic force microscopy fishing with charge generation and mass spectrometry analysis.

    Science.gov (United States)

    Ivanov, Yuri D; Pleshakova, Tatyana; Malsagova, Krystina; Kozlov, Andrey; Kaysheva, Anna; Kopylov, Arthur; Izotov, Alexander; Andreeva, Elena; Kanashenko, Sergey; Usanov, Sergey; Archakov, Alexander

    2014-10-01

    An approach combining atomic force microscopy (AFM) fishing and mass spectrometry (MS) analysis to detect proteins at ultra-low concentrations is proposed. Fishing out protein molecules onto a highly oriented pyrolytic graphite surface coated with polytetrafluoroethylene film was carried out with and without application of an external electric field. After that they were visualized by AFM and identified by MS. It was found that injection of solution leads to charge generation in the solution, and an electric potential within the measuring cell is induced. It was demonstrated that without an external electric field in the rapid injection input of diluted protein solution the fishing is efficient, as opposed to slow fluid input. The high sensitivity of this method was demonstrated by detection of human serum albumin and human cytochrome b5 in 10(-17) -10(-18) m water solutions. It was shown that an external negative voltage applied to highly oriented pyrolytic graphite hinders the protein fishing. The efficiency of fishing with an external positive voltage was similar to that obtained without applying any voltage. © 2014 FEBS.

  8. Seduction of Finding Universality in Sputtering Yields Due to Cluster Bombardment of Solids.

    Science.gov (United States)

    Paruch, Robert J; Postawa, Zbigniew; Garrison, Barbara J

    2015-09-15

    Universal descriptions are appealing because they simplify the description of different (but similar) physical systems, allow the determination of general properties, and have practical applications. Recently, the concept of universality has been applied to the dependence of the sputtering (ejection) yield due to energetic cluster bombardment versus the energy of the incident cluster. It was observed that the spread in data points can be reduced if the yield Y and initial projectile cluster kinetic energy E are expressed in quantities scaled by the number of cluster atoms n, that is, Y/n versus E/n. The convergence of the data points is, however, not perfect, especially when the results for molecular and atomic solids are compared. In addition, the physics underlying the apparent universal dependence in not fully understood. For the study presented in this Account, we performed molecular dynamics simulations of Arn cluster bombardment of molecular (benzene, octane, and β-carotene) and atomic (Ag) solids in order to address the physical basis of the apparent universal dependence. We have demonstrated that the convergence of the data points between molecular and atomic solids can be improved if the binding energy of the solid U0 is included and the dependence is presented as Y/(E/U0) versus (E/U0)/n. As a material property, the quantity U0 is defined per the basic unit of material, which is an atom for atomic solids and a molecule for molecular solids. Analogously, the quantity Y is given in atoms and molecules, respectively. The simulations show that, for almost 3 orders of magnitude variation of (E/U0)/n, there are obvious similarities in the ejection mechanisms between the molecular and atomic solids, thus supporting the concept of universality. For large (E/U0)/n values, the mechanism of ejection is the fluid flow from a cone-shaped volume. This regime of (E/U0)/n is generally accessed experimentally by clusters with hundreds of atoms and results in the largest

  9. The New Element Curium (Atomic Number 96)

    Science.gov (United States)

    Seaborg, G. T.; James, R. A.; Ghiorso, A.

    1948-01-01

    Two isotopes of the element with atomic number 96 have been produced by the helium-ion bombardment of plutonium. The name curium, symbol Cm, is proposed for element 96. The chemical experiments indicate that the most stable oxidation state of curium is the III state.

  10. Determination of Zn-citrate in human milk by CIM monolithic chromatography with atomic and mass spectrometry detection.

    Science.gov (United States)

    Milačič, Radmila; Ajlec, Dejan; Zuliani, Tea; Žigon, Dušan; Ščančar, Janez

    2012-11-15

    In human milk zinc (Zn) is bound to proteins and low molecular mass (LMM) ligands. Numerous investigations demonstrated that Zn bioavailability in human milk is for infant much higher than in cow's milk. It was presumed that in the LMM human milk fraction highly bioavailable Zn-citrate prevails. However, literature data are controversial regarding the amount of Zn-citrate in human milk since analytical procedures reported were not quantitative. So, complex investigation was carried out to develop analytical method for quantitative determination of this biologically important molecule. Studies were performed within the pH range 5-7 by the use of synthetic solutions of Zn-citrate prepared in HEPES, MOPS and MES buffers. Zn-citrate was separated on weak anion-exchange convective interaction media (CIM) diethylaminoethyl (DEAE) monolithic chromatographic column using NH(4)NO(3) as an eluent. Separated Zn species were determined by flame atomic absorption spectrometry (FAAS) or inductively coupled plasma mass spectrometry (ICP-MS). Quantitative separation of Zn-citrate complexes ([Zn(Cit)](-) and [Zn(Cit)(2)](4-); column recoveries 94-102%) and good repeatability and reproducibility of results with relative standard deviation (RSD±3.0%) were obtained. In fractions under the chromatographic peaks Zn-binding ligand was identified by electrospray ionization tandem mass spectrometry (ESI-MS-MS). Limits of detection (LOD) for determination of Zn-citrate species by CIM DEAE-FAAS and CIM DEAE-ICP-MS were 0.01 μg Zn mL(-1) and 0.0005 μg Zn mL(-1), respectively. Both techniques were sensitive enough for quantification of Zn-citrate in human milk. Results demonstrated that about 23% of total Zn was present in the LMM milk fraction and that LMM-Zn corresponded to Zn-citrate. The developed speciation method represents a reliable analytical tool for investigation of the percentage and the amount of Zn-citrate in human milk. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry. Progress report, January 1, 1990--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Montaser, A.

    1992-09-01

    New high temperature plasmas and new sample introduction systems are explored for rapid elemental and isotopic analysis of gases, solutions, and solids using mass spectrometry and atomic emission spectrometry. Emphasis was placed on atmospheric pressure He inductively coupled plasmas (ICP) suitable for atomization, excitation, and ionization of elements; simulation and computer modeling of plasma sources with potential for use in spectrochemical analysis; spectroscopic imaging and diagnostic studies of high temperature plasmas, particularly He ICP discharges; and development of new, low-cost sample introduction systems, and examination of techniques for probing the aerosols over a wide range. Refs., 14 figs. (DLC)

  12. The in situ spatial arrangement of the influenza A virus matrix protein M1 assessed by tritium bombardment

    Science.gov (United States)

    Shishkov, Alexander V.; Goldanskii, Vitalii I.; Baratova, Ludmila A.; Fedorova, Natalia V.; Ksenofontov, Alexander L.; Zhirnov, Oleg P.; Galkin, Alexander V.

    1999-01-01

    Intact influenza A virions were bombarded with thermally activated tritium atoms, and the intramolecular distribution of the label in the matrix protein M1 was analyzed to determine the in situ accessibility of its tryptic fragments. These data were combined with the previously reported x-ray crystal structure of the M1 fragment 2–158 [Sha, B. & Luo, M. (1997) Nat. Struct. Biol. 4, 239–244] and the predicted topology of the C domain (159–252) to propose a model of M1 arrangement in the virus particle. PMID:10393906

  13. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  14. Surface chemical reactions induced on pyrite by ion bombardment

    Science.gov (United States)

    Ruano, Gustavo; Pomiro, Fernando; Ferrón, Julio

    2018-01-01

    Through X-ray photoemission spectroscopy (XPS), we studied the chemical changes induced in a natural crystal of pyrite (FeS2) upon exposure to 4.5 keV He+ beam. We found an important reducing effect induced by ion bombardment leading to the production of iron embedded in the pyrite matrix. Through a combination of the usual Doniach-Sunjic treatment and Factor Analysis of XPS yields, we were able of analyzing the full Fe 2p XPS signal. We could in this way distinguish Fe compounds with the same binding energy for the Fe 2p3/2 yield. Our results show that He+ bombardment disrupts the ionic environment producing S2-2 and S0, Fe2+ and Fe3+ ions, and the reduction to metallic iron. The remaining pyrite matrix does not passivate the embedded iron structures, which are readily oxidized under air exposure. The oxide formed resembled that of magnetite from the XPS point of view. Further He+ bombardment proved to be efficient to reduce the iron oxide back to iron again.

  15. Low energy electron bombardment induced surface contamination of Ru mirrors

    Science.gov (United States)

    Al-Ajlony, A.; Kanjilal, A.; Catalfano, M.; Harilal, S. S.; Hassanein, A.; Rice, B.

    2012-03-01

    The impact of secondary electrons induced contamination of the Ru surface was investigated. Mirror-like Ru sample was bombarded with low energy (100 eV) electrons and the change in surface chemistry was investigated using X-ray photoelectron spectroscopy (XPS).Along with XPS studies the corresponding effect on in-situ EUV reflectivity was examined by exposing the Ru surface to photons at a wavelength of 13.5 nm in an ultrahigh vacuum chamber. Detailed XPS analyses showed a sudden increase in carbon concentrations on the Ru surface in the first 60 min, followed by a slow but linear growth in carbon concentration. In parallel, a noticeable decrease in water content was observed during the time of electrons irradiation along with slight oxidation of pure Ru surface. All chemical changes were discussed in terms of the electrons bombardment mediated dissociation of water and hydrocarbon molecules. A time dependent EUV reflectivity measurements show insignificant change in reflectivity up to 510 min of electrons bombardment. The impact of water molecules on the Ru surface and the accumulation of carbon through dissociation of residual hydrocarbons is discussed in details.

  16. The Mass Attenuation Coefficients, Electronic, Atomic, and Molecular Cross Sections, Effective Atomic Numbers, and Electron Densities for Compounds of Some Biomedically Important Elements at 59.5 keV

    Directory of Open Access Journals (Sweden)

    Burcu Akça

    2014-01-01

    Full Text Available The mass attenuation coefficients for compounds of biomedically important some elements (Na, Mg, Al, Ca, and Fe have been measured by using an extremely narrow collimated-beam transmission method in the energy 59.5 keV. Total electronic, atomic, and molecular cross sections, effective atomic numbers, and electron densities have been obtained by using these results. Gamma-rays of 241Am passed through compounds have been detected by a high-resolution Si(Li detector and by using energy dispersive X-ray fluorescence spectrometer (EDXRF. Obtained results have been compared with theoretically calculated values of WinXCom and FFAST. The relative difference between the experimental and theoretical values are −9.4% to +11.9% with WinXCom and −11.8% to +11.7% FFAST. Results have been presented and discussed in this paper.

  17. Photon and secondary ion emission from keV cluster bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, R.G. [Texas A& M Univ., College Station, TX (United States)

    1994-12-31

    CsI clusters (Cs{sub n}I{sup {minus}}{sub n+1} n = 0 to 4) in the keV energy range (15 to 45 keV) have been used to bombard CsI targets in time-of-flight mass spectrometry experiments to study the relationships between secondary ion and photon emissions. Single ions and photons were detected simultaneously from the impact of single projectiles. The secondary ion yields from the polyatomic projectiles are proportional to the projectile momentum. The photon yields are roughly proportional to both the electronic and the nuclear stopping powers. The photon emission from the bulk of the CsI targets is attributed to excitonic processes.

  18. Carbon monoxide production in low energy oxygen ion bombardment of pyrolytic graphite and Kapton surfaces

    Science.gov (United States)

    Horton, C. C.; Eck, T. G.; Hoffman, R. W.

    1986-01-01

    The results of an investigtion of the interaction of low energy oxygen ions with pyrolytic graphite and Kapton surface are reported. CO molecules emitted from the surface as a result of the ion bombardment were detected by a mass spectrometer. Because the ion-induced signals were small compared to that arising from the CO background pressure in the vacuum system, the ion beam was modulated and the modulated component of the CO signal measured with a lock-in amplifier. The quantum yield (CO molecules emitted per incident oxygen ion) for graphite rose from 1.9 at 4.5 eV ion energy to 6.6 at 465 eV. Comparable yields were obtained for Kapton. The large size of the yields suggests contributions to the reaction process from the background O2 molecules in the vacuum system.

  19. Fracture toughness and leaching behavior of ion bombarded waste glasses

    Science.gov (United States)

    Matzke, Hj.; Linker, G.

    1984-02-01

    Fracture toughness Klc and fracture surface energy γ were measured on borosilicate waste glasses containing simulated fission products produced in the Institut für Nukleare Entsorgung, KFK. The Hertzian indentation technique with spherical indenters was shown to be a very powerful means with which to study mechanical and fracture properties of small highly radioactive samples. It was tested with Pu-ceramics as well as with Cm-doped glass ceramics. Radiation damage was produced by ion bombardment with Pb or Xe ions of energies up to 300 keV or with He 2+-ions (α-particles) of the cyclotron (KFK) with energies up to 77 MeV. The glasses were used either as-received or else following high-temperature, high-pressure autoclave leaching. The as-bombarded and the leached glasses were analyzed for surface composition and changes by Rutherford backscattering, RBS, with He-ions. In many cases, radiation damage caused an increase in fracture toughness, a very beneficial effect. The leached glasses that were investigated contained surface layers with thicknesses of up to ˜2 μm. RBS showed these layers to be similar in composition to thick layers analyzed by electron microprobe analysis (empa). There was no drastic influence of ion bombardment on the composition or thickness of these layers. The layers themselves caused changes of about ± 10% in the apparent fracture toughness, possibly by absorbing part of the applied energy by plastic deformation or by preventing pre-existing flaws from initiating crack formation.

  20. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  1. Switchable resonant x-ray Bragg scattering on a magnetic grating patterned by ion bombardment

    Science.gov (United States)

    Höink, V.; Sacher, M. D.; Schmalhorst, J.; Reiss, G.; Engel, D.; Weis, T.; Ehresmann, A.

    2006-09-01

    A local manipulation of the exchange bias coupling between antiferromagnetic and ferromagnetic layers by ion bombardment induced magnetic patterning enables a patterning of the magnetization direction of the ferromagnetic layer without considerable structural changes. We show that a magnetic line grating with alternating antiparallel orientations of the magnetization of the ferromagnetic layer acts as a magnetically switchable reflective grating for soft x-ray radiation. A common rotational direction of the magnetization at all boundaries between bombarded and not bombarded lines is shown by magnetic force microscopy measurements. Scattering at the edges of the bombarded lines might be responsible for the observed interference pattern.

  2. Fundamentals for magnetic patterning by ion bombardment of exchange bias layer systems

    Energy Technology Data Exchange (ETDEWEB)

    Ehresmann, A.; Engel, D.; Weis, T. [Institute of Physics and Centre for Interdisciplinary Nanostructure Science and Technology (CINSaT), Kassel University, Heinrich-Plett-Str. 40, 34132 Kassel (Germany); Schindler, A. [Institut fuer Festkoerperforschung, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Junk, D. [Technische Physik, Universitaet des Saarlandes, P.O. Box 151150, 66041 Saarbruecken (Germany); Schmalhorst, J.; Hoeink, V.; Sacher, M.D.; Reiss, G. [Faculty of Physics, Bielefeld University, P.O. Box 100131, 33501 Bielefeld (Germany)

    2006-01-01

    In the present paper we investigate whether the ion bombardment induced magnetic modifications in exchange biased bilayers are stable in time, whether the direction of the exchange bias can be set to any arbitrary (in-plane) direction by the ion bombardment and whether the exchange bias field can be changed in successive bombardment steps. These three fundamental characteristics are prerequisites for ion bombardment used for an efficient, practical, and stable magnetic patterning of exchange biased layer systems. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Postannealing of magnetic tunnel junctions with ion-bombardment-modified exchange bias

    Science.gov (United States)

    Höink, V.; Sacher, M. D.; Schmalhorst, J.; Reiss, G.; Engel, D.; Junk, D.; Ehresmann, A.

    2005-04-01

    The influence of a postannealing procedure on the transport properties of magnetic tunnel junctions with ion-bombardment-manipulated exchange bias is investigated. The controlled manipulation of the direction of the exchange bias field in magnetic tunnel junctions by He ion bombardment usually is accompanied by a reduction of the tunneling magnetoresistance and an increase in the resistance. Here, we demonstrate that it is possible to reduce these negative effects of the ion bombardment considerably by postannealing without a magnetic field. For optimized combinations of ion dose and postannealing temperature, the tunneling magnetoresistance recovers completely (>50% resistance change) while the exchange bias direction set by the ion bombardement is preserved.

  4. Assessment of homogeneity and minimum sample mass for cadmium analysis in powdered certified reference materials and real rice samples by solid sampling electrothermal vaporization atomic fluorescence spectrometry.

    Science.gov (United States)

    Mao, Xuefei; Liu, Jixin; Huang, Yatao; Feng, Li; Zhang, Lihua; Tang, Xiaoyan; Zhou, Jian; Qian, Yongzhong; Wang, Min

    2013-01-30

    To optimize analytical quality controls of solid sampling electrothermal vaporization atomic fluorescence spectrometry (SS-ETV-AFS), the homogeneity (H(E)) of rice samples and their minimum sample mass (M) for cadmium analysis were evaluated using three certified reference materials (CRMs) and real rice samples. The effects of different grinding degrees (particle sizes 1 mm) on H(E) and M of real rice samples were also investigated. The calculated M values of three CRMs by the Pauwels equation were 2.19, 19.76, and 3.79 mg. The well-ground real rice samples (particle size method were compared with the results by microwave digestion graphite furnace atomic absorption spectrometry with a 0.5 g sample mass. There was no significant difference between these two methods, which meant that SS-ETV-AFS could be used to accurately detect Cd in rice with several milligrams of samples instead of the certified value (200 mg) or the recommended mass (200-500 mg) of the methods of the Association of Official Analytical Chemists.

  5. Klaus Blaum, of GSI Darmstadt and project leader of the ISOLTRAP experiment at CERN, will receive the 2004 Gustav-Hertz-Prize for his outstanding work on the mass determination of unstable atomic nuclei

    CERN Multimedia

    2004-01-01

    Klaus Blaum, of GSI Darmstadt and project leader of the ISOLTRAP experiment at CERN, will receive the 2004 Gustav-Hertz-Prize for his outstanding work on the mass determination of unstable atomic nuclei

  6. Implementation of suitable flow injection/sequential-sample separation/preconcentration schemes for determination of trace metal concentrations using detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Wang, Jianhua

    2002-01-01

    Various preconditioning procedures encomprising appropriate separation/preconcentration schemes in order to obtain optimal sensitivity and selectivity characteristics when using electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS...

  7. Fe embedded in ice: The impacts of sublimation and energetic particle bombardment

    Science.gov (United States)

    Frankland, Victoria L.; Plane, John M. C.

    2015-05-01

    Icy particles containing a variety of Fe compounds are present in the upper atmospheres of planets such as the Earth and Saturn. In order to explore the role of ice sublimation and energetic ion bombardment in releasing Fe species into the gas phase, Fe-dosed ice films were prepared under UHV conditions in the laboratory. Temperature-programmed desorption studies of Fe/H2O films revealed that no Fe atoms or Fe-containing species co-desorbed along with the H2O molecules. This implies that when noctilucent ice cloud particles sublimate in the terrestrial mesosphere, the metallic species embedded in them will coalesce to form residual particles. Sputtering of the Fe-ice films by energetic Ar+ ions was shown to be an efficient mechanism for releasing Fe into the gas phase, with a yield of 0.08 (Ar+ energy=600 eV). Extrapolating with a semi-empirical sputtering model to the conditions of a proton aurora indicates that sputtering by energetic protons (>100 keV) should also be efficient. However, the proton flux in even an intense aurora will be too low for the resulting injection of Fe species into the gas phase to compete with that from meteoric ablation. In contrast, sputtering of the icy particles in the main rings of Saturn by energetic O+ ions may be the source of recently observed Fe+ in the Saturnian magnetosphere. Electron sputtering (9.5 keV) produced no detectable Fe atoms or Fe-containing species. Finally, it was observed that Fe(OH)2 was produced when Fe was dosed onto an ice film at 140 K (but not at 95 K). Electronic structure theory shows that the reaction which forms this hydroxide from adsorbed Fe has a large barrier of about 0.7 eV, from which we conclude that the reaction requires both translationally hot Fe atoms and mobile H2O molecules on the ice surface.

  8. Evidence Supporting an Early as Well as Late Heavy Bombardment on the Moon

    Science.gov (United States)

    Frey, Herbert

    2015-01-01

    Evidence supporting an intense early bombardment on the Moon in addition to the traditional Late Heavy Bombardment at approx. 4 BY ago include the distribution of N(50) Crater Retention Ages (CRAs) for candidate basins, a variety of absolute age scenarios for both a "young" and an "old" Nectaris age, and the decreasing contrasts in both topographic relief and Bouguer gravity with increasing CRA.

  9. Diamond-like carbon layers modified by ion bombardment during growth and researched by Resonant Ultrasound Spectroscopy

    Science.gov (United States)

    Kocourek, Tomáš; Jelínek, Miroslav; Písařík, Petr; Remsa, Jan; Janovská, Michaela; Landa, Michal; Zemek, Josef; Havránek, Vladimír

    2017-09-01

    Biocompatible Diamond-Like Carbon (DLC) films were prepared by Pulsed Laser Deposition technique using the laser energy density of 10 J cm-2 on the graphite target. The surface of the grown film was modified during the deposition by bombardment with argon, xenon, nitrogen or oxygen ions. The ion energy (up to 150 eV) was changed by gun voltage and by ionic current. The films with high and low diamond/graphite content were prepared. Physical and mechanical properties of biocompatible DLC thin layers prepared by hybrid laser technology were studied. The composition of layers and the content trace elements were determined by the methods of Rutherford Backscattering Spectrometry and Particle Induced X-ray Emission. The content of sp2 and sp3 bonds was measured using X-ray Photoelectron Spectroscopy. For different energy of argon and oxygen ions the maximum of sp3 bonds content was found (83.63% of sp3 bonds for argon ions). All films were smooth, which was confirmed by profilometry and Atomic Force Microscopy measurements. Maximum roughness Ra and RMS was did not exceed 1 nm. The Younǵs and shear moduli were studied by Resonant Ultrasound Spectroscopy. The Young's Modulus attained the value of 601 GPa and the shear Modulus attained the value of 253 GPa at the energy of 30 eV of Ar ions. The influence of ion bombardment on DLC film properties is discussed.

  10. Atomic tritium as a surface nanoprobe in a structural investigation of molecular assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Badun, G.A.; Lukashina, E.V.; Batuk, O.N.; Ksenofontov, A.L.; Fedoseev, V.M

    2003-12-15

    Possibilities of atomic tritium application as surface nanoprobe for structural investigations of adsorption layers on the liquid-air interface have been demonstrated. Frozen aqueous solutions of a series of amino acids and their mixtures and one well-known surface-active substance (cetyltrimethylammonium bromide, CTAB) were exposed to bombardment by tritium atoms generated on hot tungsten wire in a special vacuum device. This procedure resulted in substitution of hydrogen atoms by radioactive tritium in the thin surface layer of investigated samples. Curves of radioactivity changes depending on bombardment time and solution concentration for applied compounds were obtained and analyzed.

  11. Stable transformation of the oomycete, Phytophthora infestans, using microprojectile bombardment

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Judelson, Howard S.

    2003-01-01

    Germinated asexual sporangia, zoospores, and mycelia of Phytophthora infestans were transformed to G418-resistance by microprojectile bombardment. After optimization, an average of 14 transformants/shot were obtained, using 10(6) germinated sporangia and gold particles coated with 1 microg...... of vector. Transformants displayed tandem or simple insertions of vector sequences within chromosomes. Most primary transformants were heterokaryons of transformed and wild-type nuclei, a state which generally persisted for generations, even with G418 selection. Transgenic homokaryons were easily obtained...... from primary transformants through G418 selection of zoospores. To facilitate the optimization of transformation, experiments were performed using a vector containing neomycin phosphotransferase (npt) and beta-glucuronidase (GUS) genes fused to oomycete transcriptional regulatory sequences. To indicate...

  12. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  13. Characterization of CdZnTe after argon ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Bensalah, H., E-mail: hakima.bensalah@uam.es [Departamento de Fisica de Materiales, Laboratorio de Crecimiento de Cristales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Hortelano, V. [GdS-Optronlab Group, Departamento Fisica Materia Condensada, Universidad de Valladolid, Edificio I-D, Paseo de Belen 1, 47011 Valladolid (Spain); Plaza, J.L. [Departamento de Fisica de Materiales, Laboratorio de Crecimiento de Cristales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Martinez, O. [GdS-Optronlab Group, Departamento Fisica Materia Condensada, Universidad de Valladolid, Edificio I-D, Paseo de Belen 1, 47011 Valladolid (Spain); Crocco, J.; Zheng, Q.; Carcelen, V.; Dieguez, E. [Departamento de Fisica de Materiales, Laboratorio de Crecimiento de Cristales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2012-12-05

    Highlights: Black-Right-Pointing-Pointer After argon irradiation using low fluence, the defects on surface were removed. Black-Right-Pointing-Pointer The PL intensity increases after irradiation. This increase should be related to the improved quality of the CdZnTe surfaces. Black-Right-Pointing-Pointer Irradiation process lead to an elimination of Te precipitates from the surfaces of the CdZnTe samples. - Abstract: The objective of this work is to analyze the effects of argon ion irradiation process on the structure and distribution of Te inclusions in Cd{sub 1-x}Zn{sub x}Te crystals. The samples were treated with different ion fluences ranging from 2 to 8 Multiplication-Sign 10{sup 17} cm{sup -2}. The state of the samples before and after irradiation were studied by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Cathodoluminescence, Photoluminescence, and micro-Raman spectroscopy. The effect of the irradiation on the surface of the samples was clearly observed by SEM or AFM. Even for small fluences a removal of polishing scratches on the sample surfaces was observed. Likely correlated to this effect, an important enhancement in the luminescence intensity of the irradiated samples was observed. An aggregation effect of the Te inclusions seems to occur due to the Ar bombardment, which are also eliminated from the surfaces for the highest ion fluences used.

  14. Electron-bombarded 〈110〉-oriented tungsten tips for stable tunneling electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, T. K.; Abe, T.; Nazriq, N. M. K.; Irisawa, T. [Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)

    2016-03-15

    A clean tungsten (W) tip apex with a robust atomic plane is required for producing a stable tunneling electron emission under strong electric fields. Because a tip apex fabricated from a wire by aqueous chemical etching is covered by impurity layers, heating treatment in ultra-high vacuum is experimentally known to be necessary. However, strong heating frequently melts the tip apex and causes unstable electron emissions. We investigated quantitatively the tip apex and found a useful method to prepare a tip with stable tunneling electron emissions by controlling electron-bombardment heating power. Careful characterizations of the tip structures were performed with combinations of using field emission I–V curves, scanning electron microscopy, X-ray diffraction (transmitted Debye-Scherrer and Laue) with micro-parabola capillary, field ion microscopy, and field emission microscopy. Tips were chemically etched from (1) polycrystalline W wires (grain size ∼1000 nm) and (2) long-time heated W wires (grain size larger than 1 mm). Heating by 10-40 W (10 s) was found to be good enough to remove oxide layers and produced stable electron emission; however, around 60 W (10 s) heating was threshold power to increase the tip radius, typically +10 ± 5 nm (onset of melting). Further, the grain size of ∼1000 nm was necessary to obtain a conical shape tip apex.

  15. Reduced atomic shadowing in HiPIMS: Role of the thermalized metal ions

    Science.gov (United States)

    Oliveira, João Carlos; Ferreira, Fábio; Anders, André; Cavaleiro, Albano

    2018-03-01

    In magnetron sputtering, the ability to tailor film properties depends primarily on the control of the flux of particles impinging on the growing film. Among deposition mechanisms, the shadowing effect leads to the formation of a rough surface and a porous, columnar microstructure. Re-sputtered species may be re-deposited in the valleys of the films surface and thereby contribute to a reduction of roughness and to fill the underdense regions. Both effects are non-local and they directly compete to shape the final properties of the deposited films. Additional control of the bombarding flux can be obtained by ionizing the sputtered flux, because ions can be controlled with respect to their energy and impinging direction, such as in High-Power Impulse Magnetron Sputtering (HiPIMS). In this work, the relation between ionization of the sputtered species and thin film properties is investigated in order to identify the mechanisms which effectively influence the shadowing effect in Deep Oscillation Magnetron Sputtering (DOMS), a variant of HiPIMS. The properties of two Cr films deposited using the same averaged target power by d.c. magnetron sputtering and DOMS have been compared. Additionally, the angle distribution of the Cr species impinging on the substrate was simulated using Monte Carlo-based programs while the energy distribution of the energetic particles bombarding the substrate was evaluated by energy-resolved mass analysis. It was found that the acceleration of the thermalized chromium ions at the substrate sheath in DOMS significantly reduces the high angle component of their impinging angle distribution and, thus, efficiently reduces atomic shadowing. Therefore, a high degree of ionization in HiPIMS results in almost shadowing effect-free film deposition and allows us to deposit dense and compact films without the need of high energy particle bombardment during growth.

  16. Treatment of PVC using an alternative low energy ion bombardment procedure

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, Elidiane C., E-mail: elidiane@sorocaba.unesp.br [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil); Santos, Nazir M. dos; Bortoleto, Jose Roberto R.; Durrant, Steven F. [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil); Schreiner, Wido H. [Laboratorio de Interfaces e Filmes Finos, Universidade Federal de Parana (UFPR), C.P. 19044, 81531-990, Curitiba, PR (Brazil); Honda, Roberto Y. [Laboratorio de Plasmas, Universidade Estadual Paulista (UNESP), Departamento de Fisica e Quimica, 12516-410, Guaratingueta, SP (Brazil); Cassia C Rangel, Rita de; Cruz, Nilson C. [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil)

    2011-12-15

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  17. Impact spherules as a record of an ancient heavy bombardment of Earth.

    Science.gov (United States)

    Johnson, B C; Melosh, H J

    2012-05-03

    Impact craters are the most obvious indication of asteroid impacts, but craters on Earth are quickly obscured or destroyed by surface weathering and tectonic processes. Earth’s impact history is inferred therefore either from estimates of the present-day impactor flux as determined by observations of near-Earth asteroids, or from the Moon’s incomplete impact chronology. Asteroids hitting Earth typically vaporize a mass of target rock comparable to the projectile’s mass. As this vapour expands in a large plume or fireball, it cools and condenses into molten droplets called spherules. For asteroids larger than about ten kilometres in diameter, these spherules are deposited in a global layer. Spherule layers preserved in the geologic record accordingly provide information about an impact even when the source crater cannot be found. Here we report estimates of the sizes and impact velocities of the asteroids that created global spherule layers. The impact chronology from these spherule layers reveals that the impactor flux was significantly higher 3.5 billion years ago than it is now. This conclusion is consistent with a gradual decline of the impactor flux after the Late Heavy Bombardment.

  18. From crater functions to partial differential equations: a new approach to ion bombardment induced nonequilibrium pattern formation.

    Science.gov (United States)

    Norris, Scott A; Brenner, Michael P; Aziz, Michael J

    2009-06-03

    We develop a methodology for deriving continuum partial differential equations for the evolution of large-scale surface morphology directly from molecular dynamics simulations of the craters formed from individual ion impacts. Our formalism relies on the separation between the length scale of ion impact and the characteristic scale of pattern formation, and expresses the surface evolution in terms of the moments of the crater function. We demonstrate that the formalism reproduces the classical Bradley-Harper results, as well as ballistic atomic drift, under the appropriate simplifying assumptions. Given an actual set of converged molecular dynamics moments and their derivatives with respect to the incidence angle, our approach can be applied directly to predict the presence and absence of surface morphological instabilities. This analysis represents the first work systematically connecting molecular dynamics simulations of ion bombardment to partial differential equations that govern topographic pattern-forming instabilities.

  19. Nano-scale pattern formation on the surface of HgCdTe produced by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.B.; Gudymenko, A.I.; Kladko, V.P.; Korchevyi, A.A.; Savkina, R.K.; Sizov, F.F.; Udovitska, R.S. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kiev (Ukraine)

    2015-08-15

    Presented in this work are the results concerning formation of nano-scale patterns on the surface of a ternary compound Hg{sub 1-x}Cd{sub x}Te (x ∝ 0.223). Modification of this ternary chalcogenide semiconductor compound was performed using the method of oblique-incidence ion bombardment with silver ions, which was followed by low-temperature treatment. The energy and dose of implanted ions were 140 keV and 4.8 x 10{sup 13} cm{sup -2}, respectively. Atomic force microscopy methods were used for the surface topography characterization. The structural properties of MCT-based structure was analyzed using double and triple crystal X-ray diffraction to monitor the disorder and strain of the implanted region as a function of processing conditions. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Enhanced End-Contacts by Helium Ion Bombardment to Improve Graphene-Metal Contacts

    Directory of Open Access Journals (Sweden)

    Kunpeng Jia

    2016-08-01

    Full Text Available Low contact resistance between graphene and metals is of paramount importance to fabricate high performance graphene-based devices. In this paper, the impact of both defects induced by helium ion (He+ bombardment and annealing on the contact resistance between graphene and various metals (Ag, Pd, and Pt were systematically explored. It is found that the contact resistances between all metals and graphene are remarkably reduced after annealing, indicating that not only chemically adsorbed metal (Pd but also physically adsorbed metals (Ag and Pt readily form end-contacts at intrinsic defect locations in graphene. In order to further improve the contact properties between Ag, Pd, and Pt metals and graphene, a novel method in which self-aligned He+ bombardment to induce exotic defects in graphene and subsequent thermal annealing to form end-contacts was proposed. By using this method, the contact resistance is reduced significantly by 15.1% and 40.1% for Ag/graphene and Pd/graphene contacts with He+ bombardment compared to their counterparts without He+ bombardment. For the Pt/graphene contact, the contact resistance is, however, not reduced as anticipated with He+ bombardment and this might be ascribed to either inappropriate He+ bombardment dose, or inapplicable method of He+ bombardment in reducing contact resistance for Pt/graphene contact. The joint efforts of as-formed end-contacts and excess created defects in graphene are discussed as the cause responsible for the reduction of contact resistance.

  1. Efficient and rapid C. elegans transgenesis by bombardment and hygromycin B selection.

    Directory of Open Access Journals (Sweden)

    Inja Radman

    Full Text Available We report a simple, cost-effective, scalable and efficient method for creating transgenic Caenorhabditis elegans that requires minimal hands-on time. The method combines biolistic bombardment with selection for transgenics that bear a hygromycin B resistance gene on agar plates supplemented with hygromycin B, taking advantage of our observation that hygromycin B is sufficient to kill wild-type C. elegans at very low concentrations. Crucially, the method provides substantial improvements in the success of bombardments for isolating transmitting strains, the isolation of multiple independent strains, and the isolation of integrated strains: 100% of bombardments in a large data set yielded transgenics; 10 or more independent strains were isolated from 84% of bombardments, and up to 28 independent strains were isolated from a single bombardment; 82% of bombardments yielded stably transmitting integrated lines with most yielding multiple integrated lines. We anticipate that the selection will be widely adopted for C. elegans transgenesis via bombardment, and that hygromycin B resistance will be adopted as a marker in other approaches for manipulating, introducing or deleting DNA in C. elegans.

  2. Determination of effective atomic numbers from mass attenuation coefficients of tissue-equivalent materials in the energy range 60 keV-1.33 MeV

    Science.gov (United States)

    Amin, Noorfatin Aida B.; Zukhi, J.; Kabir, N. A.; Zainon, R.

    2017-05-01

    The main aim of this study was to establish a cost-effective tissue-equivalent material for phantom fabrication. Effective atomic numbers (Zeff) and effective electron densities (Neff) were calculated based on mass attenuation coefficient values. The linear and mass attenuation coefficients of two samples of paraffin wax and NaCl compositions were measured using Si detector for NaI (Tl) detector of 1.5” resources. Radioactive source was placed in front of detector and the sample was placed between the source and the photomultiplier tube (PMT) of the detector. The real time was set for 6000 seconds. The photopeak, full width at half maximum (FWHM) and net area of photopeak were measured using Meastro software. The attenuation coefficient values obtained from this study were used to calculate Zeff and Neff of paraffin wax and NaCl compositions. The measured results were compared with the theoretical values from XCOM and ICRU Report 44. The relative percentage difference of mass attenuation coefficients between experimental and human tissue for both paraffin wax and NaCl mixture are below 5%, whereas the relative percentage difference of Zeff and Neff are above 5%. The measured values of Zeff and Neff of paraffin wax and NaCl help us to establish the optimal mixtures to fabricate a cost-effective tissue-equivalent material.

  3. Imaging Dirac-mass disorder from magnetic dopant atoms in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3.

    Science.gov (United States)

    Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J L; Zhong, Ruidan; Schneeloch, John A; Liu, Tiansheng; Valla, Tonica; Tranquada, John M; Gu, Genda; Davis, J C Séamus

    2015-02-03

    To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a "Dirac-mass gap" in their spectrum by breaking time-reversal symmetry. Use of magnetic dopant atoms to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the magnetic dopant atoms influence the Dirac-mass gap at the atomic scale or, conversely, whether the ferromagnetic interactions between dopant atoms are influenced by the topological surface states. Here we image the locations of the magnetic (Cr) dopant atoms in the ferromagnetic TI Cr0.08(Bi0.1Sb0.9)1.92Te3. Simultaneous visualization of the Dirac-mass gap Δ(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr atom areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of Δ(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship [Formula: see text] is confirmed throughout and exhibits an electron-dopant interaction energy J* = 145 meV·nm(2). These observations reveal how magnetic dopant atoms actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.

  4. Modification of the saturation magnetization of exchange bias thin film systems upon light-ion bombardment.

    Science.gov (United States)

    Huckfeldt, Henning; Gaul, Alexander; David Müglich, Nicolas; Holzinger, Dennis; Nissen, Dennis; Albrecht, Manfred; Emmrich, Daniel; Beyer, André; Gölzhäuser, Armin; Ehresmann, Arno

    2017-03-29

    The magnetic modification of exchange bias materials by 'ion bombardment induced magnetic patterning' has been established more than a decade ago. To understand these experimental findings several theoretical models were introduced. Few investigations, however, did focus on magnetic property modifications caused by effects of ion bombardment in the ferromagnetic layer. In the present study, the structural changes occurring under ion bombardment were investigated by Monte-Carlo simulations and in experiments. A strong reduction of the saturation magnetization scaling linearly with increasing ion doses is observed and our findings suggest that it is correlated to the swelling of the layer material based on helium implantation and vacancy creation.

  5. Initialization of unidirectional anisotropy in a ferromagnet antiferromagnet bilayer by keV-He ion bombardment

    Science.gov (United States)

    Engel, D.; Ehresmann, A.; Schmalhorst, J.; Sacher, M.; Höink, V.; Reiss, G.

    2005-06-01

    A polycrystalline Cu/Ni80Fe20/Mn83Ir17/Co/AlOx ferromagnet-antiferromagnet layer system grown without applying an external magnetic field shows no unidirectional anisotropy in the as-prepared state. After 10 keV-He ion bombardment in an external in-plane magnetic field, a clear unidirectional anisotropy collinear to the magnetic field direction during bombardment is observed, indicating that ion bombardment can be used for this system to initialize the unidirectional exchange anisotropy. The magnetization reversal processes for various ion doses are discussed, based on longitudinal magnetooptical Kerr-effect measurements.

  6. Cometary impact rates on the Moon and planets during the late heavy bombardment

    Science.gov (United States)

    Rickman, H.; Wiśniowski, T.; Gabryszewski, R.; Wajer, P.; Wójcikowski, K.; Szutowicz, S.; Valsecchi, G. B.; Morbidelli, A.

    2017-02-01

    Context. The Nice model predicts that the trans-planetary planetesimal disk made a large or even dominant contribution to the cratering in the inner solar system during the late heavy bombardment (LHB). In the presence of evidence that lunar craters and mare basins may be mainly of asteroidal origin, there is a dilemma of the missing comets that is not yet resolved. Aims: We aim to revisit the problem of cometary impact rates on the Moon and the terrestrial planets during the LHB with a flexible model, allowing us to study the influences of physical destruction of comets, the mass of the primordial disk, and the distribution of this mass over the entire size range. Methods: We performed a Monte Carlo study of the dynamics of the cometary LHB projectiles and derive the impact rates by calculating individual collision probabilities for a huge sample of projectile orbits. We used Minimum Orbit Intersection Distances (MOIDs) according to a new scheme introduced here. Different calculations were performed using different models for the physical evolution of comet nuclei and for the properties of the primordial, trans-planetary disk. Results: Based on the capture probability of Jupiter Trojans, we find a best fit radius of the largest LHB comet impacting the Moon for a low-mass primordial disk. For this disk mass, the LHB cratering of the Moon, Mercury and Mars were dominated by asteroids. However, some smaller lunar maria were likely preceded by comet impacts. The volatile delivery to the Earth and Mars by LHB comets was much less than their water inventories. Conclusions: There is no excessive cometary cratering, if the LHB was caused by a late planetary instability in the Nice Model. The Earth and Mars obtained their water very early in their histories. The Noachian water flows on Mars cannot be attributed to the arrival of LHB-related H2O or CO2.

  7. Exploiting flow injection and sequential injection for trace metal determinations in conjunction with detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    Despite their excellent analytical chemical capacities, Electrothermal Atomic Absorption Spectrometry (ETAAS) and Inductively Coupled Plasma Mass Spectrometry (ICPMS), nevertheless, often require suitable pretreatment of the sample material in order to obtain the necessary sensitivity...... and selectivity. Either in order to separate/preconcentrate the analyte material, or because of the presence of potentially interfering matrix constituents. Such pretreatments are advantageously performed in flow injection (FI) or sequential injection (SI) manifolds, where all appropriate unit operations can......, such as liquid-liquid extraction, (co)precipitation with collection in knotted reactors, adsorption, hydride generation, or the use of ion-exchange columns. Apart from hydride generation, where the analyte is converted into a gaseous species, the common denominator for these approaches is that the analyte...

  8. Self-terminated etching of GaN with a high selectivity over AlGaN under inductively coupled Cl2/N2/O2 plasma with a low-energy ion bombardment

    Science.gov (United States)

    Zhong, Yaozong; Zhou, Yu; Gao, Hongwei; Dai, Shujun; He, Junlei; Feng, Meixin; Sun, Qian; Zhang, Jijun; Zhao, Yanfei; DingSun, An; Yang, Hui

    2017-10-01

    Etching of GaN/AlGaN heterostructure by O-containing inductively coupled Cl2/N2 plasma with a low-energy ion bombardment can be self-terminated at the surface of the AlGaN layer. The estimated etching rates of GaN and AlGaN were 42 and 0.6 nm/min, respectively, giving a selective etching ratio of 70:1. To study the mechanism of the etching self-termination, detailed characterization and analyses were carried out, including X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It was found that in the presence of oxygen, the top surface of the AlGaN layer was converted into a thin film of (Al,Ga)Ox with a high bonding energy, which effectively prevented the underlying atoms from a further etching, resulting in a nearly self-terminated etching. This technique enables a uniform and reproducible fabrication process for enhancement-mode high electron mobility transistors with a p-GaN gate.

  9. The ballistic performance of the bombard Mons Meg

    Directory of Open Access Journals (Sweden)

    Ian Lewtas

    2016-04-01

    Full Text Available The bombard Mons Meg, located in Edinburgh Castle, with a diameter of 19 inches (48 cm, was one of the largest calibre cannons ever built. Constructed in 1449 and presented to King James II of Scotland in 1454, Mons Meg was used in both military and ceremonial roles in Scotland until its barrel burst in 1680. This paper examines the history, internal, external and terminal ballistics of the cannon and its shot. The likely muzzle velocity was estimated by varying the propellant type and the cannon profile was investigated to identify weak spots in the design that may have led to its failure. Using the muzzle velocity calculated from the internal ballistics, simulations were performed with granite and sandstone shot for varying launch angle and ground temperature. The likely trajectory and range of the cannonballs are described. The internal and external ballistics informed the initial conditions of the terminal ballistic impact scenarios. The performance of the cannonball against both period and modern targets, in the form of a pseudo-castle wall and a monolithic concrete target, respectively, were simulated and are presented and discussed.

  10. Hydrogen ion bombardment damage in stainless steel mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, A.I. [National Technical University ' KhPI' , Kharkov, 61002 Kharkov (Ukraine); Bardamid, A.F. [T. Shevchenko National University, Kiev (Ukraine); Davis, J.W. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada); Haasz, A.A. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada)]. E-mail: aahaasz@utias.utoronto.ca; Konovalov, V.G. [NSC KIPT, 61108 Kharkov (Ukraine); Kudlenko, A.D. [National Technical University ' KhPI' , Kharkov, 61002 Kharkov (Ukraine); Poon, M. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada); Slatin, K.A. [National Technical University ' KhPI' , Kharkov, 61002 Kharkov (Ukraine); Voitsenya, V.S. [NSC KIPT, 61108 Kharkov (Ukraine)

    2005-10-15

    Experiments have been performed to evaluate the changes in surface structure and the resulting effects on the optical properties of stainless steel due to hydrogen ion irradiation. Stainless steel (SS) is a standard material used for in-vessel components, including the first mirrors (FMs), in some current generation fusion devices. Optical microscopy, interferometry, scanning electron microscopy (SEM) and ellipsometry were used to characterize the surfaces. Results are presented for the bombardment of SS mirrors with H{sub 3}{sup +} ions having various fixed energies (0.3, 0.65, and 1.5keV/H{sup +}), with ion flux densities of (0.5-2)x10{sup 20} H{sup +}/m{sup 2}s and fluences of {approx}2.2x10{sup 24} H{sup +}/m{sup 2}. Variation of the ion energy at a constant fluence had a considerable effect on the damage structure that forms on the SS mirror surfaces. Possible mechanisms for the ion energy effect on the surface are discussed and a model of the damaged surface layer is proposed.

  11. Back-bombardment compensation in microwave thermionic electron guns

    Directory of Open Access Journals (Sweden)

    Jeremy M. D. Kowalczyk

    2014-12-01

    Full Text Available The development of capable, reliable, and cost-effective compact electron beam sources remains a long-standing objective of the efforts to develop the accelerator systems needed for on-site research and industrial applications ranging from electron beam welding to high performance x-ray and gamma ray light sources for element-resolved microanalysis and national security. The need in these applications for simplicity, reliability, and low cost has emphasized solutions compatible with the use of the long established and commercially available pulsed microwave rf sources and L-, S- or X-band linear accelerators. Thermionic microwave electron guns have proven to be one successful approach to the development of the electron sources for these systems providing high macropulse average current beams with picosecond pulse lengths and good emittance out to macropulse lengths of 4–5 microseconds. But longer macropulse lengths are now needed for use in inverse-Compton x-ray sources and other emerging applications. We describe in this paper our approach to extending the usable macropulse current and pulse length of these guns through the use of thermal diffusion to compensate for the increase in cathode surface temperature due to back-bombardment.

  12. Modelling and simulation of surface morphology driven by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Yewande, E.O.

    2006-05-02

    Non-equilibrium surfaces, at nanometer length scales, externally driven via bombardment with energetic particles are known to exhibit well ordered patterns with a variety of applications in nano-technology. These patterns emerge at time scales on the order of minutes. Continuum theory has been quite successful in giving a general picture of the processes that interplay to give the observed patterns, as well as how such competition might determine the properties of the nanostructures. However, continuum theoretical descriptions are ideal only in the asymptotic limit. The only other theoretical alternative, which happens to be more suitable for the characteristic length-and time-scales of pattern formation, is Monte Carlo simulation. In this thesis, surface morphology is studied using discrete solid-on-solid Monte Carlo models of sputtering and surface diffusion. The simulations are performed in the context of the continuum theories and experiments. In agreement with the experiments, the ripples coarsen with time and the ripple velocity exhibits a power-law behaviour with the ripple wavelength, in addition, the exponent was found to depend on the simulation temperature, which suggests future experimental studies of flux dependence. Moreover, a detailed exploration of possible topographies, for different sputtering conditions, corresponding to different materials, was performed. And different surface topographies e.g. holes, ripples, and dots, were found at oblique incidence, without sample rotation. With sample rotation no new topography was found, its only role being to destroy any inherent anisotropy in the system. (orig.)

  13. Stable Transformation of the Saintpaulia ionantha by Particle Bombardment.

    Science.gov (United States)

    Ghorbanzade, Zahra; Ahmadabadi, Mohammad

    2015-03-01

    A highly efficient genetic transformation system is essential for a successful genetic manipulation of the African violet (Saintpaulia ionantha Wendl.). Developing a particle bombardment-based genetic transformation system for the African violet. A local cultivar of the African violet from Guilan province was used for transformation experiments. The pFF19G and pBin61-Ech42 vectors were used for transient and stable transformation experiments, respectively. The PCR and RT-PCR techniques were used to verify transgene presence and transcript levels in candidate transgenic lines, respectively. Using leaf explants as target tissues, we transferred an endochitinase gene cDNA into African violet. Transgenic plants were regenerated on selection medium at a reasonable frequency (in average, one stable transgenic line per shot). Molecular analysis of transgenic plants by PCR and RT-PCR techniques confirmed successful integration and expression of transgene in several independent transgenic lines. Our results provide an efficient stable transformation system for genetic transformation of African violet.

  14. Hydrogen ion bombardment damage in stainless steel mirrors

    Science.gov (United States)

    Belyaeva, A. I.; Bardamid, A. F.; Davis, J. W.; Haasz, A. A.; Konovalov, V. G.; Kudlenko, A. D.; Poon, M.; Slatin, K. A.; Voitsenya, V. S.

    2005-10-01

    Experiments have been performed to evaluate the changes in surface structure and the resulting effects on the optical properties of stainless steel due to hydrogen ion irradiation. Stainless steel (SS) is a standard material used for in-vessel components, including the first mirrors (FMs), in some current generation fusion devices. Optical microscopy, interferometry, scanning electron microscopy (SEM) and ellipsometry were used to characterize the surfaces. Results are presented for the bombardment of SS mirrors with H3+ ions having various fixed energies (0.3, 0.65, and 1.5 keV/H+), with ion flux densities of (0.5-2) × 1020 H+/m2s and fluences of ∼2.2 × 1024 H+/m2. Variation of the ion energy at a constant fluence had a considerable effect on the damage structure that forms on the SS mirror surfaces. Possible mechanisms for the ion energy effect on the surface are discussed and a model of the damaged surface layer is proposed.

  15. Examination of Organic Vapor Adsorption onto Alkali Metal and Halide Atomic Ions by using Ion Mobility Mass Spectrometry.

    Science.gov (United States)

    Maiβer, Anne; Hogan, Christopher J

    2017-11-03

    We utilize ion mobility mass spectrometry with an atmospheric pressure differential mobility analyzer coupled to a time-of-flight mass spectrometer (DMA-MS) to examine the formation of ion-vapor molecule complexes with seed ions of K+ , Rb+ , Cs+ , Br- , and I- exposed to n-butanol and n-nonane vapor under subsaturated conditions. Ion-vapor molecule complex formation is indicated by a shift in the apparent mobility of each ion. Measurement results are compared to predicted mobility shifts based upon the Kelvin-Thomson equation, which is commonly used in predicting rates of ion-induced nucleation. We find that n-butanol at saturation ratios as low as 0.03 readily binds to all seed ions, leading to mobility shifts in excess of 35 %. Conversely, the binding of n-nonane is not detectable for any ion for saturation ratios in the 0-0.27 range. An inverse correlation between the ionic radius of the initial seed and the extent of n-butanol uptake is observed, such that at elevated n-butanol concentrations, the smallest ion (K+ ) has the smallest apparent mobility and the largest (I- ) has the largest apparent mobility. Though the differences in behavior of the two vapor molecules types examined and the observed effect of ionic seed radius are not accounted for by the Kelvin-Thomson equation, its predictions are in good agreement with measured mobility shifts for Rb+ , Cs+ , and Br- in the presence of n-butanol (typically within 10 % of measurements). © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  16. Into the atom and beyond

    CERN Document Server

    1989-01-01

    Magnifying an atom to football pitch size. The dense nucleus, carrying almost all the atomic mass, is much smaller than the ball. The players (the electrons) would see something about the size of a marble!

  17. The interpretation of ellipsometric measurements of ion bombardment of noble gases on semiconductor surfaces

    NARCIS (Netherlands)

    Holtslag, A.H.M.; Slager, U.C.; van Silfhout, Arend

    1985-01-01

    Low energy noble gas ion bombardment and thermal desorption studies were carried out on Si(111) and analysed, in situ, using spectroscopic ellipsometry. The amorphous layer thickness and implanted noble gas fraction were calculated.

  18. Saturn’s ring age from bombardment simulation and reflectance fit to Cassini UVIS spectra

    Science.gov (United States)

    Elliott, Joshua Peter; Esposito, Larry; Bradley, Eric Todd

    2017-10-01

    The age of Saturn’s rings is open question. Our understanding of this question depends heavily on the rate at which infalling meteoritic material impacts the rings, which is a matter of some debate. Recent estimates of this mass flux are between an order of magnitude higher and lower than the estimate given by Cuzzi and Estrada 1998. Given this range, we perform a meteoritic bombardment simulation, using our stochastic Markov-chain based model, which yields fractional-pollution curves over time for the B and C rings of Saturn. Next, using Hapke’s 2012 model for bidirectional reflectance for an intimate mixture of water-ice and pollutant grains, we perform a non-linear least-squares fit to Cassini UVIS data with two free parameters, fractional pollution and surface roughness of the ring particles, with a correction for the optical depth of the rings, to determine the estimated fractional pollution observed by UVIS. We perform this fit with two pollutants, amorphous carbon, and cometary material measured by the Rosetta Alice UV spectrometer of comet 67P/Churyumov-Gerasimenko. The fractional pollution value returned by our fit is then used to interpolate ring age along the fractional pollution curves returned by our Markov-chain simulation.

  19. Influence of the ion bombardment of O{sub 2} plasmas on low-k materials

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick, E-mail: verdonck@imec.be [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Samara, Vladimir [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Goodyear, Alec [Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferchichi, Abdelkarim; Van Besien, Els; Baklanov, Mikhail R. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Braithwaite, Nicholas [Open University, Department of Physics and Astronomy, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2011-10-31

    In this study, special tests were devised in order to investigate the influence of ion bombardment on the damage induced in low-k dielectrics by oxygen plasmas. By placing a sample that suffered a lot of ion bombardment and one which suffered little ion bombardment simultaneously in the same plasma, it was possible to verify that ion bombardment in fact helped to protect the low-k film against oxygen plasma induced damage. Exhaustive analyses (ellipsometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, porosimetry, capacitance-voltage (C-V) measurements, water contact angle analysis) show that ion bombardment induced the formation of a denser top layer in the film, which then hampered further penetration of active oxygen species deeper into the bulk. This was further confirmed by other tests combining capacitively and inductively coupled plasmas. Therefore, it was possible to conclude that, at least for these plasmas, ion bombardment may help to reduce plasma induced damage to low-k materials.

  20. Back bombardment for dispenser and lanthanum hexaboride cathodes

    Directory of Open Access Journals (Sweden)

    Mahmoud Bakr

    2011-06-01

    Full Text Available The back bombardment (BB effect limits wide usage of thermionic rf guns. The BB effect induces not only ramping-up of a cathode’s temperature and beam current, but also degradation of cavity voltage and beam energy during a macropulse. This paper presents a comparison of the BB effect for the case of dispenser tungsten-base (DC and lanthanum hexaboride (LaB_{6} thermionic rf gun cathodes. For each, particle simulation codes are used to simulate the BB effect and electron beam dynamics in a thermionic rf gun cathode. A semiempirical equation is also used to investigate the stopping range and deposited heat power of BB electrons in the cathode material. A numerical simulation method is used to calculate the change of the cathode temperature and current density during a single macropulse. This is done by solving two differential equations for the rf gun cavity equivalent circuit and one-dimensional thermal diffusion equation. High electron emission and small beam size are required for generation of a high-brightness electron beam, and so in this work the emission properties of the cathode are taken into account. Simulations of the BB effect show that, for a pulse of 6  μs duration, the DC cathode experiences a large change in the temperature compared with LaB_{6}, and a change in current density 6 times higher. Validation of the simulation results is performed using experimental data for beam current beyond the gun exit. The experimental data is well reproduced using the simulation method.

  1. Photon emission produced by Kr{sup +} ions bombardment of Cr and Cr{sub 2}O{sub 3} targets

    Energy Technology Data Exchange (ETDEWEB)

    Boujlaidi, A. El, E-mail: a.elboujlaidi@uca.ma [Equipe de Spectroscopie and Imagerie Atomiques des Matériaux, Université Cadi Ayyad, Marrakech (Morocco); Hammoum, K. [Laboratoire de Mécanique, Structures et Energétique, Université Mouloud Mammeri de Tizi-Ouzou (Algeria); Jadoual, L.; Jourdani, R. [Equipe de Spectroscopie and Imagerie Atomiques des Matériaux, Université Cadi Ayyad, Marrakech (Morocco); Ait El Fqih, M. [Equipe de Spectroscopie and Imagerie Atomiques des Matériaux, Université Cadi Ayyad, Marrakech (Morocco); Ecole Nationale Supérieure d’Arts et Métiers (ENSAM), Université Hassan II Mohammedia – Casablanca (Morocco); Aouchiche, H. [Laboratoire de Mécanique, Structures et Energétique, Université Mouloud Mammeri de Tizi-Ouzou (Algeria); Kaddouri, A. [Equipe de Spectroscopie and Imagerie Atomiques des Matériaux, Université Cadi Ayyad, Marrakech (Morocco)

    2015-01-15

    The sputter induced photon spectroscopy technique was used to study the luminescence spectra of the species sputtered from chromium powder and its oxide Cr{sub 2}O{sub 3}, during 5 keV Kr{sup +} ions bombardment in vacuum better than 10{sup −7} torr. The optical spectra recorded between 350 and 470 nm exhibit discrete lines which are attributed to neutral excited atoms of chromium (Cr I lines). The experiments are also performed under 10{sup −5} torr ultra pure oxygen partial pressure. The results demonstrate that the measured intensities of the emitted photons are always higher in the presence of oxygen and even higher than those obtained for Cr{sub 2}O{sub 3} target. In the presence of oxygen vapor we assume that an oxide film is formed on the chromium surface which is responsible of the increase of photon emission. This variation in the intensities is correctly explained in the model of electron transfer processes between the excited sputtered atom and the bombarded surface. This model suggests that the structure formed on the Cr surface in the case of oxygenated chromium is closer to that of Cr{sub 2}O{sub 3} oxide.

  2. Non-thermodynamic approach to including bombardment-induced post-cascade redistribution of point defects in dynamic Monte Carlo code

    CERN Document Server

    Ignatova, V A; Katardjiev, I V

    2003-01-01

    The redistribution of the elements as a result of atomic relocations produced by the ions and the recoils due to the ballistic and transport processes is investigated by making use of a dynamic Monte Carlo code. Phenomena, such as radiation-enhanced diffusion (RED) and bombardment-induced segregation (BIS) triggered by the ion bombardment may also contribute to the migration of atoms within the target. In order to include both RED and BIS in the code, we suggest an approach which is considered as an extension of the binary collision approximation, i.e. it takes place 'simultaneously' with the cascade and acts as a correction to the particle redistribution for low energies. Both RED and BIS models are based on the common approach to treat the transport processes as a result of a random migration of point defects (vacancies and interstitials) according to a probability given by a pre-defined Gaussian. The models are tested and the influence of the diffusion and segregation is illustrated in the cases of 12 keV ...

  3. Cobalt speciation study in the cobalt-cysteine system by electrospray ionization mass spectrometry and anion-exchange chromatography inductively coupled plasma atomic emission spectrometry.

    Science.gov (United States)

    Bresson, Carole; Colin, Christèle; Chartier, Frédéric; Moulin, Christophe

    2005-05-01

    This paper describes the ability of the combination of electrospray ionization mass spectrometry (ESI-MS) and anion-exchange chromatography coupled with inductively coupled plasma atomic emission spectrometry (AEC-ICP-AES) for cobalt speciation study in the binary cobalt-cysteine system. ESI-MS, allowing the identification and the characterization of the analytes, is used as a technique complementary to AEC-ICP-AES, providing elemental information on the separated species. The methods have been developed through the study of samples containing Co2+ and 1-fold to 5-fold molar ratios of cysteine over a pH range 2.5 to 11. In each case, cobalt-cysteine complexes were characterized by ESI-MS in negative ion mode. AEC-ICP-AES allowed further separation and detection of the cobalt species previously characterized. The strong influence of pH and ligand-to-metal ratios on the nature and stoichiometry of the species is demonstrated. For the first time, a direct experimental speciation diagram of cobalt species has been established owing to these analytical techniques. This work is a promising basis for the speciation analysis of cobalt, since a good knowledge of cobalt speciation is of prime importance to better understanding its fate in biological and environmental media.

  4. Observing Planets and Small Bodies in Sputtered High Energy Atom (SHEA) Fluxes

    Science.gov (United States)

    Milillo, A.; Orsini, S.; Hsieh, K. C.; Baragiola, R.; Fama, M.; Johnson, R.; Mura, A.; Plainaki, Ch.; Sarantos, M.; Cassidy, T. A.; hide

    2012-01-01

    The evolution of the surfaces of bodies unprotected by either strong magnetic fields or thick atmospheres in the Solar System is caused by various processes, induced by photons, energetic ions and micrometeoroids. Among these processes, the continuous bombardment of the solar wind or energetic magnetospheric ions onto the bodies may significantly affect their surfaces, with implications for their evolution. Ion precipitation produces neutral atom releases into the exosphere through ion sputtering, with velocity distribution extending well above the particle escape limits. We refer to this component of the surface ejecta as sputtered high-energy atoms (SHEA). The use of ion sputtering emission for studying the interaction of exposed bodies (EB) with ion environments is described here. Remote sensing in SHEA in the vicinity of EB can provide mapping of the bodies exposed to ion sputtering action with temporal and mass resolution. This paper speculates on the possibility of performing remote sensing of exposed bodies using SHEA The evolution of the surfaces of bodies unprotected by either strong magnetic fields or thick atmospheres in the Solar System is caused by various processes, induced by photons, energetic ions and micrometeoroids. Among these processes, the continuous bombardment of the solar wind or energetic magnetospheric ions onto the bodies may significantly affect their surfaces, with implications for their evolution. Ion precipitation produces neutral atom releases into the exosphere through ion sputtering, with velocity distribution extending well above the particle escape limits. We refer to this component of the surface ejecta as sputtered high-energy atoms (SHEA). The use of ion sputtering emission for studying the interaction of exposed bodies (EB) with ion environments is described here. Remote sensing in SHEA in the vicinity of EB can provide mapping of the bodies exposed to ion sputtering action with temporal and mass resolution. This paper

  5. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.D., E-mail: yuld@thep-center.org [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Phanchaisri, B. [Institute of Science and Technology Research, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Singkarat, S. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-05-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  6. ANALYTICAL MODELING OF ELECTRON BACK-BOMBARDMENT INDUCED CURRENT INCREASE IN UN-GATED THERMIONIC CATHODE RF GUNS

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Sun, Y. [Argonne; Harris, J. R. [AFRL, NM; Lewellen, J. W. [Los Alamos Natl. Lab.

    2016-09-28

    In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, fieldenhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

  7. Bohmian picture of Rydberg atoms

    Indian Academy of Sciences (India)

    lished the nearly elliptical shapes for the centre-of-mass motion in Rydberg atoms using numerical simulations, we show analytically that the Bohmian trajectories in Rydberg atoms are nearly ellipti- cal. Keywords. Rydberg atom; quantum trajectory. PACS No. 03.65.Ge. 1. Introduction. Ever since the advent of quantum ...

  8. The Impact Rate on Solar System Satellites During the Late Heavy Bombardment

    Science.gov (United States)

    Dones, Henry C. Luke; Levison, H. F.

    2012-10-01

    Nimmo and Korycansky (2012; henceforth NK12) found that if the outer Solar System underwent a Late Heavy Bombardment (LHB) in the Nice model, the mass striking the icy satellites at speeds up to tens of km/s would have vaporized so much ice that moons such as Mimas, Enceladus, and Miranda would have been devolatilized. NK12's possible explanations of this apparent discrepancy with observations include (1) the mass influx was a factor of 10 less than that in the Nice model; (2) the mass distribution of the impactors was top-heavy, so that luck might have saved some of the moons from suffering large, vapor-removing impacts; or (3) the inner moons formed after the LHB. NK12 calculated the mass influx onto the satellites from the lunar impact rate estimated by Gomes et al. (2005) and scaling factors calculated by Zahnle et al. (1998, 2003; also see Barr and Canup 2010). Production of vapor in hypervelocity impacts was calculated from Kraus et al. (2011). We are calculating impact rates onto the giant planets and their moons in the context of the "Nice II" model (Levison et al. 2011). We find that NK12's assumed influx is an overestimate, by an amount we are quantifying. We will discuss implications for the origin of icy satellites. We thank the NASA Lunar Science Institute (http://lunarscience.nasa.gov/) for support. Barr, A.C., Canup, R.M., Nature Geoscience 3, 164-167 (2010). Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A., Nature 435, 466-469 (2005). Kraus, R.G., Senft, L.E., Stewart, S.T., Icarus 214, 724-738 (2011). Levison, H.F., Morbidelli, A., Tsiganis, K., Nesvorný, D., Gomes, R., Astron. J. 142, article id. 152 (2011). Nimmo, F., Korycansky, D.G., Icarus 219, 508-510 (2012). Zahnle, K., Dones, L., Levison, H.F., Icarus 136, 202-222 (1998). Zahnle, K., Schenk, P., Levison, H.F., Dones, L., Icarus 163, 263-289 (2003).

  9. Inverse photoemission and LEED investigation of the ion-bombarded Ni(110) surface

    Science.gov (United States)

    Young, Benjamin; Warner, Jim; Heskett, David

    2012-02-01

    Ion bombardment of the clean Ni(110) surface is investigated by a combination of Inverse Photoemission Spectroscopy (IPES) with a Geiger-Muller detector and Low Energy Electron Diffraction (LEED) with a homebuilt video capture system. Disorder of the surface is induced by argon ion bombardment with various combinations of argon pressure and sputtering time. The intensity of the unoccupied surface state at ˜ 2eV above the Fermi level at the =Y point of the surface Brillouin zone decreases with increasing surface bombardment. Simultaneously, intensity profiles of diffraction spots in LEED exhibit broadening and a rising background level for increasing surface disorder. Multiple attempts at correlation between the results of the two techniques are presented.

  10. Particularities of LaB sub 6 behaviour under bombardment with helium and argon energetic ions

    CERN Document Server

    Lesnyakov, G G; Klyimenko, V M; Pershyin, V F

    2002-01-01

    The investigation results on the bombardment of LaB sub 6 of 18 - 26% porosity with 20 keV helium and 0.5 keV argon ions are presented. the main contribution to the erosion is made by the material removal from the surface, which confirms the earlier conclusions about weakness of boundary grain, pores, and formation of cracks and round dislocation etch pits. It is shown that, during the bombardment as a dose is increased, a layer is formed on the LaB sub 6 surface with a subsequent change of the relative content of two elements. It is determined when and where one can expect the formation of LaB sub 4 under bombardment of the surface.

  11. Influence of a Thiolate Chemical Layer on GaAs (100 Biofunctionalization: An Original Approach Coupling Atomic Force Microscopy and Mass Spectrometry Methods

    Directory of Open Access Journals (Sweden)

    Alex Bienaime

    2013-10-01

    Full Text Available Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly sensitive transducer with a specific bio-interface; which are the two essential parts of a biosensor. To optimize the biorecognition part; it is necessary to control protein coverage and the binding affinity of the protein layer on the GaAs surface. In this paper; we investigate the potential of a specific chemical interface composed of thiolate molecules with different chain lengths; possessing hydroxyl (MUDO; for 11-mercapto-1-undecanol (HS(CH211OH or carboxyl (MHDA; for mercaptohexadecanoic acid (HS(CH215CO2H end groups; to reconstitute a dense and homogeneous albumin (Rat Serum Albumin; RSA protein layer on the GaAs (100 surface. The protein monolayer formation and the covalent binding existing between RSA proteins and carboxyl end groups were characterized by atomic force microscopy (AFM analysis. Characterization in terms of topography; protein layer thickness and stability lead us to propose the 10% MHDA/MUDO interface as the optimal chemical layer to efficiently graft proteins. This analysis was coupled with in situ MALDI-TOF mass spectrometry measurements; which proved the presence of a dense and uniform grafted protein layer on the 10% MHDA/MUDO interface. We show in this study that a critical number of carboxylic docking sites (10% is required to obtain homogeneous and dense protein coverage on GaAs. Such a protein bio-interface is of fundamental importance to ensure a highly specific and sensitive biosensor.

  12. Comparison of atomic absorption, mass and X-ray spectrometry techniques using dissolution-based and solid sampling methods for the determination of silver in polymeric samples

    Energy Technology Data Exchange (ETDEWEB)

    Schrijver, Isabel de [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium); University College West-Flanders, Department of Industrial Engineering and Technology, Research group EnBiChem, Graaf Karel de Goedelaan 5, B-8500 Kortrijk (Belgium); Aramendia, Maite; Vincze, Laszlo [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium); Resano, Martin [University of Zaragoza, Department of Analytical Chemistry, Pedro Cerbuna 12, E-50009 Zaragoza (Spain); Dumoulin, Ann [University College West-Flanders, Department of Industrial Engineering and Technology, Research group EnBiChem, Graaf Karel de Goedelaan 5, B-8500 Kortrijk (Belgium); Vanhaecke, Frank [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium)], E-mail: Frank.Vanhaecke@UGent.be

    2007-11-15

    In this work, the capabilities and limitations of solid sampling techniques - laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), wavelength dispersive X-ray fluorescence spectrometry (WD-XRFS) and solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS) - for the determination of silver in polymers have been evaluated and compared to those of acid digestion and subsequent Ag determination using pneumatic nebulization ICPMS (PN-ICPMS) or flame AAS (FAAS). In a first stage, two dissolution procedures were examined: conventional acid digestion in a Kjeldahl flask and the combination of dry ashing and microwave-assisted digestion. Accurate results for Ag could be obtained, although occasionally, problems of analyte losses and/or incomplete dissolution were observed. LA-ICPMS shows potential for direct analysis of solid materials, but calibration was found to be difficult. A polypropylene sample was used as standard. This approach provided satisfactory results for other polypropylene samples and even for other types of plastics, provided that the {sup 13}C{sup +} signal was used as internal reference, correcting for variations in ablation efficiency. However, the results for polyoxymethylene were overestimated. Similar calibration problems appeared with WD-XRFS, due to differences in absorption efficiency of X-rays. In this case, the accuracy could be improved by using a matrix correction procedure, which however required the matrix composition to be known into sufficient detail. SS-ETAAS, proved to be a fast approach that allowed accurate determination of Ag in polymers using aqueous standard solutions for calibration. Due to the high Ag content and the excellent sensitivity, the use of a 3-field mode Zeeman-effect background correction system was essential for the extension of the working range.

  13. Genetic transformation of banana and plantain (Musa spp.) via particle bombardment.

    Science.gov (United States)

    Sági, L; Panis, B; Remy, S; Schoofs, H; De Smet, K; Swennen, R; Cammue, B P

    1995-05-01

    We have developed a simple protocol to allow the production of transgenic banana plants. Foreign genes were delivered into embryogenic suspension cells using accelerated particles coated with DNA. Bombardment parameters were optimized for a modified particle gun resulting in high levels of transient expression of the beta-glucuronidase gene in both banana and plantain cells. Bombarded banana cells were selected with hygromycin and regenerated into plants. Molecular and histochemical characterization of transformants revealed the stable integration of the transferred genes into the banana genome.

  14. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  15. Ion-Bombardment of Thin-Layers - the Effect on the Interface Roughness and Its X-Ray Reflectivity

    NARCIS (Netherlands)

    Puik, E. J.; van der Wiel, M. J.; Zeijlemaker, H.; Verhoeven, J.

    1992-01-01

    In this paper we report on experiments which indicate the necessity of the use of ion-beam bombardment for e-beam deposited multilayer x-ray coatings. Measurements are described in which ion bombardment (200-300 eV Ar+) is used to ion etch metal layers after initial deposition and during deposition

  16. Use of monoatomic and polyatomic projectiles for the characterisation of polylactic acid by static secondary ion mass spectrometry.

    Science.gov (United States)

    Boschmans, Bart; Van Royen, Pieter; Van Vaeck, Luc

    2005-01-01

    The application of polyatomic primary ions is a strongly developing branch of static secondary ion mass spectrometry (S-SIMS), since these projectiles allow a significant increase in the secondary ion yields to be achieved. However, the different limitations and possibilities of certain polyatomic primary ions for use on specific functional classes of samples are still not completely known. This paper compares the use of monoatomic and polyatomic primary ions in S-SIMS for thin layers of polylactic acid (PLA), obtained by spin-coating solutions on silicon wafers. Bombardment with Ga+, Xe+ and SF5+ primary ions allowed the contribution of the projectile mass and number of atoms in the gain in ion yield and molecular specificity (relative importance of high m/z and low m/z signals) to be assessed. Samples obtained by spin-coating solutions with increasing concentration showed that optimal layer thickness depended on the primary ion used. In comparison with the use of Ga+ projectiles, the yield of structural ions increased by a factor of about 1.5 to 2 and by about 7 to 12 when Xe+ and SF5+ primary ion bombardment were applied, respectively. A detailed fragmentation pattern was elaborated to interpret ion signal intensity changes for different projectiles in terms of energy deposition and collective processes in the subsurface, and the internal energy of radical and even-electron precursor ions. Copyright (c) 2005 John Wiley & Sons, Ltd.

  17. Enumeration of non-labile oxygen atoms in dissolved organic matter by use of ¹⁶O/ ¹⁸O exchange and Fourier transform ion-cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Kostyukevich, Yury; Kononikhin, Alexey; Zherebker, Alexander; Popov, Igor; Perminova, Irina; Nikolaev, Eugene

    2014-10-01

    We report a simple approach for enumeration of non-labile oxygen atoms in individual molecules of dissolved organic matter (DOM), using acid-catalyzed (16)O/(18)O exchange and ultrahigh-resolution Fourier-transform ion-cyclotron-resonance mass spectrometry (FTICR-MS). We found that by dissolving DOM in H2 (18)O at 95 °C for 20 days it is possible to replace all oxygen atoms of DOM molecules (excluding oxygen from ether groups) with (18)O. The number of exchanges in each molecule can be determined using high-resolution FTICR. Using the proposed method we identified the number of non-labile oxygen atoms in 231 molecules composing DOM. Also, using a previously developed hydrogen-deuterium (H/D)-exchange approach we identified the number of labile hydrogen atoms in 450 individual molecular formulas. In addition, we observed that several backbone hydrogen atoms can be exchanged for deuterium under acidic conditions. The method can be used for structural and chemical characterization of individual DOM molecules, comparing different DOM samples, and investigation of biological pathways of DOM in the environment.

  18. Reviews Book: Big Ben Book: Mini Weapons of Mass Destruction Equipment: Waves and Radiation Sample Pack Book: The Exploratorium Science Snackbook Book: Super Structures Book: The Universe and the Atom

    Science.gov (United States)

    2010-11-01

    WE RECOMMEND Mini Weapons of Mass Destruction A pictorial guide to making safe mini weapons Waves and Radiation Sample Pack Pack shines light on the electromagnetic spectrum The Exploratorium Science Snackbook Book is full of ideas for fascinating physics demonstrations Super Structures The science of bridges, buildings, dams and engineering WORTH A LOOK Big Ben The physics of the world-famous clock The Universe and the Atom A comprehensive guide to physics

  19. Effect of Ar bombardment on the electrical and optical properties of ...

    Indian Academy of Sciences (India)

    The influence of low-energy Ar ion beam irradiation on both electrical and optical properties of low-density polyethylene (LDPE) films is presented. The polymer films were bombarded with 320 keV Ar ions with fuences up to 1 × 10 15 cm − 2 . Electrical properties of LDPE films were measured and the effect of ion ...

  20. Transient expression of GUS in bombarded embryogenic longleaf, loblolly, and eastern white pine

    Science.gov (United States)

    Alex M. Diner; Allan Zipf; Rufina Ward; Yinghua Huang; George Brown

    1999-01-01

    Embryogenic tissue cultures derived from immature zygotic embryos of longleaf, loblolly, and eastern white pine were maintained in culture for up to 2 years, then bombarded with gold particles coated with a gene construct containing the GUS reporter gene fused to an adenine methyltransferase promoter from an algal virus. Physiological expression of GUS was observed in...

  1. Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability

    Science.gov (United States)

    Grimm, R. E.; Marchi, S.

    2018-03-01

    Intense bombardment is considered characteristic of the Hadean and early Archean eons, yet some detrital zircons indicate that near-surface water was present and thus at least intervals of clement conditions may have existed. We investigate the habitability of the top few kilometers of the subsurface by updating a prior approach to thermal evolution of the crust due to impact heating, using a revised bombardment history, a more accurate thermal model, and treatment of melt sheets from large projectiles (>100 km diameter). We find that subsurface habitable volume grows nearly continuously throughout the Hadean and early Archean (4.5-3.5 Ga) because impact heat is dissipated rapidly compared to the total duration and waning strength of the bombardment. Global sterilization was only achieved using an order of magnitude more projectiles in 1/10 the time. Melt sheets from large projectiles can completely resurface the Earth several times prior to ∼4.2 Ga but at most once since then. Even in the Hadean, melt sheets have little effect on habitability because cooling times are short compared to resurfacing intervals, allowing subsurface biospheres to be locally re-established by groundwater infiltration between major impacts. Therefore the subsurface is always habitable somewhere, and production of global steam or silicate-vapor atmospheres are the only remaining avenues to early surface sterilization by bombardment.

  2. The influence of argon ion bombardment on the electrical and optical properties of clean silicon surfaces

    NARCIS (Netherlands)

    Martens, J.W.D.; van den Bogert, W.F.; van Silfhout, Arend

    1981-01-01

    The effect of low energy noble gas ion bombardment on the electrical and optical properties of Si(211) surfaces has been investigated by surface conductivity and field effect measurements, ellipsometry and AES. With this combination of techniques, information is obtained concerning the electrical

  3. Particle bombardment and the genetic enhancement of crops: myths and realities

    NARCIS (Netherlands)

    Altpeter, F.; Baisakh, N.; Beachy, R.; Bock, R.; Capell, T.; Christou, P.; Daniell, H.; Datta, K.; Datta, S.; Dix, P.J.; Fauquet, C.; Huang, N.; Kohli, A.; Mooibroek, H.; Nicholson, L.; Nguyen, T.T.; Nugent, G.; Raemakers, C.J.J.M.; Romano, A.; Somers, D.A.; Stoger, E.; Taylor, N.; Visser, R.G.F.

    2005-01-01

    DNA transfer by particle bombardment makes use of physical processes to achieve the transformation of crop plants. There is no dependence on bacteria, so the limitations inherent in organisms such as Agrobacterium tumefaciens do not apply. The absence of biological constraints, at least until DNA

  4. Angular and energy dependence of ion bombardment of Mo/Si multilayers

    DEFF Research Database (Denmark)

    Voorma, H.J.; Louis, E.; Bijkerk, F.

    1997-01-01

    The process of ion bombardment is investigated for the fabrication of Mo/Si multilayer x-ray mirrors using e-beam evaporation. The ion treatment is applied immediately after deposition of each of the Si layers to smoothen the layers by removing an additional thickness of the Si layer. In this study...

  5. Linear and nonlinear effects at low energy ion bombardment of solid xenon

    DEFF Research Database (Denmark)

    Dutkiewicz, L.; Pedrys, R.; Schou, Jørgen

    1996-01-01

    Elastic sputtering of crystalline xenon by 20-750 eV Xe ions has been studied with molecular dynamics. The nonlinear effects are dominant at 250 eV ion bombardment. They result in a partly amorphization of the impact volume as well as in a considerable reduction of the surface binding energy...

  6. Particle bombardment and subcellular protein localization analysis in the aquatic plant Egeria densa

    Directory of Open Access Journals (Sweden)

    Yasuhide Osaki

    2017-09-01

    Full Text Available Particle bombardment is a powerful and relatively easy method for transient expression of genes of interest in plant cells, especially those that are recalcitrant to other transformation methods. This method has facilitated numerous analyses of subcellular localization of fluorescent fusion protein constructs. Particle bombardment delivers genes to the first layer of plant tissue. In leaves of higher plants, epidermal cells are the first cell layer. Many studies have used the epidermal cell layer of onion bulb (Allium cepa as the experimental tissue, because these cells are relatively large. However, onion epidermal cells lack developed plastids (i.e., chloroplasts, thereby precluding subcellular localization analysis of chloroplastic proteins. In this study, we developed a protocol for particle bombardment of the aquatic plant Egeria densa, and showed that it is a useful system for subcellular localization analysis of higher plant proteins. E. densa leaflets contain only two cell layers, and cells in the adaxial layer are sufficiently large for observation. The cells in both layers contain well-developed chloroplasts. We fused fluorescent proteins to conventional plant localization signals for the nucleus, cytosol, mitochondria, peroxisome, and chloroplast, and used particle bombardment to transiently express these fusion constructs in E. densa leaves. The plant subcellular localization signals functioned normally and displayed the expected distributions in transiently transformed E. densa cells, and even chloroplastic structures could be clearly visualized.

  7. Sputtering yields of Ru, Mo, and Si under low energy Ar+ bombardment

    NARCIS (Netherlands)

    Wu, S. M.; van de Kruijs, R.; Zoethout, E.; F. Bijkerk,

    2009-01-01

    Ion sputtering yields for Ru, Mo, and Si under Ar+ ion bombardment in the near-threshold energy range have been studied using an in situ weight-loss method with a Kaufman ion source, Faraday cup, and quartz crystal microbalance. The results are compared to theoretical models. The accuracy of the in

  8. Sputtering yields of Ru, Mo and Si under low energy Ar+ bombardment

    NARCIS (Netherlands)

    Wu, Shiou-Min; van de Kruijs, Robbert Wilhelmus Elisabeth; Zoethout, E.; Zoethout, E.; Bijkerk, Frederik

    2009-01-01

    Ion sputtering yields for Ru, Mo, and Si under Ar+ ion bombardment in the near-threshold energy range have been studied using an in situ weight-loss method with a Kaufman ion source, Faraday cup, and quartz crystal microbalance. The results are compared to theoretical models. The accuracy of the in

  9. Thermal stability of magnetic nanostructures in ion-bombardment-modified exchange-bias systems

    Science.gov (United States)

    Höink, V.; Sacher, M. D.; Schmalhorst, J.; Reiss, G.; Engel, D.; Weis, T.; Ehresmann, A.

    2006-06-01

    In magnetic bilayer systems consisting of a ferromagnet and an antiferromagnet the strength and direction of the exchange bias coupling can be set by ion bombardment in an external magnetic field. Magnetic nanostructures with a laterally varying exchange bias direction can be produced by local ion bombardment (ion bombardment induced magnetic patterning). We have investigated the thermal stability of these magnetic nanostructures by in situ x-ray photoemission electron microscopy while heating the samples above their blocking temperature. The investigations have been done at a 10.4μm×10.4μm large checkered pattern with a minimum size of the magnetic patterns of 800nm×800nm on a field cooled MnIr/CoFe stack and a pattern with 1.6μm wide lines with a periodicity of 5μm on an as-prepared MnIr/Co stack. The temperature dependence of the magnetization pattern can be explained by the temperature dependence of the exchange bias interaction, the exchange interaction energy, and the stray field energy. No substantial change of the thermal stability of magnetic patterns in remanence by the ion bombardment was found.

  10. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  11. Atomic Physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  12. Atom Interferometry for Fundamental Physics and Gravity Measurements in Space

    Science.gov (United States)

    Kohel, James M.

    2012-01-01

    Laser-cooled atoms are used as freefall test masses. The gravitational acceleration on atoms is measured by atom-wave interferometry. The fundamental concept behind atom interferometry is the quantum mechanical particle-wave duality. One can exploit the wave-like nature of atoms to construct an atom interferometer based on matter waves analogous to laser interferometers.

  13. Ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Krüger, Peter; Hofferberth, S.; Haller, E.

    2005-01-01

    Miniaturized potentials near the surface of atom chips can be used as flexible and versatile tools for the manipulation of ultracold atoms on a microscale. The full scope of possibilities is only accessible if atom-surface distances can be reduced to microns. We discuss experiments in this regime...

  14. Nuclear effects in atomic transitions

    CERN Document Server

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects that can be identified in atomic structure data. An introduction to the theory of isotope shifts and hyperfine splitting of atomic spectra is given, together with an overview of the typical experimental techniques used in high-precision atomic spectroscopy. More exotic effects at the borderline between atomic and nuclear physics, such as parity violation in atomic transitions due to the weak interaction, or nuclear polarization and nuclear excitation by electron capture, are also addressed.

  15. Precise determination of the absolute isotopic abundance ratio and the atomic weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer-Cs2Cl+-graphite method.

    Science.gov (United States)

    Wei, Hai-Zhen; Jiang, Shao-Yong; Xiao, Ying-Kai; Wang, Jun; Lu, Hai; Wu, Bin; Wu, He-Pin; Li, Qing; Luo, Chong-Guang

    2012-12-04

    Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of atomic weight of chlorine (A(r)(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667-683; and then, it emphasized that the standard atomic weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396). According to the agreement by CIAAW that an atomic weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396), the absolute isotope ratios and atomic weight of chlorine in standard reference materials (NIST 975, NIST 975a, ISL 354) were accurately determined using the high-precision positive thermal ionization mass spectrometer (PTIMS)-Cs(2)Cl(+)-graphite method. After eliminating the weighing error caused from evaporation by designing a special weighing container and accurately determining the chlorine contents in two highly enriched Na(37)Cl and Na(35)Cl salts by the current constant coulometric titration, one series of gravimetric synthetic mixtures prepared from two highly enriched Na(37)Cl and Na(35)Cl salts was used to calibrate two thermal ionization mass spectrometers in two individual laboratories. The correction factors (i.e., K(37/35) = R(37/35meas)/R(37/35calc)) were obtained from five cycles of iterative calculations on the basis of calculated and determined R((37)Cl/(35)Cl) values in gravimetric synthetic mixtures. The absolute R((37)Cl/(35)Cl) ratios for NIST SRM 975, NIST 975a, and ISL 354 by the precise

  16. Determine Neutron Yield From Beryllium Compounds Bombarding With Alpha Particles

    Directory of Open Access Journals (Sweden)

    Osamah Nawfal Oudah

    2015-04-01

    Full Text Available Abstract The chemical combination of Beryllium used in the amp945n reaction as a target materials. wherefore Beryllium has generally been the material of select when manufacturing a neutron source. Beryllium compounds has a significant impact on the scheme and manufacture of the 238Cm-9Be neutron source. In present work the Beryllium chemical combinations were considered as a producer of neutrons with different percentage of mass and the neutron yields were likewise determined using the outcomes of the ASTAR calculations per unit incident charge. The neutron yields of Beryllium Oxide Beryllium Carbide Beryllium Hydride Beryllium Hydroxide and Beryllium Nitride were calculated as 3.1006e-005 3.0365e-005 2.2866e-005 2.0464e-005 and 3.0386e-005respectively. The results show that the Beryllium Oxide is a suitable material to use in the 238Cm-9Be neutron source.

  17. Erosion of Be and deposition of C and O due to bombardment with C{sup +} and CO{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, W.; Goldstrass, P.; Linsmeier, Ch. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1998-01-01

    The bombardment of Be with 3 and 5 keV C{sup +} and CO{sup +} at normal incidence is investigated experimentally and by computer simulation with the program TRIDYN. The deposited amount of C and O is determined experimentally and found in good agreement with calculated data for C bombardment. Chemical erosion dominates at higher fluences for CO{sup +} bombardment. Calculations are then used to determine the sputter yield of Be at steady state conditions as a function of the plasma edge electron temperature for two C impurity concentrations in the incident D flux, typical for fusion plasmas. The fluence to reach steady state conditions is also investigated. (author)

  18. Successful expression in pollen of various plant species of in vitro synthesized mRNA introduced by particle bombardment.

    Science.gov (United States)

    Tanaka, T; Nishihara, M; Seki, M; Sakamoto, A; Tanaka, K; Irifune, K; Morikawa, H

    1995-05-01

    Gold particles coated with beta-glucuronidase (GUS) mRNA with a 5' cap structure that had been synthesized in vitro were introduced, by use of a pneumatic particle gun, into pollen grains of lily (Lilium longiflorum), freesia (Freesia refracta) and tulip (Tulipa gesneriana). A fluorometric assay for the GUS activity indicated that in vitro synthesized GUS mRNA introduced into these pollen cells by particle bombardment was successfully expressed. GUS activity in extracts of the bombarded lily pollen became detectable fluorometrically within 30 min after bombardment, peaked at 6 h, then gradually decreased. This activity changed as a function of the developmental stage of the pollen cell of lily.

  19. Direct evidence for a thermal effect of Ar/sup +/ ion bombardment in a conventional sputtering mode

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, F.; Fujimoto, Y.

    1986-03-01

    Evidence is presented that the Ar/sup +/ ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 /sup 0/C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar/sup +/ ions, proving that the needle tips were melted by impacting Ar/sup +/ ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment.

  20. Initialization of unidirectional anisotropy in a ferromagnet-antiferromagnet bilayer by keV-He ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Engel, D. [Fachbereich Physik, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Str. D-67663 Kaiserslautern (Germany)]. E-mail: wengel@rhrk.uni-kl.de; Ehresmann, A. [Fachbereich Physik, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Str. D-67663 Kaiserslautern (Germany); Schmalhorst, J. [Fakultaet fuer Physik, Universitaet Bielefeld, D-33501 Bielefeld (Germany); Sacher, M. [Fakultaet fuer Physik, Universitaet Bielefeld, D-33501 Bielefeld (Germany); Hoeink, V. [Fakultaet fuer Physik, Universitaet Bielefeld, D-33501 Bielefeld (Germany); Reiss, G. [Fakultaet fuer Physik, Universitaet Bielefeld, D-33501 Bielefeld (Germany)

    2005-06-15

    A polycrystalline Cu/Ni{sub 80}Fe{sub 20}/Mn{sub 83}Ir{sub 17}/Co/AlO{sub x} ferromagnet-antiferromagnet layer system grown without applying an external magnetic field shows no unidirectional anisotropy in the as-prepared state. After 10keV-He ion bombardment in an external in-plane magnetic field, a clear unidirectional anisotropy collinear to the magnetic field direction during bombardment is observed, indicating that ion bombardment can be used for this system to initialize the unidirectional exchange anisotropy. The magnetization reversal processes for various ion doses are discussed, based on longitudinal magnetooptical Kerr-effect measurements.

  1. Characterization of national food agency shrimp and plaice reference materials for trace elements and arsenic species by atomic and mass spectrometric techniques

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pedersen, Gitte Alsing; McLaren, J. W.

    1997-01-01

    , drying, milling and sieving to collect the fraction of particles less than 150 mu m in sizer In this fraction the trace elements were homogeneously distributed using a 400 mg sample intake for analysis, The total track element concentrations were determined by graphite furnace and cold vapour atomic...

  2. Doping monolayer graphene with single atom substitutions

    KAUST Repository

    Wang, Hongtao

    2012-01-11

    Functionalized graphene has been extensively studied with the aim of tailoring properties for gas sensors, superconductors, supercapacitors, nanoelectronics, and spintronics. A bottleneck is the capability to control the carrier type and density by doping. We demonstrate that a two-step process is an efficient way to dope graphene: create vacancies by high-energy atom/ion bombardment and fill these vacancies with desired dopants. Different elements (Pt, Co, and In) have been successfully doped in the single-atom form. The high binding energy of the metal-vacancy complex ensures its stability and is consistent with in situ observation by an aberration-corrected and monochromated transmission electron microscope. © 2011 American Chemical Society.

  3. Influence of the inert and active ion bombardment on structure of the transition metal thin films

    CERN Document Server

    Blazhevich, S; Martynov, I; Neklyudov, I

    2002-01-01

    The results of the experimental research of the inert (He, Ne, Ar, Kr, Xe) and active (O, N) ion impact on the transition metal structure are presented. Thin high-purity (99.999 at.%) films of nickel, chrome and iron were used in the experiment. The bombardment was realized under room temperature at high vacuum (P<1x10 sup - sup 7 Pa) by a separated ion beam of 10-10 sup 3 keV. As a main result of the experiment, the full absence of crystal matrix changes was ascertained for all the transition metals irradiated by inert gas ions. The chemical nature of the crystal structure changes observed in transition metals being under active ion bombardment was found out too.

  4. Rehabilitation and construction of bridges damaged in NATo-bombardment of SR Yugoslavia in 1999

    Directory of Open Access Journals (Sweden)

    Vlajić Ljubomir M.

    2014-01-01

    Full Text Available Structural engineers from Serbia and nearby countries have long tradition in area of design and construction of bridges. Beside ancient stone bridges from the past centuries, in the second half of the XX century, significant professional and science level in all areas of bridge construction have been achieved. Many of projects from that time have become famous all around the globe and were object of pride for everyone included in realization of those. Regretfully, during seventy eight days, in the period from 24th March till the 10th July 1999, in NATO bombardment of SR Yugoslavia, 44 road, 17 railway and one road railway bridge have been totally or partially destroyed. In this article have been described structural damages, rehabilitation and construction, with short description of characteristic cases of bridges, which have been object of bombardment.

  5. Adsorption Site of Gas Molecules on Defective Armchair Graphene Nanoribbon Formed Through Ion Bombardment

    Science.gov (United States)

    Auzar, Zuriana; Johari, Zaharah; Sakina, S. H.; Alias, N. Ezaila

    2018-02-01

    High sensitivity and selectivity is desired in sensing devices. The aim of this study is to investigate the use of the ion bombardment process in creating a defect on graphene nanoribbons (GNR), which significantly affects sensing properties, in particular adsorption energy, charge transfer and sensitivity. A process has been developed to form the defect on the GNR surface using molecular dynamic (MD) with a reactive force field with nitrogen ion. The sensing properties were calculated using the extended Huckel theory when oxygen (O2) and ammonia (NH3) molecules are exposed to different areas on the defective site. Through simulation, it was found that the ion bombardment process formed various types of defects on the GNR surface. Most notably, molecules adsorbed on the ripple area considerably improve the sensitivity by more than 50%. This indicates that the defect on the armchair graphene nanoribbon (AGNR) surface can be a method to enhance graphene-based sensing performance.

  6. Genetic transformation of Platymonas ( Tetraselmis) subcordiformis (Prasinophyceae, Chlorophyta) using particle bombardment and glass-bead agitation

    Science.gov (United States)

    Cui, Yulin; Jiang, Peng; Wang, Jinfeng; Li, Fuchao; Chen, Yingjie; Zheng, Guoting; Qin, Song

    2012-05-01

    Platymonas ( Tetraselmis) subcordiformis is a unicellular marine green alga. It was found to be very sensitive to the herbicide Basta through a sensitivity test indicating it could be employed as a selective agent. The bar gene is a practicable and selectable marker gene. The vector containing the expression cassette of the bar gene was transferred to P. subcordiformis by both particle bombardment and glass-bead agitation and transformants were then selected using Basta. Finally, Southern blotting analysis indicated that the bar gene had been successfully integrated into the nuclear genome of P. subcordiformis using both of the transgenic techniques, with the transformation efficiency of the glass-bead method being slightly higher than that of particle bombardment. This is the first report on stable transformation of P. subcordiformis, and will improve fundamental research and enlarge application of this alga.

  7. Films deposited from reactive sputtering of aluminum acetylacetonate under low energy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, Felipe Augusto Darriba; Prado, Eduardo Silva; Cruz, Nilson Cristino da; Rangel, Elidiane Cipriano, E-mail: elidiane@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Caseli, Luciano [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas; Silva, Tiago Fiorini da; Tabacniks, Manfredo Harri [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Films were deposited from aluminum acetylacetonate (Al(acac)3 ) using a methodology involving reactive sputtering and low energy ion bombardment. The plasma was generated by the application of radiofrequency power to the powder containing electrode and simultaneously, negative pulses were supplied to the electrode where the substrates were attached. It was investigated the effect of the duty cycle of the pulses (Δ) on the properties of the coatings. Association of ion bombardment to the deposition process increased film thickness, structure reticulation and organic content. Ions from the deposition environment were implanted at the film-air interface or underneath it. Morphology and topography were altered depending on Δ. Considering the enhancement of Δ, it affected the flux of ions reaching the depositing interface and then the deposition rate, H content, crosslinking degree and surface microstructure. Alumina groups were detected in the infrared spectra, whereas the precipitation of amorphous alumina was confirmed by X-ray diffraction. (author)

  8. Atomic physics

    CERN Document Server

    Born, Max

    1969-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  9. Early Atomism

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/reso/015/10/0905-0925. Keywords. Atomic theory; Avogadro's hypothesis; atomic weights; periodic table; valence; molecular weights; molecular formula; isomerism. Author Affiliations. S Ramasesha1. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, ...

  10. Foil analysis of 1.5-GeV proton bombardment of a mercury target

    CERN Document Server

    Charlton, L A; Glasgow, D C; Gabriel, T A

    1999-01-01

    The number of reactant nuclei in a series of foils surrounding a container of mercury that has been bombarded by 1.5-GeV protons is calculated and compared with experimental measurements. This procedure is done to aid in the validation of the mercury cross sections used in the design studies of the Spallation Neutron Source (SNS). It is found that the calculations match the measurements to within the uncertainties inherent in the analysis.

  11. Highly ordered nanoscale patterns produced by masked ion bombardment of a moving solid surface

    Science.gov (United States)

    Gelfand, Martin P.; Bradley, R. Mark

    2012-09-01

    We introduce a fabrication method in which a mask with a long, narrow slit is placed between the source of an ion beam and the surface of a solid moving with constant speed. Numerical simulations reveal the method can generate surface ripples and arrays of nanoholes that are virtually defect free. In contrast, the patterns produced by ion bombardment with a broad, unmasked beam are typically rife with defects.

  12. A low-voltage, high-current, ion-bombardment source using magnetron principles

    Energy Technology Data Exchange (ETDEWEB)

    Ja' fer, H.A.; Howson, R.P. (Loughborough Univ of Technology (United Kingdom). Dept. of Physics)

    The operation of an unbalanced magnetron under conditions using extra electron injection is shown to be a source of plasma beam which can give a substrate a self-bias of between 25 and 100 V, and allow total ion-currents of over one ampere to be drawn to a target. The use of the device to give low-energy, ion-bombardment of a growing films and to form a dense plasma source for low voltage sputtering is reported. (Author).

  13. A review of electron bombardment thruster systems/spacecraft field and particle interfaces

    Science.gov (United States)

    Byers, D. C.

    1978-01-01

    This paper collates and summarizes information on the field and particle interfaces of electron bombardment ion thruster systems. Major areas discussed are the nonpropellant particles, neutral propellant, ion beam, low energy plasma, and fields. Spacecraft functions and subsystems reviewed are solar arrays, thermal control systems, optical sensors, communications, science, structures and materials, and potential control. An appendix is included to facilitate identification of specific interaction areas.

  14. Bohmian picture of Rydberg atoms

    Indian Academy of Sciences (India)

    Abstract. Unlike the previous theoretical results based on standard quantum mechanics that established the nearly elliptical shapes for the centre-of-mass motion in Rydberg atoms using numerical simulations, we show analytically that the Bohmian trajectories in Rydberg atoms are nearly elliptical.

  15. Importance of ion bombardment during coverage of Au nanoparticles on their structural features and optical response

    Energy Technology Data Exchange (ETDEWEB)

    Resta, V.; Peláez, R. J.; Afonso, C. N. [Laser Processing Group, Instituto de Óptica, CSIC, Serrano 121, E-28006 Madrid (Spain)

    2014-03-28

    This work studies the changes in the optical response and morphological features of 6 ± 1 nm diameter Au nanoparticles (NPs) when covered by a layer of a-Al{sub 2}O{sub 3} by pulsed laser deposition (PLD). The laser fluence used for ablating the Al{sub 2}O{sub 3} target is varied in order to modify the kinetic energy (KE) of the species bombarding the NPs during their coverage. When the ion KE < 200 eV, the structural features and optical properties of the NPs are close to those of uncovered ones. Otherwise, a shift to the blue and a strong damping of the surface plasmon resonance is observed as fluence is increased. There are two processes responsible for these changes, both related to aluminum ions arriving to the substrate during the coverage process, i.e., sputtering of the metal and implantation of aluminum species in the metal. Both processes have been simulated using standard models for ion bombardment, the calculated effective implanted depths allow explaining the observed changes in the optical response, and the use of a size-dependent sputtering coefficient for the Au NPs predicts the experimental sputtering fractions. In spite of the work is based on PLD, the concepts investigated and conclusions can straightforwardly be extrapolated to other physical vapor deposition techniques or processes involving ion bombardment of metal NPs by ions having KE > 200 eV.

  16. Segregation under low-energy oxygen bombardment in the near-surface region

    Science.gov (United States)

    Tada, Y.; Suzuki, K.; Kataoka, Y.

    2008-12-01

    We found that a transient region of SIMS profiles was suppressed to less than the native oxide in silicon, with O 2+ bombardment energy of less than 0.2 keV under an incident angle of 0° with respect to the surface normal without oxygen flooding. However, gallium segregated significantly due to oxidation caused by O 2+ bombardment in this condition. We also found that the segregation decreased as the incident angle increased, and that it disappeared at the angle of around 40°, which was verified by comparing SIMS profiles with the HR-RBS profile. These results suggested that the angle of around 40° was the critical angle to prevent segregation. The transient region was almost the same at angles of 0-40°. Therefore, we consider that the energy of 0.2 keV at the angle of around 40° under O 2+ bombardment without oxygen flooding is the optimum SIMS condition for depth profiling in the near-surface region. On the other hand, the profile shift of arsenic depending on the angle was quite different as compared with gallium, but the shift was a minimum at the same critical angle. We expect that more accurate profiles for other impurities can be obtained using this SIMS condition.

  17. Oligosaccharide sequence determination using B/E linked field scanning or tandem mass spectrometry of phosphatidylethanolamine derivatives.

    Science.gov (United States)

    Chai, W; Cashmore, G C; Stoll, M S; Gaskell, S J; Orkiszewski, R S; Lawson, A M

    1991-05-01

    Product ion mass spectral data of [M + H]+ ions of oligosaccharides, mainly tetra- and pentasaccharides, as their dipalmitoyl phosphatidylethanolamine derivatives were obtained using both liquid secondary ion mass spectrometry with B/E linked scanning and fast atom bombardment ionization with collision-induced dissociation/tandem mass spectrometry. Both methods give similar positive product ion spectra of equivalent high sensitivity (detection limits of approximately 50 pmol) that principally contain glycosidic cleavage ions retaining the reducing end of the molecule from which monosaccharide sequence can be deduced. A series of ions from fission of the phosphate ester bond together with glycosidic cleavage are present in the tandem mass spectra and B/E linked scan spectra when helium collision gas is used. Monosaccharide linkage position of isomeric molecules is reflected in the intensity of glycosidic fragmentation, without retention of the oxygen atom, with decreasing cleavage in the order 1-3 greater than 1-4 greater than 1-6 linkage. Fucose and N-acetylhexosamines show an increased degree of fragmentation over hexose sugars. The application of product ion spectra of derivatized oligosaccharides is demonstrated for characterizing mixed samples and also the acquisition of spectra directly from the silica surface of high-performance thin-layer chromatography plates.

  18. Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD

    Science.gov (United States)

    Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

    2017-11-01

    In order to confirm the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar+ ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar+ ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar+ ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar+ ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar+ ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar+ ion state. As for vertically oriented few-layer graphene (VFG), Ar+ ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar+ ion bombardment, and these special NCMs are promising in many fields.

  19. Atomic interferometry; Interferometrie atomique

    Energy Technology Data Exchange (ETDEWEB)

    Baudon, J.; Robert, J. [Paris-13 Univ., 93 - Saint-Denis (France)

    2004-07-01

    Since the theoretical works of L. De Broglie (1924) and the famous experiment of Davisson and Germer (1927), we know that a wave is linked with any particle of mass m by the relation {lambda} = h/(mv), where {lambda} is the wavelength, v the particle velocity and h is the Planck constant. The basic principle of the interferometry of any material particle, atom, molecule or aggregate is simple: using a simple incident wave, several mutually consistent waves (with well-defined relative phases) are generated and controllable phase-shifts are introduced between them in order to generate a wave which is the sum of the previous waves. An interference figure is obtained which consists in a succession of dark and bright fringes. The atomic interferometry is based on the same principle but involves different techniques, different wave equations, but also different beams, sources and correlations which are described in this book. Because of the small possible wavelengths and the wide range of possible atomic interactions, atomic interferometers can be used in many domains from the sub-micron lithography to the construction of sensors like: inertial sensors, gravity-meters, accelerometers, gyro-meters etc. The first chapter is a preliminary study of the space and time diffraction of atoms. The next chapters is devoted to the description of slit, light separation and polarization interferometers, and the last chapter treats of the properties of Bose-Einstein condensates which are interesting in atomic interferometry. (J.S.)

  20. Mass energy-absorption coefficients and average atomic energy-absorption cross-sections for amino acids in the energy range 0.122-1.330 MeV

    Energy Technology Data Exchange (ETDEWEB)

    More, Chaitali V., E-mail: chaitalimore89@gmail.com; Lokhande, Rajkumar M.; Pawar, Pravina P., E-mail: pravinapawar4@gmail.com [Department of physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India)

    2016-05-06

    Mass attenuation coefficients of amino acids such as n-acetyl-l-tryptophan, n-acetyl-l-tyrosine and d-tryptophan were measured in the energy range 0.122-1.330 MeV. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The measured attenuation coefficient values were then used to determine the mass energy-absorption coefficients (σ{sub a,en}) and average atomic energy-absorption cross sections (μ{sub en}/ρ) of the amino acids. Theoretical values were calculated based on XCOM data. Theoretical and experimental values are found to be in good agreement.

  1. Determination of Cd, Co, Cu, Mn, Ni, Pb, and Zn by Inductively Coupled Plasma Mass Spectroscopy or Flame Atomic Absorption Spectrometry after On-line Preconcentration and Solvent Extraction by Flow Injection System

    Science.gov (United States)

    Bortoli; Gerotto; Marchiori; Mariconti; Palonta; Troncon

    1996-11-01

    The concentrations of Cd, Co, Cu, Mn, Ni, Pb, and Zn in natural and sea waters are too low to be directly determined with by flame atomic absorption spectrometry (FAAS) or graphite furnace atomic absorption spectrometry (GFAAS). Specific sample preparations are requested that make possible the determination of these analytes by preconcentration or extraction. These techniques are affected by severe problems of sample contamination. In this work Cd, Co, Cu, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS) or by atomic absorption spectrometry, in fresh and seawater samples, after on-line preconcentration and following solvent elution with a flow injection system. Bonded silica with octadecyl functional group C18, packed in a microcolumn of 100-μl capacity, was used to collect diethyldithiocarbamate complexes of the heavy metals in aqueous solutions. The metals are complexed with a chelating agent, adsorbed on the C18 column, and eluted with methanol directly in the flow injection system. The methanolic stream can be addressed to FAAS for direct determination of Cu, Ni, and Zn, or collected in a vial for successive analysis by GFAAS. The eluted samples can be also dried in a vacuum container and restored to a little volume with concentrated HNO3 and Milli-Q water for analysis by ICP-MS or GFAAS.

  2. Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

    NARCIS (Netherlands)

    Dolgov, A.; Dolgov, A.; Lopaev, D.; Lee, Christopher James; Zoethout, E.; Zoethout, E.; Medvedev, Viacheslav; Yakushev, O.; Bijkerk, Frederik

    2015-01-01

    Molecular contamination of a grazing incidence collector for extreme ultraviolet (EUV) lithography was experimentally studied. A carbon film was found to have grown under irradiation from a pulsed tin plasma discharge. Our studies show that the film is chemically inert and has characteristics that

  3. Spectrometre de masse a ionisation Penning selective: Elimination des corrections necessaires a la determination du rapport isotopique de l'hydrogene

    Science.gov (United States)

    Letarte, Sylvain

    Dans le but d'ameliorer la precision avec laquelle le rapport isotopique de l'hydrogene peut etre determine, un spectrometre de masse a ionisation Penning a ete construit pour provoquer l'ionisation selective de l'hydrogene moleculaire et de l'hydrure de deuterium a partir d'un melange gazeux. L'utilisation d'atomes dans des etats d'excitation metastable s'est averee une solution adequate pour reponde a cette attente. L'emploi de l'helium, a l'interieur d'une source d'atomes metastables construit specifiquement pour ce travail, ne permet pas d'obtenir un spectre de masse compose uniquement des deux molecules d'interet. L'ionisation de ces dernieres provient de deux processus distincts, soient l'ionisation Penning et l'ionisation par bombardement electronique. Contrairement a l'helium, il a ete demontre que le neon metastable est un candidat ideal pour produire l'ionisation selective de type Penning. Le nombre d'ions produits est directement proportionnel au courant de la decharge electrique et de la pression d'operation de la source d'atomes metastables. Ces resultats demontrent le potentiel d'un tel spectrometre de masse pour ameliorer la precision a laquelle le rapport isotopique peut etre determine comparativement aux autres techniques existantes.

  4. N(50) Crater Retention Ages for an Expanded Inventory of Lunar Basins: Evidence for an Early Heavy Bombardment and a Late Heavy Bombardment?

    Science.gov (United States)

    Frey, Herbert; Burgess, Emily

    2012-01-01

    LOLA topography and LOLA-derived crustal thickness data provide evidence for a population of impact basins on the Moon that is likely a factor 2 larger than the classical lists based on photogeology. Frey (2012) determined N(50) crater retention ages (CRAs) for 83 candidate basins > 300 km in diameter by counting LOLA-identified craters superimposed over the whole area of the basins. For some basins identified in topography or model crustal thickness it is not possible to unambiguously identify the crater rim as is traditionally done. Also, Quasi-Circular Depressions (QCDs) > 50 km in diameter are recognizable in the mare-filled centers of many basins. Even though these are not apparent in image data, they likely represent buried impact craters superimposed on the basin floor prior to mare infilling and so should be counted in determining the age of the basin. Including these as well as the entire area of the basins improves the statistics, though the error bars are still large when using only craters > 50 km in diameter. The distribution of N(50) CRAs had two distinct peaks which did not depend on whether the basins were named (based on photogeology) or recognized first in topography or crustal thickness data. It also did not depend on basin diameters (both larger and smaller basins made up both peaks) and both peaks persisted even when weaker candidates were excluded. Burgess (2012, unpublished data) redid the counts for 85 basins but improved on the earlier effort by adjusting the counting area where basins overlap. The two peak distribution of N(50) ages was confirmed, with a younger peak at N(50) 40-50 and an older peak at N(50) 80-90 (craters > 50 km diameter per million square km). We suggest this could represent two distinct populations of impactors on the Moon: one producing an Early Heavy Bombardment (EHB) that predates Nectaris and the second responsible for the more widely recognized Late Heavy Bombardment (LHB).

  5. Speciation of four selenium compounds using high performance liquid chromatography with on-line detection by inductively coupled plasma mass spectrometry or flame atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Pedersen, Gitte Alsing; Larsen, Erik Huusfeldt

    1997-01-01

    An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column was used as the stationary phase in combination...... of 1300 W. The limit of detection achieved under these conditions was 1 mu g L-1 (100 mu L injections). The HPLC-ICP-MS system was used for selenium speciation of selenite and selenate in aqueous solutions during a BCR certification exercise and for selenium speciation in the certified reference material...

  6. SPITZER EVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN {eta} CORVI At {approx}1 Gyr

    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Morlok, A. [Department of Earth and Planetary Sciences, The Open University, Milton-Keynes (United Kingdom); Watson, D. M.; Manoj, P.; Sheehan, P. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Currie, T. M. [NASA-GSFC, Code 667, Greenbelt, MD 20771 (United States); Thebault, P. [Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Sitko, M. L., E-mail: carey.lisse@jhuapl.edu, E-mail: wyatt@ast.cam.ac.uk, E-mail: cchen@stsci.edu, E-mail: a.morlok@open.ac.uk, E-mail: dmw@pas.rochester.edu, E-mail: manoj@pas.rochester.edu, E-mail: psheeha2@mail.rochester.edu, E-mail: thayne.m.currie@nasa.gov, E-mail: philippe.thebault@obspm.fr, E-mail: sitko@spacescience.org [Space Science Institute, 475 Walnut Street, Suite 205, Boulder, CO 80301 (United States)

    2012-03-10

    We have analyzed Spitzer and NASA/IRTF 2-35 {mu}m spectra of the warm, {approx}350 K circumstellar dust around the nearby MS star {eta} Corvi (F2V, 1.4 {+-} 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at {approx}3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high-temperature carbonaceous phases. At least 9 Multiplication-Sign 10{sup 18} kg of 0.1-100 {mu}m warm dust is present in a collisional equilibrium distribution with dn/da {approx} a{sup -3.5}, the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm{sup 3} density and similar to recent estimates of the mass delivered to the Earth at 0.6-0.8 Gyr during the late-heavy bombardment. We conclude that the parent body was a Kuiper Belt body or bodies which captured a large amount of early primitive material in the first megayears of the system's lifetime and preserved it in deep freeze at {approx}150 AU. At {approx}1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 km s{sup -1} with a rocky planetary body of mass {<=}M{sub Earth} at {approx}3 AU, delivering large amounts of water (>0.1% of M{sub Earth'sOceans}) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.

  7. Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography-inductively coupled-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry

    Science.gov (United States)

    The formation of methylarsonous acid (MAsIII) and dimethylarsinous acid (DMAsIII) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass ...

  8. Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Lynelle; Zhou, Jia; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid

    2008-12-05

    A new mass spectrometry surface imaging method is presented in which ion-sputtered neutrals are postionized by wavelength-tunable vacuum ultraviolet (VUV) light from a synchrotron source. Mass spectra and signal counts of the photoionized neutrals from GaAs (100) and Au are compared to those of the secondary ions. While clusters larger than dimers are more efficiently detected as secondary ions, certain species, such as As2, Au and Au2, are more efficiently detected through the neutral channel. Continuously tuning the photon wavelength allows photoionization efficiency (PIE) curves to be obtained for sputtered Asm (m=1,2) and Aun (n=1-4). From the observed ionization thresholds, sputtered neutral As and Au show no clear evidence of electronic excitation, while neutral clusters have photoionization onsets shifted to lower energies by ~;;0.3 eV. These shifts are attributed to unresolved vibrational and rotational excitations. High-spatial resolution chemical imaging with synchrotron VUV postionization is demonstrated at two different photon energies using a copper TEM grid embedded in indium. The resulting images are used to illustrate the use of tunable VUV light for verifying mass peak assignments by exploiting the unique wavelength-dependent PIE of each sputtered neutral species. This capability is valuable for identifying compounds when imaging chemically complex systems with mass spectrometry-based techniques.

  9. Theory of Nonlinear Generation of X-Radiation in a Crystal Subjected to Intense Electron Bombardment.

    Science.gov (United States)

    1980-11-01

    initially excited atom and unexcited atoms respectively, a(t) is the probability amplitude that the initially excited atom is excited at time t, all...other atoms are in their ground state and there are no photons in the radiation field; b is the probability amplitude that there is one photon with

  10. Cosmic Bombardment IV: Averting catastrophe in the here-and-now

    Energy Technology Data Exchange (ETDEWEB)

    Wood, L.; Hyde, R.; Ishikawa, M.; Ledebuhr, A.

    1994-09-23

    At the present time, it is at least arguable that large-scale cosmic bombardment has been a major driver of the evolution of the terrestrialbiosphere. The fundamental motivation of the present paper is the (high) likelihood that the advent and rise of the human species hasn`t coincided with the cessation of soft and hard collisions in the Asteroid Belt or in the Oort Cloud, and that we will either stop the cosmic bombardment or it will eventually stop us. In the foregoing, briefly reviewed the prospects for active planetary defenses against cosmic bombardment in the very near-term, employing only technologies which exist now and could be brought-to-bear in a defensive system on a one-decade time-scale. We sketch various means and mechanisms from a physicist`s viewpoint by which such defensive systems might detect threat objects, launch interdiction machinery toward them and operate such machinery in their vicinity to alternately deflect, disperse or vaporize objects in the 0.1-10 km-diameter range, the ones whose size and population constitute the greatest threats to our biosphere. We conclude that active defenses of all types are readily feasible against 0.1 kmdiameter incoming cosmic bomblets and that even complete vaporization-class defenses are feasible against 1 km-diameter class objects of all compositions. When facing Great Extinctors of up to 10 km diameter, the feasible defensive methods depend upon the object`s size and composition. Dispersion defenses are feasible against all threat-classes, as are deflection approaches for bomblets up to {approximately} 10 km diameter; vaporization-level protection is, however, available only against dirty snowballs` of the {approximately} 1--2 km diameter class. Great Extinctors of sizes significantly greater than 10 km diameter challenge contemporary human technology ever more severely; fortunately, they appear to be rare on the several Aeon time-scales over which Sol will shift its spectral class.

  11. Five lowest S1 states of the Be atom calculated with a finite-nuclear-mass approach and with relativistic and QED corrections

    Science.gov (United States)

    Stanke, Monika; Komasa, Jacek; Bubin, Sergiy; Adamowicz, Ludwik

    2009-08-01

    We have performed very accurate quantum mechanical calculations of the five lowest S states of the beryllium atom. In the nonrelativistic part of the calculations we used the variational method and we explicitly included the nuclear motion in the Schrödinger equation. The nonrelativistic wave functions of the five states were expanded in terms of explicitly correlated Gaussian functions. These wave functions were used to calculate the leading α2 relativistic correction ( α is the fine structure constant) and the α3 quantum electrodynamics (QED) correction. We also estimated the α4 QED correction by calculating its dominant component. A comparison of the experimental transition frequencies with the frequencies obtained based on the energies calculated in this work shows an excellent agreement.

  12. Microprojectile Bombardment Transformation of Date Palm Using the Insecticidal Cholesterol Oxidase (ChoA) Gene.

    Science.gov (United States)

    Allam, Mai A; Saker, Mahmoud M

    2017-01-01

    The overall objective of this work is to optimize the transformation system for date palm as a first step toward production of date palm clones resistant to noxious pests. A construct harboring the cholesterol oxidase (ChoA) gene, which renders plant resistance against insect attack, is introduced into embryogenic date palm callus using the PDS-1000/He particle bombardment system. The process involves the establishment of embryogenic callus cultures as well as immature embryo-derived microcalli that are used as target tissues for shooting and optimization of transformation conditions. This chapter in addition explains molecular and histochemical assays conducted to confirm gene integration and expression.

  13. Computer simulation of chemical erosion of graphite due to hydrogen ion bombardment

    CERN Document Server

    Liang, J H; Roth, J; Eckstein, W

    2003-01-01

    Chemical erosion of graphite due to hydrogen ion bombardment has been investigated theoretically by applying a model of chemical erosion to the TRIDYN code. The model involves the formation of methane at the end of the ion track as well as the kinetic emission of hydrocarbons from the target surface. Model calculations were performed for ion energies ranging from 10 to 1000 eV and at target temperatures ranging from 300 to 900 K. Good agreement between calculated and measured erosion yields is obtained.

  14. Reducing Back-Bombardment Effect Using Thermionic Cathode in IAE RF Gun

    CERN Document Server

    Kii, Toshiteru; Masuda, Kai; Murakami, Shio; Ohgaki, Hideaki; Yamazaki, Tetsuo; Yoshikawa, Kiyoshi; Zen, Heishun

    2004-01-01

    We have numerically studied on improvement of electron beam macro-pulse properties from thermionic RF gun [1,2]. Beam properties, such as energy spectrum, macro-pulse duration and emittance were measured with a 2 mm diameter slim thermionic dispenser cathode. Effect of the transverse magnetic field to reduce back-streaming electrons to these properties was studied experimentally. Comparison with measured and numerical results will be discussed. Effect of a non-flat RF input to compensate a decreasing beam energy during macropulse due to a back-bombardment effect will be also presented.

  15. Chromium recoil implantation into SAE 1020 steel by nitrogen ion bombardment

    OpenAIRE

    Gomes, G. F.; Ueda, M.; Reuther, H.; Richter, E.; Beloto, A. F.

    2004-01-01

    SAE 1020 is a widely used plain carbon steel, as mortar reinforcement in buildings and small machine parts. But aside from good mechanical properties, its surface suffer from severe corrosion and high wear rate, due to modest hardness. Chromium (Cr) in excess of 12% in Fe alloys renders them resistant to several corrosive attacks. So we tried to introduce Cr in such amounts into the surface of that steel. Cr films were deposited by electron beam on SAE 1020 steel. Bombarding the Cr film eithe...

  16. Surface layer evolution caused by the bombardment with ionized metal vapor

    Energy Technology Data Exchange (ETDEWEB)

    Döbeli, M., E-mail: doebeli@phys.ethz.ch [Ion Beam Physics, ETH Zurich, Schafmattstrasse 20, CH-8093 Zurich (Switzerland); Dommann, A.; Maeder, X.; Neels, A. [Centre Suisse d’Electronique et de Microtechnique CSEM SA, Rue Jaquet-Droz 1, CH-2002 Neuchâtel (Switzerland); Passerone, D. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Rudigier, H. [OC Oerlikon Balzers AG, Iramali 18, LI-9496 Balzers (Liechtenstein); Scopece, D. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Widrig, B.; Ramm, J. [OC Oerlikon Balzers AG, Iramali 18, LI-9496 Balzers (Liechtenstein)

    2014-08-01

    The evolution of the composition of tungsten carbide and silicon surfaces initiated by the bombardment with Zr and Cr ions has been investigated as a function of the substrate bias voltage. Surface composition profiles were measured by Rutherford backscattering and have been compared with the results obtained by the TRIDYN simulation program. It is found that the general dependence of film thickness on substrate bias is satisfactorily reproduced by this model. Deviations between experiment and simulation are attributed to possible partial oxidation of the surface or uncertainties in the charge state distribution of metal ions. The results confirm that TRIDYN facilitates the predictability of the nucleation of metallic vapor at substrate surfaces.

  17. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  18. Atomic Power

    African Journals Online (AJOL)

    Atomic Power. By Denis Taylor: Dr. Taylor was formerly Chief UNESCO Advisor at the University. College, Nairobi, Kenya and is now Professor of Electrical Engineering in the Uni- versity of ... method of producing radioactive isotopes, which are materials .... the sealing and the pressure balancing, all can be carried out ...

  19. Linear Atom Guides: Guiding Rydberg Atoms and Progress Toward an Atom Laser

    Science.gov (United States)

    Traxler, Mallory A.

    In this thesis, I explore a variety of experiments within linear, two-wire, magnetic atom guides. Experiments include guiding of Rydberg atoms; transferring between states while keeping the atoms contained within the guide; and designing, constructing, and testing a new experimental apparatus. The ultimate goal of the atom guiding experiments is to develop a continuous atom laser. The guiding of 87Rb 59D5/2 Rydberg atoms is demonstrated. The evolution of the atoms is driven by the combined effects of dipole forces acting on the center-of-mass degree of freedom as well as internal-state transitions. Time delayed microwave and state-selective field ionization, along with ion detection, are used to investigate the evolution of the internal-state distribution as well as the Rydberg atom motion while traversing the guide. The observed decay time of the guided-atom signal is about five times that of the initial state. A population transfer between Rydberg states contributes to this lengthened lifetime, and also broadens the observed field ionization spectrum. The population transfer is attributed to thermal transitions and, to a lesser extent, initial state-mixing due to Rydberg-Rydberg collisions. Characteristic signatures in ion time-of-flight signals and spatially resolved images of ion distributions, which result from the coupled internal-state and center-of-mass dynamics, are discussed. Some groups have used a scheme to make BECs where atoms are optically pumped from one reservoir trap to a final state trap, irreversibly transferring those atoms from one trap to the other. In this context, transfer from one guided ground state to another is studied. In our setup, before the atoms enter the guide, they are pumped into the | F = 1, mF = --1> state. Using two repumpers, one tuned to the F = 1 → F' = 0 transition (R10) and the other tuned to the F = 1 → F' = 2 transition (R12), the atoms are pumped between these guided states. Magnetic reflections within the guide

  20. Immediate fabrication of flower-like graphene oxide by ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Junjie [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zhang, Yuanyuan; Zhang, Guilong [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xiong, Shiquan [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Pei, Renjun, E-mail: rjpei2011@sinano.ac.cn [Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Cai, Dongqing, E-mail: dqcai@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-12-01

    Graphical abstract: - Highlights: • Ion beam bombardment (IBB) could modify the microstructure of graphene oxide (GO). • IBB could transform a compact multi-layered GO to a few-layered flower-like GO. • IBB could effectively improve the dispersion and the related properties of GO. • The main mechanism was proposed to be the etching and charge effects of IBB. - Abstract: An effective and convenient method using ion beam bombardment (IBB) for separating a multi-layered compact graphene oxide (GO) piece into several small few-layered loose pieces was developed, and it was found that those small GO pieces had formed a flower-like structure. Therein, the main mechanism was proposed to be the etching and charge effects of IBB. This work could provide a facile and promising approach for improving the dispersion and the related properties of GO. Furthermore, X-ray diffraction and Raman spectrum determinations demonstrated that, with the increasing fluence, IBB could effectively decrease the chemical groups in the layers of GO, resulting in the decrease of the layer distance.

  1. Angular distribution of GaAs sputtered under oblique Cs{sup +} bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Verdeil, C. [Department ' Science and Analysis of Materials' (SAM), Centre de Recherche Public - Gabriel Lippmann, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Wirtz, T. [Department ' Science and Analysis of Materials' (SAM), Centre de Recherche Public - Gabriel Lippmann, 41 rue du Brill, L-4422 Belvaux (Luxembourg)], E-mail: wirtz@lippmann.lu; Scherrer, H. [Laboratoire de Physique des Materiaux, Ecole des Mines, Parc de Saurupt, F-54042 Nancy Cedex (France)

    2009-08-15

    The angular distribution of Ga and As sputtered from Gallium Arsenide (1 0 0) by a Cs{sup +} ion beam was experimentally measured through a collector technique allowing modifications of the energy and incidence angle of the ion beam. The impact energy was varied in the range of 2-10 keV and the angle of incidence from 30 deg. to 60 deg. The angular distributions of emitted matter are determined by means of SIMS depth profiles. Our series of experiments show an evolution of the preferential direction of emission as well as the spreading around this direction in function of the characteristics of the ion beam. The second objective is the study of the evolution of the stoichiometry of the deposit in function of the emission angle. A decrease of the As/Ga ratio around the preferential direction of emission and an increase of this ratio for oblique emission are observed for different conditions of primary bombardment. Considering that the angular distribution depends on the depth of origin, our results suggest that the Cs{sup +} bombardment changes the stoichiometry of the near-surface layers of the sample with an enrichment of As in the outmost layers while the sub-surface region is impoverished in As due to preferential sputtering.

  2. Light emission of sputtered particles induced by ion bombardment on water-enriched molecular ices

    Science.gov (United States)

    Lee, Chin Shuang; Ip, Wing; Liu, S. H.; Hsu, G. Y.; Lee, Shyong

    2007-03-01

    We had measured the light of sputtered particles in a visible region induced by various projectiles bombarding water-enriched molecular ices, like mixed ices of CH4 + NH3 + H2O (1:1:1). In this experiment, each constituent contained in this iced sample was found to emit a characteristic wavelength of light. We believe this characteristic is due to certain ion attached to parent molecule (constituent) that are dissociated with parent molecule in the collision process. Some of those ions, before emerging out the iced film, will become neutralized and develop into excited states due to electron capture. Then the characteristic wavelengths of light will decay from these excited sputtered particles; hence, from the light emission, one can analyze the constituents of an unknown ice. On the other hand, the intensity of the distribution of light emission during ion bombardment can be interpreted as an ion-ice interaction following the similar collision mechanism as ion-metal interaction, i.e. mainly the linear-cascade collision model.

  3. Ion Fluence and Energy Effects on the Optical Properties of SS Mirrors Bombarded by Hydrogen Ions

    Energy Technology Data Exchange (ETDEWEB)

    Bardamid, A.F. [T. Shevchenko National Univ., Kiev (Ukraine); Belyaeva, A.I. [National Technical Univ. KhPI, Kharkov (Ukraine); Bondarenko, V.N. [NSC KIPT, Kharkov (Ukraine)] (and others)

    2003-04-01

    The effects of hydrogen ion (H{sub 3}{sup +}) bombardment on the optical properties of polycrystal stainless steel (SS) mirrors were investigated. Ellipsometry, profilometry, scanning electron microscopy, angle distribution of scattered light, and spectral reflectance were used to characterize the surfaces. Results for the bombardment of SS mirrors with ions of fixed energy (0.3, 0.65 and 1.5 keV/H), with ion flux density (0.5-2) x 10{sup 20} H/m{sup 2}/s up to fluences of (1.1-4.3) x 10{sup 24} H/m{sup 2} are presented. The data show that the surface roughness rises with both increasing ion energy and ion fluence, and that surface roughening leads to an increase of the scattered light with a corresponding decrease of reflectance at normal incidence. The thickness of the apparent layer, obtained by ellipsometry, was found to rise with increasing ion energy at fixed ion fluence and with increasing ion fluence at fixed ion energy. Possible mechanisms for the ion energy effect on the degradation rate of stainless steel mirrors and the origin of the apparent layer are discussed.

  4. Experiment and analysis on back-bombardment effect in thermionic RF gun

    CERN Document Server

    Kii, T; Ikeda, R; Dong, Z W; Masuda, K; Toku, H; Yoshikawa, K; Yamazaki, T

    2001-01-01

    A serious problem for RF guns with thermionic guns is the back-bombardment effect, which makes the operation of the RF guns unstable owing to the instability of the cathode temperature. To find out how to solve the problem, we tried to evaluate the effect of back-bombardment. We have measured the temperature of cathode surface by an infrared radiation thermometer during the generation of electron beams from our S-band thermionic RF gun with 4.5 cavities. As a consequence, it was found that the temperature of cathode surface increased about 15 deg. C while the beam was on. This implies that current density on cathode surface tends to be unstable because the back-streaming electrons give energy to the cathode. We calculated the amount of the energy transfer by means of an energy-balance equation of thermal transport. Then we compared the result with the total energy of back-streaming electrons calculated by a 2-D particle simulation code KUBLAI. By comparison of two results, we could roughly estimate the energy...

  5. Crater densities within young, large craters on Rhea and Dione: Towards understanding the recent Saturnian bombardment

    Science.gov (United States)

    Rodriguez Sanchez-Vahamonde, Carolina; Rivera-Valentin, Edgard G.; Kirchoff, Michelle

    2017-10-01

    The cratering flux for the inner Solar System is partially constrained by geochronological measurements of returned lunar samples and martian meteorites combined with cratering studies. For the outer Solar System, minimal constraints on the bombardment history are derived from dynamical simulations, historical observations of cometary impacts onto the gas giants, and cratering studies. Here, in order to specifically resolve the cratering flux experienced by the Saturnian system, we use high resolution Cassini Imaging Science Subsystem (ISS) data to conduct crater counts on the floors of young, large craters on Rhea and Dione to investigate their relative crater formation age. These two mid-sized moons of Saturn have been shown to have dissimilar crater distributions, which may imply impacts by different populations. Crater diameter and locations of observed small craters between ~100s of meters to ~10s of kilometers within large craters are recorded, where the limit of the smallest crater observable is constrained by the image resolution. Relative crater ages are compared through their cumulative crater density, and populations via the standard R-plot. Ultimately, crater densities within young, large craters on these moons can be compared with crater ages inferred from crystallinity studies using Cassini VIMS data to refine our understanding of the outer Solar System bombardment.

  6. Ion Back-Bombardment of GaAs Photocathodes Inside DC High Voltage Electron Guns

    CERN Document Server

    Grames, Joseph M; Brittian, Joshua; Charles, Daniel; Clark, Jim; Hansknecht, John; Lynn Stutzman, Marcy; Poelker, Matthew; Surles-Law, Kenneth E

    2005-01-01

    The primary limitation for sustained high quantum efficiency operation of GaAs photocathodes inside DC high voltage electron guns is ion back-bombardment of the photocathode. This process results from ionization of residual gas within the cathode/anode gap by the extracted electron beam, which is subsequently accelerated backwards to the photocathode. The damage mechanism is believed to be either destruction of the negative electron affinity condition at the surface of the photocathode or damage to the crystal structure by implantation of the bombarding ions. This work characterizes ion formation within the anode/cathode gap for gas species typical of UHV vacuum chambers (i.e., hydrogen, carbon monoxide and methane). Calculations and simulations are performed to determine the ion trajectories and stopping distance within the photocathode material. The results of the simulations are compared with test results obtained using a 100 keV DC high voltage GaAs photoemission gun and beamline at currents up to 10 mA D...

  7. Ion Fluence and Energy Effects on the Optical Properties of SS Mirrors Bombarded by Hydrogen Ions

    Science.gov (United States)

    Bardamid, A. F.; Belyaeva, A. I.; Bondarenko, V. N.; Davis, J. W.; Galuza, A. A.; Garkusha, I. E.; Haasz, A. A.; Konovalov, V. G.; Kudlenko, A. D.; Poon, M.; Ryzhkov, I. V.; Solodovchenko, S. I.; Shtan, A. F.; Voitsenya, V. S.; Yakimov, K. I.

    The effects of hydrogen ion (H3+) bombardment on the optical properties of polycrystal stainless steel (SS) mirrors were investigated. Ellipsometry, profilometry, scanning electron microscopy, angle distribution of scattered light, and spectral reflectance were used to characterize the surfaces. Results for the bombardment of SS mirrors with ions of fixed energy (0.3, 0.65 and 1.5 keV/H), with ion flux density >(0.5-2) · 1020 H/m2s up to fluences of (1.1-4.3) · 1024 H}/m2 are presented.  The data show that the surface roughness rises with both increasing ion energy and ion fluence, and that surface roughening leads to an increase of the scattered light with a corresponding decrease of reflectance at normal incidence. The thickness of the apparent layer, obtained by ellipsometry, was found to rise with increasing ion energy at fixed ion fluence and with increasing ion fluence at fixed ion energy.  Possible mechanisms for the ion energy effect on the degradation rate of stainless steel mirrors and the origin of the apparent layer are discussed.

  8. Determination of lead, cadmium and mercury in blood for assessment of environmental exposure: A comparison between inductively coupled plasma-mass spectrometry and atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Christopher D. [Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States); Lewis, Miles E. [Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States); Geraghty, Ciaran M. [Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States); Barbosa, Fernando [Faculdade de Cinecias Farmaceuticas de Ribeirao Preto, Universidade de Sao Paolo, Ribeirao Preto-Sao Paolo (Brazil); Parsons, Patrick J. [Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States) and Department of Environmental Health Sciences, School of Public Health, University of Albany, State University of New York, Albany, NY 12201-0509 (United States)]. E-mail: patrick.parsons@wadsworth.org

    2006-08-15

    A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 {mu}l of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 {mu}g dl{sup -1} for Pb, 0.09 {mu}g l{sup -1} for Cd; and 0.17 {mu}g l{sup -1} for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 {mu}g dl{sup -1}, 0.54 {mu}g l{sup -1}, and 0.6 {mu}g l{sup -1}, for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (a) the New York State Department of Health's Wadsworth Center, Albany, NY, USA (b) L'Institut National de Sante Publique du Quebec, Centre de Toxicologie du Quebec, Canada (c) Friedrich-Alexander University, Erlangen, Germany, and (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

  9. Determination of lead, cadmium and mercury in blood for assessment of environmental exposure: A comparison between inductively coupled plasma mass spectrometry and atomic absorption spectrometry

    Science.gov (United States)

    Palmer, Christopher D.; Lewis, Miles E.; Geraghty, Ciaran M.; Barbosa, Fernando; Parsons, Patrick J.

    2006-08-01

    A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 μl of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 μg dl - 1 for Pb, 0.09 μg l - 1 for Cd; and 0.17 μg l - 1 for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 μg dl - 1 , 0.54 μg l - 1 , and 0.6 μg l - 1 , for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (a) the New York State Department of Health's Wadsworth Center, Albany, NY, USA (b) L'Institut National de Santé Publique du Québec, Centre de Toxicologie du Québec, Canada, (c) Friedrich-Alexander University, Erlangen, Germany, and (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

  10. Ion bombardment induced buried lateral growth: the key mechanism for the synthesis of single crystal diamond wafers

    Science.gov (United States)

    Schreck, Matthias; Gsell, Stefan; Brescia, Rosaria; Fischer, Martin

    2017-03-01

    A detailed mechanism for heteroepitaxial diamond nucleation under ion bombardment in a microwave plasma enhanced chemical vapour deposition setup on the single crystal surface of iridium is presented. The novel mechanism of Ion Bombardment Induced Buried Lateral Growth (IBI-BLG) is based on the ion bombardment induced formation and lateral spread of epitaxial diamond within a ~1 nm thick carbon layer. Starting from one single primary nucleation event the buried epitaxial island can expand laterally over distances of several microns. During this epitaxial lateral growth typically thousands of isolated secondary nuclei are generated continuously. The unique process is so far only observed on iridium surfaces. It is shown that a diamond single crystal with a diameter of ~90 mm and a weight of 155 carat can be grown from such a carbon film which initially consisted of 2 · 1013 individual grains.

  11. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-09-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10{sup 15} to 10{sup 16} ions/cm{sup 2}. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  12. Reactive magnetron sputtering of highly (001)-textured WS{sub 2-x} films: Influence of Ne{sup +}, Ar{sup +} and Xe{sup +} ion bombardment on the film growth

    Energy Technology Data Exchange (ETDEWEB)

    Ellmer, K.; Seeger, S.; Sieber, I. [Hahn-Meitner-Institut Berlin, Dept. Solare Energetik, Glienicker Str. 100, 14109 Berlin (Germany); Bohne, W.; Roehrich, J.; Strub, E. [Hahn-Meitner-Institut Berlin, Dept. Ionenstrahllabor, Glienicker Str. 100, 14109 Berlin (Germany); Mientus, R. [Opto-Transmitter-Umweltschutz-Technologie e.V., Koepenicker Str. 325b, 12555 Berlin (Germany)

    2006-02-01

    Layer-type van der Waals semiconductor WS{sub 2-x} films were grown by radio frequency reactive magnetron sputtering from a metallic tungsten target onto oxidized silicon substrates. The sputtering atmosphere consisted of 75% hydrogen sulfide and 25% neon, argon or xenon. The substrate voltage and hence the energy of the ions bombarding the growing film, was varied from about 20 V (floating potential) to -80 V. By in situ energy-dispersive X-ray diffraction the growth of the films was monitored and by elastic recoil detection analysis the film composition was measured. It was found that with xenon in the sputtering atmosphere a substrate voltage of -20 V is sufficient to suppress the crystalline film growth, while for argon as the sputtering rare gas this occurs only at -80 V. The disturbed film growth is accompanied by a sulfur loss of the growing WS{sub 2-x} films down to x = 1.1 for sputtering in Ar + H{sub 2}S at a substrate potential of -60 V. The results are tentatively explained by the different momentum transfers to sulfur atoms, which is highest for argon ions. It has also to be taken into account that the low-energy xenon bombardment is a many-body cascade process with a much higher local energy density compared to argon and neon bombardment and leading to a higher defect density and a supression of the crystalline growth. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Atomic arias

    Science.gov (United States)

    Crease, Robert P.

    2009-01-01

    The American composer John Adams uses opera to dramatize controversial current events. His 1987 work Nixon in China was about the landmark meeting in 1972 between US President Richard Nixon and Chairman Mao Zedong of China; The Death of Klinghoffer (1991) was a musical re-enactment of an incident in 1985 when Palestinian terrorists kidnapped and murdered a wheelchair-bound Jewish tourist on a cruise ship. Adams's latest opera, Doctor Atomic, is also tied to a controversial event: the first atomic-bomb test in Alamogordo, New Mexico, on 16 June 1945. The opera premièred in San Francisco in 2005, had a highly publicized debut at the Metropolitan Opera in New York in 2008, and will have another debut on 25 February - with essentially the same cast - at the English National Opera in London.

  14. Atomic rivals

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  15. International Conference on Neutrino Mass, Dark Matter and Gravitational Waves, Condensation of Atoms and Monopoles, Light-cone Quantization : Orbis Scientiae '96

    CERN Document Server

    Mintz, Stephan; Perlmutter, Arnold; Neutrino Mass, Dark Matter and Gravitational Waves, Condensation of Atoms and Monopoles, Light-cone Quantization : Orbis Scientiae '96

    1996-01-01

    The International Conference, Orbis Scientiae 1996, focused on the topics: The Neutrino Mass, Light Cone Quantization, Monopole Condensation, Dark Matter, and Gravitational Waves which we have adopted as the title of these proceedings. Was there any exciting news at the conference? Maybe, it depends on who answers the question. There was an almost unanimous agreement on the overall success of the conference as was evidenced by the fact that in the after-dinner remarks by one of us (BNK) the suggestion of organizing the conference on a biannual basis was presented but not accepted: the participants wanted the continuation of the tradition to convene annually. We shall, of course, comply. The expected observation of gravitational waves will constitute the most exciting vindication of Einstein's general relativity. This subject is attracting the attention of the experimentalists and theorists alike. We hope that by the first decade of the third millennium or earlier, gravitational waves will be detected,...

  16. The effect of the molecular mass on the sputtering by electrosprayed nanodroplets

    Energy Technology Data Exchange (ETDEWEB)

    Borrajo-Pelaez, Rafael; Gamero-Castaño, Manuel, E-mail: mgameroc@uci.edu

    2015-07-30

    Highlights: • We study the effect of the molecular mass on nanodroplet sputtering of silicon. • The impact phenomenology is a strong function of the projectile’s molecular mass. • Nanodroplet sputtering intrinsically is a molecular scale phenomenon. - Abstract: Energetic bombardment of covalently bonded materials by electrosprayed nanodroplets causes sputtering and topographic changes on the surface of the target. This work investigates the influence of the projectile's molecular mass on these phenomena by sputtering single-crystal silicon wafers with a variety of liquids (molecular masses between 45.0 and 773.3 amu), and acceleration voltages. The electrosprays are characterized via time of flight to determine the charge to mass ratio of the nanodroplets which, together with the acceleration voltage, yield the impact velocity, the stagnation pressure, and the molecular kinetic energy of the projectile. The estimated range of droplet diameters is 20–79 nm, while the impact velocity, the stagnation pressure and the molecular kinetic energy range between 2.9–10 km/s, 4.7–63 GPa, and 2.1–98 eV. We find that the damage on the surface of the targets strongly depends on the molecular mass of the projectile: liquids with low molecular mass sputter significantly less and produce nanometric indentations and low surface roughness, the latter increasing moderately with stagnation pressure; in contrast, the roughness and sputtering caused by the impacts of droplets with larger molecular mass reach significantly higher values, and exhibit non-monotonic behaviors. The maximum sputtering yields for formamide, EAN, EMI-BF{sub 4}, EMI-Im, TES, and TPP are 0.20, 0.75, 1.20, 2.80, 4.00 and 2.90 silicon atoms per molecule in the projectile. These trends indicate that despite their rather large diameters, the sputtering by electrosprayed nanodroplets is intrinsically a molecular scale phenomenon.

  17. Interaction of oxygen with an AISI 314 stainless steel surface studied by ellipsometry and auger electron spectroscopy in combination with ion bombardment

    NARCIS (Netherlands)

    Stokkers, G.J.; van Silfhout, Arend; Bootsma, G.A.; Fransen, T.; Gellings, P.J.

    1983-01-01

    The influence of pretreatment (ion bombardment) on the initial oxidation of AISI 314 stainless steel has been investigated in ultra high vacuum systems with ellipsometry and Auger electron spectroscopy. The bombardment was carried out with Ar+ ions with energies up to 2.2 keV at various doses and

  18. Atomic structure under external confinement: effect of plasma on the spin orbit splitting, relativistic mass correction and Darwin term for hydrogen-like ions

    Science.gov (United States)

    Chaudhuri, Supriya K.; Mukherjee, Prasanta K.; Fricke, Burkhard

    2017-03-01

    The effect of Debye and quantum plasma environment on the structural properties such as spin orbit splitting, relativistic mass correction and Darwin term for a few iso-electronic members of hydrogen viz. C5 +, O7 +, Ne9 +, Mg11 +, Si13 +, S15 +, Ar17 +, Ca19 + and Ti21 + has been analysed systematically for the first time for a range of coupling strengths of the plasma. The Debye plasma environment has been treated under a standard screened Coulomb potential (SCP) while the quantum plasma has been treated under an exponential cosine screened Coulomb potential (ECSCP). Estimation of the spin orbit splitting under SCP and ECSCP plasma is restricted to the lowest two dipole allowed states while for the other two properties, the ground state as well as the first two excited states have been chosen. Calculations have been extended to nuclear charges for which appreciable relativistic corrections are noted. In all cases calculations have been extended up to such screening parameters for which the respective excitation energies tend towards their stability limit determined by the ionisation potential at that screening parameter. Interesting behavior of the respective properties with respect to the plasma coupling strength has been noted.

  19. Compositional change induced by ion bombardement on binary alloys. [5 KeV Ar+

    Energy Technology Data Exchange (ETDEWEB)

    Morita, K.; Nakamura, H.; Hayashibara, M.; Itoh, N. (Nagoya Univ. (Japan). Dept. of Crystalline Materials Science)

    1982-03-01

    The compositional change, induced by 5 keV Ar/sup +/ ion bombardment, of self-supporting films of Ni-Si (10%) alloy has been studied at elevated temperatures. The results are compared with those of similar studies for Ni-Au alloy and are explained using the previously suggested two-stepped segregation mechanism: the segregation from grain boundaries to the surface and that from the grains to the grain boundaries. The theoretical calculation for the two-stepped mechanism has been made for a thin film and for a thicker material. It is pointed out that the compositional change induced by sputtering of alloys at high temperatures may cause important effects on physical properties of materials.

  20. Photon counting imaging and centroiding with an electron-bombarded CCD using single molecule localisation software

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M.; Barber, Matthew J.; Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk

    2016-06-01

    Photon event centroiding in photon counting imaging and single-molecule localisation in super-resolution fluorescence microscopy share many traits. Although photon event centroiding has traditionally been performed with simple single-iteration algorithms, we recently reported that iterative fitting algorithms originally developed for single-molecule localisation fluorescence microscopy work very well when applied to centroiding photon events imaged with an MCP-intensified CMOS camera. Here, we have applied these algorithms for centroiding of photon events from an electron-bombarded CCD (EBCCD). We find that centroiding algorithms based on iterative fitting of the photon events yield excellent results and allow fitting of overlapping photon events, a feature not reported before and an important aspect to facilitate an increased count rate and shorter acquisition times.

  1. Low temperature magnetron sputter deposition of polycrystalline silicon thin films using high flux ion bombardment

    Science.gov (United States)

    Gerbi, Jennifer E.; Abelson, John R.

    2007-03-01

    We demonstrate that the microstructure of polycrystalline silicon thin films depends strongly on the flux of low energy ions that bombard the growth surface during magnetron sputter deposition. The deposition system is equipped with external electromagnetic coils which, through the unbalanced magnetron effect, provide direct control of the ion flux independent of the ion energy. We report the influence of low energy (thin films onto amorphous substrates. We use spectroscopic ellipsometry, Raman scattering, x-ray diffraction, and cross sectional transmission electron microscopy to analyze the film microstructure. We demonstrate that increasing the flux ratio of Ar+ ions to silicon neutrals (J+/J0) during growth by an order of magnitude (from 3 to 30) enables the direct nucleation of polycrystalline Si on glass and SiO2 coated Si at temperatures below 400°C. We discuss possible mechanisms for this enhancement of crystalline microstructure, including the roles of enhanced adatom mobility and the formation of shallow, mobile defects.

  2. Solar Wind Sputtering Rates of Small Bodies and Ion Mass Spectrometry Detection of Secondary Ions

    Science.gov (United States)

    Schaible, M. J.; Dukes, C. A.; Hutcherson, A. C.; Lee, P.; Collier, M. R.; Johnson, R. E.

    2017-10-01

    Solar wind interactions with the surfaces of asteroids and small moons eject atoms and molecules from the uppermost several nanometers of regolith grains through a process called sputtering. A small fraction of the sputtered species, called secondary ions, leave the surface in an ionized state, and these are diagnostic of the surface composition. Detection of secondary ions using ion mass spectrometry (IMS) provides a powerful method of analysis due to low backgrounds and high instrument sensitivities. However, the sputtered secondary ion yield and the atomic composition of the surface are not 1-to-1 correlated. Thus, relative yield fractions based on experimental measurements are needed to convert measured spectra to surface composition. Here available experimental results are combined with computationally derived solar wind sputtering yields to estimate secondary ion fluxes from asteroid-sized bodies in the solar system. The Monte Carlo simulation code SDTrimSP is used to estimate the total sputtering yield due to solar wind ion bombardment for a diverse suite of meteorite and lunar soil compositions. Experimentally measured relative secondary ion yields are analyzed to determine the abundance of refractory species (Mg+, Al+, Ca+, and Fe+) relative to Si+, and it is shown that relative abundances indicate whether a body is primitive or has undergone significant geologic reprocessing. Finally, estimates of the sputtered secondary ion fluxes are used to determine the IMS sensitivity required to adequately resolve major element ratios for nominal orbital geometries.

  3. Ion-bombardment modification of the surface of mirrors fabricated of ZrTiCuNiBe amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Voitsenya, V S; Konovalov, V G; Kovtun, K V; Naidenkova, D I; Ryzhkov, V I; Shtan' , A F; Solodovchenko, S I; Trembach, O V; Vasil' ev, A A [National Science Center ' KIPT' , 61108 Kharkov (Ukraine); Bardamid, A F [Taras Shevchenko National University, 01033 Kyiv (Ukraine); Belyaeva, A I; Slatin, K A, E-mail: voitseny@ipp.kharkov.u [National Technical University ' KPI' , 61002 Kharkov (Ukraine)

    2010-01-01

    When preparing mirror samples of amorphous metal alloys some inhomogeneities of the structure became to be seen on the surface. These inhomogeneities were modified during bombardment with ions of deuterium and argon plasma. Besides, a new blister-like type of inhomogeneities was found on the mirror surface in one experiment. In the paper a short description of obtained results are presented.

  4. Enhancement of Reflectivity of Multilayer Mirrors for Soft-X-Ray Projection Lithography by Temperature Optimization and Ion-Bombardment

    NARCIS (Netherlands)

    E. Louis,; Voorma, H. J.; Koster, N. B.; Shmaenok, L.; F. Bijkerk,; Schlatmann, R.; Verhoeven, J.; Platonov, Y. Y.; van Dorssen, G. E.; Padmore, H. A.

    1994-01-01

    In this paper we discuss two techniques to optimize the quality of multilayer x-ray mirrors, namely optimization of the temperature of the substrates during deposition and ion-bombardment of the layers. We produced Mo/Si multilayers applying both methods and present the effect on the near normal

  5. Fast neutron distributions from Be and C thick targets bombarded with 80 and 160 MeV deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Pauwels, N.; Laurent, H.; Clapier, F. [Institut de Physique Nucleaire, (IN2P3/CNRS) 91 - Orsay (France); Brandenburg, S.; Beijers, J.P.M.; Zegers, R.G.T. [Kernfysisch Versneller Institute, Groningen (Netherlands); Lebreton, L. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium); Mirea, M. [Institute of Nuclear Physics and Engineering, Bucarest (Romania); Saint-Laurent, M.G. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)

    2000-07-01

    Measured angular and energy distributions of neutrons obtained by bombarding Be and C thick targets with deuterons at 80 and 160 MeV incident energies are reported. The data were obtained using the time-of-flight method. The experimental values are compared with a modelization based on stripping formalization extended for thick targets. (authors)

  6. Constraints on planetesimal disk mass from the cratering record and equatorial ridge on Iapetus

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-Valentin, E. G.; Barr, A. C.; Lopez Garcia, E. J. [Department of Earth, Environmental, and Planetary Sciences, Brown University, 324 Brook Street, Box 1846, Providence, RI 02912 (United States); Kirchoff, M. R. [Southwest Research Institute, 1050 Walnut Street, Suite 200, Boulder, CO 80302 (United States); Schenk, P. M., E-mail: ervalentin@usra.edu [Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058 (United States)

    2014-09-10

    Iapetus, the outermost regular satellite of Saturn, has a drastic albedo dichotomy and an equatorial circumferential ridge that reaches heights of 20 km and widths of 70 km. This moon is thought to have formed concurrently with Saturn, and so would have experienced an intense bombardment after its formation. The ridge, which has been inferred to be one of the most ancient features on Iapetus' surface, could reasonably be expected to have been eroded by impacts; however, it has retained long continuous sections and a nearly pristine triangular shape with ridge slopes reaching ∼40°. We use these observations, along with crater counts on Iapetus' surface, to constrain the total bombardment mass experienced by the satellite since its formation. The ridge morphology and the global crater population recorded on Iapetus both suggest similar bombardment masses, indicating the ridge is indeed ancient. We find that the inferred total bombardment mass incident on Iapetus is less than 20% of the bombardment predicted by the classic Nice model for early solar system evolution. Our results, though, support the recently proposed scenarios of planetesimal-driven migration of the young outer planets including more realistic disk conditions.

  7. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  8. Mass attenuation coefficient (μ/ρ), effective atomic number (Z{sub eff}) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil); Goncalves Z, E., E-mail: madelon@cdtn.br [Pontifice Catholic University of Minas Gerais, Av. Dom Jose Gaspar 500, Belo Horizonte 30535-901, Minas Gerais (Brazil)

    2015-10-15

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z{sub eff} of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z{sub eff} using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  9. HERSCHEL KEY PROGRAM, ''DUST, ICE, AND GAS IN TIME'' (DIGIT): THE ORIGIN OF MOLECULAR AND ATOMIC EMISSION IN LOW-MASS PROTOSTARS IN TAURUS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong-Eun; Lee, Seokho [Department of Astronomy and Space Science, Kyung Hee University, Yongin-shi, Kyungki-do 449-701 (Korea, Republic of); Lee, Jinhee [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602-2451 (United States); Evans II, Neal J.; Green, Joel D., E-mail: jeongeun.lee@khu.ac.kr [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)

    2014-10-01

    Six low-mass embedded sources (L1489, L1551-IRS5, TMR1, TMC1-A, L1527, and TMC1) in Taurus have been observed with Herschel-PACS to cover the full spectrum from 50 to 210 μm as part of the Herschel key program, ''Dust, Ice, and Gas In Time''. The relatively low intensity of the interstellar radiation field surrounding Taurus minimizes contamination of the [C II] emission associated with the sources by diffuse emission from the cloud surface, allowing study of the [C II] emission from the source. In several sources, the [C II] emission is distributed along the outflow, as is the [O I] emission. The atomic line luminosities correlate well with each other, as do the molecular lines, but the atomic and molecular lines correlate poorly. The relative contribution of CO to the total gas cooling is constant at ∼30%, while the cooling fraction by H{sub 2}O varies from source to source, suggesting different shock properties resulting in different photodissociation levels of H{sub 2}O. The gas with a power-law temperature distribution with a moderately high density can reproduce the observed CO fluxes, indicative of CO close to LTE. However, H{sub 2}O is mostly subthermally excited. L1551-IRS5 is the most luminous source (Ł{sub bol} = 24.5 L {sub ☉}) and the [O I] 63.1 μm line accounts for more than 70% of its FIR line luminosity, suggesting complete photodissociation of H{sub 2}O by a J shock. In L1551-IRS5, the central velocity shifts of the [O I] line, which exceed the wavelength calibration uncertainty (∼70 km s{sup –1}) of PACS, are consistent with the known redshifted and blueshifted outflow direction.

  10. Chameleon Induced Atomic Afterglow

    CERN Document Server

    Brax, Philippe

    2010-01-01

    The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between atomic energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant magnetic field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the magnetic field have been turned off, and could be used to probe the interactions of the chameleon field with matter.

  11. Atomic Power

    African Journals Online (AJOL)

    controls the electrons around it, and like a strong spring pushes other nuclei away. Later experiments ... 6Cl 2, because its mass number (A) = 12 and its nucleus contains 6 protons and 6 neutrons. However, ... gamma-radiation. Enrico Fermi, the Italian physicist made impor- tant contributions here. It occurred to him to use.

  12. Laser sputter neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

  13. Atom Interferometry for detection of Gravity Waves-a Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atom interferometers are more sensitive to inertial effects. This is because atoms in their inertial frame are ideal test masses for detection of gravity effects...

  14. Extended metastable Al solubility in cubic VAlN by metal-ion bombardment during pulsed magnetron sputtering: film stress vs subplantation

    Science.gov (United States)

    Greczynski, G.; Mráz, S.; Ruess, H.; Hans, M.; Lu, J.; Hultman, L.; Schneider, J. M.

    2017-07-01

    Dynamic ion-recoil mixing of near-film-surface atomic layers is commonly used to increase the metastable solubility limit xmax in otherwise immiscible thin film systems during physical vapor deposition. Recently, Al subplantation achieved by irradiating the film growth surface with Al+ metal-ion flux was shown to result in an unprecedented xmax for VAlN, far above values obtained with gas ion irradiation. However, it is reasonable to assume that ion irradiation necessary for subplantation also leads to a compressive stress σ buildup. In order to separate the effects of Al+ bombardment on σ and xmax, and realize low-stress high-xmax nitride alloys, we grow metastable cubic V1-xAlxN (0.17 ≤ x ≤ 0.74) films using reactive magnetron sputtering under different ion irradiation conditions. Al and V targets are operated in Ar/N2 discharges employing (i) conventional DC (Ar+, N2+), (ii) hybrid High-power pulsed magnetron sputtering (HIPIMS)/DC processing with one type of metal ion present (Al+ or V+/V2+), and (iii) HIPIMS with concurrent Al+ and V+/V2+ fluxes. Comparison to the ab initio calculated Al solubility limit reveals that xmax = 0.55 achieved with V+/V2+ irradiation is entirely accountable for by stress. In contrast, Al+ fluxes provide a substantial increase in xmax to 0.63, which is 12% higher than that expected based on the stress-induced increase in metastable solubility. Correlative stress and atom probe tomography data confirm that the metastable Al solubility enhancement is enabled by Al+ subplantation. The here proposed processing strategy allows for growth of single-phase cubic nitride alloys with significantly increased Al concentrations embodying tremendous promise for substantial improvements in high temperature oxidation resistance and mitigates the risk of stress-induced adhesive or cohesive coating failure.

  15. Plasma Desorption Mass Spectrometry analysis of HCOOH ice

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, D.P.P.; Rocco, M.L.M. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21949-900 Rio de Janeiro, RJ (Brazil); Boechat-Roberty, H.M. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Centro, Rio de Janeiro, RJ (Brazil); Iza, P.; Martinez, R. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil); Homem, M.G.P. [Laboratorio Nacional de Luz Sincrotron (LNLS), Box 6192, 13084-971 Campinas, SP (Brazil); Silveira, E.F. da [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil)], E-mail: enio@vdg.fis.puc-rio.br

    2007-03-15

    Planetary magnetospheres, in which outer planet satellites orbit, are bombarded by energetic particles inducing chemical and physical changes in their icy surfaces. The existing condensed gases react to form new products, which then undergo thermal evolution from the natural day/night cycles of these satellites. Plasma irradiation of ice causes phase changes, e.g., water ice from crystalline to amorphous over short timescales. When ice is recrystallized by heating, the surface layers retain some disorder, which promote reactions among adsorbed molecules such as H{sub 2}O, CO{sub 2}, CH{sub 2}CO, HCOOH and theirs radiolysis products. In this work, chemical reactions involving formic acid condensed at 56 K are analyzed by using Plasma Desorption Mass Spectrometry-time-of-flight ({sup 252}Cf-PDMS-TOF). Mass spectra of positive and negative desorbed ions were obtained, giving information on the structure and abundance of the molecules on the ice; the expected cations and anions generated by the HCOOH dissociation have been observed. Furthermore, several series of cluster ions were also detected, all exhibiting the structure X{sub n}Y{sub m}R{sup {+-}}, where X and Y are the neutral ice molecules, such as HCOOH or H{sub 2}O, and R{sup {+-}} is either an atomic or a molecular ion, such as H{sup +}, H{sub 3}O{sup +} or COOH{sup -}. In general, the desorption yields of the observed positive and negative ions are characterized by a decreasing exponential function as the emitted ion mass increases; however, the (HCOOH){sub n}OH{sup -} series presents its maximum at n = 8.

  16. High Atom Number in Microsized Atom Traps

    Science.gov (United States)

    2015-12-14

    Final Performance Report on ONR Grant N00014-12-1-0608 High atom number in microsized atom traps for the period 15 May 2012 through 14 September...TYPE Final Technical Report 3. DATES COVERED (From - To) 05/15/2012-09/14/2012 4. TITLE AND SUBTITLE High atom number in microsized atom traps...forces for implementing a small-footprint, large-number atom -chip instrument. Bichromatic forces rely on absorption and stimulated emission to produce

  17. Clarifying atomic weights: A 2016 four-figure table of standard and conventional atomic weights

    Science.gov (United States)

    Coplen, Tyler B.; Meyers, Fabienne; Holden, Norman E.

    2017-01-01

    To indicate that atomic weights of many elements are not constants of nature, in 2009 and 2011 the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) replaced single-value standard atomic weight values with atomic weight intervals for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine, and thallium); for example, the standard atomic weight of nitrogen became the interval [14.00643, 14.00728]. CIAAW recognized that some users of atomic weight data only need representative values for these 12 elements, such as for trade and commerce. For this purpose, CIAAW provided conventional atomic weight values, such as 14.007 for nitrogen, and these values can serve in education when a single representative value is needed, such as for molecular weight calculations. Because atomic weight values abridged to four figures are preferred by many educational users and are no longer provided by CIAAW as of 2015, we provide a table containing both standard atomic weight values and conventional atomic weight values abridged to four figures for the chemical elements. A retrospective review of changes in four-digit atomic weights since 1961 indicates that changes in these values are due to more accurate measurements over time or to the recognition of the impact of natural isotopic fractionation in normal terrestrial materials upon atomic weight values of many elements. Use of the unit “u” (unified atomic mass unit on the carbon mass scale) with atomic weight is incorrect because the quantity atomic weight is dimensionless, and the unit “amu” (atomic mass unit on the oxygen scale) is an obsolete term: Both should be avoided.

  18. Energy spectra of sputtered positive ions under Cs{sup +} bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Gnaser, Hubert, E-mail: gnaser@rhrk.uni-kl.d [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, D-67663 Kaiserslautern (Germany); Institute for Surface and Thin-Film Analysis IFOS, Trippstadter Str. 120, D-67663 Kaiserslautern (Germany)

    2011-05-01

    The emission-energy spectra of atomic and molecular secondary ions sputtered from various metals and semiconductors (Al, Cu, In, Si, InP, and InSb) under 5.5-keV Cs{sup +} irradiation were investigated. The emitted ions were detected in a high-sensitivity double-focusing secondary-ion mass spectrometer. Specifically, the energy distributions of Cs{sup +}, Cs{sub 2}{sup +}, MCs{sup +}, and M{sup +} ions (where M designates one of the target elements) were recorded for emission energies E {<=} 125 eV. All ion species exhibit a peak at low energy (E < 5 eV), but differ significantly in the respective fall-off to high emission energies. The influence of the oxygen partial pressure in the vicinity of the sputtered surface on the energy spectra was examined for Cs{sup +} ions emitted from Si. With an increase of the ratio r of the O{sub 2} flux to the Cs{sup +} flux, the spectra shift to higher emission-energy values, with the total shift amounting to {approx}0.45 eV at a value of r {approx} 3.3. Concurrently, the intensity of Cs{sup +} increases by {approx}30%. The measured emission distributions of Cs{sup +} ions from different samples were compared with the predictions of the electron-tunneling model of secondary-ion formation. It is found that the experimental spectra can be reproduced quite well when employing specific sets of parameters in that theoretical concept. The possible limitations of such a comparison are discussed.

  19. Bacterial spore survival after exposure to HZE particle bombardment -implication for the lithopanspermia hypothesis.

    Science.gov (United States)

    Moeller, Ralf; Berger, Thomas; Matthiä, Daniel; Okayasu, Ryuichi; Kitamura, H.; Reitz, Guenther

    Based on their unique resistance to various space parameters, bacterial spores (mainly spores of Bacillus subtilis) are one of the model systems used for astrobiological studies. More re-cently, spores of B. subtilis have been applied for experimental research on the likelihood of interplanetary transfer of life. Since its first postulation by Arrhenius in 1903, the pansper-mia hypothesis has been revisited many-times, e.g. after the discovery of several lunar and Martian meteorites on Earth [1,2]. These information provided intriguing evidence that rocks may naturally be transferred between the terrestrial planets. The scenario of panspermia, now termed "lithopanspermia" involves three basic hypothetical steps: (i) the escape process, i.e. removal to space of biological material, which has survived being lifted from the surface to high altitudes; (ii) interim state in space, i.e., survival of the biological material over time scales comparable with interplanetary or interstellar passage; (iii) the entry process, i.e. nondestruc-tive deposition of the biological material on another planet [2]. In our research, spores of B. subtilis were used to study the effects of galactic cosmic radiation on spore survival and induced mutations. On an interplanetary journey, outside a protective magnetic field, spore-containing rocks would be exposed to bombardment by high-energy charged particle radiation from galac-tic sources and from the sun. Air-dried spore layers on three different host materials (i.e., non-porous igneous rocks (gabbro), quartz, and spacecraft analog material (aluminum)) were irradiated with accelerated heavy ions (Helium and Iron) with a LET (linear energy transfer) ˆ of 2 and 200 keV/Am, at the Heavy Ion Medical Accelerator (HIMAC) at the National In-stitute of Radiological Sciences, (NIRS), Chiba, Japan in the frame of the HIMAC research project 20B463 "Characterization of heavy ion-induced damage in Bacillus subtilis spores and their global

  20. Determination of butyl- and phenyltin compounds in human urine by HS-SPME after derivatization with tetraethylborate and subsequent determination by capillary GC with microwave-induced plasma atomic emission and mass spectrometric detection.

    Science.gov (United States)

    Zachariadis, G A; Rosenberg, E

    2009-04-30

    A headspace solid-phase micro-extraction (HS-SPME) method was developed and optimized for gas chromatographic separation and determination of commonly found organotin compounds in human urine after potential exposure. Butyl- and phenyltin compounds were in situ derivatized to ethylated derivatives by sodium tetraethylborate (NaBEt(4)) directly in the urine matrix. The relevant parameters affecting the yield of the SPME procedure were examined using tetrabutyltin as internal standard. The method was optimized for direct use in the analysis of undiluted human urine samples and mono-, di- and tri-substituted butyl- and phenyltin compounds could be determined after a 15-min headspace extraction time at room temperature. The selectivity of the microwave-induced plasma atomic emission detector (MIP-AED) as an element specific detector in combination with the relatively selective sample preparation technique of HS-SPME allowed the interference-free detection of the organotin compounds in all cases. A quadrupole mass spectrometer was used in parallel experiments as a detector for the confirmation of the identity molecular structure of the eluted compounds. The performance characteristics of the developed method are given for the determination of mixtures of these compounds. Finally the proposed method was applied to the analysis of several human urine samples.

  1. Determination of hafnium at the 10(-4)% level (relative to zirconium content) using neutron activation analysis, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry.

    Science.gov (United States)

    Smolik, Marek; Polkowska-Motrenko, Halina; Hubicki, Zbigniew; Jakóbik-Kolon, Agata; Danko, Bożena

    2014-01-02

    Hafnium at the very low level of 1-8 ppm (in relation to zirconium) was determined in zirconium sulfate solutions (originating from investigations of the separation of ca. 44 ppm Hf from zirconium by means of the ion exchange method) by using three independent methods: inductively coupled plasma mass spectrometry (ICP MS), neutron activation analysis (NAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of NAA and ICP MS determinations were consistent with each other across the entire investigated range (the RSD of both methods did not exceed 38%). The results of ICP-AES determination were more diverse, particularly at less than 5 ppm Hf (RSD was significantly higher: 29-253%). The ion exchange method exploiting Diphonix(®) resin proved sufficient efficiency in Zr-Hf separation when the initial concentration ratio of the elements ([Zr]0/[Hf]0) ranged from 1200 to ca. 143,000. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Salmon Muscle Adherence to Polymer Coatings and Determination of Antibiotic Residues by Reversed-Phase High-Performance Liquid Chromatography Coupled to Selected Reaction Monitoring Mass Spectrometry, Atomic Force Microscopy, and Fourier Transform Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    E. Zumelzu

    2015-01-01

    Full Text Available The persistent adhesion of salmon muscle to food container walls after treatment with urea solution was observed. This work evaluated the diffusion of antibiotics from the salmon muscle to the polyethylene terephthalate (PET coating protecting the electrolytic chromium coated steel (ECCS plates. New aquaculture production systems employ antibiotics such as florfenicol, florfenicol amine, oxytetracycline, and erythromycin to control diseases. The introduction of antibiotics is a matter of concern regarding the effects on human health and biodiversity. It is important to determine their impact on the adhesion of postmortem salmon muscle to can walls and the surface and structural changes affecting the functionality of multilayers. This work characterized the changes occurring in the multilayer PET polymer and steel of containers by electron microscopy, 3D atomic force microscopy (3D-AFM, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectroscopy (FT-IR analyses. A robust mass spectrometry methodology was employed to determine the presence of antibiotic residues. No evidence of antibiotics was observed on the protective coating in the range between 0.001 and 2.0 ng/mL; however, the presence of proteins, cholesterol, and alpha-carotene was detected. This in-depth profiling of the matrix-level elements is relevant for the use of adequate materials in the canning export industry.

  3. Gravitational Wave Detection with Single-Laser Atom Interferometers

    Science.gov (United States)

    Yu, Nan; Tinto, Massimo

    2011-01-01

    A new design for a broadband detector of gravitational radiation relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser are used for operating the two atom interferometers. The innovation here involves the fact that the atoms in the atom interferometers are not only considered as perfect test masses, but also as highly stable clocks. Atomic coherence is intrinsically stable, and can be many orders of magnitude more stable than a laser.

  4. Preparation and tandem mass spectrometric analyses of deuterium-labeled cysteine-containing leukotrienes.

    Science.gov (United States)

    Raftery, M J; Thorne, G C; Orkiszewski, R S; Gaskell, S J

    1990-08-01

    Leukotrienes (LT) C4, E4 and N-acetyl-E4, their respective monomethyl esters and 14,15-2H2 analogs have been synthesized. The collisionally activated decompositions of the [M + H]+ and [M - H]- ions formed by fast atom bombardment (FAB) have been studied by tandem mass spectrometry using a hybrid sector/quadrupole instrument. Structurally informative product ion spectra were obtained for each analyte; the fragmentation pathways proposed are consistent with the parallel data obtained for labeled and derivatized species. Fragmentation of [M + H]+ ions occurs prominently via cleavage of the thioether linkage with charge retention on the cysteine-containing (predominant for LTC4) or lipid-derived (predominant for LTE4) moieties. More pronounced differences were observed between the fragmentations of [M - H]- ions derived from LTC4 and LTE4; the preference for charge retention, however, parallels that observed for the fragmentation of [M + H]+ ions. Selected ion monitoring during continuous-flow FAB mass spectrometric analysis of authentic LTC4 indicated a low-picogram detection limit.

  5. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  6. Genetic Transformation of Metroxylon sagu (Rottb. Cultures via Agrobacterium-Mediated and Particle Bombardment

    Directory of Open Access Journals (Sweden)

    Evra Raunie Ibrahim

    2014-01-01

    Full Text Available Sago palm (Metroxylon sagu is a perennial plant native to Southeast Asia and exploited mainly for the starch content in its trunk. Genetic improvement of sago palm is extremely slow when compared to other annual starch crops. Urgent attention is needed to improve the sago palm planting material and can be achieved through nonconventional methods. We have previously developed a tissue culture method for sago palm, which is used to provide the planting materials and to develop a genetic transformation procedure. Here, we report the genetic transformation of sago embryonic callus derived from suspension culture using Agrobacterium tumefaciens and gene gun systems. The transformed embryoids cells were selected against Basta (concentration 10 to 30 mg/L. Evidence of foreign genes integration and function of the bar and gus genes were verified via gene specific PCR amplification, gus staining, and dot blot analysis. This study showed that the embryogenic callus was the most suitable material for transformation as compared to the fine callus, embryoid stage, and initiated shoots. The gene gun transformation showed higher transformation efficiency than the ones transformed using Agrobacterium when targets were bombarded once or twice using 280 psi of helium pressure at 6 to 8 cm distance.

  7. Modeling of evolution of shape of ductile metal disk for isotropic bombardment

    Science.gov (United States)

    Osipov, Dulustaan R.; Yakovlev, Boris V.; Matveev, Andrei I.; Osipov, Dulustan A.

    2017-11-01

    This work is devoted to a calculation of formation time of a toroidal shape of a flat piece of ductile metal in enrichment of minerals. Gold grains occurring in nature, in most cases, originally have a form of a flat plate (the scaly form). Continuous bombardment of the surface of a piece of gold with surrounding grains of sand during the enrichment of ores in various jigging, separation, and crusher devices results in the piece assuming a toroidal shape. When separating, the shape of the grains in the form of a torus is considered to be the most effective. Therefore, the problem of calculation of the formation time of the toroidal shape of the piece of gold is urgent. In this paper, we propose a physical model for the formation of the toroidal shape of the piece of ductile metal, in which an isotropic, homogeneous flow of particles deforming a plane body (disk) is introduced. Based on the proposed physical model, a mathematical model of evolution of the surface under deformation of a body was developed. A first-order differential equation is obtained with respect to the deformable surface, which is solved by the Runge-Kutta method. As a result of the study, the dependence of the deformed surface on the time was determined.

  8. Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment

    Directory of Open Access Journals (Sweden)

    D. Tahir

    2014-08-01

    Full Text Available The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF by using QUEELS-ε(k-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.

  9. Genetic Transformation of Metroxylon sagu (Rottb.) Cultures via Agrobacterium-Mediated and Particle Bombardment

    Science.gov (United States)

    Ibrahim, Evra Raunie

    2014-01-01

    Sago palm (Metroxylon sagu) is a perennial plant native to Southeast Asia and exploited mainly for the starch content in its trunk. Genetic improvement of sago palm is extremely slow when compared to other annual starch crops. Urgent attention is needed to improve the sago palm planting material and can be achieved through nonconventional methods. We have previously developed a tissue culture method for sago palm, which is used to provide the planting materials and to develop a genetic transformation procedure. Here, we report the genetic transformation of sago embryonic callus derived from suspension culture using Agrobacterium tumefaciens and gene gun systems. The transformed embryoids cells were selected against Basta (concentration 10 to 30 mg/L). Evidence of foreign genes integration and function of the bar and gus genes were verified via gene specific PCR amplification, gus staining, and dot blot analysis. This study showed that the embryogenic callus was the most suitable material for transformation as compared to the fine callus, embryoid stage, and initiated shoots. The gene gun transformation showed higher transformation efficiency than the ones transformed using Agrobacterium when targets were bombarded once or twice using 280 psi of helium pressure at 6 to 8 cm distance. PMID:25295258

  10. Influence of particle bombardment on microstructure and internal stresses of refractory metal suicides on silicon

    Science.gov (United States)

    Hardtke, Ch.; Schilling, W.; Ullmaier, H.

    1991-07-01

    First results on microstructural changes and stress relaxation in thin refractory metal suicide films (TaSi 2 and MoSi 2) caused by particle bombardment are reported. The polycrystalline films had initial tensile stresses of some 10 9 Pa. Exposed to irradiation with Ge ions of 400 keV, both suicides showed a similar stress relaxation behaviour as a function of dose. During room-temperature implantation the initial tensile stress rapidly decreased and turned into compressive stress. Continuous irradiation partly relaxed the compressive stress and resulted in a saturation value of some -10 8 Pa. With increasing implantation temperature, the buildup of compressive stress gradually vanished, leaving only the initial decrease of tensile stress which finally approached zero. Based on microstructural investigations (TEM and X-ray diffraction) it is proposed to explain this behaviour by the combined action of two processes: relaxation of tensile stress by a volume increase due to irradiation-induced amorphization, and Frenkel defect production and relaxation of compressive stress by irradiation-induced densification of amorphous regions and/or Frenkel defect elimination.

  11. Improvement of the magnetron sputtered coating adhesion through pulsed bombardment by high-energy ions

    Science.gov (United States)

    Melnik, Yu A.; Metel, A. S.

    2017-05-01

    Comparative study of titanium nitride deposition has been carried out, the growing coating being uninterruptedly bombarded by 100-eV ions or ions accelerated by high-voltage pulses applied to the substrate. The study revealed that microhardness of coatings synthesized using 25-kV pulses rises from 21 GPa to 29 GPa when percentage of nitrogen in the mixture with argon increases from 15% to 20%. With a further increase of nitrogen percentage to 30%, the microhardness slightly diminishes to 27 GPa. In contrast to golden coatings synthesized at low-voltage substrate biasing, the color of titanium nitride coating produced using high-voltage pulses is brown. The most striking difference of coating deposited using high-voltage pulses applied to the substrate is its perfect adhesion despite the interface formation at the room temperature without any preheating and activation. The adhesion characterization using a scratch-tester has revealed that critical loads of coatings synthesized using 25-kV pulses are several times higher than those of conventional nitride coatings synthesized at uninterrupted substrate biasing of 100 V. When the pulse amplitude diminishes to 5 kV, the critical loads and microhardness of the coating decrease to conventional values.

  12. ULTRAVIOLET AND INFRARED SPECTRA OF ELECTRON-BOMBARDED SOLID NITROGEN AND METHANE DILUTED IN SOLID NITROGEN

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yu-Jong; Chuang, Shiang-Jiun; Huang, Tzu-Ping [National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Chen, Hui-Fen, E-mail: yjwu@nsrrc.org.tw [Department of Medical and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1 st Road, Kaohsiung 80708, Taiwan (China)

    2013-05-01

    The infrared (IR) and ultraviolet (UV) absorption spectra of pure solid N{sub 2} and CH{sub 4} diluted in solid N{sub 2} (1/100) irradiated with energetic electrons at 10 K were obtained. The IR absorption measurements of the electron-bombarded pure N{sub 2} solid reveal the formation of N{sub 3} and N{sub 3} {sup +}, which was confirmed by the observed electronic transitions A {sup 2}{Sigma}{sub u} {sup +}<- X {sup 2}{Pi}{sub g} of N{sub 3} and A {sup 3}{Pi}{sub u} <- X {sup 3}{Sigma}{sub g} {sup -} of N{sub 3} {sup +}. In the case of N{sub 2} ice containing a small proportion of CH{sub 4}, we have identified the products of irradiated CH{sub 4}/N{sub 2} ice, including N{sub 3}, C{sub n} N (n = 1-3), CN{sub 2}, (CN){sub 2}, CH{sub 3}N, HCN{sub 2}, HC{sub 2}N, C(NH){sub 2}, HNC, HCN, CH{sub 3}, C{sub 2}H, C{sub 2}H{sub 2}, CN{sup -}, NH{sub 3} {sup +}, and HC{sub 3}N{sup +}. UV absorption measurement of the ice sample was carried out and the possible carriers associated with the observed absorption bands were assigned and discussed.

  13. Characteristics of radiation damage in silicon bombarded with U/sup 235/ fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Takibaev, Z.S.; Gorelkinskii, Y.V.; Grishchenko, V.F.; Gerasimenko, N.N.

    1975-10-01

    The ESR method was used in a study of the properties of radiation defects in silicon bombarded with /sup 235/U fission fragments. The source of these fragments was uranium dioxide irradiated, together with silicon, by reactor neutrons. It was established that the main defects generated by fission fragments were tetravacancies (called Si--P3 centers) and centers associated with amorphization (VV centers). An analysis of the distribution function of the concentration of paramagnetic centers demonstrated that individual fission fragments were capable of creating point defects in densities sufficient for the formation of an isolated amorphous region in Si. A continuous amorphous layer near the surface of an Si crystal was observed when the fission fragment density was approx.10/sup 15/ cm/sup -2/. An estimate was obtained of the rate of introduction of paramagnetic centers whose average value was approx.10/sup 4/ cm/sup -1/ per fragment. The ESR signal disappeared completely after annealing at approx.600/sup 0/C. (AIP)

  14. Biological Effects of Low Energy Ar+ Ion Bombardment on Silkworm Eggs: a Novel Animal Model

    Science.gov (United States)

    Xu, Jiaping; Wu, Yuejin; Liu, Xuelan; Yuan, Hang; Yu, Zengliang

    2009-06-01

    In this study, we found for the first time that silkworm eggs were able to survive in vacuum for a long period of time. Subsequently, low energy Ar+ ions with different energies and fluences were used to bombard silkworm eggs so as to explore the resulting biological effects. Results showed that (i) the exposure of silkworm eggs to vacuum within 10 min did not cause significant impact on the hatching rates, while the irradiation of silkworm eggs by Ar+ ions of 25 keV or 30 keV with fluences ranging from 2.6×2.6 × 1015 ion/cm2 to 8×2.6 × 1015 ion/cm2 caused a significant impact on the hatching rates, and the hatching rates decreased with the increase in the fluence and energy level; (ii) the irradiation of silkworm eggs by Ar+ ions of 30 keV with a fluence of 8×2.6 × 1015 ion/cm2 or 9×2.6 × 1015 ion/cm2 resulted in a noticeable etching on the egg shell surface which could be observed by a scanning electron microscope; and (iii) the irradiation of silkworm eggs by Ar+ ions of 30 keV with a fluence of 9×2.6 × 1015 ion/cm2 generated several mutant phenotypes which were observed in the 5th instar silkworms and a moth.

  15. Low-energy ion bombardment to tailor the interfacial and mechanical properties of polycrystalline 3C-silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fang; Li, Carolina H.; Pisano, Albert P.; Carraro, Carlo; Maboudian, Roya [Department of Chemical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 and Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027 (China); Department of Chemical Engineering, University of California, Berkeley, Berkeley, California 94720 (United States); Department of Mechanical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 (United States); Department of Chemical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 (United States)

    2010-09-15

    Low-energy Ar{sup +} ion bombardment of polycrystalline 3C-silicon carbide (poly-SiC) films is found to be a promising surface modification method to tailor the mechanical and interfacial properties of poly-SiC. The film average stress decreases as the ion energy and the bombardment time increase. Furthermore, this treatment is found to change the strain gradient of the films from positive to negative values. The observed changes in stress and strain gradient are explained by ion peening and thermal spikes models. In addition, the poly-SiC films show a significant enhancement in corrosion resistance by this treatment, which is attributed to a reduction in surface energy and to an increase in the compressive stress in the near-surface region.

  16. Photon counting imaging with an electron-bombarded CCD: Towards wide-field time-correlated single photon counting (TCSPC)

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M.; Jiggins, Stephen; Sergent, Nicolas; Zanda, Gianmarco; Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk

    2015-07-01

    Single photon detecting capabilities of an electron-bombarded CCD (EBCCD), where a photon is converted into a photoelectron that is accelerated through a high voltage before hitting the CCD chip, were characterised. The photon event pulse height distribution was found to be linearly dependent on the gain voltage. Based on these results, we propose that a gain voltage sweep during exposure in an EBCCD or EBCMOS camera would allow photon arrival time determination from the photon event pulse height with sub-frame exposure time resolution. This effectively uses an electron-bombarded sensor as a parallel-processing photoelectronic time-to-amplitude converter (TAC), or a 2-dimensional streak camera. Several applications that require timing of photon arrival, including fluorescence lifetime imaging microscopy (FLIM), may benefit from this approach. Moreover, the EBCCD was used on a fluorescence microscope to image fluorescently labelled cells in single photon counting mode.

  17. Heavy-ion induced desorption yields of cryogenic surfaces bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Evans, L; Kollmus, H; Küchler, D; Scrivens, R; Severin, D; Wengenroth, M; CERN. Geneva. ATS Department

    2011-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to study the dynamic outgassing of cryogenic surfaces. Two different targets, bare and goldcoated copper, were bombarded under perpendicular impact with 4.2 MeV/u Pb54+ ions. Partial pressure rises of H2, CH4, CO, and CO2 and effective desorption yields were measured at 300, 77, and 6.3 K using single shot and continuous ion bombardment techniques. We find that the heavy-ion-induced desorption yield is temperature dependent and investigate the influence of CO gas cryosorbed at 6.3 K. The gain in desorption yield reduction at cryogenic temperature vanishes after several monolayers of CO are cryosorbed on both targets. In this paper we describe the new cryogenic target assembly, the temperature-dependent pressure rise, desorption yield, and gas adsorption measurements.

  18. X-ray absorption and magnetic circular dichroism studies of ion-bombarded ferromagnet-antiferromagnet bilayers

    Science.gov (United States)

    Schmalhorst, J.; Sacher, M.; Höink, V.; Reiss, G.; Engel, D.; Ehresmann, A.

    2004-11-01

    The influence of He ion bombardment on the structural and magnetic interface properties of a polycrystalline Mn83Ir17/Co antiferromagnet-ferromagnet bilayer system is investigated. For annealed as well as for not annealed samples an exchange bias field of up to 200Oe is induced by the ion bombardment for doses up to 5×1014ions/cm2 . The x-ray absorption and the x-ray magnetic circular dichroism of Co and Mn is not significantly altered by this ion dose. For higher doses the exchange bias field is strongly reduced and accompanied by an increase of the ratio of the Mn to Co x-ray absorption intensities and a reduction of the Co x-ray magnetic circular dichroism signal. A model with a Gaussian-like intermixing zone at the AF/FM interface is developed to account for the observed changes of the x-ray absorption spectra.

  19. Collisional Cooling of Light Ions by Cotrapped Heavy Atoms.

    Science.gov (United States)

    Dutta, Sourav; Sawant, Rahul; Rangwala, S A

    2017-03-17

    We experimentally demonstrate cooling of trapped ions by collisions with cotrapped, higher-mass neutral atoms. It is shown that the lighter ^{39}K^{+} ions, created by ionizing ^{39}K atoms in a magneto-optical trap (MOT), when trapped in an ion trap and subsequently allowed to cool by collisions with ultracold, heavier ^{85}Rb atoms in a MOT, exhibit a longer trap lifetime than without the localized ^{85}Rb MOT atoms. A similar cooling of trapped ^{85}Rb^{+} ions by ultracold ^{133}Cs atoms in a MOT is also demonstrated in a different experimental configuration to validate this mechanism of ion cooling by localized and centered ultracold neutral atoms. Our results suggest that the cooling of ions by localized cold atoms holds for any mass ratio, thereby enabling studies on a wider class of atom-ion systems irrespective of their masses.

  20. Deep inelastic reactions of /sup 32/S on /sup 27/Al at 130 MeV bombarding energy

    Energy Technology Data Exchange (ETDEWEB)

    Manduchi, C.; Russo-Manduchi, M.T.; Segato, G.F.; Andolfato, F.

    1985-10-01

    Deep inelastic reactions induced by /sup 32/S bombardment on /sup 27/Al were studied at 130 MeV incident energy. The experiment employed a coincidence spectrometer consisting of two ion chambers which measured the energy, position and nuclear charge of the heavy reaction products. Inclusive fragment measurements and fragment-fragment coincidences have been used to determine the production of fragments of different Z, and related Q-value distributions. (orig.).

  1. Impact Characteristics of Different Rocks in a Pulsed Laser Irradiation Experiment: Simulation of Micrometeorite Bombardment on the Moon

    Science.gov (United States)

    Wu, Yanxue; Li, Xiongyao; Yao, Wenqing; Wang, Shijie

    2017-10-01

    Without the protection of the atmosphere, the soils on lunar surfaces undergo a series of optical, physical, and chemical changes during micrometeorite bombardment. To simulate the micrometeorite bombardment process and analyze the impact characteristics, four types of rocks, including terrestrial basalt and anorthosite supposed to represent lunar rock, an H-type chondrite (the Huaxi ordinary chondrite), and an iron meteorite (the Gebel Kamil iron meteorite) supposed to represent micrometeorite impactors, are irradiated by a nanosecond pulse laser in a high vacuum chamber. Based on laser irradiation experiments, the laser pits are found to be of different shapes and sizes which vary with the rock type. Many melt and vapor deposits are found on the mineral surfaces of all the samples, and nanophase iron (npFe) or Fe-Ni alloy particles are typically distributed on the surfaces of ilmenite, kamacite, or other minerals near kamacite. By analyzing the focused ion beam ultrathin slices of laser pits with a transmission electron microscope, the results show that the subsurface structures can be divided into three classes and that npFe can be easily found in Fe-bearing minerals. These differences in impact characteristics will help determine the source material of npFe and infer the type of micrometeorite impactors. During micrometeorite bombardment, in the mare regions, the npFe are probably produced simultaneously from lunar basalt and micrometeorites with iron-rich minerals, while the npFe in the highlands regions mainly come from micrometeorites.

  2. Photon counting imaging with an electron-bombarded CCD: Towards a parallel-processing photoelectronic time-to-amplitude converter

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M.; Jiggins, Stephen; Sergent, Nicolas; Zanda, Gianmarco; Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2014-12-15

    We have used an electron-bombarded CCD for optical photon counting imaging. The photon event pulse height distribution was found to be linearly dependent on the gain voltage. We propose on this basis that a gain voltage sweep during exposure in an electron-bombarded sensor would allow photon arrival time determination with sub-frame exposure time resolution. This effectively uses an electron-bombarded sensor as a parallel-processing photoelectronic time-to-amplitude converter, or a two-dimensional photon counting streak camera. Several applications that require timing of photon arrival, including Fluorescence Lifetime Imaging Microscopy, may benefit from such an approach. A simulation of a voltage sweep performed with experimental data collected with different acceleration voltages validates the principle of this approach. Moreover, photon event centroiding was performed and a hybrid 50% Gaussian/Centre of Gravity + 50% Hyperbolic cosine centroiding algorithm was found to yield the lowest fixed pattern noise. Finally, the camera was mounted on a fluorescence microscope to image F-actin filaments stained with the fluorescent dye Alexa 488 in fixed cells.

  3. Secondary ion emission from A sup I sup I sup I B sup V compound semiconductors under MeV-energy heavy ion bombardment

    CERN Document Server

    Ninomiya, S; Nagai, M; Nakata, Y; Imai, M; Imanishi, N

    2003-01-01

    Mass and yields of secondary ions emitted from GaP, GaAs, GaSb and InSb targets bombarded by MeV-energy heavy ion have been investigated. Obtained feature of the secondary ion emission depends characteristically on the target species. Molecular and small cluster ions were emitted from the GaP and GaAs targets. On the other hand, pretty large cluster ions were emitted from the GaSb and InSb targets. Yields of clusters from the GaSb target increase with increasing the incident energy and decrease exponentially with the cluster size, while yields from the InSb target keep constant or decrease gently with increasing the incident energy and show the power law dependence on the cluster size. These results show that cluster ions from the GaSb target are formed through a coagulation of small molecules emitted from the target in the selvage region near the surface, and those from the InSb target are emitted directly from the surface as cluster.

  4. Teach us atom structure

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Suh Yeon

    2006-08-15

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  5. Playing pinball with atoms.

    Science.gov (United States)

    Saedi, Amirmehdi; van Houselt, Arie; van Gastel, Raoul; Poelsema, Bene; Zandvliet, Harold J W

    2009-05-01

    We demonstrate the feasibility of controlling an atomic scale mechanical device by an external electrical signal. On a germanium substrate, a switching motion of pairs of atoms is induced by electrons that are directly injected into the atoms with a scanning tunneling microscope tip. By precisely controlling the tip current and distance we make two atom pairs behave like the flippers of an atomic-sized pinball machine. This atomic scale mechanical device exhibits six different configurations.

  6. Nanoscale mass conveyors

    Science.gov (United States)

    Regan, Brian C [Oakland, CA; Aloni, Shaul [Albany, CA; Zettl, Alexander K [Kensington, CA

    2008-03-11

    A mass transport method and device for individually delivering chargeable atoms or molecules from source particles is disclosed. It comprises a channel; at least one source particle of chargeable material fixed to the surface of the channel at a position along its length; a means of heating the channel; and a means for applying an controllable electric field along the channel, whereby the device transports the atoms or molecules along the channel in response to applied electric field. In a preferred embodiment, the mass transport device will comprise a multiwalled carbon nanotube (MWNT), although other one dimensional structures may also be used. The MWNT or other structure acts as a channel for individual or small collections of atoms due to the atomic smoothness of the material. Also preferred is a source particle of a metal such as indium. The particles move by dissociation into small units, in some cases, individual atoms. The particles are preferably less than 100 nm in size.

  7. Computer simulation of electronic excitation in atomic collision cascades

    Energy Technology Data Exchange (ETDEWEB)

    Duvenbeck, A.

    2007-04-05

    The impact of an keV atomic particle onto a solid surface initiates a complex sequence of collisions among target atoms in a near-surface region. The temporal and spatial evolution of this atomic collision cascade leads to the emission of particles from the surface - a process usually called sputtering. In modern surface analysis the so called SIMS technology uses the flux of sputtered particles as a source of information on the microscopical stoichiometric structure in the proximity of the bombarded surface spots. By laterally varying the bombarding spot on the surface, the entire target can be scanned and chemically analyzed. However, the particle detection, which bases upon deflection in electric fields, is limited to those species that leave the surface in an ionized state. Due to the fact that the ionized fraction of the total flux of sputtered atoms often only amounts to a few percent or even less, the detection is often hampered by rather low signals. Moreover, it is well known, that the ionization probability of emitted particles does not only depend on the elementary species, but also on the local environment from which a particle leaves the surface. Therefore, the measured signals for different sputtered species do not necessarily represent the stoichiometric composition of the sample. In the literature, this phenomenon is known as the Matrix Effect in SIMS. In order to circumvent this principal shortcoming of SIMS, the present thesis develops an alternative computer simulation concept, which treats the electronic energy losses of all moving atoms as excitation sources feeding energy into the electronic sub-system of the solid. The particle kinetics determining the excitation sources are delivered by classical molecular dynamics. The excitation energy calculations are combined with a diffusive transport model to describe the spread of excitation energy from the initial point of generation. Calculation results yield a space- and time-resolved excitation

  8. Ages of Martian basins and their implication for the end of the heavy bombardment

    Science.gov (United States)

    Werner, S. C.; Neukum, G.

    2003-04-01

    Global stratigraphic schemes for planetary bodies are usually based on the most common resurfacing process: the impacts of planetesimals which remain as craters or crater-related features on planetary surfaces. Through this random cratering process, counting of the accumulated number of impact craters on planetary surface units offers a valuable procedure in understanding the chronostratigraphy of a certain object. Recent ground-based observational data indicate a wavy (deviating from a simple power law) size-frequency distribution (SFD) for main belt and near-Earth asteroid populations. Neukum proposed a non-power law SFD for the lunar cratering record (Neukum and Ivanov, 1994). This SFD has kept its shape over a period of more than 4 Gyr. The lunar crater SFD is used to estimate the crater-generating family of projectiles from the lunar crater production function since the imagery of the Moon is the most complete and best investigated among the terrestrial planets. Two lunar crater production functions (PF's) were proposed by W. Hartmann (HPF) and G. Neukum (NPF) (Hartmann and Neukum, 2001). The maximum discrepancy between the HPF and NPF is roughly a factor of 3 for crater diameters near D=6 km. For diameters Dage of these surfaces. The major conclusion is that terrestrial planets are most probably bombarded by a single projectile source, i.e. bodies derived from the asteroid belt. The current understanding of Mars's geologic history is based mainly on crater size-frequency measurements carried out on high-resolution Viking imagery and on an impact chronology model for Mars estimated from observations of planet-crossing asteroids and scaled by the lunar production function, which is the best investigated among terrestrial body surfaces. The similarity to crater size-frequency distributions found in the inner solar system suggests a similar origin of the projectiles, probably mainly stemming from the asteroid belt, and the impact rate Mars has had a lunar

  9. Giant comets and mass extinctions of life

    Science.gov (United States)

    Napier, W. M.

    2015-03-01

    I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating accuracy of the craters. Their amplitudes and frequency are inconsistent with an origin in asteroid breakups or Oort cloud disturbances, but are consistent with the arrival and disintegration in near-Earth orbits of rare, giant comets, mainly in transit from the Centaur population into the Jupiter family and Encke regions. About 1 in 10 Centaurs in Chiron-like orbits enter Earth-crossing epochs, usually repeatedly, each such epoch being generally of a few thousand years' duration. On time-scales of geological interest, debris from their breakup may increase the mass of the near-Earth interplanetary environment by two or three orders of magnitude, yielding repeated episodes of bombardment and stratospheric dusting. I find a strong correlation between these bombardment episodes and major biostratigraphic and geological boundaries, and propose that episodes of extinction are most effectively driven by prolonged encounters with meteoroid streams during bombardment episodes. Possible mechanisms are discussed.

  10. An Archaean heavy bombardment from a destabilized extension of the asteroid belt.

    Science.gov (United States)

    Bottke, William F; Vokrouhlický, David; Minton, David; Nesvorný, David; Morbidelli, Alessandro; Brasser, Ramon; Simonson, Bruce; Levison, Harold F

    2012-05-03

    The barrage of comets and asteroids that produced many young lunar basins (craters over 300 kilometres in diameter) has frequently been called the Late Heavy Bombardment (LHB). Many assume the LHB ended about 3.7 to 3.8 billion years (Gyr) ago with the formation of Orientale basin. Evidence for LHB-sized blasts on Earth, however, extend into the Archaean and early Proterozoic eons, in the form of impact spherule beds: globally distributed ejecta layers created by Chicxulub-sized or larger cratering events4. At least seven spherule beds have been found that formed between 3.23 and 3.47 Gyr ago, four between 2.49 and 2.63 Gyr ago, and one between 1.7 and 2.1 Gyr ago. Here we report that the LHB lasted much longer than previously thought, with most late impactors coming from the E belt, an extended and now largely extinct portion of the asteroid belt between 1.7 and 2.1 astronomical units from Earth. This region was destabilized by late giant planet migration. E-belt survivors now make up the high-inclination Hungaria asteroids. Scaling from the observed Hungaria asteroids, we find that E-belt projectiles made about ten lunar basins between 3.7 and 4.1 Gyr ago. They also produced about 15 terrestrial basins between 2.5 and 3.7 Gyr ago, as well as around 70 and four Chicxulub-sized or larger craters on the Earth and Moon, respectively, between 1.7 and 3.7 Gyr ago. These rates reproduce impact spherule bed and lunar crater constraints.

  11. Control the fear atomic

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Gwan [I and Book, Seoul (Korea, Republic of)

    2003-04-15

    This book has a lot of explanation of nuclear energy with articles. Their titles are the bad man likes atomic, the secret of atom, nuclear explosion, NPT?, the secret of uranium fuel rod, nuclear power plant vs nuclear bomb, I hate atomic, keep plutonium in control, atomic in peace and find out alternative energy.

  12. STANDARD ATOMIC WEIGHT VALUES FOR THE MONONUCLIDIC ELEMENTS - 2005.

    Energy Technology Data Exchange (ETDEWEB)

    HOLDEN, N.E.

    2005-08-13

    When the policy for determining the atomic weight values for the mononuclidic elements was changed some decades ago, it was argued that new atomic mass tables would only be produced about once a decade. Since 1977, the average has been once every nine years, which is consistent with that early estimate. This report summarizes the changes over the years for the atomic weight values of the mononuclidic elements. It applies the Commission's technical rules to the latest atomic mass table and recommends changes in the values of the Standard Atomic Weights for eleven of the twenty-two for the TSAW.

  13. Comparison of the applicability of mass spectrometer ion sources using a polarity- molecular weight scattergram with a 600 sample in-house chemical library.

    Science.gov (United States)

    Sugimura, Natsuhiko; Furuya, Asami; Yatsu, Takahiro; Shibue, Toshimichi

    2015-01-01

    To provide a practical guideline for the selection of a mass spectrometer ion source, we compared the applicability of three types of ion source: direct analysis in real time (DART), electrospray ionization (ESI) and fast atom bombardment (FAB), using an in-house high-resolution mass spectrometry sample library consisting of approximately 600 compounds. The great majority of the compounds (92%), whose molecular weights (MWs) were broadly distributed between 150 and 1000, were detected using all the ion sources. Nevertheless, some compounds were not detected using specific ion sources. The use of FAB resulted in the highest sample detection rate (>98%), whereas the detection rates obtained using DART and ESI were slightly lower (>96%). A scattergram constructed using MW and topological polar surface area (tPSA) as a substitute for molecular polarity showed that the performance of ESI was weak in the low-MW (800) area. These results might provide guidelines for the selection of ion sources for inexperienced mass spectrometry users.

  14. Measurements of production cross sections of {sup 10}Be and {sup 26}Al by 120 GeV and 392 MeV proton bombardment of {sup 89}Y, {sup 159}Tb, and {sup nat}Cu targets

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, S.; Okumura, S.; Yashima, H. [Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494 (Japan); Matsushi, Y. [Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto 611-0011 (Japan); Matsuzaki, H. [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, Bunkyo, Tokyo 113-0032 (Japan); Matsumura, H.; Toyoda, A. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Oishi, K. [Shimizu Corporation, Ecchujima, Tokyo 135-8530 (Japan); Matsuda, N.; Kasugai, Y. [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Sakamoto, Y. [ATOX Co., Ltd., Kashiwa, Chiba 277-0861 (Japan); Nakashima, H. [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Boehnlein, D.; Coleman, R.; Lauten, G.; Leveling, A.; Mokhov, N.; Ramberg, E.; Soha, A.; Vaziri, K. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); and others

    2015-10-15

    The production cross sections of {sup 10}Be and {sup 26}Al were measured by accelerator mass spectrometry using {sup 89}Y, {sup 159}Tb, and {sup nat}Cu targets bombarded by protons with energies E{sub p} of 120 GeV and 392 MeV. The production cross sections obtained for {sup 10}Be and {sup 26}Al were compared with those previously reported using E{sub p} = 50 MeV–24 GeV and various targets. It was found that the production cross sections of {sup 10}Be monotonically increased with increasing target mass number when the proton energy was greater than a few GeV. On the other hand, it was also found that the production cross sections of {sup 10}Be decreased as the target mass number increased from that of carbon to those near the mass numbers of nickel and zinc when the proton energy was below approximately 1 GeV. They also increased as the target mass number increased from near those of nickel and zinc to that of bismuth, in the same proton energy range. Similar results were observed in the production cross sections of {sup 26}Al, though the absolute values were quite different between {sup 10}Be and {sup 26}Al. The difference between these production cross sections may depend on the impact parameter (nuclear radius) and/or the target nucleus stiffness.

  15. SMART-1 highlights and relevant studies on early bombardment and geological processes on rocky planets

    Energy Technology Data Exchange (ETDEWEB)

    Foing, B H; Koschny, D; Frew, D; Almeida, M; Zender, J; Heather, D; Peters, S [ESA Research and Scientific Support Department, ESTEC/SCI-S, Postbus 299, 10 ESA Noordwijk (Netherlands); Racca, G D; Marini, A; Stagnaro, L [ESA Scientific Project Department, ESTEC/SCI-PD, Postbus 299, 10 ESA Noordwijk (Netherlands); Josset, J L [Space-X, Space Exploration Institute, Rue Jacquet Droz 1, CH 2007 Neuchatel (Switzerland); Beauvivre, S [Micro-Cameras SA, Neuchatel, Puits-godet 10a, CH-2000 Neuchatel (Switzerland); Grande, M [University of Wales, Aberystwyth, SY23 3BZ (United Kingdom); Kellett, B [Rutherford Appleton Labs, Harwell Science and Innovation Campus, Didcot, OX11 0QX (United Kingdom); Huovelin, J [Finnish Meteorology Institute, Helsinki International Airport, Helsinki (Finland); Nathues, A; Mall, U [Max-Planck-Institute for Solar System Research, Lindau (Germany); Ehrenfreund, P [Leiden University, PO Box 9500, 2300 RA Leiden (Netherlands); McCannon, P [ESA Directorate of Technology, ESTEC/TEC, 10 ESA Noordwjik (Netherlands)], E-mail: Bernard.Foing@esa.int

    2008-08-15

    lunar resources. We present here SMART-1 results relevant to the study of the early bombardment and geological processes on rocky planets. Further information and updates on the SMART-1 mission can be found on the ESA Science and Technology web pages, at: http://sci.esa.int/smart-1/.

  16. Post-Hadean transitions in Jack Hills zircon provenance: A signal of the Late Heavy Bombardment?

    Science.gov (United States)

    Bell, Elizabeth A.; Harrison, T. Mark

    2013-02-01

    system (i.e., Late Heavy Bombardment; 3.95-3.85) may have causal significance.

  17. The fate of meteoric metals in ice particles: Effects of sublimation and energetic particle bombardment

    Science.gov (United States)

    Mangan, T. P.; Frankland, V. L.; Murray, B. J.; Plane, J. M. C.

    2017-08-01

    The uptake and potential reactivity of metal atoms on water ice can be an important process in planetary atmospheres and on icy bodies in the interplanetary and interstellar medium. For instance, metal atom uptake affects the gas-phase chemistry of the Earth's mesosphere, and has been proposed to influence the agglomeration of matter into planets in protoplanetary disks. In this study the fate of Mg and K atoms incorporated into water-ice films, prepared under ultra-high vacuum conditions at temperatures of 110-140 K, was investigated. Temperature-programmed desorption experiments reveal that Mg- and K-containing species do not co-desorb when the ice sublimates, demonstrating that uptake on ice particles causes irreversible removal of the metals from the gas phase. This implies that uptake on ice particles in terrestrial polar mesospheric clouds accelerates the formation of large meteoric smoke particles (≥1 nm radius above 80 km) following sublimation of the ice. Energetic sputtering of metal-dosed ice layers by 500 eV Ar+ and Kr+ ions shows that whereas K reacts on (or within) the ice surface to form KOH, adsorbed Mg atoms are chemically inert. These experimental results are consistent with electronic structure calculations of the metals bound to an ice surface, where theoretical adsorption energies on ice are calculated to be -68 kJ mol-1 for K, -91 kJ mol-1 for Mg, and -306 kJ mol-1 for Fe. K can also insert into a surface H2O to produce KOH and a dangling H atom, in a reaction that is slightly exothermic.

  18. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  19. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  20. The Formation of Formaldehyde on Interstellar Carbonaceous Grain Analogs by O/H Atom Addition

    Science.gov (United States)

    Potapov, Alexey; Jäger, Cornelia; Henning, Thomas; Jonusas, Mindaugas; Krim, Lahouari

    2017-09-01

    An understanding of possible scenarios for the formation of astrophysically relevant molecules, particularly complex organic molecules, will bring us one step closer to the understanding of our astrochemical heritage. In this context, formaldehyde is an important molecule as a precursor of methanol, which in turn is a starting point for the formation of more complex organic species. In the present experiments, for the first time, following the synthesis of CO, formaldehyde has been produced on the surface of interstellar grain analogs, hydrogenated fullerene-like carbon grains, by O and H atom bombardment. The formation of H2CO is an indication for a possible methanol formation route in such systems.

  1. AN ANTHOLOGY OF THE DISTINGUISHED ACHIEVEMENTS IN SCIENCE AND TECHNIQUE. PART 40: THE SCIENTIFIC OPENING OF THE METHOD OF EXPLOSIVE IMPLOSION FOR THE OBTAINING ABOVE CRITICAL MASS OF NUCLEAR CHARGE AND UKRAINIAN «TRACK» IN THE «MANHATTAN» AMERICAN ATOMIC

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2017-10-01

    Full Text Available Purpose. Preparation of short scientifically-historical essay about the prominent American scientist-chemist and physicist George Bogdan Kistiakowsky, having the Ukrainian «roots» and bringing in a considerable scientific and technical contribution to development and creation of the first atomic bombs in the USA. Methodology. Scientific methods of collection, analysis and analytical treatment of the opened scientific and technical information of world level in area of atomic and nuclear physics, physics of hyperpessure, applied electrophysics, modern experimental physics, atomic science and technology. Results. The state-of-the-art review of the state of basic scientific and technical problems, arising up before scientists and engineers at development and creation within the framework of the «Manhattan» American atomic project of the first standards of atomic bombs of the USA is resulted. Two basic methods of receipt in the a-bomb of above critical mass of the divided nuclear material of military load are described: method of «cannon-shot» and method of «explosive implosion». Basic information is resulted about the declassified scheme and construction decisions, applied scientists and specialists in the first atomic bombs of the USA. Technical information is indicated about basic ordinary hard chemical explosive matters (EM, atomic bombs of the USA of implosend type utillized in the first. Originality. Systematization of the scientific and technical materials devoted the basic results of pioneer nuclear researches in the USA and USSR in the period of 1940-th on a capture above all things for soldiery aims by intranuclear energy and to the offensive on a planet Earth of nuclear era known from the opened sources is executed. The important role of the scientific ukrainian origin of G.B. Kistiakowsky in development and creation in the National nuclear center of the USA − Los-Alamos of laboratory of the first implosend atomic bombs of the

  2. Gravitational Wave Detection with Atom Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Savas; /Stanford U., Phys. Dept.; Graham, Peter W.; /SLAC /Stanford U., Phys. Dept.; Hogan, Jason M.; Kasevich, Mark A.; /Stanford U., Phys. Dept.; Rajendran, Surjeet; /SLAC /Stanford U., Phys. Dept.

    2008-01-23

    We propose two distinct atom interferometer gravitational wave detectors, one terrestrial and another satellite-based, utilizing the core technology of the Stanford 10m atom interferometer presently under construction. The terrestrial experiment can operate with strain sensitivity {approx} 10{sup -19}/{radical}Hz in the 1 Hz-10 Hz band, inaccessible to LIGO, and can detect gravitational waves from solar mass binaries out to megaparsec distances. The satellite experiment probes the same frequency spectrum as LISA with better strain sensitivity {approx} 10{sup -20}/{radical}Hz. Each configuration compares two widely separated atom interferometers run using common lasers. The effect of the gravitational waves on the propagating laser field produces the main effect in this configuration and enables a large enhancement in the gravitational wave signal while significantly suppressing many backgrounds. The use of ballistic atoms (instead of mirrors) as inertial test masses improves systematics coming from vibrations and acceleration noise, and reduces spacecraft control requirements.

  3. Atomic vapor density monitor

    Energy Technology Data Exchange (ETDEWEB)

    Sewall, N.; Harris, W.; Beeler, R.; Wooldridge, J.; Chen, H.L.

    1986-09-01

    This report presents information on the Atomic Vapor Density Monitor (AVDM) system that measures the density of a vapor by measuring the absorption of light from a swept-wavelength laser that passes through an atomic vapor stream.

  4. Gene transfer by particle bombardment to embryogenic cultures of Picea abies and the production of transgenic plantlets

    Energy Technology Data Exchange (ETDEWEB)

    Clapham, David; Elfstrand, Malin; Sabala, Izabela; Arnold, Sara von [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Genetics; Demel, Petra; Koop, H.U. [Muenchen Univ., Muenchen (Germany). Botanisches Institut

    2000-07-01

    A particle inflow gun enabled efficient production of transgenic plantlets of Picea abies from embryogenic suspension cultures. In transient assays, the Zea ubiquitin promoter was 12-16 times as active as the 35S promoter. For stable transformation, the plasmid pAHC25 contained the bar gene and the gusA gene, both driven by the Zea ubiquitin promoter. Cells were maintained from 1 to 3 h before bombardment on proliferation medium supplemented with 0.25 M myoinositol and, from day 8, supplemented with Basta as selective agent. Embryogenic colonies resistant to Basta appeared from two months after bombardment. Of over 100 independent Basta-resistant sublines tested, 65% expressed the co-transformed reporter gene, even when it was not linked to the selectable marker. Over 80% of the sublines retained their embryogenic potential. Of 11 transformants analyzed, 4 contained transgenes in low copy number (1-3), the rest contained transgenes in up to 15-20 copies. Over 200 Basta-resistant sublines from four cell lines have been established, of which 138 are confirmed as transformed. Plantlets have been regenerated and grown on in pots.

  5. Particle Simulations of a Thermionic RF Gun with Gridded Triode Structure for Reduction of Back-Bombardment

    CERN Document Server

    Kusukame, K; Kii, T; Masuda, K; Nakai, Y; Ohgaki, H; Yamazaki, T; Yoshikawa, K; Zen, H

    2005-01-01

    Thermionic RF guns show advantageous features compared with photocathode ones such as easy operation and much higher repetition rate of micropulses, both of which are suitable for their application to high average power FELs. They however suffer from the back-bombardment effect [1], i.e., in conventional RF guns, electrons are extracted from cathode also in the latter half of accelerating phase and tend to back-stream to hit the cathode, and as a result the macropulse duration is limited down to severalμsec Against this adverse effect in thermionic RF guns, introduction of the triode structure has been proposed [2], where the accelerating phase and amplitude nearby the cathode can be controlled regardless of the phase of the first accelerating cell in the conventional RF gun. Our one-dimensional particle simulation results predict that the back-bombardment power can be reduced by 99 % only with 30-40 kW RF power fed to the grid in the present triode structure with an optimal phase difference from th...

  6. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  7. Playing Pinball with Atoms

    NARCIS (Netherlands)

    Saedi, A.; van Houselt, Arie; van Gastel, Raoul; Poelsema, Bene; Zandvliet, Henricus J.W.

    2009-01-01

    We demonstrate the feasibility of controlling an atomic scale mechanical device by an external electrical signal. On a germanium substrate, a switching motion of pairs of atoms is induced by electrons that are directly injected into the atoms with a scanning tunneling microscope tip. By precisely

  8. Atomization characteristics of a prefilming airblast atomizer

    Science.gov (United States)

    Hayashi, Shigeru; Koito, Atsushi; Hishiki, Manabu

    1992-01-01

    The size distribution of water test sprays generated by a prefilming airblast atomizer used for aeroengines was measured in swirling and non-swirling flows with the well established laser scattering particle sizing technique. Atomizing air velocity (or pressure difference) was varied in a range wider than the conditions of actual engines. The Sauter Mean Diameter (SMD) decreased at approximately a 1.5 power of the atomizing air velocity, being a higher velocity index than the previously reported values of 1 to 1.2. It was unexpectedly found that the effect of the liquid/air flow ratio was small. Since swirling flow increased the SMD at lower air velocities yet decreased it at higher ones, it is suggested that the reverse flow near the nozzle pintle adversely affects atomization.

  9. Suprathermal oxygen atoms in the Martian upper atmosphere: Contribution of the proton and hydrogen atom precipitation

    Science.gov (United States)

    Shematovich, V. I.

    2017-07-01

    This is a study of the kinetics and transport of hot oxygen atoms in the transition region (from the thermosphere to the exosphere) of the Martian upper atmosphere. It is assumed that the source of the hot oxygen atoms is the transfer of momentum and energy in elastic collisions between thermal atmospheric oxygen atoms and the high-energy protons and hydrogen atoms precipitating onto the Martian upper atmosphere from the solar-wind plasma. The distribution functions of suprathermal oxygen atoms by the kinetic energy are calculated. It is shown that the exosphere is populated by a large number of suprathermal oxygen atoms with kinetic energies up to the escape energy 2 eV; i.e., a hot oxygen corona is formed around Mars. The transfer of energy from the precipitating solar-wind plasma protons and hydrogen atoms to the thermal oxygen atoms leads to the formation of an additional nonthermal escape flux of atomic oxygen from the Martian atmosphere. The precipitation-induced escape flux of hot oxygen atoms may become dominant under the conditions of extreme solar events, such as solar flares and coronal mass ejections, as shown by recent observations onboard NASA's MAVEN spacecraft (Jakosky et al., 2015).

  10. Single atom electrochemical and atomic analytics

    Science.gov (United States)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  11. Multilevel Atomic Coherent States and Atomic Holomorphic Representation

    Science.gov (United States)

    Cao, Chang-Qi; Haake, Fritz

    1996-01-01

    The notion of atomic coherent states is extended to the case of multilevel atom collective. Based on atomic coherent states, a holomorphic representation for atom collective states and operators is defined. An example is given to illustrate its application.

  12. Observation of $\\pi^- K^+$ and $\\pi^+ K^-$ atoms

    CERN Document Server

    Adeva, B; The PS212 collaboration; Allkofer, Y.; Amsler, C.; Anania, A.; Aogaki, S.; Benelli, A.; Brekhovskikh, V.; Cechak, T.; Chiba, M.; Chliapnikov, P.; Doskarova, P.; Drijard, D.; Dudarev, A.; Dumitriu, D.; Fluerasu, D.; Gorin, A.; Gorchakov, O.; Gritsay, K.; Guaraldo, C.; Gugiu, M.; Hansroul, M.; Hons, Z.; Horikawa, S.; Iwashita, Y.; Karpukhin, V.; Kluson, J.; Kobayashi, M.; Kruglov, V.; Kruglova, L.; Kulikov, A.; Kulish, E.; Kuptsov, A.; Lamberto, A.; Lanaro, A.; Lednicky, R.; Marinas, C.; Martincik, J.; Nikitin, M.; Okada, K.; Olchevskii, V.; Pentia, M.; Penzo, A.; Plo, M.; Prusa, P.; Rappazzo, G.; Vidal, A.Romero; Ryazantsev, A.; Rykalin, V.; Saborido, J.; Sidorov, A.; Smolik, J.; Takeutchi, F.; Tauscher, L.; Trojek, T.; Trusov, S.; Urban, T.; Vrba, T.; Yazkov, V.; Yoshimura, Y.; Zhabitsky, M.; Zrelov, P.

    2016-01-01

    The observation of hydrogen-like $\\pi K$ atoms, consisting of $\\pi^- K^+$ or $\\pi^+ K^-$ mesons, is presented. The atoms have been produced by 24 GeV/$c$ protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionisation) of $\\pi K$ atoms in the same targets yields characteristic $\\pi K$ pairs, called ``atomic pairs'', with small relative momenta in the pair centre-of-mass system. The upgraded DIRAC experiment has observed $349\\pm62$ such atomic $\\pi K$ pairs, corresponding to a signal of 5.6 standard deviations.

  13. Evaluation of computational models and cross sections used by MCNP6 for simulation of characteristic X-ray emission from thick targets bombarded by kiloelectronvolt electrons

    Energy Technology Data Exchange (ETDEWEB)

    Poškus, A., E-mail: andrius.poskus@ff.vu.lt

    2016-09-15

    This paper evaluates the accuracy of the single-event (SE) and condensed-history (CH) models of electron transport in MCNP6.1 when simulating characteristic K{sub α}, total K (=K{sub α} + K{sub β}) and L{sub α} X-ray emission from thick targets bombarded by electrons with energies from 5 keV to 30 keV. It is shown that the MCNP6.1 implementation of the CH model for the K-shell impact ionization leads to underestimation of the K yield by 40% or more for the elements with atomic numbers Z < 15 and overestimation of the K{sub α} yield by more than 40% for the elements with Z > 25. The L{sub α} yields are underestimated by more than an order of magnitude in CH mode, because MCNP6.1 neglects X-ray emission caused by electron-impact ionization of L, M and higher shells in CH mode (the L{sub α} yields calculated in CH mode reflect only X-ray fluorescence, which is mainly caused by photoelectric absorption of bremsstrahlung photons). The X-ray yields calculated by MCNP6.1 in SE mode (using ENDF/B-VII.1 library data) are more accurate: the differences of the calculated and experimental K yields are within the experimental uncertainties for the elements C, Al and Si, and the calculated K{sub α} yields are typically underestimated by (20–30)% for the elements with Z > 25, whereas the L{sub α} yields are underestimated by (60–70)% for the elements with Z > 49. It is also shown that agreement of the experimental X-ray yields with those calculated in SE mode is additionally improved by replacing the ENDF/B inner-shell electron-impact ionization cross sections with the set of cross sections obtained from the distorted-wave Born approximation (DWBA), which are also used in the PENELOPE code system. The latter replacement causes a decrease of the average relative difference of the experimental X-ray yields and the simulation results obtained in SE mode to approximately 10%, which is similar to accuracy achieved with PENELOPE. This confirms that the DWBA inner

  14. Electric propulsion. [pulsed plasma thruster and electron bombardment ion engine for MSAT attitude control and stationkeeping

    Science.gov (United States)

    1982-01-01

    An alternative propulsion subsystem for MSAT is presented which has a potential of reducing the satellite weight by more than 15%. The characteristics of pulsed plasma and ion engines are described and used to estimate of the mass of the propellant and thrusters for attitude control and stationkeeping functions for MSAT. Preliminary estimates indicate that the electric propulsion systems could also replace the large momentum wheels necessary to counteract the solar pressure; however, the fine pointing wheels would be retained. Estimates also show that either electric propulsion system can save approximately 18% to 20% of the initial 4,000 kg mass. The issues that require further experimentation are mentioned.

  15. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    Cvitas, Marko T.; Soldan, Pavel; Hutson, Jeremy M.

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  16. Tungsten oxide thin film bombarded with a low energy He ion beam: evidence for a reduced erosion and W enrichment

    Science.gov (United States)

    Martin, C.; Hijazi, H.; Addab, Y.; Domenichini, B.; Bannister, M. E.; Meyer, F. W.; Pardanaud, C.; Giacometti, G.; Cabié, M.; Roubin, P.

    2017-12-01

    Nanocrystalline tungsten oxide (WO3) thin films synthesized by thermal oxidation of tungsten substrates were exposed to low energy helium ions (energy: 80 eV; flux: 1.4-1.7 × 1020 m-2 s-1) at room temperature and at 673 K. The structure and morphology changes of the oxide were studied using Raman spectroscopy and electron microscopy. Due to the low ion energy, no erosion is observed at room temperature. In contrast, at 673 K, a color change is observed and a significant erosion is measured (˜70 nm for a fluence of ˜4 × 1021 m-2) due to a synergetic effect between ion bombardment and heating. We show that erosion processes and structural changes strongly depend on the ion fluence and in particular the higher the fluence, the lower the erosion yield, most likely due to oxygen depletion in the oxide near-surface layers.

  17. Modern atomic physics

    CERN Document Server

    Natarajan, Vasant

    2015-01-01

    Much of our understanding of physics in the last 30-plus years has come from research on atoms, photons, and their interactions. Collecting information previously scattered throughout the literature, Modern Atomic Physics provides students with one unified guide to contemporary developments in the field. After reviewing metrology and preliminary material, the text explains core areas of atomic physics. Important topics discussed include the spontaneous emission of radiation, stimulated transitions and the properties of gas, the physics and applications of resonance fluorescence, coherence, cooling and trapping of charged and neutral particles, and atomic beam magnetic resonance experiments. Covering standards, a different way of looking at a photon, stimulated radiation, and frequency combs, the appendices avoid jargon and use historical notes and personal anecdotes to make the topics accessible to non-atomic physics students. Written by a leader in atomic and optical physics, this text gives a state-of-the...

  18. Single atom microscopy.

    Science.gov (United States)

    Zhou, Wu; Oxley, Mark P; Lupini, Andrew R; Krivanek, Ondrej L; Pennycook, Stephen J; Idrobo, Juan-Carlos

    2012-12-01

    We show that aberration-corrected scanning transmission electron microscopy operating at low accelerating voltages is able to analyze, simultaneously and with single atom resolution and sensitivity, the local atomic configuration, chemical identities, and optical response at point defect sites in monolayer graphene. Sequential fast-scan annular dark-field (ADF) imaging provides direct visualization of point defect diffusion within the graphene lattice, with all atoms clearly resolved and identified via quantitative image analysis. Summing multiple ADF frames of stationary defects produce images with minimized statistical noise and reduced distortions of atomic positions. Electron energy-loss spectrum imaging of single atoms allows the delocalization of inelastic scattering to be quantified, and full quantum mechanical calculations are able to describe the delocalization effect with good accuracy. These capabilities open new opportunities to probe the defect structure, defect dynamics, and local optical properties in 2D materials with single atom sensitivity.

  19. Defect production and annihilation in metals through electronic excitation by energetic heavy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwase, Akihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Defect production, radiation annealing and defect recovery are studied in Ni and Cu irradiated with low-energy ({approx}1-MeV) and high-energy ({approx}100-MeV) ions. Irradiation of Ni with {approx}100-MeV ions causes an anomalous reduction, or even a complete disappearance of the stage-I recovery. This result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of the stage-I interstitials. This effect is also observed in Ni as a large radiation annealing during 100-MeV heavy ion irradiation. On the other hand, in Cu thin foils, we find the defect production process strongly associated with electron excitation, where the defect production cross section is nearly proportional to S{sub e}{sup 2}. (author)

  20. Solar Spectroscopy: Atomic Processes

    Science.gov (United States)

    Mason, H.; Murdin, P.

    2000-11-01

    A Greek philosopher called DEMOCRITUS (c. 460-370 BC) first introduced the concept of atoms (which means indivisible). His atoms do not precisely correspond to our atoms of today, which are not indivisible, but made up of a nucleus (protons with positive charge and neutrons which have no charge) and orbiting electrons (with negative charge). Indeed, in the solar atmosphere, the temperature is suc...

  1. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  2. The 30Si (ρ, γ) 31P reaction for bombarding energies between 1.00 and 1.53 MeV

    NARCIS (Netherlands)

    Rinsvelt, H. van; Smith, Philip B.

    Eighteen resonances have been identified as belonging to the 30Si(, γ)31P reaction for proton bombarding energies between 1.00 and 1.53 MeV. The gamma-ray yield of the corresponding excited states of 31P has been measured, and the principle features of the decay have been determined. Double and/or

  3. The influence of energetic bombardment on the structure formation of sputtered zinc oxide films. Development of an atomistic growth model and its application to tailor thin film properties

    Energy Technology Data Exchange (ETDEWEB)

    Koehl, Dominik

    2011-02-17

    The focus of this work is the investigation of the growth of zinc oxide (ZnO) thin films. It is demonstrated that with a modified, ion beam assisted sputtering (IBAS) process, zinc oxide films can be deposited which exhibit a markedly improved crystalline order. Furthermore, it is demonstrated that intense energetic oxygen ion bombardment can be utilized to change film texture from the typical (002)-self-texture to an a-axis texture where the (002)-planes are perpendicular to the substrate surface. An understanding of the underlying mechanisms is developed which also facilitates a more detailed understanding of the action of ion bombardment during zinc oxide film growth. It is shown that zinc oxide films are susceptible to the influence of ion bombardment particularly in the nucleation regime of growth and that this finding is generally true for all observed structural changes induced by ion bombardment with various species, energies and flux densities. It is demonstrated not only that the initial growth stage plays an important role in the formation of a preferred growth orientation but also that the action of texture forming mechanisms in subsequent growth stages is comparatively weak. (orig.)

  4. "I Feel like I'm Being Hit from All Directions": Enduring the Bombardment as a Mature-Age Learner Returning to Formal Learning

    Science.gov (United States)

    Willans, Julie; Seary, Karen

    2011-01-01

    The mature-age learner's re-engagement with a formal learning environment may be somewhat akin to the novice Paintball player who, unless well positioned and attuned to the rules of the combative game, is bombarded and worn down by constant "hits". For the mature-age learner, such "hits" may come in the form of tensions…

  5. Atomic Inference from Weak Gravitational Lensing Data

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Phil; /KIPAC, Menlo Park

    2005-12-14

    We present a novel approach to reconstructing the projected mass distribution from the sparse and noisy weak gravitational lensing shear data. The reconstructions are regularized via the knowledge gained from numerical simulations of clusters, with trial mass distributions constructed from n NFW profile ellipsoidal components. The parameters of these ''atoms'' are distributed a priori as in the simulated clusters. Sampling the mass distributions from the atom parameter probability density function allows estimates of the properties of the mass distribution to be generated, with error bars. The appropriate number of atoms is inferred from the data itself via the Bayesian evidence, and is typically found to be small, reecting the quality of the data. Ensemble average mass maps are found to be robust to the details of the noise realization, and succeed in recovering the demonstration input mass distribution (from a realistic simulated cluster) over a wide range of scales. As an application of such a reliable mapping algorithm, we comment on the residuals of the reconstruction and the implications for predicting convergence and shear at specific points on the sky.

  6. K$_{-}$ and K$_{-}$ polarizability from kaonic atoms

    CERN Document Server

    Backenstoss, Gerhard; Bergström, I; Bunaciu, T; Egger, J; Hagelberg, R; Hultberg, S; Koch, H; Lynen, Y; Ritter, H G; Schwitter, A; Tauscher, L

    1973-01-01

    The K/sup -/ mass was determined from kaonic atomic X-rays from Au and Ba to be 493.691+or-0.040 MeV. An upper limit for the polarizability of the K/sup -/ was found to be 0.020 fm/sup 3/ at 90% confidence. (18 refs).

  7. Atomic lithium vapor laser isotope separation

    CERN Document Server

    Olivares, I E

    2002-01-01

    An atomic vapor laser isotope separation in lithium was performed using tunable diode lasers. The method permits also the separation of the isotopes between the sup 6 LiD sub 2 and the sup 7 LiD sub 1 lines using a self-made mass separator which includes a magnetic sector and an ion beam designed for lithium. (Author)

  8. Asteroid bombardment and the core of Theia as possible sources for the Earth's late veneer component

    Science.gov (United States)

    Sleep, Norman H.

    2016-07-01

    The silicate Earth contains Pt-group elements in roughly chondritic relative ratios, but with absolute concentrations veneer implies addition of chondrite-like material with 0.3-0.7% mass of the Earth's mantle or an equivalent planet-wide thickness of 5-20 km. The veneer thickness, 200-300 m, within the lunar crust and mantle is much less. One hypothesis is that the terrestrial veneer arrived after the moon-forming impact within a few large asteroids that happened to miss the smaller Moon. Alternatively, most of terrestrial veneer came from the core of the moon-forming impactor, Theia. The Moon then likely contains iron from Theia's core. Mass balances lend plausibility. The lunar core mass is ˜1.6 × 1021 kg and the excess FeO component in the lunar mantle is 1.3-3.5 × 1021 kg as Fe, totaling 3-5 × 1021 kg or a few percent of Theia's core. This mass is comparable to the excess Fe of 2.3-10 × 1021 kg in the Earth's mantle inferred from the veneer component. Chemically in this hypothesis, Fe metal from Theia's core entered the Moon-forming disk. H2O and Fe2O3 in the disk oxidized part of the Fe, leaving the lunar mantle near a Fe-FeO buffer. The remaining iron metal condensed, gathered Pt-group elements eventually into the lunar core. The silicate Moon is strongly depleted in Pt-group elements. In contrast, the Earth's mantle contained excess oxidants, H2O and Fe2O3, which quantitatively oxidized the admixed Fe from Theia's core, retaining Pt-group elements. In this hypothesis, asteroid impacts were relatively benign with ˜1 terrestrial event that left only thermophile survivors.

  9. High efficiency direct detection of ions from resonance ionization of sputtered atoms

    Science.gov (United States)

    Gruen, Dieter M.; Pellin, Michael J.; Young, Charles E.

    1986-01-01

    A method and apparatus are provided for trace and other quantitative analysis with high efficiency of a component in a sample, with the analysis involving the removal by ion or other bombardment of a small quantity of ion and neutral atom groups from the sample, the conversion of selected neutral atom groups to photoions by laser initiated resonance ionization spectroscopy, the selective deflection of the photoions for separation from original ion group emanating from the sample, and the detection of the photoions as a measure of the quantity of the component. In some embodiments, the original ion group is accelerated prior to the RIS step for separation purposes. Noise and other interference are reduced by shielding the detector from primary and secondary ions and deflecting the photoions sufficiently to avoid the primary and secondary ions.

  10. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  11. Atoms, Molecules and Radiation

    Indian Academy of Sciences (India)

    IAS Admin

    A Refresher Course in Applications of Quantum Mechanics to 'Atoms, Molecules and Radiation' will be held at the Indian Academy of Sciences, Bangalore from December 8 to 20. 2014. The Course is primarily aimed at teachers teaching quantum mechanics and/ or atomic and molecular physics at the UG / PG level.

  12. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  13. Atomicity in Electronic Commerce,

    Science.gov (United States)

    1996-01-01

    Atomicity in Electronic Commerce J. D. Tygar January 1996 CMU-CS-96-112 School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213...other research sponsor. Keywords: electronic commerce , atomicity, NetBill, IBIP, cryptography, transaction pro- cessing, ACID, franking, electronic ...goods over networks. Electronic commerce has inspired a large variety of work. Unfortunately, much of that work ignores traditional transaction

  14. Optimization of Neutral Atom Imagers

    Science.gov (United States)

    Shappirio, M.; Coplan, M.; Balsamo, E.; Chornay, D.; Collier, M.; Hughes, P.; Keller, J.; Ogilvie, K.; Williams, E.

    2008-01-01

    The interactions between plasma structures and neutral atom populations in interplanetary space can be effectively studied with energetic neutral atom imagers. For neutral atoms with energies less than 1 keV, the most efficient detection method that preserves direction and energy information is conversion to negative ions on surfaces. We have examined a variety of surface materials and conversion geometries in order to identify the factors that determine conversion efficiency. For chemically and physically stable surfaces smoothness is of primary importance while properties such as work function have no obvious correlation to conversion efficiency. For the noble metals, tungsten, silicon, and graphite with comparable smoothness, conversion efficiency varies by a factor of two to three. We have also examined the way in which surface conversion efficiency varies with the angle of incidence of the neutral atom and have found that the highest efficiencies are obtained at angles of incidence greater then 80deg. The conversion efficiency of silicon, tungsten and graphite were examined most closely and the energy dependent variation of conversion efficiency measured over a range of incident angles. We have also developed methods for micromachining silicon in order to reduce the volume to surface area over that of a single flat surface and have been able to reduce volume to surface area ratios by up to a factor of 60. With smooth micro-machined surfaces of the optimum geometry, conversion efficiencies can be increased by an order of magnitude over instruments like LENA on the IMAGE spacecraft without increase the instruments mass or volume.

  15. Influence of multi-element ion beam bombardment on the corrosion behavior of iron and steel

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Tian; Run, Wu; Weiping, Cai; Rutao, Wang (Wuhan Iron and Steel Univ., HB (China)); Godechot, X.; Brown, I. (Lawrence Berkeley Lab., CA (United States))

    1991-06-01

    The effect of multi-element ion implantation on the corrosion resistance to acid solution has been studied for stainless steel, medium carbon steel, pure iron, and chromium-deposited iron. The implanted elements were Cu, Mo, Cr, Ni, Yb and Ti at doses of each species of from 5 {times} 10{sup 15} to 1 {times} 10{sup 17} cm{sup {minus}2} and at ion energies of up to 100 keV. The stainless steel used was 18-8 Cr-Ni, and the medium carbon steel was 0.45% C. The implanted samples were soaked in dilute sulfuric acid solution for periods up to 48 hours and the weight loss measured by atomic absorption spectroscopy. The kinetic parameter values describing the weight loss as a function of time were determined for all samples. In this paper we summarize the corrosion resistance behavior for the various different combinations of implanted species, doses, and substrates. The influence of the composition and structure of the modified surface layer is discussed.8 refs., 5 figs., 2 tabs.

  16. Theoretical atomic physics

    CERN Document Server

    Friedrich, Harald

    2017-01-01

    This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...

  17. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  18. Maximally Atomic Languages

    Directory of Open Access Journals (Sweden)

    Janusz Brzozowski

    2014-05-01

    Full Text Available The atoms of a regular language are non-empty intersections of complemented and uncomplemented quotients of the language. Tight upper bounds on the number of atoms of a language and on the quotient complexities of atoms are known. We introduce a new class of regular languages, called the maximally atomic languages, consisting of all languages meeting these bounds. We prove the following result: If L is a regular language of quotient complexity n and G is the subgroup of permutations in the transition semigroup T of the minimal DFA of L, then L is maximally atomic if and only if G is transitive on k-subsets of 1,...,n for 0 <= k <= n and T contains a transformation of rank n-1.

  19. Atomic Number Dependence of Hadron Production at Large Transverse Momentum in 300 GeV Proton--Nucleus Collisions

    Science.gov (United States)

    Cronin, J. W.; Frisch, H. J.; Shochet, M. J.; Boymond, J. P.; Mermod, R.; Piroue, P. A.; Sumner, R. L.

    1974-07-15

    In an experiment at the Fermi National Accelerator Laboratory we have compared the production of large transverse momentum hadrons from targets of W, Ti, and Be bombarded by 300 GeV protons. The hadron yields were measured at 90 degrees in the proton-nucleon c.m. system with a magnetic spectrometer equipped with 2 Cerenkov counters and a hadron calorimeter. The production cross-sections have a dependence on the atomic number A that grows with P{sub 1}, eventually leveling off proportional to A{sup 1.1}.

  20. Diamond-like atomic-scale composite films: Surface properties and stability studied by STM and AFM

    Energy Technology Data Exchange (ETDEWEB)

    Dorfman, B.; Abraizov, M. [SUNY, Farmingdale, NY (United States); Pollak, F.H. [CUNY, Brooklyn, NY (United States); Eby, R. [TopoMetrix, Bedminster, NJ (United States); Rong, Z.Y. [SUNY, Stony Brook, NY (United States); Strongin, M.; Yang, X.Q. [Brookhaven National Lab., Upton, NY (United States)

    1995-10-01

    Amorphous ``diamond-like/quartz-like`` composites a-(C:H/Si:O) and metal containing a-(C:H/Si:O/Me) constitute a novel class of diamond-related materials with a number of unique bulk and surface properties. In order to gain a more fundamental understanding of the surface properties and stability of these solids we have performed a scanning tunneling and atomic force microscopy investigation of both a-(C:H/Si:O) and a-(C:H/Si:O/Me) films, including the effects of ion bombardment and annealing.

  1. Project Physics Tests 5, Models of the Atom.

    Science.gov (United States)

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 5 are presented in this booklet. Included are 70 multiple-choice and 23 problem-and-essay questions. Concepts of atomic model are examined on aspects of relativistic corrections, electron emission, photoelectric effects, Compton effect, quantum theories, electrolysis experiments, atomic number and mass,…

  2. Ab initio calculations and modelling of atomic cluster structure

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Lyalin, Andrey G.; Solov'yov, Andrey V.

    2004-01-01

    framework for modelling the fusion process of noble gas clusters is presented. We report the striking correspondence of the peaks in the experimentally measured abundance mass spectra with the peaks in the size-dependence of the second derivative of the binding energy per atom calculated for the chain...... of the noble gas clusters up to 150 atoms....

  3. Initial mass function of intermediate-mass black hole seeds

    NARCIS (Netherlands)

    Ferrara, A.; Salvadori, S.; Yue, B.; Schleicher, D.

    We study the initial mass function (IMF) and hosting halo properties of intermediate-mass black holes (IMBHs, 104-6 M⊙) formed inside metal-free, UV-illuminated atomic-cooling haloes (virial temperature Tvir ≥ 104 K) either via the direct collapse of the gas or via an intermediate supermassive star

  4. Atom Probe Tomography of Geomaterials

    Science.gov (United States)

    Parman, S. W.; Diercks, D.; Gorman, B.; Cooper, R. F.

    2013-12-01

    From the electron microprobe to the secondary ion microprobe to laser-ablation ICP-MS, steady improvements in the spatial resolution and detection limits of geochemical micro-analysis have been central to generating new discoveries. Atom probe tomography (APT) is a relatively new technology that promises nm-scale spatial resolution (in three dimensions) with ppm level detection limits. The method is substantially different from traditional beam-based (electron, ion, laser) methods. In APT, the sample is shaped (usually with a dual-beam FIB) into a needle with typical dimensions of 1-2 μm height and 100-200 nm diameter. Within the atom probe, the needle is evaporated one atom (ideally) at a time by a high electric field (ten's of V per square nm at the needle tip). A femtosecond laser (12 ps pulse width) is used to assist in evaporating non-conducting samples. The two-dimensional detector locates where the atom was released from the needle's surface and so can reconstruct the positions of all detected atoms in three dimensions. It also records the time of flight of the ion, which is used to calculate the mass/charge ratio of the ion. We will discuss our results analyzing a range of geologic materials. In one case, naturally occurring platinum group alloys (PGA) from the Josephine Ophiolite have been imaged. Such alloys are of interest as recorders of the Os heterogeneity of the mantle [1,2]. Optimal ablation was achieved with a laser power of 120-240 pJ and laser pulse rates 500 kHz. Runs were stopped after 10 million atoms were imaged. An example analysis is: Pt 61(1), Fe 26.1(9), Rh 1.20(4), Ir 7.0(7), Ni 2.65(8), Ru 0.20(9), Cu 1.22(8), Co 0.00029(5). Values are in atomic %; values in parentheses are one-sigma standard deviations on five separate needles from the same FIB lift-out, which was 30 μm long. Assuming the sample is homogenous over the 30 μm from which the needle was extracted, the analyses suggest relative errors for major elements below 5% and for

  5. Influence of substrate pre-treatments by Xe{sup +} ion bombardment and plasma nitriding on the behavior of TiN coatings deposited by plasma reactive sputtering on 100Cr6 steel

    Energy Technology Data Exchange (ETDEWEB)

    Vales, S., E-mail: sandra.vales@usp.br [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Brito, P., E-mail: ppbrito@gmail.com [Pontifícia Universidade Católica de Minas Gerais (PUC-MG), Av. Dom José Gaspar 500, 30535-901 Belo Horizonte, MG (Brazil); Pineda, F.A.G., E-mail: pipe8219@gmail.com [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Ochoa, E.A., E-mail: abigail_ochoa@hotmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Droppa, R., E-mail: roosevelt.droppa@ufabc.edu.br [Universidade Federal do ABC (UFABC), Av. dos Estados, 5001, Santo André, SP CEP 09210-580 (Brazil); Garcia, J., E-mail: jose.garcia@sandvik.com [Sandvik Coromant R& D, Lerkrogsvägen 19, SE-12680, Stockholm (Sweden); Morales, M., E-mail: monieriz@gmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Alvarez, F., E-mail: alvarez@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); and others

    2016-07-01

    In this paper the influence of pre-treating a 100Cr6 steel surface by Xe{sup +} ion bombardment and plasma nitriding at low temperature (380 °C) on the roughness, wear resistance and residual stresses of thin TiN coatings deposited by reactive IBAD was investigated. The Xe{sup +} ion bombardment was carried out using a 1.0 keV kinetic energy by a broad ion beam assistance deposition (IBAD, Kaufman cell). The results showed that in the studied experimental conditions the ion bombardment intensifies nitrogen diffusion by creating lattice imperfections, stress, and increasing roughness. In case of the combined pre-treatment with Xe{sup +} ion bombardment and subsequent plasma nitriding, the samples evolved relatively high average roughness and the wear volume increased in comparison to the substrates exposed to only nitriding or ion bombardment. - Highlights: • Effect of Xe ion bombardment and plasma nitriding on TiN coatings was investigated. • Xe ion bombardment with 1.0 KeV increases nitrogen retention in plasma nitriding. • 1.0 KeV ion impact energy causes sputtering, thus increasing surface roughness. • TiN coating wear is minimum after plasma nitriding due to lowest roughness.

  6. An Atomic Gravitational Wave Interferometric Sensor (AGIS)

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Savas; /Stanford U., Phys. Dept.; Graham, Peter W.; /SLAC; Hogan, Jason M.; Kasevich, Mark A.; /Stanford U., Phys. Dept.; Rajendran, Surjeet; /SLAC /Stanford U., Phys. Dept.

    2008-08-01

    We propose two distinct atom interferometer gravitational wave detectors, one terrestrial and another satellite-based, utilizing the core technology of the Stanford 10m atom interferometer presently under construction. Each configuration compares two widely separated atom interferometers run using common lasers. The signal scales with the distance between the interferometers, which can be large since only the light travels over this distance, not the atoms. The terrestrial experiment with baseline {approx} 1 km can operate with strain sensitivity {approx} 10{sup -19}/{radical}Hz in the 1 Hz-10 Hz band, inaccessible to LIGO, and can detect gravitational waves from solar mass binaries out to megaparsec distances. The satellite experiment with baseline {approx} 1000 km can probe the same frequency spectrum as LISA with comparable strain sensitivity {approx} 10{sup -20}/{radical}Hz. The use of ballistic atoms (instead of mirrors) as inertial test masses improves systematics coming from vibrations, acceleration noise, and significantly reduces spacecraft control requirements. We analyze the backgrounds in this configuration and discuss methods for controlling them to the required levels.

  7. Separation of seven arsenic compounds by high performance liquid chromatography with on-line detection by hydrogen-argon flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, S. H.; Larsen, Erik Huusfeldt; Pritzl, G.

    1992-01-01

    the HPLC column to the nebulizer of the atomic absorption spectrometer. Arsenite, arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) were separated from each other and from the co-injected cationic arsenic compounds, arsenobetaine (AsB), arsenocholine (AsC) and the tetramethylarsonium ion (TMAs...... of mixtures of arsenic standards into the HPLC system were: arsenite, As(III) 1.1; arsenate, As(V) 1.4; MMA 1.4; DMA 0.7; AsB 0.3; AsC 0.5; and the TMAs 0.4. The HPLC-AAS system was used for the analysis of arsenic species in aqueous extracts of soil samples from a polluted land site. Only arsenate was found...

  8. Separation of seven arsenic compounds by high-performance liquid chromatography with on-line detection by hydrogen–argon flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, S. H.; Larsen, E. H.; Pritzl, G.

    1992-01-01

    the HPLC column to the nebulizer of the atomic absorption spectrometer. Arsenite, arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) were separated from each other and from the co-injected cationic arsenic compounds, arsenobetaine (AsB), arsenocholine (AsC) and the tetramethylarsonium ion (TMAs...... of mixtures of arsenic standards into the HPLC system were: arsenite, As(III) 1.1; arsenate, As(V) 1.4; MMA 1.4; DMA 0.7; AsB 0.3; AsC 0.5; and the TMAs 0.4. The HPLC-AAS system was used for the analysis of arsenic species in aqueous extracts of soil samples from a polluted land site. Only arsenate was found...

  9. On the history of the early meteoritic bombardment of the Moon: Was there a terminal lunar cataclysm?

    Science.gov (United States)

    Michael, Greg; Basilevsky, Alexander; Neukum, Gerhard

    2018-03-01

    This work revisits the hypothesis of the so-called 'lunar terminal cataclysm' suggested by Tera et al. (1973, 1974) as a strong peak in the meteorite bombardment of the Moon around 3.9 Ga ago. According to the hypothesis, most of the impact craters observed on the lunar highlands formed during this short time period and thus formed the majority of the lunar highland impact breccias and melts. The hypothesis arose from the observation that the ages of highland samples from all the lunar missions are mostly grouped around 3.9-4.0 Ga. Since those missions, however, radiometric dating techniques have progressed and many samples, both old and new, have been re-analyzed. Nevertheless, the debate over whether there was a terminal cataclysm persists. To progress in this problem we summarized results of 269 K-Ar datings (mostly made using the 40Ar-39Ar technique) of highland rocks represented by the Apollo 14, 15, 16, 17 and Luna 20 samples and 94 datings of clasts of the highland rocks from 23 lunar meteorites representing 21 localities on the lunar surface, and considered them jointly with the results of our modelling of the cumulative effect of the impact gardening process on the presence of impact melt of different ages at the near-surface of the Moon. The considered results of K-Ar dating of the Apollo-Luna samples of lunar highland rocks confirmed a presence of strong peak centered at 3.87 Ga. But since the time when the hypothesis of terminal cataclysm was suggested, it has become clear that this peak could be a result of sampling bias: it is the only prominent feature at the sites with an apparent domination of Imbrium basin ejecta (Apollo 14 and 15) and the age pattern is more complicated for the sites influenced not only by Imbrium ejecta but also that of other basins (Nectaris at the Apollo 16 site and Serenitatis at the Apollo 17 site). Our modelling shows that the cataclysm, if it occurred, should produce a strong peak in the measured age values but we see in

  10. RISK: A Resonance Ionization Mass Spectrometer for Krypton

    Science.gov (United States)

    Strashnov, I.; Blagburn, D. J.; Gilmour, J. D.

    2010-03-01

    A resonance ionization mass spectrometer for krypton (RISK) has been developed. Atoms are released by a step-heating and ionized by pulsed tunable lasers. The sensitivity below 1000 atoms is demonstrated by detecting 81Kr in noncumulate eucrite Stannern.

  11. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  12. Physics of the atom

    CERN Document Server

    Wehr, Russell M; Adair, Thomas W

    1984-01-01

    The fourth edition of Physics of the Atom is designed to meet the modern need for a better understanding of the atomic age. It is an introduction suitable for students with a background in university physics and mathematical competence at the level of calculus. This book is designed to be an extension of the introductory university physics course into the realm of atomic physics. It should give students a proficiency in this field comparable to their proficiency in mechanics, heat, sound, light, and electricity.

  13. Nanoscale topographic pattern formation on Kr{sup +}-bombarded germanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Perkinson, Joy C.; Madi, Charbel S.; Aziz, Michael J. [Harvard School of Engineering and Applied Sciences, 9 Oxford Street, Cambridge, Massachusetts 02138 (United States)

    2013-03-15

    The nanoscale pattern formation of Ge surfaces uniformly irradiated by Kr{sup +} ions was studied in a low-contamination environment at ion energies of 250 and 500 eV and at angles of 0 Degree-Sign through 80 Degree-Sign . The authors present a phase diagram of domains of pattern formation occurring as these two control parameters are varied. The results are insensitive to ion energy over the range covered by the experiments. Flat surfaces are stable from normal incidence up to an incidence angle of {theta} = 55 Degree-Sign from normal. At higher angles, the surface is linearly unstable to the formation of parallel-mode ripples, in which the wave vector is parallel to the projection of the ion beam on the surface. For {theta} {>=} 75 Degree-Sign the authors observe perpendicular-mode ripples, in which the wave vector is perpendicular to the ion beam. This behavior is qualitatively similar to those of Madi et al. for Ar{sup +}-irradiated Si but is inconsistent with those of Ziberi et al. for Kr{sup +}-irradiated Ge. The existence of a window of stability is qualitatively inconsistent with a theory based on sputter erosion [R. M. Bradley and J. M. Harper, J. Vac. Sci. Technol. A 6, 2390 (1988)] and qualitatively consistent with a model of ion impact-induced mass redistribution [G. Carter and V. Vishnyakov, Phys. Rev. B 54, 17647 (1996)] as well as a crater function theory incorporating both effects [S. A. Norris et al., Nat. Commun. 2, 276 (2011)]. The critical transition angle between stable and rippled surfaces occurs 10 Degree-Sign -15 Degree-Sign above the value of 45 Degree-Sign predicted by the mass redistribution model.

  14. Radioactive Elements in the Standard Atomic Weights Table.

    Energy Technology Data Exchange (ETDEWEB)

    Holden,N.E.

    2007-08-04

    In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (or longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular element has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number is inconsistent with the primary purpose of the Table, i.e., to provide accurate values of 'these constants' for use in various chemical calculations. In addition to the Table of Atomic Weights, the Commission included an auxiliary Table of Radioactive Elements for the first time, where the entry would be the isotope of that element which was the most stable, i.e., the one with the longest known half-life. In their 1973 Report, the Commission noted that the users of the main Table of Atomic Weights were dissatisfied with the omission of values for some elements in that Table and it was decided to reintroduce the mass number for the radioactive elements into the main Table. In their 1983 Report, the Commission decided that radioactive elements were considered to lack a characteristic terrestrial

  15. Atomic & Molecular Interactions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-07-12

    The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  16. The Casimir atomic pendulum

    Energy Technology Data Exchange (ETDEWEB)

    Razmi, H. [Department of Physics, University of Qom, Qom 37185-359 (Iran, Islamic Republic of)], E-mail: razmi@qom.ac.ir; Abdollahi, M. [Department of Physics, University of Qom, Qom 37185-359 (Iran, Islamic Republic of)], E-mail: mah.abdollahi@gmail.com

    2008-11-10

    We want to introduce an atomic pendulum whose driving force (torque) is due to the quantum vacuum fluctuations. Applying the well-known Casimir-Polder effect to a special configuration (a combined structure of an atomic nanostring and a conducting plate), an atomic pendulum (Casimir atomic pendulum) is designed. Using practically acceptable data corresponding to the already known world of nanotechnology and based on reasonable/reliable numerical estimates, the period of oscillation for the pendulum is computed. This pendulum can be considered as both a new micro(nano)-electromechanical system and a new simple vacuum machine. Its design may be considered as a first step towards realizing the visualized vacuum (Casimir) clock{exclamation_point}.

  17. The Casimir atomic pendulum

    Science.gov (United States)

    Razmi, H.; Abdollahi, M.

    2008-11-01

    We want to introduce an atomic pendulum whose driving force (torque) is due to the quantum vacuum fluctuations. Applying the well-known Casimir-Polder effect to a special configuration (a combined structure of an atomic nanostring and a conducting plate), an atomic pendulum (Casimir atomic pendulum) is designed. Using practically acceptable data corresponding to the already known world of nanotechnology and based on reasonable/reliable numerical estimates, the period of oscillation for the pendulum is computed. This pendulum can be considered as both a new micro(nano)-electromechanical system and a new simple vacuum machine. Its design may be considered as a first step towards realizing the visualized vacuum (Casimir) clock!

  18. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  19. Dalton's Atomic Theory

    National Research Council Canada - National Science Library

    DOBBIN, LEONARD

    1896-01-01

    WITH reference to the communications from the authors and from the reviewer of the "New View of the Origin of Dalton's Atomic Theory," published in NATURE for May 14, I beg leave to offer the following remarks...

  20. Atomic Interferometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  1. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  2. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)

  3. Life atomic a history of radioisotopes in science and medicine

    CERN Document Server

    Creager, Angela N H

    2013-01-01

    After World War II, the US Atomic Energy Commission (AEC) began mass-producing radioisotopes, sending out nearly 64,000 shipments of radioactive materials to scientists and physicians by 1955. Even as the atomic bomb became the focus of Cold War anxiety, radioisotopes represented the government's efforts to harness the power of the atom for peace-advancing medicine, domestic energy, and foreign relations.             In Life Atomic, Angela N. H. Creager tells the story of how these radioisotopes, which were simultaneously scientific tools and political icons, transformed biomedicine and ecolog

  4. Atomic Clocks Research - An Overview.

    Science.gov (United States)

    1987-08-15

    magnet. Since atomic deflection in an inhomogeneous magnetic field is inversely proportional to the square of the atomic speed, the atomic velocity...purifier and controlled leak; an atomic source (i.e., the dissociator under 39 study); a dipole electromagnetic with pole pieces shaped to produce an...34Relaxation Magnetique d’Atomes de Rubidium sur des Parois Paraffines," J. Phys. (Paris) 24, 379 (1963). 21. S. Wexler, "Deposition of Atomic Beams

  5. Wave Atom Based Watermarking

    OpenAIRE

    Bukhari, Ijaz; Nuhman-ul-Haq; Hyat, Khizar

    2013-01-01

    Watermarking helps in ensuring originality, ownership and copyrights of a digital image. This paper aims at embedding a Watermark in an image using Wave Atom Transform. Preference of Wave Atoms on other transformations has been due to its sparser expansion, adaptability to the direction of local pattern, and sharp frequency localization. In this scheme, we had tried to spread the watermark in an image so that the information at one place is very small and undetectable. In order to extract the...

  6. Hirshfeld atom refinement.

    Science.gov (United States)

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  7. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  8. Atomic Bomb Health Benefits

    OpenAIRE

    Luckey, T. D.

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation,...

  9. Study on Temporal and Spatial Distributions of Ba Atoms in Fluorescent Lamp Discharge Using Laser-Induced Florescence

    Science.gov (United States)

    AlyHendy, Ahmed Samir; Yamashita, Go; Yamagata, Yukihiko; Uchino, Kiichiro; Ueda, Takashi; Manabe, Yoshio

    2006-10-01

    A laser-induced fluorescence (LIF) technique was applied to the measurements of the temporal and spatial distributions of Ba atoms in the vicinity of the electrode of a fluorescent lamp operated at 60 Hz. Ground-state (61S0) Ba atoms were excited to a 51P1 level (350.1 nm) by a frequency-doubled dye laser beam, and the subsequent fluorescence (51P1-51D2, 582.6 nm) was detected. Over a whole periodic time (16.67 ms), the density of the Ba atoms was found to have two peaks, and the number of Ba atoms emitted in the anode half-cycle was about twofold larger than that emitted in the cathode half-cycle. This difference between the Ba atoms emitted during the anode half-cycle and those emitted during the cathode half-cycle was studied for lamps with different gas pressures. Ba atoms were found to be emitted mainly from the hot spot of the filament electrode. It is suggested that the main factor for Ba atom emission from the electrode is not sputtering by ion bombardment but thermal evaporation.

  10. Atomic bomb and leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Ichimaru, M.; Tomonaga, M.; Amenomori, T.; Matsuo, T. (Nagasaki Univ. (Japan). School of Medicine)

    1991-12-01

    Characteristic features of the leukemia among atomic bomb survivors were studied. Dose estimates of atomic bomb radiation were based on T65D, but the new dosimetry system DS86 was used for some analyses. The ratio of a single leukemia type to all leukemias was highest for chronic myelogenous leukemia (CML) in Hiroshima, and the occurrence of CML was thought to be most characteristic to atomic bomb radiation induced leukemia. The threshold of CML occurrence in Hiroshima is likely to be between 0.5{approx}0.09 Gy. However, the threshold of acute leukemia appears to be nearly 1 Gy. In the distribution of acute myeloid leukemia (AML) subtypes by French-American-British classification, there was no M3 case in 1 Gy or more group, although several atypical AML cases of survivors were observed. Although aplastic anemia has not increased as a late effect of the atomic bomb radiation exposure, many atypical leukemia or other myeloproliferative diseases who had been diagnosed as aplastic anemia or its related diseases have been experienced among atomic bomb survivors. Chromosome study was conducted using colony forming cells induced by hemopoietic stem cells of peripheral blood of proximal survivors. Same chromosome aberrations were observed in colony forming cells and peripheral T-cells in several atomic bomb survivors. (author).

  11. THE ATOMIC WEIGHTS COMMISSION AND ISOTOPIC ABUNDANCE RATIO DETERMINATIONS.

    Energy Technology Data Exchange (ETDEWEB)

    HOLDEN, N.E.

    2005-08-07

    Following Thomson's discovery of stable isotopes in non-radioactive chemical elements, the derivation of atomic weight values from mass spectrometric measurements of isotopic abundance ratios moved very slowly. Forty years later, only 3 1/2 % of the recommended values were based on mass spectrometric measurements and only 38% in the first half century. It might be noted that two chemical elements (tellurium and mercury) are still based on chemical measurements, where the atomic weight value calculated from the relative isotopic abundance measurement either agrees with the value from the chemical measurement or the atomic weight value calculated from the relative isotopic abundance measurement falls within the uncertainty of the chemical measurement of the atomic weight. Of the 19 chemical elements, whose atomic weight is based on non-corrected relative isotopic abundance measurements, five of these are two isotope systems (indium, iridium, lanthanum, lutetium and tantalum) and one is a three-isotope system (oxygen).

  12. In-situ study of emerging metallicity and memory effect on ion-beam bombarded strontium titanate surface

    Science.gov (United States)

    Gross, Heiko

    In this work we present an investigation of the occurrence of conductivity on the surface of SrTiO3 due to argon ion bombardment. We created a model to describe this process and found that the temperature during the ion milling is a crucial factor for the conductivity. Depending on the temperatures we found surface carrier densities ranging from nS = 1:5 x 1018 to 2:6 x 1020 cm -3 by just analyzing the conductivity behavior. Clustering of vacancies goes along with temperature and affects the conductivity significantly. Furthermore we found that ion milling is a gentle way to create vacancies because the clustering rate is small compared to annealing samples in high vacuum. The amount of clusters at room temperature was measured to be around 3-4 times higher than at -140°C. We found that samples with a conducting surface change their resistance over time at room-temperature due to the ongoing process of oxygen vacancy clustering. This effect may be suppressed by decreasing the temperature. The bistable switching behavior in oxygen deficient SrTiO3 is shown without any additional doping. The vacancy migration is the major mechanism behind this memory effect. Comparing this behavior with annealed samples in high vacuum shows that the therein present amount of vacancy clusters must be much larger and has a negative effect on the bistable switching behavior.

  13. Computer simulations of material ejection during C60 and Arm bombardment of octane and β-carotene

    Science.gov (United States)

    Palka, G.; Kanski, M.; Maciazek, D.; Garrison, B. J.; Postawa, Z.

    2015-06-01

    Molecular dynamics (MD) computer simulations are used to investigate material ejection and fragment formation during keV C60 and Arm (m = 60, 101, 205, 366, 872 and 2953) bombardment of organic solids composed from octane and β-carotene molecules at 0° and 45° impact angle. Both systems are found to sputter efficiently. For the octane system, material removal occurs predominantly by ejection of intact molecules, while fragment emission is a significant ejection channel for β-carotene. A difference in the molecular dimensions is proposed to explain this observation. It has been shown that the dependence of the sputtering yield Y on the primary kinetic energy E and the cluster size n can be expressed in a simplified form if represented in reduced units. A linear and nonlinear dependence of the Y/n on the E/n are identified and the position of the transition point from the linear to nonlinear regions depends on the size of the cluster projectile. The impact angle has a minor influence on the shape of the simplified representation.

  14. Effect of ion bombardment and substrate orientation on structure and properties of titanium nitride films deposited by unbalanced magnetron sputtering

    CERN Document Server

    Guruvenket, S

    2002-01-01

    The effect of substrate orientation and ion bombardment during the growth on the structure and properties of TiN films deposited by reactive unbalanced magnetron sputtering has been reported. Films deposited at a nitrogen partial pressure of 5x10 sup - sup 5 mbar and a current density of 2.50 mA cm-2 were golden yellow in color, characteristic of stoichiometric TiN. The effect of Si(100) and Si(111) substrates on the TiN film along with the substrate bias has been investigated. With an increase in the substrate bias on Si(111) substrate, TiN(111) is the most preferred orientation. On a Si(100) substrate with an increase in the substrate bias, TiN(220) orientation has been observed. The influence of the substrate on the growth of TiN films has been explained in terms of surface energy. The variation of grain size, resistivity, and the internal stress of TiN films as the function of substrate bias have also been investigated.

  15. Intensity distributions of reflected surface channeling protons scattered on surfaces of electron-bombarded alkali halide crystals

    Science.gov (United States)

    Fukazawa, Y.; Kihara, K.; Iwamoto, K.; Susuki, Y.

    2013-11-01

    We have examined the surface-channeling of 550 keV protons on electron-bombarded KBr(0 0 1) surfaces at grazing incidence. On the surface, electron-stimulated desorption (ESD) resulting from the irradiation of 5 keV electrons changes the surface morphology. In order to investigate the change of the surface morphology, the luminous intensity distributions observed on a fluorescent screen (scattering patterns) of the reflected protons under the surface-channeling conditions are measured. Normalized specular intensity of the protons oscillates, and the results of computer simulations show that the period of the intensity oscillation agrees with the period of layer-by-layer desorption. The measured period of the oscillation is comparable to the simulated one, i.e., the period of the desorption, however, the measured amplitude of the oscillation is weak. This shows that the layer-by-layer desorption of the experimental surface is observed but is not as remarkable as that of the perfect surface introduced in the simulation.

  16. Intensity distributions of reflected surface channeling protons scattered on surfaces of electron-bombarded alkali halide crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fukazawa, Y., E-mail: yukofu@cc.osaka-kyoiku.ac.jp; Kihara, K.; Iwamoto, K.; Susuki, Y.

    2013-11-15

    We have examined the surface-channeling of 550 keV protons on electron-bombarded KBr(0 0 1) surfaces at grazing incidence. On the surface, electron-stimulated desorption (ESD) resulting from the irradiation of 5 keV electrons changes the surface morphology. In order to investigate the change of the surface morphology, the luminous intensity distributions observed on a fluorescent screen (scattering patterns) of the reflected protons under the surface-channeling conditions are measured. Normalized specular intensity of the protons oscillates, and the results of computer simulations show that the period of the intensity oscillation agrees with the period of layer-by-layer desorption. The measured period of the oscillation is comparable to the simulated one, i.e., the period of the desorption, however, the measured amplitude of the oscillation is weak. This shows that the layer-by-layer desorption of the experimental surface is observed but is not as remarkable as that of the perfect surface introduced in the simulation.

  17. Convenient recycling and reuse of bombarded [¹⁸O]H₂O for the production and the application of [¹⁸F]F⁻.

    Science.gov (United States)

    Rötering, Sven; Franke, Karsten; Zessin, Jörg; Brust, Peter; Füchtner, Frank; Fischer, Steffen; Steinbach, Jörg

    2015-07-01

    The limited availability and the increasing demands of [(18)O]H2O force the reuse of bombarded [(18)O]H2O for the production of [(18)F]F(-) at least for the purposes of research. Therefore, inorganic and organic contaminants have to be removed from the [(18)O]H2O after bombardment. We present a simple, effective, easy-handling and reliable method of [(18)O]H2O purification including oxidation and distillation. The obtained recycled [(18)O]H2O had comparable quality to commercially distributed [(18)O]water. This was confirmed by a detailed comparison of produced radionuclides and their activities and the application of [(18)F]F(-) for the automated synthesis of [(18)F]fluspidine. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Do atoms and anti-atoms obey the same laws of physics?

    CERN Multimedia

    Jeffrey Hangst

    2010-01-01

    ALPHA physicists have recently succeeded in trapping anti-atoms for the first time. Being able to hold on to the simplest atoms of antimatter is an important step towards the collaboration’s ultimate goal: precision spectroscopic comparison of hydrogen and antihydrogen. The question they are seeking to answer: do atoms and anti-atoms obey the same laws of physics? The Standard Model says that they must.   The ALPHA Collaboration celebrates the successful results. The ALPHA collaboration has taken it up a gear and trapped 38 atoms of antihydrogen for the first time. Antihydrogen atoms have been mass-produced at the Antiproton Decelerator (AD) since 2002, when ATHENA (ALPHA’s predecessor) and ATRAP learned how to mix clouds of antiprotons and positrons at cryogenic temperatures. However, these anti-atoms were not confined, and flew off in a few microseconds to meet their fate: annihilation with matter in the walls of the experiment. ALPHA uses antiprotons produced at...

  19. The unexpected formation of Au δ+ -Si δ- by the resonance neutralization of Ar + during the low energy bombardment of Au nanoparticles on c-Si

    Science.gov (United States)

    Yang, De-Quan; Sacher, Edward

    2009-05-01

    Nanoscale Au layers, with irregular porosities, have been formed by the low energy Ar + bombardment of Au nanoparticles that were sputter-deposited onto native oxide-covered Si surfaces. High-resolution field emission scanning electron microcopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the formation and evolution of the nanoporous layer. Under Ar + bombardment, the Au nanoparticles that were initially deposited were observed to flatten and spread across the native oxide surface, without diffusing, finally coalescing at their edges to form a nanoporous film having irregular pore dimensions. XPS showed that this evolution was accompanied by the loss of Au as a result of sputtering. The formation of such porous films necessitates strong interfacial bonding to avoid the lateral diffusion of the Au nanoparticles, and their ultimate coalescence into larger nanoparticles. We demonstrated that Ar + beam bombardment invariably caused the formation of Au δ+ -Si δ- bonding, rather than the expected Au δ- -Si δ+ bonding, and we explain this to be due to the resonance neutralization of the Ar + beam on impacting the Au layer. We also reveal that the presumed formation of AuSi x is not quantifiable by XPS, due to the superposition of the chemical shift of the Au nanoparticles with that of the quantum size effect, during Au loss on sputtering.

  20. Nanometer-scale isotope analysis of bulk diamond by atom probe tomography

    NARCIS (Netherlands)

    Schirhagl, R.; Raatz, N.; Meijer, J.; Markham, M.; Gerstl, S. S. A.; Degen, C. L.

    2015-01-01

    Atom-probe tomography (APT) combines field emission of atoms with mass spectrometry to reconstruct three-dimensional tomograms of materials with atomic resolution and isotope specificity. Despite significant recent progress in APT technology, application to wide-bandgap materials with strong