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Sample records for energy electron-neutrino scattering

  1. Electron Neutrino Charged-Current Quasielastic Scattering in the MINERvA Experiment

    SciTech Connect

    Wolcott, J.

    2015-12-31

    The electron-neutrino charged-current quasielastic (CCQE) cross section on nuclei is an important input parameter for electron neutrino appearance oscillation experiments. Current experiments typically begin with the muon neutrino cross section and apply theoretical corrections to obtain a prediction for the electron neutrino cross section. However, at present no experimental verification of the estimates for this channel at an energy scale appropriate to such experiments exists. We present the cross sections for a CCQE-like process determined using the MINERvA detector, which are the first measurements of any exclusive reaction in few-GeV electron neutrino interactions. The result is given as differential cross-sections vs. the electron energy, electron angle, and square of the four-momentum transferred to the nucleus, $Q^{2}$. We also compute the ratio to a muon neutrino cross-section in $Q^{2}$ from MINERvA. We find satisfactory agreement between these measurements and the predictions of the GENIE generator. We furthermore report on a photon-like background unpredicted by the generator which we interpret as neutral-coherent diffractive scattering from hydrogen.

  2. Measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon at $$\\langle E_{\

    DOE PAGESBeta

    Wolcott, J.

    2016-02-25

    The first direct measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in the electron production angle, electron energy, and Q2 are presented. The ratio of the quasielastic, flux-integrated differential cross section in Q2 for νe with that of similarly selected νμ-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current νe interactions used by long-baseline neutrino oscillation experiments. Furthermore, the data are found tomore » be consistent with lepton universality and are well described by the predictions of the neutrino event generator GENIE.« less

  3. Electron-neutrino scattering off nuclei from two different theoretical perspectives

    NASA Astrophysics Data System (ADS)

    Martini, M.; Jachowicz, N.; Ericson, M.; Pandey, V.; Van Cuyck, T.; Van Dessel, N.

    2016-07-01

    We analyze charged-current electron-neutrino cross sections on carbon. We consider two different theoretical approaches, on one hand the continuum random phase approximation (CRPA) which allows a description of giant resonances and quasielastic excitations, on the other hand the RPA-based calculations which are able to describe multinucleon emission and coherent and incoherent pion production as well as quasielastic excitations. We compare the two approaches in the genuine quasielastic channel, and find a satisfactory agreement between them at large energies while at low energies the collective giant resonances show up only in the CRPA approach. We also compare electron-neutrino cross sections with the corresponding muon-neutrino ones in order to investigate the impact of the different charged-lepton masses. Finally, restricting to the RPA-based approach, we compare the sum of quasielastic, multinucleon emission, coherent, and incoherent one-pion production cross sections (folded with the electron-neutrino T2K flux) with the charged-current inclusive electron-neutrino differential cross sections on carbon measured by T2K. We find a good agreement with the data. The multinucleon component is needed in order to reproduce the T2K electron-neutrino inclusive cross sections.

  4. Electron Neutrino Charged-Current Quasielastic Scattering in the MINERvA Experiment

    SciTech Connect

    Wolcott, Jeremy

    2015-10-28

    The electron-neutrino charged-current quasielastic (CCQE) cross section on nuclei is an important input parameter to appearance-type neutrino oscillation experiments. Current experiments typically work from the muon neutrino cross section and apply corrections from theoretical arguments to obtain a prediction for the electron neutrino cross section, but to date there has been no experimental verification of the estimates for this channel at an energy scale appropriate to such experiments. We present the first measurement of an exclusive reaction in few-GeV electron neutrino interactions, namely, the cross section for a CCQE-like process, made using the MINERvA detector. The result is given as differential cross-sections vs. the electron energy, electron angle, and square of the four-momentum transferred to the nucleus, $Q^2$. We also compute the ratio to a muon neutrino cross-section in $Q^2$ from MINERvA. We find satisfactory agreement between this measurement and the predictions of the GENIE generator.

  5. Measurement of Electron Neutrino Quasielastic and Quasielasticlike Scattering on Hydrocarbon at ⟨E_{ν}⟩=3.6  GeV.

    PubMed

    Wolcott, J; Aliaga, L; Altinok, O; Bellantoni, L; Bercellie, A; Betancourt, M; Bodek, A; Bravar, A; Budd, H; Cai, T; Carneiro, M F; Chvojka, J; da Motta, H; Devan, J; Dytman, S A; Díaz, G A; Eberly, B; Felix, J; Fields, L; Fine, R; Gago, A M; Galindo, R; Gallagher, H; Ghosh, A; Golan, T; Gran, R; Harris, D A; Higuera, A; Kiveni, M; Kleykamp, J; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; Martinez Caicedo, D A; McFarland, K S; McGivern, C L; McGowan, A M; Messerly, B; Miller, J; Mislivec, A; Morfín, J G; Mousseau, J; Muhlbeier, T; Naples, D; Nelson, J K; Norrick, A; Osta, J; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ransome, R D; Ray, H; Ren, L; Rimal, D; Rodrigues, P A; Ruterbories, D; Salazar, G; Schellman, H; Schmitz, D W; Solano Salinas, C J; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wospakrik, M; Zavala, G; Zegarra, A; Zhang, D; Ziemer, B P

    2016-02-26

    The first direct measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in the electron production angle, electron energy, and Q^{2} are presented. The ratio of the quasielastic, flux-integrated differential cross section in Q^{2} for ν_{e} with that of similarly selected ν_{μ}-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current ν_{e} interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well described by the predictions of the neutrino event generator GENIE. PMID:26967410

  6. Measurement of Electron Neutrino Quasielastic and Quasielasticlike Scattering on Hydrocarbon at ⟨Eν⟩=3.6 GeV

    NASA Astrophysics Data System (ADS)

    Wolcott, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; Carneiro, M. F.; Chvojka, J.; da Motta, H.; Devan, J.; Dytman, S. A.; Díaz, G. A.; Eberly, B.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Kiveni, M.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; Martinez Caicedo, D. A.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Muhlbeier, T.; Naples, D.; Nelson, J. K.; Norrick, A.; Osta, J.; Paolone, V.; Park, J.; Patrick, C. E.; Perdue, G. N.; Rakotondravohitra, L.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Salazar, G.; Schellman, H.; Schmitz, D. W.; Solano Salinas, C. J.; Tagg, N.; Tice, B. G.; Valencia, E.; Walton, T.; Wospakrik, M.; Zavala, G.; Zegarra, A.; Zhang, D.; Ziemer, B. P.; Minerva Collaboration

    2016-02-01

    The first direct measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in the electron production angle, electron energy, and Q2 are presented. The ratio of the quasielastic, flux-integrated differential cross section in Q2 for νe with that of similarly selected νμ-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current νe interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well described by the predictions of the neutrino event generator GENIE.

  7. Computations of the collapse of a stellar iron core allowing for the absorption, emission, and scattering of electron neutrinos and anti-neutrinos

    NASA Astrophysics Data System (ADS)

    Aksenov, A. G.; Chechetkin, V. M.

    2012-03-01

    The collapse of the iron core of a star with mass 1.4 M ⊙ is computed. The initial model was chosen to be polytropic, P ∝ ρ 1+1/ n , with n = 3. The equation of state takes into account the equilibrium radiation of photons, a mixture of Fermi gases comprised of free nucleons and ideal gases comprised of nuclei (Fe, He) in equilibrium with respect to nuclear reactions, and electron-positron gas. The transport equation for electron neutrinos and anti-neutrinos is also included. The absorption and emission of neutrinos and anti-neutrinos with the participation of free nucleons and nuclei is taken into account, as well as scattering on electrons. The main goal of this study is to develop a numerical method for the joint solution of the gas-dynamical equations formatter and the Boltzmann kinetic equations for the distribution functions of various types of neutrinos in both optically thin and optically thick regions. The spherically symmetrical case is considered, but the dependences of the distribution functions on all the phase-space variables—the mass coordinate, particle energy, cosine of the angle between the radius vector and the particle momentum, and time, ( m, ɛ, µ, t)—are retained in the description of the neutrino transport. When computing reaction rates, the exact quantum-mechanical expressions for the probabilities of processes are used, with integration over the entire momentum phase space. The gas-dynamical variables depend on the mass coordinate and time, ( m, t). The solution yields neutrino light curves, which have narrow maximum with characteristic widths ≈10 ms. This makes it possible to place constraints on the mass of the electron neutrino based on the detection of short bursts of radiation, ≲4 eV. Part of the neutrino energy is absorbed in the envelope of the stellar core (˜1050 erg). This is associated with the higher mean neutrino energies in this model, which is more exact than models with neutrino thermal conductivity. This

  8. Energy Estimation for the NOvA Electron Neutrino Appearance Analysis

    NASA Astrophysics Data System (ADS)

    Psihas, Fernanda

    2016-03-01

    The NOvA experiment measures long baseline νμ -->νe oscillations in Fermilab's NuMI beam. Measurement of this oscillation probability enables determination of the neutrino mass ordering and opens a window to observation of charge-parity violation in the neutrino sector. NOvA started taking data in 2014 and has already observed νe appearance at the 3.3 σ level with the first 7 % of the total projected dataset last year. Future analyses will exploit the expected energy dependence of oscillation to improve sensitivity. A new method to estimate energy for νe events and its impact on the next analysis will be discussed.

  9. Measurement of the Charged-Current Quasi-Elastic Cross-Section for Electron Neutrinos on a Hydrocarbon Target

    SciTech Connect

    Wolcott, Jeremy

    2016-01-01

    Appearance-type neutrino oscillation experiments, which observe the transition from muon neutrinos to electron neutrinos, promise to help answer some of the fundamental questions surrounding physics in the post-Standard-Model era. Because they wish to observe the interactions of electron neutrinos in their detectors, and because the power of current results is typically limited by their systematic uncertainties, these experiments require precise estimates of the cross-section for electron neutrino interactions. Of particular interest is the charged-current quasi-elastic (CCQE) process, which gures signi cantly in the composition of the reactions observed at the far detector. However, no experimental measurements of this crosssection currently exist for electron neutrinos; instead, current experiments typically work from the abundance of muon neutrino CCQE cross-section data and apply corrections from theoretical arguments to obtain a prediction for electron neutrinos. Veri cation of these predictions is challenging due to the di culty of constructing an electron neutrino beam, but the advent of modern high-intensity muon neutrino beams|together with the percent-level electron neutrino impurity inherent in these beams| nally presents the opportunity to make such a measurement. We report herein the rst-ever measurement of a cross-section for an exclusive state in electron neutrino scattering, which was made using the MINER A detector in the NuMI neutrino beam at Fermilab. We present the electron neutrino CCQE di erential cross-sections, which are averaged over neutrinos of energies 1-10 GeV (with mean energy of about 3 GeV), in terms of various kinematic variables: nal-state electron angle, nal-state electron energy, and the square of the fourmomentum transferred to the nucleus by the neutrino , Q2. We also provide a total cross-section vs. neutrino energy. While our measurement of this process is found to be in agreement with the predictions of the GENIE

  10. Observation of electron neutrino appearance in a muon neutrino beam.

    PubMed

    Abe, K; Adam, J; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, S W; Berardi, V; Berger, B E; Berkman, S; Bertram, I; Bhadra, S; Blaszczyk, F D M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Caravaca Rodríguez, J; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dufour, F; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery, S; Ereditato, A; Escudero, L; Finch, A J; Floetotto, L; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Gaudin, A; Giffin, S; Giganti, C; Gilje, K; Goeldi, D; Golan, T; Gomez-Cadenas, J J; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Ives, S J; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Jung, C K; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; Kisiel, J; Kitching, P; Kobayashi, T; Koch, L; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kreslo, I; Kropp, W; Kubo, H; Kudenko, Y; Kumaratunga, S; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Lamont, I; Laveder, M; Lawe, M; Lazos, M; Lee, K P; Licciardi, C; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Ludovici, L; Macaire, M; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Maruyama, T; Marzec, J; Mathie, E L; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Metelko, C; Mezzetto, M; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Monfregola, L; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nagasaki, T; Nakadaira, T; Nakahata, M; Nakai, T; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Naples, D; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Owen, R A; Oyama, Y; Palladino, V; Paolone, V; Payne, D; Pearce, G F; Perevozchikov, O; Perkin, J D; Petrov, Y; Pickard, L J; Pinzon Guerra, E S; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J-M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Retiere, F; Robert, A; Rodrigues, P A; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smith, R J; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Szeglowski, T; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Ueno, K; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2014-02-14

    The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L. PMID:24580687

  11. Observation of Electron Neutrino Appearance in a Muon Neutrino Beam

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Floetotto, L.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Gaudin, A.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Licciardi, C.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Owen, R. A.; Oyama, Y.; Palladino, V.; Paolone, V.; Payne, D.; Pearce, G. F.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L. J.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2014-02-01

    The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm322 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm322|=2.4×10-3 eV2, sin2θ23=0.5, and Δm322>0 (Δm322<0), a best-fit value of sin22θ13=0.140-0.032+0.038 (0.170-0.037+0.045) is obtained at δCP=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ13 from reactor experiments, some values of δCP are disfavored at the 90% C.L.

  12. On the Measurement of the Electron-Neutrino Correlation in Neutron Beta Decay

    PubMed Central

    Bowman, J. David

    2005-01-01

    I present a new approach to the measurement of a, the electron-neutrino correlation, in neutron beta decay. A precise measurement of a can lead to a precise determination of ratio of the axial vector and vector coupling constants, Ga/Gv. Coincidences between electrons and protons are detected in a field-expansion spectrometer. The field-expansion spectrometer is designed to make 1/TOF ≈ | pp|. TOF and pp are the proton time of flight and momentum. Two segmented Si detectors view both electrons and protons in 4π geometry. The time of flight between the electron and proton are accurately measured in a long, ≈ 1 m, drift distance. The electron energy is accurately measured in the Si detectors. The proton momentum and electron energy determine the electron-neutrino opening angle. I have shown that by sorting the data on proton time of flight and electron energy, a can be determined with a statistical relative standard uncertainty of ≈2.4/n, where n is the number of decays observed. The approach has a number of advantages. The acceptance of the spectrometer is 4π for both particles. Thin-dead-layer segmented Si detectors as well as all other components in the apparatus, are commercially available. There are no material apertures to determine the acceptance of the apparatus. The charged particles interact only with electric and magnetic fields before striking the detectors. Coincident detection of electrons and protons reduces backgrounds, and allows the in situ determination of backgrounds. In the analysis, it is not necessary to sort on the relative electron and proton direction and hence electron back scattering does not cause systematic uncertainties. A time of flight spectrum is obtained for each electron energy. Different parts of the spectra have different sensitivities to a. The medium time of flight parts of the spectra that are insensitive to a can be used to verify the accuracy of the electric and magnetic field determinations. PMID:27308158

  13. Experiment to measure the electron neutrino mass using frozen tritium

    SciTech Connect

    Fackler, O.; Sticker, H.; Mugge, M.; White, R.M.; Woerner, R.

    1985-01-01

    We are performing an experiment to determine the electron neutrino mass with the precision of a few eV by measuring the tritium beta decay energy distribution near the endpoint. To make this measurement, we have built a spectrometer with a resolution of 2 eV. Our source is frozen tritium since tritium and the HeT/sup +/ daughter ion have electronic wavefunctions that can be calculated with high accuracy. We describe the experiment and discuss the excited final molecular state calculations.

  14. Experimental bound on the charge radius of the electron neutrino

    SciTech Connect

    Allen, R.C.; Chen, H.H.; Doe, P.J.; Hausamann, R.; Lee, W.P.; Lu, X.; Mahler, H.J.; Potter, M.E.; Wang, K.C. ); Bowles, T.J.; Burman, R.L.; Carlini, R.D.; Cochran, D.R.F.; Frank, J.S.; Piasetzky, E.; Sandberg, V.D. ); Krakauer, D.A.; Talaga, R.L. )

    1991-01-01

    A limit on the electron-neutrino charge radius {vert bar}{ital r}{vert bar} is derived from a measurement of the weak-neutral-current vector coupling constant {ital g}{sub {ital V}} obtained in electron-neutrino electron elastic scattering. The 90%-confidence interval for {ital g}{sub {ital V}} is {minus}0.177{lt}{ital g}{sub {ital V}}{lt}0.187, which for sin{sup 2}{theta}{sub {ital W}}=0.227 implies that the {nu}{sub {ital e}} mean-square charge radius is in the range {minus}2.74{times}10{sup {minus}32}{lt}{l angle}{ital r}{sup 2}{r angle}{lt}4.88{times}10{sup {minus}32} cm{sup 2}, or simply {vert bar}{ital r}{vert bar}{lt}2.2{times}10{sup {minus}16} cm. This is the first experimental bound on the {nu}{sub {ital e}} charge radius, and is the same order of magnitude as bounds for {nu}{sub {mu}} structure.

  15. Measurement of the Charged-Current Quasi-Elastic Cross-Section for Electron Neutrinos on a Hydrocarbon Target

    NASA Astrophysics Data System (ADS)

    Wolcott, Jeremy

    We report herein the first-ever measurement of a cross-section for an exclusive state in electron neutrino scattering at the GeV scale, which was made using the MINERnuA detector in the NuMI neutrino beam at Fermilab. We present the electron neutrino CCQE differential cross-sections, which are averaged over neutrinos of energies 1-10 GeV (with mean energy of about 3 GeV), in terms of various kinematic variables: final-state electron angle, final-state electron energy, and the square of the four-momentum transferred to the nucleus by the neutrino, Q2. We also provide a total cross-section vs. neutrino energy. While our measurement of this process is found to be in agreement with the predictions of the GENIE event generator, we also report on an unpredicted photon-like process we observe in a similar kinematic regime. The absence of this process from models for neutrino interactions is a potential stumbling block for future on-axis neutrino oscillation experiments. We include kinematic and particle species identification characterizations which can be used in building models to help address this shortcoming.

  16. An Upper Limit on the Electron-Neutrino Flux from the HiRes Detector

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abu-Zayyad, T.; Allen, M.; Amann, J. F.; Archbold, G.; Belov, K.; Belz, J. W.; Ben Zvi, S. Y.; Bergman, D. R.; Biesiadecka, A.; Blake, S. A.; Boyer, J. H.; Brusova, O. A.; Burt, G. W.; Cannon, C.; Cao, Z.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Gray, R. C.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G.; Hüntemeyer, P.; Ivanov, D.; Jones, B. F.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Knapp, B. C.; Loh, E. C.; Maestas, M. M.; Manago, N.; Mannel, E. J.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; Moore, S. A.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Rodriguez, D.; Sasaki, M.; Schnetzer, S. R.; Scott, L. M.; Seman, M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Wiencke, L. R.; Zech, A.; Zhang, X.

    2008-09-01

    Air-fluorescence detectors such as the High Resolution Fly's Eye (HiRes) detector are very sensitive to upward-going, Earth-skimming ultra-high-energy electron-neutrino-induced showers. This is due to the relatively large interaction cross sections of these high-energy neutrinos and to the Landau-Pomeranchuk-Migdal (LPM) effect. The LPM effect causes a significant decrease in the cross sections for bremsstrahlung and pair production, allowing charged-current electron-neutrino-induced showers occurring deep in the Earth's crust to be detectable as they exit the Earth into the atmosphere. A search for upward-going neutrino-induced showers in the HiRes-II monocular data set has yielded a null result. From an LPM calculation of the energy spectrum of charged particles as a function of primary energy and depth for electron-induced showers in rock, we calculate the shape of the resulting profile of these showers in air. We describe a full detector Monte Carlo simulation to determine the detector response to upward-going electron-neutrino-induced cascades and present an upper limit on the flux of electron neutrinos.

  17. Reines-Cowan team discovery of the electron neutrino

    NASA Astrophysics Data System (ADS)

    Kruse, Herald W.

    2011-12-01

    Personal perspective and recollections by the author discuss the Reines-Cowan team discovery of the electron neutrino at a Savannah River reactor in 1956. First presented at the Neutrino Santa Fe 2006 Conference.

  18. Electron-neutrino survival probability from solar-neutrino data

    NASA Astrophysics Data System (ADS)

    Berezinsky, V.; Lissia, M.

    2001-11-01

    With SNO data [SNO Collaboration, nucl-ex/0106015] on electron-neutrino flux from the sun, it is possible to derive the νe survival probability Pee(E) from existing experimental data of Super-Kamiokande, gallium experiments and Homestake. The combined data of SNO and Super-Kamiokande provide boron νe flux and the total flux of all active boron neutrinos, giving thus Pee(E) for boron neutrinos. The Homestake detector, after subtraction of the signal from boron neutrinos, gives the flux of Be/+CNO neutrinos, and Pee for the corresponding energy interval, if the produced flux is taken from the Standard Solar Model (SSM). Gallium detectors, GALLEX, SAGE and GNO, detect additionally /pp-neutrinos. The /pp flux can be calculated subtracting from the gallium signal the rate due to boron, beryllium and CNO neutrinos. The ratio of the measured /pp-neutrino flux to that predicted by the SSM gives the survival probability for /pp-neutrinos. Comparison with theoretical survival probabilities shows that the best (among known models) fit is given by LMA and LOW solutions.

  19. Measurement of the inclusive electron neutrino charged current cross section on carbon with the T2K near detector.

    PubMed

    Abe, K; Adam, J; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Berardi, V; Berger, B E; Berkman, S; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Caravaca Rodríguez, J; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Dewhurst, D; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery-Schrenk, S; Ereditato, A; Escudero, L; Finch, A J; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Giffin, S; Giganti, C; Gilje, K; Goeldi, D; Golan, T; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Iwai, E; Iwamoto, K; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; Kisiel, J; Kitching, P; Kobayashi, T; Koch, L; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koshio, Y; Kropp, W; Kubo, H; Kudenko, Y; Kurjata, R; Kutter, T; Lagoda, J; Lamont, I; Larkin, E; Laveder, M; Lawe, M; Lazos, M; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Ludovici, L; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Martynenko, S; Maruyama, T; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Metelko, C; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Missert, A; Miura, M; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nakadaira, T; Nakahata, M; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Owen, R A; Oyama, Y; Palladino, V; Palomino, J L; Paolone, V; Payne, D; Perevozchikov, O; Perkin, J D; Petrov, Y; Pickard, L; Pinzon Guerra, E S; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J-M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Rodrigues, P A; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schoppmann, S; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Żmuda, J

    2014-12-12

    The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1  GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³⁸ cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³⁸ cm²/nucleon and the GENIE prediction is 1.08×10⁻³⁸ cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment. PMID:25541766

  20. Measurement of the Inclusive Electron Neutrino Charged Current Cross Section on Carbon with the T2K Near Detector

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berger, B. E.; Berkman, S.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Ludovici, L.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2014-12-01

    The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ˜1 GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged νe charged current cross section on carbon is measured to be ⟨σ ⟩ϕ =1.11 ±0.10 (stat)±0.18 (syst)×1 0-38 cm2/nucleon . The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23 ×1 0-38 cm2/nucleon and the GENIE prediction is 1.08 ×1 0-38 cm2/nucleon . The total νe charged current cross-section result is also in agreement with data from the Gargamelle experiment.

  1. Observation of Electron Neutrino Appearance in the NuMI Beam with the NOvA Experiment

    SciTech Connect

    Niner, Evan David

    2015-01-01

    NOvA is a long-baseline neutrino oscillation experiment that uses two functionally identical detectors separated by 810 kilometers at locations 14 milliradians off-axis from the NuMI muon neutrino beam at Fermilab. At these locations the beam energy peaks at 2 GeV. This baseline is the longest in the world for an accelerator-based neutrino oscillation experiment, which enhances the sensitivity to the neutrino mass ordering. The experiment studies oscillations of the muon neutrino and anti-neutrino beam that is produced. Both detectors completed commissioning in the summer of 2014 and continue to collect data. One of the primary physics goals of the experiment is the measurement of electron neutrino appearance in the muon neutrino beam which yields measurements of the oscillation parameters sin213, δ , and the neutrino mass ordering within the standard model of neutrino oscillations. This thesis presents the analysis of data collected between February 2014 and May 2015, corresponding to 3.52 X 1020 protons-on-target. In this first analysis NOvA recorded 6 electron neutrino candidates, which is a 3.3σ observation of electron neutrino appearance. The T2K experiment performs the same measurement on a baseline of 295 kilometers and has a 1 σ preference for the normal mass ordering over the inverted ordering over the phase space of the CP violating parameter δ, which is also weakly seen in the NOvA result. By the summer of 2016 NOvA will triple its statistics due to increased beam power and a completed detector. If electron neutrinos continue to be observed at the current rate NOvA will be able to establish a mass ordering preference at a similar confidence level to T2K.

  2. An experiment to measure the electron neutrino mass using a cryogenic tritium source

    SciTech Connect

    Fackler, O.; Jeziorski, B.; Kolos, W.; Monkhorst, H.; Mugge, M.; Sticker, H.; Szalewicz, K.; White, R.M.; Woerner, R.

    1985-06-25

    An experiment has been performed to determine the electron neutrino mass with the precision of a few eV by measuring the tritium beta decay energy distribution near the endpoint. Key features of the experiment are a 2 eV resolution electrostatic spectrometer and a high-activity frozen tritium source. It is important that the source have electronic wavefunctions which can be accurately calculated. These calculations have been made for tritium and the HeT/sup +/ daughter ion and allow determination of branching fractions to 0.1% and energy of the excited states to 0.1 eV. The excited final molecular state calculations and the experimental apparatus are discussed. 4 refs., 5 figs.

  3. Detecting electron neutrinos from solar dark matter annihilation by JUNO

    NASA Astrophysics Data System (ADS)

    Guo, Wan-Lei

    2016-01-01

    We explore the electron neutrino signals from light dark matter (DM) annihilation in the Sun for the large liquid scintillator detector JUNO. In terms of the spectrum features of three typical DM annihilation channels χχ → νbar nu, τ+τ-, bbar b, we take two sets of selection conditions to calculate the expected signals and atmospheric neutrino backgrounds based on the Monte Carlo simulation data. Then the JUNO sensitivities to the spin independent DM-nucleon and spin dependent DM-proton cross sections are presented. It is found that the JUNO projected sensitivities are much better than the current spin dependent direct detection experimental limits for the νbar nu and τ+τ- channels. In the spin independent case, the JUNO will give the better sensitivity to the DM-nucleon cross section than the LUX and CDMSlite limits for the νbar nu channel with the DM mass lighter than 6.5 GeV . If the νbar nu or τ+τ- channel is dominant, the future JUNO results are very helpful for us to understand the tension between the DAMA annual modulation signal and other direct detection exclusions.

  4. Evidence for electron neutrino flavor change through measurement of the (8)B solar neutrino flux at the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Neubauer, Mark Stephen

    2001-11-01

    The Sudbury Neutrino Observatory (SNO) is a water Cerenkov detector designed to study solar neutrinos. Using 1 kiloton of heavy water as the target and detection medium, SNO is able to separately determine the flux of electron neutrinos (νe) and the flux of all active neutrinos from the Sun by measuring the rate of charged current (CC) and neutral current (NC) interactions with deuterons. A comparison of these interaction rates allows for direct observation of solar neutrino oscillations. SNO can also search for oscillations by comparing the rate of CC and neutrino- electron elastic scattering (ES) events, since ES has both charged current and neutral current sensitivity. In this thesis, we present measurement of the 8B solar ν e flux of 1.78+0.13-0.14 (stat+syst) × 106cm-2s -1 (35% BP2000 SSM) through measurement of the CC rate over 169.3 days of livetime. We have also measured the 8B flux from the ES reaction to be 2.56+0.48-0.45 (stat+syst), consistent with measurements by previous water Cerenkov experiments. A flavor analysis comparing the CC measured flux with that determined through ES by SuperKamiokande yields a non- νe active neutrino flux from 8B of 3.62+1.06-1.08 × 106cm-2s-1 , providing evidence for νe --> ν μ,τ oscillations as a solution to the solar neutrino problem. This result excludes pure solar νe --> ν s oscillations at greater than the 99.7% C.I. The total active 8B neutrino flux has been measured to be 5.39+1.07-1.09 × 106cm-2s-1 , consistent with BP2000 SSM predictions. First analyses of the CC (NHit) spectrum and hep flux in SNO are presented. The CC spectrum is found to be a good fit to expectations from an undistorted 8B spectrum, and global best fit vacuum oscillation solutions are disfavored over the other solutions by the data. Through observations near the 8B endpoint with consideration of energy systematics, hep flux limits of 4.1 (90% C.I.) and 6.9 (99% C.I.) times SSM expectations are obtained. A statistical fit for the

  5. Experimental evidence of electron neutrino oscillations and validation of MSW-LMA model with Borexino

    NASA Astrophysics Data System (ADS)

    Avanzini, M. Buizza

    2011-04-01

    We report the real time measurements of 7Be and 8B solar neutrino fluxes performed with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. The achievement of these measurements was possible thanks to the excellent levels of the radiopurity reached. The measurement of the 7Be in real time is the first direct measurements of the survival probability for solar electron neutrinos in the vacuum region. For 8B we reached a threshold energy of 3MeV which is the lowest achieved so far in real time. For the first time, the same apparatus can measure two different oscillation regions (vacuum-driven and matter-enhanced) predicted by the MSW-LMA model. Borexino also quotes the ratio between the survival probabilities, corresponding to 1.93 ± 0.75, and validates the presence of the transition region between the two oscillation regimes, according to the MSW-LMA solution.In addition, a preliminary result on the Day-Night Asymmetry (ADN) for the 7Be neutrino flux is presented and corresponds to 0.007 ± 0.073. This measurement makes Borexino able to give once more an independent confirmation of the MSW-LMA solution.

  6. Zero energy scattering calculation in Euclidean space

    NASA Astrophysics Data System (ADS)

    Carbonell, J.; Karmanov, V. A.

    2016-03-01

    We show that the Bethe-Salpeter equation for the scattering amplitude in the limit of zero incident energy can be transformed into a purely Euclidean form, as it is the case for the bound states. The decoupling between Euclidean and Minkowski amplitudes is only possible for zero energy scattering observables and allows determining the scattering length from the Euclidean Bethe-Salpeter amplitude. Such a possibility strongly simplifies the numerical solution of the Bethe-Salpeter equation and suggests an alternative way to compute the scattering length in Lattice Euclidean calculations without using the Luscher formalism. The derivations contained in this work were performed for scalar particles and one-boson exchange kernel. They can be generalized to the fermion case and more involved interactions.

  7. Simulation of low-energy ion scattering

    NASA Astrophysics Data System (ADS)

    Langelaar, M. H.; Breeman, M.; Mijiritskii, A. V.; Boerma, D. O.

    A new simulation program `MATCH' has been developed for a detailed analysis of low-energy ion scattering (LEIS) and recoiling data. Instead of performing the full calculation of the three-dimensional trajectories through the sample from the ion source towards the detector, incoming trajectories as well as reversed-time outgoing trajectories are calculated, separately. Finally, these trajectories are matched to obtain the yield. The program has been tested for spectra and azimuthal scans of scattering and recoiling events of various sample species in different scattering geometries.

  8. Ultrahigh-energy neutrino scattering

    NASA Astrophysics Data System (ADS)

    Kuroda, Masaaki; Schildknecht, Dieter

    2013-09-01

    We predict the neutrino-nucleon cross section at ultrahigh energies relevant in connection with the search for high-energy cosmic neutrinos. Our investigation, employing the color-dipole picture, among other things, allows us to quantitatively determine which fraction of the ultrahigh-energy neutrino-nucleon cross section stems from the saturation vs the color-transparency region. We disagree with various results in the literature that predict a strong suppression of the neutrino-nucleon cross section at neutrino energies above E≅109GeV. Suppression in the sense of a diminished increase of the neutrino-nucleon cross section with energy only starts to occur at neutrino energies beyond E≅1014GeV.

  9. Attenuation of Scattered Thermal Energy Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Seroka, Katelyn T.; McPhate, Jason B.; Miller, Sharon K.

    2011-01-01

    The attenuation of scattered thermal energy atomic oxygen is relevant to the potential damage that can occur within a spacecraft which sweeps through atomic oxygen in low Earth orbit (LEO). Although there can be significant oxidation and resulting degradation of polymers and some metals on the external surfaces of spacecraft, there are often openings on a spacecraft such as telescope apertures, vents, and microwave cavities that can allow atomic oxygen to enter and scatter internally to the spacecraft. Atomic oxygen that enters a spacecraft can thermally accommodate and scatter to ultimately react or recombine on surfaces. The atomic oxygen that does enter a spacecraft can be scavenged by use of high erosion yield polymers to reduce its reaction on critical surfaces and materials. Polyoxymethylene and polyethylene can be used as effective atomic oxygen scavenging polymers.

  10. Computational Study of Low Energy Nuclear Scattering

    NASA Astrophysics Data System (ADS)

    Salazar, Justin; Hira, Ajit; Brownrigg, Clifton; Pacheco, Jose

    2013-04-01

    We continue our interest in the interactions between different nuclear species with a computational study of the scattering of the low-energy nuclei of H through F atoms ( Z<=9 ) from Palladium and other metals. First, a FORTRAN computer program was developed to compute stopping cross sections and scattering angles in Pd and other metals for the small nuclear projectiles, using Monte Carlo calculation. This code allows for different angles of incidence. Next, simulations were done in the energy interval from 10 to 140kev. The computational results thus obtained are compared with relevant experimental data. The data are further analyzed to identify periodic trends in terms of the atomic number of the projectile. Such studies have potential applications in nuclear physics and in nuclear medicine.

  11. Low Energy Electron Scattering from Fuels

    NASA Astrophysics Data System (ADS)

    Lopes, M. C. A.; Silva, D. G. M.; Bettega, M. H. F.; da Costa, R. F.; Lima, M. A. P.; Khakoo, M. A.; Winstead, C.; McKoy, V.

    2012-11-01

    In order to understand and optimize processes occurring during the ignition of plasma and its consequences in post-discharge for an internal combustion engine, especially considering the spark plug, we have produced in this work some basic information necessary to modeling spark ignition in alcohol- fuelled engines. Total cross sections of electron scattering by methanol and ethanol molecules in the energy range from 60 to 500 eV are reported, using the linear transmission method based on the Beer-Lambert law to first approximation. Aditionally to that, measurements and calculations of differential cross sections for elastic low-energy (rotationally unresolved) electron scattering were also discussed, for impact energies of 1, 2, 5, 10, 15, 20, 30, 50, and 100 eV and for scattering angles of 5°-130°. The measurements were obtained using the relative flow method with an aperture source, and calculations using two different implementations of the Schwinger multichannel method, one that takes all electrons into account and is adapted for parallel computers, and another that uses pseudopotentials and considers only the valence electrons.

  12. Low energy Skyrmion-Skyrmion scattering

    SciTech Connect

    Gisiger, T.; Paranjape, M.B. )

    1994-07-15

    We study the scattering of two Skyrmions at low energy and large separation. We use the method proposed by Manton for truncating the degrees of freedom of the system from infinite to a manageable finite number. This corresponds to identifying the manifold consisting of the union of the low energy critical points of the potential along with the gradient flow curves joining these together and by positing that the dynamics is restricted here. The kinetic energy provides an induced metric on this manifold while restricting the full potential energy to the manifold defines a potential. The low energy dynamics is now constrained to these finite number of degrees of freedom. For a large separation of the two Skyrmions the manifold is parametrized by the variables of the product ansatz. We find the interaction between two Skyrmions coming from the induced metric, which was independently found by Schroers. We find that the static potential is actually negligible in comparison to this interaction. Thus to lowest order, at large separation, the dynamics reduces to geodesic motion on the manifold. We consider the scattering to first order in the interaction using the perturbative method of Lagrange and find that the dynamics in the no spin or charge exchange sector reduces to the Kepler problem.

  13. Low energy Skyrmion-Skyrmion scattering

    NASA Astrophysics Data System (ADS)

    Gisiger, T.; Paranjape, M. B.

    1994-07-01

    We study the scattering of two Skyrmions at low energy and large separation. We use the method proposed by Manton for truncating the degrees of freedom of the system from infinite to a manageable finite number. This corresponds to identifying the manifold consisting of the union of the low energy critical points of the potential along with the gradient flow curves joining these together and by positing that the dynamics is restricted here. The kinetic energy provides an induced metric on this manifold while restricting the full potential energy to the manifold defines a potential. The low energy dynamics is now constrained to these finite number of degrees of freedom. For a large separation of the two Skyrmions the manifold is parametrized by the variables of the product ansatz. We find the interaction between two Skyrmions coming from the induced metric, which was independently found by Schroers. We find that the static potential is actually negligible in comparison to this interaction. Thus to lowest order, at large separation, the dynamics reduces to geodesic motion on the manifold. We consider the scattering to first order in the interaction using the perturbative method of Lagrange and find that the dynamics in the no spin or charge exchange sector reduces to the Kepler problem.

  14. Low-energy pion-nucleon scattering

    NASA Astrophysics Data System (ADS)

    Gibbs, W. R.; Ai, Li; Kaufmann, W. B.

    1998-02-01

    An analysis of low-energy charged pion-nucleon data from recent π+/-p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f2=0.0756+/-0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P31 and P13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided.

  15. Low-energy pion-nucleon scattering

    SciTech Connect

    Gibbs, W.R.; Ai, L.; Kaufmann, W.B.

    1998-02-01

    An analysis of low-energy charged pion-nucleon data from recent {pi}{sup {plus_minus}}p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f{sup 2}=0.0756{plus_minus}0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P{sub 31} and P{sub 13} partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the {Sigma} term. Off-shell amplitudes are also provided. {copyright} {ital 1998} {ital The American Physical Society}

  16. Low energy scattering with a nontrivial pion

    SciTech Connect

    Fariborz, Amir H.

    2007-12-01

    An earlier calculation in a generalized linear sigma model showed that the well-known current algebra formula for low energy pion-pion scattering held even though the massless Nambu Goldstone pion contained a small admixture of a two-quark two-antiquark field. Here we turn on the pion mass and note that the current algebra formula no longer holds exactly. We discuss this small deviation and also study the effects of a SU(3) symmetric quark mass type term on the masses and mixings of the eight SU(3) multiplets in the model. We calculate the s-wave scattering lengths, including the beyond current algebra theorem corrections due to the scalar mesons, and observe that the effect of the scalar mesons is to improve the agreement with experiment. In the process, we uncover the way in which linear sigma models give controlled corrections (due to the presence of scalar mesons) to the current algebra scattering formula. Such a feature is commonly thought to exist only in the nonlinear sigma model approach.

  17. Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 π0 detector

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bartet-Friburg, P.; Bass, M.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berger, B. E.; Berkman, S.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bolognesi, S.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Chikuma, N.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Dolan, S.; Drapier, O.; Duffy, K.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Escudero, L.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haegel, L.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Hosomi, F.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Jiang, M.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; King, S.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Koga, T.; Kolaceke, A.; Konaka, A.; Kopylov, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, J. P.; Ludovici, L.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Riccio, C.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Rychter, A.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J. D.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaikhiev, A.; Shaker, F.; Shaw, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoo, J.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2015-06-01

    This paper presents a measurement of the charged current interaction rate of the electron neutrino beam component of the beam above 1.5 GeV using the large fiducial mass of the T2K π0 detector. The predominant portion of the νe flux (˜85 % ) at these energies comes from kaon decays. The measured ratio of the observed beam interaction rate to the predicted rate in the detector with water targets filled is 0.89 ±0.08 (stat)±0.11 (sys) , and with the water targets emptied is 0.90 ±0.09 (stat)±0.13 (sys) . The ratio obtained for the interactions on water only from an event subtraction method is 0.87 ±0.33 (stat)±0.21 (sys) . This is the first measurement of the interaction rate of electron neutrinos on water, which is particularly of interest to experiments with water Cherenkov detectors.

  18. Measurement of interference between W and Z exchange in electron-neutrino electron scattering

    SciTech Connect

    Allen, R.C.; Chen, H.H.; Doe, P.J.; Hausammann, R.; Lee, W.P.; Mahler, H.J.; Potter, M.E.; Lu, X.Q.; Wang, K.C. ); Bowles, T.J.; Burman, R.L.; Carlini, R.D.; Cochran, D.R.F.; Frank, J.S.; Piasetzky, E.; Sandberg, V.D. ); Krakauer, D.A.; Talaga, R.L. )

    1990-03-19

    A measurement of the reaction {nu}{sub {ital e}}+{ital e}{sup {minus}}{r arrow}{nu}{sub {ital e}}+{ital e}{sup {minus}} was performed using a beam-stop source of {nu}{sub {ital e}}. Based upon 234{plus minus}35 events, we obtain a cross section of {sigma}({nu}{sub {ital ee}})=(9.9{plus minus}1.5(stat){plus minus}1.0(syst)){times}10{sup {minus}42} cm{sup 2} {times}({ital E}{sub {nu}} (GeV)). This reaction is mediated by the exchange of {ital W} and {ital Z} bosons and is thus sensitive to the interference between them. This interference is measured to be {minus}1.07{plus minus}0.17(stat){plus minus}0.11(syst), consistent with the destructive interference ({minus}1.08) predicted by the standard model.

  19. New results for muon neutrino to electron neutrino oscillations in the MINOS experiment

    SciTech Connect

    Evans, Justin; Whitehead, Lisa; /Brookhaven

    2010-01-01

    MINOS is a long-baseline neutrino oscillation experiment situated along Fermilab's high-intensity NuMI neutrino beam. MINOS has completed an updated search for muon neutrino to electron neutrino transitions, observation of which would indicate a non-zero value for the neutrino mixing angle {theta}{sub 13}. The present 7 x 10{sup 20} protons-on-target data set represents more than double the exposure used in the previous analysis. The new result and its implications are presented.

  20. Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Floetotto, L.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iwai, E.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2014-05-01

    The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01±0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately measured, resulting in a ratio with respect to the prediction of 0.68±0.30 and 1.10±0.14, respectively.

  1. Deep Wavelet Scattering for Quantum Energy Regression

    NASA Astrophysics Data System (ADS)

    Hirn, Matthew

    Physical functionals are usually computed as solutions of variational problems or from solutions of partial differential equations, which may require huge computations for complex systems. Quantum chemistry calculations of ground state molecular energies is such an example. Indeed, if x is a quantum molecular state, then the ground state energy E0 (x) is the minimum eigenvalue solution of the time independent Schrödinger Equation, which is computationally intensive for large systems. Machine learning algorithms do not simulate the physical system but estimate solutions by interpolating values provided by a training set of known examples {(xi ,E0 (xi) } i <= n . However, precise interpolations may require a number of examples that is exponential in the system dimension, and are thus intractable. This curse of dimensionality may be circumvented by computing interpolations in smaller approximation spaces, which take advantage of physical invariants. Linear regressions of E0 over a dictionary Φ ={ϕk } k compute an approximation E 0 as: E 0 (x) =∑kwkϕk (x) , where the weights {wk } k are selected to minimize the error between E0 and E 0 on the training set. The key to such a regression approach then lies in the design of the dictionary Φ. It must be intricate enough to capture the essential variability of E0 (x) over the molecular states x of interest, while simple enough so that evaluation of Φ (x) is significantly less intensive than a direct quantum mechanical computation (or approximation) of E0 (x) . In this talk we present a novel dictionary Φ for the regression of quantum mechanical energies based on the scattering transform of an intermediate, approximate electron density representation ρx of the state x. The scattering transform has the architecture of a deep convolutional network, composed of an alternating sequence of linear filters and nonlinear maps. Whereas in many deep learning tasks the linear filters are learned from the training data, here

  2. Quasi-elastic nuclear scattering at high energies

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

    1992-01-01

    The quasi-elastic scattering of two nuclei is considered in the high-energy optical model. Energy loss and momentum transfer spectra for projectile ions are evaluated in terms of an inelastic multiple-scattering series corresponding to multiple knockout of target nucleons. The leading-order correction to the coherent projectile approximation is evaluated. Calculations are compared with experiments.

  3. Scattering with absorptive interaction: Energy-dependent potentials

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1983-05-01

    The energy dependence and analytic structure of the effective interaction for elastic scattering of composite particles are investigated using Feshbach's projection technique. A generalized Levinson theorem is established for complex, nonlocal, and energy-dependent interactions. The analytical results are illustrated by means of Argand diagrams for a solvable model and the effect of energy averaging is discussed. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive, energy-dependent potentials, Levinson theorem.

  4. Intermediate energy proton-deuteron elastic scattering

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1973-01-01

    A fully symmetrized multiple scattering series is considered for the description of proton-deuteron elastic scattering. An off-shell continuation of the experimentally known twobody amplitudes that retains the exchange symmeteries required for the calculation is presented. The one boson exchange terms of the two body amplitudes are evaluated exactly in this off-shell prescription. The first two terms of the multiple scattering series are calculated explicitly whereas multiple scattering effects are obtained as minimum variance estimates from the 146-MeV data of Postma and Wilson. The multiple scattering corrections indeed consist of low order partial waves as suggested by Sloan based on model studies with separable interactions. The Hamada-Johnston wave function is shown consistent with the data for internucleon distances greater than about 0.84 fm.

  5. Algorithmic scatter correction in dual-energy digital mammography

    SciTech Connect

    Chen, Xi; Mou, Xuanqin; Nishikawa, Robert M.; Lau, Beverly A.; Chan, Suk-tak; Zhang, Lei

    2013-11-15

    Purpose: Small calcifications are often the earliest and the main indicator of breast cancer. Dual-energy digital mammography (DEDM) has been considered as a promising technique to improve the detectability of calcifications since it can be used to suppress the contrast between adipose and glandular tissues of the breast. X-ray scatter leads to erroneous calculations of the DEDM image. Although the pinhole-array interpolation method can estimate scattered radiations, it requires extra exposures to measure the scatter and apply the correction. The purpose of this work is to design an algorithmic method for scatter correction in DEDM without extra exposures.Methods: In this paper, a scatter correction method for DEDM was developed based on the knowledge that scattered radiation has small spatial variation and that the majority of pixels in a mammogram are noncalcification pixels. The scatter fraction was estimated in the DEDM calculation and the measured scatter fraction was used to remove scatter from the image. The scatter correction method was implemented on a commercial full-field digital mammography system with breast tissue equivalent phantom and calcification phantom. The authors also implemented the pinhole-array interpolation scatter correction method on the system. Phantom results for both methods are presented and discussed. The authors compared the background DE calcification signals and the contrast-to-noise ratio (CNR) of calcifications in the three DE calcification images: image without scatter correction, image with scatter correction using pinhole-array interpolation method, and image with scatter correction using the authors' algorithmic method.Results: The authors' results show that the resultant background DE calcification signal can be reduced. The root-mean-square of background DE calcification signal of 1962 μm with scatter-uncorrected data was reduced to 194 μm after scatter correction using the authors' algorithmic method. The range of

  6. Scattered surface wave energy in the seismic coda

    USGS Publications Warehouse

    Zeng, Y.

    2006-01-01

    One of the many important contributions that Aki has made to seismology pertains to the origin of coda waves (Aki, 1969; Aki and Chouet, 1975). In this paper, I revisit Aki's original idea of the role of scattered surface waves in the seismic coda. Based on the radiative transfer theory, I developed a new set of scattered wave energy equations by including scattered surface waves and body wave to surface wave scattering conversions. The work is an extended study of Zeng et al. (1991), Zeng (1993) and Sato (1994a) on multiple isotropic-scattering, and may shed new insight into the seismic coda wave interpretation. The scattering equations are solved numerically by first discretizing the model at regular grids and then solving the linear integral equations iteratively. The results show that scattered wave energy can be well approximated by body-wave to body wave scattering at earlier arrival times and short distances. At long distances from the source, scattered surface waves dominate scattered body waves at surface stations. Since surface waves are 2-D propagating waves, their scattered energies should in theory follow a common decay curve. The observed common decay trends on seismic coda of local earthquake recordings particular at long lapse times suggest that perhaps later seismic codas are dominated by scattered surface waves. When efficient body wave to surface wave conversion mechanisms are present in the shallow crustal layers, such as soft sediment layers, the scattered surface waves dominate the seismic coda at even early arrival times for shallow sources and at later arrival times for deeper events.

  7. Inelastic x-ray scattering at modest energy resolution

    SciTech Connect

    Finkelstein, K. D.; Tischler, J. Z.; Larson, B. C.

    1997-07-01

    We report results from the development of an inelastic scattering spectrometer designed to take advantage of high energy synchrotron radiation available at CHESS. The device allows a large increase of the effective scattering volume in the sample by permitting measurements to be made in an energy range up to 25 KeV. The highest useable energy appears limited by the efficiency of the analyzers under consideration. At 20 KeV a novel 4-bounce, sagittal focusing monochromator passes 10e11 photons/second with Darwin width limited energy resolution. In the scattering plane, the monochromator images the electron beam producing a small scattering source for the analyzing optics. Analyzer systems under study include a cooled mosaic crystal in para-focusing geometry, and an adjustable spherically bent silicon crystal respectively for parallel and point-by-point collection of the energy loss spectrum. This paper discusses the optical configurations presents results from our early measurements and suggests directions for improvements.

  8. A search for muon neutrino to electron neutrino oscillations in the MINOS Experiment

    SciTech Connect

    Ochoa Ricoux, Juan Pedro

    2009-01-01

    We perform a search for vμ → ve oscillations, a process which would manifest a nonzero value of the θ13 mixing angle, in the MINOS long-baseline neutrino oscillation experiment. The analysis consists of searching for an excess of ve charged-current candidate events over the predicted backgrounds, made mostly of neutral-current events with high electromagnetic content. A novel technique to select electron neutrino events is developed, which achieves an improved separation between the signal and the backgrounds, and which consequently yields a better reach in θ13. The backgrounds are predicted in the Far Detector from Near Detector measurements. An excess is observed in the Far Detector data over the predicted backgrounds, which is consistent with the background-only hypothesis at 1.2 standard deviations.

  9. High energy-resolution inelastic x-ray scattering

    SciTech Connect

    Hastings, J.B.; Moncton, D.E.; Fujii

    1984-01-01

    A brief review is presented of various aspects of high energy-resolution inelastic x-ray scattering based on synchrotron sources. We show what kinematical advantages are provided by the photon probe and propose mirror and monochromator designs to achieve an optically efficient beam line for inelastic x-ray scattering.

  10. Observing Muon Neutrino to Electron Neutrino Oscillations in the NOνA Experiment

    SciTech Connect

    Xin, Tian

    2016-01-01

    Neutrino oscillations offers an insight on new physics beyond the Standard Model. The three mixing angles (θ12, θ13 and θ23) and the two mass splittings (Δm2 and Αm2 ) have been measured by different neutrino oscillation experiments. Some other parameters including the mass ordering of different neutrino mass eigenstates and the CP violation phase are still unknown. NOνA is a long-baseline accelerator neutrino experiment, using neutrinos from the NuMI beam at Fermilab. The experiment is equipped with two functionally identical detectors about 810 kilometers apart and 14 mrad off the beam axis. In this configuration, the muon neutrinos from the NuMI beam reach the disappearance maximum in the far detector and a small fraction of that oscillates into electron neutrinos. The sensitivity to the mass ordering and CP viola- tion phase determination is greately enhanced. This thesis presents the νeappearance analysis using the neutrino data collected with the NOνA experiment between February 2014 and May 2015, which corresponds to 3.45 ×1020 protons-on-target (POT). The νe appearance analysis is performed by comparing the observed νe CC-like events to the estimated background at the far detector. The total background is predicted to be 0.95 events with 0.89 originated from beam events and 0.06 from cosmic ray events. The beam background is obtained by extrapolating near detector data through different oscillation channels, while the cosmic ray background is calculated based on out-of-time NuMI trigger data. A total of 6 electron neutrino candidates are observed in the end at the far detector which represents 3.3 σ excess over the predicted background. The NOνA result disfavors inverted mass hierarchy for δcp ϵ [0, 0.6π] at 90% C.L.

  11. Rashba scattering in the low-energy limit

    NASA Astrophysics Data System (ADS)

    Hutchinson, Joel; Maciejko, Joseph

    2016-06-01

    We study potential scattering in a two-dimensional electron gas with Rashba spin-orbit coupling in the limit that the energy of the scattering electron approaches the bottom of the lower spin-split band. Focusing on two spin-independent circularly symmetric potentials, an infinite barrier and a delta-function shell, we show that scattering in this limit is qualitatively different from both scattering in the higher spin-split band and scattering of electrons without spin-orbit coupling. The scattering matrix is purely off-diagonal with both off-diagonal elements equal to one, and all angular momentum channels contribute equally; the differential cross section becomes increasingly peaked in the forward and backward scattering directions; the total cross section exhibits quantized plateaus. These features are independent of the details of the scattering potentials, and we conjecture them to be universal. Our results suggest that Rashba scattering in the low-energy limit becomes effectively one-dimensional.

  12. Energy distribution of elastically scattered electrons from double layer samples

    NASA Astrophysics Data System (ADS)

    Tőkési, K.; Varga, D.

    2016-02-01

    We present a theoretical description of the spectra of electrons elastically scattered from thin double layered Au-C samples. The analysis is based on the Monte Carlo simulation of the recoil and Doppler effects in reflection and transmission geometries of the scattering at a fixed angle of 44.3 ° and a primary energy of 40 keV. The relativistic correction is taken into account. Besides the experimentally measurable energy distributions the simulations give many partial distributions separately, depending on the number of elastic scatterings (single, and multiple scatterings of different types). Furthermore, we present detailed analytical calculations for the main parameters of the single scattering, taking into account both the ideal scattering geometry, i.e. infinitesimally small angular range, and the effect of the real, finite angular range used in the measurements. We show our results for intensity ratios, peak shifts and broadenings for four cases of measurement geometries and layer thicknesses. While in the peak intensity ratios of gold and carbon for transmission geometries were found to be in good agreement with the results of the single scattering model, especially large deviations were obtained in reflection geometries. The separation of the peaks, depending on the geometry and the thickness, generally smaller, and the peak width generally larger than it can be expected from the nominal values of the primary energy, scattering angle, and mean kinetic energy of the atoms. We also show that the peaks are asymmetric even for the case of the single scattering due to the finite solid angle. Finally, we present a qualitative comparison with the experimental data. We find our resulting energy distribution of elastically scattered electrons to be in good agreement with recent measurements.

  13. A surface-scattering model satisfying energy conservation and reciprocity

    NASA Astrophysics Data System (ADS)

    Sasihithlu, Karthik; Dahan, Nir; Hugonin, Jean-Paul; Greffet, Jean-Jacques

    2016-03-01

    Roughness scattering models based on Kirchhoff's approximation or perturbation theory give a good account of the angular distribution of the scattered intensity but do not satisfy energy conservation and reciprocity rigorously. For applications such as solar cells with rough interfaces producing a quasi isotropic intensity in the multiple scattering regime, an accurate model of the angular pattern is not required. Instead, energy conservation and reciprocity must be satisfied with great accuracy. Here we present a surface scattering model based on analysis of scattering from a layer of particles on top of a substrate in the dipole approximation which satisfies both energy conservation and reciprocity and is thus accurate in all frequency ranges. The model takes into account the absorption in the substrate induced by the particles but does not take into account the near-field interactions between the particles. In arriving at this model, we use the effective-medium approach to show how we can proceed from modeling the electromagnetic scattering from a single particle to modeling the scattering from a layer of particles positioned above a substrate, and finally relate this to the bidirectional scattering distribution function of the substrate.

  14. Kaon-nuclear scattering at medium energies

    SciTech Connect

    Eisenstein, R.A.

    1981-01-01

    A brief review of kaon-nucleus scattering is given. The discussion includes an account of recent theoretical interpretations of existing elastic and inelastic data, as well as possible directions for future study. The current experimental facility at Brookhaven is described, and an outline of future progress in this area is presented.

  15. Low-energy scattering of electrons and positrons in liquids

    NASA Technical Reports Server (NTRS)

    Schrader, D. M.

    1990-01-01

    The scattering of low energy electrons and positrons is described for the liquid phase and compared and contrasted with that for the gas phase. Similarities as well as differences are noted. The loci of scattering sites, called spurs in the liquid phase, are considered in detail. In particular, their temporal and spatial evolution is considered from the point of view of scattering. Two emphases are made: one upon the stochastic calculation of the distribution of distances required for slowing down to thermal velocities, and the other upon the calculation of cross sections for energy loss by means of quantum mechanics.

  16. Nucleus-nucleus scattering at high energies

    NASA Technical Reports Server (NTRS)

    Franco, V.; Varma, G. K.

    1977-01-01

    Nucleus-nucleus scattering is treated in the Glauber approximation. The usual optical limit result, generally thought to improve as the number of nucleons in the colliding nuclei increases, is found to be the first term of a series which diverges for large nuclei. Corrections to the optical limit are obtained which provide a means of performing realistic calculations for collisions involving light nuclei. Total cross section predictions agree well with recent measurements.

  17. High-energy photon-hadron scattering in holographic QCD

    SciTech Connect

    Nishio, Ryoichi; Watari, Taizan

    2011-10-01

    This article provides an in-depth look at hadron high-energy scattering by using gravity dual descriptions of strongly coupled gauge theories. Just like deeply inelastic scattering (DIS) and deeply virtual Compton scattering (DVCS) serve as clean experimental probes into nonperturbative internal structure of hadrons, elastic scattering amplitude of a hadron and a (virtual) photon in gravity dual can be exploited as a theoretical probe. Since the scattering amplitude at sufficiently high energy (small Bjorken x) is dominated by parton contributions (=Pomeron contributions) even in strong coupling regime, there is a chance to learn a lesson for generalized parton distribution (GPD) by using gravity dual models. We begin with refining derivation of the Brower-Polchinski-Strassler-Tan (BPST) Pomeron kernel in gravity dual, paying particular attention to the role played by the complex spin variable j. The BPST Pomeron on warped spacetime consists of a Kaluza-Klein tower of 4D Pomerons with nonlinear trajectories, and we clarify the relation between Pomeron couplings and the Pomeron form factor. We emphasize that the saddle-point value j* of the scattering amplitude in the complex j-plane representation is a very important concept in understanding qualitative behavior of the scattering amplitude. The total Pomeron contribution to the scattering is decomposed into the saddle-point contribution and at most a finite number of pole contributions, and when the pole contributions are absent (which we call saddle-point phase), kinematical variable (q,x,t)-dependence of ln(1/q) evolution and ln(1/x) evolution parameters {gamma}{sub eff} and {lambda}{sub eff} in DIS and t-slope parameter B of DVCS in HERA experiment are all reproduced qualitatively in gravity dual. All of these observations shed a new light on modeling of GPD. Straightforward application of those results to other hadron high-energy scattering is also discussed.

  18. Inferring mixture Gibbs free energies from static light scattering data

    NASA Astrophysics Data System (ADS)

    Ross, David; Wahle, Christopher; Thurston, George

    We describe a light scattering partial differential equation for the free energy of mixing that applies to connected, isotropic ternary and quaternary liquid composition domains, including restricted domains which may not touch all binary axes. For restricted domains, contrasting light scattering efficiency patterns obtained at different wavelengths can correspond to the same underlying free energy, and supplement the available information. We discuss well-posed problems for this fully nonlinear, degenerate elliptic partial differential equation. Using Monte Carlo simulations, we provide estimates of the overall system measurement time and sample spacing needed to determine the free energy to a desired degree of accuracy, and indicate how measurement time depends on instrument throughput. These methods provide a way to use static light scattering to measure, directly, mixing free energies of many systems that contain liquid domains. Supported by NIH EY018249.

  19. Elastic positron-cadmium scattering at low energies

    SciTech Connect

    Bromley, M. W. J.; Mitroy, J.

    2010-05-15

    The elastic and annihilation cross sections for positron-cadmium scattering are reported up to the positronium-formation threshold (at 2.2 eV). The low-energy phase shifts for the elastic scattering of positrons from cadmium were derived from the bound and pseudostate energies of a very large basis configuration-interaction calculation of the e{sup +}-Cd system. The s-wave binding energy is estimated to be 126{+-}42 meV, with a scattering length of A{sub scat}=(14.2{+-}2.1)a{sub 0}, while the threshold annihilation parameter, Z{sub eff}, was 93.9{+-}26.5. The p-wave phase shift exhibits a weak shape resonance that results in a peak Z{sub eff} of 91{+-}17 at a collision energy of about 490{+-}50 meV.

  20. High energy parton-parton elastic scattering in QCD

    SciTech Connect

    Tang, W.K.

    1993-08-01

    We show that the high energy limit of quark-quark, or gluon-gluon, elastic scattering is calculable in terms of the BFKL pomeron when {minus}t {much_gt} {Lambda}{sub QCD}{sup 2}. Surprisingly, this on-shell amplitudes does not have infrared divergences in the high energy limit.

  1. New results in nucleon-nucleon scattering at intermediate energies

    SciTech Connect

    Spinka, H.

    1995-01-01

    Many np elastic scattering spin observables have recently been measured between kinetic energies of about 500 and 1100 MeV at Saclay and LAMPF. These data are summarized and some new results are presented. Evidence for structure in pp observables near 2100 MeV is reviewed, and new data in this energy region are shown from SATURNE.

  2. Conversion of experimental half-life to effective electron neutrino mass in 0nubetabeta decay

    SciTech Connect

    Smolnikov, Anatoly; Grabmayr, Peter

    2010-02-15

    The Germanium Detector Array (GERDA) collaboration will be searching for neutrinoless double beta decay of {sup 76}Ge. As a result it will measure the half-life T{sub 1/2} of this rare process; or at least a new value for the lower limit for T{sub 1/2} will be derived. The sensitivity of the GERDA experiment on the effective electron neutrino mass depends on the theoretical value for the nuclear matrix element M and the kinematical phase space factor G.In this Brief Report we focus on existing difficulties in applying the dimensionless values of M calculated by various theoretical groups, which use different methods and parametrizations. The implicit radius dependencies in M and G are discussed. Resulting values of the neutrino mass are tabulated for various representative half-lives T{sub 1/2} representing the sensitivity of the various phases of the GERDA experiment.

  3. Measuring $\\theta_{13}$ via Muon Neutrino to Electron Neutrino Oscillations in the MINOS Experiment

    SciTech Connect

    Toner, Ruth B.

    2011-01-01

    One of the primary goals in neutrino physics at the present moment is to make a measurement of the neutrino oscillation parameter $\\theta_{13}$. This parameter, in addition to being unknown, could potentially allow for the introduction of CP violation into the lepton sector. The MINOS long-baseline neutrino oscillation experiment has the ability to make a measurement of this parameter, by looking for the oscillation of muon neutrinos to electron neutrinos between a Near and Far Detector over a distance of 735 km. This thesis discusses the development of an analysis framework to search for this oscillation mode. Two major improvements to pre-existing analysis techniques have been implemented by the author. First, a novel particle ID technique based on strip topology, known as the Library Event Matching (LEM) method, is optimized for use in MINOS. Second, a multiple bin likelihood method is developed to fit the data. These two improvements, when combined, increase MINOS' sensitivity to $\\sin^2(2\\theta_{13})$ by 27\\% over previous analyses. This thesis sees a small excess over background in the Far Detector. A Frequentist interpretation of the data rules out $\\theta_{13}=0$ at 91\\%. A Bayesian interpretation of the data is also presented, placing the most stringent upper boundary on the oscillation parameter to date, at $\\sin^2(2\\theta_{13})<0.09(0.015)$ for the Normal (Inverted) Hierarchy and $\\delta_{CP}=0$.

  4. Low-Energy Neutron Scattering from Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Horton, Christopher Adams

    Fast neutron inelastic scattering cross sections for the 44.9-keV level in ^{238} U and the 49.4-keV level in ^{232 }Th, and the elastic scattering cross sections of ^{209}Bi and ^{232}Th have been measured using the neutron time-of-flight technique, at an incident neutron energy of 127 keV at six scattering angles from 45 ^circ to 122.5^circ . Neutrons were produced by the ^7 Li(p,n)^7Be reaction. A detector using two photomultiplier tubes in fast coincidence was built for these low-energy measurements. The detector efficiency was determined by comparison with that of a ^{235}U fission chamber. Special attention was paid to determining the efficiency near the ^7Li(p,n)^7Be reaction threshold. The spectrum unfolding included the removal of tails on the peaks which were assumed to be exponential functions. The inelastic peaks were stripped from the elastic peaks by using the shape of the bismuth elastic peak as a standard. Corrections for neutron attenuation were computed analytically. Corrections for multiple scattering were determined using a Monte Carlo method. Results were normalized to the ^{238}U differential elastic scattering cross sections and angular distributions. The angular distributions and integrated cross sections are compared with the ENDF/B-VI evaluation cross sections and with results at similar energies from previous measurements. The use of iron neutron filters for measuring cross sections at low energies is also discussed.

  5. Elastic Hadron Scattering on Li Isotopes at Intermediate Energies

    SciTech Connect

    Zhusupov, M.A.; Imambekov, O.; Ibraeva, E.T.

    2005-01-01

    The elastic scattering of hadrons (protons, charged pions, and positively charged kaons) on {sup 6,7,8}Li nuclei is analyzed on the basis of Glauber-Sitenko diffraction theory. A few nuclear-wave-function versions found within two- and three-particle potential cluster models are used in the calculations. It is shown that the application of these wave functions in diffraction theory makes it possible to describe adequately the experimental differential cross sections and analyzing powers in hadron scattering at intermediate energies. In this study, particular attention is given to a comparison of the scattering of different particles on the same target nucleus, as well as to a comparison of scattering of particles of the same sort on different target nuclei.

  6. Causality, renormalizability and ultra-high energy gravitational scattering

    NASA Astrophysics Data System (ADS)

    Hollowood, Timothy J.; Shore, Graham M.

    2016-05-01

    The amplitude { A }(s,t) for ultra-high energy scattering can be found in the leading eikonal approximation by considering propagation in an Aichelburg–Sexl gravitational shockwave background. Loop corrections in the QFT describing the scattered particles are encoded for energies below the Planck scale in an effective action which in general exhibits causality violation and Shapiro time advances. In this paper, we use Penrose limit techniques to calculate the full energy dependence of the scattering phase shift {{{\\Theta }}}{{scat}}(\\hat{s}), where the single variable \\hat{s}={Gs}/{m}2{b}d-2 contains both the CM energy s and impact parameter b, for a range of scalar QFTs in d dimensions with different renormalizability properties. We evaluate the high-energy limit of {{{\\Theta }}}{{scat}}(\\hat{s}) and show in detail how causality is related to the existence of a well-defined UV completion. Similarities with graviton scattering and the corresponding resolution of causality violation in the effective action by string theory are briefly discussed.

  7. Inelastic x-ray scattering at modest energy resolution

    SciTech Connect

    Finkelstein, K.D.; Larson, B.C.

    1997-07-01

    We report results from the development of an inelastic scattering spectrometer designed to take advantage of high energy synchrotron radiation available at CHESS. The device allows a large increase of the effective scattering volume in the sample by permitting measurements to be made in an energy range up to 25 KeV. The highest useable energy appears limited by the efficiency of the analyzers under consideration. At 20 KeV a novel 4-bounce, sagittal focusing monochromator passes 10e11 photons/second with Darwin width limited energy resolution. In the scattering plane, the monochromator images the electron beam producing a small scattering source for the analyzing optics. Analyzer systems under study include a cooled mosaic crystal in para-focusing geometry, and an adjustable spherically bent silicon crystal respectively for parallel and point-by-point collection of the energy loss spectrum. This paper discusses the optical configurations presents results from our early measurements and suggests directions for improvements. {copyright} {ital 1997 American Institute of Physics.}

  8. Theoretical Study of Low Energy Scattering from Metal Nuclei.

    NASA Astrophysics Data System (ADS)

    Gomez, Bernadette; Hira, Ajit; Duran, Joe; Jaramillo, Danelle

    2015-04-01

    We continue our interest in the interactions between different nuclear species with a computational study of the scattering of the low-energy nuclei of H through F atoms (Z <= 9 ) from Silver, Palladium and other metals. Recent work has shown that neutron scattering can be used to record holographic images of materials. We have developed a FORTRAN computer program to compute stopping cross sections and scattering angles in Ag and other metals for the small nuclear projectiles, using Monte Carlo calculation. This code allows for different angles of incidence. Next, simulations were done in the energy interval from 50 to 210 keV. The computational results thus obtained are compared with relevant experimental data. The data are further analyzed to identify periodic trends in terms of the atomic number of the projectile. Such studies have potential applications in nuclear physics and in nuclear medicine.

  9. Scattering of high-energy magnons off a magnetic skyrmion

    NASA Astrophysics Data System (ADS)

    Schroeter, Sarah; Garst, Markus

    2015-10-01

    We discuss the scattering of high-energy magnons off a single magnetic skyrmion within the field-polarized ground state of a two-dimensional chiral magnet. For wavevectors larger than the inverse skyrmion radius, krs ≫ 1 the magnon scattering is dominated by an emerging magnetic field whose flux density is essentially determined by the topological charge density of the skyrmion texture. This leads to skew and rainbow scattering characterized by an asymmetric and oscillating differential cross section. We demonstrate that the transversal momentum transfer to the skyrmion is universal due to the quantization of the total emerging flux while the longitudinal momentum transfer is negligible in the high-energy limit. This results in a magnon-driven skyrmion motion approximately antiparallel to the incoming magnon current and a universal relation between current and skyrmion-velocity.

  10. Low energy neutron deuteron scattering to N3LO

    NASA Astrophysics Data System (ADS)

    Margaryan, Arman; Vanasse, Jared; Springer, Roxanne

    2015-10-01

    We calculate the next-to-next-to-next-to-leading order (N3LO) nd scattering amplitude in the framework of nonrelativistic pionless effective field theory (EFTπ/). This theory is only valid when the typical momentum exchange in the scattering is smaller then the mass of the pion. The power counting parameter for EFTπ/ is the ratio Q/Λπ /, where Q is the typical momentum exchange in the scattering and Λπ / is the EFTπ/ breakdown scale, Λπ / scattering at leading order requires summing an infinite set of diagrams. The first nonzero polarization-dependent observables occur at N2LO. At N3LO new 2-body forces appear, which introduce four new EFTπ/ coefficients. These coefficients are fixed by the 3PJ and 1P1 phase shifts of NN scattering. We find that these terms have an important impact. The results of this calculation at N3LO will be important for understanding spin polarization observables in nd scattering, in particular the longstanding Ay puzzle. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics, under Award Number DE-FG02-05ER41368.

  11. Neutron Radii from Low Energy Pion Scattering.

    NASA Astrophysics Data System (ADS)

    Gyles, William

    Recent electron scattering measurements and muonic atom studies have allowed precise determinations of the charge distributions of nuclei. Measurements of the neutron distributions, however, have not progressed to this degree of sophistication, largely because of the uncertainties in the hadron-nucleus interaction. Charge distribution measurements provide good tests of nuclear structure calculations, but measurements of neutron distributions will provide independent constraints on these calculations and the potentials used. In this experiment, (pi)('-) differential cross section ratios were measured on pairs of isotopes (('36)S,('32)S), (('34)S,('32)S) with 50 MeV pions and (('26)Mg,('24)Mg) with 45 MeV pions. Absolute differential cross sections were also measured for ('32)S and ('24)Mg. Magnetic spectro -meters were used to collect the data. The cross section ratios were compared to optical model calcula-tions in which the parameters of a Fermi function representing the neutron distribution of the larger isotope of each pair were varied. The rms radius difference between the two isotopes producing the best fit was found to be independent of the details of the optical potential used, as long as the potential produced a fit to the absolute cross sections. The neutron distribution of the larger isotope was also rep-resented as a Fermi function modified by a sum of spherical Bessel functions, the coefficients of which were allowed to vary. The results for the rms radius differences were consistent with the Fermi function fits, except for ('34)S-('32)S, where the results differed by a full standard deviation. The rms radius differences found for the sulfur isotopes agreed with the results of shell-model calculations by Hodgson (Str82,Hod83). The extracted rms radius difference of the magnesium isotopes was one standard deviation less than the shell-model prediction. The results for the Fermi function fits, Fourier Bessell fits and the single particle potential (SPP

  12. A study of muon neutrino to electron neutrino oscillations in the MINOS experiment

    SciTech Connect

    Yang, Tingjun

    2009-03-01

    The observation of neutrino oscillations (neutrino changing from one flavor to another) has provided compelling evidence that the neutrinos have non-zero masses and that leptons mix, which is not part of the original Standard Model of particle physics. The theoretical framework that describes neutrino oscillation involves two mass scales (Δmatm2 and Δmsol2), three mixing angles (θ12, θ23, and θ13) and one CP violating phase (δCP). Both mass scales and two of the mixing angles (θ12 and θ23) have been measured by many neutrino experiments. The mixing angle θ13, which is believed to be very small, remains unknown. The current best limit on θ13 comes from the CHOOZ experiment: θ13 < 11° at 90% C.L. at the atmospheric mass scale. δCP is also unknown today. MINOS, the Main Injector Neutrino Oscillation Search, is a long baseline neutrino experiment based at Fermi National Accelerator Laboratory. The experiment uses a muon neutrino beam, which is measured 1 km downstream from its origin in the Near Detector at Fermilab and then 735 km later in the Far Detector at the Soudan mine. By comparing these two measurements, MINOS can obtain parameters in the atmospheric sector of neutrino oscillations. MINOS has published results on the precise measurement of Δmatm2 and θ23 through the disappearance of muon neutrinos in the Far Detector and on a search for sterile neutrinos by looking for a deficit in the number of neutral current interactions seen in the Far Detector. MINOS also has the potential to improve the limit on the neutrino mixing angle θ13 or make the first measurement of its value by searching for an electron neutrino appearance signal in the Far Detector. This is the focus of the study presented in this thesis. We developed a neural network based algorithm to

  13. Energy dependence of pion inelastic scattering from sup 208 Pb

    SciTech Connect

    Oakley, D.S. Lewis and Clark College, Portland, Oregon ); Peterson, R.J. ); Seestrom, S.J.; Morris, C.L.; Plum, M.A. ); Zumbro, J.D. ); Williams, A.L.; Bryan, M.A.; McDonald, J.W.; Moore, C.F. )

    1991-11-01

    Differential cross sections were measured for pion elastic and inelastic scattering from {sup 208}Pb at {ital T}{sub {pi}}=120 and 250 MeV. Energy-dependent neutron- and proton-transition matrix elements for a range of excited states were extracted and tested for consistency, using several structure models.

  14. High energy scattering of Dirac particles on smooth potentials

    NASA Astrophysics Data System (ADS)

    Han, Nguyen Suan; Dung, Le Anh; Xuan, Nguyen Nhu; Thang, Vu Toan

    2016-08-01

    The derivation of the Glauber type representation for the high energy scattering amplitude of particles of spin 1/2 is given within the framework of the Dirac equation in the Foldy-Wouthuysen (FW) representation and two-component formalism. The differential cross-sections on the Yukawa and Gaussian potentials are also considered and discussed.

  15. Hadron dynamics in high-energy pion-nucleus scattering

    SciTech Connect

    Johnson, M.B.

    1992-12-31

    It is argued that pion-nucleus scattering at high energy (above 300 MeV) is likely to be easier to interpret than it has been at lower energies where the {Delta}{sub 33} resonance dominates. We establish this by examining the relative importance of various dynamic ingredients of scattering theory for high-energy pions and comparing different versions of the theory: a ``model-exact`` microscopic optical model and an eikonal approximation. For nuclei as heavy as Ca, the eikonal theory is an excellent approximation to the full theory for the angular distribution out to the position of the second minimum in the cross section. The prospects for using high-energy pions to examine modifications of nucleons and baryon resonances in nuclei, nuclear structure, exchange currents, short-range correlations, and to characterize pion propagation are discussed.

  16. Deep inelastic scattering at energies near the Coulomb barrier

    SciTech Connect

    Gehring, J.; Rehm, K.E.; Schiffer, J.P.

    1993-10-01

    A large yield for a process that appears to have many of the features of deep inelastic scattering has been observed at energies, near the Coulomb barrier in the systems {sup 112,124}Sn + {sup 58}Ni by Wolfs et al. In order to better understand the mechanisms by which energy dissipation takes place close to the barrier, we have extended the measurements of Wolfs to the system {sup 136}Xe + {sup 64}Ni. The use of inverse kinematics in the present measurements resulted in better mass and energy resolution due to reduced target effects and in more complete angular coverage. We have obtained angular distributions, mass distributions, and total cross sections for deep inelastic scattering at two energies near the barrier. The results on the closed neutron shell nucleus {sup 136}Xe complement those from the closed proton shell Sn nuclei.

  17. Low-energy electron scattering by formic acid

    SciTech Connect

    Trevisan, C. S.; Orel, A. E.; Rescigno, T. N.

    2006-10-15

    We report the results of fixed-nuclei complex Kohn variational calculations of elastic electron scattering by formic acid, HCOOH. Momentum transfer and angular differential cross sections for incident electron energies ranging from 0.1 to 15 eV are presented and compared to available experimental data. The low-energy behavior of the cross section is analyzed and found to be consistent with the existence of a virtual state.

  18. Resonance formation in low energy electron scattering from uracil

    NASA Astrophysics Data System (ADS)

    Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2014-05-01

    We present detailed ab initio results for resonance formation in low energy electron scattering from uracil obtained with the R-matrix method. We identify a larger number of resonances than any previous theoretical study. Most of these resonances have core-excited shape character and appear to be associated to the ring structure of the molecule. Their link to DEA spectra and to the resonances present in electron scattering from pyrimidine are discussed. Contribution to the Topical Issue "Electron and Positron Induced Processes", edited by Michael Brunger, Radu Campeanu, Masamitsu Hoshino, Oddur Ingólfsson, Paulo Limão-Vieira, Nigel Mason, Yasuyuki Nagashima and Hajime Tanuma.

  19. Low-energy elastic differential scattering of He/++/ by He.

    NASA Technical Reports Server (NTRS)

    Lam, S. K.; Doverspike, L. D.; Champion, R. L.

    1973-01-01

    Experimental results are developed for the relative elastic differential scattering of He(++) by He for collision energies in the range 4 equal to or less than E equal to or less than 75 eV. In the analysis of the data, semiclassical considerations are utilized, assuming that the dynamics of the scattering is governed solely by the B and E states of He2(++). It is shown that existing ab initio calculations for the intermolecular potentials predict differential cross sections which are not in particularly good agreement with the experimental data.

  20. Low-energy positron and electron scattering from nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Chiari, Luca; Zecca, Antonio; García, Gustavo; Blanco, Francisco; Brunger, M. J.

    2013-12-01

    Total cross section (TCS) measurements for positron scattering from nitrogen dioxide (NO2) are presented in the energy range 0.2-40 eV. The TCS, the elastic integral and differential cross sections, and the integral cross section accounting of all the inelastic processes (including positronium formation) have also been computed using the independent atom model with screening corrected additivity rule (IAM-SCAR) for incident energies from 1 to 1000 eV. A qualitative level of agreement is found between the present TCS experiment and theory at the common energies. As no previous measurements or calculations for positron-NO2 scattering exist in the literature, we also computed the TCS for electron collisions with NO2 employing the IAM-SCAR method. A comparison of those results to the present positron cross sections and the earlier electron-impact data and calculations is provided. To investigate the role that chemical substitution plays in positron scattering phenomena, we also compare the present positron-NO2 data with the TCSs measured at the University of Trento for positron scattering from N2O and CO2.

  1. Scattering Theory Calculations of Casimir Energies at High Curvature

    NASA Astrophysics Data System (ADS)

    Graham, Noah; Emig, Thorsten; Forrow, Aden; Jaffe, Robert; Kardar, Mehran; Maghrebi, Mohammad; Rahi, Jamal; Shpunt, Alex

    2013-03-01

    Scattering theory provides a powerful tool for capturing the response of an object to electromagnetic charge and field fluctuations. Techniques based on scattering theory have made possible a wide range of new calculations of Casimir energies. In this approach, the Casimir interaction energy for a collection of objects can be expressed in terms of the scattering T-matrices for each object individually, combined with universal translation matrices describing the objects' relative positions and orientations. These translation matrices are derived from an expansion of the free Green's function in an appropriate coordinate system, independent of the details of the objects themselves. This method proves particularly valuable for geometries involving high curvature, such as edges and tips. I will describe this approach in general terms and then give results from several problems to which it has been applied successfully. I will also discuss new developments in scattering theory that have been motivated by these problems. I would like to request that this abstract be part of a session on Casimir physics. Supported by the National Science Foundation, the US Department of Energy, the Defense Advanced Research Projects Agency, and the Deutsche Forschungsgemeinschaft

  2. Low-energy positron scattering by pyrimidine

    NASA Astrophysics Data System (ADS)

    Barbosa, Alessandra Souza; Pastega, Diego F.; Bettega, Márcio H. F.

    2015-12-01

    This work reports elastic integral and differential cross sections for positron collisions with pyrimidine, for energies up to 20 eV. The cross sections were computed with the Schwinger multichannel method in the static plus polarization approximation. We also employed the Born closure procedure to account for the long range potential due to the permanent dipole moment of the molecule. Our results are compared with the experimental total cross section of Zecca et al. [J. Phys. B 43, 215204 (2010)], the experimental grand-total, quasi-elastic integral and differential cross section of Palihawadana et al. [Phys. Rev. A 88, 12717 (2013)]. We also compare our results with theoretical integral and differential cross sections obtained by Sanz et al. [Phys. Rev. A 88, 62704 (2013)] with the R-matrix and the independent atom model with screening-corrected additivity rule methods, and with the results computed by Franz and Gianturco [Phys. Rev. A 88, 042711 (2013)] using model correlation-polarization potentials. The agreement between the theory and the experiment is encouraging.

  3. Low-energy positron scattering by pyrimidine

    SciTech Connect

    Barbosa, Alessandra Souza; Pastega, Diego F.; Bettega, Márcio H. F.

    2015-12-28

    This work reports elastic integral and differential cross sections for positron collisions with pyrimidine, for energies up to 20 eV. The cross sections were computed with the Schwinger multichannel method in the static plus polarization approximation. We also employed the Born closure procedure to account for the long range potential due to the permanent dipole moment of the molecule. Our results are compared with the experimental total cross section of Zecca et al. [J. Phys. B 43, 215204 (2010)], the experimental grand-total, quasi-elastic integral and differential cross section of Palihawadana et al. [Phys. Rev. A 88, 12717 (2013)]. We also compare our results with theoretical integral and differential cross sections obtained by Sanz et al. [Phys. Rev. A 88, 62704 (2013)] with the R-matrix and the independent atom model with screening-corrected additivity rule methods, and with the results computed by Franz and Gianturco [Phys. Rev. A 88, 042711 (2013)] using model correlation-polarization potentials. The agreement between the theory and the experiment is encouraging.

  4. About multiple scattering of high energy protons in crystal deflectors

    NASA Astrophysics Data System (ADS)

    Taratin, A. M.; Scandale, W.

    2015-07-01

    The process of multiple scattering of high energy protons in a silicon crystal at its amorphous orientation was studied by simulation of proton trajectories in the model of binary collisions and by a straight simulation of the sequences of proton collisions with atoms when their impact parameters are randomly and uniformly distributed on the symmetry cell for a given crystallography direction. The value of the RMS deflection of multiple scattering obtained by the simulation is in a good agreement with the experiment and more than 15% larger than it follows from the Moliere theory. The obtained RMS deflection used in the Gaussian approach of multiple scattering well describes dechanneling of protons in the frame of the planar potential model. Different number of proton collisions with atoms occurs along the same crystal length for different crystal orientations. However, the change of the collision number is compensated by the corresponding change of the mean square deflection in a single collision. Therefore, multiple scattering is the same for different crystal orientations. The generator of multiple scattering for amorphous crystal orientations was proposed.

  5. Nucleon-nucleon scattering contribution to the triton binding energy

    SciTech Connect

    Noyes, H.P.

    1983-04-01

    We conjectured in 1972 that much of the dynamics of a few nucleon systems could be computed from the on-shell nucleon-nucleon scatterings provided that a consistent few body theory using this input could be constructed. Such a Zero Range Scattering Theory has been shown to lead to unitary three and four particle scattering amplitudes provided only the two particle amplitudes have no singularities other than bound state poles when continued to negative energies, which restricts the theory to Castillejo-Dalitz-Dyson solutions of the Low equation. We extend the model by rewriting the off-shell amplitude which drives the Faddeev equations. This amplitude retains full off-shell unitarity and still leads to unitary on-shell three particle amplitudes. This amounts to keeping any unitary two-nucleon amplitude on-shell and restricting the analytic continuation to negative energies to the term which represents the correct continuation of the two particle total partial wave cross section; the meson exchange or potential contributions are eliminated in the unphysical region, thus excising the left-hand cut. Using this model in the zero range Faddeev equations for the three nucleon system our preliminary results show that the on-shell scatterings bind the triton with about 2.5 MeV and are insensitive to the details of the fit.

  6. Parity violation in low-energy neutron-deuteron scattering

    SciTech Connect

    Song, Young-Ho; Gudkov, Vladimir; Lazauskas, Rimantas

    2011-01-15

    Parity-violating effects for low-energy elastic neutron deuteron scattering are calculated for Desplanques, Donoghue, and Holstein (DDH) and effective field theory types of weak potentials in a distorted-wave Born approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The resulting relation between physical observables and low-energy constants can be used to fix low-energy constants from experiments. Potential model dependencies of parity-violating effects are discussed.

  7. Computational Study of Low Energy Nuclear Scattering from Metal Nuclei

    NASA Astrophysics Data System (ADS)

    Jaramillo, Danelle; Hira, Ajit; Pacheco, Jose; Salazar, Justin

    2014-03-01

    We continue our interest in the interactions between different nuclear species with a computational study of the scattering of the low-energy nuclei of H through F atoms (Z <= 9) from Palladium, Nickel and other metals. First, a FORTRAN computer program was developed to compute stopping cross sections and scattering angles in Pd and other metals for the small nuclear projectiles, using Monte Carlo calculation. This code allows for different angles of incidence. Next, simulations were done in the energy interval from 10 to 140 keV. The computational results thus obtained are compared with relevant experimental data. The data are further analyzed to identify periodic trends in terms of the atomic number of the projectile. Such studies have potential applications in nuclear physics and in nuclear medicine.

  8. Theory of high-energy electron scattering by composite targets

    SciTech Connect

    Coester, F.

    1988-01-01

    The emphasis of these expository lectures is on the role of relativistic invariance and the unity of the theory for medium and high energies. Sec. 2 introduces the kinematic notation and provides an elementary derivation of the general cross section. The relevant properties of the Poincare group and the transformation properties of current operators and target states are described in Sec 3. In Sec. 4 representations of target states with kinematic light-front symmetry are briefly discussed. The focus is on two applications. An impulse approximation of inclusive electron nucleus scattering at both medium and high energies. A parton model of the proton applied to deep inelastic scattering of polarized electrons by polarized protons. 19 refs.

  9. Elastic scattering of low-energy electrons from toluene

    NASA Astrophysics Data System (ADS)

    Sakaamini, Ahmad; Hargreaves, L. R.; Khakoo, M. A.; Pastega, D. F.; Bettega, M. H. F.

    2016-04-01

    Theoretical and normalized experimental differential, momentum transfer, and integral cross sections for vibrationally elastic scattering of low-energy electrons from toluene (C6H5C H3 ) are presented. The differential cross sections are measured at incident energies from 1 to 20 eV and scattering angles from 15° to 130°. The calculated cross sections are obtained using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Comparisons are made between the present theory and measurements with earlier available measurements. In general, the agreement between the theory and the experiment is very good. We also discuss the resonance spectra of toluene, where we find three π* shape resonances whose locations agree well with the experiment. In addition, we compare the cross sections of toluene and benzene, since the former can be considered as a benzene derivative by the substitution of a hydrogen in benzene by a C H3 group in toluene.

  10. Seismic energy transmission in an intensively scattering environment

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.

    1977-01-01

    In order to account for some special features of lunar seismograms, namely, the gradual build-up of the signal, the extremely prolonged tail, and the lack of apparent coherence among three orthogonal components of ground motion, a statistical approach is proposed for describing transmission of seismic energy through a medium in which strong scattering takes place. A seismic diffusion theory is presented for a medium with randomly distributed scatterers of a given size distribution. A solution of the resulting diffusion equation for an impulsive energy source gives a curve which fairly closely reproduces the envelope of typical lunar impact seismograms. Since the model is based on constant diffusivity, long-range transmission will require a combination of diffusion and wave propagation treatments for accurate description.

  11. Resonances in low-energy positron-alkali scattering

    NASA Technical Reports Server (NTRS)

    Horbatsch, M.; Ward, S. J.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    Close-coupling calculations were performed with up to five target states at energies in the excitation threshold region for positron scattering from Li, Na and K. Resonances were discovered in the L = 0, 1 and 2 channels in the vicinity of the atomic excitation thresholds. The widths of these resonances vary between 0.2 and 130 MeV. Evidence was found for the existence of positron-alkali bound states in all cases.

  12. Scattering of low-energy neutrinos on atomic shells

    NASA Astrophysics Data System (ADS)

    Babič, Andrej; Šimkovic, Fedor

    2015-10-01

    We present a derivation of the total cross section for inelastic scattering of low-energy solar neutrinos and reactor antineutrinos on bound electrons, resulting in a transition of the electron to an excited state. The atomic-shell structure of various chemical elements is treated in terms of a nonrelativistic approximation. We estimate the interaction rates for modern neutrino detectors, in particular the Borexino and GEMMA experiments. We establish that in these experiments the effect can be safely neglected, but it could be accessible to future large-volume neutrino detectors with low energy threshold.

  13. Scattering of low-energy neutrinos on atomic shells

    SciTech Connect

    Babič, Andrej; Šimkovic, Fedor

    2015-10-28

    We present a derivation of the total cross section for inelastic scattering of low-energy solar neutrinos and reactor antineutrinos on bound electrons, resulting in a transition of the electron to an excited state. The atomic-shell structure of various chemical elements is treated in terms of a nonrelativistic approximation. We estimate the interaction rates for modern neutrino detectors, in particular the Borexino and GEMMA experiments. We establish that in these experiments the effect can be safely neglected, but it could be accessible to future large-volume neutrino detectors with low energy threshold.

  14. Inverse scattering at fixed energy on asymptotically hyperbolic Liouville surfaces

    NASA Astrophysics Data System (ADS)

    Daudé, Thierry; Kamran, Niky; Nicoleau, Francois

    2015-12-01

    In this paper, we study an inverse scattering problem on Liouville surfaces having two asymptotically hyperbolic ends. The main property of Liouville surfaces consists of the complete separability of the Hamilton-Jacobi equations for the geodesic flow. An important related consequence is the fact that the stationary wave equation can be separated into a system of radial and angular ODEs. The full scattering matrix at fixed energy associated to a scalar wave equation on asymptotically hyperbolic Liouville surfaces can be thus simplified by considering its restrictions onto the generalized harmonics corresponding to the angular separated ODE. The resulting partial scattering matrices consists in a countable set of 2 × 2 matrices whose coefficients are the so called transmission and reflection coefficients. It is shown that the reflection coefficients are nothing but generalized Weyl-Titchmarsh (WT) functions for the radial ODE in which the generalized angular momentum is seen as the spectral parameter. Using the complex angular momentum method and recent results on 1D inverse problem from generalized WT functions, we show that the knowledge of the reflection operators at a fixed non-zero energy is enough to determine uniquely the metric of the asymptotically hyperbolic Liouville surface under consideration.

  15. Virtual Compton scattering off the nucleon at low energies

    SciTech Connect

    Scherer, S.; Korchin, A.Y.; Koch, J.H.

    1996-08-01

    We investigate the low-energy behavior of the four-point Green{close_quote}s function {Gamma}{sup {mu}{nu}} describing virtual Compton scattering off the nucleon. Using Lorentz invariance, gauge invariance, and crossing symmetry, we derive the leading terms of an expansion of the operator in the four-momenta {ital q} and {ital q}{sup {prime}} of the initial and final photon, respectively. The model-independent result is expressed in terms of the electromagnetic form factors of the free nucleon, i.e., on-shell information which one obtains from electron-nucleon scattering experiments. Model-dependent terms appear in the operator at {ital O}({ital q}{sub {alpha}}{ital q}{sub {beta}}{sup {prime}}), whereas the orders {ital O}({ital q}{sub {alpha}}{ital q}{sub {beta}}) and {ital O}({ital q}{sub {alpha}}{sup {prime}}{ital q}{sub {beta}}{sup {prime}}) are contained in the low-energy theorem for {Gamma}{sup {mu}{nu}}, i.e., no new parameters appear. We discuss the leading terms of the matrix element and comment on the use of on-shell equivalent electromagnetic vertices in the calculation of {open_quote}{open_quote}Born terms{close_quote}{close_quote} for virtual Compton scattering. {copyright} {ital 1996 The American Physical Society.}

  16. np elastic scattering analyzing power characteristics at intermediate energies

    SciTech Connect

    Abegg, R.; Ahmad, M.; Bandyopadhyay, D.; Birchall, J.; Cairns, E.B.; Chantziantoniou, K.; Coombes, G.H.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Gubler, H.P.; Healey, D.C.; Lapointe, C.; Lee, W.P.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Page, S.A.; Plattner, G.R.; Poffenberger, P.R.; Ramsay, W.D.; Rodning, N.L.; Roy, G.; Soukup, J.; Svenne, J.P.; Tkachuk, R.R.; van Oers, W.T.H.; Wait, G.D.; Watson, J.W.; Ye, Y.; Zhang, Y.P. University of Manitoba, Department of Physics, Winnipeg, Manitoba, Canada R3T 2N2 University of Alberta, Department of Physics, Edmonton, Alberta, Canada T6G 2N5 University of Basel, Institute of Physics, CH-4000 Basel, Switzerland Kent State University, Department of Physics, Kent, Ohio 44242)

    1989-11-01

    Recent measurements of charge symmetry breaking in the {ital np} system at 477 MeV, and of {ital A}{sub 00{ital nn}} for {ital np} elastic scattering at 220, 325, and 425 MeV also yield accurate analyzing power data. These data allow the energy dependence of the analyzing power zero-crossing angle and the slope of the analyzing power at the zero-crossing angle to be determined. The incident neutron energies span a region where the zero-crossing angle is strongly energy dependent ({ital E}{sub {ital n}}{lt}250 MeV) to where it is almost independent of energy ({ital E}{sub {ital n}}{gt}350 MeV). The results are compared to current phase-shift analysis predictions, recently published data, and the predictions of the Bonn and Paris potentials.

  17. Endpoint behavior of high-energy scattering cross sections

    SciTech Connect

    Chay, Junegone; Kim, Chul

    2010-11-01

    In high-energy processes near the endpoint, there emerge new contributions associated with spectator interactions. Away from the endpoint region, these new contributions are suppressed compared to the leading contribution, but the leading contribution becomes suppressed as we approach the endpoint and the new contributions become comparable. We present how the new contributions scale as we reach the endpoint and show that they are comparable to the suppressed leading contributions in deep inelastic scattering by employing a power-counting analysis. The hadronic tensor in deep inelastic scattering is shown to factorize including the spectator interactions, and it can be expressed in terms of the light cone distribution amplitudes of initial hadrons. We also consider the contribution of the spectator contributions in Drell-Yan processes. Here the spectator interactions are suppressed compared to double parton annihilation according to the power counting.

  18. A combined muon-neutrino and electron-neutrino oscillation search at MiniBooNE

    SciTech Connect

    Monroe, Jocelyn R.; /Columbia U.

    2006-07-01

    MiniBooNE seeks to corroborate or refute the unconfirmed oscillation result from the LSND experiment. If correct, the result implies that a new kind of massive neutrino, with no weak interactions, participates in neutrino oscillations. MiniBooNE searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations with the Fermi National Accelerator Laboratory 8 GeV beam line, which produces a {nu}{sub {mu}} beam with an average energy of {approx} 0.8 GeV and an intrinsic {nu}{sub e} content of 0.4%. The neutrino detector is a 6.1 m radius sphere filled with CH{sub 2}, viewed by 1540 photo-multiplier tubes, and located 541 m downstream from the source. This work focuses on the estimation of systematic errors associated with the neutrino flux and neutrino interaction cross section predictions, and in particular, on constraining these uncertainties using in-situ MiniBooNE {nu}{sub {mu}} charged current quasielastic (CCQE) scattering data. A data set with {approx} 100,000 events is identified, with 91% CCQE purity. This data set is used to measure several parameters of the CCQE cross section: the axial mass, the Fermi momentum, the binding energy, and the functional dependence of the axial form factor on four-momentum transfer squared. Constraints on the {nu}{sub {mu}} and {nu}{sub e} fluxes are derived using the {nu}{sub {mu}} CCQE data set. A Monte Carlo study of a combined {nu}{sub {mu}} disappearance and {nu}{sub e} appearance oscillation fit is presented, which improves the {nu}{sub {mu}} {yields} {nu}{sub e} oscillation sensitivity of MiniBooNE with respect to a {nu}{sub e} appearance-only fit by 1.2-1.5{sigma}, depending on the value of {Delta}m{sup 2}.

  19. Energy dissipation and scattering angle distribution analysis of the classical trajectory calculations of methane scattering from a Ni(111) surface

    NASA Astrophysics Data System (ADS)

    Milot, Robin; Kleyn, A. W.; Jansen, A. P. J.

    2001-08-01

    We present classical trajectory calculations of the rotational vibrational scattering of a nonrigid methane molecule from a Ni(111) surface. Energy dissipation and scattering angles have been studied as a function of the translational kinetic energy, the incidence angle, the (rotational) nozzle temperature, and the surface temperature. Scattering angles are somewhat toward the surface for the incidence angles of 30°, 45°, and 60° at a translational energy of 96 kJ/mol. Energy loss is primarily from the normal component of the translational energy. It is transferred for somewhat more than half to the surface and the rest is transferred mostly to rotational motion. The spread in the change of translational energy has a basis in the spread of the transfer to rotational energy, and can be enhanced by raising of the surface temperature through the transfer process to the surface motion.

  20. Inelastic pion scattering by /sup 13/C at low energies

    SciTech Connect

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in /sup 13/C at an incident energy of 65 MeV. The data include results from both ..pi../sup +/ and ..pi../sup -/ measurements. In addition, ..pi../sup -/ measurements were made at T/sub ..pi../ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2/sup +/ state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs.

  1. CT energy weighting in the presence of scatter and limited energy resolution

    SciTech Connect

    Schmidt, Taly Gilat

    2010-03-15

    Purpose: Energy-resolved CT has the potential to improve the contrast-to-noise ratio (CNR) through optimal weighting of photons detected in energy bins. In general, optimal weighting gives higher weight to the lower energy photons that contain the most contrast information. However, low-energy photons are generally most corrupted by scatter and spectrum tailing, an effect caused by the limited energy resolution of the detector. This article first quantifies the effects of spectrum tailing on energy-resolved data, which may also be beneficial for material decomposition applications. Subsequently, the combined effects of energy weighting, spectrum tailing, and scatter are investigated through simulations. Methods: The study first investigated the effects of spectrum tailing on the estimated attenuation coefficients of homogeneous slab objects. Next, the study compared the CNR and artifact performance of images simulated with varying levels of scatter and spectrum tailing effects, and reconstructed with energy integrating, photon-counting, and two optimal linear weighting methods: Projection-based and image-based weighting. Realistic detector energy-response functions were simulated based on a previously proposed model. The energy-response functions represent the probability that a photon incident on the detector at a particular energy will be detected at a different energy. Realistic scatter was simulated with Monte Carlo methods. Results: Spectrum tailing resulted in a negative shift in the estimated attenuation coefficient of slab objects compared to an ideal detector. The magnitude of the shift varied with material composition, increased with material thickness, and decreased with photon energy. Spectrum tailing caused cupping artifacts and CT number inaccuracies in images reconstructed with optimal energy weighting, and did not impact images reconstructed with photon counting weighting. Spectrum tailing did not significantly impact the CNR in reconstructed images

  2. Low-Energy Elastic Electron Scattering by Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Zatsarinny O.; Bartschat, K.; Tayal, S. S.

    2006-01-01

    The B-spline R-matrix method is employed to investigate the low-energy elastic electron scattering by atomic oxygen. Flexible non-orthogonal sets of radial functions are used to construct the target description and to represent the scattering functions. A detailed investigation regarding the dependence of the predicted partial and total cross sections on the scattering model and the accuracy of the target description is presented. The predicted angle-integrated elastic cross sections are in good agreement with experiment, whereas significant discrepancies are found in the angle-differential elastic cross sections near the forward direction. .The near-threshold results are found to strongly depend on the treatment of inner-core short-range correlation effects in the target description, as well as on a proper account of the target polarizability. A sharp increase in the elastic cross sections below 1 eV found in some earlier calculations is judged to be an artifact of an unbalanced description of correlation in the N-electron target structure and the (N+l)-electron-collision problems.

  3. SPECT Compton-scattering correction by analysis of energy spectra.

    PubMed

    Koral, K F; Wang, X Q; Rogers, W L; Clinthorne, N H; Wang, X H

    1988-02-01

    The hypothesis that energy spectra at individual spatial locations in single photon emission computed tomographic projection images can be analyzed to separate the Compton-scattered component from the unscattered component is tested indirectly. An axially symmetric phantom consisting of a cylinder with a sphere is imaged with either the cylinder or the sphere containing 99mTc. An iterative peak-erosion algorithm and a fitting algorithm are given and employed to analyze the acquired spectra. Adequate separation into an unscattered component and a Compton-scattered component is judged on the basis of filtered-backprojection reconstruction of corrected projections. In the reconstructions, attenuation correction is based on the known geometry and the total attenuation cross section for water. An independent test of the accuracy of separation is not made. For both algorithms, reconstructed slices for the cold-sphere, hot-surround phantom have the correct shape as confirmed by simulation results that take into account the measured dependence of system resolution on depth. For the inverse phantom, a hot sphere in a cold surround, quantitative results with the fitting algorithm are accurate but with a particular number of iterations of the erosion algorithm are less good. (A greater number of iterations would improve the 26% error with the algorithm, however.) These preliminary results encourage us to believe that a method for correcting for Compton-scattering in a wide variety of objects can be found, thus helping to achieve quantitative SPECT. PMID:3258023

  4. High-energy Picosecond Laser Pulse Recirculation for Compton Scattering

    SciTech Connect

    Jovanovic, I; Anderson, S G; Betts, S M; Brown, C; Gibson, D J; Hartemann, F V; Hernandez, J E; Johnson, M; McNabb, D P; Messerly, M; Pruet, J; Shverdin, M Y; Siders, C W; Tremaine, A M; Barty, C J

    2007-06-12

    Frequency upconversion of laser-generated photons by inverse Compton scattering for applications such as nuclear spectroscopy and gamma-gamma collider concepts on the future ILC would benefit from an increase of average source brightness. The primary obstacle to higher average brightness is the relatively small Thomson scattering cross section. It has been proposed that this limitation can be partially overcome by use of laser pulse recirculation. The traditional approach to laser recirculation entails resonant coupling of low-energy pulse train to a cavity through a partially reflective mirror. Here we present an alternative, passive approach that is akin to 'burst-mode' operation and does not require interferometric alignment accuracy. Injection of a short and energetic laser pulse is achieved by placing a thin frequency converter, such as a nonlinear optical crystal, into the cavity in the path of the incident laser pulse. This method leads to the increase of x-ray/gamma-ray energy proportional to the increase in photon energy in frequency conversion. Furthermore, frequency tunability can be achieved by utilizing parametric amplifier in place of the frequency converter.

  5. Elastic Scattering of Low-Energy Electrons byTetrahydrofuran

    SciTech Connect

    Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.

    2006-05-09

    We present the results of ab initio calculations for elasticelectron scattering by tetrahydrofuran (THF) using the complex Kohnvariational method. We carried out fixed-nuclei calculations at theequilibrium geometry of the target molecule for incident electronenergies up to 20 eV. The calculated momentum transfer cross sectionsclearly reveal the presence of broad shape resonance behavior in the 8-10eV energy range, in agreement with recent experiments. The calculateddifferential cross sections at 20 eV, which include the effects of thelong-range electron-dipole interaction, are alsofound to be in agreementwith the most recent experimental findings.

  6. Semiphenomenological method of analysis for intermediate-energy alpha-nucleus elastic scattering data

    SciTech Connect

    Ahmad, I.; Alvi, M.A.

    1983-12-01

    We propose a semiphenomenological method of analysis for intermediate energy ..cap alpha..-nucleus elastic scattering experiments and demonstrate its usefulness by analyzing available elastic ..cap alpha..-nucleus scattering data at 1.37 GeV.

  7. Interaction of Electron Neutrinos with {sup 56}Fe in the LSD for E{sub {nu}{sub e}} {<=} 50 MeV

    SciTech Connect

    Gaponov, Yu.V.; Ryazhskaya, O.G.; Semenov, S.V.

    2004-11-01

    The neutrino pulses detected by the LSD (Liquid Scintillator Detector) on February 23, 1987, are analyzed on the basis of a two-stage model of supernova explosion. The number of events due to the electron-neutrino interaction with {sup 56}Fe in the LSD is calculated. The obtained number of signals is in agreement with experimental data.

  8. Low-energy 6He scattering in a microscopic model

    NASA Astrophysics Data System (ADS)

    Descouvemont, P.

    2016-03-01

    A microscopic version of the continuum discretized coupled channel (CDCC) method is used to investigate 6He scattering on 27Al,58Ni,120Sn, and 208Pb at energies around the Coulomb barrier. The 6He nucleus is described by an antisymmetric 6-nucleon wave function, defined in the resonating group method. The 6He continuum is simulated by square-integrable positive-energy states. The model is based only on well-known nucleon-target potentials and therefore does not depend on any adjustable parameter. I show that experimental elastic cross sections are fairly well reproduced. The calculation suggests that breakup effects increase for high-mass targets. For a light system such as 6He+27Al , breakup effects are small, and a single-channel approximation provides fair results. This property is explained by a very simple model, based on the sharp cutoff approximation for the scattering matrix. I also investigate the 6He-target optical potentials, which confirm that breakup channels are more important when the mass increases. At large distances, polarization effects increase the Coulomb barrier and provide a long-tail absorption component in the imaginary part of the nucleus-nucleus interaction.

  9. Low-energy electron scattering by carbon tetrachloride

    NASA Astrophysics Data System (ADS)

    Moreira, Giseli M.; Souza Barbosa, Alessandra; Pastega, Diego F.; Bettega, Márcio H. F.

    2016-02-01

    In this work we report calculated integral and differential elastic cross sections for the scattering of low-energy electrons by CCl4. We employ the Schwinger multichannel method with pseudopotentials to compute the cross sections in the static-exchange and static-exchange plus polarization approximations for energies up to 15 eV. We report two shape resonances located at 0.75 eV and 8 eV belonging to the T 2 and E symmetries of the T d group respectively. We also look at the s-wave contribution to the integral cross section and find no evidence of the presence of a Ramsauer-Townsend minimum. We compare our calculated cross sections with available experimental and theoretical results and find that in general the agreement is good.

  10. Elastic proton-deuteron scattering at intermediate energies

    SciTech Connect

    Ramazani-Moghaddam-Arani, A.; Amir-Ahmadi, H. R.; Biegun, A.; Eslami-Kalantari, M.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Shende, S. V.; Bacher, A. D.; Bailey, C. D.; Stephenson, E. J.; Gasparic, I.; Kistryn, St.; Sworst, R.; Kozela, A.; Micherdzinska, A. M.; Stephan, E.

    2008-07-15

    Observables in elastic proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects. The present experimental database for this reaction is large, but contains a large discrepancy between data sets for the differential cross section taken at 135 MeV/nucleon by two experimental research groups. This article reviews the background of this problem and presents new data taken at Kernfysisch Versneller Instituute (KVI). Differential cross sections and analyzing powers for the {sup 2}H(p-vector,d)p and {sup 1}H(d-vector,d)p reactions at 135 MeV/nucleon and 65 MeV/nucleon, respectively, have been measured. The differential cross-section data differ significantly from previous measurements and consistently follow the energy dependence as expected from an interpolation of published data taken over a large range at intermediate energies.

  11. Search for W-prime boson decaying to electron-neutrino pairs in p anti-p collisions at s**(1/2) = 1.96-TeV

    SciTech Connect

    Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; /Taiwan, Inst. Phys. /Argonne /Barcelona, IFAE /Baylor U. /INFN, Bologna /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara /Cantabria Inst. of Phys.

    2006-11-01

    The authors present the results of a search for W{prime} boson decaying to electron-neutrino pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using a data sample corresponding to 205 pb{sup -1} of integrated luminosity collected by the CDF II detector at Fermilab. They observe no evidence for this decay mode and set limits on the production cross section times branching fraction, assuming the neutrinos from W{prime} boson decays to be light. If they assume the manifest left-right symmetric model, they exclude a W{prime} boson with mass less than 788 GeV/c{sup 2} at the 95% confidence level.

  12. Low-energy elastic electron scattering from furan

    SciTech Connect

    Khakoo, M. A.; Muse, J.; Ralphs, K.; Costa, R. F.; Bettega, M. H. F.; Lima, M. A. P.

    2010-06-15

    We report normalized experimental and theoretical differential cross sections for elastic electron scattering by C{sub 4}H{sub 4}O (furan) molecules from a collaborative project between several Brazilian theoretical groups and an experimental group at California State Fullerton, USA. The measurements are obtained by using the relative flow method with helium as the standard gas and a thin aperture target gas collimating source. The relative flow method is applied without the restriction imposed by the relative flow pressure condition on helium and the unknown gas. The experimental data were taken at incident electron energies of 1, 1.5, 1.73, 2, 2.7, 3, 5, 7, 10, 20, 30, and 50 eV and covered the angular range between 10 deg. and 130 deg. The measurements verify observed {pi}* shape resonances at 1.65{+-}0.05eV and 3.10{+-}0.05 eV scattering energies, in good agreement with the transmission electron data of Modelli and Burrow [J. Phys. Chem. A 108, 5721 (2004)]. Furthermore, the present results also indicated both resonances dominantly in the d-wave channel. The differential cross sections are integrated in the standard way to obtain integral elastic cross sections and momentum transfer cross sections. The calculations employed the Schwinger multichannel method with pseudopotentials and were performed in the static-exchange and in the static-exchange plus polarization approximations. The calculated integral and momentum transfer cross sections clearly revealed the presence of two shape resonances located at 1.95 and 3.56 eV and ascribed to the B{sub 1} and A{sub 2} symmetries of the C{sub 2v} point group, respectively, in very good agreement with the experimental findings. Overall agreement between theory and experiment regarding the differential, momentum transfer, and integral cross sections is very good, especially for energies below 10 eV.

  13. Low energy elastic electron scattering from CF3Br molecules.

    PubMed

    Hargreaves, L R; Brunton, J R; Maddern, T M; Brunger, M J

    2015-03-28

    CF3Br is a potentially valuable precursor molecule for generating beams of gas phase Br radicals suitable for electron collisions studies. However, the utility of CF3Br for this purpose depends critically on the availability of sound scattering cross sections to allow the contribution of the precursor to be isolated within the total scattering signal. To this end, here we present elastic differential cross section (DCS) measurements for CF3Br at incident energies between 15 and 50 eV. Comparison of these DCSs to those from the only other available experimental study [Sunohara et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1843 (2003)] and a Schwinger multichannel with pseudo potentials (SMCPPs) calculation [Bettega et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1263 (2003)] shows generally a very good accord. Integral elastic and momentum transfer cross sections, derived from our DCSs, are also found to be in quite good agreement with the SMCPP results. PMID:25833582

  14. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    SciTech Connect

    Bisplinghoff, J.; Daniel, R.; Diehl, O.; Engelhardt, H.; Ernst, J.; Eversheim, P.; Gro-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Jahn, R.; Jeske, M.; Lahr, U.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Rohdje, H.; Rosendaal, D.; Ro, U.; Scheid, H.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Trelle, H.; Wiedmann, W.; Ziegler, R.; Albers, D.; Bollmann, R.; Bueer, K.; Dohrmann, F.; Gasthuber, M.; Greiff, J.; Gro, A.; Igelbrink, M.; Langkau, R.; Lindlein, J.; Mueller, M.; Muenstermann, M.; Schirm, N.; Scobel, W.; Wellinghausen, A.; Woller, K.; Cloth, P.; Gebel, R.; Maier, R.; Prasuhn, D.; von Rossen, P.; Sterzenbach, G.

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta p{sub p} (energies T{sub p}) from 1100 to 3300MeV/c (500 to 2500MeV) in the angular range 35{degree}{le}{Theta}{sub c.m.}{le}90{degree} with a detector providing {Delta}{Theta}{sub c.m.}{approx}1.4{degree} resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH{sub 2} fiber target, taking particular care to monitor luminosity as a function of T{sub p}. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found. {copyright} {ital 1997} {ital The American Physical Society}

  15. Novel scatter compensation of list-mode PET data using spatial and energy dependent corrections

    PubMed Central

    Guérin, Bastien

    2011-01-01

    With the widespread use of PET crystals with greatly improved energy resolution (e.g., 11.5% with LYSO as compared to 20% with BGO) and of list-mode acquisitions, the use of the energy of individual events in scatter correction schemes becomes feasible. We propose a novel scatter approach that incorporates the energy of individual photons in the scatter correction and reconstruction of list-mode PET data in addition to the spatial information presently used in clinical scanners. First, we rewrite the Poisson likelihood function of list-mode PET data including the energy distributions of primary and scatter coincidences and show that this expression yields an MLEM reconstruction algorithm containing both energy and spatial dependent corrections. To estimate the spatial distribution of scatter coincidences we use the single scatter simulation (SSS). Next, we derive two new formulae which allow estimation of the 2D (coincidences) energy probability density functions (E-PDF) of primary and scatter coincidences from the 1D (photons) E-PDFs associated with each photon. We also describe an accurate and robust object-specific method for estimating these 1D E-PDFs based on a decomposition of the total energy spectra detected across the scanner into primary and scattered components. Finally, we show that the energy information can be used to accurately normalize the scatter sinogram to the data. We compared the performance of this novel scatter correction incorporating both the position and energy of detected coincidences to that of the traditional approach modeling only the spatial distribution of scatter coincidences in 3D Monte Carlo simulations of a medium cylindrical phantom and a large, non uniform NCAT phantom. Incorporating the energy information in the scatter correction decreased bias in the activity distribution estimation by ~20% and ~40% in the cold regions of the large NCAT phantom at energy resolutions 11.5 and 20% at 511 keV, respectively, compared to when

  16. Low-Energy Electron Scattering by Sugarcane Lignocellulosic Biomass Molecules

    NASA Astrophysics Data System (ADS)

    Oliveira, Eliane; Sanchez, Sergio; Bettega, Marcio; Lima, Marco; Varella, Marcio

    2012-06-01

    The use of second generation (SG) bioethanol instead of fossil fuels could be a good strategy to reduce greenhouse gas emissions. However, the efficient production of SG bioethanol has being a challenge to researchers around the world. The main barrier one must overcome is the pretreatment, a very important step in SG bioethanol aimed at breaking down the biomass and facilitates the extraction of sugars from the biomass. Plasma-based treatment, which can generate reactive species, could be an interesting possibility since involves low-cost atmospheric-pressure plasma. In order to offer theoretical support to this technique, the interaction of low-energy electrons from the plasma with biomass is investigated. This study was motived by several works developed by Sanche et al., in which they understood that DNA damage arises from dissociative electron attachment, a mechanism in which electrons are resonantly trapped by DNA subunits. We will present elastic cross sections for low-energy electron scattering by sugarcane biomass molecules, obtained with the Schwinger multichannel method. Our calculations indicate the formation of π* shape resonances in the lignin subunits, while a series of broad and overlapping σ* resonances are found in cellulose and hemicellulose subunits. The presence of π* and σ* resonances could give rise to direct and indirect dissociation pathways in biomass. Then, theoretical resonance energies can be useful to guide the plasma-based pretreatment to break down specific linkages of interest in biomass.

  17. Spectroscopy of strongly correlated systems: Resonant x-ray scattering without energy resolution in the scattered beam

    NASA Astrophysics Data System (ADS)

    Braicovich, L.; Tagliaferri, A.; Annese, E.; Ghiringhelli, G.; Dallera, C.; Fracassi, F.; Palenzona, A.; Brookes, N. B.

    2007-02-01

    The total emission of photons excited by x rays (90° between incident and detected photons) is measured vs the incident photon energy at the CeM4,5 edges in CeIn3 , CeSnIn2 , CeAl2 , CePd3 , and CeRh2 , and at the NiL2,3 edges in NiO. The results show the signature of a second-order process; these experiments must be interpreted as genuine resonant inelastic scattering (though without energy resolution of the emitted photons) and not as absorption spectroscopy measured by the total fluorescence yield. In Ce compounds, information on bulk hybridization can thus be obtained simply and with high sensitivity. The branching ratio between the different scattering channels is also measured. This approach opens innovative perspectives in resonant inelastic x-ray scattering.

  18. An ultra-efficient energy transfer beyond plasmonic light scattering

    SciTech Connect

    Fu, Sze-Ming; Zhong, Yan-Kai; Lin, Albert

    2014-11-14

    The energy transfer between nano-particles is of great importance for, solar cells, light-emitting diodes, nano-particle waveguides, and other photonic devices. This study shows through novel design and algorithm optimization, the energy transfer efficiency between plasmonic and dielectric nano-particles can be greatly improved. Using versatile designs including core-shell wrapping, supercells and dielectric mediated plasmonic scattering, 0.05 dB/μm attenuation can be achieved, which is 20-fold reduction over the baseline plasmonic nano-particle chain, and 8-fold reduction over the baseline dielectric nano-particle chain. In addition, it is also found that the dielectric nano-particle chains can actually be more efficient than the plasmonic ones, at their respective optimized geometry. The underlying physics is that although plasmonic nano-particles provide stronger coupling and field emission, the effect of plasmonic absorption loss is actually more dominant resulting in high attenuation. Finally, the group velocity for all design schemes proposed in this work is shown to be maintained above 0.4c, and it is found that the geometry optimization for transmission also boosts the group velocity.

  19. A measurement of hadron production cross sections for the simulation of accelerator neutrino beams and a search for muon-neutrino to electron-neutrino oscillations in the Δm2 about equals 1-eV2 region

    SciTech Connect

    Schmitz, David W.

    2008-01-01

    A measurement of hadron production cross-sections for the simulation of accelerator neutrino beams and a search for muon neutrino to electron neutrino oscillations in the Δm2 ~ 1 eV2} region. This dissertation presents measurements from two different high energy physics experiments with a very strong connection: the Hadron Production (HARP) experiment located at CERN in Geneva, Switzerland, and the Mini Booster Neutrino Experiment (Mini-BooNE) located at Fermilab in Batavia, Illinois.

  20. Determination of Rest Mass Energy of the Electron by a Compton Scattering Experiment

    ERIC Educational Resources Information Center

    Prasannakumar, S.; Krishnaveni, S.; Umesh, T. K.

    2012-01-01

    We report here a simple Compton scattering experiment which may be carried out in graduate and undergraduate laboratories to determine the rest mass energy of the electron. In the present experiment, we have measured the energies of the Compton scattered gamma rays with a NaI(Tl) gamma ray spectrometer coupled to a 1 K multichannel analyzer at…

  1. Electron scattering as a tool to study zero-point kinetic energies of atoms in molecules

    NASA Astrophysics Data System (ADS)

    Moreh, R.; Finkelstein, Y.; Vos, M.

    2015-07-01

    High resolution electron compton scattering (ECS) is being used to study the atomic momentum distributions and hence the zero-point kinetic energies (ZPKE) of the scattering atoms. Such studies have shown that the scattering is from a single atom of the scattering sample. For an electron beam with a well defined incident energy, the scattered electron energy at any angle from each atomic species is Doppler broadened. The broadening reflects the atomic momentum distribution contributed by both the internal and external motions of the molecular system. By measuring the Doppler broadening of the scattered electron lines it was possible to determine the kinetic energy of the scattering atom including that of its zero-point motion. Thus, the atomic kinetic energies in gases such as H2, D2, HD, CH4 and in H2O, D2O and NH3 were measured and compared with those calculated semi-empirically using the measured optical infra red (IR) and Raman frequencies of the internal vibrations of the molecules. In general, good agreement between the measured and calculated values was found. Electron scattering was also used to study the ratio of e-scattering intensities from the H- and O-atoms in water (H2O), where some anomalies were reported to exist.

  2. Low-energy electron scattering by cellulose and hemicellulose components.

    PubMed

    de Oliveira, Eliane M; da Costa, Romarly F; Sanchez, Sergio d'A; Natalense, Alexandra P P; Bettega, Márcio H F; Lima, Marco A P; Varella, Márcio T do N

    2013-02-01

    We report elastic integral, differential and momentum transfer cross sections for low-energy electron scattering by the cellulose components β-D-glucose and cellobiose (β(1 → 4) linked glucose dimer), and the hemicellulose component β-D-xylose. For comparison with the β forms, we also obtain results for the amylose subunits α-D-glucose and maltose (α(1 → 4) linked glucose dimer). The integral cross sections show double peaked broad structures between 8 eV and 20 eV similar to previously reported results for tetrahydrofuran and 2-deoxyribose, suggesting a general feature of molecules containing furanose and pyranose rings. These broad structures would reflect OH, CO and/or CC σ* resonances, where inspection of low-lying virtual orbitals suggests significant contribution from anion states. Though we do not examine dissociation pathways, these anion states could play a role in dissociative electron attachment mechanisms, in case they were coupled to the long-lived π* anions found in lignin subunits [de Oliveira et al., Phys. Rev. A, 2012, 86, 020701(R)]. Altogether, the resonance spectra of lignin, cellulose and hemicellulose components establish a physical-chemical basis for electron-induced biomass pretreatment that could be applied to biofuel production. PMID:23247550

  3. Quasielastic Scattering at MiniBooNE Energies

    SciTech Connect

    Alvarez-Ruso, L.; Buss, O.; Leitner, T.; Mosel, U.

    2009-11-25

    We present our description of neutrino induced charged current quasielastic scattering (CCQE) in nuclei at energies relevant for the MiniBooNE experiment. In our framework, the nucleons, with initial momentum distributions according to the Local Fermi Gas model, move in a density- and momentum-dependent mean field potential. The broadening of the outgoing nucleons due to nucleon-nucleon interactions is taken into account by spectral functions. Long range (RPA) correlations renormalizing the electroweak strength in the medium are also incorporated. The background from resonance excitation events that do not lead to pions in the final state is also predicted by propagating the outgoing hadrons with the Giessen semiclassical BUU model in coupled channels (GiBUU). We achieve a good description of the shape of the CCQE Q{sup 2} distribution extracted from data by MiniBooNE, thanks to the inclusion of RPA correlations, but underestimate the integrated cross section when the standard value of M{sub A} = 1 GeV is used. Possible reasons for this mismatch are discussed.

  4. Theoretical modeling for neutron elastic scattering angular distribution in the fast energy range

    SciTech Connect

    Kawano, Toshihiko

    2010-12-07

    One of the major issues of neutron scattering modeling in the fast energy range is the contribution of compound elastic and inelastic scattering to the total scattering process. The compound component may become large at very low energies where the angular distribution becomes 90-degree symmetric in the center-of-mass system. Together with the shape elastic component, the elastic scattering gives slightly forward-peaked angular distributions in the fast energy range. This anisotropic angular distribution gives high sensitivities to many important nuclear reactor characteristics, such as criticality and neutron shielding. In this talk we describe how the anisotropic angular distributions are calculated within the statistical model framework, including the case where strongly coupled channels exist, by combining the coupled-channels theory with the Hauser-Feshbach model. This unique capability extension will have significant advantages in understanding the neutron scattering process for deformed nuclei, like uranium or plutonium, on which advanced nuclear energy applications center.

  5. Energy and charge transfer for Na+ ions scattered from a Ag(001) surface

    NASA Astrophysics Data System (ADS)

    Ray, M. P.; Lake, R. E.; Marston, J. B.; Sosolik, C. E.

    2015-05-01

    We present energy- and charge-resolved measurements of low and hyperthermal energy Na+ ions scattered from a Ag(001) surface. With the primary ion beam oriented along the [110] crystal direction, distinct peaks in the energy distributions of the scattered beam flux that correspond to single or multiple collisions with target atoms are observed. A classical trajectory simulation reveals that these collisions can occur either at the surface or within the [110] channels, depending on incident beam energy. Within the simulation we probe the role of finite temperature and thermally displaced atoms on specific scattering events and show that contributions to the scattered distributions from single and double collisions dominate within the [110] channels. We also report velocity dependent measurements of the neutral/ion ratio of the scattered beam flux. A deviation between the data and simulated charge transfer results is observed for Na trajectories which penetrate the surface.

  6. Energy and angular distributions of hyperthermal-energy Li{sup +} scattered from Cu(001)

    SciTech Connect

    Behringer, E.R.; McLean, J.G.; Cooper, B.H.

    1996-03-01

    We have measured the in-plane energy and angular distributions of scattered Li{sup +} ions that result when Li{sup +} ion beams with incident energies {ital E}{sub {ital i}}=100 and 400 eV impinge on Cu(001) with an incident angle {theta}{sub {ital i}}=65{degree} and along the {l_angle}100{r_angle} azimuth. By comparing the energy and angular distributions with those generated by classical trajectory simulations, we extract information about the ion-surface interaction potential. A model ion-surface potential consisting of a sum of Hartree-Fock pair potentials and an attractive term produces good agreement with the measured distributions at both incident energies, while the universal potential of Ziegler, Biersack, and Littmarck does so only for {ital E}{sub {ital i}} = 400 eV. Analysis of the simulated distributions enables us to correlate different types of scattering events with features of the measured distributions (e.g., rainbows) and so obtain a detailed understanding of the scattering of Li{sup +}, which is more complex than has been previously observed for heavier alkali ions (e.g., Na{sup +} and K{sup +}). We find that the energy loss of the Li{sup +} ions can be mostly accounted for by momentum transfer to the surface atoms and that inelastic losses are small but significant for this system at these incident energies. We also find that the thermal vibrations of the surface atoms have dramatic effects on the simulated energy and angular distributions. {copyright} {ital 1996 The American Physical Society.}

  7. Study of Low Energy Electron Inelastic Scattering Mechanisms Using Spin Sensitive Techniques

    NASA Astrophysics Data System (ADS)

    Hsu, Hongbing

    1995-01-01

    Spin sensitive electron spectroscopies were used to study low energy electron inelastic scattering from metal surfaces and thin films. In these experiments, a beam of spin polarized electrons from a GaAs source is directed on the sample surface, and the spin polarization and intensity are measured as a function of energy loss and scattering angle by a Mott electron polarimeter coupled with a concentric hemispherical energy analyzer. Systematic studies of the angular dependence of inelastically scattered electrons were conducted on a Cu(100) surface, and Mo/Cu(100), non-magnetized Fe/Cu(100), and Co/Cu(100) films. The polarization and intensity of scattered electrons were measured as function of energy loss and scattering angle. Further studies were also conducted on Ag(100) surface and amorphous Cu/Ag(100) films. From the experimental results, the angular distributions of dipole and impact scattered electrons can be determined individually and both are found to peak in the specular scattering direction. Preliminary studies were conducted on magnetized Co/Cu(100) films. The spin dependent scattering intensity asymmetry was measured, with a clearly observable peak at energy loss of ~1 eV, which coincides with the band splitting. The polarizations of secondary electrons produced by an unpolarized primary beam were also measured. The polarizations can be related to the band polarization of magnetized cobalt films.

  8. Neutrino mass hierarchy and electron neutrino oscillation parameters with one hundred thousand reactor events

    NASA Astrophysics Data System (ADS)

    Capozzi, F.; Lisi, E.; Marrone, A.

    2014-01-01

    Proposed medium-baseline reactor neutrino experiments offer unprecedented opportunities to probe, at the same time, the mass-mixing parameters which govern νe oscillations both at long wavelength (δm2 and θ12) and at short wavelength (Δm2 and θ13), as well as their tiny interference effects related to the mass hierarchy (i.e., the relative sign of Δm2 and δm2). In order to take full advantage of these opportunities, precision calculations and refined statistical analyses of event spectra are required. In such a context, we revisit several input ingredients, including nucleon recoil in inverse beta decay and its impact on energy reconstruction and resolution, hierarchy and matter effects in the oscillation probability, spread of reactor distances, irreducible backgrounds from geoneutrinos and from far reactors, and degeneracies between energy scale and spectrum shape uncertainties. We also introduce a continuous parameter α, which interpolates smoothly between normal hierarchy (α =+1) and inverted hierarchy (α =-1). The determination of the hierarchy is then transformed from a test of hypothesis to a parameter estimation, with a sensitivity given by the distance of the true case (either α=+1 or α =-1) from the "undecidable" case (α=0). Numerical experiments are performed for the specific setup envisaged for the JUNO project, assuming a realistic sample of O(105) reactor events. We find a typical sensitivity of ˜2σ to the hierarchy in JUNO, which, however, can be challenged by energy scale and spectrum shape systematics, whose possible conspiracy effects are investigated. The prospective accuracy reachable for the other mass-mixing parameters is also discussed.

  9. Measurement of high energy resolution inelastic proton scattering at and close to zero degrees

    NASA Astrophysics Data System (ADS)

    Tamii, A.; Fujita, Y.; Matsubara, H.; Adachi, T.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, K.; Hashimoto, H.; Hatanaka, K.; Itahashi, T.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Ninomiya, S.; Perez-Cerdan, A. B.; Popescu, L.; Rubio, B.; Saito, T.; Sakaguchi, H.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Shimizu, Y.; Smit, F. D.; Tameshige, Y.; Yosoi, M.; Zenhiro, J.

    2009-07-01

    Measurements of inelastic proton scattering with high energy resolution at forward scattering angles including 0∘ are described. High-resolution halo-free beams were accelerated by the cyclotron complex at the Research Center for Nuclear Physics. Instrumental background events were minimized using the high-quality beam. The remaining instrumental background events were eliminated by applying a background subtraction method. As a result, clean spectra were obtained even for a heavy target nucleus such as Pb208. A high energy resolution of 20 keV (FWHM) and a scattering angle resolution of ±0.6∘ were achieved at an incident proton energy of 295 MeV.

  10. Complete calculation of electroweak corrections for polarized Møller scattering at high energies

    NASA Astrophysics Data System (ADS)

    Zykunov, V. A.

    2009-09-01

    A complete calculation of electroweak radiative corrections to observables of polarized Møller scattering at high energies was performed. This calculation took explicitly into account contributions caused by hard bremsstrahlung. A FORTRAN code that permitted including radiative corrections to high-energy Møller scattering under arbitrary electron-detection conditions was written. It was shown that the electroweak corrections caused by hard bremsstrahlung were rather strongly dependent on the choice of experimental cuts and changed substantially the polarization asymmetry in the region of high energies and over a broad interval of scattering angles.

  11. Low energy positron interactions with uracil—Total scattering, positronium formation, and differential elastic scattering cross sections

    SciTech Connect

    Anderson, E. K.; Boadle, R. A.; Machacek, J. R.; Makochekanwa, C.; Sullivan, J. P.; Chiari, L.; Buckman, S. J.; Brunger, M. J.; Garcia, G.; Blanco, F.; Ingolfsson, O.

    2014-07-21

    Measurements of the grand total and total positronium formation cross sections for positron scattering from uracil have been performed for energies between 1 and 180 eV, using a trap-based beam apparatus. Angular, quasi-elastic differential cross section measurements at 1, 3, 5, 10, and 20 eV are also presented and discussed. These measurements are compared to existing experimental results and theoretical calculations, including our own calculations using a variant of the independent atom approach.

  12. Friction-induced energy-loss rainbows in atom surface scattering.

    PubMed

    Moix, Jeremy M; Pollak, Eli; Miret-Artés, Salvador

    2010-03-19

    The rainbow is due to extrema of the angular deflection function of light impinging on water drops. Generically, extrema of suitably defined deflection functions lead to rainbows. These include angular and rotational rainbows in surface scattering and more. Here we introduce the concept of an "energy-loss deflection function" for scattering of particles from a periodic surface whose extrema lead to a new form-the "energy-loss rainbow" which appears as multiple maxima in the final energy distribution of the scattered particle. Energy-loss rainbows are caused by frictional phonon effects which induce structure in the energy-loss distribution instead of "washing it out." We provide evidence that they have been observed in Ne scattering on self-assembled monolayers. PMID:20366489

  13. Scatter correction method with primary modulator for dual energy digital radiography: a preliminary study

    NASA Astrophysics Data System (ADS)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Jeon, Pil-Hyun; Kim, Hee-Joung

    2014-03-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, resulting in the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement and non-measurement-based methods have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate primary radiation. Cylindrical phantoms of variable size were used to quantify imaging performance. For scatter estimation, we used Discrete Fourier Transform filtering. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without correction. In the subtraction study, the average CNR with correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of scatter correction and the improvement of image quality using a primary modulator and showed the feasibility of

  14. Predicting reaction observables from back-scattering measurements in low-energy heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Diaz-Torres, A.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Gomes, P. R. S.; Lenske, H.

    2016-01-01

    A simplified, reliable and useful method, based on reaction theory, for calculating a number of integrated and differential cross sections in low-energy heavy-ion collisions is presented. Simplified formulae provide predictions of reaction, capture and elastic-scattering differential cross sections, using experimental information about elastic and quasi-elastic back-scattering excitation functions.

  15. Low energy scattering phase shifts for meson-baryon systems

    NASA Astrophysics Data System (ADS)

    Detmold, William; Nicholson, Amy N.

    2016-06-01

    In this work, we calculate meson-baryon scattering phase shifts in four channels using lattice QCD methods. From a set of calculations at four volumes, corresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of mπ˜390 MeV , we determine the scattering lengths and effective ranges for these systems at the corresponding quark masses. We also perform the calculation at a lighter quark mass, mπ˜230 MeV , on the largest volume. Using these determinations, along with those in previous work, we perform a chiral extrapolation of the scattering lengths to the physical point after correcting for the effective range contributions using the multivolume calculations performed at mπ˜390 MeV .

  16. A Measurement of Electron Neutrino Appearance in the MINOS Experiment After Four Years of Data

    SciTech Connect

    Cavanaugh, Steven

    2010-05-01

    This work attempts to measure or set a limit on sin2(2θ13), the parameter which describes vμ → ve oscillations. The MINOS detectors at Fermilab are used to perform a search for the oscillations utilizing a beam of vμ neutrinos created in the NuMI beamline by the collisions of 120 GeV protons with a carbon target. These collisions create π± and K± which are focused with magnetic horns, are allowed to decay, and result in a beam of vμ in the energy range of 1 to 30 GeV. Two functionally identical steel-scintillator calorimetric detectors are utilized to measure the interactions of the generated neutrinos. A detector close to the NuMI beam, located 104 m underground and 1040 m from the target, is used to measure the properties of the neutrino beam, including the flux, composition, and energy spectrum. This information is used in part to generate a predicted spectrum of neutrinos in absence of vμ → ve oscillations in the detector located far from the target, at a distance of 705 m underground and 735.5 km from the target. An excess of predicted ve charged current events in this far detector will be interpreted as vμ → ve oscillations, and a measurement of sin2(2θ13) will be made using a Feldman-Cousins analysis. The measurement of vμ → ve requires the separation of ve candidates from background events. New reconstruction software was developed with a focus on identifying ve candidate events in order to reduce systematic errors. The event parameters measured by this software were used as an input to an artificial neutral network event discriminator. The details of this reconstruction software and the other steps of the analysis necessary to making the measurement will be discussed. This work builds on a previous measurement made with this

  17. Parton-parton elastic scattering and rapidity gaps at SSC and LHC energies

    SciTech Connect

    Duca, V.D.

    1993-08-01

    The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.

  18. Parton-parton elastic scattering and rapidity gaps at Tevatron energies

    SciTech Connect

    Del Duca, V.; Tang, Wai-Keung

    1993-08-01

    The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at Tevatron energies.

  19. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    SciTech Connect

    Braicovich, L. Minola, M.; Dellea, G.; Ghiringhelli, G.; Le Tacon, M.; Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B.; Supruangnet, R.

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  20. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering.

    PubMed

    Braicovich, L; Minola, M; Dellea, G; Le Tacon, M; Moretti Sala, M; Morawe, C; Peffen, J-Ch; Supruangnet, R; Yakhou, F; Ghiringhelli, G; Brookes, N B

    2014-11-01

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B4C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L3 edge on a high-Tc superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%. PMID:25430146

  1. Review of the inverse scattering problem at fixed energy in quantum mechanics

    NASA Technical Reports Server (NTRS)

    Sabatier, P. C.

    1972-01-01

    Methods of solution of the inverse scattering problem at fixed energy in quantum mechanics are presented. Scattering experiments of a beam of particles at a nonrelativisitic energy by a target made up of particles are analyzed. The Schroedinger equation is used to develop the quantum mechanical description of the system and one of several functions depending on the relative distance of the particles. The inverse problem is the construction of the potentials from experimental measurements.

  2. Gravitational scattering in the ADD model at high and low energies

    NASA Astrophysics Data System (ADS)

    Gustafson, G.; Sjödahl, M.

    2008-01-01

    Gravitational scattering in the ADD model is considered at both sub- and transplanckian energies using a common formalism. By keeping a physical cut-off in the KK tower associated with virtual KK exchange, such as the cut-off implied by a finite brane width, troublesome divergences are removed from the calculations in both energy ranges. The scattering behavior depends on three different energy scales: the fundamental Planck mass, the collision energy and the inverse brane width. The result for energies low compared to the effective cut-off (inverse brane width) is a contact-like interaction. At high energies the gravitational scattering associated with the extra dimensional version of Newton’s law is recovered.

  3. An energy-subtraction Compton scatter camera design for in vivo medical imaging of radiopharmaceuticals

    SciTech Connect

    Rohe, R.C.; Valentine, J.D.

    1996-12-01

    A Compton scatter camera (CSC) design is proposed for imaging radioisotopes used as biotracers. A clinical version may increase sensitivity by a factor of over 100, while maintaining or improving spatial resolution, as compared with existing Anger cameras that use lead collimators. This novel approach is based on using energy subtraction ({Delta}E = E{sub 0} {minus} E{sub SC}, where E{sub 0}, {Delta}E, and E{sub SC} are the energy of the emitted gamma ray, the energy deposited by the initial Compton scatter, and the energy of the Compton scattered photon) to determine the amount of energy deposited in the primary system. The energy subtraction approach allows the requirement of high energy resolution to be placed on a secondary detector system instead of the primary detector system. Requiring primary system high energy resolution has significantly limited previous CSC designs for medical imaging applications. Furthermore, this approach is dependent on optimizing the camera design for data acquisition of gamma rays that undergo only one Compton scatter in a low-Z primary detector system followed by a total absorption of the Compton scattered photon in a high-Z secondary detector system. The proposed approach allows for a more compact primary detector system, a more simplified pulse processing interface, and a much less complicated detector cooling scheme as compared with previous CSC designs. Analytical calculations and Monte Carlo simulation results for some specific detector materials and geometries are presented.

  4. Elastic electron scattering in krypton in the energy range from 5 to 10 eV

    SciTech Connect

    Linert, Ireneusz; Mielewska, Brygida; Zubek, Mariusz; King, George C.

    2010-01-15

    Differential cross sections for elastic electron scattering in krypton have been measured at the energies of 5,7.5, and 10 eV over the scattering angle range from 30 deg. to 180 deg. The measurements for backward scattering employed the magnetic angle-changing technique. These differential cross sections have been integrated to yield the elastic integral and momentum transfer cross sections at the above energies. These new results are compared with the most recent measurements and calculations of the respective cross sections in krypton. The dependence of the differential cross sections on atomic polarizability of the heavier rare gas atoms argon, krypton, and xenon has also been investigated over the electron energy range 5-30 eV and for forward, backward, and intermediate scattering angles.

  5. cap alpha. /sup 4/He elastic scattering at high energies

    SciTech Connect

    Usmani, A.A.; Ahmad, I.; Usmani, Q.N.

    1989-03-01

    Differential cross sections for ..cap alpha.. /sup 4/He elastic scattering have been calculated at incident ..cap alpha..-particle momenta of 4.32, 5.07, and 7.0 GeV/c within the framework of Glauber multiple scattering theory. The full Glauber amplitude has been calculated using the Monte Carlo method for evaluating multidimensional integrals. We found that, in general, the more realistic double-Gaussian model for the density brings theory closer to experiment as compared to the generally used single-Gaussian model in some momentum transfer regions. Our results with the double-Gaussian model and an acceptable set of NN parameters are in fairly good agreement with the experimental data at 4.32 and 5.07 GeV/c.

  6. Comprehensive study of the surface peak in charge-integrated low-energy ion scattering spectra

    SciTech Connect

    Draxler, M.; Gruber, R.; Bauer, P.; Beikler, R.; Taglauer, E.; Schmid, K.; Ermolov, S. N.

    2003-08-01

    Low-energy ion scattering is very surface sensitive if scattered ions are analyzed. By time-of-flight (TOF) techniques, the neutral and the charge-integrated spectra (ions plus neutrals) are obtained, which yield information about deeper layers. It is well known that charge integrated spectra may exhibit a surface peak which is more pronounced for heavier projectiles, e.g., Ne ions. Aiming at a more profound physical understanding of this surface peak, we performed TOF experiments and computer simulations for H, He, and Ne projectiles scattered from a polycrystalline copper target. Measurements were done in the range of 1-9 keV for a scattering angle of 129 degree sign under UHV conditions. The simulations were performed using the MARLOWE code for the given experimental parameters and a polycrystalline target. In the experiments, a pronounced surface peak was observed at low energies, which fades away at higher energies. This peak is quantitatively reproduced by the simulation. Several atomic layers may contribute to the surface peak, depending on the energy. Analyzing the contributions of the individual outermost atomic layers, one finds that the binary collisions of the projectiles with atoms in the first and the second layer yield a narrow energy distribution, while the contribution from the deeper layers is dominated by multiple scattering and therefore exhibits a very broad energy spectrum. It is shown that the appearance of a more or less pronounced surface peak is due to the relative contributions of single scattering and multiple scattering and thus depends on the projectile energy and mass.

  7. Scatter correction using a primary modulator for dual energy digital radiography: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Kim, Hee-Joung

    2014-08-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, making up the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement- and non-measurement-based methods, have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate the primary radiation. Cylindrical phantoms of variable size were used to quantify the imaging performance. For scatter estimates, we used discrete Fourier transform filtering, e.g., a Gaussian low-high pass filter with a cut-off frequency. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without scatter correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without the correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without the correction. In the subtraction study, the average CNR with the correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of the scatter correction and the

  8. Energy dependence of the mean free path of excess hot electrons in solid xenon in the elastic scattering region

    SciTech Connect

    Plenkiewicz, B.; Plenkiewicz, P.; Jay-Gerin, J.

    1986-04-15

    It has been found recently from the analysis of low-energy electron-transmission experiments that the scattering mean free path lambda of excess hot electrons in solid xenon films oscillates with energy. We show in this paper that in these experiments lambda is predominantly controlled by the combined effect of both acoustical-phonon scattering and scattering by neutral point defects, and that its energy dependence is entirely caused by the changes in electron effective mass with energy.

  9. Low-energy Scattering of Positronium by Atoms

    NASA Technical Reports Server (NTRS)

    Ray, Hasi

    2007-01-01

    The survey reports theoretical studies involving positronium (Ps) - atom scattering. Investigations carried out in last few decades have been briefly reviewed in this article. A brief description of close-coupling approximation (CCA), the first-Born approximation (FBA) and the Born-Oppenheimer approximation (BOA) for Ps-Atom systems are made. The CCA codes of Ray et a1 [1-6] are reinvestigated using very fine mesh-points to search for resonances. The article advocates the need for an extended basis set & a systematic study using CCAs.

  10. Results on neutrino-electron elastic scattering at AGS energies

    SciTech Connect

    Lanou, R.E.

    1984-02-26

    In an experiment designed to study elastic scattering of nu/sub ..mu../ (and anti nu/sub ..mu../) from electrons and protons via the weak neutral current, we have recently completed several extensive data taking runs. Results for the cross section of nu/sub ..mu../ + e/sup -/ ..-->.. nu/sub ..mu../ + e/sup -/ are presented based upon the first third of the available sample. Preliminary analysis of anti nu/sub ..mu../ + e/sup -/ ..-->.. anti nu/sub ..mu../ + e/sup -/ is in progress and evidence for the signal is presented.

  11. Patterns of high energy massive string scatterings in the Regge regime

    NASA Astrophysics Data System (ADS)

    Ko, Sheng-Lan; Lee, Jen-Chi; Yang, Yi

    2009-06-01

    We calculate high energy massive string scattering amplitudes of open bosonic string in the Regge regime (RR). We found that the number of high energy amplitudes for each fixed mass level in the RR is much more numerous than that of Gross regime (GR) calculated previously. Moreover, we discover that the leading order amplitudes in the RR can be expressed in terms of the Kummer function of the second kind. In particular, based on a summation algorithm for Stirling number identities developed recently, we discover that the ratios calculated previously among scattering amplitudes in the GR can be extracted from this Kummer function in the RR. We conjecture and give evidences that the existence of these GR ratios in the RR persists to subleading orders in the Regge expansion of all string scattering amplitudes. Finally, we demonstrate the universal power-law behavior for all massive string scattering amplitudes in the RR.

  12. Two-photon fusion in high-energy electron-nucleus scattering

    SciTech Connect

    Faeldt, Goeran

    2011-04-15

    Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering are now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus to create the meson. The process takes place in the small-angle Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

  13. Crystal effects in the neutralization of He+ ions in the low energy ion scattering regime.

    PubMed

    Primetzhofer, D; Markin, S N; Juaristi, J I; Taglauer, E; Bauer, P

    2008-05-30

    Investigating possible crystal effects in ion scattering from elemental surfaces, measurements of the positive ion fraction P+ are reported for He+ ions scattered from single and polycrystalline Cu surfaces. In the Auger neutralization regime, the ion yield is determined by scattering from the outermost atomic layer. For Cu(110) P+ exceeds that for polycrystalline Cu by up to a factor of 2.5, thus exhibiting a strong crystal effect. It is much less pronounced at higher energies, i.e., in the reionization regime. However, there a completely different angular dependence of the ion yield is observed for poly- and single crystals, due to massive subsurface contributions in nonchanneling directions. PMID:18518602

  14. Energy-dependent effects of scattering atmospheres on X-ray pulsar pulse profiles

    NASA Technical Reports Server (NTRS)

    Sturner, Steven J.; Dermer, Charles D.

    1994-01-01

    We propose that radiation-supported scattering atmospheres near accreting X-ray pulsars (XRPs) can explain energy-dependent features observed in the pulse profiles of 4U 1626-67, 4U 1538-52, 4U 1907+09 and Vela X-1. These atmospheres provide a physical model for the phenomenological annular emitting regions employed by Leahy to fit X-ray pulsar pulse profiles. We examine the effects of the scattering atmospheres under the assumptions that stable, optically thick atmospheres exist in a region where the optically thin resonant radiation force exceeds the force of gravity on ionized hydrogen. We predict that less complex pulse profiles will be observed at higher photon energies because the scattering atmospheres, which are supported by resonant Compton radiation pressure, become transparent to photons with energies greater than the cyclotron energy at the neutron star surface.

  15. Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre

    1999-10-01

    The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.

  16. Rainbows in energy- and angle-resolved ion scattering from surfaces

    SciTech Connect

    Tenner, A.D.; Gillen, K.T.; Horn, T.C.M.; Los, J.; Kleyn, A.W.

    1984-06-11

    The angular and energy distributions of K/sup +/ ions scattered at normal incidence with an initial energy of 35 eV on a W(110) surface were measured for various crystal orientations. The complex distributions show rainbows, which are due to both to extrema in the deflection functions for the two scattering angles as well as to an extremum in the final energy as a function of the impact parameter. With use of computer simulations with a nonadditive model potential all observed structures can be explained.

  17. Time gating for energy selection and scatter rejection: High-energy pulsed neutron imaging at LANSCE

    NASA Astrophysics Data System (ADS)

    Swift, Alicia; Schirato, Richard; McKigney, Edward; Hunter, James; Temple, Brian

    2015-09-01

    The Los Alamos Neutron Science Center (LANSCE) is a linear accelerator in Los Alamos, New Mexico that accelerates a proton beam to 800 MeV, which then produces spallation neutron beams. Flight path FP15R uses a tungsten target to generate neutrons of energy ranging from several hundred keV to ~600 MeV. The beam structure has micropulses of sub-ns width and period of 1.784 ns, and macropulses of 625 μs width and frequency of either 50 Hz or 100 Hz. This corresponds to 347 micropulses per macropulse, or 1.74 x 104 micropulses per second when operating at 50 Hz. Using a very fast, cooled ICCD camera (Princeton Instruments PI-Max 4), gated images of various objects were obtained on FP15R in January 2015. Objects imaged included blocks of lead and borated polyethylene; a tungsten sphere; and a tungsten, polyethylene, and steel cylinder. Images were obtained in 36 min or less, with some in as little as 6 min. This is novel because the gate widths (some as narrow as 10 ns) were selected to reject scatter and other signal not of interest (e.g. the gamma flash that precedes the neutron pulse), which has not been demonstrated at energies above 14 MeV. This proof-of-principle experiment shows that time gating is possible above 14MeV and is useful for selecting neutron energy and reducing scatter, thus forming clearer images. Future work (simulation and experimental) is being undertaken to improve camera shielding and system design and to precisely determine optical properties of the imaging system.

  18. Surface analysis of zeolites: An XPS, variable kinetic energy XPS, and low energy ion scattering study

    NASA Astrophysics Data System (ADS)

    Bare, Simon R.; Knop-Gericke, Axel; Teschner, Detre; Hävacker, Michael; Blume, Raoul; Rocha, Tulio; Schlögl, Robert; Chan, Ally S. Y.; Blackwell, N.; Charochak, M. E.; ter Veen, Rik; Brongersma, Hidde H.

    2016-06-01

    The surface Si/Al ratio in a series of zeolite Y samples has been obtained using laboratory XPS, synchrotron (variable kinetic energy) XPS, and low energy ion scattering (LEIS) spectroscopy. The non-destructive depth profile obtained using variable kinetic energy XPS is compared to that from the destructive argon ion bombardment depth profile from the lab XPS instrument. All of the data indicate that the near surface region of both the ammonium form and steamed Y zeolites is strongly enriched in aluminum. It is shown that when the inelastic mean free path of the photoelectrons is taken into account the laboratory XPS of aluminosilicates zeolites does not provide a true measurement of the surface stoichiometry, while variable kinetic energy XPS results in a more surface sensitive measurement. A comprehensive Si/Al concentration profile as a function of depth is developed by combining the data from the three surface characterization techniques. The LEIS spectroscopy reveals that the topmost atomic layer is further enriched in Al compared to subsequent layers.

  19. Low-energy multiple-Coulomb scattering in thick foils

    SciTech Connect

    Morrill, S.M.

    1984-01-01

    Angular and energy distributions were taken using proton and ..cap alpha..-particle beams of energies 2 to 10 MeV incident on a variety of thick foils. Foils were chosen from commonly used materials and to span the periodic table. Foil thicknesses were chosen which resulted in approximately 20-60% energy losses. The lower-energy experiments were done using the Brigham Young University 4-MeV Van de Graaff accelerator while the higher-energy experiments were performed using the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff. Angular distributions are characterized by the angles at which the distribution had dropped to the 1/e, 1/10, and 1/100 points of their initial values. Energy distributions are characterized by the mean energy and the width of the energy-straggling distribution of the emerging particle. Comparisons are made to the appropriate theories including the angular distribution theory of Nigam, Sundaresan, and Wu (NSW), and the straggling theory of Bethe. Improvements to the NSW method by using an effective energy and effective nuclear charge are discussed.

  20. Low-Energy Multiple-Coulomb Scattering in Thick Foils.

    NASA Astrophysics Data System (ADS)

    Morrill, Steven M.

    Angular and energy distributions were taken using proton and alpha-particle beams of energies 2--10 MeV incident on a variety of thick foils. Foils were chosen from commonly used materials and to span the periodic table. Foil thicknesses were chosen which resulted in approximately 20--60% energy losses. The lower-energy experiments were done using the Brigham Young University 4-MeV Van de Graaff accelerator while the higher-energy experiments were performed using the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff. Angular distributions were characterized by the angles at which the distribution had dropped to the 1/e, 1/10, and 1/100 points of their initial values. Energy distributions were characterized by the mean energy and the width of the energy straggling distribution of the emerging particle. Comparisons were made to the appropriate theories including the angular distribution theory of Nigam, Sundaresan, and Wu (NSW), and the straggling theory of Bethe. Improvements to the NSW method by using an effective energy and effective nuclear charge were discussed.

  1. Mathematical methods for restricted domain ternary liquid mixture free energy determination using light scattering

    NASA Astrophysics Data System (ADS)

    Wahle, Chris W.; Ross, David S.; Thurston, George M.

    2013-09-01

    We extend methods of solution of a light scattering partial differential equation for the free energy of mixing to apply to connected, isotropic ternary liquid composition domains that do not touch all three binary axes. To do so we mathematically analyze the problem of inferring needed Dirichlet boundary data, and solving for the free energy, with use of hypothetical static light scattering measurements that correspond to dielectric composition gradient vectors that have distinct directions. The physical idea behind the technique is that contrasting absorption properties of mixture components can result in such distinctly directed dielectric composition gradient vectors, due to their differing wavelength dependences of dielectric response. At suitably chosen wavelengths, contrasting light scattering efficiency patterns in the ternary composition triangle can then correspond to the same underlying free energy, and enlarge the scope of available information about the free energy, as shown here. We show how to use distinctly directed dielectric gradients to measure the free energy on both straight lines and curves within the ternary composition triangle, so as to provide needed Dirichlet conditions for light scattering partial differential equation solution. With use of Monte Carlo simulations of noisy light scattering data, we provide estimates of the overall system measurement time and sample spacing needed to determine the free energy to a desired degree of accuracy, for various angles between the assumed dielectric gradient vectors, and indicate how the measurement time depends on instrumental throughput parameters. The present analysis methods provide a way to use static light scattering to measure, directly, mixing free energies of many systems that contain such restricted liquid domains, including aqueous solutions of biological macromolecules, micellar mixtures and microemulsions, and many small molecule systems that are important in separation technology.

  2. Improving quantitative dosimetry in 177Lu-DOTATATE SPECT by energy window-based scatter corrections

    PubMed Central

    Lagerburg, Vera; Klausen, Thomas L.; Holm, Søren

    2014-01-01

    Purpose Patient-specific dosimetry of lutetium-177 (177Lu)-DOTATATE treatment in neuroendocrine tumours is important, because uptake differs across patients. Single photon emission computer tomography (SPECT)-based dosimetry requires a conversion factor between the obtained counts and the activity, which depends on the collimator type, the utilized energy windows and the applied scatter correction techniques. In this study, energy window subtraction-based scatter correction methods are compared experimentally and quantitatively. Materials and methods 177Lu SPECT images of a phantom with known activity concentration ratio between the uniform background and filled hollow spheres were acquired for three different collimators: low-energy high resolution (LEHR), low-energy general purpose (LEGP) and medium-energy general purpose (MEGP). Counts were collected in several energy windows, and scatter correction was performed by applying different methods such as effective scatter source estimation (ESSE), triple-energy and dual-energy window, double-photopeak window and downscatter correction. The intensity ratio between the spheres and the background was measured and corrected for the partial volume effect and used to compare the performance of the methods. Results Low-energy collimators combined with 208 keV energy windows give rise to artefacts. For the 113 keV energy window, large differences were observed in the ratios for the spheres. For MEGP collimators with the ESSE correction technique, the measured ratio was close to the real ratio, and the differences between spheres were small. Conclusion For quantitative 177Lu imaging MEGP collimators are advised. Both energy peaks can be utilized when the ESSE correction technique is applied. The difference between the calculated and the real ratio is less than 10% for both energy windows. PMID:24525900

  3. Double electron ionization in Compton scattering of high energy photons by helium atoms

    SciTech Connect

    Amusia, M.Y.; Mikhailov, A.I.

    1995-08-01

    The cross section for double-electron ionization of two-electron atoms and ions in Compton scattering of high energy photons is calculated. It is demonstrated that its dependence on the incoming photon frequency is the same as that for single-electron ionization. The ratio of {open_quotes}double-to-single{close_quotes} ionization in Compton scattering was found to be energy independent and almost identical with the corresponding value for photoionization. For the He atom it is 1.68%. This surprising result deserves experimental verification.

  4. Scattering of Halo Nuclei at Energies below and around the Coulomb Barrier

    NASA Astrophysics Data System (ADS)

    Borge, M. J. G.; Cubero, M.; Fernández-García, J. P.; Moro, A. M.; Pesudo, V.; Acosta, L.; Alcorta, M.; Alvarez, M. A. G.; Bender, P.; Buchmann, L.; Diget, C. A.; Di Pietro, A.; Escrig, D.; Falou, H. A.; Figuera, P. P.; Fulton, B. R.; Fynbo, H. O. U.; Galaviz, D.; Garnsworthy, A.; Gómez-Camacho, J.; Hackman, G.; Kanungo, R.; Lay, J. A.; Madurga, M.; Martel, I.; Mukha, I.; Nilsson, T.; Rodríguez-Gallardo, M.; Rusek, K.; Sánchez-Benítez, A. M.; Rajabali, M.; Sarazin, F.; Shotter, A.; Tengblad, O.; Unsworth, C.; Walden, P.

    The loosely bound structure of halo nuclei is predicted to affect the collisions with heavy targets at energies around the Coulomb barrier. We report here on the results on a series of experiments done at different facilities to study the behaviour of the scattering of the archetype of the halo nuclei: 6He, 11Li, and 11Be on heavy targets at energies below and around the Coulomb barrier. The results are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations (CDCC). The departure from Rutherford scattering is larger than expected. In first approximation the effect certainly scales with the loosely bound character of the projectile.

  5. Importance of light scattering properties of cloud particles on calculating the earth energy cycle

    NASA Astrophysics Data System (ADS)

    Letu, H.; Nakajima, T. Y.; Nagao, T. M.; Ishimoto, H.

    2013-12-01

    The Earth is an open system, and the energy cycle of the Earth is not always a certain amount. In other words, the energy cycle in the nature is imbalance. A better understanding of the earth energy cycle is very important to study global climate change. the IPCC-AR4 reported that the cloud in the atmosphere are still characterized by large uncertainties in the estimation of their effects on energy sysle of the Earth's atmosphere. There are two types of cloud in the atmosphere, which are Cirrus and warm water cloud. In order to strongly reflect visible wavelength from sun light, thick water cloud has the effect of cooling the earth surface. When Cirrus is compared to water cloud, temperature is almost lower. Thus, there is a feature that Cirrus is easy to absorb long-wave radiation than warm water cloud. However, in order to quantitatively evaluate the reflection and absorption characteristics of cloud on remote senssing application and energy cycle of the imbalance of nature, it is necessary to obtain the scattering properties of cloud particles. Since the shapes of the water cloud particle are close to spherical, scattering properties of the particles can be calculated accurately by the Mie theory. However, Cirrus particles have a complex shape, including hexagonal, plate, and other non- spherical shapes. Different from warm water cloud partical, it is required to use several different light scattering methods when calculating the light scattering properties of the non-spherical Cirrus cloud particals. Ishimoto et al. [2010, 2012] and Masuda et al. [2012] developed the Finite-Difference Time Domain method (FDTD) and Improved Geometrical-Optics Method (IGOM) for the solution of light scattering by non-spherical particles. Nakajima et al [1997,2009] developed the LIght Scattering solver for Arbitral Shape particle (Lisas)-Geometrical-Optics Method (GOM) and Surface Integral Equations Method of Müller-type (SIEMM) to calculate the light scattering properties for

  6. Computer simulation program for medium-energy ion scattering and Rutherford backscattering spectrometry

    NASA Astrophysics Data System (ADS)

    Nishimura, Tomoaki

    2016-03-01

    A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of 16O(4He, 4He)16O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.

  7. Scattering of Low Energy Electrons and Positrons from Hydrogenic Systems and Applications

    NASA Technical Reports Server (NTRS)

    Bhatia, Anand K.

    2007-01-01

    While the electron scatters from the target, the target no longer stays in its original form. One of the first methods to take into account the distortion of the target at low incident energies is the method of polarized orbitals. In this method the wave function for the process is written using the first-order perturbation theory and the equation for the scattering function is derived from the Schradinger equation. This method has been very successful in calculating the phase shifts and therefore the cross sections at various energies. The total wave function can be used to calculate photoionization cross sections. The disadvantage of this approach is that the method is not variational and therefore does not provide bounds on the phase shifts. These difficulties can be overcome by using the Feshbach projection operator formalism. This approach has been employed for the scattering of electrons and positrons from targets. Results of various calculations will be discussed.

  8. Interference effects in proton scattering on {sup 15}N nuclei at intermediate energies

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M.A.; Imambekov, O.; Krassovitskiy, P. M.

    2010-08-15

    The differential cross section for proton scattering on {sup 15}N nuclei is calculated within Glauber diffraction theory at energies of 0.2, 0.6, and 1.0 GeV. Use is made of the shell-model wave function for the {sup 15}N nucleus. The contribution of single and double collisions to the Glauber operator {Omega} is taken into account. The sensitivity of the differential cross sections to the contributions of scattering on nucleons from different shells, to the parameters of the elementary pN amplitude, and to the energy of projectile protons is investigated. It is shown that the interference between amplitudes corresponding to different collision multiplicities, as well as between the amplitudes for scattering on nucleons from different shells, determines special features of the cross section.

  9. Energy-dependent target widths in a coupled-channel scattering study

    SciTech Connect

    Canton, L.; Fraser, P. R.; Svenne, J. P.; Amos, K.; Knijff, D. van der; Karataglidis, S.

    2011-04-15

    The question of how the scattering cross section changes when the spectra of the colliding nuclei have low-excitation particle-emitting resonances is explored using a multichannel algebraic scattering method. As a test case, the particle-unstable nucleus {sup 8}Be has been considered as a target. Nucleon-nucleus scattering cross sections, as well as the spectra of the compound nuclei formed, have been determined from calculations that consider, as well as those that disregard, particle-emission widths of the target nuclear states. The resonant character of the unstable excited states introduces a problem because the low-energy tails of these resonances can intrude into the subthreshold, bound-state region. This unphysical behavior needs to be corrected by modifying, in an energy-dependent way, the shape of the target resonances from the usual Lorentzian form. The resonance function must smoothly reach zero at the elastic threshold. We explore herein a way of achieving this condition.

  10. Low-energy p-d scattering and {sup 3}He in pionless effective field theory

    SciTech Connect

    Koenig, Sebastian; Hammer, H.-W.

    2011-06-15

    We calculate low-energy proton-deuteron scattering in the framework of pionless effective field theory. In the quartet channel, we calculate the elastic scattering phase shift up to next-to-next-to-leading order in the power counting. In the doublet channel, we perform a next-to-leading-order calculation. We obtain good agreement with the available phase-shift analyses down to the scattering threshold. The phase shifts in the region of nonperturbative Coulomb interactions are calculated by using an optimized integration mesh. Moreover, the Coulomb contribution to the {sup 3}He-{sup 3}H binding energy difference is evaluated in first-order perturbation theory. We comment on the implications of our results for the power counting of subleading three-body forces.

  11. GPDs of the nucleons and elastic scattering at high energies

    NASA Astrophysics Data System (ADS)

    Selyugin, O. V.

    2012-07-01

    Taking into account the electromagnetic and gravitational form factors, calculated from a new set of t-dependent GPDs, a new model is built. The real part of the hadronic amplitude is determined only through complex s. In the framework of this model the quantitative description of all existing experimental data at 52.8 ≤sqrt{s} ≤ 1960 GeV, including the Coulomb range and large momentum transfers (0.0008≤| t|≤9.75 GeV2), is obtained with only three fitting high energy parameters. The comparison with the preliminary data of the TOTEM Collaboration at an energy of 7 TeV is made.

  12. Isospin breaking in low-energy pion-nucleon scattering

    SciTech Connect

    Gibbs, W.R.; Ai, L.; Kaufmann, W.B.

    1995-05-08

    We have analyzed low-energy pion-nucleon data for isospin invariance by comparing charge-exchange amplitudes derived from charge-exchange data with those predicted from recent {pi}{sup {plus_minus}}{ital p} elastic data through the application of isospin invariance. A discrepancy of the order of 7% is observed beyond the contributions of the {pi}{sup {plus_minus}}{ital p} Coulomb interaction and the hadronic mass differences.

  13. Trajectory analysis of low-energy and hyperthermal ions scattered from Cu(110)

    SciTech Connect

    McEachern, R. L.; Goodstein, D. M.; Cooper, B. H.

    1989-05-15

    We have investigated the trajectories of Na/sup +/ ions scattered from the Cu(110) surface in the <1/bar 1/0> and <001> azimuths for a range of incident energies from 56 eV to 4 keV. Our goal is to explain the trends observed in the energy spectra and determine what types of trajectories contribute to these spectra. Using the computer program SAFARI, we have performed simulations with trajectory analyses for 100-, 200-, and 400-eV scattering. We show results from the 100-eV simulations in both azimuths and compare them with the experimental data. The simulated energy spectra are in excellent agreement with the data. Ion trajectories and impact parameter plots from the simulations are used to determine the relative importance of different types of ion--surface-atom collisions. The simulations have shown that the striking differences observed in comparing the <1/bar 1/0> and <001> spectra are mostly due to ions which scatter from second-layer atoms. This system exhibits strong focusing onto the second-layer atoms by the first-layer rows, and the focusing is very sensitive to the spacing between the rows. At the lower beam energies, scattering from the second layer dominates the measured spectra.

  14. Trajectory analysis of low-energy and hyperthermal ions scattered from Cu(110)

    SciTech Connect

    McEachern, R.L.; Goodstein, D.M.; Cooper, B.H.

    1989-05-15

    Trajectories of Na{sup +} ions scattered from the Cu(110) surface in the <1 1bar 0> and <001> azimuths were studied for a range of incident energies from 56 eV to 4 keV. The goal is to explain the trends observed in the energy spectra and determine what types of trajectories contribute to these spectra. Using the computer program SAFARI, simulations were performed with trajectory analyses for 100-, 200-, and 400-eV scattering. We show results from the 100-eV simulations in both azimuths and compare them with the experimental data. The simulated energy spectra are in excellent agreement with the data. Ion trajectories and impact parameter plots from the simulations are used to determine the relative importance of different types of ion-surface-atom collisions. The simulations have shown that the striking differences observed in comparing the <1 1bar 0> and <001> spectra are mostly due to ions which scatter from second-layer atoms. This system exhibits strong focusing onto the second-layer atoms by the first-layer rows, and the focusing is very sensitive to the spacing between the rows. At the lower beam energies, scattering from the second layer dominates the measured spectra.

  15. High precision elastic α scattering on the even-odd 115In nucleus at low energies

    NASA Astrophysics Data System (ADS)

    Kiss, G. G.; Szücs, T.; Mohr, P.; Fülöp, Zs; Gyürky, Gy; Halász, Z.; Soha, R. F.; Somorjai, E.; Ornelas, A.; Galaviz, D.; Yalçın, C.; Güray, R. T.; Özkan, N.

    2016-01-01

    Elastic alpha scattering cross sections on the even-odd 115In nucleus have been measured at energies Elab. = 16.15 MeV and 19.50 MeV. The high precision experimental data are used to derive the parameters of a local a nucleus optical potential.

  16. Proton scattering on carbon nuclei in bichromatic laser field at moderate energies

    NASA Astrophysics Data System (ADS)

    Barna, I. F.; Varró, S.

    2016-02-01

    We present the general theory for proton nuclei scattering in a bichromatic laser field. As a physical example we consider proton collision on 12C at 49 MeV/amu moderate energies in the field of a titan sapphire laser with its second harmonic.

  17. Two-loop Bhabha scattering at high energy beyond leading power approximation

    NASA Astrophysics Data System (ADS)

    Penin, Alexander A.; Zerf, Nikolai

    2016-09-01

    We evaluate the two-loop O (me2/ s) contribution to the wide-angle high-energy electron-positron scattering in the double-logarithmic approximation. The origin and the general structure of the power-suppressed double logarithmic corrections are discussed in detail.

  18. Spectral Study of a Broad Energy HPGe Detector for First Measurement of Coherent Neutrino Scattering

    NASA Astrophysics Data System (ADS)

    Surbrook, Jason; Green, Matthew

    2014-09-01

    Intense neutrino flux at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) in the energy domain below Eν = 50 MeV makes SNS a suitable location for measurement of Coherent Neutrino Scattering. Coherent scattering is assumed to occupy vital roles in supernovae (SN) events and measurement offers promising insight into SN mechanics and advancements in SN- ν detection. Furthermore, this interaction is well-calculable and therefore, a strong test of the Standard Model. P-Type Point Contact High-purity germanium detectors are excellent candidates for this measurement due to their sensitivity to low-energy nuclear recoils. One such, a Canberra Broad Energy HPGe detector, was tested for quality degradation from exposure to fast neutrons in the SNS target building, to assess usefulness in a future coherent scattering experiment. Analysis of the lead-shielded spectra was handled using tools developed for the Majorana Demonstrator neutrinoless double-beta decay experiment. Broad spectrum energy resolution and 68Ge decay rates were calculated. This poster will present findings that will help determine this detector's eligibility and exposure limitations for measurement in a future coherent neutrino scattering experiment at the SNS.

  19. Two-loop Bhabha scattering at high energy beyond leading power approximation

    NASA Astrophysics Data System (ADS)

    Penin, Alexander A.; Zerf, Nikolai

    2016-09-01

    We evaluate the two-loop O (me2/s) contribution to the wide-angle high-energy electron-positron scattering in the double-logarithmic approximation. The origin and the general structure of the power-suppressed double logarithmic corrections are discussed in detail.

  20. Vanishing rainbows near orbiting and the energy dependence of rainbow scattering - Relation to properties of the potential. [molecular beam scattering cross sections

    NASA Technical Reports Server (NTRS)

    Greene, E. F.; Hall, R. B.; Mason, E. A.

    1975-01-01

    The energy threshold behavior of elastic rainbow scattering near the transition to orbiting is derived. Analysis of the energy dependence of the rainbow angle shows that the full range from high energies down to orbiting can be fitted with two parameters. Thus, measurements of the rainbow angle can give essentially only two pieces of information about the potential. For potentials of common shapes, such measurements are sensitive to regions of the potential just beyond the minimum and give information about the shape of the potential in this range. However, neither a minimum nor a point of inflection in the potential is necessary for rainbow scattering.

  1. Resonant charge transfer in low-energy ion scattering: Information depth in the reionization regime.

    PubMed

    Primetzhofer, D; Spitz, M; Taglauer, E; Bauer, P

    2011-11-01

    Time-Of-Flight Low-energy ion scattering (TOF-LEIS) experiments were performed for He(+) ions scattered from Cu(100) and Cu(0.5)Au(0.5)(100). Probabilities for resonant neutralization and reionization in close collisions were deduced in a wide energy range. To learn about the information depth in LEIS, in a next step ion spectra were analyzed for polycrystalline Cu samples. The relative yield of backscattered projectiles, which have undergone distinct charge exchange processes, was calculated. Results indicate a strong contribution to the ion yield that origins from particles reionized in a close collision in deeper layers when experiments are performed at energies where reionization is prominent. The surface sensitivity of the ion signal at different energies is quantified. Based on these results, the total ion spectrum was quantitatively modelled by two consistent, but different approaches. PMID:22053118

  2. An investigation into electron scattering from pyrazine at intermediate and high energies

    SciTech Connect

    Sanz, A. G.; Fuss, M. C.; Blanco, F.; Gorfinkiel, J. D.; Almeida, D.; Ferreira da Silva, F.; Limão-Vieira, P.; Brunger, M. J.; García, G.

    2013-11-14

    Total electron scattering cross sections for pyrazine in the energy range 10–500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV incident electron energies. The present experimental and theoretical total cross sections show a good level of agreement, to within 10%, in the overlapping energy range. Consistency of these results with previous calculations (i.e., the R-matrix and Schwinger Multichannel methods) and elastic scattering measurements at lower energies, below 10 eV, is also discussed.

  3. Interatomic scattering in energy dependent photoelectron spectra of Ar clusters

    SciTech Connect

    Patanen, M.; Benkoula, S.; Nicolas, C.; Goel, A.; Antonsson, E.; Neville, J. J.; Miron, C.

    2015-09-28

    Soft X-ray photoelectron spectra of Ar 2p levels of atomic argon and argon clusters are recorded over an extended range of photon energies. The Ar 2p intensity ratios between atomic argon and clusters’ surface and bulk components reveal oscillations similar to photoelectron extended X-ray absorption fine structure signal (PEXAFS). We demonstrate here that this technique allows us to analyze separately the PEXAFS signals from surface and bulk sites of free-standing, neutral clusters, revealing a bond contraction at the surface.

  4. Interatomic scattering in energy dependent photoelectron spectra of Ar clusters

    NASA Astrophysics Data System (ADS)

    Patanen, M.; Benkoula, S.; Nicolas, C.; Goel, A.; Antonsson, E.; Neville, J. J.; Miron, C.

    2015-09-01

    Soft X-ray photoelectron spectra of Ar 2p levels of atomic argon and argon clusters are recorded over an extended range of photon energies. The Ar 2p intensity ratios between atomic argon and clusters' surface and bulk components reveal oscillations similar to photoelectron extended X-ray absorption fine structure signal (PEXAFS). We demonstrate here that this technique allows us to analyze separately the PEXAFS signals from surface and bulk sites of free-standing, neutral clusters, revealing a bond contraction at the surface.

  5. Multiple scattering calculations of relativistic electron energy loss spectra

    NASA Astrophysics Data System (ADS)

    Jorissen, K.; Rehr, J. J.; Verbeeck, J.

    2010-04-01

    A generalization of the real-space Green’s-function approach is presented for ab initio calculations of relativistic electron energy loss spectra (EELS) which are particularly important in anisotropic materials. The approach incorporates relativistic effects in terms of the transition tensor within the dipole-selection rule. In particular, the method accounts for relativistic corrections to the magic angle in orientation resolved EELS experiments. The approach is validated by a study of the graphite CK edge, for which we present an accurate magic angle measurement consistent with the predicted value.

  6. Implications of unitarity for low-energy W+/-L, ZL scattering

    NASA Astrophysics Data System (ADS)

    Durand, Loyal; Johnson, James M.; Maher, Peter N.

    1991-07-01

    We investigate the partial-wave scattering of longitudinally polarized W+/- and Z bosons for energies MW<< √s <energies √s <

  7. Two-loop self-energy and multiple scattering at finite temperature

    SciTech Connect

    Kapusta, J. I.; Wong, S. M. H.

    2001-08-15

    One- and two-loop self-energies are worked out explicitly for a heavy scalar field interacting weakly with a light self-interacting scalar field at finite temperature. The ring or daisy diagrams and a set of necklace diagrams can be summed simultaneously. This simple model serves to illustrate the connection between multiloop self-energy diagrams and multiple scattering in a medium.

  8. Ultrahigh energy neutrino-nucleon scattering and parton distributions at small x

    SciTech Connect

    Henley, Ernest M.; Jalilian-Marian, Jamal

    2006-05-01

    The cross section for ultrahigh energy neutrino-nucleon scattering is very sensitive to the parton distributions at very small values of Bjorken x (x{<=}10{sup -4}). We numerically investigate the effects of modifying the behavior of the gluon distribution function at very small x in the DGLAP evolution equation. We then use the Color Glass Condensate formalism to calculate the neutrino-nucleon cross section at ultrahigh energies and compare the result with those based on modification of DGLAP evolution equation.

  9. Scattering theory and ground-state energy of Dirac fermions in graphene with two Coulomb impurities

    NASA Astrophysics Data System (ADS)

    Klöpfer, Denis; De Martino, Alessandro; Matrasulov, Davron U.; Egger, Reinhold

    2014-08-01

    We study the physics of Dirac fermions in a gapped graphene monolayer containing two Coulomb impurities. For the case of equal impurity charges, we discuss the ground-state energy using the linear combination of atomic orbitals (LCAO) approach. For opposite charges of the Coulomb centers, an electric dipole potential results at large distances. We provide a nonperturbative analysis of the corresponding low-energy scattering problem.

  10. A triple energy window scatter subtraction approach for quantitative anger camera imaging of iodine-131

    SciTech Connect

    Grant, E.J.; Macey, D.J.; Bayouth, J.E.

    1994-05-01

    Dose estimates for organs and tumor volumes in radioimmunotherapy with I-131 frequently depend on in-vivo quantitation methods using planar Anger camera images. Compton scatter and collimator septal penetration result in overestimation of activity and dose. The objective of this study was to assess the effectiveness of a triple energy window subtraction method for quantitative imaging of I-131. The energy spectrum of I-131 was modeled as a superposition of the spectra of Cr-51 (320 keV) and Cs-137 (662 keV). Images were acquired with three adjacent 15% energy windows--photopeak(PP), upper scatter(US), and lower scatter(LS)--for small sources of these radionuclides. The PP window was centered at 364 keV for I-131 and Cs-137 and 320 keV for Cr-51. Three scatter multipliers were derived from analysis of count profiles of the Cs-137 and Cr-51 images, and used to sequentially remove septal penetration and scatter events included in the 364 keV photopeak of I-131. This method was tested by acquiring images of an abdominal phantom containing a liver, spleen and spherical {open_quotes}tumor{close_quotes} filled with different concentrations of I-131, both with and without background activity in the surrounding phantom. A body thickness attenuation compensation factor was applied to the geometric mean of the conjugate view counts using a narrow beam linear attenuation coefficient of 0.11 cm{sup -1}. With scatter subtraction, the accuracy and reproducibility of activity quantitation was improved because the background count density was more uniformly scored. Also, the influence of different activity concentrations in source organs relative to background on the accuracy of quantitation was removed, and the perimeters of organs were more clearly defined. This method has been used to provide improved dose estimates for I-131 labeled antibody therapy in breast cancer patients.

  11. A simple scatter correction method for dual energy contrast-enhanced digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Lu, Yihuan; Lau, Beverly; Hu, Yue-Houng; Zhao, Wei; Gindi, Gene

    2014-03-01

    Dual-Energy Contrast Enhanced Digital Breast Tomosynthesis (DE-CE-DBT) has the potential to deliver diagnostic information for vascularized breast pathology beyond that available from screening DBT. DE-CE-DBT involves a contrast (iodine) injection followed by a low energy (LE) and a high energy (HE) acquisitions. These undergo weighted subtraction then a reconstruction that ideally shows only the iodinated signal. Scatter in the projection data leads to "cupping" artifacts that can reduce the visibility and quantitative accuracy of the iodinated signal. The use of filtered backprojection (FBP) reconstruction ameliorates these types of artifacts, but the use of FBP precludes the advantages of iterative reconstructions. This motivates an effective and clinically practical scatter correction (SC) method for the projection data. We propose a simple SC method, applied at each acquisition angle. It uses scatter-only data at the edge of the image to interpolate a scatter estimate within the breast region. The interpolation has an approximately correct spatial profile but is quantitatively inaccurate. We further correct the interpolated scatter data with the aid of easily obtainable knowledge of SPR (scatter-to-primary ratio) at a single reference point. We validated the SC method using a CIRS breast phantom with iodine inserts. We evaluated its efficacy in terms of SDNR and iodine quantitative accuracy. We also applied our SC method to a patient DE-CE-DBT study and showed that the SC allowed detection of a previously confirmed tumor at the edge of the breast. The SC method is quick to use and may be useful in a clinical setting.

  12. On triplet low-energy parameters of nucleon-nucleon scattering

    SciTech Connect

    Babenko, V. A.; Petrov, N. M.

    2006-09-15

    Triplet low-energy parameters of neutron-proton scattering, including high-order shape parameters, are calculated on the basis of approximating the effective-range function k cot {delta}{sub t} by polynomials and rational functions with the aid of the latest experimental data on phase shifts from the SAID nucleon-nucleon database. With the resulting values of the low-energy parameters, a good description of phase shifts over a broad energy interval is obtained by using the effective-range expansion featuring a small number of terms. The properties of the deuteron that were calculated on the basis of the values found for the triplet low-energy parameters of scattering agree very well with experimental values. The triplet low-energy parameters and the properties of the deuteron that were obtained here by using present-day data from the SAID database differ markedly from the analogous results obtained for data of the Nijmegen group. Possible reasons behind this discrepancy are discussed. Highly precise new approximate formulas for determining the shape parameter v{sub 2} are proposed and are shown to be efficient in calculations. The effective-range expansion for the D wave is considered, and preliminary results of calculations of low-energy scattering parameters for this case are obtained.

  13. Measurements of ultra-low-energy electron scattering cross sections of atoms and molecules

    SciTech Connect

    Kitajima, M.; Shigemura, K.; Kurokawa, M.; Odagiri, T.; Kato, H.; Hoshino, M.; Tanaka, H.; Ito, K.

    2014-03-05

    A new experimental technique for the total cross section measurements of ultra-low energy electron collisions with atoms and molecules utilizing the synchrotron radiation is presented. The technique employs a combination of the penetrating field technique and the threshold photoionization of rare gas atoms using the synchrotron radiation as an electron source in order to produce a high resolution electron beam at very low energy. Absolute total cross sections for electron scattering from He, Ne, Ar, Kr, and Xe in the energy region from extremely low electron energy to 20 eV are presented.

  14. Structure of elastic p-p scattering at low and high energies

    NASA Astrophysics Data System (ADS)

    Arash, Firooz; Moravcsick, Michael J.; Goldstein, Gary R.

    1985-02-01

    It is observed that p-p elastic scattering at 90° between 0.3 and 1.0 GeV is described by planar-transverse amplitude of which two are equal in magnitude and one is about three times larger in magnitude. This feature, extrapolated to much higher energies, is used to predict p-p polarization quantities, in part by itself, in part in combination with the extension of another, previously observed feature of planar-transverse amplitudes. Comparison with existing data is favorable. Predictions are then made for other, yet unmeasured but readily measurable polarization quantities for p-p elastic scattering.

  15. Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma

    SciTech Connect

    Dzhumagulova, K. N. Shalenov, E. O.; Ramazanov, T. S.

    2015-08-15

    Elastic scattering of electrons by hydrogen atoms in a dense semiclassical hydrogen plasma for low impact energies has been studied. Differential scattering cross sections were calculated within the effective model of electron-atom interaction taking into account the effect of screening as well as the quantum mechanical effect of diffraction. The calculations were carried out on the basis of the phase-function method. The influence of the diffraction effect on the Ramsauer–Townsend effect was studied on the basis of a comparison with results made within the effective polarization model of the Buckingham type.

  16. Deuteron scattering on {sup 6}Li at an energy of 25 MeV

    SciTech Connect

    Burtebayev, N.; Artemov, S. V.; Duisebayev, B. A.; Kerimkulov, Zh. K.; Kuranov, S. B.; Sakuta, S. B.

    2010-05-15

    At an energy of 25 MeV and in the angular range 7{sup o}-175{sup o} in the laboratory frame, angular distributions were measured for elastic deuteron scattering on {sup 6}Li nuclei and for the respective inelastic-scattering processes accompanied by the transitions to the ground state (1+) of the {sup 6}Li nucleus and to its excited state at E{sub x} = 2.186 MeV (J{sup {pi}} = 3{sup +}). The resulting data were analyzed on the basis of the optical model of the nucleus and the coupled-reaction-channel method with allowance for the mechanism of alpha-particle-cluster exchange. It is shown that only upon including, in the analysis, channel coupling and the exchange mechanism can the experimental cross sections for elastic and inelastic scattering be reproduced over the entire range of angles.

  17. Elastic scattering of positrons on mercury: A negative-energy Dirac-Fock treatment

    SciTech Connect

    Sienkiewicz, J.E.; Baylis, W.E. )

    1991-02-01

    In a new extension of the Dirac-Fock method, calculations have been performed on the 80 electrons of mercury (in 22 {ital nlj} orbitals) plus one continuum electron of negative energy less than {minus}{ital mc}{sup 2}. The asymptotic form of the numerical wave function of the negative-energy electron determines the phase shifts for the elastic scattering of positrons on Hg. The self-consistent-field calculations include the usual exchange interaction between electrons. The exchange between the bound Hg electrons and the negative-energy continuum electron represents the positron-electron annihilation-creation process. Such effects are usually computed in quantum electrodynamics to some order of approximation in a perturbation expansion. We believe ours is the first Dirac-Fock calculation of this effect, but we find its influence on the elastic positron scattering to be negligible.

  18. Backward scattering of low-energy antiprotons by highly charged and neutral uranium: Coulomb glory

    SciTech Connect

    Maiorova, A. V.; Telnov, D. A.; Shabaev, V. M.; Tupitsyn, I. I.; Plunien, G.; Stoehlker, T.

    2007-09-15

    Collisions of antiprotons with He-, Ne-, Ni-like, bare, and neutral uranium are studied theoretically for scattering angles close to 180 deg. and antiproton energies in the interval from 100 eV to 10 keV. We investigate the Coulomb glory effect which is caused by a screening of the Coulomb potential of the nucleus and results in a prominent maximum of the differential cross section in the backward direction at some energies of the incident particle. We found that for larger numbers of electrons in the ion the effect becomes more pronounced and shifts to higher energies of the antiproton. On the other hand, a maximum of the differential cross section in the backward direction can also be found in the scattering of antiprotons on a bare uranium nucleus. The latter case can be regarded as a manifestation of the screening property of the vacuum-polarization potential in nonrelativistic collisions of heavy particles.

  19. Neutral Current Neutrino-{sup 116}Cd Reaction Cross Sections at Low and Intermediate Energies

    SciTech Connect

    Balasi, K. G.; Kosmas, T. S.; Divari, P. C.; Chasioti, V. C.

    2008-01-24

    Differential and integrated cross sections for inelastic scattering of electron neutrinos from a {sup 116}Cd target at low and intermediate neutrino energies ({epsilon}{sub i}{<=}100 MeV) are presented. The nuclear wave functions for the initial and final nuclear states are constructed in the context of quasiparticle random phase approximation (QRPA). By exploiting the results of these cross sections, we study the response of {sup 116}Cd to supernova neutrino spectra by utilizing the folding procedure and employing a two-parameter Fermi-Dirac distribution for the supernova neutrino spectra. Our results show that, this isotope may play a significant role in supernova neutrino detection, in addition to its use in double-beta-decay experiments (COBRA, etc)

  20. Pole structure from energy-dependent and single-energy fits to GWU-SAID π N elastic scattering data

    NASA Astrophysics Data System (ADS)

    Švarc, Alfred; Hadžimehmedović, Mirza; Osmanović, Hedim; Stahov, Jugoslav; Workman, Ron L.

    2015-01-01

    The pole structure of the current George Washington University (GWU-SAID) partial-wave analysis of elastic π N scattering and η N production data is studied. Pole positions and residues are extracted from both the energy-dependent and single-energy fits, using two different methods. For the energy-dependent fits, both contour integration and a Laurent + Pietarinen approach are used. In the case of single-energy fits, the Laurent+Pietarinen approach is used. Errors are estimated and the two sets of results are compared to other fits to data.

  1. Scattering framework for two particles with isotropic spin-orbit coupling applicable to all energies

    NASA Astrophysics Data System (ADS)

    Guan, Q.; Blume, D.

    2016-08-01

    Previous work developed a K -matrix formalism applicable to positive energies for the scattering between two s -wave interacting particles with two internal states, isotropic spin-orbit coupling and vanishing center-of-mass momentum [H. Duan, L. You, and B. Gao, Phys. Rev. A 87, 052708 (2013)., 10.1103/PhysRevA.87.052708]. This work extends the formalism to the entire energy regime. Explicit solutions are obtained for the total angular momentum J =0 and 1 channels. The behavior of the partial cross sections in the negative energy regime is analyzed in detail. We find that the leading contributions to the partial cross sections at the negative energy thresholds are governed by the spin-orbit coupling strength kso and the mass ratio. The fact that these contributions are independent of the two-body scattering length as is a direct consequence of the effective reduction of the dimensionality, and hence of the density of states, near the scattering thresholds due to the single-particle spin-orbit coupling terms. The results are analytically continued to the energy regime where bound states exist. It is shown that our results are consistent with results obtained by alternative approaches. Our formulation, which can be regarded as an extension of the standard textbook partial wave decomposition, can be generalized to two-body systems with other types of spin-orbit coupling, including cases where the center-of-mass momentum does not vanish.

  2. Impact of Phonon Surface Scattering on Thermal Energy Distribution of Si and SiGe Nanowires.

    PubMed

    Malhotra, Abhinav; Maldovan, Martin

    2016-01-01

    Thermal transport in nanostructures has attracted considerable attention in the last decade but the precise effects of surfaces on heat conduction have remained unclear due to a limited accuracy in the treatment of phonon surface scattering phenomena. Here, we investigate the impact of phonon-surface scattering on the distribution of thermal energy across phonon wavelengths and mean free paths in Si and SiGe nanowires. We present a rigorous and accurate description of phonon scattering at surfaces and predict and analyse nanowire heat spectra for different diameters and surface conditions. We show that the decrease in the diameter and increased roughness and correlation lengths makes the heat phonon spectra significantly shift towards short wavelengths and mean free paths. We also investigate the emergence of phonon confinement effects for small diameter nanowires and different surface scattering properties. Computed results for bulk materials show excellent agreement with recent experimentally-based approaches that reconstruct the mean-free-path heat spectra. Our phonon surface scattering model allows for an accurate theoretical extraction of heat spectra in nanowires and contributes to elucidate the development of critical phonon transport modes such as phonon confinement and coherent interference effects. PMID:27174699

  3. Impact of Phonon Surface Scattering on Thermal Energy Distribution of Si and SiGe Nanowires

    NASA Astrophysics Data System (ADS)

    Malhotra, Abhinav; Maldovan, Martin

    2016-05-01

    Thermal transport in nanostructures has attracted considerable attention in the last decade but the precise effects of surfaces on heat conduction have remained unclear due to a limited accuracy in the treatment of phonon surface scattering phenomena. Here, we investigate the impact of phonon-surface scattering on the distribution of thermal energy across phonon wavelengths and mean free paths in Si and SiGe nanowires. We present a rigorous and accurate description of phonon scattering at surfaces and predict and analyse nanowire heat spectra for different diameters and surface conditions. We show that the decrease in the diameter and increased roughness and correlation lengths makes the heat phonon spectra significantly shift towards short wavelengths and mean free paths. We also investigate the emergence of phonon confinement effects for small diameter nanowires and different surface scattering properties. Computed results for bulk materials show excellent agreement with recent experimentally-based approaches that reconstruct the mean-free-path heat spectra. Our phonon surface scattering model allows for an accurate theoretical extraction of heat spectra in nanowires and contributes to elucidate the development of critical phonon transport modes such as phonon confinement and coherent interference effects.

  4. Precision Determination of Electron Scattering Angle by Differential Nuclear Recoil Energy Method

    SciTech Connect

    Liyanage, Nilanga; Saenboonruang, Kiadtisak

    2015-09-01

    The accurate determination of the scattered electron angle is crucial to electron scattering experiments, both with open-geometry large-acceptance spectrometers and ones with dipole-type magnetic spectrometers for electron detection. In particular, for small central-angle experiments using dipole-type magnetic spectrometers, in which surveys are used to measure the spectrometer angle with respect to the primary electron beam, the importance of the scattering angle determination is emphasized. However, given the complexities of large experiments and spectrometers, the accuracy of such surveys is limited and insufficient to meet demands of some experiments. In this article, we present a new technique for determination of the electron scattering angle based on an accurate measurement of the primary beam energy and the principle of differential nuclear recoil. This technique was used to determine the scattering angle for several experiments carried out at the Experimental Hall A, Jefferson Lab. Results have shown that the new technique greatly improved the accuracy of the angle determination compared to surveys.

  5. Precision determination of electron scattering angle by differential nuclear recoil energy method

    SciTech Connect

    Liyanage, N.; Saenboonruang, K.

    2015-12-01

    The accurate determination of the scattered electron angle is crucial to electron scattering experiments, both with open-geometry large-acceptance spectrometers and ones with dipole-type magnetic spectrometers for electron detection. In particular, for small central-angle experiments using dipole-type magnetic spectrometers, in which surveys are used to measure the spectrometer angle with respect to the primary electron beam, the importance of the scattering angle determination is emphasized. However, given the complexities of large experiments and spectrometers, the accuracy of such surveys is limited and insufficient to meet demands of some experiments. In this article, we present a new technique for determination of the electron scattering angle based on an accurate measurement of the primary beam energy and the principle of differential nuclear recoil. This technique was used to determine the scattering angle for several experiments carried out at the Experimental Hall A, Jefferson Lab. Results have shown that the new technique greatly improved the accuracy of the angle determination compared to surveys.

  6. Impact of Phonon Surface Scattering on Thermal Energy Distribution of Si and SiGe Nanowires

    PubMed Central

    Malhotra, Abhinav; Maldovan, Martin

    2016-01-01

    Thermal transport in nanostructures has attracted considerable attention in the last decade but the precise effects of surfaces on heat conduction have remained unclear due to a limited accuracy in the treatment of phonon surface scattering phenomena. Here, we investigate the impact of phonon-surface scattering on the distribution of thermal energy across phonon wavelengths and mean free paths in Si and SiGe nanowires. We present a rigorous and accurate description of phonon scattering at surfaces and predict and analyse nanowire heat spectra for different diameters and surface conditions. We show that the decrease in the diameter and increased roughness and correlation lengths makes the heat phonon spectra significantly shift towards short wavelengths and mean free paths. We also investigate the emergence of phonon confinement effects for small diameter nanowires and different surface scattering properties. Computed results for bulk materials show excellent agreement with recent experimentally-based approaches that reconstruct the mean-free-path heat spectra. Our phonon surface scattering model allows for an accurate theoretical extraction of heat spectra in nanowires and contributes to elucidate the development of critical phonon transport modes such as phonon confinement and coherent interference effects. PMID:27174699

  7. Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration

    SciTech Connect

    Xu, Tong; Chen, Min Li, Fei-Yu; Yu, Lu-Le; Sheng, Zheng-Ming; SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG ; Zhang, Jie; Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190

    2014-01-06

    We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

  8. On the importance of full-dimensionality in low-energy molecular scattering calculations

    PubMed Central

    Faure, Alexandre; Jankowski, Piotr; Stoecklin, Thierry; Szalewicz, Krzysztof

    2016-01-01

    Scattering of H2 on CO is of great importance in astrophysics and also is a benchmark system for comparing theory to experiment. We present here a new 6-dimensional potential energy surface for the ground electronic state of H2-CO with an estimated uncertainty of about 0.6 cm−1 in the global minimum region, several times smaller than achieved earlier. This potential has been used in nearly exact 6-dimensional quantum scattering calculations to compute state-to-state cross-sections measured in low-energy crossed-beam experiments. Excellent agreement between theory and experiment has been achieved in all cases. We also show that the fully 6-dimensional approach is not needed with the current accuracy of experimental data since an equally good agreement with experiment was obtained using only a 4-dimensional treatment, which validates the rigid-rotor approach widely used in scattering calculations. This finding, which disagrees with some literature statements, is important since for larger systems full-dimensional scattering calculations are currently not possible. PMID:27333870

  9. On the importance of full-dimensionality in low-energy molecular scattering calculations.

    PubMed

    Faure, Alexandre; Jankowski, Piotr; Stoecklin, Thierry; Szalewicz, Krzysztof

    2016-01-01

    Scattering of H2 on CO is of great importance in astrophysics and also is a benchmark system for comparing theory to experiment. We present here a new 6-dimensional potential energy surface for the ground electronic state of H2-CO with an estimated uncertainty of about 0.6 cm(-1) in the global minimum region, several times smaller than achieved earlier. This potential has been used in nearly exact 6-dimensional quantum scattering calculations to compute state-to-state cross-sections measured in low-energy crossed-beam experiments. Excellent agreement between theory and experiment has been achieved in all cases. We also show that the fully 6-dimensional approach is not needed with the current accuracy of experimental data since an equally good agreement with experiment was obtained using only a 4-dimensional treatment, which validates the rigid-rotor approach widely used in scattering calculations. This finding, which disagrees with some literature statements, is important since for larger systems full-dimensional scattering calculations are currently not possible. PMID:27333870

  10. Universality of entanglement creation in low-energy two-dimensional scattering

    SciTech Connect

    Weder, Ricardo

    2013-10-15

    We prove that the entanglement created in the low-energy scattering of two particles in two dimensions is given by a universal coefficient that is independent of the interaction potential. This is strikingly different from the three dimensional case, where it is proportional to the total scattering cross section. Before the collision the state is a product of two normalized Gaussians. We take the purity as the measure of the entanglement after the scattering. We give a rigorous computation, with error bound, of the leading order of the purity at low-energy. For a large class of potentials, that are not-necessarily spherically symmetric, we prove that the low-energy behavior of the purity, P, is universal. It is given by P=1−1/((ln(σ/ħ)){sup 2}) E, where σ is the variance of the Gaussians and the entanglement coefficient, E, depends only on the masses of the particles and not on the interaction potential. There is a strong dependence of the entanglement in the difference of the masses. The minimum is when the masses are equal, and it increases strongly with the difference of the masses. -- Highlights: •The entanglement in low-energy scattering in two dimensions is universal. It is independent of the potential. •We take the purity as the measure of entanglement. •We give a rigorous computation of the leading order of the purity at low energy. •The created entanglement depends strongly on the masses of the particles. •It takes its minimum for equal masses and it increases strongly with the difference of the masses.

  11. Numerical investigation of the single scattering albedo of radiant energy passing through polydisperse crystalline media

    NASA Astrophysics Data System (ADS)

    Shefer, O. V.; Shefer, V. A.; Sinyukova, E. A.

    2014-12-01

    Studies of the role of atmospheric formations and cosmic dust clouds in the transmission of radiation is one of the most uncertain and difficult problems in astrophysics and climatology. One of the main tasks of practical astrophysics is the interpretation of the results of observations of space objects. There is a necessity of describing the propagation of electromagnetic waves in the environment. In this paper, applying the numerical methods, we study the optical characteristics of polydisperse media consisting of randomly oriented and preferentially oriented crystals, taking into account the distribution function of particle sizes. Particles of spherical shape and ensembles preferentially oriented plate crystals are considered as models. Mie theory and method of physical optics are used to calculate the scattering characteristics. Numerical study of the effects of extinction, scattering and absorption on the single scattering albedo of radiation allowed us to establish the basic patterns of the passage of radiant energy through a translucent medium. At the visible range of wavelengths, both for small and large particles, the single scattering albedo is almost equal to 1. The spectral course of this optical performance is mainly determined by the refractive index of the particles. Features of wave dependence of single scattering albedo are associated with microphysical parameters of the environment, which are more pronounced when the attenuation of the radiation is determined mainly by the scattering. Higher values of the absorption index and optical thickness of the crystal reduce the value of the single scattering albedo, smoothing the features of its spectral course. Values of the absorption index of substance, as value of the order of 0.1, do not lead to a decrease of the single scattering albedo as it is less than 0.5. This allows us to conclude that we should not neglect the microphysical characteristics of the crystals even by strong absorption of radiant

  12. High-energy electron scattering from TiO2 surfaces

    NASA Astrophysics Data System (ADS)

    Vos, M.; Grande, P. L.

    2015-07-01

    Electron scattering experiments at keV energies from a TiO2 surface are presented. The paper aims to give an overview of the wide variety of information that can be extracted from such experiments. If the elastic scattering cross sections are known these experiments give the sample composition, if the composition is known one can extract the ratio of the elastic cross sections. In the experiments described here the ratio of the Ti and O cross sections deviates noticeably from the one calculated from the Rutherford formula. The peak widths give access to the mean kinetic energies of the atoms present. We show that the mean kinetic energy of Ti atoms is less than that of O atoms, but both kinetic energies are still affected by quantum effects, i.e. are larger than 3 / 2 kT . We extract an estimate of the dielectric function of TiO2 by extending the measurement up to 100 eV energy loss. At these high energies the determination of the dielectric function from the measured energy loss spectrum is relatively simple, as the contribution of surface excitations is small and the obtained loss function is closely related to the dielectric function in the optical limit. Finally, we use the technique to monitor the surface after sputtering with Ar+ ions, and observe both differences in composition and electronic structure induced by sputtering that disappear again after annealing.

  13. Low-energy electron scattering from CO. 2: Ab-initio study using the frame-transformation theory

    NASA Technical Reports Server (NTRS)

    Chandra, N.

    1976-01-01

    The Wigner-Eisenbud R matrix method has been combined with the frame transformation theory to study electron scattering from molecular systems. The R matrix, calculated at the boundary point of the molecular core radius, has been transformed to the space frame in order to continue the solution of the scattering equations in the outer region where rotational motion of the nuclei is taken into account. This procedure has been applied to a model calculation of thermal energy electron scattering from CO.

  14. Information stored in high-Q space: Role of high energy scattering

    SciTech Connect

    Egami, T.; Dmowski, W.; Billinge, S. J. L.; Kycia, S.; Eberhardt, A. S.

    1997-07-01

    Much of crystallographic diffraction measurements are focused on obtaining information with Q (=4{pi} sin {theta}/{lambda}) below 17 A{sup -1} or d>0.35 A, with the implicit assumption that no useful information is stored in the Q space above. However, this assumption is valid only with respect to the periodic lattice structure. Actually, high-Q space is full of information on the local atomic structure that could be of major importance in some cases. We discuss high energy x-ray or neutron scattering as the methods of obtaining the data from the high-Q space, and the atomic pair-distribution function (PDF) analysis as the means of extracting information from such data. Preliminary data of our recent high-energy x-ray scattering measurement on a MX compound are shown for which this type of analysis is likely to play a significant role in understanding the properties.

  15. Low-energy electron scattering from DNA including structural water and base-pair irregularities

    SciTech Connect

    Caron, Laurent; Sanche, Leon; Tonzani, Stefano; Greene, Chris H.

    2009-07-15

    Elastic scattering of low-energy (0-13 eV) electrons from more realistic models of a DNA base-pair decamer is studied using multiple-scattering theory and T matrices obtained from ab initio R-matrix calculations. The models include two types of irregularities usually found in cellular DNA: base-pair mismatch and structural water molecules. Furthermore, we include in our calculation inelastic collisions. It is found that the basic interference patterns observed in the ideal and nonideal (i.e., more realistic) decamers are similar but have different amplitudes and are shifted in energy. Substantial inelastic losses, interestingly, cause pronounced local resonances, which could have an important influence in DNA strand breaks.

  16. Off-energy-shell p-p scattering at sub-Coulomb energies via the Trojan horse method

    SciTech Connect

    Tumino, A.; Spitaleri, C.; Rapisarda, G. G.; Cherubini, S.; Crucilla, V.; Gulino, M.; Cognata, M. La; Lamia, L.; Pizzone, R. G.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A.; Campajola, L.; Elekes, Z.; Fueloep, Z.; Gyuerky, G.; Kiss, G.; Somorjai, E.; Gialanella, L.; Ordine, A.

    2008-12-15

    Two-proton scattering at sub-Coulomb energies has been measured indirectly via the Trojan horse method applied to the p + d{yields}p + p + n reaction to investigate off-energy shell effects for scattering processes. The three-body experiment was performed at 5 and 4.7 MeV corresponding to a p-p relative energy ranging from 80 to 670 keV. The free p-p cross section exhibits a deep minimum right within this relative energy region due to Coulomb plus nuclear destructive interference. No minimum occurs instead in the Trojan horse p-p cross section, which was extracted by employing a simple plane-wave impulse approximation. A detailed formalism was developed to build up the expression of the theoretical half-off-shell p-p cross section. Its behavior agrees with the Trojan horse data and in turn formally fits the n-n, n-p, and nuclear p-p cross sections given the fact that in its expression the Coulomb amplitude is negligible with respect to the nuclear one. These results confirm the Trojan horse suppression of the Coulomb amplitude for scattering due to the off-shell character of the process.

  17. Internal spin structure of the proton from high energy polarized e-p scattering

    SciTech Connect

    Hughes, V.W.; Baum, G.; Bergstroem, M.R.

    1981-02-01

    A review is given of experimental knowledge of the spin dependent structure functions of the proton, which is based on inclusive high energy scattering of longitudinal polarized electrons by longitudinally polarized protons in both the deep inelastic and resonance regions, and includes preliminary results from our most recent SLAC experiment. Implications for scaling, sum rules, models of proton structure, and the hyperfine structure interval in hydrogen are given. Possible future directions of research are indicated.

  18. Addition Laws for Intensities of Radiation Emerging from Scattering Atmospheres Containing Energy Sources

    NASA Astrophysics Data System (ADS)

    Nikoghossian, A. G.; Kapanadze, N. G.

    2016-03-01

    A group theoretical approach is developed for solving astrophysical radiative transfer problems described in a previous series of papers. Addition laws for observed radiative intensities are derived for the case in which atmospheres not only absorb and scatter radiation incident on them, but radiate themselves because of energy sources contained within them. As an illustration of the application of these laws, several special radiative transfer problems which we believe are of practical interest are discussed.

  19. Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures

    PubMed Central

    2012-01-01

    The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 − xInxNyAs1 − y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration of 32%. Micro-Raman measurements have been carried out using 532 and 758 nm lines of diode lasers, and the 1064 nm line of the Nd-YAG laser has been used for Fourier transform-Raman scattering measurements. Raman scattering measurements with different excitation sources have revealed that the excitation energy is the decisive mechanism on the nature of the Raman scattering spectrum. When the excitation energy is close to the electronic band gap energy of any constituent semiconductor materials in the sample, electronic transition dominates the spectrum, leading to a very broad peak. In the condition that the excitation energy is much higher than the band gap energy, only vibrational modes contribute to the Raman scattering spectrum of the samples. Line shapes of the Raman scattering spectrum with the 785 and 1064 nm lines of lasers have been observed to be very broad peaks, whose absolute peak energy values are in good agreement with the ones obtained from photoluminescence measurements. On the other hand, Raman scattering spectrum with the 532 nm line has exhibited only vibrational modes. As a complementary tool of Raman scattering measurements with the excitation source of 532 nm, which shows weak vibrational transitions, attenuated total reflectance infrared spectroscopy has been also carried out. The results exhibited that the nature of the Raman scattering spectrum is strongly excitation energy-dependent, and with suitable excitation energy, electronic and/or vibrational transitions can be investigated. PMID:23190628

  20. A scatter correction method for contrast-enhanced dual-energy digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Lu, Yihuan; Peng, Boyu; Lau, Beverly A.; Hu, Yue-Houng; Scaduto, David A.; Zhao, Wei; Gindi, Gene

    2015-08-01

    Contrast-enhanced dual energy digital breast tomosynthesis (CE-DE-DBT) is designed to image iodinated masses while suppressing breast anatomical background. Scatter is a problem, especially for high energy acquisition, in that it causes severe cupping artifact and iodine quantitation errors. We propose a patient specific scatter correction (SC) algorithm for CE-DE-DBT. The empirical algorithm works by interpolating scatter data outside the breast shadow into an estimate within the breast shadow. The interpolated estimate is further improved by operations that use an easily obtainable (from phantoms) table of scatter-to-primary-ratios (SPR)—a single SPR value for each breast thickness and acquisition angle. We validated our SC algorithm for two breast emulating phantoms by comparing SPR from our SC algorithm to that measured using a beam-passing pinhole array plate. The error in our SC computed SPR, averaged over acquisition angle and image location, was about 5%, with slightly worse errors for thicker phantoms. The SC projection data, reconstructed using OS-SART, showed a large degree of decupping. We also observed that SC removed the dependence of iodine quantitation on phantom thickness. We applied the SC algorithm to a CE-DE-mammographic patient image with a biopsy confirmed tumor at the breast periphery. In the image without SC, the contrast enhanced tumor was masked by the cupping artifact. With our SC, the tumor was easily visible. An interpolation-based SC was proposed by (Siewerdsen et al 2006 Med. Phys. 33 187-97) for cone-beam CT (CBCT), but our algorithm and application differ in several respects. Other relevant SC techniques include Monte-Carlo and convolution-based methods for CBCT, storage of a precomputed library of scatter maps for DBT, and patient acquisition with a beam-passing pinhole array for breast CT. Our SC algorithm can be accomplished in clinically acceptable times, requires no additional imaging hardware or extra patient dose and is

  1. Elastic scattering of 17O+208Pb at energies near the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Torresi, D.; Strano, E.; Mazzocco, M.; Boiano, A.; Boiano, C.; Di Meo, P.; La Commara, M.; Manea, C.; Nicoletto, M.; Grebosz, J.; Guglielmetti, A.; Molini, P.; Parascandolo, C.; Pierroutsakou, D.; Signorini, C.; Soramel, F.; Toniolo, N.; Filipescu, D.; Gheorghe, A.; Glodariu, T.; Jeong, S.; Kim, Y. H.; Lay, J. A.; Miyatake, H.; Pakou, A.; Sgouros, O.; Soukeras, V.; Stroe, L.; Vitturi, A.; Watanabe, Y.; Zerva, K.

    2016-05-01

    Within the frame of the commissioning of a new experimental apparatus EXPADES we undertook the measurement of the elastic scattering angular distribution for the system 17O+208Pb at energy around the Coulomb barrier. The reaction dynamics induced by loosely bound Radioactive Ion Beams is currently being extensively studied [4]. In particular the study of the elastic scattering process allows to obtain direct information on the total reaction cross section of the exotic nuclei. In order to understand the effect of the low binding energy on the reaction mechanism it is important to compare radioactive weakly bound nuclei with stable strongly-bound nuclei. In this framework the study of the 17O+208Pb elastic scattering can be considered to be complementary to a previous measurement of the total reaction cross section for the system 17F+208Pb at energies of 86, 90.4 MeV [5, 6]. The data will be compared with those obtained for the neighboring systems 16,18O+208Pb and others available in literature.

  2. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S.; Techert, Simone; Strocov, Vladimir N.; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

  3. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering.

    PubMed

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S; Techert, Simone; Strocov, Vladimir N; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future. PMID:26821751

  4. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering

    PubMed Central

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S.; Techert, Simone; Strocov, Vladimir N.; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future. PMID:26821751

  5. Teasing apart the effects of seed size and energy content on rodent scatter-hoarding behavior.

    PubMed

    Wang, Bo; Yang, Xiaolan

    2014-01-01

    Scatter-hoarding rodents are known to play a crucial role in the seed dispersal of many plant species. Numerous studies have indicated that both seed size and the energy content of seeds can affect rodent foraging behavior. However, seed size is usually associated with energy content per seed, making it difficult to isolate how seed size and energy affect rodent foraging preferences. This study used 99 treatments of artificial seeds (11 seed sizes×9 levels of energy content) to tease apart the effect of seed size and energy content on rodent seed-caching behavior. Both seed traits showed significant effects, but their details depended on the stage of the rodent foraging process. Seeds with higher energy content were harvested more rapidly while seed size only had a modest effect on harvest rate. However, after harvesting, seed size showed a much stronger effect on rodent foraging behavior. Rodents' choice of which seeds to remove and cache, as well as seed dispersal distance, seemed to reflect an optimal seed size. Our findings could be adapted in future studies to gain a better understanding of scatter-hoarding rodent foraging behavior, and the co-evolutionary dynamics between plant seed production and seed dispersers. PMID:25350369

  6. Cross sections for medium energy He ions scattered from Hf and Au atoms

    NASA Astrophysics Data System (ADS)

    Nishimura, Tomoaki; Mitsuhara, Kei; Visikovskiy, Anton; Kido, Yoshiaki

    2012-06-01

    The elastic scattering cross sections for medium energy He ions incident on Ni, Hf and Au atoms were measured precisely using a toroidal electrostatic analyzer. We prepared the targets of Ni(˜1 nm)/HfO2(1.5 nm)/Si(0 0 1) and Ni(˜1 nm)/Au(˜0.5 nm)/Si(1 1 1) and performed in situ ion scattering measurement under ultrahigh vacuum condition. The absolute amounts of Ni, Hf and Au were determined by Rutherford backscattering using 1.5 MeV He ions at a scattering angle of 150°. The scattering cross sections for Hf and Au were normalized by those for Ni to avoid the ambiguities of the number of incident particles, solid angle subtended by a detector, detection efficiency and the He+ fractions for the emerging He ions from the surfaces. The results obtained are compared with the simple Lee-Hart formula and the calculated values using the Molière and ZBL potentials and the potentials derived from the Hartree-Fock-Slater wave functions.

  7. Energy deposition model based on electron scattering cross section data from water molecules

    NASA Astrophysics Data System (ADS)

    Muñoz, A.; Oiler, J. C.; Blanco, F.; Gorfinkiel, J. D.; Limão-Vieira, P.; Maira-Vidal, A.; Borge, M. J. G.; Tengblad, O.; Huerga, C.; Téllez, M.; García, G.

    2008-10-01

    A complete set of electrons scattering cross sections by water molecules over a broad energy range, from the me V to the Me V ranges, is presented in this study. These data have been obtained by combining experiments and calculations and cover most relevant processes, both elastic and inelastic, which can take place in the considered energy range. A new Monte Carlo simulation programme has been developed using as input parameter these cross sectional data as well as experimental energy loss spectra. The simulation procedure has been applied to obtain electron tracks and energy deposition plots in water when irradiated by a Ru-106 plaque as those used for brachyteraphy of ocular tumours. Finally, the low energy electron tracks provided by the present model have been compared with those obtained with other codes available in the literature

  8. Low-energy theorems for nucleon-nucleon scattering at Mπ=450 MeV

    NASA Astrophysics Data System (ADS)

    Baru, V.; Epelbaum, E.; Filin, A. A.

    2016-07-01

    We apply the low-energy theorems to analyze the recent lattice QCD results for the two-nucleon system at a pion mass of Mπ≃450 MeV obtained by the NPLQCD Collaboration. We find that the binding energies of the deuteron and dineutron are inconsistent with the low-energy behavior of the corresponding phase shifts within the quoted uncertainties and vice versa. Using the binding energies of the deuteron and dineutron as input, we employ the low-energy theorems to predict the phase shifts and extract the scattering length and the effective range in the S31 and S10 channels. Our results for these quantities are consistent with those obtained by the NPLQCD Collaboration from effective field theory analyses but are in conflict with their determination based on the effective-range approximation.

  9. Exploring a direct measurement of quark energy loss using semi-inclusive deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Peña, C.; Brooks, W.; Hakobyan, H.; Arratia, M.

    2012-02-01

    This work consists of an evaluation of the feasibility of a direct extraction of quark energy loss from the E02-104 experiment π+ data and using semi-inclusive Deep Inelastic Scattering (DIS). The method is based on a shape analysis of the pion energy spectrum, coupled with a GENIE simulation which includes an hadronic cascade model in nuclei. The pion energy spectrum from different nuclei such as C, Fe, and Pb is compared to that of deuterium in order to find a simple energy shift, which is predicted by BDMPS if the parton energy is high enough that the medium length L is smaller than a certain critical length Lc. GENIE is used to rule out hadronic interaction effects which could also explain the same behavior observed in data.

  10. Energy calibration of a high-resolution inelastic x-ray scattering spectrometer.

    PubMed

    Verbeni, Roberto; D'Astuto, Matteo; Krisch, Michael; Lorenzen, Maren; Mermet, Alain; Monaco, Giulio; Requardt, Herwig; Sette, Francesco

    2008-08-01

    The energy scale of a triple-axis x-ray spectrometer with meV energy resolution based on perfect silicon crystal optics is calibrated, utilizing the most recent determination of the silicon lattice parameter and its thermal expansion coefficient and recording the dispersion of longitudinal acoustic and optical phonons in a diamond single crystal and the molecular vibration mode in liquid nitrogen. Comparison of the x-ray results with previous inelastic neutron and Raman scattering results as well as with ab initio phonon dispersion calculations yields an overall agreement better than 2%. PMID:19044359

  11. Energy calibration of a high-resolution inelastic x-ray scattering spectrometer

    SciTech Connect

    Verbeni, Roberto; D'Astuto, Matteo; Krisch, Michael; Lorenzen, Maren; Mermet, Alain; Monaco, Giulio; Requardt, Herwig; Sette, Francesco

    2008-08-15

    The energy scale of a triple-axis x-ray spectrometer with meV energy resolution based on perfect silicon crystal optics is calibrated, utilizing the most recent determination of the silicon lattice parameter and its thermal expansion coefficient and recording the dispersion of longitudinal acoustic and optical phonons in a diamond single crystal and the molecular vibration mode in liquid nitrogen. Comparison of the x-ray results with previous inelastic neutron and Raman scattering results as well as with ab initio phonon dispersion calculations yields an overall agreement better than 2%.

  12. Nucleon scattering from very light nuclei: Intermediate energy expansions for transition potentials and breakup processes

    SciTech Connect

    Elster, C.; Gloeckle, W.

    1997-03-01

    Transition potentials for elastic p-d scattering and the coupled processes p+{sup 3}He {r_arrow} p+{sup 3}He and n+{sup 3}He {r_arrow} d+d are derived in the Faddeev-Yakubovsky framework with special emphasis on leading order terms, which are expected to be valid at intermediate energies. In addition, equations for the fragmentations {sup 3}He(p,ppp)n and {sup 3}He(p,pp)d are derived within the same framework. Again leading order terms for intermediate energies are considered. {copyright} {ital 1997} {ital The American Physical Society}

  13. Elastic scattering for the system {sup 6}Li+p at near barrier energies with MAGNEX

    SciTech Connect

    Soukeras, V.; Pakou, A.; Sgouros, O.; Cappuzzello, F.; Bondi, M.; Nicolosi, D.; Acosta, L.; Marquinez-Duran, G.; Martel, I.; Agodi, C.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Di Pietro, A.; Fernández-García, J. P.; Figuera, P.; Fisichella, M.; Alamanos, N.; De Napoli, M.; Foti, A.; and others

    2015-02-24

    Elastic scattering measurements have been performed for the {sup 6}Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼2{sup 0} and 12{sup 0} in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies.

  14. QED radiative corrections to low-energy Møller and Bhabha scattering

    NASA Astrophysics Data System (ADS)

    Epstein, Charles S.; Milner, Richard G.

    2016-08-01

    We present a treatment of the next-to-leading-order radiative corrections to unpolarized Møller and Bhabha scattering without resorting to ultrarelativistic approximations. We extend existing soft-photon radiative corrections with new hard-photon bremsstrahlung calculations so that the effect of photon emission is taken into account for any photon energy. This formulation is intended for application in the OLYMPUS experiment and the upcoming DarkLight experiment but is applicable to a broad range of experiments at energies where QED is a sufficient description.

  15. Energy loss and small angle scattering of swift protons passing through liquid ethanol target

    NASA Astrophysics Data System (ADS)

    Kaneda, M.; Sato, S.; Shimizu, M.; He, Z.; Ishii, K.; Tsuchida, H.; Itoh, A.

    2007-03-01

    We have measured energy and angular distributions of fast protons passing through an ethanol liquid jet target. By applying the Moliére's theory of multiple scattering, we reproduced successfully our experimental results of energy and angular distributions and found that the Moliére's theory is useful for the prediction of energetic proton and heavy ion deflection in liquid materials. Moreover, we compared stopping powers obtained from our experiment with SRIM2003 and found an about 10% discrepancy between them. The present method can become a powerful tool for the measurement of particle stopping in liquids and the other collision interactions.

  16. A phenomenological study of photon production in low energy neutrino nucleon scattering

    SciTech Connect

    Jenkins, James P; Goldman, Terry J

    2009-01-01

    Low energy photon production is an important background to many current and future precision neutrino experiments. We present a phenomenological study of t-channel radiative corrections to neutral current neutrino nucleus scattering. After introducing the relevant processes and phenomenological coupling constants, we will explore the derived energy and angular distributions as well as total cross-section predictions along with their estimated uncertainties. This is supplemented throughout with comments on possible experimental signatures and implications. We conclude with a general discussion of the analysis in the context of complimentary methodologies. This is based on a talk presented at the DPF 2009 meeting in Detroit MI.

  17. Elastic scattering of {sup 9}Li on {sup 208}Pb at energies around the Coulomb barrier

    SciTech Connect

    Cubero, M.; Fernandez-Garcia, J. P.; Alvarez, M. A. G.; Lay, J. A.; Moro, A. M.; Acosta, L.; Martel, I.; Sanchez-Benitez, A. M.; Alcorta, M.; Borge, M. J. G.; Tengblad, O.; Buchmann, L.; Shotter, A.; Walden, P.; Diget, D. G.; Fulton, B.; Fynbo, H. O. U.; Galaviz, D.; Gomez-Camacho, J.; Mukha, I.

    2011-10-28

    We have studied the dynamical effects of the halo structure of {sup 11}Li on the scattering on heavy targets at energies around the Coulomb barrier. This experiment was performed at ISAC-II at TRIUMF with a world record in production of the post-accelerated {sup 11}Li beam. As part of this study we report here on the first measurement of the elastic cross section of the core nucleus, i.e. {sup 9}Li on {sup 208}Pb, at energies around the Coulomb barrier. A preliminary optical model analysis has been performed in order to extract a global optical potential to describe the measured angular distributions.

  18. Ultra-High Energy Neutrino-Nucleon Scattering and Parton Distributions at Small x

    SciTech Connect

    Henley, Ernest M.; Jalilian-Marian, Jamal

    2006-11-17

    The cross section for ultra-high energy neutrino-nucleon scattering is very sensitive to the parton distributions at very small values of Bjorken x (x {<=} 10-4). We numerically investigate the effects of modifying the behavior of the gluon distribution function at very small x in the DGLAP evolution equation. We then use the Color Glass Condensate formalism to calculate the neutrino-nucleon cross section at ultra-high energies and compare the result with those based on modification of DGLAP evolution equation.

  19. A low and hyperthemal energy UHV ion beamline for surface scattering spectroscopies

    NASA Astrophysics Data System (ADS)

    Ray, M. P.; Moody, S. A.; Sosolik, C. E.

    2006-03-01

    We are using a differentially pumped beamline to provide well- collimated, monoenergetic beams of noble gas and alkali-metal ions that range in energy from <10eV to 10keV. These ion beams are scattered from a surface (e.g. Cu(001)) to study charge transfer effects, energy loss, and the excitation of surface phonons and excitons. The ion beam is focused into a UHV scattering chamber that possesses capabilities for studying and characterizing samples using LEED, Auger spectroscopy, and a Kelvin probe for work function measurements. Recent additions to this setup include replacing diffusion pumps with turbo pumps as well as the addition of a fast entry load-lock sample exchange system. Our current research is focused on developing a source to produce an ion beam of C60 as well as studying charge transfer and energy loss effects at the low and hyperthermal energy range. Also, we are investigating chemicurrents associated with Schottky diodes in this energy regime.

  20. Optical depth of the Universe to ultrahigh energy cosmic ray scattering in the magnetized large scale structure

    NASA Astrophysics Data System (ADS)

    Kotera, Kumiko; Lemoine, Martin

    2008-06-01

    This paper provides an analytical description of the transport of ultrahigh energy cosmic rays in an inhomogeneously magnetized intergalactic medium. The latter is modeled as a collection of magnetized scattering centers, such as radio cocoons, magnetized galactic winds, clusters or magnetized filaments of large scale structure, with negligible magnetic fields in between. Magnetic deflection is no longer a continuous process, it is rather dominated by scattering events. We study the interaction between high-energy cosmic rays and the scattering agents. We then compute the optical depth of the Universe to cosmic ray scattering and discuss the phenomenological consequences for various source scenarios. For typical parameters of the scattering centers, the optical depth is greater than unity at 5×1019eV, but the total angular deflection is smaller than unity. One important consequence of this scenario is the possibility that the last scattering center encountered by a cosmic ray be mistaken with the source of this cosmic ray. In particular, we suggest that part of the correlation recently reported by the Pierre Auger Observatory may be affected by such delusion: this experiment may be observing in part the last scattering surface of ultrahigh energy cosmic rays rather than their source population. Since the optical depth falls rapidly with increasing energy, one should probe the arrival directions of the highest energy events beyond 1020eV on an event by event basis to circumvent this effect.

  1. Optical depth of the Universe to ultrahigh energy cosmic ray scattering in the magnetized large scale structure

    SciTech Connect

    Kotera, Kumiko; Lemoine, Martin

    2008-06-15

    This paper provides an analytical description of the transport of ultrahigh energy cosmic rays in an inhomogeneously magnetized intergalactic medium. The latter is modeled as a collection of magnetized scattering centers, such as radio cocoons, magnetized galactic winds, clusters or magnetized filaments of large scale structure, with negligible magnetic fields in between. Magnetic deflection is no longer a continuous process, it is rather dominated by scattering events. We study the interaction between high-energy cosmic rays and the scattering agents. We then compute the optical depth of the Universe to cosmic ray scattering and discuss the phenomenological consequences for various source scenarios. For typical parameters of the scattering centers, the optical depth is greater than unity at 5x10{sup 19} eV, but the total angular deflection is smaller than unity. One important consequence of this scenario is the possibility that the last scattering center encountered by a cosmic ray be mistaken with the source of this cosmic ray. In particular, we suggest that part of the correlation recently reported by the Pierre Auger Observatory may be affected by such delusion: this experiment may be observing in part the last scattering surface of ultrahigh energy cosmic rays rather than their source population. Since the optical depth falls rapidly with increasing energy, one should probe the arrival directions of the highest energy events beyond 10{sup 20} eV on an event by event basis to circumvent this effect.

  2. A novel scatter separation method for multi-energy x-ray imaging

    NASA Astrophysics Data System (ADS)

    Sossin, A.; Rebuffel, V.; Tabary, J.; Létang, J. M.; Freud, N.; Verger, L.

    2016-06-01

    X-ray imaging coupled with recently emerged energy-resolved photon counting detectors provides the ability to differentiate material components and to estimate their respective thicknesses. However, such techniques require highly accurate images. The presence of scattered radiation leads to a loss of spatial contrast and, more importantly, a bias in radiographic material imaging and artefacts in computed tomography (CT). The aim of the present study was to introduce and evaluate a partial attenuation spectral scatter separation approach (PASSSA) adapted for multi-energy imaging. This evaluation was carried out with the aid of numerical simulations provided by an internal simulation tool, Sindbad-SFFD. A simplified numerical thorax phantom placed in a CT geometry was used. The attenuation images and CT slices obtained from corrected data showed a remarkable increase in local contrast and internal structure detectability when compared to uncorrected images. Scatter induced bias was also substantially decreased. In terms of quantitative performance, the developed approach proved to be quite accurate as well. The average normalized root-mean-square error between the uncorrected projections and the reference primary projections was around 23%. The application of PASSSA reduced this error to around 5%. Finally, in terms of voxel value accuracy, an increase by a factor  >10 was observed for most inspected volumes-of-interest, when comparing the corrected and uncorrected total volumes.

  3. A novel scatter separation method for multi-energy x-ray imaging.

    PubMed

    Sossin, A; Rebuffel, V; Tabary, J; Létang, J M; Freud, N; Verger, L

    2016-06-21

    X-ray imaging coupled with recently emerged energy-resolved photon counting detectors provides the ability to differentiate material components and to estimate their respective thicknesses. However, such techniques require highly accurate images. The presence of scattered radiation leads to a loss of spatial contrast and, more importantly, a bias in radiographic material imaging and artefacts in computed tomography (CT). The aim of the present study was to introduce and evaluate a partial attenuation spectral scatter separation approach (PASSSA) adapted for multi-energy imaging. This evaluation was carried out with the aid of numerical simulations provided by an internal simulation tool, Sindbad-SFFD. A simplified numerical thorax phantom placed in a CT geometry was used. The attenuation images and CT slices obtained from corrected data showed a remarkable increase in local contrast and internal structure detectability when compared to uncorrected images. Scatter induced bias was also substantially decreased. In terms of quantitative performance, the developed approach proved to be quite accurate as well. The average normalized root-mean-square error between the uncorrected projections and the reference primary projections was around 23%. The application of PASSSA reduced this error to around 5%. Finally, in terms of voxel value accuracy, an increase by a factor  >10 was observed for most inspected volumes-of-interest, when comparing the corrected and uncorrected total volumes. PMID:27249312

  4. Low-energy elastic electron scattering from isobutanol and related alkyl amines

    NASA Astrophysics Data System (ADS)

    Fedus, Kamil; Navarro, C.; Hargreaves, L. R.; Khakoo, M. A.; Silva, F. M.; Bettega, M. H. F.; Winstead, C.; McKoy, V.

    2014-09-01

    Normalized experimental differential and integral cross sections for vibrationally elastic scattering of low-energy electrons from isobutanol (C4H9OH ) are presented. The differential cross sections are measured at incident energies from 1 to 100 eV and scattering angles from 5∘ to 130∘. These cross sections are compared to earlier experimental and theoretical results for isobutanol and n-butanol, as well as to results for smaller alcohols and for alkanes. Further comparisons are made with calculated cross sections for isobutylamine (C4H9NH2) and for smaller amines, including ethylamine (C2H5NH2), dimethylamine (CH3NHCH3), the two C3H7NH2 isomers n-propylamine and isopropylamine, and ethylene diamine (NH2C2H4NH2). The calculated cross sections are obtained using the Schwinger multichannel method. The comparisons illuminate the role of molecular structure in determining the angular distribution of resonantly scattered electrons.

  5. X-ray coherent scattering form factors of tissues, water and plastics using energy dispersion

    NASA Astrophysics Data System (ADS)

    King, B. W.; Landheer, K. A.; Johns, P. C.

    2011-07-01

    A key requirement for the development of the field of medical x-ray scatter imaging is accurate characterization of the differential scattering cross sections of tissues and phantom materials. The coherent x-ray scattering form factors of five tissues (fat, muscle, liver, kidney, and bone) obtained from butcher shops, four plastics (polyethylene, polystyrene, lexan (polycarbonate), nylon), and water have been measured using an energy-dispersive technique. The energy-dispersive technique has several improvements over traditional diffractometer measurements. Most notably, the form factor is measured on an absolute scale with no need for scaling factors. Form factors are reported in terms of the quantity x = λ-1sin (θ/2) over the range 0.363-9.25 nm-1. The coherent form factors of muscle, liver, and kidney resemble those of water, while fat has a narrower peak at lower x, and bone is more structured. The linear attenuation coefficients of the ten materials have also been measured over the range 30-110 keV and parameterized using the dual-material approach with the basis functions being the linear attenuation coefficients of polymethylmethacrylate and aluminum.

  6. Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

    NASA Astrophysics Data System (ADS)

    Toft-Petersen, Rasmus; Groitl, Felix; Kure, Mathias; Lim, Joshua; Čermák, Petr; Alimov, Svyatoslav; Wilpert, Thomas; Le, Manh Duc; Quintero-Castro, Diana; Niedermayer, Christof; Schneidewind, Astrid; Habicht, Klaus

    2016-09-01

    A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 θ -segments) each containing five vertically scattering analyzers (energy channels), which simultaneously probe an energy transfer range of 2 meV at the corresponding two scattering angles. The feasibility and strength of such a vertically scattering multiple energy analysis setup is clearly demonstrated. It is shown, that the energy resolution near the elastic line is comparable to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis)matching of the instrumental resolution ellipsoid to the excitation branch are clearly evident.

  7. Low-energy electron elastic scattering cross sections for excited Au and Pt atoms

    NASA Astrophysics Data System (ADS)

    Felfli, Zineb; Eure, Amanda R.; Msezane, Alfred Z.; Sokolovski, Dmitri

    2010-05-01

    Electron elastic total cross sections (TCSs) and differential cross sections (DCSs) in both impact energy and scattering angle for the excited Au and Pt atoms are calculated in the electron impact energy range 0 ⩽ E ⩽ 4.0 eV. The cross sections are found to be characterized by very sharp long-lived resonances whose positions are identified with the binding energies of the excited anions formed during the collisions. The recent novel Regge-pole methodology wherein is embedded through the Mulholland formula the electron-electron correlations is used together with a Thomas-Fermi type potential incorporating the crucial core-polarization interaction for the calculations of the TCSs. The DCSs are evaluated using a partial wave expansion. The Ramsauer-Townsend minima, the shape resonances and the binding energies of the excited Au - and Pt - anions are extracted from the cross sections, while the critical minima are determined from the DCSs.

  8. Direct observation of space charge dynamics by picosecond low-energy electron scattering

    NASA Astrophysics Data System (ADS)

    Cirelli, C.; Hengsberger, M.; Dolocan, A.; Over, H.; Osterwalder, J.; Greber, T.

    2009-01-01

    The transient electric field governing the dynamics of space charge is investigated by time- and energy-resolved low-energy electron scattering. The space charge above a copper target is produced by high-intensity femtosecond laser pulses. The pump-probe experiment has a measured temporal resolution of better than 35 ps at 55 eV probe electron energy. The probe electron acceleration due to space charge is reproduced within a 3-dimensional non-relativistic model, which determines an effective number of electrons in the space charge cloud and its initial diameter. Comparison of the simulations with the experiments indicates a Coulomb explosion, which is consistent with transients in the order of 1 ns, the terminal kinetic energy of the cloud and the thermoemission currents predicted by the Richardson-Dushman formula.

  9. Nuclear inelastic scattering of heme proteins: from iron ligand vibrations to low energy protein modes

    NASA Astrophysics Data System (ADS)

    Moeser, Beate; Janoschka, Adam; Wolny, Juliusz A.; Filipov, Igor; Chumakov, Aleksandr I.; Walker, F. Ann; Schünemann, Volker

    2012-03-01

    The binding of the signal molecule nitric oxide (NO) to the NO transporter protein Nitrophorin 2 (NP2) from the bloodsucking insect Rhodnius prolixus has been characterized by Mössbauer spectroscopy as well as nuclear forward scattering (NFS) and nuclear inelastic scattering (NIS). A striking feature of the vibrational spectrum obtained from NP2-NO is a vibration at 594 cm - 1. This mode is assigned to a Fe-NO stretching mode via simulation of the NIS data by density functional theory (DFT) coupled with molecular mechanics (MM) methods. At frequencies below 100 cm - 1 collective motions like heme doming occur which could explain spectroscopic features observed by NIS at these low energies.

  10. Experimental and simulated validation of the energy dependence of saturation thickness of multiple scattered gamma rays

    NASA Astrophysics Data System (ADS)

    Eshwarappa, Kunabevu Mallikarjunappa; Kiran, Kiggal Udayashankar; Ravindraswami, Kalladka; Somashekarappa, Hiriyur Mallaiah

    2014-11-01

    Saturation thickness for multiple scattering gamma rays from multiple sources has been measured experimentally and simulated using the Monte Carlo N-Particle (MCNP) Code. Experimental measurements were performed using a collimated beam of gamma-rays from 57Co, 203Hg, 133Ba, 22Na, 137Cs, 65Zn and 60Co sources. The gamma rays were directed at rectangular aluminium targets of varying thickness. A NaI (Tl) scintillation detector placed at a backscattering angle of 180° was used to detect the scattered photons. The measured and calculated saturation thickness increases with increasing energy of incident gamma-rays. Experimental and simulated values are compared and are in good agreement.

  11. Quasielastic neutron scattering experiments including activation energies and mathematical modeling of methyl halide dynamics

    NASA Astrophysics Data System (ADS)

    Kirstein, O.; Prager, M.; Grimm, H.; Buchsteiner, A.; Wischnewski, A.

    2007-09-01

    Quasielastic neutron scattering experiments were carried out using the multichopper time-of-flight spectrometer V3 at the Hahn-Meitner Institut, Germany and the backscattering spectrometer at Forschungszentrum Jülich, Germany. Activation energies for CH3X, X =F, Cl, Br, and I, were obtained. In combination with results from previous inelastic neutron scattering experiments the data were taken to describe the dynamics of the halides in terms of two different models, the single particle model and the coupling model. Coupled motions of methyl groups seem to explain the dynamics of the methyl fluoride and chloride; however, the coupling vanishes with the increase of the mass of the halide atom in CH3Br and CH3I.

  12. Coupling of Multiple Coulomb Scattering with Energy Loss and Straggling in HZETRN

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Wilson, John W.; Walker, Steven A.; Tweed, John

    2007-01-01

    The new version of the HZETRN deterministic transport code based on Green's function methods, and the incorporation of ground-based laboratory boundary conditions, has lead to the development of analytical and numerical procedures to include off-axis dispersion of primary ion beams due to small-angle multiple Coulomb scattering. In this paper we present the theoretical formulation and computational procedures to compute ion beam broadening and a methodology towards achieving a self-consistent approach to coupling multiple scattering interactions with ionization energy loss and straggling. Our initial benchmark case is a 60 MeV proton beam on muscle tissue, for which we can compare various attributes of beam broadening with Monte Carlo simulations reported in the open literature.

  13. K--Nucleus Elastic Scattering at IntermediateEnergies in the Isobar-Doorway Model

    NASA Astrophysics Data System (ADS)

    Toyama, F. M.

    1983-11-01

    The differential cross sections for the K--nucleus elastic scattering at about PK = 800 MeV/c are calculated in the phenomenological isobar-doorway model. The many-body corrections on Y* resonances in nuclei are represented by the resonance energy shift Δ E and width-modification factor β. The parametrizations given by Gopal et al. are used for the resonance amplitudes. The effects of Δ E and β on the cross sections are investigated in detail. The results are compared with the available experimental data for the K- elastic scattering on 12C and 40Ca at PK = 800 MeV/c. The calculated cross sections are in good agreement with the data. However, the cross sections are not very sensitive to Δ E and β.

  14. Importance of nonresonant scattering in low-energy dissociative electron attachment to molecular hydrogen.

    PubMed

    Rabli, Djamal; Morrison, Michael A

    2006-07-01

    A central premise of nearly all theories of dissociative electron attachment is that this process is resonance driven. Neglect of nonresonant scattering, although appropriate for electron-molecule systems with narrow (long-lived) resonances, is problematic for the e-H2 system, which has one of the broadest known resonances. Using the nonadiabatic phase-matrix method we have found that at energies from threshold to 6 eV contributions from nonresonant scattering to cross sections to dissociative attachment to in its ground vibrational and electronic state exceed 60%. Comparison of theoretical and experimental cross sections argue strongly for further efforts to resolve the considerable remaining discrepancies over this most elementary rearrangement process. PMID:16907375

  15. The influence of inner-shell electron promotion on charge exchange processes in low energy ion scattering from surfaces

    NASA Astrophysics Data System (ADS)

    Ting Li; MacDonald, R. J.

    1997-11-01

    The influence of inner-shell electron promotion on charge exchange in low energy (1-7 keV) Ne + ions scattered from the Cu (1 0 0), Ni (1 0 0) and Fe (1 1 0) surfaces has been studied systematically. The yield of Ne + ion scattered from these surfaces has been measured as a function of incident ion energy under various scattering geometries. The relative Ne + ion fraction, which is proportional to the normalised ion yield divided by the differential scattering cross section, is studied and an empirical formula for relative ion fraction has been extracted. The formula combines the charge exchanges along the incoming trajectory, during the close encounter, and along the outgoing trajectory into one simple expression. It can be concluded that inner-shell electron excitations during close encounters contribute significantly to the charge exchange in the scattering systems studied in this work.

  16. Transmission coefficient for a point scatterer at specific energies is affected by the presence of the scatterer but independent of the scatterer's characteristics

    SciTech Connect

    Granot, Er'el

    2005-01-15

    We calculate the exact transmission coefficients of a quantum wire in the presence of a single point defect at the wire's cutoff frequencies. We show that at these frequencies while the conductance pattern (i.e., the scattering) is strongly affected by the presence of the defect, the pattern is totally independent of the defect's characteristics (i.e., the defect that caused the scattering cannot be identified from that pattern). The change in the conduction pattern can cause universal attraction and/or repulsion forces between two parallel conducting wires.

  17. Electron-atom superelastic scattering in magnesium at millielectron volt energies.

    PubMed

    Baynard, T; Reber, A C; Niedziela, R F; Darveau, S A; Prutzman, B; Berry, R S

    2007-12-13

    The energy dependence of superelastic scattering is measured for electrons on Mg(3(1)P) from threshold to 270 meV with a novel technique. The method uses photoelectrons produced by a narrow bandwidth laser as an approximately monoenergetic incident electron source to collide with excited atoms. Measurements are made at energies as low as 1.5 meV with a resolution of 1 meV near threshold. An efficient magnetic-bottle time-of-flight electron spectrometer allows for the simultaneous measurement of multiple scattering channels. Above-threshold ionization is also observed. The measured energy dependence for transitions from the 3(1)P state to both the 3(3)P and 3(1)S are found to be inversely proportional to the energy from 10 to 270 meV. Below 10 meV, the dependencies are different, with the 3(3)P transition having an E(-1/2) dependence and the 3(1)S channel retaining an E(-1) dependence. PMID:17985853

  18. High energy proton-proton elastic scattering at the Large Hadron Collider and nucleon structure

    NASA Astrophysics Data System (ADS)

    Luddy, Richard Joseph

    To gain insight into the structure of the nucleon, we pursue the development of the phenomenological model of Islam et al. (IIFS model) for high energy elastic pp and p¯p scattering. We determine the energy dependence of the parameters of the IIFS model using the available elastic differential cross section data from SPS Collider and Tevatron and the known asymptotic behavior of sigmatot (s) and rho(s) from dispersion relation calculations and more recent analyses of Cudell et al. (COMPETE Collaboration). Next, we incorporate a high energy elastic valence quark-quark scattering amplitude into the model based on BFKL pomeron to describe small impact parameter (large | t|) pp collisions. Finally, we predict the pp elastic differential cross section at the unprecedented c.m. energy of s = 14.0 TeV at the Large Hadron Collider (LHC). This prediction assumes crucial significance---because of an approved experiment at LHC: TOTal and Elastic Measurement (TOTEM). The TOTEM group plans to measure pp elastic dsigma/dt at 14.0 TeV all the way from momentum transfer |t| = 0 to |t| ≃ 10 GeV 2. Their measurement will stringently test not only the diffraction and o-exchange descriptions of the original IIFS model, but also the additional valence quark-quark scattering contribution that we find to be dominant for large |t|. Successful quantitative verification of the predicted dsigma/dt will mean that our picture of the nucleon with an outer cloud of qq¯ condensed ground state, an inner core of topological baryonic charge, and a still smaller core of massless valence quarks provides a realistic description of nucleon structure.

  19. An accurate method for energy spectrum reconstruction of Linac beams based on EPID measurements of scatter radiation

    NASA Astrophysics Data System (ADS)

    Juste, B.; Miró, R.; Verdú, G.; Santos, A.

    2014-06-01

    This work presents a methodology to reconstruct a Linac high energy photon spectrum beam. The method is based on EPID scatter images generated when the incident photon beam impinges onto a plastic block. The distribution of scatter radiation produced by this scattering object placed on the external EPID surface and centered at the beam field size was measured. The scatter distribution was also simulated for a series of monoenergetic identical geometry photon beams. Monte Carlo simulations were used to predict the scattered photons for monoenergetic photon beams at 92 different locations, with 0.5 cm increments and at 8.5 cm from the centre of the scattering material. Measurements were performed with the same geometry using a 6 MeV photon beam produced by the linear accelerator. A system of linear equations was generated to combine the polyenergetic EPID measurements with the monoenergetic simulation results. Regularization techniques were applied to solve the system for the incident photon spectrum. A linear matrix system, A×S=E, was developed to describe the scattering interactions and their relationship to the primary spectrum (S). A is the monoenergetic scatter matrix determined from the Monte Carlo simulations, S is the incident photon spectrum, and E represents the scatter distribution characterized by EPID measurement. Direct matrix inversion methods produce results that are not physically consistent due to errors inherent in the system, therefore Tikhonov regularization methods were applied to address the effects of these errors and to solve the system for obtaining a consistent bremsstrahlung spectrum.

  20. Low-energy extensions of the eikonal approximation to heavy-ion scattering

    SciTech Connect

    Aguiar, C.E.; Aguiar, C.E.; Zardi, F.; Vitturi, A.

    1997-09-01

    We discuss different schemes devised to extend the eikonal approximation to the regime of low bombarding energies (below 50 MeV per nucleon) in heavy-ion collisions. From one side we consider the first- and second-order corrections derived from Wallace{close_quote}s expansion. As an alternative approach we examine the procedure of accounting for the distortion of the eikonal straight-line trajectory by shifting the impact parameter to the corresponding classical turning point. The two methods are tested for different combinations of colliding systems and bombarding energies, by comparing the angular distributions they provide with the exact solution of the scattering problem. We find that the best results are obtained with the shifted trajectories, the Wallace expansion showing a slow convergence at low energies, in particular for heavy systems characterized by a strong Coulomb field. {copyright} {ital 1997} {ital The American Physical Society}

  1. Low-energy theorems for nucleon-nucleon scattering at unphysical pion masses

    NASA Astrophysics Data System (ADS)

    Baru, V.; Epelbaum, E.; Filin, A. A.; Gegelia, J.

    2015-07-01

    The longest-range part of the nuclear force from the one-pion exchange governs the energy dependence of the scattering amplitude in the near-threshold region and imposes correlations between the coefficients in the effective range expansion. These correlations may be regarded as low-energy theorems and are known to hold to a high accuracy in the neutron-proton 3S1 partial wave. We generalize the low-energy theorems to the case of unphysical pion masses and provide results for the correlations between the coefficients in the effective range expansion in this partial wave for pion masses up to Mπ˜400 MeV . We discuss the implications of our findings for the available and upcoming lattice-quantum-chromodynamics simulations of two-nucleon observables.

  2. Density functional theory for low-energy electron-molecule scattering

    NASA Astrophysics Data System (ADS)

    Burke, Kieron; Wasserman, Adam

    2004-09-01

    Time-dependent density functional theory (TDDFT) is becoming popular as an approach to time-dependent electronic problems[1]. In the weak field regime, TDDFT predicts electronic transition frequencies and optical spectra of atoms, molecules, clusters, and solids, with an accuracy comparable to high-level wavefunction calculations at a fraction of the computational cost[2]. For large systems, TDDFT is the method of choice. Given the importance of correlation effects in low-energy electron-molecule scattering, extracting scattering amplitudes from TDDFT appears desirable. I will review this background, and outline how this can be done[3]. Detailed results will be shown by Wasserman in another talk. [1] Time-Dependent Density Functional Theory, M.A.L. Marques and E.K.U. Gross, Annu. Rev. Phys. Chem. 55, 427 (2004). [2] Time-dependent density functional theory in quantum chemistry, F. Furche and K. Burke, to appear in 1st vol. of Annu. Rev. of Computational Chemistry (2004) [3] Electron-molecule scattering from time-dependent density functional theory A. Wasserman, N.T. Maitra, and K. Burke, submitted (see http:dft.rutgers.edu/pubs/publist.html).

  3. THE VERY HIGH ENERGY EMISSION FROM PULSARS: A CASE FOR INVERSE COMPTON SCATTERING

    SciTech Connect

    Lyutikov, Maxim; Otte, Nepomuk; McCann, Andrew

    2012-07-20

    The observations of gamma-ray emission from pulsars with the Fermi-LAT detector and the detection of the Crab pulsar with the VERITAS array of Cherenkov telescopes at energies above 100 GeV make it unlikely that curvature radiation is the main source of photons above GeV energies in the Crab and many other pulsars. We outline a model in which the broad UV-X-ray component and the very high energy {gamma}-ray emission of pulsars are explained within the synchrotron self-Compton framework. We argue that the bulk of the observed radiation is generated by the secondary plasma, which is produced in cascades in the outer gaps of the magnetosphere. We find that the inverse Compton (IC) scattering occurs in the Klein-Nishina regime, which favors synchrotron photons in the UV band as target field for the scattering process. The primary beam is accelerated in a modest electric field, with a field strength that is of the order of a few percent of the magnetic field near the light cylinder. Overall, for IC scattering occurring in the Klein-Nishina regime, the particle distribution in the gap does not evolve toward a stationary distribution and thus is intrinsically time-dependent. We point out that in a radiation reaction-limited regime of particle acceleration the gamma-ray luminosity L{sub {gamma}} scales linearly with the pulsar spin-down power E-dot , L{sub {gamma}}{proportional_to} E-dot , and not proportional to {radical}( E-dot ) as expected from potential-limited acceleration.

  4. Determination of energy windows for the triple energy window scatter correction method in I-131 on a Siemens SYMBIA gamma camera: a GATE simulation study

    NASA Astrophysics Data System (ADS)

    Lee, Young Sub; Kim, Jin Su; Kim, Kyeong Min; Moo Lim, Sang; Kim, Hee-Joung

    2015-01-01

    Image correction for scattered photons is important for the quantification of gamma-camera imaging using I-131. Many previous studies have addressed this issue but none have compared scattered photon fractions of I-131 with varying energy windows, to determine optimal main- and sub-energy windows for the implementation of TEW correction in I-131 imaging. We assessed the scattered photon fractions and determined the optimal main- and sub- energy windows for TEW in I-131 using a Siemens SYMBIA T2 SPECT/CT using a Monte Carlo method (GATE simulation). To validate the GATE simulation code, we compared the spatial resolutions obtained experimentally and from GATE simulation, for I-123 and Tc-99m. A high-energy general purpose (HE) collimator was used to assess the scattered photon fractions measured with the I-131 radioisotope placed at eight different field-of-view locations in a water phantom (diameter 16 cm, length 32 cm), and at the center in air. To implement the TEW (triple energy window) method, two different main-energy window widths (15 and 20%) and two different sub-energy window widths (3 and 5 keV) were used. The experimental measurement and simulation results exhibited a similar pattern with < 15% difference in spatial resolution with increasing distance. The I-131 scatter fraction with 15% of the main-energy window and 5 keV sub-energy windows was similar to the ``goldstandard'' scatter fraction. Main- and sub-energy window selection for the TEW correction in I-131 is important to avoid over- or under-correction in the scatter fraction. A 15% of main energy window with 5 keV sub-energy windows were found to be optimal for implementation of the TEW method in I-131. This result provides the optimal energy window for I-131 scintigraphy data and will aid the quantification of I-131 imaging.

  5. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun.

    1990-01-01

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  6. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun

    1990-12-31

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  7. Dual-energy digital mammography for calcification imaging: Scatter and nonuniformity corrections

    SciTech Connect

    Kappadath, S. Cheenu; Shaw, Chris C.

    2005-11-15

    Mammographic images of small calcifications, which are often the earliest signs of breast cancer, can be obscured by overlapping fibroglandular tissue. We have developed and implemented a dual-energy digital mammography (DEDM) technique for calcification imaging under full-field imaging conditions using a commercially available aSi:H/CsI:Tl flat-panel based digital mammography system. The low- and high-energy images were combined using a nonlinear mapping function to cancel the tissue structures and generate the dual-energy (DE) calcification images. The total entrance-skin exposure and mean-glandular dose from the low- and high-energy images were constrained so that they were similar to screening-examination levels. To evaluate the DE calcification image, we designed a phantom using calcium carbonate crystals to simulate calcifications of various sizes (212-425 {mu}m) overlaid with breast-tissue-equivalent material 5 cm thick with a continuously varying glandular-tissue ratio from 0% to 100%. We report on the effects of scatter radiation and nonuniformity in x-ray intensity and detector response on the DE calcification images. The nonuniformity was corrected by normalizing the low- and high-energy images with full-field reference images. Correction of scatter in the low- and high-energy images significantly reduced the background signal in the DE calcification image. Under the current implementation of DEDM, utilizing the mammography system and dose level tested, calcifications in the 300-355 {mu}m size range were clearly visible in DE calcification images. Calcification threshold sizes decreased to the 250-280 {mu}m size range when the visibility criteria were lowered to barely visible. Calcifications smaller than {approx}250 {mu}m were usually not visible in most cases. The visibility of calcifications with our DEDM imaging technique was limited by quantum noise, not system noise.

  8. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-07-01

    At high energies, the relevant degrees of freedom are Wilson lines - infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

  9. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-05-15

    At high energies, the relevant degrees of freedom are Wilson lines - infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

  10. Performances of a method for reconstructing the energy of neutrons detected by a double scattering spectrometer

    SciTech Connect

    Agnello, M.; Botta, E.; Bressani, T.; Calvo, D.; Gianotti, P.; Iazzi, F.; Lamberti, C.; Minetti, B. ); Balocco, E. )

    1992-10-01

    This paper reports on a neutron spectrometer based on the double scattering technique which has been designed and built at the Laboratorio Tecnologico of INFN - Turin (Italy) for Cold Fusion experiments. The operating principle for the reconstruction of the energy can be applied to various fields (neutron emission from sources, fission and fusion) and is described together with the performed tests: a resolution of less than 560 KeV FWHM has been obtained for neutrons of 2.45 MeV, in a typical running configuration.

  11. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-10-25

    At high energies, the relevant degrees of freedom are Wilson lines--infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to the projectile and target, includes both up and down fan diagrams and pomeron loops.

  12. Excitation of the 3p states in electron-sodium scattering at intermediate energies

    SciTech Connect

    Kamali, M. Z. M.; Wong, B. R.; Chin, J. H.; Ratnavelu, K.

    2014-03-05

    A coupled-channel-optical method (CCOM), to investigate the excitation of the 3p states for e{sup −}-Na scattering at intermediate energies, is reported. Nine atomic states( Na(3s), Na(3p), Na(4s), Na(3d), Na(4p), Na(5s), Na(4d), Na(5p), Na(5d) ) together with three optical potentials are used in this work. The inelastic differential cross sections (DCS) as well as the reduced Stokes parameters are compared with latest theoretical data and experimental measurements.

  13. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2007-01-01

    At high energies, the relevant degrees of freedom are Wilson lines--infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

  14. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-06-16

    At high energies, the relevant degrees of freedom are Wilson lines - infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

  15. A scatter correction method for contrast-enhanced dual-energy digital breast tomosynthesis.

    PubMed

    Lu, Yihuan; Peng, Boyu; Lau, Beverly A; Hu, Yue-Houng; Scaduto, David A; Zhao, Wei; Gindi, Gene

    2015-08-21

    Contrast-enhanced dual energy digital breast tomosynthesis (CE-DE-DBT) is designed to image iodinated masses while suppressing breast anatomical background. Scatter is a problem, especially for high energy acquisition, in that it causes severe cupping artifact and iodine quantitation errors. We propose a patient specific scatter correction (SC) algorithm for CE-DE-DBT. The empirical algorithm works by interpolating scatter data outside the breast shadow into an estimate within the breast shadow. The interpolated estimate is further improved by operations that use an easily obtainable (from phantoms) table of scatter-to-primary-ratios (SPR)--a single SPR value for each breast thickness and acquisition angle. We validated our SC algorithm for two breast emulating phantoms by comparing SPR from our SC algorithm to that measured using a beam-passing pinhole array plate. The error in our SC computed SPR, averaged over acquisition angle and image location, was about 5%, with slightly worse errors for thicker phantoms. The SC projection data, reconstructed using OS-SART, showed a large degree of decupping. We also observed that SC removed the dependence of iodine quantitation on phantom thickness. We applied the SC algorithm to a CE-DE-mammographic patient image with a biopsy confirmed tumor at the breast periphery. In the image without SC, the contrast enhanced tumor was masked by the cupping artifact. With our SC, the tumor was easily visible. An interpolation-based SC was proposed by (Siewerdsen et al 2006 Med. Phys. 33 187-97) for cone-beam CT (CBCT), but our algorithm and application differ in several respects. Other relevant SC techniques include Monte-Carlo and convolution-based methods for CBCT, storage of a precomputed library of scatter maps for DBT, and patient acquisition with a beam-passing pinhole array for breast CT. Our SC algorithm can be accomplished in clinically acceptable times, requires no additional imaging hardware or extra patient dose and is

  16. A Search for electron neutrino appearance at the Delta m**2 ~ 1- eV**2 scale

    SciTech Connect

    Aguilar-Arevalo, A.A.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; Djurcic, Z.; /Columbia U. /Fermilab

    2007-04-01

    The MiniBooNE Collaboration reports first results of a search for {upsilon}{sub e} appearance in a {upsilon}{sub {mu}} beam. With two largely independent analyses, we observe no significant excess of events above background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two neutrino appearance-only oscillation model.

  17. Limits on low energy photon-photon scattering from an experiment on magnetic vacuum birefringence

    SciTech Connect

    Bregant, M.; Cantatore, G.; Della Valle, F.; Lozza, V.; Milotti, E.; Raiteri, G.; Zavattini, E.; Carusotto, S.; Polacco, E.; Cimino, R.; Di Domenico, G.; Zavattini, G.; Gastaldi, U.; Ruoso, G.; Karuza, M.

    2008-08-01

    Experimental bounds on induced vacuum magnetic birefringence can be used to improve present photon-photon scattering limits in the electronvolt energy range. Measurements with the Polarizzazione del Vuoto con Laser apparatus [E. Zavattini et al., Phys. Rev. D 77, 032006 (2008)] at both {lambda}=1064 and 532 nm lead to bounds on the parameter A{sub e}, describing nonlinear effects in QED, of A{sub e}{sup (1064)}<6.6x10{sup -21} T{sup -2}-1064 nm and A{sub e}{sup (532)}<6.3x10{sup -21} T{sup -2}-532 nm, respectively, at 95% confidence level, compared to the predicted value of A{sub e}=1.32x10{sup -24} T{sup -2}. The total photon-photon scattering cross section may also be expressed in terms of A{sub e}, setting bounds for unpolarized light of {sigma}{sub {gamma}}{sub {gamma}}{sup (1064)}<4.6x10{sup -62} m{sup 2} and {sigma}{sub {gamma}}{sub {gamma}}{sup (532)}<2.7x10{sup -60} m{sup 2}. Compared to the expected QED scattering cross section these results are a factor of {approx_equal}2x10{sup 7} higher and represent an improvement of a factor about 500 on previous bounds based on ellipticity measurements and of a factor of about 10{sup 10} on bounds based on direct stimulated scattering measurements.

  18. Stimulated scattering in laser driven fusion and high energy density physics experiments

    SciTech Connect

    Yin, L. Albright, B. J.; Rose, H. A.; Montgomery, D. S.; Kline, J. L.; Finnegan, S. M.; Bergen, B.; Bowers, K. J.; Kirkwood, R. K.; Milovich, J.

    2014-09-15

    In laser driven fusion and high energy density physics experiments, one often encounters a kλ{sub D} range of 0.15 < kλ{sub D} < 0.5, where stimulated Raman scattering (SRS) is active (k is the initial electron plasma wave number and λ{sub D} is the Debye length). Using particle-in-cell simulations, the SRS reflectivity is found to scale as ∼ (kλ{sub D}){sup −4} for kλ{sub D} ≳ 0.3 where electron trapping effects dominate SRS saturation; the reflectivity scaling deviates from the above for kλ{sub D} < 0.3 when Langmuir decay instability (LDI) is present. The SRS risk is shown to be highest for kλ{sub D} between 0.2 and 0.3. SRS re-scattering processes are found to be unimportant under conditions relevant to ignition experiments at the National Ignition Facility (NIF). Large-scale simulations of the hohlraum plasma show that the SRS wavelength spectrum peaks below 600 nm, consistent with most measured NIF spectra, and that nonlinear trapping in the presence of plasma gradients determines the SRS spectral peak. Collisional effects on SRS, stimulated Brillouin scattering (SBS), LDI, and re-scatter, together with three dimensional effects, are examined. Effects of collisions are found to include de-trapping as well as cross-speckle electron temperature variation from collisional heating, the latter of which reduces gain, introduces a positive frequency shift that counters the trapping-induced negative frequency shift, and affects SRS and SBS saturation. Bowing and breakup of ion-acoustic wavefronts saturate SBS and cause a dramatic, sharp decrease in SBS reflectivity. Mitigation of SRS and SBS in the strongly nonlinear trapping regime is discussed.

  19. Search for Electron Neutrino Appearance at the {delta}m{sup 2}{approx}1 eV{sup 2} Scale

    SciTech Connect

    Aguilar-Arevalo, A. A.; Bugel, L.; Coney, L.; Conrad, J. M.; Djurcic, Z.; Mahn, K. B. M.; Monroe, J.; Schmitz, D.; Shaevitz, M. H.; Sorel, M.; Zeller, G. P.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.; Patterson, R. B.; Shoemaker, F. C.; Tanaka, H. A.; Brice, S. J.; Brown, B. C.; Finley, D. A.

    2007-06-08

    The MiniBooNE Collaboration reports first results of a search for {nu}{sub e} appearance in a {nu}{sub {mu}} beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model.

  20. Energy dependence of the optical model of neutron scattering from niobium

    SciTech Connect

    Smith, A.B.; Guenther, P.T.; Lawson, R.D.

    1985-05-01

    Neutron differential-elastic-scattering cross sections of niobium were measured from 1.5 to 10.0 MeV at intervals of less than or equal to200 keV below 4.0 MeV, and of approx. =500 keV from 4.0 to 10.0 MeV. Ten to more than fifty differential-cross-section values were determined at each incident energy, distributed over the angular range approx. =20 to 160/sup 0/. The observed values were interpreted in the context of the spherical optical-statistical model. It was found that the volume integral of the real potential decreased with energy whereas the integral of the imaginary part increased. The energy dependence in both cases was consistent with a linear variation. There is a dispersion relationship between the real and imaginary potentials, and when this was used, in conjunction with the experimental imaginary potential, it was possible to predict the observed energy dependence of the real potential to a good degree of accuracy, thus supporting the consistency of the data and its analysis. The real-potential well depths needed to give the correct binding energies of the 2d/sub 5/2/, 3s/sub 1/2/, 2d/sub 3/2/ and 1g/sub 7/2/ particle states and of the 1g/sub 9/2/ hole state are in reasonable agreement with those given by a linear extrapolation of the scattering potential. However, the well depths needed to give the observed binding of the 2p/sub 3/2/, 1f/sub 5/2/ and 2p/sub 1/2/ hole states are about 10% less than the extrapolated values. 40 refs., 5 figs.

  1. Charge states of medium energy He ions scattered from single and poly-crystal surfaces

    NASA Astrophysics Data System (ADS)

    Okazawa, T.; Shibuya, K.; Nishimura, T.; Kido, Y.

    2007-03-01

    High-resolution medium energy ion scattering (MEIS) spectroscopy has unveiled fine structures of surfaces and interfaces. However, problematic issues arise due to its excellent energy resolution. In particular, when one uses He+ beams, the He+ fraction η+ (1) for the scattering component from top-layer atoms is frequently non-equilibrated owing to short exit path length. This leads to significant uncertainties of the absolute amount of atoms located on top of a surface. To overcome this difficulty, it is essential to acquire reliable data of equilibrium and non-equilibrium charge fractions and also to model the charge exchange process based on a simple picture. In this paper, we analyze the MEIS spectra from single and poly crystals of Si, Ni and Cu together with c-axis oriented graphite and derive electron capture (σ10) and loss (σ01) cross sections dependent on emerging ion velocity. Here, we assume that a He ion when arrives at a Maffin-tin sphere after a large angle collision takes the He+ state and then undergoes many charge exchanging collisions with valence electrons until leaving an electronic surface. The velocity dependent σ10 and σ01 values derived well reproduce equilibrium and non-equilibrium charge fractions of He+ except for graphite and poly-crystal Si at relatively large emerging angles. Such a deviation comes from the markedly anisotropic distributions of the valence electrons of Si and graphite with strong covalent bonds.

  2. Review of the Lujan neutron scattering center: basic energy sciences prereport February 2009

    SciTech Connect

    Hurd, Alan J; Rhyne, James J; Lewis, Paul S

    2009-01-01

    The Lujan Neutron Scattering Center (Lujan Center) at LANSCE is a designated National User Facility for neutron scattering and nuclear physics studies with pulsed beams of moderated neutrons (cold, thermal, and epithermal). As one of five experimental areas at the Los Alamos Neutron Science Center (LANSCE), the Lujan Center hosts engineers, scientists, and students from around the world. The Lujan Center consists of Experimental Room (ER) 1 (ERl) built by the Laboratory in 1977, ER2 built by the Office of Basic Energy Sciences (BES) in 1989, and the Office Building (622) also built by BES in 1989, along with a chem-bio lab, a shop, and other out-buildings. According to a 1996 Memorandum of Agreement (MOA) between the Defense Programs (DP) Office of the National Nuclear Security Agency (NNSA) and the Office of Science (SC, then the Office of Energy Research), the Lujan Center flight paths were transferred from DP to SC, including those in ERI. That MOA was updated in 2001. Under the MOA, NNSA-DP delivers neutron beam to the windows of the target crypt, outside of which BES becomes the 'landlord.' The leveraging nature of the Lujan Center on the LANSCE accelerator is a substantial annual leverage to the $11 M BES operating fund worth approximately $56 M operating cost of the linear accelerator (LINAC)-in beam delivery.

  3. Information stored in high-Q space: Role of high energy scattering

    SciTech Connect

    Egami, T.; Dmowski, W. Billinge, S.J.L. Kycia, S. Eberhardt, A.S.

    1997-07-01

    Much of crystallographic diffraction measurements are focused on obtaining information with Q(=4{pi}sin{theta}/{lambda}) below 17{Angstrom}{sup {minus}1} or d{gt}0.35{Angstrom}, with the implicit assumption that no useful information is stored in the Q space above. However, this assumption is valid only with respect to the periodic lattice structure. Actually, high-Q space is full of information on the local atomic structure that could be of major importance in some cases. We discuss high energy x-ray or neutron scattering as the methods of obtaining the data from the high-Q space, and the atomic pair-distribution function (PDF) analysis as the means of extracting information from such data. Preliminary data of our recent high-energy x-ray scattering measurement on a MX compound are shown for which this type of analysis is likely to play a significant role in understanding the properties. {copyright} {ital 1997 American Institute of Physics.}

  4. Spin wave excitations in low-energy electron scattering off Fe surfaces

    NASA Astrophysics Data System (ADS)

    Vernoy, Michael; Hopster, Herbert

    2002-03-01

    For the last two decades, SPEELS has been instrumental in the investigation of Stoner excitations in ferromagnets. By analyzing the spin of both the scattered electron beam and the incident beam, so called “complete” experiments were performed [1,2]. By eliminating the spin analysis of the scattered beam it has become possible to examine short wavelength spin wave excitations [3]. We constructed a 127 degree cylindrical deflector spectrometer with an analyzer rotatable to 70 degrees. The polarized electron beam is produced by a negative electron affinity GaAs photocathode. Initial data were taken with a primary beam energy of 20 V at a resolution of 50 meV FWHM on thick Fe/GaAs films. Spin asymmetries show the Stoner continuum as noted in the previous complete experiments as well as an additional feature in the 100-300 meV energy loss region. Angle dependent data will be presented. [1] J. Kirschner, Phys. Rev. Lett. 55, 973 (1985). [2] D. L. Abraham and H. Hopster, Phys. Rev. Lett. 59, 2333 (1987). [3] M. Plihal, D. L. Mills, and J. Kirschner, Phys. Rev. Lett. 82, 2579 (1999).

  5. Simulation experiments for gamma-ray mapping of planetary surfaces: Scattering of high-energy neutrons

    NASA Technical Reports Server (NTRS)

    Brueckner, J.; Englert, P.; Reedy, R. C.; Waenke, H.

    1986-01-01

    The concentration and distribution of certain elements in surface layers of planetary objects specify constraints on models of their origin and evolution. This information can be obtained by means of remote sensing gamma-ray spectroscopy, as planned for a number of future space missions, i.e., Mars, Moon, asteroids, and comets. To investigate the gamma-rays made by interactions of neutrons with matter, thin targets of different composition were placed between a neutron-source and a high-resolution germanium spectrometer. Gamma-rays in the range of 0.1 to 8 MeV were accumulated. In one set of experiments a 14-MeV neutron generator using the T(d,n) reaction as neutron-source was placed in a small room. Scattering in surrounding walls produced a spectrum of neutron energies from 14 MeV down to thermal. This complex neutron-source induced mainly neutron-capture lines and only a few scattering lines. As a result of the set-up, there was a considerable background of discrete lines from surrounding materials. A similar situation exists under planetary exploration conditions: gamma-rays are induced in the planetary surface as well as in the spacecraft. To investigate the contribution of neutrons with higher energies, an experiment for the measurement of prompt gamma radiation was set up at the end of a beam-line of an isochronous cyclotron.

  6. An experimental study of energy dependence of saturation thickness of multiply scattered gamma rays in binary alloys

    SciTech Connect

    Singh, Gurvinderjit; Singh, Bhajan Sandhu, B. S.

    2015-08-28

    The present measurements are carried out to investigate the multiple scattering of 662 keV gamma photons emerging from targets of binary alloys (brass and soldering material). The scattered photons are detected by 51 mm × 51 mm NaI(Tl) scintillation detector whose response unscrambling converting the observed pulse–height distribution to a true photon energy spectrum, is obtained with the help of 10 × 10 inverse response matrix. The numbers of multiply scattered events, having same energy as in the singly scattered distribution, first increases with target thickness and then saturate. The application of response function of scintillation detector does not result in any change of measured saturation thickness. Monte Carlo calculation supports the present experimental results.

  7. A comparison of phantom scatter from flattened and flattening filter free high-energy photon beams

    SciTech Connect

    Richmond, Neil; Allen, Vince; Daniel, Jim; Dacey, Rob; Walker, Chris

    2015-04-01

    Flattening filter free (FFF) photon beams have different dosimetric properties from those of flattened beams. The aim of this work was to characterize the collimator scatter (S{sub c}) and total scatter (S{sub cp}) from 3 FFF beams of differing quality indices and use the resulting mathematical fits to generate phantom scatter (S{sub p}) data. The similarities and differences between S{sub p} of flattened and FFF beams are described. S{sub c} and S{sub cp} data were measured for 3 flattened and 3 FFF high-energy photon beams (Varian 6 and 10 MV and Elekta 6 MV). These data were fitted to logarithmic power law functions with 4 numerical coefficients. The agreement between our experimentally determined flattened beam S{sub p} and published data was within ± 1.2% for all 3 beams investigated and all field sizes from 4 × 4 to 40 × 40 cm{sup 2}. For the FFF beams, S{sub p} was only within 1% of the same flattened beam published data for field sizes between 6 × 6 and 14 × 14 cm{sup 2}. Outside this range, the differences were much greater, reaching − 3.2%, − 4.5%, and − 4.3% for the fields of 40 × 40 cm{sup 2} for the Varian 6-MV, Varian 10-MV, and Elekta 6-MV FFF beams, respectively. The FFF beam S{sub p} increased more slowly with increasing field size than that of the published and measured flattened beam of a similar reference field size quality index, i.e., there is less Phantom Scatter than that found with flattened beams for a given field size. This difference can be explained when the fluence profiles of the flattened and FFF beams are considered. The FFF beam has greatly reduced fluence off axis, especially as field size increases, compared with the flattened beam profile; hence, less scatter is generated in the phantom reaching the central axis.

  8. Spin effects in high-energy photon-hadron scattering in QCD

    SciTech Connect

    Goloskokov, S.V.; Listopadov, O.A.

    1995-09-01

    Spin effects at high energies and momentum transfers {vert_bar}t{vert_bar} > 1 GeV{sup 2} are analyzed for elastic quark-photon scattering. The ratio of the spin-flip and non-spin-flip amplitudes in the same order of perturbative QCD is found to be independent of energy. It is shown that the contribution of the spin-dependent quark-pomeron vertex to the photon spin-flip amplitude is enhanced by off-mass-shell effects in the quark loop. As a result, this amplitude can become as large as 20-30% of the non-spin-flip amplitude. The cross section is found to depend on the form factor and on contributions of order {alpha}{sub s}{sup 3} the non-spin-flip amplitude. 12 refs., 4 figs.

  9. Virtual Compton Scattering at low energy and the generalized polarizabilities of the nucleon

    SciTech Connect

    Helene Fonvieille

    2003-05-01

    Virtual Compton Scattering (VCS) {gamma}*p {yields} {gamma}p at low CM energy gives access to the Generalized Polarizabilities of the nucleon. These observables generalize the concept of electromagnetic polarizabilities to the case of a virtual photon. Dedicated VCS experiments have been performed at MAMI, Jefferson Lab and MIT-Bates. The experimental status is reviewed, including analysis methods and physics results. The measurement of absolute (ep {yields} ep{gamma}) cross sections allows the extraction of the two unpolarized VCS structure functions P{sub LL}-P{sub TT}/{epsilon} and P{sub LT}, which are combinations of the Generalized Polarizabilities of the proton. Future prospects in the field of VCS at low energy are also presented.

  10. Observations on open and closed string scattering amplitudes at high energies

    NASA Astrophysics Data System (ADS)

    Caputa, Pawel; Hirano, Shinji

    2012-02-01

    We study massless open and closed string scattering amplitudes in flat space at high energies. Similarly to the case of AdS space, we demonstrate that, under the T-duality map, the open string amplitudes are given by the exponential of minus minimal surface areas whose boundaries are cusped closed loops formed by lightlike momentum vectors. We show further that the closed string amplitudes are obtained by gluing two copies of minimal surfaces along their cusped lightlike boundaries. This can be thought of as a manifestation of the Kawai-Lewellen-Tye (KLT) relation at high energies. We also discuss the KLT relation in AdS/CFT and its possible connection to amplitudes in mathcal{N} = {8} supergravity as well as the correlator/amplitude duality.

  11. Partial-wave analysis for elastic p{sup 13}C scattering at astrophysical energies

    SciTech Connect

    Dubovichenko, S. B.

    2012-03-15

    A standard partial-wave analysis was performed on the basis of known measurements of differential cross sections for elastic p{sup 13}C scattering at energies in the range 250-750 keV. This analysis revealed that, in the energy range being considered, it is sufficient to take into account the {sup 3}S{sub 1} wave alone. A potential for the triplet {sup 3}S{sub 1}-wave state of the p{sup 13}C system in the region of the J{sup p}T = 1{sup -1} resonance at 0.55 MeV was constructed on the basis of the phase shifts obtained from the aforementioned partial-wave analysis.

  12. Cross sections for elastic electron scattering by tetramethylsilane in the intermediate-energy range

    SciTech Connect

    Sugohara, R. T.; Lee, M.-T.; Iga, I.; Souza, G. L. C. de; Homem, M. G. P.

    2011-12-15

    Organosilicon compounds are of current interest due to the numerous applications of these species in industries. Some of these applications require the knowledge of electron collision cross sections, which are scarce for such compounds. In this work, we report absolute values of differential, integral, and momentum-transfer cross sections for elastic electron scattering by tetramethylsilane (TMS) measured in the 100-1000 eV energy range. The relative-flow technique is used to normalize our data. In addition, the independent-atom-model (IAM) and the additivity rule (AR), widely used to model electron collisions with light hydrocarbons, are also applied for e{sup -}-TMS interaction. The comparison of our measured results of cross sections and the calculated data shows good agreement, particularly near the higher-end of incident energies.

  13. Neutrino-induced reactions and neutrino scattering with nuclei in low and high neutrino energy

    NASA Astrophysics Data System (ADS)

    Cheoun, Myung-Ki; Ha, Eunja; Yang, Ghil-Seok; Kim, K. S.; Kajino, T.

    2016-06-01

    We reviewed present status regarding theoretical approaches for neutrino-induced reactions and neutrino scattering. With a short introduction of relevant data, our recent calculations by distorted-wave Born approximation (DWBA) for quasielastic region are presented for MiniBooNE data. We also discussed that one step-process estimated by the DWBA is comparable to the two-step process, which has been usually used in the neutrino-nucleosynthesis. For much higher energy neutrino data, such as NOMAD data, elementary process approach was shown to be useful instead of using complicated nuclear models. But, in the low energy region, detailed nuclear structure model, such as QRPA and shell model, turn out to be inescapable to explain the reaction data.

  14. Carrier scattering processes and low energy phonon spectroscopy in hybrid perovskites crystals

    NASA Astrophysics Data System (ADS)

    Even, Jacky; Paofai, Serge; Bourges, Philippe; Letoublon, Antoine; Cordier, Stéphane; Durand, Olivier; Katan, Claudine

    2016-03-01

    Despite the wealth of research conducted the last three years on hybrid organic perovskites (HOP), several questions remain open including: to what extend the organic moiety changes the properties of the material as compared to allinorganic (AIP) related perovskite structures. To ultimately reach an answer to this question, we have recently introduced two approaches that were designed to take the stochastic molecular degrees of freedom into account, and suggested that the high temperature cubic phase of HOP and AIP is an appropriate reference phase to rationalize HOP's properties. In this paper, we recall the main concepts and discuss more specifically the various possible couplings between charge carriers and low energy excitations such as acoustic and optical phonons. As available experimental or simulated data on low energy excitations are limited, we also present preliminary neutron scattering and ultrasonic measurements obtained and freshly prepared single crystals of CH3NH3PbBr3.

  15. A model for soft high-energy scattering: Tensor pomeron and vector odderon

    SciTech Connect

    Ewerz, Carlo; Maniatis, Markos

    2014-03-15

    A model for soft high-energy scattering is developed. The model is formulated in terms of effective propagators and vertices for the exchange objects: the pomeron, the odderon, and the reggeons. The vertices are required to respect standard rules of QFT. The propagators are constructed taking into account the crossing properties of amplitudes in QFT and the power-law ansätze from the Regge model. We propose to describe the pomeron as an effective spin 2 exchange. This tensor pomeron gives, at high energies, the same results for the pp and pp{sup -bar} elastic amplitudes as the standard Donnachie–Landshoff pomeron. But with our tensor pomeron it is much more natural to write down effective vertices of all kinds which respect the rules of QFT. This is particularly clear for the coupling of the pomeron to particles carrying spin, for instance vector mesons. We describe the odderon as an effective vector exchange. We emphasise that with a tensor pomeron and a vector odderon the corresponding charge-conjugation relations are automatically fulfilled. We compare the model to some experimental data, in particular to data for the total cross sections, in order to determine the model parameters. The model should provide a starting point for a general framework for describing soft high-energy reactions. It should give to experimentalists an easily manageable tool for calculating amplitudes for such reactions and for obtaining predictions which can be compared in detail with data. -- Highlights: •A general model for soft high-energy hadron scattering is developed. •The pomeron is described as effective tensor exchange. •Explicit expressions for effective reggeon–particle vertices are given. •Reggeon–particle and particle–particle vertices are related. •All vertices respect the standard C parity and crossing rules of QFT.

  16. Theory of evaporative cooling with energy-dependent elastic scattering cross section and application to metastable helium

    SciTech Connect

    Tol, Paul J.J.; Hogervorst, Wim; Vassen, Wim

    2004-07-01

    The kinetic theory of evaporative cooling developed by Luiten et al. [Phys. Rev. A 53, 381 (1996)] is extended to include the dependence of the elastic scattering cross section on collision energy. We introduce a simple approximation by which the transition range between the low-temperature limit and the unitarity limit is described as well. Applying the modified theory to our measurements on evaporative cooling of metastable helium, we find a scattering length a=10(5) nm.

  17. Breakup and Elastic Scattering in the {sup 9}Be + {sup 144}Sm system at near barrier energies

    SciTech Connect

    Paes, B.; Garcia, V. N.; Lubian, J.; Gomes, P. R. S.; Padron, I.

    2010-05-21

    Breakup and elastic scattering in the Be + {sup 144}Sm system, at near barrier energies, are investigated. We calculate theoretically the non-capture breakup cross section by performing coupled reaction channel calculations. The energy dependence of the optical potential does not show the usual threshold anomaly found in tightly bound systems.

  18. Relativistic off-mass-shell and off-energy-shell scattering theories: an application of the rotation and Lorentz groups

    SciTech Connect

    Giebink, D.R.

    1980-10-01

    A relativistic, phenomenological scattering theory for particles with arbitrary spin is presented, and the relation between off-mass-shell and off-energy-shell theories is discussed. The theory is formulated from the Hilbert-space representation of particles with spin in relativistic quantum mechanics. This topic is reviewed in a basis-independent manner by appealing to the properties of the rotation and Lorentz groups and their representations. Spin is discussed and a set of basis state vectors for the single-particle Hilbert space is derived from this perspective. Two- and three-particle Hilbert-space bases are then constructed, and angular momentum is discussed. The z-circumflex and helicity bases are presented as examples of the general procedure. These foundations allow the on-shell scattering amplitude to be defined. The space-inversion and time-reversal properties of this amplitude suggest that a new scattering function be defined such that a continuation of that function to negative energies can be considered. Antiparticle scattering events are associated with the continued function, and the CPT theorem arises as a natural consequence of this association. Moreover, these considerations lead to the definition of an off-mass-shell scattering function. The resulting off-mass-shell scattering theory has a number of very appealing properties. The off-energy-shell theory is dependent on fewer variables than the off-mass-shell theory, and is more susceptible to a phenomenological treatment.

  19. High energy scattering and renormalization in the NS+ string and large N QCD

    NASA Astrophysics Data System (ADS)

    Rojas Fernandez, Francisco Javier

    In this work we study a model of open strings and its low energy limit as a device to understand certain aspects of gauge theory. More specifically, we use the even G-parity sector of the Neveu-Schwarz model with the open strings endpoints attached to a stack of N coincident Dp-branes as our starting point. After various projections, the low energy limit of this string theory is pure Yang-Mills and the field theory limit of the sum of the planar open string diagrams becomes to the sum of the leading diagrams of 't Hooft's large N expansion of QCD. The typical expression for the amplitude we study here, namely for the scattering of open string massless vector bosons, comes in an integral form that shows multiple (spurious) divergences in various corners of the integration region. However, we regularize all of these divergences by momentarily suspending total momentum conservation by an amount p, as first suggested by Goddard and by Neveu and Scherk [1, 2], and construct the appropriate counterterms. We show that all the counterterms we need to introduce, after analytic continuation to p = 0, are all proportional to the tree amplitude which then amounts to a renormalization the string coupling constant. Using this renormalized expression, we also study its high-energy behavior. We obtain the one-loop ( O (g2)) correction to the open string Regge trajectory alpha(t) also as a function of the spacetime dimensionality of the Dp-branes. We also study the field theory limit of the new trajectory which amounts to analyzing the small t behavior of alpha(t). We obtain the exact same answer given by conventional calculations in dimensionally regularized gauge theory which puts the gluon on a Regge trajectory of order g2. We think that this is a useful insight that open string theory provides into the understanding of gauge theory. Additionally we study the behavior of the new trajectory alpha(t) for t away from zero which is relevant for open string physics. Finally we work

  20. Internal strain gradients quantified in bone under load using high-energy X-ray scattering.

    SciTech Connect

    Stock, S.R.; Yuan, F.; Brinson, L.C.; Almer, J.D.

    2011-01-01

    High-energy synchrotron X-ray scattering (>60 keV) allows noninvasive quantification of internal strains within bone. In this proof-of-principle study, wide angle X-ray scattering maps internal strain vs position in cortical bone (murine tibia, bovine femur) under compression, specifically using the response of the mineral phase of carbonated hydroxyapatite. The technique relies on the response of the carbonated hydroxyapatite unit cells and their Debye cones (from nanocrystals correctly oriented for diffraction) to applied stress. Unstressed, the Debye cones produce circular rings on the two-dimensional X-ray detector while applied stress deforms the rings to ellipses centered on the transmitted beam. Ring ellipticity is then converted to strain via standard methods. Strain is measured repeatedly, at each specimen location for each applied stress. Experimental strains from wide angle X-ray scattering and an attached strain gage show bending of the rat tibia and agree qualitatively with results of a simplified finite element model. At their greatest, the apatite-derived strains approach 2500 {micro}{var_epsilon} on one side of the tibia and are near zero on the other. Strains maps around a hole in the femoral bone block demonstrate the effect of the stress concentrator as loading increased and agree qualitatively with the finite element model. Experimentally, residual strains of approximately 2000 {micro}{var_epsilon} are present initially, and strain rises to approximately 4500 {micro}{var_epsilon} at 95 MPa applied stress (about 1000 {micro}{var_epsilon} above the strain in the surrounding material). The experimental data suggest uneven loading which is reproduced qualitatively with finite element modeling.

  1. Full dimension Rb2He ground triplet potential energy surface and quantum scattering calculations.

    PubMed

    Guillon, Grégoire; Viel, Alexandra; Launay, Jean-Michel

    2012-05-01

    We have developed a three-dimensional potential energy surface for the lowest triplet state of the Rb(2)He complex. A global analytic fit is provided as in the supplementary material [see supplementary material at http://dx.doi.org/10.1063/1.4709433 for the corresponding Fortran code]. This surface is used to perform quantum scattering calculations of (4)He and (3)He colliding with (87)Rb(2) in the partial wave J = 0 at low and ultralow energies. For the heavier helium isotope, the computed vibrational relaxation probabilities show a broad and strong shape resonance for a collisional energy of 0.15 K and a narrow Feshbach resonance at about 17 K for all initial Rb(2) vibrational states studied. The broad resonance corresponds to an efficient relaxation mechanism that does not occur when (3)He is the colliding partner. The Feshbach resonance observed at higher collisional energy is robust with respect to the isotopic substitution. However, its effect on the vibrational relaxation mechanism is faint for both isotopes. PMID:22583230

  2. Full dimension Rb2He ground triplet potential energy surface and quantum scattering calculations

    NASA Astrophysics Data System (ADS)

    Guillon, Grégoire; Viel, Alexandra; Launay, Jean-Michel

    2012-05-01

    We have developed a three-dimensional potential energy surface for the lowest triplet state of the Rb2He complex. A global analytic fit is provided as in the supplementary material [see supplementary material at http://dx.doi.org/10.1063/1.4709433E-JCPSA6-136-034218 for the corresponding Fortran code]. This surface is used to perform quantum scattering calculations of 4He and 3He colliding with 87Rb2 in the partial wave J = 0 at low and ultralow energies. For the heavier helium isotope, the computed vibrational relaxation probabilities show a broad and strong shape resonance for a collisional energy of 0.15 K and a narrow Feshbach resonance at about 17 K for all initial Rb2 vibrational states studied. The broad resonance corresponds to an efficient relaxation mechanism that does not occur when 3He is the colliding partner. The Feshbach resonance observed at higher collisional energy is robust with respect to the isotopic substitution. However, its effect on the vibrational relaxation mechanism is faint for both isotopes.

  3. Low-energy neutral-current neutrino scattering on {sup 128,130}Te isotopes

    SciTech Connect

    Tsakstara, V.; Kosmas, T. S.

    2011-05-15

    Differential, total, and cumulative cross section calculations for neutral current neutrino scattering on {sup 128,130}Te isotopes are performed in the context of the quasiparticle random phase approximation by utilizing realistic two-nucleon forces. These isotopes are the main contents of detectors of ongoing experiments with multiple neutrino physics goals (COBRA and CUORE at Gran Sasso), including potential low-energy astrophysical neutrino (solar, supernova, geoneutrinos) detection. The incoming neutrino energy range adopted in our calculations ({epsilon}{sub {nu}{<=}1}00 MeV) covers the low-energy {beta}-beam neutrinos and the pion-muon stopped neutrino beams existing or planned to be conducted at future neutron spallation sources. The aim of these facilities is to measure neutrino-nucleus cross sections at low and intermediate neutrino energies with the hope of shedding light on open problems in neutrino-induced reactions on nuclei and neutrino astrophysics. Such probes motivate theoretical studies on weak responses of various nuclear systems; thus the evaluated cross sections may be useful in this direction.

  4. Low energy elastic electron scattering from CF{sub 3}Br molecules

    SciTech Connect

    Hargreaves, L. R.; Brunton, J. R.; Maddern, T. M.; Brunger, M. J.

    2015-03-28

    CF{sub 3}Br is a potentially valuable precursor molecule for generating beams of gas phase Br radicals suitable for electron collisions studies. However, the utility of CF{sub 3}Br for this purpose depends critically on the availability of sound scattering cross sections to allow the contribution of the precursor to be isolated within the total scattering signal. To this end, here we present elastic differential cross section (DCS) measurements for CF{sub 3}Br at incident energies between 15 and 50 eV. Comparison of these DCSs to those from the only other available experimental study [Sunohara et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1843 (2003)] and a Schwinger multichannel with pseudo potentials (SMCPPs) calculation [Bettega et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1263 (2003)] shows generally a very good accord. Integral elastic and momentum transfer cross sections, derived from our DCSs, are also found to be in quite good agreement with the SMCPP results.

  5. Four-jet production in single- and double-parton scattering within high-energy factorization

    NASA Astrophysics Data System (ADS)

    Kutak, Krzysztof; Maciula, Rafal; Serino, Mirko; Szczurek, Antoni; van Hameren, Andreas

    2016-04-01

    We perform a first study of 4-jet production in a complete high-energy factorization (HEF) framework. We include and discuss contributions from both single-parton scattering (SPS) and double-parton scattering (DPS). The calculations are performed for kinematical situations relevant for two experimental measurements (ATLAS and CMS) at the LHC. We compare our results to those reported by the ATLAS and CMS collaborations for different sets of kinematical cuts. The results of the HEF approach are compared with their counterparts for collinear factorization. For symmetric cuts the DPS HEF result is considerably smaller than the one obtained with collinear factorization. The mechanism leading to this difference is of kinematical nature. We conclude that an analysis of inclusive 4-jet production with asymmetric p T -cuts below 50 GeV would be useful to enhance the DPS contribution relative to the SPS contribution. In contrast to the collinear approach, the HEF approach nicely describes the distribution of the Δ S variable, which involves all four jets and their angular correlations.

  6. Data acquisition and analysis for the energy-subtraction Compton scatter camera for medical imaging

    NASA Astrophysics Data System (ADS)

    Khamzin, Murat Kamilevich

    In response to the shortcomings of the Anger camera currently being used in conventional SPECT, particularly the trade-off between sensitivity and spatial resolution, a novel energy-subtraction Compton scatter camera, or the ESCSC, has been proposed. A successful clinical implementation of the ESCSC could revolutionize the field of SPECT. Features of this camera include utilization of silicon and CdZnTe detectors in primary and secondary detector systems, list-mode time stamping data acquisition, modular architecture, and post-acquisition data analysis. Previous ESCSC studies were based on Monte Carlo modeling. The objective of this work is to test the theoretical framework developed in previous studies by developing the data acquisition and analysis techniques necessary to implement the ESCSC. The camera model working in list-mode with time stamping was successfully built and tested thus confirming potential of the ESCSC that was predicted in previous simulation studies. The obtained data were processed during the post-acquisition data analysis based on preferred event selection criteria. Along with the construction of a camera model and proving the approach, the post-acquisition data analysis was further extended to include preferred event weighting based on the likelihood of a preferred event to be a true preferred event. While formulated to show ESCSC capabilities, the results of this study are important for any Compton scatter camera implementation as well as for coincidence data acquisition systems in general.

  7. Quantifying scattered sound energy from a single tree by means of reverberation time.

    PubMed

    Yang, Hong-Seok; Kang, Jian; Cheal, Chris; Van Renterghem, Timothy; Botteldooren, Dick

    2013-07-01

    Trees in urban spaces surrounded by buildings may be effective in dispersing sound energy, and this could affect sound level distribution and street canyon reverberation. To quantify this effect of trees with a view to including it in numerical predictions, this paper examines sound scattering from a single tree in open field by means of reverberation time (RT). Five trees of different species and crown sizes were considered. The influence of ground condition, receiver height, crown size and shape, foliage condition, and source-receiver angle and distance has been assessed. The results show that RT20 is proportional to the tree crown size, which is the most important factor. The maximum RT20 measured was 0.28 s at 4000 Hz for the studied trees when in leaf (with foliage). The presence of leaves increased RT20 at high frequencies, typically by 0.08 s at 4000 Hz. It was also demonstrated that the source-receiver angle can affect the characteristics of decay curves significantly. With increasing source-receiver distance within 40 m, RT20 was slightly changed. It was shown that ground condition and receiver height affect the decay curves, especially at low and mid frequencies, where sound scattering is of relatively limited importance. PMID:23862804

  8. Low energy electron-molecule scattering using the R-matrix method

    NASA Astrophysics Data System (ADS)

    Gorfinkiel, Jimena

    2014-10-01

    The study of electron-molecule collisions continues to attract significant interest stimulated, in no small part, by the need for collisional data to model a number of physical environments and applied processes (e.g. the modelling of focused electron beam induced deposition and the description of the interaction of radiation with biological matter). This need for electron scattering data (cross sections but also information on the temporary negative ions, TNI, that can be formed) has motivated the renewed development of theoretical methodology and their computational implementation. I will present the latest developments in the study of low energy electron scattering from molecules and molecular clusters using the R-matrix method. Recent calculations on electron collisions with biologically relevant molecules have shed light on the formation of core-excited TNI these larger targets. The picture that emerges is much more complex than previously thought. I will discuss some examples as well as current and future developments of the methodology and software in order to provide more accurate collisional data (in particular cross sections) for bigger targets. In collaboration with Zdenek Masin, The Open University. This work was partially supported by EPSRC.

  9. Implications of optical properties of ocean, lake, and ice for ultrahigh-energy neutrino detection

    SciTech Connect

    Price, P.B.

    1997-03-01

    The collecting power and imaging ability of planned ultrahigh-energy neutrino observatories depend on wavelength-dependent absorption and scattering coefficients for the detector medium. Published data are compiled for deep ice at the South Pole, for deep fresh water at Lake Baikal, and for deep seawater. The effective scattering coefficient is smallest for the clearest deep ocean sites, whereas the absorption coefficient is an order of magnitude smaller for deep ice than for the ocean and lake sites. The effective volume per detector element as a function of energy is calculated for electromagnetic cascades produced by electron neutrinos interacting at the various sites. It is largest for deep bubble-free ice, smallest for shallow bubbly ice, and intermediate for lake and seawater. The effective volume per element is calculated for detection of positrons resulting from the capture of a few megaelectron volt supernova neutrinos by protons in the medium. This volume is proportional to the absorption length and independent of the scattering length; it is larger for ice than for seawater or lake water. {copyright} 1997 Optical Society of America

  10. SciNOvA: A Measurement of Neutrino-Nucleus Scattering in a Narrow-Band Beam

    SciTech Connect

    Paley, J.; Djurcic, Z.; Harris, D.; Tesarek, R.; Feldman, G.; Corwin, L.; Messier, M.D.; Mayer, N.; Musser, J.; Paley, J.; Tayloe, R.; /Indiana U. /Iowa State U. /Minnesota U. /South Carolina U. /Wichita State U. /William-Mary Coll.

    2010-10-15

    We propose to construct and deploy a fine-grained detector in the Fermilab NOvA 2 GeV narrow-band neutrino beam. In this beam, the detector can make unique contributions to the measurement of quasi-elastic scattering, neutral-current elastic scattering, neutral-current {pi}{sup 0} production, and enhance the NOvA measurements of electron neutrino appearance. To minimize cost and risks, the proposed detector is a copy of the SciBar detector originally built for the K2K long baseline experiment and used recently in the SciBooNE experiment.

  11. Analysis of proton scattering of stable and exotic light nuclei using an energy-dependent microscopic optical potential

    NASA Astrophysics Data System (ADS)

    Maridi, H. M.; Farag, M. Y. H.; Esmael, E. H.

    2016-01-01

    The proton elastic scattering off the 9,10,11,12Be isotopes at a wide energy range from 3 to 200 MeV/nucleon is analyzed using the optical model with the partial-wave expansion method. The microscopic optical potential (OP) is taken within the single-folding model. The density- and isospin-dependent M3YParis nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the highenergy approximation for the imaginary one. The cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation is successfully used. The volume integrals of the OP parts have systematic energy dependencies and they can be parameterized as functions of energy. From these parametrization, an energy-dependent OP can be obtained.

  12. Spin-exchange optically pumped polarized 3He target for low-energy charged particle scattering experiments

    NASA Astrophysics Data System (ADS)

    Katabuchi, T.; Buscemi, S.; Cesaratto, J. M.; Clegg, T. B.; Daniels, T. V.; Fassler, M.; Neufeld, R. B.; Kadlecek, S.

    2005-03-01

    We have constructed, tested, and calibrated a polarized He3 target system which facilitates p-He3 elastic scattering at proton energies as low as 2MeV. This system consists of a target cell placed in a uniform B field inside a scattering chamber and an external optical pumping station utilizing Rb spin exchange. Computer-controlled valves allow polarized He3 gas to be transferred quickly between the optical pumping station and the spherical Pyrex target cell, which has Kapton film covering apertures for the passing beam and the scattering particles. The magnetic field required to maintain He3 polarization in the target cell is created with a compact, shielded sine-theta coil. Target gas polarimetry is accomplished using nuclear magnetic resonance and calibrated using the known analyzing power of α-He3 scattering.

  13. Virtual compton scattering at low energy and the generalized polarizabilities of the nucleon

    SciTech Connect

    Helene Fonvieille

    2003-10-01

    We present a particular kind of (e, e' p) experiments, which has opened a new field of investigation of nucleon structure in the last ten years. The exclusive photon electroproduction process p(e, e' p){gamma} is used to study Virtual Compton Scattering (VCS) off the proton: {gamma}*p {yields} {gamma}p. In the low energy domain, this process gives access to new observables called the Generalized Polarizabilities. They are fundamental properties of the nucleon, characterizing the deformation of its internal structure under an applied electromagnetic field. Dedicated experiments have been performed at MAMI, Jefferson Lab and MIT-Bates. This contribution summarizes the results obtained so far and future prospects in the field.

  14. Low energy pion-pion elastic scattering in the Sakai-Sugimoto model

    SciTech Connect

    Parthasarathy, R.; Viswanathan, K. S.

    2008-06-01

    We have considered the holographic large N{sub c} QCD model proposed by Sakai and Sugimoto and evaluated the non-Abelian DBI-action on the D8-brane up to ({alpha}{sup '}){sup 4} terms. Restricting to the pion sector, these corrections give rise to four derivative contact terms for the pion field. We derive the Weinberg's phenemenological Lagrangian. The coefficients of the four derivative terms are determined in terms of g{sub YM}{sup 2}. The low energy pion-pion scattering amplitudes are evaluated. Numerical results are presented with the choice of M{sub KK}=0.94 GeV and N{sub c}=11. The results are compared with the amplitudes calculated using the experimental phase shifts. The agreement with the experimental data is found to be satisfactory.

  15. High-energy electronic excitations in Sr2IrO4 observed by Raman scattering

    NASA Astrophysics Data System (ADS)

    Yang, Jhih-An; Huang, Yi-Ping; Hermele, Michael; Qi, Tongfei; Cao, Gang; Reznik, Dmitry

    2015-03-01

    The interplay between spin-orbit interaction, on-site coulomb correlation, crystal field splitting, and inter-site hopping leads to a novel insulating behavior in Sr2IrO4 as the realization of the Jeff = 1 / 2 state. We report results of a large-shift Raman scattering investigation of electronic excitations in Sr2IrO4. We found two high-energy excitations at 690 meV and 680 meV with A1 g and B1 g symmetry respectively. The two peaks have different temperature and Rh-doping dependences. Symmetry analysis of the dd transitions that contribute to Raman signals will also be presented. The observed peaks are consistent with the scenario of excitons associated with inter-site dd transitions without pseudospin-flip. NSF, DOE, and BES.

  16. Low-energy photodetachment of Ga- and elastic electron scattering from neutral Ga

    NASA Astrophysics Data System (ADS)

    Wang, Kedong; Zatsarinny, Oleg; Bartschat, Klaus

    2016-08-01

    We present a comprehensive study of the photodetachment of the negative gallium ion and elastic electron scattering from neutral Ga for photon and electron energies ranging from threshold to 12 eV. The calculations are carried out with the B -spline R -matrix method. A multiconfiguration Hartree-Fock method with nonorthogonal term-dependent orbitals is employed to generate accurate initial- and final-state wave functions. The close-coupling expansions include the 4 s 24 p n l (k l ) bound and continuum states of Ga and the 4 s -excited autoionizing states 4 s 4 p2 . The calculated photodetachment and elastic cross sections exhibit prominent resonance features. In order to clarify the origin of these resonances, the contributions of the major ionization channels to the partial cross sections are analyzed in detail.

  17. Fully microscopic description of elastic and inelastic scattering at intermediate incident energies

    NASA Astrophysics Data System (ADS)

    Minomo, Kosho; Kohno, Michio; Toyokawa, Masakazu; Yahiro, Masanobu; Ogata, Kazuyuki

    2016-06-01

    We aim for fully microscopic understanding of many-body nuclear reactions starting from two- and three-nucleon forces based on chiral effective field theory (Ch-EFT). We first construct a g-matrix with the nuclear forces based on Ch-EFT using Brueckner-Hartree-Fock theory, in which the three-nucleon force effects are represented through the density dependence of the g-matrix. Then, the folding model and microscopic coupled-channels method with the g-matrix are applied to nucleon-nucleus and nucleus-nucleus scattering at intermediate incident energies. This new microscopic framework well describes the elastic and inelastic cross sections with no ad-hoc parameters. In addition, the three-nucleon force and coupled-channels effects on many-body nuclear reactions are clarified.

  18. Medium-energy ion-scattering study of strained holmium silicide nanoislands grown on silicon (100)

    NASA Astrophysics Data System (ADS)

    Wood, T. J.; Eames, C.; Bonet, C.; Reakes, M. B.; Noakes, T. C. Q.; Bailey, P.; Tear, S. P.

    2008-07-01

    We have used medium-energy ion scattering (MEIS) to quantitatively analyze the structure of holmium silicide islands grown on the Si(100) surface. Structure fitting to the experimental data unambiguously shows that the tetragonal silicide phase is present and not the hexagonal phase, which is associated with the growth of nanowires at submonolayer coverages. Islands formed with a lower holmium coverage of 3 ML are also shown to be tetragonal, which suggests that the hexagonal structure is not a low coverage precursor to the growth of the tetragonal phase. MEIS simulations of large nanoislands, which include the effects of lateral strain relief, have been performed and these compare well with the experimental data.

  19. Elastic proton scattering at intermediate energies as a probe of the He,86 nuclear matter densities

    NASA Astrophysics Data System (ADS)

    Chung, Le Xuan; Kiselev, Oleg A.; Khoa, Dao T.; Egelhof, Peter

    2015-09-01

    The Glauber model analysis of the elastic He,86+p scattering data at energies around 700 MeV/nucleon, measured in two separate experiments at GSI-Darmstadt, has been carried out using several phenomenological parametrizations of the nuclear matter density. By taking into account the new data points measured at high-momentum transfer, the nuclear matter radii of ,8He6 have been accurately determined from the Glauber model analysis of the data, with the spin-orbital interaction explicitly taken into account. The well-known geometry for the core and dineutron halo has been used with the new parametrizations of the 6He density to extract the detailed information on the structure of 6He in terms of the core and dineutron halo radii. An enhanced sensitivity of the data measured at high-momentum transfer to the core part of the 6,8He densities has been found.

  20. Curve crossing for low-energy elastic scattering of He/+/ by Ne.

    NASA Technical Reports Server (NTRS)

    Bobbio, S. M.; Doverspike, L. D.; Champion, R. L.

    1973-01-01

    The perturbation seen in the experimental differential elastic-scattering cross section for the 40-eV He/+/ + Ne system has been attributed to a single crossing of two intermolecular potential-energy curves. A new theoretical treatment of the curve-crossing problem, namely, that of Delos and Thorson, is employed to obtain the crossing probabilities and phases associated with the crossing. These are determined by utilizing ab initio potentials involved in the crossing and are further used in a partial-wave calculation of the cross section, which is compared with our experiment. The origin of the oscillatory structure observed in the differential cross section is discussed in semiclassical terms by defining the problem in terms of two pseudo-deflection-functions. A rainbow effect is shown to be related to a particular feature (a maximum rather than a minimum) of these deflection functions.

  1. Scattering of NH3 and ND3 with rare gas atoms at low collision energy.

    PubMed

    Loreau, J; van der Avoird, A

    2015-11-14

    We present a theoretical study of elastic and rotationally inelastic collisions of NH3 and ND3 with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm(-1). We focus on collisions in which NH3 is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an experimental context as it can be trapped electrostatically and Stark-decelerated. We discuss the presence of resonances in the elastic and inelastic cross sections, as well as the trends in the inelastic cross sections along the rare gas series and the differences between NH3 and ND3 as a colliding partner. We also demonstrate the importance of explicitly taking into account the umbrella (inversion) motion of NH3 in order to obtain accurate scattering cross sections at low collision energy. Finally, we investigate the possibility of sympathetic cooling of ammonia using cold or ultracold rare gas atoms. We show that some systems exhibit a large ratio of elastic to inelastic cross sections in the cold regime, which is promising for sympathetic cooling experiments. The close-coupling calculations are based on previously reported ab initio potential energy surfaces for NH3-He and NH3-Ar, as well as on new, four-dimensional, potential energy surfaces for the interaction of ammonia with Ne, Kr, and Xe, which were computed using the coupled-cluster method and large basis sets. We compare the properties of the potential energy surfaces corresponding to the interaction of ammonia with the various rare gas atoms. PMID:26567658

  2. Compton scattering for spectroscopic detection of ultra-fast, high flux, broad energy range X-rays

    SciTech Connect

    Cipiccia, S.; Wiggins, S. M.; Brunetti, E.; Vieux, G.; Yang, X.; Welsh, G. H.; Anania, M.; Islam, M. R.; Ersfeld, B.; Jaroszynski, D. A.; Maneuski, D.; Montgomery, R.; Smith, G.; Hoek, M.; Hamilton, D. J.; Shea, V. O.; Issac, R. C.; Lemos, N. R. C.; Dias, J. M.; and others

    2013-11-15

    Compton side-scattering has been used to simultaneously downshift the energy of keV to MeV energy range photons while attenuating their flux to enable single-shot, spectrally resolved, measurements of high flux X-ray sources to be undertaken. To demonstrate the technique a 1 mm thick pixelated cadmium telluride detector has been used to measure spectra of Compton side-scattered radiation from a Cobalt-60 laboratory source and a high flux, high peak brilliance X-ray source of betatron radiation from a laser-plasma wakefield accelerator.

  3. Demonstration of energy-coded Compton scatter tomography with fan beams for one-sided inspection

    NASA Astrophysics Data System (ADS)

    Evans, Brian L.; Martin, Jeffrey B.; Burggraf, Larry W.; Roggemann, M. C.; Hangartner, T. N.

    2002-03-01

    An instrument is demonstrated whereby radiographic images of a sample's electron density are compiled from the information encoded in the energy spectra of gamma rays backscattered from one side of the sample. It is assumed that access is restricted to only one surface of the object under inspection. Use of energy coding allows imaging in a fan beam rather than independent interrogation of individual volume elements. The Multiplexed Compton Scatter Tomograph instrument consists of an array of high-energy-resolution detectors and fan beam collimators. Instrument signals are converted to electron density images using a penalized weighted least squares image reconstruction algorithm coupled with a deterministic system model that includes effects of Doppler broadening. The proof-of-principle instrument is demonstrated on aluminum samples. In an 8 mm thick sample with a 4 mm void in its center, contrast recovery of 90% is achieved. In a 10 mm thick sample with a 3 mm void at the back about 85% of the contrast is recovered.

  4. Simultaneous small- and wide-angle scattering at high X-ray energies.

    PubMed

    Daniels, J E; Pontoni, D; Hoo, Rui Ping; Honkimäki, V

    2010-07-01

    Combined small- and wide-angle X-ray scattering (SAXS/WAXS) is a powerful technique for the study of materials at length scales ranging from atomic/molecular sizes (a few angstroms) to the mesoscopic regime ( approximately 1 nm to approximately 1 microm). A set-up to apply this technique at high X-ray energies (E > 50 keV) has been developed. Hard X-rays permit the execution of at least three classes of investigations that are significantly more difficult to perform at standard X-ray energies (8-20 keV): (i) in situ strain analysis revealing anisotropic strain behaviour both at the atomic (WAXS) as well as at the mesoscopic (SAXS) length scales, (ii) acquisition of WAXS patterns to very large q (>20 A(-1)) thus allowing atomic pair distribution function analysis (SAXS/PDF) of micro- and nano-structured materials, and (iii) utilization of complex sample environments involving thick X-ray windows and/or samples that can be penetrated only by high-energy X-rays. Using the reported set-up a time resolution of approximately two seconds was demonstrated. It is planned to further improve this time resolution in the near future. PMID:20567079

  5. Search for a new charged heavy vector boson decaying to an electron-neutrino pair in p anti-p collisions at s**(1/2) = 1.96 TeV

    SciTech Connect

    Kim, Jieun

    2005-06-01

    We present results on a search for a heavy charged vector boson, W', decaying to an electron-neutrino pair in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 205 pb{sup -1}. We found no evidence of this decay channel, and set 95% confidence level limits on the production cross section times branching fraction assuming the light neutrino. We also set the limit on the W' boson mass at M{sub W'} > 788 GeV/c{sup 2}, assuming the standard model strength couplings.

  6. Neutron Scattering Cross Sections for Natural Carbon in the Energy Range 2-133 keV

    SciTech Connect

    Gritzay, O; Gnidak, M; Kolotyi, V; Korol, O; Razbudey, V; Venedyktov, V; Richardson, J H; Sale, K

    2006-06-14

    Natural carbon is well known as reactor structure material and at the same time as one of the most important neutron scattering standards, especially at energies less than 2 MeV, where the neutron total and neutron scattering cross sections are essentially identical. The best neutron total cross section experimental data for natural carbon in the range 1-500 keV have uncertainties of 1-4%. However, the difference between these data and those based on R-matrix analysis and used in the ENDF libraries is evident, especially in the energy range 1-60 keV. Experimental data for total scattering neutron cross sections for this element in the energy range 1-200 keV are scanty. The use of the technique of neutron filtered beams developed at the Kyiv Research Reactor makes it possible to reduce the uncertainty of the experimental data and to measure the neutron scattering cross sections on natural carbon in the energy range 2-149 keV with accuracies of 3-6%. Investigations of the neutron scattering cross section on carbon were carried out using 5 filters with energies 2, 3.5, 24, 54 and 133 keV. The neutron scattering cross sections were measured using a detector system covering nearly 2{pi}. The detector consisting of {sup 3}He counters (58 units), was located just above the carbon samples. The {sup 3}He counters (CHM-37, 7 atm, diameter =18 mm, L=50 cm) are placed in five layers (12 or 11 in each layer). To determine the neutron scattering cross section on carbon the relative method of measurement was used. The isotope {sup 208}Pb was used as the standard. The normalization factor, which is a function of detector efficiency, thickness of the carbon samples, thickness of the {sup 208}Pb sample, geometry, etc., for each sample and for each filter energy has been obtained through Monte Carlo calculations by means of the MCNP4C code. The results of measurements of the neutron scattering cross sections at reactor neutron filtered beams with energies in the range 2-133 keV on

  7. Surface structure and composition determination by low-energy electron scattering and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Sun, Jiebing

    This thesis reports on surface and surface alloy structural and compositional determination with low-energy electron scattering and Monte Carlo simulations. Low-energy electron diffraction (LEED) technique and the newly developed low-energy electron microscopy (LEEM) IV technique are used to measure the electron scattering intensity spectra and dynamical multiple scattering analysis is performed to optimize the surface structural and non-structural parameters via comparison between the experimental spectra and calculated ones. My work focuses on the following four surface systems. (111), (110) and (001) surface structures of the semimetal bismuth are determined with LEED. The unreconstructed (1x1) structure is revealed for all three surfaces. The interlayer spacings for several outermost layers are resolved. All results agree with those obtained by first-principles calculations. The Debye temperatures for the Bi(111) and Bi(110) surface are found to be lower than that of the Bi bulk. In conjunction with the LEED technique, scanning tunneling microscopy (STM) observation is performed on the Bi(001) surface. Surface topology images show dominant bilayer steps and no single layer step. The newly developed LEEM-IV technique is used to investigate the PdCu surface alloy on the substrate Cu(001). Studies include quantifying the temporal evolution of Pd concentration on the Cu(001) terrace, mapping the 3D heterogeneous surface chemical composition, and identifying a step-overgrowth thin film growth mechanism. It is found that, at the initial deposition stages, Pd atoms reside in the second layer at the sample temperature of 473 K, and the Pd concentration increases exponentially with time. The heterogeneous structure and composition near the steps are found to be a result of the step-overgrowth. We highlight the LEEM-IV technique which provides a high lateral resolution at surfaces. We demonstrate a 3D profile of Pd concentration in the surface region by using the LEEM

  8. Simulation of 12C+12C elastic scattering at high energy by using the Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Guo, Chen-Lei; Zhang, Gao-Long; Tanihata, I.; Le, Xiao-Yun

    2012-03-01

    The Monte Carlo method is used to simulate the 12C+12C reaction process. Taking into account the size of the incident 12C beam spot and the thickness of the 12C target, the distributions of scattered 12C on the MWPC and the CsI detectors at a detective distance have been simulated. In order to separate elastic scattering from the inelastic scattering with 4.4 MeV excited energy, we set several variables: the kinetic energy of incident 12C, the thickness of the 12C target, the ratio of the excited state, the wire spacing of the MWPC, the energy resolution of the CsI detector and the time resolution of the plastic scintillator. From the simulation results, the preliminary establishment of the experiment system can be determined to be that the beam size of the incident 12C is phi5 mm, the incident kinetic energy is 200-400 A MeV, the target thickness is 2 mm, the ratio of the excited state is 20%, the flight distance of scattered 12C is 3 m, the energy resolution of the CsI detectors is 1%, the time resolution of the plastic scintillator is 0.5%, and the size of the CsI detectors is 7 cm×7 cm, and we need at least 16 CsI detectors to cover a 0° to 5° angular distribution.

  9. High-brightness, high-energy radiation generation from non-linear Thomson scattering of laser wakefield accelerated electrons

    NASA Astrophysics Data System (ADS)

    Schumaker, W.; Zhao, Z.; Thomas, A. G. R.; Krushelnick, K.; Sarri, G.; Corvan, D.; Zepf, M.; Cole, J.; Mangles, S. P. D.; Najmudin, Z.

    2014-10-01

    To date, all-optical sources of high-energy (>MeV) photons have only been reported in the linear (a0 < 1) regime of Thomson scattering using laser wakefield acceleration (LWFA). We present novel results of high-brightness, high-energy photons generated via non-linear Thomson scattering using the two-beam Astra-Gemini laser facility. With one 300 TW beam, electrons were first accelerated to 500 MeV energies inside gas cells through the process of LWFA. A second 300 TW laser pulse focused to a0 = 2 was subsequently scattered off these electrons, resulting in a highly directional, small source size, and short pulse beam of photons with >10 MeV energies. The photon beam was propagated through a low- Z converter and produced Compton-scattered electrons that were spectrally measured by magnetic deflection and correlated with the incident photons. The measured photon yield at 15 MeV was 2 ×106 photons/MeV and, when coupled with the small source size, divergence, and pulse duration, results in a record peak brightness of 2 ×1019 photons/s/mm2/mrad2/0.1%bandwidth at 15 MeV photon energy. Current Affiliation: Stanford University/SLAC National Accelerator Laboratory.

  10. QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG

    SciTech Connect

    Adams, T.; Batra, P.; Bugel, Leonard G.; Camilleri, Leslie Loris; Conrad, Janet Marie; de Gouvea, A.; Fisher, Peter H.; Formaggio, Joseph Angelo; Jenkins, J.; Karagiorgi, Georgia S.; Kobilarcik, T.R.; /Fermilab /Texas U.

    2009-06-01

    We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics.

  11. Electron hole pair mediated vibrational excitation in CO scattering from Au(111): Incidence energy and surface temperature dependence

    SciTech Connect

    Shirhatti, Pranav R.; Werdecker, Jörn; Golibrzuch, Kai; Wodtke, Alec M.; Bartels, Christof

    2014-09-28

    We investigated the translational incidence energy (E{sub i}) and surface temperature (T{sub s}) dependence of CO vibrational excitation upon scattering from a clean Au(111) surface. We report absolute v = 0 → 1 excitation probabilities for E{sub i} between 0.16 and 0.84 eV and T{sub s} between 473 and 973 K. This is now only the second collision system where such comprehensive measurements are available – the first is NO on Au(111). For CO on Au(111), vibrational excitation occurs via direct inelastic scattering through electron hole pair mediated energy transfer – it is enhanced by incidence translation and the electronically non-adiabatic coupling is about 5 times weaker than in NO scattering from Au(111). Vibrational excitation via the trapping desorption channel dominates at E{sub i} = 0.16 eV and quickly disappears at higher E{sub i}.

  12. High-energy scatterings in infinite-derivative field theory and ghost-free gravity

    NASA Astrophysics Data System (ADS)

    Talaganis, Spyridon; Mazumdar, Anupam

    2016-07-01

    In this paper, we will consider scattering diagrams in the context of infinite-derivative theories. First, we examine a finite-order, higher-derivative scalar field theory and find that we cannot eliminate the growth of scattering diagrams for large external momenta. Then, we employ an infinite-derivative scalar toy model and obtain that the external momentum dependence of scattering diagrams is convergent as the external momenta become very large. In order to eliminate the external momentum growth, one has to dress the bare vertices of the scattering diagrams by considering renormalised propagator and vertex loop corrections to the bare vertices. Finally, we investigate scattering diagrams in the context of a scalar toy model which is inspired by a ghost-free and singularity-free infinite-derivative theory of gravity, where we conclude that infinite derivatives can eliminate the external momentum growth of scattering diagrams and make the scattering diagrams convergent in the ultraviolet.

  13. X-ray scatter correction for dual-energy x-ray absorptiometry: compensation of patient's lean/fat composition

    NASA Astrophysics Data System (ADS)

    Dinten, Jean-Marc; Darboux, Michel; Bordy, Thomas; Robert-Coutant, Christine; Gonon, Georges

    2004-05-01

    At CEA-LETI, a DEXA approach for systems using a digital 2D radiographic detector has been developed. It relies on an original X-rays scatter management method, based on a combined use of an analytical model and of scatter calibration data acquired through different thicknesses of Lucite slabs. Since Lucite X-rays interaction properties are equivalent to fat, the approach leads to a scatter flux map representative of a 100% fat region. However, patients" soft tissues are composed of lean and fat. Therefore, the obtained scatter map has to be refined in order to take into account the various fat ratios that can present patients. This refinement consists in establishing a formula relating the fat ratio to the thicknesses of Low and High Energy Lucite slabs leading to same signal level. This proportion is then used to compute, on the basis of X-rays/matter interaction equations, correction factors to apply to Lucite equivalent X-rays scatter map. Influence of fat ratio correction has been evaluated, on a digital 2D bone densitometer, with phantoms composed of a PVC step (simulating bone) and different Lucite/water thicknesses as well as on patients. The results show that our X-rays scatter determination approach can take into account variations of body composition.

  14. Inline Modeling of Cross-Beam Energy Transfer and Raman Scattering in NIF Hohlraums

    NASA Astrophysics Data System (ADS)

    Strozzi, David; Bailey, D. S.; Thomas, C. A.; Sepke, S. M.; Kerbel, G. D.; Michel, P.; Divol, L.; Jones, O. S.

    2015-11-01

    Inline models of cross-beam energy transfer (CBET) and stimulated Raman Scattering (SRS) have been added to the radiation-hydrodynamics codes Hydra and Lasnex. Both processes are important in hohlraums with high gas fill density, particularly for implosion symmetry. Coupled-mode equations are solved along laser ray paths for both models. The inline model shows the SRS gain rate exceeds that of SRS light absorption along most of the laser ray path, and most SRS light escapes the target. Most SRS-driven Langmuir wave power is deposited slightly inside the laser entrance hole (LEH), which reduces how much inner-beam power reaches the equator. This also makes the LEH hotter, which affects CBET. Compared to removing SRS power from the incident laser, the inline SRS model does not change total x-ray drive but makes the drive stronger from the poles than the equatorial waist. This reduces the need to artificially clamp CBET in order to match implosion shape data, which has historically been needed for high gas fill hohlraums. We are applying the models to a set of NIF shots with varying gas fill densities. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  15. Spin correlation parameter and analyzing power in n - p elastic scattering at intermediate energies

    SciTech Connect

    Bandyopadhyay, D. ); Abegg, R.; Ahmad, M.; Birchall, J.; Chantziantoniou, K.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Healey, D.C.; Lapointe, C.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Page, S.A.; Ramsay, W.D.; Rodning, N.L.; Roy, G.; van Oers, W.T.H.; Wait, G.D.; Watson, J.W.; Ye, Y.

    1989-12-01

    In order to improve existing {ital I}=0 phase shift solutions, the spin correlation parameter {ital A}{sub {ital NN}} and the analyzing powers {ital A}{sub 0{ital N}} and {ital A}{sub {ital N}0} have been measured in {ital n}-{ital p} elastic scattering over an angular range of 50{degree}--150{degree} (c.m.) at three neutron energies (220, 325, and 425 MeV) to an absolute accuracy of {plus minus}0.03. The data have a profound effect on various phase parameters, particularly the {sup 1}P{sub 1}, {sup 3}D{sub 2}, and {epsilon}{sub 1} phase parameters which in some cases change by almost a degree. With the exception of the highest energy, the data support the predictions of the latest version of the Bonn potential. Also, the analyzing power data ({ital A}{sub 0{ital N}} and {ital A}{sub {ital N}0}) measured at 477 MeV in a different experiment over a limited angular range (60{degree}--80{degree} (c.m.)) are reported here.

  16. High energy-resolution zero-degree facility for light-ion scattering and reactions at iThemba LABS

    NASA Astrophysics Data System (ADS)

    Neveling, R.; Fujita, H.; Smit, F. D.; Adachi, T.; Berg, G. P. A.; Buthelezi, E. Z.; Carter, J.; Conradie, J. L.; Couder, M.; Fearick, R. W.; Förtsch, S. V.; Fourie, D. T.; Fujita, Y.; Görres, J.; Hatanaka, K.; Jingo, M.; Krumbholz, A. M.; Kureba, C. O.; Mira, J. P.; Murray, S. H. T.; von Neumann-Cosel, P.; O'Brien, S.; Papka, P.; Poltoratska, I.; Richter, A.; Sideras-Haddad, E.; Swartz, J. A.; Tamii, A.; Usman, I. T.; van Zyl, J. J.

    2011-10-01

    The setup and experimental techniques for measurements of zero-degree inelastic scattering and reactions involving light ions with the K=600 magnetic spectrometer at iThemba LABS are described. Measurements were performed for inelastic proton scattering at an incident energy of 200 MeV for targets ranging from 27Al to 208Pb. An energy-resolution of 45 keV (FWHM) was achieved by utilizing the faint-beam dispersion-matching technique. A background subtraction procedure was applied and allowed for the extraction of excitation energy spectra with low background. Measurements of the (p,t) reaction at zero degrees for Ep=100 and 200 MeV benefited from the difference in magnetic rigidity between the reaction products and the beam particles, resulting in background-free spectra with an excitation energy-resolution of 32 and 48 keV (FWHM), respectively, and a scattering angle resolution of 0.55° (FWHM). The addition of Double Sided Silicon Strip Detectors (DSSSD) at backward scattering angles allowed for coincident measurements of particle-decay of states excited in the (p,t) reaction at Ep=200 MeV.

  17. Inelastic scattering measurements of low energy x-ray photons by organics, soil, water, wood, and metals

    NASA Astrophysics Data System (ADS)

    Paki Amouzou, P.; Gertsenshteyn, M.; Jannson, T.; Shnitser, P.; Savant, G.

    2006-08-01

    The angular distribution of the inelastic scattering of photons at low energies (<=80 KeV) has been measured in organic material, soil, rocks, wood, steel sheet, and water. The measurements have been performed under air inside an X-ray shield cabinet using X-rays tube as a photon source and a thermoelectrically cooled CdTe detector. Measurements have been taken for both single and combined materials. The contributions of inelastic scattering of photons for the lower Z material in a given configuration have been extracted. The measured signal is primarily Compton scattering. The measured inelastic scattering contributions were compared with the calculated inelastic scattering cross sections according to the Klein-Nishina theory, updated to include a practical energy distribution of an X-ray tube beam. Relatively good agreement was found for all targets under investigation. The slight discrepancy is attributed to photoelectric effect and sample configuration. Present results may act as a guide for optimization of X-ray imaging sensors and in particular of those based on lobster eye X-ray optics suitable for cargo inspection, improvised explosives detection, non-destructive evaluation, and medical imaging.

  18. Neutrino-nucleus scattering reexamined: Quasielastic scattering and pion production entanglement and implications for neutrino energy reconstruction

    SciTech Connect

    Leitner, T.; Mosel, U.

    2010-06-15

    We apply the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) model to questions relevant to current and future long-baseline neutrino experiments, and we address in particular the relevance of charged-current reactions for neutrino-disappearance experiments. A correct identification of charged-current quasielastic (CCQE) events--which is the signal channel in oscillation experiments--is relevant for neutrino energy reconstruction and thus for the oscillation result. We show that about 20% of the quasielastic cross section is misidentified in present-day experiments and has to be corrected for by means of event generators. Furthermore, we show that a significant part of 1pi{sup +} (> 40%) events is misidentified as CCQE events, mainly caused by pion absorption in the nucleus. We also discuss the dependence of both of these numbers on experimental detection thresholds. We further investigate the influence of final-state interactions on the neutrino energy reconstruction.

  19. Inclusion of electron correlation for the target wave function in low- to intermediate-energy e-N2 scattering

    NASA Technical Reports Server (NTRS)

    Weatherford, C. A.; Brown, F. B.; Temkin, A.

    1987-01-01

    In a recent calculation, an exact exchange method was developed for use in the partial-differential-equation approach to electron-molecule scattering and was applied to e-N2 scattering in the fixed-nuclei approximation with an adiabatic polarization potential at low energies (0-10 eV). Integrated elastic cross sections were calculated and found to be lower than experiment at energies both below and above the Pi(g) resonance. It was speculated at that time that improved experimental agreement could be obtained if a correlated target representation were used in place of the uncorrelated one. The present paper implements this suggestion and demonstrates the improved agreement. These calculations are also extended to higher energies (0-30 eV) so asd to include the Sigma(u) resonance. Some discrepancies among the experiments and between experiment and the various calculations at very low energy are noted.

  20. Low-energy ionization yield in liquid argon for a coherent neutrino-nucleus scatter detector

    NASA Astrophysics Data System (ADS)

    Foxe, Michael P.

    A mode of interaction predicted by the Standard Model of particle physics, but not yet observed, is coherent neutrino-nucleus scattering (CNNS). CNNS results from the neutrino (or antineutrino) scattering coherently with the entire nucleus rather than a single nucleon. The leading challenge in detecting CNNS is the resulting sub-keV nuclear recoil energies, producing little ionization in the detector medium. In order to detect the CNNS interaction, it is beneficial to first measure the nuclear ionization yield for the chosen detector medium. The ionization yield represents the expected number of electrons produced by a nuclear recoil, and it depends both on the recoil energy and on the detector medium in which the recoil occurs. Additionally, the ionization yield depends on the applied electron drift electric field, and for this reason it should be measured directly in the detector type anticipated for future CNNS measurements. This dissertation is focused on making the prediction and measurement of the ionization yield in LAr using a dual-phase Ar detector. Due to the complexity of measuring the ionization yield at various energies, it is beneficial to also construct a predictive model for the ionization yield. In this dissertation, the prediction of the ionization yield is made on the basis of a simulation of a two-stage process. The number of ionizations generated from Ar recoil of a given energy is simulated using a Monte Carlo atomic collision model, along with the cross sections for ionization and excitation in Ar + Ar collisions. After the electrons are generated, a fraction of them recombine with the initially generated ion cloud. The electron recombination fraction is simulated by assigning the emitted electrons either 1 or 10 eV of initial kinetic energy and transporting the electrons under the influence of Coulomb forces of the ion cloud and an applied external electric field. The simulation predicts the energy dependent ionization yield, with a value of

  1. Electron-helium and electron-neon scattering cross sections at low electron energies using a photoelectron source

    NASA Technical Reports Server (NTRS)

    Kumar, Vijay; Subramanian, K. P.; Krishnakumar, E.

    1987-01-01

    Absolute electron-helium and electron-neon scattering cross sections have been measured at low electron energies using the powerful technique of photoelectron spectroscopy. The measurements have been carried out at 17 electron energies varying from 0.7 to 10 eV with an accuracy of + or - 2.7 percent. The results obtained in the present work have been compared with other recent measurement and calculations.

  2. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    SciTech Connect

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-15

    We have determined ''effective'' Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  3. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-01

    We have determined "effective" Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  4. Observations of the scatter-free solar-flare electrons in the energy range 20-1000 keV

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Fisk, L. A.; Lin, R. P.

    1971-01-01

    Observations of the scatter-free electron events from solar active region McMath No. 8905 are presented. The measurements were made on Explorer 33 satellite. The data show that more than 80% of the electrons from these events undergo no or little scattering and that these electrons travel only approximately 1.5 a.u. between the sun and the earth. The duration of these events cannot be accounted fully by velocity dispersion alone. It is suggested that these electrons could be continuously injected into interplanetary medium for a time interval of approximately 2 to 3 minutes. Energy spectra of these electrons are discussed.

  5. The HCO{sup +}–H{sub 2} van der Waals interaction: Potential energy and scattering

    SciTech Connect

    Massó, H.; Wiesenfeld, L.

    2014-11-14

    We compute the rigid-body, four-dimensional interaction potential between HCO{sup +} and H{sub 2}. The ab initio energies are obtained at the coupled-cluster single double triple level of theory, corrected for Basis Set Superposition Errors. The ab initio points are fit onto the spherical basis relevant for quantum scattering. We present elastic and rotationally inelastic coupled channels scattering between low lying rotational levels of HCO{sup +} and para-/ortho-H{sub 2}. Results are compared with similar earlier computations with He or isotropic para-H{sub 2} as the projectile. Computations agree with earlier pressure broadening measurements.

  6. Microscopic study of neutron elastic scattering from {sup 12}C, {sup 40}Ca, and {sup 208}Pb at intermediate energies

    SciTech Connect

    Alvi, M. A.; Arafah, M. R.; Madani, J. H.; Ahmad, I.

    2009-02-15

    Recent neutron elastic scattering differential cross section data for {sup 12}C, {sup 40}Ca, and {sup 208}Pb at several energies from 65 to 225 MeV have been analyzed using Glauber multiple scattering model, suitably modified to enlarge angular range of validity. The center of mass and Pauli pair correlations have been considered. The effect of the phase variation of the NN scattering amplitude on the calculated cross sections has been studied. A medium modification of the 'elementary' NN interaction is also considered. The neutron differential cross sections have been calculated using the phenomenological and the recently proposed semiphenomenological neutron and proton target densities so as to check the validity of the semiphenomenological density model. We found that our method of analysis gives a very good description of the experimental data.

  7. Monte Carlo simulation and parameterized treatment on the effect of nuclear elastic scattering in high-energy proton radiography

    NASA Astrophysics Data System (ADS)

    Xu, Hai-Bo; Zheng, Na

    2015-07-01

    A version of Geant4 has been developed to treat high-energy proton radiography. This article presents the results of calculations simulating the effects of nuclear elastic scattering for various test step wedges. Comparisons with experimental data are also presented. The traditional expressions of the transmission should be correct if the angle distribution of the scattering is Gaussian multiple Coulomb scattering. The mean free path (which depends on the collimator angle) and the radiation length are treated as empirical parameters, according to transmission as a function of thickness obtained by simulations. The results can be used in density reconstruction, which depends on the transmission expressions. Supported by NSAF (11176001) and Science and Technology Developing Foundation of China Academy of Engineering Physics (2012A0202006)

  8. The influence of triple energy window scatter correction on activity quantification for 1 7 7Lu molecular radiotherapy

    NASA Astrophysics Data System (ADS)

    Robinson, Andrew P.; Tipping, Jill; Cullen, David M.; Hamilton, David

    2016-07-01

    Accurate activity quantification is the foundation for all methods of radiation dosimetry for molecular radiotherapy (MRT). The requirements for patient-specific dosimetry using single photon emission computed tomography (SPECT) are challenging, particularly with respect to scatter correction. In this paper data from phantom studies, combined with results from a fully validated Monte Carlo (MC) SPECT camera simulation, are used to investigate the influence of the triple energy window (TEW) scatter correction on SPECT activity quantification for {{}1 7 7} Lu MRT. Results from phantom data show that; (1) activity quantification for the total counts in the SPECT field-of-view demonstrates a significant overestimation in total activity recovery when TEW scatter correction is applied at low activities (≤slant 200 MBq). (2) Applying the TEW scatter correction to activity quantification within a volume-of-interest with no background activity provides minimal benefit. (3) In the case of activity distributions with background activity, an overestimation of recovered activity of up to 30% is observed when using the TEW scatter correction. Data from MC simulation were used to perform a full analysis of the composition of events in a clinically reconstructed volume of interest. This allowed, for the first time, the separation of the relative contributions of partial volume effects (PVE) and inaccuracies in TEW scatter compensation to the observed overestimation of activity recovery. It is shown, that even with perfect partial volume compensation, TEW scatter correction can overestimate activity recovery by up to 11%. MC data is used to demonstrate that even a localized and optimized isotope-specific TEW correction cannot reflect a patient specific activity distribution without prior knowledge of the complete activity distribution. This highlights the important role of MC simulation in SPECT activity quantification.

  9. The influence of triple energy window scatter correction on activity quantification for (1 7 7)Lu molecular radiotherapy.

    PubMed

    Robinson, Andrew P; Tipping, Jill; Cullen, David M; Hamilton, David

    2016-07-21

    Accurate activity quantification is the foundation for all methods of radiation dosimetry for molecular radiotherapy (MRT). The requirements for patient-specific dosimetry using single photon emission computed tomography (SPECT) are challenging, particularly with respect to scatter correction. In this paper data from phantom studies, combined with results from a fully validated Monte Carlo (MC) SPECT camera simulation, are used to investigate the influence of the triple energy window (TEW) scatter correction on SPECT activity quantification for [Formula: see text]Lu MRT. Results from phantom data show that; (1) activity quantification for the total counts in the SPECT field-of-view demonstrates a significant overestimation in total activity recovery when TEW scatter correction is applied at low activities ([Formula: see text]200 MBq). (2) Applying the TEW scatter correction to activity quantification within a volume-of-interest with no background activity provides minimal benefit. (3) In the case of activity distributions with background activity, an overestimation of recovered activity of up to 30% is observed when using the TEW scatter correction. Data from MC simulation were used to perform a full analysis of the composition of events in a clinically reconstructed volume of interest. This allowed, for the first time, the separation of the relative contributions of partial volume effects (PVE) and inaccuracies in TEW scatter compensation to the observed overestimation of activity recovery. It is shown, that even with perfect partial volume compensation, TEW scatter correction can overestimate activity recovery by up to 11%. MC data is used to demonstrate that even a localized and optimized isotope-specific TEW correction cannot reflect a patient specific activity distribution without prior knowledge of the complete activity distribution. This highlights the important role of MC simulation in SPECT activity quantification. PMID:27351914

  10. Communication: Energy transfer and reaction dynamics for DCl scattering on Au(111): An ab initio molecular dynamics study.

    PubMed

    Kolb, Brian; Guo, Hua

    2016-07-01

    Scattering and dissociative chemisorption of DCl on Au(111) are investigated using ab initio molecular dynamics with a slab model, in which the top two layers of Au are mobile. Substantial kinetic energy loss in the scattered DCl is found, but the amount of energy transfer is notably smaller than that observed in the experiment. On the other hand, the dissociative chemisorption probability reproduces the experimental trend with respect to the initial kinetic energy, but is about one order of magnitude larger than the reported initial sticking probability. While the theory-experiment agreement is significantly improved from the previous rigid surface model, the remaining discrepancies are still substantial, calling for further scrutiny in both theory and experiment. PMID:27394092

  11. Communication: Energy transfer and reaction dynamics for DCl scattering on Au(111): An ab initio molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Kolb, Brian; Guo, Hua

    2016-07-01

    Scattering and dissociative chemisorption of DCl on Au(111) are investigated using ab initio molecular dynamics with a slab model, in which the top two layers of Au are mobile. Substantial kinetic energy loss in the scattered DCl is found, but the amount of energy transfer is notably smaller than that observed in the experiment. On the other hand, the dissociative chemisorption probability reproduces the experimental trend with respect to the initial kinetic energy, but is about one order of magnitude larger than the reported initial sticking probability. While the theory-experiment agreement is significantly improved from the previous rigid surface model, the remaining discrepancies are still substantial, calling for further scrutiny in both theory and experiment.

  12. Elastic scattering at 7 TeV and high-energy cross section for cosmic ray studies

    NASA Astrophysics Data System (ADS)

    Wibig, T.

    2012-08-01

    The recent measurements of the elastic cross section by the TOTEM Collaboration together with the first estimations of the inelastic cross sections by other LHC detectors are used to test the simplest version of the geometrical model of the proton-proton scattering. We show that the description found for lower energy data, with the modest adjustment of the model parameter extrapolation, could be, in principle, used to describe the LHC measurement and to predict the cross sections in very high energy cosmic ray domain. However, the shape of the first elastic dip in the elastic differential scattering cross section suggests that the ratio of the real to the imaginary part of the elastic amplitude falls rather fast and the analysis of the elastic cross-section fraction suggests that the geometrical picture and scaling of the proton-proton collision should be modified when entering the ultrahigh-energy domain.

  13. Analysis of experimental data on neutron-proton scattering in the energy range between 0 and 150 keV

    SciTech Connect

    Babenko, V. A. Petrov, N. M.

    2009-04-15

    Experimental data on neutron-proton scattering in the energy range between 0 and 150 keV are analyzed by using various sets of effective-range parameters. It is shown that, in contrast to the parameters corresponding to the phase shifts of a Nijmegen group, the parameters corresponding to the experimental phase shifts reported by a group from George Washington University (GWU group) lead to very good agreement between the calculated cross sections and their experimental counterparts in the energy region under consideration. On the basis of the experimental value of the cross section for neutron-proton scattering at an energy of 2 keV, the total cross section for neutron-proton scattering at zero energy was found to be {sigma}{sub 0} = 20.428(16) b, which is in very good agreement with a value of {sigma}{sub 0} = 20.423(9) b, which was obtained as the weighted mean of the cross sections presented by Houke and Hurst. It is shown that, in the energy region around several tens of keV units, the effective-range parameters matched with Dilg's cross-section value of {sigma}{sub 0} = 20.491(14) b lead to calculated cross sections whose values are in excess of their experimental counterparts.

  14. Analysis of experimental data on neutron-proton scattering in the energy range between 0 and 150 keV

    NASA Astrophysics Data System (ADS)

    Babenko, V. A.; Petrov, N. M.

    2009-04-01

    Experimental data on neutron-proton scattering in the energy range between 0 and 150 keV are analyzed by using various sets of effective-range parameters. It is shown that, in contrast to the parameters corresponding to the phase shifts of a Nijmegen group, the parameters corresponding to the experimental phase shifts reported by a group from George Washington University (GWU group) lead to very good agreement between the calculated cross sections and their experimental counterparts in the energy region under consideration. On the basis of the experimental value of the cross section for neutron—proton scattering at an energy of 2 keV, the total cross section for neutron-proton scattering at zero energy was found to be σ 0 = 20.428(16) b, which is in very good agreement with a value of σ 0 = 20.423(9) b, which was obtained as the weighted mean of the cross sections presented by Houke and Hurst. It is shown that, in the energy region around several tens of keV units, the effective-range parameters matched with Dilg’s cross-section value of σ 0 = 20.491(14) b lead to calculated cross sections whose values are in excess of their experimental counterparts.

  15. Geometries and focal properties of two electron-lens systems useful in low-energy electron or ion scattering

    NASA Technical Reports Server (NTRS)

    Chutjian, A.

    1979-01-01

    Geometries and focal properties are given for two types of electron-lens system commonly needed in electron scattering. One is an electron gun that focuses electrons from a thermionic emitter onto a fixed point (target) over a wide range of final energies. The other is an electron analyzer system that focuses scattered electrons of variable energy onto a fixed position (e.g., the entrance plane of an analyzer) at fixed energy with a zero final beam angle. Analyzer-system focusing properties are given for superelastically, elastically, and inelastically scattered electrons. Computer calculations incorporating recent accurate tube-lens focal properties are used to compute lens voltages, locations and diameters of all pupils and windows, filling factors, and asymptotic rays throughout each lens system. Focus voltages as a function of electron energy and energy change are given, and limits of operation of each system discussed. Both lens systems have been in routine use for several years, and good agreement has been consistently found between calculated and operating lens voltages.

  16. Low-energy positron scattering from DNA nucleobases: the effects from permanent dipoles

    NASA Astrophysics Data System (ADS)

    Franz, Jan; Gianturco, Francesco Antonio

    2014-10-01

    Ab initio quantum calculations for low-energy positron scattering from gas-phase isolated molecular nucleobases which are part of the DNA structure are presented and discussed over the range of 1 eV to 25 eV. The calculations report the integral cross sections (ICSs) and the momentum-transfer cross sections (MTCSs) for Adenine, Guanine, Thymine and Cytosine. The calculations show very clearly the important role of the dominant long-range interaction between the positron projectile and the permanent dipole-moments of the target molecules in deciding the relative sizes of the ICSs and MTCSs for the present series of molecules. Such results confirm the largely repulsive interaction between positron and DNA bases, which is nevertheless producing very large cross sections and marked deflection functions from the latter molecules. Contribution to the Topical Issue "Nano-scale Insights into Ion-beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Paulo Limão-Vieira and Malgorzata Smialek-Telega.

  17. The effect of breakup of 6Li on elastic scattering and fusion with 28Si at near barrier energies

    NASA Astrophysics Data System (ADS)

    Sinha, Mandira; Roy, Subinit; Basu, P.; Majumdar, H.

    2016-01-01

    Elastic scattering angular distributions for 6Li+28Si system were measured at Elab = 16, 21MeV and analyzed along with the existing data from the previous measurements in the energy range of Elab = 7.5 - 27MeV. The measured cross-sections and the existing data, forming a set of angular distributions over a range of E/Vb = 0.9 - 3.23, were analyzed using the phenomenological optical model potential (OMP). Three different sets of potential parameters were used. The energy dependence of the real and the imaginary potential strengths were, subsequently, extracted at the radius of sensitivity (Rav) for the system. Continuum Discretized Coupled Channel (CDCC) calculation was performed to explore the contribution of projectile break-up (BU) on the observed energy dependence of the effective potential for elastic scattering of 6Li from 28Si. The energy variation of the strength of the real potential with continuum coupling was found to agree with the energy dependence of the same extracted from the (OMP) analysis at energies around the barrier. But the behavior of the imaginary strength appeared to be different. The calculated fusion cross-sections, including the effect of BU, clearly overestimated the measured fusion excitation function data in the below and near barrier energies but compared well with the data at higher energies.

  18. Electron density of Rhizophora spp. wood using Compton scattering technique at 15.77, 17.48 and 22.16 keV XRF energies

    NASA Astrophysics Data System (ADS)

    Shakhreet, B. Z.; Bauk, S.; Shukri, A.

    2015-02-01

    Compton (incoherently) scattered photons which are directly proportional to the electron density of the scatterer, have been employed in characterizing Rhizophora spp. as breast tissue equivalent. X-ray fluorescent scattered incoherently from Rhizophora spp. sample was measured using Si-PIN detector and three XRF energy values 15.77, 17.48 and 22.16 keV. This study is aimed at providing electron density information in support of the introduction of new tissue substitute materials for mammography phantoms.

  19. Possibilities of studying the structure of halo nuclei in reactions of quasifree proton scattering at low energies

    SciTech Connect

    Zuyev, S. V. Kasparov, A. A.; Konobeevski, E. S.

    2015-07-15

    The possibility of experimentally studying the structure of halo nuclei in reactions induced by quasifree proton scattering on clusters of these nuclei is considered. Quasifree proton scattering on {sup 6}He, {sup 4}He, {sup 4}n, {sup 2}n, and n clusters in inverse kinematics is considered for the example of the {sup 8}He nucleus. Angular and energy distributions of secondaries are obtained for various representations of the cluster structure of the {sup 8}He nucleus. It is clearly shown that, in the angular and energy distributions of secondaries, one can single out regions that receive dominant contributions from reactions on specific clusters and which correspond to concrete cluster configurations of halo nuclei. Possible relevant experiments are proposed.

  20. Scattering-layer-induced energy storage function in polymer-based quasi-solid-state dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Jiang, Hongrui

    2015-03-01

    Photo-self-charging cells (PSCs) are compact devices with dual functions of photoelectric conversion and energy storage. By introducing a scattering layer in polymer-based quasi-solid-state dye-sensitized solar cells, two-electrode PSCs with highly compact structure were obtained. The charge storage function stems from the formed ion channel network in the scattering layer/polymer electrolyte system. Both the photoelectric conversion and the energy storage functions are integrated in only the photoelectrode of such PSCs. This design of PSC could continuously output power as a solar cell with considerable efficiency after being photo-charged. Such PSCs could be applied in highly-compact mini power devices.

  1. Scattering-layer-induced energy storage function in polymer-based quasi-solid-state dye-sensitized solar cells

    PubMed Central

    Zhang, Xi; Jiang, Hongrui

    2015-01-01

    Photo-self-charging cells (PSCs) are compact devices with dual functions of photoelectric conversion and energy storage. By introducing a scattering layer in polymer-based quasi-solid-state dye-sensitized solar cells, two-electrode PSCs with highly compact structure were obtained. The charge storage function stems from the formed ion channel network in the scattering layer/polymer electrolyte system. Both the photoelectric conversion and the energy storage functions are integrated in only the photoelectrode of such PSCs. This design of PSC could continuously output power as a solar cell with considerable efficiency after being photo-charged. Such PSCs could be applied in highly-compact mini power devices. PMID:25829547

  2. Phonon self-energy and origin of anomalous neutron scattering spectra in SnTe and PbTe thermoelectrics

    SciTech Connect

    Li, Chen; Ma, Jie; May, Andrew F; Cao, Huibo; Christianson, Andrew D; Ehlers, Georg; Singh, David J; Sales, Brian C; Delaire, Olivier A

    2014-01-01

    The anharmonic lattice dynamics of rock-salt thermoelectric compounds SnTe and PbTe are investigated with inelastic neutron scattering (INS) and first-principles calculations. The experiments show that, surprisingly, although SnTe is closer to the ferroelectric instability, phonon spectra in PbTe exhibit a more anharmonic character. This behavior is reproduced in first-principles calculations of the temperature-dependent phonon self-energy. Our simulations reveal how the nesting of phonon dispersions induces prominent features in the self-energy, which account for the measured INS spectra and their temperature dependence. We establish that the phase-space for three-phonon scattering processes, rather than just the proximity to the lattice instability, is the mechanism determining the complex spectrum of the transverse-optical ferroelectric mode.

  3. Global analysis of the source and detector nonstandard interactions using the short baseline ν -e and ν ¯ -e scattering data

    NASA Astrophysics Data System (ADS)

    Khan, Amir N.

    2016-05-01

    We present a global analysis of the semileptonic and purely leptonic nonuniversal and flavor-changing nonstandard neutrino interactions in all the known short-baseline neutrino—and antineutrino—electron scattering experiments. The nonstandard effects at the source and at the detector can be more transparent in these experiments because of the negligibly small ratio between the baselines and neutrino energies, which is not enough for the neutrinos to oscillate, and thus can be sensitive to the new physics at both ends. We use data from two electron-neutrino electron scattering experiments and six electron-antineutrino electron scattering experiments, combine them to find the best fits on the nonstandard parameters using the source-only, detector-only analyses, and then find the interplay between the two cases. The bounds obtained in some cases are stronger and new, in some cases comparable to the current ones, and in other cases weaker. For instance, the bound obtained from the interplay between the source and detector nonstandard physics on the nonstandard parameter ɛee u d L at the source is much stronger and is comparable with the indirect bound, but the bounds on the parameters ɛμe u d L and ɛτe u d L are weaker in this study in comparison with the indirect bounds. We also find a global fit on the standard weak mixing angle sin2θW=0.249 ±0.020 with 2% improvement in its precision in comparison with the previous studies.

  4. Compton scattering from C12 using tagged photons in the energy range 65-115 MeV

    NASA Astrophysics Data System (ADS)

    Myers, L. S.; Shoniyozov, K.; Preston, M. F.; Anderson, M. D.; Annand, J. R. M.; Boselli, M.; Briscoe, W. J.; Brudvik, J.; Capone, J. I.; Feldman, G.; Fissum, K. G.; Hansen, K.; Henshaw, S. S.; Isaksson, L.; Jebali, R.; Kovash, M. A.; Lewis, K.; Lundin, M.; MacGregor, I. J. D.; Middleton, D. G.; Mittelberger, D. E.; Murray, M.; Nathan, A. M.; Nutbeam, S.; O'Rielly, G. V.; Schröder, B.; Seitz, B.; Stave, S. C.; Weller, H. R.; Compton@Max-Lab Collaboration

    2014-03-01

    Elastic scattering of photons from C12 has been investigated using quasimonoenergetic tagged photons with energies in the range 65-115 MeV at laboratory angles of 60∘, 120∘, and 150∘ at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the 12C(γ ,γ)12C cross section to the bound-nucleon polarizabilities.

  5. Measurement of energy spectra of small-angle scattering and distribution of optical microinhomogeneities in laser ceramics

    SciTech Connect

    Tverdokhleb, P E; Shepetkin, Yu A; Steinberg, I Sh; Belikov, A Yu; Vatnik, S M; Vedin, I A; Kurbatov, P F

    2014-06-30

    The energy spectra of small-angle light scattering from the samples of Nd:YAG ceramics and the spatial distributions of optical microinhomogeneities in them are measured. The spatial profiles of microinhomogeneities are found using the collinear heterodyne microprobe technique. Based on the obtained data, the comparison of noise and lasing characteristics of foreign and domestic samples of laser ceramics is carried out. (extreme light fields and their applications)

  6. Distribution of Linearly Polarized Gluons and Elliptic Azimuthal Anisotropy in Deep Inelastic Scattering Dijet Production at High Energy

    NASA Astrophysics Data System (ADS)

    Dumitru, Adrian; Lappi, Tuomas; Skokov, Vladimir

    2015-12-01

    We determine the distribution of linearly polarized gluons of a dense target at small x by solving the Balitsky-Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner rapidity evolution equations. From these solutions, we estimate the amplitude of ˜cos 2 ϕ azimuthal asymmetries in deep inelastic scattering dijet production at high energies. We find sizable long-range in rapidity azimuthal asymmetries with a magnitude in the range of v2=⟨cos 2 ϕ ⟩˜10 % .

  7. Optimization of energy window and evaluation of scatter compensation methods in MPS using the ideal observer with model mismatch

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Links, Jonathan M.; Frey, Eric

    2015-03-01

    In this work, we used the ideal observer (IO) and IO with model mismatch (IO-MM) applied in the projection domain and an anthropomorphic Channelized Hotelling Observer (CHO) applied to reconstructed images to optimize the acquisition energy window width and evaluate various scatter compensation methods in the context of a myocardial perfusion SPECT defect detection task. The IO has perfect knowledge of the image formation process and thus reflects performance with perfect compensation for image-degrading factors. Thus, using the IO to optimize imaging systems could lead to suboptimal parameters compared to those optimized for humans interpreting SPECT images reconstructed with imperfect or no compensation. The IO-MM allows incorporating imperfect system models into the IO optimization process. We found that with near-perfect scatter compensation, the optimal energy window for the IO and CHO were similar; in its absence the IO-MM gave a better prediction of the optimal energy window for the CHO using different scatter compensation methods. These data suggest that the IO-MM may be useful for projection-domain optimization when model mismatch is significant, and that the IO is useful when followed by reconstruction with good models of the image formation process.

  8. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    Li, Z. P.; Hillhouse, G. C.; Meng, J.

    2008-07-15

    We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.

  9. Low energy excitations in iridates studied with Resonant Inelastic X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Liu, Xuerong

    2013-03-01

    In the iridium oxides, the strong spin-orbit coupling (SOC) of the 5d iridium electrons entangles the orbital and spin degrees of freedom, providing opportunities for exotic magnetic states with highly anisotropic exchange interactions. At the same time, the spatially extended 5d electrons are expected to have much stronger hybridization with the oxygen 2p orbitals, comparing with that in 3d transition element compounds. Both factors make crystal symmetry and local environment crucial in determining the electronic and magnetic properties of the iridates. We present here our resonant inelastic X-ray scattering (RIXS) studies of a number of octahedrally coordinated iridates with special structures, exploring these effects. In particular, for the 1-D spin 1/2 chain compound, Sr3CuIrO6, the wavefunction of the hole in the t2g manifold was reconstructed based on the RIXS spectra. Our results show that it is significantly modified from the isotropic shape expected for Jeff = 1 / 2 states in the strong SOC limit, due to the distortion of the oxygen octahedral cage. This distortion is comparable to, or smaller than, that present in most iridates and thus this work emphasizes the importance of local symmetry for the iridate families. Further, the magnetic excitations of this material were also measured. A large gap of ~30 meV, was found, comparable to the magnetic dispersion bandwidth. This is in contrast to the gapless dispersion expected for linear chain with isotropic Heisenberg exchange interaction. We also studied Na4Ir3O8 which has a hyperkagome lattice, and is a candidate quantum spin liquid. Here, a low energy continuum is observed below the d-d excitations. Optical conductivity measurements performed on the same sample and polarization dependence of the RIXS signal suggest that these excitations are magnetic in origin, agreeing with the spin-liquid state prediction. The work at Brookhaven was supported by the U.S. Department of Energy, Division of Materials Science

  10. High-energy gamma-ray beams from nonlinear Thomson and Compton scattering in the ultra-intense regime

    NASA Astrophysics Data System (ADS)

    Harvey, Christopher; Marklund, Mattias; Wallin, Erik

    2015-05-01

    We consider the Thomson and Compton scattering of high-energy electrons in an intense laser pulse. Our simulations show that energy losses due to radiation reaction cause the emitted radiation to be spread over a broader angular range than the case without these losses included. We explain this in terms of the effect of these energy losses on the particle dynamics. Finally, at ultra-high intensities, i.e. fields with a dimensionless parameter a0~200, the energy of the emission spectrum is significantly reduced by radiation reaction and also the classical and QED results begin to differ. This is found to be due to the classical theory overestimating the energy loss of the electrons. Such findings are relevant to radiation source development involving the next generation of high-intensity laser facilities.

  11. Detailed study and mean field interpretation of {sup 16}O+{sup 12}C elastic scattering at seven medium energies

    SciTech Connect

    Nicoli, M. P.; Haas, F.; Freeman, R. M.; Szilner, S.; Basrak, Z.; Morsad, A.; Satchler, G. R.; Brandan, M. E.

    2000-03-01

    Detailed measurements of the elastic scattering of {sup 16}O ions from {sup 12}C have been carried out at seven energies from 62 to 124 MeV, at center-of-mass angles from about 10 degree sign to about 145 degree sign . A coherent optical model analysis of these data has been performed using both the Woods-Saxon and the folding-model potentials. The extracted results are consistent with analyses of data at higher energies for this and similar light heavy-ion systems. Some model-independent spline forms for the real potentials were also investigated. (c) 2000 The American Physical Society.

  12. The spectral energy distribution of the scattered light from dark clouds

    NASA Technical Reports Server (NTRS)

    Mattila, Kalevi; Schnur, G. F. O.

    1989-01-01

    A dark cloud is exposed to the ambient radiation field of integrated starlight in the Galaxy. Scattering of starlight by the dust particles gives rise to a diffuse surface brightness of the dark nebula. The intensity and the spectrum of this diffuse radiation can be used to investigate, e.g., the scattering parameters of the dust, the optical thickness of the cloud, and as a probe of the ambient radiation field at the location of the cloud. An understanding of the scattering process is also a prerequisite for the isolation of broad spectral features due to fluorescence or to any other non-scattering origin of the diffuse light. Model calculations are presented for multiple scattering in a spherical cloud. These calculations show that the different spectral shapes of the observed diffuse light can be reproduced with standard dust parameters. The possibility to use the observed spectrum as a diagnostic tool for analyzing the thickness of the cloud and the dust particle is discussed.

  13. Theoretical Studies of Energy and Momentum Exchange in Atomic and Molecular Scattering from Surfaces

    SciTech Connect

    Joseph R. Manson

    2005-06-30

    The contributions that we have made during the grant period of DE-FG02-98ER45704 can be placed into six different categories: (1) advances in the Theory of Molecule-Surface Scattering, (2) advances in the Theory of Atom-Surface Scattering, (3) utilization of scattering theory to Extract Physical Information about Surfaces, (4) Gas-Surface Interactions, (5) Ion Scattering from surfaces and (6) Scanning Tunneling Microscopy (STM). These six topics are discussed below as individual listings under the title 'IV. Detailed description of research accomplishments'. These advances show that we have made significant progress on several scientific problems in atomic and molecular surface scattering during the course of this grant as well as contributions to other areas. It is also noted that this work, although fundamentally theoretical, is marked by its strong motivation to explain current experimental measurements. This was an important secondary goal in the proposed work. We have developed theory that is useful to experimentalists in the explanation and analysis of their experimental data.

  14. High energy Coulomb-scattered electrons for relativistic particle beam diagnostics

    NASA Astrophysics Data System (ADS)

    Thieberger, P.; Altinbas, Z.; Carlson, C.; Chasman, C.; Costanzo, M.; Degen, C.; Drees, K. A.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Marusic, A.; Miller, T.; Minty, M.; Montag, C.; Luo, Y.; Pikin, A. I.; White, S. M.

    2016-04-01

    A new system used for monitoring energetic Coulomb-scattered electrons as the main diagnostic for accurately aligning the electron and ion beams in the new Relativistic Heavy Ion Collider (RHIC) electron lenses is described in detail. The theory of electron scattering from relativistic ions is developed and applied to the design and implementation of the system used to achieve and maintain the alignment. Commissioning with gold and 3He beams is then described as well as the successful utilization of the new system during the 2015 RHIC polarized proton run. Systematic errors of the new method are then estimated. Finally, some possible future applications of Coulomb-scattered electrons for beam diagnostics are briefly discussed.

  15. Elastic and inelastic scattering of 16O and 18O ions from 64Zn at energies near the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Salém-Vasconcelos, S.; Takagui, E. M.; Bechara, M. J.; Koide, K.; Dietzsch, O.; Bairrio Nuevo, A., Jr.; Takai, H.

    1994-08-01

    Coulomb-nuclear interference effects were investigated in the inelastic scattering of 16O and 18O by 64Zn. Measurements of elastic and inelastic angular distributions of 18O were performed at a laboratory energy of 49 MeV, over the angular range from θlab~30° to 85°. The excitation functions of 16O and 18O ions were measured at incident energies between 29 and 46 MeV at θlab=174°. The experimental angular distributions show structures which are more pronounced for projectile excitation than for target excitation. The interference minimum for the excitation of the 18O first 2+ state was found to be shifted towards forward angles by approximately 5° (c.m.) with respect to the distorted-wave Born approximation calculations and by approximately 3.5° (c.m.) with respect to the coupled-channels calculations. A pronounced Coulomb-nuclear interference minimum was seen in the excitation of 64Zn(2+) state by inelastic scattering of 16O projectiles, whereas no pronounced minimum was observed in target excitation by 18O projectiles. The elastic scattering data were analyzed with the optical model. The inelastic differential cross sections for the excitation of the first 2+ states in the target and in the 18O projectile were analyzed using the distorted-wave Born approximation and also the coupled-channels approach with collective form factors.

  16. Initial evaluation of a modified dual-energy window scatter correction method for CZT-based gamma cameras for breast SPECT

    NASA Astrophysics Data System (ADS)

    Mann, Steve D.; Tornai, Martin P.

    2015-03-01

    Solid state Cadmium Zinc Telluride (CZT) gamma cameras for SPECT imaging offer significantly improved energy resolution compared to traditional scintillation detectors. However, the photopeak resolution is often asymmetric due to incomplete charge collection within the detector, resulting in many photopeak events incorrectly sorted into lower energy bins ("tailing"). These misplaced events contaminate the true scatter signal, which may negatively impact scatter correction methods that rely on estimates of scatter from the spectra. Additionally, because CZT detectors are organized into arrays, each individual detector element may exhibit different degrees of tailing. Here, we present a modified dualenergy window scatter correction method for emission detection and imaging that attempts to account for positiondependent effects of incomplete charge collection in the CZT gamma camera of our dedicated breast SPECT-CT system. Point source measurements and geometric phantoms were used to estimate the impact of tailing on the scatter signal and extract a better estimate of the ratio of scatter within two energy windows. To evaluate the method, cylindrical phantoms with and without a separate fillable chamber were scanned to determine the impact on quantification in hot, cold, and uniform background regions. Projections were reconstructed using OSEM, and the results for the traditional and modified scatter correction methods were compared. Results show that while modest reduced quantification accuracy was observed in hot and cold regions of the multi-chamber phantoms, the modified scatter correction method yields up to 8% improved quantification accuracy with 4% less added noise than the traditional DEW method within uniform background regions.

  17. High energy resolution inelastic x-ray scattering at the SRI-CAT

    SciTech Connect

    Macrander, A.T.

    1996-08-01

    This report is a combination of vugraphs and two papers. The vugraphs give information on the beamline at the APS for IXS and the science addressable by IXS. They also cover the 10 milli-eV resolution spectrometer and the 200 milli-eV resolution spectrometer. The first paper covers the performance of the focusing Ge(444) backscattering analyzers for the inelastic x-ray scattering. The second paper discusses inelastic x-ray scattering from TiC and Ti single crystals.

  18. Coulomb suppression in the low-energy p-p elastic scattering via the Trojan Horse Method

    SciTech Connect

    Tumino, A.; Spitaleri, C.; Rapisarda, G. G.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A.; Campajola, L.; Elekes, Z.; Fueloep, Zs.; Gyuerky, G.; Kiss, G. G.; Somorjai, E.; Gialanella, L.

    2010-11-24

    We present here an important test of the main feature of the Trojan Horse Method (THM), namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. This is done by measuring the THM p-p elastic scattering via the p+d{yields}p+p+n reaction at 4.7 and 5 MeV, corresponding to a p-p relative energy ranging from 80 to 670 keV. In contrast to the on-energy-shell (OES) case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum due to the suppression of the Coulomb amplitude. This is confirmed by the half-off-energy shell (HOES) calculations and strengthened by the agreement with the calculated OES nuclear cross sections.

  19. Neutron inelastic scattering measurements of low-energy phonons in the multiferroic BiFeO3

    SciTech Connect

    Schneeloch, John A.; Xu, Zhijun; Wen, Jinsheng; Gehring, P. M.; Stock, C.; Matsuda, Masaaki; Winn, Barry L.; Gu, Genda; Shapiro, Stephen M.; Birgeneau, R. J.; Ushiyama, T.; Yanagisawa, Y.; Tomioka, Y.; Ito, T.; Xu, Guangyong

    2015-02-10

    In this study, we present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010], and TA2 along [110]) and two low-energy optic phonon modes (LO and TO1) have been mapped out between 300 and 700 K. Elastic constants are extracted from the phonon measurements. The energy linewidths of both TA phonons at the zone boundary clearly broaden when the system is warmed toward the magnetic ordering temperature TN=640 K. In conclusion, this suggests that the magnetic order and low-energy lattice dynamics in this multiferroic material are coupled.

  20. Neutron inelastic scattering measurements of low-energy phonons in the multiferroic BiFeO3

    DOE PAGESBeta

    Schneeloch, John A.; Xu, Zhijun; Wen, Jinsheng; Gehring, P. M.; Stock, C.; Matsuda, Masaaki; Winn, Barry L.; Gu, Genda; Shapiro, Stephen M.; Birgeneau, R. J.; et al

    2015-02-10

    In this study, we present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010], and TA2 along [110]) and two low-energy optic phonon modes (LO and TO1) have been mapped out between 300 and 700 K. Elastic constants are extracted from the phonon measurements. The energy linewidths of both TA phonons at the zone boundary clearly broaden when the system is warmed toward the magnetic ordering temperature TN=640 K. In conclusion, this suggests that the magnetic order and low-energy lattice dynamics in thismore » multiferroic material are coupled.« less

  1. Effective atomic numbers of blue topaz at different gamma-rays energies obtained from Compton scattering technique

    SciTech Connect

    Tuschareon, S. Limkitjaroenporn, P. Kaewkhao, J.

    2014-03-24

    Topaz occurs in a wide range of colors, including yellow, orange, brown, pink-to-violet and blue. All of these color differences are due to color centers. In order to improve the color of natural colorless topaz, the most commonly used is irradiated with x- or gamma-rays, indicated that attenuation parameters is important to enhancements by irradiation. In this work, the mass attenuation coefficients of blue topaz were measured at the different energy of γ-rays using the Compton scattering technique. The results show that, the experimental values of mass attenuation coefficient are in good agreement with the theoretical values. The mass attenuation coefficients increase with the decrease in gamma rays energies. This may be attributed to the higher photon interaction probability of blue topaz at lower energy. This result is a first report of mass attenuation coefficient of blue topaz at different gamma rays energies.

  2. Effective atomic numbers of blue topaz at different gamma-rays energies obtained from Compton scattering technique

    NASA Astrophysics Data System (ADS)

    Tuschareon, S.; Limkitjaroenporn, P.; Kaewkhao, J.

    2014-03-01

    Topaz occurs in a wide range of colors, including yellow, orange, brown, pink-to-violet and blue. All of these color differences are due to color centers. In order to improve the color of natural colorless topaz, the most commonly used is irradiated with x- or gamma-rays, indicated that attenuation parameters is important to enhancements by irradiation. In this work, the mass attenuation coefficients of blue topaz were measured at the different energy of γ-rays using the Compton scattering technique. The results show that, the experimental values of mass attenuation coefficient are in good agreement with the theoretical values. The mass attenuation coefficients increase with the decrease in gamma rays energies. This may be attributed to the higher photon interaction probability of blue topaz at lower energy. This result is a first report of mass attenuation coefficient of blue topaz at different gamma rays energies.

  3. Near shot-noise limited hyperspectral stimulated Raman scattering spectroscopy using low energy lasers and a fast CMOS array.

    PubMed

    Rock, William; Bonn, Mischa; Parekh, Sapun H

    2013-07-01

    We demonstrate near shot-noise limited hyperspectral stimulated Raman scattering (SRS) spectroscopy using oscillator-only excitation conditions. Using a fast CMOS camera synchronized to an acousto-optic modulator and subtracting subsequent frames acquired at up to 1 MHz frame rates, we demonstrate demodulation and recovery of the SRS spectrum. Surprisingly, we observe that the signal-to-noise of SRS spectra is invariant at modulation frequencies down to 2.5 kHz. Our approach allows for a direct comparison of SRS with coherent anti-Stokes Raman scattering (CARS) spectroscopy under identical experimental conditions. Our findings suggest that hyperspectral SRS imaging with shot-noise limited performance at biologically compatible excitation energies is feasible after minor modifications to fast frame-rate CMOS array technology. PMID:23842298

  4. Absolute elastic differential electron scattering cross sections in the intermediate energy region. III - SF6 and UF6

    NASA Technical Reports Server (NTRS)

    Srivastava, S. K.; Trajmar, S.; Chutjian, A.; Williams, W.

    1976-01-01

    A recently developed technique has been used to measure the ratios of elastic differential electron scattering cross sections (DCS) for SF6 and UF6 to those of He at electron impact energies of 5, 10, 15, 20, 30, 40, 50, 60, and 75 eV and at scattering angles of 20 to 135 deg. In order to obtain the absolute values of DCS from these ratios, He DCS of McConkey and Preston have been employed in the 20 to 90 deg range. At angles in the 90 to 135 deg range the recently determined cross sections of Srivastava and Trajmar have been utilized. From these DCS, elastic integral and momentum transfer cross sections have been obtained.

  5. Low-Energy Parameters of the Nucleon-Nucleon Scattering and Deuteron Properties, Electromagnetic Interactions with Bound Systems

    NASA Astrophysics Data System (ADS)

    Shebeko, A.; Dubovik, E.

    2013-08-01

    One more application of the method of unitary clothing transformations (UCT's) in the theory of nucleon-nucleon ( N - N) interaction has been presented. We have extended our previous analysis (Dubovik and Shebeko in Few-Body Syst 48:109-142, 2010) of the N - N scattering below the pion production threshold to treat the neutron-proton ( n - p) scattering at low energies and the deuteron static properties. Our calculations of deuteron magnetic and quadrupole moments have been carried out in the framework of a gauge independent description of electromagnetic (EM) interactions with nuclei (bound systems) using the clothed particle representation of the Hamiltonian, the boost and EM current density operators for the n-p system.

  6. Mapping the energy density of shaped waves in scattering media onto a complete set of diffusion modes.

    PubMed

    Ojambati, Oluwafemi S; Mosk, Allard P; Vellekoop, Ivo M; Lagendijk, Ad; Vos, Willem L

    2016-08-01

    We study the energy density of shaped waves inside a quasi-1D disordered waveguide. We find that the spatial energy density of optimally shaped waves, when expanded in the complete set of eigenfunctions of the diffusion equation, is well described by considering only a few of the lowest eigenfunctions. Taking into account only the fundamental eigenfunction, the total internal energy inside the sample is underestimated by only 2%. The spatial distribution of the shaped energy density is very similar to the fundamental eigenfunction, up to a cosine distance of about 0.01. We obtain the energy density of transmission eigenchannels inside the sample by numerical simulation of the scattering matrix. Computing the transmission-averaged energy density over all transmission channels yields the ensemble averaged energy density of shaped waves. From the averaged energy density, we reconstruct its spatial distribution using the eigenfunctions of the diffusion equation. The results of our study have exciting applications in controlled biomedical imaging, efficient light harvesting in solar cells, enhanced energy conversion in solid-state lighting, and low threshold random lasers. PMID:27505816

  7. Very low-energy total cross sections and the experimental scattering length for the positron-xenon system

    NASA Astrophysics Data System (ADS)

    Zecca, Antonio; Chiari, Luca; Trainotti, Emanuele; Brunger, Michael J.

    2012-04-01

    We report total cross-section (TCS) results for low-energy positron scattering from the noble gas xenon. A comparison with previous measurements shows a good level of accord with the recent results of the ANU group (2011 New J. Phys. 13 125004). Very good qualitative agreement is also found with the convergent close-coupling (CCC) calculation of Fursa and Bray (2012 New J. Phys. 14 035002) over most of the common energies. By using the shape of the CCC results as a guide, we also extrapolate our measured cross sections to very low energy. With the aid of the CCC theory, we therefore derive the first experimental estimate for the positron-xenon scattering length of a = -99.2 ± 18.4 au. This value is found to be consistent with the CCC-based estimate and also with those of some other theories. This result supports the existence of a positron-xenon virtual state at a positron energy ɛ = (1.4 ± 0.6) × 10-3 eV.

  8. Single-collision approximation for p{sup 3}-He elastic scattering at low energy

    SciTech Connect

    Abusini, M.

    2009-06-15

    A theoretical approach to studying four-body reactions of p{sup 3}-He elastic scattering that takes consistently into account the single-collision mechanism is reported. The theoretical results obtained by this method were compared with experimental data, and the agreement is found to be quite satisfactory.

  9. Elastic pp Scattering at LHC Energies in Various Multi-Pomeron Exchange Models

    NASA Astrophysics Data System (ADS)

    Novikov, Ivan; Shabelski, Yuli

    2012-10-01

    We consider the data for elastic pp scattering in the framework of Regge theory in various models of multiple Pomeron exchanges: quasi-eikonal approach and two-channel approach. The results of the model calculations are compared with the experimental data presented by the TOTEM collaboration.

  10. Evaluation of Compton attenuation and photoelectric absorption coefficients by convolution of scattering and primary functions and counts ratio on energy spectra

    PubMed Central

    Ashoor, Mansour; Asgari, Afrouz; Khorshidi, Abdollah; Rezaei, Ali

    2015-01-01

    Purpose: Estimation of Compton attenuation and the photoelectric absorption coefficients were explored at various depths. Methods: A new method was proposed for estimating the depth based on the convolution of two exponential functions, namely convolution of scattering and primary functions (CSPF), which the convolved result will conform to the photopeak region of energy spectrum with the variable energy-window widths (EWWs) and a theory on the scattering cross-section. The triple energy-windows (TEW) and extended triple energy-windows scatter correction (ETEW) methods were used to estimate the scattered and primary photons according to the energy spectra at various depths due to a better performance than the other methods in nuclear medicine. For this purpose, the energy spectra were employed, and a distinct phantom along with a technetium-99 m source was simulated by Monte Carlo method. Results: The simulated results indicate that the EWW, used to calculate the scattered and primary counts in terms of the integral operators on the functions, was proportional to the depth as an exponential function. The depth will be calculated by the combination of either TEW or ETEW and proposed method resulting in the distinct energy-window. The EWWs for primary photons were in good agreement with those of scattered photons at the same as depths. The average errors between these windows for both methods TEW, and ETEW were 7.25% and 6.03% at different depths, respectively. The EWW value for functions of scattered and primary photons was reduced by increasing the depth in the CSPF method. Conclusions: This coefficient may be an index for the scattering cross-section. PMID:26170567

  11. [Determination of Trace Boron Based on Gold Nanorod Plasmonic Resonance Rayleigh Scattering Energy Transfer to the Coordinate].

    PubMed

    Ye, Ling-ling; Li, Ting-sheng; Luo, Yang-he; Wen, Gui-qing; Liang, Ai-hui; Jiang, Zhi-liang

    2015-05-01

    B is a necessary trace element for human and animals, but the excess intake of B caused poison. Thus, it is very important to determination of B in foods and water. The target of this study is development of a new, sensitive and selective resonance Rayleigh scattering energy transfer (RRS-ET) for the determination of B. The combination of energy transfer with resonance Rayleigh scattering (RRS) has developed a new technology called RRS-ET, which can realize selective and sensitive detection of boric acid. The gold nanorods in diameter of 12 nm and length of 37 nm were prepared by the seed growth procedure. In pH 5. 6 NH4 Ac-HAc buffer solution and in the presence of azomethine-H (AMH), the gold nanorod particles exhibited a strong resonance Rayleigh scattering (RRS) peak at 404 nm. In the presence of boric acid, it reacts with AMH to form AMH-boric acid (AMH-B) complexes. When the complexe as a receptor close to the gold nanorod as a donor, the resonance Rayleigh scattering energy transfer (RRS-ET) take placed that resulted in the Rayleigh scattering signal quenching. With the increase of the concentration of boric acid, the formed complexes increased, the scattering light energy of gold nanorod transfer to the complexes increased, resulting in the Rayleigh scattering intensity linearly reduced at 404 nrn. The decreased RRS intensity responds linearly to the concentration of boron over 10~750 ng . mL-1 B, with a regress equation of ΔI404 nm =3. 53c+24 and a detection of 5 ng mL-1 B. The influence of coexistence substances on the RRS-ET determination of 2. 3 X 10(-7) mol . L-1 B was considered in details. Results showed that this new RRS-ET method is of high selectivity, that is, 4 X 10(-4) mol . L-1 Mn2+, Cd2+, Zn2+, Bi+, Na+, Al3+, glucose, Hg2+, IO3-, F-, SO(2-)3, SiO3-, NO3-, CIO4-, H2O2, mannitol, glycerol, and ethylene glycol, 4X 10(-5) mol . L-1 L-tyrosine, and 2 X 10(-4) mol . L-1 L-glutamic acid do not interfere with the determination. Based on this, a new

  12. Energy loss and electron emission during grazing scattering of fast noble gas atoms from an Al(1 1 1) surface

    NASA Astrophysics Data System (ADS)

    Lederer, S.; Winter, H.; Winter, HP.

    2007-05-01

    Electron loss and electron emission for grazing impact of noble gas atoms with energies in the keV domain are investigated via time-of-flight spectra recorded in coincidence with the number of emitted electrons. The data is analyzed in terms of computer simulations concerning the interaction of the fast atoms with the electron gas in the selvedge of the Al(1 1 1) surface. The interaction is approximated by binary collisions of the fast atoms with Fermi electrons of the conduction band and differential cross sections obtained for electron scattering from free atoms. For an effective number of collisions of about 50 the energy loss spectra are fairly well reproduced by our calculations. We show that for our conditions the shift of the energy spectra for the emission of an additional electron from the surface is close to the work function of the target.

  13. Multiple-scattering distributions and angular dependence of the energy loss of slow protons in copper and silver

    NASA Astrophysics Data System (ADS)

    Cantero, E. D.; Lantschner, G. H.; Eckardt, J. C.; Lovey, F. C.; Arista, N. R.

    2010-04-01

    Measurements of angular distributions and of the angular dependence of the energy loss of 4-, 6-, and 9-keV protons transmitted through thin Cu and Ag polycrystalline foils are presented. By means of standard multiple-scattering model calculations it is found that a V(r)∝r-2.8 potential leads to significantly better fits of the angular distributions than the standard Thomas Fermi, Lenz-Jensen, or Ziegler-Biersack-Littmark potentials. A theoretical model for the angular dependence of the energy loss based on considering geometric effects on a frictional inelastic energy loss plus an angular-dependent elastic contribution and the effects of foil roughness reproduces the experimental data. This agrees with previous results in Au and Al, therefore extending the applicability of the model to other metallic elements.

  14. Multiple-scattering distributions and angular dependence of the energy loss of slow protons in copper and silver

    SciTech Connect

    Cantero, E. D.; Lantschner, G. H.; Eckardt, J. C.; Lovey, F. C.; Arista, N. R.

    2010-04-15

    Measurements of angular distributions and of the angular dependence of the energy loss of 4-, 6-, and 9-keV protons transmitted through thin Cu and Ag polycrystalline foils are presented. By means of standard multiple-scattering model calculations it is found that a V(r){proportional_to}r{sup -2.8} potential leads to significantly better fits of the angular distributions than the standard Thomas Fermi, Lenz-Jensen, or Ziegler-Biersack-Littmark potentials. A theoretical model for the angular dependence of the energy loss based on considering geometric effects on a frictional inelastic energy loss plus an angular-dependent elastic contribution and the effects of foil roughness reproduces the experimental data. This agrees with previous results in Au and Al, therefore extending the applicability of the model to other metallic elements.

  15. 3d-shell contribution to the energy loss of protons during grazing scattering from Cu(111) surfaces

    SciTech Connect

    Gravielle, M. S.; Alducin, M.; Juaristi, J. I.; Silkin, V. M.

    2007-10-15

    Motivated by a recent experimental work [S. Lederer and H. Winter, Phys. Rev. A 73, 054901 (2006)] we study the contribution of the 3d shell electrons to the energy loss of 100 keV protons scattered off from the Cu(111) surface. To describe this process we use a multiple collision formalism, where the interaction of the projectile with 3d electrons is described by means of a sequence of single encounters with atoms belonging to the first atomic layer. In order to compare the theoretical energy loss with the experimental data, we add the contribution of valence electrons, which is evaluated in linear response theory using a response function that incorporates information on the surface band structure. For completeness, the energy lost by protons is also calculated within a jellium model that includes 3d and valence electrons with equal footing. Fair agreement between theory and experiment exists when the 3d shell is taken into account in the calculation.

  16. Unusual impact of electron-phonon scattering in Si nanowire field-effect-transistors: A possible route for energy harvesting

    NASA Astrophysics Data System (ADS)

    Nag Chowdhury, Basudev; Chattopadhyay, Sanatan

    2016-09-01

    In the current work, the impact of electron-phonon scattering phenomena on the transport behaviour of silicon nanowire field-effect-transistors with sub-mean free path channel length has been investigated by developing a theoretical model that incorporates the responses of carrier effective mass mismatch between the channel and source/drain. For this purpose, a set of relevant quantum field equations has been solved by non-equilibrium Green's function formalism. The obtained device current for a particular set of biases is found to decrease due to phonon scattering below a certain doping level of source/drain, above which it is observed to enhance anomalously. Analyses of the quantified scattering lifetime and power dissipation at various confinement modes of the device indicates that such unusual enhancement of current is originated from the power served by phonons instead of associated decay processes. The power generation has been observed to improve by using high-k materials as gate insulator. Such results may contribute significantly to the future nano-electronic applications for energy harvesting.

  17. Mode- and Direction-Dependent Mechanical Energy Dissipation in Single-Crystal Resonators due to Anharmonic Phonon-Phonon Scattering

    NASA Astrophysics Data System (ADS)

    Iyer, Srikanth S.; Candler, Robert N.

    2016-03-01

    In this work, we determine the intrinsic mechanical energy dissipation limit for single-crystal resonators due to anharmonic phonon-phonon scattering in the Akhiezer (Ω τ ≪1 ) regime. The energy loss is derived using perturbation theory and the linearized Boltzmann transport equation for phonons, and includes the direction- and polarization-dependent mode-Grüneisen parameters in order to capture the strain-induced anharmonicity among phonon branches. This expression reveals the fundamental differences among the internal friction limits for different types of bulk-mode elastic waves. For cubic crystals, 2D-extensional modes have increased dissipation compared to width-extensional modes because the biaxial deformation opposes the natural Poisson contraction of the solid. Additionally, we show that shear-mode vibrations, which preserve volume, have significantly reduced energy loss because dissipative phonon-phonon scattering is restricted to pure-shear phonon branches, indicating that Lamé- or wineglass-mode resonators will have the highest upper limit on mechanical efficiency. Finally, we employ key simplifications to evaluate the quality factor limits for common mode shapes in single-crystal silicon devices, explicitly including the correct effective elastic storage moduli for different vibration modes and crystal orientations. Our expression satisfies the pressing need for a reliable analytical model that can predict the phonon-phonon dissipation limits for modern resonant microelectromechanical systems, where precise manufacturing techniques and accurate finite-element methods can be used to select particular vibrational mode shapes and crystal orientations.

  18. Non-resonant elastic scattering of low-energy photons by atomic sodium confined in quantum plasmas

    SciTech Connect

    Ghosh, Avijit Ray, Debasis

    2015-03-15

    The non-resonant elastic scattering of low-energy photons by the bound valence electron in the ground state 3s of atomic sodium confined in quantum plasmas is investigated theoretically. The incident photon energy is assumed to be much smaller than the 3s-3p excitation energy. The alkali atom sodium is first formulated as an effective one-electron problem in which the attractive interaction between the valence electron and the atomic ion core is simulated by a spherically symmetric model potential. The Shukla-Eliasson oscillatory exponential cosine screened-Coulomb potential model is then used to mimic the effective two-body (valence-core) interaction within quantum plasmas. Non-relativistic calculations performed within the electric dipole approximation indicate that the non-resonant elastic photon scattering cross-section undergoes a dramatic growth by several orders of magnitude as the quantum wave number increases. A qualitative explanation of this phenomenon is presented. In the absence of the oscillatory cosine screening term, a similar growth is observed at larger values of the quantum wave number. Our computed relevant atomic data are in very good agreement with the experimental as well as the previous theoretical data for the zero-screening (free atom) case, and with the very limited, accurate theoretical results available for the case of exponential screened-Coulomb two-body interaction, without the cosine screening term.

  19. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Adachi, T.; Itoh, K. F. K.; Kawabata, T.; Kudoh, T.; Ohira, H. M. H.; Okamura, H.; Sagara, K.; Sasamoto, Y. S. Y.; Yoshida, Y. S. H. P.; Suda, K.; Tomiyama, Y. T. A. T. M.; Uesaka, M. U. T.; Wakasa, T.; Wakui, T.

    2005-08-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of nuclei, since target related observables are extremely sensitive to small spin-dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependence of the nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering (EBS), only a small amount of data exists for the differential cross-section and none exists for spin-dependent observables. We have developed a spin-exchange polarised 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  20. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Kobushkin, A. P.; Adachi, T.; Fujita, K.; Itoh, K.; Kawabata, T.; Kudoh, T.; Matsubara, H.; Ohira, H.; Okamura, H.; Sagara, K.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Yoshida, H. P.; Suda, K.; Tameshige, Y.; Tamii, A.; Tomiyama, M.; Uchida, M.; Uesaka, T.; Wakasa, T.; Wakui, T.

    2007-01-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of the nuclei since target related observables are extremely sensitive to spin dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependent nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering, only small amount of data points exist for the differential cross section and no data exist for spin dependent observables. We developed a spin exchange type polarized 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  1. High-energy Electron Scattering and the Charge Distributions of Selected Nuclei

    DOE R&D Accomplishments Database

    Hahn, B.; Ravenhall, D. G.; Hofstadter, R.

    1955-10-01

    Experimental results are presented of electron scattering by Ca, V, Co, In, Sb, Hf, Ta, W, Au, Bi, Th, and U, at 183 Mev and (for some of the elements) at 153 Mev. For those nuclei for which asphericity and inelastic scattering are absent or unimportant, i.e., Ca, V, Co, In, Sb, Au, and Bi, a partial wave analysis of the Dirac equation has been performed in which the nuclei are represented by static, spherically symmetric charge distributions. Smoothed uniform charge distributions have been assumed; these are characterized by a constant charge density in the central region of the nucleus, with a smoothed-our surface. Essentially two parameters can be determined, related to the radium and to the surface thickness. An examination of the Au experiments show that the functional forms of the surface are not important, and that the charge density in the central regions is probably fairly flat, although it cannot be determined very accurately.

  2. A Monte Carlo study of high-energy photon transport in matter: application for multiple scattering investigation in Compton spectroscopy

    PubMed Central

    Brancewicz, Marek; Itou, Masayoshi; Sakurai, Yoshiharu

    2016-01-01

    The first results of multiple scattering simulations of polarized high-energy X-rays for Compton experiments using a new Monte Carlo program, MUSCAT, are presented. The program is developed to follow the restrictions of real experimental geometries. The new simulation algorithm uses not only well known photon splitting and interaction forcing methods but it is also upgraded with the new propagation separation method and highly vectorized. In this paper, a detailed description of the new simulation algorithm is given. The code is verified by comparison with the previous experimental and simulation results by the ESRF group and new restricted geometry experiments carried out at SPring-8. PMID:26698070

  3. Elastic Scattering Of {sup 6,7}Li+{sup 80}Se At Near And Above Barrier Energies

    SciTech Connect

    Fimiani, L.; Marti, G. V.; Capurro, O. A.; Barbara, E. de; Testoni, J. E.; Zalazar, L.; Arazi, A.; Cardona, M. A.; Carnelli, P.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J.; Fernandez Niello, J. O.

    2010-08-04

    In this work we propose to study the elastic scattering of the weakly bound projectiles {sup 6,7}Li on an intermediate mass target {sup 80}Se. From the experimental results presented here, precise angular distributions at energies below, around and above the nominal Coulomb barriers of the systems were obtained. The final goal of our work is to determine the characteristic parameters of the optical potential and use them to address the question of whether the usual threshold anomaly or the breakup threshold anomaly are present or not in these systems.

  4. Isospin breaking corrections to low-energy π-K scattering

    NASA Astrophysics Data System (ADS)

    Nehme, A.; Talavera, P.

    2002-03-01

    We evaluate the matrix elements for the processes π0K0-->π0K0 and π-K+-->π0K0 in the presence of isospin breaking terms at leading and next-to-leading order. As a direct application the relevant combination of the S-wave scattering lengths involved in the pion-kaon atom lifetime is determined. We discuss the sensitivity of the results with respect to the input parameters.

  5. A semianalytic model to extract differential linear scattering coefficients of breast tissue from energy dispersive x-ray diffraction measurements

    SciTech Connect

    LeClair, Robert J.; Boileau, Michel M.; Wang Yinkun

    2006-04-15

    The goal of this work is to develop a technique to measure the x-ray diffraction signals of breast biopsy specimens. A biomedical x-ray diffraction technology capable of measuring such signals may prove to be of diagnostic use to the medical field. Energy dispersive x-ray diffraction measurements coupled with a semianalytical model were used to extract the differential linear scattering coefficients [{mu}{sub s}(x)] of breast tissues on absolute scales. The coefficients describe the probabilities of scatter events occurring per unit length of tissue per unit solid angle of detection. They are a function of the momentum transfer argument, x=sin({theta}/2)/{lambda}, where {theta}=scatter angle and {lambda}=incident wavelength. The technique was validated by using a 3 mm diameter 50 kV polychromatic x-ray beam incident on a 5 mm diameter 5 mm thick sample of water. Water was used because good x-ray diffraction data are available in the literature. The scatter profiles from 6 deg. to 15 deg. in increments of 1 deg. were measured with a 3 mmx3 mmx2 mm thick cadmium zinc telluride detector. A 2 mm diameter Pb aperture was placed on top of the detector. The target to detector distance was 29 cm and the duration of each measurement was 10 min. Ensemble averages of the results compare well with the gold standard data of A. H. Narten [''X-ray diffraction data on liquid water in the temperature range 4 deg. C-200 deg. C, ORNL Report No. 4578 (1970)]. An average 7.68% difference for which most of the discrepancies can be attributed to the background noise at low angles was obtained. The preliminary measurements of breast tissue are also encouraging.

  6. Diffractive hard scattering

    SciTech Connect

    Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

    1986-03-01

    I discuss events in high energy hadron collisions that contain a hard scattering, in the sense that very heavy quarks or high P/sub T/ jets are produced, yet are diffractive, in the sense that one of the incident hadrons is scattered with only a small energy loss. 8 refs.

  7. Low energy electronic excitations and fano resonance in K doped C 60 from Raman scattering excited at 1.16 eV

    NASA Astrophysics Data System (ADS)

    Danieli, R.; Denisov, V. N.; Ruani, G.; Zamboni, R.; Taliani, C.; Zakhidov, A. A.; Ugawa, A.; Imaeda, K.; Yakushi, K.; Inokuchi, H.; Kikuchi, K.; Ikemoto, I.; Suzuki, S.; Achiba, Y.

    1992-01-01

    We present a Raman scattering study of pristine and K doped C 60 at various doping levels by exciting in the near-IR at 1.16 eV. The normal metallic state of K 3C 60 is characterized by a broad scattering background and by the resonance of low energy phonons in the range of 250-500 cm -1. We assign the broad background to an electronic Raman scattering due to low energy electronic excitations. This spectral feature is indicative of an anomalous normal state behaviour and is similar to the case of high temperature ceramic superconductors. In the overdoped K 6C 60 the squashing mode at 278 cm -1 shows a Fano resonance with the electronic scattering associated with localized electronic excitations which are characteristic of isolated regions of K 3C 60 into the matrix of K 6C 60 as a result of inhomogeneous doping. The Fano resonance indicates a specific electron-phonon coupling of this Jahn-Teller mode with low energy excitations and suggests that the symmetry of this electronic excitation is h g (i.e. the same of the coupled phonon mode). We discuss the nature of the anomalous electronic Raman scattering in terms of scattering from low energy excitations involving a low lying singlet band resulting from electron correlation and/or dynamical J-T distortion caused by the squashing mode.

  8. Electron scattering from pyrimidine

    NASA Astrophysics Data System (ADS)

    Colmenares, Rafael; Fuss, Martina C.; Oller, Juan C.; Muñoz, Antonio; Blanco, Francisco; Almeida, Diogo; Limão-Vieira, Paulo; García, Gustavo

    2014-04-01

    Electron scattering from pyrimidine (C4H4N2) was investigated over a wide range of energies. Following different experimental and theoretical approaches, total, elastic and ionization cross sections as well as electron energy loss distributions were obtained.

  9. Scattering process for the system 7Be + 58Ni at 23.2 MeV beam energy

    NASA Astrophysics Data System (ADS)

    Mazzocco, M.; Torresi, D.; Fierro, N.; Acosta, L.; Boiano, A.; Boiano, C.; Glodariu, T.; Guglielmetti, A.; La Commara, M.; Martel, I.; Mazzocchi, C.; Molini, P.; Pakou, A.; Parascandolo, C.; Parker, V. V.; Patronis, N.; Pierroutsakou, D.; Romoli, M.; Sanchez-Benitez, A. M.; Sandoli, M.; Signorini, C.; Silvestri, R.; Soramel, F.; Stiliaris, E.; Strano, E.; Stroe, L.; Zerva, K.

    2013-03-01

    We measured for the first time the scattering process of 7Be nuclei from a 58Ni target at 23.2 MeV beam energy. The experiment was performed at the Laboratori Nazionali di Legnaro (LNL, Italy), where the 7Be Radioactive Ion Beam was in-flight produced with the facility EXOTIC. Charged reaction products were detected by means of the detector array DINEX, arranged in a cylindrical configuration around the target to ensure a polar angle coverage in the ranges θcm = 40°-80° and 110°-150°. The scattering differential cross section was analyzed within the optical model formalism with the coupled-channel code FRESCO to extract the total reaction cross section. The result was compared with those obtained at lower beam energies in an earlier experiment performed at the University of Notre Dame (USA). At the present stage of our analysis, the two data sets were found to be not fully consistent each other.

  10. Energy loss in medium-energy ion scattering: A combined theoretical and experimental study of the model system Y on Si(111)

    SciTech Connect

    Munoz-Marquez, M.A.; Parkinson, G.S.; Woodruff, D.P.; Hentz, A.; Grande, P.L.; Schiwietz, G.; Wood, T.J.; Bonet, C.; Tear, S.P.; Bailey, P.; Noakes, T.C.Q.

    2005-08-15

    The energy-loss spectrum associated with scattering of 100 keV H{sup +} ions from Y atoms on Si(111) has been investigated both experimentally and theoretically. Measurements were made from Y overlayers, and from the Si(111)(1x1) two-dimensional silicide phase formed by Y on this surface, in various scattering geometries and with different surface preparations. Theoretical simulations were conducted based on calculations of the energy loss experienced in specific ion trajectories through the surface, using coupled-channel calculations to describe inner-shell ionization and excitation as a function of impact parameter. The experimental results indicate that additional broadening contributions arise from surface inhomogeneity and roughness, but for near-normal incident and outgoing trajectories the theory and experiment agree quite well. The calculations show that, even for the ideal two-dimensional silicide phase in which the Y atoms lie just below the surface, significant energy loss arises from interaction of the ions with surrounding Si atoms, leading to a complete loss of intensity at zero energy loss.

  11. Electronic structure of tin oxides by electron energy loss spectroscopy and real-space multiple scattering calculations

    SciTech Connect

    Moreno, M. S.; Egerton, R.F.; Rehr, J.J.; Midgley, P.A.

    2005-01-15

    The electronic structure of the tin oxides SnO and SnO{sub 2} is studied using the fine structure of the Sn-M{sub 4,5} and oxygen K-edges measured by electron energy loss spectroscopy (EELS). The experimental results are compared with real-space multiple scattering calculations. It is observed that both edges are overlapped. The calculations reveal that the observed fine structure is due largely to the oxygen states, and that it can be used to fingerprint each phase. The calculated densities of states are similar for both compounds and suggest a covalent nature. The structures appearing within the first 10 eV above the threshold arise from a covalent mixing of mainly O 2p and Sn 5s-p. For SnO the oxygen edge is satisfactorily reproduced. Discrepancies in the predicted energy position of the features in the EELS of SnO{sub 2} are briefly discussed.

  12. Surface segregation at the binary alloy CuAu (100) studied by low-energy ion scattering

    NASA Astrophysics Data System (ADS)

    Beikler, Robert; Taglauer, Edmund

    2016-01-01

    We present results from an experimental study of segregation at the CuAu (100) surface. It is shown that Au enrichment in the top surface layer persists up to temperatures far beyond the bulk order-disorder transition temperature. From the gradual desegregation at higher temperatures a segregation energy of - 0.30 eV was determined. Our results are in quantitative agreement with calculations by Tersoff predicting oscillatory concentration depth profiles with decreasing amplitudes at higher temperatures. For the layer selective surface analysis we used low-energy He+ and Na+ scattering. Data interpretation and quantification were supported by numerical simulations with the MARLOWE code to which we had added the special features of trajectory resolved analysis and anisotropic thermal vibrations of surface atoms.

  13. Determination of SU(2) chiral perturbation theory low energy constants from a precise description of pion-pion scattering threshold parameters

    NASA Astrophysics Data System (ADS)

    Nebreda, J.; Peláez, J. R.; Ríos, G.

    2013-09-01

    We determine the values of the one- and two-loop low energy constants appearing in the SU(2) Chiral Perturbation Theory calculation of pion-pion scattering. For this we use a recent and precise sum rule determination of some scattering lengths and slopes that appear in the effective range expansion. In addition we provide sum rules for these coefficients up to third order in the expansion. Our results when using only the scattering lengths and slopes of the S, P, D, and F waves are consistent with previous determinations but seem to require higher order contributions if they are to accommodate the third order coefficients of the effective range expansion.

  14. Muon Energy Reconstruction Through the Multiple Scattering Method in the NO$\\mathrm{\

    SciTech Connect

    Psihas Olmedo, Silvia Fernanda

    2015-01-01

    Neutrino energy measurements are a crucial component in the experimental study of neutrino oscillations. These measurements are done through the reconstruction of neutrino interactions and energy measurements of their products. This thesis presents the development of a technique to reconstruct the energy of muons from neutrino interactions in the NO$\\mathrm{\

  15. Muon Energy Reconstruction Through the Multiple Scattering Method in the NO$\\mathrm{\

    SciTech Connect

    Psihas Olmedo, Silvia Fernanda

    2013-06-01

    Neutrino energy measurements are a crucial component in the experimental study of neutrino oscillations. These measurements are done through the reconstruction of neutrino interactions and energy measurements of their products. This thesis presents the development of a technique to reconstruct the energy of muons from neutrino interactions in the NO$\\mathrm{\

  16. Near-field Light Scattering Techniques for Measuring Nanoparticle-Surface Interaction Energies and Forces

    PubMed Central

    O'Dell, Dakota; Adam, Ian S.; DiPaolo, Brian; Sabharwal, Manit; Shi, Ce; Hart, Robert; Earhart, Christopher; Erickson, David

    2015-01-01

    Nanoparticles are quickly becoming commonplace in many commercial and industrial products, ranging from cosmetics to pharmaceuticals to medical diagnostics. Predicting the stability of the engineered nanoparticles within these products a priori remains an important and difficult challenge. Here we describe our techniques for measuring the mechanical interactions between nanoparticles and surfaces using near-field light scattering. Particle-surface interfacial forces are measured by optically “pushing” a particle against a reference surface and observing its motion using scattered near-field light. Unlike atomic force microscopy, this technique is not limited by thermal noise, but instead takes advantage of it. The integrated waveguide and microfluidic architecture allow for high-throughput measurements of about 1000 particles per hour. We characterize the reproducibility of and experimental uncertainty in the measurements made using the NanoTweezer surface instrument. We report surface interaction studies on gold nanoparticles with 50 nm diameters, smaller than previously reported in the literature using similar techniques. PMID:26855473

  17. Determination of the gluon distribution function of the nucleon using energy-energy angular pattern in deep-inelastic muon-deuteron scattering

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Carroll, T. J.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G. E.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H. J.; Venkataramania, H.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1996-03-01

    We have used the energy-energy angular pattern of hadrons in inelastic muon-deuteron scattering to study perturbative QCD effects and to extract the gluon distribution function ηG( η) of the nucleon, where η is the fractional momentum carried by the gluon. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 490 GeV. We present ηG( η) for 0.005< η<0.05 and at an average Q 2 of 8 GeV2 using this new technique. We find that ηG( η) in this region can be described by ηG( η) α ηλ with λ=-0.87±0.09( stat.)±{0.37/0.32}( sys.). We compare our results to expectations from various parametrizations of the parton distribution function and also to results from HERA.

  18. Rayleigh Scattering.

    ERIC Educational Resources Information Center

    Young, Andrew T.

    1982-01-01

    The correct usage of such terminology as "Rayleigh scattering,""Rayleigh lines,""Raman lines," and "Tyndall scattering" is resolved during an historical excursion through the physics of light-scattering by gas molecules. (Author/JN)

  19. Simultaneous observation of small- and large-energy-transfer electron-electron scattering in three-dimensional indium oxide thick films

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Liu, Xin-Dian; Li, Zhi-Qing

    2016-05-01

    In three-dimensional (3D) disordered metals, the electron-phonon (e-ph) scattering is the sole significant inelastic process. Thus the theoretical prediction concerning the electron-electron (e\\text-e) scattering rate 1/τ_\\varphi as a function of temperature T in 3D disordered metal has not been fully tested thus far, though it was proposed 40 years ago (Schmid A., Z. Phys., 271 (1974) 251). We report here the simultaneous observation of small- and large-energy-transfer e\\text-e scattering in 3D indium oxide thick films. In the temperature region T≳100 \\text{K} , the temperature dependence of resistivity of each film obeys Bloch-Grüneisen law, indicating that the films possess degenerate-semiconductor characteristics in electrical transport property. In the low-temperature regime, 1/τ_\\varphi as a function of T for each film can not be ascribed to e-ph scattering. To quantitatively describe the temperature behavior of 1/τ_\\varphi , both the 3D small- and large-energy-transfer e\\text-e scattering processes should be considered. (The small- and large-energy-transfer e\\text-e scattering rates are proportional to T3/2 and T 2, respectively.) In addition, the experimental prefactors of T3/2 and T 2 are proportional to k_F-5/2 \\ell-3/2 and E_F-1 (k F is the Fermi wave number, ℓ is the electron elastic mean free path, and E F is the Fermi energy), respectively, which are completely consistent with the theoretical predictions. Our experimental results fully demonstrate the validity of the theoretical predictions concerning both small- and large-energy-transfer e\\text-e scattering rates.

  20. Microscopic optical model potentials for p-nucleus scattering at intermediate energies

    SciTech Connect

    Hemalatha, M.; Gambhir, Y. K.; Kailas, S.; Haider, W.

    2007-03-15

    A comparative study of the microscopic optical potentials viz., semimicroscopic with extended Jeukenne-Lejeune-Mahaux interaction and microscopic Brueckner theory using Hamada-Johnston as well as Urbana V14 soft-core internucleon interactions, has been carried out. These microscopic optical potentials are compared with that of Dirac phenomenology (DP) for the polarized proton-{sup 40}Ca elastic scattering at 35 MeV and 200 MeV. These potentials have different shapes for 200 MeV below 4 fm. In particular, for the real part of the central potential, only the Dirac phenomenology and the microscopic optical potential calculated with the Hamada-Johnston interaction exhibit the well known wine-bottle-bottom shape. It is found that the calculated observables (cross section, analyzing power and spin rotation function) using these potentials having different shapes, compare well with the experiment.

  1. Internal Energy Dependence of Molecular Condensation Coefficients Determined from Molecular Beam Surface Scattering Experiments

    DOE R&D Accomplishments Database

    Sibener, S. J.; Lee, Y. T.

    1978-05-01

    An experiment was performed which confirms the existence of an internal mode dependence of molecular sticking probabilities for collisions of molecules with a cold surface. The scattering of a velocity selected effusive beam of CCl{sub 4} from a 90 K CC1{sub 4} ice surface has been studied at five translational velocities and for two different internal temperatures. At a surface temperature of 90 K (approx. 99% sticking probability) a four fold increase in reflected intensity was observed for the internally excited (560 K) CC1{sub 4} relative to the room temperature (298 K) CC1{sub 4} at a translational velocity of 2.5 X 10{sup 4} cm/sec. For a surface temperature of 90 K all angular distributions were found to peak 15{sup 0} superspecularly independent of incident velocity.

  2. Analysis of Elastic Scattering of 8He+208Pb System at around the Coulomb Barrier Energies

    NASA Astrophysics Data System (ADS)

    Direkci, M.; Kucuk, Y.; Boztosun, I.

    2015-04-01

    The elastic scattering angular distribution of 8He+208Pb system is investigated at Elab = 22.0 MeV within the framework of Optical Model by using phenomenological and microscopic potentials. For the phenomenological Optical Model calculations, both real and imaginary parts of the complex nuclear potential have been chosen to have the Wood-Saxon shape. In the microscopic Optical Model calculations, we have used double folding procedure to calculate the real part of optical potential for different kinds of density distributions of 8He. A comparative study of this system has been conducted for the fist time by using phenomenological and microscopic potentials. It is observed that large imaginary radius value due to the existence of long-range absorption mechanism acting at large distances provides a very good agreement between theoretical results and experimental data with small χ2/N values.

  3. Utilizing the CGC/saturation approach for soft scattering at high energies

    NASA Astrophysics Data System (ADS)

    Gotsman, E.

    2016-07-01

    We propose a consistent approach to describe soft interactions at LHC and higher energies based on the BFKL Pomeron and CGC/saturation. The Green function of the Pomeron is calculated in the framework of CGC/saturation approach. Having eight parameters we obtained a good description of the experimental data at high energies (W ≥ 0.546 TeV).

  4. Re-determination of bound state resonance energies in He/graphite scattering

    NASA Astrophysics Data System (ADS)

    Chung, S.; Kara, A.; Frankl, D. R.

    1986-05-01

    Binding energies of 4He atoms physisorbed on graphite (0001) surfaces were re-determined with improved resolution and precision. Energies are several tenths of an meV deeper than found in previous determinations, and an additional high-lying level is resolved. These results are in good agreement with recent theoretical calculations.

  5. Three energy scales in the superconducting state of hole-doped cuprates detected by electronic Raman scattering

    SciTech Connect

    Benhabib, S.; Gu, G. D.; Gallais, Y.; Cazayous, M.; Measson, M. -A.; Zhong, R. D.; Schneeloch, J.; Forget, A.; Colson, D.; Sacuto, A.

    2015-10-06

    We explore by electronic Raman scattering the superconducting state of the Bi2Sr2CaCu2O8+δ (Bi-2212) crystal by performing a fine-tuned doping study. We find three distinct energy scales in A1g, B1g, and B2g symmetries which show three distinct doping dependencies. Above p=0.22, the three energies merge; below p=0.12, the A1g scale is no longer detectable, while the B1g and B2g scales become constant in energy. In between, the A1g and B1g scales increase monotonically with underdoping, while the B2g one exhibits a maximum at p=0.16. The three superconducting energy scales appear to be a universal feature of hole-doped cuprates. Furthermore, we propose that the nontrivial doping dependencies of the three scales originate from the Fermi-surface changes and reveal competing orders inside the superconducting dome.

  6. Three energy scales in the superconducting state of hole-doped cuprates detected by electronic Raman scattering

    DOE PAGESBeta

    Benhabib, S.; Gu, G. D.; Gallais, Y.; Cazayous, M.; Measson, M. -A.; Zhong, R. D.; Schneeloch, J.; Forget, A.; Colson, D.; Sacuto, A.

    2015-10-06

    We explore by electronic Raman scattering the superconducting state of the Bi2Sr2CaCu2O8+δ (Bi-2212) crystal by performing a fine-tuned doping study. We find three distinct energy scales in A1g, B1g, and B2g symmetries which show three distinct doping dependencies. Above p=0.22, the three energies merge; below p=0.12, the A1g scale is no longer detectable, while the B1g and B2g scales become constant in energy. In between, the A1g and B1g scales increase monotonically with underdoping, while the B2g one exhibits a maximum at p=0.16. The three superconducting energy scales appear to be a universal feature of hole-doped cuprates. Furthermore, we proposemore » that the nontrivial doping dependencies of the three scales originate from the Fermi-surface changes and reveal competing orders inside the superconducting dome.« less

  7. Light-by-light scattering in ultraperipheral Pb-Pb collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Kłusek-Gawenda, Mariola; Lebiedowicz, Piotr; Szczurek, Antoni

    2016-04-01

    We calculate cross sections for diphoton production in (semi)exclusive PbPb collisions, relevant for the CERN Large Hadron Collider (LHC). The calculation is based on the equivalent photon approximation in the impact parameter space. The cross sections for the elementary γ γ →γ γ subprocess are calculated including two different mechanisms. We take into account box diagrams with leptons and quarks in the loops. In addition, we consider a vector-meson dominance (VDM-Regge) contribution with virtual intermediate hadronic (vector-like) excitations of the photons. We get measurable cross sections in PbPb collisions. This opens a possibility to study the γ γ →γ γ (quasi)elastic scattering at the LHC. We present many interesting differential distributions which could be measured by the ALICE, CMS, or ATLAS Collaborations at the LHC. We study whether a separation or identification of different components (boxes, VDM-Regge) is possible. We find that the cross section for elastic γ γ scattering could be measured in the heavy-ion collisions for subprocess energies smaller than Wγ γ≈15 -20 GeV.

  8. Highly sensitive determination of antimony in food by resonance Rayleigh scattering-energy transfer between grapheme oxide and I3(.).

    PubMed

    Wen, Guiqing; Zhang, Xinghui; Li, Yuan; Luo, Yanghe; Liang, Aihui; Jiang, Zhiliang

    2017-01-01

    Sb(III) was reduced to SbH3 gas and introduced to the I3(-)-grapheme oxide (GO) or I3(-)-silver nanorod (AgNR)-Victoria blue B (VBB) solutions. Resonance Rayleigh scattering energy transfer (RRS-ET) occurred between the donor GO and the acceptor I3(-) due to the overlap between the absorption peak of I3(-) and RRS peak of GO. When I3(-) was reduced by SbH3, RRS-ET weakened and the RRS intensity enhanced. The increased RRS intensity was linear to Sb concentration in the range of 2.1-376.6μg/L. In the I3(-)-AgNR-VBB solution, I3(-) combined with VBB to form VBB-I3 and there was a weak surface-enhanced Raman scattering (SERS) effect. When SbH3 reduced I3(-), the SERS intensity increased due to the release of SERS active VBB. The enhanced SERS intensity was linear for Sb concentration in the range of 8.4-292.9μg/L. The RRS-ET method was applied for determination of Sb in food with satisfactory results. PMID:27507443

  9. Low-Energy Grazing Ion-Scattering from Alkali-Halide Surfaces: A Novel Approach to C-14 Detection

    SciTech Connect

    Meyer, Fred W; Galutschek, Ernst; Hotchkis, Michael

    2009-01-01

    Carbon-14 labeled compounds are widely used in the pharmaceutical industry, e.g., as tracers to determine the fate of these compounds in vivo. Conventional accelerator mass spectrometry (AMS) is one approach that offers sufficiently high sensitivity to avoid radiological waste and contamination issues in such studies, but requires large, expensive facilities that are usually not solely dedicated to this task. At the ORNL Multicharged Ion Research Facility (MIRF) we are exploring a small size, low cost alternative to AMS for biomedical 14C tracer studies that utilizes ECR-ion-source-generated keV-energy-range multicharged C beams grazingly incident on an alkali halide target, where efficient negative ion production by multiple electron capture takes place. By using C ion charge states of +3 or higher, the molecular isobar interference at mass 14, e.g. 12CH2 and 13CH, is eliminated. The negatively charged ions in the beam scattered from the alkali halide surface are separated from other scattered charge states by two large acceptance ({approx}15 msr) stages of electrostatic analysis. The N-14 isobar interference is thus removed, since N does not support a stable negative ion. Initial results for C-14 detection obtained using C-14 enriched CO2 from ANSTO will be described.

  10. Theory of inelastic ion-atom scattering at low and intermediate energies

    NASA Technical Reports Server (NTRS)

    Schmid, G. B.; Garcia, J. D.

    1977-01-01

    Ab initio calculations are presented of inelastic energy loss and ionization phenomena associated with Ar(+)-Ar collisions at small distances of closest approach and for laboratory collision energies ranging from several keV to several hundred keV. Outer-shell excitations are handled statistically; inner-shell excitations are calculated from the viewpoint of quasidiabatic molecular orbital promotion. Auger electron yield, average state of ionization, and average inelastic energy loss are calculated per collision as a function of distance of closest approach of the collision partners for several laboratory collision energies. Average charge-state probabilities per collision partner are calculated as a function of the average inelastic energy loss per atom. It is shown that the structure in the data is due to the underlying structure in the inner-shell independent-electron quasimolecular promotion probabilities.

  11. Light Scattering as an Indicator of the Energy State in Leaves of the Crassulacean Acid Metabolism Plant Kalanchoë pinnata1

    PubMed Central

    Köster, Sigrid; Winter, Klaus

    1985-01-01

    Both transmittance changes in a weak beam of green light (light scattering) and the slow decay of chlorophyll a fluorescence were used as indicators of the energy state of leaves of a Crassulacean acid metabolism plant, Kalanchoë pinnata, at frequent intervals during 12-hour light/12-hour dark cycles. To induce light scattering and fluorescence changes, leaves were exposed to red light for 6 minutes. When measurements were made during the light period, the leaves were kept in darkness for 6 minutes before illumination. In the middle of the light period, when malic acid decarboxylation was very active and stomatal conductance was low, light scattering changes were small and indicated that the energy state of leaves was low. This result was supported by determination of adenylate levels. Light scattering and ATP/ADP ratios increased during the late light period when the tissue was deacidified. Illumination produced maximum light scattering changes between the 2nd and 5th hour of the dark period, when rates of dark CO2 fixation were highest. Light scattering and fluorescence measurements taken from leaves, which were illuminated with red or far-red light in the presence or absence of O2 showed that, in addition to linear electron transport, K. pinnata has the potential for both cyclic and pseudocyclic electron transport. The results are relevant with regard to the high ATP demand during Crassulacean acid metabolism. PMID:16664443

  12. Nonsymmetrized noise in a quantum dot: Interpretation in terms of energy transfer and coherent superposition of scattering paths

    NASA Astrophysics Data System (ADS)

    Zamoum, R.; Lavagna, M.; Crépieux, A.

    2016-06-01

    We calculate the nonsymmetrized current noise in a quantum dot connected to two reservoirs by using the nonequilibrium Green function technique. We show that both the current autocorrelator (inside a single reservoir) and the current cross-correlator (between the two reservoirs) are expressed in terms of transmission amplitude and coefficient through the barriers. We identify the different energy-transfer processes involved in each contribution to the autocorrelator, and we highlight the fact that when there are several physical processes, the contribution results from a coherent superposition of scattering paths. Varying the gate and bias voltages, we discuss the profile of the differential Fano factor in light of recent experiments, and we identify the conditions for having a distinct value for the autocorrelator in the left and right reservoirs.

  13. Measurement of the beam-recoil polarization in low-energy virtual Compton scattering from the proton

    NASA Astrophysics Data System (ADS)

    Doria, L.; Janssens, P.; Achenbach, P.; Ayerbe Gayoso, C.; Baumann, D.; Bensafa, I.; Benali, M.; Beričič, J.; Bernauer, J. C.; Böhm, R.; Bosnar, D.; Correa, L.; D'Hose, N.; Defaÿ, X.; Ding, M.; Distler, M. O.; Fonvieille, H.; Friedrich, J.; Friedrich, J. M.; Laveissière, G.; Makek, M.; Marroncle, J.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nungesser, L.; Pasquini, B.; Pochodzalla, J.; Postavaru, O.; Potokar, M.; Ryckbosch, D.; Sánchez Majos, S.; Schlimme, B. S.; Seimetz, M.; Širca, S.; Tamas, G.; Van de Vyver, R.; Van Hoorebeke, L.; Van Overloop, A.; Walcher, Th.; Weinriefer, M.; A1 Collaboration

    2015-11-01

    Double-polarization observables in the reaction e ⃗p →e'p ⃗'γ have been measured at Q2=0.33 (GeV/c ) 2 . The experiment was performed at the spectrometer setup of the A1 Collaboration using the 855 MeV polarized electron beam provided by the Mainz Microtron (MAMI) and a recoil proton polarimeter. From the double-polarization observables the structure function PLT ⊥ is extracted for the first time, with the value (-15.4 ±3 .3(stat .)-2.4+1.5(syst.)) GeV-2 , using the low-energy theorem for virtual Compton scattering. This structure function provides a hitherto unmeasured linear combination of the generalized polarizabilities of the proton.

  14. Structure determination of the CoSi2(111) surface using medium-energy ion scattering

    NASA Astrophysics Data System (ADS)

    Vrijmoeth, J.; Schins, A. G.; van der Veen, J. F.

    1989-08-01

    The surface structure of epitaxially grown CoSi2 crystals on Si(111) has been investigated with use of medium-energy ion scattering. A Co- or a Si-rich surface composition is obtained, depending on the preparation conditions. The structure of the Co-rich surface is shown to be bulklike, i.e., the crystal is terminated by a Si-Co-Si triple layer. The Si-rich surface is found to have, on top of the last Si-Co-Si triple layer, a Si double layer of the same orientation as the CoSi2 bulk lattice. This accounts for the difficulty to grow a 180°-rotated Si film on top of CoSi2(111) by normal molecular-beam-epitaxy techniques. The topmost Co atoms of the Si-rich surface are eightfold coordinated.

  15. Energy Distributions of Neutrons Scattered from Graphite, Light and Heavy Water, Ice, Zirconium Hydride, Lithium Hydride, Sodium Hydride and Ammonium Chloride by the Beryllium Detector Method

    DOE R&D Accomplishments Database

    Woods, A. D. B.; Brockhouse, Bertram N.; Sakamoto, M.; Sinclair, R. N.

    1960-09-12

    Energy distributions of neutrons scattered from various moderators and from several hydrogenous substances were measured at energy transfers of 0.02 to 0.24 ev. Results from experiments on graphite, light and heavy water, ice, ZrH, LiH, NaH, and NH4Cl are included. It is noted that the results are of a preliminary character; however, they are probably the most accurate measurements of high-energy transfers yet made. (J.R.D.)

  16. Scattering of NH{sub 3} and ND{sub 3} with rare gas atoms at low collision energy

    SciTech Connect

    Loreau, J.

    2015-11-14

    We present a theoretical study of elastic and rotationally inelastic collisions of NH{sub 3} and ND{sub 3} with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm{sup −1}. We focus on collisions in which NH{sub 3} is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an experimental context as it can be trapped electrostatically and Stark-decelerated. We discuss the presence of resonances in the elastic and inelastic cross sections, as well as the trends in the inelastic cross sections along the rare gas series and the differences between NH{sub 3} and ND{sub 3} as a colliding partner. We also demonstrate the importance of explicitly taking into account the umbrella (inversion) motion of NH{sub 3} in order to obtain accurate scattering cross sections at low collision energy. Finally, we investigate the possibility of sympathetic cooling of ammonia using cold or ultracold rare gas atoms. We show that some systems exhibit a large ratio of elastic to inelastic cross sections in the cold regime, which is promising for sympathetic cooling experiments. The close-coupling calculations are based on previously reported ab initio potential energy surfaces for NH{sub 3}–He and NH{sub 3}–Ar, as well as on new, four-dimensional, potential energy surfaces for the interaction of ammonia with Ne, Kr, and Xe, which were computed using the coupled-cluster method and large basis sets. We compare the properties of the potential energy surfaces corresponding to the interaction of ammonia with the various rare gas atoms.

  17. Resonant scattering and charm showers in ultrahigh-energy neutrino interactions

    NASA Technical Reports Server (NTRS)

    Wilczek, F.

    1985-01-01

    Electron antineutrinos with energy of about 7 x 10 to the 6th GeV have much-enhanced cross sections due to W-boson production off electrons. Possible signals due to cosmic-ray sources are estimated. Higher-energy antineutrinos can efficiently produce a W accompanied by radiation. Another possibility, which could lead to shadowing at modest depths, is resonant production of a charged Higgs particle. The importance of muon production by charm showers in rock is pointed out.

  18. Spectrally-selective all-inorganic scattering luminophores for solar energy-harvesting clear glass windows.

    PubMed

    Alghamedi, Ramzy; Vasiliev, Mikhail; Nur-E-Alam, Mohammad; Alameh, Kamal

    2014-01-01

    All-inorganic visibly-transparent energy-harvesting clear laminated glass windows are the most practical solution to boosting building-integrated photovoltaics (BIPV) energy outputs significantly while reducing cooling- and heating-related energy consumption in buildings. By incorporating luminophore materials into lamination interlayers and using spectrally-selective thin-film coatings in conjunction with CuInSe2 solar cells, most of the visible solar radiation can be transmitted through the glass window with minimum attenuation while ultraviolet (UV) radiation is down-converted and routed together with a significant part of infrared radiation to the edges for collection by solar cells. Experimental results demonstrate a 10 cm × 10 cm vertically-placed energy-harvesting clear glass panel of transparency exceeding 60%, invisible solar energy attenuation greater than 90% and electrical power output near 30 Wp/m(2) mainly generated by infrared (IR) and UV radiations. These results open the way for the realization of large-area visibly-transparent energy-harvesting clear glass windows for BIPV systems. PMID:25321890

  19. Low-Energy Excitations in the Second LL: Fundamental Insights from Inelastic Light Scattering

    NASA Astrophysics Data System (ADS)

    Wurstbauer, Ursula; Pinczuk, Aron; Levy, Antonio L.; Watson, John; Mondal, Sumit; Manfra, Michael J.; West, Ken; Pfeiffer, Loren

    2014-03-01

    The competition between quantum phases that dictates the physics in the second Landau level (SLL) results in striking phenomena. Our work explores this fascinating interaction physics by measurements of low-lying neutral excitation modes in the SLL from resonant inelastic light scattering experiments. We focus here on the marked differences of the low-lying collective excitation spectra of the even-denominator state at ν=5/2 with those in the range 5/2> ν>2. Filling factor 5/2 is characterized by the presence of gapped modes, a spin mode exactly at EZ and the absence of a continuum of low-lying excitations. In contrast, a continuum of low-lying excitations and gapped modes are coexistent at ν=2+1/3, 2+3/8 and 2+2/5 and the spin-modes appear significantly below EZ. All observed modes weakens with smallest variations in filling factor substantiating the transition from an incompressible quantum Hall fluid to compressible states. Supported by NSF and AvH.

  20. Incident energy and polarization-dependent resonant inelastic x-ray scattering study of La2CuO4

    NASA Astrophysics Data System (ADS)

    Lu, L.; Hancock, J. N.; Chabot-Couture, G.; Ishii, K.; Vajk, O. P.; Yu, G.; Mizuki, J.; Casa, D.; Gog, T.; Greven, M.

    2006-12-01

    We present a detailed Cu K -edge resonant inelastic x-ray scattering (RIXS) study of the Mott insulator La2CuO4 in the 1-7eV energy loss range. As initially found for the high-temperature superconductor HgBa2CuO4+δ , the spectra exhibit a multiplet of weakly dispersive electron-hole excitations, which are revealed by utilizing the subtle dependence of the cross section on the incident photon energy. The close similarity between the fine structures for in-plane and out-of-plane polarizations is indicative of the central role played by the 1s core hole in inducing charge excitations within the CuO2 planes. On the other hand, we observe a polarization dependence of the spectral weight, and careful analysis reveals two separate features near 2eV that may be related to different charge-transfer processes. The polarization dependence indicates that the 4p electrons contribute significantly to the RIXS cross section. Third-order perturbation arguments and a shake-up of valence excitations are then applied to account for the final-energy resonance in the spectra. As an alternative scenario, we discuss fluorescence-like emission processes due to 1s→4p transitions into a narrow continuum 4p band.

  1. Quasielastic /sup 3/Hp and /sup 3/Hep scattering at intermediate energies and the Glauber sum rules

    SciTech Connect

    Blinov, A.V.; Vanyushin, I.A.; Grechko, V.E.; Drobot, V.V.; Ergakov, B.A.; Zombkovskii, S.M.; Kondratyuk, L.A.; Korolev, Y.V.; Selektor, Y.M.; Solov'ev, V.V.

    1984-09-01

    The differential cross sections and the average energy loss of fast protons in the reactions p+/sup 3/H..-->..p/sub F/+X and p+/sup 3/He..-->..p/sub F/+X are investigated by means of a liquid-hydrogen bubble chamber at the Institute of Theoretical and Experimental Physics of diameter 80 cm, exposed in a beam of 2.5 GeV/c tritium nuclei (primary-proton kinetic energy in the rest system of the nucleus T/sub p/ = 0.318 GeV) and in a beam of 5-GeV/c /sup 3/He nuclei (T/sub p/ = 0.978 GeV). The experimental results are compared with the predictions based on sum rules for differential cross sections and average energy loss in the Glauber-Sitenko theory of multiple scattering and with use of the completeness condition for the wave functions of the excited states of the nucleus and locality of the nuclear potential. Good agreement between the data and the theoretical predictions is observed at 2.5 GeV/c. A discrepancy between the Glauber sum-rule predictions and the data at 5 GeV/c is explained by the production of the ..delta.. isobar in the intermediate state. It is established that the possible admixture of six-quark bags in the nuclei /sup 3/H and /sup 3/He does not exceed 5%.

  2. Numerical simulations for width fluctuations in compound elastic and inelastic scattering at low energies

    SciTech Connect

    Kawano, Toshihiko; Talou, Patrick

    2012-09-18

    The statistical theories - the Hauser-Feshbach model with the width fluctuation correction - play a central role in studying nuclear reactions in the fast energy region, hence the statistical model codes are essential for the nuclear data evaluations nowadays. In this paper, we revisit issues regarding the statistical model calculations in the fast energy range, such as the inclusion of the direct channels, and the energy averaged cross sections using different statistical assumptions. Although they have been discussed for a long time, we need more precise quantitative investigations to understand uncertainties coming from the models deficiencies in the fast energy range. For example, the partition of compound formation cross section into the elastic and inelastic channels depends on the elastic enhancement factor calculated from the statistical models. In addition, unitarity of S-matrix constrains this partition when the direct reactions are involved. Practically some simple assumptions, which many nuclear reaction model codes adopt, may work reasonably for the nuclear data evaluations. However, the uncertainties on the evaluated cross sections cannot go lower than the model uncertainty itself. We perform numerical simulations by generating the resonances using the R-matrix theory, and compare the energy (ensemble) averaged cross sections with the statistical theories, such as the theories of Moldauer, HRTW (Hofmann, Richert, Tepel, and Weidenmueller), KKM (Kawai-Kerman-McVoy), and GOE (Gaussian orthogonal ensemble).

  3. Measurements and calculations of neutron scattering angular distributions over a wide mass and energy range

    SciTech Connect

    Hansen, L.F.

    1985-05-01

    Neutron elastic and inelastic differential cross sections for targets between /sup 9/Be and /sup 239/Pu at energies, E > 14 MeV have been measured using the Livermore and Ohio University neutron time-of-flight facilities. We review here the data and the analyses based on two local microscopic optical potentials: that of Jeukenne, Lejeune and Mahaux, and that of Brieva and Rook. The results are also compared with calculations using global potentials. Coupled channel formalism has been used in the analysis of targets with strong deformations, such as Be, C, Ta, and actinides. The value of the microscopic optical potentials as a tool to predict elastic and inelastic neutron cross sections over a wide mass and energy range is discussed. The need for neutron measurements up to higher energies and their analysis in conjunction with (p,p) and charge exchange (p,n) data is addressed. 17 refs.

  4. Measurements and Calculations of Neutron Scattering Angular Distributions over a Wide Mass and Energy Range

    NASA Astrophysics Data System (ADS)

    Hansen, L. F.

    Neutron elastic and inelastic differential cross sections for targets between (9)Be and (239)Pu at energies, E 14 MeV have been measured using the Livermore and Ohio University neutron time-of-flight facilities. We review here the data and the analyses based on two local microscopic optical potentials: that of Jeukenne, Lejeune and Mahaux, and that of Brieva and Rook. The results are also compared with calculations using global potentials. Coupled channel formalism has been used in the analysis of targets with strong deformations, such as Be, C, Ta, and actinides. The value of the microscopic optical potentials as a tool to predict elastic and inelastic neutron cross sections over a wide mass and energy range is discussed. The need for neutron measurements up to higher energies and their analysis in conjunction with (p,p) and charge exchange (p,n) data is addressed.

  5. Elastic scattering of low-energy electrons by 1,4-dioxane

    SciTech Connect

    Barbosa, Alessandra Souza; Bettega, Márcio H. F.

    2014-05-14

    We report calculated cross sections for elastic collisions of low-energy-electrons with 1,4-dioxane. Our calculations employed the Schwinger multichannel method with pseudopotentials and were carried out in the static-exchange and static-exchange plus polarization approximations for energies up to 30 eV. Our results show the presence of three shape resonances belonging to the B{sub u}, A{sub u}, and B{sub g} symmetries and located at 7.0 eV, 8.4 eV, and 9.8 eV, respectively. We also report the presence of a Ramsauer-Townsend minimum located at around 0.05 eV. We compare our calculated cross sections with experimental data and R-matrix and independent atom model along with the additivity rule corrected by using screening coefficients theoretical results for 1,4-dioxane obtained by Palihawadana et al. [J. Chem. Phys. 139, 014308 (2013)]. The agreement between the present and the R-matrix theoretical calculations of Palihawadana et al. is relatively good at energies below 10 eV. Our calculated differential cross sections agree well with the experimental data, showing only some discrepancies at higher energies.

  6. Elastic scattering of low-energy electrons by 1,4-dioxane

    NASA Astrophysics Data System (ADS)

    Barbosa, Alessandra Souza; Bettega, Márcio H. F.

    2014-05-01

    We report calculated cross sections for elastic collisions of low-energy-electrons with 1,4-dioxane. Our calculations employed the Schwinger multichannel method with pseudopotentials and were carried out in the static-exchange and static-exchange plus polarization approximations for energies up to 30 eV. Our results show the presence of three shape resonances belonging to the Bu, Au, and Bg symmetries and located at 7.0 eV, 8.4 eV, and 9.8 eV, respectively. We also report the presence of a Ramsauer-Townsend minimum located at around 0.05 eV. We compare our calculated cross sections with experimental data and R-matrix and independent atom model along with the additivity rule corrected by using screening coefficients theoretical results for 1,4-dioxane obtained by Palihawadana et al. [J. Chem. Phys. 139, 014308 (2013)]. The agreement between the present and the R-matrix theoretical calculations of Palihawadana et al. is relatively good at energies below 10 eV. Our calculated differential cross sections agree well with the experimental data, showing only some discrepancies at higher energies.

  7. Modelization For Electromagnetic Electron Scattering at Low Energies for Radiotherapy applications.

    NASA Astrophysics Data System (ADS)

    Nazaryan, Vahagn; Gueye, Paul

    2006-03-01

    Since release of the GEANT4 particle simulation toolkit in 2003, there has been a growing interest in its applications to medical physics. The applicability of GEANT4 to radiotherapy has been a subject of several investigations in recent years, and it was found to be of great use. Its low-energy model allows for electromagnetic interaction simulations down to 250 eV. The electron physics data are obtained from the Lawrence Livermore National Laboratory's Evaluated Electron Data Library (EEDL). At very lower energies (below 10 MeV), some of the tabulated data in EEDL have big uncertainties (more than 50%), and rely on various extrapolations to energy regions where there is no experimental data. We have investigated the variations of these cross-section data to radiotherapy applications. Our study suggests a strong need for better theoretical models of electron interactions with matter at these energies, and the necessity of new and more reliable experimental data. The progress towards such theoretical model will be presented.

  8. New opportunities for quasielastic and inelastic neutron scattering at steady-state sources using mechanical selection of the incident and final neutron energy

    DOE PAGESBeta

    Mamantov, Eugene

    2015-06-12

    We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of themore » scattering angle component out of the equatorial plane.« less

  9. New opportunities for quasielastic and inelastic neutron scattering at steady-state sources using mechanical selection of the incident and final neutron energy

    SciTech Connect

    Mamantov, Eugene

    2015-06-12

    We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of the scattering angle component out of the equatorial plane.

  10. Unified dispersive approach to real and virtual photon-photon scattering at low energy

    NASA Astrophysics Data System (ADS)

    Moussallam, B.

    2013-09-01

    Previous representations of pion-pair production amplitudes by two real photons at low energy, which combine dispersion theoretical constraints with elastic unitarity, chiral symmetry and soft-photon constraints are generalised to the case where one photon is virtual. The constructed amplitudes display explicitly the dependence on the ππ phase-shifts, on pion form factors and on pion polarisabilities. They apply both for space-like and time-like virtualities despite the apparent overlap of the left- and right-hand cuts, by implementing a definition of resonance exchange amplitudes complying with analyticity and consistent limiting prescriptions for the energy variables. Applications are made to the pion generalised polarisabilies, to vector-meson radiative decays, and to the σγ electromagnetic form factor. Finally, an evaluation of the contribution of γππ states in the hadronic vacuum polarisation to the muon g-2 is given, which should be less model dependent than previous estimates.

  11. Low-energy electron elastic scattering from Mn, Cu, Zn, Ni, Ag, and Cd atoms

    SciTech Connect

    Felfli, Z.; Msezane, A. Z.; Sokolovski, D.

    2011-05-15

    Electron elastic total cross sections (TCSs) for ground and excited Mn, Cu, Zn, Ni, Ag, and Cd atoms have been investigated in the electron-impact energy range 0 {<=}E{<=} 1 eV. The near-threshold TCSs for both the ground and excited states of these atoms are found to be characterized by Ramsauer-Townsend minima, shape resonances, and extremely sharp resonances corresponding to the formation of stable bound negative ions. The recently developed Regge-pole methodology where the crucial electron-electron correlations are embedded is employed for the calculations. From close scrutiny of the imaginary parts of the complex angular momenta, we conclude that these atoms form stable weakly bound ground and excited negative ions as Regge resonances through slow electron collisions. The extracted electron binding energies from the elastic TCSs of these atoms are contrasted with the available experimental and theoretical values.

  12. Wetting transition in liquid Ga Bi alloys: light scattering study of surface energy and entropy

    NASA Astrophysics Data System (ADS)

    Ayyad, A. H.; Freyland, W.

    2002-05-01

    We have studied the surface energy, surface entropy and, partly, have received an estimate of the viscosity of liquid Ga-Bi alloys at compositions mainly in the Ga-rich phase region and at temperatures up to 620 K. Measurements have been performed by the noninvasive method of capillary wave spectroscopy which has been applied for the first time to investigate the surface properties of a liquid alloy at high temperatures. Analysis of the concentration dependence of the surface energy according to the Gibbs adsorption equation yields that in the composition range of 10 -2≲ xBi≲10 -1 and at temperatures of 450 K≲ T≲500 K a surface excess of ΓBi˜1.36×10 -5 mol m -2 resides at the liquid-vapour interface corresponding to pure Bi. At lower xBi a reduction of ΓBi occurs which is indicative of a prewetting transition. The variations of surface energy and entropy with composition are not consistent with a description by a simple monolayer model as was deduced from X-ray reflectivity results. Instead it is found that a multilayer model qualitatively accounts for the characteristic change of the surface quantities. The thickness of the multilayer interfacial region is estimated from the change of the relative surface entropy. This yields values between 10 and 20 Å with a trend for an increasing number of surface layers towards the complete wetting transition at the monotectic point. All isopleths of the surface energy exhibit clear kinks at temperatures 10-20 K above the liquidus curve for compositions below the monotectic point. The corresponding discontinuity of the surface entropy is consistent with a first order transition of surface freezing reported recently for the Ga-Bi system.

  13. Mapping the deformation in the "island of inversion": Inelastic scattering of 30Ne and 36Mg at intermediate energies

    NASA Astrophysics Data System (ADS)

    Doornenbal, P.; Scheit, H.; Takeuchi, S.; Aoi, N.; Li, K.; Matsushita, M.; Steppenbeck, D.; Wang, H.; Baba, H.; Ideguchi, E.; Kobayashi, N.; Kondo, Y.; Lee, J.; Michimasa, S.; Motobayashi, T.; Poves, A.; Sakurai, H.; Takechi, M.; Togano, Y.; Yoneda, K.

    2016-04-01

    The transition strengths of the first-excited 2+ states and deformation lengths of the nuclei 30Ne and 36Mg were determined via Coulomb- and nuclear-force-dominated inelastic scattering at intermediate energies. Beams of these exotic nuclei were produced at the RIKEN Radioactive Isotope Beam Factory and were incident on lead and carbon targets at energies above 200 MeV/u . Absolute excitation cross sections on the lead target yielded reduced transition probabilities of 0.0277(79) and 0.0528(121) e2b2 , while the measurements with the carbon target revealed nuclear deformation lengths of δN=1.98 (11) and 1.93(11) fm for 30Ne and 36Mg, respectively. Corresponding quadrupole deformation parameters of β2˜0.5 from the two probes were found comparable in magnitude, showing no indication for a reduction in deformation along isotopic and isotonic chains from 32Mg towards the neutron drip-line. Comparisons to shell-model calculations illustrate the importance of neutron excitations across the N =20 shell for 30Ne and suggest that shallow maximums of collectivity may occur around N =22 and 24 along the neon and magnesium isotopic chains, respectively.

  14. The effect of detector size and energy resolution on image quality in multi-projection Compton scatter tomography.

    PubMed

    Chighvinadze, Tamar; Pistorius, Stephen

    2014-01-01

    The reconstructed electron density image quality is sensitive to the detector size and energy resolution, which contribute to the blurring and noise in the image. This work evaluates optimal values of the detector parameters for a realistic system through analytical simulations of the transverse slice of the dedicated breast CT system geometry. This study introduces a spectroscopic x-ray tomography technique which uses multiple projections to reconstruct electron density images by backprojecting scattered photons over isogonic curves. The reconstruction can be obtained using a single projection yet its quality degrades as the acquisition conditions i.e. detector size and energy resolution deviate from the ideal. The reconstruction quality becomes inconsistent throughout the image due to the data under sampling caused by the finite resolution of the detector. The extension to the multi-projection mode effectively fills-in the missing data space and improves the ability to reconstruct an object. This work demonstrates the possibility to obtain images in the presence of noise. PMID:24463390

  15. (A neutron scattering experiment to study the high-energy spin dynamics of the itinerant antiferromagnet Mn sub 90 Cu sub 10 )

    SciTech Connect

    Fernandez-Baca, J.A.

    1990-10-26

    The traveler performed a neutron scattering experiment to study the high-energy spin dynamics of the itinerant antiferromagnet. This experiment was conducted at a unique instrument located at the hot-neutron source at the ILL. The traveler also held various scientific discussions with ILL research staff members and visiting scientists.

  16. Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses

    SciTech Connect

    Babenko, V. A. Petrov, N. M.

    2007-04-15

    The triplet and singlet low-energy parameters in the effective-range expansion for neutron-proton scattering are determined by using the latest experimental data on respective phase shifts from the SAID nucleon-nucleon database. The results differ markedly from the analogous parameters obtained on the basis of the phase shifts of the Nijmegen group and contradict the parameter values that are presently used as experimental ones. The values found with the aid of the phase shifts from the SAID nucleon-nucleon database for the total cross section for the scattering of zero-energy neutrons by protons, {sigma}{sub 0} = 20.426 b, and the neutron-proton coherent scattering length, f = -3.755 fm, agree perfectly with experimental cross-section values obtained by Houk, {sigma}{sub 0} = 20.436 {+-} 0.023 b, and experimental scattering-length values obtained by Houk and Wilson, f = -3.756 {+-} 0.009 fm, but they contradict cross-section values of {sigma}{sub 0} = 20.491 {+-} 0.014 b according to Dilg and coherent-scattering-length values of f = -3.7409 {+-} 0.0011 fm according to Koester and Nistler.

  17. Coherent anti-Stokes Raman scattering (CARS) detection or hot atom reaction product internal energy distributions

    SciTech Connect

    Quick, C.R. Jr.; Moore, D.S.

    1983-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is being utilized to investigate the rovibrational energy distributions produced by reactive and nonreactive collisions of translationally hot atoms with simple molecules. Translationally hot H atoms are produced by ArF laser photolysis of HBr. Using CARS we have monitored, in a state-specific and time-resolved manner, rotational excitation of HBr (v = 0), vibrational excitation of HBr and H/sub 2/, rovibrational excitation of H/sub 2/ produced by the reaction H + HBr ..-->.. H/sub 2/ + Br, and Br atom production by photolysis of HBr.

  18. Positron-rubidium scattering

    NASA Technical Reports Server (NTRS)

    Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.

    1990-01-01

    A 5-state close-coupling calculation (5s-5p-4d-6s-6p) was carried out for positron-Rb scattering in the energy range 3.7 to 28.0 eV. In contrast to the results of similar close-coupling calculations for positron-Na and positron-K scattering the (effective) total integrated cross section has an energy dependence which is contrary to recent experimental measurements.

  19. [ital Q][sup 2] dependence of the average squared transverse energy of jets in deep-inelastic muon-nucleon scattering with comparison to perturbative QCD predictions

    SciTech Connect

    Adams, M.R.; Arndotied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kirk, T.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schueler, K.P.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; S

    1994-01-24

    The average squared transverse energy of jets in deep-inelastic muon-nucleon scattering is measured as a function of the momentum transfer squared ([ital Q][sup 2]), in the range 3[lt][ital Q][sup 2][lt]25 GeV[sup 2]. Perturbative QCD predicts that the average squared parton transverse energy will depend upon the strong coupling constant ([alpha][sub [ital S

  20. The utility of x-ray dual-energy transmission and scatter technologies for illicit material detection

    NASA Astrophysics Data System (ADS)

    Lu, Qiang

    1999-12-01

    X-ray devices have demonstrated the ability to characterize a material at the molecular and atomic levels. This ability is particularly important for detecting plastic explosives, where object shape information cannot be used. X-ray devices are relatively inexpensive compared to many other detection technologies. X-ray technology is considered as the technology for detecting illicit materials. Using x-ray technology, a material's density- and effective atomic number or Zeff-related information can be determined. In theory, an illicit material can be identified using those two pieces of information. This dissertation discusses explosives detection in passenger luggage bags. The x-ray technology used is called R-L multi-sensing technology. The R-L technology was developed by researchers at Virginia Tech. It is the first true multi- sensing technology used for explosive detection. It uses dual-energy transmission and scatter technologies to obtain characteristic values of an object, i.e., R and L. The material type of this object can then be determined using R- L plane. The characteristic value R is computed using signals from dual- energy transmission modality. R is related to Zeff. The characteristic value L is computed using signals from low-energy transmission and scatter modalities. L is related to density. Compared to single-sensing technologies and pseudo multi- sensing technologies, the detection accuracy of R-L technology should be much higher. The R and L values of an object can only be computed from an object's true gray levels. True gray level refers to the measured gray level of an object when it is not overlapped with any other objects. The problem is objects in a bag almost always overlap with other objects. Being able to identify the object of interest and remove the overlap effects becomes the key issue that needs to be solved. The discussion in this dissertation focuses on the development of the image-processing system used on this multiple sensor

  1. On the design of experiments for determining ternary mixture free energies from static light scattering data using a nonlinear partial differential equation

    PubMed Central

    Wahle, Chris W.; Ross, David S.; Thurston, George M.

    2012-01-01

    We mathematically design sets of static light scattering experiments to provide for model-independent measurements of ternary liquid mixing free energies to a desired level of accuracy. A parabolic partial differential equation (PDE), linearized from the full nonlinear PDE [D. Ross, G. Thurston, and C. Lutzer, J. Chem. Phys. 129, 064106 (2008)10.1063/1.2937902], describes how data noise affects the free energies to be inferred. The linearized PDE creates a net of spacelike characteristic curves and orthogonal, timelike curves in the composition triangle, and this net governs diffusion of information coming from light scattering measurements to the free energy. Free energy perturbations induced by a light scattering perturbation diffuse along the characteristic curves and towards their concave sides, with a diffusivity that is proportional to the local characteristic curvature radius. Consequently, static light scattering can determine mixing free energies in regions with convex characteristic curve boundaries, given suitable boundary data. The dielectric coefficient is a Lyapunov function for the dynamical system whose trajectories are PDE characteristics. Information diffusion is heterogeneous and system-dependent in the composition triangle, since the characteristics depend on molecular interactions and are tangent to liquid-liquid phase separation coexistence loci at critical points. We find scaling relations that link free energy accuracy, total measurement time, the number of samples, and the interpolation method, and identify the key quantitative tradeoffs between devoting time to measuring more samples, or fewer samples more accurately. For each total measurement time there are optimal sample numbers beyond which more will not improve free energy accuracy. We estimate the degree to which many-point interpolation and optimized measurement concentrations can improve accuracy and save time. For a modest light scattering setup, a sample calculation shows that

  2. High-energy magnetic excitations in overdoped La2 -xSrxCuO4 studied by neutron and resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Wakimoto, S.; Ishii, K.; Kimura, H.; Fujita, M.; Dellea, G.; Kummer, K.; Braicovich, L.; Ghiringhelli, G.; Debeer-Schmitt, L. M.; Granroth, G. E.

    2015-05-01

    We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L3 edge to study high-energy magnetic excitations at energy transfers of more than 100 meV for overdoped La2 -xSrxCuO4 with x =0.25 (Tc=15 K) and x =0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic excitations up to ˜250 meV for x =0.25 . Although the width in the momentum direction is large, the peak positions along the (π ,π ) direction agree with the dispersion relation of the spin wave in the nondoped La2CuO4 (LCO), which is consistent with the previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π ,π ) and (π ,0 ) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π ,0 ) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π ,π ) direction probed by RIXS appears to be less dispersive and the excitation energy is lower than the spin wave of LCO near (π /2 ,π /2 ) . Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic excitation in the (π ,π ) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge excitations exist in the same energy range of magnetic excitations, reflecting the itinerant character of the overdoped sample. A possible anisotropy in the charge excitation intensity might explain the apparent differences in the paramagnon dispersion in the (π ,π ) direction as detected by the x-ray scattering.

  3. Polarization phenomena in nucleon-nucleon scattering at intermediate and high energies including the present status of dibaryons

    SciTech Connect

    Yokosawa, A.

    1985-01-01

    We review experimental results concerning polarization phenomena in nucleon-nucleon scattering in which both the elastic scattering and hadron-production reaction are included. We also present summary of S = 0 dibaryon resonances and candidates by reviewing experimental data in the nucleon-nucleon system, ..gamma..d channel, ..pi..d elastic scattering, pp ..-->.. ..pi..d channel, deuteron break-up reactions, and narrow structures in missing-mass spectra. 93 refs., 26 figs.

  4. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces

    SciTech Connect

    Warehime, Mick; Kłos, Jacek; Alexander, Millard H.

    2015-01-21

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F({sup 2}P) + HCl and F({sup 2}P) + H{sub 2} reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use.

  5. Elastic scattering of electrons from CO2 in the intermediate energy range

    NASA Astrophysics Data System (ADS)

    Iga, I.; Nogueira, J. C.; Mu-Tao, L.

    1984-03-01

    Ratios of elastic differential cross sections of CO2 to those of N2 have been measured at electron impact energies of 500, 800 and 1000 eV in the angular range of 5 deg to 120 deg, using a crossed electron-beam-molecular-beam geometry and the relative flow technique. These ratios have been multiplied by previously known N2 elastic differential cross sections to obtain elastic differential cross sections for CO2. At 500 eV, experimental results agree quite well with the absolute values of Bromberg (1974). Comparison has also been made with the theoretical results obtained in the renormalized multicenter potential model approach of Botelho et al. (1983) and shows an agreement within 20 percent in the entire angular range. The elastic integral and momentum transfer cross sections have also been determined from the differential cross sections.

  6. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Warehime, Mick; Kłos, Jacek; Alexander, Millard H.

    2015-01-01

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F(2P) + HCl and F(2P) + H2 reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use.

  7. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces.

    PubMed

    Warehime, Mick; Kłos, Jacek; Alexander, Millard H

    2015-01-21

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F((2)P) + HCl and F((2)P) + H2 reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use. PMID:25612690

  8. Energy Dependence of Nuclear Transparency in C (p,2p) Scattering

    NASA Astrophysics Data System (ADS)

    Leksanov, A.; Alster, J.; Asryan, G.; Averichev, Y.; Barton, D.; Baturin, V.; Bukhtoyarova, N.; Carroll, A.; Heppelmann, S.; Kawabata, T.; Makdisi, Y.; Malki, A.; Minina, E.; Navon, I.; Nicholson, H.; Ogawa, A.; Panebratsev, Yu.; Piasetzky, E.; Schetkovsky, A.; Shimanskiy, S.; Tang, A.; Watson, J. W.; Yoshida, H.; Zhalov, D.

    2001-11-01

    The transparency of carbon for (p,2p) quasielastic events was measured at beam momenta ranging from 5.9 to 14.5 GeV/c at 90° c.m. The four-momentum transfer squared (Q2) ranged from 4.7 to 12.7 (GeV/c)2. We present the observed beam momentum dependence of the ratio of the carbon to hydrogen cross sections. We also apply a model for the nuclear momentum distribution of carbon to obtain the nuclear transparency. We find a sharp rise in transparency as the beam momentum is increased to 9 GeV/c and a reduction to approximately the Glauber level at higher energies.

  9. Energy dissipation in heavy systems: the transition from quasi-elastic to deep-inelastic scattering

    SciTech Connect

    Rehm, K.E.; van den Berg, A.; Kolata, J.J.; Kovar, D.G.; Kutschera, W.; Rosner, G.; Stephans, G.S.F.; Yntema, J.L.; Lee, L.L.

    1984-01-01

    The interaction of medium mass projectiles (A = 28 - 64) with /sup 208/Pb has been studied using a split-pole spectrograph which allows single mass and charge identification. The reaction process in all systems studied so far is dominated by quasi-elastic neutron transfer reactions, especially at incident energies in the vicinity of the Coulomb barrier. In addition to the quasi-elastic component deep inelastic contributions are present in all reaction channels. The good mass and charge separation allows to generate Wilczynski plots for individual channels; for the system /sup 48/Ti + /sup 208/Pb we observe that the transition between the quasi-elastic and deep-inelastic reactions occurs around Q = -(30 to 35) MeV.

  10. Energy dependence of nuclear transparency in C (p,2p) scattering.

    PubMed

    Leksanov, A; Alster, J; Asryan, G; Averichev, Y; Barton, D; Baturin, V; Bukhtoyarova, N; Carroll, A; Heppelmann, S; Kawabata, T; Makdisi, Y; Malki, A; Minina, E; Navon, I; Nicholson, H; Ogawa, A; Panebratsev, Y; Piasetzky, E; Schetkovsky, A; Shimanskiy, S; Tang, A; Watson, J W; Yoshida, H; Zhalov, D

    2001-11-19

    The transparency of carbon for (p,2p) quasielastic events was measured at beam momenta ranging from 5.9 to 14.5 GeV/c at 90 degrees c.m. The four-momentum transfer squared (Q2) ranged from 4.7 to 12.7 (GeV/c)(2). We present the observed beam momentum dependence of the ratio of the carbon to hydrogen cross sections. We also apply a model for the nuclear momentum distribution of carbon to obtain the nuclear transparency. We find a sharp rise in transparency as the beam momentum is increased to 9 GeV/c and a reduction to approximately the Glauber level at higher energies. PMID:11736334

  11. Microscopic description of {sup 4}He + {sup 4}He elastic scattering over the energy range E=100-280 MeV

    SciTech Connect

    El-Azab Farid, M.

    2006-12-15

    Analysis of the differential cross sections for {sup 4}He +{sup 4}He elastic scattering is performed within the framework of the double-folding optical model. Two appropriate effective nucleon-nucleon interactions are employed to generate the {alpha}-{alpha} folded real potentials. The obtained potentials in conjunction with phenomenological Woods-Saxon (WS) derivative imaginary potentials are used to investigate six sets of the elastic scattering data through the energy range 100-280 MeV. Successful reproduction of the data is obtained by both considered interactions. In addition, real phenomenological potentials expressed in a squared WS form are successfully used to reproduce these data.

  12. High-Energy-Resolution Inelastic Electron and Proton Scattering and the Multiphonon Nature of Mixed-Symmetry 2{sup +} States in {sup 94}Mo

    SciTech Connect

    Burda, O.; Kuhar, M.; Lenhardt, A.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Botha, N.; Fearick, R. W.; Carter, J.; Sideras-Haddad, E.; Foertsch, S. V.; Neveling, R.; Smit, F. D.; Fransen, C.; Fujita, H.; Holt, J. D.; Pietralla, N.; Scholten, O.

    2007-08-31

    High-energy-resolution inelastic electron scattering (at the S-DALINAC) and proton scattering (at iThemba LABS) experiments permit a thorough test of the nature of proposed one- and two-phonon symmetric and mixed-symmetric 2{sup +} states of the nucleus {sup 94}Mo. The combined analysis reveals the one-phonon content of the mixed-symmetry state and its isovector character suggested by microscopic nuclear model calculations. The purity of two-phonon 2{sup +} states is extracted.

  13. An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate

    NASA Astrophysics Data System (ADS)

    Gontrani, Lorenzo; Russina, Olga; Marincola, Flaminia Cesare; Caminiti, Ruggero

    2009-12-01

    In this work, we report on the first x-ray diffraction study on liquid dimethyl carbonate. Diffraction spectra were collected with an energy-dispersive instrument, whose wide Q-range allows the structure determination of weakly ordered systems (such as liquids). The structural correlation in this liquid ranges up to about 20 Å. The observed patterns are interpreted with a structural model derived from classical molecular dynamics simulations. The simulations were run using OPLS force field, only slightly modified to restrain bond distances to the experimental values. The model structure function and radial distribution functions, averaged among the productive trajectory frames, are in very good agreement with the corresponding experimental ones. Molecular dynamics results show that the deviations from C2v cis-cis structure, predicted by ab initio calculations and observed by electron diffraction in the gas phase, are small. By analyzing the intra- and intermolecular pair distribution functions, it was possible to assign the peaks of the experimental radial distribution function to specific structural correlations, and to compute the different average intermolecular coordination numbers. The intermolecular methyl-carbonyl oxygen distance is thoroughly discussed to assess the presence of weak C-H⋯ṡO hydrogen bonds.

  14. High-Intensity Scattering Processes of Relativistic Electrons in Vacuum and Their Relevance to High-Energy Astrophysics

    SciTech Connect

    Hartemann, Frederic V.; Troha, Anthony L.; Baldis, Hector A.; Gupta, Atul; Kerman, Arthur K.; Landahl, Eric C.; Luhmann, Neville C. Jr.; Van Meter, James R.

    2000-04-01

    The recent advent of ultra-short pulse, high-intensity lasers, together with advances in other novel technologies, such as high-gradient radiofrequency photoinjectors, have afforded researchers the possibility to simulate astrophysical conditions in the laboratory. Laser-produced plasmas have been successfully used to simulate astrophysical plasmas and supernovae in the laboratory for several years. Now, femtosecond laser systems operating in the terawatt to petawatt range are available, as are synchronized relativistic electron bunches with subpicosecond durations and terahertz bandwidths. With these tools, experiments have been conducted to study phenomena related to supernova explosions, stellar winds, solar coronae, cosmic rays, planetary and celestial matter, and interstellar plasmas. Other experiments have been proposed to investigate Unruh radiation, as well as ponderomotive scattering, which can accelerate electrons in vacuum to relativistic energies using the extremely high gradients in a three-dimensional laser focus. The nonlinear Doppler shift induced by ultrarelativistic radiation pressure is shown to yield complex nonlinear Compton backscattered spectra. Finally, strong radiative corrections are expected when the Doppler-upshifted laser wavelength approaches the Compton scale. These are discussed within the context of high-field classical electrodynamics, a new discipline borne out of the aforementioned innovations. (c) 2000 The American Astronomical Society.

  15. Channeling energy loss of He 2+ in Si by transmission and back-scattering measurements: Experiments and computer modeling

    NASA Astrophysics Data System (ADS)

    Lulli, G.; Albertazzi, E.; Bentini, G. G.; Bianconi, M.; Lotti, R.

    2002-06-01

    Path-dependent electronic stopping of 3.35 MeV He 2+ ions in Si, is investigated by Rutherford back-scattering channeling in Si/SiO 2 wafers and transmission energy loss measurements in thin (1 1 0) membranes. A model which makes use of the 3-D Si electron density to calculate the stopping due to valence electrons, and the program convolution approximation for swift particles (CASP) to calculate the stopping due to core electrons, has been introduced into a Monte Carlo code for the simulation of channeling. The only adjustment allowed is the normalization to the empirical random stopping. An agreement of simulations and experiments within ±10-15% is obtained if both valence and core electron stopping components are scaled in the normalization procedure. To perform a significant comparison with the results obtained by a full atomic (CASP) model, we have also used a different normalization scheme, keeping the core component fixed and scaling only the valence electron contribution. In this case the results of the solid model, although slightly less accurate, become very similar to those obtained with the free-atom model.

  16. Medium Energy Ion Scattering investigation of In diffusion in In2Se3/Bi2Se3

    NASA Astrophysics Data System (ADS)

    Lee, H. D.; Xu, C.; Shubeita, S.; Brahlek, M.; Koirala, N.; Oh, S.; Gustafsson, T.

    2013-03-01

    In2Se3, a band insulator, and Bi2Se3, a three-dimensional topological insulator, have inherently good chemical and structural compatibility. This suggests possible promising applications of In2Se3/Bi2Se3 devices as tunnel barriers and gate dielectrics. Recently, it has been shown that the similar (Bi1-xInx)2 Se3 thin system undergoes a transition from topological insulator to band insulator as a function of In concentration. It is therefore important to understand the extent of In diffusion in In2Se3/Bi2Se3 and its consequences for the transport properties. We have grown In2Se3/Bi2Se3 thin films on sapphire by Molecular Beam Epitaxy at three different temperatures. Medium Energy Ion Scattering measurements of those films showed that the higher growth temperature resulted in more In diffusion while our transport measurements showed that the Bi2Se3 mobility increases as the growth temperature decreases. We found that the trend of the mobility change of In2Se3/Bi2Se3 depending on the diffusion of In is similar with the trend of the mobility of (Bi1-xInx)2 Se3 as a function of In concentration.

  17. Medium Energy Ion Scattering Study of Oxygen Diffusion-Reactions in High-k Dielectrics on Si

    NASA Astrophysics Data System (ADS)

    Goncharova, Lyudmila; Bersuker, Gennadi

    2005-03-01

    Understanding the thermodynamics and kinetics of film growth during fabrication of high-κ gate stacks is vital to establish atomic level control of interfacial layers and to minimize defects. Annealing such films in different atmospheres may lead to diffusion and reactions with significant consequences on the electrical properties. We have used high-resolution medium energy ion scattering in combination with isotope tracing to investigate oxygen transport in model systems, including Hf and Ce oxides. The reaction of oxygen (pO2=10-2 Torr) with HfO2(SiO2)x/Si films at 500^oC was dominated by oxygen isotopic exchange (not SiO2 interfacial growth). The oxygen exchange rate decreases with an increase of SiO2 fraction in Hf silicate films and is almost fully suppressed (at 500^oC) for a (HfO2):(SiO2)=1:1 film composition. This reaction saturated with time and appeared to be enhanced after film recrystallization. Annealing in a nitrogen-containing atmosphere result in reduced O^18 incorporation and exchange. In comparison to Hf dielectrics, Ce silicates exhibit rapid interface growth upon oxygen exposure. Incorporating nitrogen into the structure lowers the rate of subsequent oxygen diffusion and incorporation.

  18. Differential cross sections for intermediate-energy electron scattering from α-tetrahydrofurfuryl alcohol: Excitation of electronic-states

    SciTech Connect

    Chiari, L.; Jones, D. B.; Thorn, P. A.; Pettifer, Z.; Duque, H. V.; Silva, G. B. da; Limão-Vieira, P.; Duflot, D.; Hubin-Franskin, M.-J.; Delwiche, J.; Blanco, F.; García, G.; and others

    2014-07-14

    We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20–50 eV, while the scattered electron was detected in the 10°–90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, “rotationally averaged” elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].

  19. Orientational dependence of the translational energy transfer in the scattering of oriented fluoroform and tert-butyl chloride molecules by a graphite(0001) surface

    NASA Astrophysics Data System (ADS)

    Ionov, Stanislav I.; LaVilla, Michael E.; Bernstein, Richard B.

    1990-11-01

    Time-of-flight distributions of beams of hexapole-oriented CHF3 and t-BuCl molecules scattered from a graphite (0001) surface have been measured for parallel vs antiparallel incident orientations of the molecular dipole with respect to the surface normal, over a range of surface temperatures 170≤Ts≤730 K. The observed difference in arrival times, Δtexp, for opposite initial orientations depends strongly on the degree of orientation of the incident molecules. In the analysis of the Δtexp data, we make use of the two-component model, which assumes that the scattered beams are composed of directly scattered and trapped/desorbed molecules. It is shown that in the common case of short residence times for the trapped molecules, the difference in arrival times for the directly scattered molecules, Δtdir, can be ascertained from the measured Δtexp. The magnitudes of the calculated Δtdir correspond to a strong orientation dependence in the translational energy transfer accompanying the direct scattering of CHF3 and t-BuCl by graphite (0001). The final translational energy of directly scattered molecules E' is found to be smaller for the collision of the H ``end'' of fluoroform with the graphite surface; for t-BuCl, E' is smaller for the Cl ``end'' collision. These are the orientations that also give rise to higher trapping probability. In the course of the present study, the residence times of t-BuCl on graphite (0001) have been measured over the surface temperature range 170

  20. Low-energy reactive ion scattering as a probe of surface femtochemical reaction: H+ and H- formation on ionic compound surfaces

    NASA Astrophysics Data System (ADS)

    Souda, R.; Suzuki, T.; Kawanowa, H.; Asari, E.

    1999-01-01

    Capture and loss of valence electrons during low-energy (50-500 eV) proton scattering from some alkali-halide surfaces such as LiCl, NaCl, and KF have been investigated in comparison with those from the TiO2(110) and Cs-adsorbed Si(100) surfaces. The primary H+ ion survives neutralization when scattered from the highly ionized target species existing on the surface. For H- ion formation, a close atomic encounter with individual target ions is found to be important; the H- ion is formed more efficiently on the cationic site than on the anionic site despite the fact that the valence electron is spacially localized on the latter. This is because the charge state of scattered hydrogen is determined during a transient chemisorption state and amphoteric hydrogen tends to be coordinated negatively (positively) on the cationic site (the anionic site). The final charge state of scattered hydrogen is fixed at a certain bond-breaking distance (˜5.0 a.u.) from the surface where the well-defined atomic orbital of hydrogen evolves. The competing nonlocal resonance tunneling is suppressed at the ionic-compound surfaces due to the existence of a large band gap, so that hydrogen is scattered without losing the memory of such a transient chemisorption state.

  1. Low-energy elastic and inelastic scattering of electrons from SO2 using the R -matrix method

    NASA Astrophysics Data System (ADS)

    Gupta, Monika; Baluja, K. L.

    2006-04-01

    R -matrix method is used to calculate elastic differential, integral, and momentum transfer cross sections for electron- SO2 collision. The electron-impact excitation cross sections for first seven low-lying electronic excited states of SO2 molecule from the ground state of SO2 molecule have been calculated for the first time. Sixteen low-lying electronic states of SO2 molecule are included in the close coupling expansion of the wave function of the entire scattering system, which have vertical excitation energies up to 10.51eV . Configuration-interaction (CI) wave functions are used to calculate these excitation energies. In our CI model, we keep the core 14 electrons frozen in doubly occupied molecular orbitals 1a1 , 2a1 , 3a1 , 4a1 , 1b1 , 1b2 , 2b2 and the remaining 18 electrons span the relevant active space: 5a1 , 6a1 , 7a1 , 8a1 , 9a1 , 2b1 , 3b1 , 3b2 , 4b2 , 5b2 , 6b2 , and 1a2 . Our calculated dipole moment of the ground state of SO2 at its equilibrium geometry is 0.79a.u. , which is in reasonable agreement with the corresponding experimental value 0.64a.u. Our calculations detect one bound SO2- state (B12) at the equilibrium geometry of SO2 molecule. Both shape as well as core-excited shape resonances have been identified in the present work and are correlated with the experimental results on dissociative electron attachment study. A detailed analysis of resonances is provided. Cross sections are reported for the electron impact energy range 0-15eV . All cross section calculations are performed in the fixed-nuclei approximation at the experimental equilibrium geometry of the ground state of SO2 molecule. We have also investigated dependence of resonances on the geometry of SO2 molecule to probe the possible pathways for dissociation of resulting negative ion upon electron attachment. We have excellent agreement of differential, elastic integral, and momentum transfer cross sections calculated in the 16-state R -matrix approximation with the available

  2. Q2 dependence of the average squared transverse energy of jets in deep-inelastic muon-nucleon scattering with comparison to perturbative QCD predictions

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Arndotïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1994-01-01

    The average squared transverse energy of jets in deep-inelastic muon-nucleon scattering is measured as a function of the momentum transfer squared (Q2), in the range 3energy will depend upon the strong coupling constant (αS). Identifying the transverse energy of the jets with those of the corresponding partons, αS is found to vary with Q2 as predicted by QCD.

  3. Identifying regions of strong scattering at the core-mantle boundary from analysis of PKKP precursor energy

    USGS Publications Warehouse

    Rost, S.; Earle, P.S.

    2010-01-01

    We detect seismic scattering from the core-mantle boundary related to the phase PKKP (PK. KP) in data from small aperture seismic arrays in India and Canada. The detection of these scattered waves in data from small aperture arrays is new and allows a better characterization of the fine-scale structure of the deep Earth especially in the southern hemisphere. Their slowness vector is determined from array processing allowing location of the heterogeneities at the core-mantle boundary using back-projection techniques through 1D Earth models. We identify strong scattering at the core-mantle boundary (CMB) beneath the Caribbean, Patagonia and the Antarctic Peninsula as well as beneath southern Africa. An analysis of the scattering regions relative to sources and receivers indicates that these regions represent areas of increased scattering likely due to increased heterogeneities close to the CMB. The 1. Hz array data used in this study is most sensitive to heterogeneity with scale lengths of about 10. km. Given the small size of the scatterers, a chemical origin of the heterogeneities is likely. By comparing the location of the fine-scale heterogeneity to geodynamical models and tomographic images, we identify different scattering mechanisms in regions related to subduction (Caribbean and Patagonia) and dense thermo chemical piles (Southern Africa). ?? 2010 Elsevier B.V.

  4. Electron Neutrino Appearance in the MINOS Experiment

    SciTech Connect

    Holin, Anna Maria

    2010-02-01

    The MINOS experiment is a long-baseline neutrino oscillation experiment which sends a high intensity muon neutrino beam through two functionally identical detectors, a Near detector at the Fermi National Accelerator Laboratory in Illinois, 1km from the beam source, and a Far detector, 734km away, in the Soudan Mine in Minnesota. MINOS may be able to measure the neutrino mixing angle parameter sin213 for the rst time. Detector granularity, however, makes it very hard to distinguish any e appearance signal events characteristic of a non-zero value of θ 13 from background neutral current (NC) and short-track vμ charged current (CC) events. Also, uncertainties in the hadronic shower modeling in the kinematic region characteristic of this analysis are relatively large. A new data-driven background decomposition method designed to address those issues is developed and its results presented. By removing the long muon tracks from vμ-CC events, the Muon Removed Charge Current (MRCC) method creates independent pseudo-NC samples that can be used to correct the MINOS Monte Carlo to agree with the high-statistics Near detector data and to decompose the latter into components so as to predict the expected Far detector background. The MRCC method also provides an important cross-check in the Far detector to test the background in the signal selected region. MINOS finds a 1.0-1.5 σ ve-CC excess above background in the Far detector data, depending on method used, for a total exposure of 3.14 x 1020 protons-on-target. Interpreting this excess as signal, MINOS can set limits on sin213. Using the MRCC method, MINOS sets a limit of sin2 2 θ 13 < 0.265 at the 90% confidence limit for a CP-violating phase δ = 0.

  5. Search for Electron Neutrino Appearance in MINOS

    SciTech Connect

    Orchanian, Mhair; /Caltech

    2011-09-01

    The MINOS Collaboration continues its search for {nu}{sub e} appearance in the NuMI (Neutrinos at the Main Injector) beam at Fermilab. Neutrinos in the beam interact in the Near Detector, located 1 km from the beam source, allowing us to characterize the backgrounds present in our analysis. In particular, we can estimate the number of {nu}{sub e} candidate events we expect to see in the Far Detector (735 km away, in the Soudan mine in northern Minnesota) in the presence or absence of {nu}{sub {mu}} {yields} {nu}{sub e} oscillation. Recent efforts to improve the sensitivity of the analysis, including upgrades to the event identification algorithm and fitting procedure, are discussed, and the latest results from the search are presented.

  6. Electron Neutrino Appearance in the MINOS Experiment

    SciTech Connect

    Orchanian, Mhair-armen Hagop

    2012-01-01

    This thesis describes a search for ve appearance in the two-detector long-baseline MINOS neutrino experiment at Fermilab, based on a data set representing an exposure of 8.2×1020 protons on the NuMI target. The analysis detailed herein represents an increase in sensitivity to the θ13 mixing angle of approximately 25% over previous analyses, due to improvements in the event discriminant and fitting technique. Based on our observation, we constrain the value of θ13 further, finding 2 sin2θ 23 sin2θ 13< 0.12(0.20) at the 90% confidence level for δCP = 0 and the normal (inverted) neutrino mass hierarchy. The best-fit value is 2 sin2θ 23 sin2θ 13 = 0.041+0.047 -0.031(0.079+0.071 -0.053) under the same assumptions. We exclude the θ 13 = 0 hypothesis at the 89% confidence level.

  7. A new measurement of the energy dependence of nuclear transparency for large momentum transfer 12C(p,2p) scattering

    NASA Astrophysics Data System (ADS)

    Leksanov, A.; Alster, J.; Asryan, G.; Averichev, Y.; Barton, D.; Baturin, V.; Bukhtojarova, N.; Carroll, A.; Schetkovsky, A.; Heppelmann, S.; Kawabata, T.; Malki, A.; Makdisi, Y.; Minina, E.; Navon, I.; Nicholson, H.; Ogawa, A.; Panebratsev, Y.; Piasetzky, E.; Shimanskiy, S.; Tang, A.; Watson, J. W.; Yoshida, H.; Zhalov, D.

    2000-12-01

    We present a new measurement of the energy dependence of nuclear transparency from AGS experiment E850, performed using the EVA solenoidal spectrometer, upgraded since 1995. Using a secondary beam from the AGS accelerator, we simultaneously measured pp elastic scattering from hydrogen and (p,2p) quasi-elastic scattering in carbon at incoming momenta of 5.9, 8.0, 9.0, 11.7 and 14.4 GeV/c. This incident momentum range corresponds to a Q2 region between 4.8 and 12.7 (GeV/c)2. The detector allowed us to do a complete kinematic analysis for the center-of-mass polar angles in the range 85°-90°. We report on the measured variation of the nuclear transparency with energy and compare the new results with previous measurements.

  8. Study of Scattering 1H, 12C and 16O Nuclei on 1P-SHELL at Energy Near the Coulomb Barrier

    NASA Astrophysics Data System (ADS)

    Amar, A.; Hamada, S.; Burtebayev, N.; Amangeldy, N.

    Differential cross sections for the 6,7Li(p,p)6,7Li and 10,11B(p,p)10,11B elastic scattering were measured over the proton laboratory energy range from 300 to 1050 keV. The transfer reaction of the elastic scattering of carbon and oxygen on oxygen and carbon nuclei was studied through different experiments with incident beam of energy 1.75 MeV/ nucleon. Depending on the measured data by us and literature data, we could enhance the potential parameters using ECIS88 Code, as well as SPI-GENOA Code. Good agreement between theoretical and experimental in whole range.

  9. Low-energy positron scattering from gas-phase tetrahydrofuran: A quantum treatment of the dynamics and a comparison with experiments

    SciTech Connect

    Franz, J.; Gianturco, F. A.

    2013-11-28

    In this paper we report new quantum calculations of the dynamics for low-energy positrons interacting with gaseous molecules of tetrahydrofuran. The new quantum scattering cross sections are differential and integral cross sections at collision energies between 1.0 and 25.0 eV and include a careful treatment of the additional effects on the scattering process brought about by the permanent dipole moment of the target molecule. The present results are compared with an extensive range of measured data, both for the angular distributions and for the elastic integral cross sections and agree remarkably well with all findings. The new calculated quantities reported here also show the importance of correcting the experimental integral cross sections for the angular discrimination in the forward direction.

  10. Determination of {sup 16}O and {sup 18}O sensitivity factors and charge-exchange processes in low-energy ion scattering

    SciTech Connect

    Tellez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Kilner, J. A.; Brongersma, H. H.

    2012-10-08

    Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He{sup +} scattered by {sup 18}O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for E{sub i} < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for E{sub i} > 2 keV. The ion fractions P{sup +} were determined for Si and O using the characteristic velocity method to quantify the surface density. The {sup 18}O/{sup 16}O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

  11. Angular and charge state distributions of highly charged ions scattered during low energy surface-channeling interactions with Au(110)

    SciTech Connect

    Meyer, F.W.; Folkerts, L.; Schippers, S.

    1994-10-01

    The authors have measured scattered projectile angular and charge state distributions for 3.75 keV/amu O{sup q+} (3 {le} q {le} 8) and 1.2 keV/amu Ar{sup 1+} (3 {le} q {le} 14) ions grazingly incident along the [110] and [100] directions of a Au(110) single crystal target. Scattered projectile angular distribution characteristic of surface channeling are observed. For both incident species, the dominant scattered charge fraction is neutral, which varies only by a few percent as a function of incident charge state. Significant O{sup {minus}} formation is observed, which manifests a distinct velocity threshold. For incident Ar projectiles with open L-shells, the positive scattered charge fractions, while always less than about 10%, increase linearly with increasing number of initial L-shell vacancies.

  12. Probing ultrathin film continuity and interface abruptness with x-ray photoelectron spectroscopy and low-energy ion scattering

    SciTech Connect

    Zhang, Wenyu; Nahm, Rambert K.; Engstrom, James R.; Ma, Paul F.

    2013-11-15

    The authors have examined ultrathin (≤10 Å) tantalum nitride (TaN{sub x}) thin films deposited by atomic layer deposition (ALD) on three surfaces relevant to interconnect layers in microelectronic devices: thermally grown SiO{sub 2}; a Cu thin film grown by physical vapor deposition, and a carbon-doped SiO{sub 2} porous low-κ thin film. The authors have employed ex situ angle-resolved x-ray photoelectron spectroscopy (ARXPS), low-energy ion scattering spectroscopy (LEISS), and atomic force microscopy (AFM) to determine the continuity of these thin films, and by implication, the abruptness of the thin film/substrate interface. On SiO{sub 2} and low-κ, the authors find similar results: both ARXPS and AFM indicate that smooth, uniform thin films are deposited, consistent with nearly layer-by-layer growth of TaN{sub x} on these surfaces. Examination of these films using LEISS reveals that while the 10 Å TaN{sub x} thin films are continuous, the 5 Å TaN{sub x} thin films are not continuous and may possess on the order of ∼10% exposed substrate in the form of small subnanometer inclusions. On Cu, the situation is quite different. The TaN{sub x} thin films on these surfaces are not continuous, and our results point to a mixed layer of TaN{sub x} and Cu forming during ALD. In all cases, if one were to rely solely on results from ARXPS, the picture would be incomplete as the results from LEISS are ultimately decisive concerning thin film continuity.

  13. From QCD-based hard-scattering to nonextensive statistical mechanical descriptions of transverse momentum spectra in high-energy p p and p p ¯ collisions

    NASA Astrophysics Data System (ADS)

    Wong, Cheuk-Yin; Wilk, Grzegorz; Cirto, Leonardo J. L.; Tsallis, Constantino

    2015-06-01

    Transverse spectra of both jets and hadrons obtained in high-energy p p and p p ¯ collisions at central rapidity exhibit power-law behavior of 1 /pTn at high pT . The power index n is 4-5 for jet production and is 6-10 for hadron production. Furthermore, the hadron spectra spanning over 14 orders of magnitude down to the lowest pT region in p p collisions at the LHC can be adequately described by a single nonextensive statistical mechanical distribution that is widely used in other branches of science. This suggests indirectly the possible dominance of the hard-scattering process over essentially the whole pT region at central rapidity in high-energy p p and p p ¯ collisions. We show here direct evidences of such a dominance of the hard-scattering process by investigating the power indices of UA1 and ATLAS jet spectra over an extended pT region and the two-particle correlation data of the STAR and PHENIX collaborations in high-energy p p and p p ¯ collisions at central rapidity. We then study how the showering of the hard-scattering product partons alters the power index of the hadron spectra and leads to a hadron distribution that may be cast into a single-particle nonextensive statistical mechanical distribution. Because of such a connection, the nonextensive statistical mechanical distribution may be considered as a lowest-order approximation of the hard-scattering of partons followed by the subsequent process of parton showering that turns the jets into hadrons, in high-energy p p and p p ¯ collisions.

  14. Experimental verification of a method to create a variable energy neutron beam from a monoenergetic, isotropic source using neutron elastic scatter and time of flight

    NASA Astrophysics Data System (ADS)

    Whetstone, Zachary D.; Flaska, Marek; Kearfott, Kimberlee J.

    2016-08-01

    An experiment was performed to determine the neutron energy of near-monoergetic deuterium-deuterium (D-D) neutrons that elastically scatter in a hydrogenous target. The experiment used two liquid scintillators to perform time of flight (TOF) measurements to determine neutron energy, with the start detector also serving as the scatter target. The stop detector was placed 1.0 m away and at scatter angles of π/6, π/4, and π/3 rad, and 1.5 m at a scatter angle of π/4 rad. When discrete 1 ns increments were implemented, the TOF peaks had estimated errors between -21.2 and 3.6% relative to their expected locations. Full widths at half-maximum (FWHM) ranged between 9.6 and 20.9 ns, or approximately 0.56-0.66 MeV. Monte Carlo simulations were also conducted that approximated the experimental setup and had both D-D and deuterium-tritium (DT) neutrons. The simulated results had errors between -17.2 and 0.0% relative to their expected TOF peaks when 1 ns increments were applied. The largest D-D and D-T FWHMs were 26.7 and 13.7 ns, or approximately 0.85 and 4.98 MeV, respectively. These values, however, can be reduced through manipulation of the dimensions of the system components. The results encourage further study of the neutron elastic scatter TOF system with particular interest in application to active neutron interrogation to search for conventional explosives.

  15. Low-energy tail of the giant dipole resonance in Mo98 and Mo100 deduced from photon-scattering experiments

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Schwengner, R.; Dönau, F.; Erhard, M.; Grosse, E.; Junghans, A. R.; Kosev, K.; Schilling, K. D.; Wagner, A.; Bečvář, F.; Krtička, M.

    2008-06-01

    Dipole-strength distributions in the nuclides Mo98 and Mo100 up to the neutron-separation energies have been studied in photon-scattering experiments at the bremsstrahlung facility of the Forschungszentrum Dresden-Rossendorf. To determine the dipole-strength distributions up to the neutron-emission thresholds, statistical methods were developed for the analysis of the measured spectra. The measured spectra of scattered photons were corrected for detector response and atomic background by simulations using the code GEANT3. Simulations of γ-ray cascades were performed to correct the intensities of the transitions to the ground state for feeding from higher-lying levels and to determine their branching ratios. The photoabsorption cross sections obtained for Mo98 and Mo100 from the present (γ,γ') experiments are combined with (γ,n) data from literature, resulting in a photoabsorption cross section covering the range from 4 to about 15 MeV of interest for network calculations in nuclear astrophysics. Novel information about the low-energy tail of the giant dipole resonance and its energy dependence is derived. The photoabsorption cross sections deduced from the present photon-scattering experiments are compared with existing data from neutron capture and He3-induced reactions.

  16. Net electron-phonon scattering rates in InN/GaN multiple quantum wells: The effects of an energy dependent acoustic deformation potential

    SciTech Connect

    Xia, H. Patterson, R.; Feng, Y.; Shrestha, S.; Conibeer, G.

    2014-08-11

    The rates of charge carrier relaxation by phonon emission are of substantial importance in the field of hot carrier solar cell, primarily in investigation of mechanisms to slow down hot carrier cooling. In this work, energy and momentum resolved deformation potentials relevant to electron-phonon scattering are computed for wurtzite InN and GaN as well as an InN/GaN multiple quantum well (MQW) superlattice using ab-initio methods. These deformation potentials reveal important features such as discontinuities across the electronic bandgap of the materials and variations over tens of eV. The energy dependence of the deformation potential is found to be very similar for wurtzite nitrides despite differences between the In and Ga pseudopotentials and their corresponding electronic band structures. Charge carrier relaxation by this mechanism is expected to be minimal for electrons within a few eV of the conduction band edge. However, hole scattering at energies more accessible to excitation by solar radiation is possible between heavy and light hole states. Moderate reductions in overall scattering rates are observed in MQW relative to the bulk nitride materials.

  17. On a partial differential equation method for determining the free energies and coexisting phase compositions of ternary mixtures from light scattering data.

    PubMed

    Ross, David S; Thurston, George M; Lutzer, Carl V

    2008-08-14

    In this paper we present a method for determining the free energies of ternary mixtures from light scattering data. We use an approximation that is appropriate for liquid mixtures, which we formulate as a second-order nonlinear partial differential equation. This partial differential equation (PDE) relates the Hessian of the intensive free energy to the efficiency of light scattering in the forward direction. This basic equation applies in regions of the phase diagram in which the mixtures are thermodynamically stable. In regions in which the mixtures are unstable or metastable, the appropriate PDE is the nonlinear equation for the convex hull. We formulate this equation along with continuity conditions for the transition between the two equations at cloud point loci. We show how to discretize this problem to obtain a finite-difference approximation to it, and we present an iterative method for solving the discretized problem. We present the results of calculations that were done with a computer program that implements our method. These calculations show that our method is capable of reconstructing test free energy functions from simulated light scattering data. If the cloud point loci are known, the method also finds the tie lines and tie triangles that describe thermodynamic equilibrium between two or among three liquid phases. A robust method for solving this PDE problem, such as the one presented here, can be a basis for optical, noninvasive means of characterizing the thermodynamics of multicomponent mixtures. PMID:18715050

  18. Net electron-phonon scattering rates in InN/GaN multiple quantum wells: The effects of an energy dependent acoustic deformation potential

    NASA Astrophysics Data System (ADS)

    Xia, H.; Patterson, R.; Feng, Y.; Shrestha, S.; Conibeer, G.

    2014-08-01

    The rates of charge carrier relaxation by phonon emission are of substantial importance in the field of hot carrier solar cell, primarily in investigation of mechanisms to slow down hot carrier cooling. In this work, energy and momentum resolved deformation potentials relevant to electron-phonon scattering are computed for wurtzite InN and GaN as well as an InN/GaN multiple quantum well (MQW) superlattice using ab-initio methods. These deformation potentials reveal important features such as discontinuities across the electronic bandgap of the materials and variations over tens of eV. The energy dependence of the deformation potential is found to be very similar for wurtzite nitrides despite differences between the In and Ga pseudopotentials and their corresponding electronic band structures. Charge carrier relaxation by this mechanism is expected to be minimal for electrons within a few eV of the conduction band edge. However, hole scattering at energies more accessible to excitation by solar radiation is possible between heavy and light hole states. Moderate reductions in overall scattering rates are observed in MQW relative to the bulk nitride materials.

  19. Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

    SciTech Connect

    Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael; Abril, Isabel; Kostarelos, Kostas

    2011-09-01

    The effect of bulk and surface excitations to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes (MWNTs) is studied using the dielectric formalism. Calculations are based on a semiempirical dielectric response function for MWCNTs determined by means of a many-pole plasmon model with parameters adjusted to available experimental spectroscopic data under theoretical sum-rule constrains. Finite-size effects are considered in the context of electron gas theory via a boundary correction term in the plasmon dispersion relations, thus, allowing a more realistic extrapolation of the electronic excitation spectrum over the whole energy-momentum plane. Energy-loss differential and total inelastic scattering cross sections as a function of electron energy and distance from the surface, valid over the energy range {approx}50-30,000 eV, are calculated with the individual contribution of bulk and surface excitations separated and analyzed for the case of normally incident and escaping electrons. The sensitivity of the results to the various approximations for the spatial dispersion of the electronic excitations is quantified. Surface excitations are shown to have a strong influence upon the shape and intensity of the energy-loss differential cross section in the near surface region whereas the general notion of a spatially invariant inelastic mean free path inside the material is found to be of good approximation.

  20. High-energy-resolution monochromator for nuclear resonant scattering of synchrotron radiation by Te-125 at 35.49 keV

    NASA Astrophysics Data System (ADS)

    Imai, Yasuhiko; Yoda, Yoshitaka; Kitao, Shinji; Masuda, Ryo; Higashitaniguchi, Satoshi; Inaba, Chika; Seto, Makoto

    2007-09-01

    We have developed a high-resolution monochromator (HRM) for the measurement of nuclear resonant scattering (NRS) of synchrotron radiation by Te-125 at 35.49 keV using the backscattering of sapphire (9 1 -10 68). HRMs for nuclei with excitation energies less than 30 keV have been successfully developed using high angle diffractions by silicon crystals. Nearly perfect silicon crystal, however, is not suitable for high efficient HRMs at higher energy regions because the symmetry of the crystal structure is high and the Debye-temperature is low. Therefore, we used high quality synthetic sapphire crystal, which has low symmetry of crystal structure and high Debye-temperature. The temperature of the crystal was precisely controlled around 218 K to diffract synchrotron radiation with a Bragg angle of π/2 - 0.52 mrad. Energy was tuned by changing the crystal temperature under the condition of constant diffraction angle. Energy resolution was measured by detecting nuclear forward scattering by Te-125 in enriched TeO II. The relative energy resolution of 2.1×10 -7 is achieved, that is 7.5 meV in energy bandwidth. This HRM opens studies on element-specific dynamics and electronic state of substances containing Te-125.