Dissertations / Theses: '(*ELECTRONS, ELASTIC SCATTERING)'

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Greenwood, Jason B. "Elastic and inelastic scattering of electrons from ions." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282155.

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Went, Michael Ray, and n/a. "Scattering of Spin Polarized Electrons from Heavy Atoms: Krypton and Rubidium." Griffith University. School of Science, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040220.134142.

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This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.

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Moffit, Bryan James. "Elastic scattering of longitudinally polarized electrons from helium-4: A measurement of G(E)(S) at Q2 = 0.1 (GeV/c)2." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539623515.

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We have performed the first measurement of the parity-violating asymmetry in the elastic scattering of longitudinally polarized electrons from 4He. The kinematics chosen (Q 2 = 0.1 (GeV/c)2) provide a direct sensitivity to the strange electric form factor GsE with negligible contributions from competing effects. This experiment was performed in June 2004 and July-September 2005 in Hall A at Jefferson Lab. This work represents the experimental setup and analysis of the 2004 dataset.;The final statistical precision, from the combined datasets, put stringent requirements on the systematic errors that normalize the asymmetry (e.g. Q2, beam polarization, backgrounds). The experimental and analysis techniques, presented in this thesis, resulted in a 12.9% relative measure of the parity-violating asymmetry for the 2004 dataset, and a 4.1% relative measure for the 2005 dataset (the most precise measurement of a parity-violating asymmetry ever obtained).;The 2004 measured result, APV = 6.72 +/- 0.84 (stat) +/- 0.21 (syst) ppm, allows for the extraction of the electric strange form factor: GsE (Q2 = 0.1) = -0.038 +/- 0.042 (stat) +/- 0.010 (syst). When combined with results from previous experiments, at nearly the same kinematics, a clear picture of the contribution of strange quarks to the nucleon's electric and magnetic form factors emerges.

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Gedik, Nuh. "Recombination and propagation of quasiparticles in cuprate superconductors." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/842568-Q1sG4c/native/.

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doctoral thesis, Ph.D, University of California, Berkeley, Berkeley, CA.
Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55855" Gedik, Nuh. USDOE Director. Office of Science. Office of Basic Energy Sciences 05/20/2004. Report is also available in paper and microfiche from NTIS.

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Moreno, Carrascosa Andrés. "Theory of elastic and inelastic X-ray scattering." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31442.

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X-rays have been widely exploited to unravel the structure of matter since their discovery in 1895. Nowadays, with the emergence of new X-ray sources with higher intensity and very short pulse duration, notably X-ray Free Electron Lasers, the number of experiments that may be considered in the X-ray regime has increased dramatically, making the characterization of gas phase atoms and molecules in space and time possible. This thesis explores in the theoretical analysis and calculation of X-ray scattering atoms and molecules, far beyond the independent atom model. Amethod to calculate inelastic X-ray scattering from atoms and molecules is presented. The method utilizes electronic wavefunctions calculated using ab-initio electronic structure methods. Wavefunctions expressed in Gaussian type orbitals allow for efficient calculations based on analytical Fourier transforms of the electron density and overlap integrals. The method is validated by extensive calculations of inelastic cross-sections in H, He+, He, Ne, C, Na and N2. The calculated cross-sections are compared to cross-sections from inelastic X-ray scattering experiments, electron energy-loss spectroscopy, and theoretical reference values. We then begin to account for the effect of nuclear motion, in the first instance by predicting elastic X-ray scattering from state-selected molecules. We find strong signatures corresponding to the specific vibrational and rotational state of (polyatomic) molecules. The ultimate goal of this thesis is to study atomic and molecular wavepackets using time-resolved X-ray scattering. We present a theoretical framework based on quantum electrodynamics and explore various elastic and inelastic limits of the scattering expressions. We then explore X-ray scattering from electronic wavepackets, following on from work by other groups, and finally examine the time-resolved X-ray scattering from non-adiabatic electronic-nuclear wavepackets in the H2 molecule, demonstrating the importance of accounting for the inelastic effects.

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Holbrook, Owen. "Simulation of energy filtered electron microscopy." Thesis, University of Bath, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266475.

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Rvachev, Marat. "Study of the Quasielastic {sup 3}He(e,e{prime}p) Reaction at Q{sup 2}=1.5 (GeV/c){sup 2} up to Missing Momenta of 1 GeV/c." Washington, D.C : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Energy Research ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/824894-w3sMWi/native/.

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Thesis (Ph.D.); Submitted to Massachusetts Inst. of Tech., Cambridge, MA (US); 1 Sep 2003.
Published through the Information Bridge: DOE Scientific and Technical Information. "JLAB-PHY-03-167" "DOE/ER/40150-2745" Marat Rvachev. 09/01/2003. Report is also available in paper and microfiche from NTIS.

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Huang, Yunfei. "Front-form calculations of exchange currents in elastic electron-deuteron scattering." Diss., University of Iowa, 2008. https://ir.uiowa.edu/etd/217.

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Electron-deuteron scattering is an ideal tool for studying nuclear structure and nuclear forces. The elastic deuteron current matrix elements have been calculated using a Poincaré invariant quantum model with a light-front kinematic symmetry. The impulse approximation violates the Poincarécovariance and current conservation for the interacting system and two-body currents are required to satisfy these constraints. A model two-body current that has a structure motivated by "pair'' currents was constructed in this work. It appears naturally in quantum field theory. The Argonne V18 potential was used as the model nucleon-nucleon interaction and empirical nucleon form factors were used as input in the calculation of the deuteron form factors and structure functions. The sensitivity of the results to different nucleon-nucleon interactions, different nucleon form factors, and different choices of independent current matrix elements was examined. The calculations of elastic electron-deuteron scattering observables in this work are consistent with experiment to within uncertainties in the input.

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Butuceanu, Cornel. "Quasi-elastic electron scattering from a high-momentum nucleon in deuterium." W&M ScholarWorks, 2005. https://scholarworks.wm.edu/etd/1539623479.

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We present an analysis of data from experiment E94-019 using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (TJNAF). The experiment ran in the spring of 2002 over the course of two months with 5.765 GeV unpolarized electron beam on a liquid deuterium target and collected a total of 4.5 x 109 triggers. These data cover a wide kinematic range from the quasi-elastic peak up to an invariant mass W ≈ 3 GeV of the final hadronic system for momentum transfer Q 2 from 1.5 to 6.0 GeV2. Using CLAS we tagged spectator protons released in quasielastic scattering from high-momentum neutrons in deuterium at large emission angles with respect to the momentum transfer direction. Using these data one can test the physics of small-sized wavepacket expansion inside the nucleus. The absorption of a high-momentum virtual photon on a nucleon leads to the production of a small-sized wavepacket (due to the suppression of long-range pion and gluon fields) which evolves rapidly in time until it reaches the nucleon size. We can investigate how such a wavepacket moves within a nucleus and how long-range fields are restored. This study could provide information about the quark-gluon degrees of freedom, internucleon forces in nuclei, and color coherence effects such as color screening (CS) and color transparency (CT). Color screening would allow a small-sized object to escape from the nucleus without further interaction. Measuring the evolution of FSIs with the momentum transfer Q2 could reveal whether or not nuclear transparency may occur in quasielastic reactions such as d(e,e'p)n. We computed the ratio of the experimental cross section for d(e,e'p)n measured for kinematics dominated by rescattering effects to the cross section measured for the kinematics dominated by screening effects (suppression of FSIs). We have extracted absolute cross sections for the inclusive d(e,e') channel. They are presented in two-dimension kinematic bins with Q2 = 1.7 - 6.7 GeV2 and x = 0.7--1.9. By mapping these cross sections we can extract the probabilities of finding short range nucleon-nucleon correlation (SRC) state in nucleus. Absolute cross section for the exclusive d(e,e'p)n channel are presented for spectator momenta ps from 250 to 1000 MeV/c and Q2 = 2--6 GeV 2. Experimental measurements suggest a strong contribution from meson exchange and Delta-isobar currents which dominate FSIs. This makes it difficult to observe color coherent effects. This picture is corroborated by new theoretical developments.

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Kula, Mathias. "Elastic and Inelastic Electron Tunneling in Molecular Devices." Licentiate thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3958.

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Schmidt, Axel (Axel William). "Measuring the lepton sign asymmetry in elastic electron-proton scattering with OLYMPUS." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107040.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 265-273).
OLYMPUS is a particle physics experiment that collected data in 2012 at DESY, in Hamburg, Germany, on the asymmetry between positron-proton and electron-proton elastic scattering cross sections. A non-zero asymmetry is evidence of hard two-photon exchange, which has been hypothesized to cause the discrepancy in measurements of the proton's electromagnetic form factors. Alternating electron and positron beams, accelerated to 2 GeV, were directed through a windowless, gaseous, hydrogen target, and the scattered lepton and recoiling proton were detected in coincidence using a large acceptance magnetic spectrometer. Determining the relative integrated luminosity between the electron and positron data sets was critical, and a new technique, involving multi-interaction events, was developed to achieve the desired sub-percent accuracy. A detailed Monte Carlo simulation was built in order to reproduce the convolution of systematic effects at every stage of the experiment. The first stage in the simulation was new radiative event generator, which permitted the full simulation of the non-trivial radiative corrections to the measurement. The analysis of the data and simulation showed that the lepton sign asymmetry rises by several percent between a momentum transfer of 0.5 GeV2 /c2 and 2.25 GeV2 /c2 . This rise as a function of increasing momentum transfer confirms that two photon exchange at least partially contributes to the proton form factor discrepancy.
by Axel Schmidt.
Ph. D.

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Zhang, Chi Ph D. Massachusetts Institute of Technology. "Measurement of tensor analyzing powers in elastic electron deuteron scattering with BLAST." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/40030.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.
Includes bibliographical references (p. 219-225).
This work reports a precision measurement of deuteron tensor analyzing powers T20 and T21 at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range of 2:15 to 4:5 fm¡1 in the Bates Large Acceptance Spectrometer Toroid (BLAST) with a highly polarized internal gas target. Deuterium form factors GC and GQ were separated using the new data with better precision and the location of the first node of the deuteron monopole form factor was confirmed. The new data provide strong constraints on the nuclear models in a momentum transfer range covering the minima of T20 and the first node of GC.
by Chi Zhang.
Ph.D.

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Alahmade, Walaa M. "ANALYTICAL AND MONTE CARLO CALCULATIONS FOR ELASTIC ELECTRON-TRITON SCATTERING AT JEFFERSON LABORATORY." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1429465640.

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14

Mahgerefteh, Massoud. "Absolute elastic e -He and total electronically elastic e -H scattering cross-section measurements from 1-19 eV /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1985.

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Russell, Rebecca Lynn. "A measurement of the two-photon exchange effect in elastic electron-proton scattering with OLYMPUS." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107042.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 185-190).
Elastic electron-proton scattering has long been the tool of choice for the study of the proton form factors, GE(Q 2 ) and GM(Q2 ), which describe the electric and magnetic distributions of the proton as a function of momentum transfer. Recent experiments, measuring the form factors from polarization observables in polarized elastic electron-proton scattering, have found values of the ratio GE(Q2 )/GM(Q2) at high Q2 that contradict the results from unpolarized measurements. A proposed explanation for this discrepancy is the unaccounted two-photon exchange radiative correction, which could affect the unpolarized measurements. As this effect is currently not possible to calculate in a model-independent way, the OLYMPUS experiment was designed to make a direct measurement of it by measuring the elastic positron-proton to electron-proton scattering cross section ratio. The experiment was run in 2012 at DESY using the BLAST spectrometer and the DORIS positron and electron beams at 2 GeV incident on a gaseous hydrogen target. To analyze the data, a careful reconstruction of the scattering events, detailed simulation of the experimental setup, and full radiative corrections to the measured cross sections were performed. Preliminary results for the experiment show a statistically significant two-photon exchange effect, increasing over the measurement range of 0.6 GeV2 < Q2 < 2.35 GeV2 . These preliminary results suggest that two-photon exchange could explain the GE(Q2)/Gm(Q2 ) puzzle.
by Rebecca Lynn Russell.
Ph. D.

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Lee, Zhongbo [Verfasser]. "Incorporate elastic and inelastic scattering into image calculation for low-voltage transmission electron microscope / Zhongbo Lee." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2014. http://d-nb.info/1049987411/34.

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Ward, Sandra June. "A theoretical study of elastic electron positronium scattering and photo-absorption by the positronium negative ion." Thesis, Royal Holloway, University of London, 1986. http://repository.royalholloway.ac.uk/items/53f1d29a-c94b-4133-9934-40fa3189c6d6/1/.

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This thesis describes both a theoretical study of low-energy electron scattering by positronium (Ps), below the n=2 threshold and the photo detachment of the positronium negative ion (Ps-.) E+/- + Ps(1s) → e+/- + Ps(1s) Ps- + hv → Ps(1s) + e- The importance of the photodetachment of Ps- was recognized by Mills (in 1981) since it can be used as a possible mechanism of producing a slow monoenergetic Ps beam. Accurate 1,3S and 1,3P phase shifts were evaluated by the Kohn and inverse Kohn variational methods in which very flexible trial functions were used. Higher order phase shifts were determined by the static exchange and adiabatic ex-change models in order to obtain the total elastic, momentum-transfer, ortho-para conversion and elastic differential cross sections for the scattering process. In the variational calculation, the lowest 1S, 1P and the two lowest 3P resonances, which lie just below the n=2 threshold were revealed. The scattering results for ea-Ps were compared with those for ea-H. Using a variational bound-state wave function, which contained 95 linear and 2 non-linear parameters, and a p-wave continuum function, which contained 220-linear and 3 non-linear parameters, the photo detachment cross section was calculated in both the length and velocity formulation. The agreement between the length and velocity forms was to better than 1.6% for lambda 27.5 x 10³A, and the sum-rule was satisfied to within 2%. By systematically improving both the bound-state and continuum wave functions separately, the reliability of the cross section was determined. A comparison of the photo detachment of Ps- was made with the corresponding atomic ion, H-.

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Kabir, Al Amin. "DETERMINATION OF THE CHARGE RADII OF SEVERAL LIGHT NUCLEI FROM PRECISION, HIGH-ENERGY ELECTRON ELASTIC SCATTERING." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1448878891.

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Caia, George Laurentiu. "Pion Photo- and Electro-production from the Nucleon." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1097607602.

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Bartlett, Kurtis David. "First Measurements of the Parity-Violating and Beam-Normal Single-Spin Asymmetries in Elastic Electron-Aluminum Scattering." W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1550153799.

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The Qweak collaboration has made the first measurements of the elastic parity-violating and beam-normal single-spin asymmetries from the 27Al nucleus. Both are the result of ancillary measurements conducted during the Qweak experiment at Jefferson Lab. The goal of the experimental was to determine the proton's weak charge, Qp W, via a measurement of the elastic parity-violating electron-proton scattering asymmetry. During the experiment, ancillary measurements were made with different beam configurations on a separate aluminum alloy target, in an effort to directly measure the aluminum background coming from the experiment's liquid hydrogen target cell. This dissertation discusses three primary results: the parity-violating 27Al asymmetry analysis used to correct for the aluminum target background in the final Qweak analysis, its extended analysis leading to the extraction of the pure elastic parity-violating 27Al asymmetry, and the determination of the elastic beam-normal single-spin 27Al asymmetry. The parity-violating result was also used to make a semi model-independent determination 27Al neutron distribution radius, an important test for models used to describe neutron-rich matter. The beam-normal single-spin asymmetry stands to possibly shed light on an observed disagreement between theory and a previous measurement performed on 208Pb, as 27Al is the next highest atomic mass nucleus to have this observable measured. The elastic parity-violating 27Al asymmetry was found to be $1.927 ± 0.173 ppm at ⟨ Q2 ⟩ = 0.0236 ± 0.0001 GeV2. This measured parity-violating asymmetry implies a 27Al neutron distribution radius of $3.024 ± 0.104 fm. Calculating the difference between this radius and the 27 Al proton distribution radius yields the neutron skin, which was found to be $0.092 ± 0.104 fm. This skin value is consistent with zero, within its uncertainty, and it confirms the naive expectation for a light nucleus like 27Al. The beam-normal single-spin 27Al asymmetry was found to be $-16.322 ± 2.679 ppm at ⟨ Q ⟩ = 0.154 GeV. This value agrees with the previous observed trend of beam-normal single-spin asymmetries measured from light nuclei, which motivates the need for future measurements of higher atomic mass nuclei.

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Adikaram, Dasuni Kalhari. "Direct measurements of two photon exchange on lepton-proton elastic scattering using simultaneous electron-positron beams in CLAS." Thesis, Old Dominion University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3580489.

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The electric (G_E) and magnetic ( G_M) form factors of the proton are fundamental observables which characterize its charge and magnetization distributions. There are two methods to measure the proton form factors: the Rosenbluth separation method and the polarization transfer technique. However, the ratio of the electric and magnetic form factors measured by those methods significantly disagree at momentum transfer Q² > 1 GeV². The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section which significantly changes the extraction of G_E from the Rosenbluth separation measurement. The Jefferson Lab CLAS TPE experiment determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections. The primary electron beam was used to create an intense bremsstrahlung photon beam. Some of the photons were then converted to a mixed e⁺/ e^- beam which then interacted with a liquid hydrogen target. The e⁺p and e^-p events were detected by the CLAS (CEBAF Large Acceptance Spectrometer). The elastic cross section ratios ((σ( e⁺p)/(σ(e^-p)) were measured over a wide range of virtual photon polarization ϵ and Q². The cross section ratios displayed a strong ϵ dependence at Q² = 1.45 GeV². There is no significant Q² dependence observed at ϵ = 0.45. The results are consistent with a recent measurement at the VEPP-3 lepton storage ring in Novosibirsk and with the hadronic calculation by Blunders, Melnitchouk and Tjon. The hadronic calculation resolves the disagreement between the Rosenbluth separation and polarization transfer extractions of G_E/G_M at Q² up to 2 – 3 GeV². Applying the GLAS TPE correction to the Rosenbluth cross section measurements significantly decreases the extracted value of G_E and brings it into good agreement with the polarization transfer measurement at Q²∼1.75 GeV². Thus, these measurements appear to resolve the proton electric form factor discrepancy for Q² < 2 GeV².

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Wijesooriya, Krishni. "First quasi-elastic polarized electron scattering measurement of polarization transfer to protons in a complex nucleus: Oxygen-16." W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539623964.

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The first polarization transfer measurement in the (e,e' p) reaction on a complex nucleus, a study of the exclusive reaction O16e&ar; ,e'p&ar; 15N* , is discussed in this thesis. This experiment was performed at Jefferson Lab, using the Hall A Focal Plane Polarimeter. This was the first experiment to use polarized beam at Jefferson Lab. Simultaneous measurements were also made for the He&ar;, e'p&ar; reaction allowing a precise comparison between the form factor ratios for free and bound protons. Since the helicity-dependent, longitudinal P'l and transverse P't components of the polarization of the recoil proton are sensitive to the electromagnetic form factors GE and GM of the proton inside the nuclear medium, these polarization transfer observables can be used to look for possible medium modification effects on the form factor ratio for the bound proton. The systematic uncertainties involved in performing a recoil polarimetry measurement are minimal, and the theoretical uncertainty (mainly corrections to the Impulse Approximation) are also small. Therefore this measurement provides a sensitive test of the predictions of medium-induced changes in the form factor ratio. Results were obtained for two recoil momentum points, 85 and 140 MeV/c, at a Q2 of 0.8 (GeV/c)2 in quasielastic, perpendicular kinematics. Within statistical uncertainties, the results are in good agreement with theoretical calculations for the polarization observables obtained assuming free values for the form factors, i.e., the results are consistent with the absence of medium modifications of the nucleon electromagnetic structure. This experiment provides a strong basis for the forthcoming high precision measurements of the ratio GE/GM in the nuclear medium.

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Lin, Jun. "Magnetic properties and interlayer coupling of ZnTe/MnTe superlattices /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9974654.

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Edström, Alexander. "Theoretical and Computational Studies on the Physics of Applied Magnetism : Magnetocrystalline Anisotropy of Transition Metal Magnets and Magnetic Effects in Elastic Electron Scattering." Doctoral thesis, Uppsala universitet, Materialteori, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-304666.

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In this thesis, two selected topics in magnetism are studied using theoretical modelling and computational methods. The first of these is the magnetocrystalline anisotropy energy (MAE) of transition metal based magnets. In particular, ways of finding 3d transition metal based materials with large MAE are considered. This is motivated by the need for new permanent magnet materials, not containing rare-earth elements, but is also of interest for other technological applications, where the MAE is a key quantity. The mechanisms of the MAE in the relevant materials are reviewed and approaches to increasing this quantity are discussed. Computational methods, largely based on density functional theory (DFT), are applied to guide the search for relevant materials. The computational work suggests that the MAE of Fe1-xCox alloys can be significantly enhanced by introducing a tetragonality with interstitial B or C impurities. This is also experimentally corroborated. Alloying is considered as a method of tuning the electronic structure around the Fermi energy and thus also the MAE, for example in the tetragonal compound (Fe1-xCox)2B. Additionally, it is shown that small amounts (2.5-5 at.%) of various 5d dopants on the Fe/Co-site can enhance the MAE of this material with as much as 70%. The magnetic properties of several technologically interesting, chemically ordered, L10 structured binary compounds, tetragonal Fe5Si1-xPxB2 and Hexagonal Laves phase Fe2Ta1-xWx are also investigated. The second topic studied is that of magnetic effects on the elastic scattering of fast electrons, in the context of transmission electron microscopy (TEM). A multislice solution is implemented for a paraxial version of the Pauli equation. Simulations require the magnetic fields in the sample as input. A realistic description of magnetism in a solid, for this purpose, is derived in a scheme starting from a DFT calculation of the spin density or density matrix. Calculations are performed for electron vortex beams passing through magnetic solids and a magnetic signal, defined as a difference in intensity for opposite orbital angular momentum beams, integrated over a disk in the diffraction plane, is observed. For nanometer sized electron vortex beams carrying orbital angular momentum of a few tens of ħ, a relative magnetic signal of order 10-3 is found. This is considered realistic to be observed in experiments. In addition to electron vortex beams, spin polarised and phase aberrated electron beams are considered and also for these a magnetic signal, albeit weaker than that of the vortex beams, can be obtained.

Felaktigt ISBN i den tryckta versionen: 9789155497149

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Shepherd, Juliet. "Theoretical studies of slow collisions : elastic electron scattering from positive ions, charge transfer in one-electron ion-ion systems and mutual neutralization of Hâ»/Dâ» and Hâºâ‚‚." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366574.

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Bailey, Stephanie L. "Parity-violation in elastic electron scattering: A first measurement of the parity-violating asymmetry at Q2 = 0.631 (GeV/c)2 at backward angle." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539623510.

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The goal of Experiment E04-115 (the G0 backward angle measurement) at Jefferson Lab is to investigate the contributions of strange quarks to the fundamental properties of the nucleon. The experiment measures parity-violating asymmetries in elastic electron scattering off hydrogen and quasielastic electron scattering off deuterium at backward angles at Q2 = 0.631 (GeV/c)2 and Q 2 = 0.232 (GeV/c)2. The backward angle measurement represents the second phase of the G0 experiment. The first phase, Experiment E00-006 (the G0 forward angle experiment), measured parity-violating asymmetries in elastic electron scattering off hydrogen at forward angles over a Q 2 range of 0.1-1.0 (GeV/c)2. The experiments used a polarized electron beam and unpolarized hydrogen and deuterium liquid targets. From these measurements, along with the electromagnetic form factors, one can extract the contribution of the strange quark to the proton's charge and magnetization distributions.;This thesis represents a first measurement of a parity-violating asymmetry in elastic electron scattering at Q2 = 0.631 (GeV/c) 2 off hydrogen at backward angles. This work is based on data obtained during the first part of the run, beginning in March 2006 and ending in May 2006. During this period, a total of 15 C of beam charge was accumulated. The total accumulated charge represents about 15% of the 110 C which was proposed for this Q2. The measured asymmetry is A = (-47.4 +/- 7.1 +/- 5.9 +/- 11.8) ppm, where the first uncertainty is due to statistics, the second uncertainty is systematic, and the third uncertainty is associated with the blinding factor. This result is consistent with a zero contribution from the strange quarks. The helicity-correlated beam properties and slopes are under adequate control for the final precision of the experiment.

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Kundu, Ashoke. "Monte Carlo simulation of gas-filled radiation detectors." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/987/.

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Waidyawansa, D. Buddhini P. "A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Q_weak Setup." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1375705139.

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Rocadenbosch, Burillo Francesc. "Lidar sensing of the atmosphere: receiver design and inversion algorithms for an elastic system." Doctoral thesis, Universitat Politècnica de Catalunya, 1996. http://hdl.handle.net/10803/6909.

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LIDAR es un acrónimo de LIght Detection And Ranging. En la presente tesis, se usan técnicas basadas en lidar elástico para monitorizar la atmósfera remotamente y derivar información cuantitativa acerca de sus parámetros ópticos. Esta tesis doctoral comprende el diseño y operación de una estación lidar elástica basada en un láser pulsado de Nd:YAG operando a las longitudes de onda de 1064 y 532 nm, en lo que se refiere a los sistemas de recepción, control y diseño de algoritmos de inversión. Básicamente, puede dividirse en tres partes bien diferenciadas: La primera (Caps. 1, 2 y 3) comprende el estudio de la dispersión elástica (Rayleigh y Mie) en la atmósfera, orientada al cálculo del balance de enlace, e intenta vislumbrar la interrelación entre variables físicas tales como la temperatura, la presión y la humedad, y el fenómeno de dispersión, dejando de lado su posible extrapolación a modelos meteorologicos. Partiendo de esta base, se estiman valores de extinción y retrodispersión para diferentes condiciones atmosféricas y, como resultado, se presenta un balance de enlace para el sistema. El mismo incluye el estudio del alcance lidar, la estimación de la relación señal a ruido, y la evaluación de fotodiodos para diferentes librerías del usuario. Esta primera parte se cierra con las especificaciones globales del sistema. La segunda parte de este trabajo (Caps. 4, 5 y 6) atiende al diseño e implemen-tación del receptor, sistemas de sincronización y control. El receptor optoelectrónico se basa en amplificadores realimentados en corriente y cuenta con un excelente producto ganancia ancho de banda. Por lo que respecta al subsistema de sincronismo, se presentan dos unidades distintas con vistas a un futuro sistema lidar de escaneo, lo cuál ofrece la posibilidad de realizar scans entrelazados. Para terminar, el sistema de control diseñado se basa en el software de control LabView, que ofrece una filosofía de control distribuido. Con este propósito, se han especificado e implementado protocolos de bus lidar y su señalización para la presente estación lidar. Finalmente, la tercera parte comprende el diseño de algoritmos de inversión con y sin memoria (Caps. 7 y 8). Los algortimos sin memoria para atmósferas homogéneas se basan en procedimientos de ajuste por regresión como son el método de la pendiente y el de mínimos cuadrados y, en el caso de atmósferas inhomogéneas, se basan en el método de Klett y calibraciones adecuadas. Los algortimos con memoria se basan en diferentes modelos estocásticos para la atmósfera y filtrado de Kalman no lineal. Además de los algortimos de inversión, también se calculan y discuten las curvas del error de inversión. El Cap. 9 describe las medidas llevadas a cabo con el sistema que este trabajo ha permitido construir así como el resultado de aplicar los algoritmos de inversión presentados en los capítulos precedentes. La inversión de escenas reales comprende estudios de la estructura de polución, estudios de nubes (ceilometría, básicamente desplazamiento y estructura de las nubes) y señala posibles fuentes de error en el factor de solapamiento.
LIDAR is an acronym of LIght Detection And Ranging. In the present case, the elastic lidar techniques are used to remotely sense the atmosphere and to derive quantitative information about its optical parameters.This thesis comprises the design and operation of an elastic lidar station based on a pulsed Nd:YAG laser operating at the 1064- and 532-nm wavelengths, in the parts concerning receiver, control systems, and inversion algorithms.Basically, it can be divided in three different parts: The first one (Chaps. 1, 2, and 3) encompasses the study of the elastic scattering (Rayleigh and Mie) in the atmosphere for link-budget purposes and gives some insight into the interweaving between physical variables such as temperature, pressure and humidity, and the scattering phenomena, letting apart any possible extrapolation to meteorological models. From this basis, extinction and backscatter figures for different atmospheric conditions can readily be assessed and, as result, a system link budget is presented. This includes lidar range study, signal-to-noise ratio assessment, and photodiode evaluation from custom-made libraries. At the end of the first part, the system specification is made. The second part of this work (Chaps. 4, 5, and 6) is concerned with the design and implemen-tation of receiver, synchronization, and control systems. The optoelectronic receiver is based on current-feedback amplifiers and features a very large gain-bandwidth product. As for the synchronization subsystem, two different units are presented with a view to a future scanning lidar system, which makes room for interspersed scans. Eventually, the control system designed is LabView based and features a distributed control philosophy. For that purpose, lidar bus protocols and signals are specified and built for the actual lidar station. Finally, the third part encircles the design of inversion algorithms with and without memory (Chaps. 7 and 8). Non-memory algorithms for homogeneous atmospheres are based on regression curve-fitting procedures, such as the slope-method and the least squares while in instances of inhomogeneous atmospheres they are based on Klett's method and appropriate calibrations. Memory algorithms are based on different stochastic models for the atmosphere and on non-linear Kalman filtering. In addition to these inversion procedures, error assessment plots are also derived and discussed. Chap. 9 describes the measurements carried out with the system this work has contributed to build and the results of applying to them the inversion algorithms discussed in the preceding chapters.The inversion of live-scenes involves pollution structure studies, cloud studies (ceilometry, cloud motion and wave clouds, basically), and hints overlap factor error sources.

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Yao, Huan. "Precision Measurement of Longitudinal and Transverse Response Functions of Quasi-Elastic Electron Scattering in the Momentum Transfer Range 0.55 GeV /c ≤ |q| ≤ 1.0 GeV /c." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/152421.

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Physics
Ph.D.
Coulomb Sum Rule states that the integration of the longitudinal response of a nucleus over the range of energy excitation dominated by quasi-elastic proton knock-out process should be equal to the total number of protons in the nucleus. The test of Coulomb Sum Rule will shed light on the question of whether or not the properties of nucleon are modified in the nuclear medium. In order to test the Coulomb Sum Rule in nuclei, a precision measurement of inclusive electron scattering cross sections in the quasi-elastic region was performed at Jefferson Lab. Incident electrons with energies ranging from 0.4 GeV to 4 GeV scattered from 4He, 12C, 56Fe and 208Pb nuclei at four scattering angles ( 15°, 60°, 90°, 120°) and scattered energies ranging from 0.1 GeV to 4 GeV. The Rosenbluth method with proper coulomb corrections is used to extract the transverse and longitudinal response functions at three-momentum transfers in the range 0.55 GeV/c ≤ |q| ≤ 1.0 GeV/c. The Coulomb Sum Rule is determined in the same |q| range and compared to predictions. This work is supported by the Department Of Energy through grant DE-FG02-94ER40844.
Temple University--Theses

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Mammei, Juliette Mae. "Parity-Violating Elastic Electron Nucleon Scattering: Measurement of the Strange Quark Content of the Nucleon and Towards a Measurement of the Weak Charge of the Proton." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/27661.

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The experiments discussed in this thesis exploit parity violation in elastic electron proton scattering in order to measure properties of the nucleon. Both experiments make use of the high quality, highly polarized electron beam available at Thomas Jefferson National Accelerator Facility. Qweak will measure the weak mixing angle, sin²θ_W, via a measurement of the weak charge of the proton, at a four-momentum transfer, Q²~0.026 GeV²/c². The precision of this measurement gives Qweak access to new physics at the scale of 2.3 TeV, making it a test of the standard model. The G0 experimental program provides the fully separated contributions of the strange quark to the charge and magnetization distributions of the nucleon at two different values of four-momentum transfer, Q² ~ 0.22 and 0.63 GeV²/c². The measurement of the strange quark content of the proton in the G0 experimental program and other parity-violating electron scattering experiments provides a measurement of the hadronic contribution to the asymmetry in Qweak. In addition, G0 was able to measure the parity-conserving beam normal single spin asymmetries that provide a measurement of the imaginary part of two photon exchange. The measurement of this asymmetry is necessary to understand the systematic contribution to measurements of parity-violating asymmetries, but it is also an important physics result. Recent theoretical work has shown that higher order radiative effects, such as two photon exchange, may be able to explain discrepancies between experiments which measure the ratio of the electric and magnetic form factors of the proton. The measurement of the transverse or beam normal single spin asymmetries provides a benchmark for theories that estimate the size of radiative corrections that are important for precision electroweak scattering experiments such as those described in this thesis. The results of the measurement of the transverse asymmetries at backward angles in G0 are presented at the two values of Q² ~ 0.22 and 0.63 GeV²/c² for hydrogen. Results for deuterium, which can provide the first measurements of the beam normal single spin asymmetries on the neutron, are also presented.
Ph. D.

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32

Röder, Falk. "Off-Axis Elektronenholographie elastisch und unelastisch gestreuter Elektronen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-115245.

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Die Off-Axis-Elektronenholographie ist eine interferometrische Methode zur experimentellen Bestimmung von relativen Phasenschiebungen einer Elektronenwelle. Der Zugang zu diesen Phasenschiebungen ermöglicht z.B. die Bestimmung von intrinsischen elektrischen und magnetischen Feldern eines Objektes im Nanometerbereich. Für eine quantitative Interpretation der Resultate ist die Kenntnis des Rauschens der holographisch rekonstruierten Größen von hoher Bedeutung. In dieser Arbeit wird ein allgemeiner Formalismus abgeleitet, der den Rauschtransfer vom detektierten Hologramm in die rekonstruierten Amplituden- und Phasenbilder beschreibt. Anhand zielgerichteter Experimente wird dieser Formalismus unter Berücksichtigung von gemessenen Rauscheigenschaften des Detektors verifiziert. Im Zuge dessen wird eine experimentelle Methode entwickelt, die es erlaubt, durch Serienaufnahmen und Mittelungsprozeduren das Signal-zu-Rauschverhältnis in den holographischen Resultaten bei gleichbleibender Ortsauflösung erheblich zu verbessern. Daran knüpft sich eine Vielzahl von Anwendungen an, welche in dieser Arbeit in Auszügen aufgeführt werden. Die Grundlage für all diese Experimente besteht in den Welleneigenschaften des Elektrons, welche in der Interferenzfähigkeit (Kohärenz) des Elektrons zum Ausdruck kommen. Elektronen, welche unelastisch an einem Objekt streuen, verlieren diese Eigenschaft und es stellt sich die Frage, ob aus diesem Verlust zusätzliche Informationen über den Streuprozess bzw. über das Objekt selbst gewonnen werden können. Eine Größe, die neben der Intensität auch die Kohärenz der Elektronen beschreibt, ist die reduzierte Dichtematrix. Das motiviert, die Methode der Off-Axis-Elektronenholographie in der Sprache der Dichtematrizen zu formulieren und eine allgemeine Übertragungstheorie für ein holographiefähiges Transmissionselektronenmikroskop abzuleiten. Diese Theorie umfasst alle bisher bekannten Phänomene im Rahmen der Elektronenholographie und bietet darüber hinaus neue instrumentelle Ansätze zur Optimierung des Signal-zu-Rausch-Verhältnisses und zur Überwindung auflösungsbegrenzender Aberrationen. Vor diesem Hintergrund wird weiterhin die Kohärenz von Elektronen mittels energiegefilterter Off-Axis-Elektronenholographie untersucht, welche unelastisch an Siliziumoberflächen streuen und charakteristische Oberflächenplasmonen anregen. Für die Interpretation der Resultate werden zwei Modelle für die Dekohärenz des Elektrons infolge der Wechselwirkung mit einer Objektoberfläche entwickelt und unter Berücksichtigung der Aberrationen des Energiefilters mit dem Experiment verglichen
Off-axis electron holography provides access to the relative phase shift of an electron wave and allows the experimental determination of intrinsic electric and magnetic fields within an object at nanometre scale. A quantitative interpretation of the results requires the knowledge about the noise in the reconstructed data. In this work, a general formalism is derived describing the transfer of noise from an experimental hologram into reconstructed amplitude and phase images. Concerted experiments verify this formalism under consideration of measured noise properties of the detector. In this frame, a method based on series acquisition and averaging is developed to improve significantly the signal-to-noise ratio of the reconstructed amplitude and phase images at constant spatial resolution. The usefulnes of this method is demonstrated by selected experimental examples from the materials sciences. The capability to show interference, i.e. to be coherent, is a consequence of the electron's wave nature and provides the fundament for all applications of electron holography. By inelastic interaction with the object, the electron loses coherence and the question comes up, whether this loss mechanism contains additional information about the scattering process or even about the object itself. The reduced density matrix is introduced as a suitable quantity describing both intensity and coherence of scattered electrons. That motivates to formulate off-axis electron holography in the language of density matrices and to derive a general transfer theory for this quantity in a holography-dedicated transmission electron microscope. This theory reproduces all known phenomena related to off-axis electron holography and provides new instrumental approaches to improve the signal-to-noise ratio and to overcome resolution limiting aberrations. In this context, the coherence of electrons, which are inelastically scattered by silicon surfaces and have excited characteristic surface plasmons, is investigated by energy-filtered electron holography. For the interpretation of the experimental results, two models are developed for the decoherence of the electron by interaction with an object surface and are compared to the experiment under consideration of the aberrations of the energy-filter

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Záchej, Samuel. "Monte Carlo simulace elektronového rozptylu v rastrovacím prozařovacím elektronovém mikroskopu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242036.

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This thesis deals with an electron scattering in STEM microscopy on objects with dif-ferent shapes, such as cuboid, sphere and hollow capsule. Monte Carlo simulations are used for description of multiple electron scattering. Except the theoretical analysis of the electron scattering and simulation methods, the thesis contains design and realiza-tion of an algorithm simulating electron scattering in given objects. In addition, there is a design for robustness evaluation of the simulation, based on comparison between results and known signals for a given object. Reliability of the algorithm was verified by experimental measurements of the electron scattering on a carbon layer.

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Long, Elena A. "Polarized ³He(e,e'n) Asymmetries in Three Orthogonal Measurements." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1350487441.

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Falk, Saïd. "Diffusion elastique d'electrons (lev-200ev) par des molecules d'interet radiobiologique : contribution a la modelisation de la structure des traces de particules chargees." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13018.

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Developpement d'une approche generale basee sur la formule differentielle de rutherford, avec parametre d'ecran, completee par une formule angulaire parametrique; obtention d'une section efficace differentielle bien adaptee a de nombreuses donnees experimentales et d'une section efficace integree satisfaisante sauf aux tres basses energies de la particule incidente, pour lesquelles on introduit un facteur correctif dependant de deux parametres. Bonne adaptation de ces sections efficaces au code de simulation edifiee au laboratoire pour la modelisation de la structure des traces de particules chargees traversant des tissus vivants

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Ahmed, Md Farid. "Elastic electron scattering from heavy alkali atom /." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR29542.

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Thesis (M.Sc.)--York University, 2007. Graduate Programme in Physics.
Typescript. Includes bibliographical references (leaves 137-141). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR29542

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Huang, Yunfei Polyzou Wayne Nicholas. "Front-form calculations of exchange currents in elastic electron-deuteron scattering." 2008. http://ir.uiowa.edu/etd/217.

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Cranshaw, Jack Mark. "The SMC muon-electron elastic scattering polarimeter." Thesis, 1995. http://hdl.handle.net/1911/16808.

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The Spin Muon Collaboration was formed to measure the spin dependent structure function $g\sb1$ of both the proton and the neutron. This was done by scattering polarized muons off of polarized protons or deuterons. The results provided a test of three sum rules: the Ellis-Jaffe sum rule for the proton, the Ellis-Jaffe sum rule for the neutron, and the Bjorken sum rule. Two polarimeters were used to measure the beam polarization. The polarimeter discussed in this thesis used elastic scattering from polarized electrons to measure the muon beam polarization. It gave a result in agreement with both the previous measurement using muon decay and a simulation of the beamline. These measurements helped reduce the systematic error on the measurement and improve the measurements of the sum rules. The results from the experiment showed that both Ellis-Jaffe sum rules were violated while the Bjorken sum rule was confirmed.

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Chen, Yu-Chun, and 陳佑駿. "Two-Photon Exchange Effect in the Elastic Electron-Nucleon Scattering." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/26172793068704348562.

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博士
國立臺灣大學
物理研究所
95
When measuring the nucleon form factors, recent polarization experiments at the Thomas Jefferson Laboratory (JLab) have confirmed the earlier Rosenbluth measurements from SLAC at small Q2. However, at large Q2, a huge discrepancy appear between them. To solve this puzzle, the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering was estimated. And then we thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments. Now we know higher-order QED effects can play an important role in precision measurements of nucleon elastic form factors in electron scattering.

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Chen, Yu-Chun. "Two-Photon Exchange Effect in the Elastic Electron-Nucleon Scattering." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1007200704235500.

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41

Dunford, Jeffrey Loren. "Elastic Scattering Phenomena in Molecularly-linked Gold Nanoparticle Films." Thesis, 2008. http://hdl.handle.net/1807/16725.

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We have investigated the conductance, g, of 1,4-butanedithiol linked Au nanoparticle films as a function of temperature, T, bias potential, V, and applied magnetic field, B. An interesting temperature dependence is observed for non-metallic films with thicknesses just below a critical film thickness: g ~ exp [-(T_0/T)^(1/2)] for 20 K < T < 300 K. We show that this temperature dependence is incompatible with an Efros-Shklovskii "variable range hopping" model, since "hopping distances" are too large to be consistent with tunneling processes, and tend to scale with size of super-clusters of molecularly-linked nanoparticles. We propose a "quasilocalized hopping" model based on competition between single-electron charging of super-clusters and electron backscattering within super-clusters to explain the observed temperature dependence. Various electron scattering time scales are extracted from magnetoconductance data using a modified "weak localization" model. Elastic scattering time scales are comparable to those required for an electron to traverse a nanoparticle, while inelastic and spin-orbit scattering time scales are consistent with those found in studies of conventionally-prepared granular Au films. At interfaces between metallic 1,4-butanedithiol-linked Au nanoparticle films and conventional superconductors, we find that g consistently exhibits peaks, as well as oscillations, that depend simultaneously on both V and B. Such peaks and correlated conductance oscillations are predicted by an enhanced Andreev reflection process due to disorder-driven elastic scattering and electron-hole interference in the nanoparticle film. While oscillations have been predicted by a so-called "reflectionless tunneling" model, they have not been observed at other normal-superconductor interfaces. We speculate that oscillations are observable in this system due to synthetically controlled uniformity of elastic scattering length (i.e., nanoparticle diameter) and a reduced number of current-carrying pathways, especially near the interface. Contrary to predictions of existing "reflectionless tunneling" models, we find that the periods of oscillation in B decrease as T increases. This suggests that the area of interfering pathways increases with T. We propose that this increasing area can be attributed to magnetic field penetration into the superconductor. Conductance data agrees remarkably well with known temperature dependence of penetration depth predicted by BCS theory. Our study shows that this additional region of flux must be considered in experimental and theoretical studies of "reflectionless tunneling", and underscores the utility of molecularly-linked nano\-particle films as a platform for studying charge transport.

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42

"Measurement of the Two-Photon Exchange Contribution to Lepton-Proton Scattering with OLYMPUS." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40823.

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abstract: The OLYMPUS experiment measured the two-photon exchange contribution to elastic electron-proton scattering, over a range of four-momentum transfer from $0.6 < Q^2 < 2.2$ $(\mathrm{GeV/c})^2$. The motivation for the experiment stemmed from measurements of the electric-to-magnetic form factor ratio of the proton $\mu G_E/G_M$ extracted from polarization observables in polarized electron-proton scattering. Polarized electron-proton scattering experiments have revealed a significant decrease in $\mu G_E/G_M$ at large $Q^2$, in contrast to previous measurements from unpolarized electron-proton scattering. The commonly accepted hypothesis is that the discrepancy in the form factor ratio is due to neglected higher-order terms in the elastic electron-proton scattering cross section, in particular the two-photon exchange amplitude. The goal of OLYMPUS was to measure the two-photon exchange contribution by measuring the positron-proton to electron-proton elastic scattering cross section ratio, $\sigma_{e^+p}/\sigma_{e^-p}$. The two-photon exchange contribution is correlated to the deviation of the cross section ratio from unity. In 2012, the OLYMPUS experiment collected over 4 fb$^{-1}$ of $e^+p$ and $e^-p$ scattering data using electron and positron beams incident on a hydrogen gas target. The scattered leptons and protons were measured exclusively with a large acceptance spectrometer. OLYMPUS observed a slight rise in $\sigma_{e^+p}/\sigma_{e^-p}$ of at most 1-2\% over a $Q^2$ range of $0.6 < Q^2 < 2.2$ $(\mathrm{GeV/c})^2$. This work discusses the motivations, experiment, analysis method, and the preliminary results for the cross section ratio as measured by OLYMPUS.
Dissertation/Thesis
Doctoral Dissertation Physics 2016

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43

Potterveld, David Henry. "A measurement of inclusive quasi-elastic electron scattering cross sections at high momentum transfer." Thesis, 1989. https://thesis.library.caltech.edu/7831/1/Potterveld-dh-1989.pdf.

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We have measured inclusive electron-scattering cross sections for targets of ^(4)He, C, Al, Fe, and Au, for kinematics spanning the quasi-elastic peak, with squared, four momentum transfers (q^2) between 0.23 and 2.89 (GeV/c)^2. Additional data were measured for Fe with q^2's up to 3.69 (GeV/c)^2 These cross sections were analyzed for the y-scaling behavior expected from a simple, impulse-approximation model, and are found to approach a scaling limit at the highest q^2's. The q^2 approach to scaling is compared with a calculation for infinite nuclear matter, and relationships between the scaling function and nucleon momentum distributions are discussed. Deviations from perfect scaling are used to set limits on possible changes in the size of nucleons inside the nucleus.

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CAI, WEN-REN, and 蔡文仁. "Electron-He atom elastic scattering using correlated wave function for the ground state of the atom." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/12034631765557201792.

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45

Uka, Arban. "Quantum state resolved studies of copper-H₂ system and electronic spectroscopy of Cu(100)." 2009. http://hdl.handle.net/2152/10638.

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Hydrogen quantum state resolved energy losses upon scattering from copper are studied using molecular beam techniques and quantum state-specific detection methods. Also clean copper and hydrogen and oxygen covered copper surfaces were studied using electron spectroscopy. There are many questions about the nature of molecule-surface dynamics and the processes. The relative role of the different degrees of freedom in the reaction and the importance of non-adiabatic effects have been two of these questions. These two questions motivated this work. Energy loss in the elastic scattering of H₂(v=1. J=1) and H₂(v=0, J=1) molecular quantum states is measured as a function of incident translational energy at two surface temperatures. The energy loss process is shown to agree to the Baule classical model for energy ranges 74-150 meV for the excited vibrationally state and 74-125 for the ground vibrational state. Results suggest that translational energy is more effective that vibrational energy in the observed process. Theoretical models have been able to explain several processes using nonadiabatic models where friction coefficient tensor is included. Results in this thesis suggest that the energy loss in the elastic scattering is a nonadiabatic one. Electron spectroscopy studies showed that the surface plasmon intensity is very sensitive to surface contamination. Using this property, surface-only sensitive virtual temperature programmed desorption (VTPD) is developed. A better understanding of unique behavior of hydrogen covered Cu(100) was gained.
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46

Lee, Li-Ling, and 李麗玲. "The study of elastic scattering of electron and hydrogen atom by hyperbolic Eikonal approximation with a model potential." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/19939891662395196104.

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碩士
國立交通大學
電子物理學系
82
Hyperbolic Eikonal approximation was employed to study the electron-hydrogen differential crossl potential was used to replace the Coulomb potential adopted usually between the electron and hydrogen atom. This model potential had been shown to be able reproduce theof negative hydrogen ion and the low energy electron-hydrogen scattering phasethis model potential can not meet the observed scattering data at all. In order to reproduce the higher energy scattering data, the interaction strength parameters of the model potential were adjusted to fit the observed data at certain incident energy of electron by least-squares calculation. It was found that the new fitted model potential can only reproduce the high energyen differential cross section fairly well. Further investigation is certainly required.

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Lin, Shin-Ted. "Measurement of Neutrino-electron elastic scattering with a CsI(Tl) crystal array at the Kuo-Sheng Reactor Neutrino Laboratory." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2501200615103300.

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Shin-Ted, Lin, and 林興德. "Measurement of Neutrino-electron elastic scattering with a CsI(Tl) crystal array at the Kuo-Sheng Reactor Neutrino Laboratory." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/56864375432023030660.

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博士
國立臺灣大學
物理研究所
94
Reactors are well suited to study ee scattering. Both charged current (CC) and neutral weak currents (NC) are involved in the Standard Model. A measurement of the differential cross section allows to determine the Weinberg angle sin2 W. and to observe the interference which is expected to be destructive for reasonable values of sin2 W. This thesis will focus on untested few MeV range. To measure the ee􀀀 scattering, the strategy is to choose on high (>3 MeV) recoil energy above those from natural radioactivity, with the additional merits of having good accuracies in the knowledge of the reactor anti-neutrino spectra. The large target mass compensates the drop in the cross-sections. Selecting lone events,basically neutrino ones, adopted veto of cosmic ray,"Single Hit" and pulse shape discrimination(PSD). According to the PSD capabilities of the crystal, as well as the temporal and spatial correlation of the events, allow a sensitive measurement of intrinsic radio-purity of 235U, 238U and 232Th series. Their concentration gradients with the crystal growth axis, and uniformity among di erent crystal samples, are discovered. This analysis not only provides in the measurement of the detector performance parameters, such as spatial resolution and quenching factors, but also reduces the background due to the contamination with 0.0085 kg􀀀1day􀀀1 at 3 5 MeV. A preliminary background level of 0.412 kg􀀀1day􀀀1 at 3 8 MeV, were achieved based on 5592 and 2079 kg-day of reactor ON and OFF data in Period II 1. After subtracting ON and OFF data, we got the e event rate level of 0:0320 0:0167 kg􀀀1day􀀀1 at 3 8 MeV. The best t of sin2 w,0:37+- 0:13 at 3 8 MeV, 0:30+- 0:22 at 3.5 8 MeV respectively have been carried out. The possibilities of reducing background further can be the PSD as thefunction of 2 related to r/e reference pulses, global- t method, more data accumulated which already has another 27000 kg-day 2 on hand and the coming Period IV 3 On the other hand, background understanding corresponding to the 2-hit and 3-hit analysis, including the pair production e ect, 208Tl contamination and ine cient cosmic ray, the preliminary data has been able to explain the dominating background. The expect result of the interaction of e-e Scattering cross section can achieve better than 5 measurement, <8% accuracy of sin2 w, and 4 measurement of destructive interference term.

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Mikuš, Pavel. "Simulace formování obrazu v elektronovém mikroskopu pomocí sledování elektronů." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-438060.

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Cryogenic electron microscopy (cryo-EM) is an evolving field allowing molecular visu- alizations with picometer resolutions. Images are acquired by shooting electrons through molecular samples and detecting the scattered electrons. From such data, 3D shapes of the molecules can be inversely reconstructed. Currently, describing and simulating the cryo-EM image formation is based either on naive transmittance models or complicated wave-function formalisms. In this thesis, we explore the possibility of simulating cryo-EM image formation via Monte Carlo electron tracing. We combine a delta-tracking algorithm with an elec- tron elastic differential cross-section function and Rutherford formulae to derive two Monte Carlo estimators. The derived models are implemented in a high-performance C++/CUDA environment and compared with other common models. Our particle-based simulated images show considerable similarity to the wave-based state-of-the-art multi- slice model. We also evaluate our models on class averages of real measurements. Both of our proposed models have significantly higher normalized cross-correlation scores with the measured class averages when compared to the most commonly used transmittance model. The thesis proves the viability of a particle-based Monte Carlo simulation of elec- tron microscope...

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Loupas, Alexandra Cristina Rodrigues. "Study of Low-energy Electron Collisions with Molecules of Biological Relevance." Doctoral thesis, 2019. http://hdl.handle.net/10362/93349.

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This thesis is focused on the application of the R-matrix method, as implemented in the UKRmol and UKRmol+ suites, to study low-energy electron collisions with three medium-sized molecules of biological relevance: para-benzoquinone, thiophene and alanine. Our goals for all the targets are mainly three: (i) to identify and characterize respective resonances; (ii) to calculate elastic and inelastic integral and elastic differential cross sections; and (iii) compare our results with the literature. To do so, we use several scattering models, choosing the most suitable on the basis of the characteristics being investigated: Static Exchange, Static Exchange plus Polarization and/or Close-Coupling approximation. Specially at higher energies, we find an unexpectedly large number of resonances for the three targets, most of them of core-excited and core-excited shape character. We compare our results with other calculations and/or experiments in the literature, but the absence of detailed experimental results for many targets at these energies precludes a meaningful comparison. Nonetheless, three scenarios are then obtained: in the first one, for para-benzoquinone, the agreement with previous results is satisfactory; in the second, for thiophene, is excellent; and finally, for alanine, there is not much prior information on the literature to make decisive conclusions. This work was all published in peer-reviewed journals.

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Dissertations / Theses on the topic '(*ELECTRONS, ELASTIC SCATTERING)'

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