Separable representation of energy-dependent optical potentials
Hlophe, L.; Elster, Ch.
2016-03-01
Background: One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship are cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, indirect methods, e.g., (d ,p ) reactions, should be used. Those (d ,p ) reactions may be viewed as three-body reactions and described with Faddeev techniques. Purpose: Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupled integral equations in one variable. Optical potentials representing the effective interactions in the neutron (proton) nucleus subsystem are usually non-Hermitian as well as energy dependent. Potential matrix elements as well as transition matrix elements calculated with them must fulfill the reciprocity theorem. The purpose of this paper is to introduce a separable, energy-dependent representation of complex, energy-dependent optical potentials that fulfill reciprocity exactly. Methods: Momentum space Lippmann-Schwinger integral equations are solved with standard techniques to obtain the form factors for the separable representation. Results: Starting from a separable, energy-independent representation of global optical potentials based on a generalization of the Ernst-Shakin-Thaler (EST) scheme, a further generalization is needed to take into account the energy dependence. Applications to n +48Ca ,n +208Pb , and p +208Pb are investigated for energies from 0 to 50 MeV with special emphasis on fulfilling reciprocity. Conclusions: We find that the energy-dependent separable representation of complex, energy-dependent phenomenological optical potentials fulfills reciprocity exactly. In addition, taking into account the explicit energy dependence slightly improves the description of the S matrix elements.
Separable Representation of Energy-Dependent Optical Potentials
Hlophe, Linda
2015-01-01
Background. One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship are cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, indirect methods, e.g. (d,p) reactions, should be used. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques. Purpose. Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupled integral equations in one variable. Optical potentials representing the effective interactions in the neutron (proton) nucleus subsystem are usually non-Hermitian as well as energy-dependent. Potential matrix elements as well as transition matrix elements calculated with them must fulfill the reciprocity theorem. The purpose of this paper is to introduce a separable, energy-dependent representation of complex, energy-dependent optical potentials that fulfill reciprocity e...
HZEFRG1: An energy-dependent semiempirical nuclear fragmentation model
Townsend, Lawrence W.; Wilson, John W.; Tripathi, Ram K.; Norbury, John W.; Badavi, Francis F.; Khan, Ferdous
1993-01-01
Methods for calculating cross sections for the breakup of high-energy heavy ions by the combined nuclear and coulomb fields of the interacting nuclei are presented. The nuclear breakup contributions are estimated with an abrasion-ablation model of heavy ion fragmentation that includes an energy-dependent, mean free path. The electromagnetic dissociation contributions arising from the interacting coulomb fields are estimated by using Weizsacker-Williams theory extended to include electric dipole and electric quadrupole contributions. The complete computer code that implements the model is included as an appendix. Extensive comparisons of cross section predictions with available experimental data are made.
Energy-Dependent Octagonal Lattice Boltzmann Modeling for Compressible Flows
Pavlo, Pavol; Vahala, Linda; Vahala, George
2000-10-01
There has been much interest in thermal lattice Boltzmann modeling (TLBM) for compressible flows because of their inherent parallelizeability. Instead of applying CFD techniques to the nonlinear conservation equations, one instead solves a linear BGK kinetic equation. To reduce storage requirements, the velocity space is discretized and lattice geometries are so chosen to minimize the number of degrees of freedom that must be retained in the Chapman-Enskog recovery of the original macroscopic equations. The simplest (and most efficient) TLBM runs at a CFL=1, so that no numerical diffusion or dissipation is introduced. The algorithm involves Lagrangian streaming (shift operator) and purely local operations. Because of the underlying discrete lattice symmetry, the relaxation distributions cannot be Maxwellian and hence the inherent numerical instability problem in TLBM. We are investigating the use of energy-dependent lattices so as to allow simulation of problems of interest in divertor physics, The appeal of TLBM is that it can provide a unified representation for both strongly collisional (‘fluid’) and weakly collisional (‘Monte Carlo’) regimes. Moreover, our TLBM code is more efficiently solved on mulit-PE platforms than the corresponding CFD codes and is readily extended to 3D. MHD can also be handled by TLBM.
Maridi H. M.
2016-01-01
Full Text Available 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.
Kawaguchi, Ai; Matsunaga, Yuta; Suzuki, Shoichi; Chida, Koichi
2017-03-01
This study aimed to investigate the energy dependence and the angular dependence of commercially available optically stimulated luminescence (OSL) point dosimeters in the mammography energy range. The energy dependence was evaluated to calculate calibration factors (CFs). The half-value layer range was 0.31-0.60 mmAl (Mo/Mo 22-28 kV, Mo/Rh 28-32 kV, and W/Rh 30-34 kV at 2-kV intervals). Mo/Rh 28 kV was the reference condition. Angular dependence was tested by rotating the X-ray tube from -90° to 90° in 30° increments, and signal counts from angled nanoDots were normalized to the 0° signal counts. Angular dependence was compared with three tube voltage and target/filter combinations (Mo/Mo 26 kV, Mo/Rh 28 kV and W/Rh 32 kV). The CFs of energy dependence were 0.94-1.06. In Mo/Mo 26-28 kV and Mo/Rh 28-32 kV, the range of CF was 0.99-1.01, which was very similar. For angular dependence, the most deteriorated normalized values (Mo/Mo, 0.37; Mo/Rh, 0.43; and W/Rh, 0.58) were observed when the X-ray tube was rotated at a 90° angle, compared to 0°. The most angular dependences of ± 30°, 60°, and 90° decreased by approximately 4%, 14%, and 63% respectively. The mean deteriorated measurement 30° intervals from 0° to ± 30° was 2%, from ± 30° to ± 60° was 8%, and from ± 60° to ± 90° was 40%. The range of energy dependence in typical mammography energy range was not as much as that in general radiography and computed tomography. For accurate measurement using nanoDot, the tilt needs to be under 30°.
Modelling of OPNMR phenomena using photon energy-dependent in GaAs and InP
Wheeler, Dustin D.; Willmering, Matthew M.; Sesti, Erika L.; Pan, Xingyuan; Saha, Dipta; Stanton, Christopher J.; Hayes, Sophia E.
2016-12-01
We have modified the model for optically-pumped NMR (OPNMR) to incorporate a revised expression for the expectation value of the z-projection of the electron spin, and apply this model to both bulk GaAs and a new material, InP. This expression includes the photon energy dependence of the electron polarization when optically pumping direct-gap semiconductors in excess of the bandgap energy, Eg . Rather than using a fixed value arising from coefficients (the matrix elements) for the optical transitions at the k = 0 bandedge, we define a new parameter, Sopt (Eph) . Incorporating this revised element into the expression for , we have simulated the photon energy dependence of the OPNMR signals from bulk semi-insulating GaAs and semi-insulating InP. In earlier work, we matched calculations of electron spin polarization (alone) to features in a plot of OPNMR signal intensity versus photon energy for optical pumping (Ramaswamy et al., 2010). By incorporating an electron spin polarization which varies with pump wavelength into the penetration depth model of OPNMR signal, we are able to model features in both III-V semiconductors. The agreement between the OPNMR data and the corresponding model demonstrates that fluctuations in the OPNMR intensity have particular sensitivity to light hole-to-conduction band transitions in bulk systems. We provide detailed plots of the theoretical predictions for optical pumping transition probabilities with circularly-polarized light for both helicities of light, broken down into illustrative plots of optical magnetoabsorption and spin polarization, shown separately for heavy-hole and light-hole transitions. These plots serve as an effective roadmap of transitions, which are helpful to other researchers investigating optical pumping effects.
Modelling the energy dependencies of high-frequency QPO in black hole X-ray binaries
Zycki, P. T.; A. Niedzwiecki(University of Lodz, Poland); Sobolewska, M. A.
2007-01-01
We model energy dependencies of the quasi periodic oscillations (QPO) in the model of disc epicyclic motions, with X-ray modulation caused by varying relativistic effects. The model was proposed to explain the high frequency QPO observed in X-ray binaries. We consider two specific scenarios for the geometry of accretion flow and spectral formation. Firstly, a standard cold accretion disc with an active X-ray emitting corona is assumed to oscillate. Secondly, only a hot X-ray emitting accretio...
Energy-dependent dipole form factor in a QCD-inspired model
Bahia, C A S; Luna, E G S
2015-01-01
We consider the effect of an energy-dependent dipole form factor in the high-energy behavior of the forward amplitude. The connection between the semihard parton-level dynamics and the hadron-hadron scattering is established by an eikonal QCD-based model. Our results for the proton-proton ($pp$) and antiproton-proton ($\\bar{p}p$) total cross sections, $\\sigma_{tot}^{pp,\\bar{p}p}(s)$, obtained using the CTEQ6L1 parton distribution function, are consistent with the recent data from the TOTEM experiment.
Energy-dependent dipole form factor in a QCD-inspired model
Bahia, C. A. S.; Broilo, M.; Luna, E. G. S.
2016-04-01
We consider the effect of an energy-dependent dipole form factor in the high-energy behavior of the forward amplitude. The connection between the semihard parton-level dynamics and the hadron-hadron scattering is established by an eikonal QCD-based model. Our results for the proton-proton (pp) and antiproton-proton (¯pp) total cross sections, σpp,\\bar{pp}tot(s), obtained using the CTEQ6L1 parton distribution function, are consistent with the recent data from the TOTEM experiment.
Modelling the energy dependencies of high-frequency QPO in black hole X-ray binaries
Zycki, P T; Sobolewska, M A
2007-01-01
We model energy dependencies of the quasi periodic oscillations (QPO) in the model of disc epicyclic motions, with X-ray modulation caused by varying relativistic effects. The model was proposed to explain the high frequency QPO observed in X-ray binaries. We consider two specific scenarios for the geometry of accretion flow and spectral formation. Firstly, a standard cold accretion disc with an active X-ray emitting corona is assumed to oscillate. Secondly, only a hot X-ray emitting accretion flow oscillates, while the cold disc is absent at the QPO radius. We find that the QPO spectra are generally similar to the spectrum of radiation emitted at the QPO radius, and they are broadened by the relativistic effects. In particular, the QPO spectrum contains the disc component in the oscillating disc with a corona scenario. We also review the available data on energy dependencies of high frequency QPO, and we point out that they appear to lack the disc component in their energy spectra. This would suggest the hot...
Beam energy dependence of Hanbury-Brown-Twiss radii from a blast-wave model
Zhang, S; Chen, J H; Zhong, C
2016-01-01
Beam energy dependence of correlation lengths (Hanbury-Brown-Twiss radii) is calculated by using a blast-wave model and the results are comparable with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE measurements. The parameters for the blast-wave model as a function of beam energy are configured by fitting Hanbury-Brown-Twiss radii at each energy point. Transverse momentum dependence of Hanbury-Brown-Twiss radii are presented with the extracted parameters for $\\sqrt{s_{NN}} = $ 200 GeV and 2.76 TeV. From the results it can be found that particle emission duration can not be ignored while calculating Hanbury-Brown-Twiss radii with the same parameters. And tuning kinetic freeze-out temperature in a range will result in system lifetime changing in reverse direction as that in RHIC-STAR measurements.
Schulze-Halberg, Axel; Roy, Pinaki
2017-03-01
We construct energy-dependent potentials for which the Schrödinger equations admit solutions in terms of exceptional orthogonal polynomials. Our method of construction is based on certain point transformations, applied to the equations of exceptional Hermite, Jacobi and Laguerre polynomials. We present several examples of boundary-value problems with energy-dependent potentials that admit a discrete spectrum and the corresponding normalizable solutions in closed form.
Schulze-Halberg, Axel, E-mail: axgeschu@iun.edu [Department of Mathematics and Actuarial Science, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Department of Physics, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Roy, Pinaki, E-mail: pinaki@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India)
2017-03-15
We construct energy-dependent potentials for which the Schrödinger equations admit solutions in terms of exceptional orthogonal polynomials. Our method of construction is based on certain point transformations, applied to the equations of exceptional Hermite, Jacobi and Laguerre polynomials. We present several examples of boundary-value problems with energy-dependent potentials that admit a discrete spectrum and the corresponding normalizable solutions in closed form.
Energy dependent model of a metal oxide surge arrester. Sanka aengata hiraiki no energy izon model
Kojima, S.; Kan, M.; Masuzawa, K. (Toshiba Corp., Tokyo (Japan))
1994-03-20
This paper reports on modeling a zinc-oxide lightning arrester. The paper indicates that it is difficult to model the zinc-oxide elements by using non-linear resistance and inductance only, based on results of measuring hysteresis curves of restriction voltage on dual peak discharge of the elements. The paper then proposes a model (of numerical expression) that incorporates a concept that the restriction voltage decreases in response to energy absorbed by the elements from the discharge current. The paper explains a method for deciding on constants contained in the proposed expression, and a method to calculate the restriction voltage according to the proposed expression by using TACS of the program EMTP for circuit analysis. Further, it is indicated that the measured values of the restriction voltage on the dual-peak discharge current agree well with the calculated values from the proposed expression. A comparison was made on effects of this model and the conventional non-linear resistance model on the results of analyzing lightning surge responses in a 500-kV model system. 6 refs., 14 figs., 1 tab.
Xu, Jun
2016-01-01
Based on an extended multiphase transport model, which includes mean-field potentials in both the partonic and hadronic phases, uses the mix-event coalescence, and respects charge conservation during the hadronic evolution, we have studied the collision energy dependence of the elliptic flow splitting between particles and their antiparticles. This extended transport model reproduces reasonably well the experimental data at lower collision energies but only describes qualitatively the elliptic flow splitting at higher beam energies. The present study thus indicates the existence of other mechanisms for the elliptic flow splitting besides the mean-field potentials and the need of further improvements of the multiphase transport model.
Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo
2016-01-01
For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.
A microstructure- and surface energy-dependent third-order shear deformation beam model
Gao, X.-L.; Zhang, G. Y.
2015-08-01
A new non-classical third-order shear deformation model is developed for Reddy-Levinson beams using a variational formulation based on Hamilton's principle. A modified couple stress theory and a surface elasticity theory are employed. The equations of motion and complete boundary conditions for the beam are obtained simultaneously. The new model contains a material length scale parameter to account for the microstructure effect and three surface elastic constants to describe the surface energy effect. Also, Poisson's effect is incorporated in the new beam model. The current non-classical model recovers the classical elasticity-based third-order shear deformation beam model as a special case when the microstructure, surface energy and Poisson's effects are all suppressed. In addition, the newly developed beam model includes the models considering the microstructure dependence or the surface energy effect alone as limiting cases and reduces to two existing models for Bernoulli-Euler and Timoshenko beams incorporating the microstructure and surface energy effects. To illustrate the new model, the static bending and free vibration problems of a simply supported beam loaded by a concentrated force are analytically solved by directly applying the general formulas derived. For the static bending problem, the numerical results reveal that both the deflection and rotation of the simply supported beam predicted by the current model are smaller than those predicted by the classical model. Also, it is observed that the differences in the deflection and rotation predicted by the two beam models are very large when the beam thickness is sufficiently small, but they are diminishing with the increase in the beam thickness. For the free vibration problem, it is found that the natural frequency predicted by the new model is higher than that predicted by the classical beam model, and the difference is significant for very thin beams. These predicted trends of the size effect at the
Models and numerical methods for time- and energy-dependent particle transport
Olbrant, Edgar
2012-04-13
Particles passing through a medium can be described by the Boltzmann transport equation. Therein, all physical interactions of particles with matter are given by cross sections. We compare different analytical models of cross sections for photons, electrons and protons to state-of-the-art databases. The large dimensionality of the transport equation and its integro-differential form make it analytically difficult and computationally costly to solve. In this work, we focus on the following approximative models to the linear Boltzmann equation: (i) the time-dependent simplified P{sub N} (SP{sub N}) equations, (ii) the M{sub 1} model derived from entropy-based closures and (iii) a new perturbed M{sub 1} model derived from a perturbative entropy closure. In particular, an asymptotic analysis for SP{sub N} equations is presented and confirmed by numerical computations in 2D. Moreover, we design an explicit Runge-Kutta discontinuous Galerkin (RKDG) method to the M{sub 1} model of radiative transfer in slab geometry and construct a scheme ensuring the realizability of the moment variables. Among other things, M{sub 1} numerical results are compared with an analytical solution in a Riemann problem and the Marshak wave problem is considered. Additionally, we rigorously derive a new hierarchy of kinetic moment models in the context of grey photon transport in one spatial dimension. For the perturbed M{sub 1} model, we present numerical results known as the two beam instability or the analytical benchmark due to Su and Olson and compare them to the standard M{sub 1} as well as transport solutions.
Stress fiber response to mechanics: a free energy dependent statistical model.
Jiang, Li; Yang, Chun; Zhao, Lei; Zheng, Quanshui
2014-07-14
An experimental observation has been puzzling scientists for years: cells tend to align perpendicular to cyclic uniaxial strain, but parallel to external static strain. Recent experimental results demonstrate that both the magnitude of the external strain and the cell contractility manipulate the cells' orientation under cyclic uniaxial strain. In light of these reports, we introduce a minimum free energy model to explain the different orientation tendencies of cells subjected to external strain, and elucidate the significant role of cell contractility in this issue. With the present model, we successfully explain a series of well-documented phenomena: (1) cells orient nearly parallel to static uniaxial strain; (2) cell alignment depends on the magnitude of the cyclic uniaxial strain; (3) under cyclic uniaxial stretch, a tensioned contractility results in a strengthened perpendicular alignment of the cells, whereas a contractility relaxation results in a nearly parallel alignment. In addition, this model also successfully describes the functional relationship between cell contractility and substrate stiffness.
Potgieter, M. S.; Le Roux, J. A.
1992-01-01
The time-dependent cosmic-ray transport equation is solved numerically in an axially symmetric heliosphere. Gradient and curvature drifts are incorporated, together with an emulated wavy neutral sheet. This model is used to simulate heliospheric cosmic-ray modulation for the period 1985-1989 during which drifts are considered to be important. The general energy dependence of the modulation of Galactic protons is studied as predicted by the model for the energy range 1 MeV to 10 GeV. The corresponding instantaneous radial and latitudinal gradients are calculated, and it is found that, whereas the latitudinal gradients follow the trends in the waviness of the neutral sheet to a large extent for all energies, the radial gradients below about 200 MeV deviate from this general pattern. In particular, these gradients increase when the waviness decreases for the simulated period 1985-1987.3, after which they again follow the neutral sheet by increasing rapidly.
Mustonen, Ville; Kinney, Justin; Callan, Curtis G; Lässig, Michael
2008-08-26
We present a genomewide cross-species analysis of regulation for broad-acting transcription factors in yeast. Our model for binding site evolution is founded on biophysics: the binding energy between transcription factor and site is a quantitative phenotype of regulatory function, and selection is given by a fitness landscape that depends on this phenotype. The model quantifies conservation, as well as loss and gain, of functional binding sites in a coherent way. Its predictions are supported by direct cross-species comparison between four yeast species. We find ubiquitous compensatory mutations within functional sites, such that the energy phenotype and the function of a site evolve in a significantly more constrained way than does its sequence. We also find evidence for substantial evolution of regulatory function involving point mutations as well as sequence insertions and deletions within binding sites. Genes lose their regulatory link to a given transcription factor at a rate similar to the neutral point mutation rate, from which we infer a moderate average fitness advantage of functional over nonfunctional sites. In a wider context, this study provides an example of inference of selection acting on a quantitative molecular trait.
Ripoll, J.-F.; Reeves, G. D.; Cunningham, G. S.; Loridan, V.; Denton, M.; Santolík, O.; Kurth, W. S.; Kletzing, C. A.; Turner, D. L.; Henderson, M. G.; Ukhorskiy, A. Y.
2016-06-01
We present dynamic simulations of energy-dependent losses in the radiation belt "slot region" and the formation of the two-belt structure for the quiet days after the 1 March storm. The simulations combine radial diffusion with a realistic scattering model, based data-driven spatially and temporally resolved whistler-mode hiss wave observations from the Van Allen Probes satellites. The simulations reproduce Van Allen Probes observations for all energies and L shells (2-6) including (a) the strong energy dependence to the radiation belt dynamics (b) an energy-dependent outer boundary to the inner zone that extends to higher L shells at lower energies and (c) an "S-shaped" energy-dependent inner boundary to the outer zone that results from the competition between diffusive radial transport and losses. We find that the characteristic energy-dependent structure of the radiation belts and slot region is dynamic and can be formed gradually in ~15 days, although the "S shape" can also be reproduced by assuming equilibrium conditions. The highest-energy electrons (E > 300 keV) of the inner region of the outer belt (L ~ 4-5) also constantly decay, demonstrating that hiss wave scattering affects the outer belt during times of extended plasmasphere. Through these simulations, we explain the full structure in energy and L shell of the belts and the slot formation by hiss scattering during storm recovery. We show the power and complexity of looking dynamically at the effects over all energies and L shells and the need for using data-driven and event-specific conditions.
Modeling the Energy Dependent Pulse Profiles of the Accreting Millisecond Pulsar SAX J1808.4-3658
Poutanen, J; Poutanen, Juri; Gierlinski, Marek
2002-01-01
The pulse profiles of the accreting X-ray millisecond pulsar SAX J1808.4-3658 at different energies are studied. The two main emission component, a black body and a power-law tail, clearly identified in the time-averaged spectrum, do not vary in phase. We show that the observed variability can be easily explained if the emission patterns of the black body and the Comptonized radiation are different: a "knife" and a "fan"-like, respectively. We suggest that Comptonization in a hot slab (radiative shock) of Thomson optical depth \\~0.3 at the surface of the neutron star may be responsible for the emission. We construct a detailed model of the X-ray production accounting for the Doppler boosting, relativistic aberration and gravitational light bending. The model reproduces well the pulse profiles at different energies simultaneously, corresponding phase lags, as well as the time-averaged spectrum. By fitting the observed pulse profiles we obtain constraints on the neutron star radius (R=7.5+-1.0 km), the inclinat...
Lu, X.; Gridin, S.; Williams, R. T.; Mayhugh, M. R.; Gektin, A.; Syntfeld-Kazuch, A.; Swiderski, L.; Moszynski, M.
2017-01-01
Relatively recent experiments on the scintillation response of CsI:Tl have found that there are three main decay times of about 730 ns, 3 μ s , and 16 μ s , i.e., one more principal decay component than had been previously reported; that the pulse shape depends on gamma-ray energy; and that the proportionality curves of each decay component are different, with the energy-dependent light yield of the 16 -μ s component appearing to be anticorrelated with that of the 0.73 -μ s component at room temperature. These observations can be explained by the described model of carrier transport and recombination in a particle track. This model takes into account processes of hot and thermalized carrier diffusion, electric-field transport, trapping, nonlinear quenching, and radiative recombination. With one parameter set, the model reproduces multiple observables of CsI:Tl scintillation response, including the pulse shape with rise and three decay components, its energy dependence, the approximate proportionality, and the main trends in proportionality of different decay components. The model offers insights on the spatial and temporal distributions of carriers and their reactions in the track.
Remark on: the neutron spherical optical-model absorption.
Smith, A. B.; Nuclear Engineering Division
2007-06-30
The energy-dependent behavior of the absorption term of the spherical neutron optical potential for doubly magic {sup 208}Pb and the neighboring {sup 209}Bi is examined. These considerations suggest a phenomenological model that results in an intuitively attractive energy dependence of the imaginary potential that provides a good description of the observed neutron cross sections and that is qualitatively consistent with theoretical concepts. At the same time it provides an alternative to some of the arbitrary assumptions involved in many conventional optical-model interpretations reported in the literature and reduces the number of the parameters of the model.
Energy-dependent collective excitations in Os and Pt isotopes
Budaca, A. I.; Budaca, R.
2017-08-01
An exactly solvable model is constructed by considering an energy-dependent harmonic oscillator potential in the β part of the Bohr Hamiltonian separated adiabatically from the γ-angular degrees of freedom. The energy dependence is linear and introduced in the string constant. The fundamental implications of the energy dependence in quantum theory are thoroughly discussed in connection with the slope parameter. The numerical applications of the model are found to match the collective features for extended chains of even-even Os and Pt isotopes, which exhibit a smooth evolution in the slope of the energy dependence.
Linear representation of energy-dependent Hamiltonians
Znojil, Miloslav
2004-05-01
Quantum mechanics abounds in models with Hamiltonian operators which are energy-dependent. A linearization of the underlying Schrödinger equation with H= H( E) is proposed here via an introduction of a doublet of separate energy-independent representatives K and L of the respective right and left action of H( E). Both these new operators are non-Hermitian so that our formalism admits a natural extension to non-Hermitian initial H( E)s. Its applicability may range from pragmatic phenomenology and variational calculations (where all the subspace-projected effective operators depend on energy by construction) up to perturbation theory and quasi-exact constructions.
Particle-Hole Optical Model: Fantasy or Reality?
Urin, M H
2010-01-01
An attempt to formulate the optical model of particle-hole-type excitations (including giant resonances) is undertaken. The model is based on the Bethe--Goldstone equation for the particle-hole Green function. This equation involves a specific energy-dependent particle-hole interaction that is due to virtual excitation of many-quasiparticle configurations and responsible for the spreading effect. After energy averaging, this interaction involves an imaginary part. The analogy between the single-quasiparticle and particle-hole optical models is outlined.
A model for the energy-dependent time-lag and rms of the heartbeat oscillations in GRS 1915+105
Mir, Mubashir Hamid; Pahari, Mayukh; Iqbal, Naseer; Ahmad, Naveel
2016-01-01
Energy dependent phase lags reveal crucial information about the causal relation between various spectral components and about the nature of the accretion geometry around the compact objects. The time-lag and the fractional root mean square (rms) spectra of GRS 1915+105 in its heartbeat oscillation class/$\\rho$ state show peculiar behaviour at the fundamental and harmonic frequencies where the lags at the fundamental show a turn around at $\\sim$ 10 keV while the lags at the harmonic do not show any turn around at least till $\\sim$ 20 keV. The magnitude of lags are of the order of few seconds and hence cannot be attributed to the light travel time effects or Comptonization delays. The continuum X-ray spectra can roughly be described by a disk blackbody and a hard X-ray power-law component and from phase resolved spectroscopy it has been shown that the inner disk radius varies during the oscillation. Here, we propose that there is a delayed response of the inner disk radius (DROID) to the accretion rate such th...
Energy Dependence of the Intermodule Widening Correction
Mcblane, Neil Fraser
2017-01-01
This project looked to investigate the energy dependence of the ATLAS Liquid Argon (LAr) Calorimeter Intermodule Widening correction factors. A clear energy dependence was observed, with possible parameterisations of the dependency were briefly explored. In addition, official correction factors were validated on a new software release.
Tomic, Nada, E-mail: ntomic@roc.jgh.mcgill.ca; Quintero, Chrystian; Aldelaijan, Saad; Bekerat, Hamed; Liang, LiHeng; DeBlois, François; Devic, Slobodan [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4, Canada and Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montréal, Québec H3T 1E2 (Canada); Whiting, Bruce R. [Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 (United States); Seuntjens, Jan [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4 (Canada)
2014-06-15
Purpose: The authors investigated the energy response of XR-QA2 GafChromic{sup TM} film over a broad energy range used in diagnostic radiology examinations. The authors also made an assessment of the most suitable functions for both reference and relative dose measurements. Methods: Pieces of XR-QA2 film were irradiated to nine different values of air kerma in air, following reference calibration of a number of beam qualities ranging in HVLs from 0.16 to 8.25 mm Al, which corresponds to effective energy range from 12.7 keV to 56.3 keV. For each beam quality, the authors tested three functional forms (rational, linear exponential, and power) to assess the most suitable function by fitting the delivered air kerma in air as a function of film response in terms of reflectance change. The authors also introduced and tested a new parameterχ = netΔR·e{sup m} {sup netΔR} that linearizes the inherently nonlinear response of the film. Results: The authors have found that in the energy range investigated, the response of the XR-QA2 based radiochromic film dosimetry system ranges from 0.222 to 0.420 in terms of netΔR at K{sub air}{sup air} = 8 cGy. For beam qualities commonly used in CT scanners (4.03–8.25 mm Al), the variation in film response (netΔR at K{sub air}{sup air} = 8 cGy) amounts to ± 5%, while variation in K{sub air}{sup air} amounts to ± 14%. Conclusions: Results of our investigation revealed that the use of XR-QA2 GafChromic{sup TM} film is accompanied by a rather pronounced energy dependent response for beam qualities used for x-ray based diagnostic imaging purposes. The authors also found that the most appropriate function for the reference radiochromic film dosimetry would be the power function, while for the relative dosimetry one may use the exponential response function that can be easily linearized.
Le Roux, J. A.; Potgieter, M. S.
1992-01-01
Time-dependent heliospheric cosmic-ray modulation for the period 1985-1989 is simulated by means of a time-dependent axially symmetric drift model with an emulated wavy heliospheric neutral sheet (HNS). The model is used to extend previous calculations to other energies in order to study a possible energy-dependence of the onset of new modulation at various radial distances in 1987. The model, with the outward propagating changes of the HNS as the only time-dependent parameters, is found to predict essentially no energy-dependence in the time when new modulation started in the simulated 1987. When a more practical approach in defining 'constant' modulation in 1987 is followed, the present calculations can be interpreted to indicate that the end of the recovery period in 1987 happened progressively earlier and the onset of new modulation progressively later the higher the rigidity of the cosmic rays. This period of relatively unchanged modulation is predicted to last longer with increasing radial distance.
Energy Dependence of String Fragmentation Function and φ Meson Production
SA Ben-Hao; CAI Xu; Chinorat Kobdaj; WANG Zhong-Qi; YAN Yu-Peng; ZHOU Dai-Mei
2004-01-01
The φ meson productions in A u+A u and/or P b+Pb collisions at AGS, SPS, RHIC, and LHC energies have been studied systematically with a hadron and string cascade model LUCIAE.After considering the energy dependence of the model parameter α in string fragmentation function and adjusting it to the experimental data of charged multiplicity to a certain extent, the model predictions for φ meson yield, rapidity, and transverse mass distributions are compatible with the experimental data at AGS, SPS and RHIC energies. A calculation for Pb+Pb collisions at LHC energy is given as well. The obtained fractional variable in string fragmentation function shows a saturation in energy dependence. It is discussed that the saturation of fractional variable in string fragmentation function might be a qualitative representation of the energy dependence of nuclear transparency.
Models of optical quantum computing
Krovi Hari
2017-03-01
Full Text Available I review some work on models of quantum computing, optical implementations of these models, as well as the associated computational power. In particular, we discuss the circuit model and cluster state implementations using quantum optics with various encodings such as dual rail encoding, Gottesman-Kitaev-Preskill encoding, and coherent state encoding. Then we discuss intermediate models of optical computing such as boson sampling and its variants. Finally, we review some recent work in optical implementations of adiabatic quantum computing and analog optical computing. We also provide a brief description of the relevant aspects from complexity theory needed to understand the results surveyed.
Modeling of semiconductor optical amplifiers
Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther
We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....
Energy-dependent variability from accretion flows
Zdziarski, Andrzej A.
2005-01-01
We develop a formalism to calculate energy-dependent fractional variability (rms) in accretion flows. We consider rms spectra resulting from radial dependencies of the level of local variability (as expected from propagation of disturbances in accretion flows) assuming the constant shape of the spectrum emitted at a given radius. We consider the cases when the variability of the flow is either coherent or incoherent between different radial zones. As example local emission, we consider blackb...
Proton energy dependence of slow neutron intensity
Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ooi, Motoki [Hokkaido Univ., Sapporo (Japan)
2001-03-01
The choice of the proton energy is an important issue for the design of an intense-pulsed-spallation source. The optimal proton beam energy is rather unique from a viewpoint of the leakage neutron intensity but no yet clear from the slow-neutron intensity view point. It also depends on an accelerator type. Since it is also important to know the proton energy dependence of slow-neutrons from the moderators in a realistic target-moderator-reflector assembly (TMRA). We studied on the TMRA proposed for Japan Spallation Neutron Source. The slow-neutron intensities from the moderators per unit proton beam power (MW) exhibit the maximum at about 1-2 GeV. At higher proton energies the intensity per MW goes down; at 3 and 50 GeV about 0.91 and 0.47 times as low as that at 1 GeV. The proton energy dependence of slow-neutron intensities was found to be almost the same as that of total neutron yield (leakage neutrons) from the same bare target. It was also found that proton energy dependence was almost the same for the coupled and decoupled moderators, regardless the different moderator type, geometry and coupling scheme. (author)
Energy Dependence of Multiplicity Fluctuations in Heavy Ion Collisions
Lungwitz, B; Anticic, T; Baatar, B; Barna, D; Bartke, J; Betev, L; Białkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chung, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flier, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Ga´zdzicki, M; Genchev, V; Georgopoulos, G; Gładysz, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kikola, D; Kliemant, M; Kniege, S; Kolesnikov, V I; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Laszlo, A; Lacey, R; Van Leeuwen, M; Lévai, Peter; Litov, L; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Peryt, W; Pikna, M; Pluta, J; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Slodkowski, M; Stefanek, G; Stock, R; Strabel, C; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Szuba, M; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Włodarczyk, Z; Wojtaszek, A; Yoo, I K; Zimányi, J; Lungwitz, Benjamin
2006-01-01
The energy dependence of multiplicity fluctuations was studied for the most central $Pb+Pb$ collisions at $20A$, $30A$, $40A$, $80A$ and $158A$ GeV by the NA49 experiment at the CERN SPS. The multiplicity distribution for negatively and positively charged hadrons is significantly narrower than Poisson one for all energies. No significant structure in energy dependence of the scaled variance of multiplicity fluctuations is observed. The measured scaled variance is lower than the one predicted by the grand-canonical formulation of the hadron-resonance gas model. The results for scaled variance are in approximate agreement with the string-hadronic model UrQMD.
Optical-Microphysical Cirrus Model
Reichardt, J.; Reichardt, S.; Lin, R.-F.; Hess, M.; McGee, T. J.; Starr, D. O.
2008-01-01
A model is presented that permits the simulation of the optical properties of cirrus clouds as measured with depolarization Raman lidars. It comprises a one-dimensional cirrus model with explicit microphysics and an optical module that transforms the microphysical model output to cloud and particle optical properties. The optical model takes into account scattering by randomly oriented or horizontally aligned planar and columnar monocrystals and polycrystals. Key cloud properties such as the fraction of plate-like particles and the number of basic crystals per polycrystal are parameterized in terms of the ambient temperature, the nucleation temperature, or the mass of the particles. The optical-microphysical model is used to simulate the lidar measurement of a synoptically forced cirrostratus in a first case study. It turns out that a cirrus cloud consisting of only monocrystals in random orientation is too simple a model scenario to explain the observations. However, good agreement between simulation and observation is reached when the formation of polycrystals or the horizontal alignment of monocrystals is permitted. Moreover, the model results show that plate fraction and morphological complexity are best parameterized in terms of particle mass, or ambient temperature which indicates that the ambient conditions affect cirrus optical properties more than those during particle formation. Furthermore, the modeled profiles of particle shape and size are in excellent agreement with in situ and laboratory studies, i.e., (partly oriented) polycrystalline particles with mainly planar basic crystals in the cloud bottom layer, and monocrystals above, with the fraction of columns increasing and the shape and size of the particles changing from large thin plates and long columns to small, more isometric crystals from cloud center to top. The findings of this case study corroborate the microphysical interpretation of cirrus measurements with lidar as suggested previously.
Performance modeling of optical refrigerators
Mills, G.; Mord, A. [Ball Aerospace and Technologies Corp., Boulder, CO (United States). Cryogenic and Thermal Engineering
2006-02-15
Optical refrigeration using anti-Stokes fluorescence in solids has several advantages over more conventional techniques including low mass, low volume, low cost and no vibration. It also has the potential of allowing miniature cryocoolers on the scale of a few cubic centimeters. It has been the topic of analysis and experimental work by several organizations. In 2003, we demonstrated the first optical refrigerator. We have developed a comprehensive system-level performance model of optical refrigerators. Our current version models the refrigeration cycle based on the fluorescent material emission and absorption data at ambient and reduced temperature for the Ytterbium-ZBLAN glass (Yb:ZBLAN) cooling material. It also includes the heat transfer into the refrigerator cooling assembly due to radiation and conduction. In this paper, we report on modeling results which reveal the interplay between size, power input, and cooling load. This interplay results in practical size limitations using Yb:ZBLAN. (author)
Optical Coherence Tomography: Advanced Modeling
Andersen, Peter E.; Thrane, Lars; Yura, Harold T.;
2013-01-01
Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens-Fresnel principle valid both for the single......- and multiple-scattering regimes is derived. An advanced Monte Carlo model for calculating the OCT signal is also derived, and the validity of this model is shown through a mathematical proof based on the extended Huygens-Fresnel principle. From the analytical model, an algorithm for enhancing OCT images...... is developed, the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. The algorithm is verified experimentally and by using the Monte Carlo model as a numerical tissue phantom. Applications of extraction of optical properties from tissue...
Experimental energy-dependent nuclear spin distributions
Egidy, Till von [Physik-Department, T.U. Muenchen (Germany); Bucurescu, Dorel [National Inst. Phys. and Nucl. Eng., Bucharest (Romania)
2010-07-01
A new method is proposed to determine the energy dependent spin distribution in experimental nuclear level schemes. This method compares various experimental and calculated moments in the energy-spin plane in order to obtain the spin-cutoff parameter {sigma} as a function of mass A and excitation energy using a total of 7202 levels with spin assignment in 227 nuclei between F and Cf. A simple formula, {sigma}{sup 2}=0.391 . A{sup 0.675}(E-0.5 .Pa'){sup 0.312}, is proposed up to about 10 MeV which is in very good agreement with experimental {sigma} values and is applied to improve the systematics of level density parameters.
Energy-dependent variability from accretion flows
Zdziarski, A A
2005-01-01
We develop a formalism to calculate energy-dependent fractional variability (rms) in accretion flows. We consider rms spectra resulting from radial dependencies of the level of local variability (as expected from propagation of disturbances in accretion flows) assuming the constant shape of the spectrum emitted at a given radius. We consider the cases when the variability of the flow is either coherent or incoherent between different radial zones. As example local emission, we consider blackbody, Wien and thermal Comptonization spectra. In addition to numerical results, we present a number of analytical formulae for the resulting rms. We also find an analytical formula for the disc Wien spectrum, which we find to be a very good approximation to the disc blackbody. We compare our results to the rms spectrum observed in an ultrasoft state of GRS 1915+105.
Socio-optics: optical knowledge applied in modeling social phenomena
Chisleag, Radu; Chisleag Losada, Ioana-Roxana
2011-05-01
The term "Socio-optics" (as a natural part of Socio-physics), is rather not found in literature or at Congresses. In Optics books, there are not made references to optical models applied to explain social phenomena, in spite of Optics relying on the duality particle-wave which seems convenient to model relationships among society and its members. The authors, who have developed a few models applied to explain social phenomena based on knowledge in Optics, along with a few other models applying, in Social Sciences, knowledge from other branches of Physics, give their own examples of such optical models, f. e., of relationships among social groups and their sub-groups, by using kowledge from partially coherent optical phenomena or to explain by tunnel effect, the apparently impossible penetration of social barriers by individuals. They consider that the term "Socio-optics" may come to life. There is mentioned the authors' expertise in stimulating Socio-optics approach by systematically asking students taken courses in Optics to find applications of the newly got Wave and Photon Optics knowledge, to model social and even everyday life phenomena, eventually engaging in such activities other possibly interested colleagues.
Nuclear mean field and double-folding model of the nucleus-nucleus optical potential
Khoa, Dao T; Loan, Doan Thi; Loc, Bui Minh
2016-01-01
Realistic density dependent CDM3Yn versions of the M3Y interaction have been used in an extended Hartree-Fock (HF) calculation of nuclear matter (NM), with the nucleon single-particle potential determined from the total NM energy based on the Hugenholtz-van Hove theorem that gives rise naturally to a rearrangement term (RT). Using the RT of the single-nucleon potential obtained exactly at different NM densities, the density- and energy dependence of the CDM3Yn interactions was modified to account properly for both the RT and observed energy dependence of the nucleon optical potential. Based on a local density approximation, the double-folding model of the nucleus-nucleus optical potential has been extended to take into account consistently the rearrangement effect and energy dependence of the nuclear mean-field potential, using the modified CDM3Yn interactions. The extended double-folding model was applied to study the elastic $^{12}$C+$^{12}$C and $^{16}$O+$^{12}$C scattering at the refractive energies, wher...
Novel applications of the dispersive optical model
Dickhoff, W. H.; Charity, R. J.; Mahzoon, M. H.
2017-03-01
A review of recent developments of the dispersive optical model (DOM) is presented. Starting from the original work of Mahaux and Sartor, several necessary steps are developed and illustrated which increase the scope of the DOM allowing its interpretation as generating an experimentally constrained functional form of the nucleon self-energy. The method could therefore be renamed as the dispersive self-energy method. The aforementioned steps include the introduction of simultaneous fits of data for chains of isotopes or isotones allowing a data-driven extrapolation for the prediction of scattering cross sections and level properties in the direction of the respective drip lines. In addition, the energy domain for data was enlarged to include results up to 200 MeV where available. An important application of this work was implemented by employing these DOM potentials to the analysis of the (d, p) transfer reaction using the adiabatic distorted wave approximation. We review these calculations which suggest that physically meaningful results are easier to obtain by employing DOM ingredients as compared to the traditional approach which relies on a phenomenologically-adjusted bound-state wave function combined with a global (nondispersive) optical-model potential. Application to the exotic 132Sn nucleus also shows great promise for the extrapolation of DOM potentials towards the drip line with attendant relevance for the physics of FRIB. We note that the DOM method combines structure and reaction information on the same footing providing a unique approach to the analysis of exotic nuclei. We illustrate the importance of abandoning the custom of representing the non-local Hartree–Fock (HF) potential in the DOM by an energy-dependent local potential as it impedes the proper normalization of the solution of the Dyson equation. This important step allows for the interpretation of the DOM potential as representing the nucleon self-energy permitting the calculations of
Microscopic Optical Potential of α-Nucleus Elastic Scattering
2008-01-01
<正>The nucleon microscopic optical model potentials (OMP) in the nuclear medium are studied in the framework of the Dirac-Brueckner-Hartree-Fock approach, which are of density- and energy-dependence.
Optical models of the molecular atmosphere
Zuev, V. E.; Makushkin, Y. S.; Mitsel, A. A.; Ponomarev, Y. N.; Rudenko, V. P.; Firsov, K. M.
1986-01-01
The use of optical and laser methods for performing atmospheric investigations has stimulated the development of the optical models of the atmosphere. The principles of constructing the optical models of molecular atmosphere for radiation with different spectral composition (wideband, narrowband, and monochromatic) are considered in the case of linear and nonlinear absorptions. The example of the development of a system which provides for the modeling of the processes of optical-wave energy transfer in the atmosphere is presented. Its physical foundations, structure, programming software, and functioning were considered.
Separation energy dependence of hole form factors
Van de Wiele, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Vdovin, A. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Langevin-Joliot, H. [Institut de Physique Nucleaire, 91 - Orsay (France)
1996-08-05
Form factors of fragmented hole states are studied within the quasiparticle-phonon model, using the inhomogeneous equation method. The validity of this method is successfully checked by comparison with coupled equation solutions in schematic vibrational model cases. A systematic investigation of form factors is performed for neutron and proton hole states in the valence and first inner shells of {sup 208}Pb. Large fluctuations of form factor radii are observed for individual levels superimposed on a general increase with separation energy. Average characteristics are introduced for groups of levels, namely the mean form factors, summed source terms and correction potentials, and their behaviour is presented. The role of the relative values of the interaction radius parameter and binding well radius is discussed in detail. (orig.).
Separation energy dependence of hole form factors
Van de Wiele, J.; Langevin-Joliot, H. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Vdovin, A. [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Bogoliubov Lab. of Theoretical Physics
1996-04-01
Form factors of fragmented hole states are studied within the quasiparticle-phonon model, using the inhomogeneous equation method. A systematic investigation of form factors is performed for neutron and proton hole states in the valence and first inner shells of {sup 208}Pb. Average characteristics are introduced for groups of levels, namely the mean form factors, summed source terms and correction potentials, and their behaviour is presented. The role of the relative values of the interaction radius parameter and binding well radius is discussed in details. (K.A.). 21 refs.; Submitted to Elsevier Science.
The Folding Deuteron Optical Model Potentials
Li, Xiaohua; Cai, Chonghai
2008-01-01
For 52 target nuclei with deuteron as projectile, we calculate the reaction cross sections and elastic scattering angular distributions, as well as the $\\chi^2$ values for 11 kinds of deuteron optical model potentials: our global deuteron optical potentials and 10 folding optical potentials calculated with 2 phenomenological global nucleon optical potentials given by Koning \\textit{et al}(KD) and by Varner\\textit{et al}(CH89), and 8 microscopic nucleon optical potentials with the generalized Skyrme force parameters(GS1-6) and modified Skyrme force parameters(SKa, SKb). We find that for constructing the folding deuteron optical potential, both SKa and SKb are the best Skyrme force parameters of the microscopic nucleon optical potential proposed by Q. Shen \\textit{et al}.
Energy-dependent relative charge transfer cross sections of Cs+ + Rb(5s, 5p)
Nguyen, H; Fléchard, X; DePaola, B D
2013-01-01
Magneto optical trap recoil ion momentum spectroscopy is used to measure energy-dependent charge exchange cross sections in the Cs+ + Rb(5s, 5p) system over a range of projectile energies from 3.2 to 6.4 keV. The measurements are kinematically complete and yield cross sections that are differential in collision energy, scattering angle, and initial and final states.
Optical Hall effect-model description: tutorial.
Schubert, Mathias; Kühne, Philipp; Darakchieva, Vanya; Hofmann, Tino
2016-08-01
The optical Hall effect is a physical phenomenon that describes the occurrence of magnetic-field-induced dielectric displacement at optical wavelengths, transverse and longitudinal to the incident electric field, and analogous to the static electrical Hall effect. The electrical Hall effect and certain cases of the optical Hall effect observations can be explained by extensions of the classic Drude model for the transport of electrons in metals. The optical Hall effect is most useful for characterization of electrical properties in semiconductors. Among many advantages, while the optical Hall effect dispenses with the need of electrical contacts, electrical material properties such as effective mass and mobility parameters, including their anisotropy as well as carrier type and density, can be determined from the optical Hall effect. Measurement of the optical Hall effect can be performed within the concept of generalized ellipsometry at an oblique angle of incidence. In this paper, we review and discuss physical model equations, which can be used to calculate the optical Hall effect in single- and multiple-layered structures of semiconductor materials. We define the optical Hall effect dielectric function tensor, demonstrate diagonalization approaches, and show requirements for the optical Hall effect tensor from energy conservation. We discuss both continuum and quantum approaches, and we provide a brief description of the generalized ellipsometry concept, the Mueller matrix calculus, and a 4×4 matrix algebra to calculate data accessible by experiment. In a follow-up paper, we will discuss strategies and approaches for experimental data acquisition and analysis.
Inelastic cotunneling with energy-dependent contact transmission
Blok, S.; Agundez Mojarro, R. R.; Maduro, L. A.; Blaauboer, M.; Van Der Molen, S. J.
2017-03-01
We investigate inelastic cotunneling in a model system where the charging island is connected to the leads through molecules with energy-dependent transmission functions. To study this problem, we propose two different approaches. The first is a pragmatic approach that assumes Lorentzian-like transmission functions that determine the transmission probability to the island. Using this model, we calculate current versus voltage (IV) curves for increasing resonance level positions of the molecule. We find that shifting the resonance energy of the molecule away from the Fermi energy of the contacts leads to a decreased current at low bias, but as bias increases, this difference decreases and eventually inverses. This is markedly different from IV behavior outside the cotunneling regime. The second approach involves multiple cotunneling where also the molecules are considered to be in the Coulomb blockade regime. We find here that when Ec≫eV ,kBT , the IV behavior approaches the original cotunneling behavior proposed by Averin and Nazarov [Phys. Rev. Lett. 65, 2446-2449 (1990)].
Energy-Dependent Timing of Thermal Emission in Solar Flares
Jain, Rajmal; Rajpurohit, Arvind Singh; Aschwanden, Markus J; 10.1007/s11207-011-9754-1
2011-01-01
We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si detector of the "Solar X-ray Spectrometer" (SOXS). The SOXS onboard the Indian GSAT-2 spacecraft was launched by the GSLV-D2 rocket on 8 May 2003. Firstly we model the spectral evolution of the X-ray line and continuum emission flux F(\\epsilon) from the flare by integrating a series of isothermal plasma flux. We find that multi-temperature integrated flux F(\\epsilon) is a power-law function of \\epsilon with a spectral index (\\gamma) \\approx -4.65. Next, based on spectral-temporal evolution of the flares we find that the emission in the energy range E= 4 - 15 keV is dominated by temperatures of T= 12 - 50 MK, while the multi-thermal power-law DEM index (\\gamma) varies in the range of -4.4 and -5.7. The temporal evolution of the X-ray flux F(\\epsilon,t) assuming a multi-temperature ...
Model of computation for Fourier optical processors
Naughton, Thomas J.
2000-05-01
We present a novel and simple theoretical model of computation that captures what we believe are the most important characteristics of an optical Fourier transform processor. We use this abstract model to reason about the computational properties of the physical systems it describes. We define a grammar for our model's instruction language, and use it to write algorithms for well-known filtering and correlation techniques. We also suggest suitable computational complexity measures that could be used to analyze any coherent optical information processing technique, described with the language, for efficiency. Our choice of instruction language allows us to argue that algorithms describable with this model should have optical implementations that do not require a digital electronic computer to act as a master unit. Through simulation of a well known model of computation from computer theory we investigate the general-purpose capabilities of analog optical processors.
Energy Dependence of the Lambda-Sigma0 Production in Proton-Proton Collisions
Dillig, M
2006-01-01
The energy dependence of the reactions pp -> p Lambda K+ and pp -> p Sigma0 K+ and the ratio R(Lambda/Sigma0} is studied in a constituent quark-gluon model, including the excitation of the baryon resonances N*(1650), N*(1710) and N*(1720) near the Lambda/Sigma0 thresholds. Representing the baryons as quark-diquark objects, the energy dependent ratio Lambda/Sigma0, which is qualitatively reproduced up to excess energies of 60 MeV above threshold, provides detailed information on the momentum spectrum of axial diquarks in the proton and the Sigma0.
Energy-Dependent Fission Q Values Generalized for All Actinides
Vogt, R
2008-09-25
We generalize Madland's parameterization of the energy release in fission to obtain the dependence of the fission Q values on incident neutron energy, E{sub n}, for all major and minor actinides. These Q(E{sub n}) parameterizations are included in the ENDL2008 release. This paper describes calculations of energy-dependent fission Q values based on parameterizations of the prompt energy release in fission [1], developed by Madland [1] to describe the prompt energy release in neutron-induced fission of {sup 235}U, {sup 238}U, and {sup 239}Pu. The energy release is then related to the energy deposited during fission so that experimentally measurable quantities can be used to obtain the Q values. A discussion of these specific parameterizations and their implementation in the processing code for Monte Carlo neutron transport, MCFGEN, [2] is described in Ref. [3]. We extend this model to describe Q(E) for all actinides, major and minor, in the Evaluated Nuclear Data Library (ENDL) 2008 release, ENDL2008.
Energy dependence evaluation of the patient dose calibrator
Costa, N. A.; Potiens, M. P. A.
2014-02-01
The aim of this paper was to evaluate the energy dependence of the kerma-area product meter Patient Dose Calibrator (PDC). The research was done using the calculation of the coefficient calibration of the air kerma values of different energies that are related to the radiation qualities provided on the International Standard of the International Electrotechnical Commission IEC 61267 for conventional X-rays, mammography and computerized tomography (CT), established at the Calibration Laboratory of IPEN. The calibration was made using reference ionization chambers with traceability to the Primary Laboratory Physikalisch-Technische Bundesanstalt (PTB), Germany. The energy dependence of the PDC was determined and the results showed that the PDC has small energy dependence, less than 6%, for the range of recommended energy while to the mammography range the values were 16% and for CT qualities the dependence was 1%.
Optical model calculation for the unresolved/resolved resonance region of Fe-56
Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Froehner, F.H.
1997-03-01
We have studied optical model fits to total neutron cross sections of structural materials using the accurate data base for {sup 56}Fe existing in the resolved and unresolved resonance region. Averages over resolved resonances were calculated with Lorentzian weighting in Reich-Moore (reduced R matrix) approximation. Starting from the best available optical potentials we found that adjustment of the real and imaginary well depths does not work satisfactorily with the conventional weak linear energy dependence of the well depths. If, however, the linear dependences are modified towards low energies, the average total cross sections can be fitted quite well, from the resolved resonance region up to 20 MeV and higher. (author)
Quesada, José Manuel; Capote, Roberto; Soukhovitski, Efrem S.; Chiba, Satoshi
2016-03-01
An extension for odd-A actinides of a previously derived dispersive coupledchannel optical model potential (OMP) for 238U and 232Th nuclei is presented. It is used to fit simultaneously all the available experimental databases including neutron strength functions for nucleon scattering on 232Th, 233,235,238U and 239Pu nuclei. Quasi-elastic (p,n) scattering data on 232Th and 238U to the isobaric analogue states of the target nucleus are also used to constrain the isovector part of the optical potential. For even-even (odd) actinides almost all low-lying collective levels below 1 MeV (0.5 MeV) of excitation energy are coupled. OMP parameters show a smooth energy dependence and energy independent geometry.
Modeling and optimization of LCD optical performance
Yakovlev, Dmitry A; Kwok, Hoi-Sing
2015-01-01
The aim of this book is to present the theoretical foundations of modeling the optical characteristics of liquid crystal displays, critically reviewing modern modeling methods and examining areas of applicability. The modern matrix formalisms of optics of anisotropic stratified media, most convenient for solving problems of numerical modeling and optimization of LCD, will be considered in detail. The benefits of combined use of the matrix methods will be shown, which generally provides the best compromise between physical adequacy and accuracy with computational efficiency and optimization fac
Yan, Yun-An, E-mail: yunan@gznc.edu.cn [Guizhou Provincial Key Laboratory of Computational Nanomaterial Science, Guizhou Education University, Guiyang, Guizhou 550018 (China)
2016-01-14
The quantum interference is an intrinsic phenomenon in quantum physics for photon and massive quantum particles. In principle, the quantum interference may also occur with quasi-particles, such as the exciton. In this study, we show how the exciton quantum interference can be significant in aggregates through theoretical simulations with hierarchical equations of motion. The systems under investigation are generalized donor-bridge-acceptor model aggregates with the donor consisting of six homogeneous sites assuming the nearest neighbor coupling. For the models with single-path bridge, the exciton transfer time only shows a weak excitation energy dependence. But models with double-path bridge have a new short transfer time scale and the excitation energy dependence of the exciton transfer time assumes clear peak structure which is detectable with today’s nonlinear spectroscopy. This abnormality is attributed to the exciton quantum interference and the condition for a clear observation in experiment is also explored.
An efficient method for evaluating energy-dependent sum rules
Dinur, Nir Nevo; Bacca, Sonia; Barnea, Nir
2014-01-01
Energy-dependent sum rules are useful tools in many fields of physics. In nuclear physics, they typically involve an integration of the response function over the nuclear spectrum with a weight function composed of integer powers of the energy. More complicated weight functions are also encountered, e.g., in nuclear polarization corrections of atomic spectra. Using the Lorentz integral transform method and the Lanczos algorithm, we derive a computationally efficient technique for evaluating such sum rules that avoids the explicit calculation of both the continuum states and the response function itself. Our numerical results for electric dipole sum rules of the Helium-4 nucleus with various energy-dependent weights show rapid convergence with respect to the number of Lanczos steps. This demonstrates the usefulness of the method in a variety of electroweak reactions.
Normalization of energy-dependent gamma survey data.
Whicker, Randy; Chambers, Douglas
2015-05-01
Instruments and methods for normalization of energy-dependent gamma radiation survey data to a less energy-dependent basis of measurement are evaluated based on relevant field data collected at 15 different sites across the western United States along with a site in Mongolia. Normalization performance is assessed relative to measurements with a high-pressure ionization chamber (HPIC) due to its "flat" energy response and accurate measurement of the true exposure rate from both cosmic and terrestrial radiation. While analytically ideal for normalization applications, cost and practicality disadvantages have increased demand for alternatives to the HPIC. Regression analysis on paired measurements between energy-dependent sodium iodide (NaI) scintillation detectors (5-cm by 5-cm crystal dimensions) and the HPIC revealed highly consistent relationships among sites not previously impacted by radiological contamination (natural sites). A resulting generalized data normalization factor based on the average sensitivity of NaI detectors to naturally occurring terrestrial radiation (0.56 nGy hHPIC per nGy hNaI), combined with the calculated site-specific estimate of cosmic radiation, produced reasonably accurate predictions of HPIC readings at natural sites. Normalization against two to potential alternative instruments (a tissue-equivalent plastic scintillator and energy-compensated NaI detector) did not perform better than the sensitivity adjustment approach at natural sites. Each approach produced unreliable estimates of HPIC readings at radiologically impacted sites, though normalization against the plastic scintillator or energy-compensated NaI detector can address incompatibilities between different energy-dependent instruments with respect to estimation of soil radionuclide levels. The appropriate data normalization method depends on the nature of the site, expected duration of the project, survey objectives, and considerations of cost and practicality.
Energy dependence of polymer gels in the orthovoltage energy range
Yvonne Roed
2014-03-01
Full Text Available Purpose: Ortho-voltage energies are often used for treatment of patients’ superficial lesions, and also for small- animal irradiations. Polymer-Gel dosimeters such as MAGAT (Methacrylic acid Gel and THPC are finding increasing use for 3-dimensional verification of radiation doses in a given treatment geometry. For mega-voltage beams, energy dependence of MAGAT has been quoted as nearly energy-independent. In the kilo-voltage range, there is hardly any literature to shade light on its energy dependence.Methods: MAGAT was used to measure depth-dose for 250 kVp beam. Comparison with ion-chamber data showed a discrepancy increasing significantly with depth. An over-response as much as 25% was observed at a depth of 6 cm.Results and Conclusion: Investigation concluded that 6 cm water in the beam resulted in a half-value-layer (HVL change from 1.05 to 1.32 mm Cu. This amounts to an effective-energy change from 81.3 to 89.5 keV. Response measurements of MAGAT at these two energies explained the observed discrepancy in depth-dose measurements. Dose-calibration curves of MAGAT for (i 250 kVp beam, and (ii 250 kVp beam through 6 cm of water column are presented showing significant energy dependence.-------------------Cite this article as: Roed Y, Tailor R, Pinksy L, Ibbott G. Energy dependence of polymer gels in the orthovoltage energy range. Int J Cancer Ther Oncol 2014; 2(2:020232. DOI: 10.14319/ijcto.0202.32
Bohr Hamiltonian with an energy dependent $\\gamma$-unstable Coulomb-like potential
Budaca, R
2016-01-01
An exact analytical solution for the Bohr Hamiltonian with an energy dependent Coulomb-like $\\gamma$-unstable potential is presented. Due to the linear energy dependence of the potential's coupling constant, the corresponding spectrum in the asymptotic limit of the slope parameter resembles the spectral structure of the spherical vibrator, however with a different state degeneracy. The parameter free energy spectrum as well as the transition rates for this case are given in closed form and duly compared with those of the harmonic $U(5)$ dynamical symmetry. The model wave functions are found to exhibit properties that can be associated to shape coexistence. A possible experimental realization of the model is found in few medium nuclei with a very low second $0^{+}$ state known to exhibit competing prolate, oblate and spherical shapes.
Bohr Hamiltonian with an energy-dependent γ-unstable Coulomb-like potential
Budaca, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)
2016-10-15
An exact analytical solution for the Bohr Hamiltonian with an energy-dependent Coulomb-like γ-unstable potential is presented. Due to the linear energy dependence of the potential's coupling constant, the corresponding spectrum in the asymptotic limit of the slope parameter resembles the spectral structure of the spherical vibrator, however with a different state degeneracy. The parameter free energy spectrum as well as the transition rates for this case are given in closed form and duly compared with those of the harmonic U(5) dynamical symmetry. The model wave functions are found to exhibit properties that can be associated to shape coexistence. A possible experimental realization of the model is found in few medium nuclei with a very low second 0{sup +} state known to exhibit competing prolate, oblate and spherical shapes. (orig.)
Completely integrable models of nonlinear optics
Andrey I Maimistov
2001-11-01
The models of the nonlinear optics in which solitons appeared are considered. These models are of paramount importance in studies of nonlinear wave phenomena. The classical examples of phenomena of this kind are the self-focusing, self-induced transparency and parametric interaction of three waves. At present there are a number of theories based on completely integrable systems of equations, which are, both, generations of the original known models and new ones. The modiﬁed Korteweg-de Vries equation, the nonlinear Schrödinger equation, the derivative nonlinear Schrödinger equation, Sine–Gordon equation, the reduced Maxwell–Bloch equation, Hirota equation, the principal chiral ﬁeld equations, and the equations of massive Thirring model are some soliton equations, which are usually to be found in nonlinear optics theory.
On the energy dependence of proton beam extraction with a bent crystal
Arduini, Gianluigi; Fidecaro, Giuseppe; Gyr, Marcel; Herr, Werner; Klem, J T; Mikkelsen, U; Weisse, E
1998-01-01
Proton beam extraction from the CERN SPS by means of a bent silicon crystal is reported at three different energies, 14 GeV, 120 GeV and 270 GeV. The experimental results are compared to computer simulations which contain a sound model of the SPS accelerator as well as the channeling phenomena in bent crystals. The overall energy dependence of crystal assisted proton beam extraction is understood and provides the basis to discuss such a scheme for future accelerators.
Optical models for silicon solar cells
Marshall, T.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)
1995-08-01
Light trapping is an important design feature for high-efficiency silicon solar cells. Because light trapping can considerably enhance optical absorption, a thinner substrate can be used which, in turn, can lower the bulk carrier recombination and concommitantly increase open-circuit voltage, and fill factor of the cell. The basic concepts of light trapping are similar to that of excitation of an optical waveguide, where a prism or a grating structure increases the phase velocity of the incoming optical wave such that waves propagated within the waveguide are totally reflected at the interfaces. Unfortunately, these concepts break down because the entire solar cell is covered with such a structure, making it necessary to develop new analytical approaches to deal with incomplete light trapping in solar cells. This paper describes two models that analyze light trapping in thick and thin solar cells.
Local and global nucleon optical models from 1 keV to 200 MeV
Köning, A J
2003-01-01
We present new phenomenological optical model potentials (OMPs) for neutrons and protons with incident energies from 1 keV up to 200 MeV, for (near-)spherical nuclides in the mass range 24<=A<=209. They are based on a smooth, unique functional form for the energy dependence of the potential depths, and on physically constrained geometry parameters. For the first time, this enables one to predict basic scattering observables over a broad mass range and over an energy range that covers several orders of magnitude in MeV. Thereby, the necessity of using different OMPs in different energy regions has been removed. Using extensive grid searches and a new computational steering technique, we have obtained optical model parameters for many isotopes separately. We recommend that the resulting, so-called local, optical models be used in theoretical analyses of nuclear data. From these parameterizations, we have also constructed asymmetry-dependent neutron and proton global OMPs that are superior to all other exi...
Advanced modelling of optical coherence tomography systems
Andersen, Peter E.; Thrane, L.; Yura, H.T.;
2004-01-01
Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens–Fresnel principle valid both for the single...... and multiple scattering regimes is reviewed. An advanced Monte Carlo model for calculating the OCT signal is also reviewed, and the validity of this model is shown through a mathematical proof based on the extended Huygens–Fresnel principle. Moreover, for the first time the model is verified experimentally....... From the analytical model, an algorithm for enhancing OCT images is developed; the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. For the first time, the algorithm is demonstrated by using the Monte Carlo model as a numerical...
RxGen General Optical Model Prescription Generator
Sigrist, Norbert
2012-01-01
RxGen is a prescription generator for JPL's in-house optical modeling software package called MACOS (Modeling and Analysis for Controlled Optical Systems), which is an expert optical analysis software package focusing on modeling optics on dynamic structures, deformable optics, and controlled optics. The objectives of RxGen are to simplify and automate MACOS prescription generations, reducing errors associated with creating such optical prescriptions, and improving user efficiency without requiring MACOS proficiency. RxGen uses MATLAB (a high-level language and interactive environment developed by MathWorks) as the development and deployment platform, but RxGen can easily be ported to another optical modeling/analysis platform. Running RxGen within the modeling environment has the huge benefit that variations in optical models can be made an integral part of the modeling state. For instance, optical prescription parameters determined as external functional dependencies, optical variations by controlling the in-/exclusion of optical components like sub-systems, and/or controlling the state of all components. Combining the mentioned capabilities and flexibilities with RxGen's optical abstraction layer completely eliminates the hindering aspects for requiring proficiency in writing/editing MACOS prescriptions, allowing users to focus on the modeling aspects of optical systems, i.e., increasing productivity and efficiency. RxGen provides significant enhancements to MACOS and delivers a framework for fast prototyping as well as for developing very complex controlled optical systems.
Energy dependent transport length scales in strongly diffusive carbon nanotubes
Lassagne, B [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Raquet, B [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Broto, J M [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Gonzalez, J [Centro de Estudios de Semiconductores Facultad de Ciencias, Departamento de Fisica, Universidad de Los Andes, Merida (Venezuela)
2006-05-17
We report magneto-transport measurements in parallel magnetic field and {mu}-Raman spectroscopy on diffusive multiwall carbon nanotubes. The disorder effects on the characteristic transport lengths are probed by combining applied magnetic field and back-gate tuning of the Fermi level. Modulations of the differential conductance versus energy depict the modulation of the strength of the weak localization. Both the electronic mean free path and the phase coherence length are found to be energy dependent. The role of disorder in the density of states and in the characteristic transport lengths is discussed.
Energy Dependence of Inclusive Spectra in $e^{+} e^{-}$ Annihilation
Abreu, P; Adye, T; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Beillière, P; Belokopytov, Yu A; Belous, K S; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschbeck, Brigitte; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Shlyapnikov, P; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Ferro, F; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, P S; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Laugier, J P; Lauhakangas, R; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Maltezos, S; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Nassiakou, M; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwering, B; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Chikilev, O G; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
1999-01-01
Inclusive charged hadron distributions as obtaind from the DELPHI measurements at 130, 136, 161, 172 and 183 GeV are presented as a function of the variables rapidity, $\\xi_p$, $p$ and transversal momenta. Data are compared with event generators and with MLLA calculations, in order to examine the hypothesis of local parton hadron duality. The differential momentum spectra show an indication for coherence effects in the production of soft particles. The relation between the energy dependence of the charged multiplicity and the rapidity distribution is examined.
Lü, X.; Schrottke, L.; Grahn, H. T. [Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V., Hausvogteiplatz 5–7, 10117 Berlin (Germany)
2016-06-07
We present scattering rates for electrons at longitudinal optical phonons within a model completely formulated in the Fourier domain. The total intersubband scattering rates are obtained by averaging over the intrasubband electron distributions. The rates consist of the Fourier components of the electron wave functions and a contribution depending only on the intersubband energies and the intrasubband carrier distributions. The energy-dependent part can be reproduced by a rational function, which allows for the separation of the scattering rates into a dipole-like contribution, an overlap-like contribution, and a contribution which can be neglected for low and intermediate carrier densities of the initial subband. For a balance between accuracy and computation time, the number of Fourier components can be adjusted. This approach facilitates an efficient design of complex heterostructures with realistic, temperature- and carrier density-dependent rates.
Dispersive spherical optical model of neutron scattering from Al27 up to 250 MeV
Molina, A; Quesada, J M; Lozano, M
2002-01-01
A spherical optical model potential (OMP) containing a dispersive term is used to fit the available experimental database of angular distribution and total cross section data for n + Al27 covering the energy range 0.1- 250 MeV using relativistic kinematics and a relativistic extension of the Schroedinger equation. A dispersive OMP with parameters that show a smooth energy dependence and energy independent geometry are determined from fits to the entire data set. A very good overall agreement between experimental data and predictions is achieved up to 150 MeV. Inclusion of nonlocality effects in the absorptive volume potential allows to achieve an excellent agreement up to 250 MeV.
Aznar, M.C.; Medin, J.; Hemdal, B.
2005-01-01
large energy dependence in low-energy X-ray beams can be expected. In the present work, the energy dependence of Al2O3:C crystals was modelled with the Monte Carlo code EGSnre using three types of X-ray spectra. The results obtained (5.6-7.3%) agree with a previously determined experimental result (9...
Nonlinear optical model for strip plasmonic waveguides
Lysenko, Oleg; Bache, Morten; Lavrinenko, Andrei
2016-01-01
This paper presents a theoretical model of nonlinear optical properties for strip plasmonic waveguides. The particular waveguides geometry that we investigate contains a gold core, adhesion layers, and silicon dioxide cladding. It is shown that the third-order susceptibility of the gold core...... significantly depends on the layer thickness and has the dominant contribution to the effective third-order susceptibility of the long-range plasmon polariton mode. This results in two nonlinear optical effects in plasmonic waveguides, which we experimentally observed and reported in [Opt. Lett. 41, 317 (2016......)]. The first effect is the nonlinear power saturation of the plasmonic mode, and the second effect is the spectral broadening of the plasmonic mode. Both nonlinear plasmonic effects can be used for practical applications and their appropriate model will be important for further developments in communication...
A Thermo-Optic Propagation Modeling Capability.
Schrader, Karl; Akau, Ron
2014-10-01
A new theoretical basis is derived for tracing optical rays within a finite-element (FE) volume. The ray-trajectory equations are cast into the local element coordinate frame and the full finite-element interpolation is used to determine instantaneous index gradient for the ray-path integral equation. The FE methodology (FEM) is also used to interpolate local surface deformations and the surface normal vector for computing the refraction angle when launching rays into the volume, and again when rays exit the medium. The method is implemented in the Matlab(TM) environment and compared to closed- form gradient index models. A software architecture is also developed for implementing the algorithms in the Zemax(TM) commercial ray-trace application. A controlled thermal environment was constructed in the laboratory, and measured data was collected to validate the structural, thermal, and optical modeling methods.
FU Hong-Bin; WANG Bao-Hong; DING Bao-Wei; LIU Zhao-Yuan
2009-01-01
The classical method within the independent electron model is employed to investigate (i) charge dependences of single and double ionization for helium by various charged ions Aq+ (q = 1 - 8) at impact energies of 0.64 and 1.44 MeV/u, respectively, (ii) energy dependences of transfer ionization for helium by 0.5-3 MeV/u A8,9+ ions impact. The Lenz-Jensen model of the atom is applied instead of the Bohr model of the atom, and the impact-parameter dependences are also introduced into the calculations. Satisfactory agreement is found between theoretical and experimental data.
Optical model predictions for total cross sections for scattering of neutrons from {sup 40}Ca
Chinn C.R.; Elster, C.; Thaler, R.M.
1993-10-01
Measurements of neutron total cross sections are both extensive and extremely accurate. Although they should place a strong constraint on theoretically constructed optical models, there are relatively few comparisons of optical model predictions with those experiments. We have calculated total cross sections for neutron scattering from {sup 40}Ca as a function of energy from 100 - 600 MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although the results are already in qualitative agreement with the data, the inclusion of medium corrections to the propagator using a recently derived microscopic mean field approach, is essential for correctly predicting the energy dependence given by the experiment. In the region below 200 MeV, where our off-shell tp calculations over predict the experiment, the modification due to the nuclear medium reduces the calculated values, whereas above 200 MeV, these corrections tend to compensate for the under prediction of the off-shell t{rho} results.
Optical Coherence Tomography: Modeling and Applications
Thrane, Lars
in previous theoretical models of OCT systems. It is demonstrated that the shower curtain effect is of utmost importance in the theoretical description of an OCT system. The analytical model, together with proper noise analysis of the OCT system, enables calculation of the SNR, where the optical properties...... geometry, i.e., reflection geometry, is developed. As in the new OCT model, multiple scattered photons has been taken into account together with multiple scattering effects. As an important result, a novel method of creating images based on measurements of the momentum width of the Wigner phase......An analytical model is presented that is able to describe the performance of OCT systems in both the single and multiple scattering regimes simultaneously. This model inherently includes the shower curtain effect, well-known for light propagation through the atmosphere. This effect has been omitted...
Green Network Planning Model for Optical Backbones
Gutierrez Lopez, Jose Manuel; Riaz, M. Tahir; Jensen, Michael
2010-01-01
Communication networks are becoming more essential for our daily lives and critically important for industry and governments. The intense growth in the backbone traffic implies an increment of the power demands of the transmission systems. This power usage might have a significant negative effect...... on the environment in general. In network planning there are existing planning models focused on QoS provisioning, investment minimization or combinations of both and other parameters. But there is a lack of a model for designing green optical backbones. This paper presents novel ideas to be able to define...
The energy dependence of the diffraction minimum in the elastic scattering and new LHC data
Selyugin, O. V.
2017-03-01
The soft diffraction phenomena in the elastic proton-proton scattering are reviewed from the viewpoint of experiments at the LHC (TOTEM and ATLAS collaboration). In the framework of the High Energy Generalized Structure (HEGS) model the form of the diffraction minimum in the nucleon-nucleon elastic scattering in a wide energy region is analyzed. The energy dependencies of the main characteristics of the diffraction dip are obtained. The numerical predictions at LHC energies are presented. The comparison of the model predictions with the new LHC data at √{ s} = 13 TeV is made.
Optics Corrections with LOCO in the Fermilab Booster
Tan, Cheng-Yang [Fermilab; Prost, Lionel [Fermilab; Seiya, Kiyomi [Fermilab; Triplett, A. Kent [Fermilab
2016-06-01
The optics of the Fermilab Booster has been corrected with LOCO (Linear Optics from Closed Orbits). However, the first corrections did not show any improvement in capture efficiency at injection. A detailed analysis of the results showed that the problem lay in the MADX optics file. Both the quadrupole and chromatic strengths were originally set as constants independent of beam energy. However, careful comparison between the measured and calculated tunes and chromatcity show that these strengths are energy dependent. After the MADX model was modified with these new energy dependent strengths, the LOCO corrected lattice has been applied to Booster. The effect of the corrected lattice will be discussed here.
Symbolic modeling of high energy beam optics
Autin, Bruno
1999-01-01
A classical problem of computational physics consists of finding the minimum of a chi /sup 2/ like function of many variables. Powerful optimization algorithms have been developed but do not guarantee convergence towards an absolute minimum. Analytical methods can improve the insight into a physical problem but calculations quickly exceed the power of a human brain. There comes the interest of optical design of high energy particle accelerators. The physics background is sketched and emphasis is put on the methodology. In practice, algebraic models may not be precise enough but they usually provide excellent initial conditions for a final numerical optimization. (4 refs).
Optical Model and Cross Section Uncertainties
Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.
2009-10-05
Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.
Optical modeling and simulation of thin-film photovoltaic devices
Krc, Janez
2013-01-01
In wafer-based and thin-film photovoltaic (PV) devices, the management of light is a crucial aspect of optimization since trapping sunlight in active parts of PV devices is essential for efficient energy conversions. Optical modeling and simulation enable efficient analysis and optimization of the optical situation in optoelectronic and PV devices. Optical Modeling and Simulation of Thin-Film Photovoltaic Devices provides readers with a thorough guide to performing optical modeling and simulations of thin-film solar cells and PV modules. It offers insight on examples of existing optical models
Theoretical model for a Stark anomalous dispersion optical filter
Yin, B.; Shay, T. M.
1993-01-01
A theoretical model for the first atomic Stark anomalous dispersion optical filter is reported. The results show the filter may serve as a widely tunable narrow bandwidth and high throughput optical filter for freespace laser communications and remote sensing.
RECENT MATHEMATICAL STUDIES IN THE MODELING OF OPTICS AND ELECTROMAGNETICS
Gang Bao
2004-01-01
This work is concerned with mathematical modeling, analysis, and computation of optics and electromagnetics, motivated particularly by optical and microwave applications.The main technical focus is on Maxwell's equations in complex linear and nonlinear media.
Morcelle, Viviane; Gomes, P.R.S.; Lubian, J.; Mendes Junior, D.R. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Lichtenthaeler, R.; Guimaraes, V.; Lepine-Szily, A.; Camargo, O.; Faria, P.N. de; Gasquez, L.; Morais, M.C.; Condori, R.P.; Pires, K.C.C.; Scarduelli, V. [Universidade de Sao Paulo (USP), SP (Brazil); Barioni, A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Zamora, J.C. [Technische Universitaet Darmstadt (Germany); Aguilera, E.; Martinez-Quiroz, E. [Instituto Nacional de Investigaciones Nucleares (Mexico); Kolata, J.; Jiang, H. [University of Notre Dame, IN (United States); Bechetti, F.D.; Lamm, L.O. [Michigan University, MI (United States); Lizcano, D. [Universidad Autonoma del Estado de Mexico (Mexico)
2012-07-01
Full text: Elastic scattering measurements were performed at energies around the Coulomb barrier at the Tandem Accelerators of the Sao Paulo (USP - Brazil ) and Notre Dame (UND - USA) Universities. The {sup 7}Be is a radioactive nucleus and has been produced by the reaction {sup 6}He({sup 6}Li,{sup 9}Be) and impinged on {sup 27}Al and {sup 197}Au secondary targets using a double superconducting systems RIBRAS ( USP ) and Twinsol (UND). The elastic scattering angular distributions were analyzed through the optical model calculations, using the Woods- Saxon form factors [1] and the Sao Paulo potential [2] to fit the experimental data. The total reaction cross sections were also derived and compared with others presented at the literature for other systems. In addition, a study of the nuclear potential energy dependence has been carried out in this work in the dispersion relation context. Due to the fact that {sup 7}Be has a small breakup threshold energy, the results can provide significant information of the influence of the breakup channel on the reactions involving this projectile. For this purpose, {chi}{sup 2}- data analysis with different kind of potentials were performed to identify the energy dependence of the real (V) and imaginary (W) parts of the potential. [1] L.C. Chamon et al., Phys. Rev. C 66, (2002) 014610. [2] R.D. Wood e D.S. Saxon, Phys. Rev. 95 ( 1954) 577. (author)
Musolino, S.; Chiofalo, M.-L.
2017-07-01
We consider the BCS-BEC crossover of a quantum Fermi gas at T = 0 in the presence of an energy-dependent Fano-Feshbach resonance, driving the system from broad to narrow limits. We choose a minimal microscopic potential reproducing the two-particle resonance physics in terms of the scattering length a and the effective range R∗ representing the resonance width, and solve the BCS mean-field equations varying a, R∗ and the density. We show that the condensate fraction manifests a universal behavior when the correlation length, measuring the pair size, is used as the crossover parameter. Generally, a negative effective range has the effect of stretching the crossover region between the two extreme regimes, as evidenced by the behavior of the chemical potential. These results can be useful in view of the more recent perspectives of realizing narrow resonances also by optical means and amenable as a base quantum Monte Carlo simulations.
On the energy dependence of proton beam extraction with a bent crystal
Arduini, G.; Elsener, K.; Fidecaro, G.; Gyr, M.; Herr, W.; Klem, J.; Mikkelsen, U.; Weisse, E.
1998-03-01
Proton beam extraction from the CERN SPS by means of a bent silicon crystal is reported at three different energies, 14 GeV, 120 GeV and 270 GeV. The experimental results are compared to computer simulations which contain a sound model of the SPS accelerator as well as the channeling phenomena in bent crystals. The overall energy dependence of crystal assisted proton beam extraction is understood and provides the basis to discuss such a scheme for future accelerators. © 1998
Optical Performance Modeling of FUSE Telescope Mirror
Saha, Timo T.; Ohl, Raymond G.; Friedman, Scott D.; Moos, H. Warren
2000-01-01
We describe the Metrology Data Processor (METDAT), the Optical Surface Analysis Code (OSAC), and their application to the image evaluation of the Far Ultraviolet Spectroscopic Explorer (FUSE) mirrors. The FUSE instrument - designed and developed by the Johns Hopkins University and launched in June 1999 is an astrophysics satellite which provides high resolution spectra (lambda/Delta(lambda) = 20,000 - 25,000) in the wavelength region from 90.5 to 118.7 nm The FUSE instrument is comprised of four co-aligned, normal incidence, off-axis parabolic mirrors, four Rowland circle spectrograph channels with holographic gratings, and delay line microchannel plate detectors. The OSAC code provides a comprehensive analysis of optical system performance, including the effects of optical surface misalignments, low spatial frequency deformations described by discrete polynomial terms, mid- and high-spatial frequency deformations (surface roughness), and diffraction due to the finite size of the aperture. Both normal incidence (traditionally infrared, visible, and near ultraviolet mirror systems) and grazing incidence (x-ray mirror systems) systems can be analyzed. The code also properly accounts for reflectance losses on the mirror surfaces. Low frequency surface errors are described in OSAC by using Zernike polynomials for normal incidence mirrors and Legendre-Fourier polynomials for grazing incidence mirrors. The scatter analysis of the mirror is based on scalar scatter theory. The program accepts simple autocovariance (ACV) function models or power spectral density (PSD) models derived from mirror surface metrology data as input to the scatter calculation. The end product of the program is a user-defined pixel array containing the system Point Spread Function (PSF). The METDAT routine is used in conjunction with the OSAC program. This code reads in laboratory metrology data in a normalized format. The code then fits the data using Zernike polynomials for normal incidence
Optical modeling of Fresnel zoneplate microscopes.
Naulleau, Patrick P; Mochi, Iacopo; Goldberg, Kenneth A
2011-07-10
Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes routinely used in the synchrotron community.
Optics damage modeling and analysis at the National Ignition Facility
Liao, Z. M.; Raymond, B.; Gaylord, J.; Fallejo, R.; Bude, J.; Wegner, P.
2014-10-01
Comprehensive modeling of laser-induced damage in optics for the National Ignition Facility (NIF) has been performed on fused silica wedge focus lenses with a metric that compares the modeled damage performance to online inspections. The results indicate that damage models are successful in tracking the performance of the fused silica final optics when properly accounting for various optical finishes and mitigation processes. This validates the consistency of the damage models and allows us to further monitor and evaluate different system parameters that potentially can affect optics performance.
Nucleon scattering on actinides using a dispersive optical model with extended couplings
SoukhovitskiÄ©, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.; Martyanov, D. S.
2016-12-01
The Tamura coupling model [Rev. Mod. Phys. 37, 679 (1965), 10.1103/RevModPhys.37.679] has been extended to consider the coupling of additional low-lying rotational bands to the ground-state band. Rotational bands are built on vibrational bandheads (even-even targets) or single-particle bandheads (odd-A targets) including both axial and nonaxial deformations. These additional excitations are introduced as a perturbation to the underlying axially symmetric rigid-rotor structure of the ground-state rotational band. Coupling matrix elements of the generalized optical model are derived for extended multiband transitions in even-even and odd-A nuclei. Isospin symmetric formulation of the optical model is employed. A coupled-channels optical-model potential (OMP) containing a dispersive contribution is used to fit simultaneously all available optical experimental databases including neutron strength functions for nucleon scattering on 232Th,233,235,238U, and 239Pu nuclei. Quasielastic (p ,n ) scattering data on 232Th and 238U to the isobaric analog states of the target nucleus are also used to constrain the isovector part of the optical potential. Lane consistent OMP is derived for all actinides if corresponding multiband coupling schemes are defined. For even-even (odd-A ) actinides almost all low-lying collective levels below 1 MeV (0.5 MeV) of excitation energy are coupled. OMP parameters show a smooth energy dependence and energy-independent geometry. A phenomenological optical-model potential that couples multiple bands in odd-A actinides is published for a first time. Calculations using the derived OMP potential reproduce measured total cross-section differences between several actinide pairs within experimental uncertainty for incident neutron energies from 50 keV up to 150 MeV. The importance of extended coupling is studied. Multiband coupling is stronger in even-even targets owing to the collective nature of the coupling; the impact of extended coupling on
Classical and quantum dynamics of a perfect fluid scalar-energy dependent metric cosmology
Khodadi, M; Vakili, B
2016-01-01
Inspired from the idea of minimally coupling of a real scalar field to geometry, we investigate the classical and quantum models of a flat energy-dependent FRW cosmology coupled to a perfect fluid in the framework of the scalar-rainbow metric gravity. We use the standard Schutz' representation for the perfect fluid and show that under a particular energy-dependent gauge fixing, it may lead to the identification of a time parameter for the corresponding dynamical system. It is shown that, under some circumstances on the minisuperspace prob energy, the classical evolution of the of the universe represents a late time expansion coming from a bounce instead of the big-bang singularity. Then we go forward by showing that this formalism gives rise to a Schr\\"{o}dinger-Wheeler-DeWitt (SWD) equation for the quantum-mechanical description of the model under consideration, the eigenfunctions of which can be used to construct the wave function of the universe. We use the resulting wave function in order to investigate t...
Classical and quantum dynamics of a perfect fluid scalar-energy dependent metric cosmology
Khodadi, M.; Nozari, K.; Vakili, B.
2016-05-01
Inspired from the idea of minimally coupling of a real scalar field to geometry, we investigate the classical and quantum models of a flat energy-dependent FRW cosmology coupled to a perfect fluid in the framework of the scalar-rainbow metric gravity. We use the standard Schutz' representation for the perfect fluid and show that under a particular energy-dependent gauge fixing, it may lead to the identification of a time parameter for the corresponding dynamical system. It is shown that, under some circumstances on the minisuperspace prob energy, the classical evolution of the of the universe represents a late time expansion coming from a bounce instead of the big-bang singularity. Then we go forward by showing that this formalism gives rise to a Schrödinger-Wheeler-DeWitt equation for the quantum-mechanical description of the model under consideration, the eigenfunctions of which can be used to construct the wave function of the universe. We use the resulting wave function in order to investigate the possibility of the avoidance of classical singularities due to quantum effects by means of the many-worlds and Bohmian interpretation of quantum cosmology.
Uncertainty Quantification for Optical Model Parameters
Lovell, A E; Sarich, J; Wild, S M
2016-01-01
Although uncertainty quantification has been making its way into nuclear theory, these methods have yet to be explored in the context of reaction theory. For example, it is well known that different parameterizations of the optical potential can result in different cross sections, but these differences have not been systematically studied and quantified. The purpose of this work is to investigate the uncertainties in nuclear reactions that result from fitting a given model to elastic-scattering data, as well as to study how these uncertainties propagate to the inelastic and transfer channels. We use statistical methods to determine a best fit and create corresponding 95\\% confidence bands. A simple model of the process is fit to elastic-scattering data and used to predict either inelastic or transfer cross sections. In this initial work, we assume that our model is correct, and the only uncertainties come from the variation of the fit parameters. We study a number of reactions involving neutron and deuteron p...
Classical Ising Models Realised on Optical Lattices
Cirio, Mauro; Brennen, G. K.; Twamley, J.; Iblisdir, S.; Boada, O.
2012-02-01
We describe a simple quantum algorithm acting on a register of qubits in d spatial dimensions which computes statistical properties of d+1 dimensional classical Ising models. The algorithm works by measuring scattering matrix elements for quantum processes and Wick rotating to provide estimates for real partition functions of classical systems. This method can be implemented in a straightforward way in ensembles of qubits, e.g. three dimensional optical lattices with only nearest neighbor Ising like interactions. By measuring noise in the estimate useful information regarding location of critical points and scaling laws can be extracted for classical Ising models, possibly with inhomogeneity. Unlike the case of quantum simulation of quantum hamiltonians, this algorithm does not require Trotter expansion of the evolution operator and thus has the advantage of being amenable to fault tolerant gate design in a straightforward manner. Through this setting it is possible to study the quantum computational complexity of the estimation of a classical partition function for a 2D Ising model with non uniform couplings and magnetic fields. We provide examples for the 2 dimensional case.
Energy Dependence and Scaling Property of Localization Length near a Gapped Flat Band
Ge, Li
2015-01-01
Using a tight-binding model for a one-dimensional Lieb lattice, we show that the localization length near a gapped flat band behaves differently from the typical Urbach tail in a band gap: instead of reducing monotonically as the energy E moves away from the flat band energy E_{FB}, the presence of the flat band causes a nonmonotonic energy dependence of the localization length. This energy dependence follows a scaling property when the energy is within the spread (W) of uniformly distributed diagonal disorder, i.e. the localization length is only a function of (E-E_{FB})/W. Several other lattices are compared to distinguish the effect of the flat band on the localization length, where we eliminate, shift, or duplicate the flat band, without changing the dispersion relations of other bands. Using the top right element of the Green's matrix, we derive an analytical relation between the density of states and the localization length, which shines light on these properties of the latter, including a summation rul...
Energy Dependence of the πN Amplitude and the Three-Nucleon Interaction
Saito, T.-Y.; Afnan, I. R.
1995-08-01
By calculating the contribution of the ππ three-body force to the three-nucleon binding energy in terms of the πN amplitude using perturbation theory, we are able to determine the importance of the energy dependence and the contribution of the different partial waves of the πN amplitude to the three-nucleon force. A separable representation of the non-pole πN amplitude allows us to write the three-nucleon force in terms of the amplitude for NN → NN*, propagation of the NNN* system, and the amplitude for NN* → NN , with N* being the πN quasi-particle amplitude in a given state. The division of the πN amplitude into a pole and non-pole part gives a procedure for the determination of the πNN form factor within the model. The total contribution of the three-body force to the binding energy of the triton for the separable approximation to the Paris nucleon-nucleon potential (PEST) is found to be very small mainly as a result of the energy dependence of the πN amplitude, the cancellation between the S- and P-wave πN amplitudes, and the soft πNN form factor.
The energy dependence of the $\\pi$N amplitude and the three-nucleon interaction
Saitô, T; Saito, T Y
1994-01-01
By calculating the contribution of the \\pi-\\pi three-body force to the three-nucleon binding energy in terms of the \\pi N amplitude using perturbation theory, we are able to determine the importance of the energy dependence and the contribution of the different partial waves of the \\pi N amplitude to the three-nucleon force. A separable representation of the non-pole \\pi N amplitude allows us to write the three-nucleon force in terms of the amplitude for NN\\rightarrow NN^*, propagation of the NNN^* system, and the amplitude for NN^*\\rightarrow NN, with N^* being the \\pi N quasi-particle amplitude in a given state. The division of the \\pi N amplitude into a pole and non-pole gives a procedure for the determination of the \\pi NN form factor within the model. The total contribution of the three-body force to the binding energy of the triton for the separable approximation to the Paris nucleon-nucleon potential (PEST) is found to be very small mainly as a result of the energy dependence of the \\pi N amplitude, th...
Energy Dependence of Pion and Kaon Production in Central Pb+Pb Collisions
Afanasiev, S V; Barna, D; Bartke, Jerzy; Barton, R A; Behler, M; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Blyth, C O; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncic, P; Cerny, V; Cramer, J G; Csató, P; Dinkelaker, P; Eckhardt, V; Filip, P; Fodor, Z; Foka, P Y; Freund, P; Friese, V; Gál, J; Gazdzicki, M; Georgopoulos, G; Gladysz-Dziadus, E; Hegyi, S; Höhne, C; Igo, G; Jones, P G; Kadija, K; Karev, A; Kolesnikov, V I; Kollegger, T; Kowalski, M; Kraus, I; Kreps, M; Van Leeuwen, M; Lévai, Peter; Malakhov, A I; Margetis, S; Markert, C; Mayes, B W; Melkumov, G L; Mischke, A; Molnár, J; Nelson, J M; Pálla, G; Panagiotou, A D; Perl, K; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R E; Retyk, W; Roland, C; Roland, G; Rybicki, A; Sammer, T; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Squier, G T A; Stock, Reinhard; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Varga, D; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Whitten, C; Yoo, I K; Zaranek, J; Zimányi, J
2002-01-01
Results on the energy dependence of charged pion and kaon production in central Pb+Pb collisions at 40, 80 and 158 A GeV are presented and compared with data at lower and higher energies. The mean pion multiplicity increases approximately linearly with s^{1/4} with a change of slope around 40 A GeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies also occurs at about 40 A GeV. A non-monotonic energy dependence of the ratio of K+ to pi+ yields is observed, with a maximum close to 40 A GeV, followed by a nearly constant value at higher energies. The measured dependences are consistent with the hypothesis, derived within a Statistical Model of the Early Stage of nucleus-nucleus reactions, that a transient state of deconfined matter is created in Pb+Pb collisions for energies larger than about 40 A GeV.
Modeling GMPLS and Optical MPLS Networks
Christiansen, Henrik Lehrmann; Wessing, Henrik
2003-01-01
A consequence of migrating the existing Internet architecture to an all-optical one is that the network will consist of a mixture of equipment, ranging from electrical routers to all-optical packet switches. Hence, future networks will consist of multiple domains employing different technologies...
Quantum Modelling of Electro-Optic Modulators
Capmany, Jose
2011-01-01
Many components that are employed in quantum information and communication systems are well known photonic devices encountered in standard optical fiber communication systems, such as optical beamsplitters, waveguide couplers and junctions, electro-optic modulators and optical fiber links. The use of these photonic devices is becoming increasingly important especially in the context of their possible integration either in a specifically designed system or in an already deployed end-to-end fiber link. Whereas the behavior of these devices is well known under the classical regime, in some cases their operation under quantum conditions is less well understood. This paper reviews the salient features of the quantum scattering theory describing both the operation of the electro-optic phase and amplitude modulators in discrete and continuous-mode formalisms. This subject is timely and of importance in light of the increasing utilization of these devices in a variety of systems, including quantum key distribution an...
Novel applications of the dispersive optical model
Dickhoff, W H; Mahzoon, M H
2016-01-01
A review of recent developments of the dispersive optical model (DOM) is presented. Starting from the original work of Mahaux and Sartor, several necessary steps are developed and illustrated which increase the scope of the DOM allowing its interpretation as generating an experimentally constrained functional form of the nucleon self-energy. The method could therefore be renamed as the dispersive self-energy method. The aforementioned steps include the introduction of simultaneous fits of data for chains of isotopes or isotones allowing a data-driven extrapolation for the prediction of scattering cross sections and level properties in the direction of the respective drip lines. In addition, the energy domain for data was enlarged to include results up to 200 MeV where available. An important application of this work was implemented by employing these DOM potentials to the analysis of the (\\textit{d,p}) transfer reaction using the adiabatic distorted wave approximation (ADWA). We review the fully non-local DOM...
Optical Turbulence Characterization at LAMOST Site: Observations and Models
Liu, L -Y; Yao, Y -Q; Vernin, J; Chadid, M; Wang, H -S; Yin, J; Wang, Y -P
2015-01-01
Atmospheric optical turbulence seriously limits the performance of high angular resolution instruments. An 8-night campaign of measurements was carried out at the LAMOST site in 2011, to characterize the optical turbulence. Two instruments were set up during the campaign: a Differential Image Motion Monitor (DIMM) used to measure the total atmospheric seeing, and a Single Star Scidar (SSS) to measure the vertical profiles of the turbulence C_n^2(h) and the horizontal wind velocity V(h). The optical turbulence parameters are also calculated with the Weather Research and Forecasting (WRF) model coupled with the Trinquet-Vernin model, which describes optical effects of atmospheric turbulence by using the local meteorological parameters. This paper presents assessment of the optical parameters involved in high angular resolution astronomy. Its includes seeing, isoplanatic angle, coherence time, coherence etendue, vertical profiles of optical turbulence intensity _n^2(h)$ and horizontal wind speed V(h). The median...
A novel model on dynamic resource allocation in optical networks
TANG Yong; RAO Min; LI Lei; CHEN Yu; JIANG Jianfeng; ZHANG Mingde; SUN Xiaohan
2005-01-01
A novel model on dynamic resource allocation in the WDM optical networks is proposed, basing on the integrated considerations of the impacts of transmission impairments and service classification on dynamic resource allocation in the optical layer.In this model, the priorities of optical connection requests are mapped into different thresholds of transmission impairments, and a uniform method which is adopted to evaluate the virtual wavelength path (VWP) candidates is defined. The Advanced Preferred Wavelength Sets Algorithm (A-PWS) and the heuristic Dynamic Min-Cost & Optical Virtual Wavelength Path Algorithm (DMC-OVWP) are presented addressing the routing and wavelength assignment (RWA) problem based on dynamic traffic and multi priorities in wavelength-routed optical networks. For a received optical connection request,DMC-OVWP is employed to calculate a list of the VWP candidates, and an appropriate VWP which matches the request's priority is picked up to establish the lightpath by analyzing the transmission qualities of the VWP candidates.
On a Decomposition Model for Optical Flow
Abhau, Jochen; Belhachmi, Zakaria; Scherzer, Otmar
In this paper we present a variational method for determining cartoon and texture components of the optical flow of a noisy image sequence. The method is realized by reformulating the optical flow problem first as a variational denoising problem for multi-channel data and then by applying decomposition methods. Thanks to the general formulation, several norms can be used for the decomposition. We study a decomposition for the optical flow into bounded variation and oscillating component in greater detail. Numerical examples demonstrate the capabilities of the proposed approach.
Model GC1312S Multifunction Integrated Optical Circuit Devices
无
2001-01-01
Model GC1312S multifunction integrated optical circuit device (MIOC) used in inertial-grade interferometric fiber optics gyroscopes (IFOGs) is fabricated by annealing and proton exchange process (APE). The unique feature of the device is the incorporation of the beat detection circuit besides all the features the conventional single Y-branch multifunction integrated optical circuit devices have. The device structure, operation principle and typical characteristics, etc., are briefly presented in this paper.
Measuring optical properties of a blood vessel model using optical coherence tomography
Levitz, David; Hinds, Monica T.; Tran, Noi; Vartanian, Keri; Hanson, Stephen R.; Jacques, Steven L.
2006-02-01
In this paper we develop the concept of a tissue-engineered optical phantom that uses engineered tissue as a phantom for calibration and optimization of biomedical optics instrumentation. With this method, the effects of biological processes on measured signals can be studied in a well controlled manner. To demonstrate this concept, we attempted to investigate how the cellular remodeling of a collagen matrix affected the optical properties extracted from optical coherence tomography (OCT) images of the samples. Tissue-engineered optical phantoms of the vascular system were created by seeding smooth muscle cells in a collagen matrix. Four different optical properties were evaluated by fitting the OCT signal to 2 different models: the sample reflectivity ρ and attenuation parameter μ were extracted from the single scattering model, and the scattering coefficient μ s and root-mean-square scattering angle θ rms were extracted from the extended Huygens-Fresnel model. We found that while contraction of the smooth muscle cells was clearly evident macroscopically, on the microscopic scale very few cells were actually embedded in the collagen. Consequently, no significant difference between the cellular and acellular samples in either set of measured optical properties was observed. We believe that further optimization of our tissue-engineering methods is needed in order to make the histology and biochemistry of the cellular samples sufficiently different from the acellular samples on the microscopic level. Once these methods are optimized, we can better verify whether the optical properties of the cellular and acellular collagen samples differ.
Energy dependence of event shapes and of $\\alpha_s$ at LEP 2
Abreu, P; Adye, T; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Beillière, P; Belokopytov, Yu A; Belous, K S; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschbeck, Brigitte; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Ferro, F; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, J; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Maltezos, S; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Masik, J; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Nassiakou, M; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwering, B; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
1999-01-01
Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at ve di erent centre of mass energies above $M_Z$ with the DELPHI detector at LEP. From the event shapes, the strong coupling $\\alpha_s$ is extracted in $O(\\alpha^2_s)$, NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at MZ, the energy dependence (running) of $\\alpha_s$ is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be $d\\alpha_{s}^{-1}/d log(E_{cm}) = 1.39 \\pm 0.34(stat) \\pm 0.17(syst)$, in good agreement with the QCD expectation of 1.27.
Mueller, Bernhard
2009-05-07
In this thesis, we have presented the first multi-dimensional models of core-collapse supernovae that combine a detailed, up-to-date treatment of neutrino transport, the equation of state, and - in particular - general relativistic gravity. Building on the well-tested neutrino transport code VERTEX and the GR hydrodynamics code CoCoNuT, we developed and implemented a relativistic generalization of a ray-by-ray-plus method for energy-dependent neutrino transport. The result of these effort, the VERTEX-CoCoNuT code, also incorporates a number of improved numerical techniques that have not been used in the code components VERTEX and CoCoNuT before. In order to validate the VERTEX-CoCoNuT code, we conducted several test simulations in spherical symmetry, most notably a comparison with the one-dimensional relativistic supernova code AGILE-BOLTZTRAN and the Newtonian PROMETHEUSVERTEX code. (orig.)
无
2001-01-01
On the basis of analysis on the temperature monitoring methods for high voltage devices, a new type of fiber optic sensor structure with reference channel is given. And the operation principle of fiber optic sensor is analysed at large based on the absorption of semiconductor chip. The mathematical model of both devices and the whole system are also given. It is proved by the experiment that this mathematical model is reliable.
The Maxwell-Lorentz Model for optical Pulses
Sørensen, Mads Peter; Brio, Moysey
2007-01-01
Dynamics of optical pulses, especially of ultra short femtosecond pulses, are of great technological and theoretical interest. The dynamics of optical pulses is usually studied using the nonlinear Schrodinger (NLS) equation model. While such approach works surprisingly well for description of pulse...
HCMT models of optical microring-resonator circuits
Lohmeyer, Manfred
2010-01-01
Circuits of dielectric integrated optical microring resonators are addressed through a two-dimensional hybrid analytical/numerical coupled mode theory (HCMT) model. Analytical modes of all straight and curved cores form templates for the optical fields of the entire circuits. Our variational techniq
Activities at Los Alamos for the optical model segment of the RIPL CRP
Young, P.G.
1997-05-10
This report discusses activity at Los Alamos on the nuclear optical model. In particular, the following topics are discussed: format of the optical model parameter library; contents of the library; validation of the optical model library; and conclusions and recommendations.
BeamOptics : a Symbolic Platform for Modeling and the Solution of Beam Optics System
Yu-Chiu Chao
2000-11-01
BeamOptics [1] is a Mathematica-based computing platform devoted to the following objectives: (1) Structured representation and manipulation of particle beam optics systems with symbolic capabilities, (2) Analytical and numerical modeling of beam optics system behaviors, (3) Solution to specific beam optical or general accelerator system problems, in algebraic form in certain cases, through customized algorithms. Taking advantage of and conforming to the highly formal and self-contained structure of Mathematica, BeamOptics provides a unique platform for developing accelerator design and analysis programs. The feature of symbolic computation and the ability to manipulate the beam optics system at the programming language level enable the user to solve or optimize his system with considerably more efficiency, rigour and insight than can be easily achieved with passive modeling or numerical simulation methods. BeamOptics is developed with continuous evolution in mind. New features and algorithms from diverse sources can be incorporated without major modification, due to its formal and generic structure. In this report, a survey is given of the basic structure and methodology of BeamOptics, as well as a demonstration of some of its more specialized applications, and possible direction of evolution.
Photon energy dependence of angle-resolved photoemission spectroscopy in graphene
Ayria, Pourya; Nugraha, Ahmad R. T.; Hasdeo, Eddwi H.; Czank, Thomas R.; Tanaka, Shin-ichiro; Saito, Riichiro
2015-11-01
The photon energy dependence of angle-resolved photoemission spectroscopy (ARPES) in graphene is investigated experimentally and theoretically. By applying light with energy of around 46 eV , we found an unexpected increase in the ARPES relative intensity of graphene for the p branch (ARPES spectra brightened by the p -polarized light) with respect to the s branch (those brightened by the s -polarized light). The origin of the enhanced p -branch intensity is explained by first-principles calculations, in which we show (1) the optical dipole vector as a function of final-state energies of the excited electron, (2) the absorption intensity as a function of the incident light angle, and (3) the symmetry of the initial and the final states. The calculated results imply that the dipole vector of the excited electron near 46 eV has an exceptionally large component in the normal direction of the graphene surface compared to that within the graphene plane, which could be the main reason for the enhancement of the p -branch intensity.
Analytical models of optical response in one-dimensional semiconductors
Pedersen, Thomas Garm, E-mail: tgp@nano.aau.dk
2015-09-04
The quantum mechanical description of the optical properties of crystalline materials typically requires extensive numerical computation. Including excitonic and non-perturbative field effects adds to the complexity. In one dimension, however, the analysis simplifies and optical spectra can be computed exactly. In this paper, we apply the Wannier exciton formalism to derive analytical expressions for the optical response in four cases of increasing complexity. Thus, we start from free carriers and, in turn, switch on electrostatic fields and electron–hole attraction and, finally, analyze the combined influence of these effects. In addition, the optical response of impurity-localized excitons is discussed. - Highlights: • Optical response of one-dimensional semiconductors including excitons. • Analytical model of excitonic Franz–Keldysh effect. • Computation of optical response of impurity-localized excitons.
Energy dependence of the rho-trajectory intercept
Garcia, A.; Canal, C.A.G.; Masperi, L.
1978-02-01
The forward ..pi..N charge-exchange differential cross section is studied in the framework of a recent model for the rho trajectory. Negative result shed doubts on the proposed nondiffractive renormalization mechanism for secondary Reggeons.
Mark formation model for optical rewritable recording
Brusche, J.H.
2007-01-01
Optically rewritable discs contain one or more so-called recording stacks. These stacks consist of various grooved layers. At least one of these layers contains a so-called phase-change material. In the recording layer, amorphous regions are formed on a crystalline background by means of high power
Mark formation modeling in optical rewritable recording
Brusche, J.H.; Segal, A.; Vuik, C.; Urbach, H.P.
2006-01-01
In optical rewritable recording media, such as the Blu-ray Disc, amorphous marks are formed on a crystalline background of a phase-change layer, by means of short, high power laser pulses. In order to improve this data storage concept, it is of great importance to understand the mark formation
Mark formation modeling in optical rewritable recording
Brusche, J.H.; Segal, A.; Vuik, C.; Urbach, H.P.
2006-01-01
In optical rewritable recording media, such as the Blu-ray Disc, amorphous marks are formed on a crystalline background of a phase-change layer, by means of short, high power laser pulses. In order to improve this data storage concept, it is of great importance to understand the mark formation proce
Energy Dependence of the Fusion Barrier for Heavy Nuclear Systems
LIZhu-xia; WUXi-zhen; TIANJun-long; WANGNing
2003-01-01
The dynamical behavior of the fusion potential barrier for heavy nuclear systems is studied by means of the improved quantum molecular dynamics model. It is found that the fusion potential barrier experienced in a realistic fusion process (the dynamic fusion potential barrier) reduces with decrease of incident energies.
DISSYMMETRY MODEL OF MOLECULAR POLARIZABILITY AND OPTICAL ACTIVITY
周志华; 汤杰
1991-01-01
Dissymmetry model of molecular polarizability divided into some layers within a sphere,some rules and sequence according to the magnitude of polarizability replaced by bond refraction for many groups have been suggested.The relationship between the dissymmetry of molecular polarizability arrounding the dissymmetric carbon atom and the direction of optical activity has been discussed .The accuracy is above 95 persent to use our model and rules to determine over 6000 compounds of optical activity.
Soliton models in resonant and nonresonant optical ﬁbers
K Porsezian
2001-11-01
In this review, considering the important linear and nonlinear optical effects like group velocity dispersion, higher order dispersion, Kerr nonlinearity, self-steepening, stimulated Raman scattering, birefringence, self-induced transparency and various inhomogeneous effects in ﬁbers, the completely integrable concept and bright, dark and self-induced transparency soliton models in nonlinear ﬁber optics are discussed. Considering the above important optical effects, the different completely integrable soliton models in the form of nonlinear Schrödinger (NLS), NLS-MaxwellBloch (MB) type equations reported in the literature are discussed. Finally, solitons in stimulated Raman scattering (SRS) system is brieﬂy discussed.
Energy Dependence of Synchrotron X-Ray Rims in Tycho's Supernova Remnant
Tran, Aaron; Williams, Brian J.; Petre, Robert; Ressler, Sean M.; Reynolds, Stephen P.
2015-01-01
Several young supernova remnants exhibit thin X-ray bright rims of synchrotron radiation at their forward shocks. Thin rims require strong magnetic field amplification beyond simple shock compression if rim widths are only limited by electron energy losses. But, magnetic field damping behind the shock could produce similarly thin rims with less extreme field amplification. Variation of rim width with energy may thus discriminate between competing influences on rim widths. We measured rim widths around Tycho's supernova remnant in 5 energy bands using an archival 750 ks Chandra observation. Rims narrow with increasing energy and are well described by either loss-limited or damped scenarios, so X-ray rim width-energy dependence does not uniquely specify a model. But, radio counterparts to thin rims are not loss-limited and better reflect magnetic field structure. Joint radio and X-ray modeling favors magnetic damping in Tycho's SNR with damping lengths approximately 1-5% of remnant radius and magnetic field strengths approximately 50-400 micron G assuming Bohm diffusion. X-ray rim widths are approximately 1% of remnant radius, somewhat smaller than inferred damping lengths. Electron energy losses are important in all models of X-ray rims, suggesting that the distinction between loss-limited and damped models is blurred in soft X-rays. All loss-limited and damping models require magnetic fields approximately greater than 20 micron G, arming the necessity of magnetic field amplification beyond simple compression.
Energy dependence of resonance production in relativistic heavy ion collisions
Shao, Feng-lan; Wang, Rui-qin; Zhang, Mao-sheng
2016-01-01
The production of hadronic resonances $K^{*}(892)$, $\\phi(1020)$, $\\Sigma^{*}(1385)$, and $\\Xi^{*}(1530)$ in central AA collisions at $\\sqrt{s_{NN}}=$ 17.3, 200, and 2760 GeV are systematically studied. The direct production of these resonances at system hadronization are described by the quark combination model and the effects of hadron multiple-scattering stage are dealt with by a ultra-relativistic quantum molecular dynamics model (UrQMD). We study the contribution of these two production sources to final observation and compare the final spectra with the available experimental data. The $p_T$ spectra of $K^{*}(892)$ calculated directly by quark combination model are explicitly higher than the data at low $p_T \\lesssim 1.5$ GeV and taking into account the modification of rescattering effects the resulting final spectra well agree with the data at all three collision energies. The rescattering effect on $\\phi(1020)$ production is weak and including it can slightly improve our description at low $p_T$ on the...
Energy dependence of resonance production in relativistic heavy ion collisions
Shao, Feng-Lan; Song, Jun; Wang, Rui-Qin; Zhang, Mao-Sheng
2017-01-01
The production of the hadronic resonances K*0(892), ϕ(1020), Σ*(1385), and Ξ*(1530) in central AA collisions at , 200, and 2760 GeV is systematically studied. The direct production of these resonances at system hadronization is described by the quark combination model and the effects of hadron multiple-scattering stage are dealt with by a ultra-relativistic quantum molecular dynamics model (UrQMD). We study the contribution of these two production sources to final observation and compare the final spectra with the available experimental data. The p T spectra of K*0(892) calculated directly by quark combination model are explicitly higher than the data at low p T ≲ 1.5 GeV, and taking into account the modification of rescattering effects, the resulting final spectra well agree with the data at all three collision energies. The rescattering effect on ϕ(1020) production is weak and including it can slightly improve our description at low p T on the basis of overall agreement with the data. We also predict the p T spectra of Σ*(1385) and Ξ*(1530), to be tested by the future experimental data. Supported by National Natural Science Foundation of China (11575100, 11305076, 11505104)
Hamadou, A.; Thobel, J.-L.; Lamari, S.
2016-10-01
A four level rate equations model for a terahertz optically pumped electrically driven quantum cascade laser is here introduced and used to model the system both analytically and numerically. In the steady state, both in the presence and absence of the terahertz optical field, we solve the resulting nonlinear system of equations and obtain closed form expressions for the levels occupation, population inversion as well as the mid-infrared pump threshold intensity in terms of the device parameters. We also derive, for the first time for this system, an analytical formula for the optical external efficiency and analyze the simultaneous effects of the cavity length and pump intensity on it. At moderate to high pump intensities, we find that the optical external efficiency scales roughly as the reciprocal of the cavity length.
Study of Optical Models Regarding the Human Eye
Maryam Abolmasoomi
2011-03-01
Full Text Available Introduction: Until now, many models have been presented for optical study of the human eye. In recent years, surgery on the anterior section of the eye (such as cataract and photo-refractive surgery has increased, so a study on the optics of the eye and evaluation of vision quality has become more important. Material and Methods: In this article, some of these models are considered. They include models with spherical and conic-section surfaces (for cornea and lens, simple models and new models with complex surfaces. Results: Evaluation of the optical models of the eye provides the possibility of enhancing the representation of human vision and also increasing the accuracy of surgery on the anterior section of the eye to enable higher quality vision.
Theoretical model for a Faraday anomalous dispersion optical filter
Yin, B.; Shay, T. M.
1991-01-01
A model for the Faraday anomalous dispersion optical filter is presented. The model predicts a bandwidth of 0.6 GHz and a transmission peak of 0.98 for a filter operating on the Cs (D2) line. The model includes hyperfine effects and is valid for arbitrary magnetic fields.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F. D.; Hagel, K.; Kühn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O.; Charity, R. J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K. D.; Holzmann, R.; Mayer, R. S.; Simon, R. S.; Wessels, J. P.; Casini, G.; Olmi, A.; Stefanini, A. A.
1992-07-01
High-energy γ rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of 136Xe+48Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width Γ is studied as a function of the fragment excitation energy E*. A saturation at about Γ=10 MeV is observed for E*/A>=1.0 MeV/nucleon.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F.D.; Hagel, K.; Kuehn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O. (II. Physikalisches Institut, Universitaet, Giessen, Giessen (Germany)); Charity, R.J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K.D.; Holzmann, R.; Mayer, R.S.; Simon, R.S.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung Darmstadt, Darmstadt (Germany)); Casini, G.; Olmi, A.; Stefanini, A.A. (Istituto Nazionale di Fisica Nucleare and University of Florence, Florence (Italy))
1992-07-13
High-energy {gamma} rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of {sup 136}Xe+{sup 48}Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width {Gamma} is studied as a function of the fragment excitation energy {ital E}{sup *}. A saturation at about {Gamma}=10 MeV is observed for {ital E}{sup *}/{ital A}{ge}1.0 MeV/nucleon.
Modeling plasmonic scattering combined with thin-film optics.
Schmid, M; Klenk, R; Lux-Steiner, M Ch; Topic, M; Krc, J
2011-01-14
Plasmonic scattering from metal nanostructures presents a promising concept for improving the conversion efficiency of solar cells. The determination of optimal nanostructures and their position within the solar cell is crucial to boost the efficiency. Therefore we established a one-dimensional optical model combining plasmonic scattering and thin-film optics to simulate optical properties of thin-film solar cells including metal nanoparticles. Scattering models based on dipole oscillations and Mie theory are presented and their integration in thin-film semi-coherent optical descriptions is explained. A plasmonic layer is introduced in the thin-film structure to simulate scattering properties as well as parasitic absorption in the metal nanoparticles. A proof of modeling concept is given for the case of metal-island grown silver nanoparticles on glass and ZnO:Al/glass substrates. Using simulations a promising application of the nanoparticle integration is shown for the case of CuGaSe(2) solar cells.
Optical Propagation Modeling for the National Ignition Facility
Williams, W H; Auerbach, J M; Henesian, M A; Jancaitis, K S; Manes, K R; Mehta, N C; Orth, C D; Sacks, R A; Shaw, M J; Widmayer, C C
2004-01-12
Optical propagation modeling of the National Ignition Facility has been utilized extensively from conceptual design several years ago through to early operations today. In practice we routinely (for every shot) model beam propagation starting from the waveform generator through to the target. This includes the regenerative amplifier, the 4-pass rod amplifier, and the large slab amplifiers. Such models have been improved over time to include details such as distances between components, gain profiles in the laser slabs and rods, transient optical distortions due to the flashlamp heating of laser slabs, measured transmitted and reflected wavefronts for all large optics, the adaptive optic feedback loop, and the frequency converter. These calculations allow nearfield and farfield predictions in good agreement with measurements.
Computer Modeling for Optical Waveguide Sensors.
1987-12-15
COSATI CODES 18 SUBJECT TERMS (Continue on reverse it necessary and cleritify by DIock numnerl FIEL GRUP SB-GOUP Optical waveguide sensors Computer...reflection. The resultant probe beam transmission may be plotted as a function of changes in the refractive index of the surrounding fluid medium. BASIC...all angles of incidence about the critical angle ecr. It should be noted that N in equation (3) is a function of e, since = sin - l sin 8 , see
Optical Turbulence Characterization by WRF model above Ali, Tibet
Wang, Hongshuai; Yao, Yongqiang; Liu, Liyong; Qian, Xuan; Yin, Jia
2015-04-01
Atmospheric optical turbulence modeling and forecast for astronomy is a relatively recent discipline, but has played important roles in site survey, optimization of large telescope observing tables, and in the applications of adaptive optics technique. The numerical approach, by using of meteorological parameters and parameterization of optical turbulence, can provide all the optical turbulence parameters related, such as C2n profile, coherent length, wavefront coherent time, seeing, isoplanatic angle, and so on. This is particularly interesting for searching new sites without the long and expensive site testing campaigns with instruments. Earlier site survey results by the site survey team of National Astronomical Observatories of China imply that the south-west Tibet, Ali, is one of the world best IR and sub-mm site. For searching the best site in Ali area, numerical approach by Weather and Research Forecasting (WRF) model had been used to evaluate the climatology of the optical turbulence. The WRF model is configured over a domain 200km×200km with 1km horizontal resolution and 65 vertical levels from ground to the model top(10millibars) in 2010. The initial and boundary conditions for the model are provided by the 1° × 1° Global Final Analysis data from NCEP. The distribution and seasonal variation of optical turbulence parameters over this area are presented.
Energy dependence of hadron polarization in $e^+e^-\\to hX$ at high energies
Chen, Kai-bao; Zhou, Ya-jin; Liang, Zuo-tang
2016-01-01
The longitudinal polarization of hyperons in $e^+e^-$ annihilation at high energies depends on the longitudinal polarization of the quark produced at the $e^+e^-$ annihilation vertex whereas the spin alignment of vector mesons is independent of it. They exhibit very much different energy dependences. We use the longitudinal polarization of the Lambda hyperon and the spin alignment of $K^*$ as examples and present numerical results of energy dependences. We present the results at the leading twist with perturbative QCD evolutions of fragmentation functions at the leading order.
An electrical model of VCSEL as optical transmitter for optical printed circuit board
Kim, Do-Kyoon; Yoon, Young-Seol; Choi, Jin-Ho; Kim, Kyung-Min; Choi, Young-Wan; Lee, Seok
2005-03-01
Optical interconnection is recent issue for high-speed data transmission. The limitation of high-speed electrical data transmission is caused by impedance mismatching, electric field coupling, microwave loss, and different length of the electrical signal lines. To overcome these limitations, the electrical signal in the current electrical system has to be changed by the optical signal. The most suitable optical source in the OPCB (Optical Printed Circuit Board) is VCSEL (Vertical Cavity Surface Emitting Lasers) that is low-priced and has the characteristic of vertical surface emitting. In this paper, we propose an electrical model of the VCSEL as E/O converting devices for the OPCB. The equivalent circuit of the VCSEL based on the rate equations includes carrier dynamics and material properties. The rate equation parameters are obtained by full analysis based on rate equation and experiment results. The electrical model of the VCSEL has the series resistance determined by I-V characteristic curve, and the parallel capacitance by the parasitic response of the VCSEL chip. The bandwidth of the optical interconnection is analyzed considering those parameters. We design and fabricate the optical transmitter for OPCB considering proposed electrical model of VCSEL.
Mass and energy dependence of pion-induced fission
Peterson, R. J.; Debarros, S.; Desouza, I. O.; Gaspar, M. B.; Khan, Hameed Ahmed; Manzoor, Shahid
1995-06-01
Data for fission induced by pi meson beams from 80 to 500 MeV are presented for nuclei from Fe through Pu as measured by solid state track detectors. The general trends for binary fission with π + are reproduced fairly well by a calculation in the ‘high excitation’ limit with standard level density and fission barrier parameters, but π - data are underpredicted. A universal dependence of the binary fission probabilities with the fissility ( Z±1)2/A is found to be valid for both pion beam charges for all beam energies below the delta resonance. Probabilities for observing three fragments with π + are not reproduced by a ternary fission application of the model found to work for binary fission.
Detecting energy dependent neutron capture distributions in a liquid scintillator
Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)
2015-03-11
A novel technique is being developed to estimate the effective dose of a neutron field based on the distribution of neutron captures in a scintillator. Using Monte Carlo techniques, a number of monoenergetic neutron source energies and locations were modelled and their neutron capture response was recorded. Using back propagation Artificial Neural Networks (ANN) the energy and incident direction of the neutron field was predicted from the distribution of neutron captures within a {sup 6}Li-loaded liquid scintillator. Using this proposed technique, the effective dose of {sup 252}Cf, {sup 241}AmBe and {sup 241}AmLi neutron fields was estimated to within 30% for four perpendicular angles in the horizontal plane. Initial theoretical investigations show that this technique holds some promise for real-time estimation of the effective dose of a neutron field.
Modeling of Nonlinear Signal Distortion in Fiber-Optical Networks
Johannisson, Pontus
2013-01-01
A low-complexity model for signal quality prediction in a nonlinear fiber-optical network is developed. The model, which builds on the Gaussian noise model, takes into account the signal degradation caused by a combination of chromatic dispersion, nonlinear signal distortion, and amplifier noise. The center frequencies, bandwidths, and transmit powers can be chosen independently for each channel, which makes the model suitable for analysis and optimization of resource allocation, routing, and scheduling in large-scale optical networks applying flexible-grid wavelength-division multiplexing.
Photonic encryption : modeling and functional analysis of all optical logic.
Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.
2004-10-01
With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple
System and Energy Dependence of Strangeness Production with STAR
Salur, S
2006-01-01
The yields and spectra of strange hadrons have each been measured by STAR as a function of centrality in $\\rm \\sqrt{s_{NN}}=$ 200 GeV AuAu collisions. By comparison to measurements in pp and dAu at $\\rm \\sqrt{s_{NN}}=200$ GeV and in AuAu at $\\rm \\sqrt{s_{NN}}=62$ GeV the dependence on system size and energy is studied. Short-lived resonances, such as $\\Sigma (1385)$ and $\\Lambda (1520)$, that may decay and regenerate in the medium, are used to examine the dynamical evolution between production and freeze-out for these systems. Particle production is investigated by comparison to thermal models, which assume a simple scaling of the yield with $\\rm N_{part}$, in order to calculate the strangeness enhancement. Our hyperon measurements in AuAu indicate that $\\rm N_{bin}$ may be a more appropriate scale for the strangeness correlation volume. In this case canonical suppression can not be simply parameterized with the geometrical overlap volume but will depend on the individual quark content of each particle. This ...
The Energy-Dependent Position of the IBEX Ribbon Due to the Solar Wind Structure
Swaczyna, Paweł; Bzowski, Maciej; Sokół, Justyna M.
2016-08-01
Observations of energetic neutral atoms (ENAs) allow for remote studies of the condition of plasma in the heliosphere and the neighboring local interstellar medium. The first results from the Interstellar Boundary Explorer (IBEX) revealed an arc-like enhancement of the ENA intensity in the sky, known as the ribbon. The ribbon was not expected from the heliospheric models prior to the launch of IBEX. One proposed explanation for the ribbon is the mechanism of secondary ENA emission. The ribbon reveals energy-dependent structure in the relative intensity along its circumference and in its position. That is, the geometric center of the ribbon varies systematically by about 10° in the energy range 0.7-4.3 keV. Here, we show by analytical modeling that this effect is a consequence of the helio-latitudinal structure of the solar wind reflected in the secondary ENAs. Along with a recently measured distance to the ribbon’s source just beyond the heliopause, our findings support the connection of the ribbon with the local interstellar magnetic field by the mechanism of secondary ENA emission. However, the magnitude of the center shift in the highest IBEX energy channel is much larger in the observations than expected from the modeling. This may be due to another, not currently recognized, process of ENA generation.
Modelling of new generation plasma optical devices
Litovko Irina V.
2016-06-01
Full Text Available The paper presents new generation plasma optical devices based on the electrostatic plasma lens configuration that opens a novel attractive possibility for effective high-tech practical applications. Original approaches to use of plasma accelerators with closed electron drift and open walls for the creation of a cost-effective low-maintenance plasma lens with positive space charge and possible application for low-cost, low-energy rocket engine are described. The preliminary experimental, theoretical and simulation results are presented. It is noted that the presented plasma devices are attractive for many different applications in the state-of-the-art vacuum-plasma processing.
Modeling Coastal Ocean Optical Properties for Coupled Circulation and Ecosystem Models
2016-06-07
Modeling Coastal Ocean Optical Properties for Coupled Circulation and Ecosystem Models Curtis D. Mobley Sequoia Scientific , Inc. 2700 Richards...N00014D01610002 http://www.onr.navy.mil/sci_tech/32/322/ocean_optics_biology.asp LONG-TERM GOAL The overall goal of this work , now completed, was to...wrong by orders of magnitude in Case 2 or optically shallow waters. The objective of this work was develop a radiative transfer model that can be
Ray-tracing optical modeling of negative dysphotopsia
Hong, Xin; Liu, Yueai; Karakelle, Mutlu; Masket, Samuel; Fram, Nicole R.
2011-12-01
Negative dysphotopsia is a relatively common photic phenomenon that may occur after implantation of an intraocular lens. The etiology of negative dysphotopsia is not fully understood. In this investigation, optical modeling was developed using nonsequential-component Zemax ray-tracing technology to simulate photic phenomena experienced by the human eye. The simulation investigated the effects of pupil size, capsulorrhexis size, and bag diffusiveness. Results demonstrated the optical basis of negative dysphotopsia. We found that photic structures were mainly influenced by critical factors such as the capsulorrhexis size and the optical diffusiveness of the capsular bag. The simulations suggested the hypothesis that the anterior capsulorrhexis interacting with intraocular lens could induce negative dysphotopsia.
Photon energy dependence of photo-induced inverse spin-Hall effect in Pt/GaAs and Pt/Ge
Isella, Giovanni, E-mail: giovanni.isella@polimi.it; Bottegoni, Federico; Ferrari, Alberto; Finazzi, Marco; Ciccacci, Franco [LNESS-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)
2015-06-08
We report the photon energy dependence of photo-induced inverse spin Hall effect (ISHE) in Pt/GaAs and Pt/Ge Schottky junctions. The experimental results are compared with a spin drift-diffusion model, which highlights the role played by the different spin lifetime in the two semiconductors, in determining the energy dependence of the ISHE signal detected in the Pt layer. The good qualitative agreement between experiments and modelling indicates that photo-induced ISHE can be used as a tool to characterize spin lifetime in semiconductors.
Yajie Jiang
2015-06-01
Full Text Available The optical properties of perovskites at ambient temperatures are important both to the design of optimised solar cells as well as in other areas such as the refinement of electronic band structure calculations. Limited previous information on the optical modelling has been published. The experimental fitting parameters for optical constants of CH3NH3PbI3−xClx and CH3NH3PbI3 perovskite films are reported at 297 K as determined by detailed analysis of reflectance and transmittance data. The data in this study is related to the research article “Room temperature optical properties of organic–inorganic lead halide perovskites” in Solar Energy Materials & Solar Cells [1].
Optical characterisation of nanostructures using a discretised forward model
Karamehmedovic, Mirza; Sørensen, Mads Peter; Hansen, Poul-Erik
2012-01-01
Optical diffraction microscopy (ODM) is a non-destructive and relatively inexpensive means of characterisation of nanostructures. It is an essential tool in the design, production and quality control of functional nanomaterials. In ODM, the target is reconstructed from the measured optical power...... problem. Finally, the size of the measured nanostructure is typically comparable to the wavelength of the illuminating light, so the scattering needs to be described using the full Maxwellian electromagnetic model, rather than (numerically inexpensive) asymptotic formulations. We here describe...
Eikonal solutions to optical model coupled-channel equations
Cucinotta, Francis A.; Khandelwal, Govind S.; Maung, Khin M.; Townsend, Lawrence W.; Wilson, John W.
1988-01-01
Methods of solution are presented for the Eikonal form of the nucleus-nucleus coupled-channel scattering amplitudes. Analytic solutions are obtained for the second-order optical potential for elastic scattering. A numerical comparison is made between the first and second order optical model solutions for elastic and inelastic scattering of H-1 and He-4 on C-12. The effects of bound-state excitations on total and reaction cross sections are also estimated.
Spinless relativistic particle in energy-dependent potential and normalization of the wave function
Benchikha, Amar; Chetouani, Lyazid
2014-06-01
The problem of normalization related to a Klein-Gordon particle subjected to vector plus scalar energy-dependent potentials is clarified in the context of the path integral approach. In addition the correction relating to the normalizing constant of wave functions is exactly determined. As examples, the energy dependent linear and Coulomb potentials are considered. The wave functions obtained via spectral decomposition, were found exactly normalized.
Inter-dependence not Over-dependence: Reducing Urban Transport Energy Dependence
Saunders, Michael James; Rodrigues da Silva, Antonio Nelson
2007-07-01
A major issue of concern in today's world is urban transport energy dependence and energy supply security. In an energy inter-dependent world, energy over-dependence brings risks to urban transport systems. Many urban areas are over-dependent on finite petroleum resources for transport. New technology and the development and integration of renewable resources into transport energy systems may reduce some of the current transport energy dependence of urban areas. However, the most effective means of reducing energy dependence is to first design urban areas for this condition. An urban policy framework is proposed that requires transport energy dependence to be measured and controlled in the urban development process. A new tool has been created for this purpose, the Transport Energy Specification (TES), which measures transport energy dependence of urban areas. This creates the possibility for cities to regulate urban development with respect to energy dependence. Trial assessments were performed in Germany, New Zealand and Brazil; initial analysis by transport and government professionals shows promise of this tool being included into urban policy. The TES combined with a regulatory framework has the potential to significantly reduce transport energy consumption and dependence in urban areas in the future. (auth)
Event-Based Corpuscular Model for Quantum Optics Experiments
Michielsen, K.; Jin, F.; Raedt, H. De
2011-01-01
A corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one is presented. The event-based corpuscular model is shown to give a u
Event-Based Corpuscular Model for Quantum Optics Experiments
Michielsen, K.; Jin, F.; Raedt, H. De
A corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one is presented. The event-based corpuscular model is shown to give a
Event-based Simulation Model for Quantum Optics Experiments
De Raedt, H.; Michielsen, K.; Jaeger, G; Khrennikov, A; Schlosshauer, M; Weihs, G
2011-01-01
We present a corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one. The event-based corpuscular model gives a unified
Optical linear algebra processors: noise and error-source modeling.
Casasent, D; Ghosh, A
1985-06-01
The modeling of system and component noise and error sources in optical linear algebra processors (OLAP's) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.
Optical linear algebra processors - Noise and error-source modeling
Casasent, D.; Ghosh, A.
1985-01-01
The modeling of system and component noise and error sources in optical linear algebra processors (OLAPs) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.
Integrating Environmental Optics into Multidisciplinary, Predictive Models of Ocean Dynamics
2011-09-30
development has been based on decades of published research, our depth-integrated, spectral model of photosynthesis and the absorption -based model of...color, chlorophyll fluorescence, or spectral absorption coefficients. We extend the approach to include additional biological properties such as...of laboratory experiments in which photosynthesis , fluorescence and optical properties of phytoplankton are measured under a range of conditions
Extended Hubbard models for ultracold atoms in optical lattices
Juergensen, Ole
2015-06-05
In this thesis, the phase diagrams and dynamics of various extended Hubbard models for ultracold atoms in optical lattices are studied. Hubbard models are the primary description for many interacting particles in periodic potentials with the paramount example of the electrons in solids. The very same models describe the behavior of ultracold quantum gases trapped in the periodic potentials generated by interfering beams of laser light. These optical lattices provide an unprecedented access to the fundamentals of the many-particle physics that govern the properties of solid-state materials. They can be used to simulate solid-state systems and validate the approximations and simplifications made in theoretical models. This thesis revisits the numerous approximations underlying the standard Hubbard models with special regard to optical lattice experiments. The incorporation of the interaction between particles on adjacent lattice sites leads to extended Hubbard models. Offsite interactions have a strong influence on the phase boundaries and can give rise to novel correlated quantum phases. The extended models are studied with the numerical methods of exact diagonalization and time evolution, a cluster Gutzwiller approximation, as well as with the strong-coupling expansion approach. In total, this thesis demonstrates the high relevance of beyond-Hubbard processes for ultracold atoms in optical lattices. Extended Hubbard models can be employed to tackle unexplained problems of solid-state physics as well as enter previously inaccessible regimes.
PET energy-based scatter estimation and image reconstruction with energy-dependent corrections
Popescu, L M; Lewitt, Robert M; Matej, Samuel; Karp, Joel S [Department of Radiology, University of Pennsylvania, 423 Guardian Drive, 4th floor Blockley Hall, Philadelphia, PA 19104-6021 (United States)
2006-06-07
In this paper we propose a comprehensive energy-based scatter correction approach for positron emission tomography (PET). We take advantage of the marked difference between the energy spectra of the unscattered and scattered photons, and use the detailed energy information that comes with the list-mode data for the estimation of the scattered events distribution in the data space. Also, inside the maximum-likelihood expectation maximization (ML-EM) image reconstruction algorithm, we introduce energy-dependent factors that individualize the correction terms for each event, given its position and energy information. The central piece of our approach is the two-dimensional detector energy response model represented as a linear combination of four components, each one representing a particular state a PET event can be found in: both photons unscattered, the second scattered while the first not, the first photon scattered while the second not and both photons scattered. For a set of events collected in the vicinity of a point in the projection space, the coefficient of each component is determined by applying a statistical estimator. As a result we obtain the number of scattered events that are in the given set. The model also gives us the variation of scatter fraction with the photon pair energies for that particular position in the data space. A simulation study that demonstrates the proposed methods is presented.
Study of the energy dependence of the underlying event in proton-antiproton collisions
Aaltonen, T.; Albrow, M.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; D'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Galloni, C.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lucá, A.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Marchese, L.; Margaroli, F.; Marino, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Song, H.; Sorin, V.; St. Denis, R.; Stancari, M.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vázquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizán, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S. M.; Waters, D.; Wester, W. C.; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Zanetti, A. M.; Zeng, Y.; Zhou, C.; Zucchelli, S.; CDF Collaboration
2015-11-01
We study charged particle production (pT>0.5 GeV /c , |η |<0.8 ) in proton-antiproton collisions at total center-of-mass energies √{s }=300 GeV , 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of η -ϕ space: "toward", "away", and "transverse." The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the "underlying event." The transverse region is divided into a MAX and MIN transverse region, which helps separate the "hard component" (initial and final-state radiation) from the "beam-beam remnant" and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event is studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.
The energy-dependent position of the IBEX ribbon due to the solar wind structure
Swaczyna, Paweł; Sokół, Justyna M
2016-01-01
Observations of energetic neutral atoms (ENAs) allow for remote studies of the plasma condition in the heliosphere and the neighboring local interstellar medium. The first IBEX results revealed an arc-like enhancement of the ENA flux in the sky, known as the ribbon. The ribbon was not expected from the heliospheric models prior to the IBEX launch. One of the proposed explanations of the ribbon is the mechanism of the secondary ENA emission. The ribbon reveals energy-dependent structure in the relative intensity along its circumference and in the position. Namely, the ribbon geometric center varies systematically by about 10$^\\circ$ in the energy range 0.7-4.3 keV. Here, we show by analytic modeling that this effect is a consequence of the helio-latitudinal structure of the solar wind reflected in the secondary ENAs. Along with a recently measured distance to the ribbon source just beyond the heliopause, our findings support the connection of the ribbon with the local interstellar magnetic field by the mechani...
Energy dependence of multiplicity fluctuations in heavy ion collisions at the CERN SPS
Lungwitz, Benjamin
2008-01-01
In this work data of the NA49 experiment at CERN SPS on the energy dependence of multiplicity fluctuations in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV, as well as the system size dependence at 158A GeV, is analysed for positively, negatively and all charged hadrons. Furthermore the rapidity and transverse momentum dependence of multiplicity fluctuations are studied. The experimental results are compared to predictions of statistical hadron-gas and string-hadronic models. It is expected that multiplicity fluctuations are sensitive to the phase transition to quark-gluon-plasma (QGP) and to the critical point of strongly interacting matter. It is predicted that both the onset of deconfinement, the lowest energy where QGP is created, and the critical point are located in the SPS energy range. Furthermore, the predictions for the multiplicity fluctuations of statistical and string-hadronic models are different, the experimental data might allow to distinguish between them. The used measure of mu...
A Study of the Energy Dependence of the Underlying Event in Proton-Antiproton Collisions
Aaltonen, Timo Antero; Amerio, Silvia; Amidei, Dante E; Anastassov, Anton Iankov; Annovi, Alberto; Antos, Jaroslav; Apollinari, Giorgio; Appel, Jeffrey A; Arisawa, Tetsuo; Artikov, Akram Muzafarovich; Asaadi, Jonathan A; Ashmanskas, William Joseph; Auerbach, Benjamin; Aurisano, Adam J; Azfar, Farrukh A; Badgett, William Farris; Bae, Taegil; Barbaro-Galtieri, Angela; Barnes, Virgil E; Barnett, Bruce Arnold; Barria, Patrizia; Bartos, Pavol; Bauce, Matteo; Bedeschi, Franco; Behari, Satyajit; Bellettini, Giorgio; Bellinger, James Nugent; Benjamin, Douglas P; Beretvas, Andrew F; Bhatti, Anwar Ahmad; Bland, Karen Renee; Blumenfeld, Barry J; Bocci, Andrea; Bodek, Arie; Bortoletto, Daniela; Boudreau, Joseph Francis; Boveia, Antonio; Brigliadori, Luca; Bromberg, Carl Michael; Brucken, Erik; Budagov, Ioulian A; Budd, Howard Scott; Burkett, Kevin Alan; Busetto, Giovanni; Bussey, Peter John; Butti, Pierfrancesco; Buzatu, Adrian; Calamba, Aristotle; Camarda, Stefano; Campanelli, Mario; Canelli, Florencia; Carls, Benjamin; Carlsmith, Duncan L; Carosi, Roberto; Carrillo Moreno, Salvador; Casal Larana, Bruno; Casarsa, Massimo; Castro, Andrea; Catastini, Pierluigi; Cauz, Diego; Cavaliere, Viviana; Cerri, Alessandro; Cerrito, Lucio; Chen, Yen-Chu; Chertok, Maxwell Benjamin; Chiarelli, Giorgio; Chlachidze, Gouram; Cho, Kihyeon; Chokheli, Davit; Clark, Allan Geoffrey; Clarke, Christopher Joseph; Convery, Mary Elizabeth; Conway, John Stephen; Corbo, Matteo; Cordelli, Marco; Cox, Charles Alexander; Cox, David Jeremy; Cremonesi, Matteo; Cruz Alonso, Daniel; Cuevas Maestro, Javier; Culbertson, Raymond Lloyd; D'Ascenzo, Nicola; Datta, Mousumi; de Barbaro, Pawel; Demortier, Luc M; Marchese, Luigi Marchese; Deninno, Maria Maddalena; Devoto, Francesco; D'Errico, Maria; Di Canto, Angelo; Di Ruzza, Benedetto; Dittmann, Jay Richard; D'Onofrio, Monica; Donati, Simone; Dorigo, Mirco; Driutti, Anna; Ebina, Koji; Edgar, Ryan Christopher; Erbacher, Robin D; Errede, Steven Michael; Esham, Benjamin; Farrington, Sinead Marie; Fernández Ramos, Juan Pablo; Field, Richard D; Flanagan, Gene U; Forrest, Robert David; Franklin, Melissa EB; Freeman, John Christian; Frisch, Henry J; Funakoshi, Yujiro; Galloni, Camilla; Garfinkel, Arthur F; Garosi, Paola; Gerberich, Heather Kay; Gerchtein, Elena A; Giagu, Stefano; Giakoumopoulou, Viktoria Athina; Gibson, Karen Ruth; Ginsburg, Camille Marie; Giokaris, Nikos D; Giromini, Paolo; Glagolev, Vladimir; Glenzinski, Douglas Andrew; Gold, Michael S; Goldin, Daniel; Golossanov, Alexander; Gomez, Gervasio; Gomez-Ceballos, Guillelmo; Goncharov, Maxim T; González López, Oscar; Gorelov, Igor V; Goshaw, Alfred T; Goulianos, Konstantin A; Gramellini, Elena; Grosso-Pilcher, Carla; Guimaraes da Costa, Joao; Hahn, Stephen R; Han, Ji-Yeon; Happacher, Fabio; Hara, Kazuhiko; Hare, Matthew Frederick; Harr, Robert Francis; Harrington-Taber, Timothy; Hatakeyama, Kenichi; Hays, Christopher Paul; Heinrich, Joel G; Herndon, Matthew Fairbanks; Hocker, James Andrew; Hong, Ziqing; Hopkins, Walter Howard; Hou, Suen Ray; Hughes, Richard Edward; Husemann, Ulrich; Hussein, Mohammad; Huston, Joey Walter; Introzzi, Gianluca; Iori, Maurizio; Ivanov, Andrew Gennadievich; James, Eric B; Jang, Dongwook; Jayatilaka, Bodhitha Anjalike; Jeon, Eun-Ju; Jindariani, Sergo Robert; Jones, Matthew T; Joo, Kyung Kwang; Jun, Soon Yung; Junk, Thomas R; Kambeitz, Manuel; Kamon, Teruki; Karchin, Paul Edmund; Kasmi, Azeddine; Kato, Yukihiro; Ketchum, Wesley Robert; Keung, Justin Kien; Kilminster, Benjamin John; Kim, DongHee; Kim, Hyunsoo; Kim, Jieun; Kim, Min Jeong; Kim, Soo Bong; Kim, Shin-Hong; Kim, Young-Kee; Kim, Young-Jin; Kimura, Naoki; Kirby, Michael H; Knoepfel, Kyle James; Kondo, Kunitaka; Kong, Dae Jung; Konigsberg, Jacobo; Kotwal, Ashutosh Vijay; Kreps, Michal; Kroll, IJoseph; Kruse, Mark Charles; Kuhr, Thomas; Kurata, Masakazu; Laasanen, Alvin Toivo; Lammel, Stephan; Lancaster, Mark; Lannon, Kevin Patrick; Latino, Giuseppe; Lee, Hyun Su; Lee, Jaison; Leo, Sabato; Leone, Sandra; Lewis, Jonathan D; Limosani, Antonio; Lipeles, Elliot David; Lister, Alison; Liu, Qiuguang; Liu, Tiehui Ted; Lockwitz, Sarah E; Loginov, Andrey Borisovich; Lucà, Alessandra; Lucchesi, Donatella; Lueck, Jan; Lujan, Paul Joseph; Lukens, Patrick Thomas; Lungu, Gheorghe; Lys, Jeremy E; Lysak, Roman; Madrak, Robyn Leigh; Maestro, Paolo; Malik, Sarah Alam; Manca, Giulia; Manousakis-Katsikakis, Arkadios; Margaroli, Fabrizio; Marino, Christopher Phillip; Matera, Keith; Mattson, Mark Edward; Mazzacane, Anna; Mazzanti, Paolo; McNulty, Ronan; Mehta, Andrew; Mehtala, Petteri; Mesropian, Christina; Miao, Ting; Mietlicki, David John; Mitra, Ankush; Miyake, Hideki; Moed, Shulamit; Moggi, Niccolo; Moon, Chang-Seong; Moore, Ronald Scott; Morello, Michael Joseph; Mukherjee, Aseet; Muller, Thomas; Murat, Pavel A; Mussini, Manuel; Nachtman, Jane Marie; Nagai, Yoshikazu; Naganoma, Junji; Nakano, Itsuo; Napier, Austin; Nett, Jason Michael; Nigmanov, Turgun S; Nodulman, Lawrence J; Noh, Seoyoung; Norniella Francisco, Olga; Oakes, Louise Beth; Oh, Seog Hwan; Oh, Young-do; Okusawa, Toru; Orava, Risto Olavi; Ortolan, Lorenzo; Pagliarone, Carmine Elvezio; Palencia, Jose Enrique; Palni, Prabhakar; Papadimitriou, Vaia; Parker, William Chesluk; Pauletta, Giovanni; Paulini, Manfred; Paus, Christoph Maria Ernst; Phillips, Thomas J; Piacentino, Giovanni M; Pianori, Elisabetta; Pilot, Justin Robert; Pitts, Kevin T; Plager, Charles; Pondrom, Lee G; Poprocki, Stephen; Potamianos, Karolos Jozef; Prokoshin, Fedor; Pranko, Aliaksandr Pavlovich; Ptohos, Fotios K; Punzi, Giovanni; Redondo Fernández, Ignacio; Renton, Peter B; Rescigno, Marco; Rimondi, Franco; Ristori, Luciano; Robson, Aidan; Rodriguez, Tatiana Isabel; Rolli, Simona; Ronzani, Manfredi; Roser, Robert Martin; Rosner, Jonathan L; Ruffini, Fabrizio; Ruiz Jimeno, Alberto; Russ, James S; Rusu, Vadim Liviu; Sakumoto, Willis Kazuo; Sakurai, Yuki; Santi, Lorenzo; Sato, Koji; Saveliev, Valeri; Savoy-Navarro, Aurore; Schlabach, Philip; Schmidt, Eugene E; Schwarz, Thomas A; Scodellaro, Luca; Scuri, Fabrizio; Seidel, Sally C; Seiya, Yoshihiro; Semenov, Alexei; Sforza, Federico; Shalhout, Shalhout Zaki; Shears, Tara G; Shepard, Paul F; Shimojima, Makoto; Shochet, Melvyn J; Shreyber-Tecker, Irina; Simonenko, Alexander V; Sliwa, Krzysztof Jan; Smith, John Rodgers; Snider, Frederick Douglas; Sorin, Maria Veronica; Song, Hao; Stancari, Michelle Dawn; St Denis, Richard Dante; Stentz, Dale James; Strologas, John; Sudo, Yuji; Sukhanov, Alexander I; Suslov, Igor M; Takemasa, Ken-ichi; Takeuchi, Yuji; Tang, Jian; Tecchio, Monica; Teng, Ping-Kun; Thom, Julia; Thomson, Evelyn Jean; Thukral, Vaikunth; Toback, David A; Tokar, Stanislav; Tollefson, Kirsten Anne; Tomura, Tomonobu; Tonelli, Diego; Torre, Stefano; Torretta, Donatella; Totaro, Pierluigi; Trovato, Marco; Ukegawa, Fumihiko; Uozumi, Satoru; Vázquez-Valencia, Elsa Fabiola; Velev, Gueorgui; Vellidis, Konstantinos; Vernieri, Caterina; Vidal Marono, Miguel; Vilar Cortabitarte, Rocio; Vizán Garcia, Jesus Manuel; Vogel, Marcelo; Volpi, Guido; Wagner, Peter; Wallny, Rainer S; Wang, Song-Ming; Waters, David S; Wester, William Carl; Whiteson, Daniel O; Wicklund, Arthur Barry; Wilbur, Scott; Williams, Hugh H; Wilson, Jonathan Samuel; Wilson, Peter James; Winer, Brian L; Wittich, Peter; Wolbers, Stephen A; Wolfe, Homer; Wright, Thomas Roland; Wu, Xin; Wu, Zhenbin; Yamamoto, Kazuhiro; Yamato, Daisuke; Yang, Tingjun; Yang, Un-Ki; Yang, Yu Chul; Yao, Wei-Ming; Yeh, Gong Ping; Yi, Kai; Yoh, John; Yorita, Kohei; Yoshida, Takuo; Yu, Geum Bong; Yu, Intae; Zanetti, Anna Maria; Zeng, Yu; Zhou, Chen; Zucchelli, Stefano
2015-01-01
We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.
Study of the energy dependence of the underlying event in proton-antiproton collisions
Nodulman, L.; Aaltonen, T; Albrow, M; Amerio, S.; Amidei, D; Anastassov, A.; Annovi, A; Antos, J; Apollinari, G.; Appel, J A; Arisawa, T
2015-11-23
We study charged particle production (p(T) > 0.5 GeV/c, vertical bar eta vertical bar < 0.8) in proton-antiproton collisions at total center-of-mass energies root s = 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta - phi space: "toward", "away", and "transverse." The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the "underlying event." The transverse region is divided into a MAX and MIN transverse region, which helps separate the "hard component" (initial and final-state radiation) from the "beam-beam remnant" and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event is studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.
A Study of the Energy Dependence of the Underlying Event in Proton-Antiproton Collisions
Aaltonen, Timo Antero; Amidei, Dante E; Anastassov, Anton Iankov; Annovi, Alberto; Antos, Jaroslav; Apollinari, Giorgio; Appel, Jeffrey A; Arisawa, Tetsuo; Artikov, Akram Muzafarovich; Asaadi, Jonathan A; Ashmanskas, William Joseph; Auerbach, Benjamin; Aurisano, Adam J; Azfar, Farrukh A; Badgett, William Farris; Bae, Taegil; Barbaro-Galtieri, Angela; Barnes, Virgil E; Barnett, Bruce Arnold; Barria, Patrizia; Bartos, Pavol; Bauce, Matteo; Bedeschi, Franco; Behari, Satyajit; Bellettini, Giorgio; Bellinger, James Nugent; Benjamin, Douglas P; Beretvas, Andrew F; Bhatti, Anwar Ahmad; Bland, Karen Renee; Blumenfeld, Barry J; Bocci, Andrea; Bodek, Arie; Bortoletto, Daniela; Boudreau, Joseph Francis; Boveia, Antonio; Brigliadori, Luca; Bromberg, Carl Michael; Brucken, Erik; Budagov, Ioulian A; Budd, Howard Scott; Burkett, Kevin Alan; Busetto, Giovanni; Bussey, Peter John; Butti, Pierfrancesco; Buzatu, Adrian; Calamba, Aristotle; Camarda, Stefano; Campanelli, Mario; Canelli, Florencia; Carls, Benjamin; Carlsmith, Duncan L; Carosi, Roberto; Carrillo Moreno, Salvador; Casal Larana, Bruno; Casarsa, Massimo; Castro, Andrea; Catastini, Pierluigi; Cauz, Diego; Cavaliere, Viviana; Cerri, Alessandro; Cerrito, Lucio; Chen, Yen-Chu; Chertok, Maxwell Benjamin; Chiarelli, Giorgio; Chlachidze, Gouram; Cho, Kihyeon; Chokheli, Davit; Clark, Allan Geoffrey; Clarke, Christopher Joseph; Convery, Mary Elizabeth; Conway, John Stephen; Corbo, Matteo; Cordelli, Marco; Cox, Charles Alexander; Cox, David Jeremy; Cremonesi, Matteo; Cruz Alonso, Daniel; Cuevas Maestro, Javier; Culbertson, Raymond Lloyd; D'Ascenzo, Nicola; Datta, Mousumi; de Barbaro, Pawel; Demortier, Luc M; Marchese, Luigi; Deninno, Maria Maddalena; Devoto, Francesco; D'Errico, Maria; Di Canto, Angelo; Di Ruzza, Benedetto; Dittmann, Jay Richard; D'Onofrio, Monica; Donati, Simone; Dorigo, Mirco; Driutti, Anna; Ebina, Koji; Edgar, Ryan Christopher; Erbacher, Robin D; Errede, Steven Michael; Esham, Benjamin; Farrington, Sinead Marie; Fernández Ramos, Juan Pablo; Field, Richard D; Flanagan, Gene U; Forrest, Robert David; Franklin, Melissa EB; Freeman, John Christian; Frisch, Henry J; Funakoshi, Yujiro; Galloni, Camilla; Garfinkel, Arthur F; Garosi, Paola; Gerberich, Heather Kay; Gerchtein, Elena A; Giagu, Stefano; Giakoumopoulou, Viktoria Athina; Gibson, Karen Ruth; Ginsburg, Camille Marie; Giokaris, Nikos D; Giromini, Paolo; Glagolev, Vladimir; Glenzinski, Douglas Andrew; Gold, Michael S; Goldin, Daniel; Golossanov, Alexander; Gomez, Gervasio; Gomez-Ceballos, Guillelmo; Goncharov, Maxim T; González López, Oscar; Gorelov, Igor V; Goshaw, Alfred T; Goulianos, Konstantin A; Gramellini, Elena; Grosso-Pilcher, Carla; Guimaraes da Costa, Joao; Hahn, Stephen R; Han, Ji-Yeon; Happacher, Fabio; Hara, Kazuhiko; Hare, Matthew Frederick; Harr, Robert Francis; Harrington-Taber, Timothy; Hatakeyama, Kenichi; Hays, Christopher Paul; Heinrich, Joel G; Herndon, Matthew Fairbanks; Hocker, James Andrew; Hong, Ziqing; Hopkins, Walter Howard; Hou, Suen Ray; Hughes, Richard Edward; Husemann, Ulrich; Hussein, Mohammad; Huston, Joey Walter; Introzzi, Gianluca; Iori, Maurizio; Ivanov, Andrew Gennadievich; James, Eric B; Jang, Dongwook; Jayatilaka, Bodhitha Anjalike; Jeon, Eun-Ju; Jindariani, Sergo Robert; Jones, Matthew T; Joo, Kyung Kwang; Jun, Soon Yung; Junk, Thomas R; Kambeitz, Manuel; Kamon, Teruki; Karchin, Paul Edmund; Kasmi, Azeddine; Kato, Yukihiro; Ketchum, Wesley Robert; Keung, Justin Kien; Kilminster, Benjamin John; Kim, DongHee; Kim, Hyunsoo; Kim, Jieun; Kim, Min Jeong; Kim, Soo Bong; Kim, Shin-Hong; Kim, Young-Kee; Kim, Young-Jin; Kimura, Naoki; Kirby, Michael H; Knoepfel, Kyle James; Kondo, Kunitaka; Kong, Dae Jung; Konigsberg, Jacobo; Kotwal, Ashutosh Vijay; Kreps, Michal; Kroll, IJoseph; Kruse, Mark Charles; Kuhr, Thomas; Kurata, Masakazu; Laasanen, Alvin Toivo; Lammel, Stephan; Lancaster, Mark; Lannon, Kevin Patrick; Latino, Giuseppe; Lee, Hyun Su; Lee, Jaison; Leo, Sabato; Leone, Sandra; Lewis, Jonathan D; Limosani, Antonio; Lipeles, Elliot David; Lister, Alison; Liu, Qiuguang; Liu, Tiehui Ted; Lockwitz, Sarah E; Loginov, Andrey Borisovich; Lucà, Alessandra; Lucchesi, Donatella; Lueck, Jan; Lujan, Paul Joseph; Lukens, Patrick Thomas; Lungu, Gheorghe; Lys, Jeremy E; Lysak, Roman; Madrak, Robyn Leigh; Maestro, Paolo; Malik, Sarah Alam; Manca, Giulia; Manousakis-Katsikakis, Arkadios; Margaroli, Fabrizio; Marino, Christopher Phillip; Matera, Keith; Mattson, Mark Edward; Mazzacane, Anna; Mazzanti, Paolo; McNulty, Ronan; Mehta, Andrew; Mehtala, Petteri; Mesropian, Christina; Miao, Ting; Mietlicki, David John; Mitra, Ankush; Miyake, Hideki; Moed, Shulamit; Moggi, Niccolo; Moon, Chang-Seong; Moore, Ronald Scott; Morello, Michael Joseph; Mukherjee, Aseet; Muller, Thomas; Murat, Pavel A; Mussini, Manuel; Nachtman, Jane Marie; Nagai, Yoshikazu; Naganoma, Junji; Nakano, Itsuo; Napier, Austin; Nett, Jason Michael; Nigmanov, Turgun S; Nodulman, Lawrence J; Noh, Seoyoung; Norniella Francisco, Olga; Oakes, Louise Beth; Oh, Seog Hwan; Oh, Young-do; Okusawa, Toru; Orava, Risto Olavi; Ortolan, Lorenzo; Pagliarone, Carmine Elvezio; Palencia, Jose Enrique; Palni, Prabhakar; Papadimitriou, Vaia; Parker, William Chesluk; Pauletta, Giovanni; Paulini, Manfred; Paus, Christoph Maria Ernst; Phillips, Thomas J; Piacentino, Giovanni M; Pianori, Elisabetta; Pilot, Justin Robert; Pitts, Kevin T; Plager, Charles; Pondrom, Lee G; Poprocki, Stephen; Potamianos, Karolos Jozef; Prokoshin, Fedor; Pranko, Aliaksandr Pavlovich; Ptohos, Fotios K; Punzi, Giovanni; Redondo Fernández, Ignacio; Renton, Peter B; Rescigno, Marco; Rimondi, Franco; Ristori, Luciano; Robson, Aidan; Rodriguez, Tatiana Isabel; Rolli, Simona; Ronzani, Manfredi; Roser, Robert Martin; Rosner, Jonathan L; Ruffini, Fabrizio; Ruiz Jimeno, Alberto; Russ, James S; Rusu, Vadim Liviu; Sakumoto, Willis Kazuo; Sakurai, Yuki; Santi, Lorenzo; Sato, Koji; Saveliev, Valeri; Savoy-Navarro, Aurore; Schlabach, Philip; Schmidt, Eugene E; Schwarz, Thomas A; Scodellaro, Luca; Scuri, Fabrizio; Seidel, Sally C; Seiya, Yoshihiro; Semenov, Alexei; Sforza, Federico; Shalhout, Shalhout Zaki; Shears, Tara G; Shepard, Paul F; Shimojima, Makoto; Shochet, Melvyn J; Shreyber-Tecker, Irina; Simonenko, Alexander V; Sliwa, Krzysztof Jan; Smith, John Rodgers; Snider, Frederick Douglas; Sorin, Maria Veronica; Song, Hao; Stancari, Michelle Dawn; St Denis, Richard Dante; Stentz, Dale James; Strologas, John; Sudo, Yuji; Sukhanov, Alexander I; Suslov, Igor M; Takemasa, Ken-ichi; Takeuchi, Yuji; Tang, Jian; Tecchio, Monica; Teng, Ping-Kun; Thom, Julia; Thomson, Evelyn Jean; Thukral, Vaikunth; Toback, David A; Tokar, Stanislav; Tollefson, Kirsten Anne; Tomura, Tomonobu; Tonelli, Diego; Torre, Stefano; Torretta, Donatella; Totaro, Pierluigi; Trovato, Marco; Ukegawa, Fumihiko; Uozumi, Satoru; Vázquez-Valencia, Elsa Fabiola; Velev, Gueorgui; Vellidis, Konstantinos; Vernieri, Caterina; Vidal Marono, Miguel; Vilar Cortabitarte, Rocio; Vizán Garcia, Jesus Manuel; Vogel, Marcelo; Volpi, Guido; Wagner, Peter; Wallny, Rainer S; Wang, Song-Ming; Waters, David S; Wester, William Carl; Whiteson, Daniel O; Wicklund, Arthur Barry; Wilbur, Scott; Williams, Hugh H; Wilson, Jonathan Samuel; Wilson, Peter James; Winer, Brian L; Wittich, Peter; Wolbers, Stephen A; Wolfe, Homer; Wright, Thomas Roland; Wu, Xin; Wu, Zhenbin; Yamamoto, Kazuhiro; Yamato, Daisuke; Yang, Tingjun; Yang, Un-Ki; Yang, Yu Chul; Yao, Wei-Ming; Yeh, Gong Ping; Yi, Kai; Yoh, John; Yorita, Kohei; Yoshida, Takuo; Yu, Geum Bong; Yu, Intae; Zanetti, Anna Maria; Zeng, Yu; Zhou, Chen; Zucchelli, Stefano
2015-11-23
We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.
Numerical model for thermal parameters in optical materials
Sato, Yoichi; Taira, Takunori
2016-04-01
Thermal parameters of optical materials, such as thermal conductivity, thermal expansion, temperature coefficient of refractive index play a decisive role for the thermal design inside laser cavities. Therefore, numerical value of them with temperature dependence is quite important in order to develop the high intense laser oscillator in which optical materials generate excessive heat across mode volumes both of lasing output and optical pumping. We already proposed a novel model of thermal conductivity in various optical materials. Thermal conductivity is a product of isovolumic specific heat and thermal diffusivity, and independent modeling of these two figures should be required from the viewpoint of a clarification of physical meaning. Our numerical model for thermal conductivity requires one material parameter for specific heat and two parameters for thermal diffusivity in the calculation of each optical material. In this work we report thermal conductivities of various optical materials as Y3Al5O12 (YAG), YVO4 (YVO), GdVO4 (GVO), stoichiometric and congruent LiTaO3, synthetic quartz, YAG ceramics and Y2O3 ceramics. The dependence on Nd3+-doping in laser gain media in YAG, YVO and GVO is also studied. This dependence can be described by only additional three parameters. Temperature dependence of thermal expansion and temperature coefficient of refractive index for YAG, YVO, and GVO: these are also included in this work for convenience. We think our numerical model is quite useful for not only thermal analysis in laser cavities or optical waveguides but also the evaluation of physical properties in various transparent materials.
Assimilation of Bio-Optical Properties into Coupled Physical, Bio-Optical Coastal Model
2013-01-01
analysis (updated) fields for the bio-optical model state variables are derived from: Proc. of SPIE Vol. 8724 87240E-3 Downloaded From: http...proceedings.spiedigitallibrary.org/ on 07/11/2013 Terms of Use: http://spiedl.org/terms ),XY(XX fofa HK −+= aX fX oY (1) where is vector of the
Classification of scalar and dyadic nonlocal optical response models.
Wubs, M
2015-11-30
Nonlocal optical response is one of the emerging effects on the nanoscale for particles made of metals or doped semiconductors. Here we classify and compare both scalar and tensorial nonlocal response models. In the latter case the nonlocality can stem from either the longitudinal response, the transverse response, or both. In phenomenological scalar models the nonlocal response is described as a smearing out of the commonly assumed infinitely localized response, as characterized by a distribution with a finite width. Here we calculate explicitly whether and how tensorial models, such as the hydrodynamic Drude model and generalized nonlocal optical response theory, follow this phenomenological description. We find considerable differences, for example that nonlocal response functions, in contrast to simple distributions, assume negative and complex values. Moreover, nonlocal response regularizes some but not all diverging optical near fields. We identify the scalar model that comes closest to the hydrodynamic model. Interestingly, for the hydrodynamic Drude model we find that actually only one third (1/3) of the free-electron response is smeared out nonlocally. In that sense, nonlocal response is stronger for transverse and scalar nonlocal response models, where the smeared-out fractions are 2/3 and 3/3, respectively. The latter two models seem to predict novel plasmonic resonances also below the plasma frequency, in contrast to the hydrodynamic model that predicts standing pressure waves only above the plasma frequency.
Polarization Drift Channel Model for Coherent Fibre-Optic Systems
Czegledi, Cristian B; Agrell, Erik; Johannisson, Pontus
2015-01-01
A theoretical framework is introduced to model the dynamical changes of the state of polarization during transmission in coherent fibre-optic systems. The model generalizes the one-dimensional phase noise random walk to higher dimensions, accounting for random polarization drifts. The model is described in the Jones, Stokes and real 4-dimensional formalisms, and the mapping between them is derived. Such a model will be increasingly important in simulating and optimizing future optical systems, which to a higher and higher degree rely on transmission and detection on both polarizations jointly using sophisticated digital signal processing. Such analysis cannot be carried out using the more rudimentary polarization drift models in use today, which only account for deterministic effects. The proposed polarization drift model is the first of its kind and will likely be useful in a wide-range of photonics applications where stochastic polarization fluctuation is an issue.
Modeling light–tissue interaction in optical coherence tomography systems
Andersen, Peter E.; Jørgensen, Thomas Martini; Thrane, Lars
2015-01-01
Optical coherence tomography (OCT) performs high-resolution, cross-sectional tomographic imaging of the internal tissue microstructure by measuring backscattered or backreflected light. The scope of this chapter is to present analytical and numerical models that are able to describe light......-tissue interactions and its influence on the performance of OCT systems including multiple scattering effects in heterogeneous media. In general, these models, analytical as well as numerical, may serve as important tools for improving interpretation of OCT images and also serve as prerequisites for extraction...... of tissue optical scattering parameters....
Artificial Neural Network Model for Optical Fiber Direction Coupler Design
李九生; 鲍振武
2004-01-01
A new approach to the design of the optical fiber direction coupler by using neural network is proposed. To train the artificial neural network,the coupling length is defined as the input sample, and the coupling ratio is defined as the output sample. Compared with the numerical value calculation of the theoretical formula, the error of the neural network model output is 1% less.Then, through the model, to design a broadband or a single wavelength optical fiber direction coupler becomes easy. The method is proved to be reliable, accurate and time-saving. So it is promising in the field of both investigation and application.
A Fourier Optical Model for the Laser Doppler Velocimeter
Lading, Lars
1972-01-01
The treatment is based on a fourier optical model. It is shown how the various configurations (i.e. ldquodifferential moderdquo and reference beam mode with both one and two incident beams) are incorporated in the model, and how it can be extended to three dimensions. The particles are represented...... filtering ability vanishes as the aperture size converges towards zero. The results based on fourier optics are compared with the rough estimates obtainable by using the "antenna formular" for heterodyning (ArΩr≈λ2)....
Gautam, Manjeet Singh
2015-01-01
In the present work, the fusion of symmetric and asymmetric projectile-target combinations are deeply analyzed within the framework of energy dependent Woods-Saxon potential model (EDWSP model) in conjunction with one dimensional Wong formula and the coupled channel code CCFULL. The neutron transfer channels and the inelastic surface excitations of collision partners are dominating mode of couplings and the coupling of relative motion of colliding nuclei to such relevant internal degrees of freedom produces a significant fusion enhancement at sub-barrier energies. It is quite interesting that the effects of dominant intrinsic degrees of freedom such as multi-phonon vibrational states, neutron transfer channels and proton transfer channels can be simulated by introducing the energy dependence in the nucleus-nucleus potential (EDWSP model). In the EDWSP model calculations, a wide range of diffuseness parameter ranging from a = 0.85 fm to a = 0.97 fm, which is much larger than a value (a = 0.65 fm) extracted from the elastic scattering data, is needed to reproduce sub-barrier fusion data. However, such diffuseness anomaly, which might be an artifact of some dynamical effects, has been resolved by trajectory fluctuation dissipation (TFD) model wherein the resulting nucleus-nucleus potential possesses normal diffuseness parameter.
Gautam, Manjeet Singh, E-mail: gautammanjeet@gmail.com
2015-01-15
In the present work, the fusion of symmetric and asymmetric projectile–target combinations are deeply analyzed within the framework of energy dependent Woods–Saxon potential model (EDWSP model) in conjunction with one dimensional Wong formula and the coupled channel code CCFULL. The neutron transfer channels and the inelastic surface excitations of collision partners are dominating mode of couplings and the coupling of relative motion of colliding nuclei to such relevant internal degrees of freedom produces a significant fusion enhancement at sub-barrier energies. It is quite interesting that the effects of dominant intrinsic degrees of freedom such as multi-phonon vibrational states, neutron transfer channels and proton transfer channels can be simulated by introducing the energy dependence in the nucleus–nucleus potential (EDWSP model). In the EDWSP model calculations, a wide range of diffuseness parameter ranging from a=0.85 fm to a=0.97 fm, which is much larger than a value (a=0.65 fm) extracted from the elastic scattering data, is needed to reproduce sub-barrier fusion data. However, such diffuseness anomaly, which might be an artifact of some dynamical effects, has been resolved by trajectory fluctuation dissipation (TFD) model wherein the resulting nucleus–nucleus potential possesses normal diffuseness parameter.
Energy Dependent Time Delays of kHz Oscillations due to Thermal Comptonization
Kumar, Nagendra
2014-01-01
We study the energy dependent photon variability from a thermal Comptonizing plasma that is oscillating at kHz frequencies. In particular, we solve the linearised time dependent Kompaneets equation and consider the oscillatory perturbation to be either in the soft photon source or in the heating rate of the plasma. For each case, we self consistently consider the energy balance of the plasma and the soft photon source. The model incorporates the possibility of a fraction of the Comptonized photons impinging back into the soft photon source. We find that when the oscillation is due to the soft photon source, the variation of the fractional root mean sqaure (r.m.s) is nearly constant with energy and the time-lags are hard. However, for the case when the oscillation is due to variation in the heating rate of the corona, and when a significant fraction of the photons impinge back into the soft photon source, the r.m.s increases with energy and the time lags are soft. As an example, we compare the results with the...
Energy dependence of the freeze out eccentricity from the azimuthal dependence of HBT at STAR
,
2011-01-01
Non-central heavy ion collisions create an out-of-plane-extended participant zone that expands toward a more round state as the system evolves. The recent RHIC Beam Energy Scan at sqrt{s_{NN}} of 7.7, 11.5, and 39 GeV provide an opportunity to explore the energy dependence of the freeze out eccentricity. The new low energy data from STAR complements high statistics data sets at sqrt{s_{NN}} of 62.4 and 200 GeV. Hanbury-Brown-Twiss (HBT) interferometry allows to determine the size of pion emitting source regions. The dependence of the HBT radius parameters on azimuthal angle relative to the reaction plane have been extracted. These dependencies can be related to the freeze out eccentricity. The new results from STAR are consistent with a monotonically decreasing freeze out eccentricity and constrain any minimum, suggested by previously available data, to lie in the range between 11.5 and 39 GeV. Of several models UrQMD appears to best predict the STAR and AGS data.
Socratous, Josephine; Watanabe, Shun; Banger, Kulbinder K.; Warwick, Christopher N.; Branquinho, Rita; Barquinha, Pedro; Martins, Rodrigo; Fortunato, Elvira; Sirringhaus, Henning
2017-01-01
Despite the success of exploiting the properties of amorphous oxide semiconductors for device applications, the charge transport in these materials is still not clearly understood. The observation of a definite Hall voltage suggests that electron transport in the conduction band is free-electron-like. However, the temperature dependence of the Hall and field-effect mobilities cannot be explained using a simple bandlike model. Here, we perform gated Hall effect measurements in field-effect transistors, which allow us to make two independent estimates of the charge carrier concentration and determine the Hall factor providing information on the energy dependence of the relaxation time. We demonstrate that the Hall factor in a range of sputtered and solution-processed quaternary amorphous oxides, such as a-InGaZnO, is close to two, while in ternary oxides, such as InZnO, it is near unity. This suggests that quaternary elements like Ga act as strong ionized impurity scattering centers in these materials.
Kellerman, Adam; Makarevich, Roman; Spanswick, Emma; Donovan, Eric; Shprits, Yuri
2016-07-01
Energetic electrons in the 10's of keV range precipitate to the upper D- and lower E-region ionosphere, and are responsible for enhanced ionization. The same particles are important in the inner magnetosphere, as they provide a source of energy for waves, and thus relate to relativistic electron enhancements in Earth's radiation belts.In situ observations of plasma populations and waves are usually limited to a single point, which complicates temporal and spatial analysis. Also, the lifespan of satellite missions is often limited to several years which does not allow one to infer long-term climatology of particle precipitation, important for affecting ionospheric conditions at high latitudes. Multi-point remote sensing of the ionospheric plasma conditions can provide a global view of both ionospheric and magnetospheric conditions, and the coupling between magnetospheric and ionospheric phenomena can be examined on time-scales that allow comprehensive statistical analysis. In this study we utilize multi-point riometer measurements in conjunction with in situ satellite data, and physics-based modeling to investigate the spatio-temporal and energy-dependent response of riometer absorption. Quantifying this relationship may be a key to future advancements in our understanding of the complex D-region ionosphere, and may lead to enhanced specification of auroral precipitation both during individual events and over climatological time-scales.
Optical-based spectral modeling of infrared focal plane arrays
Mouzali, Salima; Lefebvre, Sidonie; Rommeluère, Sylvain; Ferrec, Yann; Primot, Jérôme
2016-07-01
We adopt an optical approach in order to model and predict the spectral signature of an infrared focal plane array. The modeling is based on a multilayer description of the structure and considers a one-dimensional propagation. It provides a better understanding of the physical phenomena occurring within the pixels, which is useful to perform radiometric measurements, as well as to reliably predict the spectral sensitivity of the detector. An exhaustive model is presented, covering the total spectral range of the pixel response. A heuristic model is also described, depicting a complementary approach that separates the different optical phenomena inside the pixel structure. Promising results are presented, validating the models through comparison with experimental results. Finally, advantages and limitations of this approach are discussed.
Electron Correlation Models for Optical Activity
Höhn, E. G.; O. E. Weigang, Jr.
1968-01-01
A two-system no-overlap model for rotatory strength is developed for electric-dipole forbidden as well as allowed transitions. General equations which allow for full utilization of symmetry in the chromophore and in the environment are obtained. The electron correlation terms are developed in full...
On recoil energy dependent void swelling in pure copper: Theoretical treatment
Golubov, S.I. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Singh, B.N.; Trinkaus, H. [Institute fuer Festkoerperforschung, Forschungszentrum Juelich (Germany)
2000-06-15
Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known either experimentally or theoretically about the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoil energy on the damage accumulation behaviour in pure copper and the results have been reported in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which the effect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 MeV electron) has been treated in terms of the standard rate theory (SRT) model whereas the evolution of the defect microstructure under cascade damage conditions (e.g. 3.0 MeV protons and fission neutrons) has been calculated within the framework of the production bias model (PBM). Theoretical results, in agreement with experimental results, show that the damage accumulation behaviour is very sensitive to recoil energy and under cascade damage conditions can be treated only within the framework of the PBM. The intracascade clustering of self-interstitial atoms (SIAs) and the properties of SIA clusters such as one-dimensional diffusional transport and thermal stability are found to be the main reasons for the recoil energy dependent vacancy supersaturation. The vacancy supersaturation is the main driving force for the void nucleation and void swelling. In the case of Frenkel pair production, the experimental results are found to be consistent with the SRT model with a dislocation bias value of 2 %. (au)
Modeling, fabrication and high power optical characterization of plasmonic waveguides
Lavrinenko, Andrei; Lysenko, Oleg
2015-01-01
This paper describes modeling, fabrication and high power optical characterization of thin gold films embedded in silicon dioxide. The propagation vector of surface plasmon polaritons has been calculated by the effective index method for the wavelength range of 750-1700 nm and film thickness of 1...
Classification of scalar and dyadic nonlocal optical response models
Wubs, Martijn
2015-01-01
Nonlocal optical response is one of the emerging effects on the nanoscale for particles made of metals or doped semiconductors. Here we classify and compare both scalar and tensorial nonlocal response models. In the latter case the nonlocality can stem from either the longitudinal response...
Fast Cherenkov model of optical photons generation and transportation
The ATLAS collaboration
2017-01-01
This note describes the technical details of Fast Cherenkov model of optical photons generation and transportation: in particular, the mechanism of Cherenkov photons transportation through the straight bar geometry. As an example of usage, the implemetation of the method inside Quartic detector simulation in GEANT4 will be presented and compared to the nominal results.
Modelling exciton–phonon interactions in optically driven quantum dots
Nazir, Ahsan; McCutcheon, Dara
2016-01-01
We provide a self-contained review of master equation approaches to modelling phonon effects in optically driven self-assembled quantum dots. Coupling of the (quasi) two-level excitonic system to phonons leads to dissipation and dephasing, the rates of which depend on the excitation conditions...
Three dimensional rigorous model for optical scattering problems
Wei, X.
2006-01-01
We present a three-dimensional model based on the finite element method for solving the time-harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals, and to many configurations such as an isolated scatterer in a multilayer, bi-gratings and crystals. We shal
Quantum Electrostatic Model for Optical Properties of Nanoscale Gold Films
Qian Haoliang
2015-11-01
Full Text Available The optical properties of thin gold films with thickness varying from 2.5 nm to 30 nm are investigated. Due to the quantum size effect, the optical constants of the thin gold film deviate from the Drude model for bulk material as film thickness decreases, especially around 2.5 nm, where the electron energy level becomes discrete. A theory based on the self-consistent solution of the Schrödinger equation and the Poisson equation is proposed and its predictions agree well with experimental results.
Modeling, fabrication and high power optical characterization of plasmonic waveguides
Lavrinenko, Andrei; Lysenko, Oleg
2015-01-01
This paper describes modeling, fabrication and high power optical characterization of thin gold films embedded in silicon dioxide. The propagation vector of surface plasmon polaritons has been calculated by the effective index method for the wavelength range of 750-1700 nm and film thickness of 15......, 30 and 45 nm. The fabrication process of such plasmonic waveguides with width in the range of 1-100 μm and their quality inspection are described. The results of optical characterization of plasmonic waveguides using a high power laser with the peak power wavelength 1064 nm show significant deviation...
Trapped ions in optical lattices for probing oscillator chain models
Pruttivarasin, Thaned; Talukdar, Ishan; Kreuter, Axel; Haeffner, Hartmut
2011-01-01
We show that a chain of trapped ions embedded in microtraps generated by an optical lattice can be used to study oscillator models related to dry friction and energy transport. Numerical calculations with realistic experimental parameters demonstrate that both static and dynamic properties of the ion chain change significantly as the optical lattice power is varied. Finally, we lay out an experimental scheme to use the spin degree of freedom to probe the phase space structure and quantum critical behavior of the ion chain.
Energy dependence of pion inelastic scattering to the 1/sup +/ states in /sup 12/C
Oakley, D.S.; Peterson, R.J.; Rilett, D.J.; Morris, C.L.; Greene, S.J.; Boyer, B.; Johnson, K.; Fuentes, A.H.; McDonald, J.W.; Smithson, M.J.; and others
1988-12-01
The energy dependence of cross sections for inelastic pion scattering to the /Delta/ = /Delta/ = /Delta/ = 1 transition at 15.11 MeV in /sup 12/C is found to map very closely the /Delta/ = /Delta/ = /Delta/+1 /pi/-nucleon scattering cross sections at beam energies from 50 to 295 MeV. This free /pi/-nucleon energy dependence is due to the prominent /Delta/sub 3/2,3/2/ resonance, corresponding to the first excited nucleon state, which is mirrored in the /pi/-nucleus system with little alteration.
Computational Modeling of Ultrafast Pulse Propagation in Nonlinear Optical Materials
Goorjian, Peter M.; Agrawal, Govind P.; Kwak, Dochan (Technical Monitor)
1996-01-01
There is an emerging technology of photonic (or optoelectronic) integrated circuits (PICs or OEICs). In PICs, optical and electronic components are grown together on the same chip. rib build such devices and subsystems, one needs to model the entire chip. Accurate computer modeling of electromagnetic wave propagation in semiconductors is necessary for the successful development of PICs. More specifically, these computer codes would enable the modeling of such devices, including their subsystems, such as semiconductor lasers and semiconductor amplifiers in which there is femtosecond pulse propagation. Here, the computer simulations are made by solving the full vector, nonlinear, Maxwell's equations, coupled with the semiconductor Bloch equations, without any approximations. The carrier is retained in the description of the optical pulse, (i.e. the envelope approximation is not made in the Maxwell's equations), and the rotating wave approximation is not made in the Bloch equations. These coupled equations are solved to simulate the propagation of femtosecond optical pulses in semiconductor materials. The simulations describe the dynamics of the optical pulses, as well as the interband and intraband.
Minimal model for optical transmission through holey metal films
MartIn-Moreno, L [Departamento de Fisica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); GarcIa-Vidal, F J [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: lmm@unizar.es
2008-07-30
This paper presents a tutorial on the computation of both extraordinary optical transmission and surface electromagnetic modes in holey metal films. Our model consists of a square array of square holes in a perfect conductor. It is shown that considering just the fundamental waveguide mode inside the holes captures the main features of the optical transmission, which allows us to obtain quasi-analytical results. Extraordinary optical transmission is unambiguously linked to the presence of surface electromagnetic modes in the corrugated structure. The particular case of surface electromagnetic modes in a perfect conductor is analyzed, paying attention to different strategies for increasing their confinement to the surface. The use of the energy loss of a charged particle passing close to the surface as a spectroscopic tool for these surface modes is also discussed.
Comprehensive analytical model to characterize randomness in optical waveguides.
Zhou, Junhe; Gallion, Philippe
2016-04-01
In this paper, the coupled mode theory (CMT) is used to derive the corresponding stochastic differential equations (SDEs) for the modal amplitude evolution inside optical waveguides with random refractive index variations. Based on the SDEs, the ordinary differential equations (ODEs) are derived to analyze the statistics of the modal amplitudes, such as the optical power and power variations as well as the power correlation coefficients between the different modal powers. These ODEs can be solved analytically and therefore, it greatly simplifies the analysis. It is demonstrated that the ODEs for the power evolution of the modes are in excellent agreement with the Marcuse' coupled power model. The higher order statistics, such as the power variations and power correlation coefficients, which are not exactly analyzed in the Marcuse' model, are discussed afterwards. Monte-Carlo simulations are performed to demonstrate the validity of the analytical model.
Field weighting model for tracking-integrated optics
Wheelwright, Brian; Angel, Roger; Coughenour, Blake; Hammer, Kimberly; Geary, Andrew; Stalcup, Thomas
2014-09-01
The emergent field of tracking-integrated optics enables a potentially low cost concentrating photovoltaic (CPV) implementation, where single-axis module tracking is complemented by an additional degree of freedom within the module [1,2,3,4,5]. Gross module tracking can take on multiple configurations, the most common being rotation about a polar or horizontal North-South oriented axis. Polar-axis tracking achieves >95% sunlight collection compared to dual-axis tracking[6], leaving the tracking-integrated optics to compensate for +/-23.5° seasonal variations. The collection efficiency of N-S horizontal axis tracking is latitude-dependent, with ˜90% collection relative to dual-axis tracking at 32.2° latitude. Horizontal tracking at higher latitudes shifts an increasing burden to the tracking-integrated optics, which must operate between two incidence angle extremes: summer solstice sunrise/sunset to winter solstice noon. An important aspect of tracking-integrated lens design is choosing a suitable field weighting to appropriately account for annual DNI received at each angle of incidence. We present a field weighting model, generalized for polar or horizontal module tracking at any latitude, which shows excellent agreement with measured insolation data. This model is particularly helpful for the design of tracking-integrated optics for horizontally-tracked modules, where the correct field weighting is asymmetric and significantly biased away from the normal incidence.
Some Advances in the Circuit Modeling of Extraordinary Optical Transmission
F. Medina
2009-06-01
Full Text Available The phenomenon of extraordinary optical transmission (EOT through electrically small holes perforated on opaque metal screens has been a hot topic in the optics community for more than one decade. This experimentally observed frequency-selective enhanced transmission of electromagnetic power through holes, for which classical Bethe's theory predicts very poor transmission, later attracted the attention of engineers working on microwave engineering or applied electromagnetics. Extraordinary transmission was ﬁrst linked to the plasma-like behavior of metals at optical frequencies. However, the primary role played by the periodicity of the distribution of holes was soon made evident, in such a way that extraordinary transmission was disconnected from the particular behavior of metals at optical frequencies. Indeed, the same phenomenon has been observed in the microwave and millimeter wave regime, for instance. Nowadays, the most commonly accepted theory explains EOT in terms of the interaction of the impinging plane wave with the surface plasmon-polariton-Bloch waves (SPP-Bloch supported by the periodically perforated plate. The authors of this paper have recently proposed an alternative model whose details will be brieﬂy summarized here. A parametric study of the predictions of the model and some new potential extensions will be reported to provide additional insight.
Oliveira, Mercia Liane de; Galindo, Renata Sales; Hazin, Clovis Abrahao, E-mail: mercial@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN/NE-CNEN/PE), Recife, PE (Brazil); Maia, Ana Figueiredo [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Fisica; Nascimento, Natalia Cassia do Espirito Santo; Fragoso, Maria da Conceicao de Farias [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)
2010-04-15
Objective: this study was aimed at evaluating the influence of the energy dependence of thermoluminescent materials on the determination of entrance skin dose in patients submitted to conventional radiographic studies (general radiology, mammography and dental radiology). Materials and methods: three different thermoluminescent materials were utilized: LiF:Mg,Ti, LiF:Mg,Cu,P and CaSO{sub 4}:Dy. These materials were exposed to standardized sources of X and gamma radiation and clinical X-ray beams. Results: calibration and energy dependence curves were obtained. All the materials showed a linear response as a function of the air kerma. As far as energy dependence is concerned, the CaSO{sub 4}:Dy and LiF:Mg,Ti samples showed the greatest variation on thermoluminescent responses as a function of the effective radiation beam. Conclusion: the tested materials showed an appropriate performance for detecting X radiation on standard and clinical X-ray beams. Although CaSO{sub 4}:Dy and LiF:Mg,Ti samples present a significant energy dependence in the considered energy range, these materials can be utilized for measuring entrance skin doses, provided appropriate correction factors are applied (author)
Darboux Transformations for Energy-Dependent Potentials and the Klein-Gordon Equation
Schulze-Halberg, Axel, E-mail: axgeschu@iun.edu [Indiana University Northwest, Department of Mathematics and Actuarial Science (United States)
2013-06-15
We construct explicit Darboux transformations for a generalized Schroedinger-type equation with energy-dependent potential, a special case of which is the stationary Klein-Gordon equation. Our results complement and generalize former findings (Lin et al., Phys Lett A 362:212-214, 2007).
Measurement of the energy dependence of the total photon-proton cross section at HERA
Abramowicz, H.; Abt, I.; Adamczykm, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E. G.; Borras, K.; Boscherini, D.; Boutle, S. K.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Butterworth, J. M.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Huettmann, A.; Iacobucci, G.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H. -P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kamauddin, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaurg, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Koetz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Loizides, J. H.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Luniak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I. -A.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. C.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcatov, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Whyte, J.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.
2011-01-01
The energy dependence of the photon-proton total cross section, sigma(gamma p)(tot), was determined from e(+) p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the gamma p system in the range 194
Energy dependence of hadronic observables in central Pb+Pb reactions at the CERN SPS
Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncic, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Darmenov, N; Dimitrov, A; Dinkelaker, P; Eckardt, V; Farantatos, G; Flierl, D; Fodor, Z; Foka, P; Freund, P; Friese, V; Gál, J; Gazdzicki, M; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kliemant, M; Kniege, S; Kolesnikov, V I; Kollegger, T; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Markert, C; Mateev, M; Mayes, B W; Melkumov, G L; Meurer, C; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R; Richard, A; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Stefanek, C; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Yoo, I K; Zaranek, J; Zimányi, J
2005-01-01
In this contribution the energy dependence of various hadronic observables as measured by the NA49 experiment in the beam energy range between 20 and 158 AGeV is presented. These include m/sub t/ and rapidity distributions, particle ratio fluctuations, as well as HBT radii. The data are put in the context of results from the AGS and RHIC.
Time-domain model of quantum-dot semiconductor optical amplifiers for wideband optical signals.
Puris, D; Schmidt-Langhorst, C; Lüdge, K; Majer, N; Schöll, E; Petermann, K
2012-11-19
We present a novel theoretical time-domain model for a quantum dot semiconductor optical amplifier, that allows to simulate subpicosecond pulse propagation including power-based and phase-based effects. Static results including amplified spontaneous emission spectra, continuous wave amplification, and four-wave mixing experiments in addition to dynamic pump-probe simulations are presented for different injection currents. The model uses digital filters to describe the frequency dependent gain and microscopically calculated carrier-carrier scattering rates for the interband carrier dynamics. It can be used to calculate the propagation of multiple signals with different wavelengths or one wideband signal with high bitrate.
Multiple Fan-Beam Optical Tomography: Modelling Techniques
Pang Jon Fea
2009-10-01
Full Text Available This paper explains in detail the solution to the forward and inverse problem faced in this research. In the forward problem section, the projection geometry and the sensor modelling are discussed. The dimensions, distributions and arrangements of the optical fibre sensors are determined based on the real hardware constructed and these are explained in the projection geometry section. The general idea in sensor modelling is to simulate an artificial environment, but with similar system properties, to predict the actual sensor values for various flow models in the hardware system. The sensitivity maps produced from the solution of the forward problems are important in reconstructing the tomographic image.
Fiber optic displacement measurement model based on finite reflective surface
Li, Yuhe; Guan, Kaisen; Hu, Zhaohui
2016-10-01
We present a fiber optic displacement measurement model based on finite reflective plate. The theoretical model was derived, and simulation analysis of light intensity distribution, reflective plate width, and the distance between fiber probe and reflective plate were conducted in details. The three dimensional received light intensity distribution and the characteristic curve of light intensity were studied as functions of displacement of finite reflective plate. Experiments were carried out to verify the established model. The physical fundamentals and the effect of operating parameters on measuring system performance were revealed in the end.
Chiba, Satoshi; Niita, Koji; Fukahori, Tokio; Maruyama, Tomoyuki; Maruyama, Toshiki; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-05-01
Energy dependence of the ratio of the isovector and isoscalar strengths in the imaginary part of the nucleon optical model potential at the medium energy range was extracted from an analysis of proton and neutron induced total reaction cross sections on {sup 11}Li with a theoretical framework called quantum molecular dynamics (QMD). The isovector/isoscalar ratio was found to be about 0.8 at 100 MeV, and decreased almost linearly in log(E) to 0 at several hundred MeV. This result was consistent with an estimate at lower energy, and was also in good accord with the values used by Kozack and Madland for the analysis of nucleon + {sup 208}Pb reactions. (author)
Waldecker, S J
2016-01-01
The nonlocal dispersive optical model (NLDOM) nucleon potentials are used for the first time in the adiabatic analysis of a (d,p) reaction to generate distorted waves both in the entrance and exit channels. These potentials were designed and fitted by Mahzoon $et \\text{ } al.$ [Phys. Rev. Lett. 112, 162502 (2014)] to constrain relevant single-particle physics in a consistent way by imposing the fundamental properties, such as nonlocality, energy-dependence and dispersive relations, that follow from the complex nature of nuclei. However, the NLDOM prediction for the $^{40}$Ca(d,p)$^{41}$Ca cross sections at low energy, typical for some modern radioactive beam ISOL facilities, is about 70$\\%$ higher than the experimental data despite being reduced by the NLDOM spectroscopic factor of 0.73. This overestimation comes most likely either from insufficient absorption or due to constructive interference between ingoing and outgoing waves. This indicates strongly that additional physics arising from many-body effects ...
Optical model for light distribution during transscleral cyclophotocoagulation
Nemati, B.; Dunn, A.; Welch, A.J.; Rylander, H.G. III [Medical Optics Laboratory, Biomedical Engineering Program, ENS 610, University of Texas, Austin, Texas 78712 (United States)
1998-02-01
Transscleral cyclophotocoagulation (TSCPC) is currently performed clinically as an effective treatment for end-stage glaucoma. We develop a theoretical model for the analysis of optical attenuation phenomena during TSCPC as a basis for selection of an optimal wavelength. A multilayered Monte Carlo model was developed to calculate the fluence and the rate of heat generation in each tissue layer for the wavelengths of Nd:YAG, diode, ruby, krypton yellow, and argon lasers. Of the five wavelengths under study, our theoretical results suggest that the diode laser wavelength offers the best penetration through the conjunctiva, sclera, and ciliary muscle and highest absorption within the ciliary pigment epithelium. {copyright} 1998 Optical Society of America.
Structural, thermal, optical and gravitational modelling for LISA
Merkowitz, Stephen M [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Conkey, Shelly [Swales Aerospace, 5050 Powder Mill Rd, Beltsville, MD 20705 (United States); Haile, William B [Swales Aerospace, 5050 Powder Mill Rd, Beltsville, MD 20705 (United States); KellyIII, William R [Swales Aerospace, 5050 Powder Mill Rd, Beltsville, MD 20705 (United States); Peabody, Hume [Swales Aerospace, 5050 Powder Mill Rd, Beltsville, MD 20705 (United States); Dumont, Philip J [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States)
2004-03-07
The laser interferometer space antenna (LISA) mission uses laser interferometry to detect and observe gravitational waves from astrophysical sources. Modelling of LISA ultimately needs to forecast and interrelate the behaviour of the science input, structure, optics, control systems and many other factors that affect the performance of the flight hardware. These models include high precision STOP (structural-thermal-optical) analyses. In addition, self-gravity analyses of the spacecraft, based on the structural-thermal modelling results, are required for each analysis cycle to understand the gravitational interaction between the spacecraft components. The complete analysis cycle is called STOP-G. Several aspects of this analysis require unprecedented precision due to LISA's challenging design requirements. We present here a modelling approach designed to minimize analysis errors, particularly those that enter when mapping results from one modelling step to the next. Central to the approach is the use of a single model topology for all phases of the STOP-G analysis cycle. The feasibility of this approach was verified using a simplified model of the LISA spacecraft.
Optical Thin Film Modeling: Using FTG's FilmStar Software
Freese, Scott
2009-01-01
Every material has basic optical properties that define its interaction with light: The index of refraction (n) and extinction coefficient (k) vary for the material as a function of the wavelength of the incident light. Also significant are the phase velocity and polarization of the incident light These inherent properties allow for the accurate modeling of light s behavior upon contact with a surface: Reflectance, Transmittance, Absorptance.
Quantum-dot Semiconductor Optical Amplifiers in State Space Model
Hussein Taleb; Kambiz Abedi; Saeed Golmohammadi
2013-01-01
A state space model (SSM) is derived for quantum-dot semiconductor optical amplifiers (QD-SOAs).Rate equations of QD-SOA are formulated in the form of state update equations,where average occupation probabilities along QD-SOA cavity are considered as state variables of the system.Simulations show that SSM calculates QD-SOA's static and dynamic characteristics with high accuracy.
Probabilistic Modeling of Intracranial Pressure Effects on Optic Nerve Biomechanics
Ethier, C. R.; Feola, Andrew J.; Raykin, Julia; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.
2016-01-01
Altered intracranial pressure (ICP) is involved/implicated in several ocular conditions: papilledema, glaucoma and Visual Impairment and Intracranial Pressure (VIIP) syndrome. The biomechanical effects of altered ICP on optic nerve head (ONH) tissues in these conditions are uncertain but likely important. We have quantified ICP-induced deformations of ONH tissues, using finite element (FE) and probabilistic modeling (Latin Hypercube Simulations (LHS)) to consider a range of tissue properties and relevant pressures.
Modeling magneto-optical trapping of CaF molecules
Tarbutt, M. R.; Steimle, T. C.
2015-11-01
Magneto-optical trapping forces for molecules are far weaker than for alkali-metal atoms because the photon scattering rate is reduced when there are multiple ground states, and because of optical pumping into dark states. The force is further reduced when the upper state has a much smaller Zeeman splitting than the lower state. We use a rate model to estimate the strength of the trapping and damping forces in a magneto-optical trap (MOT) of CaF molecules, using either the A 2Π1 /2-X 2Σ+ transition or the B 2Σ+-X 2Σ+ transition. We identify a mechanism of magneto-optical trapping that arises when, in each beam of the MOT, two laser components with opposite polarizations and different detunings address the same transition. This mechanism produces a strong trapping force even when the upper state has little or no Zeeman splitting. It is the main mechanism responsible for the trapping force when the A 2Π1 /2-X 2Σ+ transition is used.
Modeling magneto-optical trapping of CaF molecules
Tarbutt, M R
2015-01-01
Magneto-optical trapping forces for molecules are far weaker than for alkali atoms because the photon scattering rate is reduced when there are multiple ground states, and because of optical pumping into dark states. The force is further reduced when the upper state has a much smaller Zeeman splitting than the lower state. We use a rate model to estimate the strength of the trapping and damping forces in a magneto-optical trap (MOT) of CaF molecules, using either the A$^{2}\\Pi_{1/2}$ - X$^{2}\\Sigma^{+}$ transition or the B$^{2}\\Sigma^{+}$ - X$^{2}\\Sigma^{+}$ transition. We identify a new mechanism of magneto-optical trapping that arises when, in each beam of the MOT, two laser components with opposite polarizations and different detunings address the same transition. This mechanism produces a strong trapping force even when the upper state has little or no Zeeman splitting. It is the main mechanism responsible for the trapping force when the A$^{2}\\Pi_{1/2}$ - X$^{2}\\Sigma^{+}$ transition is used.
Modeling of optical losses in perovskite solar cells
Taghavi, M. Javad; Houshmand, Mohammad; Zandi, M. Hossein; Gorji, Nima E.
2016-09-01
The optical losses within the structure of hybrid perovskite solar cells are investigated using only the optical properties of each layer e.g. refractive index and extinction coefficient. This model allows calculating the transmission/reflection rates at the interfaces and absorption loss within any layer. Then, the short circuit current density and loss percentage are calculated versus the perovskite and TiO2 thicknesses from 50 nm to 150 nm. To make our calculations closer to reality, we extracted the optical properties of each device component from the literature reports on glass/TCO/TiO2/perovskite/metal. The simulations were fitted with the experimental results of some relevant references. Our simulations show that ITO transmits the light better than SnO2 as the TCO front electrode, and the light reflection at both sides of the perovskite layer, e.g. at TiO2/perovskite and perovskite/Spiro-OMeTAD, is lower than 25%. The light interference and multiple reflections have been accounted in our calculations and finally we showed that a thicker TiO2 and perovskite cause more optical loss in current density due to stronger absorption.
Alliss, R.
2014-09-01
Optical turbulence (OT) acts to distort light in the atmosphere, degrading imagery from astronomical telescopes and reducing the data quality of optical imaging and communication links. Some of the degradation due to turbulence can be corrected by adaptive optics. However, the severity of optical turbulence, and thus the amount of correction required, is largely dependent upon the turbulence at the location of interest. Therefore, it is vital to understand the climatology of optical turbulence at such locations. In many cases, it is impractical and expensive to setup instrumentation to characterize the climatology of OT, so numerical simulations become a less expensive and convenient alternative. The strength of OT is characterized by the refractive index structure function Cn2, which in turn is used to calculate atmospheric seeing parameters. While attempts have been made to characterize Cn2 using empirical models, Cn2 can be calculated more directly from Numerical Weather Prediction (NWP) simulations using pressure, temperature, thermal stability, vertical wind shear, turbulent Prandtl number, and turbulence kinetic energy (TKE). In this work we use the Weather Research and Forecast (WRF) NWP model to generate Cn2 climatologies in the planetary boundary layer and free atmosphere, allowing for both point-to-point and ground-to-space seeing estimates of the Fried Coherence length (ro) and other seeing parameters. Simulations are performed using a multi-node linux cluster using the Intel chip architecture. The WRF model is configured to run at 1km horizontal resolution and centered on the Mauna Loa Observatory (MLO) of the Big Island. The vertical resolution varies from 25 meters in the boundary layer to 500 meters in the stratosphere. The model top is 20 km. The Mellor-Yamada-Janjic (MYJ) TKE scheme has been modified to diagnose the turbulent Prandtl number as a function of the Richardson number, following observations by Kondo and others. This modification
Modeling method and preliminary model of Asteroid Toutatis from Chang'E-2 optical images
Li, Xiang-Yu; Qiao, Dong
2014-06-01
Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang'E-2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the mission. In this paper, the modeling method and preliminary model of Asteroid Toutatis are discussed. First, the optical images obtained by Chang'E-2 are analyzed. Terrain and silhouette features in images are described. Then, the modeling method based on previous radar model and preliminary information from optical images is proposed. A preliminary polyhedron model of Asteroid Toutatis is established. Finally, the spherical harmonic coefficients of Asteroid Toutatis based on the polyhedron model are obtained. Some parameters of model are analyzed and compared. Although the model proposed in this paper is only a preliminary model, this work offers a valuable reference for future high-resolution models.
Model of optical response of marine aerosols to Forbush decreases
T. Bondo
2010-03-01
Full Text Available In order to elucidate the effect of galactic cosmic rays on cloud formation, we investigate the optical response of marine aerosols to Forbush decreases – abrupt decreases in galactic cosmic rays – by means of modeling. We vary the nucleation rate of new aerosols, in a sectional coagulation and condensation model, according to changes in ionization by the Forbush decrease. From the resulting size distribution we then calculate the aerosol optical thickness and Angstrom exponent, for the wavelength pairs 350, 450 nm and 550, 900 nm. In the cases where the output parameters from the model seem to compare best with atmospheric observations we observe, for the shorter wavelength pair, a change in Angstrom exponent, following the Forbush Decrease, of −6 to +3%. In some cases we also observe a delay in the change of Angstrom exponent, compared to the maximum of the Forbush decrease, which is caused by different sensitivities of the probing wavelengths to changes in aerosol number concentration and size. For the long wavelengths these changes are generally smaller. The types and magnitude of change is investigated for a suite of nucleation rates, condensable gas production rates, and aerosol loss rates. Furthermore we compare the model output with observations of 5 of the largest Forbush decreases after year 2000. For the 350, 450 nm pair we use AERONET data and find a comparable change in signal while the Angstrom Exponent is lower in the model than in the data, due to AERONET being mainly sampled over land. For 550, 900 nm we compare with both AERONET and MODIS and find little to no response in both model and observations. In summary our study shows that the optical properties of aerosols show a distinct response to Forbush Decreases, assuming that the nucleation of fresh aerosols is driven by ions. Shorter wavelengths seem more favorable for observing these effects and great care should be taken when analyzing observations, in order to avoid
Optical modeling of graphene contacted CdTe solar cells
Aldosari, Marouf; Sohrabpoor, Hamed; Gorji, Nima E.
2016-04-01
For the first time, an optical model is applied on CdS/CdTe thin film solar cells with graphene front or back contact. Graphene is highly conductive and is as thin as a single atom which reduces the light reflection and absorption, and thus enhances the light transmission to CdTe layer for a wide range of wavelengths including IR. Graphene as front electrode of CdTe devices led to loss in short circuit current density of 10% ΔJsc ≤ 15% compared to the conventional electrodes of TCO and ITO at CdS thickness of dCdS = 100 nm. In addition, all the multilayer graphene electrodes with 2, 4, and 7 graphene layers led to Jsc ≤ 20 mA/cm2. Therefore, we conclude that a single monolayer graphene with hexagonal carbon network reduces optical losses and enhances the carrier collection measured as Jsc. In another structure design, we applied the optical model to graphene back contacted CdS/CdTe device. This scheme allows double side irradiation of the cell which is expected to enhance the Jsc. We obtained 1 ∼ 6 , 23, and 38 mA/cm2 for back, front and bifacial illumination of graphene contacted CdTe cell with CdS = 100 nm. The bifacial irradiated cell, to be efficient, requires an ultrathin CdTe film with dCdTe ≤ 1 μm. In this case, the junction electric field extends to the back region and collects out the generated carriers efficiently. This was modelled by absorptivity rather than transmission rate and optical losses. Since the literature suggest that ZnO can increase the graphene conductivity and enhance the Jsc, we performed our simulations for a graphene/ZnO electrode (ZnO = 100 nm) instead of a single graphene layer.
An improved transfer-matrix model for optical superlenses.
Moore, Ciaran P; Blaikie, Richard J; Arnold, Matthew D
2009-08-01
The use of transfer-matrix analyses for characterizing planar optical superlensing systems is studied here, and the simple model of the planar superlens as an isolated imaging element is shown to be defective in certain situations. These defects arise due to neglected interactions between the superlens and the spatially varying shadow masks that are normally used as scattering objects for imaging, and which are held in near-field proximity to the superlenses. An extended model is proposed that improves the accuracy of the transfer-matrix analysis, without adding significant complexity, by approximating the reflections from the shadow mask by those from a uniform metal layer. Results obtained using both forms of the transfer matrix model are compared to finite element models and two example superlenses, one with a silver monolayer and the other with three silver sublayers, are characterized. The modified transfer matrix model gives much better agreement in both cases.
Adiabatic Floquet model for the optical response in femtosecond filaments
Hofmann, Michael
2016-01-01
The standard model of femtosecond filamentation is based on phenomenological assumptions which suggest that the ionization-induced carriers can be treated as free according to the Drude model, while the nonlinear response of the bound carriers follows the all-optical Kerr effect. Here, we demonstrate that the additional plasma generated at a multiphoton resonance dominates the saturation of the nonlinear refractive index. Since resonances are not captured by the standard model, we propose a modification of the latter in which ionization enhancements can be accounted for by an ionization rate obtained from non-Hermitian Floquet theory. In the adiabatic regime of long pulse envelopes, this augmented standard model is in excellent agreement with direct quantum mechanical simulations. Since our proposal maintains the structure of the standard model, it can be easily incorporated into existing codes of filament simulation.
Event-based Corpuscular Model for Quantum Optics Experiments
Michielsen, K; De Raedt, H
2010-01-01
A corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one is presented. The event-based corpuscular model is shown to give a unified description of multiple-beam fringes of a plane parallel plate, single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum erasers, two-beam interference, double-slit, and Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments.
Computational Model Of Fiber Optic, Arc Fusion Splicing; Experimental Comparison
Ruffin, Paul; Frost, Walter; Long, Wayne
1989-02-01
Acknowledgement: The assistance and support of the MICOM Army Missile Command is gratefully appreciated. An analytical tool to investigate the arc fusion splicing of optical fibers is developed. The physical model incorporates heat transfer and thermal, visco elastic strain. The heat transfer equations governing radiation, conduction and convection during arc heating are formulated. The radiation heat flux impinging on the fiber optics is modeled based on reported experimental analysis of a generic type arc discharge. The fusion process considers deformation of the fiber due to thermal, viscous and elastic strain. A Maxwell stress-strain relationship is assumed. The model assumes an initial gap at the beginning of the arc which is closed by a press-stroke during the heating cycle. All physical properties of the fused silica glass fibers are considered as functions of temperature based on available experimental data. A computer algorithm has been developed to solve the system of governing equations and parametric studies carried out. An experiment using a FSM-20 arc fusion splicer manufactured by Fujikura Ltd. was carried out to provide experimental verification of the analytical model. In the experiment a continuous fiber was positioned in the arc and cyclic heating and cooling was carried out. One end of the fiber was clamped and the other was free to move. The fiber was heated for 6 seconds and cooled for 3 minutes for several cycles. At the end of each cooling process, photographs of the deformation of the fiber were taken. The results showed that the fiber necked down on the free end and buldged up on the fixed end. With repeated heating and cooling cycles, the optical fiber eventually necked down to the point that it melted in two. The analytical model was run for the conditions of the experiment. Comparisons of the predicted deformation of the optical fiber with those measured is given. The analytical model displays all of the physical phenomenon of fiber
Non-rotational aspherical models of the human optical system
Giovanzana, S.; Kasprzak, H. T.; Pałucki, B.; Ţălu, Ş.
2013-12-01
The aim of this work was to define three-dimensional (3D) non-rotational aspherical parametric models for the human cornea and lens using computational geometry and CAD representations. The hyperbolic cosine based function is used for the cornea and a parametric model is used for lens modeling. Data analysis and visualization of 3D non-rotational models were made using the Rhinoceros CAD software and MATLAB software was used for numeric computation. We combined, implemented, and evaluated these models with a 3D ray-tracing in order to fully analyze the human eye model. It was found that 3D non-rotational aspherical models for the human eye could be more accurately modeled and rendered for analysis with finite element method. The objective of this study is to present and analyze mathematical models of the cornea and lens and to highlight the potential of optical applications of the eye models containing astigmatic surfaces, which are more close to the real eye than spherosymmetric eye models.
Multiple Scattering Model for Optical Coherence Tomography with Rytov Approximation
Li, Muxingzi
2017-04-24
Optical Coherence Tomography (OCT) is a coherence-gated, micrometer-resolution imaging technique that focuses a broadband near-infrared laser beam to penetrate into optical scattering media, e.g. biological tissues. The OCT resolution is split into two parts, with the axial resolution defined by half the coherence length, and the depth-dependent lateral resolution determined by the beam geometry, which is well described by a Gaussian beam model. The depth dependence of lateral resolution directly results in the defocusing effect outside the confocal region and restricts current OCT probes to small numerical aperture (NA) at the expense of lateral resolution near the focus. Another limitation on OCT development is the presence of a mixture of speckles due to multiple scatterers within the coherence length, and other random noise. Motivated by the above two challenges, a multiple scattering model based on Rytov approximation and Gaussian beam optics is proposed for the OCT setup. Some previous papers have adopted the first Born approximation with the assumption of small perturbation of the incident field in inhomogeneous media. The Rytov method of the same order with smooth phase perturbation assumption benefits from a wider spatial range of validity. A deconvolution method for solving the inverse problem associated with the first Rytov approximation is developed, significantly reducing the defocusing effect through depth and therefore extending the feasible range of NA.
Optical modeling of volcanic ash particles using ellipsoids
Merikallio, Sini; Muñoz, Olga; Sundström, Anu-Maija; Virtanen, Timo H.; Horttanainen, Matti; de Leeuw, Gerrit; Nousiainen, Timo
2015-05-01
The single-scattering properties of volcanic ash particles are modeled here by using ellipsoidal shapes. Ellipsoids are expected to improve the accuracy of the retrieval of aerosol properties using remote sensing techniques, which are currently often based on oversimplified assumptions of spherical ash particles. Measurements of the single-scattering optical properties of ash particles from several volcanoes across the globe, including previously unpublished measurements from the Eyjafjallajökull and Puyehue volcanoes, are used to assess the performance of the ellipsoidal particle models. These comparisons between the measurements and the ellipsoidal particle model include consideration of the whole scattering matrix, as well as sensitivity studies on the point of view of the Advanced Along Track Scanning Radiometer (AATSR) instrument. AATSR, which flew on the ENVISAT satellite, offers two viewing directions but no information on polarization, so usually only the phase function is relevant for interpreting its measurements. As expected, ensembles of ellipsoids are able to reproduce the observed scattering matrix more faithfully than spheres. Performance of ellipsoid ensembles depends on the distribution of particle shapes, which we tried to optimize. No single specific shape distribution could be found that would perform superiorly in all situations, but all of the best-fit ellipsoidal distributions, as well as the additionally tested equiprobable distribution, improved greatly over the performance of spheres. We conclude that an equiprobable shape distribution of ellipsoidal model particles is a relatively good, yet enticingly simple, approach for modeling volcanic ash single-scattering optical properties.
Adaptive optics sky coverage modeling for extremely large telescopes.
Clare, Richard M; Ellerbroek, Brent L; Herriot, Glen; Véran, Jean-Pierre
2006-12-10
A Monte Carlo sky coverage model for laser guide star adaptive optics systems was proposed by Clare and Ellerbroek [J. Opt. Soc. Am. A 23, 418 (2006)]. We refine the model to include (i) natural guide star (NGS) statistics using published star count models, (ii) noise on the NGS measurements, (iii) the effect of telescope wind shake, (iv) a model for how the Strehl and hence NGS wavefront sensor measurement noise varies across the field, (v) the focus error due to imperfectly tracking the range to the sodium layer, (vi) the mechanical bandwidths of the tip-tilt (TT) stage and deformable mirror actuators, and (vii) temporal filtering of the NGS measurements to balance errors due to noise and servo lag. From this model, we are able to generate a TT error budget for the Thirty Meter Telescope facility narrow-field infrared adaptive optics system (NFIRAOS) and perform several design trade studies. With the current NFIRAOS design, the median TT error at the galactic pole with median seeing is calculated to be 65 nm or 1.8 mas rms.
Wavefront Sensing for WFIRST with a Linear Optical Model
Jurling, Alden S.; Content, David A.
2012-01-01
In this paper we develop methods to use a linear optical model to capture the field dependence of wavefront aberrations in a nonlinear optimization-based phase retrieval algorithm for image-based wavefront sensing. The linear optical model is generated from a ray trace model of the system and allows the system state to be described in terms of mechanical alignment parameters rather than wavefront coefficients. This approach allows joint optimization over images taken at different field points and does not require separate convergence of phase retrieval at individual field points. Because the algorithm exploits field diversity, multiple defocused images per field point are not required for robustness. Furthermore, because it is possible to simultaneously fit images of many stars over the field, it is not necessary to use a fixed defocus to achieve adequate signal-to-noise ratio despite having images with high dynamic range. This allows high performance wavefront sensing using in-focus science data. We applied this technique in a simulation model based on the Wide Field Infrared Survey Telescope (WFIRST) Intermediate Design Reference Mission (IDRM) imager using a linear optical model with 25 field points. We demonstrate sub-thousandth-wave wavefront sensing accuracy in the presence of noise and moderate undersampling for both monochromatic and polychromatic images using 25 high-SNR target stars. Using these high-quality wavefront sensing results, we are able to generate upsampled point-spread functions (PSFs) and use them to determine PSF ellipticity to high accuracy in order to reduce the systematic impact of aberrations on the accuracy of galactic ellipticity determination for weak-lensing science.
Model of optical response of marine aerosols to Forbush decreases
T. Bondo
2009-10-01
Full Text Available In order to elucidate the effect of galactic cosmic rays on cloud formation, we investigate the optical response of marine aerosols to Forbush decreases – abrupt decreases in galactic cosmic rays – by means of modeling. We vary the nucleation rate of new aerosols, in a sectional coagulation and condensation model, according to changes in ionization by the Forbush decrease. From the resulting size distribution we then calculate the aerosol optical thickness and Angstrom exponent, for the wavelength pairs 350, 450 nm and 550, 900 nm. For the shorter wavelength pair we observe a change in Angstrom exponent, following the Forbush Decrease, of −6 to +3% in the cases with atmospherically realistic output parameters. For some parameters we also observe a delay in the change of Angstrom exponent, compared to the maximum of the Forbush decrease, which is caused by different sensitivities of the probing wavelengths to changes in aerosol number concentration and size. For the long wavelengths these changes are generally smaller. The types and magnitude of change is investigated for a suite of nucleation rates, condensable gas production rates, and aerosol loss rates. Furthermore we compare the model output with observations of 5 of the largest Forbush decreases after year 2000. For the 350, 450 nm pair we use AERONET data and find a comparable change in signal while the Angstrom Exponent is lower in the model than in the data, due to AERONET being mainly sampled over land. For 550, 900 nm we compare with both AERONET and MODIS and find little to no response in both model and observations. In summary our study shows that the optical properties of aerosols show a distinct response to Forbush Decreases, assuming that the nucleation of fresh aerosols is driven by ions. Shorter wavelengths seem more favorable for observing these effects and great care should be taken when analyzing observations, in order to avoid the signal being drowned out by noise.
Wavefront sensing for WFIRST with a linear optical model
Jurling, Alden S.; Content, David A.
2012-09-01
In this paper we develop methods to use a linear optical model to capture the field dependence of wavefront aberrations in a nonlinear optimization-based phase retrieval algorithm for image-based wavefront sensing. The linear optical model is generated from a ray trace model of the system and allows the system state to be described in terms of mechanical alignment parameters rather than wavefront coefficients. This approach allows joint optimization over images taken at different field points and does not require separate convergence of phase retrieval at individual field points. Because the algorithm exploits field diversity, multiple defocused images per field point are not required for robustness. Furthermore, because it is possible to simultaneously fit images of many stars over the field, it is not necessary to use a fixed defocus to achieve adequate signal-to-noise ratio despite having images with high dynamic range. This allows high performance wavefront sensing using in-focus science data. We applied this technique in a simulation model based on the Wide Field Infrared Survey Telescope (WFIRST) Intermediate Design Reference Mission (IDRM) imager using a linear optical model with 25 field points. We demonstrate sub-thousandth-wave wavefront sensing accuracy in the presence of noise and moderate undersampling for both monochromatic and polychromatic images using 25 high-SNR target stars. Using these high-quality wavefront sensing results, we are able to generate upsampled point-spread functions (PSFs) and use them to determine PSF ellipticity to high accuracy in order to reduce the systematic impact of aberrations on the accuracy of galactic ellipticity determination for weak-lensing science.
Numerical modelling of multimode fibre-optic communication lines
Sidelnikov, O S; Fedoruk, M P [Novosibirsk State University, Novosibirsk (Russian Federation); Sygletos, S; Ferreira, F [Aston University, England, Birmingham, B4 7ET (United Kingdom)
2016-01-31
The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong coupling regime provides a lower EVM level than the weak coupling one. (fibre-optic communication lines)
System for calibrating the energy-dependent response of an elliptical Bragg-crystal spectrometer.
Marrs, R E; Brown, G V; Emig, J A; Heeter, R F
2014-11-01
A multipurpose spectrometer (MSPEC) with elliptical crystals is in routine use to obtain x-ray spectra from laser produced plasmas in the energy range 1.0-9.0 keV. Knowledge of the energy-dependent response of the spectrometer is required for an accurate comparison of the intensities of x-ray lines of different energy. The energy-dependent response of the MSPEC has now been derived from the spectrometer geometry and calibration information on the response of its components, including two different types of detectors. Measurements of the spectrometer response with a laboratory x-ray source are used to test the calculated response and provide information on crystal reflectivity and uniformity.
Measurements of the spectrum and energy dependence of X-ray transition radiation
Cherry, M. L.
1978-01-01
The results of experiments designed to test the theory of X-ray transition radiation and to verify the predicted dependence of the characteristic features of the radiation on the radiator dimensions are presented. The X-ray frequency spectrum produced by 5- to 9-GeV electrons over the range 4 to 30 keV was measured with a calibrated single-crystal Bragg spectrometer, and at frequencies up to 100 keV with an NaI scintillator. The interference pattern in the spectrum and the hardening of the radiation with increasing foil thickness are clearly observed. The energy dependence of the total transition-radiation intensity was studied using a radiator with large dimensions designed to yield energy-dependent signals at very high particle energies, up to E/mc-squared approximately equal to 100,000. The results are in good agreement with the theoretical predictions.
Waldecker, S. J.; Timofeyuk, N. K.
2016-09-01
The nonlocal dispersive optical model (NLDOM) nucleon potentials are used for the first time in the adiabatic analysis of a (d ,p ) reaction to generate distorted waves both in the entrance and exit channels. These potentials were designed and fitted by Mahzoon et al. [Phys. Rev. Lett. 112, 162503 (2014), 10.1103/PhysRevLett.112.162503] to constrain relevant single-particle physics in a consistent way by imposing the fundamental properties, such as nonlocality, energy-dependence and dispersive relations, that follow from the complex nature of nuclei. However, the NLDOM prediction for the 40Ca(d ,p )41Ca cross sections at low energy, typical for some modern radioactive beam ISOL (isotope separation online) facilities, is about 70% higher than the experimental data despite being reduced by the NLDOM spectroscopic factor of 0.73. This overestimation comes most likely either from insufficient absorption or due to constructive interference between ingoing and outgoing waves. This indicates strongly that additional physics arising from many-body effects is missing in the widely used current versions of (d ,p ) reaction theories.
Calculation of the Energy Dependence of Dosimeter Response to Ionizing Photons
Miller, Arne; McLaughlin, W. L.
1982-01-01
Using a program in BASIC applied to a desk-top calculator, simplified calculations provide approximate energy dependence correction factors of dosimeter readings of absorbed dose according to Bragg-Gray cavity theories. Burlin's general cavity theory is applied in the present calculations, and ce...... as given here are available for certain dosimeter probe materials and combinations used with intermediate energy photon spectra (0.01–100 MeV)....
Beam energy dependence of two-proton correlations at the AGS
Panitkin, S Y; Alexander, J; Anderson, M; Best, D; Brady, F P; Case, T; Caskey, W; Cebra, D; Chance, J; Chung, J; Cole, B; Crowe, K M; Das, A; Draper, J E; Gilkes, M L; Gushue, S; Heffner, M; Hirsch, A; Hjort, E; Huo, L; Justice, M; Kaplan, M; Keane, D; Kintner, J C; Klay, J L; Krofcheck, D; Lacey, R A; Lisa, M A; Liu, H; Liu, Y; McGrath, R; Milosevich, Z; Odyniec, Grazyna Janina; Olson, D; Pinkenburg, C H; Porile, N T; Rai, G; Ritter, H G; Romero, J; Scharenberg, R P; Schröder, L; Srivastava, B; Stone, N; Symons, T J M; Wang, S; Whitfield, J; Wienold, T; Witt, R; Wood, L; Yang, X; Zhang, W; Zhang, Y
1999-01-01
First measurements of the beam energy dependence of the two proton correlation function in central Au+Au collisions are performed by the E895 Collaboration at the BNL AGS. No significant changes with beam energy were observed. The imaging technique of Brown-Danielewicz is used in order to extract information about the space-time content of the proton source at freeze-out. Extracted source functions show peculiar enhancement at low relative separation.
Hamzavi, Majid
2012-01-01
The exact Dirac equation for the energy-dependent Coulomb (EDC) potential including a Coulomb-like tensor (CLT) potential has been studied in the presence of spin and pseudospin (p-spin) symmetries with arbitrary spin-orbit quantum number The energy eigenvalues and corresponding eigenfunctions are obtained in the framework of asymptotic iteration method (AIM). Some numerical results are obtained in the presence and absence of EDC and CLT potentials.
Optical properties of CdTe: Experiment and modeling
Adachi, Sadao; Kimura, Toshifumi; Suzuki, Norihiro
1993-09-01
The real epsilon(sub 1) and imaginary epsilon(sub 2) portions of the dielectric function of CdTe were measured by spectroscopic ellipsometry (SE) in the 1.1-5.6 eV photon-energy range at room temperature. The data obtained were analyzed using different theoretical models, namely the harmonic-oscillator approximation, the standard critical point, and the model dielectric function. These models include the E(sub 0), E(sub 0) + Delta(sub 0), E(sub 1), E(sub 1) + Delta(sub 1), and E(sub 2) gaps as the main dispersion mechanisms. The consequences were reported and of particular interest was the difference in the analyzed results between these theoretical models. Dielectric-related optical constants of CdTe, such as the complex refractive index, the absorption coefficient, and normal-incidence reflectivity, were also investigated.
Synthetic Modeling of Astronomical Closed Loop Adaptive Optics
Jolissaint, Laurent
2010-01-01
We present an analytical model of a single natural guide star astronomical adaptive optics system, in closed loop mode. The model is used to simulate the long exposure system point spread function, using the spatial frequency (or Fourier) approach, and complement an initial open loop model. Applications range from system design, science case analysis and AO data reduction. All the classical phase errors have been included: deformable mirror fitting error, wavefront sensor spatial aliasing, wavefront sensor noise, and the correlated anisoplanatic and servo-lag error. The model includes the deformable mirror spatial transfer function, and the actuator array geometry can be different from the wavefront sensor lenslet array geometry. We also include the dispersion between the sensing and the correction wavelengths. Illustrative examples are given at the end of the paper.
The Energy Dependence of Neutron Star Surface Modes and X-ray Burst Oscillations
Piro, A L; Piro, Anthony L.; Bildsten, Lars
2006-01-01
We calculate the photon energy dependence of the pulsed amplitude of neutron star (NS) surface modes. Simple approximations demonstrate that it depends most strongly on the bursting NS surface temperature. This result compares well with full integrations that include Doppler shifts from rotation and general relativistic corrections to photon propagation. We show that the energy dependence of type I X-ray burst oscillations agrees with that of a surface mode, lending further support to the hypothesis that they originate from surface waves. The energy dependence of the pulsed emission is rather insensitive to the NS inclination, mass and radius, or type of mode, thus hindering constraints on these parameters. We also show that, for this energy-amplitude relation, the majority of the signal (relative to the noise) comes in the 2-25 keV band, so that the current burst oscillation searches with the Rossi X-Ray Timing Explorer are close to optimal. The critical test of the mode hypothesis for X-ray burst oscillatio...
Fincham, W H A
2013-01-01
Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen
Gafchromic EBT3 film dosimetry in electron beams - energy dependence and improved film read-out.
Sipilä, Petri; Ojala, Jarkko; Kaijaluoto, Sampsa; Jokelainen, Ilkka; Kosunen, Antti
2016-01-01
For megavoltage photon radiation, the fundamental dosimetry characteristics of Gafchromic EBT3 film were determined in 60Co gamma ray beam with addition of experimental and Monte Carlo (MC)-simulated energy dependence of the film for 6 MV photon beam and 6 MeV, 9 MeV, 12 MeV, and 16 MeV electron beams in water phantom. For the film read-out, two phase correction of scanner sensitivity was applied: a matrix correction for scanning area and dose-dependent correction by iterative procedure. With these corrections, the uniformity of response can be improved to be within ± 50 pixel values (PVs). To improve the read-out accuracy, a procedure with flipped film orientations was established. With the method, scanner uniformity can be improved further and dust particles, scratches and/or dirt on scan-ner glass can be detected and eliminated. Responses from red and green channels were averaged for read-out, which decreased the effect of noise present in values from separate channels. Since the signal level with the blue channel is considerably lower than with other channels, the signal variation due to different perturbation effects increases the noise level so that the blue channel is not recommended to be used for dose determination. However, the blue channel can be used for the detection of emulsion thickness variations for film quality evaluations with unexposed films. With electron beams ranging from 6 MeV to 16 MeV and at reference measurement conditions in water, the energy dependence of the EBT3 film is uniform within 0.5%, with uncertainties close to 1.6% (k = 2). Including 6 MV photon beam and the electron beams mentioned, the energy dependence is within 1.1%. No notable differences were found between the experimental and MC-simulated responses, indicating negligible change in intrinsic energy dependence of the EBT3 film for 6 MV photon beam and 6 MeV-16 MeV electron beams. Based on the dosimetric characteristics of the EBT3 film, the read-out procedure established
Integrated modeling of the GMT laser tomography adaptive optics system
Piatrou, Piotr
2014-08-01
Laser Tomography Adaptive Optics (LTAO) is one of adaptive optics systems planned for the Giant Magellan Telescope (GMT). End-to-end simulation tools that are able to cope with the complexity and computational burden of the AO systems to be installed on the extremely large telescopes such as GMT prove to be an integral part of the GMT LTAO system development endeavors. SL95, the Fortran 95 Simulation Library, is one of the software tools successfully used for the LTAO system end-to-end simulations. The goal of SL95 project is to provide a complete set of generic, richly parameterized mathematical models for key elements of the segmented telescope wavefront control systems including both active and adaptive optics as well as the models for atmospheric turbulence, extended light sources like Laser Guide Stars (LGS), light propagation engines and closed-loop controllers. The library is implemented as a hierarchical collection of classes capable of mutual interaction, which allows one to assemble complex wavefront control system configurations with multiple interacting control channels. In this paper we demonstrate the SL95 capabilities by building an integrated end-to-end model of the GMT LTAO system with 7 control channels: LGS tomography with Adaptive Secondary and on-instrument deformable mirrors, tip-tilt and vibration control, LGS stabilization, LGS focus control, truth sensor-based dynamic noncommon path aberration rejection, pupil position control, SLODAR-like embedded turbulence profiler. The rich parameterization of the SL95 classes allows to build detailed error budgets propagating through the system multiple errors and perturbations such as turbulence-, telescope-, telescope misalignment-, segment phasing error-, non-common path-induced aberrations, sensor noises, deformable mirror-to-sensor mis-registration, vibration, temporal errors, etc. We will present a short description of the SL95 architecture, as well as the sample GMT LTAO system simulation
Advanced optical position sensors for magnetically suspended wind tunnel models
Lafleur, S.
1985-01-01
A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.
Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chung, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Gazdzicki, M; Genchev, V; Georgopoulos, G; Galadysz, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kikola, D; Kliemant, M; Kniege, S; Kolesnikov, V I; Kollegger, T; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Kresan, D; Laszlo, A; Lacey, R; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Peryt, W; Pikna, M; Pluta, J; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Slodkowski, M; Stefanek, G; Stock, R; Strabel, C; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Szuba, M; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Walodarczyk, Z; Yoo, I K; Zimányi, J
2008-01-01
Phi meson production is studied by the NA49 collaboration in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV beam energy. The data are compared to measurements at lower and higher energies and to microscopic and thermal models. The energy dependence of yields and spectral distributions is compatible with the assumption that partonic degrees of freedom set in at low SPS energies.
Mathematical model of an optically pumped molecular laser
Botha, LR
2009-07-01
Full Text Available pumped molecular laser Dr L R Botha, Dr C Bollig, D Esser, C Jacobs, D Preussler SAIP 2009 Durban Page 2 © CSIR 2008 www.csir.co.za Structure of talk • Introduction • Overview of HBr laser • Numerical Model • Comparison... µm laser ring oscillator & pre-amplifier 1.9 µm Optically Pumped Molecular laser @ 4 µm 95:5 HBr Absorption cell Fast detector 2.064 µm ± 1 nm Feedback control box Feedback loop 1 P ie zo m o u nt Fast detector Feedback loop 2 Gas...
Modeling of Self-Pumped Singly Resonant Optical Parametric Oscillator
Deng, Chengxian
2016-01-01
A model of the steady-state operating, self-pumped singly resonant optical parametric oscillator (SPSRO) has been developed. The characteristics of quasi three-level laser gain medium pumped longitudinally have been taken into account. The characteristics of standing wave cavity, reabsorption losses, focusing Gaussian beams of the pump laser, fundamental laser and signal wave have been considered in the analyses. Furthermore, The power characteristics of threshold and efficiency have been analyzed, employing a Yb3+-doped periodically poled lithium niobate co-doped with MgO (Yb3+:MgO:PPLN) as the medium of laser gain and second-order nonlinear crystal.
Fluctuations and entropy in models of quantum optical resonance
Phoenix, S. J. D.; Knight, P. L.
1988-09-01
We use variances, entropy, and the Shannon entropy to analyse the fluctuations and quantum evolution of various simple models of quantum optical resonance. We discuss at length the properties of the single-mode radiation field coupled to a single two-level atom, and then extend our analysis to describe the micromaser in which a cavity mode is repeatedly pumped by a succession of atoms passing through the cavity. We also discuss the fluctuations in the single-mode laser theory of Scully and Lamb.
Purely optical navigation with model-based state prediction
Sendobry, Alexander; Graber, Thorsten; Klingauf, Uwe
2010-10-01
State-of-the-art Inertial Navigation Systems (INS) based on Micro-Electro-Mechanical Systems (MEMS) have a lack of precision especially in GPS denied environments like urban canyons or in pure indoor missions. The proposed Optical Navigation System (ONS) provides bias free ego-motion estimates using triple redundant sensor information. In combination with a model based state prediction our system is able to estimate velocity, position and attitude of an arbitrary aircraft. Simulating a high performance flow-field estimator the algorithm can compete with conventional low-cost INS. By using measured velocities instead of accelerations the system states drift behavior is not as distinctive as for an INS.
Numerical modelling of multimode fibre-optic communication lines
Sidelnikov, O. S.; Sygletos, S.; Ferreira, F.; Fedoruk, M. P.
2016-01-01
The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong coupling regime provides a lower EVM level than the weak coupling one.
Kharab Rajesh
2014-03-01
Full Text Available We have investigated the relative importance of the energy dependence of diffuseness parameter and barrier position in the description of the fusion excitation function data of some heavy ion systems in near barrier energy region. The effects of the energy dependent diffuseness parameter are found to be much more prominent in comparison to those of barrier position.
Modeling of laser-induced damage and optic usage at the National Ignition Facility
Liao, Zhi M.; Nostrand, Mike; Carr, Wren; Bude, Jeff; Suratwala, Tayyab I.
2016-07-01
Modeling of laser-induced optics damage has been introduced to benchmark existing optic usage at the National Ignition Facility (NIF) which includes the number of optics exchanged for damage repair. NIF has pioneered an optics recycle strategy to allow it to run the laser at capacity since fully commissioned in 2009 while keeping the cost of optics usage manageable. We will show how the damage model is being used to evaluate strategies to streamline our optics loop efficiency, as we strive to increase the laser shot rate without increasing operating costs.
Tonkyn, Russell G.; Danby, Tyler O.; Birnbaum, Jerome L.; Taubman, Matthew S.; Bernacki, Bruce E.; Johnson, Timothy J.; Myers, Tanya L.
2017-05-01
The complex optical refractive index contains the optical constants, n(ῦ)and k(ῦ), which correspond to the dispersion and absorption of light within a medium, respectively. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. We have developed improved protocols based on the use of multiple path lengths to determine the optical constants for dozens of liquids, including organic and organophosphorous compounds. Detailed description of the protocols to determine the infrared indices will be presented, along with preliminary results using the constants with their applications to optical modeling.
Tonkyn, Russell G.; Danby, Tyler O.; Birnbaum, Jerome C.; Taubman, Matthew S.; Bernacki, Bruce E.; Johnson, Timothy J.; Myers, Tanya L.
2017-05-03
The complex optical refractive index contains the optical constants, n($\\tilde{u}$)and k($\\tilde{u}$), which correspond to the dispersion and absorption of light within a medium, respectively. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. We have developed improved protocols based on the use of multiple path lengths to determine the optical constants for dozens of liquids, including organic and organophosphorous compounds. Detailed description of the protocols to determine the infrared indices will be presented, along with preliminary results using the constants with their applications to optical modeling.
2008-10-01
Remote sensing of ocean color provides synoptic surface ocean bio -optical properties but is limited to real-time or climatological applications. Many...this, we couple satellite imagery with numerical circulation models to provide short-term (24-48 hr) forecasts of bio -optical properties. These are...physical processes control the bio -optical distribution patterns. We compare optical forecast results from three Navy models and two advection
Energy-dependent Orbital Modulation of X-rays and Constraints on Emission of the Jet in Cyg X-3
Zdziarski, Andrzej A.; Maitra, Chandreyee; Frankowski, Adam; Skinner, Gerald K.; Misra, Ranjeev
2012-01-01
We study orbital modulation of X-rays from Cyg X-3, using data from Swift, INTEGRAL and RXTE. Using the wealth of the presently available data and an improved averaging method, we obtain energy-dependent folded and averaged light curves with unprecedented accuracy. We find that above 5 keV, the modulation depth decreases with the increasing energy, which is consistent with the modulation being caused by both bound-free absorption and Compton scattering in the stellar wind of the donor, with minima corresponding to the highest optical depth, which occurs around the superior conjunction. We find a decrease of the depth below 3 keV, which appears to be due to re-emission of the absorbed continuum by the wind in soft X-ray lines. Based on the shape of the folded light curves, any X-ray contribution from the jet in Cyg X-3, which emits ?-rays detected at energies > 0.1 GeV in soft spectral states, is found to be minor up to 100 keV. This implies the presence of a rather sharp low-energy break in the jet MeV-range spectrum.We also calculate phase-resolved RXTE X-ray spectra, and show the difference between the spectra corresponding to phases around the superior and inferior conjunctions can indeed be accounted for by a combined effect of bound-free absorption in an ionized medium and Compton scattering.
Optical properties of soot particles: measurement - model comparison
Forestieri, S.; Lambe, A. T.; Lack, D.; Massoli, P.; Cross, E. S.; Dubey, M.; Mazzoleni, C.; Olfert, J.; Freedman, A.; Davidovits, P.; Onasch, T. B.; Cappa, C. D.
2013-12-01
Soot, a product of incomplete combustion, plays an important role in the earth's climate system through the absorption and scattering of solar radiation. In order to accurately model the direct radiative impact of black carbon (BC), the refractive index and shape dependent scattering and absorption characteristics must be known. At present, the assumed shape remains highly uncertain because BC particles are fractal-like, being agglomerates of smaller (20-40 nm) spherules, yet traditional optical models such as Mie theory typically assume a spherical particle morphology. To investigate the ability of various optical models to reproduce observed BC optical properties, we measured light absorption and extinction coefficients of methane and ethylene flame soot particles. Optical properties were measured by multiple instruments: absorption by a dual cavity ringdown photoacoustic spectrometer (CRD-PAS), absorption and scattering by a 3-wavelength photoacoustic/nephelometer spectrometer (PASS-3) and extinction and scattering by a cavity attenuated phase shift spectrometer (CAPS). Soot particle mass was quantified using a centrifugal particle mass analyzer (CPMA) and mobility size was measured with a scanning mobility particle sizer (SMPS). Measurements were made for nascent soot particles and for collapsed soot particles following coating with dioctyl sebacate or sulfuric acid and thermal denuding to remove the coating. Wavelength-dependent refractive indices for the sampled particles were derived by fitting the observed absorption and extinction cross-sections to spherical particle Mie theory and Rayleigh-Debye-Gans theory. The Rayleigh-Debye-Gans approximation assumes that the absorption properties of soot are dictated by the individual spherules and neglects interaction between them. In general, Mie theory reproduces the observed absorption and extinction cross-sections for particles with volume equivalent diameters (VED) VED > ~160 nm. The discrepancy is most
Fincham, W H A
2013-01-01
Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st
Multiscale modeling and computation of optically manipulated nano devices
Bao, Gang; Liu, Di; Luo, Songting
2016-07-01
We present a multiscale modeling and computational scheme for optical-mechanical responses of nanostructures. The multi-physical nature of the problem is a result of the interaction between the electromagnetic (EM) field, the molecular motion, and the electronic excitation. To balance accuracy and complexity, we adopt the semi-classical approach that the EM field is described classically by the Maxwell equations, and the charged particles follow the Schrödinger equations quantum mechanically. To overcome the numerical challenge of solving the high dimensional multi-component many-body Schrödinger equations, we further simplify the model with the Ehrenfest molecular dynamics to determine the motion of the nuclei, and use the Time-Dependent Current Density Functional Theory (TD-CDFT) to calculate the excitation of the electrons. This leads to a system of coupled equations that computes the electromagnetic field, the nuclear positions, and the electronic current and charge densities simultaneously. In the regime of linear responses, the resonant frequencies initiating the out-of-equilibrium optical-mechanical responses can be formulated as an eigenvalue problem. A self-consistent multiscale method is designed to deal with the well separated space scales. The isomerization of azobenzene is presented as a numerical example.
GAUTAM MANJEET SINGH
2016-05-01
Limitations of the static Woods–Saxon potential and the applicability of the energy dependent Woods–Saxon potential (EDWSP) model within the framework of one-dimensional Wong formula to explore the sub-barrier fusion data are highlighted. The inelastic surface excitations of the fusing nuclei are found to be dominating in the enhancement of sub-barrier fusion excitation function data and the effects of such dominant vibrational states are exploited through the coupled channel calculations obtained by using the code CCFULL. It is worth mentioning here that the influence of multiphonon vibrational states of the reactants can be simulated by introducing the energy dependence in the nucleus–nucleus potential.
Simulations of Keratoconus Patient Vision with Optical Eye Modeling
Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Shi, Lei; Wang, Ming
2007-11-01
Keratoconus (KC) is an eye condition that involves progressive corneal thinning. Pushed by the intraocular pressure, the weakened cornea bulges outward and creates an irregular surface shape. The result is degraded vision that is difficult to correct with regular eye glasses or contact lens. In this study we use the optical lens design software, ZeMax, and patient data including cornea topography and refraction prescription to construct KC eye models. The variation of KC ``cone height'' on the cornea is used to simulate KC progression. The consequent patients' night vision and Snellen letter chart vision at 20 feet are simulated using these anatomically accurate 3-dimensional models. 100 million rays are traced for each image simulation. Animated results illustrate the change of KC visual acuity with the progression of disease. This simulation technique provides a comprehensive tool for medical training and patient consultation/education.
Protein folding: the optically induced electronic excitations model
Jeknic-Dugic, J [Department of Physics, Faculty of Science, Nis (Serbia)], E-mail: jjeknic@pmf.ni.ac.yu
2009-07-15
The large-molecules conformational transitions problem (the 'protein folding problem') is an open issue of vivid current science research work of fundamental importance for a number of modern science disciplines as well as for nanotechnology. Here, we elaborate the recently proposed quantum-decoherence-based approach to the issue. First, we emphasize a need for detecting the elementary quantum mechanical processes (whose combinations may give a proper description of the realistic experimental situations) and then we design such a model. As distinct from the standard approach that deals with the conformation system, we investigate the optically induced transitions in the molecule electrons system that, in effect, may give rise to a conformation change in the molecule. Our conclusion is that such a model may describe the comparatively slow conformational transitions.
Structural model constructing for optical handwritten character recognition
Khaustov, P. A.; Spitsyn, V. G.; Maksimova, E. I.
2017-02-01
The article is devoted to the development of the algorithms for optical handwritten character recognition based on the structural models constructing. The main advantage of these algorithms is the low requirement regarding the number of reference images. The one-pass approach to a thinning of the binary character representation has been proposed. This approach is based on the joint use of Zhang-Suen and Wu-Tsai algorithms. The effectiveness of the proposed approach is confirmed by the results of the experiments. The article includes the detailed description of the structural model constructing algorithm’s steps. The proposed algorithm has been implemented in character processing application and has been approved on MNIST handwriting characters database. Algorithms that could be used in case of limited reference images number were used for the comparison.
Simulation of energy-dependent electron diffusion processes in the Earth's outer radiation belt
Ma, Q.; Li, W.; Thorne, R. M.; Nishimura, Y.; Zhang, X.-J.; Reeves, G. D.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Henderson, M. G.; Spence, H. E.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Angelopoulos, V.
2016-05-01
The radial and local diffusion processes induced by various plasma waves govern the highly energetic electron dynamics in the Earth's radiation belts, causing distinct characteristics in electron distributions at various energies. In this study, we present our simulation results of the energetic electron evolution during a geomagnetic storm using the University of California, Los Angeles 3-D diffusion code. Following the plasma sheet electron injections, the electrons at different energy bands detected by the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron Proton Telescope (REPT) instruments on board the Van Allen Probes exhibit a rapid enhancement followed by a slow diffusive movement in differential energy fluxes, and the radial extent to which electrons can penetrate into depends on energy with closer penetration toward the Earth at lower energies than higher energies. We incorporate radial diffusion, local acceleration, and loss processes due to whistler mode wave observations to perform a 3-D diffusion simulation. Our simulation results demonstrate that chorus waves cause electron flux increase by more than 1 order of magnitude during the first 18 h, and the subsequent radial extents of the energetic electrons during the storm recovery phase are determined by the coupled radial diffusion and the pitch angle scattering by EMIC waves and plasmaspheric hiss. The radial diffusion caused by ULF waves and local plasma wave scattering are energy dependent, which lead to the observed electron flux variations with energy dependences. This study suggests that plasma wave distributions in the inner magnetosphere are crucial for the energy-dependent intrusions of several hundred keV to several MeV electrons.
Nogami, Keisuke; Sakai, Yasuhiro; Mineta, Shota [Department of Physics, Toho University, Miyama, Funabashi, Chiba 274-8510 (Japan); Kato, Daiji; Murakami, Izumi [National Institute for Fusion Science, Toki, Gifu 509-5292, Japan and Department of Fusion Science, School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies), Toki, Gifu 509-5292 (Japan); Sakaue, Hiroyuki A. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Kenmotsu, Takahiro [Department of Biomedical Engineering, Faculty of Life and Medical Sciences, Doshisha University, Tatara-Miyakodani, Kyotanabe, Kyoto 610-0394 (Japan); Furuya, Kenji [Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Motohashi, Kenji, E-mail: motohashi@toyo.jp [Department of Biomedical Engineering, Faculty of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan and Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)
2015-11-15
Visible emission spectra were acquired from neutral atoms sputtered by 35–60 keV Kr{sup +} ions from a polycrystalline tungsten surface. Mean velocities of excited tungsten atoms in seven different 6p states were also obtained via the dependence of photon intensities on the distance from the surface. The average velocities parallel to the surface normal varied by factors of 2–4 for atoms in the different 6p energy levels. However, they were almost independent of the incident ion kinetic energy. The 6p-level energy dependence indicated that the velocities of the excited atoms were determined by inelastic processes that involve resonant charge exchange.
Pickering, Luke
2016-01-01
We present a Monte Carlo truth study examining nuclear effects in charged-current neutrino interactions using observables constructed in the transverse plane. Three distributions are introduced that show very weak dependence on neutrino flux and its associated uncertainty. Measurements comparing these distributions between quasi-elastic-like and single charged pion final states will provide new constraints of nuclear effects. It is suggested that the on-axis position in the NuMI beam provides the correct flux to take advantage of this reduced energy dependence in measuring nuclear effect-generated transverse imbalances.
Scaling-law for the energy dependence of anatomic power spectrum in dedicated breast CT
Vedantham, Srinivasan; Shi, Linxi; Glick, Stephen J.; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)
2013-01-15
Purpose: To determine the x-ray photon energy dependence of the anatomic power spectrum of the breast when imaged with dedicated breast computed tomography (CT). Methods: A theoretical framework for scaling the empirically determined anatomic power spectrum at one x-ray photon energy to that at any given x-ray photon energy when imaged with dedicated breast CT was developed. Theory predicted that when the anatomic power spectrum is fitted with a power curve of the form k f{sup -{beta}}, where k and {beta} are fit coefficients and f is spatial frequency, the exponent {beta} would be independent of x-ray photon energy (E), and the amplitude k scales with the square of the difference in energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues. Twenty mastectomy specimens based numerical phantoms that were previously imaged with a benchtop flat-panel cone-beam CT system were converted to 3D distribution of glandular weight fraction (f{sub g}) and were used to verify the theoretical findings. The 3D power spectrum was computed in terms of f{sub g} and after converting to linear attenuation coefficients at monoenergetic x-ray photon energies of 20-80 keV in 5 keV intervals. The 1D power spectra along the axes were extracted and fitted with a power curve of the form k f{sup -{beta}}. The energy dependence of k and {beta} were analyzed. Results: For the 20 mastectomy specimen based numerical phantoms used in the study, the exponent {beta} was found to be in the range of 2.34-2.42, depending on the axis of measurement. Numerical simulations agreed with the theoretical predictions that for a power-law anatomic spectrum of the form k f{sup -{beta}}, {beta} was independent of E and k(E) =k{sub 1}[{mu}{sub g}(E) -{mu}{sub a}(E)]{sup 2}, where k{sub 1} is a constant, and {mu}{sub g}(E) and {mu}{sub a}(E) represent the energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues, respectively. Conclusions: Numerical
Dual permeability FEM models for distributed fiber optic sensors development
Aguilar-López, Juan Pablo; Bogaard, Thom
2017-04-01
Fiber optic cables are commonly known for being robust and reliable mediums for transferring information at the speed of light in glass. Billions of kilometers of cable have been installed around the world for internet connection and real time information sharing. Yet, fiber optic cable is not only a mean for information transfer but also a way to sense and measure physical properties of the medium in which is installed. For dike monitoring, it has been used in the past for detecting inner core and foundation temperature changes which allow to estimate water infiltration during high water events. The DOMINO research project, aims to develop a fiber optic based dike monitoring system which allows to directly sense and measure any pore pressure change inside the dike structure. For this purpose, questions like which location, how many sensors, which measuring frequency and which accuracy are required for the sensor development. All these questions may be initially answered with a finite element model which allows to estimate the effects of pore pressure change in different locations along the cross section while having a time dependent estimation of a stability factor. The sensor aims to monitor two main failure mechanisms at the same time; The piping erosion failure mechanism and the macro-stability failure mechanism. Both mechanisms are going to be modeled and assessed in detail with a finite element based dual permeability Darcy-Richards numerical solution. In that manner, it is possible to assess different sensing configurations with different loading scenarios (e.g. High water levels, rainfall events and initial soil moisture and permeability conditions). The results obtained for the different configurations are later evaluated based on an entropy based performance evaluation. The added value of this kind of modelling approach for the sensor development is that it allows to simultaneously model the piping erosion and macro-stability failure mechanisms in a time
Hansen, Anja; Krueger, Alexander; Ripken, Tammo
2013-03-01
In ophthalmic microsurgery tissue dissection is achieved using femtosecond laser pulses to create an optical breakdown. For vitreo-retinal applications the irradiance distribution in the focal volume is distorted by the anterior components of the eye causing a raised threshold energy for breakdown. In this work, an adaptive optics system enables spatial beam shaping for compensation of aberrations and investigation of wave front influence on optical breakdown. An eye model was designed to allow for aberration correction as well as detection of optical breakdown. The eye model consists of an achromatic lens for modeling the eye's refractive power, a water chamber for modeling the tissue properties, and a PTFE sample for modeling the retina's scattering properties. Aberration correction was performed using a deformable mirror in combination with a Hartmann-Shack-sensor. The influence of an adaptive optics aberration correction on the pulse energy required for photodisruption was investigated using transmission measurements for determination of the breakdown threshold and video imaging of the focal region for study of the gas bubble dynamics. The threshold energy is considerably reduced when correcting for the aberrations of the system and the model eye. Also, a raise in irradiance at constant pulse energy was shown for the aberration corrected case. The reduced pulse energy lowers the potential risk of collateral damage which is especially important for retinal safety. This offers new possibilities for vitreo-retinal surgery using femtosecond laser pulses.
Y. H. Lee
2014-09-01
Full Text Available The TwO-Moment Aerosol Sectional microphysics model (TOMAS has been integrated into the state-of-the-art general circulation model, GISS ModelE2. TOMAS has the flexibility to select a size resolution as well as the lower size cutoff. A computationally efficient version of TOMAS is used here, which has 15 size bins covering 3 nm to 10 μm aerosol dry diameter. For each bin, it simulates the total aerosol number concentration and mass concentrations of sulphate, pure elementary carbon (hydrophobic, mixed elemental carbon (hydrophilic, hydrophobic organic matter, hydrophilic organic matter, sea salt, mineral dust, ammonium, and aerosol-associated water. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the TOMAS model is compared to the default aerosol model in ModelE2, which is a bulk aerosol model. Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement with observations of sulphur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as the bulk aerosol model cannot capture the observed vertical distribution of sulphur dioxide over the Pacific Ocean possibly due to overly strong convective transport. The TOMAS model successfully captures observed aerosol number concentrations and cloud condensation nuclei concentrations. Anthropogenic aerosol burdens in the bulk aerosol model running in the same host model as TOMAS (ModelE2 differ by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. Larger differences are found
Modeling silica aerogel optical performance by determining its radiative properties
Lin Zhao
2016-02-01
Full Text Available Silica aerogel has been known as a promising candidate for high performance transparent insulation material (TIM. Optical transparency is a crucial metric for silica aerogels in many solar related applications. Both scattering and absorption can reduce the amount of light transmitted through an aerogel slab. Due to multiple scattering, the transmittance deviates from the Beer-Lambert law (exponential attenuation. To better understand its optical performance, we decoupled and quantified the extinction contributions of absorption and scattering separately by identifying two sets of radiative properties. The radiative properties are deduced from the measured total transmittance and reflectance spectra (from 250 nm to 2500 nm of synthesized aerogel samples by solving the inverse problem of the 1-D Radiative Transfer Equation (RTE. The obtained radiative properties are found to be independent of the sample geometry and can be considered intrinsic material properties, which originate from the aerogel’s microstructure. This finding allows for these properties to be directly compared between different samples. We also demonstrate that by using the obtained radiative properties, we can model the photon transport in aerogels of arbitrary shapes, where an analytical solution is difficult to obtain.
Photon energy dependence of circular dichroism of the Au(111) surface state
Ärrälä, M.; Nieminen, J.; Braun, J.; Ebert, H.; Lindroos, M.
2013-11-01
Through relativistic photoemission calculations for the Au(111) surface state at the Fermi level, we study the photon energy dependence of circular dichroism. The dichromatic signal (DS) pattern changes 23 times with photon energies between 7 and 100 eV, and we have found 13 different patterns in the k∥ map at the Fermi level for the DS from the Au(111) surface state with normal incidence light. We show that the photon energy dependence of DS is very complex even in the simplest case. The sign change in the circular dichroism as a function of photon energy is related to the relative phases of the complex expansion coefficients of different outgoing partial waves in a time-reversed low-energy electron diffraction state. With off-normal incidence, the z component of the incoming photon field is dominant, and the fine structure seen in the DS in the normal incidence case is lost very rapidly, moving from a normal to an off-normal incidence. We also report that the Rashba split surface state of Au(111) has a significant component of d-type orbital due to relativistic effects and the computational setup used.
Modelling the optical properties of aerosols in a chemical transport model
Andersson, E.; Kahnert, M.
2015-12-01
According to the IPCC fifth assessment report (2013), clouds and aerosols still contribute to the largest uncertainty when estimating and interpreting changes to the Earth's energy budget. Therefore, understanding the interaction between radiation and aerosols is both crucial for remote sensing observations and modelling the climate forcing arising from aerosols. Carbon particles are the largest contributor to the aerosol absorption of solar radiation, thereby enhancing the warming of the planet. Modelling the radiative properties of carbon particles is a hard task and involves many uncertainties arising from the difficulties of accounting for the morphologies and heterogeneous chemical composition of the particles. This study aims to compare two ways of modelling the optical properties of aerosols simulated by a chemical transport model. The first method models particle optical properties as homogeneous spheres and are externally mixed. This is a simple model that is particularly easy to use in data assimilation methods, since the optics model is linear. The second method involves a core-shell internal mixture of soot, where sulphate, nitrate, ammonia, organic carbon, sea salt, and water are contained in the shell. However, by contrast to previously used core-shell models, only part of the carbon is concentrated in the core, while the remaining part is homogeneously mixed with the shell. The chemical transport model (CTM) simulations are done regionally over Europe with the Multiple-scale Atmospheric Transport and CHemistry (MATCH) model, developed by the Swedish Meteorological and Hydrological Institute (SMHI). The MATCH model was run with both an aerosol dynamics module, called SALSA, and with a regular "bulk" approach, i.e., a mass transport model without aerosol dynamics. Two events from 2007 are used in the analysis, one with high (22/12-2007) and one with low (22/6-2007) levels of elemental carbon (EC) over Europe. The results of the study help to assess the
Experimentation and modeling of organic photocontamination on lithographic optics
Kunz, Roderick R.; Liberman, Vladimir; Downs, Deanna K.
2000-07-01
Photodeposition of organic films on transparent substrates irradiated in the presence of trace levels of hydrocarbons has been experimentally investigated and a model is presented that describes the film growth behavior. The efficacy of a given organic precursor at forming a deposit is proportional to the product of its surface coverage and by its photon absorption cross section. These measurement are important in predicting the transmission characteristics of lithographic optics operating at 157-, 193-, and 248-nm wavelength. For example, a lens element irradiated continuously for one year in the presence of 1 part per billion of t-butyl benzene would exhibit a transmission of approximately 87 percent at 193 nm. The effects of oxygen- containing ambients are also documented, and methods for elimination and/or prevention of organic contamination are suggested.
Coupled-channel optical model potential for rare earth nuclei
Herman, M; Palumbo, A; Dietrich, F S; Brown, D; Hoblit, S
2013-01-01
Inspired by the recent work by Dietrich et al., substantiating validity of the adiabatic assumption in coupled-channel calculations, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on statically deformed nuclei. The generalization consists in adding the coupling of the ground state rotational band, deforming the potential by introducing appropriate quadrupole and hexadecupole deformation and correcting the OMP radius to preserve volume integral of the spherical OMP. We choose isotopes of three rare-earth elements (W, Ho, Gd), which are known to be nearly perfect rotors, to perform a consistent test of our conjecture on integrated cross sections as well as on angular distributions for elastic and inelastic neutron scattering. When doing this we employ the well-established Koning-Delaroche global spherical potential and experimentally determined deformations without any adjustments. We observe a dramatically improved a...
Model of a thin film optical fiber fluorosensor
Egalon, Claudio O.; Rogowski, Robert S.
1991-03-01
The efficiency of core-light injection from sources in the cladding of an optical fiber is modeled analytically by means of the exact field solution of a step-profile fiber. The analysis is based on the techniques by Marcuse (1988) in which the sources are treated as infinitesimal electric currents with random phase and orientation that excite radiation fields and bound modes. Expressions are developed based on an infinite cladding approximation which yield the power efficiency for a fiber coated with fluorescent sources in the core/cladding interface. Marcuse's results are confirmed for the case of a weakly guiding cylindrical fiber with fluorescent sources uniformly distributed in the cladding, and the power efficiency is shown to be practically constant for variable wavelengths and core radii. The most efficient fibers have the thin film located at the core/cladding boundary, and fibers with larger differences in the indices of refraction are shown to be the most efficient.
Microscopic model for all optical switching in ferromagnets
Cornelissen, T. D.; Córdoba, R.; Koopmans, B.
2016-04-01
The microscopic mechanism behind the all optical switching (AOS) in ferromagnets has triggered intense scientific debate. Here, the microscopic three-temperature model is utilized to describe AOS in a perpendicularly magnetized ferromagnetic Co/Pt system. We demonstrate that AOS in such a ferromagnet can be explained with the Inverse Faraday Effect (IFE). The influence of the strength and lifetime of the IFE induced field pulse on the switching process are investigated. We found that because of strong spin-orbit coupling, the minimal lifetime of the IFE needed to obtain switching is of the order of 0.1 ps, which is shorter than previously assumed. Moreover, spatial images of the domain pattern after AOS in Co/Pt, as well as their dependence on applying an opposite magnetic field, are qualitatively reproduced.
Ionization Modeling Astrophysical Gaseous Structures. I. The Optically Thin Regime
Churchill, Christopher W; Medina, Amber; Vliet, Jacob R Vander
2014-01-01
We present a code for modelling the ionization conditions of optically thin astrophysical gas structures. Given the gas hydrogen density, equilibrium temperature, elemental abundances, and the ionizing spectrum, the code solves the equilibrium ionization fractions and number densities for all ions from hydrogen to zinc. The included processes are photoionization, Auger ionization, direct collisional ionization, excitation auto-ionization, charge exchange ionization, two-body radiative recombination, dielectronic recombination, and charge exchange recombination. The ionizing spectrum can be generalized to include the ultraviolet background (UVB) and/or Starburst99 stellar populations of various masses, ages, metallicities, and distances. The ultimate goal with the code is to provide fast computation of the ionization conditions of gas in N-body + hydrodynamics cosmological simulations, in particular adaptive mesh refinement codes, in order to facilitate absorption line analysis of the simulated gas for compari...
Some optical and dynamical phenomena in the Rindler model
Birsin, E
2014-01-01
In Rindler's model of a uniformly accelerated reference frame we analyze the apparent shape of rods and marked light rays for the case that the observers as well as the rods and the sources of light are at rest with respect to the Rindler observers. Contrary to the expectation suggested by the strong principle of equivalence, there is no apparent "bending down" of a light ray with direction transversal to the direction of acceleration, but a straight rod oriented orthogonal to the direction of acceleration appears bended "upwards". These optical phenomena are in accordance with the dynamical experience of observers guided by a straight track or a track curved in the same way as the marked light ray, respectively: While the former observer feels a centrifugal force directed "downwards", the centrifugal force for the latter vanishes. The properties of gyroscope transport along such tracks are correspondingly.
MILES extended : Stellar population synthesis models from the optical to the infrared
Rock, B.; Vazdekis, A.; Ricciardelli, E.; Peletier, R. F.; Knapen, J. H.; Falcon-Barroso, J.
2016-01-01
We present the first single-burst stellar population models, which covers the optical and the infrared wavelength range between 3500 and 50 000 angstrom and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical wi
Modeling the reverberation of optical polarization in AGN
Lobos, P Andrea Rojas; Marin, Frederic
2016-01-01
According to the standard paradigm, the strong and compact luminosity of active galactic nuclei (AGN) is due to multi-temperature black body emission originating from an accretion disk formed around a supermassive black hole. This central engine is thought to be surrounded by a dusty region along the equatorial plane and by ionized winds along the poles. The innermost regions cannot yet be resolved neither in the optical nor in the infrared and it is fair to say that we still lack a satisfactory understanding of the physical processes, geometry and composition of the central (sub-parsec) components of AGN. Like spectral or polarimetric observations, the reverberation data needs to be modeled in order to infer constraints on the AGN geometry (such as the inner radius or the half-opening angle of the dusty torus). In this research note, we present preliminary modeling results using a time-dependent Monte Carlo method to solve the radiative transfer in a simplified AGN set up. We investigate different model conf...
LIU Ji-yan; SI Yong-min
2004-01-01
Fibre-optic magnetic sensors with magnetostrictive films are used as all-fibre Mach-Zehnder interferometer to detect the optical phase shift, which is caused by the magnetostriction-induced strains transferred from the msgnetostrictive film to the fibre. A theoretical model based on the plane strain approximation and uniform axial strain is developed to determine the magneto-mechano-optical transfer relations in this kind of sensors. The expression for the model is presented as well as relation of the phase shift in the fibre to the magnetic and elastic properties of the magnetostrictive film coated on the fibre. And from the model, the thickness of the film has significant influence on the phase shift.
Energy Dependent time lags in the Seyfert 1 galaxy NGC 4593
Sriram, K; Rao, A R
2009-01-01
We investigate the energy-time lag dependence of the source NGC 4593 using XMM-{\\it Newton}/EPIC-pn data. We found that the time lag dependency is linear in nature with respect to the logarithm of different energy bands. We also investigate the frequency dependent time lags and identify that at some frequency range (5 $\\times$ 10$^{-5}$ Hz -- 2 $\\times$ 10$^{-4}$ Hz) the X-ray emission is highly coherent, mildly frequency dependent and very strongly energy dependent. These observations can be explained in the frame work of the thermal Comptonization process and they indicate a truncated accretion disk very close to the black hole. We discuss the plausible spectral state to explain the phenomenon and conclude that the observed properties bear a close resemblance to the intermediate state or the steep power-law state, found in galactic black hole sources.
Compendium of energy-dependent sensitivity profiles for the TRX-2 thermal lattice
Tomlinson, E.T.; Lucius, J.L.; Drischler, J.D.
1978-03-01
Energy-dependent sensitivity profiles for five responses calculated for the TRX-2 thermal lattice with the ORNL sensitivity code system FORSS are presented here both in graphical form and in SENPRO format. The responses are the multiplication factor, k/sub eff/; the ratio of epithermal-to-thermal captures in /sup 238/U, /sup 28/rho; the ratio of epithermal-to-thermal fissions in /sup 235/U, /sup 25/delta; the ratio of fissions in /sup 238/U to fissions in /sup 235/U, /sup 28/delta; and the ratio of captures in /sup 238/U to fissions in /sup 235/U, CR. A summary table of the total sensitivities is also presented.
Energy dependence of potential barriers and its effect on fusion cross-sections
Umar, A S; Oberacker, V E
2014-01-01
Couplings between relative motion and internal structures are known to affect fusion barriers by dynamically modifying the densities of the colliding nuclei. The effect is expected to be stronger at energies near the barrier top, where changes in density have longer time to develop than at higher energies. Quantitatively, modern TDHF calculations are able to predict realistic fusion thresholds. However, the evolution of the potential barrier with bombarding energy remains to be confronted with the experimental data. The aim is to find signatures of the energy dependence of the barrier by comparing fusion cross-sections calculated from potentials obtained at different bombarding energies with the experimental data. This comparison is made for the $^{40}$Ca+$^{40}$Ca and $^{16}$O+$^{208}$Pb systems. Fusion cross-sections are computed from potentials calculated with the density-constrained TDHF method. The couplings decrease the barrier at low-energy in both cases. A deviation from the Woods-Saxon nuclear potent...
Collision energy dependence of He and Ne capture by C sup + sub 60
Campbell, E.E.B.; Ehlich, R.; Hielscher, A.; Frazao, J.M.A.; Hertel, I.V. (Freiburg Univ. (Germany). Fakultaet fuer Physik Freiburg Univ. (Germany). Freiburger Materialforschungszentrum (FMF))
1992-04-01
Recently, reports of the formation of endohedral cluster compounds He{alpha}C{sup +}{sub n} and Ne{alpha}C{sup +}{sub n-4} (n even and {<=}60) have been published for high energy collisions between C{sup +}{sub 60} and rare gases. Here we present the collision energy dependence for the formation of He{alpha}C{sup +}{sub 60} and Ne{alpha}C{sup +}{sub 60} in the region of the energetic threshold for the capture process. The threshold for He capture lies at 6{+-}2 eV in the centre of mass reference frame whereas that for Ne lies somewhat higher at 9{+-}1 eV. ({alpha} means endohedral fulleren compounds.) (orig.).
Energy dependence of the charged multiplicity in deep inelastic scattering at HERA
Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)
2008-03-15
The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 38.6 pb{sup -1}. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The KNO-scaling properties of the data were investigated and the energy dependence was studied using different energy scales. The data are compared to results obtained in e{sup +}e{sup -} collisions and to previous DIS measurements as well as to leading-logarithm parton-shower Monte Carlo predictions. (orig.)
Measurement of the energy dependence of the total photon-proton cross section at HERA
Abramowicz, H. [Tel Aviv Univ. (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences; Univ. Coll. London (United Kingdom); Krakow Univ. of Technology (Poland). Faculty of Physics, Mathematics and Applied Computer Science; Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)
2010-10-15
The energy dependence of the photon-proton total cross section, {sigma}{sub tot}{sup {gamma}}{sup p}, was determined from e{sup +}p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the {gamma}p system in the range 194
Hendi, S. H.; Talezadeh, M. S.
2017-01-01
Regarding the wide applications of dilaton gravity in the presence of electrodynamics, we introduce a suitable Lagrangian for the coupling of dilaton with gauge field. There are various Lagrangians which show the coupling between scalar fields and electrodynamics with correct special situations. In this paper, taking into account conformal transformation of Brans-Dicke theory with an electrodynamics Lagrangian, we show that how scalar field should couple with electrodynamics in dilaton gravity. In other words, in order to introduce a correct Lagrangian of dilaton gravity, one should check at least two requirements: compatibility with Brans-Dicke theory and appropriate special situations. Finally, we apply the mentioned method to obtain analytical solutions of dilaton-Born-Infeld and Brans-Dicke-Born-Infeld theories with energy dependent spacetime.
Hendi, S H
2016-01-01
Regarding the wide applications of dilaton gravity in the presence of electrodynamics, we introduce a suitable Lagrangian for the coupling of dilaton with gauge field. There are various Lagrangians which show the coupling between scalar fields and electrodynamics with correct special situations. In this paper, taking into account conformal transformation of Brans-Dick theory with an electrodynamics Lagrangian, we show that how the scalar field should couple with electrodynamics in dilaton gravity. In other words, in order to introduce a correct Lagrangian of dilaton gravity, one should check at least two requirements: compatibility with Brans-Dick theory and appropriate special situations. Finally, we apply the mentioned method to obtain analytical solutions of dilaton-Born-Infeld and Brans-Dicke-Born-Infeld theories with energy dependent spacetime.
Energy Dependence of Slope Parameter in Elastic Nucleon-Nucleon Scattering
V. A. Okorokov
2015-01-01
Full Text Available The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on all the available experimental data at low and intermediate momentum transfer values. Energy dependence of the elastic diffraction slope is approximated by various analytic functions. The expanded “standard” logarithmic approximations with minimum number of free parameters allow description of the experimental slopes in all the available energy range reasonably. The estimations of asymptotic shrinkage parameter αP′ are obtained for various |t| domains based on all the available experimental data. Various approximations differ from each other both in the low energy and very high energy domains. Predictions for diffraction slope parameter are obtained for elastic proton-proton scattering from NICA up to future collider (FCC/VLHC energies, for proton-antiproton elastic reaction in FAIR energy domain for various approximation functions.
Modelling the Electro-Optic Properties of Liquid Crystals.
MacGregor, Alastair R.
Available from UMI in association with The British Library. Requires signed TDF. Liquid crystals (LCs) have been recognised as a phase of matter intermediate between solid and liquid for about 100 years. During this time a large variety of mesophases have been discovered but it is only recently that their physics have begun to be understood. However if LCs are to continue to compete successfully in the displays market an improved understanding of their electro-optic properties must be gained. This thesis describes work carried out on two different types of LC: nematic and ferroelectric chiral smectic C (SmC^{*} ). In the former the molecules are orientationally ordered and randomly positioned while in the latter they are orientationally ordered and arranged in layers. The local mean molecular orientation is called the director and defines the uniaxial optic axis in both types of LC. In a nematic guest-host (NGH) LC an anisotropically absorbing dye is dissolved in the LC and the dye molecules align so that their maximum absorption axis is parallel to the director. When an electric field is applied to a cell containing NGHLC the molecules tend to rotate, because of their dielectric anisotropy, and alter the cell's transmittance. Previous attempts to model the change in optical transmittance with voltage have assumed that the LC and dye molecules are perfectly aligned with the director. In this work the disorder of the molecules about the director is taken into account and the overall agreement between theory and experiment is improved considerably. A method of calculating how the SmC^ {*} director configuration and layer orientation vary with voltage is presented. This method is tested by calculating the transmittance of a 7 mu m thick SmC^{* } LC cell for different azimuthal orientations of the cell between crossed polarisers. It is shown that the theoretical and measured orientations which give minimum transmittance are in good agreement. It is also shown that the
Wavelength Division Multiplexing Passive Optical Network modeling Using Optical System Simulator
Nahla Abdulrahman Hussain
2015-09-01
Full Text Available Due to the continuing demand for larger bandwidth, the optical transport becoming general in the access network. Using optical fiber technologies, the communications infrastructure becomes powerful, providing very high speeds to transfer a high capacity of data. Existing telecommunications infrastructures is currently widely used Passive Optical Network that apply Wavelength Division Multiplexing (WDM and is awaited to play an important role in the future Internet supporting a large diversity of services and next generation networks. This paper presents a design of WDM-PON network, the simulation and analysis of transmission parameters in the Optisystem 7.0 environment for bidirectional traffic. The simulation shows the behavior of optical fiber links when the signal passes through all the components such as optical fiber, splitters, multiplexers then find a good quality of signal in all receivers. The system performance is presented through various parameters such as BER analyzer and the Eye Diagram.
Evaluation of the energy dependence of a zinc oxide nanofilm X-ray detector
Valenca, C.P.V., E-mail: claudia.cpvv@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Silveira, M.A.L.; Macedo, M.A., E-mail: odecamm@gmail.com [Universidade Federal de Sergipe (UFSE), Sao Cristovao, SE (Brazil); Santos, L.A.P, E-mail: lasantos@scients.com.br [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)
2015-07-01
International organizations of human health and radiation protection have recommended certain care for using of the X-ray as a diagnosis tool to avoid any type of radiological accident or overdose to the patient. This can be done assessing the parameters of the X-ray equipment and there are various types of detectors available for that: ionizing chamber, electronic semiconductor devices, etc. These detectors must be calibrated so that they can be used for any energy range and such a procedure is correlated with what is called the energy dependence of the detector. In accordance with the stated requirements of IEC 61267, the standard radiation quality beams and irradiation conditions (RQRs) are the tools and techniques for calibrating diagnostic X-Ray instruments and detectors. The purpose of this work is to evaluate the behavior of the energy dependence of a detector fabricated from a zinc oxide (ZnO) nanofilm. A Pantak industrial X-ray equipment was used to generate the RQR radiation quality beams and test three ZnO detector samples. A 6430 sub-femto-ammeter, Keithley, was used to bias the ZnO detector and simultaneously perform the output readings. The results showed that the ZnO device has some increase in its sensitivity to the ionizing radiation as the X-ray effective energy decreases unlike other types of semiconductor electronic devices typically used as an X-ray detector. We can conclude that the ZnO device can be used as a diagnostic X-ray detector with an appropriate calibration. (author)
Energy dependence of multiplicity fluctuations in heavy ion collisions at 20A to 158A GeV
Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chung, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Gazdzicki, M; Genchev, V; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kikola, D; Kliemant, M; Kniege, S; Kolesnikov, V I; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Laszlo, A; Lacey, R; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Peryt, W; Pikna, M; Pluta, J; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Slodkowski, M; Stefanek, G; Stock, R; Strabel, C; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Szuba, M; Szymanski, P; Trubnikov, V; Utvic, M; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Wojtaszek, A; Yoo, I K; Zimányi, J
2008-01-01
Multiplicity fluctuations of positively, negatively and all charged hadrons in the forward hemisphere were studied in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV. The multiplicity distributions and their scaled variances $\\omega$ are presented in dependence of collision energy as well as of rapidity and transverse momentum. The distributions have bell-like shape and their scaled variances are in the range from 0.8 to 1.2 without any significant structure in their energy dependence. No indication of the critical point fluctuations are observed. The string-hadronic model UrQMD significantly overpredicts the mean, but approximately reproduces the scaled variance of the multiplicity distributions. The predictions of the statistical hadron-resonance gas model obtained within the grand-canonical and canonical ensembles disagree with the measured scaled variances. The narrower than Poissonian multiplicity fluctuations measured in numerous cases may be explained by the impact of conservation laws on f...
Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chung, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Gazdzicki, M; Genchev, V; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kikola, D; Kliemant, M; Kniege, S; Kolesnikov, V I; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Laszlo, A; Lacey, R; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Peryt, W; Pikna, M; Pluta, J; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Slodkowski, M; Stefanek, G; Stock, R; Strabel, C; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Szuba, M; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Wojtaszek, A; Yoo, I K; Zimányi, J
2007-01-01
Results from electric charge correlations studied with the Balance Function method in A+A collisions from 20\\emph{A} to 158\\emph{A} GeV are presented in two different rapidity intervals: In the mid-rapidity region we observe a decrease of the width of the Balance Function distribution with increasing centrality of the collision, whereas this effect vanishes in the forward rapidity region. Results from the energy dependence study in central Pb+Pb collisions show that the narrowing of the Balance Function expressed by the normalised width parameter \\textit{W} increases with energy towards the highest SPS and RHIC energies. Finally we compare our experimental data points with predictions of several models. The hadronic string models UrQMD and HIJING do not reproduce the observed narrowing of the Balance Function. However, AMPT which contains a quark-parton transport phase before hadronization can reproduce the narrowing of the BF's width with centrality. This confirms the proposed sensitivity of the Balance Func...
Design-oriented analytic model of phase and frequency modulated optical links
Monsurrò, Pietro; Saitto, Antonio; Tommasino, Pasquale; Trifiletti, Alessandro; Vannucci, Antonello; Cimmino, Rosario F.
2016-07-01
An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare performance of the different architectures in terms of linearity and SFDR.
Modeling the reverberation of optical polarization in AGN
Rojas Lobos, P. A.; Goosmann, R.; Marin, F.
2016-12-01
According to the standard paradigm, the strong and compact luminosity of active galactic nuclei (AGN) is due to multi-temperature black body emission originating from an accretion disk formed around a supermassive black hole. This central engine is thought to be surrounded by a dusty region along the equatorial plane and by ionized winds along the poles. The innermost regions cannot yet be resolved neither in the optical nor in the infrared and it is fair to say that we still lack a satisfactory understanding of the physical processes, geometry and composition of the central (sub-parsec) components of AGN. Like spectral or polarimetric observations, the reverberation data needs to be modeled in order to infer constraints on the AGN geometry (such as the inner radius or the half-opening angle of the dusty torus). In this research note, we present preliminary modeling results using a time-dependent Monte Carlo method to solve the radiative transfer in a simplified AGN set up. We investigate different model configurations using both polarization and time lags and find a high dependency on the geometry to the time-lag response. For all models there is a clear distinction between edge-on or face-on viewing angles for fluxes and time lags, the later showing a higher wavelength-dependence than the former. Time lags, polarization and fluxes point toward a clear dichotomy between the different inclinations of AGN, a method that could help us to determine the true orientation of the nucleus in Seyfert galaxies.
Optical character recognition of handwritten Arabic using hidden Markov models
Aulama, Mohannad M. [University of Jordan; Natsheh, Asem M. [University of Jordan; Abandah, Gheith A. [University of Jordan; Olama, Mohammed M [ORNL
2011-01-01
The problem of optical character recognition (OCR) of handwritten Arabic has not received a satisfactory solution yet. In this paper, an Arabic OCR algorithm is developed based on Hidden Markov Models (HMMs) combined with the Viterbi algorithm, which results in an improved and more robust recognition of characters at the sub-word level. Integrating the HMMs represents another step of the overall OCR trends being currently researched in the literature. The proposed approach exploits the structure of characters in the Arabic language in addition to their extracted features to achieve improved recognition rates. Useful statistical information of the Arabic language is initially extracted and then used to estimate the probabilistic parameters of the mathematical HMM. A new custom implementation of the HMM is developed in this study, where the transition matrix is built based on the collected large corpus, and the emission matrix is built based on the results obtained via the extracted character features. The recognition process is triggered using the Viterbi algorithm which employs the most probable sequence of sub-words. The model was implemented to recognize the sub-word unit of Arabic text raising the recognition rate from being linked to the worst recognition rate for any character to the overall structure of the Arabic language. Numerical results show that there is a potentially large recognition improvement by using the proposed algorithms.
Optical character recognition of handwritten Arabic using hidden Markov models
Aulama, Mohannad M.; Natsheh, Asem M.; Abandah, Gheith A.; Olama, Mohammed M.
2011-04-01
The problem of optical character recognition (OCR) of handwritten Arabic has not received a satisfactory solution yet. In this paper, an Arabic OCR algorithm is developed based on Hidden Markov Models (HMMs) combined with the Viterbi algorithm, which results in an improved and more robust recognition of characters at the sub-word level. Integrating the HMMs represents another step of the overall OCR trends being currently researched in the literature. The proposed approach exploits the structure of characters in the Arabic language in addition to their extracted features to achieve improved recognition rates. Useful statistical information of the Arabic language is initially extracted and then used to estimate the probabilistic parameters of the mathematical HMM. A new custom implementation of the HMM is developed in this study, where the transition matrix is built based on the collected large corpus, and the emission matrix is built based on the results obtained via the extracted character features. The recognition process is triggered using the Viterbi algorithm which employs the most probable sequence of sub-words. The model was implemented to recognize the sub-word unit of Arabic text raising the recognition rate from being linked to the worst recognition rate for any character to the overall structure of the Arabic language. Numerical results show that there is a potentially large recognition improvement by using the proposed algorithms.
Accurate mask model implementation in optical proximity correction model for 14-nm nodes and beyond
Zine El Abidine, Nacer; Sundermann, Frank; Yesilada, Emek; Farys, Vincent; Huguennet, Frederic; Armeanu, Ana-Maria; Bork, Ingo; Chomat, Michael; Buck, Peter; Schanen, Isabelle
2016-04-01
In a previous work, we demonstrated that the current optical proximity correction model assuming the mask pattern to be analogous to the designed data is no longer valid. An extreme case of line-end shortening shows a gap up to 10 nm difference (at mask level). For that reason, an accurate mask model has been calibrated for a 14-nm logic gate level. A model with a total RMS of 1.38 nm at mask level was obtained. Two-dimensional structures, such as line-end shortening and corner rounding, were well predicted using scanning electron microscopy pictures overlaid with simulated contours. The first part of this paper is dedicated to the implementation of our improved model in current flow. The improved model consists of a mask model capturing mask process and writing effects, and a standard optical and resist model addressing the litho exposure and development effects at wafer level. The second part will focus on results from the comparison of the two models, the new and the regular.
Bogoni, Antonella; Potì, Luca; Ponzini, Filippo; Ghelfi, Paolo
2006-01-01
The electrical modeling of complex electrooptical devices is a useful task for the correct design of its schemes and for the estimation of its performance. In this paper, we consider an electrooptical phase-locked loop (PLL) used to synchronize an RF system clock to the repetition rate of an optical pulsed source, realized by an active fiber mode-locking (ML) technique in the regenerative configuration. The synchronization scheme is suggested by a description of the pulsed source, for the first time, as an optical voltage-control oscillator (VCO). In particular, we present a simple new all-electrical model for the proposed optical VCO, and we verify its accuracy by the implementation of the whole PLL scheme at 2.5 and 10 GHz.
Optical Network Models and Their Application to Software-Defined Network Management
Thomas Szyrkowiec
2017-01-01
Full Text Available Software-defined networking is finding its way into optical networks. Here, it promises a simplification and unification of network management for optical networks allowing automation of operational tasks despite the highly diverse and vendor-specific commercial systems and the complexity and analog nature of optical transmission. Common abstractions and interfaces are a fundamental component for software-defined optical networking. Currently, a number of models for optical networks are available. They all claim to provide open and vendor agnostic management of optical equipment. In this work, we survey and compare the most important models and propose an intent interface for creating virtual topologies which is integrated in the existing model ecosystem.
Feng, Ying; Zeng, Xin; Li, Wei-hua; Wang, Wen-cong; Ou-Yang, Li-si; Sun, Xi; Lv, Zhiyue; Wu, Zhong-Dao
2014-11-01
Human Angiostrongylus cantonensis (A. cantonensis) is a food-borne parasitic disease and can cause optic neuritis. Increasing clinical angiostrongyliasis cases with optic neuritis have been reported, but the pathogenesis has not been fully understood until now. Here, we applied rats with A. cantonensis infection as an animal model to study the pathogenesis of optic neuritis caused by the infection. We observed that the optic disk of experimental rats appeared hyperemic, the retina vein became thick, and the visual evoked potential (VEP) latency was prolonged. There were obvious inflammatory cell infiltration in the retina and optic nerve adventitia followed with obvious optic nerve fiber demyelination and retina ganglion swelling. We also evaluated the effect of dexamethasone combined with albendazole on optic neuritis of rats infected with A. cantonensis. The results showed it had no obvious effect to prevent progressive visual deterioration for optic neuritis caused by A. cantonensis. The studies provided evidence that the pathogenesis of optic neuritis in infected rats was correlated to optic nerve demyelination and ganglion cell damage caused by optic nerve inflammation, and the common therapy to this disease was not so effective. Based on the above results, it may be necessary to combine neuroprotective agents with common therapy to treat and protect optic nerve and ganglion cells from their secondary injury.
Modeling of coherent ultrafast magneto-optical experiments: Light-induced molecular mean-field model
Hinschberger, Y. [Instituto de Física dos Materiais da Universidade do Porto, Departamento de Física et Astronomia, Rua do campo Alegre, 687, 4169-007 Porto (Portugal); Hervieux, P.-A. [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504 BP 43 - F-67034 Strasbourg Cedex 2 (France)
2015-12-28
We present calculations which aim to describe coherent ultrafast magneto-optical effects observed in time-resolved pump-probe experiments. Our approach is based on a nonlinear semi-classical Drude-Voigt model and is used to interpret experiments performed on nickel ferromagnetic thin film. Within this framework, a phenomenological light-induced coherent molecular mean-field depending on the polarizations of the pump and probe pulses is proposed whose microscopic origin is related to a spin-orbit coupling involving the electron spins of the material sample and the electric field of the laser pulses. Theoretical predictions are compared to available experimental data. The model successfully reproduces the observed experimental trends and gives meaningful insight into the understanding of magneto-optical rotation behavior in the ultrafast regime. Theoretical predictions for further experimental studies are also proposed.
The Dynamics of Semiconductor Optical Amplifiers – Modeling and Applications
Mørk, Jesper; Nielsen, Mads Lønstrup; Berg, Tommy Winther
2003-01-01
The importance of semiconductor optical amplifiers is discussed. A semiconductor optical amplifier (SOA) is a semiconductor laser with anti-reflection coated facets that amplifies an injected light signal by means of stimulated emission. SOAs have a number of unique properties that open up...
General Theoretical Model for Resonantly Enhanced Optical Modulators
Yuvaraja; S.; Visagathilagar; Arnan; Mitchell; Michael; W.; Austin
2003-01-01
1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow bandwidth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandwidth.
Analytic Models for Radiation Induced Loss in Optical Fibers II. A Physical Model,
1984-06-01
and identify by Mock number) PIEL GRUP UB.GR. Optical fibers Analytical models Radiation effects 19. ABSTRACT (ConinueII. anl mwr,f fneciua,, and...conditions specified in the derivation of the equations existed during the irradiations. This is because the functional form of the equations is not...tion is not necessarily incorrect. If one assumes a relatively simple form of re- covery as a function of time, such as an exponential recovery, it can
Modelling Thermoelastic Distortion of Optics Using Elastodynamic Reciprocity
King, Eleanor; Veitch, Peter; Levin, Yuri
2015-01-01
Thermoelastic distortion resulting from optical absorption by transmissive and reflective optics can cause unacceptable changes in optical systems that employ high power beams. In advanced-generation laser-interferometric gravitational wave detectors for example, optical absorption is expected to result in wavefront distortions that would compromise the sensitivity of the detector; thus necessitating the use of adaptive thermal compensation. Unfortunately, these systems have long thermal time constants and so predictive feed-forward control systems could be required - but the finite-element analysis is computationally expensive. We describe here the use of the Betti-Maxwell elastodynamic reciprocity theorem to calculate the response of linear elastic bodies (optics) to heating that has arbitrary spatial distribution. We demonstrate using a simple example, that it can yield accurate results in computational times that are significantly less than those required for finite-element analyses.
Multimodal nonlinear optical imaging of cartilage development in mouse model
He, Sicong; Xue, Wenqian; Sun, Qiqi; Li, Xuesong; Huang, Jiandong; Qu, Jianan Y.
2017-02-01
Kinesin-1 is a kind of motor protein responsible for intracellular transportation and has been studied in a variety of tissues. However, its roles in cartilage development are not clear. In this study, a kinesin-1 heavy chain (Kif5b) knockout mouse model is used to study the functions of kinesin-1 in the cartilage development. We developed a multimodal nonlinear optical (NLO) microscope system integrating stimulated Raman scattering (SRS), second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) to investigate the morphological and biomedical characteristics of fresh tibial cartilage from normal and mutant mice at different developmental stages. The combined forward and backward SHG imaging resolved the fine structure of collagen fibrils in the extracellular matrix of cartilage. Meanwhile, the chondrocyte morphology in different zones of cartilage was visualized by label-free SRS and TPEF images. The results show that the fibrillar collagen in the superficial zone of cartilage in postnatal day 10 and 15 (P10 and P15) knockout mice was significantly less than that of control mice. Moreover, we observed distorted morphology and disorganization of columnar arrangement of chondrocytes in the growth plate cartilage of mutant mice. This study reveals the significant roles of kinesin-1 in collagen formation and chondrocyte morphogenesis.
Modelling of bio-optical parameters of open ocean waters
Vadim N. Pelevin
2001-12-01
Full Text Available An original method for estimating the concentration of chlorophyll pigments, absorption of yellow substance and absorption of suspended matter without pigments and yellow substance in detritus using spectral diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance data has been applied to sea waters of different types in the open ocean (case 1. Using the effective numerical single parameter classification with the water type optical index m as a parameter over the whole range of the open ocean waters, the calculations have been carried out and the light absorption spectra of sea waters tabulated. These spectra are used to optimize the absorption models and thus to estimate the concentrations of the main admixtures in sea water. The value of m can be determined from direct measurements of the downward irradiance attenuation coefficient at 500 nm or calculated from remote sensing data using the regressions given in the article. The sea water composition can then be readily estimated from the tables given for any open ocean area if that one parameter m characterizing the basin is known.
Powell, Samuel; Arridge, Simon R.; Leung, Terence S.
2015-03-01
Ultrasound-modulated optical tomography is an emerging biomedical imaging modality which uses the spatially localised acoustically-driven modulation of coherent light as a probe of the structure and optical properties of biological tissues. In this work we model the first-harmonic flux generated by the coupled physics using a simple linearised diffusion-style forward model. We derive analytical expressions for the sensitivity of this measurement type with respect to the optical absorption and scattering coefficients. These correlation measurement density functions can be employed as part of an image-reconstruction procedure capable of reconstructing quantitative images of the optical properties of a medium under investigation.
A traffic model of optical networks based on time-space complexity and traffic grooming
Zhao Yongli; Zhang Jie; Han Dahai; Wang Lei; Chen Xiuzhong; Gu Wanyi
2009-01-01
This paper researched the traffic of optical networks in time-space complexity, proposed a novel traffic model for complex optical networks based on traffic grooming, designed a traffic generator GTS (generator based on time and space) with "centralized + distributed" idea, and then made a simulation in C language. Experiments results show that GTS can produce the virtual network topology which can change dynamically with the characteristic of scaling-free network. GTS can also groom the different traffic and trigger them under real-time or scheduling mechanisms, generating different optical connections. This traffic model is convenient for the simulation of optical networks considering the traffic complexity.
Energy-dependent expansion of .177 caliber hollow-point air gun projectiles.
Werner, Ronald; Schultz, Benno; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias
2017-05-01
Amongst hundreds of different projectiles for air guns available on the market, hollow-point air gun pellets are of special interest. These pellets are characterized by a tip or a hollowed-out shape in their tip which, when fired, makes the projectiles expand to an increased diameter upon entering the target medium. This results in an increase in release of energy which, in turn, has the potential to cause more serious injuries than non-hollow-point projectiles. To the best of the authors' knowledge, reliable data on the terminal ballistic features of hollow-point air gun projectiles compared to standard diabolo pellets have not yet been published in the forensic literature. The terminal ballistic performance (energy-dependent expansion and penetration) of four different types of .177 caliber hollow-point pellets discharged at kinetic energy levels from approximately 3 J up to 30 J into water, ordnance gelatin, and ordnance gelatin covered with natural chamois as a skin simulant was the subject of this investigation. Energy-dependent expansion of the tested hollow-point pellets was observed after being shot into all investigated target media. While some hollow-point pellets require a minimum kinetic energy of approximately 10 J for sufficient expansion, there are also hollow-point pellets which expand at kinetic energy levels of less than 5 J. The ratio of expansion (RE, calculated by the cross-sectional area (A) after impact divided by the cross-sectional area (A 0) of the undeformed pellet) of hollow-point air gun pellets reached values up of to 2.2. The extent of expansion relates to the kinetic energy of the projectile with a peak for pellet expansion at the 15 to 20 J range. To conclude, this work demonstrates that the hollow-point principle, i.e., the design-related enlargement of the projectiles' frontal area upon impact into a medium, does work in air guns as claimed by the manufacturers.
A model of the mammalian optic nerve fibre based on experimental data.
Oozeer, M; Veraart, C; Legat, V; Delbeke, J
2006-08-01
Several experimental data about membrane dynamics and pharmacological sensitivities of optic nerve axons have been published. The present work summarizes these data and computer simulations have been used to develop a model of the mammalian optic nerve fibre. The ionic currents description were derived from existing membrane models and particularly from a model of the somatic retinal ganglion cell (RGC) impulse generation. However, original equations had to be modified to match experimental data, which suggests that in RGCs, axonal and somatic ion channel expression are different. The new model is consistent with recent experimental results about optic nerve axonal excitability.
Dabirian, Ali
2017-02-15
High-efficiency crystalline silicon (c-Si) solar cells increasingly feature sophisticated electron and hole contacts aimed at minimizing electronic losses. At the rear of photovoltaic devices, such contacts—usually consisting of stacks of functional layers—offer opportunities to enhance the infrared response of the solar cells. Here, we propose an accurate and simple modeling procedure to evaluate the infrared performance of rear contacts in c-Si solar cells. Our method combines full-wave electromagnetic modeling of the rear contact with a statistical ray optics model to obtain the fraction of optical energy dissipated from the rear contact relative to that absorbed by the Si wafer. Using this technique, we study the impact of the refractive index, extinction coefficient, and thickness of the rear-passivating layer and establish basic design rules. In addition, we evaluate novel optical structures, including stratified thin films, nanoparticle composites, and conductive nanowires embedded in a low-index dielectric matrix, for integration into advanced rear contacts in c-Si photovoltaic devices. From an optical perspective, nanowire structures preserving low contact resistance appear to be the most effective approach to mitigating dissipation losses from the rear contact.
Visual Evoked Potential Recording in a Rat Model of Experimental Optic Nerve Demyelination.
You, Yuyi; Gupta, Vivek K; Chitranshi, Nitin; Reedman, Brittany; Klistorner, Alexander; Graham, Stuart L
2015-07-29
The visual evoked potential (VEP) recording is widely used in clinical practice to assess the severity of optic neuritis in its acute phase, and to monitor the disease course in the follow-up period. Changes in the VEP parameters closely correlate with pathological damage in the optic nerve. This protocol provides a detailed description about the rodent model of optic nerve microinjection, in which a partial demyelination lesion is produced in the optic nerve. VEP recording techniques are also discussed. Using skull implanted electrodes, we are able to acquire reproducible intra-session and between-session VEP traces. VEPs can be recorded on individual animals over a period of time to assess the functional changes in the optic nerve longitudinally. The optic nerve demyelination model, in conjunction with the VEP recording protocol, provides a tool to investigate the disease processes associated with demyelination and remyelination, and can potentially be employed to evaluate the effects of new remyelinating drugs or neuroprotective therapies.
Eng, Ron; Arnold, William R.; Baker, Markus A.; Bevan, Ryan M.; Burdick, Gregory; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Hanson, Craig; Hogue, William D.; Kegley, Jeffrey R.; Kirk, Charlie; Maffett, Steven P.; Matthews, Gary W.; Siler, Richard D.; Smith, W. Scott; Stahl, H. Philip; Tucker, John M.; Wright, Ernest R.
2013-09-01
A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE® mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.
Eng, Ron; Arnold, William R.; Baker, Marcus A.; Bevan, Ryan M.; Burdick, Gregory; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Hanson, Craig; Hogue, William D.; Kegley, Jeffrey R.; Kirk, Charlie; Maffett, Steven P.; Matthews, Gary W.; Siler, Richard D.; Smith, W. Scott; Stahl, H. Philip; Tucker, John M.; Wright, Ernest R.
2013-01-01
A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE® mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.
Eng, Ron; Arnold, William; Baker, Markus A.; Bevan, Ryan M.; Carpenter, James R.; Effinger, Michael R.; Gaddy, Darrell E.; Goode, Brian K.; Kegley, Jeffrey R.; Hogue, William D.; Siler, Richard D.; Smith, W. Scott; Stahl. H. Philip; Tucker, John M.; Wright, Ernest R.; Kirk, Charles S.; Hanson, Craig; Burdick, Gregory; Maffett, Steven
2013-01-01
A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.
Modeling and model-aware signal processing methods for enhancement of optical systems
Aksoylar, Aydan
Theoretical and numerical modeling of optical systems are increasingly being utilized in a wide range of areas in physics and engineering for characterizing and improving existing systems or developing new methods. This dissertation focuses on determining and improving the performance of imaging and non-imaging optical systems through modeling and developing model-aware enhancement methods. We evaluate the performance, demonstrate enhancements in terms of resolution and light collection efficiency, and improve the capabilities of the systems through changes to the system design and through post-processing techniques. We consider application areas in integrated circuit (IC) imaging for fault analysis and malicious circuitry detection, and free-form lens design for creating prescribed illumination patterns. The first part of this dissertation focuses on sub-surface imaging of ICs for fault analysis using a solid immersion lens (SIL) microscope. We first derive the Green's function of the microscope and use it to determine its resolution limits for bulk silicon and silicon-on-insulator (SOI) chips. We then propose an optimization framework for designing super-resolving apodization masks that utilizes the developed model and demonstrate the trade-offs in designing such masks. Finally, we derive the full electromagnetic model of the SIL microscope that models the image of an arbitrary sub-surface structure. With the rapidly shrinking dimensions of ICs, we are increasingly limited in resolving the features and identifying potential modifications despite the resolution improvements provided by the state-of-the-art microscopy techniques and enhancement methods described here. In the second part of this dissertation, we shift our focus away from improving the resolution and consider an optical framework that does not require high resolution imaging for detecting malicious circuitry. We develop a classification-based high-throughput gate identification method that utilizes
Zhu, Guangzhi; Qiu, Yuli; Wang, Zexiong; Zhu, Xiao; Zhu, Changhong
2016-08-01
An analytical model is developed to analyze the optical field distribution of thin disk laser with a thermal-optical aberration gain medium. The fundamental mode field distribution is calculated by using the eigenvector method of the resonator transit matrix for different pumping parameters. The analytical results show that the uniformity of the pumping spot is an important factor that impacts the beam quality of thin disk laser. The uniform pumping spot is beneficial to decrease thermal aberration and Optical Path Difference (OPD) of thin disk crystal, and to improve the beam quality. However, the beam quality still decreases slightly with the increasing of pumping intensity under the uniform pumping condition. The main reason for degradation of beam quality is the aspherical part of OPD which leads to diffraction losses of the resonator and wavefront deformation.
Holzlöhner, R.; Taubenberger, S.; Rakich, A. P.; Noethe, L.; Schipani, P.; Kuijken, K.
2016-08-01
We study a novel focal plane wavefront sensing and active optics control scheme at the VST on Cerro Paranal, an f/5.5 survey telescope with a 1x1 degree field of view and a 2.6m primary mirror. This scheme analyzes the elongation pattern of stellar PSFs across the full science image (256 Mpixels) and compares their second moments with an analytical model based on 5th-order geometrical optics. We consider 11 scalar degrees of freedom in mirror misalignments and deformations (M2 piston, tip/tilt and lateral displacement, detector tip/tilt, plus M1 figure astigmatism and trefoil). Using a numerical optimization method, we extract up to 4000 stars and complete the fitting process in under one minute. We demonstrate successful closed-loop active optics control based on maximum likelihood filtering.
Energy Dependent Divisible Load Theory for Wireless Sensor Network Workload Allocation
Haiyan Shi
2012-01-01
Full Text Available The wireless sensor network (WSN, consisting of a large number of microsensors with wireless communication abilities, has become an indispensable tool for use in monitoring and surveillance applications. Despite its advantages in deployment flexibility and fault tolerance, the WSN is vulnerable to failures due to the depletion of limited onboard battery energy. A major portion of energy consumption is caused by the transmission of sensed results to the master processor. The amount of energy used, in fact, is related to both the duration of sensing and data transmission. Hence, in order to extend the operation lifespan of the WSN, a proper allocation of sensing workload among the sensors is necessary. An assignment scheme is here formulated on the basis of the divisible load theory, namely, the energy dependent divisible load theory (EDDLT for sensing workload allocations. In particular, the amount of residual energies onboard sensors are considered while deciding the workload assigned to each sensor. Sensors with smaller amount of residual energy are assigned lighter workloads, thus, allowing for a reduced energy consumption and the sensor lifespan is extended. Simulation studies are conducted and results have illustrated the effectiveness of the proposed workload allocation method.
Global, Energy-Dependent Ring Current Response During Two Large Storms
Goldstein, J.; Angelopoulos, V.; Burch, J. L.; De Pascuale, S.; Fuselier, S. A.; Genestreti, K. J.; Kurth, W. S.; LLera, K.; McComas, D. J.; Reeves, G. D.; Spence, H. E.; Valek, P. W.
2015-12-01
Two recent large (~200 nT) geomagnetic storms occurred during 17--18 March 2015 and 22--23 June 2015. The global, energy-dependent ring current response to these two extreme events is investigated using both global imaging and multi-point in situ observations. Energetic neutral atom (ENA) imaging by the Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a global view of ring current ions. Local measurements are provided by two multi-spacecraft missions. The two Van Allen Probes measure in situ plasma (including ion composition) and fields at ring current and plasmaspheric L values. The recently launched Magnetospheric Multiscale (MMS) comprises four spacecraft that have just begun to measure particles (including ion composition) and fields at outer magnetospheric L-values. We analyze the timing and energetics of the stormtime evolution of ring current ions, both trapped and precipitating, using TWINS ENA images and in situ data by the Van Allen Probes and MMS.
Investigation of the energy dependence of the orbital light curve in LS 5039
Chang, Z; Ji, L; Chen, Y P; Kretschmar, P; Kuulkers, E; Collmar, W; Liu, C Z
2016-01-01
LS 5039 is so far the best studied $\\gamma$-ray binary system at multi-wavelength energies. A time resolved study of its spectral energy distribution (SED) shows that above 1 keV its power output is changing along its binary orbit as well as being a function of energy. To disentangle the energy dependence of the power output as a function of orbital phase, we investigated in detail the orbital light curves as derived with different telescopes at different energy bands. We analysed the data from all existing \\textit{INTEGRAL}/IBIS/ISGRI observations of the source and generated the most up-to-date orbital light curves at hard X-ray energies. In the $\\gamma$-ray band, we carried out orbital phase-resolved analysis of \\textit{Fermi}-LAT data between 30 MeV and 10 GeV in 5 different energy bands. We found that, at $\\lesssim$100 MeV and $\\gtrsim$1 TeV the peak of the $\\gamma$-ray emission is near orbital phase 0.7, while between $\\sim$100 MeV and $\\sim$1 GeV it moves close to orbital phase 1.0 in an orbital anti-cl...
Dun-Hai LI; Lan-Zhou CHEN; Gen-Bao LI; Gao-Hong WANG; Li-Rong SONG; Yong-Ding LIU
2005-01-01
Hormogonium, which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats, is a distinguishable developmental stage of heterocystous cyanobacteria. The present study examined the effects of different light conditions and sugars on the of hormogonia was light dependent in the absence of sugar, but that close to 100% of cyanobacteria differentiated to hormogonia in the presence of glucose or sucrose, irrespective of the light conditions. This differentiation was inhibited, even in the presence of sugars, upon application of an inhibitor of respiration.Following the testing of different sugars, the effects of different lights were examined. It was found that 5-10 μmol.m-2.s-1 photon flux density was optimal for hormogonia differentiation. One hundred percent differentiation was obtained with white light irradiation, in contrast with irradiation with green light (80%differentiation) and red light (0-10% differentiation). Although they showed different efficiencies in induc ing hormogonia differentiation in N. sphaeroides, the green and red radiation did not display antagonistic effects. When the additional aspect of time dependence was investigated through the application of different light radiations and an inhibitor of protein synthesis, it was found that the initial 6 h of the differentiation process was crucial for hormogonia differentiation. Taken together, these results show that hormogonia differentiation in N. sphaeroides is either a photoregulated or an energy dependent process.
Subpicosecond Photon-Energy-Dependent Hole Transfer from PbS Quantum Dots to Conjugated Polymers.
Colbert, Adam E; Jedlicka, Erin; Wu, Wenbi; Ginger, David S
2016-12-15
We use transient absorption (TA) spectroscopy to study the origin of photon-energy dependent hole transfer yields in blends of PbS quantum dots with the conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT). We selectively excite only the quantum dots at two different wavelengths and measure the polymer ground state bleach resulting from the transfer of photoexcited holes. The higher photon-energy pump shows a greater prompt yield of hole transfer compared to the lower photon-energy excitation, on time scales sufficient to out-compete hot carrier cooling in lead chalcogenide quantum dots. We interpret the results as evidence that the excess energy of nonthermalized, or "hot," excitons resulting from higher photon-energy excitation allows more efficient charge transfer to the polymer in these systems. The data also demonstrate slow charge transfer rates, up to ∼1 ns, of the relaxed excitations on the PbS dots. These findings help to clarify the role of excess photon energy and carrier relaxation dynamics on free carrier generation in donor/acceptor solar cells.
Helium-3 Microscopic Optical Model Potential Based on Skyrme Interaction
2008-01-01
<正>The helium-3 microscopic optical potential is obtained by Green function method through nuclear matter approximation and local density approximation based on the effective Skyrme interaction. The reaction cross
Liu Yu-Min; Yu Zhong-Yuan
2009-01-01
Calculations of electronic structures about the semiconductor quantum dot and the semiconductor quantum ring are presented in this paper. To reduce the calculation costs, for the quantum dot and the quantum ring, their simplified axially symmetric shapes are utilized in our analysis. The energy dependent effective mass is taken into account in solving the Schrodinger equations in the single band effective mass approximation. The calculated results show that the energy dependent effective mass should be considered only for relatively small volume quantum dots or small quantum rings. For large size quantum materials, both the energy dependent effective mass and the parabolic effective mass can give the same results. The energy states and the effective masses of the quantum dot and the quantum ring as a function of geometric parameters are also discussed in detail.
A. Chandrasekhar Reddy; Jatin Rathod; Girija Rajaram; Radharani Alyana; D. S. Misra; C. G. Patil; M. Y. S. Prasad; A. G. Ananth
2008-03-01
In view of the renewed interest in the study of energetic particles in the outer radiation belt of the earth, we feel it will be helpful in looking for the energy dependence of the electron energy spectrum at geostationary orbit. This may give us some insight into how we can safeguard geostationary satellites from functional anomalies of the deep dielectric charging type, which are caused by charge accumulation and subsequent discharge of relativistic electrons. In this study we examine whether there is any energy dependence in relativistic electron enhancements at geosynchronous altitudes during solar energetic proton events of 2005.
A General Epipolar-Line Model between Optical and SAR Images and Used in Image Matching
Shuai Xing
2014-02-01
Full Text Available The search space and strategy are important for optical and SAR image matching. In this paper a general epipolar-line model has been proposed between linear array push-broom optical and SAR images. Then a dynamic approximate epipolar-line constraint model (DAELCM has been constructed and used to construct a new image matching algorithm with Harris operator and CRA. Experimental results have shown that the general epipolar-line model is valid and successfully used in optical and SAR image matching, and effectively limits the search space and decreased computation.
Problems of large neurodynamics system modeling: optical synergetics and neural networks
Vorontsov, Mikhail A.
1991-04-01
The possibilities of modeling developed neuronetwork dynamics are investigated by nonlinear coherent optical systems with a 2-D feedback. A comparative analysis of neuron-like systems of various physical nature has been made. The results of experimental investigations of nonlinear optical system dynamics with nonlocal connections are discussed.
Modelling of optically stimulated luminescence of zircon : assessment of the suitability for dating
Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den
2006-01-01
The mineral zircon, ZrSiO4, is a candidate material for optical dating because it exhibits luminescence after exposure to natural radioactivity. The kinetic model of zircon thermally stimulated luminescence proposed before has been modified and used to investigate optically Stimulated luminescence (
Modeling of semiconductor devices for high-speed all-optical signal processing
Bischoff, Svend; Højfeldt, Sune; Mørk, Jesper
2001-01-01
The all-optical signal processing performance of devices based on active semiconductor waveguides is investigated. A large signal model is used to analyse the physical mechanisms limiting the high-speed performance of both semiconductor optical amplifiers (SOAs) and electro-absorption modulators ...
S. Dutkiewicz
2015-07-01
This new model that captures bio-optical feedbacks will be important for improving our understanding of the role of light and optical constituents on ocean biogeochemistry, especially in a changing environment. Further, resolving surface upwelling irradiance will make it easier to connect to satellite-derived products in the future.
Modelling of the Optical Detector System in a Compact Disc Player
Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle;
2003-01-01
The cross-couplings between focus and radial tracking servos in compact disc players are important, but the optical cross couplings are not well described in the literature. In this paper an optical model of a compact disc player based on the three beam single foucault detector principle is found......, which includes the cross couplings between focus and radial loops....
Modeling the video distribution link in the Next Generation Optical Access Networks
Amaya, F.; Cárdenas, A.; Tafur Monroy, Idelfonso
2011-01-01
In this work we present a model for the design and optimization of the video distribution link in the next generation optical access network. We analyze the video distribution performance in a SCM-WDM link, including the noise, the distortion and the fiber optic nonlinearities. Additionally, we...
Lin, Alex W H; Lewinski, Nastassja A; West, Jennifer L; Halas, Naomi J; Drezek, Rebekah A
2005-01-01
Many optical diagnostic approaches rely on changes in scattering and absorption properties to generate optical contrast between normal and diseased tissue. Recently, there has been increasing interest in using exogenous agents to enhance this intrinsic contrast with particular emphasis on the development for targeting specific molecular features of disease. Gold nanoshells are a class of core-shell nanoparticles with an extremely tunable peak optical resonance ranging from the near-UV to the mid-IR wavelengths. Using current chemistries, nanoshells of a wide variety of core and shell sizes can easily be fabricated to scatter and/or absorb light with optical cross sections often several times larger than the geometric cross section. Using gold nanoshells of different size and optical parameters, we employ Monte Carlo models to predict the effect of varying concentrations of nanoshells on tissue reflectance. The models demonstrate the importance of absorption from the nanoshells on remitted signals even when the optical extinction is dominated by scattering. Furthermore, because of the strong optical response of nanoshells, a considerable change in reflectance is observed with only a very small concentration of nanoshells. Characterizing the optical behavior of gold nanoshells in tissue will aid in developing nanoshells as contrast agents for optical diagnostics.
Quantum simulation of correlated-hopping models with fermions in optical lattices
Liberto, M. Di; Creffield, C. E.; Japaridze, G. I.; Smith, C. Morais
2014-01-01
By using a modulated magnetic field in a Feshbach resonance for ultracold fermionic atoms in optical lattices, we show that it is possible to engineer a class of models usually referred to as correlated-hopping models. These models differ from the Hubbard model in exhibiting additional density-depen
Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems
Wu, Zhizheng; Ben Amara, Foued
2013-01-01
Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foue...
Full wave model of image formation in optical coherence tomography applicable to general samples.
Munro, Peter R T; Curatolo, Andrea; Sampson, David D
2015-02-09
We demonstrate a highly realistic model of optical coherence tomography, based on an existing model of coherent optical microscopes, which employs a full wave description of light. A defining feature of the model is the decoupling of the key functions of an optical coherence tomography system: sample illumination, light-sample interaction and the collection of light scattered by the sample. We show how such a model can be implemented using the finite-difference time-domain method to model light propagation in general samples. The model employs vectorial focussing theory to represent the optical system and, thus, incorporates general illumination beam types and detection optics. To demonstrate its versatility, we model image formation of a stratified medium, a numerical point-spread function phantom and a numerical phantom, based upon a physical three-dimensional structured phantom employed in our laboratory. We show that simulated images compare well with experimental images of a three-dimensional structured phantom. Such a model provides a powerful means to advance all aspects of optical coherence tomography imaging.
Experimental verification of optical models of graphene with multimode slab waveguides.
Chang, Zeshan; Chiang, Kin Seng
2016-05-01
We compare three optical models of graphene, namely, the interface model, the isotropic model, and the anisotropic model, and verify them experimentally with two multimode slab waveguide samples operating at the wavelengths of 632.8 and 1536 nm. By comparing the calculated graphene-induced losses and the measurement data, we confirm that the interface model and the anisotropic model give correct results for both the transverse electric (TE) and transverse magnetic modes, while the isotropic model gives correct results only for the TE modes. With the experimental data, we also quantitatively verify the widely used expression for the surface conductivity of graphene in the optical regime. Our findings clarify the issue of modeling graphene in the analysis of graphene-incorporated waveguides and offer deeper insight into the optical properties of graphene for waveguide applications.
Surface modeling for optical fabrication with linear ion source
Wu, Lixiang; Shao, Jianda
2016-01-01
We present a concept of surface decomposition extended from double Fourier series to nonnegative sinusoidal wave surfaces, on the basis of which linear ion sources apply to the ultra-precision fabrication of complex surfaces and diffractive optics. It is the first time that we have a surface descriptor for building a relationship between the fabrication process of optical surfaces and the surface characterization based on PSD analysis, which akin to Zernike polynomials used for mapping the relationship between surface errors and Seidel aberrations. Also, we demonstrate that the one-dimensional scanning of linear ion source is applicable to the removal of surface errors caused by small-tool polishing in raster scan mode as well as the fabrication of beam sampling grating of high diffractive uniformity without a post-processing procedure. The simulation results show that, in theory, optical fabrication with linear ion source is feasible and even of higher output efficiency compared with the conventional approac...
The value of adding optics to ecosystem models: a case study
M. Fujii
2007-10-01
Full Text Available Many ecosystem models have been developed to study the ocean's biogeochemical properties, but most of these models use simple formulations to describe light penetration and spectral quality. Here, an optical model is coupled with a previously published ecosystem model that explicitly represents two phytoplankton (picoplankton and diatoms and two zooplankton functional groups, as well as multiple nutrients and detritus. Surface ocean color fields and subsurface light fields are calculated by coupling the ecosystem model with an optical model that relates biogeochemical standing stocks with inherent optical properties (absorption, scattering; this provides input to a commercially available radiative transfer model (Ecolight. We apply this bio-optical model to the equatorial Pacific upwelling region, and find the model to be capable of reproducing many measured optical properties and key biogeochemical processes in this region. Our model results suggest that non-algal particles largely contribute to the total scattering or attenuation (>50% at 660 nm but have a much smaller contribution to particulate absorption (<20% at 440 nm, while picoplankton dominate the total phytoplankton absorption (>95% at 440 nm. These results are consistent with the field observations. In order to achieve such good agreement between data and model results, however, key model parameters, for which no field data are available, have to be constrained. Sensitivity analysis of the model results to optical parameters reveals a significant role played by colored dissolved organic matter through its influence on the quantity and quality of the ambient light. Coupling explicit optics to an ecosystem model provides advantages in generating: (1 a more accurate subsurface light-field, which is important for light sensitive biogeochemical processes such as photosynthesis and photo-oxidation, (2 additional constraints on model parameters that help to reduce uncertainties in
Bastos, Fernanda M.; Silva, Teogenes A. da, E-mail: fernanda_mbastos@yahoo.com.br, E-mail: silvata@cdtn.br [Centro de Desenvolvimeto da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)
2014-07-01
This work was with the main objective to study the energy dependence of extrapolation chamber in low energy X-rays to determine the value of the uncertainty associated with the variation of the incident radiation energy in the measures in which it is used. For studying the dependence of energy, were conducted comparative ionization current measurements between the extrapolation chamber and two ionization chambers: a chamber mammography, RC6M model, Radcal with energy dependence less than 5% and a 2575 model radioprotection chamber NE Technology; both chambers have very thin windows, allowing its application in low power beams. Measurements were made at four different depths of 1.0 to 4.0 mm extrapolation chamber, 1.0 mm interval, for each reference radiation. The study showed that there is a variable energy dependence on the volume of the extrapolation chamber. In other analysis, it is concluded that the energy dependence of extrapolation chamber becomes smaller when using the slope of the ionization current versus depth for the different radiation reference; this shows that the extrapolation technique, used for the absorbed dose calculation, reduces the uncertainty associated with the influence of the response variation with energy radiation.
Optical fiber communication systems with Matlab and Simulink models
Binh, Le Nguyen
2014-01-01
""This book adds an aspect of programming and simulation not so well developed in other books. It is complete in this sense and enables directly linking the physics of optical components and systems to realistic results.""-Martin Rochette, Associate Professor, McGill University, Quebec, Canada""…this will be an excellent textbook since it has all new development and information on optical communication systems…I think this book can easily replace many other textbooks in this field.""-Massoud Moussavi, California State Polytechnic University-Pomona""The book is well written. It describes the fu
Wei Bengang
2016-01-01
Full Text Available In this paper, the different types of discharge in transformer were simulated based on the real transformer fault model. The optical partial discharge detection system was established based on optical sensors which were capturing partial discharge accompanied by optical effects. In this research, surface discharge and suspended discharge defect model was pressurized to generate partial discharge signal. The results showed that: Partial discharge optical signals could effectively respond the production and development process of transformer partial discharge. It was able to assess discharge level also. When the discharge phenomenon stabilized, the phase of surface discharge mainly between 60°~150°and 240°~330°, the phase of suspended discharge mainly between 260°~320°. According to the phase characteristic of discharge pattern, the creeping discharge and suspended discharge phenomenon of transformer can be distinguished. It laid the foundation for the application of transformer optical partial discharge detection technology.
Jana Sajgalikova
2015-01-01
Full Text Available Mathematical models for description of physical phenomena often use the statistical description of the individual phenomena and solve those using suitable methods. If we want to develop numerical model of optical communication system based on transmission through single mode optical fibres, we need to consider whole series of phenomena that affect various parts of the system. In the single-mode optical fibre we often encounter influence of chromatic dispersion and nonlinear Kerr effects. By observing various different degradation mechanisms, every numerical model should have its own limits, which fulfil more detailed specification. It is inevitable to consider them in evaluation. In this paper, we focus on numerical modelling of degradation mechanisms in single-mode optical fibre. Numerical solution of non-linear Schroedinger equation is performed by finite difference method applied in MATLAB environment and split-step Fourier method, which is implemented by VPIphotonics software.
Iso-spin Dependent Microscopic Optical Model Potential Based on Dirac Bruckner Haretree Fock Method
无
2011-01-01
The microscopic optical model is investigated in the Dirac-Brueckner-Hartree-Fock (DBHF) framework with Bonn B meson exchange potential. Both real and imaginary parts of isospin-dependent self-energies are derived from a strict projection
Xin, Q.; Gong, P.; Li, W.
2015-02-01
Modeling vegetation photosynthesis is essential for understanding carbon exchanges between terrestrial ecosystems and the atmosphere. The radiative transfer process within plant canopies is one of the key drivers that regulate canopy photosynthesis. Most vegetation cover consists of discrete plant crowns, of which the physical observation departs from the underlying assumption of a homogenous and uniform medium in classic radiative transfer theory. Here we advance the Geometric Optical Radiative Transfer (GORT) model to simulate photosynthesis activities for discontinuous plant canopies. We separate radiation absorption into two components that are absorbed by sunlit and shaded leaves, and derive analytical solutions by integrating over the canopy layer. To model leaf-level and canopy-level photosynthesis, leaf light absorption is then linked to the biochemical process of gas diffusion through leaf stomata. The canopy gap probability derived from GORT differs from classic radiative transfer theory, especially when the leaf area index is high, due to leaf clumping effects. Tree characteristics such as tree density, crown shape, and canopy length affect leaf clumping and regulate radiation interception. Modeled gross primary production (GPP) for two deciduous forest stands could explain more than 80% of the variance of flux tower measurements at both near hourly and daily time scales. We also demonstrate that the ambient CO2 concentration influences daytime vegetation photosynthesis, which needs to be considered in state-of-the-art biogeochemical models. The proposed model is complementary to classic radiative transfer theory and shows promise in modeling the radiative transfer process and photosynthetic activities over discontinuous forest canopies.
Nonlocal dispersive optical model ingredients for ${}^{40}$Ca
Mahzoon, M H; Dickhoff, W H; Dussan, H; Waldecker, S J
2013-01-01
A comprehensive description of all single-particle properties associated with the nucleus ${}^{40}$Ca has been generated by employing a nonlocal dispersive optical potential capable of simultaneously reproducing all relevant data above and below the Fermi energy. We gather all relevant functional forms and the numerical values of the parameters in this contribution.
Modeling delamination due to thermal stress in optical storage media
Nkansah, M. A.; Evans, K. E.
1990-04-01
Finite element analysis is used to calculate the shape of blisters formed in bilayer optical storage media due to the buildup of thermal stresses during laser writing. It is shown that practically usable blisters may be expected to form in a time period of about 15 ns. Such a thermal stress delamination process may also precede melting in conventional pit formation processes.
Advanced optical modelling of dynamically deposited silicon nitride layers
Borojevic, N.; Hameiri, Z.; Winderbaum, S.
2016-07-01
Dynamic deposition of silicon nitrides using in-line plasma enhanced chemical vapor deposition systems results in non-uniform structure of the dielectric layer. Appropriate analysis of such layers requires the optical characterization to be performed as a function of the layer's depth. This work presents a method to characterize dynamically deposited silicon nitride layers. The method is based on the fitting of experimental spectroscopic ellipsometry data via grading of Tauc-Lorentz optical parameters through the depth of the layer. When compared with the standard Tauc-Lorentz fitting procedure, used in previous studies, the improved method is demonstrating better quality fits to the experimental data and revealing more accurate optical properties of the dielectric layers. The most significant advantage of the method is the ability to extract the depth profile of the optical properties along the direction of the layer normal. This is enabling a better understanding of layers deposited using dynamic plasma enhanced chemical vapor deposition systems frequently used in the photovoltaic industry.
Ruiz Moreno, Sergio; Guitart Felip, Jorge
1993-01-01
The authors present a simple model of a travelling wave semiconductor optical amplifier with an appreciable degree of saturation. The model uses a particular way of linearising the total carrier recombination R(N) to find useful expressions for the saturation parameter and/or the carrier lifetime. By combining these expressions and the gain measurements realised, it is possible to establish the dependence between the mentioned parameters and the input optical power. Peer Reviewed
Second Approximation Model for Optical Head in Super High Density Storage Technology
无
2000-01-01
The paper presents second approximation model for optical head in super high-density storage technology firstly and it is an important part for three grades approximate model of ultra-small-size quantum well corn-shaped laser and simulative calculations. It supplies the important and useful results for the NFOD optical head design with ultra thin active layer and ultra small spot laser.
Numerical models and experiment of air flow in a simulation box for optical wireless communications
Latal Jan
2016-01-01
Full Text Available In this article, the authors focused on real measurements of mechanical turbulence generated by ventilators in the simulation box for Optical Wireless Communications. The mechanical turbulences disturb the optical beam that propagates along the central axis of the simulation box. The aim of authors is to show the effect of mechanical turbulence on optical beams at different heights in the simulation box. In the Ansys Fluent, we created numerical models which were then compared with real measurements. Authors compared the real and numerical models according to statistical methods.
A general numerical solution of dispersion relations for the nuclear optical model
Capote, R; Quesada, J M; Capote, Roberto; Molina, Alberto; Quesada, Jose Manuel
2001-01-01
A general numerical solution of the dispersion integral relation between the real and the imaginary parts of the nuclear optical potential is presented. Fast convergence is achieved by means of the Gauss-Legendre integration method, which offers accuracy, easiness of implementation and generality for dispersive optical model calculations. The use of this numerical integration method in the optical-model parameter search codes allows for a fast and accurate dispersive analysis. PACS number(s): 11.55.Fv, 24.10.Ht, 02.60.Jh
Light Path Model of Fiber Optic Liquid Level Sensor Considering Residual Liquid Film on the Wall
Zhijun Zhang
2015-01-01
Full Text Available The working principle of the refractive-type fiber optic liquid level sensor is analyzed in detail based on the light refraction principle. The optic path models are developed in consideration of common simplification and the residual liquid film on the glass tube wall. The calculating formulae for the model are derived, constraint conditions are obtained, influencing factors are discussed, and the scopes and skills of application are analyzed through instance simulations. The research results are useful in directing the correct usage of the fiber optic liquid level sensor, especially in special cases, such as those involving viscous liquid in the glass tube monitoring.
Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Drees, K A; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N
2003-10-24
We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5
energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.
Investigation of the energy dependence of the orbital light curve in LS 5039
Chang, Z.; Zhang, S.; Ji, L.; Chen, Y. P.; Kretschmar, P.; Kuulkers, E.; Collmar, W.; Liu, C. Z.
2016-11-01
LS 5039 is so far the best-studied γ-ray binary system at multiwavelength energies. A time-resolved study of its spectral energy distribution (SED) shows that above 1 keV its power output is changing along its binary orbit as well as being a function of energy. To disentangle the energy dependence of the power output as a function of orbital phase, we investigated in detail the orbital light curves as derived with different telescopes at different energy bands. We analysed the data from all existing International Gamma-Ray Astrophysics Laboratory (INTEGRAL)/INTEGRAL on-board Imager/INTEGRAL Soft Gamma-Ray Imager observations of the source and generated the most up-to-date orbital light curves at hard X-ray energies. In the γ-ray band, we carried out orbital phase-resolved analysis of Fermi-Large Area Telescope (LAT) data between 30 MeV and 10 GeV in five different energy bands. We found that, at ≲100 MeV and ≳1 TeV the peak of the γ-ray emission is near orbital phase 0.7, while between ˜100 MeV and ˜1 GeV it moves close to orbital phase 1.0 in an orbital anticlockwise manner. This result suggests that the transition region in the SED at soft γ-rays (below a hundred MeV) is related to the orbital phase interval of 0.5-1.0 but not to the one of 0.0-0.5, when the compact object is `behind' its companion. Another interesting result is that between 3 and 20 GeV no orbital modulation is found, although Fermi-LAT significantly (˜18σ) detects LS 5039. This is consistent with the fact that at these energies, the contributions to the overall emission from the inferior conjunction phase region (INFC, orbital phase 0.45-0.9) and from the superior conjunction phase region (orbital phase 0.9-0.45) are equal in strength. At TeV energies the power output is again dominant in the INFC region and the flux peak occurs at phase ˜0.7.
Alt, C; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Bunccic, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Gazdzicki, M; Genchev, V; Georgopoulos, G; Gladysz, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kliemant, M; Kniege, S; Kolesnikov, V I; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Kresan, D; Van Leeuwen, M; Lévai, P; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, St; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Pikna, M; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Stefanek, G; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Yoo, I K
2009-01-01
We present recent measurements of the energy dependence of event-by-event fluctuations in the K/pi and (p + \\bar{p})/pi multiplicity ratios in heavy ion collisions at the CERN SPS. The particle ratio fluctuations were obtained for central Pb+Pb collisions at five collision energies, \\sqrt{s_{_{NN}}}, between 6.3 and 17.3 GeV. After accounting for the effects of finite-number statistics and detector resolution, we extract the strength of non-statistical fluctuations at each energy. For the K/pi ratio, larger fluctuations than expected for independent particle production are found at all collision energies. The fluctuations in the (p + \\bar{p})/pi ratio are smaller than expectations from independent particle production, indicating correlated pion and proton production from resonance decays. For both ratios, the deviation from purely statistical fluctuations shows an increase towards lower collision energies. The results are compared to transport model calculations, which fail to describe the energy dependence o...
Modeling, Simulation, and Characterization of Electro-Optic Polymer Waveguide Devices.
Ma, Jiong
The primary objective of this thesis is to investigate the properties of optical polymer waveguides and switches, develop a phenomenological CAD tool, and to use this phenomenological tool to design optical polymer devices for high-speed interconnects in VLSI systems. In the investigations of optical polymer waveguides, a new phenomenological bleaching model that is able to predict optical index profiles for photobleached polymer films was developed. The theoretical model shows good agreement with measured results for the effective index and optical field distributions of waveguides, and the absorption of films. Based on this bleaching model, we can predict the index profile for polymer channel waveguides and formulate design rules for active optical switches and modulators. The model has been successfully applied to photobleached PMMA/DR1 and Ultem/DEDR1 waveguides. An experimental technique to determine the poling -induced optical birefringence and optical nonlinearity is also discussed. In this technique, absorption measurements are performed immediately after poling. The poling-induced index changes as a function of wavelength are obtained from the absorption changes using a Kramers-Kronig transformation. An alternative method for predicting the poling-induced index changes, requiring a combination of waveguide measurement techniques and order parameter calculations, exhibits good agreement. By combining the poling effects with the photobleaching index profile, a CAD tool has been developed to calculate the optical field distribution and loss which allows the design of active electro-optical modulators. Using the CAD tool together with an equivalent circuit model of electro-optic polymer switches, circuit level comparisons of a CMOS strip line interconnect with an external polymer modulator interconnect were performed in terms of power dissipation, bandwidth, and connection density. HSPICE was used as a circuit simulation tool. Based on this analysis, it is
New optical and radio frequency angular tropospheric refraction models for deep space applications
Berman, A. L.; Rockwell, S. T.
1976-01-01
The development of angular tropospheric refraction models for optical and radio frequency usage is presented. The models are compact analytic functions, finite over the entire domain of elevation angle, and accurate over large ranges of pressure, temperature, and relative humidity. Additionally, FORTRAN subroutines for each of the models are included.
Niu Chun-Hui; Li Zhi-Yuan; Ye Jia-Sheng; Gu Ben-Yuan
2005-01-01
Scalar diffraction theory, although simple and efficient, is too rough for analysing diffractive micro-optical elements.Rigorous vectorial diffraction theory requires extensive numerical efforts, and is not a convenient design tool. In this paper we employ a simple approximate vectorial diffraction model which combines the principle of the scalar diffraction theory with an approximate local field model to analyse the diffraction of optical waves by some typical two-dimensional diffractive micro-optical elements. The TE and TM polarization modes are both considered. We have found that the approximate vectorial diffraction model can agree much better with the rigorous electromagnetic simulation results than the scalar diffraction theory for these micro-optical elements.
Solar optical codes evaluation for modeling and analyzing complex solar receiver geometries
Yellowhair, Julius; Ortega, Jesus D.; Christian, Joshua M.; Ho, Clifford K.
2014-09-01
Solar optical modeling tools are valuable for modeling and predicting the performance of solar technology systems. Four optical modeling tools were evaluated using the National Solar Thermal Test Facility heliostat field combined with flat plate receiver geometry as a benchmark. The four optical modeling tools evaluated were DELSOL, HELIOS, SolTrace, and Tonatiuh. All are available for free from their respective developers. DELSOL and HELIOS both use a convolution of the sunshape and optical errors for rapid calculation of the incident irradiance profiles on the receiver surfaces. SolTrace and Tonatiuh use ray-tracing methods to intersect the reflected solar rays with the receiver surfaces and construct irradiance profiles. We found the ray-tracing tools, although slower in computation speed, to be more flexible for modeling complex receiver geometries, whereas DELSOL and HELIOS were limited to standard receiver geometries such as flat plate, cylinder, and cavity receivers. We also list the strengths and deficiencies of the tools to show tool preference depending on the modeling and design needs. We provide an example of using SolTrace for modeling nonconventional receiver geometries. The goal is to transfer the irradiance profiles on the receiver surfaces calculated in an optical code to a computational fluid dynamics code such as ANSYS Fluent. This approach eliminates the need for using discrete ordinance or discrete radiation transfer models, which are computationally intensive, within the CFD code. The irradiance profiles on the receiver surfaces then allows for thermal and fluid analysis on the receiver.
Optical-Model Description of Time-Reversal Violation
Hnizdo, V
1994-01-01
A time-reversal-violating spin-correlation coefficient in the total cross section for polarized neutrons incident on a tensor rank-2 polarized target is calculated by assuming a time-reversal-noninvariant, parity-conserving ``five-fold" interaction in the neutron-nucleus optical potential. Results are presented for the system $n + {^{165}{\\rm Ho}}$ for neutron incident energies covering the range 1--20 MeV. From existing experimental bounds, a strength of $2 \\pm 10$ keV is deduced for the real and imaginary parts of the five-fold term, which implies an upper bound of order $10^{-4}$ on the relative $T$-odd strength when compared to the central real optical potential.
AeroCom INSITU Project: Comparing modeled and measured aerosol optical properties
Andrews, Elisabeth; Schmeisser, Lauren; Schulz, Michael; Fiebig, Markus; Ogren, John; Bian, Huisheng; Chin, Mian; Easter, Richard; Ghan, Steve; Kokkola, Harri; Laakso, Anton; Myhre, Gunnar; Randles, Cynthia; da Silva, Arlindo; Stier, Phillip; Skeie, Ragnehild; Takemura, Toshihiko; van Noije, Twan; Zhang, Kai
2016-04-01
AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data has the unique property of being traceable to physical standards, which is an asset in accomplishing the overall goal of bettering the accuracy of aerosols processes and the predicative capability of global climate models. Here we compare dry, in-situ aerosol scattering and absorption data from ~75 surface, in-situ sites from various global aerosol networks (including NOAA, EUSAAR/ACTRIS and GAW) with a simulated optical properties from a suite of models participating in the AeroCom project. We report how well models reproduce aerosol climatologies for a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis suggest substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography. Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol behaviors, for example, the tendency of in-situ single scattering albedo to decrease with decreasing aerosol extinction coefficient. The endgoal of the INSITU project is to identify specific
Modeling and compensation of transmitter nonlinearity in coherent optical OFDM.
Amiralizadeh, Siamak; Nguyen, An T; Rusch, Leslie A
2015-10-05
We present a comprehensive study of nonlinear distortions from an optical OFDM transmitter. Nonlinearities are introduced by the combination of effects from the digital-to-analog converter (DAC), electrical power amplifier (PA) and optical modulator in the presence of high peak-to-average power ratio (PAPR). We introduce parameters to quantify the transmitter nonlinearity. High input backoff avoids OFDM signal compression from the PA, but incurs high penalties in power efficiency. At low input backoff, common PAPR reduction techniques are not effective in suppressing the PA nonlinear distortion. A bit error distribution investigation shows a technique combining nonlinear predistortion with PAPR mitigation could achieve good power efficiency by allowing low input backoff. We use training symbols to extract the transmitter nonlinear function. We show that piecewise linear interpolation (PLI) leads to an accurate transmitter nonlinearity characterization. We derive a semi-analytical solution for bit error rate (BER) that validates the PLI approximation accurately captures transmitter nonlinearity. The inverse of the PLI estimate of the nonlinear function is used as a predistorter to suppress transmitter nonlinearity. We investigate performance of the proposed scheme by Monte Carlo simulations. Our simulations show that when DAC resolution is more than 4 bits, BER below forward error correction limit of 3.8 × 10(-3) can be achieved by using predistortion with very low input power backoff for electrical PA and optical modulator.
Thekkayil, Remyamol [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080 (India); Gopinath, Pramod [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India)
2014-08-01
Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high β{sub eff} (230 cm GW{sup −1}) and low limiting threshold at 150 μJ.
Computer Modeling and Simulation Evaluation of High Power LED Sources for Secondary Optical Design
SU Hong-dong; WANG Ya-jun; DONG Ji-yang; CHEN Zhong
2007-01-01
Proposed and demonstrated is a novel computer modeling method for high power light emitting diodes(LEDs). It contains geometrical structure and optical property of high power LED as well as LED dies definition with its spatial and angular distribution. Merits and non-merits of traditional modeling methods when applied to high power LEDs based on secondary optical design are discussed. Two commercial high power LEDs are simulated using the proposed computer modeling method. Correlation coefficient is proposed to compare and analyze the simulation results and manufacturing specifications. The source model is precisely demonstrated by obtaining above 99% in correlation coefficient with different surface incident angle intervals.
Aden, Abdirahman; Anthony, Arthi; Brigi, Carel; Merchant, Muhammad Sabih; Siraj, Huda; Tomlins, Peter H.
2017-07-01
Dental enamel mineral loss is multifactorial and is consequently explored using a variety of in vitro models. Important factors include the presence of acidic pH and its specific ionic composition, which can both influence lesion characteristics. Optical coherence tomography (OCT) has been demonstrated as a promising tool for studying dental enamel demineralization. However, OCT-based characterization and comparison of demineralization model dynamics are challenging without a consistent experimental environment. Therefore, an automated four-dimensional OCT system was integrated with a multispecimen flow cell to measure and compare the optical properties of subsurface enamel demineralization in different models. This configuration was entirely automated, thus mitigating any need to disturb the specimens and ensuring spatial registration of OCT image volumes at multiple time points. Twelve bovine enamel disks were divided equally among three model groups. The model demineralization solutions were citric acid (pH 3.8), acetic acid (pH 4.0), and acetic acid with added calcium and phosphate (pH 4.4). Bovine specimens were exposed to the solution continuously for 48 h. Three-dimensional OCT data were obtained automatically from each specimen at a minimum of 1-h intervals from the same location within each specimen. Lesion dynamics were measured in terms of the depth below the surface to which the lesion extended and the attenuation coefficient. The net loss of surface enamel was also measured for comparison. Similarities between the dynamics of each model were observed, although there were also distinct characteristic differences. Notably, the attenuation coefficients showed a systematic offset and temporal shift with respect to the different models. Furthermore, the lesion depth curves displayed a discontinuous increase several hours after the initial acid challenge. This work demonstrated the capability of OCT to distinguish between different enamel demineralization
Progress in modeling polarization optical components for the Daniel K. Inouye Solar Telescope
Sueoka, Stacey Ritsuyo; Harrington, David M.
2016-07-01
The DKIST will have a suite of first-light polarimetric instrumentation requiring precise calibration of a complex articulated optical path. The optics are subject to large thermal loads caused by the 300Watts of collected solar irradiance across the 5 arc minute field of view. The calibration process requires stable optics to generate known polarization states. We present modeling of several optical, thermal and mechanical effects of the calibration optics, the first transmissive optical elements in the light path, because they absorb substantial heat. Previous studies showed significant angle of incidence effects from the f/13 converging beam and the 5 arc minute field of view, but were only modeled at a single nominal temperature. New thermal and polarization modeling of these calibration retarders shows heating causes significant stability limitations both in time and with field caused by the bulk temperature rise along with depth and radial thermal gradients. Modeling efforts include varying coating and material absorption, Mueller matrix stability estimates and mitigation efforts.
Internal model control of a fast steering mirror for electro-optical fine tracking
Xia, Yun-xia; Bao, Qi-liang; Wu, Qiong-yan
2010-11-01
The objective of this research is to develop advanced control methods to improve the bandwidth and tracking precision of the electro-optical fine tracking system using a fast steering mirror (FSM). FSM is the most important part in this control system. The model of FSM is established at the beginning of this paper. Compared with the electro-optical fine tracking system with ground based platform, the electro-optical fine tracking system with movement based platform must be a wide bandwidth and a robustness system. An advanced control method based on internal model control law is developed for electro-optical fine tracking system. The IMC is an advanced algorithm. Theoretically, it can eliminate disturbance completely and make sure output equals to input even there is model error. Moreover, it separates process to the system dynamic characteristic and the object perturbation. Compared with the PID controller, the controller is simpler and the parameter regulation is more convenient and the system is more robust. In addition, we design an improved structure based on classic IMC. The tracking error of the two-port control system is much better than which of the classic IMC. The simulation results indicate that the electro-optical control system based on the internal model control algorithm is very effective. It shows a better performance at the tracing precision and the disturbance suppresses. Thus a new method is provided for the high-performance electro-optical fine tracking system.
Hannesdottir, H.; Gudmundsson, J. T.
2016-10-01
The effects of including the singlet metastable molecule O2(b{{}1}Σ\\text{g}+ ) in the discharge model of a capacitively coupled rf driven oxygen discharge are explored. We furthermore examine the addition of energy-dependent secondary electron emission yields from the electrodes to the discharge model. The one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 is used for this purpose, with the oxygen discharge model considering the species {{\\text{O}}2}≤ft({{\\text{X}}3}Σ\\text{g}-\\right) , {{\\text{O}}2}≤ft({{\\text{a}}1}{{Δ }\\text{g}}\\right) , {{\\text{O}}2}≤ft({{\\text{b}}1}Σ\\text{g}+\\right) , O(3P), O(1D), \\text{O}2+ , O+, O-, and electrons. The effects on particle density profiles, the electron heating rate profile, the electron energy probability function and the sheath width are explored including and excluding the metastable oxygen molecules and secondary electron emission. Earlier we have demonstrated that adding the metastable O2(a{{}1}{{Δ }\\text{g}} ) to the discharge model changes the electron heating from having contributions from both bulk and sheath heating to being dominated by sheath heating for pressures above 50 mTorr. We find that including the metastable O2(b{{}1}Σ\\text{g}+ ) further decreases the ohmic heating and the effective electron temperature in the bulk region. The effective electron temperature in the electronegative core is found to be less than 1 eV in the pressure range 50-200 mTorr which agrees with recent experimental findings. Furthermore, we find that including an energy-dependent secondary electron emission yield for \\text{O}2+ -ions has a significant influence on the discharge properties, including decreased sheath width.
Numerical Modelling of Spontaneous Emission in Optical Parametric Amplifiers
Friis, Søren Michael Mørk; Andersen, Ulrik Lund; Rottwitt, Karsten
2013-01-01
Fiber optical parametric processes offer a wide range of applications including phase sensitive as well as phase insensitive amplification, wavelength conversion and signal regeneration. One of the difficult challenges is any of these applications is to predict their associated noise performance....... However, it is well accepted that one contribution to the noise performance originates from vacuum fluctuations. In this work we show a novel approach to predict the spontaneous radiation from a parametric amplifier. In the approach the propagating fields are treated as a sum of a classical mean field...
Laser energy dependence of valley polarization in transition-metal dichalcogenides
Tatsumi, Yuki; Ghalamkari, Kazu; Saito, Riichiro
2016-12-01
Photoabsorption spectra by circular polarized light in transition-metal dichalcogenides are calculated as a function of laser excitation energy. Although the 100% valley polarization occurs at the K point of the Brillouin zone, the difference of the absorption intensity for left-handed and right-handed circular polarized light becomes maximum at about 1 eV higher energy than the direct energy band gap. The maximum intensity difference corresponds to the so-called Λ valley in the Brillouin zone. In order to understand valley polarization, analytic formula of optical absorption is given by tight-binding method.
Q. Xin
2015-02-01
Full Text Available Modeling vegetation photosynthesis is essential for understanding carbon exchanges between terrestrial ecosystems and the atmosphere. The radiative transfer process within plant canopies is one of the key drivers that regulate canopy photosynthesis. Most vegetation cover consists of discrete plant crowns, of which the physical observation departs from the underlying assumption of a homogenous and uniform medium in classic radiative transfer theory. Here we advance the Geometric Optical Radiative Transfer (GORT model to simulate photosynthesis activities for discontinuous plant canopies. We separate radiation absorption into two components that are absorbed by sunlit and shaded leaves, and derive analytical solutions by integrating over the canopy layer. To model leaf-level and canopy-level photosynthesis, leaf light absorption is then linked to the biochemical process of gas diffusion through leaf stomata. The canopy gap probability derived from GORT differs from classic radiative transfer theory, especially when the leaf area index is high, due to leaf clumping effects. Tree characteristics such as tree density, crown shape, and canopy length affect leaf clumping and regulate radiation interception. Modeled gross primary production (GPP for two deciduous forest stands could explain more than 80% of the variance of flux tower measurements at both near hourly and daily time scales. We also demonstrate that the ambient CO2 concentration influences daytime vegetation photosynthesis, which needs to be considered in state-of-the-art biogeochemical models. The proposed model is complementary to classic radiative transfer theory and shows promise in modeling the radiative transfer process and photosynthetic activities over discontinuous forest canopies.
Simulation and experimental results of optical and thermal modeling of gold nanoshells.
Ghazanfari, Lida; Khosroshahi, Mohammad E
2014-09-01
This paper proposes a generalized method for optical and thermal modeling of synthesized magneto-optical nanoshells (MNSs) for biomedical applications. Superparamagnetic magnetite nanoparticles with diameter of 9.5 ± 1.4 nm are fabricated using co-precipitation method and subsequently covered by a thin layer of gold to obtain 15.8 ± 3.5 nm MNSs. In this paper, simulations and detailed analysis are carried out for different nanoshell geometry to achieve a maximum heat power. Structural, magnetic and optical properties of MNSs are assessed using vibrating sample magnetometer (VSM), X-ray diffraction (XRD), UV-VIS spectrophotometer, dynamic light scattering (DLS), and transmission electron microscope (TEM). Magnetic saturation of synthesized magnetite nanoparticles are reduced from 46.94 to 11.98 emu/g after coating with gold. The performance of the proposed optical-thermal modeling technique is verified by simulation and experimental results.
Benchaabane, Aida; Ben Hamed, Zied; Kouki, Fayçal; Abderrahmane Sanhoury, Mohamed; Zellama, Kacem; Zeinert, Andreas; Bouchriha, Habib
2014-04-01
The effective medium model is applied to investigate the optical properties of hybrid nanocomposite layers of Polyvinylcarbazole (PVK) and nanoparticles of Zinc Selenide (ZnSe). Thin films of PVK:ZnSe nanocomposites show a porous microstructure with pore diameters of 500 nm. Numerical calculations led to the determination of optical constants such as the refractive index n, the extinction coefficient k, the dielectric permittivity ɛ, and absorption coefficient α. Using common theoretical models, we have determined the Cauchy parameters of the refractive index, namely, static ɛs and lattice ɛ∞ dielectric constants as well as the plasma frequency ωp, carrier density to effective mass ratio N/me*, and the optical conductivity σoc. We show that the optical band gap energy Eg of the nanocomposite structure decreases slightly upon the increase of the nanoparticles volume fraction and is in good agreement with the Vegard law.
Microscopic modeling of the effect of phonons on the optical properties of solid-state emitters
Norambuena, Ariel; Reyes, Sebastián A.; Mejía-Lopéz, José; Gali, Adam; Maze, Jerónimo R.
2016-10-01
Understanding the effect of vibrations in optically active nanosystems is crucial for successfully implementing applications in molecular-based electro-optical devices, quantum information communications, single photon sources, and fluorescent markers for biological measurements. Here, we present a first-principles microscopic description of the role of phonons on the isotopic shift presented in the optical emission spectrum associated to the negatively charged silicon-vacancy color center in diamond. We use the spin-boson model and estimate the electron-phonon interactions using a symmetrized molecular description of the electronic states and a force-constant model to describe molecular vibrations. Group theoretical arguments and dynamical symmetry breaking are presented in order to explain the optical properties of the zero-phonon line and the isotopic shift of the phonon sideband.
Dispersion model for optical thin films applicable in wide spectral range
Franta, Daniel; Nečas, David; Ohlídal, Ivan; Giglia, Angelo
2015-09-01
In the optics industry thin film systems are used to construct various interference devices such as antireflective coatings, high-reflectance mirrors, beam splitters and filters. The optical characterization of complex optical systems can not be performed by measurements only in the short spectral range in which the interference devices will be employed because the measured data do not contain sufficient information about all relevant parameters of these systems. The characterization of film materials requires the extension of the spectral range of the measurements to the IR region containing phonon absorption and to the UV region containing the electronic excitations. However, this leads to necessity of a dispersion model suitable for the description of the dielectric response in the wide spectral range. Such model must respect the physical conditions following from theory of dispersion, particularly Kramers-Kronig relations and integrability imposed by sum rules. This work presents the construction of a universal dispersion model composed from individual contributions representing both electronic and phonon excitations. The efficiency of presented model is given by the fact that all the contributions are described by analytical expressions. It is shown that the model is suitable for precise modeling of spectral dependencies of optical constants of a broad class of materials used in the optical industry for thin film systems such as MgF2, SiO2, Al2O3, HfO2, Ta2O5 and TiO2 in the spectral range from far IR to vacuum UV.
Cereal Yield Modeling in Finland Using Optical and Radar Remote Sensing
Jouko Kleemola
2010-09-01
Full Text Available During 1996–2006, the Ministry of Agriculture and Forestry in Finland (MAFF, MTT Agrifood Research and the Finnish Geodetic Institute performed a joint remote sensing satellite research project. It evaluated the applicability of optical satellite (Landsat, SPOT data for cereal yield estimations in the annual crop inventory program. Four Optical Vegetation Indices models (I: Infrared polynomial, II: NDVI, III: GEMI, IV: PARND/FAPAR were validated to estimate cereal baseline yield levels (yb using solely optical harmonized satellite data (Optical Minimum Dataset. The optimized Model II (NDVI yb level was 4,240 kg/ha (R2 0.73, RMSE 297 kg/ha for wheat and 4390 kg/ha (R2 0.61, RMSE 449 kg/ha for barley and Model I yb was 3,480 kg/ha for oats (R2 0.76, RMSE 258 kg/ha. Optical VGI yield estimates were validated with CropWatN crop model yield estimates using SPOT and NOAA data (mean R2 0.71, RMSE 436 kg/ha and with composite SAR/ASAR and NDVI models (mean R2 0.61, RMSE 402 kg/ha using both reflectance and backscattering data. CropWatN and Composite SAR/ASAR & NDVI model mean yields were 4,754/4,170 kg/ha for wheat, 4,192/3,848 kg/ha for barley and 4,992/2,935 kg/ha for oats.
Model-based defect detection on structured surfaces having optically unresolved features.
O'Connor, Daniel; Henning, Andrew J; Sherlock, Ben; Leach, Richard K; Coupland, Jeremy; Giusca, Claudiu L
2015-10-20
In this paper, we demonstrate, both numerically and experimentally, a method for the detection of defects on structured surfaces having optically unresolved features. The method makes use of synthetic reference data generated by an observational model that is able to simulate the response of the selected optical inspection system to the ideal structure, thereby providing an ideal measure of deviation from nominal geometry. The method addresses the high dynamic range challenge faced in highly parallel manufacturing by enabling the use of low resolution, wide field of view optical systems for defect detection on surfaces containing small features over large regions.
Lin, Alexander J.; Konecky, Soren D.; Rice, Tyler B.; Green, Kim N.; Choi, Bernard; Durkin, Anthony J.; Tromberg, Bruce J.
2012-02-01
Early neurovascular coupling (NVC) changes in Alzheimer's disease can potentially provide imaging biomarkers to assist with diagnosis and treatment. Previous efforts to quantify NVC with intrinsic signal imaging have required assumptions of baseline optical pathlength to calculate changes in oxy- and deoxy-hemoglobin concentrations during evoked stimuli. In this work, we present an economical spatial frequency domain imaging (SFDI) platform utilizing a commercially available LED projector, camera, and off-the-shelf optical components suitable for imaging dynamic optical properties. The fast acquisition platform described in this work is validated on silicone phantoms and demonstrated in neuroimaging of a mouse model.
A Novel Model of Resolving Contention in Optical Burst Switched Networks
Huang Anpeng(黄安鹏); Xie Linzhen; Li Jingcong; Li Zhengbin; Xu Anshi
2004-01-01
A Novel segmentation and feedback model (SFM) applied to resolve collision has been proposed. The SFM is featured with Burst Segmentation and Prioritized Feedback (BSPF) that are used to provide quality of service (QoS) and realize high throughput and faster switching in the optical burst switched networks. Simulation and performance analyses show that the SFM effectively avoid collision in optical burst switching (OBS). Long delay time of deflection routing and immature technology of wavelength converter and optical buffer are not employed in the SFM. The SFM not only realizes quick switching but also allows preemption for higher priority bursts.
Mouse mtDNA mutant model of Leber hereditary optic neuropathy.
Lin, Chun Shi; Sharpley, Mark S; Fan, Weiwei; Waymire, Katrina G; Sadun, Alfredo A; Carelli, Valerio; Ross-Cisneros, Fred N; Baciu, Peter; Sung, Eric; McManus, Meagan J; Pan, Billy X; Gil, Daniel W; Macgregor, Grant R; Wallace, Douglas C
2012-12-04
An animal model of Leber hereditary optic neuropathy (LHON) was produced by introducing the human optic atrophy mtDNA ND6 P25L mutation into the mouse. Mice with this mutation exhibited reduction in retinal function by elecroretinogram (ERG), age-related decline in central smaller caliber optic nerve fibers with sparing of larger peripheral fibers, neuronal accumulation of abnormal mitochondria, axonal swelling, and demyelination. Mitochondrial analysis revealed partial complex I and respiration defects and increased reactive oxygen species (ROS) production, whereas synaptosome analysis revealed decreased complex I activity and increased ROS but no diminution of ATP production. Thus, LHON pathophysiology may result from oxidative stress.
Performance evaluation of generalized M-modeled atmospheric optical communications links
Lopez-Gonzalez, Francisco J.; Garrido-Balsellss, José María; Jurado-Navas, Antonio;
2016-01-01
, the behavior of the atmospheric optical channel is treated as a superposition of a finite number of Generalized-K distributed sub-channels, controlled by a discrete Negative-Binomial distribution dependent on the turbulence parameters. Unlike other studies, here, the closed-form mathematical expressions......In this paper, the performance analysis of atmospheric optical communications links is analyzed in terms of the average bit error rate. To this end, the optical irradiance scintillation due to the turbulence effects is modeled by a generalization of the M´alaga or M distribution. In particular...
Theoretical model of the modulation transfer function for fiber optic taper
Wang, Yaoxiang; Tian, Weijian; Bin, XiangLi
2005-02-01
Fiber optic taper has been used more and more widely as a relay optical component in the integrated taper assembly image intensified sensors for military and medical imaging application. In this paper, the transmission characteristic of energy in the taper is analyzed, and following the generalized definition of the modulation transfer function for sampled imaging system, a spatial averaged impulse response and a corresponding MTF component that are inherent in the sampling process of taper are deduced, and the mathematical model for evaluating the modulation transfer function of fiber optic taper is built. Finally, the dynamic and static modulation transfer function curves simulated by computer have been exhibited.
Measurement of the energy dependence of the muon transfer rate from hydrogen to higher-Z gases
Bakalov, Dimitar; Stoilov, Mihail; Vacchi, Andrea
2014-01-01
The recent Lamb shift experiment at PSI and the apparent incompatibility of the proton radii extracted using different methods revived the interest in the measurement of the hyperfine splitting in the ground state of muonic hydrogen as an alternative possibility for the experimental comparison of ordinary and muonic hydrogen spectroscopy data about the proton electromagnetic structure. The efficiency of the method developed for this measurement has been shown to critically depend on the energy dependence of the rate of muon transfer from hydrogen to heavier gases in the epithermal range. The available experimental data provide only qualitative information on the energy dependence, and the detailed theoretical predictions have not yet been tested. The present paper outlines an experimental method for the quantitative measurement of the muon transfer rate based on a series of repeated measurements of the muon transfer rate in a mixture of hydrogen and the gas of interest with appropriate concentration and densi...
Lipponer, M. A.; Reutzel, M.; Dürr, M.; Höfer, U.
2016-11-01
The adsorption dynamics of the datively bonded trimethylamine (TMA) on Si(001) was investigated by means of molecular beam techniques. The initial sticking probability s0 of TMA on Si(001) was measured as a function of kinetic energy at two different surface temperatures (230 and 550 K). At given surface temperature, s0 was found to decrease with increasing kinetic energy (0.1 to 0.6 eV) indicating a non-activated reaction channel. At increased surface temperature, s0 is reduced due to the onset of desorption into the gas phase. The energy dependence of s0 is compared to the results for the adsorption of tetrahydrofuran (THF) on Si(001), which reacts via a datively bonded intermediate into a covalently bound final state. As s0 follows the same energy dependence both for TMA and THF, the datively bonded intermediate state is concluded to dominate the reaction dynamics in the latter case as well.
戈迪; 蔡阳健; 林强
2005-01-01
By use of a tensor method, the transform formulae for the beam coherence-polarization matrix of the partially polarized Gaussian Schell-model (GSM) beams through aligned and misaligned optical systems are derived. As an example, the propagation properties of the partially polarized GSM beam passing through a misaligned thin lens are illustrated numerically and discussed in detail. The derived formulae provide a convenient way to study the propagation properties of the partially polarized GSM beams through aligned and misaligned optical systems.
2012-09-30
1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Flocculation , Optics and Turbulence in the Community...www.phys.ocean.dal.ca/~phill LONG-TERM GOALS The goal of this research is to develop greater understanding of how the flocculation of fine-grained sediment...COVERED - 4. TITLE AND SUBTITLE Flocculation , Optics and Turbulence in the Community Sediment Transport Model System: Application of Oasis
2011-09-30
1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Flocculation , Optics and Turbulence in the Community...www.phys.ocean.dal.ca/~phill LONG-TERM GOALS The goal of this research is to develop greater understanding of how the flocculation of fine-grained...DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Flocculation , Optics and Turbulence in the Community Sediment Transport Model System
Liu, Na; Giessen, Harald
2008-12-22
In this paper, we demonstrate that metamaterials represent model systems for longitudinal and transverse magnetic coupling in the optical domain. In particular, such coupling can lead to fully parallel or antiparallel alignment of the magnetic dipoles at the lowest frequency resonance. Also, we present the design scheme for constructing three-dimensional metamaterials with solely magnetic interaction. Our concept could pave the way for achieving rather complicated magnetic materials with desired arrangements of magnetic dipoles at optical frequencies.
Effective-mass model and magneto-optical properties in hybrid perovskites
Yu, Z. G.
2016-01-01
Hybrid inorganic-organic perovskites have proven to be a revolutionary material for low-cost photovoltaic applications. They also exhibit many other interesting properties, including giant Rashba splitting, large-radius Wannier excitons, and novel magneto-optical effects. Understanding these properties as well as the detailed mechanism of photovoltaics requires a reliable and accessible electronic structure, on which models of transport, excitonic, and magneto-optical properties can be effici...
Lackovic, Marko; Bungarzeanu, Cristian
2006-01-01
The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet ...
Rahul Sharma; Subbajit Nandy; S P Bhattacharyya
2006-06-01
An energy-dependent partitioning scheme is explored for extracting a small number of eigenvalues of a real symmetric matrix with the help of genetic algorithm. The proposed method is tested with matrices of different sizes (30 × 30 to 1000 × 1000). Comparison is made with Löwdin's strategy for solving the problem. The relative advantages and disadvantages of the GA-based method are analyzed.
Abdelmadjid Maireche
2016-01-01
The main objective of this search work is to study a three dimensional space-phase modified Schrödinger equation with energy dependent potential plus three terms: , and is carried out. Together with the Boopp’s shift method and standard perturbation theory the new energy spectra shown to be dependent with new atomic quantum in the non-commutative three dimensional real spaces and phases symmetries (NC-3D: RSP) and we have also constructed the corresponding deformed noncommutative Hamiltonia...
Algebraic approach to electro-optic modulation of light: Exactly solvable multimode quantum model
Miroshnichenko, George P; Trifanov, Alexander I; Gleim, Artur V
2016-01-01
We theoretically study electro-optic light modulation based on the quantum model where the linear electro-optic effect and the externally applied microwave field result in the interaction between optical cavity modes. The model assumes that the number of interacting modes is finite and effects of the mode overlapping coefficient on the strength of the intermode interaction can be taken into account through dependence of the coupling coefficient on the mode characteristics. We show that, under certain conditions, the model is exactly solvable and, in the semiclassical approximation where the microwave field is treated as a classical mode, can be analyzed using the technique of the Jordan mappings for the su(2) Lie algebra. Analytical results are applied to study effects of light modulation on the frequency dependence of the photon counting rate. We also establish the conditions of validity of the semiclassical approximation by applying the methods of polynomially deformed Lie algebras for analysis of the model...
Optical modeling and physical performances evaluations for the JT-60SA ECRF antenna
Platania, P., E-mail: platania@ifp.cnr.it; Figini, L.; Farina, D.; Micheletti, D.; Moro, A.; Sozzi, C. [Istituto di Fisica del Plasma “P. Caldirola”, Consiglio Nazionale delle Ricerche, Via R. Cozzi 53, 20125, Milano (Italy); Isayama, A.; Kobayashi, T.; Moriyama, S. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)
2015-12-10
The purpose of this work is the optical modeling and physical performances evaluations of the JT-60SA ECRF launcher system. The beams have been simulated with the electromagnetic code GRASP® and used as input for ECCD calculations performed with the beam tracing code GRAY, capable of modeling propagation, absorption and current drive of an EC Gaussion beam with general astigmatism. Full details of the optical analysis has been taken into account to model the launched beams. Inductive and advanced reference scenarios has been analysed for physical evaluations in the full poloidal and toroidal steering ranges for two slightly different layouts of the launcher system.
Assessment of some optical model potentials in predicting neutron cross sections
Kumar, A.; Young, P.G.; Chadwick, M.B.
1998-03-01
Optical model potential parameters play an important role in the evaluation of nuclear data for applied purposes. The IAEA Coordinated Research Program on {open_quotes}Reference Input Parameter Library for Evaluation of Nuclear Data for Application in Nuclear Technology{close_quotes} aims to release a reference input file of various types of parameters for the evaluation of nuclear cross sections using nuclear model codes. Included in the parameter files are a collection of optical model potentials that are available in the literature to evaluate these cross sections. As part of this research program we assess the applicability of these potentials over a range of target mass and projectile energy.
Red tide optical index: in situ optics and remote sensing models
Cetinic, I.; Karp-Boss, L.; Boss, E.; Ragan, M. A.; Jones, B. H.
2007-05-01
Harmful Algal Blooms (HABs) are recurring events in the coastal ocean, and local economies that depend on beach and coastal use are often adversely affected by these events. Inherent optical properties (absorption and backscattering) of the HAB dinoflagellate Lingulodinium polyedrum were measured in order to develop specific index that would enable easier detection of this HAB organism in the field. It has been noticed that red to blue and red to green ratio of absorption in this species is much lower then other measured species. A red tide ratio was tested in the field during a red tide episode in the San Pedro Channel, using a Wetlabs acS flow-through system. The red tide index gave a distinguishable signal in areas where L.polyedrum was present. Remote sensing reflectance was calculated from field and laboratory IOP measurements, using reverse Quasi-Analythical Alghoritm and Hydrolight to evaluate if the red tide index can be detected in the remote sensing ocean color measurements.
Paula COPĂESCU
2009-12-01
Full Text Available Preliminary results obtained in developing a numerical model of laser light intensity transversedistribution into undeformed/deformed step index optical fiber are presented. The main purpose ofthe presented preliminary numerical modelling results consists in developing a simple method offiber optical sensors interrogation, especially concerning strain and pressure measurements. It is apotential important matter for aeronautical research and industry because of the more extendeduse of fibre optic sensors in aircraft manufacturing. The developed numerical model relies onsolving the equations of electromagnetic waves propagation into optical fibers by using the finiteelement method technique (FEM. The results of numerical simulation obtained by consideringsingle mode or multimode and various laser wavelengtsh are presented. One importantachievement reported in this paper consists in preliminary experimental results concerning themodification of laser intensity transverse distribution observed for multimode optical fiber with andwithout perpendicular mechanical load. The reported preliminary experimental results confirm tosome extent the predictions of numerical simulations regarding laser intensity distribution underlow and medium transverse mechanical load. One important conclusion of this paper consists inthe future development of fiber optic sensor interrogation techniques based on the reportedpreliminary experimental and numerical simulation results.
Ruley, John D.
1986-01-01
In the design of spacecraft for proper thermal balance, accurate information on the long-term optical behavior of the spacecraft outer skin materials is necessary. A phenomenological model for such behavior is given. The underlying principles are explained and some examples are given of the model's fit to actual measurements under simulated Earth-orbit conditions. Comments are given on the applicability of the model to materials testing and thermal modelling.
Model-based optical metrology and visualization of 3-D complex objects
LIU Xiao-li; LI A-meng; ZHAO Xiao-bo; GAO Peng-dong; TIAN Jin-dong; PENG Xiang
2007-01-01
This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and visualization of reconstructed 3D model by taking into account the shape measurement of 3D complex structures,and some experimental results are presented.
Zeng, Y.; Schaepman, M.E.; Wu, B.; Clevers, J.G.P.W.; Bregt, A.K.
2009-01-01
The physical-based geometric-optical Li-Strahler model can be inverted to retrieve forest canopy structural variables. One of the main input variables of the inverted model is the fractional component of sunlit background (K g). K g is calculated by using pure reflectance spectra (endmembers) of the
Optical and Acoustical Frequencies in a Nonlinear Helicoidal Model of DNA Molecules
ZDRAVKOVI(C) S.; SATARI(C) M.V.
2005-01-01
@@ We compare optical and acoustical frequencies in the Peyrard-Bishop-Dauxois model, i.e.an extended Peyrard-Bishop model, of DNA molecules.We discuss how ratio of those frequencies depends on a value of the harmonic constant of the helicoidal spring K.Also, we suggest that the most favourable mode could be a resonance mode.
Model independent optical potential for protons at 155 MeV
Brissaud, I.
1981-06-01
Using the model independent procedure, 155 MeV proton optical potentials are deduced from the elastic scattering data. The nuclear interior of these potentials are less attractative than predicted by a phenomenological potentials. A comparison is done with a self consistent meson model.
Scully, S.; Burke, D.; O'Sullivan, C.; Gayer, D.; Gradziel, M.; Murphy, J. A.; De Petris, M.; Buzi, D.; Zannoni, M.; Mennella, A.; Gervasi, M.; Tartari, A.; Maffei, B.; Aumont, J.; Banfi, S.; Battaglia, P.; Battistelli, E. S.; Baó, A.; Bélier, B.; Bennet, D.; Bergé, L.; Bernard, J.-Ph.; Bersanelli, M.; Bigot-Sazy, M.-A.; Bleurvacq, N.; Bordier, G.; Brossard, J.; Bunn, E. F.; Cammileri, D.; Cavaliere, F.; Chanial, P.; Chapron, C.; Coppolecchia, A.; Couchot, F.; D'Alessandro, G.; De Bernardis, P.; Decourcelle, T.; Del Torto, F.; Dumoulin, L.; Franceschet, C.; Gault, A.; Ghribi, A.; Giard, M.; Giraud-Héraud, Y.; Grandsire, L.; Hamilton, J. C.; Haynes, V.; Henrot-Versillé, S.; Holtzer, N.; Kaplan, J.; Korotkov, A.; Lande, J.; Lowitz, A.; Marnieros, S.; Martino, J.; Masi, S.; McCulloch, Mark; Melhuish, Simon; Montier, L.; Néel, D.; Ng, M. W.; Pajot, F.; Passerini, A.; Perbost, C.; Perdereau, O.; Piacentini, F.; Piat, M.; Piccirillo, L.; Pisano, G.; Prêle, D.; Puddu, R.; Rambaud, D.; Rigaut, O.; Salatino, M.; Schillaci, A.; Stolpovskiy, M.; Timbie, P.; Tristram, M.; Tucker, G.; Viganò, D.; Voisin, F.; Watson, B.
2016-07-01
Big Bang cosmologies predict that the cosmic microwave background (CMB) contains faint temperature and polarisation anisotropies imprinted in the early universe. ESA's PLANCK satellite has already measured the temperature anisotropies1 in exquisite detail; the next ambitious step is to map the primordial polarisation signatures which are several orders of magnitude lower. Polarisation E-modes have been measured2 but the even-fainter primordial B-modes have so far eluded detection. Their magnitude is unknown but it is clear that a sensitive telescope with exceptional control over systematic errors will be required. QUBIC3 is a ground-based European experiment that aims to exploit the novel concept of bolometric interferometry in order to measure B-mode polarisation anisotropies in the CMB. Beams from an aperture array of corrugated horns will be combined to form a synthesised image of the sky Stokes parameters on two focal planes: one at 150 GHz the other at 220 GHz. In this paper we describe recent optical modelling of the QUBIC beam combiner, concentrating on modelling the instrument point-spread-function and its operation in the 220-GHz band. We show the effects of optical aberrations and truncation as successive components are added to the beam path. In the case of QUBIC, the aberrations introduced by off-axis mirrors are the dominant contributor. As the frequency of operation is increased, the aperture horns allow up to five hybrid modes to propagate and we illustrate how the beam pattern changes across the 25% bandwidth. Finally we describe modifications to the QUBIC optical design to be used in a technical demonstrator, currently being manufactured for testing in 2016.
Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Aparin, A; Arkhipkin, D; Aschenauer, E C; Ashraf, M U; Attri, A; Averichev, G S; Bai, X; Bairathi, V; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandenburg, J D; Brandin, A V; Bunzarov, I; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Campbell, J M; Cebra, D; Chakaberia, I; Chaloupka, P; Chang, Z; Chatterjee, A; Chattopadhyay, S; Chen, X; Chen, J H; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, S; Gupta, A; Guryn, W; Hamad, A I; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Heppelmann, S; Hirsch, A; Hoffmann, G W; Horvat, S; Huang, T; Huang, B; Huang, X; Huang, H Z; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jentsch, A; Jia, J; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikoła, D P; Kisel, I; Kisiel, A; Kochenda, L; Koetke, D D; Kosarzewski, L K; Kraishan, A F; Kravtsov, P; Krueger, K; Kumar, L; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, X; Li, Y; Li, C; Li, W; Li, X; Lin, T; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Luo, S; Ma, G L; Ma, L; Ma, Y G; Ma, R; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Matis, H S; McDonald, D; McKinzie, S; Meehan, K; Mei, J C; Miller, Z W; Minaev, N G; Mioduszewski, S; Mishra, D; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Niida, T; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V A; Olvitt, D; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Pile, P; Pluta, J; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Pruthi, N K; Przybycien, M; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Ray, R L; Reed, R; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, A; Sharma, B; Sharma, M K; Shen, W Q; Shi, Z; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Singha, S; Skoby, M J; Smirnov, D; Smirnov, N; Solyst, W; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B; Sun, Y; Sun, Z; Sun, X M; Surrow, B; Svirida, D N; Tang, Z; Tang, A H; Tarnowsky, T; Tawfik, A; Thäder, J; Thomas, J H; Timmins, A R; Tlusty, D; Todoroki, T; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbæk, F; Vokal, S; Voloshin, S A; Vossen, A; Wang, H; Wang, F; Wang, Y; Wang, J S; Wang, G; Wang, Y; Webb, J C; Webb, G; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y; Xiao, Z G; Xie, W; Xie, G; Xin, K; Xu, N; Xu, Q H; Xu, Z; Xu, J; Xu, H; Xu, Y F; Yang, S; Yang, Y; Yang, C; Yang, Y; Yang, Y; Yang, Q; Ye, Z; Ye, Z; Yi, L; Yip, K; Yoo, I -K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, Z; Zhang, J B; Zhang, S; Zhang, S; Zhang, X P; Zhang, Y; Zhang, J; Zhang, J; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M
2016-01-01
The inclusive $J/\\psi$ transverse momentum ($p_{T}$) spectra and nuclear modification factors are reported at midrapidity ($|y|<1.0$) in Au+Au collisions at $\\sqrt{s_{NN}}=$ 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of $J/\\psi$ production, with respect to {\\color{black}the production in $p+p$ scaled by the number of binary nucleon-nucleon collisions}, is observed in central Au+Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct $J/\\psi$ production due to the color screening effect and $J/\\psi$ regeneration from recombination of uncorrelated charm-anticharm quark pairs.
Madland, D.G.; Young, P.G.
1978-10-01
An evaluation of the n + /sup 242/Pu cross sections is presented for the neutron energy range of 10 keV to 20 MeV. The total fission and radiative capture cross sections are based upon experimental measurements on /sup 242/Pu. The remaining cross sections, together with the elastic and inelastic angular distributions to low-lying states, were calculated using various reaction models. An expression is presented for the energy dependence of the average number of neutrons produced per fission. The results were placed in ENDF/B-V format and combined with a recent evaluation of data below 10 keV by the Hanford Engineering Development Laboratory, so that a complete data set covering the energy range of 10/sup -5/ eV to 20 MeV is available. 41 references. (JFP)
Energy dependence of J/ψ production in Au+Au collisions at sNN=39,62.4 and 200GeV
L. Adamczyk
2017-08-01
Full Text Available The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|<1.0 in Au+Au collisions at sNN = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J/ψ production, with respect to the production in p+p scaled by the number of binary nucleon–nucleon collisions, is observed in central Au+Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J/ψ production due to the color screening effect and J/ψ regeneration from recombination of uncorrelated charm–anticharm quark pairs.
NA49 Collaboration; Anticic, T.
2009-04-15
Results are presented on event-by-event fluctuations of transverse momenta p{sub T} in central Pb+Pb interactions at 20A, 30A, 40A, 80A, and 158A GeV. The analysis was performed for charged particles at forward center-of-mass rapidity (1.1 < y*{sub {pi}} < 2.6). Three fluctuation measures were studied: the distribution of average transverse momentum M(p{sub T}) in the event, the {phi}{sub p{sub T}} fluctuation measure, and two-particle transverse momentum correlations. Fluctuations of p{sub T} are small and show no significant energy dependence in the energy range of the CERN Super Proton Synchrotron. Results are compared with QCD-inspired predictions for the critical point, and with the UrQMD model. Transverse momentum fluctuations, similar to multiplicity fluctuations, do not show the increase expected for freeze-out near the critical point of QCD.
Remote sensing reflectance model of optically active components of turbid waters
Kutser, Tiit; Arst, Helgi
1994-12-01
A mathematical model that simulates the spectral curves of remote sensing reflectance is developed. The model is compared to measurements obtained from research vessel or boat in the Baltic Sea and Estonian lakes. The model simulates the effects of light backscattering from water and suspended matter, and the effects of its absorption due to water, phytoplankton, suspended matter and yellow substance. Measured by remote sensing spectral curves are compared by multiple of spectra obtained from model calculations to find the theoretical spectrum which is closest to experimental. It is assumed that in case of coincidence of the spectral curves concentrations of optically active substances in the model correspond to real ones. Preliminary testing of the model demonstrates that this model is useful for estimation of concentration of optically active substances in the waters of the Baltic Sea and Estonian lakes.
Modeling simulation of the thermal radiation for high-speed flight vehicles' aero-optical windows
Chen, Lei; Zhang, Liqin; Guo, Mingjiang
2015-10-01
When high-speed flight vehicles fly in the atmosphere, they can generate serious aero-optical effect. The optical window temperature rises sharply because of aerodynamic heating. It will form radiation interference that can lead infrared detectors to producing non-uniform radiation backgrounds, decreasing system SNR and detection range. Besides, there exits temperature difference due to uneven heating. Under the thermo-optical and elastic-optical effects, optical windows change into inhomogeneous mediums which influence the ray propagation. In this paper, a model of thermal radiation effect was built by a finite element analysis method. Firstly, the optical window was divided into uniform grids. Then, radiation distribution on the focal planes at different angles of the window's normal line and optical axis was obtained by tracing light rays of each grid. Finally, simulation results indicate that radiation distribution reflects the two directions-the length and width-of temperature distribution, and the change of angle causes the center of radiation distribution to shift to one direction of the image surface under the same window temperature.
Modeling the Stability of Topological Matter in Optical Lattices
2013-05-18
is of the same order as the Heisenberg coupling constant, J. (II) We study the phase diagram of the effective spin model using classical Monte Carlo ...I will construct and analyze a model using a combination of mean field theory and quantum Monte Carlo . The proposed work will foster new...construct and analyze a model using a com- bination of mean field theory and quantum Monte Carlo . The proposed work will foster new directions in
Gustafson, S. C.
1985-12-01
The technical contributions were as follows: (1) Optical parallel 2-D neighborhood processor and optical processor assessment technique; (2) High accuracy with moderately accurate components and optical fredkin gate architectures; (3) Integrated optical threshold computing, pipelined polynomial processor, and all optical analog/digital converter; (4) Adaptive optical associative memory model with attention; (5) Effectiveness of parallelism and connectivity in optical computers; (6) Optical systolic array processing using an integrated acoustooptic module; (7) Optical threshold elements and networks, holographic threshold processors, adaptive matched spatial filtering, and coherence theory in optical computing; (8) Time-varying optical processing for sub-pixel targets, optical Kalman filtering, and adaptive matched filtering; (9) Optical degrees of freedom, ultra short optical pulses, number representations, content-addressable-memory processors, and integrated optical Givens rotation devices; (10) Optical J-K flip flop analysis and interfacing for optical computers; (11) Matrix multiplication algorithms and limits of incoherent optical computers; (12) Architecture for machine vision with sensor fusion, pattern recognition functions, and neural net implementations; (13) Optical computing algorithms, architectures, and components; and (14) Dynamic optical interconnections, advantages and architectures.
Modelling and prediction of non-stationary optical turbulence behaviour
Doelman, Niek; Osborn, James
2016-07-01
There is a strong need to model the temporal fluctuations in turbulence parameters, for instance for scheduling, simulation and prediction purposes. This paper aims at modelling the dynamic behaviour of the turbulence coherence length r0, utilising measurement data from the Stereo-SCIDAR instrument installed at the Isaac Newton Telescope at La Palma. Based on an estimate of the power spectral density function, a low order stochastic model to capture the temporal variability of r0 is proposed. The impact of this type of stochastic model on the prediction of the coherence length behaviour is shown.
Simulation and experimental results of optical and thermal modeling of gold nanoshells
Ghazanfari, Lida; Khosroshahi, Mohammad E., E-mail: khosrom@mie.utoronto.ca
2014-09-01
This paper proposes a generalized method for optical and thermal modeling of synthesized magneto-optical nanoshells (MNSs) for biomedical applications. Superparamagnetic magnetite nanoparticles with diameter of 9.5 ± 1.4 nm are fabricated using co-precipitation method and subsequently covered by a thin layer of gold to obtain 15.8 ± 3.5 nm MNSs. In this paper, simulations and detailed analysis are carried out for different nanoshell geometry to achieve a maximum heat power. Structural, magnetic and optical properties of MNSs are assessed using vibrating sample magnetometer (VSM), X-ray diffraction (XRD), UV–VIS spectrophotometer, dynamic light scattering (DLS), and transmission electron microscope (TEM). Magnetic saturation of synthesized magnetite nanoparticles are reduced from 46.94 to 11.98 emu/g after coating with gold. The performance of the proposed optical–thermal modeling technique is verified by simulation and experimental results. - Highlights: • Proposing a generalized method for optical and thermal modeling of nanoshells • Verification of the proposed modeling technique by simulation and experimental results • Simulations for different nanoshell geometry to achieve a maximum heat power • Synthesis and characterization of magneto-optical nanoshells.
Leavesley, Silas; Bayraktar, Bülent; Venkatapathi, Murugesan; Hirleman, E. Dan; Bhunia, Arun K.; Robinson, J. Paul; Hassler, Richard; Smith, Linda; Rajwa, Bartek
2007-02-01
Traditional biological and chemical methods for pathogen identification require complicated sample preparation for reliable results. Optical scattering technology has been used for identification of bacterial cells in suspension, but with only limited success. Our published reports have demonstrated that scattered light based identification of Listeria colonies growing on solid surfaces is feasible with proper pattern recognition tools. Recently we have extended this technique to classification of other bacterial genera including, Salmonella, Bacillus, and Vibrio. Our approach may be highly applicable to early detection and classification of pathogens in food-processing industry and in healthcare. The unique scattering patterns formed by colonies of different species are created through differences in colony microstructure (on the order of wavelength used), bulk optical properties, and the macroscopic morphology. While it is difficult to model the effect on scatter-signal patterns owing to the microstructural changes, the influence of bulk optical properties and overall shape of colonies can be modeled using geometrical optics. Our latest research shows that it is possible to model the scatter pattern of bacterial colonies using solid-element optical modeling software (TracePro), and theoretically assess changes in macro structure and bulk refractive indices. This study allows predicting the theoretical limits of resolution and sensitivity of our detection and classification methods. Moreover, quantification of changes in macro morphology and bulk refractive index provides an opportunity to study the response of colonies to various reagents and antibiotics.
Dong, Erbao; Zhao, Zuhua; Wang, Minjie; Xie, Yanjun; Li, Shidi; Shao, Pengfei; Cheng, Liuquan; Xu, Ronald X.
2015-12-01
Biomedical optical devices are widely used for clinical detection of various tissue anomalies. However, optical measurements have limited accuracy and traceability, partially owing to the lack of effective calibration methods that simulate the actual tissue conditions. To facilitate standardized calibration and performance evaluation of medical optical devices, we develop a three-dimensional fuse deposition modeling (FDM) technique for freeform fabrication of tissue-simulating phantoms. The FDM system uses transparent gel wax as the base material, titanium dioxide (TiO2) powder as the scattering ingredient, and graphite powder as the absorption ingredient. The ingredients are preheated, mixed, and deposited at the designated ratios layer-by-layer to simulate tissue structural and optical heterogeneities. By printing the sections of human brain model based on magnetic resonance images, we demonstrate the capability for simulating tissue structural heterogeneities. By measuring optical properties of multilayered phantoms and comparing with numerical simulation, we demonstrate the feasibility for simulating tissue optical properties. By creating a rat head phantom with embedded vasculature, we demonstrate the potential for mimicking physiologic processes of a living system.
Modeling an Electrically Driven Graphene-Nanoribbon Laser for Optical Interconnects
Shan, Guangcun
2012-01-01
Graphene has two very important optical properties of population inversion of electrons, and broadband optical gain. As a result, graphene has potential for use in lasers and amplifiers. In this work, we presented a quantum master model and analyzed the properties for the electrically pumped single-AGNR vertical-cavity surface-emitting lasers (VCSELs) to investigate the lasing action and laser properties for realistic experimental parameters. A semiclassical approximation for the output power and laser linewidth is also derived. The laser threshold power was several orders of magnitude lower than that currently achievable with semiconductor microlasers. Our results have demonstrated that a single-AGNR VCSEL can serve as a nanolaser with ultralow lasing threshold. Implementation of such a GNR-based VCSEL is especially promising for optical interconnection systems since VCSELs emit low optical power and single longitudinal mode over a wide wavelength spectral range through tailoring GNRs.
Drude Weight,Optical Conductivity of Two-Dimensional Hubbard Model at Half Filling
XU Lei; ZHANG Jun
2008-01-01
We study the Drude weight D and optical conductivity of the two-dimensional (2D) Hubbard model at half filling with staggered magnetic flux (SMF).When SMF being introduced,the hopping integrals are modulated by the magnetic flux.The optical sum rule,which is related to the mean kinetic energy of band electrons,is evaluated for this 2D Hubbard Hamiltonian.Our present result gives the dependence of the kinetic energy,D and the optical conductivity on SMF and U.At half filling D vanishes exponentially with system size.We also find in the frequency dependence of the optical conductivity,there is &function peak at ω≈2|m|U and the incoherent excitations begin to present themselves extended to a higher energy region.
Propagation of Coherent Gaussian Schell-Model Beam Array in a Misaligned Optical System
ZHOU Pu; WANG Xiao-Lin; MA Yan-Xing; MA Hao-Tong; XU Xiao-Jun; LIU Ze-Jin
2011-01-01
@@ Based on a generalized Collins formula,the analytical formula for the propagation property of coherent Gaussian Schell-rnodel(GSM) beam array through a misaligned optical system is derived.As numerical examples,the propagation of a coherent GSM beam array in a typical misaligned optical system with a thin lens is evaluated.The influence of different misalignment parameters is calculated and the normalized-intensity distribution is graphically illustrated.%Based on a generalized Collins formula, the analytical formula for the propagation property of coherent Gaussian Schell-model (GSM) beam array through a misaligned optical system is derived. As numerical examples, the propagation of a coherent GSM beam array in a typical misaligned optical system with a thin lens is evaluated.The influence of different misalignment parameters is calculated and the normalized-intensity distribution is graphically illustrated.
Numerical Modeling of a Near-Field Scanning Optical System
Kann, Joshua Louis
A near-field scanning optical (NFO) system utilizes a subwavelength sized aperture to illuminate a sample. The aperture raster scans the sample. During the scan, the aperture is held in proximity to the sample. At each sampling point, the integrated far-zone energy distribution is stored. This collection of data is used to generate an image of the sample's surface. The main advantage of NFO systems is their very high spatial resolution. In this dissertation a hybrid finite-difference-time-domain (FDTD)/angular spectrum code is used to study the electromagnetic and imaging properties of a NFO scanning system. In addition, a finite-difference thermal (FD-thermal) code is used to calculate the thermal properties of a NFO system. Various aperture/sample geometries are studied numerically using both TE and TM polarization within a two-dimensional metallic waveguide that forms the aperture. The spatial properties of the electric field emitted by the aperture with no sample present are greatly influenced by the polarization. In particular, the electric field with TM polarization exhibits sharp peaks near the corners of the aperture, while the field with TE polarization is smooth and peaked at the center of the aperture. For both polarizations, the electric field remains collimated for a distance comparable to the aperture size. The electric field for both polarizations is altered when a dielectric sample is placed in proximity to the aperture. It is shown that the most representative image of the sample's topography is obtained using TE polarization and the resulting total far-zone energy as the sampled data. It is also shown that simpler scalar methods do not accurately predict the imaging behavior of a NFO system. Under certain circumstances the relationship between the sample's topography and the detected image is nearly linear. Under these conditions a system transfer function is calculated. Using the transfer function, it is shown that the spatial resolution of a NFO
Case study of modeled aerosol optical properties during the SAFARI 2000 campaign.
Kuzmanoski, Maja; Box, Michael A; Schmid, Beat; Russell, Philip B; Redemann, Jens
2007-08-01
We present modeled aerosol optical properties (single scattering albedo, asymmetry parameter, and lidar ratio) in two layers with different aerosol loadings and particle sizes, observed during the Southern African Regional Science Initiative 2,000 (SAFARI 2,000) campaign. The optical properties were calculated from aerosol size distributions retrieved from aerosol layer optical thickness spectra, measured using the NASA Ames airborne tracking 14-channel sunphotometer (AATS-14) and the refractive index based on the available information on aerosol chemical composition. The study focuses on sensitivity of modeled optical properties in the 0.3-1.5 microm wavelength range to assumptions regarding the mixing scenario. We considered two models for the mixture of absorbing and nonabsorbing aerosol components commonly used to model optical properties of biomass burning aerosol: a layered sphere with absorbing core and nonabsorbing shell and the Maxwell-Garnett effective medium model. In addition, comparisons of modeled optical properties with the measurements are discussed. We also estimated the radiative effect of the difference in aerosol absorption implied by the large difference between the single scattering albedo values (approximately 0.1 at midvisible wavelengths) obtained from different measurement methods for the case with a high amount of biomass burning particles. For that purpose, the volume fraction of black carbon was varied to obtain a range of single scattering albedo values (0.81-0.91 at lambda=0.50 microm). The difference in absorption resulted in a significant difference in the instantaneous radiative forcing at the surface and the top of the atmosphere (TOA) and can result in a change of the sign of the aerosol forcing at TOA from negative to positive.
Alliss, R.; Felton, B.
Optical turbulence (OT) acts to distort light in the atmosphere, degrading imagery from large astronomical telescopes and possibly reducing data quality of air to air laser communication links. Some of the degradation due to turbulence can be corrected by adaptive optics. However, the severity of optical turbulence, and thus the amount of correction required, is largely dependent upon the turbulence at the location of interest. Therefore, it is vital to understand the climatology of optical turbulence at such locations. In many cases, it is impractical and expensive to setup instrumentation to characterize the climatology of OT, so simulations become a less expensive and convenient alternative. The strength of OT is characterized by the refractive index structure function Cn2, which in turn is used to calculate atmospheric seeing parameters. While attempts have been made to characterize Cn2 using empirical models, Cn2 can be calculated more directly from Numerical Weather Prediction (NWP) simulations using pressure, temperature, thermal stability, vertical wind shear, turbulent Prandtl number, and turbulence kinetic energy (TKE). In this work we use the Weather Research and Forecast (WRF) NWP model to generate Cn2 climatologies in the planetary boundary layer and free atmosphere, allowing for both point-to-point and ground-to-space seeing estimates of the Fried Coherence length (ro) and other seeing parameters. Simulations are performed using the Maui High Performance Computing Centers Jaws cluster. The WRF model is configured to run at 1km horizontal resolution over a domain covering the islands of Maui and the Big Island. The vertical resolution varies from 25 meters in the boundary layer to 500 meters in the stratosphere. The model top is 20 km. We are interested in the variations in Cn2 and the Fried Coherence Length (ro) between the summits of Haleakala and Mauna Loa. Over six months of simulations have been performed over this area. Simulations indicate that
Perera, M. Nilusha M. N.; Schmidt, Daniel; Gibbs, W. E. Keith; Juodkazis, Saulius; Stoddart, Paul R.
2016-09-01
Surface-enhanced Raman scattering (SERS) is drawing increasing interest in fields such as chemical and biomolecular sensing, nanoscale plasmonic engineering and surface science. In addition to the electromagnetic and chemical enhancements in SERS, several studies have reported a "back-side" enhancement when nanostructures are excited through a transparent base rather than directly through air. This additional enhancement has been attributed to a local increase in the electric field for propagation from high to low refractive index media. In this study, Mueller matrix ellipsometry was used to derive the effective optical constants of Ag nanostructures fabricated by thermal evaporation at oblique angles. The results confirm that the effective optical constants of the nanostructured Ag film depart substantially from the bulk properties. Detailed analysis suggests that the optical constants of the nano-island Ag structures exhibit uniaxial optical properties with the optical axis inclined from the substrate normal towards the deposition direction of the vapour flux. The substrates were functionalized with thiophenol and used to measure the wavelength dependence of the additional SERS signal. Further, a model based on the Fresnel equations was developed, using the Ag film optical constants and thickness as determined by ellipsometry. Both experimental data and the model show a significant additional enhancement in the back-side SERS, blue shifted from the plasmon resonance of the nanostructures. This information will be useful for a range of applications where it is necessary to understand the effective optical behaviour of thin films and in designing miniaturized optical fibre sensors for remote sensing applications.
An optical flow-based state-space model of the vocal folds
Granados, Alba; Brunskog, Jonas
2017-01-01
. A linear and Gaussian nonstationary state-space model is proposed and thoroughly discussed. The evolution model is based on a self-sustained three-dimensional finite element model of the vocal folds, and the observation model involves a dense optical flow algorithm. The results show that the method is able......High-speed movies of the vocal fold vibration are valuable data to reveal vocal fold features for voice pathology diagnosis. This work presents a suitable Bayesian model and a purely theoretical discussion for further development of a framework for continuum biomechanical features estimation...... to capture different deformation patterns between the computed optical flow and the finite element deformation, controlled by the choice of the model tissue parameters....
Modelling and Observation of Mineral Dust Optical Properties over Central Europe
Chilinski, Michał T.; Markowicz, Krzysztof M.; Zawadzka, Olga; Stachlewska, Iwona S.; Kumala, Wojciech; Petelski, Tomasz; Makuch, Przemysław; Westphal, Douglas L.; Zagajewski, Bogdan
2016-12-01
This paper is focused on Saharan dust transport to Central Europe/Poland; we compare properties of atmospheric Saharan dust using data from NAAPS, MACC, AERONET as well as observations obtained during HyMountEcos campaign in June 2012. Ten years of dust climatology shows that long-range transport of Saharan dust to Central Europe is mostly during spring and summer. HYSPLIT back-trajectories indicate airmass transport mainly in November, but it does not agree with modeled maxima of dust optical depth. NAAPS model shows maximum of dust optical depth ( 0.04-0.05, 550 nm) in April-May, but the MACC modeled peak is broader ( 0.04). During occurrence of mineral dust over Central-Europe for 14% (NAAPS) / 12% (MACC) of days dust optical depths are above 0.05 and during 4% (NAAPS) / 2.5% (MACC) of days dust optical depths exceed 0.1. The HyMountEcos campaign took place in June-July 2012 in the mountainous region of Karkonosze. The analysis includes remote sensing data from lidars, sun-photometers, and numerical simulations from NAAPS, MACC, DREAM8b models. Comparison of simulations with observations demonstrates the ability of models to reasonably reproduce aerosol vertical distributions and their temporal variability. However, significant differences between simulated and measured AODs were found. The best agreement was achieved for MACC model.
Modelling and Observation of Mineral Dust Optical Properties over Central Europe
Chilinski Michał T.
2016-12-01
Full Text Available This paper is focused on Saharan dust transport to Central Europe/Poland; we compare properties of atmospheric Saharan dust using data from NAAPS, MACC, AERONET as well as observations obtained during HyMountEcos campaign in June 2012. Ten years of dust climatology shows that long-range transport of Saharan dust to Central Europe is mostly during spring and summer. HYSPLIT back-trajectories indicate airmass transport mainly in November, but it does not agree with modeled maxima of dust optical depth. NAAPS model shows maximum of dust optical depth (~0.04-0.05, 550 nm in April-May, but the MACC modeled peak is broader (~0.04. During occurrence of mineral dust over Central-Europe for 14% (NAAPS / 12% (MACC of days dust optical depths are above 0.05 and during 4% (NAAPS / 2.5% (MACC of days dust optical depths exceed 0.1. The HyMountEcos campaign took place in June-July 2012 in the mountainous region of Karkonosze. The analysis includes remote sensing data from lidars, sun-photometers, and numerical simulations from NAAPS, MACC, DREAM8b models. Comparison of simulations with observations demonstrates the ability of models to reasonably reproduce aerosol vertical distributions and their temporal variability. However, significant differences between simulated and measured AODs were found. The best agreement was achieved for MACC model.
Meneses, Domingos De Sousa; Rousseau, Benoit; Echegut, Patrick; Matzen, Guy
2007-06-01
A new expression of dielectric function model based on piecewise polynomials is introduced. Its association with spline and more recent shape preserving interpolation algorithms allows easy reproduction of every kind of experimental spectra and thus retrieval of all the linear optical functions of a material. Based on a pure mathematical framework, the expression of the model is always applicable and does not necessitate any knowledge of the microscopic mechanisms of absorption responsible for the optical response. The potential of piecewise polynomial dielectric functions is shown through synthetic examples and the analysis of experimental spectra.
Analogical optical modeling of the asymmetric lateral coherence of betatron radiation.
Paroli, B; Chiadroni, E; Ferrario, M; Potenza, M A C
2015-11-16
By exploiting analogical optical modeling of the radiation emitted by ultrarelativistic electrons undergoing betatron oscillations, we demonstrate peculiar properties of the spatial coherence through an interferometric method reminiscent of the classical Young's double slit experiment. The expected effects due to the curved trajectory and the broadband emission are accurately reproduced. We show that by properly scaling the fundamental parameters for the wavelength, analogical optical modeling of betatron emission can be realized in many cases of broad interest. Applications to study the feasibility of future experiments and to the characterization of beam diagnostics tools are described.
Different models of gravitating Dirac fermions in optical lattices
Celi, Alessio
2017-07-01
In this paper I construct the naive lattice Dirac Hamiltonian describing the propagation of fermions in a generic 2D optical metric for different lattice and flux-lattice geometries. First, I apply a top-down constructive approach that we first proposed in [Boada et al., New J. Phys. 13, 035002 (2011)] to the honeycomb and to the brickwall lattices. I carefully discuss how gauge transformations that generalize momentum (and Dirac cone) shifts in the Brillouin zone in the Minkowski homogeneous case can be used in order to change the phases of the hopping. In particular, I show that lattice Dirac Hamiltonian for Rindler spacetime in the honeycomb and brickwall lattices can be realized by considering real and isotropic (but properly position dependent) tunneling terms. For completeness, I also discuss a suitable formulation of Rindler Dirac Hamiltonian in semi-synthetic brickwall and π-flux square lattices (where one of the dimension is implemented by using internal spin states of atoms as we originally proposed in [Boada et al., Phys. Rev. Lett. 108, 133001 (2012)] and [Celi et al., Phys. Rev. Lett. 112, 043001 (2014)]).
Angular and energy dependence of ion bombardment of Mo/Si multilayers
Voorma, H.J.; Louis, E.; Bijkerk, F.;
1997-01-01
The process of ion bombardment is investigated for the fabrication of Mo/Si multilayer x-ray mirrors using e-beam evaporation. The ion treatment is applied immediately after deposition of each of the Si layers to smoothen the layers by removing an additional thickness of the Si layer. In this study...... the parameters of Kr+ ion bombardment have been optimized within the energy range 300 eV-2 keV and an angular range between 20 degrees and 50 degrees. The optical performance of the Mo/Si multilayers is determined by absolute measurements of the near-normal-incidence reflectivity at 14.4 nm wavelength...... are found to be 2 keV at 50 degrees angle of incidence with respect to the surface. These settings result in 47% reflectivity at 85 degrees (lambda = 14.4 nm) for a 16-period Mo/Si multilayer mirror, corresponding to an interface roughness of 0.21 nm rms. Analysis shows that the interface roughness...
Nishi, R; Yoshida, K; Takaoka, A; Katsuta, T
1996-03-01
The characteristics of fluorescent plates for high energy electron beams (0.5-2.0 MeV) are examined. The thickness and the optical transparency of plates strongly affect the luminous broadening and intensity. The spatial luminous broadening in fluorescent plates is measured and is simply represented by the rise width of a knife edge image. When the thickness is much smaller than the range of incident electrons, the rise width is 1/4-1/5 of the thickness in the case of YAG single crystal plates that are transparent for light, while the rise width is nearly equal to the thickness for the packed P22 powder plates that are opaque for light. To suppress the luminous broadening under 50 microm, the thickness of YAG plates has to be thinner than 250 microm in the energy region around 2 MeV. Under the same condition of the rise width, the luminous intensity of YAG plates is twice as high as that of the P22 plates.
An overlooked riddle of life's origins: energy-dependent nucleic acid unzipping.
Kovác, Ladislav; Nosek, Jozef; Tomáska, L'ubomír
2003-01-01
The imposing progress in understanding contemporary life forms on Earth and in manipulating them has not been matched by a comparable progress in understanding the origins of life. This paper argues that a crucial problem of unzipping of the double helix molecule of nucleic acid during its replication has been underrated, if not plainly overlooked, in the theories of life's origin and evolution. A model is presented of how evolution may have solved the problem in its early phase. Similar to several previous models, the model envisages the existence of a protocell, in which osmotic disbalance is being created by accumulation of synthetic products resulting in expansion and division of the protocell. Novel in the model is the presence in the protocell of a double-stranded nucleic acid, with each of its two strands being affixed by its 3'-terminus to the opposite sides of the membrane of a protocell. In the course of the protocell expansion, osmotic force is utilized to pull the two strands longitudinally in opposite directions, unzipping the helix and partitioning the strands between the two daughter protocells. The model is also being used as a background for arguments of why life need operate in cycles. Many formal models of life's origin and evolution have not taken into account the fact that logical possibility does not equal thermodynamic feasibility. A system of self-replication has to consist of both replicators and replicants.
Optical spectroscopic studies of animal skin used in modeling of human cutaneous tissue
Drakaki, E.; Makropoulou, M.; Serafetinides, A. A.; Borisova, E.; Avramov, L.; Sianoudis, J. A.
2007-03-01
Optical spectroscopy and in particular laser-induced autofluorescence spectroscopy (LIAFS) and diffuse reflectance spectroscopy (DRS), provide excellent possibilities for real-time, noninvasive diagnosis of different skin tissue pathologies. However, the introduction of optical spectroscopy in routine medical practice demands a statistically important data collection, independent from the laser sources and detectors used. The scientists collect databases either from patients, in vivo, or they study different animal models to obtain objective information for the optical properties of various types of normal and diseased tissue. In the present work, the optical properties (fluorescence and reflectance) of two animal skin models are investigated. The aim of using animal models in optical spectroscopy investigations is to examine the statistics of the light induced effects firstly on animals, before any extrapolation effort to humans. A nitrogen laser (λ=337.1 nm) was used as an excitation source for the autofluorescence measurements, while a tungsten-halogen lamp was used for the reflectance measurements. Samples of chicken and pig skin were measured in vitro and were compared with results obtained from measurements of normal human skin in vivo. The specific features of the measured reflectance and fluorescence spectra are discussed, while the limits of data extrapolation for each skin type are also depicted.
Corrado Caudek
Full Text Available We measured perceived depth from the optic flow (a when showing a stationary physical or virtual object to observers who moved their head at a normal or slower speed, and (b when simulating the same optic flow on a computer and presenting it to stationary observers. Our results show that perceived surface slant is systematically distorted, for both the active and the passive viewing of physical or virtual surfaces. These distortions are modulated by head translation speed, with perceived slant increasing directly with the local velocity gradient of the optic flow. This empirical result allows us to determine the relative merits of two alternative approaches aimed at explaining perceived surface slant in active vision: an "inverse optics" model that takes head motion information into account, and a probabilistic model that ignores extra-retinal signals. We compare these two approaches within the framework of the bayesian theory. The "inverse optics" bayesian model produces veridical slant estimates if the optic flow and the head translation velocity are measured with no error; because of the influence of a "prior" for flatness, the slant estimates become systematically biased as the measurement errors increase. The bayesian model, which ignores the observer's motion, always produces distorted estimates of surface slant. Interestingly, the predictions of this second model, not those of the first one, are consistent with our empirical findings. The present results suggest that (a in active vision perceived surface slant may be the product of probabilistic processes which do not guarantee the correct solution, and (b extra-retinal signals may be mainly used for a better measurement of retinal information.
MILES extended: Stellar population synthesis models from the optical to the infrared
Röck, B.; Vazdekis, A.; Ricciardelli, E.; Peletier, R. F.; Knapen, J. H.; Falcón-Barroso, J.
2016-05-01
We present the first single-burst stellar population models, which covers the optical and the infrared wavelength range between 3500 and 50 000 Å and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical with our new infrared models that are based on the IRTF (Infrared Telescope Facility) library. The latter are available only for a limited range in terms of both age and metallicity. Our combined single-burst stellar population models were calculated for ages larger than 1 Gyr, for metallicities between [ Fe / H ] = - 0.40 and 0.26, for initial mass functions of various types and slopes, and on the basis of two different sets of isochrones. They are available to the scientific community on the MILES web page. We checked the internal consistency of our models and compared their colour predictions to those of other models that are available in the literature. Optical and near infrared colours that are measured from our models are found to reproduce the colours well that were observed for various samples of early-type galaxies. Our models will enable a detailed analysis of the stellar populations of observed galaxies.
REFINED MODEL OF THE OPTICAL SYSTEM FOR SPACE MINI-VEHICLES WITH LASER PROPULSION
M. S. Egorov
2015-09-01
Full Text Available Simulation results for on-board optical system of a space mini-vehicle with laser propulsion are presented. This system gives the possibility for receiving theremote laser radiation power independently of a system telescope mutual orientation to the vehicle orbiting direction. The on-board optical system is designed with the use of such optical elements as optical hinges and turrets. The system incorporates the optical switch that is a special optical system adapting optically both receiving telescope and laser propulsion engines. Modeling and numerical simulation of the system have been performed with the use of ZEMAX software (Radiant Ltd. The object matter of calculations lied in size definition of system optical elements, requirements to accuracy of their manufacturing and reciprocal adjusting to achieve an efficient radiation energy delivery to laser propulsion engine. Calculations have been performed with account to the limitations on the mini-vehicle mass, its overall dimensions, and radiation threshold density of the optical elements utilized. The requirements to the laser beam quality at the entrance aperture of laser propulsion engine have been considered too. State-of-the-art optical technologies make it possible to manufacture space reflectors made of CO-115M glassceramics with weight-reducing coefficient of 0.72 and the radiation threshold of 5 J/cm2 for the radiation with a 1.064 microns wavelength at 10-20 ns pulse duration. The optimal diameter of a receiving telescope primary mirror has been 0.5 m when a coordinated transmitting telescope diameter is equal to 1 m. This provides the reception of at least 84% of laser energy. The main losses of radiation energy are caused by improper installation of receiving telescope mirrors and by in-process errors arising at manufacturing the telescope mirrors with a parabolic surface. It is shown that requirements to the in-process admissible errors for the on-board optical system elements
Moro, Erik A [Los Alamos National Laboratory; Puckett, Anthony D [Los Alamos National Laboratory; Todd, Michael D [UCSD
2011-01-24
The intensity distribution of a transmission from a single mode optical fiber is often approximated using a Gaussian-shaped curve. While this approximation is useful for some applications such as fiber alignment, it does not accurately describe transmission behavior off the axis of propagation. In this paper, another model is presented, which describes the intensity distribution of the transmission from a single mode optical fiber. A simple experimental setup is used to verify the model's accuracy, and agreement between model and experiment is established both on and off the axis of propagation. Displacement sensor designs based on the extrinsic optical lever architecture are presented. The behavior of the transmission off the axis of propagation dictates the performance of sensor architectures where large lateral offsets (25-1500 {micro}m) exist between transmitting and receiving fibers. The practical implications of modeling accuracy over this lateral offset region are discussed as they relate to the development of high-performance intensity modulated optical displacement sensors. In particular, the sensitivity, linearity, resolution, and displacement range of a sensor are functions of the relative positioning of the sensor's transmitting and receiving fibers. Sensor architectures with high combinations of sensitivity and displacement range are discussed. It is concluded that the utility of the accurate model is in its predicative capability and that this research could lead to an improved methodology for high-performance sensor design.
Experience at Los Alamos with use of the optical model for applied nuclear data calculations
Young, P.G.
1994-10-01
While many nuclear models are important in calculations of nuclear data, the optical model usually provides the basic underpinning of analyses directed at data for applications. An overview is given here of experience in the Nuclear Theory and Applications Group at Los Alamos National Laboratory in the use of the optical model for calculations of nuclear cross section data for applied purposes. We consider the direct utilization of total, elastic, and reaction cross sections for neutrons, protons, deuterons, tritons, {sup 3}He and alpha particles in files of evaluated nuclear data covering the energy range of 0 to 200 MeV, as well as transmission coefficients for reaction theory calculations and neutron and proton wave functions direct-reaction and Feshbach-Kerman-Koonin analyses. Optical model codes such as SCAT and ECIS and the reaction theory codes COMNUC, GNASH FKK-GNASH, and DWUCK have primarily been used in our analyses. A summary of optical model parameterizations from past analyses at Los Alamos will be given, including detailed tabulations of the parameters for a selection of nuclei.
The energy dependence of the diffraction minimum and new LHC data
Selyugin, O V
2016-01-01
The soft diffraction phenomena in the elastic proton-proton scattering are reviewed from the viewpoint of experiments at the LHC (TOTEM and ATLAS collaboration). In the framework of the High Energy Generalized Structure (HEGS) model the form of the diffraction minimum in the nucleon-nucleon elastic scattering in a wide energy region is analyzed. The numerical predictions at LHC energies are presented. The comparison of the model predictions with the new LHC data at $\\sqrt{s}=13$ TeV is made.
Thermodynamic Modeling and Analysis of an Optical Electric-Field Sensor
Xia Xiao
2015-03-01
Full Text Available The stability of the optical electric field sensor (OEFS in actual operation is affected by environmental factors such as temperature and SF6 (sulfur hexafluoride. To analyze the operational environment parameters affecting the optical properties of crystals, a thermodynamic model of the OEFS in which the optical properties of the crystal are changed by the first-order effects and the second-order effects was established. The intensity parameters such as electric, stress and temperature fields were introduced. The theoretical analysis results show that under temperature, stress and electric field conditions, the optical properties of the sensing crystals are no longer changed only by the electro-optic effect, but also by the temperature and the stress fields. Further synthesis suggests the expected optical property changes under the effect of the environment fields. OEFS tests show that the accuracy of OEFS is dependent on temperature with a ratio error of −0.8%~1.5% in the temperature range from −25 °C to +40 °C.
Teaching Algebra and Geometry Concepts by Modeling Telescope Optics
Siegel, Lauren M.; Dickinson, Gail; Hooper, Eric J.; Daniels, Mark
2008-01-01
This article describes preparation and delivery of high school mathematics lessons that integrate mathematics and astronomy through The Geometer's Sketchpad models, traditional proof, and inquiry-based activities. The lessons were created by a University of Texas UTeach preservice teacher as part of a project-based field experience in which high…
Information Model for Connection Management in Automatic Switched Optical Network
Xu Yunbin(徐云斌); Song Hongsheng; Gui Xuan; Zhang Jie; Gu Wanyi
2004-01-01
The three types of connections (Permanent Connection, Soft Permanent Connection and Switched Connection) provided by ASON can adapt the requirement of different network services. Management and maintenance of these three connections are the most important aspect of ASON management. The information models proposed in this paper are used for the purpose of ASON connection management. Firstly a new information model is proposed to meet the requirement for the control plane introduced by ASON. In this model, a new class ControlNE is given, and the relationship between the ControlNE and the transport NE (network element) is also defined. Then this paper proposes information models for the three types of connections for the first time, and analyzes the relationship between the three kinds of connections and the basic network transport entities. Finally, the paper defines some CORBA interfaces for the management of the three connections. In these interfaces, some operations such as create or release a connection are defined, and some other operations can manage the performance of the three kinds of connections, which is necessary for a distributed management system.
Modelling a singly resonant, intracavity ring optical parametric oscillator
Buchhave, Preben; Tidemand-Lichtenberg, Peter; Wei, Hou;
2003-01-01
We study theoretically and experimentally the dynamics of a single-frequency, unidirectional ring laser with an intracavity nonlinear singly resonant OPO-crystal in a coupled resonator. We find for a range of operating conditions good agreement between model results and measurements of the laser ...
Optical Test of Local Hidden-Variable Model
WU XiaoHua; ZONG HongShi; PANG HouRong
2001-01-01
An inequality is deduced from local realism and a supplementary assumption. This inequality defines an experiment that can be actually performed with the present technology to test local hidden-variable models, and it is violated by quantum mechanics with a factor 1.92, while it can be simplified into a form where just two measurements are required.``
MILES extended: Stellar population synthesis models from the optical to the infrared
Röck, B; Ricciardelli, E; Peletier, R F; Knapen, J H; Falcon-Barroso, J
2016-01-01
We present the first single-burst stellar population models which covers the optical and the infrared wavelength range between 3500 and 50000 Angstrom and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical with our new infrared models that are based on the IRTF (Infrared Telescope Facility) library. The latter are available only for a limited range in terms of both age and metallicity. Our combined single-burst stellar population models were calculated for ages larger than 1 Gyr, for metallicities between [Fe/H] = -0.40 and 0.26, for initial mass functions of various types and slopes, and on the basis of two different sets of isochrones. They are available to the scientific community on the MILES web page. We checked the internal consistency of our models and compared their colour predictions to those of other models that are available in the literature. Optical and near infrared colours that are measured from our models...
Energy dependence of collective flow of neutrons and protons in [sup 197]Au + [sup 197]Au collisions
Lambrecht, D.; Blaich, T.; Elze, T.W.; Emling, H.; Freiesleben, H.; Grimni, K.; Henning, W.; Holzmann, R.; Keller, J.G.; Klingler, H.; Kratz, J.V.; Kulessa, R.; Lange, S.; Leifels, Y.; Lubkiewicz, E.; Moore, E.F.; Prokopowicz, W.; Schmidt, R.; Schuetter, C.; Spies, H.; Stelzer, K.; Stroth, J.; Wajda, E.; Walus, W.; Zinser, M.; Zude, E.; Alard, J.P.; Basrak, Z.; Bastid, N.; Belayev, I.M.; Bini, M.; Bock, R.; Buta, A.; Caplar, R.; Cerruti, C.; Cindro, N.; Coffin, J.P.; Crouau, M.; Dupieux, P.; Eroe, J.; Fan, Z.G.; Fintz, P.; Fodor, Z.; Freifelder, R.; Fraysse, L.; Frolov, S.; Gobbi, A.; Grigorian, Y.; Guillaume, G.; Herrmann, N.; Hildenbrand, K.D.; Hoelbling, S.; Houari, O.; Jeong, S.C.; Jorio, M.; Jundt, F.; Kecskemeti, J.; Koncz, P.; Korchagin, Y.; Kotte, R.; Kraemer, M.; Kuhn, C.; Legrand, I.; Lebedev, A.; Maguire, C.; Manko, V.; Matulewicz, T.; Mgebrishvili, G.; Moesner, J.; Moisa, D.; Montarou, G.; Morel, P.; Neubert, W.; Olmi, A.; Pasquali, G.; Pelte, D.; Petrovici, M.; Poggi, G.; FOPI-collaboration
1994-11-01
We investigate the beam energy dependence of neutron and proton squeeze-out in collisions of [sup 197]Au + [sup 197]Au at E/A=400-800 MeV. The azimuthal anisotropy that describes the enhanced emission of mid-rapidity neutrons perpendicular to the reaction plane rises strongly with the transverse momentum of the neutrons. This dependence of the azimuthal anisotropy follows a universal curve - independent of beam energy - if the neutron momenta are measured in fractions of the projectile momentum per mass unit. Analogously, the kinetic energy spectra of mid-rapidity neutrons exhibit a universal behaviour as a function of the kinetic energy of the projectile. (orig.)
Energy dependence of elliptic flow over a large pseudorapidity range in Au+Au collisions at RHIC
Back, B B; Ballintijn, M; Barton, D S; Betts, R R; Bickley, A A; Bindel, R; Budzanowski, A; Busza, W; Carroll, A; Chai, Z; Decowski, M P; García, E; Gburek, T; George, N; Gulbrandsen, K H; Gushue, S; Halliwell, C; Hamblen, J; Hauer, M; Heintzelman, G A; Henderson, C; Hofman, D J; Hollis, R S; Holynski, R; Holzman, B; Iordanova, A; Johnson, E; Kane, J L; Katzy, J; Khan, N; Kucewicz, W; Kulinich, P; Kuo, C M; Lin, W T; Manly, S; McLeod, D; Mignerey, A C; Nouicer, R; Olszewski, A; Pak, R; Park, I C; Pernegger, H; Reed, C; Remsberg, L P; Reuter, M; Roland, C; Roland, G; Rosenberg, L J; Sagerer, J; Sarin, P; Sawicki, P; Seals, H; Sedykh, I; Skulski, W; Smith, C E; Stankiewicz, M A; Steinberg, P; Stephans, G S F; Sukhanov, A; Tang, J L; Tonjes, M B; Trzupek, A; Vale, C; van Nieuwenhuizen, G J; Vaurynovich, S S; Verdier, R; Veres, G I; Wenger, E; Wolfs, F L H; Wosiek, B; Wozniak, K; Wuosmaa, A H; Wyslouch, B
2004-01-01
This paper describes the measurement of the energy dependence of elliptic flow for charged particles in Au+Au collisions using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). Data taken at collision energies of $\\sqrt{s_{_{NN}}} =$ 19.6, 62.4, 130 and 200 GeV are shown over a wide range in pseudorapidity. These results, when plotted as a function of $\\eta'=|\\eta|-y_{beam}$, scale with approximate linearity throughout $\\eta'$, implying no sharp changes in the dynamics of particle production as a function of pseudorapidity or increasing beam energy.
Incident energy dependence of dileption production in an expanding baryon—rich quark—gluon fireball
HeZe－Jun; ZhangJia－Ju; 等
1998-01-01
From the full stopping scenario,the dilepton production in the baryon-rich quark-gluon fireball based on a relativistic hydrodynamic model is studied.,and it is found that with increasing incident energy a characteristic plateau indicating the formation of the baryon-rich quark-gluon matter appears in the total yield.
On elastic proton-proton diffraction scattering and its energy dependence
Henzi, R
1979-01-01
Recent FNAL and CERN ISR data on proton-proton elastic scattering and total cross sections at momenta q/sub L/=200-2000 GeV/c and momentum transfers up to mod t mod =14 (GeV/c)/sup 2/ are discussed in terms of a short range expansion (SRE) of the inelastic overlap function (IOF). Model independence of the conclusions is established, which are also shown to be unaffected by real part and spin effects. (25 refs).
Optical modeling of nickel-base alloys oxidized in pressurized water reactor
Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)
2012-10-01
The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.
Simple method of modelling of digital holograms registering and their optical reconstruction
Evtikhiev, N. N.; Cheremkhin, P. A.; Krasnov, V. V.; Kurbatova, E. A.; Molodtsov, D. Yu; Porshneva, L. A.; Rodin, V. G.
2016-08-01
The technique of modeling of digital hologram recording and image optical reconstruction from these holograms is described. The method takes into account characteristics of the object, digital camera's photosensor and spatial light modulator used for digital holograms displaying. Using the technique, equipment can be chosen for experiments for obtaining good reconstruction quality and/or holograms diffraction efficiency. Numerical experiments were conducted.
Jurado-Navas, Antonio
2015-01-01
Recently, a new and generalized statistical model, called Málaga or simply M distribution, has been proposed to characterize the irradiance fluctuations of an unbounded optical wavefront (plane and spherical waves) propagating through a turbulent medium under all irradiance fluctuation conditions...
Neutron-energy-dependent defect production cross sections for fission and fusion applications
Odette, G.R.; Doiron, D.R.
1976-06-01
Neutron cross sections for displacements and post-short-term cascade annealing defects are derived from nuclear kinematics calculations of primary atomic recoil energy distributions and the number of secondary defects produced per primary as a function of recoil energy. For the first time, recoil kinematics of charged- and multiple-particle emission reactions are treated rigorously using a compound-nucleus evaporation spectrum nuclear model. Secondary-defect production functions, derived from computer simulation experiments, are taken from the literature. Spectral-averaged defect production cross sections for a fusion reactor first-wall-type environment are on the order of 1.5 to 2.5 times those for a fast fission reactor core-type spectrum. The indicated range of uncertainty is primarily due to secondary-defect production model sensitivity. Nuclear model and data errors are expected to become more significant at high neutron energies, greater than approximately 20 MeV. Fusion reactor environments are found to produce some very energetic recoils and high-energy release events due to charged-particle reactions such as (n,..cap alpha..).
A semitransparency-based optical-flow method with a point trajectory model for particle-like video.
Sakaino, Hidetomo
2012-02-01
This paper proposes a new semitransparency-based optical-flow model with a point trajectory (PT) model for particle-like video. Previous optical-flow models have used ranging from image brightness constancy to image brightness change models as constraints. However, two important issues remain unsolved. The first is how to track/match a semitransparent object with a very large displacement between frames. Such moving objects with different shapes and sizes in an outdoor scene move against a complicated background. Second, due to semitransparency, the image intensity between frames can also violate a previous image brightness-based optical-flow model. Thus, we propose a two-step optimization for the optical-flow estimation model for a moving semitransparent object, i.e., particle. In the first step, a rough optical flow between particles is estimated by a new alpha constancy constraint that is based on an image generation model of semitransparency. In the second step, the optical flow of a particle with a continuous trajectory in a definite temporal interval based on a PT model can be refined. Many experiments using various falling-snow and foggy scenes with multiple moving vehicles show the significant improvement of the optical flow compared with a previous optical-flow model.
Gokul, Elamurugu Alias; Shanmugam, Palanisamy; Sundarabalan, Balasubramanian; Sahay, Arvind; Chauhan, Prakash
2014-08-01
Retrieval of the inherent optical properties and estimation of the constituents' concentrations from satellite ocean colour data in turbid and eutrophic waters are important as these products provide innovative opportunities for the study of biological and biogeochemical properties in such optically complex waters. This paper intends to develop models to retrieve absorption coefficients of phytoplankton, suspended sediments and coloured dissolved organic matter and describe vertical profiles of chlorophyll and suspended sediments from satellite ocean colour data. These models make use of the relationships between remote sensing reflectance ratios Rrs (555)/Rrs (443) and Rrs (620)/Rrs (490) versus aph (443) and aph (555), and acdom (443), and ad (443) to derive the model parameters. Validation with the in-situ data obtained from coastal waters around India and other regional waters (e.g., NASA bio-Optical Marine Algorithm Data-Set, NOMAD) shows that the new models are more accurate in terms of producing the spectral absorption coefficients (aph, ad, acdom across the entire visible wavelengths 400-700 nm) in a wide variety of waters. Further comparison with existing models shows advantage of the new models that have important implications for remote sensing of turbid coastal and eutrophic waters. The retrieved absorption coefficients of phytoplankton and suspended sediments (non-algal matter) are also found to relate better to chlorophyll and total suspended sediments. Taking advantages of this, we derive models to determine and describe the vertical profiles of chlorophyll and suspended sediment concentrations along the depth. The model parameters are derived empirically. These new parameterizations show potential in estimating the vertical profiles of chlorophyll and suspended sediments with good accuracy. These results suggest robustness and suitability of the new models for studying the ecologically important components of optically complex turbid and eutrophic
Optical bandgap modeling of thermal annealed ZnO:Ga thin films using neural networks
Kim, Chang Eun; Moon, Pyung; Yun, Ilgu [School of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemoon-gu, Seoul 120-749 (Korea); Kim, Sungyeon; Myoung, Jae-Min [Department of Materials Science and Engineering, Yonsei University, 262 Seongsanno, Seodaemoon-gu, Seoul 120-749 (Korea); Jang, Hyeon Woo; Bang, Jungsik [LG Chem, Ltd., Research Park, 104-1 Moonji-Dong, Yuseng-Gu, Daejeon 305-380 (Korea)
2010-07-15
In this paper, the thermal annealing process modeling for the optical bandgap of ZnO:Ga thin films for transparent conductive oxide was presented using neural network (NNets) based on error backpropagation (BPNN) algorithm and multilayer perceptron (MLP). The thermal annealing process of ZnO:Ga thin films were analyzed by general factorial experimental design. The annealing temperature and film thickness were considered as input factors. To model the nonlinear annealing process, 6 experiments were trained by BPNN which has 2-4-1 structures and 2 additional samples were experimented to verify the predicted models. The output response model on optical bandgap and carrier concentration of ZnO:Ga thin films trained by BPNN was represented by surface plot of response surface model. Based on the modeling results, NNets can provide sufficient correspondence between the predicted output values and the measured. The optical bandgap variation of ZnO:Ga thin films by annealing is due to increased carrier concentration and explained by Burstein-Moss effect. The thermal annealing process is nonlinear and complex but the output response can be predicted by the NNets model. (Abstract Copyright [2010], Wiley Periodicals, Inc.)
Artificial topological models based on a one-dimensional spin-dependent optical lattice
Zheng, Zhen; Pu, Han; Zou, Xubo; Guo, Guangcan
2017-01-01
Topological matter is a popular topic in both condensed matter and cold-atom research. In the past decades, a variety of models have been identified with fascinating topological features. Some, but not all, of the models can be found in materials. As a fully controllable system, cold atoms trapped in optical lattices provide an ideal platform to simulate and realize these topological models. Here we present a proposal for synthesizing topological models in cold atoms based on a one-dimensional spin-dependent optical lattice potential. In our system, features such as staggered tunneling, staggered Zeeman field, nearest-neighbor interaction, beyond-near-neighbor tunneling, etc. can be readily realized. They underlie the emergence of various topological phases. Our proposal can be realized with current technology and hence has potential applications in quantum simulation of topological matter.
Constraints on Disks Models of The Big Blue Bump from UV/Optical/IR Observations
Antonucci, R
1998-01-01
Optical/UV observations provide many constraints on accretion disk models of AGN which aren't always appreciated by modelers of the X-ray emission (or sometimes even of the optical/UV emission). The spectral behavior at the Ly edge, the polarization, the continuum slopes and breaks, and the variability timescales and phasing all conflict with simple models and strongly constrain the more Baroque ones. Partial-covering absorbers and microlensing data suggest that the radiation is not released simply according to where the potential drop (modified by standard viscous transport) takes place. On the other hand, the orientation-based unified model is in accord with the K-\\alpha inclination distributions for the AGN spectral classes, basing the latter on the limited existing data and theoretical understanding.
Causality issues of particle detector models in QFT and Quantum Optics
Martin-Martinez, Eduardo
2015-01-01
We analyze the constraints that causality imposes on some of the particle detector models employed in quantum field theory in general, and in particular on those used in quantum optics (or superconducting circuits) to model atoms interacting with light. Namely, we show that disallowing faster-than-light communication can impose severe constraints on the applicability of particle detector models in three different common scenarios: 1) when the detectors are spatially smeared, 2) when a UV cutoff is introduced in the theory and 3) under one of the most typical approximations made in quantum optics: the rotating-wave approximation. We identify in which scenarios the models' causal behaviour can be cured and in which it cannot.
Modeling the spectral optical properties of ammonium sulfate and biomass burning aerosols
Grant, K.E.; Chuang, C.C.; Grossman, A.S.; Penner, J.E. [Michigan Univ., Ann Arbor, MI (United States)
1997-09-01
The importance of including the global and regional radiative effects of aerosols in climate models has increasingly been realized. Accurate modeling of solar radiative forcing due to aerosols from anthropogenic sulfate and biomass burning emissions requires adequate spectral resolution and treatment of spatial and temporal variability. The variation of aerosol spectral optical properties with local relative humidity and dry aerosol composition must be considered. Because the cost of directly including Mie calculations within a climate model is prohibitive, parameterizations from offline calculations must be used. Starting from a log-normal size distribution of dry ammonium sulfate, we developed optical properties for tropospheric sulfate aerosol at 15 relative humidities up to 99 percent. The resulting aerosol size distributions were then used to calculate bulk optical properties at wavelengths between 0.175 {micro}m and 4 {micro}m. Finally, functional fits of optical properties were made for each of 12 wavelength bands as a function of relative humidity. Significant variations in optical properties occurred across the total solar spectrum. Relative increases in specific extinction and asymmetry factor with increasing relative humidity became larger at longer wavelengths. Significant variation in single-scattering albedo was found only in the longest near-IR band. This is also the band with the lowest albedo. A similar treatment was done for aerosols from biomass burning. In this case, size distributions were taken as having two carbonaceous size modes and a larger dust mode. The two carbonaceous modes were considered to be humidity dependent. Equilibrium size distributions and compositions were calculated for 15 relative humidities and five black carbon fractions. Mie calculations and Chandrasekhar averages of optical properties were done for each of the resulting 75 cases. Finally, fits were made for each of 12 spectral bands as functions of relative humidity
AlQuwaiee, Hessa
2016-11-01
One of the potential solutions to the radio frequency (RF) spectrum scarcity problem is optical wireless communications (OWC), which utilizes the unlicensed optical spectrum. Long-range outdoor OWC are usually referred to in the literature as free-space optical (FSO) communications. Unlike RF systems, FSO is immune to interference and multi-path fading. Also, the deployment of FSO systems is flexible and much faster than optical fibers. These attractive features make FSO applicable for broadband wireless transmission such as optical fiber backup, metropolitan area network, and last mile access. Although FSO communication is a promising technology, it is negatively affected by two physical phenomenon, namely, scintillation due to atmospheric turbulence and pointing errors. These two critical issues have prompted intensive research in the last decade. To quantify the effect of these two factors on FSO system performance, we need effective mathematical models. In this work, we propose and study a generalized pointing error model based on the Beckmann distribution. Then, we aim to generalize the FSO channel model to span all turbulence conditions from weak to strong while taking pointing errors into consideration. Since scintillation in FSO is analogous to the fading phenomena in RF, diversity has been proposed too to overcome the effect of irradiance fluctuations. Thus, several combining techniques of not necessarily independent dual-branch free-space optical links were investigated over both weak and strong turbulence channels in the presence of pointing errors. On another front, improving the performance, enhancing the capacity and reducing the delay of the communication link has been the motivation of any newly developed schemes, especially for backhauling. Recently, there has been a growing interest in practical systems to integrate RF and FSO technologies to solve the last mile bottleneck. As such, we also study in this thesis asymmetric an RF-FSO dual-hop relay
Human tissue optical properties measurements and light propagation modelling
Dam, JS
2006-07-01
Full Text Available measurements and light propagation modelling J. S. Dam , A. Singh , and A. E. Karsten Biophotonics Group, National Laser Centre, CSIR, Pretoria. www.csir.co.za/biophotonics SAIP 2006 Slide 2 © CSIR 2006 www... and µ’s S a m p l e S a m p l e S a m p l e Integrating Sphere measurements “Measurements of the total transmittance and reflectance of a thin slab-shaped multiple scattering sample can yield the absorption- and the reduced...
Modeling Graphene Contrast on Copper Surfaces Using Optical Microscopy
2014-10-01
Determining whether graphene has been successfully synthesized often requires transfer to a support substrate such as glass or SiO2 . During the transfer... SiO2 thickness from Blake et al.23 In comparison, Fig. 6b shows the same graphene contrast calculations using an in-house Matlab model. 7... graphene : interference colors of ultrathin graphite on SiO2 . Nano Letters. 2007;7(9):2707–2710. 11 26. Jung I, Pelton M, Piner R, Dikin DA
Energy dependence of hadron spectra and multiplicities in p+p interactions
Puławski, Szymon
2015-05-11
The NA61/SHINE experiment at the CERN SPS aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. In order to reach these goals measurements of hadron production properties are performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei. Inclusive spectra of identified hadrons in p+p interactions at the SPS energies are presented as a function of transverse momentum, transverse mass and rapidity. The results are compared with the world data and theoretical models.
Energy dependence of the 4He(π+,π-) total cross section
Gräter, J.; Bilger, R.; Clement, H.; Meier, R.; Wagner, G. J.; Friedman, E.; Schepkin, M.; Amaudruz, P. A.; Felawka, L.; Ottewell, D.; Smith, G. R.; Ambardar, A.; Hofman, G. J.; Kermani, M.; Tagliente, G.; Bonutti, F.; Camerini, P.; Grion, N.; Rui, R.; Hong, P.; Mathie, E. L.; Tacik, R.; Clark, J.; Sevior, M. E.; Patarakin, O.
1998-09-01
The total cross section of the 4He(π+,π-) reaction was measured for π+ kinetic energies ranging from 70 to 130 MeV using the CHAOS spectrometer at TRIUMF and a liquid 4He target. Around Tπ=90 MeV, total cross sections exceed conventional model predictions by a factor of 3, whereas at Tπ=70 MeV and for Tπ>130 MeV the data are consistent with these calculations. An attempt is made to understand this behavior by assuming the production of the hypothetical d' dibaryon.
Mani, G.S.; Melkanoff, M.A.; Iori, I. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1963-07-01
The neutron penetrabilities and reaction cross-sections are presented in these tables for the case of an optical model potential for the nucleus, for nuclei up to mass 230. (authors) [French] Les penetrabilites et les sections efficaces de reaction pour les neutrons sont donnees dans ces tables en utilisant le modele du potentiel optique, pour les noyaux cibles jusqu'a la masse 230. (auteurs)
Hönicke, Philipp; Kolbe, Michael; Müller, Matthias; Mantler, Michael; Krämer, Markus; Beckhoff, Burkhard
2014-10-17
An experimental method for the verification of the individually different energy dependencies of L(1)-, L(2)-, and L(3)- subshell photoionization cross sections is described. The results obtained for Pd and Mo are well in line with theory regarding both energy dependency and absolute values, and confirm the theoretically calculated cross sections by Scofield from the early 1970 s and, partially, more recent data by Trzhaskovskaya, Nefedov, and Yarzhemsky. The data also demonstrate the questionability of quantitative x-ray spectroscopical results based on the widely used fixed jump ratio approximated cross sections with energy independent ratios. The experiments are carried out by employing the radiometrically calibrated instrumentation of the Physikalisch-Technische Bundesanstalt at the electron storage ring BESSY II in Berlin; the obtained fluorescent intensities are thereby calibrated at an absolute level in reference to the International System of Units. Experimentally determined fixed fluorescence line ratios for each subshell are used for a reliable deconvolution of overlapping fluorescence lines. The relevant fundamental parameters of Mo and Pd are also determined experimentally in order to calculate the subshell photoionization cross sections independently of any database.
Emission-energy dependence of ultrafast P-emission decay in ZnO from bulk to nanofilm
Wakaiki, Shuji, E-mail: s.wakaiki@mls.eng.osaka-u.ac.jp [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Ichida, Hideki [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Science and Technology Entrepreneurship Laboratory, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Bamba, Motoaki [Department of Physics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Kawase, Toshiki; Kawakami, Masaki [Department of Applied Physics, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Mizoguchi, Kohji [Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen, Naka-ku, Sakai, Osaka 599-8531 (Japan); Kim, DaeGwi; Nakayama, Masaaki [Department of Applied Physics, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Kanematsu, Yasuo [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Science and Technology Entrepreneurship Laboratory, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)
2014-08-01
We have performed time-resolved photoluminescence (PL) spectroscopy for ZnO thin films with thicknesses of 90, 460, and 2800 nm under intense excitation condition. We clearly observed the P emission due to inelastic exciton–exciton scattering. It was found that, in the 460- and 2800-nm thick samples, the decay time of the P emission considerably depends on the detection energy inversely proportional to the group velocity of the polariton in a bulk crystal with each factor of proportionality. In contrast, the energy dependence is less remarkable in the 90-nm thick sample. The decay times are basically shortened with a decrease in the film thickness. The thickness dependence of the P-emission-decay profiles is explained by considering the crossover from the polariton modes in the 2800-nm thick sample (bulk-like film) to the exciton-/photon-like modes in the 90-nm thick sample (nanofilm). - Highlights: • We clearly observed the P-PL dynamics due to inelastic exciton–exciton scattering. • The P-PL decay times are basically shortened with a decrease in the film thickness. • The P-PL decay time depends on the detection energy in the bulk-like sample. • The energy dependence of the P-PL decay time almost disappears in the 90-nm sample. • The thickness dependence is explained by the crossover between exciton and photon.
Solar Energetic Particle drifts and the energy dependence of 1 AU charge states
Dalla, S; Battarbee, M
2016-01-01
The event-averaged charge state of heavy ion Solar Energetic Particles (SEPs), measured at 1 AU from the Sun, typically increases with the ions' kinetic energy. The origin of this behaviour has been ascribed to processes taking place within the acceleration region. In this paper we study the propagation through interplanetary space of SEP Fe ions, injected near the Sun with a variety of charge states that are uniformly distributed in energy, by means of a 3D test particle model. In our simulations, due to gradient and curvature drifts associated with the Parker spiral magnetic field, ions of different charge propagate with very different efficiencies to an observer that is not magnetically well connected to the source region. As a result we find that, for many observer locations, the 1 AU event-averaged charge state , as obtained from our model, displays an increase with particle energy E, in qualitative agreement with spacecraft observations. We conclude that drift-associated propagation is a possible explan...
Quasiperiodic energy dependence of exciton relaxation kinetics in the sexithiophene crystal.
Petelenz, Piotr; Zak, Emil
2014-10-16
Femtosecond kinetics of fluorescence rise in the sexithiophene crystal is studied on a microscopic model of intraband relaxation, where exciton energy is assumed to be dissipated by phonon-accompanied scattering, with the rates calculated earlier. The temporal evolution of the exciton population is described by a set of kinetic equations, solved numerically to yield the population buildup at the band bottom. Not only the time scale but also the shape of the rise curves is found to be unusually sensitive to excitation energy, exhibiting unique quasiperiodic dependence thereon, which is rationalized in terms of the underlying model. Further simulations demonstrate that the main conclusions are robust with respect to experimental factors such as finite temperature and inherent spectral broadening of the exciting pulse, while the calculated fluorescence rise times are found to be in excellent agreement with experimental data available to date. As the rise profiles are composed of a number of exponential contributions, which varies with excitation energy, the common practice of characterizing the population buildup in the emitting state by a single value of relaxation time turns out to be an oversimplification. New experiments giving further insight into the kinetics and mechanism of intraband exciton relaxation are suggested.
Solar Energetic Particle Drifts and the Energy Dependence of 1 AU Charge States
Dalla, S.; Marsh, M. S.; Battarbee, M.
2017-01-01
The event-averaged charge state of heavy ion solar energetic particles (SEPs), measured at 1 au from the Sun, typically increases with the ions’ kinetic energy. The origin of this behavior has been ascribed to processes taking place within the acceleration region. In this paper we study the propagation through interplanetary space of SEP Fe ions, injected near the Sun with a variety of charge states that are uniformly distributed in energy, by means of a 3D test particle model. In our simulations, due to gradient and curvature drifts associated with the Parker spiral magnetic field, ions of different charge propagate with very different efficiencies to an observer that is not magnetically well connected to the source region. As a result we find that, for many observer locations, the 1 au event-averaged charge state , as obtained from our model, displays an increase with particle energy E, in qualitative agreement with spacecraft observations. We conclude that drift-associated propagation is a possible explanation for the observed distribution of versus E in SEP events, and that the distribution measured in interplanetary space cannot be taken to represent that at injection.
Improved analytical model for the field of index-guiding microstructured optical fibers
Sharma, Dinesh Kumar; Sharma, Anurag
2016-05-01
We present an improved version of our earlier developed analytical field model for the fundamental mode of index-guiding microstructured optical fibers (MOFs), to obtain better accuracy in the simulated results. Using this improved field model, we have studied the splice losses between an MOF and a traditional step-index single-mode fiber (SMF). Comparisons with available experimental and numerical simulation results have also been included.
1980-12-01
models by comparing model results to optical measurements made over Monterey Bay off the Central California coast of the U.S. Commanding Officer COPY...FPO SAN FRANCISCO 96654 OFFICER IN CHARGE NAVOCEANCOM OET MONTEREY, CA 93940 COMMANDING OFFICER OFFICE OF NAVAL RESEARCH EASTERN/ CENTRAL ...TECHNICIAN CITY, HAIFA ISRAEL 32000 INSTITUTO OE GEOFISICA U.N.A.M. BIBLIOTECA TORRE DE CIENCIAS, 3ER PISO CIUDAD UNIVERSITARIA MEXICO 20, D.F
Linear and nonlinear optics of surface plasmon toy-models of black holes and wormholes
Smolyaninov, I I
2003-01-01
Experimental and theoretical studies of linear and nonlinear optics of surface plasmon toy wormholes and black holes have been performed. These models are based on dielectric microdroplets on the metal surfaces and on nanoholes drilled in thin metal films. Toy surface plasmon black holes and wormholes are shown to exhibit strongly enhanced nonlinear optical behavior in the frequency range near the surface plasmon resonance of a metal-liquid interface. Various possibilities to emulate such nontrivial gravitation theory effects as Hawking radiation and Cauchy horizons are discussed.
Design of nanostructured solar cells using coupled optical and electrical modeling.
Deceglie, Michael G; Ferry, Vivian E; Alivisatos, A Paul; Atwater, Harry A
2012-06-13
Nanostructured light trapping has emerged as a promising route toward improved efficiency in solar cells. We use coupled optical and electrical modeling to guide optimization of such nanostructures. We study thin-film n-i-p a-Si:H devices and demonstrate that nanostructures can be tailored to minimize absorption in the doped a-Si:H, improving carrier collection efficiency. This suggests a method for device optimization in which optical design not only maximizes absorption, but also ensures resulting carriers are efficiently collected.
Empirical model of optical sensing via spectral shift of circular Bragg phenomenon
Mackay, Tom G
2009-01-01
Setting up an empirical model of optical sensing to exploit the circular Bragg phenomenon displayed by chiral sculptured thin films (CSTFs), we considered a CSTF with and without a central twist defect of $\\pi/2$ radians. The circular Bragg phenomenon of the defect-free CSTF, and the spectral hole in the co-polarized reflectance spectrum of the CSTF with the twist defect, were both found to be acutely sensitive to the refractive index of a fluid which infiltrates the void regions of the CSTF. These findings bode well for the deployment of CSTFs as optical sensors.
Dhairya A Dholakia; G K Solanki; S G Patel; M K Agarwal
2001-06-01
The optical energy gaps of WS2 single crystal were determined from the analysis of the absorption spectrum near the fundamental absorption edge at room temperature using light parallel to -axis incident normally on the basal plane. On the basis of two- and three-dimensional models it was found that both direct and indirect band transitions took place in WS2 and the indirect transition was of the allowed type. The optical energy gaps corresponding to both transitions were determined and the phonon energies associated with the indirect transitions estimated. The implications of the results have been discussed.
Congrong Li
2015-08-01
Full Text Available Forest canopy leaf area index (LAI inversion based on remote sensing data is an important method to obtain LAI. Currently, the most widely-used model to achieve forest canopy structure parameters is the Li-Strahler geometric-optical bidirectional reflectance model, by considering the effect of crown shape and mutual shadowing, which is referred to as the GOMS model. However, it is difficult to retrieve LAI through the GOMS model directly because LAI is not a fundamental parameter of the model. In this study, a gap probability model was used to obtain the relationship between the canopy structure parameter nR2 and LAI. Thus, LAI was introduced into the GOMS model as an independent variable by replacing nR2 The modified GOMS (MGOMS model was validated by application to Dayekou in the Heihe River Basin of China. The LAI retrieved using the MGOMS model with optical multi-angle remote sensing data, high spatial resolution images and field-measured data was in good agreement with the field-measured LAI, with an R-square (R2 of 0.64, and an RMSE of 0.67. The results demonstrate that the MGOMS model obtained by replacing the canopy structure parameter nR2 of the GOMS model with LAI can be used to invert LAI directly and precisely.
Chen, T., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se; Gatchell, M.; Stockett, M. H.; Schmidt, H. T.; Cederquist, H.; Zettergren, H., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se [Department of Physics, Stockholm University, S-106 91 Stockholm (Sweden); Delaunay, R.; Rousseau, P.; Adoui, L. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Université de Caen Basse-Normandie, Esplanade de la Paix, F-14032 Caen (France); Domaracka, A.; Huber, B. A. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Micelotta, E. R. [Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
2015-04-14
We have investigated the effectiveness of molecular hydrogen (H{sub 2}) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results are analyzed in view of molecular structure calculations and a simple collision model. We estimate that H{sub 2} formation becomes important for internal PAH temperatures exceeding about 2200 K, regardless of the PAH size and the excitation agent. This suggests that keV ions may effectively induce such reactions, while they are unlikely due to, e.g., absorption of single photons with energies below the Lyman limit. The present analysis also suggests that H{sub 2} emission is correlated with multi-fragmentation processes, which means that the [PAH-2H]{sup +} peak intensities in the mass spectra may not be used for estimating H{sub 2}-formation rates.
Energy dependence of fission-fragment mass distributions from strongly damped shape evolution
Randrup, J.; Möller, P.
2013-12-01
The recently developed treatment of Brownian shape evolution is refined to take account of the gradual decrease in microscopic effects as the nuclear excitation energy is raised. We construct effective potential-energy surfaces by multiplying the shell-plus-pairing correction term by a suppression factor that depends on the local excitation energy. While this approach is equivalent to the modification of the Fermi-gas level density parameter suggested by Ignatyuk [Sov. J. Nucl. Phys. 29, 450 (1979)], we adopt a more general functional form for the suppression factor, which is adjusted to measured charge yields for 234U(E*≈11MeV). The resulting model is benchmarked by comparison with 70 measured yields.
Ion-Sputter-Induced Nanodots on Si(11O): Ion Energy Dependence
LI Wei-Qing; LING Li; QI Le-Jun; YANG Xin-Ju; FAN Wen-Bin; GU Chang-Xin; LU Ming
2005-01-01
@@ Nanodot arrays were formed on Si(110) surface under normal-incident Ar+ ion sputtering at substrate temperature of 800 ℃.Theion flux was 20μA/cm2, and the ion energies were 1-5keV.The surface was imaged by an atomic force microscope (AFM).It was found that with the increasing ion energy, the average ellipticity of the dots changes in an oscillating manner; meanwhile the average dot size increases monotonously.Based on a dynamic continuum model, and taking into consideration the asymmetry of the Ehrlich-Schwoebel diffusions along the and crystallographic directions, we carry out the simulations, which reproduce the experimental results qualitatively.
Improved Reduced Models for Single-Pass and Reflective Semiconductor Optical Amplifiers
Dúill, Seán P Ó
2014-01-01
We present highly accurate and easy to implement, improved lumped semiconductor optical amplifier (SOA) models for both single-pass and reflective semiconductor optical amplifiers (RSOA). The key feature of the model is the inclusion of the internal losses and we show that a few subdivisions are required to achieve an accuracy of 0.12 dB. For the case of RSOAs, we generalize a recently published model to account for the internal losses that are vital to replicate observed RSOA behavior. The results of the improved reduced RSOA model show large overlap when compared to a full bidirectional travelling wave model over a 40 dB dynamic range of input powers and a 20 dB dynamic range of reflectivity values. The models would be useful for the rapid system simulation of signals in communication systems, i.e. passive optical networks that employ RSOAs, signal processing using SOAs and for implementing digital back propagation to undo amplifier induced signal distortions.
Radar model fusion of asteroid (4179) Toutatis via its optical images observed by Chang'e-2 probe
Zhao, Wei; Xiao, Ting; Liu, Peng; Sun, Lei; Huang, Jiangchuan; Tang, Xianglong
2016-06-01
Asteroid (4179) Toutatis has been modeling by ground-based radar observations until Dec 13th, 2012, when distinct optical images of Toutatis were captured during the Chang'e-2 flyby at the shortest distance for the first time. The surface details on Toutatis in the optical images are abundant enough to reinforce the radar model descriptions. Under this context, we customized a method of frequency domain data fusion, which combines the topography information of radar model and the 3rd dimension information estimated from optical image by shape from shading algorithm, and gave out a new Toutatis' radar model. A model with abundant surface characteristics had been resulted.
Probabilistic Model for Free-Space Optical Links Under Continental Fog Conditions
Marzuki
2010-09-01
Full Text Available The error characteristics of a free-space optical (FSO channel are signiﬁcantly different from the ﬁber based optical links and thus require a deep physical understanding of the propagation channel. In particular different fog conditions greatly inﬂuence the optical transmissions and thus a channel model is required to estimate the detrimental fog effects. In this paper we shall present the probabilistic model for radiation fog from the measured data over a 80 m FSO link installed at Graz, Austria. The fog events are classiﬁed into thick fog, moderate fog, light fog and general fog based on the international code of visibility range. We applied some probability distribution functions (PDFs such as Kumaraswamy, Johnson SB and Logistic distribution, to the actual measured optical attenuations. The performance of each distribution is evaluated by Q-Q and P-P plots. It is found that Kumaraswamy distribution is the best ﬁt for general fog, while Logistic distribution is the optimum choice for thick fog. On the other hand, Johnson SB distribution best ﬁts the moderate and light fog related measured attenuation data. The difference in these probabilistic models and the resultant variation in the received signal strength under different fog types needs to be considered in designing an efﬁcient FSO system.
Numerical Model for the Deformation of Nucleated Cells by Optical Stretchers
Sraj, Ihab; Marr, David W M; Eggleton, Charles D
2015-01-01
In this paper, we seek to model the deformation of nucleated cells by single diode-laser bar optical stretchers. We employ a recently developed computational model, the Dynamic Ray-Tracing method, to determine the stress distribution induced by the applied optical forces on a capsule encapsulating a nucleus of different optical properties. These forces are shape dependent and can deform real non-rigid objects; thus resulting in a dynamically changing optical stress distribution with cell and nucleus deformation. Chinese hamster ovary cell is a common biological cell that is of interest to the biomedical community because of their use in recombinant protein therapeutics and is an example of a nucleated cell. To this end, we model chinese hamster ovary cells as two three-dimensional elastic capsules of variable inner capsule size immersed in a fluid where the hydrodynamic forces are calculated using the Immersed Boundary Method. Our results show that the presence of a nucleus has a major effect on the force dis...
Modeling and experimental verification for a broad beam light transport in optical tomography.
Janunts, Edgar; Pöschinger, Thomas; Eisa, Fabian; Langenbucher, Achim
2010-01-01
This paper describes a general theoretical model for computing a broad beam excitation light transport in a 3D diffusion medium. The model is based on the diffusion approximation of the radiative transport equation. An analytical approach for the light propagation is presented by deriving a corresponding Green's function. A finite cylindrical domain with a rectangular cross section was considered as a 3D homogeneous phantom model. The results of the model are compared with corresponding experimental data. The measurements are done on solid and liquid phantoms replicating tissue-like optical properties.
Integrated Model of the Eye/Optic Nerve Head Biomechanical Environment
Ethier, C. R.; Feola, A.; Myers, J. G.; Nelson, E.; Raykin, J.; Samuels, B.
2017-01-01
Visual Impairment and Intracranial Pressure (VIIP) syndrome is a concern for long-duration space flight. Previously, it has been suggested that ocular changes observed in VIIP syndrome are related to the cephalad fluid shift that results in altered fluid pressures [1]. We are investigating the impact of changes in intracranial pressure (ICP) using a combination of numerical models, which simulate the effects of various environment conditions, including finite element (FE) models of the posterior eye. The specific interest is to understand how altered pressures due to gravitational changes affect the biomechanical environment of tissues of the posterior eye and optic nerve sheath. METHODS: Additional description of the numerical modeling is provided in the IWS abstract by Nelson et al. In brief, to simulate the effects of a cephalad fluid shift on the cardiovascular and ocular systems, we utilized a lumped-parameter compartment model of these systems. The outputs of this lumped-parameter model then inform boundary conditions (pressures) for a finite element model of the optic nerve head (Figure 1). As an example, we show here a simulation of postural change from supine to 15 degree head-down tilt (HDT), with primary outcomes being the predicted change in strains at the optic nerve head (ONH) region, specifically in the lamina cribrosa (LC), retrolaminar optic nerve, and prelaminar neural tissue (PLNT). The strain field can be decomposed into three orthogonal components, denoted as the first, second and third principal strains. We compare the peak tensile (first principal) and compressive (third principal) strains, since elevated strain alters cell phenotype and induces tissue remodeling. RESULTS AND CONCLUSIONS: Our lumped-parameter model predicted an IOP increase of c. 7 mmHg after 21 minutes of 15 degree HDT, which agreed with previous reports of IOP in HDT [1]. The corresponding FEM simulations predicted a relative increase in the magnitudes of the peak tensile