Role of positron-electron annihilation in Bhabha scattering
International Nuclear Information System (INIS)
Bhabha scattering refers to Bhabha's original work on electron-positron scattering which was published in the Proceedings of the Royal Society, London in 1936. Bhabha had published several other papers on positron interaction using Dirac's hole theory. However, the paper titled, 'The Scattering of Positron by Electrons with exchange on Dirac's Theory of Positron' was his crowning achievement, a process now is well known as Bhabha scattering which a positron has to undergo while passing through the matter before it annihilates to generate a real photon. Bhabha scattering contains three terms (i) A direct term due to positron-electron scattering (ii) An exchange term due to positron-electron annihilation followed by pair production and (iii) An interference term due to combination of both. At a time when not much was known about antiparticle, it was confusing whether such an exchange effect due to annihilation followed by pair production needs to be included in positron-electron scattering. If a positron is regarded as an independent particle that obeys Dirac equation, positron-electron scattering should not have any exchange effects. On the other hand, if the positron is regarded as the absence of an electron in the negative energy Dirac sea (hole), exchange effects can not be neglected. Both the school of thoughts will lead to different results. The experimental measurements would have resolved this ambiguity, but was not available at that time. Bhabha, however taking the clue from the Dirac's hole theory, pointed out that the exchange phenomena is an important aspect and should be taken into account in the scattering of any two particles which can annihilate each other and be created in pair. Thus, like Moller, Bhabha obtained a correct expression for Bhabha Scattering which was beautifully confirmed by experiment later on. In this talk, I will review briefly how Bhabha obtained the scattering formulae with a special emphasis on exchange effect that arises due to
Mini-review on Monte Carlo programs for Bhabha scattering
International Nuclear Information System (INIS)
We review the status of Monte Carlo generators presently used for simulations of the large-angle Bhabha process at electron-positron colliders of moderately high energy (flavour factories), operating at centre-of-mass energies between about 1 GeV and 10 GeV. It is shown how the theoretical accuracy reached by present Bhabha programs for physics at flavour factories is at the level of 0.1% and, therefore, comparable with that reached about a decade ago for luminosity monitoring through small-angle Bhabha scattering at LEP
On the Bhabha scattering for $z=2$ Lifshitz QED
Bufalo, R
2015-01-01
In this paper we compute and discuss the differential cross section of the Bhabha scattering in the framework of the $z=2$ Lifshitz QED. We start by constructing the classical solutions for the fermionic fields, in particular the completeness relations, and also deriving the theory's propagators. Afterwards, we compute the photon exchange and pair annihilation contributions for the Bhabha's process, and upon the results we establish the magnitude of the theory's free parameter by looking for small deviations of the QED tree results.
On the Bhabha scattering for $z=2$ Lifshitz QED
Bufalo, R.
2015-01-01
In this paper we compute and discuss the differential cross section of the Bhabha scattering in the framework of the $z=2$ Lifshitz QED. We start by constructing the classical solutions for the fermionic fields, in particular the completeness relations, and also deriving the theory's propagators. Afterwards, we compute the photon exchange and pair annihilation contributions for the Bhabha's process, and upon the results we establish the magnitude of the theory's free parameter by looking for ...
Measurement of radiative Bhabha and quasi-real Compton scattering
Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Coignet, G; Colijn, A P; Colino, N; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Della Volpe, D; Denes, P; De Notaristefani, F; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Duinker, P; Durán, I; Easo, S; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hidas, P; Hirschfelder, J; Van Hoek, W C; Hofer, H; Hoorani, H; Hou, S R; Hu, G; Iashvili, I; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Lacentre, P E; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lavorato, A; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Marchesini, P A; Marian, G; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Migani, D; Mihul, A; Van Mil, A J W; Milcent, H; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Moulik, T; Mount, R; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Organtini, G; Ostonen, R; Palit, S; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Pothier, J; Produit, N; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Sakar, S; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stone, H; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Uchida, Y; Ulbricht, J; Valente, E; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Vlachos, S; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z P; Zhou, B; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F; Zilizi, G
1998-01-01
We report on a study of radiative Bhabha and quasi-real Compton scattering at centre-of-mass energies between 50~{\\GeV} and 170~{\\GeV} and 20~{\\GeV} and 140~{\\GeV}, respectively, using the L3 detector at LEP. The analysis is based on data corresponding to an integrated luminosity of $232.2 \\,\\pb$. A total of 2856 radiative Bhabha and 4641 Compton scattering events are collected. Total and differential cross sections for both reactions are presented and found to be in good agreement with QED expectations. Our measurement of Compton scattering at the highest energies obtained so far is used to derive exclusion limits on the coupling $\\lambda$ for the on-shell production of an excited electron $\\e^{\\star}$ decaying into a $\\gamma\\e$ pair in the mass range $20 \\gev < m_{\\e^{\\star}} < 170 \\gev$.
Small angles Bhabha scattering: two loop approximation
International Nuclear Information System (INIS)
The elastic and inelastic cross sections for small angles e+e- scattering at high energies are considered. We prove that all the diagrams with two or more virtual photons in scattering channel may be omitted when calculating the radiative corrections with accuracy of the order 0.1%. It is the consequence of the generalized eikonal representation for elastic and inelastic amplitudes. We take into account the processes of single and double bremsstrahlung in the same and opposite directions and the pair production processes. Basing on this calculations we construct the combined formula for the inclusive scattering electron and positron cross section in terms of the structure functions. 15 refs.; 10 figs
Large-angle Bhabha scattering at LEP 1
Beenakker, Wim; Passarino, Giampiero
1998-04-01
A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed. © 1998
Large-Angle Bhabha Scattering at LEP 1
Wim BeenakkerLeiden Univ.; Giampiero Passarino(Dipartimento di Fisica Teorica, Università di Torino, Italy)
1997-01-01
A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed.
Large-Angle Bhabha Scattering at LEP 1
Beenakker, W; Beenakker, Wim; Passarino, Giampiero
1998-01-01
A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed.
Moeller and Bhabha scattering in the noncommutative standard model
International Nuclear Information System (INIS)
We study the Moeller and Bhabha scattering in the noncommutative extension of the standard model using the Seiberg-Witten maps of this to first order of the noncommutative parameter θμν. We look at the angular distribution dσ/dΩ to explore the noncommutativity of space-time at around ΛNC∼TeV and find that the distribution deviates significantly from the one obtained from the commutative version of the standard model
Virtual two-loop corrections to Bhabha scattering
International Nuclear Information System (INIS)
The author has developed methods for the calculation of contributions from six ladder-like diagrams to Bhabha scattering. The leading terms both for separate diagrams and for the sum of the gauge-invariant set of all diagrams have been calculated. The study has been limited to contributions from Feynman diagrams without real photons, and all calculations have been done with s>> |t| >>m2, where s is the center of mass energy squared, t is the square of the transferred four-momentum, and m is the electron mass. For the separate diagrams the results depend upon how λ2 is related to s, |t| and m2, whereas the leading term of the sum of the six diagrams is the same in the cases that have been considered. The methods described should be valuable for calculations of contributions from other Feynman diagrams, in particular QED corrections to Bhabha scattering or pair production at small angles. 23 refs., 5 figs., 5 tabs
Large-Angle Bhabha Scattering and Luminosity at Flavour Factories
Calame, Carlo M Carloni; Montagna, G; Nicrosini, O; Piccinini, Fulvio
2000-01-01
The luminosity determination of electron-positron colliders operating in the region of low-lying hadronic resonances (E_cm ~ 1-10 GeV), such as BEPC/BES, DAPHNE, KEKB, PEP-II and VEPP-2M, requires the precision calculation of the Bhabha process at large scattering angles. In order to achieve a theoretical accuracy at a few 0.1% level, the inclusion of radiative corrections is mandatory. The phenomenologically relevant effect of QED corrections is taken into account in the framework of the Parton Shower (PS) method, which is employed both for cross section calculation and event generation. To test the reliability of the approach, a benchmark calculation, including exact O(alpha) corrections and higher-order leading logarithmic contributions, is developed as well and compared in detail with the PS predictions. The effect of O(alpha) next-to-leading and higher-order leading corrections is investigated in the presence of realistic event selections for the Bhabha process at the Phi-factories. A new Monte Carlo gen...
First order radiative corrections to Bhabha scattering in d dimensions
International Nuclear Information System (INIS)
The luminosity measurement at the projected International Linear e+e- Collider ILC is planned to be performed with forward Bhabha scattering with an accuracy of the order of 10-4. A theoretical prediction of the differential cross-section has to include one-loop weak corrections, with leading higher order terms, and the complete two-loop QED corrections. Here, we present the weak part and the virtual one-loop photonic corrections. For the photonic corrections, the expansions in ε = (4 - d)/2 are derived with inclusion of the terms of order ε in order to match the two-loop accuracy. For the photonic box master integral in d dimensions we compare several different methods of evaluation. (Orig.)
Polarized Bhabha scattering and a precision measurement of the electron neutral current couplings
International Nuclear Information System (INIS)
Bhabha scattering with polarized electrons at the Z0 resonance has been measured with the SLD experiment at the SLAC Linear Collider. The first measurement of the left-right asymmetry in Bhabha scattering is presented, yielding the effective weak mixing angle of sinθeffW=0.2245±0.0049±0.0010. The effective electron couplings to the Z0 are extracted from a combined analysis of polarized Bhabha scattering and the left-right asymmetry previously published: υe=-0.0414±0.0020 and ae=-0.4977±0.0045
Eponymous citations to Homi Jehangir Bhabha
Swarna, T.; Kalyane, V. L.; Prakasan, E. R.; Vijai Kumar, *
2004-01-01
The epoch-making research by H. J. Bhabha has gained eponymous status synonymous with his name and international fame. Out of the 427 eponymous bibliographic records for H. J. Bhabha retrieved from the Science Citation Index (1982-2002), majority of the records were for: bhabha scattering (290), angle bhabha scattering (42), small angle bhabha scattering (21), radiative bhabha scattering (17), large-angle bhabha scattering (16), resonant bhabha scattering (12), and low-angle bhabha scattering...
Electroweak coupling measurements from polarized Bhabha scattering at the Z0 resonance
International Nuclear Information System (INIS)
The cross section for Bhabha scattering (e+e- → e+e-) with polarized electrons at the center of mass energy of the Z0 resonance has been measured with the SLD experiment at the SLAC Linear Collider (SLC) during the 1992 and 1993 runs. The first measurement of the left-right asymmetry in Bhabha scattering (ALRe+e- (θ)) is presented. From ALRe+e-(θ) the effective weak mixing angle is measured to be sin2θWeff = 0.2245 ± 0.0049 ± 0.0010. The effective electron vector and axial vector couplings to the Z0 are extracted from a combined analysis of the polarized Bhabha scattering data and the left-right asymmetry (ALR) previously published by this collaboration. From the combined 1992 and 1993 data the effective electron couplings are measured to be ve = -0.0414 ± 0.0020 and ae = -0.4977 ± 0.0045
The planar four-point master integrals for massive two-loop Bhabha scattering
International Nuclear Information System (INIS)
We present the values of the complete set of planar four-point Master Integrals needed for massive Bhabha scattering in the limit of fixed angle and high energy at the two-loop level. The integrals have been calculated using direct expansions of Mellin-Barnes representations, followed by a resummation of resulting harmonic series. (Orig.)
The complete electroweak effect and perfection of Bhabha scattering in the standard model
International Nuclear Information System (INIS)
In this paper, we make a close and systematic research on Bhabha scattering in the electroweak unification of the standard model (SM). In concrete research methods we make the quantum field theory of perturbation theory in a new computing mode -renormalization chain propagation theory, and do an application to the Bhabha scattering calculation research. In SM, in order to consider complete electrical weak effect about Bhabha scattering internal process, we seek out the complex renormalization mixing-loop chain propagators constituted by photon y and intermediate boson Z0, and then calculate the Bhabha scattering cross section about this kind of propagator by transfer complete electrical weak reaction. Within the observed errors, the calculation results are in good agreement with the experimental values. Also, the main research results not only confirm the action of the particle reaction accuracy by SM theory for describing the electrical weak effect; but also suggests the SM theory may be a per ect theory and that the theory prophecy's Higgs 'mysterious particles' (which is of particular concern in the field of academic) have the large possibility to be eventually found. (authors)
Investigation of vacuum polarization in t-channel radiative Bhabha scattering
International Nuclear Information System (INIS)
We discuss the possibility of a precision measurement of vacuum polarization in t-channel radiative Bhabha scattering at a high luminosity collider. For illustration, the achievable precision is estimated for the BaBar experiment at PEP-II and for the OPAL experiment at LEP. (orig.)
A study of low Q2 radiative Bhabha scattering
International Nuclear Information System (INIS)
This thesis presents a study of electron-positron scattering, via nearly real photon exchange, where in the process one or more high energy photons are produced. The motivations behind the work are twofold. Firstly, the study is a sensitive test of the theory of electron-photon interactions, quantum electrodynamics. A deviation from the theory could indicate that the electron is a composite particle. Secondly, a thorough understanding of this process is necessary for experiments to be done in the near future at the Stanford Linear Collider and the LEP facility at CERN. Calculations for the process to third and fourth order in pertubation theory are described. Methods for simulating the process by a Monte Carlo event generator are given. Results from the calculations are compared to data from the Mark II experiment at the PEP storage ring. The ratio of measured to calculated cross sections are 0.993 /+-/ 0.017 /+-/ 0.015 and 0.99 /+-/ 0.16 /+-/ 0.08 for final states with one and two observed photons respectively, where the first errors are statistical and the second systematic. The excellent agreement verifies the calculations of the fourth order radiative correction. No evidence for electron substructure is observed
BBBREM - Monte Carlo simulation of radiative Bhabha scattering in the very forward direction
International Nuclear Information System (INIS)
A fast and simple Monte Carlo program is presented that simulates single Bremsstrahlung in Bhabha scattering, e+e-→e+e-γ, without constraints on scattering angles. This allows the study of this process at arbitrarily small, or even vanishing, scattering angles. Experimental cuts can be imposed on an event-by-event basis, allowing for detailed studies of the process as a limitation to beam lifetimes, or a luminosity-measuring device, in e+e- storage rings. As an application, we show that the easy introduction of a cut-off parameter, corresponding to the characteristic distance between particles in the e± bunches, gives a reduced cross section that is in good agreement with observation. (orig.)
Virtual hadronic and heavy-fermion Ο(α2) corrections to Bhabha scattering
International Nuclear Information System (INIS)
Effects of vacuum polarization by hadronic and heavy-fermion insertions were the last unknown two-loop QED corrections to high-energy Bhabha scattering. Here we describe the corrections in detail and explore their numerical influence. The hadronic contributions to the virtual O(α2) QED corrections to the Bhabha-scattering cross-section are evaluated using dispersion relations and computing the convolution of hadronic data with perturbatively calculated kernel functions. The technique of dispersion integrals is also employed to derive the virtual O(α2) corrections generated by muon-, tau- and top-quark loops in the small electron-mass limit for arbitrary values of the internal-fermion masses. At a meson factory with 1 GeV center-of-mass energy the complete effect of hadronic and heavy-fermion corrections amounts to less than 0.5 per mille and reaches, at 10 GeV, up to about 2 per mille. At the Z resonance it amounts to 2.3 per mille at 3 degrees; overall, hadronic corrections are less than 4 per mille. For ILC energies (500 GeV or above), the combined effect of hadrons and heavy fermions becomes 6 per mille at 3 degrees; hadrons contribute less than 20 per mille in the whole angular region. (orig.)
Differential equations and massive two-loop Bhabha scattering. The B512m3 case
International Nuclear Information System (INIS)
The two-loop box contributions to massive Bhabha scattering may be reduced to two-loop box master integrals (MIs) with five, six, and seven internal lines, plus vertices and self energies. The self-energy and vertex MIs may be solved analytically by the differential equations (DE) method. This is true for only few of the box masters. Here we describe some details of the analytical determination, including constant terms in ε=(4-d)/2, of the complicated topology B5l2m3 (with 5 lines, 2 of them being massive). With the DE approach, three of the four coupled masters have been solved in terms of (generalized) standard Harmonic Polylogarithms. (Orig.)
NNLO massive corrections to Bhabha scattering and theoretical precision of BabaYaga rate at NLO
Energy Technology Data Exchange (ETDEWEB)
Carloni Calame, C.M. [Southampton Univ. (United Kingdom). School of Physics; Czyz, H.; Gluza, J.; Gunia, M. [Silesia Univ., Katowice (Poland). Dept. of Field Theory and Particle Physics; Montagna, G. [Pavia Univ. (Italy). Dipt. di Fisica Nucleare e Teorica; INFN, Sezione di Pavia (Italy); Nicrosini, O.; Piccinini, F. [INFN, Sezione di Pavia (Italy); Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Worek, M. [Bergische Univ., Wuppertal (Germany). Fachbereich Physik
2011-12-15
We provide an exact calculation of next-to-next-to-leading order (NNLO) massive corrections to Bhabha scattering in QED, relevant for precision luminosity monitoring at meson factories. Using realistic reference event selections, exact numerical results for leptonic and hadronic corrections are given and compared with the corresponding approximate predictions of the event generator BabaYaga rate at NLO. It is shown that the NNLO massive corrections are necessary for luminosity measurements with per mille precision. At the same time they are found to be well accounted for in the generator at an accuracy level below the one per mille. An update of the total theoretical precision of BabaYaga rate at NLO is presented and possible directions for a further error reduction are sketched. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Carloni Calame, C. [Southampton Univ. (United Kingdom). School of Physics; Czyz, H.; Gluza, J.; Gunia, M. [Silesia Univ., Katowice (Poland). Dept. of Field Theory and Particle Physics; Montagna, G. [Pavia Univ. (Italy). Dipt. di Fisica Nucleare e Teorica; INFN, Sezione di Pavia (Italy); Nicrosini, O.; Piccinini, F. [INFN, Sezione di Pavia (Italy); Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Worek, M. [Wuppertal Univ. (Germany). Fachbereich C Physik
2011-07-15
Virtual fermionic N{sub f}=1 and N{sub f}=2 contributions to Bhabha scattering are combined with realistic real corrections at next-to-next-to-leading order in QED. The virtual corrections are determined by the package BHANNLOHF, and real corrections with the Monte Carlo generators BHAGEN-1PH, HELAC-PHEGAS and EKHARA. Numerical results are discussed at the energies of and with realistic cuts used at the {phi} factory DA{phi}NE, at the B factories PEP-II and KEK, and at the charm/{tau} factory BEPC II. We compare these complete calculations with the approximate ones realized in the generator BABAYAGA rate at NLO used at meson factories to evaluate their luminosities. For realistic reference event selections we find agreement for the NNLO leptonic and hadronic corrections within 0.07% or better and conclude that they are well accounted for in the generator by comparison with the present experimental accuracy. (orig.)
High-sensitivity measurements of the excitation function for Bhabha scattering at MeV energies
International Nuclear Information System (INIS)
Using a monochromatic e+ beam scattered on a Be foil and a high-resolution detector device, the excitation function for elastic e+e- scattering was measured with a statistical accuracy of 0.25% in 1.4 keV steps in the c.m.-energy range between 770 keV and 840 keV (1.79 - 1.86 MeV/c2) at c.m. scattering angles between 800 and 1000 (FWHM). Within the experimental sensitivity of 0.5 b.eV/sr (c.m.) for the energy-integrated differential cross section no resonances were observed (97% CL). From this limit we infer that a hypothetical spinless resonant state should have a width of less than 1.9 meV corresponding to a lifetime limit of 3.5x10-13 s. This limit establishes the most stringent bound for new particles in this mass range derived from Bhabha scattering and is independent of assumptions about the internal structure of the hypothetical particles. Less sensitivite limits were, in addition, derived around 520 keV c.m. energy (≅ 1.54 MeV/c2) from an investigation with a thorium and a mylar foil as scatterers. (orig.)
Institute of Scientific and Technical Information of China (English)
JIANG Min; FANG Zhen-Yun; SANG Wen-Long; GAO Fei
2006-01-01
@@ In the minimum electromagnetism coupling model of interaction between photon and electron (positron), we accurately calculate photon chain renormalized propagator and obtain the accurate result of differential cross section of Bhabha scattering with a photon chain renormalized propagator in quantum electrodynamics. The related radiative corrections are briefly reviewed and discussed.
Electroweak coupling measurements from polarized Bhabha scattering at the Z{sup 0} resonance
Energy Technology Data Exchange (ETDEWEB)
Pitts, K.T.
1994-03-01
The cross section for Bhabha scattering (e{sup +}e{sup {minus}} {yields} e{sup +}e{sup {minus}}) with polarized electrons at the center of mass energy of the Z{sup 0} resonance has been measured with the SLD experiment at the Stanford Linear Accelerator Center during the 1992 and 1993 runs. The electroweak couplings of the electron are extracted. At small angles the measurement is done in the SLD Silicon/Tungsten Luminosity Monitor (LMSAT). A detailed description of the design, construction, commissioning and operation of the LMSAT is provided. The integrated luminosity for 1992 is measured to be L = 420.86{plus_minus}2.56 (stat){plus_minus}4.23 (sys) nb{sup {minus}1}. The luminosity asymmetry for polarized beams is measured to be A{sub LR}(LUM) = (1.7 {plus_minus} 6.4) {times} 10{sup {minus}3}. The large angle polarized Bhabha scattering reveals the effective electron vector and axial vector couplings to the Z{sup 0} through the measurement of the Z{sup 0} {yields} e{sup +}e{sup {minus}} partial width, {Gamma}{sub ee}, and the parity violation parameter, A{sub e}. From the combined 1992 and 1993 data the effective electron vector and axial vector couplings are measured to be {bar g}{sub v}{sup e} = {minus}0.0495{plus_minus}0.0096{plus_minus}0.0030, and {bar g}{sub {alpha}}{sup e} = {minus}0.4977{plus_minus}0.0035{plus_minus}0.0064 respectively. The effective weak mixing angle is measured to be sin{sup 2}{theta}{sub W}{sup eff} = 0.2251{plus_minus}0.0049{plus_minus}0.0015. These results are compared with other experiments.
Electroweak coupling measurements from polarized Bhabha scattering at the Z0 resonance
International Nuclear Information System (INIS)
The cross section for Bhabha scattering (e+e- → e+e-) with polarized electrons at the center of mass energy of the Z0 resonance has been measured with the SLD experiment at the Stanford Linear Accelerator Center during the 1992 and 1993 runs. The electroweak couplings of the electron are extracted. At small angles the measurement is done in the SLD Silicon/Tungsten Luminosity Monitor (LMSAT). A detailed description of the design, construction, commissioning and operation of the LMSAT is provided. The integrated luminosity for 1992 is measured to be L = 420.86±2.56 (stat)±4.23 (sys) nb-1. The luminosity asymmetry for polarized beams is measured to be ALR(LUM) = (1.7 ± 6.4) x 10-3. The large angle polarized Bhabha scattering reveals the effective electron vector and axial vector couplings to the Z0 through the measurement of the Z0 → e+e- partial width, Γee, and the parity violation parameter, Ae. From the combined 1992 and 1993 data the effective electron vector and axial vector couplings are measured to be bar gve = -0.0495±0.0096±0.0030, and bar gαe = -0.4977±0.0035±0.0064 respectively. The effective weak mixing angle is measured to be sin2θWeff = 0.2251±0.0049±0.0015. These results are compared with other experiments
Measurement of the running of the QED coupling in small-angle Bhabha scattering at LEP
Abbiendi, G; Åkesson, P F; Alexander, G; Anagnostou, G; Anderson, K J; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; Dallavalle, G M; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, F L; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giacomelli, R; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, R J; Herten, G; Heuer, R D; Hill, J C; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Mashimo, T; Mättig, P; McKenna, J A; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L
2006-01-01
Using the OPAL detector at LEP, the running of the effective QED coupling alpha(t) is measured for space-like momentum transfer through its effect on the angular spectrum of small-angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain: Delta alpha(-6.07GeV^2) - Delta alpha(-1.81GeV^2) = (440 pm 58 pm 43 pm 30) X 10^-5, where the first error is statistical, the second is the experimental systematic and the third is the theoretical uncertainty. This is the strongest direct evidence ever presented that the running of alpha is consistent with Standard Model expectations. The null hypothesis that alpha remains constant within the above interval of -t is excluded with a significance above 5sigma. Similarly, our results are inconsistent at the level of 3sigma with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear experimental evidence that hadronic loops also contribute.
Precise measurement of Bhabha scattering at a center-of-mass energy of 57.77 GeV
International Nuclear Information System (INIS)
Bhabha scattering at a center-of-mass energy of 57.77 GeV has been measured using the VENUS detector at KEK TRISTAN. The precision is better than 1% in scattering angle regions of |cosθ|≤0.743 and 0.822≤cosθ≤0.968. A model-independent scattering-angle distribution is extracted from the measurement. The distribution is in good agreement with the prediction of the standard electroweak theory. The sensitivity to underlying theories is examined, after unfolding the photon-radiation effect. The q2 dependence of the photon vacuum polarization, frequently interpreted as a running of the QED fine-structure constant, is directly observed with a significance of three standard deviations. The Z0 exchange effect is clearly seen when the distribution is compared with the prediction from QED (photon exchanges only). The agreement with the standard theory leads us to constraints on extensions of the standard theory. In all quantitative discussions, correlations in the systematic error between angular bins are taken into account by employing an error matrix technique. copyright 1997 The American Physical Society
Energy Technology Data Exchange (ETDEWEB)
Guenther, P.
2005-06-01
Using the high precision OPAL Silicon-Tungsten luminometer at LEP, the running of the effective QED coupling {alpha}(t) is measured for space-like momentum transfer 1.81 {<=} -t {<=} 6.07 GeV{sup 2} through its effect on the angular spectrum of small angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain a strong direct evidence that the running of {alpha}(t) is consistent with standard model expectations. The null hypothesis that {alpha} remains constant within the above interval of -t is excluded with a significance above 5{sigma}: {delta}{alpha}(-6.07 GeV{sup 2}) - {delta}{alpha}(-1.81 GeV{sup 2}) = 0.00450 {+-} 0.00079 The hadronic contribution to the running of the coupling has been estimated to be: {delta}{alpha}{sub had}(-6.07 GeV{sup 2}) - {delta}{alpha}{sub had}(-1.81 GeV{sup 2}) = 0.00248 {+-} 0.00079. This result is inconsistent at the level of more than 3{sigma} with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear space-like experimental evidence that hadronic loops also contribute. (orig.)
International Nuclear Information System (INIS)
Using the high precision OPAL Silicon-Tungsten luminometer at LEP, the running of the effective QED coupling α(t) is measured for space-like momentum transfer 1.81 ≤ -t ≤ 6.07 GeV2 through its effect on the angular spectrum of small angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain a strong direct evidence that the running of α(t) is consistent with standard model expectations. The null hypothesis that α remains constant within the above interval of -t is excluded with a significance above 5σ: Δα(-6.07 GeV2) - Δα(-1.81 GeV2) = 0.00450 ± 0.00079 The hadronic contribution to the running of the coupling has been estimated to be: Δαhad(-6.07 GeV2) - Δαhad(-1.81 GeV2) = 0.00248 ± 0.00079. This result is inconsistent at the level of more than 3σ with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear space-like experimental evidence that hadronic loops also contribute. (orig.)
Two-loop Bhabha Scattering at High Energy beyond Leading Power Approximation
Penin, Alexander A
2016-01-01
We evaluate the two-loop ${\\cal O}(m_e^2/s)$ contribution to the wide-angle high-energy electron-positron scattering in the double-logarithmic approximation. The origin and the general structure of the power-suppressed double logarithmic corrections are discussed in detail.
Experimental exclusion of neutral resonances in Bhabha scattering at MeV energies
International Nuclear Information System (INIS)
Using an active-shadow technique and a monoenergetic e+ beam at the high-flux reactor of ILL, we pursued the search for long-lived (> 5x10-13 s) neutral resonances which could be formed in e+e- scattering around an invariant mass of 1.8 MeV/c2. With a significantly improved experimental sensitivity we found no evidence for such a narrow resonance decaying into e+e- pairs. From our whole investigations, the model-independent stringent lower limits (95% CL) of 5x10-11 s and 1x10-10 s can be set on the lifetime of hypothetical J = 0 and J = 1 resonances, respectively. Our conclusive results rule out theoretical proposals that involve neutral particles or e+e- bound states in this mass range, as an explanation of the e+e- lines observed at GSI. (orig.)
A study of low Q/sup 2/ radiative Bhabha scattering
Energy Technology Data Exchange (ETDEWEB)
Karlen, D.A.
1988-03-01
This thesis presents a study of electron-positron scattering, via nearly real photon exchange, where in the process one or more high energy photons are produced. The motivations behind the work are twofold. Firstly, the study is a sensitive test of the theory of electron-photon interactions, quantum electrodynamics. A deviation from the theory could indicate that the electron is a composite particle. Secondly, a thorough understanding of this process is necessary for experiments to be done in the near future at the Stanford Linear Collider and the LEP facility at CERN. Calculations for the process to third and fourth order in pertubation theory are described. Methods for simulating the process by a Monte Carlo event generator are given. Results from the calculations are compared to data from the Mark II experiment at the PEP storage ring. The ratio of measured to calculated cross sections are 0.993 /+-/ 0.017 /+-/ 0.015 and 0.99 /+-/ 0.16 /+-/ 0.08 for final states with one and two observed photons respectively, where the first errors are statistical and the second systematic. The excellent agreement verifies the calculations of the fourth order radiative correction. No evidence for electron substructure is observed.
Field, J. H.
1994-03-01
A new event generator for lepton pair production and wide angle Bhabha scattering, BHAGENE3, is presented. Both electroweak and higher order (beyond O(α) QED corrections are included. Comparisons are made with results from the programs, based on the structure function formalism, ALIBABA, TOPAZ0 and ZFITTER. For the case of the final states l+l-γγ ( l = e, μ, τ) BHAGENE3 results are compared with those of Monte Carlo generators that use the exact O( α2) amplitudes.
Symmetric Moeller/Bhabha luminosity monitor for the OLYMPUS experiment
International Nuclear Information System (INIS)
The OLYMPUS experiment ran on the DORIS storage ring at DESY, Hamburg to measure the elastic cross sections for both positron and electron scattering from hydrogen to quantify the two-photon contribution to elastic ep scattering. Two-photon exchange is widely considered to be responsible for the the discrepancy in the proton form factor ratio determined using the Rosenbluth technique and polarization transfer. The experiment alternated daily between positron and electron beams at 2.01 GeV incident on an unpolarized, internal, hydrogen gas target. The luminosity delivered to the experiment was monitored by a redundant set of detectors: a high precision, symmetric Moeller/Bhabha calorimeter and a tracking telescope at 12 degrees. The symmetric Moeller/Bhabha calorimeter was built at Mainz and consisted of two symmetric arrays of lead fluoride crystals. Results on the performance of the SYMB luminosity monitor will be presented together with an overview of the OLYMPUS experiment.
Limits on electron compositeness from Bhabha scattering
International Nuclear Information System (INIS)
We have studied the reaction e+e-→e+e- using data taken by the CELLO detector at 35 GeV centre of mass energy with an integrated luminosity of 86 pb-1. The differential cross section is found to agree with the Standard Model and is used to set limits on possible deviations from the pointlike structure of the electron. The lower limits obtained for the compositeness scale Λ range from 0.8 to 6.0 TeV (95% C.L.), depending on the structure of the current. (orig.)
Bhabha Atomic Research Centre : annual report 1990
International Nuclear Information System (INIS)
Research and development (R and D) activities of the Bhabha Atomic Research Centre (BARC) carried out during 1990 are reported. The main thrust of the R and D activities of BARC is on : (1)providing support to the nuclear power programme, (2)designing, building and utilising research reactors, (3)working in related frontline technologies, and also (4)basic research in frontier areas of science. These activities are described in brief under the chapters entitled : (1)Physical Sciences (2)Chemical Sciences (3)Materials and Material Science (4)Radioisotopes (5)Reactions (6)Fuel Cycle (7)Radiological Safety and Protection (8)Electronics and Instrumentation (9)Engineering Services (10)Life Sciences and (11)General. At the end of each chapter a list of papers and reports published in the subject field indicated by the title of the chapter is given. (N.B.). figs., tabs
Bhabha Atomic Research Centre annual report : 1989
International Nuclear Information System (INIS)
The main thrust of the various research and development (R and D) activities of the Bhabha Atomic Research Centre (BARC), Bombay, is towards the implementation of India's nuclear power programme. To that end, its R and D activities cover the entire nuclear fuel cycle, reactor technology; applications of radioisotopes and radiations in agriculture, medicine and industries; and radiation protection in nuclear installations. The report presents in summarised form the R and D activities carried out during 1989 in the chapters entitled: Physical Sciences, Chemical Sciences, Materials and Materials Sciences, Radioisotopes, Reactors, Fuel Cycle, Radiological Safety and Protection, Electronics and Instrumentation, Engineering Services, Life Sciences and General. At the end of each chapter, a list of publications by the staff scientists in the corresponding subject field is given. The list includes published journal articles and technical reports, and papers presented at conferences, symposia etc. The report also covers the R and D activities of the outstation units of BARC, namely, Nuclear Research Laboratory, Srinagar; High Altitude Research Laboratory, Gulmarg; and Variable Energy Cyclotron Centre, Calcutta. BARC is also engaged in basic an applied research in frontier areas of science such as plasma and fusion physics, accelerators and lasers, high temperature superconductivity, condensed matter physics, high pressure physics, high resolution spectroscopy, chemical reaction dynamics and laser induced chemistry, electronics and robotics: radiation biology, and genetic engineering. Report is illustrated with a number of figures, graphs, and coloured pictures. (M.G.B.) figs., refs
Bhabha Atomic Research Centre: annual report 1988
International Nuclear Information System (INIS)
The research and development (R and D) work carried out in the Bhabha Atomic Research Centre (BARC), Bombay during 1988 is summarised and presented in the sections entitled Physical Sciences, Chemical Sciences, Materials and Materials Science, Radioisotopes, Reactors, Fuel cycle, Radiological Safety and Protection, Electronics and Instrumentation, Engineering Services, Life Sciences and General. At the end of each section a list of publications is also given. The R and D work of the outstation units of BARC, namely, Nuclear Research Laboratory, Srinagar; High Altitute Research Laboratory, Gulmarg and Variable Energy Cyclotron Centre, Calcutta are also described in this report. Some of the highlights of the work during the year are: (1) Medium Energy Heavy Ion Accelerator (MEHIA) facility set up jointly by BARC and the Tata Institute of Fundamental Research (TIFR) at TIFR premises became fully operational in September 1988. A number of new compositions of high temperature supconducting materials were synthesized. The highest transition temperature achieved was 125 K. Research work to improve the quality of sintered uranium oxide pellets achieved the purpose. Nuclear fuels were fabricated by using sol-gel process. R and D work for 235 MWe and 500 MWe PHWR type reactors is continuing. Conceptual design of the fuel handling system for the prototype fast breeder reactor was finalised. 233U+Al alloy fuel for Kamini reactor was fabricated. Progress has been made in industrial applications of enzymes. Various applications of radioisotopes are being continued. Certain technologies and processes developed in the Centre were transferred to commercial agencies for large scale exploitation. (M.G.B.)
Measurement of low energy longitudinal polarised positron beams via a Bhabha polarimeter
Alexander, G; Alexander, Gideon; Reinherz-Aronis, Erez
2005-01-01
The introduction of a longitudinal polarised positron beam in an $e^+e^-$ linear collider calls for its polarisation monitoring and measurement at low energies near its production location. Here it is shown that a relatively simple Bhabha scattering polarimeter allows, at energies below 5000 MeV, a more than adequate positron beam longitudinal polarisation measurement by using only the final state electrons. It is further shown that out of the three, 10, 250 or 5000 MeV positron beam energy locations, where the polarisationmeasurement in the TESLA linear collider can be performed, the 250 MeV site is best suited for this task.
Scientometric dimensions of technical reports from Bhabha Atomic Research Centre
Swarna, T.; Kalyane, V. L.; Vijai Kumar, *
2002-01-01
Technical report is one of the media to record the scientific information generated by scientists and engineers, Bhabha Atomic Research Centre (BARC) published 554 technical reports during 1990-99 under the categories: External (373) and Internal (181), Engineering and technology generated 207 technical reports followed by chemistry, materials and earth sciences (129), while their interdisciplinary interactions resulted in 31 technical reports, Life and environmental sciences produced 42 tech...
H. J. Bhabha : a case study of synchronous references
Swarna, T.; Kalyane, V. L.; Prakasan, E. R.; Vijai Kumar, *
2003-01-01
Quantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha first quinquennium and fifth quinquennium of his research career had low Self-references; third quinquennium and fourth quinquennium had moderate Self-references; whereas second quinquennium had highest Self-references. The two major...
H.J. Bhabha: A case study of synchronous references
International Nuclear Information System (INIS)
Quantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha, the first quinquennium and fifth quinquennium of his research career had low self-references; the third quinquennium and the fourth quinquennium had moderate self-references; whereas the second quinquennium had the highest number of self-references. The two major clusters of self-references occurring during the second and third quinquenniums were indicators of active periods of knowledge-generating and faster communications. (author)
H.J. Bhabha: A case study of synchronous references
Energy Technology Data Exchange (ETDEWEB)
Swarna, T. [Scientific Information Resource Division, Knowledge Management Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)]. E-mail: tswarna@magnum.barc.ernet.in; Kalyane, V.L.; Prakasan, E.R.; Kumar, V. [Scientific Information Resource Division, Knowledge Management Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2006-07-01
Quantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha, the first quinquennium and fifth quinquennium of his research career had low self-references; the third quinquennium and the fourth quinquennium had moderate self-references; whereas the second quinquennium had the highest number of self-references. The two major clusters of self-references occurring during the second and third quinquenniums were indicators of active periods of knowledge-generating and faster communications. (author)
Achieving Homi Bhabha's vision for the future of India
International Nuclear Information System (INIS)
Full text: More than four decades ago, as Dr Homi Jehangir Bhabha pronounced the concept of the 3-stage nuclear program, he was addressing the need for nuclear energy in developing countries. His vision was to develop Indian nuclear infrastructure, considering the lack of domestic energy resources and the need to develop new technology. Nuclear Energy has a great role to play in India and India can now play a key role in the development of nuclear energy. If the planned role of the thorium resource makes the 3-stage program unique, France and India share the same vision about the overall role of nuclear energy. They both consider nuclear as part of the solution for a sustained economic growth in a carbon-constrained world, addressing climate change issues. France and India share the same nuclear history: France was one of the first countries to start cooperation with Indian nuclear institutes in the early 50's (CEA-TIFR agreement in 1951) and when international nuclear trade with India eventually resumed at the end of 2008, AREVA was the first supplier of natural uranium to DAE for use in NPCIL safeguarded reactors. India has great plans to develop its infrastructure and add electric generation capacities. In addition to the domestic effort and the strengths of the existing nuclear industrial and scientific base in the country, India can draw great benefits from cooperating with foreign reactor vendors: It will help capacity addition going faster and keeps in line with the 3-stage program. Nuclear power is a long-term investment that India can afford. The intrinsic benefits of larger size imported reactors in rapidly growing economies are manifold: benefits to the grid, ability to meet pace of demand faster, ability to place reactors closer to power utilization centers-all this has a true value, also called positive externalities. Efficient cooperation between Indian and foreign industries and efficient cooperation in project management will be key to achieve these
Bhabha Atomic Research Centre (BARC) annual report 1985-86
International Nuclear Information System (INIS)
The research and development (R and D) activities and accomplishments during the financial year 1985-86 of the Bhabha Atomic Research Centre, Bombay are reported. The BARC is a multidisciplinary laboratory engaged in R and D activities in the field of nuclear energy. The main thrust of the R and D activities of the Centre is aimed at: (1) achieving targets of India's nuclear power programme, (2) indigenisation of the various steps in the nuclear fuel cycle, (3) developing and propagating peaceful applications of nuclear science and technology in the country in fields such as agriculture, medicine and industry, (4) providing scientific support to regulatory functions associated with nuclear facilities and radiation protection activities in the country. The salient features of these R and D activities are described in the chapters entitled: (1) physical sciences, (2) chemical sciences, (3) materials and materials sciences, (4) life sciences, (5) radioisotopes, (6) reactors, (7) fuel cycle, (8) health and safety, (9) electronics and instrumentation, and (10) technical services. A list of publications by the staff-members during the report period is given at the end of each chapter. The R and D activities of the outstation units of BARC, namely, Nuclear Research Laboratory at Srinagar, High Altitude Research Laboratory at Gulmarg, Variable Energy Cyclotron Centre at Calcutta and Gauribidanur Seismic Array near Bangalore are also covered in the report. Other activities of the Centre include technology transfer and manpower training which are also described briefly. (M.G.B.)
Bhabha Atomic Research Centre: annual report 1986-87
International Nuclear Information System (INIS)
The Research and Development (R and D) work and achievements of the Bhabha Atomic Research Centre, Bombay, during the financial year 1986-1987 are reported. The R and D activities of BARC cover the entire nuclear fuel cycle, production and use of radioisotopes, radiation protection and also basic research in several disciplines. The report is presented in the chapters entitled: Physical Sciences, Chemical Sciences, Materials and Materials Science, Life Sciences, Radioisotopes, Reactors, Fuel Cycle, Health and Safety, Electronics and Instrumentation, Engineering and General Services. At the end of each chapter are listed the journal articles published, the paper presented at conferences, symposia etc. and technical reports issued by the scientists of BARC in the subject field indicated by the title of the chapter. The R and D work of the outstation units of BARC, namely, Nuclear Research Laboratory at Srinagar, High Altitute Research Laboratory at Gulmarg, Variable Energy Cyclotron Centre at Calcutta and Gauribidanur Seismic Array near Bangalore are also described in the report. The report concludes with a brief account of: (1) transfer of technologies developed at the Centre, (2) activities related to human resource development for nuclear programmes of the country, and (3) progress of design and construction work of Centre for Advanced Technology at Indore. (M.G.B.)
Signals of Z' boson in the Bhabha process within the LEP2 data set
Gulov, A. V.; Skalozub, V. V.
2005-01-01
The LEP2 data set on the Bhabha process is analyzed with the aim to detect the signals of the heavy virtual Z' gauge bosons. The state interacting with the left-handed standard-model doublets and called the Chiral Z' is investigated. This particle was introduced already as the low-energy state allowed by the renormalizability of the model. The contribution of the Chiral Z' state to the Bhabha process is described by two parameters: the coupling to electrons and the Z-Z' mixing angle. The sign...
Kinematic Fit for the Radiative Bhabha Calibration of BaBar's Electromagnetic Calorimeter
Bauer, Johannes M.
2000-01-01
For the radiative Bhabha calibration of BaBar's electromagnetic calorimeter, the measured energy of a photon cluster is being compared with the energy obtained via a kinematic fit involving other quantities from that event. The details of the fitting algorithm are described in this note, together with its derivation and checks that ensure that the fitting routine is working properly.
Kademani, B. S.; Surwase, Ganesh; Anil Sagar, *; Lalit Mohan; Gaderao, C. R.; Anil Kumar; Kalyane, V. L.; Prakasan, E.R.; Vijai Kumar, *
2005-01-01
Scientrometric analysis of 1733 papers published by the teams comprising total of 926 participating scientists at Chemistry Division of Bhabha Atomic Research Centre (BARC) during 1970-1999 in the domains: Radiation & Photochemistry and Chemical Dynamics (649), Solid State Studies (558), Inorganic, Structural and Materials Chemistry (460) and Theoretical Chemistry (66) were analysed for yearwise productivity, authorship pattern and collaboration. The highest number of publicationsin a year we...
International Nuclear Information System (INIS)
Computational structural analysis of nuclear reactor components requires high speed computing systems. Parallel processing systems, such as ANUPAM developed at Bhabha Atomic Research Centre, have helped immensely in meeting this requirement. The implementation of structural integrity analysis code on ANUPAM is illustrated here by commissioning two in house codes TABS and FAIR. The parallelization strategies and the efficiency of ANUPAM are highlighted. (author). 6 refs., 3 figs
Homi Jehangir Bhabha as a Knowledge Generating System: A Longitudinal Cognition Study
Swarna, T.; Kalyane, V. L.; Prakasan, E. R.; Kumar, Vijai
2003-01-01
Quantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha first quinquennium and fifth quinquennium of his research career had low Self-references; third quinquennium and fourth quinquennium had moderate Self-references; whereas second quinquennium had highest Self-references. The two major...
Model-independent search for the Abelian Z' boson in the Bhabha process
Gulov, A. V.; Skalozub, V. V.
2004-01-01
Model-independent observables to pick out the Abelian Z' signal in the Bhabha process are introduced at energies >= 200 GeV. They measure separately the Z'-induced vector and axial-vector four-fermion contact couplings. The analysis of the LEP2 data constrains the value of the Z'-induced vector four-fermion coupling at the 2-sigma confidence level that corresponds to the Abelian Z' boson with the mass of order 1 TeV.
Kademani, B. S.; Vijai Kumar, *; Anil Kumar; Anil Sagar, *; Lalit Mohan; Surwase, Ganesh; Gaderao, C. R.
2005-01-01
Attempts to analyse quantitatively 475 papers published by the Bio-Organic Division of Bhabha Atomic Research Centre during 1972–2002 in various domains like Synthesis (202), Bioorganic Chemistry (100), Biotechnology (70), Natural Products (53), Waste Management (30), Supra-molecular Chemistry (18) and Organic Spectroscopy (2). The highest number of publications in a year were 38 in 2001. The average number of publications per year was 15.3 and the highest collaboration coefficient 1.0 was fo...
Air-Cleaning Operational Experience in the Bhabha Atomic Research Centre, Trombay
International Nuclear Information System (INIS)
The details of the operational experience gathered in the Bhabha Atomic Research Centre on various aspects of the problem associated with the control of pollutants from the operation of nuclear facilities housed therein form the subject of this report. A short account of the standards for radioactive gaseous waste management and the general practices concerning the prevention and control of air contamination is given. Studies on airborne radioactivity and the operational experience of the ventilation systems connected with some of the installations at Trombay are reviewed. The cost aspects of a typical ventilation system of an operating plant are presented. (author)
Energy Technology Data Exchange (ETDEWEB)
Sailer, Andre Philippe
2009-04-15
The International Linear Collider (ILC) is an electron-positron-collider with a variable center-of-mass energy {radical}(2) between 200 and 500 GeV. The small bunch sizes needed to reach the design luminosity of L{sub Peak}=2.10{sup 34} cm{sup -2}s{sup -1} necessary for the physics goals of the ILC, cause the particles to radiate beamstrahlung during the bunch crossings. Beamstrahlung reduces the center-of-mass energy from its nominal value to the effective center-of-mass energy {radical}(2'). The spectrum of the effective center-of-mass energy {radical}(2') is the differential luminosity dL/d{radical}(2'), which has to be known to precisely measure particle masses through threshold scans. The differential luminosity can be measured by using Bhabha events. The real differential luminosity is simulated by the GuineaPig software. The energy spectrum of the Bhabha events is measured by the detector and compared to the energy spectrum of Monte Carlo (MC) Bhabha events with a known differential luminosity given by an approximate parameterization. The parameterization is used to assign each MC event a weight. By re-weighting the events, until the energy spectra from the real and the MC Bhabha events match, the differential luminosity can be measured. The approximate parameterization of the differential luminosity is given by the Circe parameterization introduced by T. Ohl (1997), which does not include the correlation between the particle energies due to beamstrahlung. The Circe parameterization is extended to include the correlation and better describe the differential luminosity. With this new parameterization of the differential luminosity it is possible to predict the observed production cross section of a MC toy particle with a mass of 250 GeV/c{sup 2} to a precision better than 0.2%. Using the re-weighting fit with the extended parameterization also allows the measurement of the beam energy spreads of {sigma}{sub E}=0.0014 for electrons and {sigma
Fourth order wave equation in Bhabha-Madhavarao spin-$\\frac{3}{2}$ theory
Markov, Yu A; Bondarenko, A I
2016-01-01
Within the framework of the Bhabha-Madhavarao formalism, a consistent approach to the derivation of a system of the fourth order wave equations for the description of a spin-$\\frac{3}{2}$ particle is suggested. For this purpose an additional algebraic object, the so-called $q$-commutator ($q$ is a primitive fourth root of unity) and a new set of matrices $\\eta_{\\mu}$, instead of the original matrices $\\beta_{\\mu}$ of the Bhabha-Madhavarao algebra, are introduced. It is shown that in terms of the $\\eta_{\\mu}$ matrices we have succeeded in reducing a procedure of the construction of fourth root of the fourth order wave operator to a few simple algebraic transformations and to some operation of the passage to the limit $z \\rightarrow q$, where $z$ is some (complex) deformation parameter entering into the definition of the $\\eta$-matrices. In addition, a set of the matrices ${\\cal P}_{1/2}$ and ${\\cal P}_{3/2}^{(\\pm)}(q)$ possessing the properties of projectors is introduced. These operators project the matrices ...
Low and medium energy standard X-Ray calibration facility in Bhabha Atomic Research Centre
International Nuclear Information System (INIS)
Due to increased use of radioisotopes in medical, industrial, R and D etc., applications, the need of radiation protection level instruments has increased many folds. Type testing of newly developed instruments is essential before their routine use. Depending on intended photon energy range specified by manufacturer, the evaluation of energy response characteristics of the instrument requires International Organization for Standardization (ISO) recommended for low and medium X-ray beam qualities. Also type testing as per international standards provides confidence, traceability in measurements and to ascertain healthy operating condition of these instruments for their intended long time use. Calibration of radiation monitoring instruments at low and medium energy X-ray is presently carried out only at the national apex laboratory (Bhabha Atomic Research Centre in India). The beam qualities and measurement techniques are available as per recommendations of ISO 4037 and International Atomic Energy Agency (IAEA) Safety Report Series 16. Present paper is intended to provide information about the low and medium energy standard X-ray calibration facility available at Radiation Standards Section, Radiological Physics and Advisory Division, Bhabha Atomic Research Centre for radiation field users and instrument manufacturers/developers to avail this facility
Use of radiation in grain legume improvement at Bhabha Atomic Research Centre
International Nuclear Information System (INIS)
Pulses are the cheapest source of protein for the predominantly vegetarian population of India. However per capita availability of pulses is reduced due to high growth of population and only marginal increase in pulses production. Development of varieties resistant to biotic and abiotic stresses will help to increase and stabilize pulse production in the country. Research work for the improvement of the three important pulse crops namely pigeon pea, mungbean and black gram was initiated using induced mutation approaches in early 70' and recently for cowpea and soybean at the Nuclear Agriculture and Biotechnology Division of the Bhabha Atomic Research Centre, Mumbai. The programme for developing disease resistant high yielding varieties is being pursued at NABTD, BARC using induced mutations and conventional breeding approaches
Development of neutron detectors and neutron radiography at Bhabha Atomic Research Centre
Indian Academy of Sciences (India)
A M Shaikh
2008-10-01
Design and development of neutron detectors and R&D work in neutron radiography (NR) for non-destructive evaluation are important parts of the neutron beam and allied research programme of Solid State Physics Division (SSPD) of Bhabha Atomic Research Centre (BARC). The detectors fabricated in the division not only meet the in-house requirement of neutron spectrometers but also the need of other divisions in BARC, Department of Atomic Energy units and some universities and research institutes in India and abroad for a variety of applications. The NR facility set up by SSPD at Apsara reactor has been used for a variety of applications in nuclear, aerospace, defense and metallurgical industries. The work done in the development of neutron detectors and neutron radiography is reported in this article.
Realizing vision of Dr. Homi Bhabha - first stage of nuclear power programme
International Nuclear Information System (INIS)
Full text: Dr. Homi Bhabha had a vision to harness nuclear energy for peaceful uses of mankind. Considering typical nuclear resources in the country, Dr Bhabha conceptualized the three stage nuclear power programme and gave a road map for its implementation. The robustness of the vision is such that the programme has not undergone a change in last five decades. The first stage of the three-stage programme, based on natural uranium fuelled Pressurised Heavy Water Reactors (PHWRs) has been precursor to the nuclear power programme in India. This paper describes the developments in the last five decades. The establishment of research laboratories and reactors, training school for the manpower needs, industrial infrastructure and establishment of regulatory framework are briefly described. Setting up of first nuclear power reactor in the country as turnkey project and experience on operation of these reactors in India are discussed. The learning phase consisting of setting up of first PHWR in technical collaboration with Canada and design of 220 MWe PHWRs for MAPS is described. The safety features consistent with development of nuclear power globally were incorporated in Narora design and this became a standardized 220 MWe reactor of which many PHWRs of 220 MWe were set up. The experiences with operation of these small size reactors leading to internationally best operational experience in the year 2002 are discussed. The efforts of plant life extension, in-core maintenance jobs and other renovation and modernization jobs are discussed. The increase in unit size of 540 MWe, of which two reactors have been already set up, is explained in detail. The economies of scale demanded increase in the unit size and design of 700 MWe PHWR has been established and the salient features of this design are also discussed in detail. Eight reactors of 700 MWe each would complete the first stage of about 10,000 MWe PHWR programme and plans for setting up of these reactors are discussed
Plant Species Diversity along an Altitudinal Gradient of Bhabha Valley in Western Himalaya
Institute of Scientific and Technical Information of China (English)
Amit Chawla; S. Rajkumar; K.N. Singh; Brij Lal; R.D. Singh; A. K. Thukral
2008-01-01
The present study highlights the rich species diversity of higher plants in the Bhabha Valley of western Himalaya in India. The analysis of species diversity revealed that a total of 313 species of higher plants inhabit the valley with a charactersfic of moist alpine shrub vegetation. The herbaceous life forms dominate and increase with increasing altitude. The major representations are from the families Asteraceae, Rosaceae, Lamiaceae and Poaceae, suggesting thereby the alpine meadow nature of the study area. The effect of altitude on species diversity displays a hump-shaped curve which may be attributed to increase in habitat diversity at the median ranges and relatively less habitat diversity at higher altitudes. The anthropogenic pressure at lower altitudes results in low plant diversity towards the bottom of the valley with most of the species being exotic in nature. Though the plant diversity is less at higher altitudinal ranges, the uniqueness is relatively high with high species replacement rates. More than 90% of variability in the species diversity could be explained using appropriate quantitative and statistical analysis along the altitudinal gradient. The valley harbours 18 threatened and 41 endemic species, most of which occur at higher altitudinal gradients due to habitat specificity.
Causal approach for the electron-positron scattering in Generalized Quantum Electrodynamics
Bufalo, R.; Pimentel, B. M.; Soto, D. E.
2014-01-01
In this paper we study the generalized electrodynamics contribution for the electron-positron scattering process, $e^{-}e^{+}\\rightarrow e^{-}e^{+}$, the Bhabha scattering. Within the framework of the standard model, for energies larger when compared to the electron mass, we calculate the cross section expression for the scattering process. This quantity is usually calculated in the framework of the Maxwell electrodynamics and, by phenomenological reasons, corrected by a cut-off parameter. On...
International Nuclear Information System (INIS)
Activities at Bhabha Atomic Research Centre (BARC), Mumbai, cover nuclear fuel cycle operations based on natural uranium as the fuel. The facilities include: plant for purification and production of nuclear grade uranium metal, fuel fabrication, research reactor operation, fuel reprocessing and radioactive waste management in each stage. Comprehensive radiation protection programmes for assessment and monitoring of radiological impact of these operations, both in occupational and public environment, have been operating in BARC since beginning. These programmes, based on the 1990 ICRP Recommendations as prescribed by national regulatory body, the Atomic Energy Regulatory Board (AERB), are being successfully implemented by the Health, Safety and Environment Group, BARC. Radiation Hazards Control Units attached to the nuclear fuel cycle facilities provide radiation safety surveillance to the various operations. The radiation monitoring programme consists of measurement and control of external exposures by thermoluminescent dosimeters (TLDs), hand-held and installed instruments, and internal exposures by bioassay and direct whole body counting using shadow shield counter for beta gamma emitters and phoswich detector based system for plutonium. In addition, an environmental monitoring programme is in place to assess public exposures resulting from the operation of these facilities. The programme involves analysis of various matrices in the environment such as bay water, salt, fish, sediment and computation of resulting public exposures. Based on the operating experience in these plants, improved educating and training programmes for plant operators, have been designed. This, together with the application of new technologies have brought down individual as well as average doses of occupational workers. The environmental releases remain a small fraction of the authorised limits. The operating health physics experience in some of these facilities is discussed in this paper
The Causal approach for the electron-positron scattering in the Generalized Quantum Electrodynamics
Bufalo, R; Soto, D E
2014-01-01
In this paper we study the generalized electrodynamics contribution for the electron-positron scattering process, $e^{-}e^{+}\\rightarrow e^{-}e^{+}$, the Bhabha scattering. Within the framework of the standard model, for energies larger when compared to the electron mass, we calculate the cross section expression for the scattering process. This quantity is usually calculated in the framework of the Maxwell electrodynamics and, by phenomenological reasons, corrected by a cut-off parameter. On the other hand, by considering the generalized electrodynamics instead of Maxwell's, we can show that the effects played by the Podolsky mass is actually a natural cut-off parameter for this scattering process. Furthermore, by means of experimental data of Bhabha scattering we will estimate its lower bound value. Nevertheless, in order to have a mathematically well defined description of our study we shall present our discussion in the framework of the Epstein-Glaser causal theory.
International Nuclear Information System (INIS)
The experiment we have performed on the ACO (Orsay Collider Ring) is one of the most accurate tests of quantum electrodynamics over very short interaction distances (10-14 cm). We have studied the electron-positron elastic scattering at very wide angle. This work is divided into 4 parts. The first part reviews recent tests of quantum electrodynamics and presents the electron-positron elastic scattering. The second part describes the measurement of brightness: the experimental device, data analysis and accuracy. The measurement of brightness has been performed by detecting the photons emitted in the double Bremsstrahlung reaction: e+e- → e+e-γγ. The third part deals with the measurement of the number of Bhabha events. The last part compares the experimental value of the Bhabha scattering with the theoretically expected value. We have got the following results: the number of Bhabha events: 757 events, the experimental value for Bhabha scattering cross-section: [1.97 ± 0.09 (stat.) ± 0.10 (syst.)]*10-31 cm2. The comparison of this experimental value with the expected value has allowed us to set the lower limit of the cutting parameter Λ: Λ > 2 GeV
Investigation of anomalous spectral structure in low-energy positron scattering
International Nuclear Information System (INIS)
Scattering of low-energy positrons on a thorium target has been investigated. The positron-electron energy spectrum in the interval 265-425 keV is best described in terms of Bhabha scattering with the addition of a small peak at about 330 keV for both the positrons and the electrons. The evidence for this peak is not considered conclusive. (author)
Directory of Open Access Journals (Sweden)
Susan E. Sterrett
2015-10-01
Full Text Available Homi K. Bhabha is a post-colonial and cultural theorist who describes the emergence of new cultural forms from multiculturalism. When health profession students enculturated into their profession discuss patient care in an interprofessional group, their unilateral view is challenged. The students are in that ambiguous area, or Third Space, where statements of their profession’s view of the patient enmesh and an interprofessional identity begins to form. The lessons learned from others ways of assessing and treating a patient, seen through the lens of hybridity allow for the development of a richer, interprofessional identity. This manuscript will seek out the ways Bhabha’s views of inbetweenness enhance understanding of the student’s development of an interprofessional viewpoint or identity, and deepen the author’s developing framework of an Interprofessional Community of Practice.
Neural network predictions for Z' boson within LEP2 data set of Bhabha process
Buryk, A. N.; Skalozub, V. V.
2008-01-01
The neural network approach is applied to search for the Z'-boson within the LEP2 data set for e+ e- -> e+ e- scattering process. In the course of the analysis, the data set is reduced by 20 percent. The axial-vector and vector couplings of the Z' are estimated at 95 percent CL within a two-parameter fit. The mass is determined to be 0.53-1.05 TeV. Comparisons with other results are given.
Research within the coordinated programme on neutron scattering techniques in applied research
International Nuclear Information System (INIS)
This paper reviews developments of neutron scattering studies at Bhabha Atomic Research Centre (BARC) over the past two decades through utilisation of Apsara and Circus reactor facilities. Salient results in neutron crystallography, magnetic diffraction and inelastic neutron scattering will be presented highlighting progressive involvement in more and more complex studies. The growth of non-neutronic activities as a natural outcome of overall necessity and interest of investigators will be indicated. A description of facilities planned at R5 and the nature of studies that are likely to be taken up at R5 will be briefly discussed. (author)
International Nuclear Information System (INIS)
Measurement of the ambient radiation level in the surroundings of any nuclear facility is necessary to ensure the regulation and control over the environmental releases and any possible radiological impact. This is achieved in Bhabha Atomic Research Centre Trombay site using various monitoring methodologies, different Dose Logging Equipments including Radiation Early Warning System and other passive devices. During the present study (October 2009 to September 2010), external exposures due to atmospheric dispersion of 41Ar, released from Cirus and Dhruva reactors (maximum cumulative release rate 8.27E+8 Bq.s-1) were assessed by installing Gamma tracers and TLDs at different monitoring locations. TLDs were used for the measurement of cumulative environmental doses for a longer period and Gamma tracer is primarily used for dose rate measurement with provision of dose assessment of any desired period
International Nuclear Information System (INIS)
The Bhabha Atomic Research Centre has participated in the 8th, 9th and 10th summer expeditions to Antarctica during 1988-91 period to carry out background radiation survey and to collect representative samples for radioactivity and heavy metal analyses. Spot measurements of ions as well as Radon daughter radionuclides were also carried out during the expeditions. Radon levels as well as heavy metal pollutant concentrations have been found to be quite low in general; however higher levels were observed at places where human activity is concentrated around the landing area as well as the laboratory site. The richness of the shelf waters at Antarctic were also realised through analysis of phytoplankton and zooplankton samples. (author). 25 refs., 5 figs., 26 tabs
Energy Technology Data Exchange (ETDEWEB)
Kostorz, G. [Eidgenoessische Technische Hochschule, Angewandte Physik, Zurich (Switzerland)
1996-12-31
While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs.
International Nuclear Information System (INIS)
While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs
International Nuclear Information System (INIS)
The central air conditioning plant (CAP) of Bhabha Atomic Research Centre (BARC) uses raw water from Mumbai Mahanagar Palika (MMP) for its condenser cooling purposes. The same raw water is also used for drinking purposes. In an effort to minimize the dependency of raw water from MMP the CAP authorities felt a need for locating an alternate source of usable raw water. In this context it was decided to use water from the nearby bore wells located within CAP premises near the coast. The CAP site is located [19 deg 30' N, 72 deg 6' E] on the slope between the lush green Trombay hills and Mumbai Harbor Bay (MHB), resulting in the outflow of the most of the rainwater into MHB. However, part of the rainfall seeps into the subsurface resulting in the availability of groundwater through the bore wells located on the coast. The location of the bore wells close to the sea coast (∼ 200 metres away from high tide line of the highly polluted MHB), in the middle of the lush green zone, raised a question on the possible intrusion of seawater into the groundwater and its adverse impact on the operational practices of CAP. In this connection there was a need to evaluate the water from three bore wells for their use as coolant water at CAP. This report reveals the detailed study carried out on the physico-chemical nature of the water from the bore wells, for two years and the implications of these findings on operational practices of CAP. In addition environmental isotope (2H, 8O and 3H) study was also carried out to substantiate the findings of physico-chemical study. These studies revealed interesting features. Groundwater quality in this site is mainly influenced by precipitation and rock- water interaction. The minerals present in the Basalt rocks are the source materials for the dominant ions (Ca2+, Mg2+ and HCO3-) observed in the waters of bore well no 1 and 3, whereas high sodium in ground water from bore well no 2 may be due to ion exchange process. Characteristic ionic
International Nuclear Information System (INIS)
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs
Energy Technology Data Exchange (ETDEWEB)
Stirling, W.G. [Liverpool Univ., Dep. of Physics, Liverpool (United Kingdom); Perry, S.C. [Keele Univ. (United Kingdom). Dept. of Physics
1996-12-31
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO{sub 3} is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs.
Polarized electron-positron scattering and annihilation in the Salam-Weinberg model
International Nuclear Information System (INIS)
In this thesis the lepton-antilepton scattering respectively production in the Salam-Weinberg model is treated. Thereby in the initial state arbitrary lepton-antilepton pairs and in the final state arbitrary fermion-antifermion pairs are permitted. The calculations have been performed analytically and beyond this with the symbol processing (non-numerical) code SCHOONSCHIP. Thereby topics were regarded in comparison to the calculations hitherto present: i) The particles are in the initial and final state arbitrarily polarized. ii) No high-energy approximation is made. iii) All contributions of the fields characteristic for the Salam-Weinberg model are regarded. iv) Beside the resonance widths also the Ksub(μ)Ksub(ν) terms in the propagators for the vector fields are fully included in the calculations. v) The scattering plane and the laboratory plane can be mutually oriented arbitrarily. From the manifold of the scattering processes which can be described by these formulas only Bhabha scattering and lepton pair production in e+e- interactions are numerically evaluated and discussed. As typical example for the production of the up quarks the canti c production and for the production of the down quarks the banti b production is treated. The evaluation was performed for three different energies, different degrees of polarization and configurations, and different orientations of the scattering plane relatively to the laboratory plane. (orig./HSI)
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
International Nuclear Information System (INIS)
Written by the author of the widely acclaimed textbook. Theoretical Atomic Physics Includes sections on quantum reflection, tunable Feshbach resonances and Efimov states. Useful for advanced students and researchers. This book presents a concise and modern coverage of scattering theory. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. The level of abstraction is kept as low as at all possible, and deeper questions related to mathematical foundations of scattering theory are passed by. The book should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. It is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
International Nuclear Information System (INIS)
The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research
International Nuclear Information System (INIS)
The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
On scattered subword complexity
Kása, Zoltán
2011-01-01
Special scattered subwords, in which the gaps are of length from a given set, are defined. The scattered subword complexity, which is the number of such scattered subwords, is computed for rainbow words.
Imaging with Scattered Neutrons
Ballhausen, H; Gähler, R; Trapp, M; Van Overberghe, A
2006-01-01
We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.
Bidirectional optical scattering facility
Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI) The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from...
Early Years of Neutron Scattering and Its Manpower Development in Indonesia
International Nuclear Information System (INIS)
In this paper I shall give a short history of the development of neutron scattering at the Research Centre for Nuclear Techniques (PPTN), in Bandung, and the early development of a more advanced facilities at the Neutron Scattering Laboratory (NSL BATAN), Centre of Technology for Nuclear Industrial Materials, in Serpong. The first research reactor in Indonesia was the TRIGA MARK II in Bandung, which became operational in 1965, with a power of 250 KW, upgraded to 1 MW in 1971, and to 2 MW in 2000. The neutron scattering activities was started in 1967, with the design and construction of the first powder diffractometer, and put in operation in 1970. It was followed by the second instrument, the filter detector spectrometer built in 1975 in collaboration with the Bhabha Atomic Research Centre (BARC), India. A powder diffractometer for magnetic studies was built in 1980, and finally, a modification of the filter detector spectrometer to measure textures was made in 1986. A brief description of the design and construction of the instruments, and a highlight of some research topics will be presented. Early developments of neutron scattering activities at the 30 MW, RSG-GAS reactor in Serpong in choosing suitable research program, which will be mainly centred around materials testing/characterization, and materials/condensed matter researches has been agreed. Instrument planning and layout which were appropriate to carry out the program had been decided. Manpower development for the neutron scattering laboratory is a severe problem. The efforts to overcome this problem has been solved. International Cooperation through workshops and on the job trainings also support the supply of qualified manpower
Early Years of Neutron Scattering and Its Manpower Development in Indonesia
Marsongkohadi
2008-03-01
In this paper I shall give a short history of the development of neutron scattering at the Research Centre for Nuclear Techniques (PPTN), in Bandung, and the early development of a more advanced facilities at the Neutron Scattering Laboratory (NSL BATAN), Centre of Technology for Nuclear Industrial Materials, in Serpong. The first research reactor in Indonesia was the TRIGA MARK II in Bandung, which became operational in 1965, with a power of 250 KW, upgraded to 1 MW in 1971, and to 2 MW in 2000. The neutron scattering activities was started in 1967, with the design and construction of the first powder diffractometer, and put in operation in 1970. It was followed by the second instrument, the filter detector spectrometer built in 1975 in collaboration with the Bhabha Atomic Research Centre (BARC), India. A powder diffractometer for magnetic studies was built in 1980, and finally, a modification of the filter detector spectrometer to measure textures was made in 1986. A brief description of the design and construction of the instruments, and a highlight of some research topics will be presented. Early developments of neutron scattering activities at the 30 MW, RSG-GAS reactor in Serpong in choosing suitable research program, which will be mainly centred around materials testing/characterization, and materials/condensed matter researches has been agreed. Instrument planning and layout which were appropriate to carry out the program had been decided. Manpower development for the neutron scattering laboratory is a severe problem. The efforts to overcome this problem has been solved. International Cooperation through workshops and on the job trainings also support the supply of qualified manpower.
International Nuclear Information System (INIS)
The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)
International Nuclear Information System (INIS)
The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
International Nuclear Information System (INIS)
The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)
Imaging with Scattered Neutrons
Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M; Van Overberghe, A.
2006-01-01
We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...
Kouri, Donald J
2017-01-01
This book provides a detailed exposition of quantum scattering theory as applied to chemical physics. It includes the fundamental mathematics of scattering, details of how it applies to atom-molecule, molecule-molecule collisions, as well as collisions with surfaces. A variety of computational methods for solving scattering problems are presented. In addition, some discussion of fully quantal approximations is included. Both inelastic and reactive scattering are treated in detail. Both time-dependent and time-independent approaches to scattering theory and scattering computation are included. The book will reflect the research done over approximately 50 years by the author.
Andersson, N
2000-01-01
This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.
Roessli, B.; Böni, P.
2000-01-01
The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.
International Nuclear Information System (INIS)
The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)
Borie, E.
2012-01-01
A recent proposal to measure the proton form factor by means of muon-proton scattering will use muons which are not ultrarelativistic (and also not nonrelativistic). The usual equations describing the scattering cross section use the approximation that the scattered lepton (usually an electron) is ultrarelativistic, with v/c approximately equal to 1. Here the cross section is calculated for all values of the energy. It agrees with the standard result in the appropriate limit.
Introduction to neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Fischer, W.E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1996-11-01
We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.
Energy Technology Data Exchange (ETDEWEB)
Futterman, J.A.H.; Handler, F.A.; Matzner, R.A.
1987-01-01
This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging.
International Nuclear Information System (INIS)
This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging
Partially strong WW scattering
International Nuclear Information System (INIS)
What if only a light Higgs boson is discovered at the CERN LHC? Conventional wisdom tells us that the scattering of longitudinal weak gauge bosons would not grow strong at high energies. However, this is generally not true. In some composite models or general two-Higgs-doublet models, the presence of a light Higgs boson does not guarantee complete unitarization of the WW scattering. After partial unitarization by the light Higgs boson, the WW scattering becomes strongly interacting until it hits one or more heavier Higgs bosons or other strong dynamics. We analyze how LHC experiments can reveal this interesting possibility of partially strong WW scattering.
Multiple scattering tomography.
Modregger, Peter; Kagias, Matias; Peter, Silvia; Abis, Matteo; Guzenko, Vitaliy A; David, Christian; Stampanoni, Marco
2014-07-11
Multiple scattering represents a challenge for numerous modern tomographic imaging techniques. In this Letter, we derive an appropriate line integral that allows for the tomographic reconstruction of angular resolved scattering distributions, even in the presence of multiple scattering. The line integral is applicable to a wide range of imaging techniques utilizing various kinds of probes. Here, we use x-ray grating interferometry to experimentally validate the framework and to demonstrate additional structural sensitivity, which exemplifies the impact of multiple scattering tomography. PMID:25062159
Modelling Hyperboloid Sound Scattering
DEFF Research Database (Denmark)
Burry, Jane; Davis, Daniel; Peters, Brady; Ayres, Phil; Klein, John; Pena de Leon, Alexander; Burry, Mark
The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...... both physical and digital models at three distinct scales. The results suggest hyperboloid geometry, while difficult to fabricate, facilitates sound scattering....
Neutron scattering by ferroelectrics
Aksenov, V; Stamenkovic, S
1989-01-01
This book presents the recent theoretical and experimental developments of neutron scattering by ferroelectrics. A Model description of lattice dynamics of structurally unstable crystals (self-consistent phonon approximation, pseudo-spin formalism, coherent potential approximation etc.) is formulated. The effects of nonlinear excitations and lattice defects in neutron scattering are also discussed.
Neutron scattering from fractals
DEFF Research Database (Denmark)
Kjems, Jørgen; Freltoft, T.; Richter, D.;
1986-01-01
-angle neutron scattering studies of the variation with aggregation rate are presented. These results allow a very detailed comparison to be made with the theoretical scattering curves. Preliminary incoherent inelastic data on the low-frequency dynamics of hydroxylated silica particle aggregates show a clear...
Neutron scattering from fractals
DEFF Research Database (Denmark)
Kjems, Jørgen; Freltoft, T.; Richter, D.; Sinha, S. K.
-angle neutron scattering studies of the variation with aggregation rate are presented. These results allow a very detailed comparison to be made with the theoretical scattering curves. Preliminary incoherent inelastic data on the low-frequency dynamics of hydroxylated silica particle aggregates show a clear...
Introductory theory of neutron scattering
International Nuclear Information System (INIS)
The paper comprises a set of six lecture notes which were delivered to the summer school on 'Neutron Scattering at a pulsed source', Rutherford Laboratory, United Kingdom, 1986. The lectures concern the physical principles of neutron scattering. The topics of the lectures include: diffraction, incoherent inelastic scattering, connection with the Schroedinger equation, magnetic scattering, coherent inelastic scattering, and surfaces and neutron optics. (UK)
Scattering of periodic solitons
Cova, R J
2003-01-01
With the help of numerical simulations we study N-soliton scattering (N=3,4) in the (2+1)-dimensional CP^1 model with periodic boundary conditions. When the solitons are scattered from symmetrical configurations the scattering angles observed agree with the earlier \\pi/N predictions based on the model on R_2 with standard boundary conditions. When the boundary conditions are not symmetric the angles are different from \\pi/N. We present an explanation of our observed patterns based on a properly formulated geodesic approximation.
Scattering from Electroweak Strings
Lo, Hoi-Kwong
1994-01-01
The scattering of a charged fermion from an electroweak string is studied. Owing to an amplification of the wave function at the core radius, the cross sections for helicity flip processes can be largely enhanced. For $0
Environment scattering in GADRAS.
Energy Technology Data Exchange (ETDEWEB)
Thoreson, Gregory G.; Mitchell, Dean James; Theisen, Lisa Anne; Harding, Lee T.
2013-09-01
Radiation transport calculations were performed to compute the angular tallies for scattered gamma-rays as a function of distance, height, and environment. Green's Functions were then used to encapsulate the results a reusable transformation function. The calculations represent the transport of photons throughout scattering surfaces that surround sources and detectors, such as the ground and walls. Utilization of these calculations in GADRAS (Gamma Detector Response and Analysis Software) enables accurate computation of environmental scattering for a variety of environments and source configurations. This capability, which agrees well with numerous experimental benchmark measurements, is now deployed with GADRAS Version 18.2 as the basis for the computation of scattered radiation.
International Nuclear Information System (INIS)
We briefly review some of the motivations, early results, and techniques of magnetic elastic and inelastic electron-nucleus scattering. We then discuss recent results, especially those acquired at high momentum transfers. 50 refs., 19 figs
International Nuclear Information System (INIS)
Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)
Applied electromagnetic scattering theory
Osipov, Andrey A
2016-01-01
Besides classical applications (radar and stealth, antennas, microwave engineering), scattering and diffraction are enabling phenomena for some emerging research fields (artificial electromagnetic materials or metamaterials, terahertz technologies, electromagnetic aspects of nano-science). This book is a tutorial for advanced students who need to study diffraction theory. The textbook gives fundamental knowledge about scattering and diffraction of electromagnetic waves and provides some working examples of solutions for practical high-frequency scattering and diffraction problems. The book focuses on the most important diffraction effects and mechanisms influencing the scattering process and describes efficient and physically justified simulation methods - physical optics (PO) and the physical theory of diffraction (PTD) - applicable in typical remote sensing scenarios. The material is presented in a comprehensible and logical form, which relates the presented results to the basic principles of electromag...
DEFF Research Database (Denmark)
Gudel, H. U.; Furrer, A.; Kjems, Jørgen
1986-01-01
Insulating compounds containing dimers of transition metal and rare earth ions have been studied by inelastic neutron scattering (INS). Energy splittings can be directly determined, and the corresponding parameters are easily extracted from the experimental data. The intensities of dimer...
International Nuclear Information System (INIS)
This collection contains 21 papers on the application and development of LIDAR (Light Detection and Ranging) Thomson scattering techniques for the determination of spatially resolved electron temperature and density in magnetic confinement experiments, particularly tokamaks. Refs, figs and tabs
Dremin, I M
2012-01-01
When colliding, the high energy hadrons can either produce new particles or scatter elastically without change of their quantum num- bers and other particles produced. Namely elastic scattering of hadrons is considered in this review paper. Even though the inelastic processes dominate at high energies, the elastic scattering constitutes the notice- able part of the total cross section ranging between 18 and 25% with some increase at higher energies. The scattering proceeds mostly at small angles and reveals peculiar dependences at larger angles disclos- ing the geometrical structure of the colliding particles and di?erent dynamical mechanisms. The fast decreasing Gaussian peak at small angles is followed by the exponential (Orear) regime with some shoul- ders and dips and then by the power-like decrease. Results of various theoretical approaches are compared with exper- imental data. Phenomenological models pretending to describe this process are reviewed. The unitarity condition requires the exponen- tial re...
International Nuclear Information System (INIS)
We consider the scattering theory for the Schroedinger operator -Dx2+V(x) on the graphs made of one-dimensional wires connected to external leads. We derive two expressions for the scattering matrix on arbitrary graphs. One involves matrices that couple arcs (oriented bonds), the other involves matrices that couple vertices. We discuss a simple way to tune the coupling between the graph and the leads. The efficiency of the formalism is demonstrated with a few known examples. (author)
Catastrophes in surface scattering
International Nuclear Information System (INIS)
Theoretical and experimental studies concerning atom-surface interactions in the energy range from hyperthermal to approximately 100 eV are reported. An extended study of the interaction of low energetic alkalis (sodium and potassium) with a silver crystal is presented. Finally the ultimate experimental result in this research, the first observation of catastrophes in surface scattering, is shown. The results clearly indicate the strength of the catastrophe analysis in gas-surface scattering. 218 refs.; 40 figs.; 170 schemes; 4 tabs
Watson, Greg
1996-01-01
Neutron Compton scattering measurements have the potential to provide direct information about atomic momentum distributions and adiabatic energy surfaces in condensed matter. First applied to measuring the condensate fraction in superfluid helium, the technique has recently been extended to study a variety of classical and quantum liquids and solids. This article reviews the theoretical background for the interpretation of neutron Compton scattering, with emphasis on studies of solids.
Polarized Proton Nucleus Scattering
Kopeliovich, B. Z.; Trueman, T. L.
2000-01-01
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
DEFF Research Database (Denmark)
Gudel, H. U.; Furrer, A.; Kjems, Jørgen
Insulating compounds containing dimers of transition metal and rare earth ions have been studied by inelastic neutron scattering (INS). Energy splittings can be directly determined, and the corresponding parameters are easily extracted from the experimental data. The intensities of dimer excitati......Insulating compounds containing dimers of transition metal and rare earth ions have been studied by inelastic neutron scattering (INS). Energy splittings can be directly determined, and the corresponding parameters are easily extracted from the experimental data. The intensities of dimer...
Scattering resonances in graphene
Nazarov, V. U.; Silkin, V. M.; Krasovskii, E. E.
2012-01-01
We address the two-dimensional band-structure of graphene above the vacuum level in the context of discrete states immersed in the three-dimensional continuum. Scattering resonances are discovered that originate from the coupling of the in-plane and perpendicular motions, as elucidated by the analysis of an exactly solvable model. Some of the resonances turn into true bound states at high-symmetry $\\kv$ vectors. {\\it Ab initio} scattering theory verifies the existence of the resonances in rea...
Scattering of periodic solitons
Energy Technology Data Exchange (ETDEWEB)
Cova, R.J. [Carleton University, School of Mathematics and Statistics, 1125 Colonel by Drive, Ottawa, Ontario K1S 5B6 (Canada); Zakrzewski, W.J. [University of Durham, Dept. of Mathematical Sciences, Durham DH1 3LE (United Kingdom)]. e-mail: rcova@math.carleton.ca
2004-07-01
Through numerical simulations we study N-soliton scattering (N = 3, 4) in the (2 + 1)-dimensional CP{sup 1} model with periodic boundary conditions. Solitons colliding from symmetrical configurations scatter at {pi}/ N, as observed in the usual model with standard boundary conditions. When the initial configurations are not symmetric the angles differ from {pi}/ N. We describe our observed patterns based on a properly formulated geodesic approximation. (Author) 11 refs., 10 figs.
International Nuclear Information System (INIS)
The theory of stimulated Thomson scattering is investigated both quantum mechanically and classically. In the interaction of a collisionless plasma with two electromagnetic waves, both with frequencies well above the plasma frequency, energy is transferred from the high-frequency wave to the low-frequency wave via stimulated Thomson scattering. This process is mediated by the nonlinear interaction of the plasma electrons with a beat wave at the difference frequency between the two waves; this beat frequency must be well above the plasma frequency. The gain coefficient for stimulated Thomson scattering is calculated both quantum mechanically and classically, and identical results are obtained. The classical calculation also yields the first nonlinear term in the index of refraction due to stimulated Thomson scattering, as well as the details of the saturation of the gain and the index of refraction. The authors present explicit formulas for the gain coefficient and the index of refraction, in the unsaturated limit, for both very cold and very hot plasmas. The calculations indicate that it should be possible to detect stimulated Thomson scattering experimentally by means of polarization enhancement. In an appendix, the theory of stimulated Thomson scattering is used to treat the free-electron amplifier
Electron scattering from atoms
International Nuclear Information System (INIS)
Methods for electron scattering fall into two main classes : coupled channels methods involve an expansion of the total wave function in target eigenstates; R-matrix methods use a CI expansion for the whole electron-plus-target problem in a finite region of space outside which the electron feels no potential (or only the residual Coulomb potential in the case of charged targets). This problem has no continuum. It has discrete states with arbitrarily-high energies. The wave functions for the finite-range problem are matched to the known external wave functions at the boundary. Experimental data from studies on electron-hydrogen scattering, electron sodium scattering, electron scattering to singlet and triplet states of helium and electron scattering to and from magnesium are reviewed. The coupled-channels-optical model, coupled-channels with ad hoc pseudostates, and R-matrix theory are complete calculations in that no aspects of scattering are omitted, although approximations are of course made. The methods are in at least semi-quantitative agreement with each other where comparison is possible. Experiments in general are in agreement with each other. However for all atoms there are significant disagreements between theory and experiment for small differential cross sections. Total cross sections agree quite well
Proton inelastic scattering cannot be predicted from electron scattering results
International Nuclear Information System (INIS)
The prediction of proton inelastic scattering based on transition densities determined from electron scattering is critically examined. As an example, for the O3+ state in 16O, it is shown that abnormal parity amplitudes prevent an unambiguous prediction, and largely different results can be found for proton scattering while electron scattering results are identical
Schaetzel, Klaus
1989-08-01
Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.
Neutron scattering at high pressure
Mcwhan, D.B.
1984-01-01
The techniques to do elastic and inelastic neutron scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron scattering centres are capable of reaching pressures of the order of 5 GPa (50 kbar), and attempts to reach 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X-ray scattering at high pressure using rotating anode or synchrotron sources.
Instruments for neutron scattering
International Nuclear Information System (INIS)
The wide variety of science that can be presented with neutron scattering essentially boils down to determine two vectors, the momentum k of the neutron before it hits the sample and after it leaves the sample. All experimentally obtainable information is contained in the probability distribution W(k,k') of a neutron to undergo scattering takes it from k to k'. In this paper we will introduce the principles and concepts to understand what one is doing if one perform an experiment on a certain instrument We will describe the components of which almost all neutron scattering instruments are made up and their functions and show how these components can be combined to contribute in the best possible way to the solution of questions in a large number of scientific areas
Quantum Optical Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær
for the dipoles while treating them as quantum two-level systems and using the Born–Markov and rotating-wave approximations. Postponing the rotating-wave approximation to the very end of the formal calculations allows us to identify the different physical parameters of the dipole evolution in terms of...... first part we use a scattering-matrix formalism combined with results from random-matrix theory to investigate the interference of quantum optical states on a multiple scattering medium. We investigate a single realization of a scattering medium thereby showing that it is possible to create entangled...... states by interference of squeezed beams. Mixing photon states on the single realization also shows that quantum interference naturally arises by interfering quantum states. We further investigate the ensemble averaged transmission properties of the quantized light and see that the induced quantum...
Applications of Compton scattering
Institute of Scientific and Technical Information of China (English)
LUO Guang; ZHOU Shang-qi; HAN Zhong; CHEN Shuang-kou
2006-01-01
Compton scattering is used very widely. In this article, we depict an overall picture for its applications which are based on two basic theories. The first is the electron densitometry theory related to electron density. According to this theory its applications are in two fields: one is Compton scatter densitometry (CSD), the other is Compton scatter imaging (CSI). The second technique involves the electron momentum distribution and Compton profile. Applications of this technique are mainly the Compton profile analysis (CPA) and the Compton profile or the electron momentum distribution in physics and chemistry.Future research fields are suggested according to the current situation and limits of this technique and a promising prospect is unfolded.
$\\Lambda$ Scattering Equations
Gomez, Humberto
2016-01-01
The CHY representation of scattering amplitudes is based on integrals over the moduli space of a punctured sphere. We replace the punctured sphere by a double-cover version. The resulting scattering equations depend on a parameter $\\Lambda$ controlling the opening of a branch cut. The new representation of scattering amplitudes possesses an enhanced redundancy which can be used to fix, modulo branches, the location of four punctures while promoting $\\Lambda$ to a variable. Via residue theorems we show how CHY formulas break up into sums of products of smaller (off-shell) ones times a propagator. This leads to a powerful way of evaluating CHY integrals of generic rational functions, which we call the $\\Lambda$ algorithm.
Electron scattering off nuclei
International Nuclear Information System (INIS)
Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author)
Neutron scattering. Experiment manuals
International Nuclear Information System (INIS)
The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
Neutron scattering. Experiment manuals
International Nuclear Information System (INIS)
The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
International Nuclear Information System (INIS)
The coupled-channels-optical method has been implemented using two different approximations to the optical potential. The half-on-shell optical potential involves drastic approximations for numerical feasibility but still gives a good semiquantitative description of the effect of uncoupled channels on electron scattering from hydrogen, helium and sodium. The distorted-wave optical potential makes no approximations other than the weak coupling approximation for uncoupled channels. In applications to hydrogen and sodium it shows promise of describing scattering phenomena excellently at all energies. 27 refs., 5 figs
Neutron scattering. Experiment manuals
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
Scattering with absorptive interaction
Cassing, W.; Stingl, M.; Weiguny, A.
1982-07-01
The S matrix for a wide class of complex and nonlocal potentials is studied, with special attention given to the motion of singularities in the complex k plane as a function of the imaginary coupling strength. Modifications of Levinson's theorem are obtained and discussed. Analytic approximations to the S matrix in the vicinity of narrow resonances are exhibited and compared to numerical results of resonating-group calculations. The problem of defining resonances in the case of complex interactions is discussed, making contact with the usual analysis of scattering in terms of Argand diagrams. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive potentials.
Neutron scattering. Experiment manuals
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2014-07-01
The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
2007-01-01
Low energy ion scattering (LEIS) is the study of the composition and structure of a surface by the detection of low energy ions with energies ranging from 100 eV to 10 keV elastically scattered off the surface. The extreme sensitivity to the outermost atomic layer makes it as a unique tool for surface analysis. In this paper, concepts of shadowing, blocking, and also polar and azimuthal scans have been described. Surface order and surface atom spacings are revealed by using these concepts and...
Inversion assuming weak scattering
DEFF Research Database (Denmark)
Xenaki, Angeliki; Gerstoft, Peter; Mosegaard, Klaus
2013-01-01
The study of weak scattering from inhomogeneous media or interface roughness has long been of interest in sonar applications. In an acoustic backscattering model of a stationary field of volume inhomogeneities, a stochastic description of the field is more useful than a deterministic description...
International Nuclear Information System (INIS)
Techniques to study nonlinear differential difference equations have been developed only in the last few years. These methods use the scattering and inverse scattering transforms to obtain formal solutions to initial value problems. However, analytic questions about the scattering transform have not been dealt with extensively in the literature. In this thesis, the generalized eigenvalue equation (1) Spsi = Jpsi + JQ0psi + Q1Spsi, where psi is a 2 X 2 matrix, J = diag(z,z-1), Q0(Q1) is a strictly lower (upper) triangular 2 x 2 matrix valued summable sequence is studied. This problem is not self adjoint, and is a discretization of the equation studied by Albowitz et al and Beals and Coifman. The notion of a scattering transform is introduced, showing that it is injective, and with proceedings to obtain its analytic properties. It is shown that decay of the potential implies smoothness of the data, and conversely smoothness of the data implies decay of the potential. The data satisfies a symmetry condition along with additional constraints, and it is proved that when these are satisfied, eigenfunctions and potentials can be recovered from the data such that (1) holds. This theory is then applied to obtain a class of nonlinear differential difference evolution equations solvable by this method. How far these results extend to the k x k matrix case is also indicated
Critical scattering by bubbles
International Nuclear Information System (INIS)
We apply the complex angular momentum theory to the problem of the critical scattering of light by spherical cavities in the high frequency limit (permittivity greater than the external media) (e.g, air bubble in water) (M.W.O.)
International Nuclear Information System (INIS)
This corrected and updated second edition of ''Scattering Theory'' presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is kept as low as at all possible and deeper questions related to the mathematical foundations of scattering theory are passed by. It should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. The book is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Energy Technology Data Exchange (ETDEWEB)
Helene Fonvieille
2003-05-01
Virtual Compton Scattering off the proton: {gamma}^+p --> {gamma}p is a new field of investigation of nucleon structure. Several dedicated experiments have been performed at low c.m. energy and various momentum transfers, yielding specific information on the proton. This talk reviews the concept of nucleon Generalized Polarizabilities and the present experimental status.
Energy Technology Data Exchange (ETDEWEB)
Friedrich, Harald [Technische Univ. Muenchen, Garching (Germany). Physik-Department
2016-07-01
This corrected and updated second edition of ''Scattering Theory'' presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is kept as low as at all possible and deeper questions related to the mathematical foundations of scattering theory are passed by. It should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. The book is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Small angle neutron scattering
Directory of Open Access Journals (Sweden)
Cousin Fabrice
2015-01-01
Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of
Small angle neutron scattering
International Nuclear Information System (INIS)
Small Angle Neutron Scattering (SANS) is a technique that enables to probe the 3-D structure of materials on a typical size range lying from about 1 nm up to a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nano-metric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area... ) through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons) make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some information that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer), form factor analysis (I(q→0), Guinier regime, intermediate regime, Porod regime, polydisperse system), structure factor analysis (2. Virial coefficient, integral equations, characterization of aggregates), and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast). It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of spectrometer
Light scattering reviews 8 radiative transfer and light scattering
Kokhanovsky, Alexander A
2013-01-01
Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.
Scattering by a nihility sphere
Lakhtakia, A
2006-01-01
On interrogation by a plane wave, the back-scattering efficiency of a nihility sphere is identically zero, and its extinction and forward-scattering efficiencies are higher than those of a perfectly conducting sphere.
Scattering of Fermions by Gravitons
Ulhoa, S C; Khanna, Faqir C
2016-01-01
The interaction between gravitons and fermions is investigated in the teleparallel gravity. The scattering of fermions and gravitons in the weak field approximation is analyzed. The transition amplitudes of M$\\varnothing$ller, Compton and new gravitational scattering are calculated.
International Nuclear Information System (INIS)
This report on the IAEA Technical Committee Meeting on LIDAR (LIght Detection And Ranging) Thomson Scattering, held at the JET Joint Undertaking, Abingdon, Oxfordshire, United Kingdom, 8-10 April 1991, summarizes reviews of (1) the existing JET LIDAR system; (2) developments in solid state, visible and near IR lasers that are of potential interest for LIDAR applications; (3) possible laser sources, including Excimer and CO2 for their interesting pulse duration and repetition rate if suitable detectors can be found; (4) a compact design for a Nd phosphate glass system; (5) short pulse length (30-50 ps) laser requirements to obtain improved spatial resolution needed for the divertor region plasma in tokamaks; (6) a more advanced laser design using a so-called light boiler and wave front reversal (WFR) cells; (7) possibilities to use Nd:YAG laser wavelengths in a LIDAR system; a session on detectors and analysis methods describing (8) the new Scancross streaking intensifier; (9) detectors for LIDAR Thomson scattering (advantages of streak cameras, photomultipliers, and gated intensifiers); (10) results of investigations into the use of an AGAT streak camera as a possible LIDAR detector; (11) assessment experiments on a Hamamatsu streak camera planned for use on the Large Helical Device (heliotron); (12) studies on the usefulness of microchannel plate photomultipliers as detectors in the JET LIDAR system; (13) conventional Thomson scattering application of microchannel photomultipliers on the reversed-field pinch RFX; (14) a description of the Nd:YLF 10 Hz laser based scattering system for FTU; (15) the feasibility of a 8-10 Hz LIDAR system; (16) some aspects of Raman calibration of scattering systems; (17) use of statistical analysis of data for recovering calibrations of a data set; and, finally, a session on LIDAR systems for future devices, especially (18) ITER and BPX, with ITER requiring development of radiation hard optics capable of withstanding both thermal
Electron scattering for exotic nuclei
Indian Academy of Sciences (India)
Toshimi Suda
2014-11-01
A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.
Cross-correlation laser scattering.
Kam, Z; Rigler, R
1982-01-01
Cross-correlation between two detectors was applied to analyze laser light-scattering fluctuations. Laser scattering from random concentration fluctuations is spatially coherent over small angular areas that are inversely proportional in size to the dimension of the scattering volume. By cross-correlating scattering intensity fluctuations in different angles, the correlation due to relaxation of concentration fluctuations is practically eliminated, and correlations reflecting changes in the s...
Slow Neutron Scattering by Benzene
International Nuclear Information System (INIS)
We have calculated the scattering of slow neutrons by the benzene molecule. The calculations are carried out within the framework of the time dependent formalism of Zemach and Glauber. Detailed account is taken of the effects of the molecular vibrations on the neutron scattering. Among the results explicitly calculated are the slow neutron total scattering cross-section as a function of energy and the energy angular distribution of singly scattered sections. (author)
Electron scattering on molecular hydrogen
International Nuclear Information System (INIS)
The author considers scattering phenomena which occur when a beam of electrons interacts with a molecular hydrogen gas of low density. Depending on the energy loss of the scattered electrons one can distinguish elastic scattering, excitation and (auto)ionization of the H2-molecule. The latter processes may also lead to dissociation. These processes are investigated in four experiments in increasing detail. (Auth.)
Low energy + scattering on = nuclei
Indian Academy of Sciences (India)
Swapan Das; Arun K Jain
2003-11-01
The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.
Boehlert, George W.
The cover of the March 1 issue of Eos showed a time series of acoustic scattering above Southeast Hancock Seamount (29°48‧N, 178°05‧E) on July 17-18, 1984. In a comment on that cover Martin Hovland (Eos, August 2, p. 760) argued that gas or “other far reaching causes” may be involved in the observed acoustic signals. He favors a hypothesis that acoustic scattering observed above a seeping pockmark in the North Sea is a combination of bubbles, stable microbubbles, and pelagic organisms and infers that this may be a more general phenomenon and indeed plays a role in the attraction of organisms to seamounts
Coherent Scatter Imaging Measurements
Ur Rehman, Mahboob
In conventional radiography, anatomical information of the patients can be obtained, distinguishing different tissue types, e.g. bone and soft tissue. However, it is difficult to obtain appreciable contrast between two different types of soft tissues. Instead, coherent x-ray scattering can be utilized to obtain images which can differentiate between normal and cancerous cells of breast. An x-ray system using a conventional source and simple slot apertures was tested. Materials with scatter signatures that mimic breast cancer were buried in layers of fat of increasing thickness and imaged. The result showed that the contrast and signal to noise ratio (SNR) remained high even with added fat layers and short scan times.
Protostring Scattering Amplitudes
Thorn, Charles B
2016-01-01
We calculate some tree level scattering amplitudes for a generalization of the protostring, which is a novel string model implied by the simplest string bit models. These bit models produce a lightcone worldsheet which supports $s$ integer moded Grassmann fields. In the generalization we supplement this Grassmann worldsheet system with $d=24-s$ transverse coordinate worldsheet fields. The protostring corresponds to $s=24$ and the bosonic string to $s=0$. The interaction vertex is a simple overlap with no operator insertions at the break/join point. Assuming that $s$ is even we calculate the multi-string scattering amplitudes by bosonizing the Grassmann fields, each pair equivalent to one compactified bosonic field, and applying Mandelstam's interacting string formalism to a system of $s/2$ compactified and $d$ uncompactified bosonic worldsheet fields. We obtain all amplitudes for open strings with no oscillator excitations and for closed strings with no oscillator excitations and zero winding number. We then ...
Positron scattering from tetrahydrofuran
Brunger, M. J.; Chiari, L.; Tattersall, W.; Anderson, E.; Machacek, J.; Makochekanwa, C.; Sullivan, J.; Buckman, S. J.
2012-10-01
We present recent experimental results for positron scattering from tetrahydrofuran. Being a model for the deoxyribose sugar rings in the nucleic acids backbone, tetrahydrofuran is of particular interest for investigating radiation damage in biomolecular systems. The measurements on this species were carried out using the atomic and molecular trap-based positron beamline at The Australian National University with an energy resolution of ˜60 meV. Total cross sections and integral cross sections for the positronium formation, elastic and inelastic (direct ionization and electronic excitation) scattering channels are presented over the energy range of 1-190 eV. Low-energy elastic differential cross sections are also presented at selected energies between 1 eV and 25 eV. A fairly good agreement is found with the total cross section results from the only existing previous experimental investigation on this target species by the Trento group.
Scattering with partial information
Carney, Daniel; Semenoff, Gordon
2016-01-01
We study relativistic scattering when one only has access to a subset of the particles, using the language of quantum measurement theory. We give an exact, non-perturbative formula for the von Neumann entanglement entropy of an apparatus particle scattered off an arbitrary set of system particles, in either the elastic or inelastic regime, and show how to evaluate it perturbatively. We give general formulas for the late-time expectation values of apparatus observables. Some simple example applications are included: in particular, a protocol to verify preparation of coherent superpositions of spatially localized system states using position-space information in the outgoing apparatus state, at lowest order in perturbation theory in a weak apparatus-system coupling.
Energy Technology Data Exchange (ETDEWEB)
Vernon, M.F.
1983-07-01
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.
Czech Academy of Sciences Publication Activity Database
Banakh, T.; Bonnet, R.; Kubiś, Wieslaw
2014-01-01
Roč. 2, č. 1 (2014), s. 5-10. ISSN 2299-3231 R&D Projects: GA ČR(CZ) GAP201/12/0290 Institutional support: RVO:67985840 Keywords : scattered compact space * mean operation Subject RIV: BA - General Mathematics http://www.degruyter.com/view/j/taa.2014.2.issue-1/taa-2014-0002/taa-2014-0002.xml
Scatter fraction with simulations
International Nuclear Information System (INIS)
In this work, the authors revisit the measurements of Trout and Kelley, and Simpkin and Dixon, by means of Monte Carlo simulations. Starting with a simple cylindrical homogeneous phantom, the authors introduce a more realistic phantom and the effect of the bucky in the simulations. The results indicate that optimised shielding methodologies should not neglect the attenuation and scattering by the patient plus bucky. (authors)
International Nuclear Information System (INIS)
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl → NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(22P/sub 3/2/) and Na(32P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included
Quantum scattering transformation
International Nuclear Information System (INIS)
There are three successful lines of development in one-dimensional mathematical physics: theory of quantum mechanics, theory of planar models in statistical mechanics, and inverse scattering method in classical field theory. It has been realized that the third method can be quantized to create a unified approach called Quantum Inverse Method, or quantum scattering transformation (QST). Recent developments are compiled in this text. Basic formula of QST are derived. Examples, for the nonlinear Schroedinger equation, and the Sine-Gordon equations, are given. A few problems are treated. The inverse problem of reconstructing the field variables from given scattering data is solved by the Gelfand-Levitan-Marchencko (GLM) equation. In summary, the QST model leads to the exact solution of field-theoretical models, and produces new models. It teaches that particles spectrum above the physical ground state can be considerably different from the predictions of perturbation theory. QST presents us with a ''prolific playground'' in quantum field theory and mathematical physics
Neutron scattering in Australia
International Nuclear Information System (INIS)
Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains
Neutron scattering in Australia
Energy Technology Data Exchange (ETDEWEB)
Knott, R.B. [Australian Nuclear Science and Technology Organisation, Menai (Australia)
1994-12-31
Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains.
International Nuclear Information System (INIS)
This series of lectures on basic scattering theory were given as part of a course for postgraduate high energy physicists and were designed to acquaint the student with some of the basic language and formalism used for the phenomenological description of nuclear reactions and decay processes used for the study of elementary particle interactions. Well established and model independent aspects of scattering theory, which are the basis of S-matrix theory, are considered. The subject is considered under the following headings; the S-matrix, cross sections and decay rates, phase space, relativistic kinematics, the Mandelstam variables, the flux factor, two-body phase space, Dalitz plots, other kinematic plots, two-particle reactions, unitarity, the partial-wave expansion, resonances (single-channel case), multi-channel resonances, analyticity and crossing, dispersion relations, the one-particle exchange model, the density matrix, mathematical properties of the density matrix, the density matrix in scattering processes, the density matrix in decay processes, and the helicity formalism. Some exercises for the students are included. (U.K.)
Scattering of intermediate energy protons
International Nuclear Information System (INIS)
The scattering of 1 GeV protons appears to be a powerful means of investigating nuclear matter. We worked with SPESI and the formalism of Kerman-Mc Manus and Thaler. The amplitude of nucleon-nucleon scattering was studied as were the aspects of 1 GeV proton scattering (multiple scattering, absorption, spin-orbit coupling, N-N amplitude, KMT-Glauber comparison, second order effects). The results of proton scattering on 16O, the isotopes of calcium, 58Ni, 90Zr and 208Pb are given
Scattering Solar Thermal Concentrators
Energy Technology Data Exchange (ETDEWEB)
Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)
2015-01-31
This program set out to explore a scattering-based approach to concentrate sunlight with the aim of improving collector field reliability and of eliminating wind loading and gross mechanical movement through the use of a stationary collection optic. The approach is based on scattering sunlight from the focal point of a fixed collection optic into the confined modes of a sliding planar waveguide, where it is transported to stationary tubular heat transfer elements located at the edges. Optical design for the first stage of solar concentration, which entails focusing sunlight within a plane over a wide range of incidence angles (>120 degree full field of view) at fixed tilt, led to the development of a new, folded-path collection optic that dramatically out-performs the current state-of-the-art in scattering concentration. Rigorous optical simulation and experimental testing of this collection optic have validated its performance. In the course of this work, we also identified an opportunity for concentrating photovoltaics involving the use of high efficiency microcells made in collaboration with partners at the University of Illinois. This opportunity exploited the same collection optic design as used for the scattering solar thermal concentrator and was therefore pursued in parallel. This system was experimentally demonstrated to achieve >200x optical concentration with >70% optical efficiency over a full day by tracking with <1 cm of lateral movement at fixed latitude tilt. The entire scattering concentrator waveguide optical system has been simulated, tested, and assembled at small scale to verify ray tracing models. These models were subsequently used to predict the full system optical performance at larger, deployment scale ranging up to >1 meter aperture width. Simulations at an aperture widths less than approximately 0.5 m with geometric gains ~100x predict an overall optical efficiency in the range 60-70% for angles up to 50 degrees from normal. However, the
Positron scattering by potassium
International Nuclear Information System (INIS)
Coupled-state calculations in a K(4s, 4p, 5s, 5p, 3d) + Ps(1s, 2s, 2p, 3s, 3p, 3d) approximation are reported for positron scattering by ground-state potassium in the energy range 0.5-60.0 eV. Comparison is made with the earlier work of Hewitt et al (1993, 1994) in a K(4s, 4p, 5s, 5p) + Ps(1s, 2s, 2p) approximation. For the first time cross sections for positronium formation in n = 3 states are obtained. (author)
Energy Technology Data Exchange (ETDEWEB)
Edwards, D.F.
1988-09-30
A tutorial presentation is given of Raman scattering in crystals. The physical concepts are emphasized rather than the detailed mathematical formalism. Starting with an introduction to the concepts of phonons and conservation laws, the effects of photon-phonon interactions are presented. This interaction concept is shown for a simple cubic crystal and is extended to a uniaxial crystal. The correlation table method is used for determining the number and symmetry of the Raman active modes. Finally, examples are given to illustrate the relative ease of using this group theoretical method and the predictions are compared with measured Raman spectra. 37 refs., 17 figs., 6 tabs.
Scattering configuration spaces
Melrose, Richard; Singer, Michael
2008-01-01
For a compact manifold with boundary $X$ we introduce the $n$-fold scattering stretched product $X^n_{\\text{sc}}$ which is a compact manifold with corners for each $n,$ coinciding with the previously known cases for $n=2,3.$ It is constructed by iterated blow up of boundary faces and boundary faces of multi-diagonals in $X^n.$ The resulting space is shown to map smoothly, by a b-fibration, covering the usual projection, to the lower stretched products. It is anticipated that this manifold wit...
International Nuclear Information System (INIS)
A tutorial presentation is given of Raman scattering in crystals. The physical concepts are emphasized rather than the detailed mathematical formalism. Starting with an introduction to the concepts of phonons and conservation laws, the effects of photon-phonon interactions are presented. This interaction concept is shown for a simple cubic crystal and is extended to a uniaxial crystal. The correlation table method is used for determining the number and symmetry of the Raman active modes. Finally, examples are given to illustrate the relative ease of using this group theoretical method and the predictions are compared with measured Raman spectra. 37 refs., 17 figs., 6 tabs
Multiple Parton Scattering in Nuclei: Quark-quark Scattering
Schafer, Andreas; Wang, Xin-Nian; Zhang, Ben-Wei
2007-01-01
Modifications to quark and antiquark fragmentation functions due to quark-quark (antiquark) double scattering in nuclear medium are studied systematically up to order \\cal{O}(\\alpha_{s}^2)$ in deeply inelastic scattering (DIS) off nuclear targets. At the order $\\cal{O}(\\alpha_s^2)$, twist-four contributions from quark-quark (antiquark) rescattering also exhibit the Landau-Pomeranchuck-Midgal (LPM) interference feature similar to gluon bremsstrahlung induced by multiple parton scattering. Comp...
Electromagnetic Scattering and Material Characterization
Omar, Abbas
2011-01-01
Based on the author's more-than 30 years of experience, this first-of-its-kind volume presents a comprehensive and systematic analysis of electromagnetic fields and their scattering by material objects. The book considers all three categories of scattering environments commonly used for material measurements – unbounded regions, waveguides, and cavity resonators. The book covers such essential topics as electromagnetic field propagation, radiation, and scattering, containing mathematically rigorous approaches for the computation of electromagnetic fields and the explanation of their behavior.
Heterodyne Near-Field Scattering
Brogioli, D; Giglio, M; Giglio, Marzio
2002-01-01
We describe an optical technique based on the statistical analysis of the random intensity distribution due to the interference of the near-field scattered light with the strong transmitted beam. It is shown that, from the study of the two-dimensional power spectrum of the intensity, one derives the scattered intensity as a function of the scattering wave vector. Near-field conditions are specified and discussed. The substantial advantages over traditional scattering technique are pointed out, and is indicated that the technique could be of interest for wave lengths other than visible light.
Light scattering by small particles
Hulst, H C van de
1981-01-01
""A must for researchers using the techniques of light scattering."" ? S. C. Snowdon, Journal of the Franklin InstituteThe measurement of light scattering of independent, homogeneous particles has many useful applications in physical chemistry, meteorology and astronomy. There is, however, a sizeable gap between the abstract formulae related to electromagnetic-wave-scattering phenomena, and the computation of reliable figures and curves. Dr. van de Hulst's book enables researchers to bridge that gap. The product of twelve years of work, it is an exhaustive study of light-scattering properties
International Nuclear Information System (INIS)
The theory of stimulated Thomson scattering is investigated both quantum mechanically and classically. Two monochromatic electromagnetic waves of like polarization travelling in opposite directions are allowed to interact for a time tau with the electrons in a collisionless plasma. The electromagnetic waves have frequencies well above the plasma frequency, and their difference frequency is allowed to range upward from the plasma frequency. With the difference frequency well above the plasma frequency, the rate at which energy is transferred from one wave to the other is calculated quantum mechanically, classically from a fluid theory, and classically from an independent electron theory. The rate is calculated in both the homogeneously broadened limit, and in the inhomogeneously broadened limit
Cardona, Carlos
2016-01-01
Recently the CHY approach has been extended to one loop level using elliptic functions and modular forms over a Jacobian variety. Due to the difficulty in manipulating these kind of functions, we propose an alternative prescription that is totally algebraic. This new proposal is based on an elliptic algebraic curve embedded in a $\\mathbb{C}P^2$ space. We show that for the simplest integrand, namely the ${\\rm n-gon}$, our proposal indeed reproduces the expected result. By using the recently formulated $\\Lambda-$algorithm, we found a novel recurrence relation expansion in terms of tree level off-shell amplitudes. Our results connect nicely with recent results on the one-loop formulation of the scattering equations. In addition, this new proposal can be easily stretched out to hyperelliptic curves in order to compute higher genus.
Surface enhanced Raman scattering
Furtak, Thomas
1982-01-01
In the course of the development of surface science, advances have been identified with the introduction of new diagnostic probes for analytical characterization of the adsorbates and microscopic structure of surfaces and interfaces. Among the most recently de veloped techniques, and one around which a storm of controversy has developed, is what has now been earmarked as surface enhanced Raman scattering (SERS). Within this phenomenon, molecules adsorbed onto metal surfaces under certain conditions exhibit an anomalously large interaction cross section for the Raman effect. This makes it possible to observe the detailed vibrational signature of the adsorbate in the ambient phase with an energy resolution much higher than that which is presently available in electron energy loss spectroscopy and when the surface is in contact with a much larger amount of material than that which can be tolerated in infrared absorption experiments. The ability to perform vibrational spectroscopy under these conditions would l...
Energy Technology Data Exchange (ETDEWEB)
Kegel, Gunter H.R.; Egan, James J
2007-04-18
This project covers four principal areas of research: Elastic and inelastic neutron scattering studies in odd-A terbium, thulium and other highly deformed nuclei near A=160 with special regard to interband transitions and to the investigation of the direct-interaction versus the compound-nucleus excitation process in these nuclei. Examination of new, fast photomultiplier tubes suitable for use in a miniaturized neutron-time-of-flight spectrometer. Measurement of certain inelastic cross sections of 238U. Determination of the multiplicity of prompt fission gamma rays in even-A fissile actinides. Energies and mean lives of fission isomers produced by fast fission of even-Z, even-A actinides. Study of the mean life of 7Be in different host matrices and its possible astro-physical significance.
Scattering corrections in neutron radiography using point scattered functions
Kardjilov, N.; de Beer, F.; Hassanein, R.; Lehmann, E.; Vontobel, P.
2005-04-01
Scattered neutrons cause distortions and blurring in neutron radiography pictures taken at small distances between the investigated object and the detector. This defines one of the most significant problems in quantitative neutron radiography. The quantification of strong scattering materials such as hydrogenous materials—water, oil, plastic, etc.—with a high precision is very difficult due to the scattering effect in the radiography images. The scattering contribution in liquid test samples (H 2O, D 2O and a special type oil ISOPAR L) at different distances between the samples and the detector, the so-called Point Scattered Function (PScF), was calculated with the help of MCNP-4C Monte Carlo code. Corrections of real experimental data were performed using the calculated PScF. Some of the results as well as the correction algorithm will be presented.
Quantum scattering in one dimension
Energy Technology Data Exchange (ETDEWEB)
Barlette, Vania E. [Centro Universitario Franciscano, Santa Maria, RS (Brazil); Leite, Marcelo M. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil); Adhikari, Sadhan K. [Instituto de Fisica Teorica, Universidade Estadual Paulista, Sao Paulo, SP (Brazil)
2000-09-01
A self-contained discussion of non-relativistic quantum scattering is presented in the case of central potentials in one space dimension, which will facilitate the understanding of the more complex scattering theory in two and three dimensions. The present discussion illustrates in a simple way the concepts of partial-wave decomposition, phase shift, optical theorem and effective-range expansion. (author)
Quantum scattering at low energies
DEFF Research Database (Denmark)
Derezinski, Jan; Skibsted, Erik
For a class of negative slowly decaying potentials, including with , we study the quantum mechanical scattering theory in the low-energy regime. Using modifiers of the Isozaki--Kitada type we show that scattering theory is well behaved on the {\\it whole} continuous spectrum of the Hamiltonian...
Quantum scattering at low energies
DEFF Research Database (Denmark)
Derezinski, Jan; Skibsted, Erik
2009-01-01
For a class of negative slowly decaying potentials, including V(x):=−γ|x|−μ with 0<μ<2 , we study the quantum mechanical scattering theory in the low-energy regime. Using appropriate modifiers of the Isozaki–Kitada type we show that scattering theory is well behaved on the whole continuous spectrum...
Neutron scattering in magnetic fields
International Nuclear Information System (INIS)
The use of magnetic fields in neutron scattering experimentation is reviewed briefly. Two general areas of application can be distinguished. In one the field acts to change the properties of the scattering sample; in the second the field acts on the neutron itself. Several examples are discussed. Precautions necessary for high precision polarized beam measurements are reviewed. 33 references
Dynamic measurement of forward scattering
DEFF Research Database (Denmark)
Appel-Hansen, Jørgen; Rusch, W.
1975-01-01
A dynamic method for the measurement of forward scattering in a radio anechoic chamber is described. The quantity determined is the induced-field-ratio (IFR) of conducting cylinders. The determination of the IFR is highly sensitive to 1) multiple scattering between the cylinder and the obpring...
Neutron scattering in magnetic fields
Koehler, W.C.
1984-01-01
The use of magnetic fields in neutron scattering experimentation is reviewed briefly. Two general areas of application can be distinguished. In one the field acts to change the properties of the scattering sample ; in the second the field acts on the neutron itself. Several examples are discussed. Precautions necessary for high precision polarized beam measurements are reviewed.
Compton scattering on hadronic systems
International Nuclear Information System (INIS)
Compton scattering with real photons is studied for several hadronic systems, where special care is taken of the internal structure of the systems. The scattering on the deuteron is treated in terms of an analytically solvable model in the low energy region as in illustration for the general theory of low energy Compton scattering. For the 208Pb target nucleus a consistent treatment of the retardation leads to an interpretation of scattering data below and above the giant resonances up to energies of 50 MeV. Compton scattering in the Δ-resonance region is studied for the nucleon. The internal structure is described via a constituent quark model resulting in a proper treatment of the polarizabilities of the nucleon. The effect of binding on the polarizabilities is discussed on the basis of kinematical effects and modifictions due to the retardation. (orig.)
Delbrueck scattering of monoenergetic photons
International Nuclear Information System (INIS)
The Delbrueck effect was experimentally investigated in high Z nuclei with monoenergetic photons in the range 6.8-11.4 MeV. Two different methods were used for measurements of the differential scattering cross-section, in the 25-140 deg range and in the forward direction (theta = 1.5 deg), respectively. The known Compton scattering cross-section was used in a new and unique way for the determination of the elastic scattering cross-section. Isolation of the contribution of the real Delbrueck amplitudes to the cross-section was crried out successfully. Experimental confirmation of the theoretical calculations of Papatzacos and Mork and measurement, for the first time, of the Rayleigh scattering in the 10 MeV region are also reported. One of the most interesting findings is the presence of Coulomb corrections in Delbrueck scattering at these energies. More theoretical effort is needed in this last direction. (author)
Calculation of Thermal Scattering Kernels
International Nuclear Information System (INIS)
A long-standing programme at General Atomic has been the development of physical models to describe the scattering of slow neutrons from the various moderators and the numerical methods necessary for the computation of thermal neutron cross-sections and scattering kernels. This paper contains a review of the recent developments and improvements in the scattering descriptions and subsequent kernels for the moderators Be, C, H2O, D2O, CH2, H2 and D2. In particular for the moderators Be and C accurate phonon spectra, obtained by the root sampling technique, are presented along with comparisons to demonstrate how well the scattering models can predict the results of cross-section and spectral measurements. While the treatment of H2O is essentially that of Nelkin, curves of calculated and experimental neutron spectra are shown, which demonstrate that the inclusion of anisotropic effects for the molecular vibrations improve the agreement between theory and experiment. Following Butler's description of neutron scattering by D2O, a scattering kernel has been obtained which predicts quite accurately integral quantities such as neutron spectra and angular as well as total scattering cross-sections. An interesting result of the curves shown is that the inter- and intramolecular interference effects tend to cancel so that an incoherent approximation is quite adequate to calculate neutron spectra in D2O for the case of infinite media or weakly space-dependent problems. By utilizing the treatment by Lin and Koenig of the vibrational modes of infinite CH2 chains, a scattering kernel has been obtained which results in very good agreement between the predicted and experimental total cross-section and neutron spectra. Curves are presented to demonstrate this agreement between theory and experiment. Neutron spectra have been calculated for liquid hydrogen at boiling using a very accurate scattering description. These spectra are shown in the paper to be very sensitive both to
Rahman, M A; Haque, S
2003-01-01
Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. sup 9 Be, sup 1 sup 6 O, sup 2 sup 0 Ne and sup 3 sup 2 S heavy-ion beams elastic scattering from sup 2 sup 8 Si, sup 2 sup 4 Mg and sup 4 sup 0 Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-paramet...
International Nuclear Information System (INIS)
Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. 9Be,16O, 20Ne and 32S heavy-ion beams elastic scattering from 28Si, 24Mg and 40Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-parameter formalism of the present quantal formulation and from the Strong Absorption Model for comparison. Typical fits are shown and the nuclear parameters obtained from the analyses of both approaches are presented. (author)
Atomistic scattering close to an interface
International Nuclear Information System (INIS)
Half-space Green functions and T-matrix theory is used to predict that scattering on discrete dopants close to a perfect interface generates strong deviations from scattering in the bulk. Interference between the scattered wave and its reflection from the interface leads to a dipolar scattering rate. By introducing de-coherence the transition to bulk scattering is described quantitatively for strongly screened Coulomb scattering
Atomistic scattering close to an interface
Energy Technology Data Exchange (ETDEWEB)
Barker, J R; Watling, J R [Nanoelectronics Research Centre, Department of Electronics and Electrical Engineering, University of Glasgow, G12 8LT, Scotland (United Kingdom)
2006-05-15
Half-space Green functions and T-matrix theory is used to predict that scattering on discrete dopants close to a perfect interface generates strong deviations from scattering in the bulk. Interference between the scattered wave and its reflection from the interface leads to a dipolar scattering rate. By introducing de-coherence the transition to bulk scattering is described quantitatively for strongly screened Coulomb scattering.
Radar interferometry persistent scatterer technique
Kampes, Bert M
2006-01-01
Only book on Permanent Scatterer technique of radar interferometryExplains the Permanent Scatterer technique in detail, possible pitfalls, and details a newly developed stochastic model and estimator algorithm to cope with possible problems for the application of the PS techniqueThe use of Permanent Scatterer allows very precise measurements of the displacement of hundreds of points per square kilometerDescribes the only technique currently able to perform displacement measurements in the past, utilizing the ERS satellite data archive using data acquired from 1992-prese
Quantitative scattering of melanin solutions
Riesz, J; Meredith, P; Gilmore, Joel; Meredith, Paul; Riesz, Jennifer
2005-01-01
The optical scattering coefficient of a dilute, well solubilised eumelanin solution has been accurately measured as a function of incident wavelength, and found to contribute less than 6% of the total optical attenuation between 210 and 325nm. At longer wavelengths (325nm to 800nm) the scattering was less than the minimum sensitivity of our instrument. This indicates that UV and visible optical density spectra can be interpreted as true absorption with a high degree of confidence. The scattering coefficient vs wavelength was found to be consistent with Rayleigh Theory for a particle radius of 38+-1nm.
Neutron scattering and hydrogen storage
Directory of Open Access Journals (Sweden)
A.J. Ramirez-Cuesta
2009-11-01
Full Text Available Hydrogen has been identified as a fuel of choice for providing clean energy for transport and other applications across the world and the development of materials to store hydrogen efficiently and safely is crucial to this endeavour. Hydrogen has the largest scattering interaction with neutrons of all the elements in the periodic table making neutron scattering ideal for studying hydrogen storage materials. Simultaneous characterisation of the structure and dynamics of these materials during hydrogen uptake is straightforward using neutron scattering techniques. These studies will help us to understand the fundamental properties of hydrogen storage in realistic conditions and hence design new hydrogen storage materials.
Optical scattering on ferrofluid agglomerates
Bacri, J. -C.; Salin, D.
1982-01-01
Direct microscopic observation of a thin sample of ionic ferrofluid, in the presence of a magnetic field, shows the existence of a locally hexagonal lattice of agglomerates. We have observed the unusual pattern of the light scattered by this array.
Scattering by a nihility cylinder
Lakhtakia, A
2006-01-01
The total scattering and the extinction efficiencies of a nihility cylinder of infinite length and circular cross--section are identical and independent of the polarization state of a normally incident plane wave.
Unveiling small sphere's scattering behavior
Tzarouchis, Dimitrios C; Sihvola, Ari
2016-01-01
A classical way for exploring the scattering behavior of a small sphere is to approximate Mie coefficients with a Taylor series expansion. This ansatz delivered a plethora of insightful results, mostly for small spheres supporting electric localized plasmonic resonances. However, many scattering aspects are still uncharted, especially for the case of magnetic resonances. Here, an alternative system ansatz is proposed based on the Pad\\'e approximants for the Mie coefficients. The extracted results reveal new aspects, such as the existence of a self-regulating radiative damping mechanism for the first magnetic resonance. Hence, a systematic way of exploring the scattering behavior is introduced, sharpening our understanding about sphere's scattering behavior and its emergent functionalities.
Neutron scattering and models: Titanium
Energy Technology Data Exchange (ETDEWEB)
Smith, A.B.
1997-07-01
Differential neutron elastic-scattering cross sections of elemental titanium were measured from 4.5 {r_arrow} 10.0 MeV in incident energy increments of {approx} 0.5 MeV. At each energy the measurements were made at forty or more scattering angles distributed between {approx} 17 and 160{degree}. Concurrently, differential neutron inelastic-scattering cross sections were measured for observed excitations of 0.975 {+-} 0.034, 1.497 {+-} 0.033, 2.322 {+-} 0.058, 3.252 {+-} 0.043, 3.700 {+-} 0.093, 4.317 {+-} 0.075 and 4.795 {+-} 0.100 MeV. All of the observed inelastically-scattered neutron groups were composites of contributions from several isotopes and/or levels. The experimental results were used to develop energy-average optical, statistical and coupled-channels models.
Quantum computation with scattering matrices
Giorgadze, G.; Tevzadze, R.
2006-01-01
We discuss possible applications of the 1-D direct and inverse scattering problem to design of universal quantum gates for quantum computation. The potentials generating some universal gates are described.
Analytization of elastic scattering amplitude
Troshin, S M
2016-01-01
Dependence of the real part of the elastic scattering amplitude on the transferred momentum -t at the asymptotical energies has been restored from the corresponding imaginary part on the basis of derivative analyticity relations (analytization).
Resonantly scattering crystals and surfaces
International Nuclear Information System (INIS)
We examine coherence effects from forming a crystal of resonant scatterers by generalising the Fano model for autoionising resonances in electron scattering from atoms to a lattice of such scatterers. (We have in mind the case of neutron scattering from nuclei.) We solve this problem to yield two branches to the dispersion relation for the neutron in general and three when the resonance coincides with a Brillouin Zone boundary. The 'width' of the resonance is enhanced over the isolated nucleus, the best candidate for observation being the 2eV 185Re resonance near the Bragg condition. We use these results to calculate the reflection coefficient from a surface, revealing total external reflection near resonance. We discuss experimental feasibility in both the neutron and electron cases. (author)
Nanocatalytic resonance scattering spectral analysis
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The resonance scattering spectral technique has been established using the synchronous scanning technique on spectrofluorometry.Because of its advantages of simplicity,rapidity and sensitivity,it has been widely applied to analyses of proteins,nucleic acids and inorganic ions.This paper summarizes the application of immunonanogold and aptamer modified nanogold(AptAu) catalytic resonance scattering spectral technique in combination with the work of our group,citing 53 references.
Scattering Equations and KLT Orthogonality
Cachazo, Freddy; He, Song; Yuan, Ellis Ye
2013-01-01
Several recent developments point to the fact that rational maps from n-punctured spheres to the null cone of D dimensional momentum space provide a natural language for describing the scattering of massless particles in D dimensions. In this note we identify and study equations relating the kinematic invariants and the puncture locations, which we call the scattering equations. We provide an inductive algorithm in the number of particles for their solutions and prove a remarkable property wh...
Virtual photon-photon scattering
Hoferichter, Martin; Colangelo, Gilberto; Procura, Massimiliano; Stoffer, Peter(Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, Bern, CH-3012, Switzerland)
2014-01-01
Based on analyticity, unitarity, and Lorentz invariance the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon is directly related to the cross section of e+e− → hadrons. We review the main difficulties that impede such an approach for light-by-light scattering and identify the required ingredients from experiment. Amongst those, the most critical one is the scattering of two virtual photons into meson pairs. We analyze the analytic structure of the pr...
Virtual photon-photon scattering
Hoferichter, Martin; Colangelo, Gilberto; Procura, Massimiliano; Stoffer, Peter(Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, Bern, CH-3012, Switzerland)
2013-01-01
Based on analyticity, unitarity, and Lorentz invariance the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon is directly related to the cross section of e^+e^- --> hadrons. We review the main difficulties that impede such an approach for light-by-light scattering and identify the required ingredients from experiment. Amongst those, the most critical one is the scattering of two virtual photons into meson pairs. We analyze the analytic structure of th...
Polarized lepton-nucleon scattering
International Nuclear Information System (INIS)
Deep inelastic polarized lepton-nucleon scattering is reviewed in three lectures. The first lecture covers the polarized deep inelastic scattering formalism and foundational theoretical work. The second lecture describes the nucleon spin structure function experiments that have been performed up through 1993. The third lecture discusses implication of the results and future experiments aimed at high-precision measurements of the nucleon spin structure functions
Cosmic Neutrino Last Scattering Surface
Dodelson, Scott
2009-01-01
Neutrinos decoupled from the rest of the cosmic plasma when the Universe was less than one second old, far earlier than the photons which decoupled at t=380,000 years. Surprisingly, though, the last scattering surface of the neutrinos is much closer to us than that of the photons. Here we calculate the properties of the last scattering surfaces of the three species of neutrinos.
Light scattering by cosmic particles
Hovenier, J.W.; Min, M.
2008-01-01
We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments. At light scattering conferences most attention is usually paid to Solar System bodies. The main purpose of this contribution is to provide a brief introduction to light scattering by cosmic particl...
Polarized lepton-nucleon scattering
Energy Technology Data Exchange (ETDEWEB)
Hughes, E.
1994-02-01
Deep inelastic polarized lepton-nucleon scattering is reviewed in three lectures. The first lecture covers the polarized deep inelastic scattering formalism and foundational theoretical work. The second lecture describes the nucleon spin structure function experiments that have been performed up through 1993. The third lecture discusses implication of the results and future experiments aimed at high-precision measurements of the nucleon spin structure functions.
Proton-tetraneutron elastic scattering
Sherrill, B. M.; Bertulani, C. A.
2003-01-01
We analyze the elastic scattering of protons on a 4n system. This was used as part of the detection technique of a recent experiment [1] to search for the 4n (tetraneutron) as a bound particle. We show that it is unlikely that this process alone could yield the events reported in ref. [1], unless the 4n has an anomalously large backward elastic scattering amplitude.
Multiple magnetic scattering in small-angle neutron scattering of Nd–Fe–B nanocrystalline magnet
Tetsuro Ueno; Kotaro Saito; Masao Yano; Masaaki Ito; Tetsuya Shoji; Noritsugu Sakuma; Akira Kato; Akira Manabe; Ai Hashimoto; Gilbert, Elliot P.; Uwe Keiderling; Kanta Ono
2016-01-01
We have investigated the influence of multiple scattering on the magnetic small-angle neutron scattering (SANS) from a Nd–Fe–B nanocrystalline magnet. We performed sample-thickness- and neutron-wavelength-dependent SANS measurements, and observed the scattering vector dependence of the multiple magnetic scattering. It is revealed that significant multiple scattering exists in the magnetic scattering rather than the nuclear scattering of Nd–Fe–B nanocrystalline magnet. It is considered that th...
Eikonal Scattering at Strong Coupling
Irizarry-Gelpi, Melvin Eloy
The scattering of subatomic particles is a source of important physical phenomena. Decades of work have yielded many techniques for the computation of scattering amplitudes. Most of these techniques involve perturbative quantum field theory and thus apply only at weak coupling. Complementary to scattering is the formation of bound states, which are intrinsically nonperturbative. Regge theory arose in the late 1950s as an attempt to describe, with a single framework, both scattering and the formation of bound states. In Regge theory one obtains an amplitude with bound state poles after analytic continuation of a nonperturbative scattering amplitude, corresponding to a sum of an infinite number of Feynman diagrams at large energy and fixed momentum transfer (but with crossed kinematics). Thus, in order to obtain bound states at fixed energy, one computes an amplitude at large momentum transfer. In this dissertation we calculate amplitudes with bound states in the regime of fixed energy and small momentum transfer. We formulate the elastic scattering problem in terms of many-body path integrals, familiar from quantum mechanics. Then we invoke the semiclassical JWKB approximation, where the path integral is dominated by classical paths. The dynamics in the semiclassical regime are strongly coupled, as found by Halpern and Siegel. When the momentum transfer is small, the classical paths are simple straight lines and the resulting semiclassical amplitudes display a spectrum of bound states that agrees with the spectrum found by solving wave equations with potentials. In this work we study the bound states of matter particles with various types of interactions, including electromagnetic and gravitational interactions. Our work has many analogies with the work started by Alday and Maldacena, who computed scattering amplitudes of gluons at strong coupling with semiclassical quantum mechanics of strings in anti de-Sitter spacetime. We hope that in the future we can apply our
Fundamentals of neutron scattering by condensed matter
Energy Technology Data Exchange (ETDEWEB)
Scherm, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-12-31
The purpose of this introductory lecture is to give the basic facts about the scattering of neutrons by condensed matter. This lecture is restricted to nuclear scattering, whereas magnetic scattering will be dealt with in an other course. Most of the formalism, however, can also be easily extended to magnetic scattering. (author) 17 figs., 3 tabs., 10 refs.
Fundamentals of neutron scattering by condensed matter
International Nuclear Information System (INIS)
The purpose of this introductory lecture is to give the basic facts about the scattering of neutrons by condensed matter. This lecture is restricted to nuclear scattering, whereas magnetic scattering will be dealt with in an other course. Most of the formalism, however, can also be easily extended to magnetic scattering. (author) 17 figs., 3 tabs., 10 refs
High frequency and pulse scattering physical acoustics
Pierce, Allan D
1992-01-01
High Frequency and Pulse Scattering investigates high frequency and pulse scattering, with emphasis on the phenomenon of echoes from objects. Geometrical and catastrophe optics methods in scattering are discussed, along with the scattering of sound pulses and the ringing of target resonances. Caustics and associated diffraction catastrophes are also examined.Comprised of two chapters, this volume begins with a detailed account of geometrically based approximation methods in scattering theory, focusing on waves transmitted through fluid and elastic scatterers and glory scattering; surface ray r
Resonant elastic scattering, inelastic scattering and astrophysical reactions
International Nuclear Information System (INIS)
Nuclear reactions can occur at low kinetic energy. Low-energy reactions are characterized by a strong dependence on the structure of the compound nucleus. It turns out that it is possible to study the nuclear structure by measuring these reactions. In this course, three types of reactions are treated: Resonant Elastic Scattering (such as N14(p,p)N14), Inelastic Scattering (such as N14(p,p')N14*) and Astrophysical reactions (such as N14(p,γ)O15). (author)
Neutron detector resolution for scattering
Energy Technology Data Exchange (ETDEWEB)
Kolda, S.A. [Rensselaer Polytechnic Inst., Troy, NY (United States)
1997-03-01
A resolution function has been determined for scattered neutron experiments at Rensselaer Polytechnic Institute (RPI). This function accounts for the shifting and broadening of the resonance peak due to the additional path length, traveled by the neutron after scattering and prior to detection, along with the broadening of the resonance peak due to the bounce target. This resolution function has been parameterized both in neutron energy and size of the sample disk. Monte Carlo Neutron and Photon (MCNP) modeling has been used to determine the shape of the detector resolution function while assuming that the sample nucleus has an infinite mass. The shape of the function for a monoenergetic neutron point source has been compared to the analytical solution. Additionally, the parameterized detector resolution function has been used to broaden the scatter yield calculated from Evaluated Neutron Data File ENDF/B-VI cross section data for {sup 238}U. The target resolution function has been empirically determined by comparison of the broadened scatter yield and the experimental yield for {sup 238}U. The combined resolution function can be inserted into the SAMMY code to allow resonance analysis for scattering measurements.
Electromagnetic wave scattering by Schwarzschild black holes.
Crispino, Luís C B; Dolan, Sam R; Oliveira, Ednilton S
2009-06-12
We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor, and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time. PMID:19658920
Scattering Equations and KLT Orthogonality
Cachazo, Freddy; Yuan, Ellis Ye
2013-01-01
Several recent developments point to the fact that rational maps from n-punctured spheres to the null cone of D dimensional momentum space provide a natural language for describing the scattering of massless particles in D dimensions. In this note we identify and study equations relating the kinematic invariants and the puncture locations, which we call the scattering equations. We provide an inductive algorithm in the number of particles for their solutions and prove a remarkable property which we call KLT Orthogonality. In a nutshell, KLT orthogonality means that "Parke-Taylor" vectors constructed from the solutions to the scattering equations are mutually orthogonal with respect to the Kawai-Lewellen-Tye (KLT) bilinear form. We end with comments on possible connections to gauge theory and gravity amplitudes in any dimension and to the high-energy limit of string theory amplitudes.
Nuclear Scattering from Transition Metals
Hira, Ajit; McKeough, James; Valerio, Mario; Cathey, Tommy
2016-03-01
In view of the continued interest in the scattering of light projectiles by metallic nuclei, we present a computational study of the interactions between different nuclear species of atoms such as H through F (Z neutron scattering can be used to record holographic images of materials. We have developed a FORTRAN computer program to compute stopping cross sections and scattering angles in Ag and other metals for the small nuclear projectiles, using Monte Carlo calculation. This code allows for different angles of incidence. Next, simulations were done in the energy interval from 50 to 210 keV. The computational results thus obtained are compared with relevant experimental data. The data are further analyzed to identify periodic trends in terms of the atomic number of the projectile. Such studies also have potential applications in nuclear physics and in nuclear medicine. Funding from National Science Foundation.
Magnetic scattering and polarized neutrons
International Nuclear Information System (INIS)
The last few years have witnessed considerable progress in the use of polarized neutron beam techniques for the study of condensed matter physics. Among the methods actively pursued at present are neutron spin echo as pioneered by Mezei for ultra high resolution and the energy integrated magnetic scattering measurement technique developed by Brown and Ziebeck. We have concentrated on a medium resolution range utilizing 5 to 100 MeV polarized neutrons. In this review we discuss recent work at Brookhaven on the development of the triple axis neutron scattering technique with polarization analysis. We have now reached the stage where quantitative characterization, in absolute units, can be done for a wide range of energy and momentum transfers in paramagnetic scattering. We will discuss some examples of recent inelastic measurements on 3d ferromagnets as well as diffraction studies of multibilayer thin film structures
Parity violation and electron scattering
International Nuclear Information System (INIS)
I have been asked to set stage for the more specialized talks to follow and to review the history of parity nonconservation in electron scattering. In electron scattering, parity violation (PV) is the unique signal which allows us to study the weak interactions among the much stronger electromagnetic ones. It is observed through the detection of a pseudoscalar quantity in the cross section or rate of a reaction. These pseudoscalars usually involve a spin or polarization. Since it is known that spin effects are more sensitive to dynamics than differential or total cross sections, which are partially determined by geometry, PV measurements allow us to learn about the weak interactions and nucleon and nuclear structure. Because the weak interactions are of short range, the measurements are sensitive to different aspects of the target structure than the long range electromagnetic scattering. 15 refs., 7 figs
New Techniques in Neutron Scattering
DEFF Research Database (Denmark)
Birk, Jonas Okkels
Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher...... potential performance than any existing facility, however in order to use this pulse structure optimally many existing neutron scattering instruments will need to be redesigned. This defense will concentrate on the design and optimization of the inverse time-of-flight cold neutron spectrometer CAMEA. The...... unprecedented large fraction of neutrons scattered in the horizontal plane. Together with the ESS source this will produce an instrument that promises several orders of magnitude higher performance than the best currently existing neutron spectrometers. The design of CAMEA involved kinematic calculations...
SCATTERING FROM RAMIFIED POLYMERIC SYSTEMS
Directory of Open Access Journals (Sweden)
M.Benhamou
2004-01-01
Full Text Available Here, of great interest to us is a quantitative study of the scattering properties from ramified polymeric systems of arbitrary topology. We consider three types of systems, namely ramified polymers in solution, ramified polymer blends, or ternary mixtures made of two ramified polymers of different chemical nature immersed in a good solvent. To achieve the goal of the study, use is made of the Random Phase Approximation. First we determine the exact expression of the form factor of an ideal ramified polymer of any topology, from which we extract the exact expression of its gyration radius. Using the classical Zimm's formulae and the exact form factor, we determine all scattering properties of these three types of ramified polymeric systems. The main conclusion is that ramification of the chains induces drastic changes of the scattering properties.
Compton Scattering on Light Nuclei
Directory of Open Access Journals (Sweden)
Shukla D.
2010-04-01
Full Text Available Compton scattering on light nuclei (A = 2, 3 has emerged as an eﬀective avenue to search for signatures of neutron polarizabilities, both spin–independent and spin–dependent ones. In this discussion I will focus on the theoretical aspect of Compton scattering on light nuclei; giving ﬁrst a brief overview and therafter concentrating on our Compton scattering calculations based on Chiral eﬀective theory at energies of the order of pion mass. These elastic γd and γHe-3 calculations include nucleons, pions as the basic degrees of freedom. I will also discuss γd results where the ∆-isobar has been included explicitly. Our results on unpolarized and polarization observables suggest that a combination of experiments and further theoretical eﬀorts will provide an extraction of the neutron polarizabilities.
Helium atom scattering from surfaces
1992-01-01
High resolution helium atom scattering can be applied to study a number of interesting properties of solid surfaces with great sensitivity and accuracy. This book treats in detail experimental and theoretical aspects ofthis method as well as all current applications in surface science. The individual chapters - all written by experts in the field - are devoted to the investigation of surface structure, defect shapes and concentrations, the interaction potential, collective and localized surface vibrations at low energies, phase transitions and surface diffusion. Over the past decade helium atom scattering has gained widespread recognitionwithin the surface science community. Points in its favour are comprehensiveunderstanding of the scattering theory and the availability of well-tested approximation to the rigorous theory. This book will be invaluable to surface scientists wishing to make an informed judgement on the actual and potential capabilities of this technique and its results.
Commercial applications of neutron scattering
International Nuclear Information System (INIS)
The fact that industry is now willing to pay the full commercial cost for certain neutron scattering experiments aimed at solving its urgent materials - related problems is a true testimony to the usefulness of neutrons as microscopic probes. This paper gives examples of such use of three techniques drawn mainly from our experience at AEA Technology Harwell Laboratory. These are diffraction to measure residual stress, small angle neutron scattering to examine hardening precipitates in ferritic steels brought about by irradiation, and reflectivity to study amorphous diamond layers deposited on silicon. In most cases it is the penetrative power of the neutron which proves to be its best asset for commercial industrial applicaitons. (author)
[Inelastic electron scattering from surfaces
International Nuclear Information System (INIS)
This program uses ab-initio and multiple scattering to study surface dynamical processes; high-resolution electron-energy loss spectroscopy is used in particular. Off-specular excitation cross sections are much larger if electron energies are in the LEED range (50--300 eV). The analyses have been extended to surfaces of ordered alloys. Phonon eigenvectors and eigenfrequencies were used as inputs to electron-energy-loss multiple scattering cross section calculations. Work on low-energy electron and positron holography is mentioned
Summary of neutron scattering lengths
International Nuclear Information System (INIS)
All available neutron-nuclei scattering lengths are collected together with their error bars in a uniform way. Bound scattering lengths are given for the elements, the isotopes, and the various spin-states. They are discussed in the sense of their use as basic parameters for many investigations in the field of nuclear and solid state physics. The data bank is available on magnetic tape, too. Recommended values and a map of these data serve for an uncomplicated use of these quantities. (orig.)
Optical scattering measurement and analysis
Stover, John C
2012-01-01
Newly included are scatter models for pits and particles as well as the use of wafer scanners to locate and size isolated surface features. New sections cover the multimillion-dollar wafer scanner business, establishing that microroughness is the noise, not the signal, in these systems. Scatter measurements, now routinely used to determine whether small-surface features are pits or particles and inspiring new technology that provides information on particle material, are also discussed. These new capabilities are now supported by a series of international standards, and a new chapter reviews t
Invisibility cloaking in weak scattering
Setälä, Tero; Hakkarainen, Timo; Ari T. Friberg; Hoenders, Bernhard J.
2010-01-01
We consider invisibility cloaking of a slab object in scalar wave theory within the first-order Born approximation. We show that in the forward direction cloaking is achieved for any object slab and incident field, whereas in the backward direction cloaking is possible at least for self-imaging fields. In both cases the scattering potential of the cloak slab depends on that of the object slab. The method of object-dependent cloaking using weak slab scatterers can be a useful addition to exist...
Electron scattering off palladium isotopes
International Nuclear Information System (INIS)
The low-lying states of the even Pd isotopes are characterized by vibrator-like properties. In this thesis the results of an electron scattering experiment on the Pd isotopes, designed to study the description of such nuclei in the Anharmonic Vibrator Model (AVM) and the Interacting Boson Approximation (IBA), are presented and discussed. Data have been taken at the high-resolution electron scattering facility of NIKHEF-K and covered a momentum-transfer range of 0.4 to 2.5 fm-1. (Auth.)
Entanglement Entropy of Scattering Particles
Peschanski, Robi
2016-01-01
We study the entanglement entropy between the two outgoing particles in an elastic scattering process. It is formulated within an S-matrix formalism using the partial wave expansion of two-body states, which plays a significant role in our computation. As a result, we obtain a novel formula that describes the entanglement entropy in a high energy scattering by the use of physical observables, namely the elastic and total cross sections and a physical bound on the impact parameter range, related to the elastic differential cross-section.
High energy elastic hadron scattering
International Nuclear Information System (INIS)
The paper deals with the WA7 experiment at the CERN super proton synchrotron (SPS). The elastic differential cross sections of pion-proton, kaon-proton, antiproton-proton, and proton-proton at lower SPS energies over a wide range of momentum transfer were measured. Some theoretical models in the light of the experimental results are reviewed, and a comprehensive impact parameter analysis of antiproton-proton elastic scattering over a wide energy range is presented. A nucleon valence core model for high energy proton-proton and antiproton-proton elastic scattering is described
Entanglement entropy of scattering particles
Peschanski, Robi; Seki, Shigenori
2016-07-01
We study the entanglement entropy between the two outgoing particles in an elastic scattering process. It is formulated within an S-matrix formalism using the partial wave expansion of two-body states, which plays a significant role in our computation. As a result, we obtain a novel formula that expresses the entanglement entropy in a high energy scattering by the use of physical observables, namely the elastic and total cross sections and a physical bound on the impact parameter range, related to the elastic differential cross-section.
Remark on pion scattering lengths
Black, Deirdre; Jora, Renata; Park, Nae Woong; Schechter, Joseph; Shahid, M Naeem
2009-01-01
It is noted that the pattern of chiral perturbation theory predictions for both the isotopic spin 0 and isotopic spin 2 s-wave pion-pion scattering lengths to orders $p^2$, $p^4$ and $p^6$ seems to agree with the corresponding pattern of the tree level predictions of the SU(2) linear sigma model.
Scattering of solitons on resonance
Kiselev, O M; Glebov, S. G.
2004-01-01
We investigate a propagation of solitons for nonlinear Schrodinger equation under small driving force. The driving force passes the resonance. The process of scattering on the resonance leads to changing of number of solitons. After the resonance the number of solitons depends on the amplitude of the driving force.
Advances in neutron scattering research
International Nuclear Information System (INIS)
This issue of the Supplement to Journal of the Physical Society of Japan collects invited and contributed papers from the first International Symposium on Advanced Science Research (ASR-2000) 'Advances in Neutron Scattering Research'. The 182 of the presented papers are indexed individually. (J.P.N.)
Electron scattering from nuclear matter
International Nuclear Information System (INIS)
We use inclusive electron scattering to study the short-range aspects of nuclear matter wave functions. Comparison to data at large momentum transfer allows detailed studies of P(k, E) at large momenta, N-N correlations and colour transparency. (orig.)
Thermally stimulated scattering in plasmas
DEFF Research Database (Denmark)
Dysthe, K. B.; Mjølhus, E.; Pécseli, H. L.;
1985-01-01
A theory for stimulated scattering of a laser beam is formulated where the dominant nonlinearity is the ohmic heating of the plasma. The analysis is carried out with particular reference to experimental investigations of CO2 laser heating of linear discharge plasma. In the conditions characterizing...
Scattering theory and automorphic functions
International Nuclear Information System (INIS)
After a consideration of the Fourier expansion of an automorphic function corresponding to the group SL(2,R) and a description of the Eisenstein series the author describes the application of these results to the quantum mechanical scattering theory using the group SO(2,R). (HSI)
Neutron scattering and models: Chromium
International Nuclear Information System (INIS)
Differential neutron elastic-scattering cross sections of elemental chromium are measured from 4.5 ∼ 10 MeV in steps of ∼ 0.5 MeV and at ≥ 40 scattering angles distributed between ∼ 17 degree--160 degree. Concurrently differential cross sections for the inelastic neutron excitation of the yrast 2+ (1.434 MeV) level in d52Cr are determined. In addition, broad inelastically-scattered neutron groups are observed corresponding to composite excitation of levels up to ∼ 5.5 MeV in the various chromium isotopes. These experimental results are combined with low-energy values previously reported from this laboratory, with recent ∼ 8 → 15 MeV data measured at the Physikalisch-Technische Bundesanstalt and with a 21.6 MeV result from the literature to form an extensive neutron-scattering data base which is interpreted in the context of spherical-optical and coupled-channels (rotational and vibrational) models. These models reasonably describe the observables but indicate rather large energy-dependent parameter trends at low energies similar to those previously reported near the peak of the So strength function in studies at this laboratory. The physical implications of the measurements and models are discussed including deformation, coupling, dispersive and asymmetry effects
Bibliography for thermal neutron scattering
International Nuclear Information System (INIS)
Bibliographic references are given for measurements, calculations, reviews and basic studies of thermal neutron scattering and dynamical properties of condensed matter. This is the sixth edition covering 3,326 articles collected up to 1978. The edition being the final issue of the present bibliography series, a forthcoming edition will be published in a new form of bibliography. (author)
International Nuclear Information System (INIS)
Aspects of the nuclear structure of 100Ru whe investigated by means of the scattering of 100Ru (p,p')100Ru* with 16 MeV protons, where 21 states were investigated. The emergent protons were analysed by a magnetic spectrograph, of the enge type with a typical resolution of ≅ 9 KeV. (A.C.A.S.)
Moliere's multiple scattering theory revisited
Voskresenskaya, O.; Tarasov, A.
2012-01-01
A part of Moliere's multiple scattering theory concerning the determination of the screening angular parameter is revised. An universal form of the Coulomb corrections to the screening angle, the exponential part of the distribution function, and the angular distribution is discussed within the small-angle approximation of this theory. The accuracy of the Moliere theory in determining the screening angle is estimated.
Neutron scattering science in Australia
Energy Technology Data Exchange (ETDEWEB)
Knott, Robert [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)
1999-10-01
Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)
Gravitational Laser Back-Scattering
Novaes, S. F.; Spehler, D.
1993-01-01
A possible way of producing gravitons in the laboratory is investigated. We evaluate the cross section electron + photon $\\rightarrow$ electron + graviton in the framework of linearized gravitation, and analyse this reaction considering the photon coming either from a laser beam or from a Compton back-scattering process.
Relativistic multiple scattering Xα calculations
International Nuclear Information System (INIS)
A one component relativistic theory has recently been developed and tested on isolated atoms and on molecules through the molecular scattered-wave formalism of Johnson, while its application to energy-band calculations (through a relativistic augmented-plane-wave program) has also been considered
Coupling between minimum scattering antennas
DEFF Research Database (Denmark)
Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans
1974-01-01
Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed......-dipoles and helices are considered in order to establish a correspondence with simple antenna structures....
Antiproton-Proton Glory Scattering
2002-01-01
This experiment measures @*p and K|-p backwards scattering between 8 and 16 GeV/c in the Omega spectrometer using the S1 beam, with sensitivities of several events per nanobarn. The mechanism responsible for backward scattering in channels not mediated by particle exchange is not understood, and could be almost energy-independent glory scattering, especially since relatively high cross sections of 190~(@*p) and 120~(K|-p)nb have been measured earlier at 5~GeV/c. @p|-p backwards scattering is measured for monitoring purposes. The trigger requires a forward particle of momentum close to the beam momentum. Absence of light in the two forward Cerenkov counters indicates that the particle is a proton. Combinations of an incident @p|- and an outgoing K|+, or an incident K|- or @* and an outgoing @p|+, cover the following byproducts: @*p~@A~@p|+@p|- which is an (allowed) baryon exchange reaction, and the exotic exchange reactions @p|-p~@A~K|+Y K|-p~@A~@p|+Y|-, where Y|- may be the @S|- or the Y*|-(1385).
Nuclear matter and electron scattering
Energy Technology Data Exchange (ETDEWEB)
Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)
1998-06-01
We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)
Neutron scattering science in Australia
International Nuclear Information System (INIS)
Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)
Spectroscopy, scattering, and KK molecules
International Nuclear Information System (INIS)
The author presents a pedagogical description of a new theoretical technique, based on the multichannel Schroedinger equation, for simultaneously applying the quark model to both meson spectroscopy and meson-meson scattering. This is an extension of an earlier analysis which led to the prediction that the fo(975) and ao(980) scalar mesons are K bar K molecular states
Neutron scattering and models: Silver
International Nuclear Information System (INIS)
Differential neutron elastic-scattering cross sections of elemental silver were measured from 1.5 → 10 MeV at ∼ 100 keV intervals up to 3 MeV, at ∼ 200 keV intervals from 3 → 4 MeV, and at ∼ 500 keV intervals above 4 MeV. At ≤ 4 MeV the angular range of the measurements was ∼ 200 → 1600 with 10 measured values below 3 MeV and 20 from 3 → 4 MeV at each incident energy. Above 4 MeV ≥ 40 scattering angles were used distributed between ∼ 170 and 160 All of the measured elastic distributions included some contributions due to inelastic scattering. Below 4 MeV the measurements determined cross sections for ten inelastically-scattered neutron groups corresponding to observed excitations of 328 ± 13, 419 ± 50, 748 ± 25, 908 ± 26, 115 ± 38, 1286 ± 25, 1507 ± 20, 1632 ± 30, 1835 ± 20 and 1944 ± 26 keV. All of these inelastic groups probably were composites of contributions from the two isotopes 107Ag and 109Ag. The experimental results were interpreted in terms of the spherical optical model and of rotational and vibrational coupled-channels models, and physical implications are discussed. In particular, the neutron-scattering results are consistent with a ground-state rotational band with a quadrupole deformation Β2 = 0.20 ± ∼ 10% for both of the naturally-occurring silver isotopes
Scatter networks: a new approach for analysing information scatter
International Nuclear Information System (INIS)
Information on any given topic is often scattered across the Web. Previously this scatter has been characterized through the inequality of distribution of facts (i.e. pieces of information) across webpages. Such an approach conceals how specific facts (e.g. rare facts) occur in specific types of pages (e.g. fact-rich pages). To reveal such regularities, we construct bipartite networks, consisting of two types of vertices: the facts contained in webpages and the webpages themselves. Such a representation enables the application of a series of network analysis techniques, revealing structural features such as connectivity, robustness and clustering. Not only does network analysis yield new insights into information scatter, but we also illustrate the benefit of applying new and existing analysis techniques directly to a bipartite network as opposed to its one-mode projection. We discuss the implications of each network feature to the users' ability to find comprehensive information online. Finally, we compare the bipartite graph structure of webpages and facts with the hyperlink structure between the webpages
Unparticle effects in photon-photon scattering
Chang, Chun-Fu; Cheung, Kingman; Yuan, Tzu-Chiang
2008-01-01
Elastic photon-photon scattering can only occur via loop diagrams in the standard model and is naturally suppressed. Unparticle can induce tree-level photon-photon scattering through the operator F_{\\mu\
Low-frequency limit of gravitational scattering
International Nuclear Information System (INIS)
We consider the low-frequency limit of cross sections for massless scalar, electromagnetic, and gravitational waves scattering on a Schwarzschild black hole. Explicit results are found for the scattering amplitudes, which differ from the Born approximation results
Time-Reversal Analysis for Scatterer Characterization
Energy Technology Data Exchange (ETDEWEB)
Chambers, D H; Berryman, J G
2003-11-05
Only the simplest monopole scattering behavior has usually been treated in previous time-reversal analyses. A new application of time-reversal processing of wave scattering data permits characterization of scatterers by analyzing the number and nature of the singular functions (or eigenfunctions) associated with individual scatterers when they have multiple contributions from monopole, dipole and/or quadrupole scattering terms. We discuss acoustic, elastic, and electromagnetic scattering problems for low frequencies (ka < 1, k being the wavenumber and a the radius of the scatterer). Specific examples for electromagnetic scattering from one of a number of small conducting spheres show that each sphere can have up to six distinct time-reversal eigenfunctions associated with it.
Nitrogen Contamination in Elastic Neutron Scattering
Chi, Songxue; Lynn, Jeffrey W.; Chen, Ying; Ratcliff II, William; Ueland, Benjamin G.; Butch, Nicholas P.; Saha, Shanta R.; Kirshenbaum, Kevin; Paglione, Johnpierre
2011-01-01
Nitrogen gas accidentally sealed in a sample container produces various spurious effects in elastic neutron scattering measurements. These effects are systematically investigated and the details of the spurious scattering are presented.
Advantages of neutron scattering for biological structure analysis
International Nuclear Information System (INIS)
The advantages and disadvantages of neutron scattering for protein crystallography, scattering from oriented systems, and solution scattering are summarized. Techniques for minimizing the disadvantages are indicated
Scattered X-ray beam nondestructive testing
Harding, G.; Kosanetzky, J.
1989-08-01
X-ray scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered.
Spatial photon correlations in multiple scattering media
DEFF Research Database (Denmark)
Smolka, Stephan; Muskens, O.; Lagendijk, A.;
2010-01-01
We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations.......We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations....
Low energy electron scattering from polyatomic targets
Energy Technology Data Exchange (ETDEWEB)
Khakoo, Murtadha A; Muse, John; Campbell, Colin [Department of Physics, California State University, Fullerton, CA 92834 (United States); Lopes, Maria Cristina A; Silva, Helen [Departamento de Fisica, ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, CEP 36036-330 (Brazil); Winstead, Carl; McKoy, Vincent, E-mail: mkhakoo@fullerton.ed [A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)
2009-11-15
Low energy elastic electron scattering cross-sections from water and several alcohols are presented. This paper addresses accurately measuring quantitative differential elastic scattering cross-sections, using the relative flow method with an aperture source, and focuses on the long range dipole interaction of the scattering electron with these polar targets. The electron-dipole interaction dominates the scattering for these molecules and contributes significantly to their integral elastic cross-sections.
Neutron scattering studies in the actinide region
International Nuclear Information System (INIS)
This report discusses the following topics: Prompt fission neutron energy spectra for 235U and 239Pu; Two-parameter measurement of nuclear lifetimes; ''Black'' neutron detector; Data reduction techniques for neutron scattering experiments; Inelastic neutron scattering studies in 197Au; Elastic and inelastic scattering studies in 239Pu; and neutron induced defects in silicon dioxide MOS structures
Scattering of entangled two-photon states
Schotland, John C; Norris, Theodore B
2015-01-01
We consider the scattering of entangled two-photon states from collections of small particles. We also study the related Mie problem of scattering from a sphere. In both cases, we calculate the entropy of entanglement and investigate the influence of the entanglement of the incident field on the entanglement of the scattered field.
Multiple scattering Model in GEANT4
Urbàn, L
2002-01-01
We present a new multiple scattering (MSC) model to simulate the multiple scattering of charged particles in matter. This model does not use the Moliere formalism, it is based on the more complete Lewis theory. The model simulates the scattering of the particle after a given step, computes the path length correction and the lateral displacement as well.
Recent development in magnetic neutron scattering studies
International Nuclear Information System (INIS)
Neutron scattering results contain many new concepts in modern magnetism. We review here the most recent neutron magnetic scattering studies from so called '214' copper oxide lamellar materials, because a number of important developments in magnetism are condensed in this novel subject. We show that neutron scattering has played crucial role in our understanding of modern magnetism. (author)
Perspectives in electron scattering and nuclear structure
International Nuclear Information System (INIS)
The author discusses theoretically nuclear-structure studies by elastic electron scattering. He discusses the nuclear form factor and meson-exchange currents. Finally he considers the tensor analyzing power in elastic eD scattering, the neutron electric form factor, and parity violating electron scattering in the framework of the Weinberg-Salam theory. (HSI)
Elastic Scattering Properties of Ultracold Strontium Atoms
Institute of Scientific and Technical Information of China (English)
张计才; 朱遵略; 刘玉芳; 孙金锋
2011-01-01
We investigate the elastic scattering properties of strontium atoms at ultracold temperatures.The scattering parameters,such as s-wave scattering lengths,effective ranges and p-wave scattering lengths,are calculated for all stable isotope combinations of Sr atoms by the quantal method and semiclassical method,respectively.Good agreements are obtained.The scattering parameters are very sensitive to small changes of the reduced mass.Due to the repulsive interisotope and intraisotope s-wave scattering length and large elastic cross sections,84Sr-86Srmixture is a good candidate to realize Bose-Bose quantum degenerate atomic gases.%We investigate the elastic scattering properties of strontium atoms at ultracold temperatures. The scattering parameters, such as s-wave scattering lengths, effective ranges and p-wave scattering lengths, are calculated for all stable isotope combinations of Sr atoms by the quantal method and semiclassical method, respectively. Good agreements are obtained. The scattering parameters are very sensitive to small changes of the reduced mass. Due to the repulsive interisotope and intraisotope s-wave scattering length and large elastic cross sections, MSr-s(iSr mixture is a good candidate to realize Bose-Bose quantum degenerate atomic gases.
Scattering of pions from light nuclei
International Nuclear Information System (INIS)
The elastic scattering of pions from 6Li, 12,14C, 15N and 16O are studied in terms of the strong absorption model of Frahn and Venter. The parameters thus obtained are used to study the inelastic scattering of pions from 12,14C. An overall fair agreement is obtained in most cases for both elastic and inelastic scattering
Shear Brillouin light scattering microscope.
Kim, Moonseok; Besner, Sebastien; Ramier, Antoine; Kwok, Sheldon J J; An, Jeesoo; Scarcelli, Giuliano; Yun, Seok Hyun
2016-01-11
Brillouin spectroscopy has been used to characterize shear acoustic phonons in materials. However, conventional instruments had slow acquisition times over 10 min per 1 mW of input optical power, and they required two objective lenses to form a 90° scattering geometry necessary for polarization coupling by shear phonons. Here, we demonstrate a confocal Brillouin microscope capable of detecting both shear and longitudinal phonons with improved speeds and with a single objective lens. Brillouin scattering spectra were measured from polycarbonate, fused quartz, and borosilicate in 1-10 s at an optical power level of 10 mW. The elastic constants, phonon mean free path and the ratio of the Pockels coefficients were determined at microscopic resolution. PMID:26832263
Hard exclusive scattering in QCD
Gousset, T; Gousset, Thierry; Pire, Bernard
1995-01-01
We review the theory of hard exclusive scattering in Quantum Chromodynamics. After recalling the classical counting rules which describe the leading scale dependence of form factors and elastic reactions at fixed angle, the pedagogical example of the pion form factor is developped in some detail in order to show explicitely what factorization means in the QCD framework. The inclusion of transverse degrees of freedom leads to the discussion of Sudakov effects which are crucial for protecting the calculation from dangerous infrared regions. The picture generalizes to many hard reactions; a strategy to extract distribution amplitudes from future data is sketched. We discuss also the particular case of hadron-hadron collisions where the independent scattering mechanism dominates asymptotically and where a different factorization formula applies. We briefly present the concepts of color transparency and nuclear filtering and critically discuss the few present data on this subject.
International Nuclear Information System (INIS)
The availability of tunable synchrotron radiation has made it possible systematically to perform x-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g. in order to derive phase information for crystal structure determination. An overview is given of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L3 edge in a cesium complex. Also given is an overview of elements and levels where similar behavior can be expected. Finally, the influence of solid state and chemical effects on the absorption edge structure is discussed. 64 references
Scattering characteristics from porous silicon
Directory of Open Access Journals (Sweden)
R. Sabet-Dariani
2000-12-01
Full Text Available Porous silicon (PS layers come into existance as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet. In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from PS and the origin of its photoluminescence are reveiwed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include,different methods of PS sample preparation their photoluminescence, reflecting and scattering of light determining different characteristics with respect to Si bulk.
Brillouin scattering self-cancellation
Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.
2016-06-01
The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.
Neutrino scattering with CHARM II
International Nuclear Information System (INIS)
The latest result of the CHARM II experiment is presented. A determination of the neutral current coupling constants gVe and gAe from a study of the differential cross sections of (anti)muon-neutrino electron scattering. The analysis is based on data taken in the years 1987 to 1990 with the CHARM II detector which was exposed to the CERN wide band neutrino beam. A total of about 2100 νe and 2200 ν-bare scattering events were observed. Comparing the distributions of kinematic variables of these events to the predicted distributions the effective vector and axial-vector neutral current coupling constants of the electron are determined to be gVe=-0.025±0.019 and gAe=-0.503±0.018. (author) 10 refs.; 2 figs.; 3 tabs
Track fitting with multiple scattering
International Nuclear Information System (INIS)
An analytical calculation of the variance is performed, in some simple cases, for standard least-squares estimators of track parameters (accounting for independent measurement errors only); comparison is made with optimal estimators (accounting also for scattering errors, correlated between one point and the following ones). A new method is proposed for optimal estimation: the points measured on the track are included backwards, one by one, in the fitting algorithm, and the scattering is handled locally at each step. The feasibility of the method is shown on real events, for which the geometrical resolution is improved. The algorithm is very flexible and allows fast programmation; moreover the computation time is merely proportional to the number of measured points, contrary to the other optimal estimators. (orig.)
Scattering amplitudes in gauge theories
Henn, Johannes M
2014-01-01
At the fundamental level, the interactions of elementary particles are described by quantum gauge field theory. The quantitative implications of these interactions are captured by scattering amplitudes, traditionally computed using Feynman diagrams. In the past decade tremendous progress has been made in our understanding of and computational abilities with regard to scattering amplitudes in gauge theories, going beyond the traditional textbook approach. These advances build upon on-shell methods that focus on the analytic structure of the amplitudes, as well as on their recently discovered hidden symmetries. In fact, when expressed in suitable variables the amplitudes are much simpler than anticipated and hidden patterns emerge. These modern methods are of increasing importance in phenomenological applications arising from the need for high-precision predictions for the experiments carried out at the Large Hadron Collider, as well as in foundational mathematical physics studies on the S-matrix in quantum ...
Brillouin Scattering Self-Cancellation
Florez, Omar; Espinel, Yovanny A V; Cordeiro, Cristiano M B; Alegre, Thiago P Mayer; Wiederhecker, Gustavo S; Dainese, Paulo
2016-01-01
The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result proper material and structure engineering allows one to control each contribution individually. In this paper, we experimentally demonstrate the perfect cancellation of Brillouin scattering by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancin...
SCATTERING FUNCTION OF POLYMER BLENDS
Institute of Scientific and Technical Information of China (English)
Lin-ping Ke; Mei-li Guo; De-lu Zhao
2004-01-01
For a system of flexible polymer molecules, the concepts of two concentrations, namely the segmental and the molecular concentrations, have been proposed in this paper. The former is equivalent to the volume fraction. The latter can be defined as the number of the gravity centers of macromolecules in a unit volume. The two concentrations should be correlated with each other by the conformational function of the polymer chain and should be discussed in different thermodynamic equations. On the basis of these concepts it has been proved that the Flory-Huggins entropy of mixing should be the result of the mixing "ideal gases of the gravity centers of macromolecules". The general correlation between the free energy of mixing and the scattering function (structural factor) of polymer blends has been studied based on the general fluctuation theory. When the Flory-Huggins free energy of mixing is adopted, the de Gennes scattering function of a polymer blend can be derived.
Vector Boson Scattering at ATLAS
Ozcan, V E
2009-01-01
While the Higgs model is the best studied scenario of electroweak symmetry breaking, there is no fundamental reason for the physics responsible for the symmetry breaking to be weakly-coupled. Many alternatives exist, predicting highly model-dependent signatures. By measuring the cross-section for the W and Z scattering at the LHC, it will be possible to obtain model-independent evidence for strong symmetry breaking or to constrain these various models. ATLAS Collaboration has recently performed a realistic simulation of this process and its backgrounds, which takes into account the detector effects and has developed new jet-analysis techniques for identifying vector bosons within the immense QCD backgrounds expected at the LHC. These techniques and the prospects for measuring the scattering signal will be presented.
Scattering characteristics from porous silicon
International Nuclear Information System (INIS)
Porous silicon layers come into existence as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet. In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from porous silicon and the origin of its photoluminescence are reviewed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include: different methods of porous silicon sample preparation; their photoluminescence, reflecting and scattering of light; determining different characteristics with respect to Si bulk
Diffraction in Deep Inelastic Scattering
Hebecker, A
2000-01-01
Different theoretical methods used for the description of diffractive processes in small-x deep inelastic scattering are reviewed. The semiclassical approach, where a partonic fluctuation of the incoming virtual photon scatters off a superposition of target colour fields, is used to explain the basic physical effects. In this approach, diffraction occurs if the emerging partonic state is in a colour singlet, thus fragmenting independently of the target. Other approaches, such as the idea of the pomeron structure function and two gluon exchange calculations, are also discussed in some detail. Particular attention is paid to the close relation between the semiclassical approach and the method of diffractive parton distributions, which is linked to the relation between the target rest frame and the Breit frame point of view. While the main focus is on diffractive structure functions, basic issues in the diffractive production of mesons and of other less inclusive final states are also discussed. Models of the pr...
Entanglement quantification by neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Marty, Oliver; Plenio, Martin; Cramer, Marcus [Institut fuer Theoretische Physik, Universtitaet Ulm, Ulm (Germany); Epping, Michael; Kampermann, Hermann; Bruss, Dagmar [Institut fuer Theoretische Physik III, Heinrich-Heine Universitaet Duesseldorf, Duesseldorf (Germany)
2013-07-01
We present studies about the quantification of the entanglement contained in large samples of magnetic materials by structure factor measurements - a standard tool in analyzing condensed matter systems. We discuss experimentally relevant models (such as Heisenberg, Majumdar-Ghosh and XY models) in different geometries and with different spin numbers. For those, lower bounds to entanglement measures can be read off directly from the cross section obtained in neutron-scattering experiments.
Polarized triton elastic scattering data
International Nuclear Information System (INIS)
Different-cross-section and analyzing-power angular distrbutions were measured for 17-MeV polarized triton elastic scattering. The 13 target nuclei spanned the range 40 less than or equal to A less than or equal to 208, and the angular range was 200 less than or equal to THETA less than or equal to 1600. The data are presented in tables and graphs. 8 references
Spectroscopy, scattering, and KK molecules
Energy Technology Data Exchange (ETDEWEB)
Weinstein, J. [Univ. of Mississippi, University, MS (United States)
1994-04-01
The author presents a pedagogical description of a new theoretical technique, based on the multichannel Schroedinger equation, for simultaneously applying the quark model to both meson spectroscopy and meson-meson scattering. This is an extension of an earlier analysis which led to the prediction that the f{sub o}(975) and a{sub o}(980) scalar mesons are K{bar K} molecular states.
Primakoff effect in electron scattering
International Nuclear Information System (INIS)
The lifetime of π0 and other pseudoscalar mesons, has been successfully investigated in the past by means of the Primakoff effect, i.e., the production of neutral mesons by incident photons interacting with the Coulomb field of a high Z nucleus. In the present work, the same phenomenon is explored, initiated by virtual, rather than real, photons from electron scattering. Experimental measurements, if feasible, will provide valuable formation about the structure of the γπ0 vertex
Neutron Scattering Studies of Cement
Allen, Andrew
2010-03-01
Despite more than a century of research, basic questions remain regarding both the internal structure and the role of water in Ordinary Portland cement (OPC) concrete, the world's most widely used manufactured material. Most such questions concern the primary hydration product and strength-building phase of OPC paste, the calcium silicate hydrate (C-S-H) gel. When cement and water are mixed, this phase precipitates as clusters of nanoscale (nearly amorphous) colloidal particles with an associated water-filled inter-particle pore system. Most attempts to characterize the C-S-H gel and the behavior of the associated water involve drying or other processes that, themselves, change the bound water content within and around the gel. Neutron scattering methods do not suffer from this disadvantage. Furthermore, the neutron isotope effect and the neutron's sensitivity to molecular motion have enabled considerable progress to be made in recent years by: (i) determining the C-S-H composition, density and gel structure in small-angle neutron scattering (SANS) H/D contrast variation studies; (ii) elucidating the changing state of water within cement as hydration progresses using quasielastic neutron scattering (QENS); and (iii) measuring the production and consumption of nanoscale calcium hydroxide (CH), a by-product of cement hydration that co-exists with the C-S-H gel, using inelastic neutron scattering (INS). These experiments have provided new insights into the physics and chemistry of cement hydration, and have implications for the design of new concretes with pozzolanic cement additions that are intended to address environmental concerns and sustainability issues.
Compton scattering in strong gravity
Czech Academy of Sciences Publication Activity Database
Bursa, Michal; Adámek, K.
Opava: Silesian University, 2014 - (Stuchlík, Z.), S.31-37. (Publications of the Institute of Physics. 7). ISBN 9788075101266. ISSN 2336-5668. [RAGtime /14.-16./. Opava (CZ), 18.09.2012-22.09.2012] R&D Projects: GA MŠk(CZ) LH14049 Institutional support: RVO:67985815 Keywords : radiation transport * relativity * Compton scattering Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Proton scattering from unstable nuclei
Indian Academy of Sciences (India)
Y Blumenfeld; E Khan; F Maréchal; T Suomijärvi
2001-08-01
Recent improvements in the intensities and optical qualities of radioactive beams have made possible the study of elastic and inelastic proton scattering on unstable nuclei. The design and performances of an innovative silicon strip detector array devoted to such experiments are described. The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes. Methods to analyse the data using phenomenological and microscopic optical model potentials are discussed.
Decoherence due to Scattering Atoms
Uys, Hermann; Perreault, John; Cronin, Alex
2004-05-01
Coherent manipulation of a quantum system is difficult because of uncontrolled interactions with the system's environment. The study of decoherence so introduced is important for progress in quantum mechanical engineering, and for understanding the transition from quantum to classical behavior. We have observed loss of fringe contrast in a Mach-Zhender atom interferometer due to scattering background gas atoms and propose that this might be interpreted as quantum decoherence. Progress will be reported on the use of a general model of decoherence incorporating a semi-classical picture of atom scattering to explain the contrast loss [1]. A formal analogy is made to decoherence due to scattering photons from atoms in an interferometer [2]. [1] S.M. Tan, D.F. Waals, ``Loss of coherence in interferometry", Phys. Rev. A 47 p.4663 (1993) [2] D.A. Kokorowski, A.D. Cronin, T.D. Roberts, and D.E. Pritchard, ``From single- to multiple-photon decoherence in an atom interferometer", Phys. Rev. Lett. 86 p. 2191 (2001)
Glory scattering by black holes
International Nuclear Information System (INIS)
We present a physically motivated derivation of the JWKB backward glory-scattering cross section of massless waves by Schwarzschild black holes. The angular dependence of the cross section is identical with the one derived by path integration, namely, dsigma/dΩ = 4π2lambda-1B/sub g/ 2(dB mWπ, where lambda is the wavelength, B(theta) is the inverse of the classical deflection function CTHETA(B), B/sub g/ is the glory impact parameter, s is the helicity of the scattered wave, and J/sub 2s/ is the Bessel function of order 2s. The glory rings formed by scalar waves are bright at the center; those formed by polarized waves are dark at the center. For scattering of massless particles by a spherical black hole of mass M, B(theta)/Mapprox.3 √3 + 3.48 exp(-theta), theta > owigπ. The numerical values of dsigma/dΩ for this deflection function are found to agree with earlier computer calculations of glory cross sections from black holes
Scattering zippers and their spectral theory
Marin, Laurent
2011-01-01
A scattering zipper is a system obtained by concatenation of scattering events with equal even number of incoming and out going channels. The associated scattering zipper operator is the unitary equivalent of Jacobi matrices with matrix entries and generalizes Blatter-Browne and Chalker-Coddington models and CMV matrices. Weyl discs are analyzed and used to prove a bijection between the set of semi-infinite scattering zipper operators and matrix valued probability measures on the unit circle. Sturm-Liouville oscillation theory is developed as a tool to calculate the spectra of finite and periodic scattering zipper operators.
Wave propagation and scattering in random media
Ishimaru, Akira
1978-01-01
Wave Propagation and Scattering in Random Media, Volume 2, presents the fundamental formulations of wave propagation and scattering in random media in a unified and systematic manner. The topics covered in this book may be grouped into three categories: waves in random scatterers, waves in random continua, and rough surface scattering. Random scatterers are random distributions of many particles. Examples are rain, fog, smog, hail, ocean particles, red blood cells, polymers, and other particles in a state of Brownian motion. Random continua are the media whose characteristics vary randomly an
Speckles in interstellar radio-wave scattering
Desai, K. M.; Gwinn, C. R.; Reynolds, J.; King, E. A.; Jauncey, D.; Nicholson, G.; Flanagan, C.; Preston, R. A.; Jones, D. L.
1991-01-01
Observations of speckles in the scattering disk of the Vela pulsar are presented and speckle techniques for studying and circumventing scattering of radio waves by the turbulent interstellar plasma are discussed. The speckle pattern contains, in a hologrammatic fashion, complete information on the structure of the radio source as well as the distribution of the scattering material. Speckle observations of interstellar scattering of radio waves are difficult because of their characteristically short timescales and narrow bandwidths. Here, first observations are presented, taken at 13 cm wavelength with elements of the SHEVE VLBI network, of speckles in interstellar scattering.
Hybrid scatter correction for CT imaging
International Nuclear Information System (INIS)
The purpose of this study was to develop and evaluate the hybrid scatter correction algorithm (HSC) for CT imaging. Therefore, two established ways to perform scatter correction, i.e. physical scatter correction based on Monte Carlo simulations and a convolution-based scatter correction algorithm, were combined in order to perform an object-dependent, fast and accurate scatter correction. Based on a reconstructed CT volume, patient-specific scatter intensity is estimated by a coarse Monte Carlo simulation that uses a reduced amount of simulated photons in order to reduce the simulation time. To further speed up the Monte Carlo scatter estimation, scatter intensities are simulated only for a fraction of all projections. In a second step, the high noise estimate of the scatter intensity is used to calibrate the open parameters in a convolution-based algorithm which is then used to correct measured intensities for scatter. Furthermore, the scatter-corrected intensities are used in order to reconstruct a scatter-corrected CT volume data set. To evaluate the scatter reduction potential of HSC, we conducted simulations in a clinical CT geometry and measurements with a flat detector CT system. In the simulation study, HSC-corrected images were compared to scatter-free reference images. For the measurements, no scatter-free reference image was available. Therefore, we used an image corrected with a low-noise Monte Carlo simulation as a reference. The results show that the HSC can significantly reduce scatter artifacts. Compared to the reference images, the error due to scatter artifacts decreased from 100% for uncorrected images to a value below 20% for HSC-corrected images for both the clinical (simulated data) and the flat detector CT geometry (measurement). Compared to a low-noise Monte Carlo simulation, with the HSC the number of photon histories can be reduced by about a factor of 100 per projection without losing correction accuracy. Furthermore, it was sufficient to
Modelling Dust Scattering in our Galaxy
Murthy, Jayant
2016-01-01
I have used a Monte Carlo model for dust scattering in our Galaxy with multiple scattering to study the diffuse emission seen by the \\galex\\ mission. I find that the emission at low and mid latitudes is fit well by scattering from dust grains with an albedo of 0.4 and $g = 0$ (isotropically scattering grains). However, only about 30\\%\\ of the diffuse radiation at high Galactic latitudes is due to dust scattering. There is an additional component of 500 - 600 photons cm$^{-2}$ s$^{-1}$ sr$^{-1}$ \\AA$^{-1}$ at all latitudes of an unknown origin.
Cascades of Fano resonances in Mie scattering
Rybin, M. V.; Sinev, I. S.; Samusev, K. B.; Limonov, M. F.
2014-03-01
The interference nature of resonant Mie scattering, which is described within the Fano model, has been demonstrated. The interference is caused by interaction of an incident electromagnetic wave with reemitted waves that correspond to eigenmodes of a scattering particle. Mie scattering due to the interference can be represented in the form of cascades of resonance lines of different shapes, each of which is described by the classical Fano formula. The effect is observed in resonant light scattering by an arbitrary body of revolution and discussed in detail using the example of scattering by an infinite homogeneous dielectric cylinder.
Rotational raman lidar for aerosol scattering coefficients
International Nuclear Information System (INIS)
Two channel lidar signals which are composed of the total rotational scattering and elastic signals provide good information for the aerosol scattering coefficients. We can calculate the aerosol backscattering coefficient and extinction coefficient directly without any assumption and calibration process. Generally, a high spectral resolution lidar is used for an aerosol monitoring. But we have designed a new normal spectral receiving lidar system which contains the scattering information simultaneously, and we have retrieved the aerosol scattering coefficient. The results show that there is no need to assume any relation between the aerosol backscattering and extinction and to consider any wavelength calibration process for the aerosol scattering coefficient
Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit
Pine, D. J.; Weitz, D. A.; Zhu, J.X.; Herbolzheimer, E.
1990-01-01
Dynamic light scattering is extended to optically thick (opaque) media which exhibit a very high degree of multiple scattering. This new technique, called diffusing-wave spectroscopy (DWS), exploits the diffusive nature of the transport of light in strongly scattering media to relate the temporal fluctuations of the multiply scattered light to the motion of the scatterers. A simple theory of DWS, based on the diffusion approximation for the transport of light, is developed to calculate the te...
Disentangling correlated scatter in cluster mass measurements
Noh, Yookyung
2012-01-01
The challenge of obtaining galaxy cluster masses is increasingly being addressed by multiwavelength measurements. As scatters in measured cluster masses are often sourced by properties of or around the clusters themselves, correlations between mass scatters are frequent and can be significant, with consequences for errors on mass estimates both directly and those obtained via stacking. Using a high resolution 250 Mpc/h side N-body simulation, combined with proxies for observational cluster mass measurements, we obtain mass scatter correlations and covariances for 243 individual clusters along ~96 lines of sight each, both separately and together. We use principal component analysis (PCA) to characterize scatter trends and variations between clusters. The dominant mass scatter combination identified by PCA is common to many clusters, and tends to dominate the mass scatters when viewing the cluster along its long axis. We also correlate cluster mass scatter, environmental and intrinsic properties, and use PCA t...
Source distribution dependent scatter correction for PVI
International Nuclear Information System (INIS)
Source distribution dependent scatter correction methods which incorporate different amounts of information about the source position and material distribution have been developed and tested. The techniques use image to projection integral transformation incorporating varying degrees of information on the distribution of scattering material, or convolution subtraction methods, with some information about the scattering material included in one of the convolution methods. To test the techniques, the authors apply them to data generated by Monte Carlo simulations which use geometric shapes or a voxelized density map to model the scattering material. Source position and material distribution have been found to have some effect on scatter correction. An image to projection method which incorporates a density map produces accurate scatter correction but is computationally expensive. Simpler methods, both image to projection and convolution, can also provide effective scatter correction
Neutron Inelastic Scattering Study of Liquid Argon
International Nuclear Information System (INIS)
The inelastic scattering functions for liquid argon have been measured at 85.2 K. The coherent scattering function was obtained from a measurement on pure A-36 and the incoherent function was derived from the result obtained from the A-36 sample and the result obtained from a mixture of A-36 and A-40 for which the scattering is predominantly incoherent. The data, which are presented as smooth scattering functions at constant values of the wave vector transfer in the range 10 - 44/nm, are corrected for multiple scattering contributions and for resolution effects. Such corrections are shown to be essential in the derivation of reliable scattering functions from neutron scattering data. The incoherent data are compared to recent molecular dynamics results and the mean square displacement as a function of time is derived. The coherent data are compared to molecular dynamics results and also, briefly, to some recent theoretical models
Positronium and Electron Scattering on Helium
DiRienzi, Joseph
2011-01-01
A recent work [1] establishes experimentally that Positronium scattering by atoms of various elements is surprisingly close in total cross-section to that of an isolated electron of the same velocity. In this work we will look at the scattering of Ps on Helium and compare it to a determination of the scattering of an e- with the same element. For both the Ps scattering and the e- scattering on He, we assume the symmetrization of the e- with the closed shell He electrons is the dominant interaction. A local effective potential employed in [2] and [3] is used to model the electron exchange and cross- sections are determined for a set of partial waves. For the Ps scattering we include as a secondary effect the Van der Waals interaction. For single e- scattering of He, we also employ a short range Coulomb potential and dispersion as contributing effects. Results of the cross-sections determined in each case are then compared
Striped ratio grids for scatter estimation
Hsieh, Scott S.; Wang, Adam S.; Star-Lack, Josh
2016-03-01
Striped ratio grids are a new concept for scatter management in cone-beam CT. These grids are a modification of conventional anti-scatter grids and consist of stripes which alternate between high grid ratio and low grid ratio. Such a grid is related to existing hardware concepts for scatter estimation such as blocker-based methods or primary modulation, but rather than modulating the primary, the striped ratio grid modulates the scatter. The transitions between adjacent stripes can be used to estimate and subtract the remaining scatter. However, these transitions could be contaminated by variation in the primary radiation. We describe a simple nonlinear image processing algorithm to estimate scatter, and proceed to validate the striped ratio grid on experimental data of a pelvic phantom. The striped ratio grid is emulated by combining data from two scans with different grids. Preliminary results are encouraging and show a significant reduction of scatter artifact.
Zhang, Lu; Chen, Xingyu; Zhang, Zhenxi; Chen, Wei; Zhao, Hong; Zhao, Xin; Li, Kaixing; Yuan, Li
2016-04-01
Scattering pulse is sensitive to the morphology and components of each single label-free cell. The most direct detection result, label free cell's scattering pulse is studied in this paper as a novel trait to recognize large malignant cells from small normal cells. A set of intrinsic scattering pulse calculation method is figured out, which combines both hydraulic focusing theory and small particle's scattering principle. Based on the scattering detection angle ranges of widely used flow cytometry, the scattering pulses formed by cell scattering energy in forward scattering angle 2°-5° and side scattering angle 80°-110° are discussed. Combining the analysis of cell's illuminating light energy, the peak, area, and full width at half maximum (FWHM) of label free cells' scattering pulses for fine structure cells with diameter 1-20 μm are studied to extract the interrelations of scattering pulse's features and cell's morphology. The theoretical and experimental results show that cell's diameter and FWHM of its scattering pulse agree with approximate linear distribution; the peak and area of scattering pulse do not always increase with cell's diameter becoming larger, but when cell's diameter is less than about 16 μm the monotone increasing relation of scattering pulse peak or area with cell's diameter can be obtained. This relationship between the features of scattering pulse and cell's size is potentially a useful but very simple criterion to distinguishing malignant and normal cells by their sizes and morphologies in label free cells clinical examinations.
PREFACE: Atom-surface scattering Atom-surface scattering
Miret-Artés, Salvador
2010-08-01
It has been a privilege and a real pleasure to organize this special issue or festschrift in the general field of atom-surface scattering (and its interaction) in honor of J R Manson. This is a good opportunity and an ideal place to express our deep gratitude to one of the leaders in this field for his fundamental and outstanding scientific contributions. J R Manson, or Dick to his friends and colleagues, is one of the founding fathers, together with N Cabrera and V Celli, of the 'Theory of surface scattering and detection of surface phonons'. This is the title of the very well-known first theoretical paper by Dick published in Physical Review Letters in 1969. My first meeting with Dick was around twenty years ago in Saclay. J Lapujoulade organized a small group seminar about selective adsorption resonances in metal vicinal surfaces. We discussed this important issue in surface physics and many other things as if we had always known each other. This familiarity and warm welcome struck me from the very beginning. During the coming years, I found this to be a very attractive aspect of his personality. During my stays in Göttingen, we had the opportunity to talk widely about science and life at lunch or dinner time, walking or cycling. During these nice meetings, he showed, with humility, an impressive cultural background. It is quite clear that his personal opinions about history, religion, politics, music, etc, come from considering and analyzing them as 'open dynamical systems'. In particular, with good food and better wine in a restaurant or at home, a happy cheerful soirée is guaranteed with him, or even with only a good beer or espresso, and an interesting conversation arises naturally. He likes to listen before speaking. Probably not many people know his interest in tractors. He has an incredible collection of very old tractors at home. In one of my visits to Clemson, he showed me the collection, explaining to me in great detail, their technical properties
Time delay in quantum scattering
International Nuclear Information System (INIS)
As is well known, the knowledge of the scattering cross section and its angular dependence, as a function of energy, is insufficient to determine the phase shifts uniquely. This led Eisenbud and Wigner to propose the measurement of the scattering lifetime or time delay as an additional independent datum. A rigorous time-dependent study of time delay within the framework of Hilbert space formalism is presented. Specifically, Martin's theory of time delay and the validity of the Eisenbud-Wigner time delay formula are extended to spherically symmetric potentials satisfying the asymptotic fall-off rate V(r) → O(r/sup -2-epsilon/). This extension is obtained by use of a maximal estimate of the rate of convergence of the asymptotic condition and the elimination of Martin's requirement that the scattering operator S be three times differentiable with respect to the free-particle Hamiltonian H0. Also presented are related results on the total time a quantum particle spends inside some bounded regions in position space. It is then proved that any two free particles having identical distributions of energy and angular momentum take exactly identical expectation values for the transit time across an arbitrary spherical region centered at the origin in position space. Ways to extend this result to nonfree Hamiltonians are indicated. Finally, the relationship between the position operator and the Eisenbud-Wigner time delay operator is examined. It is shown that the usual method of calculating time delay based on the classical analysis of the position operator is not exact
Inelastic scattering from amorphous solids
International Nuclear Information System (INIS)
The potential of inelastic neutron scattering techniques for surveying various aspects of the dynamics of amorphous solids is briefly reviewed. The recent use of the Intense Pulsed Neutron Source to provide detailed information on the optical vibrations of glasses is discussed in more detail. The density of states represents an averaged quantity which gives information about the general characteristics of the structure and bonding. More extensive information can be obtained by studying the detailed wavevector dependence of the dynamic structure factor. 15 refs., 7 figs
Neutron scattering from a ferrofluid
International Nuclear Information System (INIS)
Small angle neutron scattering experiments were performed on a eicosane-based ferrofluid. An average size of 88 angstrom can be extracted from the data, in agreement with results from electron microscopy. Below the frozen temperature of eicosane, however, the particles are seen to be in larger aggregates with a fractal dimension of 2.15, similar to those formed under reaction-limited cluster aggregation (RLCA) conditions. At high concentrations, particles form larger aggregates even in the liquid state. Applying a magnetic field introduces new structure and changes the density inside the aggregates
Small angle scattering and polymers
International Nuclear Information System (INIS)
The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs
Moliere multiple scattering theory revisited
Tarasov, Alexander
2012-01-01
We have received the rigorous relations between the screening parameters of the Moliere multiple scattering theory, instead of the approximate one obtained in the original paper by Moliere. We also calculated the relative Coulomb corrections to the first Born screening angle in the range from Z=4 to Z=82, and showed that their maximum values comprise the order of 40 percent. Additionally, we evaluated absolute and relative accuracies of the Moliere theory in determining the screening angle and have concluded that for Z~80 they are about 20, and 34 percents, respectively.
Small angle scattering and polymers
Energy Technology Data Exchange (ETDEWEB)
Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1996-12-31
The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.
Calculation of thermal diffuse scattering
Wakabayashi, N.; Nicklow, R. M.; Katano, S.; Ishii, Y.; Child, H. R.; Smith, H. G.; Fernandez-Baca, J. A.
We have developed a computer program to calculate the thermal diffuse scattering (TDS) intensity distribution for single-crystal specimens in a diffractometer with no energy analysis. We assumed that the phonon frequencies are approximated by those of elastic waves and that the elastic constants, density and lattice parameters of the system under study are known. The results of the calculations were compared to experimental data obtain for single crystals of Si, diamond and NiAl at the wide-angle neutron diffractometer (WAND) at the HFIR at Oak Ridge National Laboratory. Excellent agreement was found between the calculations and the experimental observations.
Calculation of thermal diffuse scattering
International Nuclear Information System (INIS)
The authors developed a computer program to calculate the thermal diffuse scattering (TDS) intensity distribution for single crystal specimens in a diffractometer with no energy analysis. They assumed that the phonon frequencies are approximated by those of elastic waves and that the elastic constants, density and lattice parameters of the system under study are known. The results of the calculations were compared to experimental data obtained for single crystals of Si, diamond and NiAl at the Wide Angle neutron Diffractometer at the HFIR at Oak Ridge National Laboratory. Excellent agreement was found between the calculations and the experimental observations
Light scattering near phase transitions
Cummins, HZ
1983-01-01
Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.
International Nuclear Information System (INIS)
As gas giant planets evolve, they may scatter other planets far from their original orbits to produce hot Jupiters or rogue planets that are not gravitationally bound to any star. Here, we consider planets cast out to large orbital distances on eccentric, bound orbits through a gaseous disk. With simple numerical models, we show that super-Earths can interact with the gas through dynamical friction to settle in the remote outer regions of a planetary system. Outcomes depend on planet mass, the initial scattered orbit, and the evolution of the time-dependent disk. Efficient orbital damping by dynamical friction requires planets at least as massive as the Earth. More massive, longer-lived disks damp eccentricities more efficiently than less massive, short-lived ones. Transition disks with an expanding inner cavity can circularize orbits at larger distances than disks that experience a global (homologous) decay in surface density. Thus, orbits of remote planets may reveal the evolutionary history of their primordial gas disks. A remote planet with an orbital distance ∼100 AU from the Sun is plausible and might explain correlations in the orbital parameters of several distant trans-Neptunian objects.
Compton Scattering by the Proton
Galler, G; Kondratev, R; Massone, A M; Wolf, S; Ahrens, J; Arends, H J; Beck, R; Camen, M; Capitani, G P; Grabmayr, P; Hall, S J; Härter, F; Hehl, T; Jennewein, P; Kossert, K; Lvov, A I; Molinari, C; Ottonello, P; Peise, J; Preobrajenskij, I; Proff, S; Robbiano, A; Sanzone, M; Schumacher, M; Schmitz, M; Wissmann, F
2001-01-01
Compton scattering by the proton has been measured over a wide range covering photon energies 250 MeV < E_\\gamma < 800 MeV and photon scattering angles 30^0 < \\theta^{lab}_\\gamma < 150^0, using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The data are in good agreement with the dispersion theory based on the SAID-SM99K parameterization of photo-meson amplitudes. From the subset of data between 280 and 360 MeV the resonance pion-photoproduction amplitudes were evaluated leading to the multipole E2/M1 ratio EMR(340 MeV) =(-1.6 \\pm 0.4(stat+syst) \\pm 0.2(model)%. From all data below 455 MeV the proton's backward spin polarizability was determined to be \\gamma_\\pi=(-37.9 \\pm 0.6(stat+syst) \\pm 3.5(model))x10^{-4}fm^4.
Pion scattering and nuclear dynamics
International Nuclear Information System (INIS)
A phenomenological optical-model analysis of pion elastic scattering and single- and double-charge-exchange scattering to isobaric-analog states is reviewed. Interpretation of the optical-model parameters is briefly discussed, and several applications and extensions are considered. The applications include the study of various nuclear properties, including neutron deformation and surface-fluctuation contributions to the density. One promising extension for the near future would be to develop a microscopic approach based on powerful momentum-space methods brought to existence over the last decade. In this, the lowest-order optical potential as well as specific higher-order pieces would be worked out in terms of microscopic pion-nucleon and delta-nucleon interactions that can be determined within modern meson-theoretical frameworks. A second extension, of a more phenomenological nature, would use coupled-channel methods and shell-model wave functions to study dynamical nuclear correlations in pion double charge exchange. 35 refs., 11 figs., 1 tab
Intrabeam scattering in the LHC
Mertens, Tom; Sousa Da Costa, Miguel
2011-01-01
Intrabeam Scattering (IBS) is the process where particles within an accelerator beam elastically scatter off each other. The effect of IBS is not to be confused with the Coulomb repulsion due to the fields generated by the other particles in the beam. The Coulomb repulsion effects are referred to as space-charge effects in Accelerator Physics and become less important than IBS at high energies because of the 1/gamma^2 that occurs in the space-charge equations making IBS one of the most important causes of beam size growth. At high energies (for example at 7 TeV or the LHC nominal operation energy) IBS effects are counteracted by Radiation Damping effects, in some cases leading to decrease in beam sizes instead of beam growth. But at the time of writing the operation energies were still low enough to neglect Radiation Damping Effects in comparison with IBS effects (Radiation Lifetimes were a factor five to ten higher than the IBS Lifetimes in the cases presented at the end of this text). Because of its effect ...
Scattering amplitudes in gauge theories
International Nuclear Information System (INIS)
First monographical text on this fundamental topic. Course-tested, pedagogical and self-contained exposition. Includes exercises and solutions. At the fundamental level, the interactions of elementary particles are described by quantum gauge field theory. The quantitative implications of these interactions are captured by scattering amplitudes, traditionally computed using Feynman diagrams. In the past decade tremendous progress has been made in our understanding of and computational abilities with regard to scattering amplitudes in gauge theories, going beyond the traditional textbook approach. These advances build upon on-shell methods that focus on the analytic structure of the amplitudes, as well as on their recently discovered hidden symmetries. In fact, when expressed in suitable variables the amplitudes are much simpler than anticipated and hidden patterns emerge. These modern methods are of increasing importance in phenomenological applications arising from the need for high-precision predictions for the experiments carried out at the Large Hadron Collider, as well as in foundational mathematical physics studies on the S-matrix in quantum field theory. Bridging the gap between introductory courses on quantum field theory and state-of-the-art research, these concise yet self-contained and course-tested lecture notes are well-suited for a one-semester graduate level course or as a self-study guide for anyone interested in fundamental aspects of quantum field theory and its applications. The numerous exercises and solutions included will help readers to embrace and apply the material presented in the main text.
Laser scatter in clinical applications
Luther, Ed; Geddie, William
2008-02-01
Brightfield Laser Scanning Imaging (BLSI) is available on Laser Scanning Cytometers (LSCs) from CompuCyte Corporation. Briefly, digitation of photodetector outputs is coordinated with the combined motions of a small diameter (typically 2 to 10 microns) laser beam scanning a specimen in the Y direction (directed by a galvanometer-driven scanning mirror) and the microscope stage motion in the X direction. The output measurements are assembled into a two-dimensional array to provide a "non-real" digital image, where each pixel value reports the amount of laser-scattered light that is obtained when the laser beam is centered on that location. Depending on the detector positions, these images are analogous to Differential Interference Contrast or Phase Contrast microscopy. We report the incorporation of the new laser scattering capabilities into the workflow of a high-volume clinical cytology laboratory at University Health Network, Toronto, Canada. The laboratory has been employing LSC technology since 2003 for immunophenotypic fluorescence analysis of approximately 1200 cytological specimens per year, using the Clatch methodology. The new BLSI component allows visualization of cellular morphology at higher resolution levels than is possible with standard brightfield microscopic evaluation of unstained cells. BLSI is incorporated into the triage phase, where evaluation of unstained samples is combined with fluorescence evaluation to obtain specimen background levels. Technical details of the imaging methodology will be presented, as well as illustrative examples from current studies and comparisons to detailed, but obscure, historical studies of cytology specimens based on phase contrast microscopy.
Light scattering of degenerate fermions
Aubin, S.; Leblanc, L. J.; Myrskog, S.; Extavour, M. H. T.; McKay, D.; Stummer, A.; Thywissen, J. H.
2006-05-01
We report on progress in measuring the suppression of resonant light scattering in a gas of degenerate fermions. A gas of trapped degenerate fermions is expected to exhibit narrower optical linewidths and longer excited state lifetimes than single atoms when the Fermi energy is larger than the photon recoil energy [1-3]. In this case, the number of available states into which a scattered atom can recoil is significantly reduced due to the filling of the Fermi sea. We produce a degenerate gas of 4x10^4 ultra-cold fermionic ^40K atoms by sympathetic cooling with bosonic ^87Rb in a micro-magnetic chip trap. The atoms can then be loaded into a tight dipole trap just above the surface of the chip and probed with a near resonance laser pulse. [1] Th. Busch, J. R. Anglin, J. I. Cirac, and P. Zoller, Europhys. Lett. 44, 1 (1998). [2] B. DeMarco and D. S. Jin, Phys. Rev. A 58, R4267 (1998). [3] J. Javanainen and J. Ruostekosky, Phys. Rev. A 52, 3033 (1995). Work supported by NSERC, CFI, OIT, Research Corporation, and PRO.
Institute of Scientific and Technical Information of China (English)
Lanqing Xu; Hui Li; Yongping Zheng
2009-01-01
Monte Carlo algorithm and Stokes-Mueller formalism are used to simulate the propagation behavior of polarized light in turbid media. The influence of single scattering and multiple scattering on backscattered Mueller matrix in turbid media is discussed. Single and double scattering photons form the major part of backscattered polarization patterns, while multiple scattering photons present more likely as background. Further quantitative analyses show that single scattering approximation and double scattering approxima tion are quite accurate when discussing the polarization patterns near the incident point.
Entanglement degradation in depolarizing light scattering
International Nuclear Information System (INIS)
Full text: In the classical regime, when a beam of light is scattered by a medium, it may emerge partially or completely depolarized depending on the optical properties of the medium. Correspondingly, in the quantum regime, when an entangled two-photon pair is scattered, the classical depolarization may result in an entanglement degradation. Here, relations between photon scattering, entanglement and multi-mode detection are investigated. We establish a general framework in which one- and two-photon elastic scattering processes can be discussed, and we focus on the study of the intrinsic entanglement degradation caused by a multi-mode detection. We show that any multi-mode scattered state cannot maximally violate the Bell-CHSH inequality because of the momentum spread. The results presented here have general validity and can be applied to both deterministic and random scattering processes. (author)
An improved algorithm for cloud multiple scattering
Institute of Scientific and Technical Information of China (English)
Guibin Yuan; Xiaogang Sun; Jingmin Dai
2006-01-01
@@ Clouds' radiation characteristics are very important in clouds scene simulation, weather forecasting, pattern recognition, and other fields. Radiation of a cloud mainly comes from its multiple scattering. A new algorithm to calculate multiple scattering, called build-up factor algorithm, is proposed in this paper. In this algorithm, a modified gamma distribution is assumed to describe droplets distribution inside a cloud, then the radiation transport equation is calculated to get the solution of single scattering, and finally, a build-up factor is defined to estimate the multiple scattering contributions. This algorithm considers both single scattered radiance and multiple scattered radiance and needs shorter computing time. It can be used in real time simulations.
Improved Scatter Search Using Cuckoo Search
Directory of Open Access Journals (Sweden)
Ahmed T.Sadiq Al-Obaidi
2013-02-01
Full Text Available The Scatter Search (SS is a deterministic strategy that has been applied successfully to some combinatorial and continuous optimization problems. Cuckoo Search (CS is heuristic search algorithm which is inspired by the reproduction strategy of cuckoos. This paper presents enhanced scatter search algorithm using CS algorithm. The improvement provides Scatter Search with random exploration for search space of problem and more of diversity and intensification for promising solutions. The original and improved Scatter Search has been tested on Traveling Salesman Problem. A computational experiment with benchmark instances is reported. The results demonstrate that the improved Scatter Search algorithms produce better performance than original Scatter Search algorithm. The improvement in the value of average fitness is 23.2% comparing with original SS. The developed algorithm has been compared with other algorithms for the same problem, and the result was competitive with some algorithm and insufficient with another.
Multichannel forward scattering meter for oceanography
Mccluney, W. R.
1974-01-01
An instrument was designed and built that measures the light scattered at several angles in the forward direction simultaneously. The instrument relies on an optical multiplexing technique for frequency encoding of the different channels suitable for detection by a single photodetector. A Mie theory computer program was used to calculate the theoretical volume scattering function for a suspension of polystyrene latex spheres. The agreement between the theoretical and experimental volume scattering functions is taken as a verification of the calibration technique used.
Lectures on the inverse scattering method
International Nuclear Information System (INIS)
In a series of six lectures an elementary introduction to the theory of inverse scattering is given. The first four lectures contain a detailed theory of solitons in the framework of the KdV equation, together with the inverse scattering theory of the one-dimensional Schroedinger equation. In the fifth lecture the dressing method is described, while the sixth lecture gives a brief review of the equations soluble by the inverse scattering method. (author)
Kaons and antiproton-nucleus scattering
Haque, S; Rahman, S N
2003-01-01
The elastic scattering of Kaons and antiprotons from several nuclei is studied in the framework of the generalized diffraction model due to Frahn and Venter. The systematics of reaction cross section and the standard nuclear radius, as given by the model, are discussed. The parameters obtained from the elastic scattering analyses are used, without any adjustment, to reproduce some inelastic scattering angular distributions and the corresponding deformation parameters are determined.
Light scattering from dislocations in silicon
Monier, Vanessa; Capello, Luciana; Kononchuk, Oleg; Pichaud, Bernard
2010-11-01
Nondecorated glide dislocations in Czochralski grown silicon have been studied by laser scattering tomography technique. Dependence of intensity of scattered light on polarization of the incident light has been measured for different orientations of the dislocation line and Burgers vector. Detailed theory of light scattering by dislocation in silicon crystals is presented. It is shown that by combination of polarization and tomography measurements it is possible to determine slip system of nondecorated mixed dislocation in Si.
Aharonov-Bohm scattering on a cone
Alvarez, Marcos
1998-01-01
The Aharonov-Bohm scattering amplitude is calculated in the context of planar gravity with localized sources which also carry a magnetic flux. These sources cause space-time to develop conical singularities at their location, thus introducing novel effects in the scattering of electrically charged particles. The behaviour of the wave function in the proximity of the classical scattering directions is analyzed by means of an asymptotic expansion previously introduced by the author. It is found...
Scattering properties of PT-symmetric objects
Miri, Mohammad-Ali; Facao, Margarida; Abouraddy, Ayman F; Bakry, Ahmed; Razvi, Mir A N; Alshahrie, Ahmed; Alù, Andrea; Christodoulides, Demetrios N
2016-01-01
We investigate the scattering response of parity-time (PT) symmetric structures. We show that, due to the local flow of energy between gain and loss regions, such systems can deflect light in unusual ways, as a function of the gain/loss contrast. Such structures are highly anisotropic and their scattering patterns can drastically change as a function of the angle of incidence. In addition, we derive a modified optical theorem for PT-symmetric scattering systems, and discuss its ramifications.
Analysis of light transport in scattering media
Mukaigawa, Yasuhiro; Yagi, Yasushi; Raskar, Ramesh
2010-01-01
We propose a new method to analyze light transport in homogeneous scattering media. The incident light undergoes multiple bounces in translucent objects, and produces a complex light field. Our method analyzes the light transport in two steps. First, single and multiple scattering are separated by projecting high-frequency stripe patterns. Then, multiple scattering is decomposed into each bounce component based on the light transport equation. The light field for each bounce is recursively es...
Boundary scattering in the phi^4 model
Dorey, Patrick; Mercer, James; Romanczukiewicz, Tomasz; Shnir, Yasha
2015-01-01
We study boundary scattering in the phi^4 model on a half-line with a one-parameter family of Neumann-type boundary conditions. A rich variety of phenomena is observed, which extends previously-studied behaviour on the full line to include regimes of near-elastic scattering, the restoration of a missing scattering window, and the creation of a kink or oscillon through the collision-induced decay of a metastable boundary state.
High-precision positioning of radar scatterers
Dheenathayalan, P.; Small, D; Schubert, A.; Hanssen, R.F.
2016-01-01
Remote sensing radar satellites cover wide areas and provide spatially dense measurements, with millions of scatterers. Knowledge of the precise position of each radar scatterer is essential to identify the corresponding object and interpret the estimated deformation. The absolute position accuracy of synthetic aperture radar (SAR) scatterers in a 2D radar coordinate system, after compensating for atmosphere and tidal effects, is in the order of centimeters for TerraSAR-X (TSX) spotlight imag...
Inelastic scattering of neutrons by superconducting rings
Agafonov, A. I.
2010-01-01
The differential cross section for the inelastic magnetic scattering of neutrons by superconducting rings is derived theoretically taking account of the interaction of the neutron magnetic moment with magnetic field created by the superconducting current. In this scattering process the neutron kinetic energy increases discretely and, respectively, the number of the magnetic flux quanta trapped in the ring, reduces. Quantitative calculations of the scattering cross section for cold neutrons is...
Energy Transfer in Scattering by Rotating Potentials
Indian Academy of Sciences (India)
Volker Enss; Vadim Kostrykin; Robert Schrader
2002-02-01
Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave operators, and existence of a conserved quantity under scattering. In a simple model we determine the energy transferred to a particle by collision with a rotating blade.
Fingerprint Recognition Using Translation Invariant Scattering Network
Minaee, Shervin; Wang, Yao
2015-01-01
Fingerprint recognition has drawn a lot of attention during last decades. Different features and algorithms have been used for fingerprint recognition in the past. In this paper, a powerful image representation called scattering transform/network, is used for recognition. Scattering network is a convolutional network where its architecture and filters are predefined wavelet transforms. The first layer of scattering representation is similar to sift descriptors and the higher layers capture hi...
Learning-based imaging through scattering media.
Horisaki, Ryoichi; Takagi, Ryosuke; Tanida, Jun
2016-06-27
We present a machine-learning-based method for single-shot imaging through scattering media. The inverse scattering process was calculated based on a nonlinear regression algorithm by learning a number of training object-speckle pairs. In the experimental demonstration, multilayer phase objects between scattering plates were reconstructed from intensity measurements. Our approach enables model-free sensing, where it is not necessary to know the sensing processes/models. PMID:27410537
Eye model with controllable lens scattering
Paeglis, R; Ozolinsh, M; Cikmacs, P; Andersson-Engels, Stefan
2001-01-01
A model of human eye for experiments in vision research has been developed using PLZT ceramics. This ``artificial eye{''} allows to simulate light scattering caused by cataract in the eye lens. Light scattering of a composite eye lens of the model depends on the electric field applied to a transparent electrooptic PLZT ceramics plate that is attached directly to the lens. The image degradation in such a model eye at various degrees of scattering is studied observing and recording the ...
On the scattering power of radiotherapy protons
Gottschalk, Bernard
2009-01-01
Scattering power (T = d/dx of mean squared multiple Coulomb scattering (MCS) angle), as used in proton transport theory, is properly viewed as a differential description of the Gaussian approximation to MCS theories such as Moliere's. That is, we seek a function T which, when integrated over a finite slab, will recover the Moliere/Fano/Hanson angle for that slab. To be accurate, T must include a single scattering correction, which means mathematically it must be nonlocal, depending on how muc...
Quantum rainbow scattering at tunable velocities
Strebel, M; Ruff, B; Stienkemeier, F; Mudrich, M
2012-01-01
Elastic scattering cross sections are measured for lithium atoms colliding with rare gas atoms and SF6 molecules at tunable relative velocities down to ~50 m/s. Our scattering apparatus combines a velocity-tunable molecular beam with a magneto-optic trap that provides an ultracold cloud of lithium atoms as a scattering target. Comparison with theory reveals the quantum nature of the collision dynamics in the studied regime, including both rainbows as well as orbiting resonances.
Instruments and accessories for neutron scattering research
International Nuclear Information System (INIS)
This report describes neutron scattering instruments and accessories installed by four neutron scattering research groups at the ASRC (Advanced Science Research Center) of the JAERI and the recent topics of neutron scattering research using these instruments. The specifications of nine instruments (HRPD, BIX-I, TAS-1 and PNO in the reactor hall, RESA, BIX-II, TAS-2, LTAS and SANS-J in the guide hall of the JRR-3M) are summarized in this booklet. (author)
The Scattering Approach to the Casimir Force
Reynaud, S.; Canaguier-Durand, A.; Messina, R; Lambrecht, A.; Neto, P A Maia
2010-01-01
We present the scattering approach which is nowadays the best tool for describing the Casimir force in realistic experimental configurations. After reminders on the simple geometries of 1d space and specular scatterers in 3d space, we discuss the case of stationary arbitrarily shaped mirrors in electromagnetic vacuum. We then review specific calculations based on the scattering approach, dealing for example with the forces or torques between nanostructured surfaces and with the force between ...
Forward-peaked scattering of polarized light.
Clark, Julia P; Kim, Arnold D
2014-11-15
Polarized light propagation in a multiple scattering medium is governed by the vector radiative transfer equation. We analyze the vector radiative transfer equation in asymptotic limit of forward-peaked scattering and derive an approximate system of equations for the Stokes parameters, which we call the vector Fokker-Planck approximation. The vector Fokker-Planck approximation provides valuable insight into several outstanding issues regarding the forward-peaked scattering of polarized light such as the polarization memory phenomenon. PMID:25490484
Kaons and antiproton-nucleus scattering
International Nuclear Information System (INIS)
The elastic scattering of Kaons and antiprotons from several nuclei is studied in the framework of the generalized diffraction model due to Frahn and Venter. The systematics of reaction cross section and the standard nuclear radius, as given by the model, are discussed. The parameters obtained from the elastic scattering analyses are used, without any adjustment, to reproduce some inelastic scattering angular distributions and the corresponding deformation parameters are determined. (author)
An approximate method for classical scattering problems
International Nuclear Information System (INIS)
An approximate method of calculating scattering cross sections is presented. Newton's second law and the conservation of energy are used to relate the scattering angle to the impulse delivered to the projectile by the scatterer. In order to calculate the impulse, it is necessary to know the time dependence of the trajectory. We assume that the projectile travels the two asymptotes to the actual trajectory with constant velocity
Inelastic Neutron Scattering from Cerium under Pressure
DEFF Research Database (Denmark)
Rainford, B. D.; Buras, B.; Lebech, Bente
1977-01-01
Inelastic neutron scattering from Ce metal at 300 K was studied both below and above the first order γ-α phase transition, using a triple axis spectrometer. It was found that (a) there is no indication of any residual magnetic scattering in the collapsed α phase, and (b) the energy width of the...... paramagnetic scattering in the γ-phase increases with pressure. We conclude that Jsf increases with pressure, as has been predicted byCoqblin....
summation ++p scattering experiment at KEK
International Nuclear Information System (INIS)
The new low energy hyperon-nucleon scattering data have been long waited since the low statistics data were obtained in 1960s from the bubble chamber experiments. At KEK, an experiment to measure summation ++p elastic scattering has been performed utilizing the novel scintillating fiber technology. In this report we present the status of the analysis on this experiment and the preliminary total cross section data of summation ++p scattering
Circular Intensity Differential Scattering of chiral molecules
Energy Technology Data Exchange (ETDEWEB)
Bustamante, C.J.
1980-12-01
In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.
Improved Scatter Search Using Cuckoo Search
Ahmed T.Sadiq Al-Obaidi
2013-01-01
The Scatter Search (SS) is a deterministic strategy that has been applied successfully to some combinatorial and continuous optimization problems. Cuckoo Search (CS) is heuristic search algorithm which is inspired by the reproduction strategy of cuckoos. This paper presents enhanced scatter search algorithm using CS algorithm. The improvement provides Scatter Search with random exploration for search space of problem and more of diversity and intensification for promising solutions. The origi...
Bistatic Forward Scattering Radar Detection and Imaging
Hu Cheng; Liu Changjiang; Zeng Tao
2016-01-01
Forward Scattering Radar (FSR) is a special type of bistatic radar that can implement image detection, imaging, and identification using the forward scattering signals provided by the moving targets that cross the baseline between the transmitter and receiver. Because the forward scattering effect has a vital significance in increasing the targets’ Radar Cross Section (RCS), FSR is quite advantageous for use in counter stealth detection. This paper first introduces the front line technology u...
Dynamic light scattering optical coherence tomography
Lee, Jonghwan; Wu, Weicheng; Jiang, James Y.; Zhu, Bo; Boas, David A.
2012-01-01
We introduce an integration of dynamic light scattering (DLS) and optical coherence tomography (OCT) for high-resolution 3D imaging of heterogeneous diffusion and flow. DLS analyzes fluctuations in light scattered by particles to measure diffusion or flow of the particles, and OCT uses coherence gating to collect light only scattered from a small volume for high-resolution structural imaging. Therefore, the integration of DLS and OCT enables high-resolution 3D imaging of diffusion and flow. W...
Hierarchy in chaotic scattering in Hill's problem
Kovács, Z
1997-01-01
Hierarchic properties of chaotic scattering in a model of satellite encounters, studied first by Petit and Henon, are examined by decomposing the dwell time function and comparing scattering trajectories. The analysis reveals an (approximate) ternary organization in the chaotic set of bounded orbits and the presence of a stable island. The results can open the way for a calculation of global quantities characterizing the scattering process by using tools of the thermodynamic formalism.
Report on Workshop on Geometric Scattering
DEFF Research Database (Denmark)
As part of the activities of MaPhySto a workshop on geometric scattering was organized at University of Aarhus, November 5-7, 1998. The workshop was narrowly focused on geometric scattering, and in particular the use of geometric scattering in understanding the structure of the scattering operator...... for the quantum mechanical many-body problem. A number of other questions were also discussed in detail, including the resonances and various geometric questions. This report includes the program of the workshop, a collection of previews, abstracts, and reports on the lectures, with extensive...
Applications of neutron scattering in materials science
International Nuclear Information System (INIS)
It can be expected that the application of neutron scattering in materials science will become more widespread with increasing interaction between neutron scatterers and materials scientists. Several potential growth areas are identified, e.g., structural analysis of polycrystalline and multi-phase systems as well as amorphous substances; small-angle scattering analysis of extended defects such as vacancy clusters, precipitate zones, etc., including the kinetics of their formation, in crystalline and vitreous substances; and dynamic effects near phase transformations. Small-angle scattering methods are illustrated by two examples, the formation of voids in β'-NiAl and the decomposition of Al-Zn alloys. (author)
Neutron scattering studies of diffusion in solids
International Nuclear Information System (INIS)
This chapter shows how the scattering of slow neutrons can be used to learn about the microscopic mechanisms of atomic diffusion in solids. It discusses properties of the neutron; scattering experiments and spectrometers; types of diffusion studies; the neutron scattering cross-section; coherent and incoherent scattering; scattering functions and Van Hove correlation functions; interpretation of correlation functions in the classical approximation; long-time limit and elastic scattering; self-correlation and incoherent scattering functions for specific models; separation of different motions; continuous translational and rotational diffusion; diffusion by discrete jumps; explicit calculation of the incoherent scattering function for local atomic jump diffusion between two sites; three examples of local jump diffusion; diffusion on a lattice; fast ion diffusion in solid electrolytes; and phenomenological treatment of coherent quasielastic scattering. Advantages of the neutron method are that it does not require a macroscopic concentration gradient (the diffusion process can therefore be studied in homogeneous systems at equilibrium and with well-defined concentrations of mobile atoms); it is non-destructive (neutron measurements of diffusion can be carried out on a single sample); and neutron experiments can be performed under extreme conditions of temperature and pressure
Scattering equations and global duality of residues
Søgaard, Mads; Zhang, Yang
2016-05-01
We examine the polynomial form of the scattering equations by means of computational algebraic geometry. The scattering equations are the backbone of the Cachazo-He-Yuan (CHY) representation of the S-matrix. We explain how the Bezoutian matrix facilitates the calculation of amplitudes in the CHY formalism, without explicitly solving the scattering equations or summing over the individual residues. Since for n -particle scattering the size of the Bezoutian matrix grows only as (n -3 )×(n -3 ), our algorithm is very efficient for analytic and numeric amplitude computations.
Hadron scattering and resonances in QCD
Dudek, Jozef J.
2016-05-01
I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study ππ elastic scattering, including the ρ resonance, as well as coupled-channel π >K, ηK scattering. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.
Hadron scattering and resonances in QCD
Energy Technology Data Exchange (ETDEWEB)
Dudek, Jozef J. [Old Dominion Univ., Norfolk, VA (United States)
2016-05-01
I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study pi pi elastic scattering, including the rho resonance, as well as coupled-channel pi K, eta K scattering. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.
Scatter corrections for cone beam optical CT
Energy Technology Data Exchange (ETDEWEB)
Olding, Tim; Holmes, Oliver [Department of Physics, Queen' s University (United Kingdom); Schreiner, L John [Medical Physics Department, Cancer Centre of Southeastern Ontario (Canada)], E-mail: Tim.Olding@krcc.on.ca
2009-05-01
Cone beam optical computed tomography (OptCT) employing the VISTA scanner (Modus Medical, London, ON) has been shown to have significant promise for fast, three dimensional imaging of polymer gel dosimeters. One distinct challenge with this approach arises from the combination of the cone beam geometry, a diffuse light source, and the scattering polymer gel media, which all contribute scatter signal that perturbs the accuracy of the scanner. Beam stop array (BSA), beam pass array (BPA) and anti-scatter polarizer correction methodologies have been employed to remove scatter signal from OptCT data. These approaches are investigated through the use of well-characterized phantom scattering solutions and irradiated polymer gel dosimeters. BSA corrected scatter solutions show good agreement in attenuation coefficient with the optically absorbing dye solutions, with considerable reduction of scatter-induced cupping artifact at high scattering concentrations. The application of BSA scatter corrections to a polymer gel dosimeter lead to an overall improvement in the number of pixel satisfying the (3%, 3mm) gamma value criteria from 7.8% to 0.15%.
Experimental observation of nonlinear Thomson scattering
Chen, Szu-yuan; Maksimchuk, Anatoly; Umstadter, Donald
1998-01-01
A century ago, J. J. Thomson showed that the scattering of low-intensity light by electrons was a linear process (i.e., the scattered light frequency was identical to that of the incident light) and that light's magnetic field played no role. Today, with the recent invention of ultra-high-peak-power lasers it is now possible to create a sufficient photon density to study Thomson scattering in the relativistic regime. With increasing light intensity, electrons quiver during the scattering proc...
Multiple scattering in optical coherence microscopy.
Yadlowsky, M J; Schmitt, J M; Bonner, R F
1995-09-01
We show that the multiple-scatter rejection provided by optical coherence microscopy (low-coherence interferometry) can be incomplete in optically turbid media and that multiple scattering manifests itself in two distinct ways. Multiple small-angle scattering results in an effective probe field that is stronger than expected from a first-order beam extinction model, but that contains a distorted wave front that enhances the apparent reflectance of small structures relative to those that are larger than the unscattered incident beam. Multiple wide-angle scattering produces a broad diffuse haze that reduces the contrast of subsequent features. PMID:21060400
Theory of Light Scattering in Axion Electrodynamics
Ochiai, Tetsuyuki
2012-09-01
Taking account of the axion term in the Maxwell Lagrangian, we present a rigorous theory of light scattering in piecewise-constant axion fields. In particular, we focus on axionic substances with confined and/or curved geometries, and the scattering matrices of an axionic slab, cylinder, and sphere are derived analytically. The axion term generates a surface current with off-diagonal optical conductivity, giving rise to a new type of photospin--orbit interaction. As a result, various novel light-scattering phenomena can take place. We demonstrate enhanced Faraday rotation, parity-violating light scattering, and strong perturbation of dipole radiation.
Forward Scattering of Loaded and Unloaded Antennas
DEFF Research Database (Denmark)
Gustafsson, Mats; Andersen, Jørgen Bach; Kristensson, Gerhard;
2012-01-01
Forward scattering of antennas is related to antenna performance via the forward-scattering sum rule. The forward-scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizability of the...... antenna structure. Here, the forward-scattering sum rule is experimentally verified for loaded, short-circuit, and open-circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas with a...
Recent developments in high-frequency scattering
International Nuclear Information System (INIS)
Recent applications of the complex angular momentum theory of Mie scattering are reviewed: (i) very accurate asymptotic expansions for the average Mie cross sections for extinction, absorption and radiation pressure, averaged over a small range of size dispersion, have been obtained; (ii) forward optical glory effects have been predicted; (iii) A new diffraction effect, critical scattering, that takes place in the transition region around the critical scattering angle, has been treated, yielding results in good agreement with the exact Mie values. An overview of the major diffraction effects found in Mie scattering is also given. (Author)
Temperature Dependent Neutron Scattering Sections for Polyethylene
Hill, Roger E.; Liu, C. -Y.
2003-01-01
This note presents neutron scattering cross sections for polyethylene at 296 K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The polyethylene density of states (from 0 to sub eV) adopted to derive the new kernel is presented. We compare our calculated room temperature total scattering cross sections and doubl...
Scattering by two spheres: Theory and experiment
DEFF Research Database (Denmark)
Bjørnø, Irina; Jensen, Leif Bjørnø
1998-01-01
three issues: (1) to develop a simplified theory for scattering by two elastical spheres; (2) to measure the scattering by two spheres in a water tank, and (3) to compare the theoretical/numerical results with the measured data. A number of factors influencing multiple scattering, including the......Extensive studies of scattering of acoustical signals by targets of different regular shapes have formed a useful background for attempts to develop procedures for remote monitoring of suspended materials in marine environments as, for instance, measurements of characteristic parameters of...
Multiple magnetic scattering in small-angle neutron scattering of Nd–Fe–B nanocrystalline magnet
Ueno, Tetsuro; Saito, Kotaro; Yano, Masao; Ito, Masaaki; Shoji, Tetsuya; Sakuma, Noritsugu; Kato, Akira; Manabe, Akira; Hashimoto, Ai; Gilbert, Elliot P.; Keiderling, Uwe; Ono, Kanta
2016-01-01
We have investigated the influence of multiple scattering on the magnetic small-angle neutron scattering (SANS) from a Nd–Fe–B nanocrystalline magnet. We performed sample-thickness- and neutron-wavelength-dependent SANS measurements, and observed the scattering vector dependence of the multiple magnetic scattering. It is revealed that significant multiple scattering exists in the magnetic scattering rather than the nuclear scattering of Nd–Fe–B nanocrystalline magnet. It is considered that the mean free path of the neutrons for magnetic scattering is rather short in Nd–Fe–B magnets. We analysed the SANS data by the phenomenological magnetic correlation model considering the magnetic microstructures and obtained the microstructural parameters. PMID:27321149
New techniques in neutron scattering
International Nuclear Information System (INIS)
New neutron sources being planned, such as the Advanced Neutron Source (ANS) or the European Spallation Source (ESS), will provide an order of magnitude flux increase over what is available today, but neutron scattering will still remain a signal-limited technique. At the same time, the development of new materials, such as polymer and ceramic composites or a variety of complex fluids, will increasingly require neutron-based research. This paper will discuss some of the new techniques which will allow us to make better use of the available neutrons, either through improved instrumentation or through sample manipulation. Discussion will center primarily on unpolarized neutron techniques since polarized neutrons will be the subject of the next paper. (author)
Topics in elementary scattering theory
International Nuclear Information System (INIS)
In these lectures a summary is given of some of the fundamental ideas and formalism used to describe and understand the interactions of elementary particles. A brief review of relativistic kinematics is followed by a discussion of Lorentz-invariant variables for describing two-body processes, phase space and plots, such as the Dalitz plot, which can be used to study some aspects of the dynamics of an interaction, relatively free from kinematic complications. A general description of scattering and decay is given and then, more specifically, some aspects of two-body interactions in the absence of spin are discussed. Finally, complications that arise when particle spin has to be taken into account are considered. (U.K.)
Neutron scattering in polymer physics
Richter, D.
2000-03-01
By example this short review presents recent scientific advances which were achieved by the application of neutron scattering to polymer systems, thereby, keeping in mind also practical applications. We first focus on experiments on the structure and morphology of polymer systems covering conformational studies, investigations on polymer-microemulsions systems and the observation of aggregation states in living polymerization. Thereafter, we present recent results in the field of polymer dynamics. We begin with local motions which are behind the classical relaxation processes in polymer melts. Then we relate to universal dynamics, we address the Rouse model and its limits, present new results on the dynamic miscibility in blends and display the latest investigations on entanglement dynamics. Finally, we report first observations of ripplon excitations of phase boundaries in diblock copolymer melts.
Grassmannian geometry of scattering amplitudes
Arkani-Hamed, Nima; Cachazo, Freddy; Goncharov, Alexander; Postnikov, Alexander; Trnka, Jaroslav
2016-01-01
Outlining a revolutionary reformulation of the foundations of perturbative quantum field theory, this book is a self-contained and authoritative analysis of the application of this new formulation to the case of planar, maximally supersymmetric Yang–Mills theory. The book begins by deriving connections between scattering amplitudes and Grassmannian geometry from first principles before introducing novel physical and mathematical ideas in a systematic manner accessible to both physicists and mathematicians. The principle players in this process are on-shell functions which are closely related to certain sub-strata of Grassmannian manifolds called positroids - in terms of which the classification of on-shell functions and their relations becomes combinatorially manifest. This is an essential introduction to the geometry and combinatorics of the positroid stratification of the Grassmannian and an ideal text for advanced students and researchers working in the areas of field theory, high energy physics, and the...
Neutron scattering and models : molybdenum.
Energy Technology Data Exchange (ETDEWEB)
Smith, A.B.
1999-05-26
A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of {le} 30 MeV is given. New experimental elemental-scattering information over the incident energy range 4.5 {r_arrow} 10 MeV is presented. Spherical, vibrational and dispersive models are deduced and discussed, including isospin, energy-dependent and mass effects. The vibrational models are consistent with the ''Lane potential''. The importance of dispersion effects is noted. Dichotomies that exist in the literature are removed. The models are vehicles for fundamental physical investigations and for the provision of data for applied purposes. A ''regional'' molybdenum model is proposed. Finally, recommendations for future work are made.
Polymer research by neutron scattering
International Nuclear Information System (INIS)
Polymer physics aims on an understanding of the macroscopic behavior of polymer systems on the basis of their molecular structure and dynamics. For this purpose neutrons serve as a unique probe, allowing a simultaneous investigation of polymer structure and dynamics on a molecular scale. Furthermore, hydrogen deuterium exchange facilitates molecular labeling and offers the possibility to observe selected chains or chain parts in dense systems. Neutron small angle scattering reveals information on the conformation and possible aggregation of polymer chains. Data on linear and star like molecules are shown as examples. High resolution neutron spin-echospectroscopy observes the molecular dynamics of long chain molecules. Results on the large scale motion of chins in polymer melts are presented. finally, experiments on chain relaxation close to the glass transition are displayed. Three distinctly different relaxation processes are revealed. (author)
International Nuclear Information System (INIS)
Cross sections for elastic and inelastic scattering of electrons from 17O have been measured for momentum transfers up to 1.2 fm-1. The elastic cross section indicates that the rms charge radii of 17O and 16O are equal to within a few parts in a thousand: 217>sup(1/2)/216>sub(1/2)=1.0015+-0.0025. Reduced transition probabilities and ground-state radiative widths are deduced for 17O excited states below 9 MeV. Various aspects of the inelastic spectrum are discussed, with emphasis on the 'single-particle' levels at 0.871 (1/2+) and 5.083 (3/2+) MeV, the levels at 7.569 (7/2-) and 7.378 (5/2+) MeV, and the spectrum of electric octupole excitations. (Auth.)
Scattering theory for Riemannian Laplacians
DEFF Research Database (Denmark)
Ito, Kenichi; Skibsted, Erik
condition is certain bounds of derivatives up to order one of the trace of this quantity. These conditions are shown to be optimal for existence and completeness of a wave operator. Our theory does not involve prescribed asymptotic behaviour of the metric at infinity (like asymptotic Euclidean or hyperbolic......In this paper we introduce a notion of scattering theory for the Laplace-Beltrami operator on non-compact, connected and complete Riemannian manifolds. A principal condition is given by a certain positive lower bound of the second fundamental form of angular submanifolds at infinity. Another...... metrics studied previously in the literature). A consequence of the theory is spectral theory for the Laplace-Beltrami operator including identification of the continuous spectrum and absence of singular continuous spectrum....
Neutron scattering and models: molybdenum
International Nuclear Information System (INIS)
A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of le 30 MeV is given. New experimental elemental-scattering information over the incident energy range 4.5 rarrow 10 MeV is presented. Spherical, vibrational and dispersive models are deduced and discussed, including isospin, energy-dependent and mass effects. The vibrational models are consistent with the ''Lane potential''. The importance of dispersion effects is noted. Dichotomies that exist in the literature are removed. The models are vehicles for fundamental physical investigations and for the provision of data for applied purposes. A ''regional'' molybdenum model is proposed. Finally, recommendations for future work are made
Reactive scattering of halogen molecules
International Nuclear Information System (INIS)
A study of the endoergic, bimolecular reactions of F2 with I2, ICl, and HI in a crossed molecular beam experiment is described. The trihalogens IIF, ClIF, and HIF were directly observed as the products of these reactions. At high collision energies a second reactive channel producing IF becomes important. Product angular and velocity distributions show that this IF does not result from a four-center exchange reaction. Measured threshold energies for the formation of IIF, ClIF, and HIF yield lower bounds to the stabilities of these molecules, with respect to the separated atoms, of 69, 81, and 96 kcal/mole, respectively. Analysis of product center-of-mass angular distributions indicates that a slightly nonlinear approach is most effective in bringing about reaction to form the stable triatomic radical. Also described is a crossed molecular beam study of the Cl + Br2 → BrCl + Br reaction at collision energies from 6.8 to 17.7 kcal/mole. The results indicate that this reaction has the characteristics of an exoergic reaction on an attractive potential energy surface with early energy release. Reagent translational energy is very efficiently channeled into product internal energy. At high collision energy the reaction appears to approach the spectator stripping limit. Finally, a series of computer programs which can be used to carry out the requisite data analysis for crossed molecular beam reactive scattering experiments are described. These programs recover the reactive scattering center-of-mass flux distribution from the measured angular and velocity distributions of the products
International Nuclear Information System (INIS)
We construct discrete space-time coordinates separated by the Lorentz-invariant intervals h/mc in space and h/mc2 in time using discrimination (XOR) between pairs of independently generated bit-strings; we prove that if this space is homogeneous and isotropic, it can have only 1, 2 or 3 spacial dimensions once we have related time to a global ordering operator. On this space we construct exact combinatorial expressions for free particle wave functions taking proper account of the interference between indistinguishable alternative paths created by the construction. Because the end-points of the paths are fixed, they specify completed processes; our wave functions are ''born collapsed''. A convenient way to represent this model is in terms of complex amplitudes whose squares give the probability for a particular set of observable processes to be completed. For distances much greater than h/mc and times much greater than h/mc2 our wave functions can be approximated by solutions of the free particle Dirac and Klein-Gordon equations. Using a eight-counter paradigm we relate this construction to scattering experiments involving four distinguishable particles, and indicate how this can be used to calculate electromagnetic and weak scattering processes. We derive a non-perturbative formula relating relativistic bound and resonant state energies to mass ratios and coupling constants, equivalent to our earlier derivation of the Bohr relativistic formula for hydrogen. Using the Fermi-Yang model of the pion as a relativistic bound state containing a nucleon-antinucleon pair, we find that (GπN2)2 = (2mN/mπ)2 - 1. 21 refs., 1 fig
Elastic Pion Scattering on the Deuteron in a Multiple Scattering Model
Kamalov, S. S.; Tiator, L.; Bennhold, C.
1996-01-01
Pion elastic scattering on deuterium is studied in the KMT multiple scattering approach developed in momentum space. Using a Paris wave function and the same methods and approximations as commonly used in pion scattering on heavier nuclei excellent agreement with differential cross section data is obtained for a wide range of pion energies. Only for $T_{\\pi}>250$ MeV and very backward angles, discrepancies appear that are reminiscent of disagreements in pion scattering on $^3$He, $^3$H, and $...
International Nuclear Information System (INIS)
We have measured the surface scattering efficiency of a new ceramic composite, based on boron carbide, that was recently proposed for use as a shielding material for pulsed neutron scattering instrumentation. The results show that, due to a relevant presence of clay material in the composite, the surface scattering efficiency is higher than other common shielding materials, which are used on pulsed neutron scattering instrumentation, and suggest revising the material composition.
Absolute calibration of small angle neutron scattering data using strong coherent scattering
Lee, D.; Barker, J; Chen, S.
1993-01-01
Typically, small angle neutron scattering (SANS) data is normalized to an absolute scale using secondary standards such as water, polymers, silica gels, or irradiated aluminum. Errors for this method of calibration arise when the initial determination or calculation of the standard's scattering cross-section is no longer valid due to degradation or wavelength-dependent multiple scattering or detector efficiency effects. Here we illustrate how strong coherent scattering can be used to experime...
Systematic study on nuclear resonant scattering
International Nuclear Information System (INIS)
New resonant scattering effect of thermal neutron capture gamma rays from Ti and Fe on Sb, Cu, Se and Ce target were observed. These results together with those published by other authors are summarized and discussed in terms of a possible systematic search for new resonant scattering effects
Scattering of high energy electrons on deuteron
International Nuclear Information System (INIS)
The aim of this work is to obtain information on the neutron form factor from the study of the scattering of electrons on deuterium. The first part is dedicated to the theoretical study of the elastic and inelastic scattering. We introduce different form factors: Sachs form factor, the Pauli and Dirac form factors, they appear in the analytic expression of the scattering cross-section. We show how the deuteron form factors can be deduced from neutron's and proton's form factors. In the case of the inelastic scattering we show how the cross section can be broken into components associated to partial waves and we obtain different formulas for the inelastic cross-section based on the Breit formula or the Durand formalism. The second part is dedicated to the experiment setting of electron scattering on deuterium. The elastic scattering experiment has been made on solid or liquid CD2 targets while inelastic scattering has been studied on a liquid target. We have used an electron beam produced by the Orsay linear accelerator and the scattered electrons have been analysed by a magnetic spectrometer and a Cerenkov detector. The results give a very low value (slightly positive)for the charge form factor of the neutron and a magnetic form factor for the neutron slightly below that of the proton
Small Angle Light Scattering by Biological Objects
International Nuclear Information System (INIS)
In this paper the small angle laser radiation scattering by the particles of different shape and size is analyzed. Experimental results and theoretical calculations show that after ejection from bacteriophage DNA forms the scattering medium consisted of quasi-spherical elements with radius of R⁓10λ0. (author)
Critical Magnetic Scattering of Neutrons in Iron
DEFF Research Database (Denmark)
Passell, L.; Blinowski, K.; Brun, T.;
1965-01-01
Measurements of the angular and energy distributions of 4.28 Å neutrons scattered at small angles from iron at temperatures above the Curie temperature are described. The results are interpreted in terms of Van Hove's theory of critical magnetic scattering and yield information on the range of spin...
On high energy scattering inside gravitational backgrounds
Nastase, Horatiu
2004-01-01
We analyze the high energy scattering inside gravitational backgrounds using 't Hooft's formalism. The scattering is equivalent to geodesic shifts accross Aichelburg-Sexl waves inside the gravitational backgrounds. We find solutions for A-S waves inside various backgrounds and analyze them.
Correlation effects in multiple hard scattering
International Nuclear Information System (INIS)
Correlations between the incoming partons in multiple hard scattering can affect both the event rate and kinematic distributions in the final state. In this talk, I discuss different types of correlations relevant for double parton scattering in proton-proton collisions.
Scattering Amplitudes via Algebraic Geometry Methods
DEFF Research Database (Denmark)
Søgaard, Mads
Feynman diagrams. The study of multiloop scattering amplitudes is crucial for the new era of precision phenomenology at the Large Hadron Collider (LHC) at CERN. Loop-level scattering amplitudes can be reduced to a basis of linearly independent integrals whose coefficients are extracted from generalized...
Radio wave scattering in the outer heliosphere
Cairns, Iver H.
1995-01-01
Current models for the 2-3 kHz emissions observed by the Voyager spacecraft in the outer heliosphere involve 2f(p) radiation generated near the termination shock or the heliopause. Radio wave scattering by solar wind density irregularities strongly affects observed sources of f(p) and 2f(p) emission in the inner heliosphere and the characteristics of astrophysical sources. In particular, the angular size, brightness temperature, and time variability of the source are strongly affected by scattering, thereby having major implications for the inferred size, energy budget, time variability, location, and nature of the source if scattering is ignored. This paper addresses whether scattering is important for interpreting the Voyager 2-3 kHz emissions. Quantitative calculations (with and without diffraction) are performed for the angular broadening of an outer heliospheric source as a function of path length, radiation frequency relative to f(p) and the spectrum of density irregularities. The effects of scattering in both the solar wind and the heliosheath are considered. Predictions for radial gradients in the source's apparent angular size and in the source's modulation index are presented. The calculations are compared with observations and the results discussed. First estimates suggest that scattering plausibly dominates the observed source size. The observed trend in modulation index with heliocentric distance is consistent with scattering being important and the source being in the outer heliosphere. Additional arguments for scattering being important are summarized.
An Algebraic Approach to the Scattering Equations
Huang, Rijun; Rao, Junjie; Feng, Bo; He, Yang-Hui
2015-01-01
We employ the so-called companion matrix method from computational algebraic geometry, tailored for zero-dimensional ideals, to study the scattering equations. The method renders the CHY-integrand of scattering amplitudes computable using simple linear algebra and is amenable to an algorithmic approach. Certain identities in the amplitudes as well as rationality of the final integrand become immediate in this formalism.
Multiple Scattering of Quantum Optical States
DEFF Research Database (Denmark)
Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter
2011-01-01
Wave propagation through multiple scattering media has been an active research field since the discovery of Anderson localization [1]. This interest has amongst other resulted in the discovery of classical wave phenomena such as enhanced coherent back scattering [2] and universal conductance...
Blue Skies, Coffee Creamer, and Rayleigh Scattering
Liebl, Michael
2010-01-01
The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…
Collective spectral properties of Raman scattering
International Nuclear Information System (INIS)
The theory of collective Raman scattering has been developed by using the quantum-mechanical master-equation approach and secular approximation. The influence of the frequency detuning of resonance and other parameters on the collective spectral properties of scattered light is investigated
High-precision positioning of radar scatterers
Dheenathayalan, P.; Small, D.; Schubert, A.; Hanssen, R.F.
2016-01-01
Remote sensing radar satellites cover wide areas and provide spatially dense measurements, with millions of scatterers. Knowledge of the precise position of each radar scatterer is essential to identify the corresponding object and interpret the estimated deformation. The absolute position accuracy
Correlation effects in multiple hard scattering
Diehl, Markus
2013-01-01
Correlations between the incoming partons in multiple hard scattering can affect both the event rate and kinematic distributions in the final state. In this talk, I discuss different types of correlations relevant for double parton scattering in proton-proton collisions.
Delta excitations in neutrino-nucleus scattering
Kim, H; Horowitz, C J; Kim, Hungchong
1995-01-01
We derive the contribution of \\Delta-h excitations to quasielastic charged-current neutrino-nucleus scattering in the framework of relativistic mean-field theory. We discuss the effect of \\Delta production on the determination of the axial mass M_A in neutrino scattering experiments.
Elastic and nuclear Raman scattering of photons
International Nuclear Information System (INIS)
Some recent experimental studies of fundamental photon scattering processes and inelastic scattering performed at the Negev IRR-2 reactor in the E 166Er and 238U in the approx. 15 MeV region, performed at the University of Illinois are discussed. (orig.) 891 KBE/orig. 892 ARA
Heavy ion elastic scattering of code : OPTHI
International Nuclear Information System (INIS)
A computer code, OPTHI has been designed to calculate nuclear optical model elastic cross sections for the scattering of heavy ions. The program has been designed to be utilitarian rather than capable of giving an exact description of elastic scattering. Input format is described and the program listing is given. (M.G.B.)
Inverse acoustic problem of N homogeneous scatterers
DEFF Research Database (Denmark)
Berntsen, Svend
The three-dimensional inverse acoustic medium problem of N homogeneous objects with known geometry and location is considered. It is proven that one scattering experiment is sufficient for the unique determination of the complex wavenumbers of the objects. The mapping from the scattered fields at a...
Mie scattering near the critical angle
International Nuclear Information System (INIS)
Complex angular momentum theory is applied to the problem of high-frequency critical light scattering by a spherical cavity near the critical angle. The main contributions to the scattering arise from a critical domain close to critical incidence. The results are in good agreement with the exact Mie solution. (author)
Scattering theory of dynamic electrical transport
Buttiker, Markus; Moskalets, Mykhaylo
2006-01-01
We have developed a scattering matrix approach to coherent transport through an adiabatically driven conductor based on photon-assisted processes. To describe the energy exchange with the pumping fields we expand the Floquet scattering matrix up to linear order in driving frequency.
Inverse scattering problem in turbulent magnetic fluctuations
Treumann, R A; Narita, Y
2016-01-01
We apply a particular form of the inverse scattering theory to turbulent magnetic fluctuations in a plasma. In the present note we develop the theory, formulate the magnetic fluctuation problem in terms of its electrodynamic turbulent response function, and reduce it to the solution of a special form of the famous Gel$'$fand-Levitan-Marchenko equation of quantum mechanical scattering theory.
Compton scattering and the complementarity principle
International Nuclear Information System (INIS)
We explain briefly why Compton scattering from a crystal gives a featureless continuous x-ray background while Bragg scattering from the same crystal produces sharp diffraction peaks. It is shown that the answer lies at the heart of quantum mechanics, namely the uncertainty and the complementarity principles. (author)
Overview: Electromagnetic Scattering from Ocean Surface
Institute of Scientific and Technical Information of China (English)
ZHAO Zhi-qin
2006-01-01
Understanding the sea surface scattering process is very important in the development of models to detect the target above or under the surface. In this paper, both the analytical and the numerical methods applied in sea surface scattering are summarized. Some important problems concerned in this field are discussed. For numerical study, edge effect brings artificial nonrealistic scattering and therefore must be suppressed. Different edge treatment methods are compared in this paper. Scattering of breaking wave surface at very low grazing angle always needs more attentions than other scattering problems. Some numerical results show the existence of the special phenomena at very low grazing angle, for example, the "sea spikes" and the Doppler splitting.
Decoherence due to elastic Rayleigh scattering
Uys, H; VanDevender, A P; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, J J
2010-01-01
We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off-resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering \\textit{amplitudes} for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic scattering \\textit{rates} from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of $^9$Be$^+$ in a 4.5 T magnetic field.
Decoherence due to Elastic Rayleigh Scattering
Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Meiser, D.; Ozeri, R.; Bollinger, J. J.
2010-11-01
We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of Be+9 in a 4.5 T magnetic field.
Quantum correction of photon-scattering errors
Akerman, Nitzan; Glickman, Yinnon; Ozeri, Roee
2011-01-01
Quantum decoherence is one of the main obstacles for realizing large-scale quantum information processing. Spontaneous photon scattering is a notable example of such environment induced error and is a fundamental limit to the fidelity of quantum operations. In the scattering process the qubit loses its distinctive and coherent character owing to the entanglement of the qubit with the photon. However, by utilizing the information carried by the photon we are able to coherently reverse this process and correct for the scattering error. Using a single trapped ion, we implement this quantum correction protocol in real-time with a fidelity greater than 85%. We further use quantum process tomography to characterize spontaneous scattering errors and their correction protocol. The error mechanism investigated here, will enable future quantum error-correction, that requires less knowledge on the scattered photon, thus negating a fundamental limit to quantum operations on atomic superpositions
Modelling the inelastic scattering of fast electrons
Energy Technology Data Exchange (ETDEWEB)
Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); D' Alfonso, A.J., E-mail: a.j@dalfonso.com.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia)
2015-04-15
Imaging at atomic resolution based on the inelastic scattering of electrons has become firmly established in the last three decades. Harald Rose pioneered much of the early theoretical work on this topic, in particular emphasising the role of phase and the importance of a mixed dynamic form factor. In this paper we review how the modelling of inelastic scattering has subsequently developed and how numerical implementation has been achieved. A software package μSTEM is introduced, capable of simulating various imaging modes based on inelastic scattering in both scanning and conventional transmission electron microscopy. - Highlights: • Harald Rose was a pioneer of important work on atomic resolution imaging using inelastic scattering. • We review how the modelling of inelastic scattering has subsequently developed and been applied. • A software package μSTEM is introduced, capable of simulating various inelastic imaging modes.
Incoherent neutron scattering by solid hydrogen
International Nuclear Information System (INIS)
An account is given of experiments investigating the movements of molecule concentrations and the whary motion in solid hydrogen by means of incoherent neutron scattering. A first comparison with theoretical data shows that there is a high amount of multiple scattering in the measured signals. Therefore, an existing Monte-Carlo programme has been extended so as to enable a comprehensive simulation of the experiment to be done with a given scattering function, thus allowing very exact corrections to be carried out for multiple scattering. With the aid of this programme it is shown that the experimental data relating to the movements of the molecule concentrations can be very well described by a scattering function which shows formal identity with that describing a harmonic crystal. (orig./HPOE)
Modelling the inelastic scattering of fast electrons
International Nuclear Information System (INIS)
Imaging at atomic resolution based on the inelastic scattering of electrons has become firmly established in the last three decades. Harald Rose pioneered much of the early theoretical work on this topic, in particular emphasising the role of phase and the importance of a mixed dynamic form factor. In this paper we review how the modelling of inelastic scattering has subsequently developed and how numerical implementation has been achieved. A software package μSTEM is introduced, capable of simulating various imaging modes based on inelastic scattering in both scanning and conventional transmission electron microscopy. - Highlights: • Harald Rose was a pioneer of important work on atomic resolution imaging using inelastic scattering. • We review how the modelling of inelastic scattering has subsequently developed and been applied. • A software package μSTEM is introduced, capable of simulating various inelastic imaging modes
Scattering of fast neutrons from elemental molybdenum
International Nuclear Information System (INIS)
Differential broad-resolution neutron-scattering cross sections of elemental molybdenum were measured at 10 to 20 scattering angles distributed between 20 and 160 degrees and at incident-neutron energy intervals of approx. = 50 to 200 keV from 1.5 to 4.0 MeV. Elastically-scattered neutrons were fully resolved from inelastic events. Lumped-level inelastic-neutron-scattering cross sections were determined corresponding to observed excitation energies of; 789 +- 23, 195 +- 23, 1500 +- 34, 1617 +- 12, 1787, 1874, 1991, 2063 +- 24, 2296, 2569 and 2802 keV. An optical-statistical model was deduced from the measured elastic-scattering results. The experimental values were compared with the respective quantities given in ENDF/B-V
Controlling electromagnetic scattering with wire metamaterial resonators
Filonov, Dmitry S; Iorsh, Ivan; Belov, Pavel A; Ginzburg, Pavel
2016-01-01
Manipulation of radiation is required for enabling a span of electromagnetic applications. Since properties of antennas and scatterers are very sensitive to a surrounding environment, macroscopic artificially created materials are good candidates for shaping their characteristics. In particular, metamaterials enable controlling both dispersion and density of electromagnetic states, available for scattering from an object. As the result, properly designed electromagnetic environment could govern waves' phenomena. Here electromagnetic properties of scattering dipoles, situated inside a wire medium (metamaterial) are analyzed both numerically and experimentally. Impact of the metamaterial geometry, dipole arrangement inside the medium, and frequency of the incident radiation on scattering phenomena was studied. It was shown that the resonance of the dipole hybridizes with Fabry-Perot modes of the metamaterial, giving rise to a complete reshaping of electromagnetic properties. Regimes of controlled scattering sup...
Quasielastic Neutron Scattering by Superionic Strontium Chloride
DEFF Research Database (Denmark)
Dickens, M. H.; Hutchings, M. T.; Kjems, Jørgen;
1978-01-01
The scattering, from powder and single crystal samples, appears only above the superionic transition temperature, 1000K. The integrated intensity is found to be strongly dependent on the direction and magnitude of the scattering vector, Q, (which suggests the scattering is coherent) but does not...... exhibit the periodicity of the reciprocal lattice. The energy width of 0.6-1.5 MeV (FWHM) is found to be only weakly dependent on Q, and almost independent of temperature, suggesting that the scattering is more complex than a direct result of the translational motion of the anions. A direct connection...... with the degree of disorder of the system and the intensity of the scattering is indicated...
On the microscopic foundation of scattering theory
International Nuclear Information System (INIS)
The aim of the thesis is to give a contribution to the microscopic foundation of scattering theory, i. e. to show, how the asymptotic formalism of scattering theory with objects like the S-matrix as well the initial and final asymptotics ψin and ψout can be derived from a microscopic description of the basic system. First the final statistics from a N-particle system through farly distant surfaces is derived. Thereafter we confine us to the 1-particle scattering and apply the final statistics in order to derive the scattering cross section from a microscopical description of the scattering situation. The basing dynamics are Bohm's mechanics, a theory on the motion of point particles, which reproduces all results of nonrelativistic quantum mechanics
Polarized Scattering and Biosignatures in Exoplanetary Atmospheres
Berdyugina, S V
2016-01-01
Polarized scattering in planetary atmospheres is computed in the context of exoplanets. The problem of polarized radiative transfer is solved for a general case of absorption and scattering, while Rayleigh and Mie polarized scattering are considered as most relevant examples. We show that (1) relative contributions of single and multiple scattering depend on the stellar irradiation and opacities in the planetary atmosphere; (2) cloud (particle) physical parameters can be deduced from the wavelength-dependent measurements of the continuum polarization and from a differential analysis of molecular band absorption; (3) polarized scattering in molecular bands increases the reliability of their detections in exoplanets; (4) photosynthetic life can be detected on other planets in visible polarized spectra with high sensitivity. These examples demonstrate the power of spectropolarimetry for exoplanetary research and for searching for life in the universe.
Investigating Static and Dynamic Light Scattering
Sun, Yong
2011-01-01
A new size, static radii $R_{s}$, can be measured accurately using Static Light Scattering (SLS) technique when the Rayleigh-Gans-Debye approximation is valid for dilute homogenous spherical particles in dispersion. The method proposed in this work not only can measures the particle size distribution and average molar mass accurately but also enables us to explore Dynamic Light Scattering (DLS) technique further. Detailed investigation of the normalized time auto-correlation function of the scattered light intensity $g^{2)}(\\tau)$ shows that the measurements of DLS can be expected accurately and the static and hydrodynamic radii of nanoparticles are different. Only at some special conditions, the Z-average hydrodynamic radius can be measured accurately at a given scattering angle. The fact that the values of average hydrodynamic radius measured at different scattering angles are consistent or the values of polydispersity index are small does not mean the particle size distribution is narrow or monodisperse.
Temperature Dependent Neutron Scattering Sections for Polyethylene
Hill, R E; Hill, Roger E.
2003-01-01
This note presents neutron scattering cross sections for polyethylene at 296 K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The polyethylene density of states (from 0 to sub eV) adopted to derive the new kernel is presented. We compare our calculated room temperature total scattering cross sections and double differential cross sections at 232 meV at various angles with the available experimental data (at room temperature), and then extrapolate the calculations to lower temperatures (77K and 4K). The new temperature dependent scattering kernel gives a good quantitative fit to the available room temperature data and has a temperature dependence that is qualitatively consistent with thermodynamics.
Radiofrequency encoded angular-resolved light scattering
DEFF Research Database (Denmark)
Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.;
2015-01-01
The sensitive, specific, and label-free classification of microscopic cells and organisms is one of the outstanding problems in biology. Today, instruments such as the flow cytometer use a combination of light scatter measurements at two distinct angles to infer the size and internal complexity...... of cells at rates of more than 10,000 per second. However, by examining the entire angular light scattering spectrum it is possible to classify cells with higher resolution and specificity. Current approaches to performing these angular spectrum measurements all have significant throughput limitations...... Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...
Translation correlations in anisotropically scattering media
Judkewitz, Benjamin; Horstmeyer, Roarke; Vellekoop, Ivo M.; Papadopoulos, Ioannis N.; Yang, Changhuei
2015-08-01
Controlling light propagation across scattering media by wavefront shaping holds great promise for a wide range of communications and imaging applications. But, finding the right shape for the wavefront is a challenge when the mapping between input and output scattered wavefronts (that is, the transmission matrix) is not known. Correlations in transmission matrices, especially the so-called memory effect, have been exploited to address this limitation. However, the traditional memory effect applies to thin scattering layers at a distance from the target, which precludes its use within thick scattering media, such as fog and biological tissue. Here, we theoretically predict and experimentally verify new transmission matrix correlations within thick anisotropically scattering media, with important implications for biomedical imaging and adaptive optics.
Stochastic Methods for Zero Energy Quantum Scattering
Koch, J H; Lenz, S; Koch, Justus H.; Mall, Hubertus R.; Lenz, Stefan
1997-01-01
We investigate the use of stochastic methods for zero energy quantum scattering based on a path integral approach. With the application to the scattering of a projectile from a nuclear many body target in mind, we use the potential scattering of a particle as a test for the accuracy and efficiency of several methods. To be able to deal with complex potentials, we introduce a path sampling action and a modified scattering observable. The approaches considered are the random walk, where the points of a path are sequentially generated, and the Langevin algorithm, which updates an entire path. Several improvements are investigated. A cluster algorithm for dealing with scattering problems is finally proposed, which shows the best accuracy and stability.
Comparative evaluation of scatter correction in 3D PET using different scatter-level approximations
International Nuclear Information System (INIS)
In 3D positron emission tomography (PET), scatter of the gamma photons is one of the most significant physical factors which degrades not only image quality but also quantification. The currently most used scatter estimation method is the analytic single scatter simulation (SSS) which usually accommodates for multiple scattering by scaling the single scatter estimation. However, it has not been clear yet how accurate this approximation is for cases where multiple scatter is significant, raising the question: 'How important is correction for multiple scattered photons, and how accurately do we need to simulate all scattered events by appropriate scaling?' This study answers these questions and evaluates the accuracy of SSS implementation in the open-source library software for tomographic image reconstruction (STIR). Different scatter orders approximations are evaluated including different levels of scattering and different scaling approaches using Monte Carlo (id est (i.e.) Sim system for emission tomography (SET)) data. SimSET simulations of a large anthropomorphic phantom were reconstructed with iterative reconstruction algorithms. Images reconstructed with 3D filtered back-projection reprojection algorithm have been compared quantitatively in order to clarify the errors due to different scatter order approximations. Quantification in regions has improved by scatter correction. For example, in the heart the ideal value was 3, whereas before scatter correction the standard uptake value (SUV) was 4.0, after single scatter correction was 3.3 and after single and double scatter correction was 3.0. After correction by scaling single scatter with tail-fit, the SUV was 3.1, whereas with total-fit it was 3.0. Similarly, for the SSS correction methodology implemented in STIR using tail-fit the heart SUV was 3.1 whereas using total-fit it was 3.0. The results demonstrate that correction for double scatter improves image contrast and therefore it is required for the
Neutron Scattering for battery materials
International Nuclear Information System (INIS)
Batteries are a key technology in today’s society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Since the “lithium-ion” configuration has been widely accepted, significant efforts have been devoted to attain high energy and power densities to produce an excellent energy storage system without any safety issues. To improve battery characteristics, deep insights into the structure of the materials during the battery reactions are necessary. Neutron Scatteringclarifies a wide range of structures for battery materials; from local to long range structures, and these structure characteristics are related to the battery properties. New materials with high electrochemical properties are necessary to improve future battery systems. Structure and property relationships for the battery electrodes and electrolytes are important information for designing new energy storage systems. An example of new materials is solid electrolytes. An all solid-state configuration is the most promising for future devices to improve the reliability of batteries. Lithium superionic conductors, which can be used as solid electrolytes, promise the potential to replace organic liquid electrolytes and thereby improve the safety of batteries. The material, Li10GeP2S12 shows high ionic conductivity, which exceeds the conductivity value of liquid electrolyte. Neutron Scatteringis one of the best methods to provide information of structure containing lithium and conduction mechanism determined by Neutron Scattering makes the materials design concept clear. In-situ and perando experimental techniques are another important subjects for clarifying battery reactions. An in situ technique for directly observing surface structural changes has been developed that employs thin-film model electrodes and surface X-ray and Neutron Scattering techniques. The surface structural changes commence with the formation of an electrical double layer
A light-scattering study of the scattering matrix elements of Arizona Road Dust
International Nuclear Information System (INIS)
We report measurements of the light scattering matrix elements of Arizona Road Dust, which has irregular shapes. Our experimental apparatus used photodiode arrays to detect scattered light simultaneously at many angles including small angles that are necessary for accurate characterization of large particles. The setup was calibrated with single slit diffraction and water droplet scattering. Guinier analysis yielded the dust particle size. Q-space analysis of the dust scattering yielded a comprehensive description of scattering in terms of power laws with quantifiable exponents. - Highlights: • The scattering apparatus detects light at 31 angles, 0.3–157°, simultaneously. • Three sizes of Arizona Road Dust are studied. • Guinier analysis characterizes the radii of gyration of the dusts. • Q-space analysis of dust scattered intensity reveals power laws with exponents
Neutron Scattering and Elastic Constants
International Nuclear Information System (INIS)
Elastic constants of crystals obtained from neutron scattering techniques at frequencies, ω, of the order of 1012 cps, are frequently compared with those obtained with ultrasonic techniques for which ω 10 cps. If the normal modes of vibration of the crystal did not interact with each other or with other excitations in the crystal, these elastic constants would be identical. In a real crystal, however, interactions exist, and these lead to different behaviour, depending on whether the elastic wave propagates in a collision-free, ωτ >> 1, mode or a collision-dominated ωτ 3 have demonstrated this difference. In piezoelectric crystals τ is related to the time required for the electric polarization to follow the elastic wave. At frequencies so high that the electric polarization cannot follow the elastic wave, experiments on DKDP have shown that the elastic constants do not exhibit the anormaly present at low frequencies. Similar behaviour is expected to occur near many phase transitions which show anomalous elastic behaviour. Analogous, but probably smaller, effects occur through the interactions of elastic waves with conduction electrons in metals and with the spins in magnetic materials. (author)
Parity violation in electron scattering
International Nuclear Information System (INIS)
The elaboration of the electroweak standard model from the discovery of parity violation to the weak neutral current is described in the first chapter. In the second chapter the author discusses the 2 experimental approaches of the parity violation experiments. In the first approach the weak neutral current can be assumed to be well known and can be used as a probe for the hadronic matter. The second approach consists in measuring the weak neutral current between 2 particles with known internal structure in order to test the predictions of the standard model in the low energy range. The chapters 3 and 4 are an illustration of the first approach through the HAPPEx series of experiments that took place in the Jefferson Laboratory from 1998 to 2005. The HAPPEx experiments aimed at measuring the contribution of strange quarks in the electromagnetic form factors of the nucleon through the violation of parity in the elastic scattering at forward angles. The last chapter is dedicated to the E158 experiment that was performed at the Slac (California) between 2000 and 2003. The weak neutral current was measured between 2 electrons and the high accuracy obtained allowed the physics beyond the standard model to be indirectly constraint up to a few TeV. (A.C.)
SCATTERING POLARIZATION IN SOLAR FLARES
International Nuclear Information System (INIS)
There is ongoing debate about the origin and even the very existence of a high degree of linear polarization of some chromospheric spectral lines observed in solar flares. The standard explanation of these measurements is in terms of the impact polarization caused by non-thermal proton and/or electron beams. In this work, we study the possible role of resonance line polarization due to radiation anisotropy in the inhomogeneous medium of the flare ribbons. We consider a simple two-dimensional model of the flaring chromosphere and we self-consistently solve the non-LTE problem taking into account the role of resonant scattering polarization and of the Hanle effect. Our calculations show that the horizontal plasma inhomogeneities at the boundary of the flare ribbons can lead to a significant radiation anisotropy in the line formation region and, consequently, to a fractional linear polarization of the emergent radiation of the order of several percent. Neglecting the effects of impact polarization, our model can provide a clue for resolving some of the common observational findings, namely: (1) why a high degree of polarization appears mainly at the edges of the flare ribbons; (2) why polarization can also be observed during the gradual phase of a flare; and (3) why polarization is mostly radial or tangential. We conclude that radiation transfer in realistic multi-dimensional models of solar flares needs to be considered as an essential ingredient for understanding the observed spectral line polarization
Exclusive scattering off the deuteron
International Nuclear Information System (INIS)
Exclusive processes are a special class of processes giving insight into the inner structure of hadrons. In this thesis we consider two exclusive processes and compute their total cross sections as well as the beam charge and beam polarization asymmetries for different kinematical constraints. These calculations o er the opportunity to get access to the nonperturbative GPDs. Theoretically they can be described with the help of models. The rst process we investigate contains a GPD of the pion, which is basically unknown so far. We include different models and make predictions for observables that could in principle be measured at HERMES at DESY and CLAS at JLab. The second process we consider is electron-deuteron scattering in the kinematical range where the deuteron breaks up into a proton and a neutron. This can be used to investigate the neutron, which cannot be taken as a target due to its lifetime of approximately 15 minutes. For the calculation of the electron-deuteron cross section we implement models for the proton and neutron GPDs. Once there are experimental data available our calculations are ready for comparison. (orig.)
Exclusive scattering off the deuteron
Energy Technology Data Exchange (ETDEWEB)
Amrath, D.
2007-12-15
Exclusive processes are a special class of processes giving insight into the inner structure of hadrons. In this thesis we consider two exclusive processes and compute their total cross sections as well as the beam charge and beam polarization asymmetries for different kinematical constraints. These calculations o er the opportunity to get access to the nonperturbative GPDs. Theoretically they can be described with the help of models. The rst process we investigate contains a GPD of the pion, which is basically unknown so far. We include different models and make predictions for observables that could in principle be measured at HERMES at DESY and CLAS at JLab. The second process we consider is electron-deuteron scattering in the kinematical range where the deuteron breaks up into a proton and a neutron. This can be used to investigate the neutron, which cannot be taken as a target due to its lifetime of approximately 15 minutes. For the calculation of the electron-deuteron cross section we implement models for the proton and neutron GPDs. Once there are experimental data available our calculations are ready for comparison. (orig.)
Single scatter electron Monte Carlo
Energy Technology Data Exchange (ETDEWEB)
Svatos, M.M. [Lawrence Livermore National Lab., CA (United States)|Wisconsin Univ., Madison, WI (United States)
1997-03-01
A single scatter electron Monte Carlo code (SSMC), CREEP, has been written which bridges the gap between existing transport methods and modeling real physical processes. CREEP simulates ionization, elastic and bremsstrahlung events individually. Excitation events are treated with an excitation-only stopping power. The detailed nature of these simulations allows for calculation of backscatter and transmission coefficients, backscattered energy spectra, stopping powers, energy deposits, depth dose, and a variety of other associated quantities. Although computationally intense, the code relies on relatively few mathematical assumptions, unlike other charged particle Monte Carlo methods such as the commonly-used condensed history method. CREEP relies on sampling the Lawrence Livermore Evaluated Electron Data Library (EEDL) which has data for all elements with an atomic number between 1 and 100, over an energy range from approximately several eV (or the binding energy of the material) to 100 GeV. Compounds and mixtures may also be used by combining the appropriate element data via Bragg additivity.
SCATTERING POLARIZATION IN SOLAR FLARES
Energy Technology Data Exchange (ETDEWEB)
Štěpán, Jiří; Heinzel, Petr [Astronomical Institute ASCR, Fričova 298, 251 65 Ondřejov (Czech Republic)
2013-11-20
There is ongoing debate about the origin and even the very existence of a high degree of linear polarization of some chromospheric spectral lines observed in solar flares. The standard explanation of these measurements is in terms of the impact polarization caused by non-thermal proton and/or electron beams. In this work, we study the possible role of resonance line polarization due to radiation anisotropy in the inhomogeneous medium of the flare ribbons. We consider a simple two-dimensional model of the flaring chromosphere and we self-consistently solve the non-LTE problem taking into account the role of resonant scattering polarization and of the Hanle effect. Our calculations show that the horizontal plasma inhomogeneities at the boundary of the flare ribbons can lead to a significant radiation anisotropy in the line formation region and, consequently, to a fractional linear polarization of the emergent radiation of the order of several percent. Neglecting the effects of impact polarization, our model can provide a clue for resolving some of the common observational findings, namely: (1) why a high degree of polarization appears mainly at the edges of the flare ribbons; (2) why polarization can also be observed during the gradual phase of a flare; and (3) why polarization is mostly radial or tangential. We conclude that radiation transfer in realistic multi-dimensional models of solar flares needs to be considered as an essential ingredient for understanding the observed spectral line polarization.
Electronic Raman Scattering in Graphene
Institute of Scientific and Technical Information of China (English)
LU Hong-Yan; WANG Qiang-Hua
2008-01-01
Linear dispersion near the Dirac points in the band structure of graphenes can give rise to novel physical properties.We calculate the electronic contribution to the Raman spectra in graphenes, which also shows novel features.In the clean limit, the Raman spectrum in the undoped graphene is linear (with a universal slope against impurity scattering) at low energy due to the linear dispersion near the Dirac points, and it peaks at a position corresponding to the van Hove singularity in the band structure. In a doped graphene, the electronic Raman absorption is forbidden up to a vertical inter-band particle-hole gap. Beyond the gap the spectrum follows the undoped case. In the presence of impurities, absorption within the gap (in the otherwise clean case) is induced, which is identified as the intra-band contribution. The Drude-like intra-band contribution is seen to be comparable to the higher energy inter-band Raman peak. The results are discussed in connection to experiments.
Hydrodynamic instabilities and neutron scattering
International Nuclear Information System (INIS)
The flow pattern in a liquid layer heated from below changes character as the vertical temperature gradient is increased. A review is given for the sequence of instabilities connected with the different flow regimes, with emphasis on their phase-transition aspects. Utilizing the coupling that exists between the molecular orientation and flow in a liquid crystal, we have used neutron scattering to explore these phenomena. The special features of liquid crystals in this respect are pointed out. Experiments near the lowest lying instability, the Rayleigh-Benard transition, verify the mean-field predictions for the change of the threshold gradient with the applied magnetic field, the behaviour of the order parameter (the fluid velocity) versus epsilon (the reduced gradient scale), the time-dependent growth and the critical slowing down of the growth rate of the order parameter. A pre-transitional tail of intensity is analysed within the same formalism and it is suggested that it arises from hydrodynamic fluctuations driven by the microscopic fluctuations of the liquid. Experiments at higher gradients reveal a time-periodic flow regime with frequencies down to cycles per hour. These observations lend support to modern theories for the transition to turbulence. (author)
"Phonon" scattering beyond perturbation theory
Qiu, WuJie; Ke, XueZhi; Xi, LiLi; Wu, LiHua; Yang, Jiong; Zhang, WenQing
2016-02-01
Searching and designing materials with intrinsically low lattice thermal conductivity (LTC) have attracted extensive consideration in thermoelectrics and thermal management community. The concept of part-crystalline part-liquid state, or even part-crystalline part-amorphous state, has recently been proposed to describe the exotic structure of materials with chemical- bond hierarchy, in which a set of atoms is weakly bonded to the rest species while the other sublattices retain relatively strong rigidity. The whole system inherently manifests the coexistence of rigid crystalline sublattices and fluctuating noncrystalline substructures. Representative materials in the unusual state can be classified into two categories, i.e., caged and non-caged ones. LTCs in both systems deviate from the traditional T -1 relationship ( T, the absolute temperature), which can hardly be described by small-parameter-based perturbation approaches. Beyond the classical perturbation theory, an extra rattling-like scattering should be considered to interpret the liquid-like and sublattice-amorphization-induced heat transport. Such a kind of compounds could be promising high-performance thermoelectric materials, due to the extremely low LTCs. Other physical properties for these part-crystalline substances should also exhibit certain novelty and deserve further exploration.
Multiple scattering processes: inverse and direct
International Nuclear Information System (INIS)
The purpose of the work is to formulate inverse problems in radiative transfer, to introduce the functions b and h as parameters of internal intensity in homogeneous slabs, and to derive initial value problems to replace the more traditional boundary value problems and integral equations of multiple scattering with high computational efficiency. The discussion covers multiple scattering processes in a one-dimensional medium; isotropic scattering in homogeneous slabs illuminated by parallel rays of radiation; the theory of functions b and h in homogeneous slabs illuminated by isotropic sources of radiation either at the top or at the bottom; inverse and direct problems of multiple scattering in slabs including internal sources; multiple scattering in inhomogeneous media, with particular reference to inverse problems for estimation of layers and total thickness of inhomogeneous slabs and to multiple scattering problems with Lambert's law and specular reflectors underlying slabs; and anisotropic scattering with reduction of the number of relevant arguments through axially symmetric fields and expansion in Legendre functions. Gaussian quadrature data for a seven point formula, a FORTRAN program for computing the functions b and h, and tables of these functions supplement the text
The art of specifying optics for scatter
Stover, John C.
2006-08-01
Light scatter is a bothersome source of noise in many optical systems. As one example, this is particularly true for telescopes and weapons systems where imaging, tracking and identifying relatively weak signals in the presence of much stronger light sources is critical. As a general rule optical components are not specified for scatter. Instead, almost across the optics industry roughness specifications are routinely (and inadequately) substituted. Issues include: misuse (or ignoring) spatial frequency bandwidths for roughness specifications, using one dimensional roughness statistics for two dimensional applications, ignoring profilometer high frequency roll off (where a lot of scatter is generated) and ignoring the effects surface coatings have on scatter. As an example most roughness measurements extend only to spatial frequencies of about 0.1 μm -1, which corresponds to visible scatter only about five degrees from the reflected specular beam. Scatter into the rest of the hemisphere is ignored. The problems are not easy. Measuring every optic for scatter at the wavelengths of use, for example, is not a reasonable solution. This paper reviews the relevant technical issues and indicates a cost effective solution that will drop optical noise floors if implemented by both government contractors and their vendors.
Attosecond neutron scattering from open quantum systems
Energy Technology Data Exchange (ETDEWEB)
Dreismann, C.; Aris, C. [Institute of Chemistry, Technical University of Berlin (Germany)
2010-07-01
Neutron Compton scattering (NCS) from single nuclei of atoms in molecules, e.g. H{sub 2} (and/or single atoms, e.g. He) is effectuated in the attosecond timescale. The related scattering time is considered in detail, in relation with the Uncertainty Relations. It is shown that the entity scattering time gives a statistical measure of the length of the time interval during which an elementary neutron-nucleus collision may occur, in the same way that the spatial extent of a particle wavefunction (or wavepacket) gives a statistical measure of the extent of the region in which the particle may be found. Consequently, the elementary neutron-nucleus scattering process represents a time-interference phenomenon over the sub-femtosecond ''scattering time'' window. Moreover, the very short-range strong interaction of the neutron-nucleus collision implies that the scattering system (e.g. a proton partically dressed'' with electrons) must be considered as an open quantum system. Experimental results from H{sub 2}, D{sub 2} and HD are mentioned and their anomalous scattering property in the attosecond timescale is qualitatively discussed, also in connection with the Schulman-Gaveau effect.
Light scattering by aggregated red blood cells
Tsinopoulos, Stephanos V.; Sellountos, Euripides J.; Polyzos, Demosthenes
2002-03-01
In low flow rates, red blood cells (RBCs) fasten together along their axis of symmetry and form a so-called rouleaux. The scattering of He-Ne laser light by a rouleau consisting of n (2 less-than-or-equal n less-than-or-equal 8) average-sized RBCs is investigated. The interaction problem is treated numerically by means of an advanced axisymmetric boundary element--fast Fourier transform methodology. The scattering problem of one RBC was solved first, and the results showed that the influence of the RBC's membrane on the scattering patterns is negligible. Thus the rouleau is modeled as an axisymmetric, homogeneous, low-contrast dielectric cylinder, on the surface of which appears, owing to aggregated RBCs, a periodic roughness along the direction of symmetry. The direction of the incident laser light is considered to be perpendicular to the scatterer's axis of symmetry. The differential scattering cross sections in both perpendicular and parallel scattering planes and for all the scattering angles are calculated and presented in detail.
Proceedings of the workshop on neutron scattering instrumentation for SNQ
International Nuclear Information System (INIS)
These proceedings contain the articles presented at the named workshop. These concern instrumentation for neutron diffraction with special regards to small angle scattering, diffuse scattering, inelastic scattering, high resolution spectroscopy, and special techniques. (HSI)
Theory of Multiple Coulomb Scattering from Extended Nuclei
Cooper, L. N.; Rainwater, J.
1954-08-01
Two independent methods are described for calculating the multiple scattering distribution for projected angle scattering resulting when very high energy charged particles traverse a thick scatterer. The results are compared with the theories of Moliere and Olbert.
Neutron Scattering from 36Ar and 4He Films
DEFF Research Database (Denmark)
Carneiro, K.
1977-01-01
Scale factors for neutron diffraction and neutron inelastic scattering are presented for common adsorbates, and the feasibility of experiments is discussed together with the information gained by each type of experiment. Diffraction, coherent inelastic scattering, and incoherent scattering are...
Experiments on n-p scattering with 260-Mev neutrons
Energy Technology Data Exchange (ETDEWEB)
Kelley, E.; Segre, E.; Leith, C.; Wiegand, C.
1950-03-06
Neutrons produced by 350 Mev protons impinging on beryllium are scattered by hydrogen. The authors measure the differential scattering cross section as a function of the scattering angle. Results are summarized here.
EXPERIMENTS ON N-P SCATTERING WITH 260 MEV NEUTRONS
Energy Technology Data Exchange (ETDEWEB)
Kelly, E.; Leith, C.; Segre, E.; Wiegand, C.
1950-03-06
Neutrons produced by 350 Mev protons impinging on beryllium are scattered by hydrogen. We measure the differential scattering cross section as a function of the scattering angle. Results are summarized in Fig. 3 of the paper.
Multi-static synthetic aperture radar and inverse scattering
Gustafsson, Mats
2004-01-01
In this paper synthetic aperture radar is analyzed from an inverse scattering perspective. It is shown that the classical point scattering model can be generalized to a dipole scattering model. The dipole scattering model reduces to the point scattering model for small aperture angles. For large aperture angles or multiple illumination apertures the dipole model gives an anisotropic reﬂectivity such that orthogonal scattering processes are separated. Moreover, it is shown th...
Neutron scattering studies of modulated magnetic structures
Energy Technology Data Exchange (ETDEWEB)
Aagaard Soerensen, Steen
1999-08-01
This report describes investigations of the magnetic systems DyFe{sub 4}Al{sub 8} and MnSi by neutron scattering and in the former case also by X-ray magnetic resonant scattering. The report is divided into three parts: An introduction to the technique of neutron scattering with special emphasis on the relation between the scattering cross section and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering experiments using polarized beam technique is outlined. The second part describes neutron and X-ray scattering investigation of the magnetic structures of DyFe{sub 4}Al{sub 8}. The Fe sublattice of the compound order at 180 K in a cycloidal structure in the basal plane of the bct crystal structure. At 25 K the ordering of the Dy sublattice shows up. By the element specific technique of X-ray resonant magnetic scattering, the basal plane cycloidal structure was also found for the Dy sublattice. The work also includes neutron scattering studies of DyFe{sub 4}Al{sub 8} in magnetic fields up to 5 T applied along a <110> direction. The modulated structure at the Dy sublattice is quenched by a field lower than 1 T, whereas modulation is present at the Fe sublattice even when the 5 T field is applied. In the third part of the report, results from three small angle neutron experiments on MnSi are presented. At ambient pressure, a MnSi is known to form a helical spin density wave at temperature below 29 K. The application of 4.5 kbar pressure intended as hydrostatic decreased the Neel temperature to 25 K and changed the orientation of the modulation vector. To understand this reorientation within the current theoretical framework, anisotropic deformation of the sample crystal must be present. The development of magnetic critical scattering with an isotropic distribution of intensity has been studied at a level of detail higher than that of work found in the literature. Finally the potential of a novel polarization
Calculation of electron-helium scattering
Energy Technology Data Exchange (ETDEWEB)
Fursa, D.V.; Bray, I.
1994-11-01
We present the Convergent Close-Coupling (CCC) theory for the calculation of electron-helium scattering. We demonstrate its applicability at a range of projectile energies of 1.5 to 500 eV to scattering from the ground state to n {<=}3 states. Excellent agreement with experiment is obtained with the available differential, integrated, ionization, and total cross sections, as well as with the electron-impact coherence parameters up to and including the 3{sup 3} D state excitation. Comparison with other theories demonstrates that the CCC theory is the only general reliable method for the calculation of electron helium scattering. (authors). 66 refs., 2 tabs., 24 figs.
Translation Representations and Scattering By Two Intervals
Jorgensen, Palle; Tian, Feng
2012-01-01
Studying unitary one-parameter groups in Hilbert space (U(t),H), we show that a model for obstacle scattering can be built, up to unitary equivalence, with the use of translation representations for L2-functions in the complement of two finite and disjoint intervals. The model encompasses a family of systems (U (t), H). For each, we obtain a detailed spectral representation, and we compute the scattering operator, and scattering matrix. We illustrate our results in the Lax-Phillips model where (U (t), H) represents an acoustic wave equation in an exterior domain; and in quantum tunneling for dynamics of quantum states.
Scattering theory of molecules, atoms and nuclei
Canto, L Felipe
2012-01-01
The aim of the book is to give a coherent and comprehensive account of quantum scattering theory with applications to atomic, molecular and nuclear systems. The motivation for this is to supply the necessary theoretical tools to calculate scattering observables of these many-body systems. Concepts which are seemingly different for atomic/molecular scattering from those of nuclear systems, are shown to be the same once physical units such as energy and length are diligently clarified. Many-body resonances excited in nuclear systems are the same as those in atomic systems and come under the name
Slow positrons elastically scattered by solid targets
International Nuclear Information System (INIS)
Total and transport elastic scattering cross sections for positrons impinging on solid targets have been computed for energies in the range 10-10 000 eV. The phase shifts have been calculated by numerically solving the Schroedinger equation. The results have been discussed and compared where possible with other tabulations. Special attention has been given to the effect of the correlation potential. The latter was found to have much effect on the total elastic scattering cross sections while its effect on transport elastic scattering cross sections is more important when the positron energy is lowered
Neutron inelastic scattering from fumed silica
International Nuclear Information System (INIS)
Neutron inelastic scattering measurement have been performed on samples of fumed silica ('Cab-O-Sil') as a function of energy, momentum-transfer vector Q, and temperature T, and compared with analogous results for amorphous quartz. No evidence seen for a sharp crossover in the vibrational density of states of Cab-O-Sil between phonon and fracton regimes, but the inelastic scattering shows anomalous behavior in several respects. Neither the T dependence nor the Q dependence nor the absolute intensity of the scattering from Cab-O-Sil is in accord with simple phonon models. (author)
Neutron scattering studies of modulated magnetic structures
International Nuclear Information System (INIS)
This report describes investigations of the magnetic systems DyFe4Al8 and MnSi by neutron scattering and in the former case also by X-ray magnetic resonant scattering. The report is divided into three parts: An introduction to the technique of neutron scattering with special emphasis on the relation between the scattering cross section and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering experiments using polarized beam technique is outlined. The second part describes neutron and X-ray scattering investigation of the magnetic structures of DyFe4Al8. The Fe sublattice of the compound order at 180 K in a cycloidal structure in the basal plane of the bct crystal structure. At 25 K the ordering of the Dy sublattice shows up. By the element specific technique of X-ray resonant magnetic scattering, the basal plane cycloidal structure was also found for the Dy sublattice. The work also includes neutron scattering studies of DyFe4Al8 in magnetic fields up to 5 T applied along a direction. The modulated structure at the Dy sublattice is quenched by a field lower than 1 T, whereas modulation is present at the Fe sublattice even when the 5 T field is applied. In the third part of the report, results from three small angle neutron experiments on MnSi are presented. At ambient pressure, a MnSi is known to form a helical spin density wave at temperature below 29 K. The application of 4.5 kbar pressure intended as hydrostatic decreased the Neel temperature to 25 K and changed the orientation of the modulation vector. To understand this reorientation within the current theoretical framework, anisotropic deformation of the sample crystal must be present. The development of magnetic critical scattering with an isotropic distribution of intensity has been studied at a level of detail higher than that of work found in the literature. Finally the potential of a novel polarization device for small angle neutron scattering is
Production and scattering of a positronium beam
International Nuclear Information System (INIS)
Progress in the field of positronium beam-production and scattering is reviewed. A useful beam of positronium is obtained in the energy range 10-250 eV by scattering positrons from H2 and N2. With such a beam, total positronium - atom/molecule scattering cross-sections and integrated and differential fragmentation cross-sections have been measured. Results are presented and compared with recent theoretical determinations. First results for the absolute differential positronium formation cross-sections are also presented
Scalar scattering via conformal higher spin exchange
Joung, Euihun; Nakach, Simon; Tseytlin, Arkady A.
2016-02-01
Theories containing infinite number of higher spin fields require a particular definition of summation over spins consistent with their underlying symmetries. We consider a model of massless scalars interacting (via bilinear conserved currents) with conformal higher spin fields in flat space. We compute the tree-level four-scalar scattering amplitude using a natural prescription for summation over an infinite set of conformal higher spin exchanges and find that it vanishes. Independently, we show that the vanishing of the scalar scattering amplitude is, in fact, implied by the global conformal higher spin symmetry of this model. We also discuss one-loop corrections to the four-scalar scattering amplitude.
Inclusive inelastic electron scattering from nuclei
Fomin, Nadia
2007-01-01
Inclusive electron scattering from nuclei at large x and $Q^2$ is the result of a reaction mechanism that includes both quasi--elastic scattering from nucleons and deep inelastic scattering from the quark constituents of the nucleons. Data in this regime can be used to study a wide variety of topics, including the extraction of nuclear momentum distributions, the influence of final state interactions and the approach to $y$-scaling, the strength of nucleon-nucleon correlations, and the approach to $x$- scaling, to name a few. Selected results from the recent experiment E02-019 at the Thomas Jefferson National Accelerator Facility will be shown and their relevance discussed.
Low energy elastic scattering from toluene
Sakaamini, Ahmad; Hargreaves, Leigh; Khakoo, Murtadha A.; Pastega, Diego Farago; Bettega, Marcio H. F.
2015-09-01
Differential scattering cross sections for elastic scattering of low-energy electrons from toluene are presented in the form of experimental and theoretical (Schwinger multichannel method with pseudopotentials) results. The experimental incident electron energy range is from 1 eV to 20 eV and scattering angles from 15 to 130 degrees. Comparisons with other available cross sections are also presented. CSUF is funded by an NSF-PHY-RUI grant; U. Federal do Parana is funded by CNPq, CAPES and Finep.
Multiple Coulomb scattering in thin silicon
International Nuclear Information System (INIS)
We present a measurement of multiple Coulomb scattering of 1 to 6 GeV/c electrons in thin (50–140 μm) silicon targets. The data were obtained with the EUDET telescope Aconite at DESY and are compared to parametrisations as used in the Geant4 software package. We find good agreement between data and simulation in the scattering distribution width but large deviations in the shape of the distribution. In order to achieve a better description of the shape, a new scattering model based on a Student's t distribution is developed and compared to the data
Nuclear deformation from fast neutron scattering
International Nuclear Information System (INIS)
Investigations of nuclear deformation through fast neutron scattering are reviewed in some detail. In recent years, experimental methods and techniques have been considerably improved and have permitted precise cross section measurements for neutron elastic scattering and inelastic scattering to the first collective excited levels of a large number of vibrational nuclei. Analyses of these experimental data using the conventional non-spherical optical potential model are discussed with special emphasis on the choice of the optical potential parameterization. The nuclear deformations derived from these analyses are presented and compared to results obtained using other nuclear probes, and to predictions from theoretical calculations
Graviton and gluon scattering from first principles
Boels, Rutger H
2016-01-01
Graviton and gluon scattering are studied from minimal physical assumptions such as Poincare and gauge symmetry as well as unitarity. The assumptions lead to an interesting and surprisingly restrictive set of linear equations. This shows gluon and graviton scattering to be related in many field and string theories, explaining and extending several known results. By systematic analysis exceptional graviton scattering amplitudes are derived which in general dimensions can not be related to gluon amplitudes. The simplicity of the formalism guarantees wide further applicability to gauge and gravity theories.
Calculation of electron-helium scattering
International Nuclear Information System (INIS)
We present the Convergent Close-Coupling (CCC) theory for the calculation of electron-helium scattering. We demonstrate its applicability at a range of projectile energies of 1.5 to 500 eV to scattering from the ground state to n ≤3 states. Excellent agreement with experiment is obtained with the available differential, integrated, ionization, and total cross sections, as well as with the electron-impact coherence parameters up to and including the 33 D state excitation. Comparison with other theories demonstrates that the CCC theory is the only general reliable method for the calculation of electron helium scattering. (authors). 66 refs., 2 tabs., 24 figs
Particle scattering applications in solar panels
Seneviratne, Jehan; Berg, Matthew
2014-03-01
The focus of this work is to apply the scattering characteristics of particles to model particle assisted solar concentrators. In this work, the scattering patterns of particles of different shapes, sizes, and refractive indices are computationally studied using Discrete Dipole Approximation (DDA). The study investigates the optical behavior of different particle ensembles. The simulated results are used to explain the characteristic behavior seen in. The computational methodology can be used to determine the ideal ensemble of particles to produce the most efficient energy yield in a scattering-based photovoltaic concentrator.
Isospin odd pi K scattering length
J. Schweizer
2005-01-01
We make use of the chiral two-loop representation of the pi K scattering amplitude [J. Bijnens, P. Dhonte and P. Talavera, JHEP 0405 (2004) 036] to investigate the isospin odd scattering length at next-to-next-to-leading order in the SU(3) expansion. This scattering length is protected against contributions of m_s in the chiral expansion, in the sense that the corrections to the current algebra result are of order M_pi^2. In view of the planned lifetime measurement on pi K atoms at CERN it is...
Cluster decomposition of multiparticle scattering operators
International Nuclear Information System (INIS)
Cluster properties of multiparticle scattering operators defined in terms of a separation variable are shown to be equivalent to cluster properties specified in terms of an angular variable. It is shown that these formulations lead to a formulation of cluster properties in terms of an angular momentum limit. Finally, using a spectral representation of the scattering operators derived from unitarity, the author shows that scattering operators satisfy cluster requirements if the eigenvectors in the spectral representation split into products of eigenvectors in the large-angular-momentum limit
Bulk hydrogen analysis by neutron scattering
International Nuclear Information System (INIS)
The efforts of the UCT-based group now working on bulk analysis using neutrons are directed mainly towards developing methods for detecting concealed explosive or other hidden contraband, such as drugs. The technique which we are developing, called fast neutron scattering analysis (FNSA), is based on the detection and measurement of hydrogen and other elements, particularly carbon, nitrogen and oxygen, by means of fast neutron scattering measurements. This report describes progress achieved over the past year in the work on fast neutron scattering analysis and in the development of detection techniques for plastic land mines
Medium energy hadron scattering from nuclei
International Nuclear Information System (INIS)
The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154Sm and 154Gd. 27 refs., 5 figs., 1 tab
Critical Magnetic Scattering of Neutrons in Iron
DEFF Research Database (Denmark)
Passell, L.; Blinowski, K.; Brun, T.;
1964-01-01
scattered at small angles in iron and determined the spin correlation range 1∕κ1 and a parameter Λ associated with the lifetime of the fluctuations. Our results confirm the recent observation of Jacrot, Konstantinovic, Parette, and Cribier that the scattering is not elastic even at the Curie temperature. We......The intense small‐angle scattering of low‐energy neutrons by magnetic materials near the Curie temperature has been shown by Van Hove to be directly related to the appearance of large scale fluctuations in the spin density. We have measured the angular and energy distributions of 4.27‐Å neutrons...
Nonlinear X-ray Compton Scattering
Fuchs, Matthias; Trigo, Mariano; Chen, Jian; Ghimire, Shambhu; Shwartz, Sharon; Kozina, Michael; Jiang, Mason; Henighan, Thomas; Bray, Crystal; Ndabashimiye, Georges; Bucksbaum, P. H.; Feng, Yiping; Herrmann, Sven; Carini, Gabriella; Pines, Jack
2015-01-01
X-ray scattering is a weak linear probe of matter. It is primarily sensitive to the position of electrons and their momentum distribution. Elastic X-ray scattering forms the basis of atomic structural determination while inelastic Compton scattering is often used as a spectroscopic probe of both single-particle excitations and collective modes. X-ray free-electron lasers (XFELs) are unique tools for studying matter on its natural time and length scales due to their bright and coherent ultrash...
Simulation of low-energy ion scattering
Langelaar, M. H.; Breeman, M.; Mijiritskii, A. V.; Boerma, D. O.
A new simulation program `MATCH' has been developed for a detailed analysis of low-energy ion scattering (LEIS) and recoiling data. Instead of performing the full calculation of the three-dimensional trajectories through the sample from the ion source towards the detector, incoming trajectories as well as reversed-time outgoing trajectories are calculated, separately. Finally, these trajectories are matched to obtain the yield. The program has been tested for spectra and azimuthal scans of scattering and recoiling events of various sample species in different scattering geometries.
Techniques in high pressure neutron scattering
Klotz, Stefan
2013-01-01
Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea
Projection-operator approach to potential scattering
International Nuclear Information System (INIS)
The projection-operator approach of Feshbach is applied to potential scattering. The aim is to describe single-particle or shape resonances in a mathematically rigorous manner as discrete states interacting with a continuum, in analogy to the well-known description of closed-channel resonances in scattering from targets with internal degrees of freedom. A projection operator Q is defined as Q = summation= 1/sup N/ Vertical Barchi/sub ν/>] is an arbitrary orthonormal set of L2 functions. The complementary P space is spanned by a set of scattering states obtained in explicit form by orthogonalizing the free continuum to the set
Scattering of Slow Neutrons by Gaseous Methane
International Nuclear Information System (INIS)
Slow neutron scattering by molecular gases is discussed. The most detailed comparison between theoretical and experimental results has been on gaseous methane which shows conclusively that the quantum nature of the rotational levels must be explicitly taken into account to obtain agreement with the experimental results. It is also shown theoretically that interference scattering, that is interference scattering between two distinct atoms of the molecule, has an effect which can be observed. This effect has been observed experimentally in methane and apparently also for propane. It is pointed out that the theory makes quite definite predictions at smaller momentum transfers than has been measured. Thus experiments at smaller momentum transfers are needed. (author)
Carrier scattering in metals and semiconductors
Gantmakher, VF
1987-01-01
The transport properties of solids, as well as the many optical phenomena in them are determined by the scattering of current carriers. ``Carrier Scattering in Metals and Semiconductors'' elucidates the state of the art in the research on the scattering mechanisms for current carriers in metals and semiconductors and describes experiments in which these mechanisms are most dramatically manifested.The selection and organization of the material is in a form to prepare the reader to reason independently and to deal just as independently with available theoretical results and experimental
DUST SCATTERING IN TURBULENT MEDIA: CORRELATION BETWEEN THE SCATTERED LIGHT AND DUST COLUMN DENSITY
International Nuclear Information System (INIS)
Radiative transfer models in a spherical, turbulent interstellar medium (ISM), in which the photon source is situated at the center, are calculated to investigate the correlation between the scattered light and the dust column density. The medium is modeled using fractional Brownian motion structures that are appropriate for turbulent ISM. The correlation plot between the scattered light and optical depth shows substantial scatter and deviation from simple proportionality. It was also found that the overall density contrast is smoothed out in scattered light. In other words, there is an enhancement of the dust-scattered flux in low-density regions, while the scattered flux is suppressed in high-density regions. The correlation becomes less significant as the scattering becomes closer to being isotropic and the medium becomes more turbulent. Therefore, the scattered light observed in near-infrared wavelengths would show much weaker correlation than the observations in optical and ultraviolet wavelengths. We also find that the correlation plot between scattered lights at two different wavelengths shows a tighter correlation than that of the scattered light versus the optical depth
Imaging deep within a scattering medium using collective accumulation of single-scattered waves
Kang, Sungsam; Jeong, Seungwon; Choi, Wonjun; Ko, Hakseok; Yang, Taeseok D.; Joo, Jang Ho; Lee, Jae-Seung; Lim, Yong-Sik; Park, Q.-Han; Choi, Wonshik
2015-04-01
Optical microscopy suffers from a loss of resolving power when imaging targets are embedded in thick scattering media because of the dominance of strong multiple-scattered waves over waves scattered only a single time by the targets. Here, we present an approach that maintains full optical resolution when imaging deep within scattering media. We use both time-gated detection and spatial input-output correlation to identify those reflected waves that conserve in-plane momentum, which is a property of single-scattered waves. By implementing a superradiance-like collective accumulation of the single-scattered waves, we enhance the ratio of the single scattering signal to the multiple scattering background by more than three orders of magnitude. An imaging depth of 11.5 times the scattering mean free path is achieved with a near-diffraction-limited resolution of 1.5 μm. Our method of distinguishing single- from multiple-scattered waves will open new routes to deep-tissue imaging and studying the physics of the interaction of light with complex media.
International Nuclear Information System (INIS)
The authors propose a combined scatter reduction and correction method to improve image quality in cone beam computed tomography (CBCT). The scatter kernel superposition (SKS) method has been used occasionally in previous studies. However, this method differs in that a scatter detecting blocker (SDB) was used between the X-ray source and the tested object to model the self-adaptive scatter kernel. This study first evaluates the scatter kernel parameters using the SDB, and then isolates the scatter distribution based on the SKS. The quality of image can be improved by removing the scatter distribution. The results show that the method can effectively reduce the scatter artifacts, and increase the image quality. Our approach increases the image contrast and reduces the magnitude of cupping. The accuracy of the SKS technique can be significantly improved in our method by using a self-adaptive scatter kernel. This method is computationally efficient, easy to implement, and provides scatter correction using a single scan acquisition. (authors)
Inelastic neutron scattering MAX phase
International Nuclear Information System (INIS)
The ability to produce new materials at a rapid rate has meant that the process of thoroughly investigating and characterizing them through experimentation is struggling to keep apace. This is particularly the case for properties such as the elastic stiffness tensor that can best be measured using single crystal samples which because of the speed of development may not be available. With the advent of computational materials science simulation packages properties not experimentally accessible are able to be studied to some extent. A material experiencing this rapid development process with limited experimental accessibility to properties is MAX phase ceramics, in this research the archetype Ti3SiC2. Publications of DFT based elastic tensors are readily available and are general agreement with values for over 250 MAX phase materials and for Ti3SiC2 the elastic tensor c44=158GPa. Using elastic neutron scattering and developing their own stress/strain method Kisi et al. measured this elastic tensor experimentally and got c44=440GPa. With the help of ANSTO and AINSE my research has focused on firstly verifying the simulation represented the physical reality of the material and its impact on the value of c44. Starting with verifying the simulation of Ti3SiC2, a DFT and DFT-MD model was provided by Kearley and Kutteh of ANSTO. Using the AMRFP grant in 2010 a Density of States was measured on Pharos, at LANSCE, USA. Directly comparing the simulated and experimentally measured DOS over a range of low temperatures clearly showed the simulation does not encapsulate all the physical phenomena. Delving into the simulation it was shown that although assumed to be moving harmonically the Si was displaying anharmonic motion not accounted for when calculating the elastic tensor. Also identified were a set of low energy peaks not predicted by the simulation.
The Harwell back-scattering spectrometer
International Nuclear Information System (INIS)
Neutron diffraction spectra in which both high resolution (Δ Q/Q approximately equal to 0.003) and high intensity are maintained up to scattering vectors as high as 30A-1(sin theta/lambda = 2.5) have been obtained with the back-scattering spectrometer (BSS) recently installed on the Harwell electron linac. The theory behind the spectrometer design is described, and it is shown how the above resolution requirement leads to its basic features of a 12m incident flight path, a 2m scattering flight path and a scattering angle (2theta) acceptance from 1650 to 1750. Examples of the resolution, intensity and background are given. It is shown that the problem of frame overlap may be overcome by using an absorbing filter. (author)
Improvement in Rayleigh Scattering Measurement Accuracy
Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.
2012-01-01
Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous velocity, density, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of an acousto-optic frequency shifting device to improve measurement accuracy in Rayleigh scattering experiments at the NASA Glenn Research Center. The frequency shifting device is used as a means of shifting the incident or reference laser frequency by 1100 MHz to avoid overlap of the Rayleigh and reference signal peaks in the interference pattern used to obtain the velocity, density, and temperature measurements, and also to calibrate the free spectral range of the Fabry-Perot etalon. The measurement accuracy improvement is evaluated by comparison of Rayleigh scattering measurements acquired with and without shifting of the reference signal frequency in a 10 mm diameter subsonic nozzle flow.
Light scattering in glass-ceramics
International Nuclear Information System (INIS)
Full text: Glass-ceramic materials with microstructures comprised of dispersed nanocrystallites in a residual glass matrix show promise for many new technological applications. In particular, transparent glass-ceramics offer low thermal expansion and stability, in addition to the prospect of novel non-linear optical properties that can arise from the nanocrystallites. Good transparency requires low optical scattering and low atomic absorption. Light scattering in the glass-ceramic arises primarily from the glass-crystallite interface. The attenuation due to scattering (turbidity) will depend upon the difference in refractive index of the two phases and the size and distribution of nanocrystallites in the glass. Here we consider models of glass-ceramic structure formation and look at scattering in these model structures to increase our understanding of the transparency of glass-ceramics
Conformal bootstrap, universality and gravitational scattering
Directory of Open Access Journals (Sweden)
Steven Jackson
2015-12-01
Full Text Available We use the conformal bootstrap equations to study the non-perturbative gravitational scattering between infalling and outgoing particles in the vicinity of a black hole horizon in AdS. We focus on irrational 2D CFTs with large c and only Virasoro symmetry. The scattering process is described by the matrix element of two light operators (particles between two heavy states (BTZ black holes. We find that the operator algebra in this regime is (i universal and identical to that of Liouville CFT, and (ii takes the form of an exchange algebra, specified by an R-matrix that exactly matches the scattering amplitude of 2+1 gravity. The R-matrix is given by a quantum 6j-symbol and the scattering phase by the volume of a hyperbolic tetrahedron. We comment on the relevance of our results to scrambling and the holographic reconstruction of the bulk physics near black hole horizons.
Small-angle neutron-scattering experiments
International Nuclear Information System (INIS)
A brief introduction to small-angle scattering (SAS) is given. Initial results obtained using the AERE small-angle diffractometer are presented for four materials of interest: doped uranium dioxide, nitrided steel, graphite and alumina. (U.K.)
High Efficiency Low Scatter Echelle Grating Project
National Aeronautics and Space Administration — A high efficiency low scatter echelle grating will be developed using a novel technique of multiple diamond shaving cuts. The grating will have mirror surfaces on...
On the scattering power of radiotherapy protons
Gottschalk, Bernard
2009-01-01
Scattering power (T = d/dx of mean squared multiple Coulomb scattering (MCS) angle), as used in proton transport theory, is properly viewed as a differential description of the Gaussian approximation to MCS theories such as Moliere's. That is, we seek a function T which, when integrated over a finite slab, will recover the Moliere/Fano/Hanson angle for that slab. To be accurate, T must include a single scattering correction, which means mathematically it must be nonlocal, depending on how much MCS has taken place as well as the energy and scattering material at the POI. We review five formulas for T and introduce a sixth, testing each against the Moliere/Fano/Hanson prediction as well as experimental data. We discuss how sensitive some practical problems are to the choice of T. That choice is probably most important for general Monte Carlo codes, which are expected to address a wide variety of problems.
Soft particle production in deep inelastic scattering
International Nuclear Information System (INIS)
Results on the analysis of the hadronic final state in neutral current deep inelastic scattering at HERA are presented; recent results on inclusive single particle distributions, particle correlations and event shapes are highlighted. (author)
Topographical scattering of waves: a spectral approach
Magne, R; Rey, V; Herbers, T H C; Magne, Rudy; Ardhuin, Fabrice; Rey, Vincent; Herbers, Thomas H. C.
2005-01-01
The topographical scattering of gravity waves is investigated using a spectral energy balance equation that accounts for first order wave-bottom Bragg scattering. This model represents the bottom topography and surface waves with spectra, and evaluates a Bragg scattering source term that is theoretically valid for small bottom and surface slopes and slowly varying spectral properties. The robustness of the model is tested for a variety of topographies uniform along one horizontal dimension including nearly sinusoidal, linear ramp and step profiles. Results are compared with reflections computed using an accurate method that applies integral matching along vertical boundaries of a series of steps. For small bottom amplitudes, the source term representation yields accurate reflection estimates even for a localized scatterer. This result is proved for small bottom amplitudes $h$ relative to the mean water depth $H$. Wave reflection by small amplitude bottom topography thus depends primarily on the bottom elevati...
On the theory of scattering photospheres
International Nuclear Information System (INIS)
The problem is considered of the spectrum determination of a star in the photosphere of which, along with the true absorption, there takes place also radiation scattering. It is assumed that the ratio of the true absorption coefficient to the scattering coefficient is depth-dependent. The intensity of radiation emitted from the photosphere is expressed in terms of the function phi(eta, tau), which has been introduced earlier in solving the problem of diffuse reflection of light from an inhomogeneous medium. The case when the albedo of single scattering decreases exponentially with the optical depth is specially considered. For this case, the tables of auxiliary quantities, through which the radiation intensity is expressed, are presented. The obtained results may be applied to the photospheres of both hot and cold stars, in which the scattering centres are represented by free electrons and molecules, respectively
Holomorphic Factorization of Superstring Scattering Amplitudes
Institute of Scientific and Technical Information of China (English)
Simon Davis
2011-01-01
The holomorphic factorization of the superstring partition function is verified at arbitrary genus.The evaluation of scattering amplitudes and the implications of genus-dependent estimates on the string coupling are given.
Analytic scattering kernels for neutron thermalization studies
International Nuclear Information System (INIS)
Current plans call for the inclusion of a liquid hydrogen or deuterium cold source in the NRU replacement vessel. This report is part of an ongoing study of neutron thermalization in such a cold source. Here, we develop a simple analytical model for the scattering kernel of monatomic and diatomic liquids. We also present the results of extensive numerical calculations based on this model for liquid hydrogen, liquid deuterium, and mixtures of the two. These calculations demonstrate the dependence of the scattering kernel on the incident and scattered-neutron energies, the behavior near rotational thresholds, the dependence on the centre-of-mass pair correlations, the dependence on the ortho concentration, and the dependence on the deuterium concentration in H2/D2 mixtures. The total scattering cross sections are also calculated and compared with available experimental results